main.cpp

/* Copyright 2012-present Facebook, Inc.
 * Licensed under the Apache License, Version 2.0 */
#include "watchman.h"
#include "ChildProcess.h"
#include "LogConfig.h"
#include "Logging.h"
#include "ThreadPool.h"
#ifdef _WIN32
#include <Lmcons.h>
#include <Shlobj.h>
#endif
#ifndef _WIN32
#include <poll.h>
#endif
#include <folly/Exception.h>
#include <folly/ScopeGuard.h>
#include <folly/Singleton.h>
#include <folly/SocketAddress.h>
#include <folly/String.h>
#include <folly/net/NetworkSocket.h>

#ifdef _WIN32
#include <deelevate.h>
#endif

using watchman::ChildProcess;
using watchman::FileDescriptor;
using Options = ChildProcess::Options;
using namespace watchman;

static int show_help = 0;
static int show_version = 0;
static int enable_tcp = 0;
static std::string tcp_host;
static enum w_pdu_type server_pdu = is_bser;
static enum w_pdu_type output_pdu = is_json_pretty;
static uint32_t server_capabilities = 0;
static uint32_t output_capabilities = 0;
static std::string server_encoding;
static std::string output_encoding;
static std::string test_state_dir;
static std::string pid_file;
static char** daemon_argv = NULL;
static int persistent = 0;
static int foreground = 0;
static int no_pretty = 0;
static int no_spawn = 0;
static int no_local = 0;
static int no_site_spawner = 0;
#ifndef _WIN32
static int inetd_style = 0;
#endif
static struct sockaddr_un un;
static int json_input_arg = 0;

#ifdef __APPLE__
#include <mach-o/dyld.h>
#endif

static std::string compute_user_name(void);
static void compute_file_name(
    std::string& str,
    const std::string& user,
    const char* suffix,
    const char* what);

static bool lock_pidfile(void) {
  // We defer computing this path until we're in the server context because
  // eager evaluation can trigger integration test failures unless all clients
  // are aware of both the pidfile and the sockpath being used in the tests.
  compute_file_name(pid_file, compute_user_name(), "pid", "pidfile");

#if !defined(_WIN32)
  struct flock lock;
  pid_t mypid;

  mypid = getpid();
  memset(&lock, 0, sizeof(lock));
  lock.l_type = F_WRLCK;
  lock.l_start = 0;
  lock.l_whence = SEEK_SET;
  lock.l_len = 0;

  FileDescriptor fd(
      open(pid_file.c_str(), O_RDWR | O_CREAT, 0644),
      FileDescriptor::FDType::Generic);

  if (!fd) {
    log(ERR,
        "Failed to open pidfile ",
        pid_file,
        " for write: ",
        folly::errnoStr(errno),
        "\n");
    return false;
  }
  // Ensure that no children inherit the locked pidfile descriptor
  fd.setCloExec();

  if (fcntl(fd.fd(), F_SETLK, &lock) != 0) {
    char pidstr[32];
    int len;

    len = read(fd.fd(), pidstr, sizeof(pidstr) - 1);
    pidstr[len] = '\0';

    log(ERR,
        "Failed to lock pidfile ",
        pid_file,
        ": process ",
        pidstr,
        " owns it: ",
        folly::errnoStr(errno),
        "\n");
    return false;
  }

  // Replace contents of the pidfile with our pid string
  if (ftruncate(fd.fd(), 0)) {
    log(ERR,
        "Failed to truncate pidfile ",
        pid_file,
        ": ",
        folly::errnoStr(errno),
        "\n");
    return false;
  }

  auto pidString = folly::to<std::string>(mypid);
  ignore_result(write(fd.fd(), pidString.data(), pidString.size()));
  fsync(fd.fd());

  /* We are intentionally not closing the fd and intentionally not storing
   * a reference to it anywhere: the intention is that it remain locked
   * for the rest of the lifetime of our process.
   * close(fd); // NOPE!
   */
  fd.release();
  return true;
#else
  // One does not simply, and without risk of races, write a pidfile
  // on win32.  Instead we're using a named mutex in the global namespace.
  // This gives us a very simple way to exclusively claim ownership of
  // the lock for this user.  To make things a little more complicated,
  // since we scope our locks based on the state dir location and require
  // this to work for our integration tests, we need to create a unique
  // name per state dir.  This is made even more interesting because
  // we are forbidden from using windows directory separator characters
  // in the name, so we cannot simply concatenate the state dir path
  // with a watchman specific prefix.  Instead we iterate the path
  // and rewrite any backslashes with forward slashes and use that
  // for the name.
  // Using a mutex for this does make it more awkward to discover
  // the process id of the exclusive owner, but that's not critically
  // important; it is possible to connect to the instance and issue
  // a get-pid command if that is needed.

  // We use the global namespace so that we ensure that we have one
  // watchman process per user per state dir location.  If we didn't
  // use the Global namespace we'd end using a local namespace scoped
  // to the user session and that might cause confusion/insanity if
  // they are doing something elaborate like being logged in via
  // ssh in multiple sessions and expecting to share state.
  std::string name("Global\\Watchman-");
  for (const auto& it : pid_file) {
    if (it == '\\') {
      // We're not allowed to use backslash in the name, so normalize
      // to forward slashes.
      name.append("/");
    } else {
      name.push_back(it);
    }
  }

  auto mutex = CreateMutexA(nullptr, true, name.c_str());

  if (!mutex) {
    log(ERR,
        "Failed to create mutex named: ",
        name,
        ": ",
        GetLastError(),
        "\n");
    return false;
  }

  if (GetLastError() == ERROR_ALREADY_EXISTS) {
    log(ERR,
        "Failed to acquire mutex named: ",
        name,
        "; watchman is already running for this context\n");
    return false;
  }

  /* We are intentionally not closing the mutex and intentionally not storing
   * a reference to it anywhere: the intention is that it remain locked
   * for the rest of the lifetime of our process.
   * CloseHandle(mutex); // NOPE!
   */

  return true;
#endif
}

#ifndef _WIN32
// Returns the current process priority aka `nice` level.
// Since `-1` is a valid nice level, in order to detect an
// error we clear errno first and then test whether it is
// non-zero after we have retrieved the nice value.
static int get_nice_value() {
  errno = 0;
  auto value = nice(0);
  folly::checkPosixError(errno, "failed to get `nice` value");
  return value;
}

static void check_nice_value() {
  if (get_nice_value() > cfg_get_int("min_acceptable_nice_value", 0)) {
    log(watchman::FATAL,
        "Watchman is running at a lower than normal priority. Since that "
        "results in poor performance that is otherwise very difficult to "
        "trace, diagnose and debug, Watchman is refusing to start.\n");
  }
}
#endif

[[noreturn]] static void run_service() {
  int fd;
  bool res;

#ifndef _WIN32
  // Before we redirect stdin/stdout to the log files, move any inetd-provided
  // socket to a different descriptor number.
  if (inetd_style) {
    w_listener_prep_inetd();
  }
  if (isatty(0)) {
    // This case can happen when a user is running watchman using
    // the `--foreground` switch.
    // Check and raise this error before we detach from the terminal
    check_nice_value();
  }
#endif

  // redirect std{in,out,err}
  fd = ::open("/dev/null", O_RDONLY);
  if (fd != -1) {
    ignore_result(::dup2(fd, STDIN_FILENO));
    ::close(fd);
  }
  fd = open(log_name.c_str(), O_WRONLY | O_APPEND | O_CREAT, 0600);
  if (fd != -1) {
    ignore_result(::dup2(fd, STDOUT_FILENO));
    ignore_result(::dup2(fd, STDERR_FILENO));
    ::close(fd);
  }

#ifndef _WIN32
  // If we weren't attached to a tty, check this now that we've opened
  // the log files so that we can log the problem there.
  check_nice_value();
#endif

  if (!lock_pidfile()) {
    exit(1);
  }

#ifndef _WIN32
  /* we are the child, let's set things up */
  ignore_result(chdir("/"));
#endif

  w_set_thread_name("listener");
  {
    char hostname[256];
    gethostname(hostname, sizeof(hostname));
    hostname[sizeof(hostname) - 1] = '\0';
    logf(
        ERR,
        "Watchman {} {} starting up on {}\n",
        PACKAGE_VERSION,
#ifdef WATCHMAN_BUILD_INFO
        WATCHMAN_BUILD_INFO,
#else
        "<no build info set>",
#endif
        hostname);
  }

#ifndef _WIN32
  // Block SIGCHLD by default; we only want it to be delivered
  // to the reaper thread and only when it is ready to reap.
  // This MUST happen before we spawn any threads so that they
  // can pick up our default blocked signal mask.
  {
    sigset_t sigset;

    sigemptyset(&sigset);
    sigaddset(&sigset, SIGCHLD);
    sigprocmask(SIG_BLOCK, &sigset, NULL);
  }
#endif

  watchman::getThreadPool().start(
      cfg_get_int("thread_pool_worker_threads", 16),
      cfg_get_int("thread_pool_max_items", 1024 * 1024));

  ClockSpec::init();
  w_state_load();
  res = w_start_listener();
  w_root_free_watched_roots();
  perf_shutdown();
  cfg_shutdown();

  log(ERR, "Exiting from service with res=", res, "\n");

  if (res) {
    exit(0);
  }
  exit(1);
}

#ifndef _WIN32
// close any random descriptors that we may have inherited,
// leaving only the main stdio descriptors open, if we execute a
// child process.
static void close_random_fds(void) {
  struct rlimit limit;
  long open_max = 0;
  int max_fd;

  // Deduce the upper bound for number of descriptors
  limit.rlim_cur = 0;
#ifdef RLIMIT_NOFILE
  if (getrlimit(RLIMIT_NOFILE, &limit) != 0) {
    limit.rlim_cur = 0;
  }
#elif defined(RLIM_OFILE)
  if (getrlimit(RLIMIT_OFILE, &limit) != 0) {
    limit.rlim_cur = 0;
  }
#endif
#ifdef _SC_OPEN_MAX
  open_max = sysconf(_SC_OPEN_MAX);
#endif
  if (open_max <= 0) {
    open_max = 36; /* POSIX_OPEN_MAX (20) + some padding */
  }
  if (limit.rlim_cur == RLIM_INFINITY || limit.rlim_cur > INT_MAX) {
    // "no limit", which seems unlikely
    limit.rlim_cur = INT_MAX;
  }
  // Take the larger of the two values we compute
  if (limit.rlim_cur > (rlim_t)open_max) {
    open_max = limit.rlim_cur;
  }

  for (max_fd = open_max; max_fd > STDERR_FILENO; --max_fd) {
    close(max_fd);
  }
}
#endif

#if !defined(_WIN32)
static void daemonize(void) {
  // Make sure we're not about to inherit an undesirable nice value
  check_nice_value();
  close_random_fds();

  // the double-fork-and-setsid trick establishes a
  // child process that runs in its own process group
  // with its own session and that won't get killed
  // off when your shell exits (for example).
  if (fork()) {
    // The parent of the first fork is the client
    // process that is being run by the user, and
    // we want to allow that to continue.
    return;
  }
  setsid();
  if (fork()) {
    // The parent of the second fork has served its
    // purpose, so we simply exit here, otherwise
    // we'll duplicate the effort of either the
    // client or the server depending on if we
    // return or not.
    _exit(0);
  }

  // we are the child, let's set things up
  run_service();
}
#endif

#ifdef _WIN32
static void spawn_win32(void) {
  char module_name[WATCHMAN_NAME_MAX];
  GetModuleFileName(NULL, module_name, sizeof(module_name));

  Options opts;
  opts.setFlags(POSIX_SPAWN_SETPGROUP);
  opts.open(STDIN_FILENO, "/dev/null", O_RDONLY, 0666);
  opts.open(
      STDOUT_FILENO, log_name.c_str(), O_WRONLY | O_CREAT | O_APPEND, 0600);
  opts.dup2(STDOUT_FILENO, STDERR_FILENO);

  std::vector<w_string_piece> args{module_name, "--foreground"};
  for (size_t i = 0; daemon_argv[i]; i++) {
    args.push_back(daemon_argv[i]);
  }

  ChildProcess proc(args, std::move(opts));
  std::this_thread::sleep_for(std::chrono::milliseconds(500));
  if (proc.terminated()) {
    logf(
        ERR,
        "Failed to spawn watchman server; it exited with code {}.\n"
        "Check the log file at {} for more information\n",
        proc.wait(),
        log_name);
    exit(1);
  }
  proc.disown();
}
#endif

#ifndef _WIN32
// Spawn watchman via a site-specific spawn helper program.
// We'll pass along any daemon-appropriate arguments that
// we noticed during argument parsing.
static void spawn_site_specific(const char* spawner) {
  std::vector<w_string_piece> args{
      spawner,
  };

  for (size_t i = 0; daemon_argv[i]; i++) {
    args.push_back(daemon_argv[i]);
  }

  close_random_fds();

  // Note that we're not setting up the output to go to the log files
  // here.  This is intentional; we'd like any failures in the spawner
  // to bubble up to the user as having things silently fail and get
  // logged to the server log doesn't provide any obvious cues to the
  // user about what went wrong.  Watchman will open and redirect output
  // to its log files when it ultimately is launched and enters the
  // run_service() function above.
  // However, we do need to make sure that any output from both stdout
  // and stderr goes to stderr of the end user.
  Options opts;
  opts.open(STDIN_FILENO, "/dev/null", O_RDONLY, 0666);
  opts.dup2(STDERR_FILENO, STDOUT_FILENO);
  opts.dup2(STDERR_FILENO, STDERR_FILENO);

  try {
    ChildProcess proc(args, std::move(opts));

    auto res = proc.wait();

    if (WIFEXITED(res) && WEXITSTATUS(res) == 0) {
      return;
    }

    if (WIFEXITED(res)) {
      log(FATAL, spawner, ": exited with status ", WEXITSTATUS(res), "\n");
    } else if (WIFSIGNALED(res)) {
      log(FATAL, spawner, ": signaled with ", WTERMSIG(res), "\n");
    }
    log(FATAL, spawner, ": failed to start, exit status ", res, "\n");

  } catch (const std::exception& exc) {
    log(FATAL,
        "Failed to spawn watchman via `",
        spawner,
        "': ",
        exc.what(),
        "\n");
  }
}
#endif

#ifdef __APPLE__
static void spawn_via_launchd(void) {
  char watchman_path[WATCHMAN_NAME_MAX];
  uint32_t size = sizeof(watchman_path);
  char plist_path[WATCHMAN_NAME_MAX];
  FILE* fp;
  struct passwd* pw;
  uid_t uid;

  close_random_fds();

  if (_NSGetExecutablePath(watchman_path, &size) == -1) {
    log(FATAL, "_NSGetExecutablePath: path too long; size ", size, "\n");
  }

  uid = getuid();
  pw = getpwuid(uid);
  if (!pw) {
    log(FATAL,
        "getpwuid(",
        uid,
        ") failed: ",
        folly::errnoStr(errno),
        ".  I don't know who you are\n");
  }

  snprintf(
      plist_path, sizeof(plist_path), "%s/Library/LaunchAgents", pw->pw_dir);
  // Best effort attempt to ensure that the agents dir exists.  We'll detect
  // and report the failure in the fopen call below.
  mkdir(plist_path, 0755);
  snprintf(
      plist_path,
      sizeof(plist_path),
      "%s/Library/LaunchAgents/com.github.facebook.watchman.plist",
      pw->pw_dir);

  if (access(plist_path, R_OK) == 0) {
    // Unload any that may already exist, as it is likely wrong

    ChildProcess unload_proc(
        {"/bin/launchctl", "unload", "-F", plist_path}, Options());
    unload_proc.wait();

    // Forcibly remove the plist.  In some cases it may have some attributes
    // set that prevent launchd from loading it.  This can happen where
    // the system was re-imaged or restored from a backup
    unlink(plist_path);
  }

  fp = fopen(plist_path, "w");
  if (!fp) {
    log(FATAL,
        "Failed to open ",
        plist_path,
        " for write: ",
        folly::errnoStr(errno),
        "\n");
  }

  compute_file_name(pid_file, compute_user_name(), "pid", "pidfile");

  auto plist_content = folly::to<std::string>(
      "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
      "<!DOCTYPE plist PUBLIC \"-//Apple//DTD PLIST 1.0//EN\" "
      "\"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">\n"
      "<plist version=\"1.0\">\n"
      "<dict>\n"
      "    <key>Label</key>\n"
      "    <string>com.github.facebook.watchman</string>\n"
      "    <key>Disabled</key>\n"
      "    <false/>\n"
      "    <key>ProgramArguments</key>\n"
      "    <array>\n"
      "        <string>",
      watchman_path,
      "</string>\n"
      "        <string>--foreground</string>\n"
      "        <string>--logfile=",
      log_name,
      "</string>\n"
      "        <string>--log-level=",
      log_level,
      "</string>\n"
      // TODO: switch from `--sockname` to `--unix-listener-path`
      // after a grace period to allow for sane results if we
      // roll back to an earlier version
      "        <string>--sockname=",
      get_unix_sock_name(),
      "</string>\n"
      "        <string>--statefile=",
      watchman_state_file,
      "</string>\n"
      "        <string>--pidfile=",
      pid_file,
      "</string>\n"
      "    </array>\n"
      "    <key>KeepAlive</key>\n"
      "    <dict>\n"
      "        <key>Crashed</key>\n"
      "        <true/>\n"
      "    </dict>\n"
      "    <key>RunAtLoad</key>\n"
      "    <true/>\n"
      "    <key>EnvironmentVariables</key>\n"
      "    <dict>\n"
      "        <key>PATH</key>\n"
      "        <string><![CDATA[",
      getenv("PATH"),
      "]]></string>\n"
      "    </dict>\n"
      "    <key>ProcessType</key>\n"
      "    <string>Interactive</string>\n"
      "    <key>Nice</key>\n"
      "    <integer>-5</integer>\n"
      "</dict>\n"
      "</plist>\n");
  fwrite(plist_content.data(), 1, plist_content.size(), fp);
  fclose(fp);
  // Don't rely on umask, ensure we have the correct perms
  chmod(plist_path, 0644);

  ChildProcess load_proc(
      {"/bin/launchctl", "load", "-F", plist_path}, Options());
  auto res = load_proc.wait();

  if (WIFEXITED(res) && WEXITSTATUS(res) == 0) {
    return;
  }

  // Most likely cause is "headless" operation with no GUI context
  if (WIFEXITED(res)) {
    logf(ERR, "launchctl: exited with status {}\n", WEXITSTATUS(res));
  } else if (WIFSIGNALED(res)) {
    logf(ERR, "launchctl: signaled with {}\n", WTERMSIG(res));
  }
  logf(ERR, "Falling back to daemonize\n");
  daemonize();
}
#endif

static void parse_encoding(const std::string& enc, enum w_pdu_type* pdu) {
  if (enc.empty()) {
    return;
  }
  if (enc == "json") {
    *pdu = is_json_compact;
    return;
  }
  if (enc == "bser") {
    *pdu = is_bser;
    return;
  }
  if (enc == "bser-v2") {
    *pdu = is_bser_v2;
    return;
  }
  log(ERR, "Invalid encoding '", enc, "', use one of json, bser or bser-v2\n");
  exit(EX_USAGE);
}

static const char* get_env_with_fallback(
    const char* name1,
    const char* name2,
    const char* fallback) {
  const char* val;

  val = getenv(name1);
  if (!val || *val == 0) {
    val = getenv(name2);
  }
  if (!val || *val == 0) {
    val = fallback;
  }

  return val;
}

static void verify_dir_ownership(const std::string& state_dir) {
#ifndef _WIN32
  // verify ownership
  struct stat st;
  int dir_fd;
  int ret = 0;
  uid_t euid = geteuid();
  // TODO: also allow a gid to be specified here
  const char* sock_group_name = cfg_get_string("sock_group", nullptr);
  // S_ISGID is set so that files inside this directory inherit the group
  // name
  mode_t dir_perms =
      cfg_get_perms(
          "sock_access", false /* write bits */, true /* execute bits */) |
      S_ISGID;

  auto dirp = w_dir_open(
      state_dir.c_str(), false /* don't need strict symlink rules */);

  dir_fd = dirp->getFd();
  if (dir_fd == -1) {
    log(ERR, "dirfd(", state_dir, "): ", folly::errnoStr(errno), "\n");
    goto bail;
  }

  if (fstat(dir_fd, &st) != 0) {
    log(ERR, "fstat(", state_dir, "): ", folly::errnoStr(errno), "\n");
    ret = 1;
    goto bail;
  }
  if (euid != st.st_uid) {
    log(ERR,
        "the owner of ",
        state_dir,
        " is uid ",
        st.st_uid,
        " and doesn't match your euid ",
        euid,
        "\n");
    ret = 1;
    goto bail;
  }
  if (st.st_mode & 0022) {
    log(ERR,
        "the permissions on ",
        state_dir,
        " allow others to write to it. "
        "Verify that you own the contents and then fix its "
        "permissions by running `chmod 0700 '",
        state_dir,
        "'`\n");
    ret = 1;
    goto bail;
  }

  if (sock_group_name) {
    const struct group* sock_group = w_get_group(sock_group_name);
    if (!sock_group) {
      ret = 1;
      goto bail;
    }

    if (fchown(dir_fd, -1, sock_group->gr_gid) == -1) {
      log(ERR,
          "setting up group '",
          sock_group_name,
          "' failed: ",
          folly::errnoStr(errno),
          "\n");
      ret = 1;
      goto bail;
    }
  }

  // Depending on group and world accessibility, change permissions on the
  // directory. We can't leave the directory open and set permissions on the
  // socket because not all POSIX systems respect permissions on UNIX domain
  // sockets, but all POSIX systems respect permissions on the containing
  // directory.
  logf(DBG, "Setting permissions on state dir to {:o}\n", dir_perms);
  if (fchmod(dir_fd, dir_perms) == -1) {
    logf(
        ERR,
        "fchmod({}, {:o}): {}\n",
        state_dir,
        dir_perms,
        folly::errnoStr(errno));
    ret = 1;
    goto bail;
  }

bail:
  if (ret) {
    exit(ret);
  }
#endif
}

#ifdef _WIN32
static std::string get_watchman_appdata_path() {
  PWSTR local_app_data = nullptr;
  auto res =
      SHGetKnownFolderPath(FOLDERID_LocalAppData, 0, nullptr, &local_app_data);
  if (res != S_OK) {
    logf(
        FATAL,
        "SHGetKnownFolderPath FOLDERID_LocalAppData failed: {}\n",
        win32_strerror(res));
  }
  SCOPE_EXIT {
    CoTaskMemFree(local_app_data);
  };
  // Perform path mapping from wide string to our preferred UTF8
  w_string temp_location(local_app_data, wcslen(local_app_data));
  // and use the watchman subdir of LOCALAPPDATA
  auto watchmanDir = folly::to<std::string>(temp_location, "/watchman");
  if (mkdir(watchmanDir.c_str(), 0700) == 0 || errno == EEXIST) {
    return watchmanDir;
  }
  logf(
      ERR,
      "failed to create directory {}: {}\n",
      watchmanDir,
      folly::errnoStr(errno));
  exit(1);
}

static const std::string& cached_watchman_appdata_path() {
  static std::string path = get_watchman_appdata_path();
  return path;
}
#endif

static std::string compute_per_user_state_dir(const std::string& user) {
  if (!test_state_dir.empty()) {
    return folly::to<std::string>(test_state_dir, "/", user, "-state");
  }

#ifdef _WIN32
  return cached_watchman_appdata_path();
#else
  auto state_parent =
#ifdef WATCHMAN_STATE_DIR
      WATCHMAN_STATE_DIR
#else
      watchman_tmp_dir.c_str()
#endif
      ;
  return folly::to<std::string>(state_parent, "/", user, "-state");
#endif
}

static void compute_file_name(
    std::string& str,
    const std::string& user,
    const char* suffix,
    const char* what) {
  bool str_computed = false;
  if (str.empty()) {
    str_computed = true;
    /* We'll put our various artifacts in a user specific dir
     * within the state dir location */
    auto state_dir = compute_per_user_state_dir(user);

    if (mkdir(state_dir.c_str(), 0700) == 0 || errno == EEXIST) {
      verify_dir_ownership(state_dir.c_str());
    } else {
      log(ERR,
          "while computing ",
          what,
          ": failed to create ",
          state_dir,
          ": ",
          folly::errnoStr(errno),
          "\n");
      exit(1);
    }

    str = folly::to<std::string>(state_dir, "/", suffix);
  }
#ifndef _WIN32
  if (!w_string_piece(str).pathIsAbsolute()) {
    log(FATAL,
        what,
        " must be an absolute file path but ",
        str,
        " was",
        str_computed ? " computed." : " provided.",
        "\n");
  }
#endif
}

static std::string compute_user_name(void) {
#ifdef _WIN32
  // We don't trust the environment on win32 because in some situations
  // the environment may contain the domain name like `WORKGROUP\user`
  // which can confuse some path construction we do later on.
  WCHAR userW[1 + UNLEN];
  DWORD size = std::size(userW);
  if (GetUserNameW(userW, &size) && size > 0) {
    // Constructing a w_string from a WCHAR* will convert to UTF-8
    w_string user(userW, size);
    return folly::to<std::string>(user);
  }

  log(FATAL,
      "GetUserName failed: ",
      win32_strerror(GetLastError()),
      ". I don't know who you are!?\n");
#else
  const char* user = get_env_with_fallback("USER", "LOGNAME", NULL);

  if (!user) {
    uid_t uid = getuid();
    struct passwd* pw;

    pw = getpwuid(uid);
    if (!pw) {
      log(FATAL,
          "getpwuid(",
          uid,
          ") failed: ",
          folly::errnoStr(errno),
          ". I don't know who you are\n");
    }

    user = pw->pw_name;

    if (!user) {
      log(FATAL, "watchman requires that you set $USER in your env\n");
    }
  }

  return user;
#endif
}

#ifdef _WIN32
bool initialize_winsock() {
  WSADATA wsaData;
  if ((WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) ||
      (LOBYTE(wsaData.wVersion) != 2 || HIBYTE(wsaData.wVersion) != 2)) {
    return false;
  }
  return true;
}

bool initialize_uds() {
  if (!initialize_winsock()) {
    log(DBG, "unable to initialize winsock, disabling UDS support\n");
  }

  // Test if UDS support is present
  FileDescriptor fd(
      ::socket(PF_LOCAL, SOCK_STREAM, 0), FileDescriptor::FDType::Socket);

  bool fd_initialized = (bool)fd;

  if (!fd_initialized) {
    log(DBG, "unable to create UNIX domain socket, disabling UDS support\n");
    return false;
  }

  return true;
}
#endif

static void setup_sock_name(void) {
#ifdef _WIN32
  if (!initialize_uds()) {
    // if we can't create UNIX domain socket, disable it.
    disable_unix_socket = true;
  }
#endif

  auto user = compute_user_name();

#ifdef _WIN32
  if (!test_state_dir.empty()) {
    watchman_tmp_dir = test_state_dir;
  } else {
    watchman_tmp_dir = cached_watchman_appdata_path();
  }
#else
  watchman_tmp_dir = get_env_with_fallback("TMPDIR", "TMP", "/tmp");
#endif

#ifdef _WIN32
  // On Windows, if an application uses --sockname to override the named
  // pipe path so that it can isolate its watchman integration tests,
  // but doesn't also specify --unix-listener-path then we need to
  // take care to prevent using the default unix domain path which would
  // otherwise break their isolation.
  // If either option is specified without the other, then we disable
  // the use of the other.
  if (!named_pipe_path.empty() || !unix_sock_name.empty()) {
    disable_named_pipe = named_pipe_path.empty();
    disable_unix_socket = unix_sock_name.empty();
  }

  if (named_pipe_path.empty()) {
    named_pipe_path = folly::to<std::string>("\\\\.\\pipe\\watchman-", user);
  }
#endif
  compute_file_name(unix_sock_name, user, "sock", "sockname");

  compute_file_name(watchman_state_file, user, "state", "statefile");
  compute_file_name(log_name, user, "log", "logfile");

  if (unix_sock_name.size() >= sizeof(un.sun_path) - 1) {
    log(FATAL, unix_sock_name, ": path is too long\n");
  }
  un.sun_family = PF_LOCAL;
  memcpy(un.sun_path, unix_sock_name.c_str(), unix_sock_name.size() + 1);
}

static bool should_start(int err) {
  if (err == ECONNREFUSED) {
    return true;
  }
  if (err == ENOENT) {
    return true;
  }
  return false;
}

static bool try_command(json_t* cmd, int timeout) {
  auto client = w_stm_connect(timeout * 1000);
  if (!client) {
    return false;
  }

  // Start in a well-defined non-blocking state as we can't tell
  // what mode we're in on windows until we've set it to something
  // explicitly at least once before!
  client->setNonBlock(false);

  if (!cmd) {
    return true;
  }

  w_jbuffer_t buffer;
  w_jbuffer_t output_pdu_buffer;

  // Send command
  if (!buffer.pduEncodeToStream(
          server_pdu, server_capabilities, cmd, client.get())) {
    int err = errno;
    logf(ERR, "error sending PDU to server\n");
    errno = err;
    return false;
  }

  buffer.clear();

  do {
    if (!buffer.passThru(
            output_pdu,
            output_capabilities,
            &output_pdu_buffer,
            client.get())) {
      return false;
    }
  } while (persistent);

  return true;
}

static struct watchman_getopt opts[] = {
    {"help", 'h', "Show this help", OPT_NONE, &show_help, NULL, NOT_DAEMON},
#ifndef _WIN32
    {"inetd",
     0,
     "Spawning from an inetd style supervisor",
     OPT_NONE,
     &inetd_style,
     NULL,
     IS_DAEMON},
#endif
    {"no-site-spawner",
     'S',
     "Don't use the site or system spawner",
     OPT_NONE,
     &no_site_spawner,
     NULL,
     IS_DAEMON},
    {"version",
     'v',
     "Show version number",
     OPT_NONE,
     &show_version,
     NULL,
     NOT_DAEMON},
/* -U / --sockname  have legacy meaning; unix domain on unix,
 * named pipe path on windows.  After we chose this assignment,
 * Windows evolved unix domain support which muddies this.
 * We need to preserve the sockname/U option here for backwards
 * compatibility */
#ifdef _WIN32
    {"sockname",
     'U',
     "DEPRECATED: Specify alternate named pipe path (specifying this will"
     " disable unix domain sockets unless `--unix-listener-path` is"
     " specified)",
     REQ_STRING,
     &named_pipe_path,
     "PATH",
     IS_DAEMON},
#else
    {"sockname",
     'U',
     "DEPRECATED: Specify alternate sockname. Use `--unix-listener-path` instead.",
     REQ_STRING,
     &unix_sock_name,
     "PATH",
     IS_DAEMON},
#endif
    {"named-pipe-path",
     0,
     "Specify alternate named pipe path",
     REQ_STRING,
     &named_pipe_path,
     "PATH",
     IS_DAEMON},
    {"unix-listener-path",
     'u',
#ifdef _WIN32
     "Specify alternate unix domain socket path (specifying this will disable"
     " named pipes unless `--named-pipe-path` is specified)",
#else
     "Specify alternate unix domain socket path",
#endif
     REQ_STRING,
     &unix_sock_name,
     "PATH",
     IS_DAEMON},
    {"tcp-listener-enable",
     't',
     "Enable listening on TCP; see also tcp-listener-address and tcp-listener-port",
     OPT_NONE,
     &enable_tcp,
     nullptr,
     IS_DAEMON},
    {"tcp-listener-address",
     0,
     "Specify in <address>:<port> the address to bind to and listen on when tcp-listener-enable is true",
     REQ_STRING,
     &tcp_host,
     "ADDRESS",
     IS_DAEMON},
    {"logfile",
     'o',
     "Specify path to logfile",
     REQ_STRING,
     &log_name,
     "PATH",
     IS_DAEMON},
    {"log-level",
     0,
     "set the log level (0 = off, default is 1, verbose = 2)",
     REQ_INT,
     &log_level,
     NULL,
     IS_DAEMON},
    {"pidfile",
     0,
     "Specify path to pidfile",
     REQ_STRING,
     &pid_file,
     "PATH",
     IS_DAEMON},
    {"persistent",
     'p',
     "Persist and wait for further responses",
     OPT_NONE,
     &persistent,
     NULL,
     NOT_DAEMON},
    {"no-save-state",
     'n',
     "Don't save state between invocations",
     OPT_NONE,
     &dont_save_state,
     NULL,
     IS_DAEMON},
    {"statefile",
     0,
     "Specify path to file to hold watch and trigger state",
     REQ_STRING,
     &watchman_state_file,
     "PATH",
     IS_DAEMON},
    {"json-command",
     'j',
     "Instead of parsing CLI arguments, take a single "
     "json object from stdin",
     OPT_NONE,
     &json_input_arg,
     NULL,
     NOT_DAEMON},
    {"output-encoding",
     0,
     "CLI output encoding. json (default) or bser",
     REQ_STRING,
     &output_encoding,
     NULL,
     NOT_DAEMON},
    {"server-encoding",
     0,
     "CLI<->server encoding. bser (default) or json",
     REQ_STRING,
     &server_encoding,
     NULL,
     NOT_DAEMON},
    {"foreground",
     'f',
     "Run the service in the foreground",
     OPT_NONE,
     &foreground,
     NULL,
     NOT_DAEMON},
    {"no-pretty",
     0,
     "Don't pretty print JSON",
     OPT_NONE,
     &no_pretty,
     NULL,
     NOT_DAEMON},
    {"no-spawn",
     0,
     "Don't try to start the service if it is not available",
     OPT_NONE,
     &no_spawn,
     NULL,
     NOT_DAEMON},
    {"no-local",
     0,
     "When no-spawn is enabled, don't try to handle request"
     " in client mode if service is unavailable",
     OPT_NONE,
     &no_local,
     NULL,
     NOT_DAEMON},
    // test-state-dir is for testing only and should not be used in production:
    // instead, use the compile-time WATCHMAN_STATE_DIR option
    {"test-state-dir", 0, NULL, REQ_STRING, &test_state_dir, "DIR", NOT_DAEMON},
    {0, 0, 0, OPT_NONE, 0, 0, 0}};

static void parse_cmdline(int* argcp, char*** argvp) {
  cfg_load_global_config_file();
  w_getopt(opts, argcp, argvp, &daemon_argv);
  if (show_help) {
    usage(opts, stdout);
  }
  if (show_version) {
    printf("%s\n", PACKAGE_VERSION);
    exit(0);
  }
  watchman::getLog().setStdErrLoggingLevel(
      static_cast<enum watchman::LogLevel>(log_level));
  setup_sock_name();
  parse_encoding(server_encoding, &server_pdu);
  parse_encoding(output_encoding, &output_pdu);
  if (output_encoding.empty()) {
    output_pdu = no_pretty ? is_json_compact : is_json_pretty;
  }

  // Prevent integration tests that call the watchman cli from
  // accidentally spawning a server.
  if (getenv("WATCHMAN_NO_SPAWN")) {
    no_spawn = true;
  }

  if (Configuration().getBool("tcp-listener-enable", false)) {
    // hg requires the state-enter/state-leave commands, which are disabled over
    // TCP by default since at present it is unauthenticated. This should be
    // removed once TLS authentication is added to the TCP listener.
    // TODO: When this code is removed, lookup() can be changed to return a
    // const pointer.
    lookup_command(w_string("state-enter"), CMD_DAEMON)->flags |=
        CMD_ALLOW_ANY_USER;
    lookup_command(w_string("state-leave"), CMD_DAEMON)->flags |=
        CMD_ALLOW_ANY_USER;
  }
}

static json_ref build_command(int argc, char** argv) {
  // Read blob from stdin
  if (json_input_arg) {
    auto err = json_error_t();
    w_jbuffer_t buf;

    auto cmd = buf.decodeNext(w_stm_stdin(), &err);

    if (buf.pdu_type == is_bser) {
      // If they used bser for the input, select bser for output
      // unless they explicitly requested something else
      if (server_encoding.empty()) {
        server_pdu = is_bser;
      }
      if (output_encoding.empty()) {
        output_pdu = is_bser;
      }
    } else if (buf.pdu_type == is_bser_v2) {
      // If they used bser v2 for the input, select bser v2 for output
      // unless they explicitly requested something else
      if (server_encoding.empty()) {
        server_pdu = is_bser_v2;
      }
      if (output_encoding.empty()) {
        output_pdu = is_bser_v2;
      }
    }

    if (!cmd) {
      fprintf(
          stderr,
          "failed to parse command from stdin: "
          "line %d, column %d, position %d: %s\n",
          err.line,
          err.column,
          err.position,
          err.text);
      exit(1);
    }
    return cmd;
  }

  // Special case: no arguments means that we just want
  // to verify that the service is up, starting it if
  // needed
  if (argc == 0) {
    return nullptr;
  }

  auto cmd = json_array();
  for (int i = 0; i < argc; i++) {
    json_array_append_new(cmd, typed_string_to_json(argv[i], W_STRING_UNICODE));
  }

  return cmd;
}

static void spawn_watchman(void) {
#ifndef _WIN32
  if (no_site_spawner) {
    // The astute reader will notice this we're calling daemonize() here
    // and not the various other platform spawning functions in the block
    // further below in this function.  This is deliberate: we want
    // to do the most simple background running possible when the
    // no_site_spawner flag is used.   In the future we plan to
    // migrate the platform spawning functions to use the site_spawn
    // functionality.
    daemonize();
    return;
  }
  // If we have a site-specific spawning requirement, then we'll
  // invoke that spawner rather than using any of the built-in
  // spawning functionality.
  const char* site_spawn = cfg_get_string("spawn_watchman_service", nullptr);
  if (site_spawn) {
    spawn_site_specific(site_spawn);
    return;
  }
#endif

#if defined(__APPLE__)
  spawn_via_launchd();
#elif defined(_WIN32)
  spawn_win32();
#else
  daemonize();
#endif
}

static int inner_main(int argc, char** argv) {
#ifdef _WIN32
  // On Windows its not possible to connect to elevated Watchman daemon from
  // non-elevated processes. To ensure that Watchman daemon will always be
  // accessible, deelevating it if needed.
  deelevate_requires_normal_privileges();
#endif

  // Since we don't fully integrate with folly, but may pull
  // in dependencies that do, we need to perform a little bit
  // of bootstrapping.  We don't want to run the full folly
  // init today because it will interfere with our own signal
  // handling.  In the future we will integrate this properly.
  folly::SingletonVault::singleton()->registrationComplete();
  SCOPE_EXIT {
    folly::SingletonVault::singleton()->destroyInstances();
  };

  parse_cmdline(&argc, &argv);

  if (foreground) {
    run_service();
    return 0;
  }

  w_set_thread_name("cli");
  auto cmd = build_command(argc, argv);
  preprocess_command(cmd, output_pdu, output_capabilities);

  bool ran = try_command(cmd, 0);
  if (!ran && should_start(errno)) {
    if (no_spawn) {
      if (!no_local) {
        ran = try_client_mode_command(cmd, !no_pretty);
      }
    } else {
      spawn_watchman();
      // Some site spawner scripts will asynchronously launch the service.
      // When that happens we may encounter ECONNREFUSED.  We need to
      // tolerate this, so we add some retries.
      int attempts = 10;
      std::chrono::milliseconds interval(10);
      while (true) {
        ran = try_command(cmd, 10);
        if (!ran && should_start(errno) && attempts-- > 0) {
          /* sleep override */ std::this_thread::sleep_for(interval);
          interval *= 2;
          continue;
        }
        // Success or terminal failure
        break;
      }
    }
  }

  if (ran) {
    return 0;
  }

  if (!no_spawn) {
    log(ERR,
        "unable to talk to your watchman on ",
        get_sock_name_legacy(),
        "! (",
        folly::errnoStr(errno),
        ")\n");
#ifdef __APPLE__
    if (getenv("TMUX")) {
      logf(
          ERR,
          "\n"
          "You may be hitting a tmux related session issue.\n"
          "An immediate workaround is to run:\n"
          "\n"
          "    watchman version\n"
          "\n"
          "just once, from *outside* your tmux session, to allow the launchd\n"
          "registration to be setup.  Once done, you can continue to access\n"
          "watchman from inside your tmux sessions as usual.\n"
          "\n"
          "Longer term, you may wish to install this tool:\n"
          "\n"
          "    https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard\n"
          "\n"
          "and configure tmux to use `reattach-to-user-namespace`\n"
          "when it launches your shell.\n");
    }
#endif
  }
  return 1;
}

int main(int argc, char** argv) {
  try {
    return inner_main(argc, argv);
  } catch (const std::exception& e) {
    log(ERR,
        "Uncaught C++ exception: ",
        folly::exceptionStr(e).toStdString(),
        "\n");
    return 1;
  } catch (...) {
    log(ERR, "Uncaught C++ exception: ...\n");
    return 1;
  }
}

/* vim:ts=2:sw=2:et:
 */