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dyn_load.c
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/*
* Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
* Copyright (c) 1997 by Silicon Graphics. All rights reserved.
* Copyright (c) 2009-2022 Ivan Maidanski
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*/
#include "private/gc_priv.h"
/*
* This is incredibly OS specific code for tracking down data sections in
* dynamic libraries. There appears to be no way of doing this quickly
* without groveling through undocumented data structures. We would argue
* that this is a bug in the design of the dlopen interface. THIS CODE
* MAY BREAK IN FUTURE OS RELEASES. If this matters to you, don't hesitate
* to let your vendor know ...
*
* None of this is safe with dlclose and incremental collection.
* But then not much of anything is safe in the presence of dlclose.
*/
#if !defined(MACOS) && !defined(GC_NO_TYPES) && !defined(SN_TARGET_PSP2) \
&& !defined(_WIN32_WCE) && !defined(__CC_ARM)
# include <sys/types.h>
#endif
/* BTL: avoid circular redefinition of dlopen if GC_SOLARIS_THREADS defined */
#undef GC_MUST_RESTORE_REDEFINED_DLOPEN
#if defined(GC_PTHREADS) && !defined(GC_NO_DLOPEN) \
&& !defined(GC_NO_THREAD_REDIRECTS) && !defined(GC_USE_LD_WRAP)
/* To support threads in Solaris, gc.h interposes on dlopen by */
/* defining "dlopen" to be "GC_dlopen", which is implemented below. */
/* However, both GC_FirstDLOpenedLinkMap() and GC_dlopen() use the */
/* real system dlopen() in their implementation. We first remove */
/* gc.h's dlopen definition and restore it later, after GC_dlopen(). */
# undef dlopen
# define GC_MUST_RESTORE_REDEFINED_DLOPEN
#endif /* !GC_NO_DLOPEN */
/* A user-supplied routine (custom filter) that might be called to */
/* determine whether a DSO really needs to be scanned by the GC. */
/* 0 means no filter installed. May be unused on some platforms. */
/* FIXME: Add filter support for more platforms. */
STATIC GC_has_static_roots_func GC_has_static_roots = 0;
#if (defined(DYNAMIC_LOADING) || defined(MSWIN32) || defined(MSWINCE) \
|| defined(CYGWIN32)) && !defined(PCR)
#if !defined(DARWIN) && !defined(SCO_ELF) && !defined(SOLARISDL) \
&& !defined(AIX) && !defined(DGUX) && !defined(IRIX5) && !defined(HPUX) \
&& !defined(CYGWIN32) && !defined(MSWIN32) && !defined(MSWINCE) \
&& !(defined(ALPHA) && defined(OSF1)) \
&& !(defined(FREEBSD) && defined(__ELF__)) \
&& !(defined(LINUX) && defined(__ELF__)) \
&& !(defined(NETBSD) && defined(__ELF__)) \
&& !(defined(OPENBSD) && (defined(__ELF__) || defined(M68K))) \
&& !defined(HAIKU) && !defined(HURD) && !defined(NACL) \
&& !defined(CPPCHECK)
# error We only know how to find data segments of dynamic libraries for above.
# error Additional SVR4 variants might not be too hard to add.
#endif
#ifdef SOLARISDL
# include <sys/elf.h>
# include <dlfcn.h>
# include <link.h>
#endif
#if defined(NETBSD)
# include <sys/param.h>
# include <dlfcn.h>
# include <machine/elf_machdep.h>
# define ELFSIZE ARCH_ELFSIZE
#endif
#if defined(OPENBSD)
# include <sys/param.h>
# if (OpenBSD >= 200519) && !defined(HAVE_DL_ITERATE_PHDR)
# define HAVE_DL_ITERATE_PHDR
# endif
#endif /* OPENBSD */
#if defined(SCO_ELF) || defined(DGUX) || defined(HURD) || defined(NACL) \
|| (defined(__ELF__) && (defined(LINUX) || defined(FREEBSD) \
|| defined(NETBSD) || defined(OPENBSD)))
# include <stddef.h>
# if !defined(OPENBSD) && !defined(HOST_ANDROID)
/* OpenBSD does not have elf.h file; link.h below is sufficient. */
/* Exclude Android because linker.h below includes its own version. */
# include <elf.h>
# endif
# ifdef HOST_ANDROID
/* If you don't need the "dynamic loading" feature, you may build */
/* the collector with -D IGNORE_DYNAMIC_LOADING. */
# ifdef BIONIC_ELFDATA_REDEF_BUG
/* Workaround a problem in Bionic (as of Android 4.2) which has */
/* mismatching ELF_DATA definitions in sys/exec_elf.h and */
/* asm/elf.h included from linker.h file (similar to EM_ALPHA). */
# include <asm/elf.h>
# include <linux/elf-em.h>
# undef ELF_DATA
# undef EM_ALPHA
# endif
# include <link.h>
# if !defined(GC_DONT_DEFINE_LINK_MAP) && !(__ANDROID_API__ >= 21)
/* link_map and r_debug are defined in link.h of NDK r10+. */
/* bionic/linker/linker.h defines them too but the header */
/* itself is a C++ one starting from Android 4.3. */
struct link_map {
uintptr_t l_addr;
char* l_name;
uintptr_t l_ld;
struct link_map* l_next;
struct link_map* l_prev;
};
struct r_debug {
int32_t r_version;
struct link_map* r_map;
void (*r_brk)(void);
int32_t r_state;
uintptr_t r_ldbase;
};
# endif
# else
EXTERN_C_BEGIN /* Workaround missing extern "C" around _DYNAMIC */
/* symbol in link.h of some Linux hosts. */
# include <link.h>
EXTERN_C_END
# endif
#endif
/* Newer versions of GNU/Linux define this macro. We
* define it similarly for any ELF systems that don't. */
# ifndef ElfW
# if defined(FREEBSD)
# if __ELF_WORD_SIZE == 32
# define ElfW(type) Elf32_##type
# else
# define ElfW(type) Elf64_##type
# endif
# elif defined(NETBSD) || defined(OPENBSD)
# if ELFSIZE == 32
# define ElfW(type) Elf32_##type
# elif ELFSIZE == 64
# define ElfW(type) Elf64_##type
# else
# error Missing ELFSIZE define
# endif
# else
# if !defined(ELF_CLASS) || ELF_CLASS == ELFCLASS32
# define ElfW(type) Elf32_##type
# else
# define ElfW(type) Elf64_##type
# endif
# endif
# endif
#if defined(SOLARISDL) && !defined(USE_PROC_FOR_LIBRARIES)
EXTERN_C_BEGIN
extern ElfW(Dyn) _DYNAMIC;
EXTERN_C_END
STATIC struct link_map *
GC_FirstDLOpenedLinkMap(void)
{
ElfW(Dyn) *dp;
static struct link_map * cachedResult = 0;
static ElfW(Dyn) *dynStructureAddr = 0;
/* BTL: added to avoid Solaris 5.3 ld.so _DYNAMIC bug */
# ifdef SUNOS53_SHARED_LIB
/* BTL: Avoid the Solaris 5.3 bug that _DYNAMIC isn't being set */
/* up properly in dynamically linked .so's. This means we have */
/* to use its value in the set of original object files loaded */
/* at program startup. */
if( dynStructureAddr == 0 ) {
void* startupSyms = dlopen(0, RTLD_LAZY);
dynStructureAddr = (ElfW(Dyn)*)(word)dlsym(startupSyms, "_DYNAMIC");
}
# else
dynStructureAddr = &_DYNAMIC;
# endif
if (0 == COVERT_DATAFLOW(dynStructureAddr)) {
/* _DYNAMIC symbol not resolved. */
return NULL;
}
if (cachedResult == 0) {
int tag;
for( dp = ((ElfW(Dyn) *)(&_DYNAMIC)); (tag = dp->d_tag) != 0; dp++ ) {
if (tag == DT_DEBUG) {
struct r_debug *rd = (struct r_debug *)dp->d_un.d_ptr;
if (rd != NULL) {
struct link_map *lm = rd->r_map;
if (lm != NULL)
cachedResult = lm->l_next; /* might be NULL */
}
break;
}
}
}
return cachedResult;
}
#endif /* SOLARISDL ... */
/* BTL: added to fix circular dlopen definition if GC_SOLARIS_THREADS defined */
# ifdef GC_MUST_RESTORE_REDEFINED_DLOPEN
# define dlopen GC_dlopen
# endif
# if defined(SOLARISDL)
/* Add dynamic library data sections to the root set. */
# if !defined(PCR) && !defined(GC_SOLARIS_THREADS) && defined(THREADS) \
&& !defined(CPPCHECK)
# error Fix mutual exclusion with dlopen
# endif
# ifndef USE_PROC_FOR_LIBRARIES
GC_INNER void GC_register_dynamic_libraries(void)
{
struct link_map *lm;
GC_ASSERT(I_HOLD_LOCK());
for (lm = GC_FirstDLOpenedLinkMap(); lm != 0; lm = lm->l_next) {
ElfW(Ehdr) * e;
ElfW(Phdr) * p;
unsigned long offset;
char * start;
int i;
e = (ElfW(Ehdr) *) lm->l_addr;
p = ((ElfW(Phdr) *)(((char *)(e)) + e->e_phoff));
offset = ((unsigned long)(lm->l_addr));
for( i = 0; i < (int)e->e_phnum; i++, p++ ) {
switch( p->p_type ) {
case PT_LOAD:
{
if( !(p->p_flags & PF_W) ) break;
start = ((char *)(p->p_vaddr)) + offset;
GC_add_roots_inner(start, start + p->p_memsz, TRUE);
}
break;
default:
break;
}
}
}
}
# endif /* !USE_PROC_FOR_LIBRARIES */
# endif /* SOLARISDL */
#if defined(SCO_ELF) || defined(DGUX) || defined(HURD) || defined(NACL) \
|| (defined(__ELF__) && (defined(LINUX) || defined(FREEBSD) \
|| defined(NETBSD) || defined(OPENBSD)))
#ifdef USE_PROC_FOR_LIBRARIES
#include <string.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#define MAPS_BUF_SIZE (32*1024)
/* Sort an array of HeapSects by start address. */
/* Unfortunately at least some versions of */
/* Linux qsort end up calling malloc by way of sysconf, and hence can't */
/* be used in the collector. Hence we roll our own. Should be */
/* reasonably fast if the array is already mostly sorted, as we expect */
/* it to be. */
static void sort_heap_sects(struct HeapSect *base, size_t number_of_elements)
{
signed_word n = (signed_word)number_of_elements;
signed_word nsorted = 1;
while (nsorted < n) {
signed_word i;
while (nsorted < n &&
(word)base[nsorted-1].hs_start < (word)base[nsorted].hs_start)
++nsorted;
if (nsorted == n) break;
GC_ASSERT((word)base[nsorted-1].hs_start > (word)base[nsorted].hs_start);
i = nsorted - 1;
while (i >= 0 && (word)base[i].hs_start > (word)base[i+1].hs_start) {
struct HeapSect tmp = base[i];
base[i] = base[i+1];
base[i+1] = tmp;
--i;
}
GC_ASSERT((word)base[nsorted-1].hs_start < (word)base[nsorted].hs_start);
++nsorted;
}
}
STATIC void GC_register_map_entries(const char *maps)
{
const char *prot, *path;
ptr_t start, end;
unsigned int maj_dev;
ptr_t least_ha, greatest_ha;
unsigned i;
GC_ASSERT(I_HOLD_LOCK());
sort_heap_sects(GC_our_memory, GC_n_memory);
least_ha = GC_our_memory[0].hs_start;
greatest_ha = GC_our_memory[GC_n_memory-1].hs_start
+ GC_our_memory[GC_n_memory-1].hs_bytes;
for (;;) {
maps = GC_parse_map_entry(maps, &start, &end, &prot, &maj_dev, &path);
if (NULL == maps) break;
if (prot[1] == 'w') {
/* This is a writable mapping. Add it to */
/* the root set unless it is already otherwise */
/* accounted for. */
if ((word)start <= (word)GC_stackbottom
&& (word)end >= (word)GC_stackbottom) {
/* Stack mapping; discard */
continue;
}
# if defined(E2K) && defined(__ptr64__)
/* TODO: avoid hard-coded addresses */
if ((word)start == 0xc2fffffff000UL
&& (word)end == 0xc30000000000UL && path[0] == '\n')
continue; /* discard some special mapping */
# endif
if (path[0] == '[' && strncmp(path+1, "heap]", 5) != 0)
continue; /* discard if a pseudo-path unless "[heap]" */
# ifdef THREADS
/* This may fail, since a thread may already be */
/* unregistered, but its thread stack may still be there. */
/* That can fail because the stack may disappear while */
/* we're marking. Thus the marker is, and has to be */
/* prepared to recover from segmentation faults. */
if (GC_segment_is_thread_stack(start, end)) continue;
/* FIXME: NPTL squirrels */
/* away pointers in pieces of the stack segment that we */
/* don't scan. We work around this */
/* by treating anything allocated by libpthread as */
/* uncollectible, as we do in some other cases. */
/* A specifically identified problem is that */
/* thread stacks contain pointers to dynamic thread */
/* vectors, which may be reused due to thread caching. */
/* They may not be marked if the thread is still live. */
/* This specific instance should be addressed by */
/* INCLUDE_LINUX_THREAD_DESCR, but that doesn't quite */
/* seem to suffice. */
/* We currently trace entire thread stacks, if they are */
/* are currently cached but unused. This is */
/* very suboptimal for performance reasons. */
# endif
/* We no longer exclude the main data segment. */
if ((word)end <= (word)least_ha
|| (word)start >= (word)greatest_ha) {
/* The easy case; just trace entire segment */
GC_add_roots_inner(start, end, TRUE);
continue;
}
/* Add sections that don't belong to us. */
i = 0;
while ((word)(GC_our_memory[i].hs_start
+ GC_our_memory[i].hs_bytes) < (word)start)
++i;
GC_ASSERT(i < GC_n_memory);
if ((word)GC_our_memory[i].hs_start <= (word)start) {
start = GC_our_memory[i].hs_start
+ GC_our_memory[i].hs_bytes;
++i;
}
while (i < GC_n_memory
&& (word)GC_our_memory[i].hs_start < (word)end
&& (word)start < (word)end) {
if ((word)start < (word)GC_our_memory[i].hs_start)
GC_add_roots_inner(start,
GC_our_memory[i].hs_start, TRUE);
start = GC_our_memory[i].hs_start
+ GC_our_memory[i].hs_bytes;
++i;
}
if ((word)start < (word)end)
GC_add_roots_inner(start, end, TRUE);
} else if (prot[0] == '-' && prot[1] == '-' && prot[2] == '-') {
/* Even roots added statically might disappear partially */
/* (e.g. the roots added by INCLUDE_LINUX_THREAD_DESCR). */
GC_remove_roots_subregion(start, end);
}
}
}
GC_INNER void GC_register_dynamic_libraries(void)
{
GC_register_map_entries(GC_get_maps());
}
/* We now take care of the main data segment ourselves: */
GC_INNER GC_bool GC_register_main_static_data(void)
{
return FALSE;
}
# define HAVE_REGISTER_MAIN_STATIC_DATA
#else /* !USE_PROC_FOR_LIBRARIES */
/* The following is the preferred way to walk dynamic libraries */
/* for glibc 2.2.4+. Unfortunately, it doesn't work for older */
/* versions. Thanks to Jakub Jelinek for most of the code. */
#if GC_GLIBC_PREREQ(2, 3) || defined(HOST_ANDROID)
/* Are others OK here, too? */
# ifndef HAVE_DL_ITERATE_PHDR
# define HAVE_DL_ITERATE_PHDR
# endif
# ifdef HOST_ANDROID
/* Android headers might have no such definition for some targets. */
EXTERN_C_BEGIN
extern int dl_iterate_phdr(int (*cb)(struct dl_phdr_info *,
size_t, void *),
void *data);
EXTERN_C_END
# endif
#endif /* __GLIBC__ >= 2 || HOST_ANDROID */
#if defined(__DragonFly__) || defined(__FreeBSD_kernel__) \
|| (defined(FREEBSD) && __FreeBSD__ >= 7)
/* On the FreeBSD system, any target system at major version 7 shall */
/* have dl_iterate_phdr; therefore, we need not make it weak as below. */
# ifndef HAVE_DL_ITERATE_PHDR
# define HAVE_DL_ITERATE_PHDR
# endif
# define DL_ITERATE_PHDR_STRONG
#elif defined(HAVE_DL_ITERATE_PHDR)
/* We have the header files for a glibc that includes dl_iterate_phdr.*/
/* It may still not be available in the library on the target system. */
/* Thus we also treat it as a weak symbol. */
EXTERN_C_BEGIN
# pragma weak dl_iterate_phdr
EXTERN_C_END
#endif
#if defined(HAVE_DL_ITERATE_PHDR)
# ifdef PT_GNU_RELRO
/* Instead of registering PT_LOAD sections directly, we keep them */
/* in a temporary list, and filter them by excluding PT_GNU_RELRO */
/* segments. Processing PT_GNU_RELRO sections with */
/* GC_exclude_static_roots instead would be superficially cleaner. But */
/* it runs into trouble if a client registers an overlapping segment, */
/* which unfortunately seems quite possible. */
# define MAX_LOAD_SEGS MAX_ROOT_SETS
static struct load_segment {
ptr_t start;
ptr_t end;
/* Room for a second segment if we remove a RELRO segment */
/* from the middle. */
ptr_t start2;
ptr_t end2;
} load_segs[MAX_LOAD_SEGS];
static int n_load_segs;
static GC_bool load_segs_overflow;
# endif /* PT_GNU_RELRO */
STATIC int GC_register_dynlib_callback(struct dl_phdr_info * info,
size_t size, void * ptr)
{
const ElfW(Phdr) * p;
ptr_t start, end;
int i;
/* Make sure struct dl_phdr_info is at least as big as we need. */
if (size < offsetof (struct dl_phdr_info, dlpi_phnum)
+ sizeof (info->dlpi_phnum))
return -1;
p = info->dlpi_phdr;
for (i = 0; i < (int)info->dlpi_phnum; i++, p++) {
if (p->p_type == PT_LOAD) {
GC_has_static_roots_func callback = GC_has_static_roots;
if ((p->p_flags & PF_W) == 0) continue;
start = (ptr_t)p->p_vaddr + info->dlpi_addr;
end = start + p->p_memsz;
if (callback != 0 && !callback(info->dlpi_name, start, p->p_memsz))
continue;
# ifdef PT_GNU_RELRO
# if CPP_WORDSZ == 64
/* TODO: GC_push_all eventually does the correct */
/* rounding to the next multiple of ALIGNMENT, so, most */
/* probably, we should remove the corresponding assertion */
/* check in GC_add_roots_inner along with this code line. */
/* start pointer value may require aligning. */
start = (ptr_t)((word)start & ~(word)(sizeof(word) - 1));
# endif
if (n_load_segs >= MAX_LOAD_SEGS) {
if (!load_segs_overflow) {
WARN("Too many PT_LOAD segments;"
" registering as roots directly...\n", 0);
load_segs_overflow = TRUE;
}
GC_add_roots_inner(start, end, TRUE);
} else {
load_segs[n_load_segs].start = start;
load_segs[n_load_segs].end = end;
load_segs[n_load_segs].start2 = 0;
load_segs[n_load_segs].end2 = 0;
++n_load_segs;
}
# else
GC_add_roots_inner(start, end, TRUE);
# endif /* !PT_GNU_RELRO */
}
}
# ifdef PT_GNU_RELRO
p = info->dlpi_phdr;
for (i = 0; i < (int)info->dlpi_phnum; i++, p++) {
if (p->p_type == PT_GNU_RELRO) {
/* This entry is known to be constant and will eventually be */
/* remapped as read-only. However, the address range covered */
/* by this entry is typically a subset of a previously */
/* encountered "LOAD" segment, so we need to exclude it. */
int j;
start = (ptr_t)p->p_vaddr + info->dlpi_addr;
end = start + p->p_memsz;
for (j = n_load_segs; --j >= 0; ) {
if ((word)start >= (word)load_segs[j].start
&& (word)start < (word)load_segs[j].end) {
if (load_segs[j].start2 != 0) {
WARN("More than one GNU_RELRO segment per load one\n",0);
} else {
GC_ASSERT((word)end <=
(((word)load_segs[j].end + GC_page_size - 1) &
~(GC_page_size - 1)));
/* Remove from the existing load segment */
load_segs[j].end2 = load_segs[j].end;
load_segs[j].end = start;
load_segs[j].start2 = end;
/* Note that start2 may be greater than end2 because of */
/* p->p_memsz value multiple of page size. */
}
break;
}
if (0 == j && 0 == GC_has_static_roots)
WARN("Failed to find PT_GNU_RELRO segment"
" inside PT_LOAD region\n", 0);
/* No warning reported in case of the callback is present */
/* because most likely the segment has been excluded. */
}
}
}
# endif
*(int *)ptr = 1; /* Signal that we were called */
return 0;
}
/* Do we need to separately register the main static data segment? */
GC_INNER GC_bool GC_register_main_static_data(void)
{
# ifdef DL_ITERATE_PHDR_STRONG
/* If dl_iterate_phdr is not a weak symbol then don't test against */
/* zero (otherwise a compiler might issue a warning). */
return FALSE;
# else
return 0 == COVERT_DATAFLOW(dl_iterate_phdr);
# endif
}
/* Return TRUE if we succeed, FALSE if dl_iterate_phdr wasn't there. */
STATIC GC_bool GC_register_dynamic_libraries_dl_iterate_phdr(void)
{
int did_something;
if (GC_register_main_static_data())
return FALSE;
# ifdef PT_GNU_RELRO
{
static GC_bool excluded_segs = FALSE;
n_load_segs = 0;
load_segs_overflow = FALSE;
if (!EXPECT(excluded_segs, TRUE)) {
GC_exclude_static_roots_inner((ptr_t)load_segs,
(ptr_t)load_segs + sizeof(load_segs));
excluded_segs = TRUE;
}
}
# endif
did_something = 0;
dl_iterate_phdr(GC_register_dynlib_callback, &did_something);
if (did_something) {
# ifdef PT_GNU_RELRO
int i;
for (i = 0; i < n_load_segs; ++i) {
if ((word)load_segs[i].end > (word)load_segs[i].start) {
GC_add_roots_inner(load_segs[i].start, load_segs[i].end, TRUE);
}
if ((word)load_segs[i].end2 > (word)load_segs[i].start2) {
GC_add_roots_inner(load_segs[i].start2, load_segs[i].end2, TRUE);
}
}
# endif
} else {
ptr_t datastart, dataend;
# ifdef DATASTART_IS_FUNC
static ptr_t datastart_cached = (ptr_t)GC_WORD_MAX;
/* Evaluate DATASTART only once. */
if (datastart_cached == (ptr_t)GC_WORD_MAX) {
datastart_cached = DATASTART;
}
datastart = datastart_cached;
# else
datastart = DATASTART;
# endif
# ifdef DATAEND_IS_FUNC
{
static ptr_t dataend_cached = 0;
/* Evaluate DATAEND only once. */
if (dataend_cached == 0) {
dataend_cached = DATAEND;
}
dataend = dataend_cached;
}
# else
dataend = DATAEND;
# endif
if (NULL == *(char * volatile *)&datastart
|| (word)datastart > (word)dataend)
ABORT_ARG2("Wrong DATASTART/END pair",
": %p .. %p", (void *)datastart, (void *)dataend);
/* dl_iterate_phdr may forget the static data segment in */
/* statically linked executables. */
GC_add_roots_inner(datastart, dataend, TRUE);
# ifdef GC_HAVE_DATAREGION2
if ((word)DATASTART2 - 1U >= (word)DATAEND2) {
/* Subtract one to check also for NULL */
/* without a compiler warning. */
ABORT_ARG2("Wrong DATASTART/END2 pair",
": %p .. %p", (void *)DATASTART2, (void *)DATAEND2);
}
GC_add_roots_inner(DATASTART2, DATAEND2, TRUE);
# endif
}
return TRUE;
}
# define HAVE_REGISTER_MAIN_STATIC_DATA
#else /* !HAVE_DL_ITERATE_PHDR */
/* Dynamic loading code for Linux running ELF. Somewhat tested on
* Linux/x86, untested but hopefully should work on Linux/Alpha.
* This code was derived from the Solaris/ELF support. Thanks to
* whatever kind soul wrote that. - Patrick Bridges */
/* This doesn't necessarily work in all cases, e.g. with preloaded
* dynamic libraries. */
# if defined(NETBSD) || defined(OPENBSD)
# include <sys/exec_elf.h>
/* for compatibility with 1.4.x */
# ifndef DT_DEBUG
# define DT_DEBUG 21
# endif
# ifndef PT_LOAD
# define PT_LOAD 1
# endif
# ifndef PF_W
# define PF_W 2
# endif
# elif !defined(HOST_ANDROID)
# include <elf.h>
# endif
# ifndef HOST_ANDROID
# include <link.h>
# endif
#endif /* !HAVE_DL_ITERATE_PHDR */
EXTERN_C_BEGIN
#ifdef __GNUC__
# pragma weak _DYNAMIC
#endif
extern ElfW(Dyn) _DYNAMIC[];
EXTERN_C_END
STATIC struct link_map *
GC_FirstDLOpenedLinkMap(void)
{
static struct link_map *cachedResult = 0;
if (0 == COVERT_DATAFLOW(_DYNAMIC)) {
/* _DYNAMIC symbol not resolved. */
return NULL;
}
if (NULL == cachedResult) {
# if defined(NETBSD) && defined(RTLD_DI_LINKMAP)
# if defined(CPPCHECK)
# define GC_RTLD_DI_LINKMAP 2
# else
# define GC_RTLD_DI_LINKMAP RTLD_DI_LINKMAP
# endif
struct link_map *lm = NULL;
if (!dlinfo(RTLD_SELF, GC_RTLD_DI_LINKMAP, &lm) && lm != NULL) {
/* Now lm points link_map object of libgc. Since it */
/* might not be the first dynamically linked object, */
/* try to find it (object next to the main object). */
while (lm->l_prev != NULL) {
lm = lm->l_prev;
}
cachedResult = lm->l_next;
}
# else
ElfW(Dyn) *dp;
int tag;
for( dp = _DYNAMIC; (tag = dp->d_tag) != 0; dp++ ) {
if (tag == DT_DEBUG) {
struct r_debug *rd = (struct r_debug *)dp->d_un.d_ptr;
/* d_ptr could be null if libs are linked statically. */
if (rd != NULL) {
struct link_map *lm = rd->r_map;
if (lm != NULL)
cachedResult = lm->l_next; /* might be NULL */
}
break;
}
}
# endif /* !NETBSD || !RTLD_DI_LINKMAP */
}
return cachedResult;
}
GC_INNER void GC_register_dynamic_libraries(void)
{
struct link_map *lm;
GC_ASSERT(I_HOLD_LOCK());
# ifdef HAVE_DL_ITERATE_PHDR
if (GC_register_dynamic_libraries_dl_iterate_phdr()) {
return;
}
# endif
for (lm = GC_FirstDLOpenedLinkMap(); lm != 0; lm = lm->l_next)
{
ElfW(Ehdr) * e;
ElfW(Phdr) * p;
unsigned long offset;
char * start;
int i;
e = (ElfW(Ehdr) *) lm->l_addr;
# ifdef HOST_ANDROID
if (e == NULL)
continue;
# endif
p = ((ElfW(Phdr) *)(((char *)(e)) + e->e_phoff));
offset = ((unsigned long)(lm->l_addr));
for( i = 0; i < (int)e->e_phnum; i++, p++ ) {
switch( p->p_type ) {
case PT_LOAD:
{
if( !(p->p_flags & PF_W) ) break;
start = ((char *)(p->p_vaddr)) + offset;
GC_add_roots_inner(start, start + p->p_memsz, TRUE);
}
break;
default:
break;
}
}
}
}
#endif /* !USE_PROC_FOR_LIBRARIES */
#endif /* LINUX */
#if defined(IRIX5) || (defined(USE_PROC_FOR_LIBRARIES) && !defined(LINUX))
#include <sys/procfs.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <elf.h>
#include <errno.h>
#include <signal.h> /* Only for the following test. */
#ifndef _sigargs
# define IRIX6
#endif
/* We use /proc to track down all parts of the address space that are */
/* mapped by the process, and throw out regions we know we shouldn't */
/* worry about. This may also work under other SVR4 variants. */
GC_INNER void GC_register_dynamic_libraries(void)
{
static int fd = -1;
static prmap_t * addr_map = 0;
static int current_sz = 0; /* Number of records currently in addr_map */
char buf[32];
int needed_sz = 0; /* Required size of addr_map */
int i;
long flags;
ptr_t start;
ptr_t limit;
ptr_t heap_start = HEAP_START;
ptr_t heap_end = heap_start;
# ifdef SOLARISDL
# define MA_PHYS 0
# endif /* SOLARISDL */
GC_ASSERT(I_HOLD_LOCK());
if (fd < 0) {
(void)snprintf(buf, sizeof(buf), "/proc/%ld", (long)getpid());
buf[sizeof(buf) - 1] = '\0';
fd = open(buf, O_RDONLY);
if (fd < 0) {
ABORT("/proc open failed");
}
}
if (ioctl(fd, PIOCNMAP, &needed_sz) < 0) {
ABORT_ARG2("/proc PIOCNMAP ioctl failed",
": fd= %d, errno= %d", fd, errno);
}
if (needed_sz >= current_sz) {
GC_scratch_recycle_no_gww(addr_map,
(size_t)current_sz * sizeof(prmap_t));
current_sz = needed_sz * 2 + 1;
/* Expansion, plus room for 0 record */
addr_map = (prmap_t *)GC_scratch_alloc(
(size_t)current_sz * sizeof(prmap_t));
if (addr_map == NULL)
ABORT("Insufficient memory for address map");
}
if (ioctl(fd, PIOCMAP, addr_map) < 0) {
ABORT_ARG3("/proc PIOCMAP ioctl failed",
": errcode= %d, needed_sz= %d, addr_map= %p",
errno, needed_sz, (void *)addr_map);
}
if (GC_n_heap_sects > 0) {
heap_end = GC_heap_sects[GC_n_heap_sects-1].hs_start
+ GC_heap_sects[GC_n_heap_sects-1].hs_bytes;
if ((word)heap_end < (word)GC_scratch_last_end_ptr)
heap_end = GC_scratch_last_end_ptr;
}
for (i = 0; i < needed_sz; i++) {
flags = addr_map[i].pr_mflags;
if ((flags & (MA_BREAK | MA_STACK | MA_PHYS
| MA_FETCHOP | MA_NOTCACHED)) != 0) goto irrelevant;
if ((flags & (MA_READ | MA_WRITE)) != (MA_READ | MA_WRITE))
goto irrelevant;
/* The latter test is empirically useless in very old Irix */
/* versions. Other than the */
/* main data and stack segments, everything appears to be */
/* mapped readable, writable, executable, and shared(!!). */
/* This makes no sense to me. - HB */
start = (ptr_t)(addr_map[i].pr_vaddr);
if (GC_roots_present(start)) goto irrelevant;
if ((word)start < (word)heap_end && (word)start >= (word)heap_start)
goto irrelevant;
limit = start + addr_map[i].pr_size;
/* The following seemed to be necessary for very old versions */
/* of Irix, but it has been reported to discard relevant */
/* segments under Irix 6.5. */
# ifndef IRIX6
if (addr_map[i].pr_off == 0 && strncmp(start, ELFMAG, 4) == 0) {
/* Discard text segments, i.e. 0-offset mappings against */
/* executable files which appear to have ELF headers. */
caddr_t arg;
int obj;
# define MAP_IRR_SZ 10
static ptr_t map_irr[MAP_IRR_SZ];
/* Known irrelevant map entries */
static int n_irr = 0;
struct stat buf;
int j;
for (j = 0; j < n_irr; j++) {
if (map_irr[j] == start) goto irrelevant;
}
arg = (caddr_t)start;
obj = ioctl(fd, PIOCOPENM, &arg);
if (obj >= 0) {
fstat(obj, &buf);
close(obj);
if ((buf.st_mode & 0111) != 0) {
if (n_irr < MAP_IRR_SZ) {
map_irr[n_irr++] = start;
}
goto irrelevant;
}
}
}
# endif /* !IRIX6 */
GC_add_roots_inner(start, limit, TRUE);
irrelevant: ;
}
/* Don't keep cached descriptor, for now. Some kernels don't like us */
/* to keep a /proc file descriptor around during kill -9. */
/* Otherwise, it should also require FD_CLOEXEC and proper handling */
/* at fork (i.e. close because of the pid change). */
if (close(fd) < 0) ABORT("Couldn't close /proc file");
fd = -1;
}
# endif /* USE_PROC_FOR_LIBRARIES || IRIX5 */
# if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32)
/* We traverse the entire address space and register all segments */
/* that could possibly have been written to. */
STATIC void GC_cond_add_roots(char *base, char * limit)
{
# ifdef GC_WIN32_THREADS
char * curr_base = base;
char * next_stack_lo;
char * next_stack_hi;
if (base == limit) return;
for(;;) {
GC_get_next_stack(curr_base, limit, &next_stack_lo, &next_stack_hi);
if ((word)next_stack_lo >= (word)limit) break;
if ((word)next_stack_lo > (word)curr_base)
GC_add_roots_inner(curr_base, next_stack_lo, TRUE);
curr_base = next_stack_hi;
}
if ((word)curr_base < (word)limit)
GC_add_roots_inner(curr_base, limit, TRUE);
# else
char * stack_top
= (char *)((word)GC_approx_sp() &
~(word)(GC_sysinfo.dwAllocationGranularity - 1));
if (base == limit) return;
if ((word)limit > (word)stack_top
&& (word)base < (word)GC_stackbottom) {
/* Part of the stack; ignore it. */
return;
}
GC_add_roots_inner(base, limit, TRUE);
# endif
}
#ifdef DYNAMIC_LOADING
/* GC_register_main_static_data is not needed unless DYNAMIC_LOADING. */
GC_INNER GC_bool GC_register_main_static_data(void)
{
# if defined(MSWINCE) || defined(CYGWIN32)
/* Do we need to separately register the main static data segment? */
return FALSE;
# else
return GC_no_win32_dlls;
# endif
}
# define HAVE_REGISTER_MAIN_STATIC_DATA
#endif /* DYNAMIC_LOADING */
# ifdef DEBUG_VIRTUALQUERY
void GC_dump_meminfo(MEMORY_BASIC_INFORMATION *buf)
{
GC_printf("BaseAddress= 0x%lx, AllocationBase= 0x%lx,"
" RegionSize= 0x%lx(%lu)\n",
buf -> BaseAddress, buf -> AllocationBase,
buf -> RegionSize, buf -> RegionSize);
GC_printf("\tAllocationProtect= 0x%lx, State= 0x%lx, Protect= 0x%lx, "
"Type= 0x%lx\n", buf -> AllocationProtect, buf -> State,
buf -> Protect, buf -> Type);
}
# endif /* DEBUG_VIRTUALQUERY */
# if defined(MSWINCE) || defined(CYGWIN32)
/* FIXME: Should we really need to scan MEM_PRIVATE sections? */