civetweb.c

/* Copyright (c) 2013-2016 the Civetweb developers
* Copyright (c) 2004-2013 Sergey Lyubka
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/


#if defined(_WIN32)
#if !defined(_CRT_SECURE_NO_WARNINGS)
#define _CRT_SECURE_NO_WARNINGS /* Disable deprecation warning in VS2005 */
#endif
#ifndef _WIN32_WINNT /* defined for tdm-gcc so we can use getnameinfo */
#define _WIN32_WINNT 0x0501
#endif
#else
#if defined(__GNUC__) && !defined(_GNU_SOURCE)
#define _GNU_SOURCE /* for setgroups() */
#endif
#if defined(__linux__) && !defined(_XOPEN_SOURCE)
#define _XOPEN_SOURCE 600 /* For flockfile() on Linux */
#endif
#ifndef _LARGEFILE_SOURCE
#define _LARGEFILE_SOURCE /* For fseeko(), ftello() */
#endif
#ifndef _FILE_OFFSET_BITS
#define _FILE_OFFSET_BITS 64 /* Use 64-bit file offsets by default */
#endif
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS /* <inttypes.h> wants this for C++ */
#endif
#ifndef __STDC_LIMIT_MACROS
#define __STDC_LIMIT_MACROS /* C++ wants that for INT64_MAX */
#endif
#ifdef __sun
#define __EXTENSIONS__  /* to expose flockfile and friends in stdio.h */
#define __inline inline /* not recognized on older compiler versions */
#endif
#endif

#if defined(USE_LUA) && defined(USE_WEBSOCKET)
#define USE_TIMERS
#endif

#if defined(_MSC_VER)
/* 'type cast' : conversion from 'int' to 'HANDLE' of greater size */
#pragma warning(disable : 4306)
/* conditional expression is constant: introduced by FD_SET(..) */
#pragma warning(disable : 4127)
/* non-constant aggregate initializer: issued due to missing C99 support */
#pragma warning(disable : 4204)
/* padding added after data member */
#pragma warning(disable : 4820)
/* not defined as a preprocessor macro, replacing with '0' for '#if/#elif' */
#pragma warning(disable : 4668)
/* no function prototype given: converting '()' to '(void)' */
#pragma warning(disable : 4255)
/* function has been selected for automatic inline expansion */
#pragma warning(disable : 4711)
#endif


/* This code uses static_assert to check some conditions.
* Unfortunately some compilers still do not support it, so we have a
* replacement function here. */
#if defined(_MSC_VER) && (_MSC_VER >= 1600)
#define mg_static_assert static_assert
#elif defined(__cplusplus) && (__cplusplus >= 201103L)
#define mg_static_assert static_assert
#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
#define mg_static_assert _Static_assert
#else
char static_assert_replacement[1];
#define mg_static_assert(cond, txt)                                            \
	extern char static_assert_replacement[(cond) ? 1 : -1]
#endif

mg_static_assert(sizeof(int) == 4 || sizeof(int) == 8,
  "int data type size check");
mg_static_assert(sizeof(void *) == 4 || sizeof(void *) == 8,
  "pointer data type size check");
mg_static_assert(sizeof(void *) >= sizeof(int), "data type size check");
/* mg_static_assert(sizeof(size_t) == 4 || sizeof(size_t) == 8, "size_t data
* type size check"); */

/* DTL -- including winsock2.h works better if lean and mean */
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif

#if defined(__SYMBIAN32__)
#define NO_SSL /* SSL is not supported */
#define NO_CGI /* CGI is not supported */
#define PATH_MAX FILENAME_MAX
#endif /* __SYMBIAN32__ */

#ifndef IGNORE_UNUSED_RESULT
#define IGNORE_UNUSED_RESULT(a) ((void)((a) && 1))
#endif

#ifndef _WIN32_WCE /* Some ANSI #includes are not available on Windows CE */
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <signal.h>
#include <fcntl.h>
#endif /* !_WIN32_WCE */

#ifdef __MACH__

#define CLOCK_MONOTONIC (1)
#define CLOCK_REALTIME (2)

#include <sys/time.h>
#include <mach/clock.h>
#include <mach/mach.h>
#include <mach/mach_time.h>
#include <assert.h>


/* clock_gettime is not implemented on OSX */
int clock_gettime(int clk_id, struct timespec *t);

int
clock_gettime(int clk_id, struct timespec *t)
{
  memset(t, 0, sizeof(*t));
  if (clk_id == CLOCK_REALTIME) {
    struct timeval now;
    int rv = gettimeofday(&now, NULL);
    if (rv) {
      return rv;
    }
    t->tv_sec = now.tv_sec;
    t->tv_nsec = now.tv_usec * 1000;
    return 0;

  }
  else if (clk_id == CLOCK_MONOTONIC) {
    static uint64_t clock_start_time = 0;
    static mach_timebase_info_data_t timebase_ifo = { 0, 0 };

    uint64_t now = mach_absolute_time();

    if (clock_start_time == 0) {
      kern_return_t mach_status = mach_timebase_info(&timebase_ifo);
#if defined(DEBUG)
      assert(mach_status == KERN_SUCCESS);
#else
      /* appease "unused variable" warning for release builds */
      (void)mach_status;
#endif
      clock_start_time = now;
    }

    now = (uint64_t)((double)(now - clock_start_time)
      * (double)timebase_ifo.numer
      / (double)timebase_ifo.denom);

    t->tv_sec = now / 1000000000;
    t->tv_nsec = now % 1000000000;
    return 0;
  }
  return -1; /* EINVAL - Clock ID is unknown */
}
#endif


#include <time.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>


#ifndef MAX_WORKER_THREADS
#define MAX_WORKER_THREADS (1024 * 64)
#endif
#ifndef SOCKET_TIMEOUT_QUANTUM
#define SOCKET_TIMEOUT_QUANTUM (10000)
#endif

mg_static_assert(MAX_WORKER_THREADS >= 1,
  "worker threads must be a positive number");

#if defined(_WIN32)                                                            \
    && !defined(__SYMBIAN32__) /* WINDOWS / UNIX include block */
#include <windows.h>
#include <winsock2.h> /* DTL add for SO_EXCLUSIVE */
#include <ws2tcpip.h>

typedef const char *SOCK_OPT_TYPE;

#if !defined(PATH_MAX)
#define PATH_MAX (MAX_PATH)
#endif

#if !defined(PATH_MAX)
#define PATH_MAX (4096)
#endif

mg_static_assert(PATH_MAX >= 1, "path length must be a positive number");

#ifndef _IN_PORT_T
#ifndef in_port_t
#define in_port_t u_short
#endif
#endif

#ifndef _WIN32_WCE
#include <process.h>
#include <direct.h>
#include <io.h>
#else          /* _WIN32_WCE */
#define NO_CGI /* WinCE has no pipes */

typedef long off_t;

#define errno ((int)(GetLastError()))
#define strerror(x) (_ultoa(x, (char *)_alloca(sizeof(x) * 3), 10))
#endif /* _WIN32_WCE */

#define MAKEUQUAD(lo, hi)                                                      \
	((uint64_t)(((uint32_t)(lo)) | ((uint64_t)((uint32_t)(hi))) << 32))
#define RATE_DIFF (10000000) /* 100 nsecs */
#define EPOCH_DIFF (MAKEUQUAD(0xd53e8000, 0x019db1de))
#define SYS2UNIX_TIME(lo, hi)                                                  \
	((time_t)((MAKEUQUAD((lo), (hi)) - EPOCH_DIFF) / RATE_DIFF))

/* Visual Studio 6 does not know __func__ or __FUNCTION__
* The rest of MS compilers use __FUNCTION__, not C99 __func__
* Also use _strtoui64 on modern M$ compilers */
#if defined(_MSC_VER)
#if (_MSC_VER < 1300)
#define STRX(x) #x
#define STR(x) STRX(x)
#define __func__ __FILE__ ":" STR(__LINE__)
#define strtoull(x, y, z) ((unsigned __int64)_atoi64(x))
#define strtoll(x, y, z) (_atoi64(x))
#else
#define __func__ __FUNCTION__
#define strtoull(x, y, z) (_strtoui64(x, y, z))
#define strtoll(x, y, z) (_strtoi64(x, y, z))
#endif
#endif /* _MSC_VER */

#define ERRNO ((int)(GetLastError()))
#define NO_SOCKLEN_T
#define SSL_LIB "ssleay32.dll"
#define CRYPTO_LIB "libeay32.dll"
#define O_NONBLOCK (0)
#ifndef W_OK
#define W_OK (2) /* http://msdn.microsoft.com/en-us/library/1w06ktdy.aspx */
#endif
#if !defined(EWOULDBLOCK)
#define EWOULDBLOCK WSAEWOULDBLOCK
#endif /* !EWOULDBLOCK */
#define _POSIX_
#define INT64_FMT "I64d"
#define UINT64_FMT "I64u"

#define WINCDECL __cdecl
#define SHUT_RD (0)
#define SHUT_WR (1)
#define SHUT_BOTH (2)
#define vsnprintf_impl _vsnprintf
#define access _access
#define mg_sleep(x) (Sleep(x))

#define pipe(x) _pipe(x, MG_BUF_LEN, _O_BINARY)
#ifndef popen
#define popen(x, y) (_popen(x, y))
#endif
#ifndef pclose
#define pclose(x) (_pclose(x))
#endif
#define close(x) (_close(x))
#define dlsym(x, y) (GetProcAddress((HINSTANCE)(x), (y)))
#define RTLD_LAZY (0)
#define fseeko(x, y, z) (_lseeki64(_fileno(x), (y), (z)) == -1 ? -1 : 0)
#define fdopen(x, y) (_fdopen((x), (y)))
#define write(x, y, z) (_write((x), (y), (unsigned)z))
#define read(x, y, z) (_read((x), (y), (unsigned)z))
#define flockfile(x) (EnterCriticalSection(&global_log_file_lock))
#define funlockfile(x) (LeaveCriticalSection(&global_log_file_lock))
#define sleep(x) (Sleep((x)*1000))
#define rmdir(x) (_rmdir(x))
#define timegm(x) (_mkgmtime(x))

#if !defined(fileno)
#define fileno(x) (_fileno(x))
#endif /* !fileno MINGW #defines fileno */

typedef HANDLE pthread_mutex_t;
typedef DWORD pthread_key_t;
typedef HANDLE pthread_t;
typedef struct {
  CRITICAL_SECTION threadIdSec;
  int waitingthreadcount;       /* The number of threads queued. */
  pthread_t *waitingthreadhdls; /* The thread handles. */
} pthread_cond_t;

#ifndef __clockid_t_defined
typedef DWORD clockid_t;
#endif
#ifndef CLOCK_MONOTONIC
#define CLOCK_MONOTONIC (1)
#endif
#ifndef CLOCK_REALTIME
#define CLOCK_REALTIME (2)
#endif

#if defined(_MSC_VER) && (_MSC_VER >= 1900)
#define _TIMESPEC_DEFINED
#endif
#ifndef _TIMESPEC_DEFINED
struct timespec {
  time_t tv_sec; /* seconds */
  long tv_nsec;  /* nanoseconds */
};
#endif

#define pid_t HANDLE /* MINGW typedefs pid_t to int. Using #define here. */

static int pthread_mutex_lock(pthread_mutex_t *);
static int pthread_mutex_unlock(pthread_mutex_t *);
static void to_unicode(const char *path, wchar_t *wbuf, size_t wbuf_len);
struct file;
static char *mg_fgets(char *buf, size_t size, struct file *filep, char **p);

#if defined(HAVE_STDINT)
#include <stdint.h>
#else
typedef unsigned char uint8_t;
typedef unsigned short uint16_t;
typedef unsigned int uint32_t;
typedef unsigned __int64 uint64_t;
typedef __int64 int64_t;
#define INT64_MAX (9223372036854775807)
#endif /* HAVE_STDINT */

/* POSIX dirent interface */
struct dirent {
  char d_name[PATH_MAX];
};

typedef struct DIR {
  HANDLE handle;
  WIN32_FIND_DATAW info;
  struct dirent result;
} DIR;

#if defined(_WIN32) && !defined(POLLIN)
#ifndef HAVE_POLL
struct pollfd {
  SOCKET fd;
  short events;
  short revents;
};
#define POLLIN (0x0300)
#endif
#endif

/* Mark required libraries */
#if defined(_MSC_VER)
#pragma comment(lib, "Ws2_32.lib")
#endif

#else /* defined(_WIN32) && !defined(__SYMBIAN32__) - WINDOWS / UNIX include   \
           block */

#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/poll.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <sys/utsname.h>
#include <stdint.h>
#include <inttypes.h>
#include <netdb.h>
#include <netinet/tcp.h>
typedef const void *SOCK_OPT_TYPE;

#if defined(ANDROID)
typedef unsigned short int in_port_t;
#endif

#include <pwd.h>
#include <unistd.h>
#include <grp.h>
#include <dirent.h>
#define vsnprintf_impl vsnprintf

#if !defined(NO_SSL_DL) && !defined(NO_SSL)
#include <dlfcn.h>
#endif
#include <pthread.h>
#if defined(__MACH__)
#define SSL_LIB "libssl.dylib"
#define CRYPTO_LIB "libcrypto.dylib"
#else
#if !defined(SSL_LIB)
#define SSL_LIB "libssl.so"
#endif
#if !defined(CRYPTO_LIB)
#define CRYPTO_LIB "libcrypto.so"
#endif
#endif
#ifndef O_BINARY
#define O_BINARY (0)
#endif /* O_BINARY */
#define closesocket(a) (close(a))
#define mg_mkdir(x, y) (mkdir(x, y))
#define mg_remove(x) (remove(x))
#define mg_sleep(x) (usleep((x)*1000))
#define ERRNO (errno)
#define INVALID_SOCKET (-1)
#define INT64_FMT PRId64
#define UINT64_FMT PRIu64
typedef int SOCKET;
#define WINCDECL

#if defined(__hpux)
/* HPUX 11 does not have monotonic, fall back to realtime */
#ifndef CLOCK_MONOTONIC
#define CLOCK_MONOTONIC CLOCK_REALTIME
#endif

/* HPUX defines socklen_t incorrectly as size_t which is 64bit on
* Itanium.  Without defining _XOPEN_SOURCE or _XOPEN_SOURCE_EXTENDED
* the prototypes use int* rather than socklen_t* which matches the
* actual library expectation.  When called with the wrong size arg
* accept() returns a zero client inet addr and check_acl() always
* fails.  Since socklen_t is widely used below, just force replace
* their typedef with int. - DTL
*/
#define socklen_t int
#endif /* hpux */

#endif /* defined(_WIN32) && !defined(__SYMBIAN32__) - WINDOWS / UNIX include  \
          block */

/* va_copy should always be a macro, C99 and C++11 - DTL */
#ifndef va_copy
#define va_copy(x, y) ((x) = (y))
#endif

#ifdef _WIN32
/* Create substitutes for POSIX functions in Win32. */

#if defined(__MINGW32__)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif


static CRITICAL_SECTION global_log_file_lock;
static DWORD
pthread_self(void)
{
  return GetCurrentThreadId();
}


static int
pthread_key_create(
  pthread_key_t *key,
  void(*_ignored)(void *) /* destructor not supported for Windows */
  )
{
  (void)_ignored;

  if ((key != 0)) {
    *key = TlsAlloc();
    return (*key != TLS_OUT_OF_INDEXES) ? 0 : -1;
  }
  return -2;
}


static int
pthread_key_delete(pthread_key_t key)
{
  return TlsFree(key) ? 0 : 1;
}


static int
pthread_setspecific(pthread_key_t key, void *value)
{
  return TlsSetValue(key, value) ? 0 : 1;
}


static void *
pthread_getspecific(pthread_key_t key)
{
  return TlsGetValue(key);
}

#if defined(__MINGW32__)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif

static struct pthread_mutex_undefined_struct *pthread_mutex_attr = NULL;
#else
static pthread_mutexattr_t pthread_mutex_attr;
#endif /* _WIN32 */


#include "civetweb.h"


#define PASSWORDS_FILE_NAME ".htpasswd"
#define CGI_ENVIRONMENT_SIZE (4096)
#define MAX_CGI_ENVIR_VARS (256)
#define MG_BUF_LEN (8192)

#ifndef MAX_REQUEST_SIZE
#define MAX_REQUEST_SIZE (16384)
#endif

mg_static_assert(MAX_REQUEST_SIZE >= 256,
  "request size length must be a positive number");

#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))

#if !defined(DEBUG_TRACE)
#if defined(DEBUG)


static void DEBUG_TRACE_FUNC(const char *func,
  unsigned line,
  PRINTF_FORMAT_STRING(const char *fmt),
  ...) PRINTF_ARGS(3, 4);

static void
DEBUG_TRACE_FUNC(const char *func, unsigned line, const char *fmt, ...)
{
  va_list args;
  flockfile(stdout);
  printf("*** %lu.%p.%s.%u: ",
    (unsigned long)time(NULL),
    (void *)pthread_self(),
    func,
    line);
  va_start(args, fmt);
  vprintf(fmt, args);
  va_end(args);
  putchar('\n');
  fflush(stdout);
  funlockfile(stdout);
}

#define DEBUG_TRACE(fmt, ...)                                                  \
	DEBUG_TRACE_FUNC(__func__, __LINE__, fmt, __VA_ARGS__)

#else
#define DEBUG_TRACE(fmt, ...)                                                  \
	do {                                                                       \
	} while (0)
#endif /* DEBUG */
#endif /* DEBUG_TRACE */

#if defined(MEMORY_DEBUGGING)
unsigned long mg_memory_debug_blockCount = 0;
unsigned long mg_memory_debug_totalMemUsed = 0;


static void *
mg_malloc_ex(size_t size, const char *file, unsigned line)
{
  void *data = malloc(size + sizeof(size_t));
  void *memory = 0;
  char mallocStr[256];

  if (data) {
    *(size_t *)data = size;
    mg_memory_debug_totalMemUsed += size;
    mg_memory_debug_blockCount++;
    memory = (void *)(((char *)data) + sizeof(size_t));
  }

  sprintf(mallocStr,
    "MEM: %p %5lu alloc   %7lu %4lu --- %s:%u\n",
    memory,
    (unsigned long)size,
    mg_memory_debug_totalMemUsed,
    mg_memory_debug_blockCount,
    file,
    line);
#if defined(_WIN32)
  OutputDebugStringA(mallocStr);
#else
  DEBUG_TRACE("%s", mallocStr);
#endif

  return memory;
}


static void *
mg_calloc_ex(size_t count, size_t size, const char *file, unsigned line)
{
  void *data = mg_malloc_ex(size * count, file, line);
  if (data) {
    memset(data, 0, size);
  }
  return data;
}


static void
mg_free_ex(void *memory, const char *file, unsigned line)
{
  char mallocStr[256];
  void *data = (void *)(((char *)memory) - sizeof(size_t));
  size_t size;

  if (memory) {
    size = *(size_t *)data;
    mg_memory_debug_totalMemUsed -= size;
    mg_memory_debug_blockCount--;
    sprintf(mallocStr,
      "MEM: %p %5lu free    %7lu %4lu --- %s:%u\n",
      memory,
      (unsigned long)size,
      mg_memory_debug_totalMemUsed,
      mg_memory_debug_blockCount,
      file,
      line);
#if defined(_WIN32)
    OutputDebugStringA(mallocStr);
#else
    DEBUG_TRACE("%s", mallocStr);
#endif

    free(data);
  }
}


static void *
mg_realloc_ex(void *memory, size_t newsize, const char *file, unsigned line)
{
  char mallocStr[256];
  void *data;
  void *_realloc;
  size_t oldsize;

  if (newsize) {
    if (memory) {
      data = (void *)(((char *)memory) - sizeof(size_t));
      oldsize = *(size_t *)data;
      _realloc = realloc(data, newsize + sizeof(size_t));
      if (_realloc) {
        data = _realloc;
        mg_memory_debug_totalMemUsed -= oldsize;
        sprintf(mallocStr,
          "MEM: %p %5lu r-free  %7lu %4lu --- %s:%u\n",
          memory,
          (unsigned long)oldsize,
          mg_memory_debug_totalMemUsed,
          mg_memory_debug_blockCount,
          file,
          line);
#if defined(_WIN32)
        OutputDebugStringA(mallocStr);
#else
        DEBUG_TRACE("%s", mallocStr);
#endif
        mg_memory_debug_totalMemUsed += newsize;
        sprintf(mallocStr,
          "MEM: %p %5lu r-alloc %7lu %4lu --- %s:%u\n",
          memory,
          (unsigned long)newsize,
          mg_memory_debug_totalMemUsed,
          mg_memory_debug_blockCount,
          file,
          line);
#if defined(_WIN32)
        OutputDebugStringA(mallocStr);
#else
        DEBUG_TRACE("%s", mallocStr);
#endif
        *(size_t *)data = newsize;
        data = (void *)(((char *)data) + sizeof(size_t));
      }
      else {
#if defined(_WIN32)
        OutputDebugStringA("MEM: realloc failed\n");
#else
        DEBUG_TRACE("%s", "MEM: realloc failed\n");
#endif
        return _realloc;
      }
    }
    else {
      data = mg_malloc_ex(newsize, file, line);
    }
  }
  else {
    data = 0;
    mg_free_ex(memory, file, line);
  }

  return data;
}

#define mg_malloc(a) mg_malloc_ex(a, __FILE__, __LINE__)
#define mg_calloc(a, b) mg_calloc_ex(a, b, __FILE__, __LINE__)
#define mg_realloc(a, b) mg_realloc_ex(a, b, __FILE__, __LINE__)
#define mg_free(a) mg_free_ex(a, __FILE__, __LINE__)

#else

static __inline void *
mg_malloc(size_t a)
{
  return malloc(a);
}

static __inline void *
mg_calloc(size_t a, size_t b)
{
  return calloc(a, b);
}

static __inline void *
mg_realloc(void *a, size_t b)
{
  return realloc(a, b);
}

static __inline void
mg_free(void *a)
{
  free(a);
}

#endif


static void mg_vsnprintf(const struct mg_connection *conn,
  int *truncated,
  char *buf,
  size_t buflen,
  const char *fmt,
  va_list ap);

static void mg_snprintf(const struct mg_connection *conn,
  int *truncated,
  char *buf,
  size_t buflen,
  PRINTF_FORMAT_STRING(const char *fmt),
  ...) PRINTF_ARGS(5, 6);

/* This following lines are just meant as a reminder to use the mg-functions
* for memory management */
#ifdef malloc
#undef malloc
#endif
#ifdef calloc
#undef calloc
#endif
#ifdef realloc
#undef realloc
#endif
#ifdef free
#undef free
#endif
#ifdef snprintf
#undef snprintf
#endif
#ifdef vsnprintf
#undef vsnprintf
#endif
/*#define malloc DO_NOT_USE_THIS_FUNCTION__USE_mg_malloc
#define calloc DO_NOT_USE_THIS_FUNCTION__USE_mg_calloc
#define realloc DO_NOT_USE_THIS_FUNCTION__USE_mg_realloc
#define free DO_NOT_USE_THIS_FUNCTION__USE_mg_free
#define snprintf DO_NOT_USE_THIS_FUNCTION__USE_mg_snprintf*/
#ifdef _WIN32 /* vsnprintf must not be used in any system, *                   \
               * but this define only works well for Windows. */
/*#define vsnprintf DO_NOT_USE_THIS_FUNCTION__USE_mg_vsnprintf*/
#endif

#define MD5_STATIC static
#include "utils/md5.h"

/* Darwin prior to 7.0 and Win32 do not have socklen_t */
#ifdef NO_SOCKLEN_T
typedef int socklen_t;
#endif /* NO_SOCKLEN_T */
#define _DARWIN_UNLIMITED_SELECT

#define IP_ADDR_STR_LEN (50) /* IPv6 hex string is 46 chars */

#if !defined(MSG_NOSIGNAL)
#define MSG_NOSIGNAL (0)
#endif

#if !defined(SOMAXCONN)
#define SOMAXCONN (100)
#endif

/* Size of the accepted socket queue */
#if !defined(MGSQLEN)
#define MGSQLEN (20)
#endif

#if defined(NO_SSL_DL)
#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/crypto.h>
#include <openssl/x509.h>
#include <openssl/pem.h>
#else
/* SSL loaded dynamically from DLL.
* I put the prototypes here to be independent from OpenSSL source
* installation. */

typedef struct ssl_st SSL;
typedef struct ssl_method_st SSL_METHOD;
typedef struct ssl_ctx_st SSL_CTX;
typedef struct x509_store_ctx_st X509_STORE_CTX;

#define SSL_CTRL_OPTIONS (32)
#define SSL_CTRL_CLEAR_OPTIONS (77)
#define SSL_CTRL_SET_ECDH_AUTO (94)

#define SSL_VERIFY_NONE (0)
#define SSL_VERIFY_PEER (1)
#define SSL_VERIFY_FAIL_IF_NO_PEER_CERT (2)
#define SSL_VERIFY_CLIENT_ONCE (4)
#define SSL_OP_ALL (0x80000BFFL)
#define SSL_OP_NO_SSLv2 (0x01000000L)
#define SSL_OP_NO_SSLv3 (0x02000000L)
#define SSL_OP_NO_TLSv1 (0x04000000L)
#define SSL_OP_NO_TLSv1_2 (0x08000000L)
#define SSL_OP_NO_TLSv1_1 (0x10000000L)
#define SSL_OP_SINGLE_DH_USE (0x00100000L)

struct ssl_func {
  const char *name;  /* SSL function name */
  void(*ptr)(void); /* Function pointer */
};

#define SSL_free (*(void (*)(SSL *))ssl_sw[0].ptr)
#define SSL_accept (*(int (*)(SSL *))ssl_sw[1].ptr)
#define SSL_connect (*(int (*)(SSL *))ssl_sw[2].ptr)
#define SSL_read (*(int (*)(SSL *, void *, int))ssl_sw[3].ptr)
#define SSL_write (*(int (*)(SSL *, const void *, int))ssl_sw[4].ptr)
#define SSL_get_error (*(int (*)(SSL *, int))ssl_sw[5].ptr)
#define SSL_set_fd (*(int (*)(SSL *, SOCKET))ssl_sw[6].ptr)
#define SSL_new (*(SSL * (*)(SSL_CTX *))ssl_sw[7].ptr)
#define SSL_CTX_new (*(SSL_CTX * (*)(SSL_METHOD *))ssl_sw[8].ptr)
#define SSLv23_server_method (*(SSL_METHOD * (*)(void))ssl_sw[9].ptr)
#define SSL_library_init (*(int (*)(void))ssl_sw[10].ptr)
#define SSL_CTX_use_PrivateKey_file                                            \
	(*(int (*)(SSL_CTX *, const char *, int))ssl_sw[11].ptr)
#define SSL_CTX_use_certificate_file                                           \
	(*(int (*)(SSL_CTX *, const char *, int))ssl_sw[12].ptr)
#define SSL_CTX_set_default_passwd_cb                                          \
	(*(void (*)(SSL_CTX *, mg_callback_t))ssl_sw[13].ptr)
#define SSL_CTX_free (*(void (*)(SSL_CTX *))ssl_sw[14].ptr)
#define SSL_load_error_strings (*(void (*)(void))ssl_sw[15].ptr)
#define SSL_CTX_use_certificate_chain_file                                     \
	(*(int (*)(SSL_CTX *, const char *))ssl_sw[16].ptr)
#define SSLv23_client_method (*(SSL_METHOD * (*)(void))ssl_sw[17].ptr)
#define SSL_pending (*(int (*)(SSL *))ssl_sw[18].ptr)
#define SSL_CTX_set_verify                                                     \
	(*(void (*)(SSL_CTX *,                                                     \
	            int,                                                           \
	            int (*verify_callback)(int, X509_STORE_CTX *)))ssl_sw[19].ptr)
#define SSL_shutdown (*(int (*)(SSL *))ssl_sw[20].ptr)
#define SSL_CTX_load_verify_locations                                          \
	(*(int (*)(SSL_CTX *, const char *, const char *))ssl_sw[21].ptr)
#define SSL_CTX_set_default_verify_paths (*(int (*)(SSL_CTX *))ssl_sw[22].ptr)
#define SSL_CTX_set_verify_depth (*(void (*)(SSL_CTX *, int))ssl_sw[23].ptr)
#define SSL_get_peer_certificate (*(X509 * (*)(SSL *))ssl_sw[24].ptr)
#define SSL_get_version (*(const char *(*)(SSL *))ssl_sw[25].ptr)
#define SSL_get_current_cipher (*(SSL_CIPHER * (*)(SSL *))ssl_sw[26].ptr)
#define SSL_CIPHER_get_name                                                    \
	(*(const char *(*)(const SSL_CIPHER *))ssl_sw[27].ptr)
#define SSL_CTX_check_private_key (*(int (*)(SSL_CTX *))ssl_sw[28].ptr)
#define SSL_CTX_set_session_id_context                                         \
	(*(int (*)(SSL_CTX *, const unsigned char *, unsigned int))ssl_sw[29].ptr)
#define SSL_CTX_ctrl (*(long (*)(SSL_CTX *, int, long, void *))ssl_sw[30].ptr)
#define SSL_CTX_set_cipher_list                                                \
	(*(int (*)(SSL_CTX *, const char *))ssl_sw[31].ptr)
#define SSL_CTX_set_options(ctx, op)                                           \
	SSL_CTX_ctrl((ctx), SSL_CTRL_OPTIONS, (op), NULL)
#define SSL_CTX_clear_options(ctx, op)                                         \
	SSL_CTX_ctrl((ctx), SSL_CTRL_CLEAR_OPTIONS, (op), NULL)
#define SSL_CTX_set_ecdh_auto(ctx, onoff)                                      \
	SSL_CTX_ctrl(ctx, SSL_CTRL_SET_ECDH_AUTO, onoff, NULL)

#define CRYPTO_num_locks (*(int (*)(void))crypto_sw[0].ptr)
#define CRYPTO_set_locking_callback                                            \
	(*(void (*)(void (*)(int, int, const char *, int)))crypto_sw[1].ptr)
#define CRYPTO_set_id_callback                                                 \
	(*(void (*)(unsigned long (*)(void)))crypto_sw[2].ptr)
#define ERR_get_error (*(unsigned long (*)(void))crypto_sw[3].ptr)
#define ERR_error_string (*(char *(*)(unsigned long, char *))crypto_sw[4].ptr)
#define ERR_remove_state (*(void (*)(unsigned long))crypto_sw[5].ptr)
#define ERR_free_strings (*(void (*)(void))crypto_sw[6].ptr)
#define ENGINE_cleanup (*(void (*)(void))crypto_sw[7].ptr)
#define CONF_modules_unload (*(void (*)(int))crypto_sw[8].ptr)
#define CRYPTO_cleanup_all_ex_data (*(void (*)(void))crypto_sw[9].ptr)
#define EVP_cleanup (*(void (*)(void))crypto_sw[10].ptr)


/* set_ssl_option() function updates this array.
* It loads SSL library dynamically and changes NULLs to the actual addresses
* of respective functions. The macros above (like SSL_connect()) are really
* just calling these functions indirectly via the pointer. */
static struct ssl_func ssl_sw[] = { { "SSL_free", NULL },
{ "SSL_accept", NULL },
{ "SSL_connect", NULL },
{ "SSL_read", NULL },
{ "SSL_write", NULL },
{ "SSL_get_error", NULL },
{ "SSL_set_fd", NULL },
{ "SSL_new", NULL },
{ "SSL_CTX_new", NULL },
{ "SSLv23_server_method", NULL },
{ "SSL_library_init", NULL },
{ "SSL_CTX_use_PrivateKey_file", NULL },
{ "SSL_CTX_use_certificate_file", NULL },
{ "SSL_CTX_set_default_passwd_cb", NULL },
{ "SSL_CTX_free", NULL },
{ "SSL_load_error_strings", NULL },
{ "SSL_CTX_use_certificate_chain_file", NULL },
{ "SSLv23_client_method", NULL },
{ "SSL_pending", NULL },
{ "SSL_CTX_set_verify", NULL },
{ "SSL_shutdown", NULL },
{ "SSL_CTX_load_verify_locations", NULL },
{ "SSL_CTX_set_default_verify_paths", NULL },
{ "SSL_CTX_set_verify_depth", NULL },
{ "SSL_get_peer_certificate", NULL },
{ "SSL_get_version", NULL },
{ "SSL_get_current_cipher", NULL },
{ "SSL_CIPHER_get_name", NULL },
{ "SSL_CTX_check_private_key", NULL },
{ "SSL_CTX_set_session_id_context", NULL },
{ "SSL_CTX_ctrl", NULL },
{ "SSL_CTX_set_cipher_list", NULL },
{ NULL, NULL } };


/* Similar array as ssl_sw. These functions could be located in different
* lib. */
#if !defined(NO_SSL)
static struct ssl_func crypto_sw[] = { { "CRYPTO_num_locks", NULL },
{ "CRYPTO_set_locking_callback", NULL },
{ "CRYPTO_set_id_callback", NULL },
{ "ERR_get_error", NULL },
{ "ERR_error_string", NULL },
{ "ERR_remove_state", NULL },
{ "ERR_free_strings", NULL },
{ "ENGINE_cleanup", NULL },
{ "CONF_modules_unload", NULL },
{ "CRYPTO_cleanup_all_ex_data", NULL },
{ "EVP_cleanup", NULL },
{ NULL, NULL } };
#endif /* NO_SSL */
#endif /* NO_SSL_DL */


static const char *month_names[] = { "Jan",
"Feb",
"Mar",
"Apr",
"May",
"Jun",
"Jul",
"Aug",
"Sep",
"Oct",
"Nov",
"Dec" };

/* Unified socket address. For IPv6 support, add IPv6 address structure in the
* union u. */
union usa {
  struct sockaddr sa;
  struct sockaddr_in sin;
#if defined(USE_IPV6)
  struct sockaddr_in6 sin6;
#endif
};

/* Describes a string (chunk of memory). */
struct vec {
  const char *ptr;
  size_t len;
};

struct file {
  uint64_t size;
  time_t last_modified;
  FILE *fp;
  const char *membuf; /* Non-NULL if file data is in memory */
  int is_directory;
  int gzipped; /* set to 1 if the content is gzipped
               * in which case we need a content-encoding: gzip header */
};

#define STRUCT_FILE_INITIALIZER                                                \
	{                                                                          \
		(uint64_t)0, (time_t)0, (FILE *)NULL, (const char *)NULL, 0, 0         \
	}

/* Describes listening socket, or socket which was accept()-ed by the master
* thread and queued for future handling by the worker thread. */
struct socket {
  SOCKET sock;             /* Listening socket */
  union usa lsa;           /* Local socket address */
  union usa rsa;           /* Remote socket address */
  unsigned char is_ssl;    /* Is port SSL-ed */
  unsigned char ssl_redir; /* Is port supposed to redirect everything to SSL
                           * port */
};

/* NOTE(lsm): this enum shoulds be in sync with the config_options below. */
enum {
  CGI_EXTENSIONS,
  CGI_ENVIRONMENT,
  PUT_DELETE_PASSWORDS_FILE,
  CGI_INTERPRETER,
  PROTECT_URI,
  AUTHENTICATION_DOMAIN,
  SSI_EXTENSIONS,
  THROTTLE,
  ACCESS_LOG_FILE,
  ENABLE_DIRECTORY_LISTING,
  ERROR_LOG_FILE,
  GLOBAL_PASSWORDS_FILE,
  INDEX_FILES,
  ENABLE_KEEP_ALIVE,
  ACCESS_CONTROL_LIST,
  EXTRA_MIME_TYPES,
  LISTENING_PORTS,
  DOCUMENT_ROOT,
  SSL_CERTIFICATE,
  NUM_THREADS,
  RUN_AS_USER,
  REWRITE,
  HIDE_FILES,
  REQUEST_TIMEOUT,
  SSL_DO_VERIFY_PEER,
  SSL_CA_PATH,
  SSL_CA_FILE,
  SSL_VERIFY_DEPTH,
  SSL_DEFAULT_VERIFY_PATHS,
  SSL_CIPHER_LIST,
  SSL_PROTOCOL_VERSION,
#if defined(USE_WEBSOCKET)
  WEBSOCKET_TIMEOUT,
#endif
  DECODE_URL,

#if defined(USE_LUA)
  LUA_PRELOAD_FILE,
  LUA_SCRIPT_EXTENSIONS,
  LUA_SERVER_PAGE_EXTENSIONS,
#endif
#if defined(USE_DUKTAPE)
  DUKTAPE_SCRIPT_EXTENSIONS,
#endif

#if defined(USE_WEBSOCKET)
  WEBSOCKET_ROOT,
#endif
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
  LUA_WEBSOCKET_EXTENSIONS,
#endif
  ACCESS_CONTROL_ALLOW_ORIGIN,
  ERROR_PAGES,
  CONFIG_TCP_NODELAY, /* Prepended CONFIG_ to avoid conflict with the
                      * socket option typedef TCP_NODELAY. */
  STATIC_FILE_MAX_AGE,

  NUM_OPTIONS
};


/* Config option name, config types, default value */
static struct mg_option config_options[] = {
  { "cgi_pattern", CONFIG_TYPE_EXT_PATTERN, "**.cgi$|**.pl$|**.php$" },
  { "cgi_environment", CONFIG_TYPE_STRING, NULL },
  { "put_delete_auth_file", CONFIG_TYPE_FILE, NULL },
  { "cgi_interpreter", CONFIG_TYPE_FILE, NULL },
  { "protect_uri", CONFIG_TYPE_STRING, NULL },
  { "authentication_domain", CONFIG_TYPE_STRING, "mydomain.com" },
  { "ssi_pattern", CONFIG_TYPE_EXT_PATTERN, "**.shtml$|**.shtm$" },
  { "throttle", CONFIG_TYPE_STRING, NULL },
  { "access_log_file", CONFIG_TYPE_FILE, NULL },
  { "enable_directory_listing", CONFIG_TYPE_BOOLEAN, "yes" },
  { "error_log_file", CONFIG_TYPE_FILE, NULL },
  { "global_auth_file", CONFIG_TYPE_FILE, NULL },
  { "index_files",
  CONFIG_TYPE_STRING,
#ifdef USE_LUA
  "index.xhtml,index.html,index.htm,index.lp,index.lsp,index.lua,index.cgi,"
  "index.shtml,index.php" },
#else
  "index.xhtml,index.html,index.htm,index.cgi,index.shtml,index.php" },
#endif
{ "enable_keep_alive", CONFIG_TYPE_BOOLEAN, "no" },
{ "access_control_list", CONFIG_TYPE_STRING, NULL },
{ "extra_mime_types", CONFIG_TYPE_STRING, NULL },
{ "listening_ports", CONFIG_TYPE_STRING, "8080" },
{ "document_root", CONFIG_TYPE_DIRECTORY, NULL },
{ "ssl_certificate", CONFIG_TYPE_FILE, NULL },
{ "num_threads", CONFIG_TYPE_NUMBER, "50" },
{ "run_as_user", CONFIG_TYPE_STRING, NULL },
{ "url_rewrite_patterns", CONFIG_TYPE_STRING, NULL },
{ "hide_files_patterns", CONFIG_TYPE_EXT_PATTERN, NULL },
{ "request_timeout_ms", CONFIG_TYPE_NUMBER, "30000" },
{ "ssl_verify_peer", CONFIG_TYPE_BOOLEAN, "no" },
{ "ssl_ca_path", CONFIG_TYPE_DIRECTORY, NULL },
{ "ssl_ca_file", CONFIG_TYPE_FILE, NULL },
{ "ssl_verify_depth", CONFIG_TYPE_NUMBER, "9" },
{ "ssl_default_verify_paths", CONFIG_TYPE_BOOLEAN, "yes" },
{ "ssl_cipher_list", CONFIG_TYPE_STRING, NULL },
{ "ssl_protocol_version", CONFIG_TYPE_NUMBER, "0" },
#if defined(USE_WEBSOCKET)
{ "websocket_timeout_ms", CONFIG_TYPE_NUMBER, "30000" },
#endif
{ "decode_url", CONFIG_TYPE_BOOLEAN, "yes" },

#if defined(USE_LUA)
{ "lua_preload_file", CONFIG_TYPE_FILE, NULL },
{ "lua_script_pattern", CONFIG_TYPE_EXT_PATTERN, "**.lua$" },
{ "lua_server_page_pattern", CONFIG_TYPE_EXT_PATTERN, "**.lp$|**.lsp$" },
#endif
#if defined(USE_DUKTAPE)
{ "_experimental_duktape_script_pattern",
CONFIG_TYPE_EXT_PATTERN,
"**.ssjs$" }, /* TODO: redefine parameter */
#endif

#if defined(USE_WEBSOCKET)
{ "websocket_root", CONFIG_TYPE_DIRECTORY, NULL },
#endif
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
{ "lua_websocket_pattern", CONFIG_TYPE_EXT_PATTERN, "**.lua$" },
#endif
{ "access_control_allow_origin", CONFIG_TYPE_STRING, "*" },
{ "error_pages", CONFIG_TYPE_DIRECTORY, NULL },
{ "tcp_nodelay", CONFIG_TYPE_NUMBER, "0" },
{ "_experimental_static_file_max_age",
CONFIG_TYPE_NUMBER,
"3600" }, /* TODO: redefine parameter */

{ NULL, CONFIG_TYPE_UNKNOWN, NULL }};

/* Check if the config_options and the corresponding enum have compatible
* sizes. */
mg_static_assert((sizeof(config_options) / sizeof(config_options[0]))
  == (NUM_OPTIONS + 1),
  "config_options and enum not sync");

enum { REQUEST_HANDLER, WEBSOCKET_HANDLER, AUTH_HANDLER };

struct mg_handler_info {
  /* Name/Pattern of the URI. */
  char *uri;
  size_t uri_len;

  /* handler type */
  int handler_type;

  /* Handler for http/https or authorization requests. */
  mg_request_handler handler;

  /* Handler for ws/wss (websocket) requests. */
  mg_websocket_connect_handler connect_handler;
  mg_websocket_ready_handler ready_handler;
  mg_websocket_data_handler data_handler;
  mg_websocket_close_handler close_handler;

  /* Handler for authorization requests */
  mg_authorization_handler auth_handler;

  /* User supplied argument for the handler function. */
  void *cbdata;

  /* next handler in a linked list */
  struct mg_handler_info *next;
};

struct mg_context {
  volatile int stop_flag;        /* Should we stop event loop */
  SSL_CTX *ssl_ctx;              /* SSL context */
  char *config[NUM_OPTIONS];     /* Civetweb configuration parameters */
  struct mg_callbacks callbacks; /* User-defined callback function */
  void *user_data;               /* User-defined data */
  int context_type;              /* 1 = server context, 2 = client context */

  struct socket *listening_sockets;
  in_port_t *listening_ports;
  unsigned int num_listening_sockets;

  volatile int
    running_worker_threads; /* Number of currently running worker threads */
  pthread_mutex_t thread_mutex; /* Protects (max|num)_threads */
  pthread_cond_t thread_cond; /* Condvar for tracking workers terminations */

  struct socket queue[MGSQLEN]; /* Accepted sockets */
  volatile int sq_head;         /* Head of the socket queue */
  volatile int sq_tail;         /* Tail of the socket queue */
  pthread_cond_t sq_full;       /* Signaled when socket is produced */
  pthread_cond_t sq_empty;      /* Signaled when socket is consumed */
  pthread_t masterthreadid;     /* The master thread ID */
  unsigned int
    cfg_worker_threads;     /* The number of configured worker threads. */
  pthread_t *workerthreadids; /* The worker thread IDs */

  time_t start_time;        /* Server start time, used for authentication */
  uint64_t auth_nonce_mask; /* Mask for all nonce values */
  pthread_mutex_t nonce_mutex; /* Protects nonce_count */
  unsigned long nonce_count;   /* Used nonces, used for authentication */

  char *systemName; /* What operating system is running */

                    /* linked list of uri handlers */
  struct mg_handler_info *handlers;

#if defined(USE_LUA) && defined(USE_WEBSOCKET)
  /* linked list of shared lua websockets */
  struct mg_shared_lua_websocket_list *shared_lua_websockets;
#endif

#ifdef USE_TIMERS
  struct ttimers *timers;
#endif
};

struct mg_connection {
  struct mg_request_info request_info;
  struct mg_context *ctx;
  SSL *ssl;                 /* SSL descriptor */
  SSL_CTX *client_ssl_ctx;  /* SSL context for client connections */
  struct socket client;     /* Connected client */
  time_t conn_birth_time;   /* Time (wall clock) when connection was
                            * established */
  struct timespec req_time; /* Time (since system start) when the request
                            * was received */
  int64_t num_bytes_sent;   /* Total bytes sent to client */
  int64_t content_len;      /* Content-Length header value */
  int64_t consumed_content; /* How many bytes of content have been read */
  int is_chunked;           /* Transfer-Encoding is chunked: 0=no, 1=yes:
                            * data available, 2: all data read */
  size_t chunk_remainder;   /* Unread data from the last chunk */
  char *buf;                /* Buffer for received data */
  char *path_info;          /* PATH_INFO part of the URL */

  int must_close;       /* 1 if connection must be closed */
  int in_error_handler; /* 1 if in handler for user defined error
                        * pages */
  int internal_error;   /* 1 if an error occured while processing the
                        * request */

  int buf_size;                /* Buffer size */
  int request_len;             /* Size of the request + headers in a buffer */
  int data_len;                /* Total size of data in a buffer */
  int status_code;             /* HTTP reply status code, e.g. 200 */
  int throttle;                /* Throttling, bytes/sec. <= 0 means no
                               * throttle */
  time_t last_throttle_time;   /* Last time throttled data was sent */
  int64_t last_throttle_bytes; /* Bytes sent this second */
  pthread_mutex_t mutex;       /* Used by mg_(un)lock_connection to ensure
                               * atomic transmissions for websockets */
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
  void *lua_websocket_state; /* Lua_State for a websocket connection */
#endif
};


static pthread_key_t sTlsKey; /* Thread local storage index */
static int sTlsInit = 0;
static int thread_idx_max = 0;


struct mg_workerTLS {
  int is_master;
  unsigned long thread_idx;
#if defined(_WIN32) && !defined(__SYMBIAN32__)
  HANDLE pthread_cond_helper_mutex;
#endif
};

/* Directory entry */
struct de {
  struct mg_connection *conn;
  char *file_name;
  struct file file;
};


#if defined(USE_WEBSOCKET)
static int is_websocket_protocol(const struct mg_connection *conn);
#else
#define is_websocket_protocol(conn) (0)
#endif


static int
mg_atomic_inc(volatile int *addr)
{
  int ret;
#if defined(_WIN32) && !defined(__SYMBIAN32__)
  /* Depending on the SDK, this function uses either
  * (volatile unsigned int *) or (volatile LONG *),
  * so whatever you use, the other SDK is likely to raise a warning. */
  ret = InterlockedIncrement((volatile long *)addr);
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))
  ret = __sync_add_and_fetch(addr, 1);
#else
  ret = (++(*addr));
#endif
  return ret;
}


static int
mg_atomic_dec(volatile int *addr)
{
  int ret;
#if defined(_WIN32) && !defined(__SYMBIAN32__)
  /* Depending on the SDK, this function uses either
  * (volatile unsigned int *) or (volatile LONG *),
  * so whatever you use, the other SDK is likely to raise a warning. */
  ret = InterlockedDecrement((volatile long *)addr);
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))
  ret = __sync_sub_and_fetch(addr, 1);
#else
  ret = (--(*addr));
#endif
  return ret;
}

#if !defined(NO_THREAD_NAME)
#if defined(_WIN32) && defined(_MSC_VER)
/* Set the thread name for debugging purposes in Visual Studio
* http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx
*/
#pragma pack(push, 8)
typedef struct tagTHREADNAME_INFO {
  DWORD dwType;     /* Must be 0x1000. */
  LPCSTR szName;    /* Pointer to name (in user addr space). */
  DWORD dwThreadID; /* Thread ID (-1=caller thread). */
  DWORD dwFlags;    /* Reserved for future use, must be zero. */
} THREADNAME_INFO;
#pragma pack(pop)
#elif defined(__linux__)
#include <sys/prctl.h>
#include <sys/sendfile.h>
#endif


static void
mg_set_thread_name(const char *name)
{
  char threadName[16 + 1]; /* 16 = Max. thread length in Linux/OSX/.. */

  mg_snprintf(
    NULL, NULL, threadName, sizeof(threadName), "civetweb-%s", name);

#if defined(_WIN32)
#if defined(_MSC_VER)
  /* Windows and Visual Studio Compiler */
  __try
  {
    THREADNAME_INFO info;
    info.dwType = 0x1000;
    info.szName = threadName;
    info.dwThreadID = ~0U;
    info.dwFlags = 0;

    RaiseException(0x406D1388,
      0,
      sizeof(info) / sizeof(ULONG_PTR),
      (ULONG_PTR *)&info);
  }
  __except (EXCEPTION_EXECUTE_HANDLER)
  {
  }
#elif defined(__MINGW32__)
  /* No option known to set thread name for MinGW */
#endif
#elif defined(__GLIBC__)                                                       \
    && ((__GLIBC__ > 2) || ((__GLIBC__ == 2) && (__GLIBC_MINOR__ >= 12)))
  /* pthread_setname_np first appeared in glibc in version 2.12*/
  (void)pthread_setname_np(pthread_self(), threadName);
#elif defined(__linux__)
  /* on linux we can use the old prctl function */
  (void)prctl(PR_SET_NAME, threadName, 0, 0, 0);
#endif
}
#else /* !defined(NO_THREAD_NAME) */
void
mg_set_thread_name(const char *threadName)
{
}
#endif


#if defined(MG_LEGACY_INTERFACE)
const char **
mg_get_valid_option_names(void)
{
  /* This function is deprecated. Use mg_get_valid_options instead. */
  static const char *
    data[2 * sizeof(config_options) / sizeof(config_options[0])] = { 0 };
  int i;

  for (i = 0; config_options[i].name != NULL; i++) {
    data[i * 2] = config_options[i].name;
    data[i * 2 + 1] = config_options[i].default_value;
  }

  return data;
}
#endif


const struct mg_option *
mg_get_valid_options(void)
{
  return config_options;
}


static int
is_file_in_memory(const struct mg_connection *conn,
  const char *path,
struct file *filep)
{
  size_t size = 0;
  if (!conn || !filep) {
    return 0;
  }

  if (conn->ctx->callbacks.open_file) {
    filep->membuf = conn->ctx->callbacks.open_file(conn, path, &size);
    if (filep->membuf != NULL) {
      /* NOTE: override filep->size only on success. Otherwise, it might
      * break constructs like if (!mg_stat() || !mg_fopen()) ... */
      filep->size = size;
    }
  }

  return filep->membuf != NULL;
}


static int
is_file_opened(const struct file *filep)
{
  if (!filep) {
    return 0;
  }

  return filep->membuf != NULL || filep->fp != NULL;
}


static int
mg_fopen(const struct mg_connection *conn,
  const char *path,
  const char *mode,
struct file *filep)
{
  struct stat st;

  if (!filep) {
    return 0;
  }

  /* TODO (high): mg_fopen should only open a file, while mg_stat should
  * only get the file status. They should not work on different members of
  * the same structure (bad cohesion). */
  memset(filep, 0, sizeof(*filep));

  if (stat(path, &st) == 0) {
    filep->size = (uint64_t)(st.st_size);
  }

  if (!is_file_in_memory(conn, path, filep)) {
#ifdef _WIN32
    wchar_t wbuf[PATH_MAX], wmode[20];
    to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
    MultiByteToWideChar(CP_UTF8, 0, mode, -1, wmode, ARRAY_SIZE(wmode));
    filep->fp = _wfopen(wbuf, wmode);
#else
    /* Linux et al already use unicode. No need to convert. */
    filep->fp = fopen(path, mode);
#endif
  }

  return is_file_opened(filep);
}


static void
mg_fclose(struct file *filep)
{
  if (filep != NULL && filep->fp != NULL) {
    fclose(filep->fp);
  }
}


static void
mg_strlcpy(register char *dst, register const char *src, size_t n)
{
  for (; *src != '\0' && n > 1; n--) {
    *dst++ = *src++;
  }
  *dst = '\0';
}


static int
lowercase(const char *s)
{
  return tolower(*(const unsigned char *)s);
}


int
mg_strncasecmp(const char *s1, const char *s2, size_t len)
{
  int diff = 0;

  if (len > 0) {
    do {
      diff = lowercase(s1++) - lowercase(s2++);
    } while (diff == 0 && s1[-1] != '\0' && --len > 0);
  }

  return diff;
}


static int
mg_strcasecmp(const char *s1, const char *s2)
{
  int diff;

  do {
    diff = lowercase(s1++) - lowercase(s2++);
  } while (diff == 0 && s1[-1] != '\0');

  return diff;
}


static char *
mg_strndup(const char *ptr, size_t len)
{
  char *p;

  if ((p = (char *)mg_malloc(len + 1)) != NULL) {
    mg_strlcpy(p, ptr, len + 1);
  }

  return p;
}


static char *
mg_strdup(const char *str)
{
  return mg_strndup(str, strlen(str));
}


static const char *
mg_strcasestr(const char *big_str, const char *small_str)
{
  size_t i, big_len = strlen(big_str), small_len = strlen(small_str);

  if (big_len >= small_len) {
    for (i = 0; i <= (big_len - small_len); i++) {
      if (mg_strncasecmp(big_str + i, small_str, small_len) == 0) {
        return big_str + i;
      }
    }
  }

  return NULL;
}


/* Return null terminated string of given maximum length.
* Report errors if length is exceeded. */
static void
mg_vsnprintf(const struct mg_connection *conn,
  int *truncated,
  char *buf,
  size_t buflen,
  const char *fmt,
  va_list ap)
{
  int n, ok;

  if (buflen == 0) {
    return;
  }

#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wformat-nonliteral"
  /* Using fmt as a non-literal is intended here, since it is mostly called
  * indirectly by mg_snprintf */
#endif

  n = (int)vsnprintf_impl(buf, buflen, fmt, ap);
  ok = (n >= 0) && ((size_t)n < buflen);

#ifdef __clang__
#pragma clang diagnostic pop
#endif

  if (ok) {
    if (truncated) {
      *truncated = 0;
    }
  }
  else {
    if (truncated) {
      *truncated = 1;
    }
    mg_cry(conn,
      "truncating vsnprintf buffer: [%.*s]",
      (int)((buflen > 200) ? 200 : (buflen - 1)),
      buf);
    n = (int)buflen - 1;
  }
  buf[n] = '\0';
}


static void
mg_snprintf(const struct mg_connection *conn,
  int *truncated,
  char *buf,
  size_t buflen,
  const char *fmt,
  ...)
{
  va_list ap;

  va_start(ap, fmt);
  mg_vsnprintf(conn, truncated, buf, buflen, fmt, ap);
  va_end(ap);
}


static int
get_option_index(const char *name)
{
  int i;

  for (i = 0; config_options[i].name != NULL; i++) {
    if (strcmp(config_options[i].name, name) == 0) {
      return i;
    }
  }
  return -1;
}


const char *
mg_get_option(const struct mg_context *ctx, const char *name)
{
  int i;
  if ((i = get_option_index(name)) == -1) {
    return NULL;
  }
  else if (!ctx || ctx->config[i] == NULL) {
    return "";
  }
  else {
    return ctx->config[i];
  }
}


struct mg_context *
  mg_get_context(const struct mg_connection *conn)
{
  return (conn == NULL) ? (struct mg_context *)NULL : (conn->ctx);
}


void *
mg_get_user_data(const struct mg_context *ctx)
{
  return (ctx == NULL) ? NULL : ctx->user_data;
}


void
mg_set_user_connection_data(const struct mg_connection *conn, void *data)
{
  if (conn != NULL) {
    ((struct mg_connection *)conn)->request_info.conn_data = data;
  }
}


void *
mg_get_user_connection_data(const struct mg_connection *conn)
{
  if (conn != NULL) {
    return conn->request_info.conn_data;
  }
  return NULL;
}


size_t
mg_get_ports(const struct mg_context *ctx, size_t size, int *ports, int *ssl)
{
  size_t i;
  if (!ctx) {
    return 0;
  }
  for (i = 0; i < size && i < ctx->num_listening_sockets; i++) {
    ssl[i] = ctx->listening_sockets[i].is_ssl;
    ports[i] = ctx->listening_ports[i];
  }
  return i;
}


int
mg_get_server_ports(const struct mg_context *ctx,
  int size,
struct mg_server_ports *ports)
{
  int i, cnt = 0;

  if (size <= 0) {
    return -1;
  }
  memset(ports, 0, sizeof(*ports) * (size_t)size);
  if (!ctx) {
    return -1;
  }
  if (!ctx->listening_sockets || !ctx->listening_ports) {
    return -1;
  }

  for (i = 0; (i < size) && (i < (int)ctx->num_listening_sockets); i++) {

    ports[cnt].port = ctx->listening_ports[i];
    ports[cnt].is_ssl = ctx->listening_sockets[i].is_ssl;
    ports[cnt].is_redirect = ctx->listening_sockets[i].ssl_redir;

    if (ctx->listening_sockets[i].lsa.sa.sa_family == AF_INET) {
      /* IPv4 */
      ports[cnt].protocol = 1;
      cnt++;
    }
    else if (ctx->listening_sockets[i].lsa.sa.sa_family == AF_INET6) {
      /* IPv6 */
      ports[cnt].protocol = 3;
      cnt++;
    }
  }

  return cnt;
}


static void
sockaddr_to_string(char *buf, size_t len, const union usa *usa)
{
  buf[0] = '\0';

  if (!usa) {
    return;
  }

  if (usa->sa.sa_family == AF_INET) {
    getnameinfo(&usa->sa,
      sizeof(usa->sin),
      buf,
      (unsigned)len,
      NULL,
      0,
      NI_NUMERICHOST);
  }
#if defined(USE_IPV6)
  else if (usa->sa.sa_family == AF_INET6) {
    getnameinfo(&usa->sa,
      sizeof(usa->sin6),
      buf,
      (unsigned)len,
      NULL,
      0,
      NI_NUMERICHOST);
  }
#endif
}


/* Convert time_t to a string. According to RFC2616, Sec 14.18, this must be
* included in all responses other than 100, 101, 5xx. */
static void
gmt_time_string(char *buf, size_t buf_len, time_t *t)
{
  struct tm *tm;

  tm = gmtime(t);
  if (tm != NULL) {
    strftime(buf, buf_len, "%a, %d %b %Y %H:%M:%S GMT", tm);
  }
  else {
    mg_strlcpy(buf, "Thu, 01 Jan 1970 00:00:00 GMT", buf_len);
    buf[buf_len - 1] = '\0';
  }
}


/* difftime for struct timespec. Return value is in seconds. */
static double
mg_difftimespec(const struct timespec *ts_now, const struct timespec *ts_before)
{
  return (double)(ts_now->tv_nsec - ts_before->tv_nsec) * 1.0E-9
    + (double)(ts_now->tv_sec - ts_before->tv_sec);
}


/* Print error message to the opened error log stream. */
void
mg_cry(const struct mg_connection *conn, const char *fmt, ...)
{
  char buf[MG_BUF_LEN], src_addr[IP_ADDR_STR_LEN];
  va_list ap;
  struct file fi;
  time_t timestamp;

  va_start(ap, fmt);
  IGNORE_UNUSED_RESULT(vsnprintf_impl(buf, sizeof(buf), fmt, ap));
  va_end(ap);
  buf[sizeof(buf) - 1] = 0;

  if (!conn) {
    puts(buf);
    return;
  }

  /* Do not lock when getting the callback value, here and below.
  * I suppose this is fine, since function cannot disappear in the
  * same way string option can. */
  if ((conn->ctx->callbacks.log_message == NULL)
    || (conn->ctx->callbacks.log_message(conn, buf) == 0)) {

    if (conn->ctx->config[ERROR_LOG_FILE] != NULL) {
      if (mg_fopen(conn, conn->ctx->config[ERROR_LOG_FILE], "a+", &fi)
        == 0) {
        fi.fp = NULL;
      }
    }
    else {
      fi.fp = NULL;
    }

    if (fi.fp != NULL) {
      flockfile(fi.fp);
      timestamp = time(NULL);

      sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
      fprintf(fi.fp,
        "[%010lu] [error] [client %s] ",
        (unsigned long)timestamp,
        src_addr);

      if (conn->request_info.request_method != NULL) {
        fprintf(fi.fp,
          "%s %s: ",
          conn->request_info.request_method,
          conn->request_info.request_uri);
      }

      fprintf(fi.fp, "%s", buf);
      fputc('\n', fi.fp);
      fflush(fi.fp);
      funlockfile(fi.fp);
      mg_fclose(&fi);
    }
  }
}


/* Return fake connection structure. Used for logging, if connection
* is not applicable at the moment of logging. */
static struct mg_connection *
fc(struct mg_context *ctx)
{
  static struct mg_connection fake_connection;
  fake_connection.ctx = ctx;
  return &fake_connection;
}


const char *
mg_version(void)
{
  return CIVETWEB_VERSION;
}


const struct mg_request_info *
mg_get_request_info(const struct mg_connection *conn)
{
  if (!conn) {
    return NULL;
  }
  return &conn->request_info;
}


/* Skip the characters until one of the delimiters characters found.
* 0-terminate resulting word. Skip the delimiter and following whitespaces.
* Advance pointer to buffer to the next word. Return found 0-terminated word.
* Delimiters can be quoted with quotechar. */
static char *
skip_quoted(char **buf,
  const char *delimiters,
  const char *whitespace,
  char quotechar)
{
  char *p, *begin_word, *end_word, *end_whitespace;

  begin_word = *buf;
  end_word = begin_word + strcspn(begin_word, delimiters);

  /* Check for quotechar */
  if (end_word > begin_word) {
    p = end_word - 1;
    while (*p == quotechar) {
      /* While the delimiter is quoted, look for the next delimiter. */
      /* This happens, e.g., in calls from parse_auth_header,
      * if the user name contains a " character. */

      /* If there is anything beyond end_word, copy it. */
      if (*end_word != '\0') {
        size_t end_off = strcspn(end_word + 1, delimiters);
        memmove(p, end_word, end_off + 1);
        p += end_off; /* p must correspond to end_word - 1 */
        end_word += end_off + 1;
      }
      else {
        *p = '\0';
        break;
      }
    }
    for (p++; p < end_word; p++) {
      *p = '\0';
    }
  }

  if (*end_word == '\0') {
    *buf = end_word;
  }
  else {
    end_whitespace = end_word + 1 + strspn(end_word + 1, whitespace);

    for (p = end_word; p < end_whitespace; p++) {
      *p = '\0';
    }

    *buf = end_whitespace;
  }

  return begin_word;
}


/* Simplified version of skip_quoted without quote char
* and whitespace == delimiters */
static char *
skip(char **buf, const char *delimiters)
{
  return skip_quoted(buf, delimiters, delimiters, 0);
}


/* Return HTTP header value, or NULL if not found. */
static const char *
get_header(const struct mg_request_info *ri, const char *name)
{
  int i;
  if (ri) {
    for (i = 0; i < ri->num_headers; i++) {
      if (!mg_strcasecmp(name, ri->http_headers[i].name)) {
        return ri->http_headers[i].value;
      }
    }
  }

  return NULL;
}


const char *
mg_get_header(const struct mg_connection *conn, const char *name)
{
  if (!conn) {
    return NULL;
  }

  return get_header(&conn->request_info, name);
}


/* A helper function for traversing a comma separated list of values.
* It returns a list pointer shifted to the next value, or NULL if the end
* of the list found.
* Value is stored in val vector. If value has form "x=y", then eq_val
* vector is initialized to point to the "y" part, and val vector length
* is adjusted to point only to "x". */
static const char *
next_option(const char *list, struct vec *val, struct vec *eq_val)
{
  if (val == NULL || list == NULL || *list == '\0') {
    /* End of the list */
    list = NULL;
  }
  else {
    val->ptr = list;
    if ((list = strchr(val->ptr, ',')) != NULL) {
      /* Comma found. Store length and shift the list ptr */
      val->len = ((size_t)(list - val->ptr));
      list++;
    }
    else {
      /* This value is the last one */
      list = val->ptr + strlen(val->ptr);
      val->len = ((size_t)(list - val->ptr));
    }

    if (eq_val != NULL) {
      /* Value has form "x=y", adjust pointers and lengths
      * so that val points to "x", and eq_val points to "y". */
      eq_val->len = 0;
      eq_val->ptr = (const char *)memchr(val->ptr, '=', val->len);
      if (eq_val->ptr != NULL) {
        eq_val->ptr++; /* Skip over '=' character */
        eq_val->len = ((size_t)(val->ptr - eq_val->ptr)) + val->len;
        val->len = ((size_t)(eq_val->ptr - val->ptr)) - 1;
      }
    }
  }

  return list;
}


/* Perform case-insensitive match of string against pattern */
static int
match_prefix(const char *pattern, size_t pattern_len, const char *str)
{
  const char *or_str;
  size_t i;
  int j, len, res;

  if ((or_str = (const char *)memchr(pattern, '|', pattern_len)) != NULL) {
    res = match_prefix(pattern, (size_t)(or_str - pattern), str);
    return res > 0 ? res : match_prefix(or_str + 1,
      (size_t)((pattern + pattern_len)
        - (or_str + 1)),
      str);
  }

  for (i = 0, j = 0; i < pattern_len; i++, j++) {
    if (pattern[i] == '?' && str[j] != '\0') {
      continue;
    }
    else if (pattern[i] == '$') {
      return str[j] == '\0' ? j : -1;
    }
    else if (pattern[i] == '*') {
      i++;
      if (pattern[i] == '*') {
        i++;
        len = (int)strlen(str + j);
      }
      else {
        len = (int)strcspn(str + j, "/");
      }
      if (i == pattern_len) {
        return j + len;
      }
      do {
        res = match_prefix(pattern + i, pattern_len - i, str + j + len);
      } while (res == -1 && len-- > 0);
      return res == -1 ? -1 : j + res + len;
    }
    else if (lowercase(&pattern[i]) != lowercase(&str[j])) {
      return -1;
    }
  }
  return j;
}


/* HTTP 1.1 assumes keep alive if "Connection:" header is not set
* This function must tolerate situations when connection info is not
* set up, for example if request parsing failed. */
static int
should_keep_alive(const struct mg_connection *conn)
{
  if (conn != NULL) {
    const char *http_version = conn->request_info.http_version;
    const char *header = mg_get_header(conn, "Connection");
    if (conn->must_close || conn->internal_error || conn->status_code == 401
      || mg_strcasecmp(conn->ctx->config[ENABLE_KEEP_ALIVE], "yes") != 0
      || (header != NULL && mg_strcasecmp(header, "keep-alive") != 0)
      || (header == NULL && http_version
        && 0 != strcmp(http_version, "1.1"))) {
      return 0;
    }
    return 1;
  }
  return 0;
}


static int
should_decode_url(const struct mg_connection *conn)
{
  if (!conn || !conn->ctx) {
    return 0;
  }

  return (mg_strcasecmp(conn->ctx->config[DECODE_URL], "yes") == 0);
}


static const char *
suggest_connection_header(const struct mg_connection *conn)
{
  return should_keep_alive(conn) ? "keep-alive" : "close";
}


static int
send_no_cache_header(struct mg_connection *conn)
{
  /* Send all current and obsolete cache opt-out directives. */
  return mg_printf(conn,
    "Cache-Control: no-cache, no-store, "
    "must-revalidate, private, max-age=0\r\n"
    "Pragma: no-cache\r\n"
    "Expires: 0\r\n");
}


static int
send_static_cache_header(struct mg_connection *conn)
{
  /* Read the server config to check how long a file may be cached.
  * The configuration is in seconds. */
  int max_age = atoi(conn->ctx->config[STATIC_FILE_MAX_AGE]);
  if (max_age <= 0) {
    /* 0 means "do not cache". All values <0 are reserved
    * and may be used differently in the future. */
    /* If a file should not be cached, do not only send
    * max-age=0, but also pragmas and Expires headers. */
    return send_no_cache_header(conn);
  }

  /* Use "Cache-Control: max-age" instead of "Expires" header.
  * Reason: see https://www.mnot.net/blog/2007/05/15/expires_max-age */
  /* See also https://www.mnot.net/cache_docs/ */
  return mg_printf(conn, "Cache-Control: max-age=%u\r\n", (unsigned)max_age);
}


static void handle_file_based_request(struct mg_connection *conn,
  const char *path,
struct file *filep);

static int
mg_stat(struct mg_connection *conn, const char *path, struct file *filep);


static const char *
mg_get_response_code_text(int response_code, struct mg_connection *conn)
{
  /* See IANA HTTP status code assignment:
  * http://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml
  */

  switch (response_code) {
    /* RFC2616 Section 10.1 - Informational 1xx */
  case 100:
    return "Continue"; /* RFC2616 Section 10.1.1 */
  case 101:
    return "Switching Protocols"; /* RFC2616 Section 10.1.2 */
  case 102:
    return "Processing"; /* RFC2518 Section 10.1 */

                         /* RFC2616 Section 10.2 - Successful 2xx */
  case 200:
    return "OK"; /* RFC2616 Section 10.2.1 */
  case 201:
    return "Created"; /* RFC2616 Section 10.2.2 */
  case 202:
    return "Accepted"; /* RFC2616 Section 10.2.3 */
  case 203:
    return "Non-Authoritative Information"; /* RFC2616 Section 10.2.4 */
  case 204:
    return "No Content"; /* RFC2616 Section 10.2.5 */
  case 205:
    return "Reset Content"; /* RFC2616 Section 10.2.6 */
  case 206:
    return "Partial Content"; /* RFC2616 Section 10.2.7 */
  case 207:
    return "Multi-Status"; /* RFC2518 Section 10.2, RFC4918 Section 11.1 */
  case 208:
    return "Already Reported"; /* RFC5842 Section 7.1 */

  case 226:
    return "IM used"; /* RFC3229 Section 10.4.1 */

                      /* RFC2616 Section 10.3 - Redirection 3xx */
  case 300:
    return "Multiple Choices"; /* RFC2616 Section 10.3.1 */
  case 301:
    return "Moved Permanently"; /* RFC2616 Section 10.3.2 */
  case 302:
    return "Found"; /* RFC2616 Section 10.3.3 */
  case 303:
    return "See Other"; /* RFC2616 Section 10.3.4 */
  case 304:
    return "Not Modified"; /* RFC2616 Section 10.3.5 */
  case 305:
    return "Use Proxy"; /* RFC2616 Section 10.3.6 */
  case 307:
    return "Temporary Redirect"; /* RFC2616 Section 10.3.8 */
  case 308:
    return "Permanent Redirect"; /* RFC7238 Section 3 */

                                 /* RFC2616 Section 10.4 - Client Error 4xx */
  case 400:
    return "Bad Request"; /* RFC2616 Section 10.4.1 */
  case 401:
    return "Unauthorized"; /* RFC2616 Section 10.4.2 */
  case 402:
    return "Payment Required"; /* RFC2616 Section 10.4.3 */
  case 403:
    return "Forbidden"; /* RFC2616 Section 10.4.4 */
  case 404:
    return "Not Found"; /* RFC2616 Section 10.4.5 */
  case 405:
    return "Method Not Allowed"; /* RFC2616 Section 10.4.6 */
  case 406:
    return "Not Acceptable"; /* RFC2616 Section 10.4.7 */
  case 407:
    return "Proxy Authentication Required"; /* RFC2616 Section 10.4.8 */
  case 408:
    return "Request Time-out"; /* RFC2616 Section 10.4.9 */
  case 409:
    return "Conflict"; /* RFC2616 Section 10.4.10 */
  case 410:
    return "Gone"; /* RFC2616 Section 10.4.11 */
  case 411:
    return "Length Required"; /* RFC2616 Section 10.4.12 */
  case 412:
    return "Precondition Failed"; /* RFC2616 Section 10.4.13 */
  case 413:
    return "Request Entity Too Large"; /* RFC2616 Section 10.4.14 */
  case 414:
    return "Request-URI Too Large"; /* RFC2616 Section 10.4.15 */
  case 415:
    return "Unsupported Media Type"; /* RFC2616 Section 10.4.16 */
  case 416:
    return "Requested range not satisfiable"; /* RFC2616 Section 10.4.17 */
  case 417:
    return "Expectation Failed"; /* RFC2616 Section 10.4.18 */

  case 421:
    return "Misdirected Request"; /* RFC7540 Section 9.1.2 */
  case 422:
    return "Unproccessable entity"; /* RFC2518 Section 10.3, RFC4918
                                    * Section 11.2 */
  case 423:
    return "Locked"; /* RFC2518 Section 10.4, RFC4918 Section 11.3 */
  case 424:
    return "Failed Dependency"; /* RFC2518 Section 10.5, RFC4918
                                * Section 11.4 */

  case 426:
    return "Upgrade Required"; /* RFC 2817 Section 4 */

  case 428:
    return "Precondition Required"; /* RFC 6585, Section 3 */
  case 429:
    return "Too Many Requests"; /* RFC 6585, Section 4 */

  case 431:
    return "Request Header Fields Too Large"; /* RFC 6585, Section 5 */

  case 451:
    return "Unavailable For Legal Reasons"; /* draft-tbray-http-legally-restricted-status-05,
                                            * Section 3 */

                                            /* RFC2616 Section 10.5 - Server Error 5xx */
  case 500:
    return "Internal Server Error"; /* RFC2616 Section 10.5.1 */
  case 501:
    return "Not Implemented"; /* RFC2616 Section 10.5.2 */
  case 502:
    return "Bad Gateway"; /* RFC2616 Section 10.5.3 */
  case 503:
    return "Service Unavailable"; /* RFC2616 Section 10.5.4 */
  case 504:
    return "Gateway Time-out"; /* RFC2616 Section 10.5.5 */
  case 505:
    return "HTTP Version not supported"; /* RFC2616 Section 10.5.6 */
  case 506:
    return "Variant Also Negotiates"; /* RFC 2295, Section 8.1 */
  case 507:
    return "Insufficient Storage"; /* RFC2518 Section 10.6, RFC4918
                                   * Section 11.5 */
  case 508:
    return "Loop Detected"; /* RFC5842 Section 7.1 */

  case 510:
    return "Not Extended"; /* RFC 2774, Section 7 */
  case 511:
    return "Network Authentication Required"; /* RFC 6585, Section 6 */

                                              /* Other status codes, not shown in the IANA HTTP status code assignment.
                                              * E.g., "de facto" standards due to common use, ... */
  case 418:
    return "I am a teapot"; /* RFC2324 Section 2.3.2 */
  case 419:
    return "Authentication Timeout"; /* common use */

  default:
    /* This error code is unknown. This should not happen. */
    if (conn) {
      mg_cry(conn, "Unknown HTTP response code: %u", response_code);
    }

    /* Return at least a category according to RFC 2616 Section 10. */
    if (response_code >= 100 && response_code < 200) {
      /* Unknown informational status code */
      return "Information";
    }
    if (response_code >= 200 && response_code < 300) {
      /* Unknown success code */
      return "Success";
    }
    if (response_code >= 300 && response_code < 400) {
      /* Unknown redirection code */
      return "Redirection";
    }
    if (response_code >= 400 && response_code < 500) {
      /* Unknown request error code */
      return "Client Error";
    }
    if (response_code >= 500 && response_code < 600) {
      /* Unknown server error code */
      return "Server Error";
    }

    /* Response code not even within reasonable range */
    return "";
  }
}


static void send_http_error(struct mg_connection *,
  int,
  PRINTF_FORMAT_STRING(const char *fmt),
  ...) PRINTF_ARGS(3, 4);

static void
send_http_error(struct mg_connection *conn, int status, const char *fmt, ...)
{
  char buf[MG_BUF_LEN];
  va_list ap;
  int len, i, page_handler_found, scope, truncated;
  char date[64];
  time_t curtime = time(NULL);
  const char *error_handler = NULL;
  struct file error_page_file = STRUCT_FILE_INITIALIZER;
  const char *error_page_file_ext, *tstr;

  const char *status_text = mg_get_response_code_text(status, conn);

  if (conn == NULL) {
    return;
  }

  conn->status_code = status;
  if (conn->in_error_handler || conn->ctx->callbacks.http_error == NULL
    || conn->ctx->callbacks.http_error(conn, status)) {
    if (!conn->in_error_handler) {
      /* Send user defined error pages, if defined */
      error_handler = conn->ctx->config[ERROR_PAGES];
      error_page_file_ext = conn->ctx->config[INDEX_FILES];
      page_handler_found = 0;
      if (error_handler != NULL) {
        for (scope = 1; (scope <= 3) && !page_handler_found; scope++) {
          switch (scope) {
          case 1: /* Handler for specific error, e.g. 404 error */
            mg_snprintf(conn,
              &truncated,
              buf,
              sizeof(buf) - 32,
              "%serror%03u.",
              error_handler,
              status);
            break;
          case 2: /* Handler for error group, e.g., 5xx error handler
                  * for all server errors (500-599) */
            mg_snprintf(conn,
              &truncated,
              buf,
              sizeof(buf) - 32,
              "%serror%01uxx.",
              error_handler,
              status / 100);
            break;
          default: /* Handler for all errors */
            mg_snprintf(conn,
              &truncated,
              buf,
              sizeof(buf) - 32,
              "%serror.",
              error_handler);
            break;
          }

          /* String truncation in buf may only occur if error_handler
          * is too long. This string is from the config, not from a
          * client. */
          (void)truncated;

          len = (int)strlen(buf);

          tstr = strchr(error_page_file_ext, '.');

          while (tstr) {
            for (i = 1; i < 32 && tstr[i] != 0 && tstr[i] != ',';
            i++)
              buf[len + i - 1] = tstr[i];
            buf[len + i - 1] = 0;
            if (mg_stat(conn, buf, &error_page_file)) {
              page_handler_found = 1;
              break;
            }
            tstr = strchr(tstr + i, '.');
          }
        }
      }

      if (page_handler_found) {
        conn->in_error_handler = 1;
        handle_file_based_request(conn, buf, &error_page_file);
        conn->in_error_handler = 0;
        return;
      }
    }

    /* No custom error page. Send default error page. */
    gmt_time_string(date, sizeof(date), &curtime);

    conn->must_close = 1;
    mg_printf(conn, "HTTP/1.1 %d %s\r\n", status, status_text);
    send_no_cache_header(conn);
    mg_printf(conn,
      "Date: %s\r\n"
      "Connection: close\r\n\r\n",
      date);

    /* Errors 1xx, 204 and 304 MUST NOT send a body */
    if (status > 199 && status != 204 && status != 304) {

      mg_printf(conn, "Error %d: %s\n", status, status_text);

      if (fmt != NULL) {
        va_start(ap, fmt);
        mg_vsnprintf(conn, NULL, buf, sizeof(buf), fmt, ap);
        va_end(ap);
        mg_write(conn, buf, strlen(buf));
        DEBUG_TRACE("Error %i - [%s]", status, buf);
      }

    }
    else {
      /* No body allowed. Close the connection. */
      DEBUG_TRACE("Error %i", status);
    }
  }
}

#if defined(_WIN32) && !defined(__SYMBIAN32__)
/* Create substitutes for POSIX functions in Win32. */

#if defined(__MINGW32__)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif


static int
pthread_mutex_init(pthread_mutex_t *mutex, void *unused)
{
  (void)unused;
  *mutex = CreateMutex(NULL, FALSE, NULL);
  return *mutex == NULL ? -1 : 0;
}


static int
pthread_mutex_destroy(pthread_mutex_t *mutex)
{
  return CloseHandle(*mutex) == 0 ? -1 : 0;
}


static int
pthread_mutex_lock(pthread_mutex_t *mutex)
{
  return WaitForSingleObject(*mutex, INFINITE) == WAIT_OBJECT_0 ? 0 : -1;
}


#ifdef ENABLE_UNUSED_PTHREAD_FUNCTIONS
static int
pthread_mutex_trylock(pthread_mutex_t *mutex)
{
  switch (WaitForSingleObject(*mutex, 0)) {
  case WAIT_OBJECT_0:
    return 0;
  case WAIT_TIMEOUT:
    return -2; /* EBUSY */
  }
  return -1;
}
#endif


static int
pthread_mutex_unlock(pthread_mutex_t *mutex)
{
  return ReleaseMutex(*mutex) == 0 ? -1 : 0;
}


#ifndef WIN_PTHREADS_TIME_H
static int
clock_gettime(clockid_t clk_id, struct timespec *tp)
{
  FILETIME ft;
  ULARGE_INTEGER li;
  BOOL ok = FALSE;
  double d;
  static double perfcnt_per_sec = 0.0;

  if (tp) {
    memset(tp, 0, sizeof(*tp));
    if (clk_id == CLOCK_REALTIME) {
      GetSystemTimeAsFileTime(&ft);
      li.LowPart = ft.dwLowDateTime;
      li.HighPart = ft.dwHighDateTime;
      li.QuadPart -= 116444736000000000; /* 1.1.1970 in filedate */
      tp->tv_sec = (time_t)(li.QuadPart / 10000000);
      tp->tv_nsec = (long)(li.QuadPart % 10000000) * 100;
      ok = TRUE;
    }
    else if (clk_id == CLOCK_MONOTONIC) {
      if (perfcnt_per_sec == 0.0) {
        QueryPerformanceFrequency((LARGE_INTEGER *)&li);
        perfcnt_per_sec = 1.0 / li.QuadPart;
      }
      if (perfcnt_per_sec != 0.0) {
        QueryPerformanceCounter((LARGE_INTEGER *)&li);
        d = li.QuadPart * perfcnt_per_sec;
        tp->tv_sec = (time_t)d;
        d -= tp->tv_sec;
        tp->tv_nsec = (long)(d * 1.0E9);
        ok = TRUE;
      }
    }
  }

  return ok ? 0 : -1;
}
#endif


static int
pthread_cond_init(pthread_cond_t *cv, const void *unused)
{
  (void)unused;
  InitializeCriticalSection(&cv->threadIdSec);
  cv->waitingthreadcount = 0;
  cv->waitingthreadhdls =
    (pthread_t *)mg_calloc(MAX_WORKER_THREADS, sizeof(pthread_t));
  return (cv->waitingthreadhdls != NULL) ? 0 : -1;
}


static int
pthread_cond_timedwait(pthread_cond_t *cv,
  pthread_mutex_t *mutex,
  const struct timespec *abstime)
{
  struct mg_workerTLS *tls =
    (struct mg_workerTLS *)pthread_getspecific(sTlsKey);
  int ok;
  struct timespec tsnow;
  int64_t nsnow, nswaitabs, nswaitrel;
  DWORD mswaitrel;

  EnterCriticalSection(&cv->threadIdSec);
  assert(cv->waitingthreadcount < MAX_WORKER_THREADS);
  cv->waitingthreadhdls[cv->waitingthreadcount] =
    tls->pthread_cond_helper_mutex;
  cv->waitingthreadcount++;
  LeaveCriticalSection(&cv->threadIdSec);

  if (abstime) {
    clock_gettime(CLOCK_REALTIME, &tsnow);
    nsnow = (((int64_t)tsnow.tv_sec) * 1000000000) + tsnow.tv_nsec;
    nswaitabs =
      (((int64_t)abstime->tv_sec) * 1000000000) + abstime->tv_nsec;
    nswaitrel = nswaitabs - nsnow;
    if (nswaitrel < 0) {
      nswaitrel = 0;
    }
    mswaitrel = (DWORD)(nswaitrel / 1000000);
  }
  else {
    mswaitrel = INFINITE;
  }

  pthread_mutex_unlock(mutex);
  ok = (WAIT_OBJECT_0
    == WaitForSingleObject(tls->pthread_cond_helper_mutex, mswaitrel));
  pthread_mutex_lock(mutex);

  return ok ? 0 : -1;
}


static int
pthread_cond_wait(pthread_cond_t *cv, pthread_mutex_t *mutex)
{
  return pthread_cond_timedwait(cv, mutex, NULL);
}


static int
pthread_cond_signal(pthread_cond_t *cv)
{
  int i;
  HANDLE wkup = NULL;
  BOOL ok = FALSE;

  EnterCriticalSection(&cv->threadIdSec);
  if (cv->waitingthreadcount) {
    wkup = cv->waitingthreadhdls[0];
    ok = SetEvent(wkup);

    for (i = 1; i < cv->waitingthreadcount; i++) {
      cv->waitingthreadhdls[i - 1] = cv->waitingthreadhdls[i];
    }
    cv->waitingthreadcount--;

    assert(ok);
  }
  LeaveCriticalSection(&cv->threadIdSec);

  return ok ? 0 : 1;
}


static int
pthread_cond_broadcast(pthread_cond_t *cv)
{
  EnterCriticalSection(&cv->threadIdSec);
  while (cv->waitingthreadcount) {
    pthread_cond_signal(cv);
  }
  LeaveCriticalSection(&cv->threadIdSec);

  return 0;
}


static int
pthread_cond_destroy(pthread_cond_t *cv)
{
  EnterCriticalSection(&cv->threadIdSec);
  assert(cv->waitingthreadcount == 0);
  mg_free(cv->waitingthreadhdls);
  cv->waitingthreadhdls = 0;
  LeaveCriticalSection(&cv->threadIdSec);
  DeleteCriticalSection(&cv->threadIdSec);

  return 0;
}


#if defined(__MINGW32__)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif


/* For Windows, change all slashes to backslashes in path names. */
static void
change_slashes_to_backslashes(char *path)
{
  int i;

  for (i = 0; path[i] != '\0'; i++) {
    if (path[i] == '/') {
      path[i] = '\\';
    }

    /* remove double backslash (check i > 0 to preserve UNC paths,
    * like \\server\file.txt) */
    if ((path[i] == '\\') && (i > 0)) {
      while (path[i + 1] == '\\' || path[i + 1] == '/') {
        (void)memmove(path + i + 1, path + i + 2, strlen(path + i + 1));
      }
    }
  }
}


/* Encode 'path' which is assumed UTF-8 string, into UNICODE string.
* wbuf and wbuf_len is a target buffer and its length. */
static void
to_unicode(const char *path, wchar_t *wbuf, size_t wbuf_len)
{
  char buf[PATH_MAX], buf2[PATH_MAX];

  mg_strlcpy(buf, path, sizeof(buf));
  change_slashes_to_backslashes(buf);

  /* Convert to Unicode and back. If doubly-converted string does not
  * match the original, something is fishy, reject. */
  memset(wbuf, 0, wbuf_len * sizeof(wchar_t));
  MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, (int)wbuf_len);
  WideCharToMultiByte(
    CP_UTF8, 0, wbuf, (int)wbuf_len, buf2, sizeof(buf2), NULL, NULL);
  if (strcmp(buf, buf2) != 0) {
    wbuf[0] = L'\0';
  }
}

#if defined(_WIN32_WCE)
/* Create substitutes for POSIX functions in Win32. */

#if defined(__MINGW32__)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif


static time_t
time(time_t *ptime)
{
  time_t t;
  SYSTEMTIME st;
  FILETIME ft;

  GetSystemTime(&st);
  SystemTimeToFileTime(&st, &ft);
  t = SYS2UNIX_TIME(ft.dwLowDateTime, ft.dwHighDateTime);

  if (ptime != NULL) {
    *ptime = t;
  }

  return t;
}


static struct tm *
localtime(const time_t *ptime, struct tm *ptm)
{
  int64_t t = ((int64_t)*ptime) * RATE_DIFF + EPOCH_DIFF;
  FILETIME ft, lft;
  SYSTEMTIME st;
  TIME_ZONE_INFORMATION tzinfo;

  if (ptm == NULL) {
    return NULL;
  }

  *(int64_t *)&ft = t;
  FileTimeToLocalFileTime(&ft, &lft);
  FileTimeToSystemTime(&lft, &st);
  ptm->tm_year = st.wYear - 1900;
  ptm->tm_mon = st.wMonth - 1;
  ptm->tm_wday = st.wDayOfWeek;
  ptm->tm_mday = st.wDay;
  ptm->tm_hour = st.wHour;
  ptm->tm_min = st.wMinute;
  ptm->tm_sec = st.wSecond;
  ptm->tm_yday = 0; /* hope nobody uses this */
  ptm->tm_isdst =
    GetTimeZoneInformation(&tzinfo) == TIME_ZONE_ID_DAYLIGHT ? 1 : 0;

  return ptm;
}


static struct tm *
gmtime(const time_t *ptime, struct tm *ptm)
{
  /* FIXME(lsm): fix this. */
  return localtime(ptime, ptm);
}


static size_t
strftime(char *dst, size_t dst_size, const char *fmt, const struct tm *tm)
{
  (void)mg_snprintf(NULL, dst, dst_size, "implement strftime() for WinCE");
  return 0;
}


#if defined(__MINGW32__)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif

#endif


/* Windows happily opens files with some garbage at the end of file name.
* For example, fopen("a.cgi    ", "r") on Windows successfully opens
* "a.cgi", despite one would expect an error back.
* This function returns non-0 if path ends with some garbage. */
static int
path_cannot_disclose_cgi(const char *path)
{
  static const char *allowed_last_characters = "_-";
  int last = path[strlen(path) - 1];
  return isalnum(last) || strchr(allowed_last_characters, last) != NULL;
}


static int
mg_stat(struct mg_connection *conn, const char *path, struct file *filep)
{
  wchar_t wbuf[PATH_MAX];
  WIN32_FILE_ATTRIBUTE_DATA info;
  time_t creation_time;

  if (!filep) {
    return 0;
  }
  memset(filep, 0, sizeof(*filep));

  if (conn && is_file_in_memory(conn, path, filep)) {
    /* filep->is_directory = 0; filep->gzipped = 0; .. already done by
    * memset */
    filep->last_modified = time(NULL);
    /* last_modified = now ... assumes the file may change during runtime,
    * so every mg_fopen call may return different data */
    /* last_modified = conn->ctx.start_time;
    * May be used it the data does not change during runtime. This allows
    * browser caching. Since we do not know, we have to assume the file
    * in memory may change. */
    return 1;
  }

  to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
  if (GetFileAttributesExW(wbuf, GetFileExInfoStandard, &info) != 0) {
    filep->size = MAKEUQUAD(info.nFileSizeLow, info.nFileSizeHigh);
    filep->last_modified =
      SYS2UNIX_TIME(info.ftLastWriteTime.dwLowDateTime,
        info.ftLastWriteTime.dwHighDateTime);

    /* On Windows, the file creation time can be higher than the
    * modification time, e.g. when a file is copied.
    * Since the Last-Modified timestamp is used for caching
    * it should be based on the most recent timestamp. */
    creation_time = SYS2UNIX_TIME(info.ftCreationTime.dwLowDateTime,
      info.ftCreationTime.dwHighDateTime);
    if (creation_time > filep->last_modified) {
      filep->last_modified = creation_time;
    }

    filep->is_directory = info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
    /* If file name is fishy, reset the file structure and return
    * error.
    * Note it is important to reset, not just return the error, cause
    * functions like is_file_opened() check the struct. */
    if (!filep->is_directory && !path_cannot_disclose_cgi(path)) {
      memset(filep, 0, sizeof(*filep));
      return 0;
    }

    return 1;
  }

  return 0;
}


static int
mg_remove(const char *path)
{
  wchar_t wbuf[PATH_MAX];
  to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
  return DeleteFileW(wbuf) ? 0 : -1;
}


static int
mg_mkdir(const char *path, int mode)
{
  char buf[PATH_MAX];
  wchar_t wbuf[PATH_MAX];

  (void)mode;
  mg_strlcpy(buf, path, sizeof(buf));
  change_slashes_to_backslashes(buf);

  (void)MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, ARRAY_SIZE(wbuf));

  return CreateDirectoryW(wbuf, NULL) ? 0 : -1;
}


/* Create substitutes for POSIX functions in Win32. */

#if defined(__MINGW32__)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif


/* Implementation of POSIX opendir/closedir/readdir for Windows. */
static DIR *
opendir(const char *name)
{
  DIR *dir = NULL;
  wchar_t wpath[PATH_MAX];
  DWORD attrs;

  if (name == NULL) {
    SetLastError(ERROR_BAD_ARGUMENTS);
  }
  else if ((dir = (DIR *)mg_malloc(sizeof(*dir))) == NULL) {
    SetLastError(ERROR_NOT_ENOUGH_MEMORY);
  }
  else {
    to_unicode(name, wpath, ARRAY_SIZE(wpath));
    attrs = GetFileAttributesW(wpath);
    if (attrs != 0xFFFFFFFF && ((attrs & FILE_ATTRIBUTE_DIRECTORY)
      == FILE_ATTRIBUTE_DIRECTORY)) {
      (void)wcscat(wpath, L"\\*");
      dir->handle = FindFirstFileW(wpath, &dir->info);
      dir->result.d_name[0] = '\0';
    }
    else {
      mg_free(dir);
      dir = NULL;
    }
  }

  return dir;
}


static int
closedir(DIR *dir)
{
  int result = 0;

  if (dir != NULL) {
    if (dir->handle != INVALID_HANDLE_VALUE)
      result = FindClose(dir->handle) ? 0 : -1;

    mg_free(dir);
  }
  else {
    result = -1;
    SetLastError(ERROR_BAD_ARGUMENTS);
  }

  return result;
}


static struct dirent *
readdir(DIR *dir)
{
  struct dirent *result = 0;

  if (dir) {
    if (dir->handle != INVALID_HANDLE_VALUE) {
      result = &dir->result;
      (void)WideCharToMultiByte(CP_UTF8,
        0,
        dir->info.cFileName,
        -1,
        result->d_name,
        sizeof(result->d_name),
        NULL,
        NULL);

      if (!FindNextFileW(dir->handle, &dir->info)) {
        (void)FindClose(dir->handle);
        dir->handle = INVALID_HANDLE_VALUE;
      }

    }
    else {
      SetLastError(ERROR_FILE_NOT_FOUND);
    }
  }
  else {
    SetLastError(ERROR_BAD_ARGUMENTS);
  }

  return result;
}


#ifndef HAVE_POLL
static int
poll(struct pollfd *pfd, unsigned int n, int milliseconds)
{
  struct timeval tv;
  fd_set set;
  unsigned int i;
  int result;
  SOCKET maxfd = 0;

  memset(&tv, 0, sizeof(tv));
  tv.tv_sec = milliseconds / 1000;
  tv.tv_usec = (milliseconds % 1000) * 1000;
  FD_ZERO(&set);

  for (i = 0; i < n; i++) {
    FD_SET((SOCKET)pfd[i].fd, &set);
    pfd[i].revents = 0;

    if (pfd[i].fd > maxfd) {
      maxfd = pfd[i].fd;
    }
  }

  if ((result = select((int)maxfd + 1, &set, NULL, NULL, &tv)) > 0) {
    for (i = 0; i < n; i++) {
      if (FD_ISSET(pfd[i].fd, &set)) {
        pfd[i].revents = POLLIN;
      }
    }
  }

  return result;
}
#endif /* HAVE_POLL */

#if defined(__MINGW32__)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif


static void
set_close_on_exec(SOCKET sock, struct mg_connection *conn /* may be null */)
{
  (void)conn; /* Unused. */
  (void)SetHandleInformation((HANDLE)(intptr_t)sock, HANDLE_FLAG_INHERIT, 0);
}


int
mg_start_thread(mg_thread_func_t f, void *p)
{
#if defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1)
  /* Compile-time option to control stack size, e.g. -DUSE_STACK_SIZE=16384
  */
  return ((_beginthread((void(__cdecl *)(void *))f, USE_STACK_SIZE, p)
    == ((uintptr_t)(-1L)))
    ? -1
    : 0);
#else
  return (
    (_beginthread((void(__cdecl *)(void *))f, 0, p) == ((uintptr_t)(-1L)))
    ? -1
    : 0);
#endif /* defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1) */
}


/* Start a thread storing the thread context. */
static int
mg_start_thread_with_id(unsigned(__stdcall *f)(void *),
  void *p,
  pthread_t *threadidptr)
{
  uintptr_t uip;
  HANDLE threadhandle;
  int result = -1;

  uip = _beginthreadex(NULL, 0, (unsigned(__stdcall *)(void *))f, p, 0, NULL);
  threadhandle = (HANDLE)uip;
  if ((uip != (uintptr_t)(-1L)) && (threadidptr != NULL)) {
    *threadidptr = threadhandle;
    result = 0;
  }

  return result;
}


/* Wait for a thread to finish. */
static int
mg_join_thread(pthread_t threadid)
{
  int result;
  DWORD dwevent;

  result = -1;
  dwevent = WaitForSingleObject(threadid, INFINITE);
  if (dwevent == WAIT_FAILED) {
    DEBUG_TRACE("WaitForSingleObject() failed, error %d", ERRNO);
  }
  else {
    if (dwevent == WAIT_OBJECT_0) {
      CloseHandle(threadid);
      result = 0;
    }
  }

  return result;
}

#if !defined(NO_SSL_DL)
/* Create substitutes for POSIX functions in Win32. */

#if defined(__MINGW32__)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif


static HANDLE
dlopen(const char *dll_name, int flags)
{
  wchar_t wbuf[PATH_MAX];
  (void)flags;
  to_unicode(dll_name, wbuf, ARRAY_SIZE(wbuf));
  return LoadLibraryW(wbuf);
}


static int
dlclose(void *handle)
{
  int result;

  if (FreeLibrary((HMODULE)handle) != 0) {
    result = 0;
  }
  else {
    result = -1;
  }

  return result;
}

#if defined(__MINGW32__)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif

#endif


#if !defined(NO_CGI)
#define SIGKILL (0)

static int
kill(pid_t pid, int sig_num)
{
  (void)TerminateProcess((HANDLE)pid, (UINT)sig_num);
  (void)CloseHandle((HANDLE)pid);
  return 0;
}


static void
trim_trailing_whitespaces(char *s)
{
  char *e = s + strlen(s) - 1;
  while (e > s && isspace(*(unsigned char *)e)) {
    *e-- = '\0';
  }
}


static pid_t
spawn_process(struct mg_connection *conn,
  const char *prog,
  char *envblk,
  char *envp[],
  int fdin,
  int fdout,
  int fderr,
  const char *dir)
{
  HANDLE me;
  char *p, *interp, full_interp[PATH_MAX], full_dir[PATH_MAX],
    cmdline[PATH_MAX], buf[PATH_MAX];
  int truncated;
  struct file file = STRUCT_FILE_INITIALIZER;
  STARTUPINFOA si;
  PROCESS_INFORMATION pi = { 0 };

  (void)envp;

  memset(&si, 0, sizeof(si));
  si.cb = sizeof(si);

  si.dwFlags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
  si.wShowWindow = SW_HIDE;

  me = GetCurrentProcess();
  DuplicateHandle(me,
    (HANDLE)_get_osfhandle(fdin),
    me,
    &si.hStdInput,
    0,
    TRUE,
    DUPLICATE_SAME_ACCESS);
  DuplicateHandle(me,
    (HANDLE)_get_osfhandle(fdout),
    me,
    &si.hStdOutput,
    0,
    TRUE,
    DUPLICATE_SAME_ACCESS);
  DuplicateHandle(me,
    (HANDLE)_get_osfhandle(fderr),
    me,
    &si.hStdError,
    0,
    TRUE,
    DUPLICATE_SAME_ACCESS);

  /* If CGI file is a script, try to read the interpreter line */
  interp = conn->ctx->config[CGI_INTERPRETER];
  if (interp == NULL) {
    buf[0] = buf[1] = '\0';

    /* Read the first line of the script into the buffer */
    mg_snprintf(
      conn, &truncated, cmdline, sizeof(cmdline), "%s/%s", dir, prog);

    if (truncated) {
      pi.hProcess = (pid_t)-1;
      goto spawn_cleanup;
    }

    if (mg_fopen(conn, cmdline, "r", &file)) {
      p = (char *)file.membuf;
      mg_fgets(buf, sizeof(buf), &file, &p);
      mg_fclose(&file);
      buf[sizeof(buf) - 1] = '\0';
    }

    if (buf[0] == '#' && buf[1] == '!') {
      trim_trailing_whitespaces(buf + 2);
    }
    else {
      buf[2] = '\0';
    }
    interp = buf + 2;
  }

  if (interp[0] != '\0') {
    GetFullPathNameA(interp, sizeof(full_interp), full_interp, NULL);
    interp = full_interp;
  }
  GetFullPathNameA(dir, sizeof(full_dir), full_dir, NULL);

  if (interp[0] != '\0') {
    mg_snprintf(conn,
      &truncated,
      cmdline,
      sizeof(cmdline),
      "\"%s\" \"%s\\%s\"",
      interp,
      full_dir,
      prog);
  }
  else {
    mg_snprintf(conn,
      &truncated,
      cmdline,
      sizeof(cmdline),
      "\"%s\\%s\"",
      full_dir,
      prog);
  }

  if (truncated) {
    pi.hProcess = (pid_t)-1;
    goto spawn_cleanup;
  }

  DEBUG_TRACE("Running [%s]", cmdline);
  if (CreateProcessA(NULL,
    cmdline,
    NULL,
    NULL,
    TRUE,
    CREATE_NEW_PROCESS_GROUP,
    envblk,
    NULL,
    &si,
    &pi) == 0) {
    mg_cry(
      conn, "%s: CreateProcess(%s): %ld", __func__, cmdline, (long)ERRNO);
    pi.hProcess = (pid_t)-1;
    /* goto spawn_cleanup; */
  }

spawn_cleanup:
  (void)CloseHandle(si.hStdOutput);
  (void)CloseHandle(si.hStdError);
  (void)CloseHandle(si.hStdInput);
  if (pi.hThread != NULL) {
    (void)CloseHandle(pi.hThread);
  }

  return (pid_t)pi.hProcess;
}
#endif /* !NO_CGI */


static int
set_non_blocking_mode(SOCKET sock)
{
  unsigned long on = 1;
  return ioctlsocket(sock, (long)FIONBIO, &on);
}

#else

static int
mg_stat(struct mg_connection *conn, const char *path, struct file *filep)
{
  struct stat st;
  if (!filep) {
    return 0;
  }
  memset(filep, 0, sizeof(*filep));

  if (conn && is_file_in_memory(conn, path, filep)) {
    return 1;
  }

  if (0 == stat(path, &st)) {
    filep->size = (uint64_t)(st.st_size);
    filep->last_modified = st.st_mtime;
    filep->is_directory = S_ISDIR(st.st_mode);
    return 1;
  }

  return 0;
}


static void
set_close_on_exec(SOCKET fd, struct mg_connection *conn /* may be null */)
{
  if (fcntl(fd, F_SETFD, FD_CLOEXEC) != 0) {
    if (conn) {
      mg_cry(conn,
        "%s: fcntl(F_SETFD FD_CLOEXEC) failed: %s",
        __func__,
        strerror(ERRNO));
    }
  }
}


int
mg_start_thread(mg_thread_func_t func, void *param)
{
  pthread_t thread_id;
  pthread_attr_t attr;
  int result;

  (void)pthread_attr_init(&attr);
  (void)pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);

#if defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1)
  /* Compile-time option to control stack size,
  * e.g. -DUSE_STACK_SIZE=16384 */
  (void)pthread_attr_setstacksize(&attr, USE_STACK_SIZE);
#endif /* defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1) */

  result = pthread_create(&thread_id, &attr, func, param);
  pthread_attr_destroy(&attr);

  return result;
}


/* Start a thread storing the thread context. */
static int
mg_start_thread_with_id(mg_thread_func_t func,
  void *param,
  pthread_t *threadidptr)
{
  pthread_t thread_id;
  pthread_attr_t attr;
  int result;

  (void)pthread_attr_init(&attr);

#if defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1)
  /* Compile-time option to control stack size,
  * e.g. -DUSE_STACK_SIZE=16384 */
  (void)pthread_attr_setstacksize(&attr, USE_STACK_SIZE);
#endif /* defined(USE_STACK_SIZE) && USE_STACK_SIZE > 1 */

  result = pthread_create(&thread_id, &attr, func, param);
  pthread_attr_destroy(&attr);
  if ((result == 0) && (threadidptr != NULL)) {
    *threadidptr = thread_id;
  }
  return result;
}


/* Wait for a thread to finish. */
static int
mg_join_thread(pthread_t threadid)
{
  int result;

  result = pthread_join(threadid, NULL);
  return result;
}


#ifndef NO_CGI
static pid_t
spawn_process(struct mg_connection *conn,
  const char *prog,
  char *envblk,
  char *envp[],
  int fdin,
  int fdout,
  int fderr,
  const char *dir)
{
  pid_t pid;
  const char *interp;

  (void)envblk;

  if (conn == NULL) {
    return 0;
  }

  if ((pid = fork()) == -1) {
    /* Parent */
    send_http_error(conn,
      500,
      "Error: Creating CGI process\nfork(): %s",
      strerror(ERRNO));
  }
  else if (pid == 0) {
    /* Child */
    if (chdir(dir) != 0) {
      mg_cry(conn, "%s: chdir(%s): %s", __func__, dir, strerror(ERRNO));
    }
    else if (dup2(fdin, 0) == -1) {
      mg_cry(
        conn, "%s: dup2(%d, 0): %s", __func__, fdin, strerror(ERRNO));
    }
    else if (dup2(fdout, 1) == -1) {
      mg_cry(
        conn, "%s: dup2(%d, 1): %s", __func__, fdout, strerror(ERRNO));
    }
    else if (dup2(fderr, 2) == -1) {
      mg_cry(
        conn, "%s: dup2(%d, 2): %s", __func__, fderr, strerror(ERRNO));
    }
    else {
      /* Keep stderr and stdout in two different pipes.
      * Stdout will be sent back to the client,
      * stderr should go into a server error log. */
      (void)close(fdin);
      (void)close(fdout);
      (void)close(fderr);

      /* After exec, all signal handlers are restored to their default
      * values, with one exception of SIGCHLD. According to
      * POSIX.1-2001 and Linux's implementation, SIGCHLD's handler will
      * leave unchanged after exec if it was set to be ignored. Restore
      * it to default action. */
      signal(SIGCHLD, SIG_DFL);

      interp = conn->ctx->config[CGI_INTERPRETER];
      if (interp == NULL) {
        (void)execle(prog, prog, NULL, envp);
        mg_cry(conn,
          "%s: execle(%s): %s",
          __func__,
          prog,
          strerror(ERRNO));
      }
      else {
        (void)execle(interp, interp, prog, NULL, envp);
        mg_cry(conn,
          "%s: execle(%s %s): %s",
          __func__,
          interp,
          prog,
          strerror(ERRNO));
      }
    }
    exit(EXIT_FAILURE);
  }

  return pid;
}
#endif /* !NO_CGI */


static int
set_non_blocking_mode(SOCKET sock)
{
  int flags;

  flags = fcntl(sock, F_GETFL, 0);
  (void)fcntl(sock, F_SETFL, flags | O_NONBLOCK);

  return 0;
}
#endif /* _WIN32 */
/* End of initial operating system specific define block. */


/* Get a random number (independent of C rand function) */
static uint64_t
get_random(void)
{
  static uint64_t lfsr = 0; /* Linear feedback shift register */
  static uint64_t lcg = 0;  /* Linear congruential generator */
  struct timespec now;

  memset(&now, 0, sizeof(now));
  clock_gettime(CLOCK_MONOTONIC, &now);

  if (lfsr == 0) {
    /* lfsr will be only 0 if has not been initialized,
    * so this code is called only once. */
    lfsr = (((uint64_t)now.tv_sec) << 21) ^ ((uint64_t)now.tv_nsec)
      ^ ((uint64_t)(ptrdiff_t)&now) ^ ((uint64_t)pthread_self())
      ^ (((uint64_t)time(NULL)) << 33);
    lcg = (((uint64_t)now.tv_sec) << 25) + (uint64_t)now.tv_nsec
      + (uint64_t)(ptrdiff_t)&now;
  }
  else {
    /* Get the next step of both random number generators. */
    lfsr = (lfsr >> 1)
      | ((((lfsr >> 0) ^ (lfsr >> 1) ^ (lfsr >> 3) ^ (lfsr >> 4)) & 1)
        << 63);
    lcg = lcg * 6364136223846793005 + 1442695040888963407;
  }

  /* Combining two pseudo-random number generators and a high resolution part
  * of the current server time will make it hard (impossible?) to guess the
  * next number. */
  return (lfsr ^ lcg ^ (uint64_t)now.tv_nsec);
}


/* Write data to the IO channel - opened file descriptor, socket or SSL
* descriptor. Return number of bytes written. */
static int
push(struct mg_context *ctx,
  FILE *fp,
  SOCKET sock,
  SSL *ssl,
  const char *buf,
  int len,
  double timeout)
{
  struct timespec start, now;
  int n, err;

#ifdef _WIN32
  typedef int len_t;
#else
  typedef size_t len_t;
#endif

  if (timeout > 0) {
    memset(&start, 0, sizeof(start));
    memset(&now, 0, sizeof(now));
    clock_gettime(CLOCK_MONOTONIC, &start);
  }

  if (ctx == NULL) {
    return -1;
  }

#ifdef NO_SSL
  if (ssl) {
    return -1;
  }
#endif

  do {

#ifndef NO_SSL
    if (ssl != NULL) {
      n = SSL_write(ssl, buf, len);
      if (n <= 0) {
        err = SSL_get_error(ssl, n);
        if ((err == 5 /* SSL_ERROR_SYSCALL */) && (n == -1)) {
          err = ERRNO;
        }
        else {
          DEBUG_TRACE("SSL_write() failed, error %d", err);
          return -1;
        }
      }
      else {
        err = 0;
      }
    }
    else
#endif
      if (fp != NULL) {
        n = (int)fwrite(buf, 1, (size_t)len, fp);
        if (ferror(fp)) {
          n = -1;
          err = ERRNO;
        }
        else {
          err = 0;
        }
      }
      else {
        n = (int)send(sock, buf, (len_t)len, MSG_NOSIGNAL);
        err = (n < 0) ? ERRNO : 0;
      }

      if (ctx->stop_flag) {
        return -1;
      }

      if ((n > 0) || (n == 0 && len == 0)) {
        /* some data has been read, or no data was requested */
        return n;
      }
      if (n == 0) {
        /* shutdown of the socket at client side */
        return -1;
      }
      if (n < 0) {
        /* socket error - check errno */
        DEBUG_TRACE("send() failed, error %d", err);

        /* TODO: error handling depending on the error code.
        * These codes are different between Windows and Linux.
        */
        return -1;
      }

      /* This code is not reached in the moment.
      * ==> Fix the TODOs above first. */

      if (timeout > 0) {
        clock_gettime(CLOCK_MONOTONIC, &now);
      }

  } while ((timeout <= 0) || (mg_difftimespec(&now, &start) <= timeout));

  (void)err; /* Avoid unused warning if NO_SSL is set and DEBUG_TRACE is not
             used */

  return -1;
}


static int64_t
push_all(struct mg_context *ctx,
  FILE *fp,
  SOCKET sock,
  SSL *ssl,
  const char *buf,
  int64_t len)
{
  double timeout = -1.0;
  int64_t n, nwritten = 0;

  if (ctx == NULL) {
    return -1;
  }

  if (ctx->config[REQUEST_TIMEOUT]) {
    timeout = atoi(ctx->config[REQUEST_TIMEOUT]) / 1000.0;
  }

  while (len > 0 && ctx->stop_flag == 0) {
    n = push(ctx, fp, sock, ssl, buf + nwritten, (int)len, timeout);
    if (n < 0) {
      if (nwritten == 0) {
        nwritten = n; /* Propagate the error */
      }
      break;
    }
    else if (n == 0) {
      break; /* No more data to write */
    }
    else {
      nwritten += n;
      len -= n;
    }
  }

  return nwritten;
}


/* Read from IO channel - opened file descriptor, socket, or SSL descriptor.
* Return negative value on error, or number of bytes read on success. */
static int
pull(FILE *fp, struct mg_connection *conn, char *buf, int len, double timeout)
{
  int nread, err;
  struct timespec start, now;

#ifdef _WIN32
  typedef int len_t;
#else
  typedef size_t len_t;
#endif

  if (timeout > 0) {
    memset(&start, 0, sizeof(start));
    memset(&now, 0, sizeof(now));
    clock_gettime(CLOCK_MONOTONIC, &start);
  }

  do {
    if (fp != NULL) {
      /* Use read() instead of fread(), because if we're reading from the
      * CGI pipe, fread() may block until IO buffer is filled up. We
      * cannot afford to block and must pass all read bytes immediately
      * to the client. */
      nread = (int)read(fileno(fp), buf, (size_t)len);
      err = (nread < 0) ? ERRNO : 0;

#ifndef NO_SSL
    }
    else if (conn->ssl != NULL) {
      nread = SSL_read(conn->ssl, buf, len);
      if (nread <= 0) {
        err = SSL_get_error(conn->ssl, nread);
        if ((err == 5 /* SSL_ERROR_SYSCALL */) && (nread == -1)) {
          err = ERRNO;
        }
        else {
          DEBUG_TRACE("SSL_read() failed, error %d", err);
          return -1;
        }
      }
      else {
        err = 0;
      }
#endif

    }
    else {
      nread = (int)recv(conn->client.sock, buf, (len_t)len, 0);
      err = (nread < 0) ? ERRNO : 0;
    }

    if (conn->ctx->stop_flag) {
      return -1;
    }

    if ((nread > 0) || (nread == 0 && len == 0)) {
      /* some data has been read, or no data was requested */
      return nread;
    }
    if (nread == 0) {
      /* shutdown of the socket at client side */
      return -1;
    }
    if (nread < 0) {
      /* socket error - check errno */
#ifdef _WIN32
      if (err == WSAEWOULDBLOCK) {
        /* standard case if called from close_socket_gracefully */
        return -1;
      }
      else if (err == WSAETIMEDOUT) {
        /* timeout is handled by the while loop  */
      }
      else {
        DEBUG_TRACE("recv() failed, error %d", err);
        return -1;
      }
#else
      /* TODO: POSIX returns either EAGAIN or EWOULDBLOCK in both cases,
      * if the timeout is reached and if the socket was set to non-
      * blocking in close_socket_gracefully, so we can not distinguish
      * here. We have to wait for the timeout in both cases for now.
      */
      if (err == EAGAIN || err == EWOULDBLOCK) {
        /* standard case if called from close_socket_gracefully
        * => should return -1 */
        /* or timeout occured
        * => the code must stay in the while loop */
      }
      else {
        DEBUG_TRACE("recv() failed, error %d", err);
        return -1;
      }
#endif
    }
    if (timeout > 0) {
      clock_gettime(CLOCK_MONOTONIC, &now);
    }
  } while ((timeout <= 0) || (mg_difftimespec(&now, &start) <= timeout));

  /* Timeout occured, but no data available. */
  return -1;
}


static int
pull_all(FILE *fp, struct mg_connection *conn, char *buf, int len)
{
  int n, nread = 0;
  double timeout = -1.0;

  if (conn->ctx->config[REQUEST_TIMEOUT]) {
    timeout = atoi(conn->ctx->config[REQUEST_TIMEOUT]) / 1000.0;
  }

  while (len > 0 && conn->ctx->stop_flag == 0) {
    n = pull(fp, conn, buf + nread, len, timeout);
    if (n < 0) {
      if (nread == 0) {
        nread = n; /* Propagate the error */
      }
      break;
    }
    else if (n == 0) {
      break; /* No more data to read */
    }
    else {
      conn->consumed_content += n;
      nread += n;
      len -= n;
    }
  }

  return nread;
}


static void
discard_unread_request_data(struct mg_connection *conn)
{
  char buf[MG_BUF_LEN];
  size_t to_read;
  int nread;

  if (conn == NULL) {
    return;
  }

  to_read = sizeof(buf);

  if (conn->is_chunked) {
    /* Chunked encoding: 1=chunk not read completely, 2=chunk read
    * completely */
    while (conn->is_chunked == 1) {
      nread = mg_read(conn, buf, to_read);
      if (nread <= 0) {
        break;
      }
    }

  }
  else {
    /* Not chunked: content length is known */
    while (conn->consumed_content < conn->content_len) {
      if (to_read
    >(size_t)(conn->content_len - conn->consumed_content)) {
        to_read = (size_t)(conn->content_len - conn->consumed_content);
      }

      nread = mg_read(conn, buf, to_read);
      if (nread <= 0) {
        break;
      }
    }
  }
}


static int
mg_read_inner(struct mg_connection *conn, void *buf, size_t len)
{
  int64_t n, buffered_len, nread;
  int64_t len64 =
    (int64_t)(len > INT_MAX ? INT_MAX : len); /* since the return value is
                                              * int, we may not read more
                                              * bytes */
  const char *body;

  if (conn == NULL) {
    return 0;
  }

  /* If Content-Length is not set for a PUT or POST request, read until
  * socket is closed */
  if (conn->consumed_content == 0 && conn->content_len == -1) {
    conn->content_len = INT64_MAX;
    conn->must_close = 1;
  }

  nread = 0;
  if (conn->consumed_content < conn->content_len) {
    /* Adjust number of bytes to read. */
    int64_t left_to_read = conn->content_len - conn->consumed_content;
    if (left_to_read < len64) {
      /* Do not read more than the total content length of the request.
      */
      len64 = left_to_read;
    }

    /* Return buffered data */
    buffered_len = (int64_t)(conn->data_len) - (int64_t)conn->request_len
      - conn->consumed_content;
    if (buffered_len > 0) {
      if (len64 < buffered_len) {
        buffered_len = len64;
      }
      body = conn->buf + conn->request_len + conn->consumed_content;
      memcpy(buf, body, (size_t)buffered_len);
      len64 -= buffered_len;
      conn->consumed_content += buffered_len;
      nread += buffered_len;
      buf = (char *)buf + buffered_len;
    }

    /* We have returned all buffered data. Read new data from the remote
    * socket.
    */
    if ((n = pull_all(NULL, conn, (char *)buf, (int)len64)) >= 0) {
      nread += n;
    }
    else {
      nread = (nread > 0 ? nread : n);
    }
  }
  return (int)nread;
}


static char
mg_getc(struct mg_connection *conn)
{
  char c;
  if (conn == NULL) {
    return 0;
  }
  conn->content_len++;
  if (mg_read_inner(conn, &c, 1) <= 0) {
    return (char)0;
  }
  return c;
}


int
mg_read(struct mg_connection *conn, void *buf, size_t len)
{
  if (len > INT_MAX) {
    len = INT_MAX;
  }

  if (conn == NULL) {
    return 0;
  }

  if (conn->is_chunked) {
    size_t all_read = 0;
    while (len > 0) {
      if (conn->chunk_remainder) {
        /* copy from the remainder of the last received chunk */
        long read_ret;
        size_t read_now =
          ((conn->chunk_remainder > len) ? (len)
            : (conn->chunk_remainder));

        conn->content_len += (int)read_now;
        read_ret =
          mg_read_inner(conn, (char *)buf + all_read, read_now);
        all_read += (size_t)read_ret;

        conn->chunk_remainder -= read_now;
        len -= read_now;

        if (conn->chunk_remainder == 0) {
          /* the rest of the data in the current chunk has been read
          */
          if ((mg_getc(conn) != '\r') || (mg_getc(conn) != '\n')) {
            /* Protocol violation */
            return -1;
          }
        }

      }
      else {
        /* fetch a new chunk */
        int i = 0;
        char lenbuf[64];
        char *end = 0;
        unsigned long chunkSize = 0;

        for (i = 0; i < ((int)sizeof(lenbuf) - 1); i++) {
          lenbuf[i] = mg_getc(conn);
          if (i > 0 && lenbuf[i] == '\r' && lenbuf[i - 1] != '\r') {
            continue;
          }
          if (i > 1 && lenbuf[i] == '\n' && lenbuf[i - 1] == '\r') {
            lenbuf[i + 1] = 0;
            chunkSize = strtoul(lenbuf, &end, 16);
            break;
          }
          if (!isalnum(lenbuf[i])) {
            /* illegal character for chunk length */
            return -1;
          }
        }
        if ((end == NULL) || (*end != '\r')) {
          /* chunksize not set correctly */
          return -1;
        }

        conn->chunk_remainder = chunkSize;
        if (chunkSize == 0) {
          /* regular end of content */
          conn->is_chunked = 2;
          break;
        }
      }
    }

    return (int)all_read;
  }
  return mg_read_inner(conn, buf, len);
}


int
mg_write(struct mg_connection *conn, const void *buf, size_t len)
{
  time_t now;
  int64_t n, total, allowed;

  if (conn == NULL) {
    return 0;
  }

  if (conn->throttle > 0) {
    if ((now = time(NULL)) != conn->last_throttle_time) {
      conn->last_throttle_time = now;
      conn->last_throttle_bytes = 0;
    }
    allowed = conn->throttle - conn->last_throttle_bytes;
    if (allowed > (int64_t)len) {
      allowed = (int64_t)len;
    }
    if ((total = push_all(conn->ctx,
      NULL,
      conn->client.sock,
      conn->ssl,
      (const char *)buf,
      (int64_t)allowed)) == allowed) {
      buf = (char *)buf + total;
      conn->last_throttle_bytes += total;
      while (total < (int64_t)len && conn->ctx->stop_flag == 0) {
        allowed = conn->throttle >(int64_t)len - total
          ? (int64_t)len - total
          : conn->throttle;
        if ((n = push_all(conn->ctx,
          NULL,
          conn->client.sock,
          conn->ssl,
          (const char *)buf,
          (int64_t)allowed)) != allowed) {
          break;
        }
        sleep(1);
        conn->last_throttle_bytes = allowed;
        conn->last_throttle_time = time(NULL);
        buf = (char *)buf + n;
        total += n;
      }
    }
  }
  else {
    total = push_all(conn->ctx,
      NULL,
      conn->client.sock,
      conn->ssl,
      (const char *)buf,
      (int64_t)len);
  }
  return (int)total;
}


/* Alternative alloc_vprintf() for non-compliant C runtimes */
static int
alloc_vprintf2(char **buf, const char *fmt, va_list ap)
{
  va_list ap_copy;
  size_t size = MG_BUF_LEN;
  int len = -1;

  *buf = NULL;
  while (len < 0) {
    if (*buf) {
      mg_free(*buf);
    }
    *buf = (char *)mg_malloc(size *= 4);
    if (!*buf) {
      break;
    }
    va_copy(ap_copy, ap);
    len = vsnprintf_impl(*buf, size - 1, fmt, ap_copy);
    va_end(ap_copy);
    *buf[size - 1] = 0;
  }

  return len;
}


/* Print message to buffer. If buffer is large enough to hold the message,
* return buffer. If buffer is to small, allocate large enough buffer on heap,
* and return allocated buffer. */
static int
alloc_vprintf(char **out_buf,
  char *prealloc_buf,
  size_t prealloc_size,
  const char *fmt,
  va_list ap)
{
  va_list ap_copy;
  int len;

  /* Windows is not standard-compliant, and vsnprintf() returns -1 if
  * buffer is too small. Also, older versions of msvcrt.dll do not have
  * _vscprintf().  However, if size is 0, vsnprintf() behaves correctly.
  * Therefore, we make two passes: on first pass, get required message
  * length.
  * On second pass, actually print the message. */
  va_copy(ap_copy, ap);
  len = vsnprintf_impl(NULL, 0, fmt, ap_copy);
  va_end(ap_copy);

  if (len < 0) {
    /* C runtime is not standard compliant, vsnprintf() returned -1.
    * Switch to alternative code path that uses incremental allocations.
    */
    va_copy(ap_copy, ap);
    len = alloc_vprintf2(out_buf, fmt, ap);
    va_end(ap_copy);

  }
  else if ((size_t)(len) >= prealloc_size) {
    /* The pre-allocated buffer not large enough. */
    /* Allocate a new buffer. */
    *out_buf = (char *)mg_malloc((size_t)(len)+1);
    if (!*out_buf) {
      /* Allocation failed. Return -1 as "out of memory" error. */
      return -1;
    }
    /* Buffer allocation successful. Store the string there. */
    va_copy(ap_copy, ap);
    IGNORE_UNUSED_RESULT(
      vsnprintf_impl(*out_buf, (size_t)(len)+1, fmt, ap_copy));
    va_end(ap_copy);

  }
  else {
    /* The pre-allocated buffer is large enough.
    * Use it to store the string and return the address. */
    va_copy(ap_copy, ap);
    IGNORE_UNUSED_RESULT(
      vsnprintf_impl(prealloc_buf, prealloc_size, fmt, ap_copy));
    va_end(ap_copy);
    *out_buf = prealloc_buf;
  }

  return len;
}


static int
mg_vprintf(struct mg_connection *conn, const char *fmt, va_list ap)
{
  char mem[MG_BUF_LEN];
  char *buf = NULL;
  int len;

  if ((len = alloc_vprintf(&buf, mem, sizeof(mem), fmt, ap)) > 0) {
    len = mg_write(conn, buf, (size_t)len);
  }
  if (buf != mem && buf != NULL) {
    mg_free(buf);
  }

  return len;
}


int
mg_printf(struct mg_connection *conn, const char *fmt, ...)
{
  va_list ap;
  int result;

  va_start(ap, fmt);
  result = mg_vprintf(conn, fmt, ap);
  va_end(ap);

  return result;
}


int
mg_url_decode(const char *src,
  int src_len,
  char *dst,
  int dst_len,
  int is_form_url_encoded)
{
  int i, j, a, b;
#define HEXTOI(x) (isdigit(x) ? x - '0' : x - 'W')

  for (i = j = 0; i < src_len && j < dst_len - 1; i++, j++) {
    if (i < src_len - 2 && src[i] == '%'
      && isxdigit(*(const unsigned char *)(src + i + 1))
      && isxdigit(*(const unsigned char *)(src + i + 2))) {
      a = tolower(*(const unsigned char *)(src + i + 1));
      b = tolower(*(const unsigned char *)(src + i + 2));
      dst[j] = (char)((HEXTOI(a) << 4) | HEXTOI(b));
      i += 2;
    }
    else if (is_form_url_encoded && src[i] == '+') {
      dst[j] = ' ';
    }
    else {
      dst[j] = src[i];
    }
  }

  dst[j] = '\0'; /* Null-terminate the destination */

  return i >= src_len ? j : -1;
}


int
mg_get_var(const char *data,
  size_t data_len,
  const char *name,
  char *dst,
  size_t dst_len)
{
  return mg_get_var2(data, data_len, name, dst, dst_len, 0);
}


int
mg_get_var2(const char *data,
  size_t data_len,
  const char *name,
  char *dst,
  size_t dst_len,
  size_t occurrence)
{
  const char *p, *e, *s;
  size_t name_len;
  int len;

  if (dst == NULL || dst_len == 0) {
    len = -2;
  }
  else if (data == NULL || name == NULL || data_len == 0) {
    len = -1;
    dst[0] = '\0';
  }
  else {
    name_len = strlen(name);
    e = data + data_len;
    len = -1;
    dst[0] = '\0';

    /* data is "var1=val1&var2=val2...". Find variable first */
    for (p = data; p + name_len < e; p++) {
      if ((p == data || p[-1] == '&') && p[name_len] == '='
        && !mg_strncasecmp(name, p, name_len) && 0 == occurrence--) {
        /* Point p to variable value */
        p += name_len + 1;

        /* Point s to the end of the value */
        s = (const char *)memchr(p, '&', (size_t)(e - p));
        if (s == NULL) {
          s = e;
        }
        /* assert(s >= p); */
        if (s < p) {
          return -3;
        }

        /* Decode variable into destination buffer */
        len = mg_url_decode(p, (int)(s - p), dst, (int)dst_len, 1);

        /* Redirect error code from -1 to -2 (destination buffer too
        * small). */
        if (len == -1) {
          len = -2;
        }
        break;
      }
    }
  }

  return len;
}


int
mg_get_cookie(const char *cookie_header,
  const char *var_name,
  char *dst,
  size_t dst_size)
{
  const char *s, *p, *end;
  int name_len, len = -1;

  if (dst == NULL || dst_size == 0) {
    len = -2;
  }
  else if (var_name == NULL || (s = cookie_header) == NULL) {
    len = -1;
    dst[0] = '\0';
  }
  else {
    name_len = (int)strlen(var_name);
    end = s + strlen(s);
    dst[0] = '\0';

    for (; (s = mg_strcasestr(s, var_name)) != NULL; s += name_len) {
      if (s[name_len] == '=') {
        s += name_len + 1;
        if ((p = strchr(s, ' ')) == NULL) {
          p = end;
        }
        if (p[-1] == ';') {
          p--;
        }
        if (*s == '"' && p[-1] == '"' && p > s + 1) {
          s++;
          p--;
        }
        if ((size_t)(p - s) < dst_size) {
          len = (int)(p - s);
          mg_strlcpy(dst, s, (size_t)len + 1);
        }
        else {
          len = -3;
        }
        break;
      }
    }
  }
  return len;
}


#if defined(USE_WEBSOCKET) || defined(USE_LUA)
static void
base64_encode(const unsigned char *src, int src_len, char *dst)
{
  static const char *b64 =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  int i, j, a, b, c;

  for (i = j = 0; i < src_len; i += 3) {
    a = src[i];
    b = i + 1 >= src_len ? 0 : src[i + 1];
    c = i + 2 >= src_len ? 0 : src[i + 2];

    dst[j++] = b64[a >> 2];
    dst[j++] = b64[((a & 3) << 4) | (b >> 4)];
    if (i + 1 < src_len) {
      dst[j++] = b64[(b & 15) << 2 | (c >> 6)];
    }
    if (i + 2 < src_len) {
      dst[j++] = b64[c & 63];
    }
  }
  while (j % 4 != 0) {
    dst[j++] = '=';
  }
  dst[j++] = '\0';
}
#endif


#if defined(USE_LUA)
static unsigned char
b64reverse(char letter)
{
  if (letter >= 'A' && letter <= 'Z') {
    return letter - 'A';
  }
  if (letter >= 'a' && letter <= 'z') {
    return letter - 'a' + 26;
  }
  if (letter >= '0' && letter <= '9') {
    return letter - '0' + 52;
  }
  if (letter == '+') {
    return 62;
  }
  if (letter == '/') {
    return 63;
  }
  if (letter == '=') {
    return 255; /* normal end */
  }
  return 254; /* error */
}


static int
base64_decode(const unsigned char *src, int src_len, char *dst, size_t *dst_len)
{
  int i;
  unsigned char a, b, c, d;

  *dst_len = 0;

  for (i = 0; i < src_len; i += 4) {
    a = b64reverse(src[i]);
    if (a >= 254) {
      return i;
    }

    b = b64reverse(i + 1 >= src_len ? 0 : src[i + 1]);
    if (b >= 254) {
      return i + 1;
    }

    c = b64reverse(i + 2 >= src_len ? 0 : src[i + 2]);
    if (c == 254) {
      return i + 2;
    }

    d = b64reverse(i + 3 >= src_len ? 0 : src[i + 3]);
    if (d == 254) {
      return i + 3;
    }

    dst[(*dst_len)++] = (a << 2) + (b >> 4);
    if (c != 255) {
      dst[(*dst_len)++] = (b << 4) + (c >> 2);
      if (d != 255) {
        dst[(*dst_len)++] = (c << 6) + d;
      }
    }
  }
  return -1;
}
#endif


static int
is_put_or_delete_method(const struct mg_connection *conn)
{
  if (conn) {
    const char *s = conn->request_info.request_method;
    return s != NULL && (!strcmp(s, "PUT") || !strcmp(s, "DELETE")
      || !strcmp(s, "MKCOL") || !strcmp(s, "PATCH"));
  }
  return 0;
}


static void
interpret_uri(struct mg_connection *conn,   /* in: request (must be valid) */
  char *filename,               /* out: filename */
  size_t filename_buf_len,      /* in: size of filename buffer */
struct file *filep,           /* out: file structure */
  int *is_found,                /* out: file is found (directly) */
  int *is_script_resource,      /* out: handled by a script? */
  int *is_websocket_request,    /* out: websocket connetion? */
  int *is_put_or_delete_request /* out: put/delete a file? */
  )
{
  /* TODO (high): Restructure this function */

#if !defined(NO_FILES)
  const char *uri = conn->request_info.local_uri;
  const char *root = conn->ctx->config[DOCUMENT_ROOT];
  const char *rewrite;
  struct vec a, b;
  int match_len;
  char gz_path[PATH_MAX];
  char const *accept_encoding;
  int truncated;
#if !defined(NO_CGI) || defined(USE_LUA)
  char *p;
#endif
#else
  (void)filename_buf_len; /* unused if NO_FILES is defined */
#endif

  memset(filep, 0, sizeof(*filep));
  *filename = 0;
  *is_found = 0;
  *is_script_resource = 0;
  *is_put_or_delete_request = is_put_or_delete_method(conn);

#if defined(USE_WEBSOCKET)
  *is_websocket_request = is_websocket_protocol(conn);
#if !defined(NO_FILES)
  if (*is_websocket_request && conn->ctx->config[WEBSOCKET_ROOT]) {
    root = conn->ctx->config[WEBSOCKET_ROOT];
  }
#endif /* !NO_FILES */
#else  /* USE_WEBSOCKET */
  *is_websocket_request = 0;
#endif /* USE_WEBSOCKET */

#if !defined(NO_FILES)
  /* Note that root == NULL is a regular use case here. This occurs,
  * if all requests are handled by callbacks, so the WEBSOCKET_ROOT
  * config is not required. */
  if (root == NULL) {
    /* all file related outputs have already been set to 0, just return
    */
    return;
  }

  /* Using buf_len - 1 because memmove() for PATH_INFO may shift part
  * of the path one byte on the right.
  * If document_root is NULL, leave the file empty. */
  mg_snprintf(
    conn, &truncated, filename, filename_buf_len - 1, "%s%s", root, uri);

  if (truncated) {
    goto interpret_cleanup;
  }

  rewrite = conn->ctx->config[REWRITE];
  while ((rewrite = next_option(rewrite, &a, &b)) != NULL) {
    if ((match_len = match_prefix(a.ptr, a.len, uri)) > 0) {
      mg_snprintf(conn,
        &truncated,
        filename,
        filename_buf_len - 1,
        "%.*s%s",
        (int)b.len,
        b.ptr,
        uri + match_len);
      break;
    }
  }

  if (truncated) {
    goto interpret_cleanup;
  }

  /* Local file path and name, corresponding to requested URI
  * is now stored in "filename" variable. */
  if (mg_stat(conn, filename, filep)) {
#if !defined(NO_CGI) || defined(USE_LUA) || defined(USE_DUKTAPE)
    /* File exists. Check if it is a script type. */
    if (0
#if !defined(NO_CGI)
      || match_prefix(conn->ctx->config[CGI_EXTENSIONS],
        strlen(conn->ctx->config[CGI_EXTENSIONS]),
        filename) > 0
#endif
#if defined(USE_LUA)
      || match_prefix(conn->ctx->config[LUA_SCRIPT_EXTENSIONS],
        strlen(conn->ctx->config[LUA_SCRIPT_EXTENSIONS]),
        filename) > 0
#endif
#if defined(USE_DUKTAPE)
      || match_prefix(conn->ctx->config[DUKTAPE_SCRIPT_EXTENSIONS],
        strlen(
          conn->ctx->config[DUKTAPE_SCRIPT_EXTENSIONS]),
        filename) > 0
#endif
      ) {
      /* The request addresses a CGI script or a Lua script. The URI
      * corresponds to the script itself (like /path/script.cgi),
      * and there is no additional resource path
      * (like /path/script.cgi/something).
      * Requests that modify (replace or delete) a resource, like
      * PUT and DELETE requests, should replace/delete the script
      * file.
      * Requests that read or write from/to a resource, like GET and
      * POST requests, should call the script and return the
      * generated response. */
      *is_script_resource = !*is_put_or_delete_request;
    }
#endif /* !defined(NO_CGI) || defined(USE_LUA) || defined(USE_DUKTAPE) */
    *is_found = 1;
    return;
  }

  /* If we can't find the actual file, look for the file
  * with the same name but a .gz extension. If we find it,
  * use that and set the gzipped flag in the file struct
  * to indicate that the response need to have the content-
  * encoding: gzip header.
  * We can only do this if the browser declares support. */
  if ((accept_encoding = mg_get_header(conn, "Accept-Encoding")) != NULL) {
    if (strstr(accept_encoding, "gzip") != NULL) {
      mg_snprintf(
        conn, &truncated, gz_path, sizeof(gz_path), "%s.gz", filename);

      if (truncated) {
        goto interpret_cleanup;
      }

      if (mg_stat(conn, gz_path, filep)) {
        if (filep) {
          filep->gzipped = 1;
          *is_found = 1;
        }
        /* Currently gz files can not be scripts. */
        return;
      }
    }
  }

#if !defined(NO_CGI) || defined(USE_LUA) || defined(USE_DUKTAPE)
  /* Support PATH_INFO for CGI scripts. */
  for (p = filename + strlen(filename); p > filename + 1; p--) {
    if (*p == '/') {
      *p = '\0';
      if ((0
#if !defined(NO_CGI)
        || match_prefix(conn->ctx->config[CGI_EXTENSIONS],
          strlen(conn->ctx->config[CGI_EXTENSIONS]),
          filename) > 0
#endif
#if defined(USE_LUA)
        || match_prefix(conn->ctx->config[LUA_SCRIPT_EXTENSIONS],
          strlen(
            conn->ctx->config[LUA_SCRIPT_EXTENSIONS]),
          filename) > 0
#endif
#if defined(USE_DUKTAPE)
        || match_prefix(
          conn->ctx->config[DUKTAPE_SCRIPT_EXTENSIONS],
          strlen(conn->ctx->config[DUKTAPE_SCRIPT_EXTENSIONS]),
          filename) > 0
#endif
        ) && mg_stat(conn, filename, filep)) {
        /* Shift PATH_INFO block one character right, e.g.
        * "/x.cgi/foo/bar\x00" => "/x.cgi\x00/foo/bar\x00"
        * conn->path_info is pointing to the local variable "path"
        * declared in handle_request(), so PATH_INFO is not valid
        * after handle_request returns. */
        conn->path_info = p + 1;
        memmove(p + 2, p + 1, strlen(p + 1) + 1); /* +1 is for
                                                  * trailing \0 */
        p[1] = '/';
        *is_script_resource = 1;
        break;
      }
      else {
        *p = '/';
      }
    }
  }
#endif /* !defined(NO_CGI) || defined(USE_LUA) || defined(USE_DUKTAPE) */
#endif /* !defined(NO_FILES) */
  return;

#if !defined(NO_FILES)
  /* Reset all outputs */
  interpret_cleanup:
                   memset(filep, 0, sizeof(*filep));
                   *filename = 0;
                   *is_found = 0;
                   *is_script_resource = 0;
                   *is_websocket_request = 0;
                   *is_put_or_delete_request = 0;
#endif /* !defined(NO_FILES) */
}


/* Check whether full request is buffered. Return:
* -1  if request is malformed
*  0  if request is not yet fully buffered
* >0  actual request length, including last \r\n\r\n */
static int
get_request_len(const char *buf, int buflen)
{
  const char *s, *e;
  int len = 0;

  for (s = buf, e = s + buflen - 1; len <= 0 && s < e; s++)
    /* Control characters are not allowed but >=128 is. */
    if (!isprint(*(const unsigned char *)s) && *s != '\r' && *s != '\n'
      && *(const unsigned char *)s < 128) {
      len = -1;
      break; /* [i_a] abort scan as soon as one malformed character is
             * found; */
             /* don't let subsequent \r\n\r\n win us over anyhow */
    }
    else if (s[0] == '\n' && s[1] == '\n') {
      len = (int)(s - buf) + 2;
    }
    else if (s[0] == '\n' && &s[1] < e && s[1] == '\r' && s[2] == '\n') {
      len = (int)(s - buf) + 3;
    }

    return len;
}


/* Convert month to the month number. Return -1 on error, or month number */
static int
get_month_index(const char *s)
{
  size_t i;

  for (i = 0; i < ARRAY_SIZE(month_names); i++) {
    if (!strcmp(s, month_names[i])) {
      return (int)i;
    }
  }

  return -1;
}


/* Parse UTC date-time string, and return the corresponding time_t value. */
static time_t
parse_date_string(const char *datetime)
{
#if 0
  char month_str[32] = { 0 };
  int second, minute, hour, day, month, year;
  time_t result = (time_t)0;
  struct tm tm;

  if ((sscanf(datetime,
    "%d/%3s/%d %d:%d:%d",
    &day,
    month_str,
    &year,
    &hour,
    &minute,
    &second) == 6) || (sscanf(datetime,
      "%d %3s %d %d:%d:%d",
      &day,
      month_str,
      &year,
      &hour,
      &minute,
      &second) == 6)
    || (sscanf(datetime,
      "%*3s, %d %3s %d %d:%d:%d",
      &day,
      month_str,
      &year,
      &hour,
      &minute,
      &second) == 6) || (sscanf(datetime,
        "%d-%3s-%d %d:%d:%d",
        &day,
        month_str,
        &year,
        &hour,
        &minute,
        &second) == 6)) {
    month = get_month_index(month_str);
    if ((month >= 0) && (year >= 1970)) {
      memset(&tm, 0, sizeof(tm));
      tm.tm_year = year - 1900;
      tm.tm_mon = month;
      tm.tm_mday = day;
      tm.tm_hour = hour;
      tm.tm_min = minute;
      tm.tm_sec = second;
      result = timegm(&tm);
    }
  }

  return result;
#else
  /* HACK Make Android shut-up >:-O */
  return 0;
#endif
}


/* Protect against directory disclosure attack by removing '..',
* excessive '/' and '\' characters */
static void
remove_double_dots_and_double_slashes(char *s)
{
  char *p = s;

  while (*s != '\0') {
    *p++ = *s++;
    if (s[-1] == '/' || s[-1] == '\\') {
      /* Skip all following slashes, backslashes and double-dots */
      while (s[0] != '\0') {
        if (s[0] == '/' || s[0] == '\\') {
          s++;
        }
        else if (s[0] == '.' && s[1] == '.') {
          s += 2;
        }
        else {
          break;
        }
      }
    }
  }
  *p = '\0';
}


static const struct {
  const char *extension;
  size_t ext_len;
  const char *mime_type;
} builtin_mime_types[] = {
  /* IANA registered MIME types (http://www.iana.org/assignments/media-types)
  * application types */
  { ".doc", 4, "application/msword" },
  { ".eps", 4, "application/postscript" },
  { ".exe", 4, "application/octet-stream" },
  { ".js", 3, "application/javascript" },
  { ".json", 5, "application/json" },
  { ".pdf", 4, "application/pdf" },
  { ".ps", 3, "application/postscript" },
  { ".rtf", 4, "application/rtf" },
  { ".xhtml", 6, "application/xhtml+xml" },
  { ".xsl", 4, "application/xml" },
  { ".xslt", 5, "application/xml" },

  /* fonts */
  { ".ttf", 4, "application/font-sfnt" },
  { ".cff", 4, "application/font-sfnt" },
  { ".otf", 4, "application/font-sfnt" },
  { ".aat", 4, "application/font-sfnt" },
  { ".sil", 4, "application/font-sfnt" },
  { ".pfr", 4, "application/font-tdpfr" },
  { ".woff", 5, "application/font-woff" },

  /* audio */
  { ".mp3", 4, "audio/mpeg" },
  { ".oga", 4, "audio/ogg" },
  { ".ogg", 4, "audio/ogg" },

  /* image */
  { ".gif", 4, "image/gif" },
  { ".ief", 4, "image/ief" },
  { ".jpeg", 5, "image/jpeg" },
  { ".jpg", 4, "image/jpeg" },
  { ".jpm", 4, "image/jpm" },
  { ".jpx", 4, "image/jpx" },
  { ".png", 4, "image/png" },
  { ".svg", 4, "image/svg+xml" },
  { ".tif", 4, "image/tiff" },
  { ".tiff", 5, "image/tiff" },

  /* model */
  { ".wrl", 4, "model/vrml" },

  /* text */
  { ".css", 4, "text/css" },
  { ".csv", 4, "text/csv" },
  { ".htm", 4, "text/html" },
  { ".html", 5, "text/html" },
  { ".sgm", 4, "text/sgml" },
  { ".shtm", 5, "text/html" },
  { ".shtml", 6, "text/html" },
  { ".txt", 4, "text/plain" },
  { ".xml", 4, "text/xml" },

  /* video */
  { ".mov", 4, "video/quicktime" },
  { ".mp4", 4, "video/mp4" },
  { ".mpeg", 5, "video/mpeg" },
  { ".mpg", 4, "video/mpeg" },
  { ".ogv", 4, "video/ogg" },
  { ".qt", 3, "video/quicktime" },

  /* not registered types
  * (http://reference.sitepoint.com/html/mime-types-full,
  * http://www.hansenb.pdx.edu/DMKB/dict/tutorials/mime_typ.php, ..) */
  { ".arj", 4, "application/x-arj-compressed" },
  { ".gz", 3, "application/x-gunzip" },
  { ".rar", 4, "application/x-arj-compressed" },
  { ".swf", 4, "application/x-shockwave-flash" },
  { ".tar", 4, "application/x-tar" },
  { ".tgz", 4, "application/x-tar-gz" },
  { ".torrent", 8, "application/x-bittorrent" },
  { ".ppt", 4, "application/x-mspowerpoint" },
  { ".xls", 4, "application/x-msexcel" },
  { ".zip", 4, "application/x-zip-compressed" },
  { ".aac",
  4,
  "audio/aac" }, /* http://en.wikipedia.org/wiki/Advanced_Audio_Coding */
  { ".aif", 4, "audio/x-aif" },
  { ".m3u", 4, "audio/x-mpegurl" },
  { ".mid", 4, "audio/x-midi" },
  { ".ra", 3, "audio/x-pn-realaudio" },
  { ".ram", 4, "audio/x-pn-realaudio" },
  { ".wav", 4, "audio/x-wav" },
  { ".bmp", 4, "image/bmp" },
  { ".ico", 4, "image/x-icon" },
  { ".pct", 4, "image/x-pct" },
  { ".pict", 5, "image/pict" },
  { ".rgb", 4, "image/x-rgb" },
  { ".webm", 5, "video/webm" }, /* http://en.wikipedia.org/wiki/WebM */
  { ".asf", 4, "video/x-ms-asf" },
  { ".avi", 4, "video/x-msvideo" },
  { ".m4v", 4, "video/x-m4v" },
  { NULL, 0, NULL } };


const char *
mg_get_builtin_mime_type(const char *path)
{
  const char *ext;
  size_t i, path_len;

  path_len = strlen(path);

  for (i = 0; builtin_mime_types[i].extension != NULL; i++) {
    ext = path + (path_len - builtin_mime_types[i].ext_len);
    if (path_len > builtin_mime_types[i].ext_len
      && mg_strcasecmp(ext, builtin_mime_types[i].extension) == 0) {
      return builtin_mime_types[i].mime_type;
    }
  }

  return "text/plain";
}


/* Look at the "path" extension and figure what mime type it has.
* Store mime type in the vector. */
static void
get_mime_type(struct mg_context *ctx, const char *path, struct vec *vec)
{
  struct vec ext_vec, mime_vec;
  const char *list, *ext;
  size_t path_len;

  path_len = strlen(path);

  if (ctx == NULL || vec == NULL) {
    return;
  }

  /* Scan user-defined mime types first, in case user wants to
  * override default mime types. */
  list = ctx->config[EXTRA_MIME_TYPES];
  while ((list = next_option(list, &ext_vec, &mime_vec)) != NULL) {
    /* ext now points to the path suffix */
    ext = path + path_len - ext_vec.len;
    if (mg_strncasecmp(ext, ext_vec.ptr, ext_vec.len) == 0) {
      *vec = mime_vec;
      return;
    }
  }

  vec->ptr = mg_get_builtin_mime_type(path);
  vec->len = strlen(vec->ptr);
}


/* Stringify binary data. Output buffer must be twice as big as input,
* because each byte takes 2 bytes in string representation */
static void
bin2str(char *to, const unsigned char *p, size_t len)
{
  static const char *hex = "0123456789abcdef";

  for (; len--; p++) {
    *to++ = hex[p[0] >> 4];
    *to++ = hex[p[0] & 0x0f];
  }
  *to = '\0';
}


/* Return stringified MD5 hash for list of strings. Buffer must be 33 bytes. */
char *
mg_md5(char buf[33], ...)
{
  unsigned char hash[16];
  const char *p;
  va_list ap;
  MD5_CTX ctx;

  MD5_Init(&ctx);

  va_start(ap, buf);
  while ((p = va_arg(ap, const char *)) != NULL) {
    MD5_Update(&ctx, (const void *)p, strlen(p));
  }
  va_end(ap);

  MD5_Final(hash, &ctx);
  bin2str(buf, hash, sizeof(hash));
  return buf;
}


/* Check the user's password, return 1 if OK */
static int
check_password(const char *method,
  const char *ha1,
  const char *uri,
  const char *nonce,
  const char *nc,
  const char *cnonce,
  const char *qop,
  const char *response)
{
  char ha2[32 + 1], expected_response[32 + 1];

  /* Some of the parameters may be NULL */
  if (method == NULL || nonce == NULL || nc == NULL || cnonce == NULL
    || qop == NULL
    || response == NULL) {
    return 0;
  }

  /* NOTE(lsm): due to a bug in MSIE, we do not compare the URI */
  if (strlen(response) != 32) {
    return 0;
  }

  mg_md5(ha2, method, ":", uri, NULL);
  mg_md5(expected_response,
    ha1,
    ":",
    nonce,
    ":",
    nc,
    ":",
    cnonce,
    ":",
    qop,
    ":",
    ha2,
    NULL);

  return mg_strcasecmp(response, expected_response) == 0;
}


/* Use the global passwords file, if specified by auth_gpass option,
* or search for .htpasswd in the requested directory. */
static void
open_auth_file(struct mg_connection *conn, const char *path, struct file *filep)
{
  if (conn != NULL && conn->ctx != NULL) {
    char name[PATH_MAX];
    const char *p, *e, *gpass = conn->ctx->config[GLOBAL_PASSWORDS_FILE];
    struct file file = STRUCT_FILE_INITIALIZER;
    int truncated;

    if (gpass != NULL) {
      /* Use global passwords file */
      if (!mg_fopen(conn, gpass, "r", filep)) {
#ifdef DEBUG
        mg_cry(conn, "fopen(%s): %s", gpass, strerror(ERRNO));
#endif
      }
      /* Important: using local struct file to test path for is_directory
      * flag. If filep is used, mg_stat() makes it appear as if auth file
      * was opened. */
    }
    else if (mg_stat(conn, path, &file) && file.is_directory) {
      mg_snprintf(conn,
        &truncated,
        name,
        sizeof(name),
        "%s/%s",
        path,
        PASSWORDS_FILE_NAME);

      if (truncated || !mg_fopen(conn, name, "r", filep)) {
#ifdef DEBUG
        mg_cry(conn, "fopen(%s): %s", name, strerror(ERRNO));
#endif
      }
    }
    else {
      /* Try to find .htpasswd in requested directory. */
      for (p = path, e = p + strlen(p) - 1; e > p; e--) {
        if (e[0] == '/') {
          break;
        }
      }
      mg_snprintf(conn,
        &truncated,
        name,
        sizeof(name),
        "%.*s%s",
        (int)(e - p),
        p,
        PASSWORDS_FILE_NAME);

      if (truncated || !mg_fopen(conn, name, "r", filep)) {
#ifdef DEBUG
        mg_cry(conn, "fopen(%s): %s", name, strerror(ERRNO));
#endif
      }
    }
  }
}


/* Parsed Authorization header */
struct ah {
  char *user, *uri, *cnonce, *response, *qop, *nc, *nonce;
};


/* Return 1 on success. Always initializes the ah structure. */
static int
parse_auth_header(struct mg_connection *conn,
  char *buf,
  size_t buf_size,
struct ah *ah)
{
  char *name, *value, *s;
  const char *auth_header;
  uint64_t nonce;

  if (!ah || !conn) {
    return 0;
  }

  (void)memset(ah, 0, sizeof(*ah));
  if ((auth_header = mg_get_header(conn, "Authorization")) == NULL
    || mg_strncasecmp(auth_header, "Digest ", 7) != 0) {
    return 0;
  }

  /* Make modifiable copy of the auth header */
  (void)mg_strlcpy(buf, auth_header + 7, buf_size);
  s = buf;

  /* Parse authorization header */
  for (;;) {
    /* Gobble initial spaces */
    while (isspace(*(unsigned char *)s)) {
      s++;
    }
    name = skip_quoted(&s, "=", " ", 0);
    /* Value is either quote-delimited, or ends at first comma or space. */
    if (s[0] == '\"') {
      s++;
      value = skip_quoted(&s, "\"", " ", '\\');
      if (s[0] == ',') {
        s++;
      }
    }
    else {
      value = skip_quoted(&s, ", ", " ", 0); /* IE uses commas, FF uses
                                             * spaces */
    }
    if (*name == '\0') {
      break;
    }

    if (!strcmp(name, "username")) {
      ah->user = value;
    }
    else if (!strcmp(name, "cnonce")) {
      ah->cnonce = value;
    }
    else if (!strcmp(name, "response")) {
      ah->response = value;
    }
    else if (!strcmp(name, "uri")) {
      ah->uri = value;
    }
    else if (!strcmp(name, "qop")) {
      ah->qop = value;
    }
    else if (!strcmp(name, "nc")) {
      ah->nc = value;
    }
    else if (!strcmp(name, "nonce")) {
      ah->nonce = value;
    }
  }

#ifndef NO_NONCE_CHECK
  /* Read the nonce from the response. */
  if (ah->nonce == NULL) {
    return 0;
  }
  s = NULL;
  nonce = strtoull(ah->nonce, &s, 10);
  if ((s == NULL) || (*s != 0)) {
    return 0;
  }

  /* Convert the nonce from the client to a number. */
  nonce ^= conn->ctx->auth_nonce_mask;

  /* The converted number corresponds to the time the nounce has been
  * created. This should not be earlier than the server start. */
  /* Server side nonce check is valuable in all situations but one:
  * if the server restarts frequently, but the client should not see
  * that, so the server should accept nonces from previous starts. */
  /* However, the reasonable default is to not accept a nonce from a
  * previous start, so if anyone changed the access rights between
  * two restarts, a new login is required. */
  if (nonce < (uint64_t)conn->ctx->start_time) {
    /* nonce is from a previous start of the server and no longer valid
    * (replay attack?) */
    return 0;
  }
  /* Check if the nonce is too high, so it has not (yet) been used by the
  * server. */
  if (nonce >= ((uint64_t)conn->ctx->start_time + conn->ctx->nonce_count)) {
    return 0;
  }
#endif

  /* CGI needs it as REMOTE_USER */
  if (ah->user != NULL) {
    conn->request_info.remote_user = mg_strdup(ah->user);
  }
  else {
    return 0;
  }

  return 1;
}


static char *
mg_fgets(char *buf, size_t size, struct file *filep, char **p)
{
  char *eof;
  size_t len;
  char *memend;

  if (!filep) {
    return NULL;
  }

  if (filep->membuf != NULL && *p != NULL) {
    memend = (char *)&filep->membuf[filep->size];
    /* Search for \n from p till the end of stream */
    eof = (char *)memchr(*p, '\n', (size_t)(memend - *p));
    if (eof != NULL) {
      eof += 1; /* Include \n */
    }
    else {
      eof = memend; /* Copy remaining data */
    }
    len = (size_t)(eof - *p) > size - 1 ? size - 1 : (size_t)(eof - *p);
    memcpy(buf, *p, len);
    buf[len] = '\0';
    *p += len;
    return len ? eof : NULL;
  }
  else if (filep->fp != NULL) {
    return fgets(buf, (int)size, filep->fp);
  }
  else {
    return NULL;
  }
}

struct read_auth_file_struct {
  struct mg_connection *conn;
  struct ah ah;
  char *domain;
  char buf[256 + 256 + 40];
  char *f_user;
  char *f_domain;
  char *f_ha1;
};


static int
read_auth_file(struct file *filep, struct read_auth_file_struct *workdata)
{
  char *p;
  int is_authorized = 0;
  struct file fp;
  size_t l;

  if (!filep || !workdata) {
    return 0;
  }

  /* Loop over passwords file */
  p = (char *)filep->membuf;
  while (mg_fgets(workdata->buf, sizeof(workdata->buf), filep, &p) != NULL) {
    l = strlen(workdata->buf);
    while (l > 0) {
      if (isspace(workdata->buf[l - 1])
        || iscntrl(workdata->buf[l - 1])) {
        l--;
        workdata->buf[l] = 0;
      }
      else
        break;
    }
    if (l < 1) {
      continue;
    }

    workdata->f_user = workdata->buf;

    if (workdata->f_user[0] == ':') {
      /* user names may not contain a ':' and may not be empty,
      * so lines starting with ':' may be used for a special purpose */
      if (workdata->f_user[1] == '#') {
        /* :# is a comment */
        continue;
      }
      else if (!strncmp(workdata->f_user + 1, "include=", 8)) {
        if (mg_fopen(workdata->conn, workdata->f_user + 9, "r", &fp)) {
          is_authorized = read_auth_file(&fp, workdata);
          mg_fclose(&fp);
        }
        else {
          mg_cry(workdata->conn,
            "%s: cannot open authorization file: %s",
            __func__,
            workdata->buf);
        }
        continue;
      }
      /* everything is invalid for the moment (might change in the
      * future) */
      mg_cry(workdata->conn,
        "%s: syntax error in authorization file: %s",
        __func__,
        workdata->buf);
      continue;
    }

    workdata->f_domain = strchr(workdata->f_user, ':');
    if (workdata->f_domain == NULL) {
      mg_cry(workdata->conn,
        "%s: syntax error in authorization file: %s",
        __func__,
        workdata->buf);
      continue;
    }
    *(workdata->f_domain) = 0;
    (workdata->f_domain)++;

    workdata->f_ha1 = strchr(workdata->f_domain, ':');
    if (workdata->f_ha1 == NULL) {
      mg_cry(workdata->conn,
        "%s: syntax error in authorization file: %s",
        __func__,
        workdata->buf);
      continue;
    }
    *(workdata->f_ha1) = 0;
    (workdata->f_ha1)++;

    if (!strcmp(workdata->ah.user, workdata->f_user)
      && !strcmp(workdata->domain, workdata->f_domain)) {
      return check_password(workdata->conn->request_info.request_method,
        workdata->f_ha1,
        workdata->ah.uri,
        workdata->ah.nonce,
        workdata->ah.nc,
        workdata->ah.cnonce,
        workdata->ah.qop,
        workdata->ah.response);
    }
  }

  return is_authorized;
}


/* Authorize against the opened passwords file. Return 1 if authorized. */
static int
authorize(struct mg_connection *conn, struct file *filep)
{
  struct read_auth_file_struct workdata;
  char buf[MG_BUF_LEN];

  if (!conn || !conn->ctx) {
    return 0;
  }

  memset(&workdata, 0, sizeof(workdata));
  workdata.conn = conn;

  if (!parse_auth_header(conn, buf, sizeof(buf), &workdata.ah)) {
    return 0;
  }
  workdata.domain = conn->ctx->config[AUTHENTICATION_DOMAIN];

  return read_auth_file(filep, &workdata);
}


/* Return 1 if request is authorised, 0 otherwise. */
static int
check_authorization(struct mg_connection *conn, const char *path)
{
  char fname[PATH_MAX];
  struct vec uri_vec, filename_vec;
  const char *list;
  struct file file = STRUCT_FILE_INITIALIZER;
  int authorized = 1, truncated;

  if (!conn || !conn->ctx) {
    return 0;
  }

  list = conn->ctx->config[PROTECT_URI];
  while ((list = next_option(list, &uri_vec, &filename_vec)) != NULL) {
    if (!memcmp(conn->request_info.local_uri, uri_vec.ptr, uri_vec.len)) {
      mg_snprintf(conn,
        &truncated,
        fname,
        sizeof(fname),
        "%.*s",
        (int)filename_vec.len,
        filename_vec.ptr);

      if (truncated || !mg_fopen(conn, fname, "r", &file)) {
        mg_cry(conn,
          "%s: cannot open %s: %s",
          __func__,
          fname,
          strerror(errno));
      }
      break;
    }
  }

  if (!is_file_opened(&file)) {
    open_auth_file(conn, path, &file);
  }

  if (is_file_opened(&file)) {
    authorized = authorize(conn, &file);
    mg_fclose(&file);
  }

  return authorized;
}


static void
send_authorization_request(struct mg_connection *conn)
{
  char date[64];
  time_t curtime = time(NULL);

  if (conn && conn->ctx) {
    uint64_t nonce = (uint64_t)(conn->ctx->start_time);

    (void)pthread_mutex_lock(&conn->ctx->nonce_mutex);
    nonce += conn->ctx->nonce_count;
    ++conn->ctx->nonce_count;
    (void)pthread_mutex_unlock(&conn->ctx->nonce_mutex);

    nonce ^= conn->ctx->auth_nonce_mask;
    conn->status_code = 401;
    conn->must_close = 1;

    gmt_time_string(date, sizeof(date), &curtime);

    mg_printf(conn, "HTTP/1.1 401 Unauthorized\r\n");
    send_no_cache_header(conn);
    mg_printf(conn,
      "Date: %s\r\n"
      "Connection: %s\r\n"
      "Content-Length: 0\r\n"
      "WWW-Authenticate: Digest qop=\"auth\", realm=\"%s\", "
      "nonce=\"%" UINT64_FMT "\"\r\n\r\n",
      date,
      suggest_connection_header(conn),
      conn->ctx->config[AUTHENTICATION_DOMAIN],
      nonce);
  }
}


#if !defined(NO_FILES)
static int
is_authorized_for_put(struct mg_connection *conn)
{
  if (conn) {
    struct file file = STRUCT_FILE_INITIALIZER;
    const char *passfile = conn->ctx->config[PUT_DELETE_PASSWORDS_FILE];
    int ret = 0;

    if (passfile != NULL && mg_fopen(conn, passfile, "r", &file)) {
      ret = authorize(conn, &file);
      mg_fclose(&file);
    }

    return ret;
  }
  return 0;
}
#endif


int
mg_modify_passwords_file(const char *fname,
  const char *domain,
  const char *user,
  const char *pass)
{
  int found, i;
  char line[512], u[512] = "", d[512] = "", ha1[33], tmp[PATH_MAX + 8];
  FILE *fp, *fp2;

  found = 0;
  fp = fp2 = NULL;

  /* Regard empty password as no password - remove user record. */
  if (pass != NULL && pass[0] == '\0') {
    pass = NULL;
  }

  /* Other arguments must not be empty */
  if (fname == NULL || domain == NULL || user == NULL) {
    return 0;
  }

  /* Using the given file format, user name and domain must not contain ':'
  */
  if (strchr(user, ':') != NULL) {
    return 0;
  }
  if (strchr(domain, ':') != NULL) {
    return 0;
  }

  /* Do not allow control characters like newline in user name and domain.
  * Do not allow excessively long names either. */
  for (i = 0; i < 255 && user[i] != 0; i++) {
    if (iscntrl(user[i])) {
      return 0;
    }
  }
  if (user[i]) {
    return 0;
  }
  for (i = 0; i < 255 && domain[i] != 0; i++) {
    if (iscntrl(domain[i])) {
      return 0;
    }
  }
  if (domain[i]) {
    return 0;
  }

  /* The maximum length of the path to the password file is limited */
  if ((strlen(fname) + 4) >= PATH_MAX) {
    return 0;
  }

  /* Create a temporary file name. Length has been checked before. */
  strcpy(tmp, fname);
  strcat(tmp, ".tmp");

  /* Create the file if does not exist */
  /* Use of fopen here is OK, since fname is only ASCII */
  if ((fp = fopen(fname, "a+")) != NULL) {
    (void)fclose(fp);
  }

  /* Open the given file and temporary file */
  if ((fp = fopen(fname, "r")) == NULL) {
    return 0;
  }
  else if ((fp2 = fopen(tmp, "w+")) == NULL) {
    fclose(fp);
    return 0;
  }

  /* Copy the stuff to temporary file */
  while (fgets(line, sizeof(line), fp) != NULL) {
    if (sscanf(line, "%255[^:]:%255[^:]:%*s", u, d) != 2) {
      continue;
    }
    u[255] = 0;
    d[255] = 0;

    if (!strcmp(u, user) && !strcmp(d, domain)) {
      found++;
      if (pass != NULL) {
        mg_md5(ha1, user, ":", domain, ":", pass, NULL);
        fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
      }
    }
    else {
      fprintf(fp2, "%s", line);
    }
  }

  /* If new user, just add it */
  if (!found && pass != NULL) {
    mg_md5(ha1, user, ":", domain, ":", pass, NULL);
    fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
  }

  /* Close files */
  fclose(fp);
  fclose(fp2);

  /* Put the temp file in place of real file */
  IGNORE_UNUSED_RESULT(remove(fname));
  IGNORE_UNUSED_RESULT(rename(tmp, fname));

  return 1;
}


static int
is_valid_port(unsigned long port)
{
  return port < 0xffff;
}


static int
mg_inet_pton(int af, const char *src, void *dst, size_t dstlen)
{
  struct addrinfo hints, *res, *ressave;
  int ret = 0;

  memset(&hints, 0, sizeof(struct addrinfo));
  hints.ai_family = af;

  if (getaddrinfo(src, NULL, &hints, &res) != 0) {
    /* bad src string or bad address family */
    return 0;
  }

  ressave = res;

  while (res) {
    if (dstlen >= res->ai_addrlen) {
      memcpy(dst, res->ai_addr, res->ai_addrlen);
      ret = 1;
    }
    res = res->ai_next;
  }

  freeaddrinfo(ressave);
  return ret;
}


static int
connect_socket(struct mg_context *ctx /* may be NULL */,
  const char *host,
  int port,
  int use_ssl,
  char *ebuf,
  size_t ebuf_len,
  SOCKET *sock /* output: socket, must not be NULL */,
union usa *sa /* output: socket address, must not be NULL  */
  )
{
  int ip_ver = 0;
  *sock = INVALID_SOCKET;
  memset(sa, 0, sizeof(*sa));

  if (ebuf_len > 0) {
    *ebuf = 0;
  }

  if (host == NULL) {
    mg_snprintf(NULL,
      NULL, /* No truncation check for ebuf */
      ebuf,
      ebuf_len,
      "%s",
      "NULL host");
    return 0;
  }

  if (port < 0 || !is_valid_port((unsigned)port)) {
    mg_snprintf(NULL,
      NULL, /* No truncation check for ebuf */
      ebuf,
      ebuf_len,
      "%s",
      "invalid port");
    return 0;
  }

  if (use_ssl && (SSLv23_client_method == NULL)) {
    mg_snprintf(NULL,
      NULL, /* No truncation check for ebuf */
      ebuf,
      ebuf_len,
      "%s",
      "SSL is not initialized");
    return 0;
  }

  if (mg_inet_pton(AF_INET, host, &sa->sin, sizeof(sa->sin))) {
    sa->sin.sin_port = htons((uint16_t)port);
    ip_ver = 4;
#ifdef USE_IPV6
  }
  else if (mg_inet_pton(AF_INET6, host, &sa->sin6, sizeof(sa->sin6))) {
    sa->sin6.sin6_port = htons((uint16_t)port);
    ip_ver = 6;
  }
  else if (host[0] == '[') {
    /* While getaddrinfo on Windows will work with [::1],
    * getaddrinfo on Linux only works with ::1 (without []). */
    size_t l = strlen(host + 1);
    char *h = l > 1 ? mg_strdup(host + 1) : NULL;
    if (h) {
      h[l - 1] = 0;
      if (mg_inet_pton(AF_INET6, h, &sa->sin6, sizeof(sa->sin6))) {
        sa->sin6.sin6_port = htons((uint16_t)port);
        ip_ver = 6;
      }
      mg_free(h);
    }
#endif
  }

  if (ip_ver == 0) {
    mg_snprintf(NULL,
      NULL, /* No truncation check for ebuf */
      ebuf,
      ebuf_len,
      "%s",
      "host not found");
    return 0;
  }

  if (ip_ver == 4) {
    *sock = socket(PF_INET, SOCK_STREAM, 0);
  }
#ifdef USE_IPV6
  else if (ip_ver == 6) {
    *sock = socket(PF_INET6, SOCK_STREAM, 0);
  }
#endif

  if (*sock == INVALID_SOCKET) {
    mg_snprintf(NULL,
      NULL, /* No truncation check for ebuf */
      ebuf,
      ebuf_len,
      "socket(): %s",
      strerror(ERRNO));
    return 0;
  }

  set_close_on_exec(*sock, fc(ctx));

  if ((ip_ver == 4)
    && (connect(*sock, (struct sockaddr *)&sa->sin, sizeof(sa->sin))
      == 0)) {
    /* connected with IPv4 */
    return 1;
  }

#ifdef USE_IPV6
  if ((ip_ver == 6)
    && (connect(*sock, (struct sockaddr *)&sa->sin6, sizeof(sa->sin6))
      == 0)) {
    /* connected with IPv6 */
    return 1;
  }
#endif

  /* Not connected */
  mg_snprintf(NULL,
    NULL, /* No truncation check for ebuf */
    ebuf,
    ebuf_len,
    "connect(%s:%d): %s",
    host,
    port,
    strerror(ERRNO));
  closesocket(*sock);
  *sock = INVALID_SOCKET;
  return 0;
}


int
mg_url_encode(const char *src, char *dst, size_t dst_len)
{
  static const char *dont_escape = "._-$,;~()";
  static const char *hex = "0123456789abcdef";
  char *pos = dst;
  const char *end = dst + dst_len - 1;

  for (; *src != '\0' && pos < end; src++, pos++) {
    if (isalnum(*(const unsigned char *)src)
      || strchr(dont_escape, *(const unsigned char *)src) != NULL) {
      *pos = *src;
    }
    else if (pos + 2 < end) {
      pos[0] = '%';
      pos[1] = hex[(*(const unsigned char *)src) >> 4];
      pos[2] = hex[(*(const unsigned char *)src) & 0xf];
      pos += 2;
    }
    else {
      break;
    }
  }

  *pos = '\0';
  return (*src == '\0') ? (int)(pos - dst) : -1;
}


static void
print_dir_entry(struct de *de)
{
  char size[64], mod[64], href[PATH_MAX];
  struct tm *tm;

  if (de->file.is_directory) {
    mg_snprintf(de->conn,
      NULL, /* Buffer is big enough */
      size,
      sizeof(size),
      "%s",
      "[DIRECTORY]");
  }
  else {
    /* We use (signed) cast below because MSVC 6 compiler cannot
    * convert unsigned __int64 to double. Sigh. */
    if (de->file.size < 1024) {
      mg_snprintf(de->conn,
        NULL, /* Buffer is big enough */
        size,
        sizeof(size),
        "%d",
        (int)de->file.size);
    }
    else if (de->file.size < 0x100000) {
      mg_snprintf(de->conn,
        NULL, /* Buffer is big enough */
        size,
        sizeof(size),
        "%.1fk",
        (double)de->file.size / 1024.0);
    }
    else if (de->file.size < 0x40000000) {
      mg_snprintf(de->conn,
        NULL, /* Buffer is big enough */
        size,
        sizeof(size),
        "%.1fM",
        (double)de->file.size / 1048576);
    }
    else {
      mg_snprintf(de->conn,
        NULL, /* Buffer is big enough */
        size,
        sizeof(size),
        "%.1fG",
        (double)de->file.size / 1073741824);
    }
  }

  /* Note: mg_snprintf will not cause a buffer overflow above.
  * So, string truncation checks are not required here. */

  tm = localtime(&de->file.last_modified);
  if (tm != NULL) {
    strftime(mod, sizeof(mod), "%d-%b-%Y %H:%M", tm);
  }
  else {
    mg_strlcpy(mod, "01-Jan-1970 00:00", sizeof(mod));
    mod[sizeof(mod) - 1] = '\0';
  }
  mg_url_encode(de->file_name, href, sizeof(href));
  de->conn->num_bytes_sent +=
    mg_printf(de->conn,
      "<tr><td><a href=\"%s%s%s\">%s%s</a></td>"
      "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
      de->conn->request_info.local_uri,
      href,
      de->file.is_directory ? "/" : "",
      de->file_name,
      de->file.is_directory ? "/" : "",
      mod,
      size);
}


/* This function is called from send_directory() and used for
* sorting directory entries by size, or name, or modification time.
* On windows, __cdecl specification is needed in case if project is built
* with __stdcall convention. qsort always requires __cdels callback. */
static int WINCDECL
compare_dir_entries(const void *p1, const void *p2)
{
  if (p1 && p2) {
    const struct de *a = (const struct de *)p1, *b = (const struct de *)p2;
    const char *query_string = a->conn->request_info.query_string;
    int cmp_result = 0;

    if (query_string == NULL) {
      query_string = "na";
    }

    if (a->file.is_directory && !b->file.is_directory) {
      return -1; /* Always put directories on top */
    }
    else if (!a->file.is_directory && b->file.is_directory) {
      return 1; /* Always put directories on top */
    }
    else if (*query_string == 'n') {
      cmp_result = strcmp(a->file_name, b->file_name);
    }
    else if (*query_string == 's') {
      cmp_result = a->file.size == b->file.size
        ? 0
        : a->file.size > b->file.size ? 1 : -1;
    }
    else if (*query_string == 'd') {
      cmp_result =
        (a->file.last_modified == b->file.last_modified)
        ? 0
        : ((a->file.last_modified > b->file.last_modified) ? 1
          : -1);
    }

    return query_string[1] == 'd' ? -cmp_result : cmp_result;
  }
  return 0;
}


static int
must_hide_file(struct mg_connection *conn, const char *path)
{
  if (conn && conn->ctx) {
    const char *pw_pattern = "**" PASSWORDS_FILE_NAME "$";
    const char *pattern = conn->ctx->config[HIDE_FILES];
    return match_prefix(pw_pattern, strlen(pw_pattern), path) > 0
      || (pattern != NULL
        && match_prefix(pattern, strlen(pattern), path) > 0);
  }
  return 0;
}


static int
scan_directory(struct mg_connection *conn,
  const char *dir,
  void *data,
  void(*cb)(struct de *, void *))
{
  char path[PATH_MAX];
  struct dirent *dp;
  DIR *dirp;
  struct de de;
  int truncated;

  if ((dirp = opendir(dir)) == NULL) {
    return 0;
  }
  else {
    de.conn = conn;

    while ((dp = readdir(dirp)) != NULL) {
      /* Do not show current dir and hidden files */
      if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, "..")
        || must_hide_file(conn, dp->d_name)) {
        continue;
      }

      mg_snprintf(
        conn, &truncated, path, sizeof(path), "%s/%s", dir, dp->d_name);

      /* If we don't memset stat structure to zero, mtime will have
      * garbage and strftime() will segfault later on in
      * print_dir_entry(). memset is required only if mg_stat()
      * fails. For more details, see
      * http://code.google.com/p/mongoose/issues/detail?id=79 */
      memset(&de.file, 0, sizeof(de.file));

      if (truncated) {
        /* If the path is not complete, skip processing. */
        continue;
      }

      if (!mg_stat(conn, path, &de.file)) {
        mg_cry(conn,
          "%s: mg_stat(%s) failed: %s",
          __func__,
          path,
          strerror(ERRNO));
      }
      de.file_name = dp->d_name;
      cb(&de, data);
    }
    (void)closedir(dirp);
  }
  return 1;
}


#if !defined(NO_FILES)
static int
remove_directory(struct mg_connection *conn, const char *dir)
{
  char path[PATH_MAX];
  struct dirent *dp;
  DIR *dirp;
  struct de de;
  int truncated;
  int ok = 1;

  if ((dirp = opendir(dir)) == NULL) {
    return 0;
  }
  else {
    de.conn = conn;

    while ((dp = readdir(dirp)) != NULL) {
      /* Do not show current dir (but show hidden files as they will
      * also be removed) */
      if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, "..")) {
        continue;
      }

      mg_snprintf(
        conn, &truncated, path, sizeof(path), "%s/%s", dir, dp->d_name);

      /* If we don't memset stat structure to zero, mtime will have
      * garbage and strftime() will segfault later on in
      * print_dir_entry(). memset is required only if mg_stat()
      * fails. For more details, see
      * http://code.google.com/p/mongoose/issues/detail?id=79 */
      memset(&de.file, 0, sizeof(de.file));

      if (truncated) {
        /* Do not delete anything shorter */
        ok = 0;
        continue;
      }

      if (!mg_stat(conn, path, &de.file)) {
        mg_cry(conn,
          "%s: mg_stat(%s) failed: %s",
          __func__,
          path,
          strerror(ERRNO));
        ok = 0;
      }
      if (de.file.membuf == NULL) {
        /* file is not in memory */
        if (de.file.is_directory) {
          if (remove_directory(conn, path) == 0) {
            ok = 0;
          }
        }
        else {
          if (mg_remove(path) == 0) {
            ok = 0;
          }
        }
      }
      else {
        /* file is in memory. It can not be deleted. */
        ok = 0;
      }
    }
    (void)closedir(dirp);

    IGNORE_UNUSED_RESULT(rmdir(dir));
  }

  return ok;
}
#endif

struct dir_scan_data {
  struct de *entries;
  unsigned int num_entries;
  unsigned int arr_size;
};


/* Behaves like realloc(), but frees original pointer on failure */
static void *
realloc2(void *ptr, size_t size)
{
  void *new_ptr = mg_realloc(ptr, size);
  if (new_ptr == NULL) {
    mg_free(ptr);
  }
  return new_ptr;
}


static void
dir_scan_callback(struct de *de, void *data)
{
  struct dir_scan_data *dsd = (struct dir_scan_data *)data;

  if (dsd->entries == NULL || dsd->num_entries >= dsd->arr_size) {
    dsd->arr_size *= 2;
    dsd->entries =
      (struct de *)realloc2(dsd->entries,
        dsd->arr_size * sizeof(dsd->entries[0]));
  }
  if (dsd->entries == NULL) {
    /* TODO(lsm, low): propagate an error to the caller */
    dsd->num_entries = 0;
  }
  else {
    dsd->entries[dsd->num_entries].file_name = mg_strdup(de->file_name);
    dsd->entries[dsd->num_entries].file = de->file;
    dsd->entries[dsd->num_entries].conn = de->conn;
    dsd->num_entries++;
  }
}


static void
handle_directory_request(struct mg_connection *conn, const char *dir)
{
  unsigned int i;
  int sort_direction;
  struct dir_scan_data data = { NULL, 0, 128 };
  char date[64];
  time_t curtime = time(NULL);

  if (!scan_directory(conn, dir, &data, dir_scan_callback)) {
    send_http_error(conn,
      500,
      "Error: Cannot open directory\nopendir(%s): %s",
      dir,
      strerror(ERRNO));
    return;
  }

  gmt_time_string(date, sizeof(date), &curtime);

  if (!conn) {
    return;
  }

  sort_direction = conn->request_info.query_string != NULL
    && conn->request_info.query_string[1] == 'd'
    ? 'a'
    : 'd';

  conn->must_close = 1;
  mg_printf(conn, "HTTP/1.1 200 OK\r\n");
  send_static_cache_header(conn);
  mg_printf(conn,
    "Date: %s\r\n"
    "Connection: close\r\n"
    "Content-Type: text/html; charset=utf-8\r\n\r\n",
    date);

  conn->num_bytes_sent +=
    mg_printf(conn,
      "<html><head><title>Index of %s</title>"
      "<style>th {text-align: left;}</style></head>"
      "<body><h1>Index of %s</h1><pre><table cellpadding=\"0\">"
      "<tr><th><a href=\"?n%c\">Name</a></th>"
      "<th><a href=\"?d%c\">Modified</a></th>"
      "<th><a href=\"?s%c\">Size</a></th></tr>"
      "<tr><td colspan=\"3\"><hr></td></tr>",
      conn->request_info.local_uri,
      conn->request_info.local_uri,
      sort_direction,
      sort_direction,
      sort_direction);

  /* Print first entry - link to a parent directory */
  conn->num_bytes_sent +=
    mg_printf(conn,
      "<tr><td><a href=\"%s%s\">%s</a></td>"
      "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
      conn->request_info.local_uri,
      "..",
      "Parent directory",
      "-",
      "-");

  /* Sort and print directory entries */
  if (data.entries != NULL) {
    qsort(data.entries,
      (size_t)data.num_entries,
      sizeof(data.entries[0]),
      compare_dir_entries);
    for (i = 0; i < data.num_entries; i++) {
      print_dir_entry(&data.entries[i]);
      mg_free(data.entries[i].file_name);
    }
    mg_free(data.entries);
  }

  conn->num_bytes_sent += mg_printf(conn, "%s", "</table></body></html>");
  conn->status_code = 200;
}


/* Send len bytes from the opened file to the client. */
static void
send_file_data(struct mg_connection *conn,
struct file *filep,
  int64_t offset,
  int64_t len)
{
  char buf[MG_BUF_LEN];
  int to_read, num_read, num_written;
  int64_t size;

  if (!filep || !conn) {
    return;
  }

  /* Sanity check the offset */
  size = filep->size > INT64_MAX ? INT64_MAX : (int64_t)(filep->size);
  offset = offset < 0 ? 0 : offset > size ? size : offset;

  if (len > 0 && filep->membuf != NULL && size > 0) {
    /* file stored in memory */
    if (len > size - offset) {
      len = size - offset;
    }
    mg_write(conn, filep->membuf + offset, (size_t)len);
  }
  else if (len > 0 && filep->fp != NULL) {
    /* file stored on disk */
#if defined(__linux__)
    /* sendfile is only available for Linux */
    if (conn->throttle == 0 && conn->ssl == 0) {
      off_t sf_offs = (off_t)offset;
      ssize_t sf_sent;
      int sf_file = fileno(filep->fp);
      int loop_cnt = 0;

      do {
        /* 2147479552 (0x7FFFF000) is a limit found by experiment on
        * 64 bit Linux (2^31 minus one memory page of 4k?). */
        size_t sf_tosend =
          (size_t)((len < 0x7FFFF000) ? len : 0x7FFFF000);
        sf_sent =
          sendfile(conn->client.sock, sf_file, &sf_offs, sf_tosend);
        if (sf_sent > 0) {
          conn->num_bytes_sent += sf_sent;
          len -= sf_sent;
          offset += sf_sent;
        }
        else if (loop_cnt == 0) {
          /* This file can not be sent using sendfile.
          * This might be the case for pseudo-files in the
          * /sys/ and /proc/ file system.
          * Use the regular user mode copy code instead. */
          break;
        }
        else if (sf_sent == 0) {
          /* No error, but 0 bytes sent. May be EOF? */
          return;
        }
        loop_cnt++;

      } while ((len > 0) && (sf_sent >= 0));

      if (sf_sent > 0) {
        return; /* OK */
      }

      /* sf_sent<0 means error, thus fall back to the classic way */
      /* This is always the case, if sf_file is not a "normal" file,
      * e.g., for sending data from the output of a CGI process. */
      offset = (int64_t)sf_offs;
    }
#endif
    if ((offset > 0) && (fseeko(filep->fp, offset, SEEK_SET) != 0)) {
      mg_cry(conn, "%s: fseeko() failed: %s", __func__, strerror(ERRNO));
      send_http_error(
        conn,
        500,
        "%s",
        "Error: Unable to access file at requested position.");
    }
    else {
      while (len > 0) {
        /* Calculate how much to read from the file in the buffer */
        to_read = sizeof(buf);
        if ((int64_t)to_read > len) {
          to_read = (int)len;
        }

        /* Read from file, exit the loop on error */
        if ((num_read = (int)fread(buf, 1, (size_t)to_read, filep->fp))
          <= 0) {
          break;
        }

        /* Send read bytes to the client, exit the loop on error */
        if ((num_written = mg_write(conn, buf, (size_t)num_read))
          != num_read) {
          break;
        }

        /* Both read and were successful, adjust counters */
        conn->num_bytes_sent += num_written;
        len -= num_written;
      }
    }
  }
}


static int
parse_range_header(const char *header, int64_t *a, int64_t *b)
{
  return sscanf(header, "bytes=%" INT64_FMT "-%" INT64_FMT, a, b);
}


static void
construct_etag(char *buf, size_t buf_len, const struct file *filep)
{
  if (filep != NULL && buf != NULL) {
    mg_snprintf(NULL,
      NULL, /* All calls to construct_etag use 64 byte buffer */
      buf,
      buf_len,
      "\"%lx.%" INT64_FMT "\"",
      (unsigned long)filep->last_modified,
      filep->size);
  }
}


static void
fclose_on_exec(struct file *filep, struct mg_connection *conn)
{
  if (filep != NULL && filep->fp != NULL) {
#ifdef _WIN32
    (void)conn; /* Unused. */
#else
    if (fcntl(fileno(filep->fp), F_SETFD, FD_CLOEXEC) != 0) {
      mg_cry(conn,
        "%s: fcntl(F_SETFD FD_CLOEXEC) failed: %s",
        __func__,
        strerror(ERRNO));
    }
#endif
  }
}


static void
handle_static_file_request(struct mg_connection *conn,
  const char *path,
struct file *filep,
  const char *mime_type)
{
  char date[64], lm[64], etag[64];
  char range[128]; /* large enough, so there will be no overflow */
  const char *msg = "OK", *hdr;
  time_t curtime = time(NULL);
  int64_t cl, r1, r2;
  struct vec mime_vec;
  int n, truncated;
  char gz_path[PATH_MAX];
  const char *encoding = "";
  const char *cors1, *cors2, *cors3;

  if (conn == NULL || conn->ctx == NULL || filep == NULL) {
    return;
  }

  if (mime_type == NULL) {
    get_mime_type(conn->ctx, path, &mime_vec);
  }
  else {
    mime_vec.ptr = mime_type;
    mime_vec.len = strlen(mime_type);
  }
  if (filep->size > INT64_MAX) {
    send_http_error(conn,
      500,
      "Error: File size is too large to send\n%" INT64_FMT,
      filep->size);
  }
  cl = (int64_t)filep->size;
  conn->status_code = 200;
  range[0] = '\0';

  /* if this file is in fact a pre-gzipped file, rewrite its filename
  * it's important to rewrite the filename after resolving
  * the mime type from it, to preserve the actual file's type */
  if (filep->gzipped) {
    mg_snprintf(conn, &truncated, gz_path, sizeof(gz_path), "%s.gz", path);

    if (truncated) {
      send_http_error(conn,
        500,
        "Error: Path of zipped file too long (%s)",
        path);
      return;
    }

    path = gz_path;
    encoding = "Content-Encoding: gzip\r\n";
  }

  if (!mg_fopen(conn, path, "rb", filep)) {
    send_http_error(conn,
      500,
      "Error: Cannot open file\nfopen(%s): %s",
      path,
      strerror(ERRNO));
    return;
  }

  fclose_on_exec(filep, conn);

  /* If Range: header specified, act accordingly */
  r1 = r2 = 0;
  hdr = mg_get_header(conn, "Range");
  if (hdr != NULL && (n = parse_range_header(hdr, &r1, &r2)) > 0 && r1 >= 0
    && r2 >= 0) {
    /* actually, range requests don't play well with a pre-gzipped
    * file (since the range is specified in the uncompressed space) */
    if (filep->gzipped) {
      send_http_error(
        conn,
        501,
        "%s",
        "Error: Range requests in gzipped files are not supported");
      mg_fclose(filep);
      return;
    }
    conn->status_code = 206;
    cl = n == 2 ? (r2 > cl ? cl : r2) - r1 + 1 : cl - r1;
    mg_snprintf(conn,
      NULL, /* range buffer is big enough */
      range,
      sizeof(range),
      "Content-Range: bytes "
      "%" INT64_FMT "-%" INT64_FMT "/%" INT64_FMT "\r\n",
      r1,
      r1 + cl - 1,
      filep->size);
    msg = "Partial Content";
  }

  hdr = mg_get_header(conn, "Origin");
  if (hdr) {
    /* Cross-origin resource sharing (CORS), see
    * http://www.html5rocks.com/en/tutorials/cors/,
    * http://www.html5rocks.com/static/images/cors_server_flowchart.png -
    * preflight is not supported for files. */
    cors1 = "Access-Control-Allow-Origin: ";
    cors2 = conn->ctx->config[ACCESS_CONTROL_ALLOW_ORIGIN];
    cors3 = "\r\n";
  }
  else {
    cors1 = cors2 = cors3 = "";
  }

  /* Prepare Etag, Date, Last-Modified headers. Must be in UTC, according to
  * http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.3 */
  gmt_time_string(date, sizeof(date), &curtime);
  gmt_time_string(lm, sizeof(lm), &filep->last_modified);
  construct_etag(etag, sizeof(etag), filep);

  (void)mg_printf(conn,
    "HTTP/1.1 %d %s\r\n"
    "%s%s%s"
    "Date: %s\r\n",
    conn->status_code,
    msg,
    cors1,
    cors2,
    cors3,
    date);
  send_static_cache_header(conn);
  (void)mg_printf(conn,
    "Last-Modified: %s\r\n"
    "Etag: %s\r\n"
    "Content-Type: %.*s\r\n"
    "Content-Length: %" INT64_FMT "\r\n"
    "Connection: %s\r\n"
    "Accept-Ranges: bytes\r\n"
    "%s%s\r\n",
    lm,
    etag,
    (int)mime_vec.len,
    mime_vec.ptr,
    cl,
    suggest_connection_header(conn),
    range,
    encoding);

  if (strcmp(conn->request_info.request_method, "HEAD") != 0) {
    send_file_data(conn, filep, r1, cl);
  }
  mg_fclose(filep);
}


void
mg_send_file(struct mg_connection *conn, const char *path)
{
  mg_send_mime_file(conn, path, NULL);
}

void
mg_send_mime_file(struct mg_connection *conn,
  const char *path,
  const char *mime_type)
{
  struct file file = STRUCT_FILE_INITIALIZER;
  if (mg_stat(conn, path, &file)) {
    if (file.is_directory) {
      if (!conn) {
        return;
      }
      if (!mg_strcasecmp(conn->ctx->config[ENABLE_DIRECTORY_LISTING],
        "yes")) {
        handle_directory_request(conn, path);
      }
      else {
        send_http_error(conn,
          403,
          "%s",
          "Error: Directory listing denied");
      }
    }
    else {
      handle_static_file_request(conn, path, &file, mime_type);
    }
  }
  else {
    send_http_error(conn, 404, "%s", "Error: File not found");
  }
}


/* For a given PUT path, create all intermediate subdirectories.
* Return  0  if the path itself is a directory.
* Return  1  if the path leads to a file.
* Return -1  for if the path is too long.
* Return -2  if path can not be created.
*/
static int
put_dir(struct mg_connection *conn, const char *path)
{
  char buf[PATH_MAX];
  const char *s, *p;
  struct file file = STRUCT_FILE_INITIALIZER;
  size_t len;
  int res = 1;

  for (s = p = path + 2; (p = strchr(s, '/')) != NULL; s = ++p) {
    len = (size_t)(p - path);
    if (len >= sizeof(buf)) {
      /* path too long */
      res = -1;
      break;
    }
    memcpy(buf, path, len);
    buf[len] = '\0';

    /* Try to create intermediate directory */
    DEBUG_TRACE("mkdir(%s)", buf);
    if (!mg_stat(conn, buf, &file) && mg_mkdir(buf, 0755) != 0) {
      /* path does not exixt and can not be created */
      res = -2;
      break;
    }

    /* Is path itself a directory? */
    if (p[1] == '\0') {
      res = 0;
    }
  }

  return res;
}


static void
remove_bad_file(const struct mg_connection *conn, const char *path)
{
  int r = mg_remove(path);
  if (r != 0) {
    mg_cry(conn, "%s: Cannot remove invalid file %s", __func__, path);
  }
}


long long
mg_store_body(struct mg_connection *conn, const char *path)
{
  char buf[MG_BUF_LEN];
  long long len = 0;
  int ret, n;
  struct file fi;

  if (conn->consumed_content != 0) {
    mg_cry(conn, "%s: Contents already consumed", __func__);
    return -11;
  }

  ret = put_dir(conn, path);
  if (ret < 0) {
    /* -1 for path too long,
    * -2 for path can not be created. */
    return ret;
  }
  if (ret != 1) {
    /* Return 0 means, path itself is a directory. */
    return 0;
  }

  if (mg_fopen(conn, path, "w", &fi) == 0) {
    return -12;
  }

  ret = mg_read(conn, buf, sizeof(buf));
  while (ret > 0) {
    n = (int)fwrite(buf, 1, (size_t)ret, fi.fp);
    if (n != ret) {
      fclose(fi.fp);
      remove_bad_file(conn, path);
      return -13;
    }
    ret = mg_read(conn, buf, sizeof(buf));
  }

  /* TODO: mg_fclose should return an error,
  * and every caller should check and handle it. */
  if (fclose(fi.fp) != 0) {
    remove_bad_file(conn, path);
    return -14;
  }

  return len;
}


/* Parse HTTP headers from the given buffer, advance buffer to the point
* where parsing stopped. */
static void
parse_http_headers(char **buf, struct mg_request_info *ri)
{
  int i;

  if (!ri) {
    return;
  }

  ri->num_headers = 0;

  for (i = 0; i < (int)ARRAY_SIZE(ri->http_headers); i++) {
    char *dp = *buf;
    while ((*dp != ':') && (*dp != '\r') && (*dp != 0)) {
      dp++;
    }
    if (!*dp) {
      /* neither : nor \r\n. This is not a valid field. */
      break;
    }
    if (*dp == '\r') {
      if (dp[1] == '\n') {
        /* \r\n */
        ri->http_headers[i].name = *buf;
        ri->http_headers[i].value = 0;
        *buf = dp;
      }
      else {
        /* stray \r. This is not valid. */
        break;
      }
    }
    else {
      /* (*dp == ':') */
      *dp = 0;
      ri->http_headers[i].name = *buf;
      do {
        dp++;
      } while (*dp == ' ');

      ri->http_headers[i].value = dp;
      *buf = strstr(dp, "\r\n");
    }

    ri->num_headers = i + 1;
    if (*buf) {
      (*buf)[0] = 0;
      (*buf)[1] = 0;
      *buf += 2;
    }
    else {
      *buf = dp;
      break;
    }

    if (*buf[0] == '\r') {
      /* This is the end of the header */
      break;
    }
  }
}


static int
is_valid_http_method(const char *method)
{
  return !strcmp(method, "GET")        /* HTTP (RFC 2616) */
    || !strcmp(method, "POST")    /* HTTP (RFC 2616) */
    || !strcmp(method, "HEAD")    /* HTTP (RFC 2616) */
    || !strcmp(method, "PUT")     /* HTTP (RFC 2616) */
    || !strcmp(method, "DELETE")  /* HTTP (RFC 2616) */
    || !strcmp(method, "OPTIONS") /* HTTP (RFC 2616) */
                                  /* TRACE method (RFC 2616) is not supported for security reasons */
    || !strcmp(method, "CONNECT") /* HTTP (RFC 2616) */

    || !strcmp(method, "PROPFIND") /* WEBDAV (RFC 2518) */
    || !strcmp(method, "MKCOL")    /* WEBDAV (RFC 2518) */

                                   /* Unsupported WEBDAV Methods: */
                                   /* PROPPATCH, COPY, MOVE, LOCK, UNLOCK (RFC 2518) */
                                   /* + 11 methods from RFC 3253 */
                                   /* ORDERPATCH (RFC 3648) */
                                   /* ACL (RFC 3744) */
                                   /* SEARCH (RFC 5323) */
                                   /* + MicroSoft extensions
                                   * https://msdn.microsoft.com/en-us/library/aa142917.aspx */

                                   /* PATCH method only allowed for CGI/Lua/LSP and callbacks. */
    || !strcmp(method, "PATCH"); /* PATCH method (RFC 5789) */
}


/* Parse HTTP request, fill in mg_request_info structure.
* This function modifies the buffer by NUL-terminating
* HTTP request components, header names and header values. */
static int
parse_http_message(char *buf, int len, struct mg_request_info *ri)
{
  int is_request, request_length;

  if (!ri) {
    return 0;
  }

  request_length = get_request_len(buf, len);

  if (request_length > 0) {
    /* Reset attributes. DO NOT TOUCH is_ssl, remote_ip, remote_addr,
    * remote_port */
    ri->remote_user = ri->request_method = ri->request_uri =
      ri->http_version = NULL;
    ri->num_headers = 0;

    buf[request_length - 1] = '\0';

    /* RFC says that all initial whitespaces should be ingored */
    while (*buf != '\0' && isspace(*(unsigned char *)buf)) {
      buf++;
    }
    ri->request_method = skip(&buf, " ");
    ri->request_uri = skip(&buf, " ");
    ri->http_version = skip(&buf, "\r\n");

    /* HTTP message could be either HTTP request or HTTP response, e.g.
    * "GET / HTTP/1.0 ...." or  "HTTP/1.0 200 OK ..." */
    is_request = is_valid_http_method(ri->request_method);
    if ((is_request && memcmp(ri->http_version, "HTTP/", 5) != 0)
      || (!is_request && memcmp(ri->request_method, "HTTP/", 5) != 0)) {
      request_length = -1;
    }
    else {
      if (is_request) {
        ri->http_version += 5;
      }
      parse_http_headers(&buf, ri);
    }
  }
  return request_length;
}


/* Keep reading the input (either opened file descriptor fd, or socket sock,
* or SSL descriptor ssl) into buffer buf, until \r\n\r\n appears in the
* buffer (which marks the end of HTTP request). Buffer buf may already
* have some data. The length of the data is stored in nread.
* Upon every read operation, increase nread by the number of bytes read. */
static int
read_request(FILE *fp,
struct mg_connection *conn,
  char *buf,
  int bufsiz,
  int *nread)
{
  int request_len, n = 0;
  struct timespec last_action_time;
  double request_timeout;

  if (!conn) {
    return 0;
  }

  memset(&last_action_time, 0, sizeof(last_action_time));

  if (conn->ctx->config[REQUEST_TIMEOUT]) {
    /* value of request_timeout is in seconds, config in milliseconds */
    request_timeout = atof(conn->ctx->config[REQUEST_TIMEOUT]) / 1000.0;
  }
  else {
    request_timeout = -1.0;
  }

  request_len = get_request_len(buf, *nread);

  /* first time reading from this connection */
  clock_gettime(CLOCK_MONOTONIC, &last_action_time);

  while (
    (conn->ctx->stop_flag == 0) && (*nread < bufsiz) && (request_len == 0)
    && ((mg_difftimespec(&last_action_time, &(conn->req_time))
      <= request_timeout) || (request_timeout < 0))
    && ((n = pull(fp, conn, buf + *nread, bufsiz - *nread, request_timeout))
      > 0)) {
    *nread += n;
    /* assert(*nread <= bufsiz); */
    if (*nread > bufsiz) {
      return -2;
    }
    request_len = get_request_len(buf, *nread);
    if (request_timeout > 0.0) {
      clock_gettime(CLOCK_MONOTONIC, &last_action_time);
    }
  }

  return (request_len <= 0 && n <= 0) ? -1 : request_len;
}

#if !defined(NO_FILES)
/* For given directory path, substitute it to valid index file.
* Return 1 if index file has been found, 0 if not found.
* If the file is found, it's stats is returned in stp. */
static int
substitute_index_file(struct mg_connection *conn,
  char *path,
  size_t path_len,
struct file *filep)
{
  if (conn && conn->ctx) {
    const char *list = conn->ctx->config[INDEX_FILES];
    struct file file = STRUCT_FILE_INITIALIZER;
    struct vec filename_vec;
    size_t n = strlen(path);
    int found = 0;

    /* The 'path' given to us points to the directory. Remove all trailing
    * directory separator characters from the end of the path, and
    * then append single directory separator character. */
    while (n > 0 && path[n - 1] == '/') {
      n--;
    }
    path[n] = '/';

    /* Traverse index files list. For each entry, append it to the given
    * path and see if the file exists. If it exists, break the loop */
    while ((list = next_option(list, &filename_vec, NULL)) != NULL) {
      /* Ignore too long entries that may overflow path buffer */
      if (filename_vec.len > path_len - (n + 2)) {
        continue;
      }

      /* Prepare full path to the index file */
      mg_strlcpy(path + n + 1, filename_vec.ptr, filename_vec.len + 1);

      /* Does it exist? */
      if (mg_stat(conn, path, &file)) {
        /* Yes it does, break the loop */
        *filep = file;
        found = 1;
        break;
      }
    }

    /* If no index file exists, restore directory path */
    if (!found) {
      path[n] = '\0';
    }

    return found;
  }
  return 0;
}
#endif


/* Return True if we should reply 304 Not Modified. */
static int
is_not_modified(const struct mg_connection *conn, const struct file *filep)
{
  char etag[64];
  const char *ims = mg_get_header(conn, "If-Modified-Since");
  const char *inm = mg_get_header(conn, "If-None-Match");
  construct_etag(etag, sizeof(etag), filep);
  if (!filep) {
    return 0;
  }
  return (inm != NULL && !mg_strcasecmp(etag, inm))
    || (ims != NULL && (filep->last_modified <= parse_date_string(ims)));
}


#if !defined(NO_CGI) || !defined(NO_FILES)
static int
forward_body_data(struct mg_connection *conn, FILE *fp, SOCKET sock, SSL *ssl)
{
  const char *expect, *body;
  char buf[MG_BUF_LEN];
  int to_read, nread, success = 0;
  int64_t buffered_len;
  double timeout = -1.0;

  if (!conn) {
    return 0;
  }
  if (conn->ctx->config[REQUEST_TIMEOUT]) {
    timeout = atoi(conn->ctx->config[REQUEST_TIMEOUT]) / 1000.0;
  }

  expect = mg_get_header(conn, "Expect");
  /* assert(fp != NULL); */
  if (!fp) {
    send_http_error(conn, 500, "%s", "Error: NULL File");
    return 0;
  }

  if (conn->content_len == -1 && !conn->is_chunked) {
    /* Content length is not specified by the client. */
    send_http_error(conn,
      411,
      "%s",
      "Error: Client did not specify content length");
  }
  else if ((expect != NULL)
    && (mg_strcasecmp(expect, "100-continue") != 0)) {
    /* Client sent an "Expect: xyz" header and xyz is not 100-continue. */
    send_http_error(conn,
      417,
      "Error: Can not fulfill expectation %s",
      expect);
  }
  else {
    if (expect != NULL) {
      (void)mg_printf(conn, "%s", "HTTP/1.1 100 Continue\r\n\r\n");
      conn->status_code = 100;
    }
    else {
      conn->status_code = 200;
    }

    buffered_len = (int64_t)(conn->data_len) - (int64_t)conn->request_len
      - conn->consumed_content;

    /* assert(buffered_len >= 0); */
    /* assert(conn->consumed_content == 0); */

    if ((buffered_len < 0) || (conn->consumed_content != 0)) {
      send_http_error(conn, 500, "%s", "Error: Size mismatch");
      return 0;
    }

    if (buffered_len > 0) {
      if ((int64_t)buffered_len > conn->content_len) {
        buffered_len = (int)conn->content_len;
      }
      body = conn->buf + conn->request_len + conn->consumed_content;
      push_all(conn->ctx, fp, sock, ssl, body, (int64_t)buffered_len);
      conn->consumed_content += buffered_len;
    }

    nread = 0;
    while (conn->consumed_content < conn->content_len) {
      to_read = sizeof(buf);
      if ((int64_t)to_read > conn->content_len - conn->consumed_content) {
        to_read = (int)(conn->content_len - conn->consumed_content);
      }
      nread = pull(NULL, conn, buf, to_read, timeout);
      if (nread <= 0
        || push_all(conn->ctx, fp, sock, ssl, buf, nread) != nread) {
        break;
      }
      conn->consumed_content += nread;
    }

    if (conn->consumed_content == conn->content_len) {
      success = (nread >= 0);
    }

    /* Each error code path in this function must send an error */
    if (!success) {
      /* NOTE: Maybe some data has already been sent. */
      /* TODO (low): If some data has been sent, a correct error
      * reply can no longer be sent, so just close the connection */
      send_http_error(conn, 500, "%s", "");
    }
  }

  return success;
}
#endif

#if !defined(NO_CGI)
/* This structure helps to create an environment for the spawned CGI program.
* Environment is an array of "VARIABLE=VALUE\0" ASCIIZ strings,
* last element must be NULL.
* However, on Windows there is a requirement that all these VARIABLE=VALUE\0
* strings must reside in a contiguous buffer. The end of the buffer is
* marked by two '\0' characters.
* We satisfy both worlds: we create an envp array (which is vars), all
* entries are actually pointers inside buf. */
struct cgi_environment {
  struct mg_connection *conn;
  /* Data block */
  char *buf;      /* Environment buffer */
  size_t buflen;  /* Space available in buf */
  size_t bufused; /* Space taken in buf */
                  /* Index block */
  char **var;     /* char **envp */
  size_t varlen;  /* Number of variables available in var */
  size_t varused; /* Number of variables stored in var */
};


static void addenv(struct cgi_environment *env,
  PRINTF_FORMAT_STRING(const char *fmt),
  ...) PRINTF_ARGS(2, 3);

/* Append VARIABLE=VALUE\0 string to the buffer, and add a respective
* pointer into the vars array. Assumes env != NULL and fmt != NULL. */
static void
addenv(struct cgi_environment *env, const char *fmt, ...)
{
  size_t n, space;
  int truncated;
  char *added;
  va_list ap;

  /* Calculate how much space is left in the buffer */
  space = (env->buflen - env->bufused);

  /* Calculate an estimate for the required space */
  n = strlen(fmt) + 2 + 128;

  do {
    if (space <= n) {
      /* Allocate new buffer */
      n = env->buflen + CGI_ENVIRONMENT_SIZE;
      added = (char *)mg_realloc(env->buf, n);
      if (!added) {
        /* Out of memory */
        mg_cry(env->conn,
          "%s: Cannot allocate memory for CGI variable [%s]",
          __func__,
          fmt);
        return;
      }
      env->buf = added;
      env->buflen = n;
      space = (env->buflen - env->bufused);
    }

    /* Make a pointer to the free space int the buffer */
    added = env->buf + env->bufused;

    /* Copy VARIABLE=VALUE\0 string into the free space */
    va_start(ap, fmt);
    mg_vsnprintf(env->conn, &truncated, added, (size_t)space, fmt, ap);
    va_end(ap);

    /* Do not add truncated strings to the environment */
    if (truncated) {
      /* Reallocate the buffer */
      space = 0;
      n = 1;
    }
  } while (truncated);

  /* Calculate number of bytes added to the environment */
  n = strlen(added) + 1;
  env->bufused += n;

  /* Now update the variable index */
  space = (env->varlen - env->varused);
  if (space < 2) {
    mg_cry(env->conn,
      "%s: Cannot register CGI variable [%s]",
      __func__,
      fmt);
    return;
  }

  /* Append a pointer to the added string into the envp array */
  env->var[env->varused] = added;
  env->varused++;
}


static void
prepare_cgi_environment(struct mg_connection *conn,
  const char *prog,
struct cgi_environment *env)
{
  const char *s;
  struct vec var_vec;
  char *p, src_addr[IP_ADDR_STR_LEN], http_var_name[128];
  int i, truncated;

  if (conn == NULL || prog == NULL || env == NULL) {
    return;
  }

  env->conn = conn;
  env->buflen = CGI_ENVIRONMENT_SIZE;
  env->bufused = 0;
  env->buf = (char *)mg_malloc(env->buflen);
  env->varlen = MAX_CGI_ENVIR_VARS;
  env->varused = 0;
  env->var = (char **)mg_malloc(env->buflen * sizeof(char *));

  addenv(env, "SERVER_NAME=%s", conn->ctx->config[AUTHENTICATION_DOMAIN]);
  addenv(env, "SERVER_ROOT=%s", conn->ctx->config[DOCUMENT_ROOT]);
  addenv(env, "DOCUMENT_ROOT=%s", conn->ctx->config[DOCUMENT_ROOT]);
  addenv(env, "SERVER_SOFTWARE=%s/%s", "Civetweb", mg_version());

  /* Prepare the environment block */
  addenv(env, "%s", "GATEWAY_INTERFACE=CGI/1.1");
  addenv(env, "%s", "SERVER_PROTOCOL=HTTP/1.1");
  addenv(env, "%s", "REDIRECT_STATUS=200"); /* For PHP */

#if defined(USE_IPV6)
  if (conn->client.lsa.sa.sa_family == AF_INET6) {
    addenv(env, "SERVER_PORT=%d", ntohs(conn->client.lsa.sin6.sin6_port));
  }
  else
#endif
  {
    addenv(env, "SERVER_PORT=%d", ntohs(conn->client.lsa.sin.sin_port));
  }

  sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
  addenv(env, "REMOTE_ADDR=%s", src_addr);

  addenv(env, "REQUEST_METHOD=%s", conn->request_info.request_method);
  addenv(env, "REMOTE_PORT=%d", conn->request_info.remote_port);

  addenv(env, "REQUEST_URI=%s", conn->request_info.request_uri);
  addenv(env, "LOCAL_URI=%s", conn->request_info.local_uri);

  /* SCRIPT_NAME */
  addenv(env,
    "SCRIPT_NAME=%.*s",
    (int)strlen(conn->request_info.local_uri)
    - ((conn->path_info == NULL) ? 0 : (int)strlen(conn->path_info)),
    conn->request_info.local_uri);

  addenv(env, "SCRIPT_FILENAME=%s", prog);
  if (conn->path_info == NULL) {
    addenv(env, "PATH_TRANSLATED=%s", conn->ctx->config[DOCUMENT_ROOT]);
  }
  else {
    addenv(env,
      "PATH_TRANSLATED=%s%s",
      conn->ctx->config[DOCUMENT_ROOT],
      conn->path_info);
  }

  addenv(env, "HTTPS=%s", conn->ssl == NULL ? "off" : "on");

  if ((s = mg_get_header(conn, "Content-Type")) != NULL) {
    addenv(env, "CONTENT_TYPE=%s", s);
  }
  if (conn->request_info.query_string != NULL) {
    addenv(env, "QUERY_STRING=%s", conn->request_info.query_string);
  }
  if ((s = mg_get_header(conn, "Content-Length")) != NULL) {
    addenv(env, "CONTENT_LENGTH=%s", s);
  }
  if ((s = getenv("PATH")) != NULL) {
    addenv(env, "PATH=%s", s);
  }
  if (conn->path_info != NULL) {
    addenv(env, "PATH_INFO=%s", conn->path_info);
  }

  if (conn->status_code > 0) {
    /* CGI error handler should show the status code */
    addenv(env, "STATUS=%d", conn->status_code);
  }

#if defined(_WIN32)
  if ((s = getenv("COMSPEC")) != NULL) {
    addenv(env, "COMSPEC=%s", s);
  }
  if ((s = getenv("SYSTEMROOT")) != NULL) {
    addenv(env, "SYSTEMROOT=%s", s);
  }
  if ((s = getenv("SystemDrive")) != NULL) {
    addenv(env, "SystemDrive=%s", s);
  }
  if ((s = getenv("ProgramFiles")) != NULL) {
    addenv(env, "ProgramFiles=%s", s);
  }
  if ((s = getenv("ProgramFiles(x86)")) != NULL) {
    addenv(env, "ProgramFiles(x86)=%s", s);
  }
#else
  if ((s = getenv("LD_LIBRARY_PATH")) != NULL) {
    addenv(env, "LD_LIBRARY_PATH=%s", s);
  }
#endif /* _WIN32 */

  if ((s = getenv("PERLLIB")) != NULL) {
    addenv(env, "PERLLIB=%s", s);
  }

  if (conn->request_info.remote_user != NULL) {
    addenv(env, "REMOTE_USER=%s", conn->request_info.remote_user);
    addenv(env, "%s", "AUTH_TYPE=Digest");
  }

  /* Add all headers as HTTP_* variables */
  for (i = 0; i < conn->request_info.num_headers; i++) {

    (void)mg_snprintf(conn,
      &truncated,
      http_var_name,
      sizeof(http_var_name),
      "HTTP_%s",
      conn->request_info.http_headers[i].name);

    if (truncated) {
      mg_cry(conn,
        "%s: HTTP header variable too long [%s]",
        __func__,
        conn->request_info.http_headers[i].name);
      continue;
    }

    /* Convert variable name into uppercase, and change - to _ */
    for (p = http_var_name; *p != '\0'; p++) {
      if (*p == '-') {
        *p = '_';
      }
      *p = (char)toupper(*(unsigned char *)p);
    }

    addenv(env,
      "%s=%s",
      http_var_name,
      conn->request_info.http_headers[i].value);
  }

  /* Add user-specified variables */
  s = conn->ctx->config[CGI_ENVIRONMENT];
  while ((s = next_option(s, &var_vec, NULL)) != NULL) {
    addenv(env, "%.*s", (int)var_vec.len, var_vec.ptr);
  }

  env->var[env->varused] = NULL;
  env->buf[env->bufused] = '\0';
}


static void
handle_cgi_request(struct mg_connection *conn, const char *prog)
{
  char *buf;
  size_t buflen;
  int headers_len, data_len, i, truncated;
  int fdin[2] = { -1, -1 }, fdout[2] = { -1, -1 }, fderr[2] = { -1, -1 };
  const char *status, *status_text, *connection_state;
  char *pbuf, dir[PATH_MAX], *p;
  struct mg_request_info ri;
  struct cgi_environment blk;
  FILE *in = NULL, *out = NULL, *err = NULL;
  struct file fout = STRUCT_FILE_INITIALIZER;
  pid_t pid = (pid_t)-1;

  if (conn == NULL) {
    return;
  }

  buf = NULL;
  buflen = 16384;
  prepare_cgi_environment(conn, prog, &blk);

  /* CGI must be executed in its own directory. 'dir' must point to the
  * directory containing executable program, 'p' must point to the
  * executable program name relative to 'dir'. */
  (void)mg_snprintf(conn, &truncated, dir, sizeof(dir), "%s", prog);

  if (truncated) {
    mg_cry(conn, "Error: CGI program \"%s\": Path too long", prog);
    send_http_error(conn, 500, "Error: %s", "CGI path too long");
    goto done;
  }

  if ((p = strrchr(dir, '/')) != NULL) {
    *p++ = '\0';
  }
  else {
    dir[0] = '.', dir[1] = '\0';
    p = (char *)prog;
  }

  if (pipe(fdin) != 0 || pipe(fdout) != 0 || pipe(fderr) != 0) {
    status = strerror(ERRNO);
    mg_cry(conn,
      "Error: CGI program \"%s\": Can not create CGI pipes: %s",
      prog,
      status);
    send_http_error(conn, 500, "Error: Cannot create CGI pipe: %s", status);
    goto done;
  }

  pid = spawn_process(
    conn, p, blk.buf, blk.var, fdin[0], fdout[1], fderr[1], dir);

  if (pid == (pid_t)-1) {
    status = strerror(ERRNO);
    mg_cry(conn,
      "Error: CGI program \"%s\": Can not spawn CGI process: %s",
      prog,
      status);
    send_http_error(conn,
      500,
      "Error: Cannot spawn CGI process [%s]: %s",
      prog,
      status);
    goto done;
  }

  /* Make sure child closes all pipe descriptors. It must dup them to 0,1 */
  set_close_on_exec((SOCKET)fdin[0], conn);
  set_close_on_exec((SOCKET)fdin[1], conn);
  set_close_on_exec((SOCKET)fdout[0], conn);
  set_close_on_exec((SOCKET)fdout[1], conn);
  set_close_on_exec((SOCKET)fderr[0], conn);
  set_close_on_exec((SOCKET)fderr[1], conn);

  /* Parent closes only one side of the pipes.
  * If we don't mark them as closed, close() attempt before
  * return from this function throws an exception on Windows.
  * Windows does not like when closed descriptor is closed again. */
  (void)close(fdin[0]);
  (void)close(fdout[1]);
  (void)close(fderr[1]);
  fdin[0] = fdout[1] = fderr[1] = -1;

  if ((in = fdopen(fdin[1], "wb")) == NULL) {
    status = strerror(ERRNO);
    mg_cry(conn,
      "Error: CGI program \"%s\": Can not open stdin: %s",
      prog,
      status);
    send_http_error(conn,
      500,
      "Error: CGI can not open fdin\nfopen: %s",
      status);
    goto done;
  }

  if ((out = fdopen(fdout[0], "rb")) == NULL) {
    status = strerror(ERRNO);
    mg_cry(conn,
      "Error: CGI program \"%s\": Can not open stdout: %s",
      prog,
      status);
    send_http_error(conn,
      500,
      "Error: CGI can not open fdout\nfopen: %s",
      status);
    goto done;
  }

  if ((err = fdopen(fderr[0], "rb")) == NULL) {
    status = strerror(ERRNO);
    mg_cry(conn,
      "Error: CGI program \"%s\": Can not open stderr: %s",
      prog,
      status);
    send_http_error(conn,
      500,
      "Error: CGI can not open fdout\nfopen: %s",
      status);
    goto done;
  }

  setbuf(in, NULL);
  setbuf(out, NULL);
  setbuf(err, NULL);
  fout.fp = out;

  if ((conn->request_info.content_length > 0) || conn->is_chunked) {
    /* This is a POST/PUT request, or another request with body data. */
    if (!forward_body_data(conn, in, INVALID_SOCKET, NULL)) {
      /* Error sending the body data */
      mg_cry(conn,
        "Error: CGI program \"%s\": Forward body data failed",
        prog);
      goto done;
    }
  }

  /* Close so child gets an EOF. */
  fclose(in);
  in = NULL;
  fdin[1] = -1;

  /* Now read CGI reply into a buffer. We need to set correct
  * status code, thus we need to see all HTTP headers first.
  * Do not send anything back to client, until we buffer in all
  * HTTP headers. */
  data_len = 0;
  buf = (char *)mg_malloc(buflen);
  if (buf == NULL) {
    send_http_error(conn,
      500,
      "Error: Not enough memory for CGI buffer (%u bytes)",
      (unsigned int)buflen);
    mg_cry(conn,
      "Error: CGI program \"%s\": Not enough memory for buffer (%u "
      "bytes)",
      prog,
      (unsigned int)buflen);
    goto done;
  }
  headers_len = read_request(out, conn, buf, (int)buflen, &data_len);
  if (headers_len <= 0) {

    /* Could not parse the CGI response. Check if some error message on
    * stderr. */
    i = pull_all(err, conn, buf, (int)buflen);
    if (i > 0) {
      mg_cry(conn,
        "Error: CGI program \"%s\" sent error "
        "message: [%.*s]",
        prog,
        i,
        buf);
      send_http_error(conn,
        500,
        "Error: CGI program \"%s\" sent error "
        "message: [%.*s]",
        prog,
        i,
        buf);
    }
    else {
      mg_cry(conn,
        "Error: CGI program sent malformed or too big "
        "(>%u bytes) HTTP headers: [%.*s]",
        (unsigned)buflen,
        data_len,
        buf);

      send_http_error(conn,
        500,
        "Error: CGI program sent malformed or too big "
        "(>%u bytes) HTTP headers: [%.*s]",
        (unsigned)buflen,
        data_len,
        buf);
    }

    goto done;
  }
  pbuf = buf;
  buf[headers_len - 1] = '\0';
  parse_http_headers(&pbuf, &ri);

  /* Make up and send the status line */
  status_text = "OK";
  if ((status = get_header(&ri, "Status")) != NULL) {
    conn->status_code = atoi(status);
    status_text = status;
    while (isdigit(*(unsigned char *)status_text) || *status_text == ' ') {
      status_text++;
    }
  }
  else if (get_header(&ri, "Location") != NULL) {
    conn->status_code = 302;
  }
  else {
    conn->status_code = 200;
  }
  connection_state = get_header(&ri, "Connection");
  if (connection_state == NULL
    || mg_strcasecmp(connection_state, "keep-alive")) {
    conn->must_close = 1;
  }
  (void)mg_printf(conn, "HTTP/1.1 %d %s\r\n", conn->status_code, status_text);

  /* Send headers */
  for (i = 0; i < ri.num_headers; i++) {
    mg_printf(conn,
      "%s: %s\r\n",
      ri.http_headers[i].name,
      ri.http_headers[i].value);
  }
  mg_write(conn, "\r\n", 2);

  /* Send chunk of data that may have been read after the headers */
  conn->num_bytes_sent +=
    mg_write(conn, buf + headers_len, (size_t)(data_len - headers_len));

  /* Read the rest of CGI output and send to the client */
  send_file_data(conn, &fout, 0, INT64_MAX);

done:
  mg_free(blk.var);
  mg_free(blk.buf);

  if (pid != (pid_t)-1) {
    kill(pid, SIGKILL);
#if !defined(_WIN32)
    {
      int st;
      while (waitpid(pid, &st, 0) != -1)
        ; /* clean zombies */
    }
#endif
  }
  if (fdin[0] != -1) {
    close(fdin[0]);
  }
  if (fdout[1] != -1) {
    close(fdout[1]);
  }

  if (in != NULL) {
    fclose(in);
  }
  else if (fdin[1] != -1) {
    close(fdin[1]);
  }

  if (out != NULL) {
    fclose(out);
  }
  else if (fdout[0] != -1) {
    close(fdout[0]);
  }

  if (err != NULL) {
    fclose(err);
  }
  else if (fderr[0] != -1) {
    close(fderr[0]);
  }

  if (buf != NULL) {
    mg_free(buf);
  }
}
#endif /* !NO_CGI */


#if !defined(NO_FILES)
static void
mkcol(struct mg_connection *conn, const char *path)
{
  int rc, body_len;
  struct de de;
  char date[64];
  time_t curtime = time(NULL);

  if (conn == NULL) {
    return;
  }

  /* TODO (mid): Check the send_http_error situations in this function */

  memset(&de.file, 0, sizeof(de.file));
  if (!mg_stat(conn, path, &de.file)) {
    mg_cry(conn,
      "%s: mg_stat(%s) failed: %s",
      __func__,
      path,
      strerror(ERRNO));
  }

  if (de.file.last_modified) {
    /* TODO (high): This check does not seem to make any sense ! */
    send_http_error(
      conn, 405, "Error: mkcol(%s): %s", path, strerror(ERRNO));
    return;
  }

  body_len = conn->data_len - conn->request_len;
  if (body_len > 0) {
    send_http_error(
      conn, 415, "Error: mkcol(%s): %s", path, strerror(ERRNO));
    return;
  }

  rc = mg_mkdir(path, 0755);

  if (rc == 0) {
    conn->status_code = 201;
    gmt_time_string(date, sizeof(date), &curtime);
    mg_printf(conn,
      "HTTP/1.1 %d Created\r\n"
      "Date: %s\r\n",
      conn->status_code,
      date);
    send_static_cache_header(conn);
    mg_printf(conn,
      "Content-Length: 0\r\n"
      "Connection: %s\r\n\r\n",
      suggest_connection_header(conn));
  }
  else if (rc == -1) {
    if (errno == EEXIST) {
      send_http_error(
        conn, 405, "Error: mkcol(%s): %s", path, strerror(ERRNO));
    }
    else if (errno == EACCES) {
      send_http_error(
        conn, 403, "Error: mkcol(%s): %s", path, strerror(ERRNO));
    }
    else if (errno == ENOENT) {
      send_http_error(
        conn, 409, "Error: mkcol(%s): %s", path, strerror(ERRNO));
    }
    else {
      send_http_error(conn, 500, "fopen(%s): %s", path, strerror(ERRNO));
    }
  }
}


static void
put_file(struct mg_connection *conn, const char *path)
{
  struct file file = STRUCT_FILE_INITIALIZER;
  const char *range;
  int64_t r1, r2;
  int rc;
  char date[64];
  time_t curtime = time(NULL);

  if (conn == NULL) {
    return;
  }

  if (mg_stat(conn, path, &file)) {
    /* File already exists */
    conn->status_code = 200;

    if (file.is_directory) {
      /* This is an already existing directory,
      * so there is nothing to do for the server. */
      rc = 0;

    }
    else {
      /* File exists and is not a directory. */
      /* Can it be replaced? */

      if (file.membuf != NULL) {
        /* This is an "in-memory" file, that can not be replaced */
        send_http_error(
          conn,
          405,
          "Error: Put not possible\nReplacing %s is not supported",
          path);
        return;
      }

      /* Check if the server may write this file */
      if (access(path, W_OK) == 0) {
        /* Access granted */
        conn->status_code = 200;
        rc = 1;
      }
      else {
        send_http_error(
          conn,
          403,
          "Error: Put not possible\nReplacing %s is not allowed",
          path);
        return;
      }
    }
  }
  else {
    /* File should be created */
    conn->status_code = 201;
    rc = put_dir(conn, path);
  }

  if (rc == 0) {
    /* put_dir returns 0 if path is a directory */
    gmt_time_string(date, sizeof(date), &curtime);
    mg_printf(conn,
      "HTTP/1.1 %d %s\r\n",
      conn->status_code,
      mg_get_response_code_text(conn->status_code, NULL));
    send_no_cache_header(conn);
    mg_printf(conn,
      "Date: %s\r\n"
      "Content-Length: 0\r\n"
      "Connection: %s\r\n\r\n",
      date,
      suggest_connection_header(conn));

    /* Request to create a directory has been fulfilled successfully.
    * No need to put a file. */
    return;
  }

  if (rc == -1) {
    /* put_dir returns -1 if the path is too long */
    send_http_error(conn,
      414,
      "Error: Path too long\nput_dir(%s): %s",
      path,
      strerror(ERRNO));
    return;
  }

  if (rc == -2) {
    /* put_dir returns -2 if the directory can not be created */
    send_http_error(conn,
      500,
      "Error: Can not create directory\nput_dir(%s): %s",
      path,
      strerror(ERRNO));
    return;
  }

  /* A file should be created or overwritten. */
  if (!mg_fopen(conn, path, "wb+", &file) || file.fp == NULL) {
    mg_fclose(&file);
    send_http_error(conn,
      500,
      "Error: Can not create file\nfopen(%s): %s",
      path,
      strerror(ERRNO));
    return;
  }

  fclose_on_exec(&file, conn);
  range = mg_get_header(conn, "Content-Range");
  r1 = r2 = 0;
  if (range != NULL && parse_range_header(range, &r1, &r2) > 0) {
    conn->status_code = 206; /* Partial content */
    fseeko(file.fp, r1, SEEK_SET);
  }

  if (!forward_body_data(conn, file.fp, INVALID_SOCKET, NULL)) {
    /* forward_body_data failed.
    * The error code has already been sent to the client,
    * and conn->status_code is already set. */
    mg_fclose(&file);
    return;
  }

  gmt_time_string(date, sizeof(date), &curtime);
  mg_printf(conn,
    "HTTP/1.1 %d %s\r\n",
    conn->status_code,
    mg_get_response_code_text(conn->status_code, NULL));
  send_no_cache_header(conn);
  mg_printf(conn,
    "Date: %s\r\n"
    "Content-Length: 0\r\n"
    "Connection: %s\r\n\r\n",
    date,
    suggest_connection_header(conn));

  mg_fclose(&file);
}


static void
delete_file(struct mg_connection *conn, const char *path)
{
  struct de de;
  memset(&de.file, 0, sizeof(de.file));
  if (!mg_stat(conn, path, &de.file)) {
    /* mg_stat returns 0 if the file does not exist */
    send_http_error(conn,
      404,
      "Error: Cannot delete file\nFile %s not found",
      path);
    return;
  }

  if (de.file.membuf != NULL) {
    /* the file is cached in memory */
    send_http_error(
      conn,
      405,
      "Error: Delete not possible\nDeleting %s is not supported",
      path);
    return;
  }

  if (de.file.is_directory) {
    if (remove_directory(conn, path)) {
      /* Delete is successful: Return 204 without content. */
      send_http_error(conn, 204, "%s", "");
    }
    else {
      /* Delete is not successful: Return 500 (Server error). */
      send_http_error(conn, 500, "Error: Could not delete %s", path);
    }
    return;
  }

  /* This is an existing file (not a directory).
  * Check if write permission is granted. */
  if (access(path, W_OK) != 0) {
    /* File is read only */
    send_http_error(
      conn,
      403,
      "Error: Delete not possible\nDeleting %s is not allowed",
      path);
    return;
  }

  /* Try to delete it. */
  if (mg_remove(path) == 0) {
    /* Delete was successful: Return 204 without content. */
    send_http_error(conn, 204, "%s", "");
  }
  else {
    /* Delete not successful (file locked). */
    send_http_error(conn,
      423,
      "Error: Cannot delete file\nremove(%s): %s",
      path,
      strerror(ERRNO));
  }
}
#endif /* !NO_FILES */


static void
send_ssi_file(struct mg_connection *, const char *, struct file *, int);


static void
do_ssi_include(struct mg_connection *conn,
  const char *ssi,
  char *tag,
  int include_level)
{
  char file_name[MG_BUF_LEN], path[512], *p;
  struct file file = STRUCT_FILE_INITIALIZER;
  size_t len;
  int truncated = 0;

  if (conn == NULL) {
    return;
  }

  /* sscanf() is safe here, since send_ssi_file() also uses buffer
  * of size MG_BUF_LEN to get the tag. So strlen(tag) is
  * always < MG_BUF_LEN. */
  if (sscanf(tag, " virtual=\"%511[^\"]\"", file_name) == 1) {
    /* File name is relative to the webserver root */
    file_name[511] = 0;
    (void)mg_snprintf(conn,
      &truncated,
      path,
      sizeof(path),
      "%s/%s",
      conn->ctx->config[DOCUMENT_ROOT],
      file_name);

  }
  else if (sscanf(tag, " abspath=\"%511[^\"]\"", file_name) == 1) {
    /* File name is relative to the webserver working directory
    * or it is absolute system path */
    file_name[511] = 0;
    (void)
      mg_snprintf(conn, &truncated, path, sizeof(path), "%s", file_name);

  }
  else if (sscanf(tag, " file=\"%511[^\"]\"", file_name) == 1
    || sscanf(tag, " \"%511[^\"]\"", file_name) == 1) {
    /* File name is relative to the currect document */
    file_name[511] = 0;
    (void)mg_snprintf(conn, &truncated, path, sizeof(path), "%s", ssi);

    if (!truncated) {
      if ((p = strrchr(path, '/')) != NULL) {
        p[1] = '\0';
      }
      len = strlen(path);
      (void)mg_snprintf(conn,
        &truncated,
        path + len,
        sizeof(path) - len,
        "%s",
        file_name);
    }

  }
  else {
    mg_cry(conn, "Bad SSI #include: [%s]", tag);
    return;
  }

  if (truncated) {
    mg_cry(conn, "SSI #include path length overflow: [%s]", tag);
    return;
  }

  if (!mg_fopen(conn, path, "rb", &file)) {
    mg_cry(conn,
      "Cannot open SSI #include: [%s]: fopen(%s): %s",
      tag,
      path,
      strerror(ERRNO));
  }
  else {
    fclose_on_exec(&file, conn);
    if (match_prefix(conn->ctx->config[SSI_EXTENSIONS],
      strlen(conn->ctx->config[SSI_EXTENSIONS]),
      path) > 0) {
      send_ssi_file(conn, path, &file, include_level + 1);
    }
    else {
      send_file_data(conn, &file, 0, INT64_MAX);
    }
    mg_fclose(&file);
  }
}


#if !defined(NO_POPEN)
static void
do_ssi_exec(struct mg_connection *conn, char *tag)
{
  char cmd[1024] = "";
  struct file file = STRUCT_FILE_INITIALIZER;

  if (sscanf(tag, " \"%1023[^\"]\"", cmd) != 1) {
    mg_cry(conn, "Bad SSI #exec: [%s]", tag);
  }
  else {
    cmd[1023] = 0;
    if ((file.fp = popen(cmd, "r")) == NULL) {
      mg_cry(conn, "Cannot SSI #exec: [%s]: %s", cmd, strerror(ERRNO));
    }
    else {
      send_file_data(conn, &file, 0, INT64_MAX);
      pclose(file.fp);
    }
  }
}
#endif /* !NO_POPEN */


static int
mg_fgetc(struct file *filep, int offset)
{
  if (filep == NULL) {
    return EOF;
  }
  if (filep->membuf != NULL && offset >= 0
    && ((unsigned int)(offset)) < filep->size) {
    return ((unsigned char *)filep->membuf)[offset];
  }
  else if (filep->fp != NULL) {
    return fgetc(filep->fp);
  }
  else {
    return EOF;
  }
}


static void
send_ssi_file(struct mg_connection *conn,
  const char *path,
struct file *filep,
  int include_level)
{
  char buf[MG_BUF_LEN];
  int ch, offset, len, in_ssi_tag;

  if (include_level > 10) {
    mg_cry(conn, "SSI #include level is too deep (%s)", path);
    return;
  }

  in_ssi_tag = len = offset = 0;
  while ((ch = mg_fgetc(filep, offset)) != EOF) {
    if (in_ssi_tag && ch == '>') {
      in_ssi_tag = 0;
      buf[len++] = (char)ch;
      buf[len] = '\0';
      /* assert(len <= (int) sizeof(buf)); */
      if (len > (int)sizeof(buf)) {
        break;
      }
      if (len < 6 || memcmp(buf, "<!--#", 5) != 0) {
        /* Not an SSI tag, pass it */
        (void)mg_write(conn, buf, (size_t)len);
      }
      else {
        if (!memcmp(buf + 5, "include", 7)) {
          do_ssi_include(conn, path, buf + 12, include_level);
#if !defined(NO_POPEN)
        }
        else if (!memcmp(buf + 5, "exec", 4)) {
          do_ssi_exec(conn, buf + 9);
#endif /* !NO_POPEN */
        }
        else {
          mg_cry(conn,
            "%s: unknown SSI "
            "command: \"%s\"",
            path,
            buf);
        }
      }
      len = 0;
    }
    else if (in_ssi_tag) {
      if (len == 5 && memcmp(buf, "<!--#", 5) != 0) {
        /* Not an SSI tag */
        in_ssi_tag = 0;
      }
      else if (len == (int)sizeof(buf) - 2) {
        mg_cry(conn, "%s: SSI tag is too large", path);
        len = 0;
      }
      buf[len++] = (char)(ch & 0xff);
    }
    else if (ch == '<') {
      in_ssi_tag = 1;
      if (len > 0) {
        mg_write(conn, buf, (size_t)len);
      }
      len = 0;
      buf[len++] = (char)(ch & 0xff);
    }
    else {
      buf[len++] = (char)(ch & 0xff);
      if (len == (int)sizeof(buf)) {
        mg_write(conn, buf, (size_t)len);
        len = 0;
      }
    }
  }

  /* Send the rest of buffered data */
  if (len > 0) {
    mg_write(conn, buf, (size_t)len);
  }
}


static void
handle_ssi_file_request(struct mg_connection *conn,
  const char *path,
struct file *filep)
{
  char date[64];
  time_t curtime = time(NULL);
  const char *cors1, *cors2, *cors3;

  if (conn == NULL || path == NULL || filep == NULL) {
    return;
  }

  if (mg_get_header(conn, "Origin")) {
    /* Cross-origin resource sharing (CORS). */
    cors1 = "Access-Control-Allow-Origin: ";
    cors2 = conn->ctx->config[ACCESS_CONTROL_ALLOW_ORIGIN];
    cors3 = "\r\n";
  }
  else {
    cors1 = cors2 = cors3 = "";
  }

  if (!mg_fopen(conn, path, "rb", filep)) {
    /* File exists (precondition for calling this function),
    * but can not be opened by the server. */
    send_http_error(conn,
      500,
      "Error: Cannot read file\nfopen(%s): %s",
      path,
      strerror(ERRNO));
  }
  else {
    conn->must_close = 1;
    gmt_time_string(date, sizeof(date), &curtime);
    fclose_on_exec(filep, conn);
    mg_printf(conn, "HTTP/1.1 200 OK\r\n");
    send_no_cache_header(conn);
    mg_printf(conn,
      "%s%s%s"
      "Date: %s\r\n"
      "Content-Type: text/html\r\n"
      "Connection: %s\r\n\r\n",
      cors1,
      cors2,
      cors3,
      date,
      suggest_connection_header(conn));
    send_ssi_file(conn, path, filep, 0);
    mg_fclose(filep);
  }
}


#if !defined(NO_FILES)
static void
send_options(struct mg_connection *conn)
{
  char date[64];
  time_t curtime = time(NULL);

  if (!conn) {
    return;
  }

  conn->status_code = 200;
  conn->must_close = 1;
  gmt_time_string(date, sizeof(date), &curtime);

  mg_printf(conn,
    "HTTP/1.1 200 OK\r\n"
    "Date: %s\r\n"
    /* TODO: "Cache-Control" (?) */
    "Connection: %s\r\n"
    "Allow: GET, POST, HEAD, CONNECT, PUT, DELETE, OPTIONS, "
    "PROPFIND, MKCOL\r\n"
    "DAV: 1\r\n\r\n",
    date,
    suggest_connection_header(conn));
}


/* Writes PROPFIND properties for a collection element */
static void
print_props(struct mg_connection *conn, const char *uri, struct file *filep)
{
  char mtime[64];

  if (conn == NULL || uri == NULL || filep == NULL) {
    return;
  }

  gmt_time_string(mtime, sizeof(mtime), &filep->last_modified);
  conn->num_bytes_sent +=
    mg_printf(conn,
      "<d:response>"
      "<d:href>%s</d:href>"
      "<d:propstat>"
      "<d:prop>"
      "<d:resourcetype>%s</d:resourcetype>"
      "<d:getcontentlength>%" INT64_FMT "</d:getcontentlength>"
      "<d:getlastmodified>%s</d:getlastmodified>"
      "</d:prop>"
      "<d:status>HTTP/1.1 200 OK</d:status>"
      "</d:propstat>"
      "</d:response>\n",
      uri,
      filep->is_directory ? "<d:collection/>" : "",
      filep->size,
      mtime);
}


static void
print_dav_dir_entry(struct de *de, void *data)
{
  char href[PATH_MAX];
  char href_encoded[PATH_MAX];
  int truncated;

  struct mg_connection *conn = (struct mg_connection *)data;
  if (!de || !conn) {
    return;
  }
  mg_snprintf(conn,
    &truncated,
    href,
    sizeof(href),
    "%s%s",
    conn->request_info.local_uri,
    de->file_name);

  if (!truncated) {
    mg_url_encode(href, href_encoded, PATH_MAX - 1);
    print_props(conn, href_encoded, &de->file);
  }
}


static void
handle_propfind(struct mg_connection *conn,
  const char *path,
struct file *filep)
{
  const char *depth = mg_get_header(conn, "Depth");
  char date[64];
  time_t curtime = time(NULL);

  gmt_time_string(date, sizeof(date), &curtime);

  if (!conn || !path || !filep || !conn->ctx) {
    return;
  }

  conn->must_close = 1;
  conn->status_code = 207;
  mg_printf(conn,
    "HTTP/1.1 207 Multi-Status\r\n"
    "Date: %s\r\n",
    date);
  send_static_cache_header(conn);
  mg_printf(conn,
    "Connection: %s\r\n"
    "Content-Type: text/xml; charset=utf-8\r\n\r\n",
    suggest_connection_header(conn));

  conn->num_bytes_sent +=
    mg_printf(conn,
      "<?xml version=\"1.0\" encoding=\"utf-8\"?>"
      "<d:multistatus xmlns:d='DAV:'>\n");

  /* Print properties for the requested resource itself */
  print_props(conn, conn->request_info.local_uri, filep);

  /* If it is a directory, print directory entries too if Depth is not 0 */
  if (filep && filep->is_directory
    && !mg_strcasecmp(conn->ctx->config[ENABLE_DIRECTORY_LISTING], "yes")
    && (depth == NULL || strcmp(depth, "0") != 0)) {
    scan_directory(conn, path, conn, &print_dav_dir_entry);
  }

  conn->num_bytes_sent += mg_printf(conn, "%s\n", "</d:multistatus>");
}
#endif

void
mg_lock_connection(struct mg_connection *conn)
{
  if (conn) {
    (void)pthread_mutex_lock(&conn->mutex);
  }
}

void
mg_unlock_connection(struct mg_connection *conn)
{
  if (conn) {
    (void)pthread_mutex_unlock(&conn->mutex);
  }
}

void
mg_lock_context(struct mg_context *ctx)
{
  if (ctx) {
    (void)pthread_mutex_lock(&ctx->nonce_mutex);
  }
}

void
mg_unlock_context(struct mg_context *ctx)
{
  if (ctx) {
    (void)pthread_mutex_unlock(&ctx->nonce_mutex);
  }
}

#if defined(USE_TIMERS)
#include "timer.inl"
#endif /* USE_TIMERS */

#ifdef USE_LUA
#include "mod_lua.inl"
#endif /* USE_LUA */

#ifdef USE_DUKTAPE
#include "mod_duktape.inl"
#endif /* USE_DUKTAPE */

#if defined(USE_WEBSOCKET)

/* START OF SHA-1 code
* Copyright(c) By Steve Reid <steve@edmweb.com> */
#define SHA1HANDSOFF

/* According to current tests (May 2015), the <solarisfixes.h> is not required.
*
* #if defined(__sun)
* #include "solarisfixes.h"
* #endif
*/


static int
is_big_endian(void)
{
  static const int n = 1;
  return ((char *)&n)[0] == 0;
}


union char64long16 {
  unsigned char c[64];
  uint32_t l[16];
};

#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))


static uint32_t
blk0(union char64long16 *block, int i)
{
  /* Forrest: SHA expect BIG_ENDIAN, swap if LITTLE_ENDIAN */
  if (!is_big_endian()) {
    block->l[i] = (rol(block->l[i], 24) & 0xFF00FF00)
      | (rol(block->l[i], 8) & 0x00FF00FF);
  }
  return block->l[i];
}

#define blk(i)                                                                 \
	(block->l[i & 15] = rol(block->l[(i + 13) & 15] ^ block->l[(i + 8) & 15]   \
	                            ^ block->l[(i + 2) & 15] ^ block->l[i & 15],   \
	                        1))
#define R0(v, w, x, y, z, i)                                                   \
	z += ((w & (x ^ y)) ^ y) + blk0(block, i) + 0x5A827999 + rol(v, 5);        \
	w = rol(w, 30);
#define R1(v, w, x, y, z, i)                                                   \
	z += ((w & (x ^ y)) ^ y) + blk(i) + 0x5A827999 + rol(v, 5);                \
	w = rol(w, 30);
#define R2(v, w, x, y, z, i)                                                   \
	z += (w ^ x ^ y) + blk(i) + 0x6ED9EBA1 + rol(v, 5);                        \
	w = rol(w, 30);
#define R3(v, w, x, y, z, i)                                                   \
	z += (((w | x) & y) | (w & x)) + blk(i) + 0x8F1BBCDC + rol(v, 5);          \
	w = rol(w, 30);
#define R4(v, w, x, y, z, i)                                                   \
	z += (w ^ x ^ y) + blk(i) + 0xCA62C1D6 + rol(v, 5);                        \
	w = rol(w, 30);


typedef struct {
  uint32_t state[5];
  uint32_t count[2];
  unsigned char buffer[64];
} SHA1_CTX;


static void
SHA1Transform(uint32_t state[5], const unsigned char buffer[64])
{
  uint32_t a, b, c, d, e;
  union char64long16 block[1];

  memcpy(block, buffer, 64);
  a = state[0];
  b = state[1];
  c = state[2];
  d = state[3];
  e = state[4];
  R0(a, b, c, d, e, 0);
  R0(e, a, b, c, d, 1);
  R0(d, e, a, b, c, 2);
  R0(c, d, e, a, b, 3);
  R0(b, c, d, e, a, 4);
  R0(a, b, c, d, e, 5);
  R0(e, a, b, c, d, 6);
  R0(d, e, a, b, c, 7);
  R0(c, d, e, a, b, 8);
  R0(b, c, d, e, a, 9);
  R0(a, b, c, d, e, 10);
  R0(e, a, b, c, d, 11);
  R0(d, e, a, b, c, 12);
  R0(c, d, e, a, b, 13);
  R0(b, c, d, e, a, 14);
  R0(a, b, c, d, e, 15);
  R1(e, a, b, c, d, 16);
  R1(d, e, a, b, c, 17);
  R1(c, d, e, a, b, 18);
  R1(b, c, d, e, a, 19);
  R2(a, b, c, d, e, 20);
  R2(e, a, b, c, d, 21);
  R2(d, e, a, b, c, 22);
  R2(c, d, e, a, b, 23);
  R2(b, c, d, e, a, 24);
  R2(a, b, c, d, e, 25);
  R2(e, a, b, c, d, 26);
  R2(d, e, a, b, c, 27);
  R2(c, d, e, a, b, 28);
  R2(b, c, d, e, a, 29);
  R2(a, b, c, d, e, 30);
  R2(e, a, b, c, d, 31);
  R2(d, e, a, b, c, 32);
  R2(c, d, e, a, b, 33);
  R2(b, c, d, e, a, 34);
  R2(a, b, c, d, e, 35);
  R2(e, a, b, c, d, 36);
  R2(d, e, a, b, c, 37);
  R2(c, d, e, a, b, 38);
  R2(b, c, d, e, a, 39);
  R3(a, b, c, d, e, 40);
  R3(e, a, b, c, d, 41);
  R3(d, e, a, b, c, 42);
  R3(c, d, e, a, b, 43);
  R3(b, c, d, e, a, 44);
  R3(a, b, c, d, e, 45);
  R3(e, a, b, c, d, 46);
  R3(d, e, a, b, c, 47);
  R3(c, d, e, a, b, 48);
  R3(b, c, d, e, a, 49);
  R3(a, b, c, d, e, 50);
  R3(e, a, b, c, d, 51);
  R3(d, e, a, b, c, 52);
  R3(c, d, e, a, b, 53);
  R3(b, c, d, e, a, 54);
  R3(a, b, c, d, e, 55);
  R3(e, a, b, c, d, 56);
  R3(d, e, a, b, c, 57);
  R3(c, d, e, a, b, 58);
  R3(b, c, d, e, a, 59);
  R4(a, b, c, d, e, 60);
  R4(e, a, b, c, d, 61);
  R4(d, e, a, b, c, 62);
  R4(c, d, e, a, b, 63);
  R4(b, c, d, e, a, 64);
  R4(a, b, c, d, e, 65);
  R4(e, a, b, c, d, 66);
  R4(d, e, a, b, c, 67);
  R4(c, d, e, a, b, 68);
  R4(b, c, d, e, a, 69);
  R4(a, b, c, d, e, 70);
  R4(e, a, b, c, d, 71);
  R4(d, e, a, b, c, 72);
  R4(c, d, e, a, b, 73);
  R4(b, c, d, e, a, 74);
  R4(a, b, c, d, e, 75);
  R4(e, a, b, c, d, 76);
  R4(d, e, a, b, c, 77);
  R4(c, d, e, a, b, 78);
  R4(b, c, d, e, a, 79);
  state[0] += a;
  state[1] += b;
  state[2] += c;
  state[3] += d;
  state[4] += e;
  a = b = c = d = e = 0;
  memset(block, '\0', sizeof(block));
}


static void
SHA1Init(SHA1_CTX *context)
{
  context->state[0] = 0x67452301;
  context->state[1] = 0xEFCDAB89;
  context->state[2] = 0x98BADCFE;
  context->state[3] = 0x10325476;
  context->state[4] = 0xC3D2E1F0;
  context->count[0] = context->count[1] = 0;
}


static void
SHA1Update(SHA1_CTX *context, const unsigned char *data, uint32_t len)
{
  uint32_t i, j;

  j = context->count[0];
  if ((context->count[0] += len << 3) < j) {
    context->count[1]++;
  }
  context->count[1] += (len >> 29);
  j = (j >> 3) & 63;
  if ((j + len) > 63) {
    memcpy(&context->buffer[j], data, (i = 64 - j));
    SHA1Transform(context->state, context->buffer);
    for (; i + 63 < len; i += 64) {
      SHA1Transform(context->state, &data[i]);
    }
    j = 0;
  }
  else
    i = 0;
  memcpy(&context->buffer[j], &data[i], len - i);
}


static void
SHA1Final(unsigned char digest[20], SHA1_CTX *context)
{
  unsigned i;
  unsigned char finalcount[8], c;

  for (i = 0; i < 8; i++) {
    finalcount[i] = (unsigned char)((context->count[(i >= 4 ? 0 : 1)]
      >> ((3 - (i & 3)) * 8)) & 255);
  }
  c = 0200;
  SHA1Update(context, &c, 1);
  while ((context->count[0] & 504) != 448) {
    c = 0000;
    SHA1Update(context, &c, 1);
  }
  SHA1Update(context, finalcount, 8);
  for (i = 0; i < 20; i++) {
    digest[i] = (unsigned char)((context->state[i >> 2]
      >> ((3 - (i & 3)) * 8)) & 255);
  }
  memset(context, '\0', sizeof(*context));
  memset(&finalcount, '\0', sizeof(finalcount));
}
/* END OF SHA1 CODE */


static int
send_websocket_handshake(struct mg_connection *conn, const char *websock_key)
{
  static const char *magic = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
  const char *protocol = NULL;
  char buf[100], sha[20], b64_sha[sizeof(sha) * 2];
  SHA1_CTX sha_ctx;
  int truncated;

  /* Calculate Sec-WebSocket-Accept reply from Sec-WebSocket-Key. */
  mg_snprintf(conn, &truncated, buf, sizeof(buf), "%s%s", websock_key, magic);
  if (truncated) {
    conn->must_close = 1;
    return 0;
  }

  SHA1Init(&sha_ctx);
  SHA1Update(&sha_ctx, (unsigned char *)buf, (uint32_t)strlen(buf));
  SHA1Final((unsigned char *)sha, &sha_ctx);
  base64_encode((unsigned char *)sha, sizeof(sha), b64_sha);
  mg_printf(conn,
    "HTTP/1.1 101 Switching Protocols\r\n"
    "Upgrade: websocket\r\n"
    "Connection: Upgrade\r\n"
    "Sec-WebSocket-Accept: %s\r\n",
    b64_sha);
  protocol = mg_get_header(conn, "Sec-WebSocket-Protocol");
  if (protocol) {
    mg_printf(conn, "Sec-WebSocket-Protocol: %s\r\n\r\n", protocol);
  }
  else {
    mg_printf(conn, "%s", "\r\n");
  }

  return 1;
}


static void
read_websocket(struct mg_connection *conn,
  mg_websocket_data_handler ws_data_handler,
  void *callback_data)
{
  /* Pointer to the beginning of the portion of the incoming websocket
  * message queue.
  * The original websocket upgrade request is never removed, so the queue
  * begins after it. */
  unsigned char *buf = (unsigned char *)conn->buf + conn->request_len;
  int n, error, exit_by_callback;

  /* body_len is the length of the entire queue in bytes
  * len is the length of the current message
  * data_len is the length of the current message's data payload
  * header_len is the length of the current message's header */
  size_t i, len, mask_len = 0, data_len = 0, header_len, body_len;

  /* "The masking key is a 32-bit value chosen at random by the client."
  * http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-17#section-5
  */
  unsigned char mask[4];

  /* data points to the place where the message is stored when passed to the
  * websocket_data callback.  This is either mem on the stack, or a
  * dynamically allocated buffer if it is too large. */
  char mem[4096];
  char *data = mem;
  unsigned char mop; /* mask flag and opcode */
  double timeout = -1.0;

  if (conn->ctx->config[WEBSOCKET_TIMEOUT]) {
    timeout = atoi(conn->ctx->config[WEBSOCKET_TIMEOUT]) / 1000.0;
  }
  if ((timeout <= 0.0) && (conn->ctx->config[REQUEST_TIMEOUT])) {
    timeout = atoi(conn->ctx->config[REQUEST_TIMEOUT]) / 1000.0;
  }

  mg_set_thread_name("wsock");

  /* Loop continuously, reading messages from the socket, invoking the
  * callback, and waiting repeatedly until an error occurs. */
  while (!conn->ctx->stop_flag) {
    header_len = 0;
    assert(conn->data_len >= conn->request_len);
    if ((body_len = (size_t)(conn->data_len - conn->request_len)) >= 2) {
      len = buf[1] & 127;
      mask_len = buf[1] & 128 ? 4 : 0;
      if (len < 126 && body_len >= mask_len) {
        data_len = len;
        header_len = 2 + mask_len;
      }
      else if (len == 126 && body_len >= 4 + mask_len) {
        header_len = 4 + mask_len;
        data_len = ((((size_t)buf[2]) << 8) + buf[3]);
      }
      else if (body_len >= 10 + mask_len) {
        header_len = 10 + mask_len;
        data_len = (((uint64_t)ntohl(*(uint32_t *)(void *)&buf[2]))
          << 32) + ntohl(*(uint32_t *)(void *)&buf[6]);
      }
    }

    if (header_len > 0 && body_len >= header_len) {
      /* Allocate space to hold websocket payload */
      data = mem;
      if (data_len > sizeof(mem)) {
        data = (char *)mg_malloc(data_len);
        if (data == NULL) {
          /* Allocation failed, exit the loop and then close the
          * connection */
          mg_cry(conn, "websocket out of memory; closing connection");
          break;
        }
      }

      /* Copy the mask before we shift the queue and destroy it */
      if (mask_len > 0) {
        memcpy(mask, buf + header_len - mask_len, sizeof(mask));
      }
      else {
        memset(mask, 0, sizeof(mask));
      }

      /* Read frame payload from the first message in the queue into
      * data and advance the queue by moving the memory in place. */
      assert(body_len >= header_len);
      if (data_len + header_len > body_len) {
        mop = buf[0]; /* current mask and opcode */
                      /* Overflow case */
        len = body_len - header_len;
        memcpy(data, buf + header_len, len);
        error = 0;
        while (len < data_len) {
          n = pull(
            NULL, conn, data + len, (int)(data_len - len), timeout);
          if (n <= 0) {
            error = 1;
            break;
          }
          len += (size_t)n;
        }
        if (error) {
          mg_cry(conn, "Websocket pull failed; closing connection");
          break;
        }
        conn->data_len = conn->request_len;
      }
      else {
        mop = buf[0]; /* current mask and opcode, overwritten by
                      * memmove() */
                      /* Length of the message being read at the front of the
                      * queue */
        len = data_len + header_len;

        /* Copy the data payload into the data pointer for the
        * callback */
        memcpy(data, buf + header_len, data_len);

        /* Move the queue forward len bytes */
        memmove(buf, buf + len, body_len - len);

        /* Mark the queue as advanced */
        conn->data_len -= (int)len;
      }

      /* Apply mask if necessary */
      if (mask_len > 0) {
        for (i = 0; i < data_len; ++i) {
          data[i] ^= mask[i & 3];
        }
      }

      /* Exit the loop if callback signals to exit (server side),
      * or "connection close" opcode received (client side). */
      exit_by_callback = 0;
      if ((ws_data_handler != NULL)
        && !ws_data_handler(conn, mop, data, data_len, callback_data)) {
        exit_by_callback = 1;
      }

      if (data != mem) {
        mg_free(data);
      }

      if (exit_by_callback
        || ((mop & 0xf) == WEBSOCKET_OPCODE_CONNECTION_CLOSE)) {
        /* Opcode == 8, connection close */
        break;
      }

      /* Not breaking the loop, process next websocket frame. */
    }
    else {
      /* Read from the socket into the next available location in the
      * message queue. */
      if ((n = pull(NULL,
        conn,
        conn->buf + conn->data_len,
        conn->buf_size - conn->data_len,
        timeout)) <= 0) {
        /* Error, no bytes read */
        break;
      }
      conn->data_len += n;
    }
  }

  mg_set_thread_name("worker");
}


static int
mg_websocket_write_exec(struct mg_connection *conn,
  int opcode,
  const char *data,
  size_t dataLen,
  uint32_t masking_key)
{
  unsigned char header[14];
  size_t headerLen = 1;

  int retval = -1;

  header[0] = 0x80 + (opcode & 0xF);

  /* Frame format: http://tools.ietf.org/html/rfc6455#section-5.2 */
  if (dataLen < 126) {
    /* inline 7-bit length field */
    header[1] = (unsigned char)dataLen;
    headerLen = 2;
  }
  else if (dataLen <= 0xFFFF) {
    /* 16-bit length field */
    header[1] = 126;
    *(uint16_t *)(void *)(header + 2) = htons((uint16_t)dataLen);
    headerLen = 4;
  }
  else {
    /* 64-bit length field */
    header[1] = 127;
    *(uint32_t *)(void *)(header + 2) = htonl((uint64_t)dataLen >> 32);
    *(uint32_t *)(void *)(header + 6) = htonl(dataLen & 0xFFFFFFFF);
    headerLen = 10;
  }

  if (masking_key) {
    /* add mask */
    header[1] |= 0x80;
    *(uint32_t *)(void *)(header + headerLen) = masking_key;
    headerLen += 4;
  }


  /* Note that POSIX/Winsock's send() is threadsafe
  * http://stackoverflow.com/questions/1981372/are-parallel-calls-to-send-recv-on-the-same-socket-valid
  * but mongoose's mg_printf/mg_write is not (because of the loop in
  * push(), although that is only a problem if the packet is large or
  * outgoing buffer is full). */
  (void)mg_lock_connection(conn);
  retval = mg_write(conn, header, headerLen);
  if (dataLen > 0) {
    retval = mg_write(conn, data, dataLen);
  }
  mg_unlock_connection(conn);

  return retval;
}

int
mg_websocket_write(struct mg_connection *conn,
  int opcode,
  const char *data,
  size_t dataLen)
{
  return mg_websocket_write_exec(conn, opcode, data, dataLen, 0);
}


static void
mask_data(const char *in, size_t in_len, uint32_t masking_key, char *out)
{
  size_t i = 0;

  i = 0;
  if ((in_len > 3) && ((ptrdiff_t)in % 4) == 0) {
    /* Convert in 32 bit words, if data is 4 byte aligned */
    while (i < (in_len - 3)) {
      *(uint32_t *)(void *)(out + i) =
        *(uint32_t *)(void *)(in + i) ^ masking_key;
      i += 4;
    }
  }
  if (i != in_len) {
    /* convert 1-3 remaining bytes if ((dataLen % 4) != 0)*/
    while (i < in_len) {
      *(uint8_t *)(void *)(out + i) =
        *(uint8_t *)(void *)(in + i)
        ^ *(((uint8_t *)&masking_key) + (i % 4));
      i++;
    }
  }
}


int
mg_websocket_client_write(struct mg_connection *conn,
  int opcode,
  const char *data,
  size_t dataLen)
{
  int retval = -1;
  char *masked_data = (char *)mg_malloc(((dataLen + 7) / 4) * 4);
  uint32_t masking_key = (uint32_t)get_random();

  if (masked_data == NULL) {
    /* Return -1 in an error case */
    mg_cry(conn,
      "Cannot allocate buffer for masked websocket response: "
      "Out of memory");
    return -1;
  }

  mask_data(data, dataLen, masking_key, masked_data);

  retval = mg_websocket_write_exec(
    conn, opcode, masked_data, dataLen, masking_key);
  mg_free(masked_data);

  return retval;
}


static void
handle_websocket_request(struct mg_connection *conn,
  const char *path,
  int is_callback_resource,
  mg_websocket_connect_handler ws_connect_handler,
  mg_websocket_ready_handler ws_ready_handler,
  mg_websocket_data_handler ws_data_handler,
  mg_websocket_close_handler ws_close_handler,
  void *cbData)
{
  const char *websock_key = mg_get_header(conn, "Sec-WebSocket-Key");
  const char *version = mg_get_header(conn, "Sec-WebSocket-Version");
  int lua_websock = 0;

#if !defined(USE_LUA)
  (void)path;
#endif

  /* Step 1: Check websocket protocol version. */
  /* Step 1.1: Check Sec-WebSocket-Key. */
  if (!websock_key) {
    /* The RFC standard version (https://tools.ietf.org/html/rfc6455)
    * requires a Sec-WebSocket-Key header.
    */
    /* It could be the hixie draft version
    * (http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol-76).
    */
    const char *key1 = mg_get_header(conn, "Sec-WebSocket-Key1");
    const char *key2 = mg_get_header(conn, "Sec-WebSocket-Key2");
    char key3[8];

    if ((key1 != NULL) && (key2 != NULL)) {
      /* This version uses 8 byte body data in a GET request */
      conn->content_len = 8;
      if (8 == mg_read(conn, key3, 8)) {
        /* This is the hixie version */
        send_http_error(conn,
          426,
          "%s",
          "Protocol upgrade to RFC 6455 required");
        return;
      }
    }
    /* This is an unknown version */
    send_http_error(conn, 400, "%s", "Malformed websocket request");
    return;
  }

  /* Step 1.2: Check websocket protocol version. */
  /* The RFC version (https://tools.ietf.org/html/rfc6455) is 13. */
  if (version == NULL || strcmp(version, "13") != 0) {
    /* Reject wrong versions */
    send_http_error(conn, 426, "%s", "Protocol upgrade required");
    return;
  }

  /* Step 1.3: Could check for "Host", but we do not really nead this
  * value for anything, so just ignore it. */

  /* Step 2: If a callback is responsible, call it. */
  if (is_callback_resource) {
    if (ws_connect_handler != NULL
      && ws_connect_handler(conn, cbData) != 0) {
      /* C callback has returned non-zero, do not proceed with
      * handshake.
      */
      /* Note that C callbacks are no longer called when Lua is
      * responsible, so C can no longer filter callbacks for Lua. */
      return;
    }
  }
#if defined(USE_LUA)
  /* Step 3: No callback. Check if Lua is responsible. */
  else {
    /* Step 3.1: Check if Lua is responsible. */
    if (conn->ctx->config[LUA_WEBSOCKET_EXTENSIONS]) {
      lua_websock =
        match_prefix(conn->ctx->config[LUA_WEBSOCKET_EXTENSIONS],
          strlen(
            conn->ctx->config[LUA_WEBSOCKET_EXTENSIONS]),
          path);
    }

    if (lua_websock) {
      /* Step 3.2: Lua is responsible: call it. */
      conn->lua_websocket_state = lua_websocket_new(path, conn);
      if (!conn->lua_websocket_state) {
        /* Lua rejected the new client */
        return;
      }
    }
  }
#endif

  /* Step 4: Check if there is a responsible websocket handler. */
  if (!is_callback_resource && !lua_websock) {
    /* There is no callback, an Lua is not responsible either. */
    /* Reply with a 404 Not Found or with nothing at all?
    * TODO (mid): check the websocket standards, how to reply to
    * requests to invalid websocket addresses. */
    send_http_error(conn, 404, "%s", "Not found");
    return;
  }

  /* Step 5: The websocket connection has been accepted */
  if (!send_websocket_handshake(conn, websock_key)) {
    send_http_error(conn, 500, "%s", "Websocket handshake failed");
    return;
  }

  /* Step 6: Call the ready handler */
  if (is_callback_resource) {
    if (ws_ready_handler != NULL) {
      ws_ready_handler(conn, cbData);
    }
#if defined(USE_LUA)
  }
  else if (lua_websock) {
    if (!lua_websocket_ready(conn, conn->lua_websocket_state)) {
      /* the ready handler returned false */
      return;
    }
#endif
  }

  /* Step 7: Enter the read loop */
  if (is_callback_resource) {
    read_websocket(conn, ws_data_handler, cbData);
#if defined(USE_LUA)
  }
  else if (lua_websock) {
    read_websocket(conn, lua_websocket_data, conn->lua_websocket_state);
#endif
  }

  /* Step 8: Call the close handler */
  if (ws_close_handler) {
    ws_close_handler(conn, cbData);
  }
}


static int
is_websocket_protocol(const struct mg_connection *conn)
{
  const char *upgrade, *connection;

  /* A websocket protocoll has the following HTTP headers:
  *
  * Connection: Upgrade
  * Upgrade: Websocket
  */

  upgrade = mg_get_header(conn, "Upgrade");
  if (upgrade == NULL) {
    return 0; /* fail early, don't waste time checking other header
              * fields
              */
  }
  if (!mg_strcasestr(upgrade, "websocket")) {
    return 0;
  }

  connection = mg_get_header(conn, "Connection");
  if (connection == NULL) {
    return 0;
  }
  if (!mg_strcasestr(connection, "upgrade")) {
    return 0;
  }

  /* The headers "Host", "Sec-WebSocket-Key", "Sec-WebSocket-Protocol" and
  * "Sec-WebSocket-Version" are also required.
  * Don't check them here, since even an unsupported websocket protocol
  * request still IS a websocket request (in contrast to a standard HTTP
  * request). It will fail later in handle_websocket_request.
  */

  return 1;
}
#endif /* !USE_WEBSOCKET */


static int
isbyte(int n)
{
  return n >= 0 && n <= 255;
}


static int
parse_net(const char *spec, uint32_t *net, uint32_t *mask)
{
  int n, a, b, c, d, slash = 32, len = 0;

  if ((sscanf(spec, "%d.%d.%d.%d/%d%n", &a, &b, &c, &d, &slash, &n) == 5
    || sscanf(spec, "%d.%d.%d.%d%n", &a, &b, &c, &d, &n) == 4) && isbyte(a)
    && isbyte(b) && isbyte(c) && isbyte(d) && slash >= 0
    && slash < 33) {
    len = n;
    *net = ((uint32_t)a << 24) | ((uint32_t)b << 16) | ((uint32_t)c << 8)
      | (uint32_t)d;
    *mask = slash ? 0xffffffffU << (32 - slash) : 0;
  }

  return len;
}


static int
set_throttle(const char *spec, uint32_t remote_ip, const char *uri)
{
  int throttle = 0;
  struct vec vec, val;
  uint32_t net, mask;
  char mult;
  double v;

  while ((spec = next_option(spec, &vec, &val)) != NULL) {
    mult = ',';
    if (sscanf(val.ptr, "%lf%c", &v, &mult) < 1 || v < 0
      || (lowercase(&mult) != 'k' && lowercase(&mult) != 'm'
        && mult != ',')) {
      continue;
    }
    v *= lowercase(&mult) == 'k' ? 1024 : lowercase(&mult) == 'm' ? 1048576
      : 1;
    if (vec.len == 1 && vec.ptr[0] == '*') {
      throttle = (int)v;
    }
    else if (parse_net(vec.ptr, &net, &mask) > 0) {
      if ((remote_ip & mask) == net) {
        throttle = (int)v;
      }
    }
    else if (match_prefix(vec.ptr, vec.len, uri) > 0) {
      throttle = (int)v;
    }
  }

  return throttle;
}


static uint32_t
get_remote_ip(const struct mg_connection *conn)
{
  if (!conn) {
    return 0;
  }
  return ntohl(*(uint32_t *)&conn->client.rsa.sin.sin_addr);
}


/* Experimental replacement for mg_upload. */
#include "handle_form.inl"


/* Replacement for mg_upload (Note: mg_upload is deprecated) */
struct mg_upload_user_data {
  struct mg_connection *conn;
  const char *destination_dir;
  int num_uploaded_files;
};


/* Helper function for deprecated mg_upload. */
static int
mg_upload_field_found(const char *key,
  const char *filename,
  char *path,
  size_t pathlen,
  void *user_data)
{
  int truncated = 0;
  struct mg_upload_user_data *fud = (struct mg_upload_user_data *)user_data;
  (void)key;

  if (!filename) {
    mg_cry(fud->conn, "%s: No filename set", __func__);
    return FORM_FIELD_STORAGE_ABORT;
  }
  mg_snprintf(fud->conn,
    &truncated,
    path,
    pathlen - 1,
    "%s/%s",
    fud->destination_dir,
    filename);
  if (!truncated) {
    mg_cry(fud->conn, "%s: File path too long", __func__);
    return FORM_FIELD_STORAGE_ABORT;
  }
  return FORM_FIELD_STORAGE_STORE;
}


/* Helper function for deprecated mg_upload. */
static int
mg_upload_field_get(const char *key,
  const char *value,
  size_t value_size,
  void *user_data)
{
  /* Function should never be called */
  (void)key;
  (void)value;
  (void)value_size;
  (void)user_data;

  return 0;
}


/* Helper function for deprecated mg_upload. */
static int
mg_upload_field_stored(const char *path, size_t file_size, void *user_data)
{
  struct mg_upload_user_data *fud = (struct mg_upload_user_data *)user_data;
  (void)file_size;

  fud->num_uploaded_files++;
  fud->conn->ctx->callbacks.upload(fud->conn, path);

  return 0;
}


/* Deprecated function mg_upload - use mg_handle_form_request instead. */
int
mg_upload(struct mg_connection *conn, const char *destination_dir)
{
  struct mg_upload_user_data fud = { conn, destination_dir, 0 };
  struct mg_form_data_handler fdh = { mg_upload_field_found,
    mg_upload_field_get,
    mg_upload_field_stored,
    0 };
  int ret;

  fdh.user_data = (void *)&fud;
  ret = mg_handle_form_request(conn, &fdh);

  if (ret < 0) {
    mg_cry(conn, "%s: Error while parsing the request", __func__);
  }

  return fud.num_uploaded_files;
}


static int
get_first_ssl_listener_index(const struct mg_context *ctx)
{
  unsigned int i;
  int idx = -1;
  if (ctx) {
    for (i = 0; idx == -1 && i < ctx->num_listening_sockets; i++) {
      idx = ctx->listening_sockets[i].is_ssl ? ((int)(i)) : -1;
    }
  }
  return idx;
}


static void
redirect_to_https_port(struct mg_connection *conn, int ssl_index)
{
  char host[1025];
  const char *host_header;
  size_t hostlen;

  host_header = mg_get_header(conn, "Host");
  hostlen = sizeof(host);
  if (host_header != NULL) {
    char *pos;

    mg_strlcpy(host, host_header, hostlen);
    host[hostlen - 1] = '\0';
    pos = strchr(host, ':');
    if (pos != NULL) {
      *pos = '\0';
    }
  }
  else {
    /* Cannot get host from the Host: header.
    * Fallback to our IP address. */
    if (conn) {
      sockaddr_to_string(host, hostlen, &conn->client.lsa);
    }
  }

  /* Send host, port, uri and (if it exists) ?query_string */
  if (conn) {
    mg_printf(conn,
      "HTTP/1.1 302 Found\r\nLocation: https://%s:%d%s%s%s\r\n\r\n",
      host,
      (int)ntohs(
        conn->ctx->listening_sockets[ssl_index].lsa.sin.sin_port),
      conn->request_info.local_uri,
      (conn->request_info.query_string == NULL) ? "" : "?",
      (conn->request_info.query_string == NULL)
      ? ""
      : conn->request_info.query_string);
  }
}


static void
mg_set_handler_type(struct mg_context *ctx,
  const char *uri,
  int handler_type,
  int is_delete_request,
  mg_request_handler handler,
  mg_websocket_connect_handler connect_handler,
  mg_websocket_ready_handler ready_handler,
  mg_websocket_data_handler data_handler,
  mg_websocket_close_handler close_handler,
  mg_authorization_handler auth_handler,
  void *cbdata)
{
  struct mg_handler_info *tmp_rh, **lastref;
  size_t urilen = strlen(uri);

  if (handler_type == WEBSOCKET_HANDLER) {
    /* assert(handler == NULL); */
    /* assert(is_delete_request || connect_handler!=NULL ||
    *        ready_handler!=NULL || data_handler!=NULL ||
    *        close_handler!=NULL);
    */
    /* assert(auth_handler == NULL); */
    if (handler != NULL) {
      return;
    }
    if (!is_delete_request && connect_handler == NULL
      && ready_handler == NULL
      && data_handler == NULL
      && close_handler == NULL) {
      return;
    }
    if (auth_handler != NULL) {
      return;
    }
  }
  else if (handler_type == REQUEST_HANDLER) {
    /* assert(connect_handler==NULL && ready_handler==NULL &&
    *        data_handler==NULL && close_handler==NULL); */
    /* assert(is_delete_request || (handler!=NULL));
    */
    /* assert(auth_handler == NULL); */
    if (connect_handler != NULL || ready_handler != NULL
      || data_handler != NULL
      || close_handler != NULL) {
      return;
    }
    if (!is_delete_request && (handler == NULL)) {
      return;
    }
    if (auth_handler != NULL) {
      return;
    }
  }
  else { /* AUTH_HANDLER */
         /* assert(handler == NULL); */
         /* assert(connect_handler==NULL && ready_handler==NULL &&
         *        data_handler==NULL && close_handler==NULL); */
         /* assert(auth_handler != NULL); */
    if (handler != NULL) {
      return;
    }
    if (connect_handler != NULL || ready_handler != NULL
      || data_handler != NULL
      || close_handler != NULL) {
      return;
    }
    if (!is_delete_request && (auth_handler == NULL)) {
      return;
    }
  }

  if (!ctx) {
    return;
  }

  mg_lock_context(ctx);

  /* first try to find an existing handler */
  lastref = &(ctx->handlers);
  for (tmp_rh = ctx->handlers; tmp_rh != NULL; tmp_rh = tmp_rh->next) {
    if (tmp_rh->handler_type == handler_type) {
      if (urilen == tmp_rh->uri_len && !strcmp(tmp_rh->uri, uri)) {
        if (!is_delete_request) {
          /* update existing handler */
          if (handler_type == REQUEST_HANDLER) {
            tmp_rh->handler = handler;
          }
          else if (handler_type == WEBSOCKET_HANDLER) {
            tmp_rh->connect_handler = connect_handler;
            tmp_rh->ready_handler = ready_handler;
            tmp_rh->data_handler = data_handler;
            tmp_rh->close_handler = close_handler;
          }
          else { /* AUTH_HANDLER */
            tmp_rh->auth_handler = auth_handler;
          }
          tmp_rh->cbdata = cbdata;
        }
        else {
          /* remove existing handler */
          *lastref = tmp_rh->next;
          mg_free(tmp_rh->uri);
          mg_free(tmp_rh);
        }
        mg_unlock_context(ctx);
        return;
      }
    }
    lastref = &(tmp_rh->next);
  }

  if (is_delete_request) {
    /* no handler to set, this was a remove request to a non-existing
    * handler */
    mg_unlock_context(ctx);
    return;
  }

  tmp_rh =
    (struct mg_handler_info *)mg_calloc(sizeof(struct mg_handler_info), 1);
  if (tmp_rh == NULL) {
    mg_unlock_context(ctx);
    mg_cry(fc(ctx), "%s", "Cannot create new request handler struct, OOM");
    return;
  }
  tmp_rh->uri = mg_strdup(uri);
  if (!tmp_rh->uri) {
    mg_unlock_context(ctx);
    mg_free(tmp_rh);
    mg_cry(fc(ctx), "%s", "Cannot create new request handler struct, OOM");
    return;
  }
  tmp_rh->uri_len = urilen;
  if (handler_type == REQUEST_HANDLER) {
    tmp_rh->handler = handler;
  }
  else if (handler_type == WEBSOCKET_HANDLER) {
    tmp_rh->connect_handler = connect_handler;
    tmp_rh->ready_handler = ready_handler;
    tmp_rh->data_handler = data_handler;
    tmp_rh->close_handler = close_handler;
  }
  else { /* AUTH_HANDLER */
    tmp_rh->auth_handler = auth_handler;
  }
  tmp_rh->cbdata = cbdata;
  tmp_rh->handler_type = handler_type;
  tmp_rh->next = NULL;

  *lastref = tmp_rh;
  mg_unlock_context(ctx);
}


void
mg_set_request_handler(struct mg_context *ctx,
  const char *uri,
  mg_request_handler handler,
  void *cbdata)
{
  mg_set_handler_type(ctx,
    uri,
    REQUEST_HANDLER,
    handler == NULL,
    handler,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    cbdata);
}


void
mg_set_websocket_handler(struct mg_context *ctx,
  const char *uri,
  mg_websocket_connect_handler connect_handler,
  mg_websocket_ready_handler ready_handler,
  mg_websocket_data_handler data_handler,
  mg_websocket_close_handler close_handler,
  void *cbdata)
{
  int is_delete_request = (connect_handler == NULL) && (ready_handler == NULL)
    && (data_handler == NULL)
    && (close_handler == NULL);
  mg_set_handler_type(ctx,
    uri,
    WEBSOCKET_HANDLER,
    is_delete_request,
    NULL,
    connect_handler,
    ready_handler,
    data_handler,
    close_handler,
    NULL,
    cbdata);
}

void
mg_set_auth_handler(struct mg_context *ctx,
  const char *uri,
  mg_request_handler handler,
  void *cbdata)
{
  mg_set_handler_type(ctx,
    uri,
    AUTH_HANDLER,
    handler == NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    handler,
    cbdata);
}

static int
get_request_handler(struct mg_connection *conn,
  int handler_type,
  mg_request_handler *handler,
  mg_websocket_connect_handler *connect_handler,
  mg_websocket_ready_handler *ready_handler,
  mg_websocket_data_handler *data_handler,
  mg_websocket_close_handler *close_handler,
  mg_authorization_handler *auth_handler,
  void **cbdata)
{
  const struct mg_request_info *request_info = mg_get_request_info(conn);
  if (request_info) {
    const char *uri = request_info->local_uri;
    size_t urilen = strlen(uri);
    struct mg_handler_info *tmp_rh;

    if (!conn || !conn->ctx) {
      return 0;
    }

    mg_lock_context(conn->ctx);

    /* first try for an exact match */
    for (tmp_rh = conn->ctx->handlers; tmp_rh != NULL;
    tmp_rh = tmp_rh->next) {
      if (tmp_rh->handler_type == handler_type) {
        if (urilen == tmp_rh->uri_len && !strcmp(tmp_rh->uri, uri)) {
          if (handler_type == WEBSOCKET_HANDLER) {
            *connect_handler = tmp_rh->connect_handler;
            *ready_handler = tmp_rh->ready_handler;
            *data_handler = tmp_rh->data_handler;
            *close_handler = tmp_rh->close_handler;
          }
          else if (handler_type == REQUEST_HANDLER) {
            *handler = tmp_rh->handler;
          }
          else { /* AUTH_HANDLER */
            *auth_handler = tmp_rh->auth_handler;
          }
          *cbdata = tmp_rh->cbdata;
          mg_unlock_context(conn->ctx);
          return 1;
        }
      }
    }

    /* next try for a partial match, we will accept uri/something */
    for (tmp_rh = conn->ctx->handlers; tmp_rh != NULL;
    tmp_rh = tmp_rh->next) {
      if (tmp_rh->handler_type == handler_type) {
        if (tmp_rh->uri_len < urilen && uri[tmp_rh->uri_len] == '/'
          && memcmp(tmp_rh->uri, uri, tmp_rh->uri_len) == 0) {
          if (handler_type == WEBSOCKET_HANDLER) {
            *connect_handler = tmp_rh->connect_handler;
            *ready_handler = tmp_rh->ready_handler;
            *data_handler = tmp_rh->data_handler;
            *close_handler = tmp_rh->close_handler;
          }
          else if (handler_type == REQUEST_HANDLER) {
            *handler = tmp_rh->handler;
          }
          else { /* AUTH_HANDLER */
            *auth_handler = tmp_rh->auth_handler;
          }
          *cbdata = tmp_rh->cbdata;
          mg_unlock_context(conn->ctx);
          return 1;
        }
      }
    }

    /* finally try for pattern match */
    for (tmp_rh = conn->ctx->handlers; tmp_rh != NULL;
    tmp_rh = tmp_rh->next) {
      if (tmp_rh->handler_type == handler_type) {
        if (match_prefix(tmp_rh->uri, tmp_rh->uri_len, uri) > 0) {
          if (handler_type == WEBSOCKET_HANDLER) {
            *connect_handler = tmp_rh->connect_handler;
            *ready_handler = tmp_rh->ready_handler;
            *data_handler = tmp_rh->data_handler;
            *close_handler = tmp_rh->close_handler;
          }
          else if (handler_type == REQUEST_HANDLER) {
            *handler = tmp_rh->handler;
          }
          else { /* AUTH_HANDLER */
            *auth_handler = tmp_rh->auth_handler;
          }
          *cbdata = tmp_rh->cbdata;
          mg_unlock_context(conn->ctx);
          return 1;
        }
      }
    }

    mg_unlock_context(conn->ctx);
  }
  return 0; /* none found */
}


#if defined(USE_WEBSOCKET) && defined(MG_LEGACY_INTERFACE)
static int
deprecated_websocket_connect_wrapper(const struct mg_connection *conn,
  void *cbdata)
{
  struct mg_callbacks *pcallbacks = (struct mg_callbacks *)cbdata;
  if (pcallbacks->websocket_connect) {
    return pcallbacks->websocket_connect(conn);
  }
  /* No handler set - assume "OK" */
  return 0;
}


static void
deprecated_websocket_ready_wrapper(struct mg_connection *conn, void *cbdata)
{
  struct mg_callbacks *pcallbacks = (struct mg_callbacks *)cbdata;
  if (pcallbacks->websocket_ready) {
    pcallbacks->websocket_ready(conn);
  }
}


static int
deprecated_websocket_data_wrapper(struct mg_connection *conn,
  int bits,
  char *data,
  size_t len,
  void *cbdata)
{
  struct mg_callbacks *pcallbacks = (struct mg_callbacks *)cbdata;
  if (pcallbacks->websocket_data) {
    return pcallbacks->websocket_data(conn, bits, data, len);
  }
  /* No handler set - assume "OK" */
  return 1;
}
#endif


/* This is the heart of the Civetweb's logic.
* This function is called when the request is read, parsed and validated,
* and Civetweb must decide what action to take: serve a file, or
* a directory, or call embedded function, etcetera. */
static void
handle_request(struct mg_connection *conn)
{
  if (conn) {
    struct mg_request_info *ri = &conn->request_info;
    char path[PATH_MAX];
    int uri_len, ssl_index;
    int is_found = 0, is_script_resource = 0, is_websocket_request = 0,
      is_put_or_delete_request = 0, is_callback_resource = 0;
    int i;
    struct file file = STRUCT_FILE_INITIALIZER;
    mg_request_handler callback_handler = NULL;
    mg_websocket_connect_handler ws_connect_handler = NULL;
    mg_websocket_ready_handler ws_ready_handler = NULL;
    mg_websocket_data_handler ws_data_handler = NULL;
    mg_websocket_close_handler ws_close_handler = NULL;
    void *callback_data = NULL;
    mg_authorization_handler auth_handler = NULL;
    void *auth_callback_data = NULL;
#if !defined(NO_FILES)
    time_t curtime = time(NULL);
    char date[64];
#endif

    path[0] = 0;

    if (!ri) {
      return;
    }

    /* 1. get the request url */
    /* 1.1. split into url and query string */
    if ((conn->request_info.query_string = strchr(ri->request_uri, '?'))
      != NULL) {
      *((char *)conn->request_info.query_string++) = '\0';
    }
    uri_len = (int)strlen(ri->local_uri);

    /* 1.2. decode url (if config says so) */
    if (should_decode_url(conn)) {
      mg_url_decode(
        ri->local_uri, uri_len, (char *)ri->local_uri, uri_len + 1, 0);
    }

    /* 1.3. clean URIs, so a path like allowed_dir/../forbidden_file is
    * not
    * possible */
    remove_double_dots_and_double_slashes((char *)ri->local_uri);

    /* step 1. completed, the url is known now */
    DEBUG_TRACE("URL: %s", ri->local_uri);

    /* 2. do a https redirect, if required */
    if (!conn->client.is_ssl && conn->client.ssl_redir) {
      ssl_index = get_first_ssl_listener_index(conn->ctx);
      if (ssl_index >= 0) {
        redirect_to_https_port(conn, ssl_index);
      }
      else {
        /* A http to https forward port has been specified,
        * but no https port to forward to. */
        send_http_error(conn,
          503,
          "%s",
          "Error: SSL forward not configured properly");
        mg_cry(conn, "Can not redirect to SSL, no SSL port available");
      }
      return;
    }

    /* 3. if this ip has limited speed, set it for this connection */
    conn->throttle = set_throttle(conn->ctx->config[THROTTLE],
      get_remote_ip(conn),
      ri->local_uri);

    /* 4. call a "handle everything" callback, if registered */
    if (conn->ctx->callbacks.begin_request != NULL) {
      /* Note that since V1.7 the "begin_request" function is called
      * before an authorization check. If an authorization check is
      * required, use a request_handler instead. */
      i = conn->ctx->callbacks.begin_request(conn);
      if (i > 0) {
        /* callback already processed the request. Store the
        return value as a status code for the access log. */
        conn->status_code = i;
        return;
      }
      else if (i == 0) {
        /* civetweb should process the request */
      }
      else {
        /* unspecified - may change with the next version */
        return;
      }
    }

    /* request not yet handled by a handler or redirect, so the request
    * is processed here */

    /* 5. interpret the url to find out how the request must be handled
    */
    /* 5.1. first test, if the request targets the regular http(s)://
    * protocol namespace or the websocket ws(s):// protocol namespace.
    */
    is_websocket_request = is_websocket_protocol(conn);

    /* 5.2. check if the request will be handled by a callback */
    if (get_request_handler(conn,
      is_websocket_request ? WEBSOCKET_HANDLER
      : REQUEST_HANDLER,
      &callback_handler,
      &ws_connect_handler,
      &ws_ready_handler,
      &ws_data_handler,
      &ws_close_handler,
      NULL,
      &callback_data)) {
      /* 5.2.1. A callback will handle this request. All requests
      * handled
      * by a callback have to be considered as requests to a script
      * resource. */
      is_callback_resource = 1;
      is_script_resource = 1;
      is_put_or_delete_request = is_put_or_delete_method(conn);
    }
    else {
    no_callback_resource:
      /* 5.2.2. No callback is responsible for this request. The URI
      * addresses a file based resource (static content or Lua/cgi
      * scripts in the file system). */
      is_callback_resource = 0;
      interpret_uri(conn,
        path,
        sizeof(path),
        &file,
        &is_found,
        &is_script_resource,
        &is_websocket_request,
        &is_put_or_delete_request);
    }

    /* 6. authorization check */
    /* 6.1. a custom authorization handler is installed */
    if (get_request_handler(conn,
      AUTH_HANDLER,
      NULL,
      NULL,
      NULL,
      NULL,
      NULL,
      &auth_handler,
      &auth_callback_data)) {
      if (!auth_handler(conn, auth_callback_data)) {
        return;
      }
    }
    else if (is_put_or_delete_request && !is_script_resource
      && !is_callback_resource) {
      /* 6.2. this request is a PUT/DELETE to a real file */
      /* 6.2.1. thus, the server must have real files */
#if defined(NO_FILES)
      if (1) {
#else
      if (conn->ctx->config[DOCUMENT_ROOT] == NULL) {
#endif
        /* This server does not have any real files, thus the
        * PUT/DELETE methods are not valid. */
        send_http_error(conn,
          405,
          "%s method not allowed",
          conn->request_info.request_method);
        return;
      }

#if !defined(NO_FILES)
      /* 6.2.2. Check if put authorization for static files is available.
      */
      if (!is_authorized_for_put(conn)) {
        send_authorization_request(conn);
        return;
      }
#endif

      }
    else {
      /* 6.3. This is either a OPTIONS, GET, HEAD or POST request,
      * or it is a PUT or DELETE request to a resource that does not
      * correspond to a file. Check authorization. */
      if (!check_authorization(conn, path)) {
        send_authorization_request(conn);
        return;
      }
    }

    /* request is authorized or does not need authorization */

    /* 7. check if there are request handlers for this uri */
    if (is_callback_resource) {
      if (!is_websocket_request) {
        i = callback_handler(conn, callback_data);
        if (i > 0) {
          /* Do nothing, callback has served the request. Store
          * the
          * return value as status code for the log and discard
          * all
          * data from the client not used by the callback. */
          conn->status_code = i;
          discard_unread_request_data(conn);
        }
        else {
          /* TODO (high): what if the handler did NOT handle the
          * request */
          /* The last version did handle this as a file request,
          * but
          * since a file request is not always a script resource,
          * the authorization check might be different */
          interpret_uri(conn,
            path,
            sizeof(path),
            &file,
            &is_found,
            &is_script_resource,
            &is_websocket_request,
            &is_put_or_delete_request);
          callback_handler = NULL;

          /* TODO (very low): goto is deprecated but for the
          * moment,
          * a goto is simpler than some curious loop. */
          /* The situation "callback does not handle the request"
          * needs to be reconsidered anyway. */
          goto no_callback_resource;
        }
      }
      else {
#if defined(USE_WEBSOCKET)
        handle_websocket_request(conn,
          path,
          is_callback_resource,
          ws_connect_handler,
          ws_ready_handler,
          ws_data_handler,
          ws_close_handler,
          callback_data);
#endif
      }
      return;
    }

    /* 8. handle websocket requests */
#if defined(USE_WEBSOCKET)
    if (is_websocket_request) {
      if (is_script_resource) {
        /* Websocket Lua script */
        handle_websocket_request(conn,
          path,
          0 /* Lua Script */,
          NULL,
          NULL,
          NULL,
          NULL,
          &conn->ctx->callbacks);
      }
      else {
#if defined(MG_LEGACY_INTERFACE)
        handle_websocket_request(
          conn,
          path,
          !is_script_resource /* could be deprecated global callback */,
          deprecated_websocket_connect_wrapper,
          deprecated_websocket_ready_wrapper,
          deprecated_websocket_data_wrapper,
          NULL,
          &conn->ctx->callbacks);
#else
        send_http_error(conn, 404, "%s", "Not found");
#endif
      }
      return;
    }
    else
#endif

#if defined(NO_FILES)
      /* 9a. In case the server uses only callbacks, this uri is
      * unknown.
      * Then, all request handling ends here. */
      send_http_error(conn, 404, "%s", "Not Found");

#else
      /* 9b. This request is either for a static file or resource handled
      * by a script file. Thus, a DOCUMENT_ROOT must exist. */
      if (conn->ctx->config[DOCUMENT_ROOT] == NULL) {
        send_http_error(conn, 404, "%s", "Not Found");
        return;
      }

    /* 10. File is handled by a script. */
    if (is_script_resource) {
      handle_file_based_request(conn, path, &file);
      return;
    }

    /* 11. Handle put/delete/mkcol requests */
    if (is_put_or_delete_request) {
      /* 11.1. PUT method */
      if (!strcmp(ri->request_method, "PUT")) {
        put_file(conn, path);
        return;
      }
      /* 11.2. DELETE method */
      if (!strcmp(ri->request_method, "DELETE")) {
        delete_file(conn, path);
        return;
      }
      /* 11.3. MKCOL method */
      if (!strcmp(ri->request_method, "MKCOL")) {
        mkcol(conn, path);
        return;
      }
      /* 11.4. PATCH method
      * This method is not supported for static resources,
      * only for scripts (Lua, CGI) and callbacks. */
      send_http_error(conn,
        405,
        "%s method not allowed",
        conn->request_info.request_method);
      return;
    }

    /* 11. File does not exist, or it was configured that it should be
    * hidden */
    if (!is_found || (must_hide_file(conn, path))) {
      send_http_error(conn, 404, "%s", "Not found");
      return;
    }

    /* 12. Directory uris should end with a slash */
    if (file.is_directory && ri->local_uri[uri_len - 1] != '/') {
      gmt_time_string(date, sizeof(date), &curtime);
      mg_printf(conn,
        "HTTP/1.1 301 Moved Permanently\r\n"
        "Location: %s/\r\n"
        "Date: %s\r\n"
        /* "Cache-Control: private\r\n" (= default) */
        "Content-Length: 0\r\n"
        "Connection: %s\r\n\r\n",
        ri->request_uri,
        date,
        suggest_connection_header(conn));
      return;
    }

    /* 13. Handle other methods than GET/HEAD */
    /* 13.1. Handle PROPFIND */
    if (!strcmp(ri->request_method, "PROPFIND")) {
      handle_propfind(conn, path, &file);
      return;
    }
    /* 13.2. Handle OPTIONS for files */
    if (!strcmp(ri->request_method, "OPTIONS")) {
      /* This standard handler is only used for real files.
      * Scripts should support the OPTIONS method themselves, to allow a
      * maximum flexibility.
      * Lua and CGI scripts may fully support CORS this way (including
      * preflights). */
      send_options(conn);
      return;
    }
    /* 13.3. everything but GET and HEAD (e.g. POST) */
    if (0 != strcmp(ri->request_method, "GET")
      && 0 != strcmp(ri->request_method, "HEAD")) {
      send_http_error(conn,
        405,
        "%s method not allowed",
        conn->request_info.request_method);
      return;
    }

    /* 14. directories */
    if (file.is_directory) {
      if (substitute_index_file(conn, path, sizeof(path), &file)) {
        /* 14.1. use a substitute file */
        /* TODO (high): substitute index may be a script resource.
        * define what should be possible in this case. */
      }
      else {
        /* 14.2. no substitute file */
        if (!mg_strcasecmp(conn->ctx->config[ENABLE_DIRECTORY_LISTING],
          "yes")) {
          handle_directory_request(conn, path);
        }
        else {
          send_http_error(conn,
            403,
            "%s",
            "Error: Directory listing denied");
        }
        return;
      }
    }

    handle_file_based_request(conn, path, &file);
#endif /* !defined(NO_FILES) */

#if 0
    /* Perform redirect and auth checks before calling begin_request()
    * handler.
    * Otherwise, begin_request() would need to perform auth checks and
    * redirects. */
#endif
    }
  return;
  }


static void
handle_file_based_request(struct mg_connection *conn,
  const char *path,
struct file *file)
{
  if (!conn || !conn->ctx) {
    return;
  }

  if (0) {
#ifdef USE_LUA
  }
  else if (match_prefix(conn->ctx->config[LUA_SERVER_PAGE_EXTENSIONS],
    strlen(
      conn->ctx->config[LUA_SERVER_PAGE_EXTENSIONS]),
    path) > 0) {
    /* Lua server page: an SSI like page containing mostly plain html
    * code
    * plus some tags with server generated contents. */
    handle_lsp_request(conn, path, file, NULL);
  }
  else if (match_prefix(conn->ctx->config[LUA_SCRIPT_EXTENSIONS],
    strlen(conn->ctx->config[LUA_SCRIPT_EXTENSIONS]),
    path) > 0) {
    /* Lua in-server module script: a CGI like script used to generate
    * the
    * entire reply. */
    mg_exec_lua_script(conn, path, NULL);
#endif
#if defined(USE_DUKTAPE)
  }
  else if (match_prefix(conn->ctx->config[DUKTAPE_SCRIPT_EXTENSIONS],
    strlen(
      conn->ctx->config[DUKTAPE_SCRIPT_EXTENSIONS]),
    path) > 0) {
    /* Call duktape to generate the page */
    mg_exec_duktape_script(conn, path);
#endif
#if !defined(NO_CGI)
  }
  else if (match_prefix(conn->ctx->config[CGI_EXTENSIONS],
    strlen(conn->ctx->config[CGI_EXTENSIONS]),
    path) > 0) {
    /* CGI scripts may support all HTTP methods */
    handle_cgi_request(conn, path);
#endif /* !NO_CGI */
  }
  else if (match_prefix(conn->ctx->config[SSI_EXTENSIONS],
    strlen(conn->ctx->config[SSI_EXTENSIONS]),
    path) > 0) {
    handle_ssi_file_request(conn, path, file);
  }
  else if ((!conn->in_error_handler) && is_not_modified(conn, file)) {
    /* Send 304 "Not Modified" - this must not send any body data */
    send_http_error(conn, 304, "%s", "");
  }
  else {
    handle_static_file_request(conn, path, file, NULL);
  }
}


static void
close_all_listening_sockets(struct mg_context *ctx)
{
  unsigned int i;
  if (!ctx) {
    return;
  }

  for (i = 0; i < ctx->num_listening_sockets; i++) {
    closesocket(ctx->listening_sockets[i].sock);
    ctx->listening_sockets[i].sock = INVALID_SOCKET;
  }
  mg_free(ctx->listening_sockets);
  ctx->listening_sockets = NULL;
  mg_free(ctx->listening_ports);
  ctx->listening_ports = NULL;
}


/* Valid listening port specification is: [ip_address:]port[s]
* Examples for IPv4: 80, 443s, 127.0.0.1:3128, 1.2.3.4:8080s
* Examples for IPv6: [::]:80, [::1]:80,
*   [FEDC:BA98:7654:3210:FEDC:BA98:7654:3210]:443s
*   see https://tools.ietf.org/html/rfc3513#section-2.2 */
static int
parse_port_string(const struct vec *vec, struct socket *so)
{
  unsigned int a, b, c, d, port;
  int ch, len;
#if defined(USE_IPV6)
  char buf[100] = { 0 };
#endif

  /* MacOS needs that. If we do not zero it, subsequent bind() will fail.
  * Also, all-zeroes in the socket address means binding to all addresses
  * for both IPv4 and IPv6 (INADDR_ANY and IN6ADDR_ANY_INIT). */
  memset(so, 0, sizeof(*so));
  so->lsa.sin.sin_family = AF_INET;

  if (sscanf(vec->ptr, "%u.%u.%u.%u:%u%n", &a, &b, &c, &d, &port, &len)
    == 5) {
    /* Bind to a specific IPv4 address, e.g. 192.168.1.5:8080 */
    so->lsa.sin.sin_addr.s_addr =
      htonl((a << 24) | (b << 16) | (c << 8) | d);
    so->lsa.sin.sin_port = htons((uint16_t)port);
#if defined(USE_IPV6)
  }
  else if (sscanf(vec->ptr, "[%49[^]]]:%u%n", buf, &port, &len) == 2
    && mg_inet_pton(
      AF_INET6, buf, &so->lsa.sin6, sizeof(so->lsa.sin6))) {
    /* IPv6 address, examples: see above */
    /* so->lsa.sin6.sin6_family = AF_INET6; already set by mg_inet_pton
    */
    so->lsa.sin6.sin6_port = htons((uint16_t)port);
#endif
  }
  else if (sscanf(vec->ptr, "%u%n", &port, &len) == 1) {
    /* If only port is specified, bind to IPv4, INADDR_ANY */
    so->lsa.sin.sin_port = htons((uint16_t)port);
  }
  else {
    /* Parsing failure. Make port invalid. */
    port = 0;
    len = 0;
  }

  /* sscanf and the option splitting code ensure the following condition
  */
  if ((len < 0) && ((unsigned)len >(unsigned)vec->len)) {
    return 0;
  }
  ch = vec->ptr[len]; /* Next character after the port number */
  so->is_ssl = (ch == 's');
  so->ssl_redir = (ch == 'r');

  /* Make sure the port is valid and vector ends with 's', 'r' or ',' */
  return is_valid_port(port)
    && (ch == '\0' || ch == 's' || ch == 'r' || ch == ',');
}


static int
set_ports_option(struct mg_context *ctx)
{
  const char *list;
  int on = 1;
#if defined(USE_IPV6)
  int off = 0;
#endif
  struct vec vec;
  struct socket so, *ptr;

  in_port_t *portPtr;
  union usa usa;
  socklen_t len;

  int portsTotal = 0;
  int portsOk = 0;

  if (!ctx) {
    return 0;
  }

  memset(&so, 0, sizeof(so));
  memset(&usa, 0, sizeof(usa));
  len = sizeof(usa);
  list = ctx->config[LISTENING_PORTS];
  while ((list = next_option(list, &vec, NULL)) != NULL) {

    portsTotal++;

    if (!parse_port_string(&vec, &so)) {
      mg_cry(fc(ctx),
        "%.*s: invalid port spec (entry %i). Expecting list of: %s",
        (int)vec.len,
        vec.ptr,
        portsTotal,
        "[IP_ADDRESS:]PORT[s|r]");
      continue;
    }

    if (so.is_ssl && ctx->ssl_ctx == NULL) {

      mg_cry(fc(ctx),
        "Cannot add SSL socket (entry %i). Is -ssl_certificate "
        "option set?",
        portsTotal);
      continue;
    }

    if ((so.sock = socket(so.lsa.sa.sa_family, SOCK_STREAM, 6))
      == INVALID_SOCKET) {

      mg_cry(fc(ctx), "cannot create socket (entry %i)", portsTotal);
      continue;
    }

#ifdef _WIN32
    /* Windows SO_REUSEADDR lets many procs binds to a
    * socket, SO_EXCLUSIVEADDRUSE makes the bind fail
    * if someone already has the socket -- DTL */
    /* NOTE: If SO_EXCLUSIVEADDRUSE is used,
    * Windows might need a few seconds before
    * the same port can be used again in the
    * same process, so a short Sleep may be
    * required between mg_stop and mg_start.
    */
    if (setsockopt(so.sock,
      SOL_SOCKET,
      SO_EXCLUSIVEADDRUSE,
      (SOCK_OPT_TYPE)&on,
      sizeof(on)) != 0) {

      mg_cry(fc(ctx),
        "cannot set socket option SO_EXCLUSIVEADDRUSE (entry %i)",
        portsTotal);
    }
#else
    if (setsockopt(so.sock,
      SOL_SOCKET,
      SO_REUSEADDR,
      (SOCK_OPT_TYPE)&on,
      sizeof(on)) != 0) {

      mg_cry(fc(ctx),
        "cannot set socket option SO_REUSEADDR (entry %i)",
        portsTotal);
    }
#endif

#if defined(USE_IPV6)
    if (so.lsa.sa.sa_family == AF_INET6
      && setsockopt(so.sock,
        IPPROTO_IPV6,
        IPV6_V6ONLY,
        (void *)&off,
        sizeof(off)) != 0) {

      mg_cry(fc(ctx),
        "cannot set socket option IPV6_V6ONLY (entry %i)",
        portsTotal);
    }
#endif

    if (so.lsa.sa.sa_family == AF_INET) {

      len = sizeof(so.lsa.sin);
      if (bind(so.sock, &so.lsa.sa, len) != 0) {
        mg_cry(fc(ctx),
          "cannot bind to %.*s: %d (%s)",
          (int)vec.len,
          vec.ptr,
          (int)ERRNO,
          strerror(errno));
        closesocket(so.sock);
        so.sock = INVALID_SOCKET;
        continue;
      }
    }
#if defined(USE_IPV6)
    else if (so.lsa.sa.sa_family == AF_INET6) {

      len = sizeof(so.lsa.sin6);
      if (bind(so.sock, &so.lsa.sa, len) != 0) {
        mg_cry(fc(ctx),
          "cannot bind to IPv6 %.*s: %d (%s)",
          (int)vec.len,
          vec.ptr,
          (int)ERRNO,
          strerror(errno));
        closesocket(so.sock);
        so.sock = INVALID_SOCKET;
        continue;
      }
    }
#endif
    else {
      mg_cry(fc(ctx),
        "cannot bind: address family not supported (entry %i)",
        portsTotal);
      continue;
    }

    if (listen(so.sock, SOMAXCONN) != 0) {

      mg_cry(fc(ctx),
        "cannot listen to %.*s: %d (%s)",
        (int)vec.len,
        vec.ptr,
        (int)ERRNO,
        strerror(errno));
      closesocket(so.sock);
      so.sock = INVALID_SOCKET;
      continue;
    }

    if (getsockname(so.sock, &(usa.sa), &len) != 0) {

      int err = (int)ERRNO;
      mg_cry(fc(ctx),
        "call to getsockname failed %.*s: %d (%s)",
        (int)vec.len,
        vec.ptr,
        err,
        strerror(errno));
      closesocket(so.sock);
      so.sock = INVALID_SOCKET;
      continue;
    }

    if ((ptr = (struct socket *)
      mg_realloc(ctx->listening_sockets,
        (ctx->num_listening_sockets + 1)
        * sizeof(ctx->listening_sockets[0]))) == NULL) {

      mg_cry(fc(ctx), "%s", "Out of memory");
      closesocket(so.sock);
      so.sock = INVALID_SOCKET;
      continue;
    }

    if ((portPtr =
      (in_port_t *)mg_realloc(ctx->listening_ports,
        (ctx->num_listening_sockets + 1)
        * sizeof(ctx->listening_ports[0])))
      == NULL) {

      mg_cry(fc(ctx), "%s", "Out of memory");
      closesocket(so.sock);
      so.sock = INVALID_SOCKET;
      mg_free(ptr);
      continue;
    }

    set_close_on_exec(so.sock, fc(ctx));
    ctx->listening_sockets = ptr;
    ctx->listening_sockets[ctx->num_listening_sockets] = so;
    ctx->listening_ports = portPtr;
    ctx->listening_ports[ctx->num_listening_sockets] =
      ntohs(usa.sin.sin_port);
    ctx->num_listening_sockets++;
    portsOk++;
  }

  if (portsOk != portsTotal) {
    close_all_listening_sockets(ctx);
    portsOk = 0;
  }

  return portsOk;
}


static const char *
header_val(const struct mg_connection *conn, const char *header)
{
  const char *header_value;

  if ((header_value = mg_get_header(conn, header)) == NULL) {
    return "-";
  }
  else {
    return header_value;
  }
}


static void
log_access(const struct mg_connection *conn)
{
  const struct mg_request_info *ri;
  struct file fi;
  char date[64], src_addr[IP_ADDR_STR_LEN];
  struct tm *tm;

  const char *referer;
  const char *user_agent;

  char buf[4096];

  if (!conn || !conn->ctx) {
    return;
  }

  if (conn->ctx->config[ACCESS_LOG_FILE] != NULL) {
    if (mg_fopen(conn, conn->ctx->config[ACCESS_LOG_FILE], "a+", &fi)
      == 0) {
      fi.fp = NULL;
    }
  }
  else {
    fi.fp = NULL;
  }

  if (fi.fp == NULL && conn->ctx->callbacks.log_message == NULL) {
    return;
  }

  tm = localtime(&conn->conn_birth_time);
  if (tm != NULL) {
    strftime(date, sizeof(date), "%d/%b/%Y:%H:%M:%S %z", tm);
  }
  else {
    mg_strlcpy(date, "01/Jan/1970:00:00:00 +0000", sizeof(date));
    date[sizeof(date) - 1] = '\0';
  }

  ri = &conn->request_info;

  sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
  referer = header_val(conn, "Referer");
  user_agent = header_val(conn, "User-Agent");

  mg_snprintf(conn,
    NULL, /* Ignore truncation in access log */
    buf,
    sizeof(buf),
    "%s - %s [%s] \"%s %s%s%s HTTP/%s\" %d %" INT64_FMT " %s %s",
    src_addr,
    ri->remote_user == NULL ? "-" : ri->remote_user,
    date,
    ri->request_method ? ri->request_method : "-",
    ri->request_uri ? ri->request_uri : "-",
    ri->query_string ? "?" : "",
    ri->query_string ? ri->query_string : "",
    ri->http_version,
    conn->status_code,
    conn->num_bytes_sent,
    referer,
    user_agent);

  if (conn->ctx->callbacks.log_access) {
    conn->ctx->callbacks.log_access(conn, buf);
  }

  if (fi.fp) {
    flockfile(fi.fp);
    fprintf(fi.fp, "%s\n", buf);
    fflush(fi.fp);
    funlockfile(fi.fp);
    mg_fclose(&fi);
  }
}


/* Verify given socket address against the ACL.
* Return -1 if ACL is malformed, 0 if address is disallowed, 1 if allowed.
*/
static int
check_acl(struct mg_context *ctx, uint32_t remote_ip)
{
  int allowed, flag;
  uint32_t net, mask;
  struct vec vec;

  if (ctx) {
    const char *list = ctx->config[ACCESS_CONTROL_LIST];

    /* If any ACL is set, deny by default */
    allowed = list == NULL ? '+' : '-';

    while ((list = next_option(list, &vec, NULL)) != NULL) {
      flag = vec.ptr[0];
      if ((flag != '+' && flag != '-')
        || parse_net(&vec.ptr[1], &net, &mask) == 0) {
        mg_cry(fc(ctx),
          "%s: subnet must be [+|-]x.x.x.x[/x]",
          __func__);
        return -1;
      }

      if (net == (remote_ip & mask)) {
        allowed = flag;
      }
    }

    return allowed == '+';
  }
  return -1;
}


#if !defined(_WIN32)
static int
set_uid_option(struct mg_context *ctx)
{
  struct passwd *pw;
  if (ctx) {
    const char *uid = ctx->config[RUN_AS_USER];
    int success = 0;

    if (uid == NULL) {
      success = 1;
    }
    else {
      if ((pw = getpwnam(uid)) == NULL) {
        mg_cry(fc(ctx), "%s: unknown user [%s]", __func__, uid);
      }
      else if (setgid(pw->pw_gid) == -1) {
        mg_cry(fc(ctx),
          "%s: setgid(%s): %s",
          __func__,
          uid,
          strerror(errno));
      }
      else if (setgroups(0, NULL)) {
        mg_cry(fc(ctx),
          "%s: setgroups(): %s",
          __func__,
          strerror(errno));
      }
      else if (setuid(pw->pw_uid) == -1) {
        mg_cry(fc(ctx),
          "%s: setuid(%s): %s",
          __func__,
          uid,
          strerror(errno));
      }
      else {
        success = 1;
      }
    }

    return success;
  }
  return 0;
}
#endif /* !_WIN32 */


static void
tls_dtor(void *key)
{
  struct mg_workerTLS *tls = (struct mg_workerTLS *)key;
  /* key == pthread_getspecific(sTlsKey); */

  if (tls) {
    if (tls->is_master == 2) {
      tls->is_master = -3; /* Mark memory as dead */
      mg_free(tls);
    }
  }
  pthread_setspecific(sTlsKey, NULL);
}


#if !defined(NO_SSL)

/* Must be set if sizeof(pthread_t) > sizeof(unsigned long) */
static unsigned long
ssl_id_callback(void)
{
#ifdef _WIN32
  return GetCurrentThreadId();
#else

#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunreachable-code"
  /* For every compiler, either "sizeof(pthread_t) > sizeof(unsigned long)"
  * or not, so one of the two conditions will be unreachable by construction.
  * Unfortunately the C standard does not define a way to check this at
  * compile time, since the #if preprocessor conditions can not use the sizeof
  * operator as an argument. */
#endif

  if (sizeof(pthread_t) > sizeof(unsigned long)) {
    /* This is the problematic case for CRYPTO_set_id_callback:
    * The OS pthread_t can not be cast to unsigned long. */
    struct mg_workerTLS *tls =
      (struct mg_workerTLS *)pthread_getspecific(sTlsKey);
    if (tls == NULL) {
      /* SSL called from an unknown thread: Create some thread index.
      */
      tls = (struct mg_workerTLS *)mg_malloc(sizeof(struct mg_workerTLS));
      tls->is_master = -2; /* -2 means "3rd party thread" */
      tls->thread_idx = (unsigned)mg_atomic_inc(&thread_idx_max);
      pthread_setspecific(sTlsKey, tls);
    }
    return tls->thread_idx;
  }
  else {
    return (unsigned long)pthread_self();
  }

#ifdef __clang__
#pragma clang diagnostic pop
#endif

#endif
}

static pthread_mutex_t *ssl_mutexes;


static int
sslize(struct mg_connection *conn, SSL_CTX *s, int(*func)(SSL *))
{
  int ret, err;
  if (!conn) {
    return 0;
  }

  conn->ssl = SSL_new(s);
  if (conn->ssl == NULL) {
    return 0;
  }

  ret = SSL_set_fd(conn->ssl, conn->client.sock);
  if (ret != 1) {
    err = SSL_get_error(conn->ssl, ret);
    (void)err; /* TODO: set some error message */
    SSL_free(conn->ssl);
    conn->ssl = NULL;
    /* maybe not? CRYPTO_cleanup_all_ex_data(); */
    /* see https://wiki.openssl.org/index.php/Talk:Library_Initialization */
    ERR_remove_state(0);
    return 0;
  }

  ret = func(conn->ssl);
  if (ret != 1) {
    err = SSL_get_error(conn->ssl, ret);
    (void)err; /* TODO: set some error message */
    SSL_free(conn->ssl);
    conn->ssl = NULL;
    /* maybe not? CRYPTO_cleanup_all_ex_data(); */
    /* see https://wiki.openssl.org/index.php/Talk:Library_Initialization */
    ERR_remove_state(0);
    return 0;
  }

  return 1;
}


/* Return OpenSSL error message (from CRYPTO lib) */
static const char *
ssl_error(void)
{
  unsigned long err;
  err = ERR_get_error();
  return err == 0 ? "" : ERR_error_string(err, NULL);
}


static void
ssl_locking_callback(int mode, int mutex_num, const char *file, int line)
{
  (void)line;
  (void)file;

  if (mode & 1) {
    /* 1 is CRYPTO_LOCK */
    (void)pthread_mutex_lock(&ssl_mutexes[mutex_num]);
  }
  else {
    (void)pthread_mutex_unlock(&ssl_mutexes[mutex_num]);
  }
}


#if !defined(NO_SSL_DL)
static void *
load_dll(struct mg_context *ctx, const char *dll_name, struct ssl_func *sw)
{
  union {
    void *p;
    void(*fp)(void);
  } u;
  void *dll_handle;
  struct ssl_func *fp;

  if ((dll_handle = dlopen(dll_name, RTLD_LAZY)) == NULL) {
    mg_cry(fc(ctx), "%s: cannot load %s", __func__, dll_name);
    return NULL;
  }

  for (fp = sw; fp->name != NULL; fp++) {
#ifdef _WIN32
    /* GetProcAddress() returns pointer to function */
    u.fp = (void(*)(void))dlsym(dll_handle, fp->name);
#else
    /* dlsym() on UNIX returns void *. ISO C forbids casts of data
    * pointers to function pointers. We need to use a union to make a
    * cast. */
    u.p = dlsym(dll_handle, fp->name);
#endif /* _WIN32 */
    if (u.fp == NULL) {
      mg_cry(fc(ctx),
        "%s: %s: cannot find %s",
        __func__,
        dll_name,
        fp->name);
      dlclose(dll_handle);
      return NULL;
    }
    else {
      fp->ptr = u.fp;
    }
  }

  return dll_handle;
}


static void *ssllib_dll_handle;    /* Store the ssl library handle. */
static void *cryptolib_dll_handle; /* Store the crypto library handle. */

#endif /* NO_SSL_DL */


#if defined(SSL_ALREADY_INITIALIZED)
static int cryptolib_users = 1; /* Reference counter for crypto library. */
#else
static int cryptolib_users = 0; /* Reference counter for crypto library. */
#endif


static int
initialize_ssl(struct mg_context *ctx)
{
  int i;
  size_t size;

#if !defined(NO_SSL_DL)
  if (!cryptolib_dll_handle) {
    cryptolib_dll_handle = load_dll(ctx, CRYPTO_LIB, crypto_sw);
    if (!cryptolib_dll_handle) {
      return 0;
    }
  }
#endif /* NO_SSL_DL */

  if (mg_atomic_inc(&cryptolib_users) > 1) {
    return 1;
  }

  /* Initialize locking callbacks, needed for thread safety.
  * http://www.openssl.org/support/faq.html#PROG1
  */
  i = CRYPTO_num_locks();
  if (i < 0) {
    i = 0;
  }
  size = sizeof(pthread_mutex_t) * ((size_t)(i));
  if ((ssl_mutexes = (pthread_mutex_t *)mg_malloc(size)) == NULL) {
    mg_cry(fc(ctx),
      "%s: cannot allocate mutexes: %s",
      __func__,
      ssl_error());
    return 0;
  }

  for (i = 0; i < CRYPTO_num_locks(); i++) {
    pthread_mutex_init(&ssl_mutexes[i], &pthread_mutex_attr);
  }

  CRYPTO_set_locking_callback(&ssl_locking_callback);
  CRYPTO_set_id_callback(&ssl_id_callback);

  return 1;
}


static int
ssl_use_pem_file(struct mg_context *ctx, const char *pem)
{
  if (SSL_CTX_use_certificate_file(ctx->ssl_ctx, pem, 1) == 0) {
    mg_cry(fc(ctx),
      "%s: cannot open certificate file %s: %s",
      __func__,
      pem,
      ssl_error());
    return 0;
  }

  /* could use SSL_CTX_set_default_passwd_cb_userdata */
  if (SSL_CTX_use_PrivateKey_file(ctx->ssl_ctx, pem, 1) == 0) {
    mg_cry(fc(ctx),
      "%s: cannot open private key file %s: %s",
      __func__,
      pem,
      ssl_error());
    return 0;
  }

  if (SSL_CTX_check_private_key(ctx->ssl_ctx) == 0) {
    mg_cry(fc(ctx),
      "%s: certificate and private key do not match: %s",
      __func__,
      pem);
    return 0;
  }

  if (SSL_CTX_use_certificate_chain_file(ctx->ssl_ctx, pem) == 0) {
    mg_cry(fc(ctx),
      "%s: cannot use certificate chain file %s: %s",
      __func__,
      pem,
      ssl_error());
    return 0;
  }
  return 1;
}


static long
ssl_get_protocol(int version_id)
{
  long ret = SSL_OP_ALL;
  if (version_id > 0)
    ret |= SSL_OP_NO_SSLv2;
  if (version_id > 1)
    ret |= SSL_OP_NO_SSLv3;
  if (version_id > 2)
    ret |= SSL_OP_NO_TLSv1;
  if (version_id > 3)
    ret |= SSL_OP_NO_TLSv1_1;
  return ret;
}


/* Dynamically load SSL library. Set up ctx->ssl_ctx pointer. */
static int
set_ssl_option(struct mg_context *ctx)
{
  const char *pem;
  int callback_ret;
  int should_verify_peer;
  const char *ca_path;
  const char *ca_file;
  int use_default_verify_paths;
  int verify_depth;
  time_t now_rt = time(NULL);
  struct timespec now_mt;
  md5_byte_t ssl_context_id[16];
  md5_state_t md5state;
  int protocol_ver;

  /* If PEM file is not specified and the init_ssl callback
  * is not specified, skip SSL initialization. */
  if (!ctx) {
    return 0;
  }
  if ((pem = ctx->config[SSL_CERTIFICATE]) == NULL
    && ctx->callbacks.init_ssl == NULL) {
    return 1;
  }

  if (!initialize_ssl(ctx)) {
    return 0;
  }

#if !defined(NO_SSL_DL)
  if (!ssllib_dll_handle) {
    ssllib_dll_handle = load_dll(ctx, SSL_LIB, ssl_sw);
    if (!ssllib_dll_handle) {
      return 0;
    }
  }
#endif /* NO_SSL_DL */

  /* Initialize SSL library */
  SSL_library_init();
  SSL_load_error_strings();

  if ((ctx->ssl_ctx = SSL_CTX_new(SSLv23_server_method())) == NULL) {
    mg_cry(fc(ctx), "SSL_CTX_new (server) error: %s", ssl_error());
    return 0;
  }

  SSL_CTX_clear_options(ctx->ssl_ctx,
    SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1
    | SSL_OP_NO_TLSv1_1);
  protocol_ver = atoi(ctx->config[SSL_PROTOCOL_VERSION]);
  SSL_CTX_set_options(ctx->ssl_ctx, ssl_get_protocol(protocol_ver));
  SSL_CTX_set_options(ctx->ssl_ctx, SSL_OP_SINGLE_DH_USE);
  SSL_CTX_set_ecdh_auto(ctx->ssl_ctx, 1);

  /* If a callback has been specified, call it. */
  callback_ret =
    (ctx->callbacks.init_ssl == NULL)
    ? 0
    : (ctx->callbacks.init_ssl(ctx->ssl_ctx, ctx->user_data));

  /* If callback returns 0, civetweb sets up the SSL certificate.
  * If it returns 1, civetweb assumes the calback already did this.
  * If it returns -1, initializing ssl fails. */
  if (callback_ret < 0) {
    mg_cry(fc(ctx), "SSL callback returned error: %i", callback_ret);
    return 0;
  }
  if (callback_ret > 0) {
    if (pem != NULL) {
      (void)SSL_CTX_use_certificate_chain_file(ctx->ssl_ctx, pem);
    }
    return 1;
  }

  /* Use some UID as session context ID. */
  md5_init(&md5state);
  md5_append(&md5state, (const md5_byte_t *)&now_rt, sizeof(now_rt));
  clock_gettime(CLOCK_MONOTONIC, &now_mt);
  md5_append(&md5state, (const md5_byte_t *)&now_mt, sizeof(now_mt));
  md5_append(&md5state,
    (const md5_byte_t *)ctx->config[LISTENING_PORTS],
    strlen(ctx->config[LISTENING_PORTS]));
  md5_append(&md5state, (const md5_byte_t *)ctx, sizeof(*ctx));
  md5_finish(&md5state, ssl_context_id);

  SSL_CTX_set_session_id_context(ctx->ssl_ctx,
    (const unsigned char *)&ssl_context_id,
    sizeof(ssl_context_id));

  if (pem != NULL) {
    if (!ssl_use_pem_file(ctx, pem)) {
      return 0;
    }
  }

  should_verify_peer =
    (ctx->config[SSL_DO_VERIFY_PEER] != NULL)
    && (mg_strcasecmp(ctx->config[SSL_DO_VERIFY_PEER], "yes") == 0);

  use_default_verify_paths =
    (ctx->config[SSL_DEFAULT_VERIFY_PATHS] != NULL)
    && (mg_strcasecmp(ctx->config[SSL_DEFAULT_VERIFY_PATHS], "yes") == 0);

  if (should_verify_peer) {
    ca_path = ctx->config[SSL_CA_PATH];
    ca_file = ctx->config[SSL_CA_FILE];
    if (SSL_CTX_load_verify_locations(ctx->ssl_ctx, ca_file, ca_path)
      != 1) {
      mg_cry(fc(ctx),
        "SSL_CTX_load_verify_locations error: %s "
        "ssl_verify_peer requires setting "
        "either ssl_ca_path or ssl_ca_file. Is any of them "
        "present in "
        "the .conf file?",
        ssl_error());
      return 0;
    }

    SSL_CTX_set_verify(ctx->ssl_ctx,
      SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
      NULL);

    if (use_default_verify_paths
      && SSL_CTX_set_default_verify_paths(ctx->ssl_ctx) != 1) {
      mg_cry(fc(ctx),
        "SSL_CTX_set_default_verify_paths error: %s",
        ssl_error());
      return 0;
    }

    if (ctx->config[SSL_VERIFY_DEPTH]) {
      verify_depth = atoi(ctx->config[SSL_VERIFY_DEPTH]);
      SSL_CTX_set_verify_depth(ctx->ssl_ctx, verify_depth);
    }
  }

  if (ctx->config[SSL_CIPHER_LIST] != NULL) {
    if (SSL_CTX_set_cipher_list(ctx->ssl_ctx, ctx->config[SSL_CIPHER_LIST])
      != 1) {
      mg_cry(fc(ctx), "SSL_CTX_set_cipher_list error: %s", ssl_error());
    }
  }

  return 1;
}


static void
uninitialize_ssl(struct mg_context *ctx)
{
  int i;
  (void)ctx;

  if (mg_atomic_dec(&cryptolib_users) == 0) {

    /* Shutdown according to
    * https://wiki.openssl.org/index.php/Library_Initialization#Cleanup
    * http://stackoverflow.com/questions/29845527/how-to-properly-uninitialize-openssl
    */
    CRYPTO_set_locking_callback(NULL);
    CRYPTO_set_id_callback(NULL);
    ENGINE_cleanup();
    CONF_modules_unload(1);
    ERR_free_strings();
    EVP_cleanup();
    CRYPTO_cleanup_all_ex_data();
    ERR_remove_state(0);

    for (i = 0; i < CRYPTO_num_locks(); i++) {
      pthread_mutex_destroy(&ssl_mutexes[i]);
    }
    mg_free(ssl_mutexes);
    ssl_mutexes = NULL;
  }
}
#endif /* !NO_SSL */


static int
set_gpass_option(struct mg_context *ctx)
{
  if (ctx) {
    struct file file = STRUCT_FILE_INITIALIZER;
    const char *path = ctx->config[GLOBAL_PASSWORDS_FILE];
    if (path != NULL && !mg_stat(fc(ctx), path, &file)) {
      mg_cry(fc(ctx), "Cannot open %s: %s", path, strerror(ERRNO));
      return 0;
    }
    return 1;
  }
  return 0;
}


static int
set_acl_option(struct mg_context *ctx)
{
  return check_acl(ctx, (uint32_t)0x7f000001UL) != -1;
}


static void
reset_per_request_attributes(struct mg_connection *conn)
{
  if (!conn) {
    return;
  }
  conn->path_info = NULL;
  conn->num_bytes_sent = conn->consumed_content = 0;
  conn->status_code = -1;
  conn->is_chunked = 0;
  conn->must_close = conn->request_len = conn->throttle = 0;
  conn->request_info.content_length = -1;
  conn->request_info.remote_user = NULL;
  conn->request_info.request_method = NULL;
  conn->request_info.request_uri = NULL;
  conn->request_info.local_uri = NULL;
  conn->request_info.uri = NULL; /* TODO: cleanup uri,
                                 * local_uri and request_uri */
  conn->request_info.http_version = NULL;
  conn->request_info.num_headers = 0;
  conn->data_len = 0;
  conn->chunk_remainder = 0;
  conn->internal_error = 0;
}


static int
set_sock_timeout(SOCKET sock, int milliseconds)
{
  int r0 = 0, r1, r2;

#ifdef _WIN32
  /* Windows specific */

  DWORD tv = (DWORD)milliseconds;

#else
  /* Linux, ... (not Windows) */

  struct timeval tv;

  /* TCP_USER_TIMEOUT/RFC5482 (http://tools.ietf.org/html/rfc5482):
  * max. time waiting for the acknowledged of TCP data before the connection
  * will be forcefully closed and ETIMEDOUT is returned to the application.
  * If this option is not set, the default timeout of 20-30 minutes is used.
  */
  /* #define TCP_USER_TIMEOUT (18) */

#if defined(TCP_USER_TIMEOUT)
  unsigned int uto = (unsigned int)milliseconds;
  r0 = setsockopt(sock, 6, TCP_USER_TIMEOUT, (const void *)&uto, sizeof(uto));
#endif

  memset(&tv, 0, sizeof(tv));
  tv.tv_sec = milliseconds / 1000;
  tv.tv_usec = (milliseconds * 1000) % 1000000;

#endif /* _WIN32 */

  r1 = setsockopt(
    sock, SOL_SOCKET, SO_RCVTIMEO, (SOCK_OPT_TYPE)&tv, sizeof(tv));
  r2 = setsockopt(
    sock, SOL_SOCKET, SO_SNDTIMEO, (SOCK_OPT_TYPE)&tv, sizeof(tv));

  return r0 || r1 || r2;
}


static int
set_tcp_nodelay(SOCKET sock, int nodelay_on)
{
  if (setsockopt(sock,
    IPPROTO_TCP,
    TCP_NODELAY,
    (SOCK_OPT_TYPE)&nodelay_on,
    sizeof(nodelay_on)) != 0) {
    /* Error */
    return 1;
  }
  /* OK */
  return 0;
}


static void
close_socket_gracefully(struct mg_connection *conn)
{
#if defined(_WIN32)
  char buf[MG_BUF_LEN];
  int n;
#endif
  struct linger linger;

  if (!conn) {
    return;
  }

  /* Set linger option to avoid socket hanging out after close. This
  * prevent
  * ephemeral port exhaust problem under high QPS. */
  linger.l_onoff = 1;
  linger.l_linger = 1;

  if (setsockopt(conn->client.sock,
    SOL_SOCKET,
    SO_LINGER,
    (char *)&linger,
    sizeof(linger)) != 0) {
    mg_cry(conn,
      "%s: setsockopt(SOL_SOCKET SO_LINGER) failed: %s",
      __func__,
      strerror(ERRNO));
  }

  /* Send FIN to the client */
  shutdown(conn->client.sock, SHUT_WR);
  set_non_blocking_mode(conn->client.sock);

#if defined(_WIN32)
  /* Read and discard pending incoming data. If we do not do that and
  * close
  * the socket, the data in the send buffer may be discarded. This
  * behaviour is seen on Windows, when client keeps sending data
  * when server decides to close the connection; then when client
  * does recv() it gets no data back. */
  do {
    n = pull(
      NULL, conn, buf, sizeof(buf), 1E-10 /* TODO: allow 0 as timeout */);
  } while (n > 0);
#endif

  /* Now we know that our FIN is ACK-ed, safe to close */
  closesocket(conn->client.sock);
  conn->client.sock = INVALID_SOCKET;
}


static void
close_connection(struct mg_connection *conn)
{
  if (!conn || !conn->ctx) {
    return;
  }

#if defined(USE_LUA) && defined(USE_WEBSOCKET)
  if (conn->lua_websocket_state) {
    lua_websocket_close(conn, conn->lua_websocket_state);
    conn->lua_websocket_state = NULL;
  }
#endif

  /* call the connection_close callback if assigned */
  if ((conn->ctx->callbacks.connection_close != NULL)
    && (conn->ctx->context_type == 1)) {
    conn->ctx->callbacks.connection_close(conn);
  }

  mg_lock_connection(conn);

  conn->must_close = 1;

#ifndef NO_SSL
  if (conn->ssl != NULL) {
    /* Run SSL_shutdown twice to ensure completly close SSL connection
    */
    SSL_shutdown(conn->ssl);
    SSL_free(conn->ssl);
    /* maybe not? CRYPTO_cleanup_all_ex_data(); */
    /* see https://wiki.openssl.org/index.php/Talk:Library_Initialization */
    ERR_remove_state(0);
    conn->ssl = NULL;
  }
#endif
  if (conn->client.sock != INVALID_SOCKET) {
    close_socket_gracefully(conn);
    conn->client.sock = INVALID_SOCKET;
  }

  mg_unlock_connection(conn);
}

void
mg_close_connection(struct mg_connection *conn)
{
  struct mg_context *client_ctx = NULL;
  unsigned int i;

  if (conn == NULL) {
    return;
  }

  if (conn->ctx->context_type == 2) {
    client_ctx = conn->ctx;
    /* client context: loops must end */
    conn->ctx->stop_flag = 1;
  }

#ifndef NO_SSL
  if (conn->client_ssl_ctx != NULL) {
    SSL_CTX_free((SSL_CTX *)conn->client_ssl_ctx);
  }
#endif
  close_connection(conn);
  if (client_ctx != NULL) {
    /* join worker thread and free context */
    for (i = 0; i < client_ctx->cfg_worker_threads; i++) {
      if (client_ctx->workerthreadids[i] != 0) {
        mg_join_thread(client_ctx->workerthreadids[i]);
      }
    }
    mg_free(client_ctx->workerthreadids);
    mg_free(client_ctx);
    (void)pthread_mutex_destroy(&conn->mutex);
    mg_free(conn);
  }
}


static struct mg_connection *
mg_connect_client_impl(const struct mg_client_options *client_options,
  int use_ssl,
  char *ebuf,
  size_t ebuf_len)
{
  static struct mg_context fake_ctx;
  struct mg_connection *conn = NULL;
  SOCKET sock;
  union usa sa;

  if (!connect_socket(&fake_ctx,
    client_options->host,
    client_options->port,
    use_ssl,
    ebuf,
    ebuf_len,
    &sock,
    &sa)) {
    ;
  }
  else if ((conn = (struct mg_connection *)
    mg_calloc(1, sizeof(*conn) + MAX_REQUEST_SIZE)) == NULL) {
    mg_snprintf(NULL,
      NULL, /* No truncation check for ebuf */
      ebuf,
      ebuf_len,
      "calloc(): %s",
      strerror(ERRNO));
    closesocket(sock);
#ifndef NO_SSL
  }
  else if (use_ssl
    && (conn->client_ssl_ctx = SSL_CTX_new(SSLv23_client_method()))
    == NULL) {
    mg_snprintf(NULL,
      NULL, /* No truncation check for ebuf */
      ebuf,
      ebuf_len,
      "SSL_CTX_new error");
    closesocket(sock);
    mg_free(conn);
    conn = NULL;
#endif /* NO_SSL */

  }
  else {

#ifdef USE_IPV6
    socklen_t len = (sa.sa.sa_family == AF_INET)
      ? sizeof(conn->client.rsa.sin)
      : sizeof(conn->client.rsa.sin6);
    struct sockaddr *psa =
      (sa.sa.sa_family == AF_INET)
      ? (struct sockaddr *)&(conn->client.rsa.sin)
      : (struct sockaddr *)&(conn->client.rsa.sin6);
#else
    socklen_t len = sizeof(conn->client.rsa.sin);
    struct sockaddr *psa = (struct sockaddr *)&(conn->client.rsa.sin);
#endif

    conn->buf_size = MAX_REQUEST_SIZE;
    conn->buf = (char *)(conn + 1);
    conn->ctx = &fake_ctx;
    conn->client.sock = sock;
    conn->client.lsa = sa;

    if (getsockname(sock, psa, &len) != 0) {
      mg_cry(conn,
        "%s: getsockname() failed: %s",
        __func__,
        strerror(ERRNO));
    }

    conn->client.is_ssl = use_ssl ? 1 : 0;
    (void)pthread_mutex_init(&conn->mutex, &pthread_mutex_attr);

#ifndef NO_SSL
    if (use_ssl) {
      fake_ctx.ssl_ctx = conn->client_ssl_ctx;

      /* TODO: Check ssl_verify_peer and ssl_ca_path here.
      SSL_CTX_set_verify call is needed to switch off server
      * certificate checking, which is off by default in OpenSSL and
      on
      * in yaSSL. */

      // TODO: SSL_CTX_set_verify(conn->client_ssl_ctx,
      // SSL_VERIFY_PEER,
      // verify_ssl_server);

      if (client_options->client_cert) {
        if (!ssl_use_pem_file(&fake_ctx, client_options->client_cert)) {
          mg_snprintf(NULL,
            NULL, /* No truncation check for ebuf */
            ebuf,
            ebuf_len,
            "Can not use SSL client certificate");
          SSL_CTX_free(conn->client_ssl_ctx);
          closesocket(sock);
          mg_free(conn);
          conn = NULL;
        }
      }

      if (client_options->server_cert) {
        SSL_CTX_load_verify_locations(conn->client_ssl_ctx,
          client_options->server_cert,
          NULL);
        SSL_CTX_set_verify(conn->client_ssl_ctx, SSL_VERIFY_PEER, NULL);
      }
      else {
        SSL_CTX_set_verify(conn->client_ssl_ctx, SSL_VERIFY_NONE, NULL);
      }

      if (!sslize(conn, conn->client_ssl_ctx, SSL_connect)) {
        mg_snprintf(NULL,
          NULL, /* No truncation check for ebuf */
          ebuf,
          ebuf_len,
          "SSL connection error");
        SSL_CTX_free(conn->client_ssl_ctx);
        closesocket(sock);
        mg_free(conn);
        conn = NULL;
      }
    }
#endif
  }

  return conn;
}


CIVETWEB_API struct mg_connection *
mg_connect_client_secure(const struct mg_client_options *client_options,
  char *error_buffer,
  size_t error_buffer_size)
{
  return mg_connect_client_impl(client_options,
    1,
    error_buffer,
    error_buffer_size);
}


struct mg_connection *
  mg_connect_client(const char *host,
    int port,
    int use_ssl,
    char *error_buffer,
    size_t error_buffer_size)
{
  struct mg_client_options opts;
  memset(&opts, 0, sizeof(opts));
  opts.host = host;
  opts.port = port;
  return mg_connect_client_impl(&opts,
    use_ssl,
    error_buffer,
    error_buffer_size);
}


static const struct {
  const char *proto;
  size_t proto_len;
  unsigned default_port;
} abs_uri_protocols[] = { { "http://", 7, 80 },
{ "https://", 8, 443 },
{ "ws://", 5, 80 },
{ "wss://", 6, 443 },
{ NULL, 0, 0 } };


/* Check if the uri is valid.
* return 0 for invalid uri,
* return 1 for *,
* return 2 for relative uri,
* return 3 for absolute uri without port,
* return 4 for absolute uri with port */
static int
get_uri_type(const char *uri)
{
  int i;
  char *hostend, *portbegin, *portend;
  unsigned long port;

  /* According to the HTTP standard
  * http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html#sec5.1.2
  * URI can be an asterisk (*) or should start with slash (relative uri),
  * or it should start with the protocol (absolute uri). */
  if (uri[0] == '*' && uri[1] == '\0') {
    /* asterisk */
    return 1;
  }
  if (uri[0] == '/') {
    /* relative uri */
    return 2;
  }

  /* It could be an absolute uri: */
  /* This function only checks if the uri is valid, not if it is
  * addressing the current server. So civetweb can also be used
  * as a proxy server. */
  for (i = 0; abs_uri_protocols[i].proto != NULL; i++) {
    if (mg_strncasecmp(uri,
      abs_uri_protocols[i].proto,
      abs_uri_protocols[i].proto_len) == 0) {

      hostend = (char*)strchr(uri + abs_uri_protocols[i].proto_len, '/');
      if (!hostend) {
        return 0;
      }
      portbegin = (char*)strchr(uri + abs_uri_protocols[i].proto_len, ':');
      if (!portbegin) {
        return 3;
      }

      port = strtoul(portbegin + 1, &portend, 10);
      if ((portend != hostend) || !port || !is_valid_port(port)) {
        return 0;
      }

      return 4;
    }
  }

  return 0;
}


/* Return NULL or the relative uri at the current server */
static const char *
get_rel_url_at_current_server(const char *uri, const struct mg_connection *conn)
{
  const char *server_domain;
  size_t server_domain_len;
  size_t request_domain_len = 0;
  unsigned long port = 0;
  int i;
  const char *hostbegin = NULL;
  const char *hostend = NULL;
  const char *portbegin;
  char *portend;

  /* DNS is case insensitive, so use case insensitive string compare here
  */
  server_domain = conn->ctx->config[AUTHENTICATION_DOMAIN];
  if (!server_domain) {
    return 0;
  }
  server_domain_len = strlen(server_domain);
  if (!server_domain_len) {
    return 0;
  }

  for (i = 0; abs_uri_protocols[i].proto != NULL; i++) {
    if (mg_strncasecmp(uri,
      abs_uri_protocols[i].proto,
      abs_uri_protocols[i].proto_len) == 0) {

      hostbegin = uri + abs_uri_protocols[i].proto_len;
      hostend = strchr(hostbegin, '/');
      if (!hostend) {
        return 0;
      }
      portbegin = strchr(hostbegin, ':');
      if ((!portbegin) || (portbegin > hostend)) {
        port = abs_uri_protocols[i].default_port;
        request_domain_len = (size_t)(hostend - hostbegin);
      }
      else {
        port = strtoul(portbegin + 1, &portend, 10);
        if ((portend != hostend) || !port || !is_valid_port(port)) {
          return 0;
        }
        request_domain_len = (size_t)(portbegin - hostbegin);
      }
      /* protocol found, port set */
      break;
    }
  }

  if (!port) {
    /* port remains 0 if the protocol is not found */
    return 0;
  }

#if defined(USE_IPV6)
  if (conn->client.lsa.sa.sa_family == AF_INET6) {
    if (ntohs(conn->client.lsa.sin6.sin6_port) != port) {
      /* Request is directed to a different port */
      return 0;
    }
  }
  else
#endif
  {
    if (ntohs(conn->client.lsa.sin.sin_port) != port) {
      /* Request is directed to a different port */
      return 0;
    }
  }

  if ((request_domain_len != server_domain_len)
    || (0 != memcmp(server_domain, hostbegin, server_domain_len))) {
    /* Request is directed to another server */
    return 0;
  }

  return hostend;
}


static int
getreq(struct mg_connection *conn, char *ebuf, size_t ebuf_len, int *err)
{
  const char *cl;

  if (ebuf_len > 0) {
    ebuf[0] = '\0';
  }
  *err = 0;

  reset_per_request_attributes(conn);

  if (!conn) {
    mg_snprintf(conn,
      NULL, /* No truncation check for ebuf */
      ebuf,
      ebuf_len,
      "%s",
      "Internal error");
    *err = 500;
    return 0;
  }
  /* Set the time the request was received. This value should be used for
  * timeouts. */
  clock_gettime(CLOCK_MONOTONIC, &(conn->req_time));

  conn->request_len =
    read_request(NULL, conn, conn->buf, conn->buf_size, &conn->data_len);
  /* assert(conn->request_len < 0 || conn->data_len >= conn->request_len);
  */
  if (conn->request_len >= 0 && conn->data_len < conn->request_len) {
    mg_snprintf(conn,
      NULL, /* No truncation check for ebuf */
      ebuf,
      ebuf_len,
      "%s",
      "Invalid request size");
    *err = 500;
    return 0;
  }

  if (conn->request_len == 0 && conn->data_len == conn->buf_size) {
    mg_snprintf(conn,
      NULL, /* No truncation check for ebuf */
      ebuf,
      ebuf_len,
      "%s",
      "Request Too Large");
    *err = 413;
    return 0;
  }
  else if (conn->request_len <= 0) {
    if (conn->data_len > 0) {
      mg_snprintf(conn,
        NULL, /* No truncation check for ebuf */
        ebuf,
        ebuf_len,
        "%s",
        "Client sent malformed request");
      *err = 400;
    }
    else {
      /* Server did not send anything -> just close the connection */
      conn->must_close = 1;
      mg_snprintf(conn,
        NULL, /* No truncation check for ebuf */
        ebuf,
        ebuf_len,
        "%s",
        "Client did not send a request");
      *err = 0;
    }
    return 0;
  }
  else if (parse_http_message(conn->buf,
    conn->buf_size,
    &conn->request_info) <= 0) {
    mg_snprintf(conn,
      NULL, /* No truncation check for ebuf */
      ebuf,
      ebuf_len,
      "%s",
      "Bad Request");
    *err = 400;
    return 0;
  }
  else {
    /* Message is a valid request or response */
    if ((cl = get_header(&conn->request_info, "Content-Length")) != NULL) {
      /* Request/response has content length set */
      char *endptr = NULL;
      conn->content_len = strtoll(cl, &endptr, 10);
      if (endptr == cl) {
        mg_snprintf(conn,
          NULL, /* No truncation check for ebuf */
          ebuf,
          ebuf_len,
          "%s",
          "Bad Request");
        *err = 411;
        return 0;
      }
      /* Publish the content length back to the request info. */
      conn->request_info.content_length = conn->content_len;
    }
    else if ((cl = get_header(&conn->request_info, "Transfer-Encoding"))
      != NULL
      && strcmp(cl, "chunked") == 0) {
      conn->is_chunked = 1;
    }
    else if (!mg_strcasecmp(conn->request_info.request_method, "POST")
      || !mg_strcasecmp(conn->request_info.request_method,
        "PUT")) {
      /* POST or PUT request without content length set */
      conn->content_len = -1;
    }
    else if (!mg_strncasecmp(conn->request_info.request_method,
      "HTTP/",
      5)) {
      /* Response without content length set */
      conn->content_len = -1;
    }
    else {
      /* Other request */
      conn->content_len = 0;
    }
  }
  return 1;
}

int
mg_get_response(struct mg_connection *conn,
  char *ebuf,
  size_t ebuf_len,
  int timeout)
{
  if (conn) {
    /* Implementation of API function for HTTP clients */
    int err, ret;
    struct mg_context *octx = conn->ctx;
    struct mg_context rctx = *(conn->ctx);
    char txt[32]; /* will not overflow */

    if (timeout >= 0) {
      mg_snprintf(conn, NULL, txt, sizeof(txt), "%i", timeout);
      rctx.config[REQUEST_TIMEOUT] = txt;
      set_sock_timeout(conn->client.sock, timeout);
    }
    else {
      rctx.config[REQUEST_TIMEOUT] = NULL;
    }

    conn->ctx = &rctx;
    ret = getreq(conn, ebuf, ebuf_len, &err);
    conn->ctx = octx;

    /* TODO: 1) uri is deprecated;
    *       2) here, ri.uri is the http response code */
    conn->request_info.uri = conn->request_info.request_uri;

    /* TODO (mid): Define proper return values - maybe return length?
    * For the first test use <0 for error and >0 for OK */
    return (ret == 0) ? -1 : +1;
  }
  return -1;
}

struct mg_connection *
  mg_download(const char *host,
    int port,
    int use_ssl,
    char *ebuf,
    size_t ebuf_len,
    const char *fmt,
    ...)
{
  struct mg_connection *conn;
  va_list ap;
  int i;
  int reqerr;

  va_start(ap, fmt);
  ebuf[0] = '\0';

  /* open a connection */
  conn = mg_connect_client(host, port, use_ssl, ebuf, ebuf_len);

  if (conn != NULL) {
    i = mg_vprintf(conn, fmt, ap);
    if (i <= 0) {
      mg_snprintf(conn,
        NULL, /* No truncation check for ebuf */
        ebuf,
        ebuf_len,
        "%s",
        "Error sending request");
    }
    else {
      getreq(conn, ebuf, ebuf_len, &reqerr);

      /* TODO: 1) uri is deprecated;
      *       2) here, ri.uri is the http response code */
      conn->request_info.uri = conn->request_info.request_uri;
    }
  }

  /* if an error occured, close the connection */
  if (ebuf[0] != '\0' && conn != NULL) {
    mg_close_connection(conn);
    conn = NULL;
  }

  va_end(ap);
  return conn;
}

struct websocket_client_thread_data {
  struct mg_connection *conn;
  mg_websocket_data_handler data_handler;
  mg_websocket_close_handler close_handler;
  void *callback_data;
};


#if defined(USE_WEBSOCKET)
#ifdef _WIN32
static unsigned __stdcall websocket_client_thread(void *data)
#else
static void *
websocket_client_thread(void *data)
#endif
{
  struct websocket_client_thread_data *cdata =
    (struct websocket_client_thread_data *)data;
  read_websocket(cdata->conn, cdata->data_handler, cdata->callback_data);

  DEBUG_TRACE("%s", "Websocket client thread exited\n");

  if (cdata->close_handler != NULL) {
    cdata->close_handler(cdata->conn, cdata->callback_data);
  }

  mg_free((void *)cdata);

#ifdef _WIN32
  return 0;
#else
  return NULL;
#endif
}
#endif

struct mg_connection *
  mg_connect_websocket_client(const char *host,
    int port,
    int use_ssl,
    char *error_buffer,
    size_t error_buffer_size,
    const char *path,
    const char *origin,
    mg_websocket_data_handler data_func,
    mg_websocket_close_handler close_func,
    void *user_data)
{
  struct mg_connection *conn = NULL;

#if defined(USE_WEBSOCKET)
  struct mg_context *newctx = NULL;
  struct websocket_client_thread_data *thread_data;
  static const char *magic = "x3JJHMbDL1EzLkh9GBhXDw==";
  static const char *handshake_req;

  if (origin != NULL) {
    handshake_req = "GET %s HTTP/1.1\r\n"
      "Host: %s\r\n"
      "Upgrade: websocket\r\n"
      "Connection: Upgrade\r\n"
      "Sec-WebSocket-Key: %s\r\n"
      "Sec-WebSocket-Version: 13\r\n"
      "Origin: %s\r\n"
      "\r\n";
  }
  else {
    handshake_req = "GET %s HTTP/1.1\r\n"
      "Host: %s\r\n"
      "Upgrade: websocket\r\n"
      "Connection: Upgrade\r\n"
      "Sec-WebSocket-Key: %s\r\n"
      "Sec-WebSocket-Version: 13\r\n"
      "\r\n";
  }

  /* Establish the client connection and request upgrade */
  conn = mg_download(host,
    port,
    use_ssl,
    error_buffer,
    error_buffer_size,
    handshake_req,
    path,
    host,
    magic,
    origin);

  /* Connection object will be null if something goes wrong */
  if (conn == NULL || (strcmp(conn->request_info.request_uri, "101") != 0)) {
    if (!*error_buffer) {
      /* if there is a connection, but it did not return 101,
      * error_buffer is not yet set */
      mg_snprintf(conn,
        NULL, /* No truncation check for ebuf */
        error_buffer,
        error_buffer_size,
        "Unexpected server reply");
    }
    DEBUG_TRACE("Websocket client connect error: %s\r\n", error_buffer);
    if (conn != NULL) {
      mg_free(conn);
      conn = NULL;
    }
    return conn;
  }

  /* For client connections, mg_context is fake. Since we need to set a
  * callback function, we need to create a copy and modify it. */
  newctx = (struct mg_context *)mg_malloc(sizeof(struct mg_context));
  memcpy(newctx, conn->ctx, sizeof(struct mg_context));
  newctx->user_data = user_data;
  newctx->context_type = 2;       /* client context type */
  newctx->cfg_worker_threads = 1; /* one worker thread will be created */
  newctx->workerthreadids =
    (pthread_t *)mg_calloc(newctx->cfg_worker_threads, sizeof(pthread_t));
  conn->ctx = newctx;
  thread_data = (struct websocket_client_thread_data *)
    mg_calloc(sizeof(struct websocket_client_thread_data), 1);
  thread_data->conn = conn;
  thread_data->data_handler = data_func;
  thread_data->close_handler = close_func;
  thread_data->callback_data = NULL;

  /* Start a thread to read the websocket client connection
  * This thread will automatically stop when mg_disconnect is
  * called on the client connection */
  if (mg_start_thread_with_id(websocket_client_thread,
    (void *)thread_data,
    newctx->workerthreadids) != 0) {
    mg_free((void *)thread_data);
    mg_free((void *)newctx->workerthreadids);
    mg_free((void *)newctx);
    mg_free((void *)conn);
    conn = NULL;
    DEBUG_TRACE("%s",
      "Websocket client connect thread could not be started\r\n");
  }
#else
  /* Appease "unused parameter" warnings */
  (void)host;
  (void)port;
  (void)use_ssl;
  (void)error_buffer;
  (void)error_buffer_size;
  (void)path;
  (void)origin;
  (void)user_data;
  (void)data_func;
  (void)close_func;
#endif

  return conn;
}


static void
process_new_connection(struct mg_connection *conn)
{
  if (conn && conn->ctx) {
    struct mg_request_info *ri = &conn->request_info;
    int keep_alive_enabled, keep_alive, discard_len;
    char ebuf[100];
    const char *hostend;
    int reqerr, uri_type;

    keep_alive_enabled =
      !strcmp(conn->ctx->config[ENABLE_KEEP_ALIVE], "yes");

    /* Important: on new connection, reset the receiving buffer. Credit
    * goes to crule42. */
    conn->data_len = 0;
    do {
      if (!getreq(conn, ebuf, sizeof(ebuf), &reqerr)) {
        /* The request sent by the client could not be understood by
        * the server, or it was incomplete or a timeout. Send an
        * error message and close the connection. */
        if (reqerr > 0) {
          /*assert(ebuf[0] != '\0');*/
          send_http_error(conn, reqerr, "%s", ebuf);
        }
      }
      else if (strcmp(ri->http_version, "1.0")
        && strcmp(ri->http_version, "1.1")) {
        mg_snprintf(conn,
          NULL, /* No truncation check for ebuf */
          ebuf,
          sizeof(ebuf),
          "Bad HTTP version: [%s]",
          ri->http_version);
        send_http_error(conn, 505, "%s", ebuf);
      }

      if (ebuf[0] == '\0') {
        uri_type = get_uri_type(conn->request_info.request_uri);
        switch (uri_type) {
        case 1:
          /* Asterisk */
          conn->request_info.local_uri = NULL;
          break;
        case 2:
          /* relative uri */
          conn->request_info.local_uri =
            conn->request_info.request_uri;
          break;
        case 3:
        case 4:
          /* absolute uri (with/without port) */
          hostend = get_rel_url_at_current_server(
            conn->request_info.request_uri, conn);
          if (hostend) {
            conn->request_info.local_uri = hostend;
          }
          else {
            conn->request_info.local_uri = NULL;
          }
          break;
        default:
          mg_snprintf(conn,
            NULL, /* No truncation check for ebuf */
            ebuf,
            sizeof(ebuf),
            "Invalid URI: [%s]",
            ri->request_uri);
          send_http_error(conn, 400, "%s", ebuf);
          break;
        }

        /* TODO: cleanup uri, local_uri and request_uri */
        conn->request_info.uri = conn->request_info.local_uri;
      }

      if (ebuf[0] == '\0') {
        if (conn->request_info.local_uri) {
          /* handle request to local server */
          handle_request(conn);
          if (conn->ctx->callbacks.end_request != NULL) {
            conn->ctx->callbacks.end_request(conn,
              conn->status_code);
          }
          log_access(conn);
        }
        else {
          /* TODO: handle non-local request (PROXY) */
          conn->must_close = 1;
        }
      }
      else {
        conn->must_close = 1;
      }

      if (ri->remote_user != NULL) {
        mg_free((void *)ri->remote_user);
        /* Important! When having connections with and without auth
        * would cause double free and then crash */
        ri->remote_user = NULL;
      }

      /* NOTE(lsm): order is important here. should_keep_alive() call
      * is
      * using parsed request, which will be invalid after memmove's
      * below.
      * Therefore, memorize should_keep_alive() result now for later
      * use
      * in loop exit condition. */
      keep_alive = conn->ctx->stop_flag == 0 && keep_alive_enabled
        && conn->content_len >= 0 && should_keep_alive(conn);

      /* Discard all buffered data for this request */
      discard_len = conn->content_len >= 0 && conn->request_len > 0
        && conn->request_len + conn->content_len
        < (int64_t)conn->data_len
        ? (int)(conn->request_len + conn->content_len)
        : conn->data_len;
      /*assert(discard_len >= 0);*/
      if (discard_len < 0)
        break;
      conn->data_len -= discard_len;
      if (conn->data_len > 0) {
        memmove(conn->buf,
          conn->buf + discard_len,
          (size_t)conn->data_len);
      }

      /* assert(conn->data_len >= 0); */
      /* assert(conn->data_len <= conn->buf_size); */

      if ((conn->data_len < 0) || (conn->data_len > conn->buf_size)) {
        break;
      }

    } while (keep_alive);
  }
}


/* Worker threads take accepted socket from the queue */
static int
consume_socket(struct mg_context *ctx, struct socket *sp)
{
#define QUEUE_SIZE(ctx) ((int)(ARRAY_SIZE(ctx->queue)))
  if (!ctx) {
    return 0;
  }

  (void)pthread_mutex_lock(&ctx->thread_mutex);
  DEBUG_TRACE("%s", "going idle");

  /* If the queue is empty, wait. We're idle at this point. */
  while (ctx->sq_head == ctx->sq_tail && ctx->stop_flag == 0) {
    pthread_cond_wait(&ctx->sq_full, &ctx->thread_mutex);
  }

  /* If we're stopping, sq_head may be equal to sq_tail. */
  if (ctx->sq_head > ctx->sq_tail) {
    /* Copy socket from the queue and increment tail */
    *sp = ctx->queue[ctx->sq_tail % QUEUE_SIZE(ctx)];
    ctx->sq_tail++;

    DEBUG_TRACE("grabbed socket %d, going busy", sp ? sp->sock : -1);

    /* Wrap pointers if needed */
    while (ctx->sq_tail > QUEUE_SIZE(ctx)) {
      ctx->sq_tail -= QUEUE_SIZE(ctx);
      ctx->sq_head -= QUEUE_SIZE(ctx);
    }
  }

  (void)pthread_cond_signal(&ctx->sq_empty);
  (void)pthread_mutex_unlock(&ctx->thread_mutex);

  return !ctx->stop_flag;
#undef QUEUE_SIZE
}


static void *
worker_thread_run(void *thread_func_param)
{
  struct mg_context *ctx = (struct mg_context *)thread_func_param;
  struct mg_connection *conn;
  struct mg_workerTLS tls;
#if defined(MG_LEGACY_INTERFACE)
  uint32_t addr;
#endif

  mg_set_thread_name("worker");

  tls.is_master = 0;
  tls.thread_idx = (unsigned)mg_atomic_inc(&thread_idx_max);
#if defined(_WIN32) && !defined(__SYMBIAN32__)
  tls.pthread_cond_helper_mutex = CreateEvent(NULL, FALSE, FALSE, NULL);
#endif

  conn =
    (struct mg_connection *)mg_calloc(1, sizeof(*conn) + MAX_REQUEST_SIZE);
  if (conn == NULL) {
    mg_cry(fc(ctx), "%s", "Cannot create new connection struct, OOM");
  }
  else {
    pthread_setspecific(sTlsKey, &tls);
    conn->buf_size = MAX_REQUEST_SIZE;
    conn->buf = (char *)(conn + 1);
    conn->ctx = ctx;
    conn->request_info.user_data = ctx->user_data;
    /* Allocate a mutex for this connection to allow communication both
    * within the request handler and from elsewhere in the application
    */
    (void)pthread_mutex_init(&conn->mutex, &pthread_mutex_attr);

    /* Call consume_socket() even when ctx->stop_flag > 0, to let it
    * signal sq_empty condvar to wake up the master waiting in
    * produce_socket() */
    while (consume_socket(ctx, &conn->client)) {
      conn->conn_birth_time = time(NULL);

      /* Fill in IP, port info early so even if SSL setup below fails,
      * error handler would have the corresponding info.
      * Thanks to Johannes Winkelmann for the patch.
      */
#if defined(USE_IPV6)
      if (conn->client.rsa.sa.sa_family == AF_INET6) {
        conn->request_info.remote_port =
          ntohs(conn->client.rsa.sin6.sin6_port);
      }
      else
#endif
      {
        conn->request_info.remote_port =
          ntohs(conn->client.rsa.sin.sin_port);
      }

      sockaddr_to_string(conn->request_info.remote_addr,
        sizeof(conn->request_info.remote_addr),
        &conn->client.rsa);

#if defined(MG_LEGACY_INTERFACE)
      /* This legacy interface only works for the IPv4 case */
      addr = ntohl(conn->client.rsa.sin.sin_addr.s_addr);
      memcpy(&conn->request_info.remote_ip, &addr, 4);
#endif

      conn->request_info.is_ssl = conn->client.is_ssl;

      if (!conn->client.is_ssl
#ifndef NO_SSL
        || sslize(conn, conn->ctx->ssl_ctx, SSL_accept)
#endif
        ) {


        process_new_connection(conn);
      }

      close_connection(conn);
    }
  }

  /* Signal master that we're done with connection and exiting */
  (void)pthread_mutex_lock(&ctx->thread_mutex);
  ctx->running_worker_threads--;
  (void)pthread_cond_signal(&ctx->thread_cond);
  /* assert(ctx->running_worker_threads >= 0); */
  (void)pthread_mutex_unlock(&ctx->thread_mutex);

  pthread_setspecific(sTlsKey, NULL);
#if defined(_WIN32) && !defined(__SYMBIAN32__)
  CloseHandle(tls.pthread_cond_helper_mutex);
#endif
  pthread_mutex_destroy(&conn->mutex);
  mg_free(conn);

  DEBUG_TRACE("%s", "exiting");
  return NULL;
}


/* Threads have different return types on Windows and Unix. */
#ifdef _WIN32
static unsigned __stdcall mg_worker_thread(void *thread_func_param)
{
  worker_thread_run(thread_func_param);
  return 0;
}
#else
static void *
mg_worker_thread(void *thread_func_param)
{
  worker_thread_run(thread_func_param);
  return NULL;
}
#endif /* _WIN32 */


/* Master thread adds accepted socket to a queue */
static void
produce_socket(struct mg_context *ctx, const struct socket *sp)
{
#define QUEUE_SIZE(ctx) ((int)(ARRAY_SIZE(ctx->queue)))
  if (!ctx) {
    return;
  }
  (void)pthread_mutex_lock(&ctx->thread_mutex);

  /* If the queue is full, wait */
  while (ctx->stop_flag == 0
    && ctx->sq_head - ctx->sq_tail >= QUEUE_SIZE(ctx)) {
    (void)pthread_cond_wait(&ctx->sq_empty, &ctx->thread_mutex);
  }

  if (ctx->sq_head - ctx->sq_tail < QUEUE_SIZE(ctx)) {
    /* Copy socket to the queue and increment head */
    ctx->queue[ctx->sq_head % QUEUE_SIZE(ctx)] = *sp;
    ctx->sq_head++;
    DEBUG_TRACE("queued socket %d", sp ? sp->sock : -1);
  }

  (void)pthread_cond_signal(&ctx->sq_full);
  (void)pthread_mutex_unlock(&ctx->thread_mutex);
#undef QUEUE_SIZE
}


static void
accept_new_connection(const struct socket *listener, struct mg_context *ctx)
{
  struct socket so;
  char src_addr[IP_ADDR_STR_LEN];
  socklen_t len = sizeof(so.rsa);
  int on = 1;
  int timeout;

  if (!listener) {
    return;
  }

  if ((so.sock = accept(listener->sock, &so.rsa.sa, &len))
    == INVALID_SOCKET) {
  }
  else if (!check_acl(ctx, ntohl(*(uint32_t *)&so.rsa.sin.sin_addr))) {
    sockaddr_to_string(src_addr, sizeof(src_addr), &so.rsa);
    mg_cry(fc(ctx), "%s: %s is not allowed to connect", __func__, src_addr);
    closesocket(so.sock);
    so.sock = INVALID_SOCKET;
  }
  else {
    /* Put so socket structure into the queue */
    DEBUG_TRACE("Accepted socket %d", (int)so.sock);
    set_close_on_exec(so.sock, fc(ctx));
    so.is_ssl = listener->is_ssl;
    so.ssl_redir = listener->ssl_redir;
    if (getsockname(so.sock, &so.lsa.sa, &len) != 0) {
      mg_cry(fc(ctx),
        "%s: getsockname() failed: %s",
        __func__,
        strerror(ERRNO));
    }

    /* Set TCP keep-alive. This is needed because if HTTP-level
    * keep-alive
    * is enabled, and client resets the connection, server won't get
    * TCP FIN or RST and will keep the connection open forever. With
    * TCP keep-alive, next keep-alive handshake will figure out that
    * the client is down and will close the server end.
    * Thanks to Igor Klopov who suggested the patch. */
    if (setsockopt(so.sock,
      SOL_SOCKET,
      SO_KEEPALIVE,
      (SOCK_OPT_TYPE)&on,
      sizeof(on)) != 0) {
      mg_cry(fc(ctx),
        "%s: setsockopt(SOL_SOCKET SO_KEEPALIVE) failed: %s",
        __func__,
        strerror(ERRNO));
    }


    /* Disable TCP Nagle's algorithm.  Normally TCP packets are coalesced
    * to effectively fill up the underlying IP packet payload and reduce
    * the overhead of sending lots of small buffers. However this hurts
    * the server's throughput (ie. operations per second) when HTTP 1.1
    * persistent connections are used and the responses are relatively
    * small (eg. less than 1400 bytes).
    */
    if ((ctx != NULL) && (ctx->config[CONFIG_TCP_NODELAY] != NULL)
      && (!strcmp(ctx->config[CONFIG_TCP_NODELAY], "1"))) {
      if (set_tcp_nodelay(so.sock, 1) != 0) {
        mg_cry(fc(ctx),
          "%s: setsockopt(IPPROTO_TCP TCP_NODELAY) failed: %s",
          __func__,
          strerror(ERRNO));
      }
    }

    if (ctx && ctx->config[REQUEST_TIMEOUT]) {
      timeout = atoi(ctx->config[REQUEST_TIMEOUT]);
    }
    else {
      timeout = -1;
    }

    /* Set socket timeout to the given value, but not more than a
    * a certain limit (SOCKET_TIMEOUT_QUANTUM, default 10 seconds),
    * so the server can exit after that time if requested. */
    if ((timeout > 0) && (timeout < SOCKET_TIMEOUT_QUANTUM)) {
      set_sock_timeout(so.sock, timeout);
    }
    else {
      set_sock_timeout(so.sock, SOCKET_TIMEOUT_QUANTUM);
    }

    produce_socket(ctx, &so);
  }
}


static void
master_thread_run(void *thread_func_param)
{
  struct mg_context *ctx = (struct mg_context *)thread_func_param;
  struct mg_workerTLS tls;
  struct pollfd *pfd;
  unsigned int i;
  unsigned int workerthreadcount;

  if (!ctx) {
    return;
  }

  mg_set_thread_name("master");

  /* Increase priority of the master thread */
#if defined(_WIN32)
  SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_ABOVE_NORMAL);
#elif defined(USE_MASTER_THREAD_PRIORITY)
  int min_prio = sched_get_priority_min(SCHED_RR);
  int max_prio = sched_get_priority_max(SCHED_RR);
  if ((min_prio >= 0) && (max_prio >= 0)
    && ((USE_MASTER_THREAD_PRIORITY) <= max_prio)
    && ((USE_MASTER_THREAD_PRIORITY) >= min_prio)) {
    struct sched_param sched_param = { 0 };
    sched_param.sched_priority = (USE_MASTER_THREAD_PRIORITY);
    pthread_setschedparam(pthread_self(), SCHED_RR, &sched_param);
  }
#endif

  /* Initialize thread local storage */
#if defined(_WIN32) && !defined(__SYMBIAN32__)
  tls.pthread_cond_helper_mutex = CreateEvent(NULL, FALSE, FALSE, NULL);
#endif
  tls.is_master = 1;
  pthread_setspecific(sTlsKey, &tls);

  /* Server starts *now* */
  ctx->start_time = time(NULL);

  /* Allocate memory for the listening sockets, and start the server */
  pfd =
    (struct pollfd *)mg_calloc(ctx->num_listening_sockets, sizeof(pfd[0]));
  while (pfd != NULL && ctx->stop_flag == 0) {
    for (i = 0; i < ctx->num_listening_sockets; i++) {
      pfd[i].fd = ctx->listening_sockets[i].sock;
      pfd[i].events = POLLIN;
    }

    if (poll(pfd, ctx->num_listening_sockets, 200) > 0) {
      for (i = 0; i < ctx->num_listening_sockets; i++) {
        /* NOTE(lsm): on QNX, poll() returns POLLRDNORM after the
        * successful poll, and POLLIN is defined as
        * (POLLRDNORM | POLLRDBAND)
        * Therefore, we're checking pfd[i].revents & POLLIN, not
        * pfd[i].revents == POLLIN. */
        if (ctx->stop_flag == 0 && (pfd[i].revents & POLLIN)) {
          accept_new_connection(&ctx->listening_sockets[i], ctx);
        }
      }
    }
  }
  mg_free(pfd);
  DEBUG_TRACE("%s", "stopping workers");

  /* Stop signal received: somebody called mg_stop. Quit. */
  close_all_listening_sockets(ctx);

  /* Wakeup workers that are waiting for connections to handle. */
  pthread_cond_broadcast(&ctx->sq_full);

  /* Wait until all threads finish */
  (void)pthread_mutex_lock(&ctx->thread_mutex);
  while (ctx->running_worker_threads > 0) {
    (void)pthread_cond_wait(&ctx->thread_cond, &ctx->thread_mutex);
  }
  (void)pthread_mutex_unlock(&ctx->thread_mutex);

  /* Join all worker threads to avoid leaking threads. */
  workerthreadcount = ctx->cfg_worker_threads;
  for (i = 0; i < workerthreadcount; i++) {
    if (ctx->workerthreadids[i] != 0) {
      mg_join_thread(ctx->workerthreadids[i]);
    }
  }

#if !defined(NO_SSL)
  if (ctx->ssl_ctx != NULL) {
    uninitialize_ssl(ctx);
  }
#endif
  DEBUG_TRACE("%s", "exiting");

#if defined(_WIN32) && !defined(__SYMBIAN32__)
  CloseHandle(tls.pthread_cond_helper_mutex);
#endif
  pthread_setspecific(sTlsKey, NULL);

  /* Signal mg_stop() that we're done.
  * WARNING: This must be the very last thing this
  * thread does, as ctx becomes invalid after this line. */
  ctx->stop_flag = 2;
}


/* Threads have different return types on Windows and Unix. */
#ifdef _WIN32
static unsigned __stdcall master_thread(void *thread_func_param)
{
  master_thread_run(thread_func_param);
  return 0;
}
#else
static void *
master_thread(void *thread_func_param)
{
  master_thread_run(thread_func_param);
  return NULL;
}
#endif /* _WIN32 */


static void
free_context(struct mg_context *ctx)
{
  int i;
  struct mg_handler_info *tmp_rh;

  if (ctx == NULL) {
    return;
  }

  if (ctx->callbacks.exit_context) {
    ctx->callbacks.exit_context(ctx);
  }

  /* All threads exited, no sync is needed. Destroy thread mutex and
  * condvars
  */
  (void)pthread_mutex_destroy(&ctx->thread_mutex);
  (void)pthread_cond_destroy(&ctx->thread_cond);
  (void)pthread_cond_destroy(&ctx->sq_empty);
  (void)pthread_cond_destroy(&ctx->sq_full);

  /* Destroy other context global data structures mutex */
  (void)pthread_mutex_destroy(&ctx->nonce_mutex);

#if defined(USE_TIMERS)
  timers_exit(ctx);
#endif

  /* Deallocate config parameters */
  for (i = 0; i < NUM_OPTIONS; i++) {
    if (ctx->config[i] != NULL) {
#if defined(_MSC_VER)
#pragma warning(suppress : 6001)
#endif
      mg_free(ctx->config[i]);
    }
  }

  /* Deallocate request handlers */
  while (ctx->handlers) {
    tmp_rh = ctx->handlers;
    ctx->handlers = tmp_rh->next;
    mg_free(tmp_rh->uri);
    mg_free(tmp_rh);
  }

#ifndef NO_SSL
  /* Deallocate SSL context */
  if (ctx->ssl_ctx != NULL) {
    SSL_CTX_free(ctx->ssl_ctx);
  }
#endif /* !NO_SSL */

  /* Deallocate worker thread ID array */
  if (ctx->workerthreadids != NULL) {
    mg_free(ctx->workerthreadids);
  }

  /* Deallocate the tls variable */
  if (mg_atomic_dec(&sTlsInit) == 0) {
#if defined(_WIN32) && !defined(__SYMBIAN32__)
    DeleteCriticalSection(&global_log_file_lock);
#endif /* _WIN32 && !__SYMBIAN32__ */
#if !defined(_WIN32)
    pthread_mutexattr_destroy(&pthread_mutex_attr);
#endif

    pthread_key_delete(sTlsKey);
  }

  /* deallocate system name string */
  mg_free(ctx->systemName);

  /* Deallocate context itself */
  mg_free(ctx);
}


void
mg_stop(struct mg_context *ctx)
{
  pthread_t mt;
  if (!ctx) {
    return;
  }

  /* We don't use a lock here. Calling mg_stop with the same ctx from
  * two threads is not allowed. */
  mt = ctx->masterthreadid;
  if (mt == 0) {
    return;
  }

  ctx->masterthreadid = 0;
  ctx->stop_flag = 1;

  /* Wait until mg_fini() stops */
  while (ctx->stop_flag != 2) {
    (void)mg_sleep(10);
  }

  mg_join_thread(mt);
  free_context(ctx);

#if defined(_WIN32) && !defined(__SYMBIAN32__)
  (void)WSACleanup();
#endif /* _WIN32 && !__SYMBIAN32__ */
}


static void
get_system_name(char **sysName)
{
#if defined(_WIN32)
#if !defined(__SYMBIAN32__)
  char name[128];
  DWORD dwVersion = 0;
  DWORD dwMajorVersion = 0;
  DWORD dwMinorVersion = 0;
  DWORD dwBuild = 0;

#ifdef _MSC_VER
#pragma warning(push)
  // GetVersion was declared deprecated
#pragma warning(disable : 4996)
#endif
  dwVersion = GetVersion();
#ifdef _MSC_VER
#pragma warning(pop)
#endif

  dwMajorVersion = (DWORD)(LOBYTE(LOWORD(dwVersion)));
  dwMinorVersion = (DWORD)(HIBYTE(LOWORD(dwVersion)));
  dwBuild = ((dwVersion < 0x80000000) ? (DWORD)(HIWORD(dwVersion)) : 0);
  (void)dwBuild;

  sprintf(name,
    "Windows %u.%u",
    (unsigned)dwMajorVersion,
    (unsigned)dwMinorVersion);
  *sysName = mg_strdup(name);
#else
  *sysName = mg_strdup("Symbian");
#endif
#else
  struct utsname name;
  memset(&name, 0, sizeof(name));
  uname(&name);
  *sysName = mg_strdup(name.sysname);
#endif
}

struct mg_context *
  mg_start(const struct mg_callbacks *callbacks,
    void *user_data,
    const char **options)
{
  struct mg_context *ctx;
  const char *name, *value, *default_value;
  int idx, ok, workerthreadcount;
  unsigned int i;
  void(*exit_callback)(const struct mg_context *ctx) = 0;

  struct mg_workerTLS tls;

#if defined(_WIN32) && !defined(__SYMBIAN32__)
  WSADATA data;
  WSAStartup(MAKEWORD(2, 2), &data);
#endif /* _WIN32 && !__SYMBIAN32__ */

  /* Allocate context and initialize reasonable general case defaults. */
  if ((ctx = (struct mg_context *)mg_calloc(1, sizeof(*ctx))) == NULL) {
    return NULL;
  }

  /* Random number generator will initialize at the first call */
  ctx->auth_nonce_mask =
    (uint64_t)get_random() ^ (uint64_t)(ptrdiff_t)(options);

  if (mg_atomic_inc(&sTlsInit) == 1) {

#if defined(_WIN32) && !defined(__SYMBIAN32__)
    InitializeCriticalSection(&global_log_file_lock);
#endif /* _WIN32 && !__SYMBIAN32__ */
#if !defined(_WIN32)
    pthread_mutexattr_init(&pthread_mutex_attr);
    pthread_mutexattr_settype(&pthread_mutex_attr, PTHREAD_MUTEX_RECURSIVE);
#endif

    if (0 != pthread_key_create(&sTlsKey, tls_dtor)) {
      /* Fatal error - abort start. However, this situation should
      * never
      * occur in practice. */
      mg_atomic_dec(&sTlsInit);
      mg_cry(fc(ctx), "Cannot initialize thread local storage");
      mg_free(ctx);
      return NULL;
    }
  }
  else {
    /* TODO (low): istead of sleeping, check if sTlsKey is already
    * initialized. */
    mg_sleep(1);
  }

  tls.is_master = -1;
  tls.thread_idx = (unsigned)mg_atomic_inc(&thread_idx_max);
#if defined(_WIN32) && !defined(__SYMBIAN32__)
  tls.pthread_cond_helper_mutex = NULL;
#endif
  pthread_setspecific(sTlsKey, &tls);

  ok = 0 == pthread_mutex_init(&ctx->thread_mutex, &pthread_mutex_attr);
  ok &= 0 == pthread_cond_init(&ctx->thread_cond, NULL);
  ok &= 0 == pthread_cond_init(&ctx->sq_empty, NULL);
  ok &= 0 == pthread_cond_init(&ctx->sq_full, NULL);
  ok &= 0 == pthread_mutex_init(&ctx->nonce_mutex, &pthread_mutex_attr);
  if (!ok) {
    /* Fatal error - abort start. However, this situation should never
    * occur in practice. */
    mg_cry(fc(ctx), "Cannot initialize thread synchronization objects");
    mg_free(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }

  if (callbacks) {
    ctx->callbacks = *callbacks;
    exit_callback = callbacks->exit_context;
    ctx->callbacks.exit_context = 0;
  }
  ctx->user_data = user_data;
  ctx->handlers = NULL;

#if defined(USE_LUA) && defined(USE_WEBSOCKET)
  ctx->shared_lua_websockets = 0;
#endif

  while (options && (name = *options++) != NULL) {
    if ((idx = get_option_index(name)) == -1) {
      mg_cry(fc(ctx), "Invalid option: %s", name);
      free_context(ctx);
      pthread_setspecific(sTlsKey, NULL);
      return NULL;
    }
    else if ((value = *options++) == NULL) {
      mg_cry(fc(ctx), "%s: option value cannot be NULL", name);
      free_context(ctx);
      pthread_setspecific(sTlsKey, NULL);
      return NULL;
    }
    if (ctx->config[idx] != NULL) {
      mg_cry(fc(ctx), "warning: %s: duplicate option", name);
      mg_free(ctx->config[idx]);
    }
    ctx->config[idx] = mg_strdup(value);
    DEBUG_TRACE("[%s] -> [%s]", name, value);
  }

  /* Set default value if needed */
  for (i = 0; config_options[i].name != NULL; i++) {
    default_value = config_options[i].default_value;
    if (ctx->config[i] == NULL && default_value != NULL) {
      ctx->config[i] = mg_strdup(default_value);
    }
  }

#if defined(NO_FILES)
  if (ctx->config[DOCUMENT_ROOT] != NULL) {
    mg_cry(fc(ctx), "%s", "Document root must not be set");
    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }
#endif

  get_system_name(&ctx->systemName);

  /* NOTE(lsm): order is important here. SSL certificates must
  * be initialized before listening ports. UID must be set last. */
  if (!set_gpass_option(ctx) ||
#if !defined(NO_SSL)
    !set_ssl_option(ctx) ||
#endif
    !set_ports_option(ctx) ||
#if !defined(_WIN32)
    !set_uid_option(ctx) ||
#endif
    !set_acl_option(ctx)) {
    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }

#if !defined(_WIN32) && !defined(__SYMBIAN32__)
  /* Ignore SIGPIPE signal, so if browser cancels the request, it
  * won't kill the whole process. */
  (void)signal(SIGPIPE, SIG_IGN);
#endif /* !_WIN32 && !__SYMBIAN32__ */

  workerthreadcount = atoi(ctx->config[NUM_THREADS]);

  if (workerthreadcount > MAX_WORKER_THREADS) {
    mg_cry(fc(ctx), "Too many worker threads");
    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }

  if (workerthreadcount > 0) {
    ctx->cfg_worker_threads = ((unsigned int)(workerthreadcount));
    ctx->workerthreadids =
      (pthread_t *)mg_calloc(ctx->cfg_worker_threads, sizeof(pthread_t));
    if (ctx->workerthreadids == NULL) {
      mg_cry(fc(ctx), "Not enough memory for worker thread ID array");
      free_context(ctx);
      pthread_setspecific(sTlsKey, NULL);
      return NULL;
    }
  }

#if defined(USE_TIMERS)
  if (timers_init(ctx) != 0) {
    mg_cry(fc(ctx), "Error creating timers");
    free_context(ctx);
    pthread_setspecific(sTlsKey, NULL);
    return NULL;
  }
#endif

  /* Context has been created - init user libraries */
  if (ctx->callbacks.init_context) {
    ctx->callbacks.init_context(ctx);
  }
  ctx->callbacks.exit_context = exit_callback;
  ctx->context_type = 1; /* server context */

                         /* Start master (listening) thread */
  mg_start_thread_with_id(master_thread, ctx, &ctx->masterthreadid);

  /* Start worker threads */
  for (i = 0; i < ctx->cfg_worker_threads; i++) {
    (void)pthread_mutex_lock(&ctx->thread_mutex);
    ctx->running_worker_threads++;
    (void)pthread_mutex_unlock(&ctx->thread_mutex);
    if (mg_start_thread_with_id(mg_worker_thread,
      ctx,
      &ctx->workerthreadids[i]) != 0) {
      (void)pthread_mutex_lock(&ctx->thread_mutex);
      ctx->running_worker_threads--;
      (void)pthread_mutex_unlock(&ctx->thread_mutex);
      if (i > 0) {
        mg_cry(fc(ctx),
          "Cannot start worker thread %i: error %ld",
          i + 1,
          (long)ERRNO);
      }
      else {
        mg_cry(fc(ctx),
          "Cannot create threads: error %ld",
          (long)ERRNO);
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
      }
      break;
    }
  }

  pthread_setspecific(sTlsKey, NULL);
  return ctx;
}


/* Feature check API function */
unsigned
mg_check_feature(unsigned feature)
{
  static const unsigned feature_set = 0
    /* Set bits for available features according to API documentation.
    * This bit mask is created at compile time, according to the active
    * preprocessor defines. It is a single const value at runtime. */
#if !defined(NO_FILES)
    | 1
#endif
#if !defined(NO_SSL)
    | 2
#endif
#if !defined(NO_CGI)
    | 4
#endif
#if defined(USE_IPV6)
    | 8
#endif
#if defined(USE_WEBSOCKET)
    | 16
#endif
#if defined(USE_LUA)
    | 32
#endif
#if defined(USE_DUKTAPE)
    | 64
#endif

    /* Set some extra bits not defined in the API documentation.
    * These bits may change without further notice. */
#if defined(MG_LEGACY_INTERFACE)
    | 128
#endif
#if defined(MEMORY_DEBUGGING)
    | 256
#endif
#if defined(USE_TIMERS)
    | 512
#endif
#if !defined(NO_NONCE_CHECK)
    | 1024
#endif
#if !defined(NO_POPEN)
    | 2048
#endif
    ;
  return (feature & feature_set);
}