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dyn_load.c
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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.
*/
/* BTL: avoid circular redefinition of dlopen if 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 */
#if defined(SOLARISDL) && defined(THREADS) && !defined(SOLARIS) \
&& !defined(CPPCHECK)
# error Fix mutual exclusion with dlopen
#endif
/* 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;
#ifdef ANY_MSWIN
/* We traverse the entire address space and register all segments */
/* that could possibly have been written to. */
STATIC void
GC_cond_add_roots(ptr_t base, ptr_t limit)
{
# ifdef THREADS
ptr_t curr_base = base;
ptr_t next_stack_lo, next_stack_hi;
# else
ptr_t stack_top;
# endif
GC_ASSERT(I_HOLD_LOCK());
if (base == limit)
return;
# ifdef THREADS
for (;;) {
GC_get_next_stack(curr_base, limit, &next_stack_lo, &next_stack_hi);
if (ADDR_GE(next_stack_lo, limit))
break;
if (ADDR_LT(curr_base, next_stack_lo))
GC_add_roots_inner(curr_base, next_stack_lo, TRUE);
curr_base = next_stack_hi;
}
if (ADDR_LT(curr_base, limit))
GC_add_roots_inner(curr_base, limit, TRUE);
# else
stack_top
= PTR_ALIGN_DOWN(GC_approx_sp(), GC_sysinfo.dwAllocationGranularity);
if (ADDR_LT(stack_top, limit) && ADDR_LT(base, GC_stackbottom)) {
/* Part of the stack; ignore it. */
return;
}
GC_add_roots_inner(base, limit, TRUE);
# endif
}
# ifdef DYNAMIC_LOADING
GC_INNER GC_bool
GC_register_main_static_data(void)
{
# if defined(MSWINCE) || defined(CYGWIN32)
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? */
/* For now, we don't add MEM_PRIVATE sections to the data roots for */
/* WinCE because otherwise SEGV fault sometimes happens to occur in */
/* GC_mark_from() (and, even if we use WRAP_MARK_SOME, WinCE prints */
/* a "Data Abort" message to the debugging console). */
/* To workaround that, use -DGC_REGISTER_MEM_PRIVATE. */
# define GC_wnt TRUE
# endif
GC_INNER void
GC_register_dynamic_libraries(void)
{
ptr_t p, base, limit;
GC_ASSERT(I_HOLD_LOCK());
# ifdef MSWIN32
if (GC_no_win32_dlls)
return;
# endif
p = (ptr_t)GC_sysinfo.lpMinimumApplicationAddress;
base = limit = p;
while (ADDR_LT(p, (ptr_t)GC_sysinfo.lpMaximumApplicationAddress)) {
MEMORY_BASIC_INFORMATION buf;
size_t result = VirtualQuery((LPVOID)p, &buf, sizeof(buf));
# ifdef MSWINCE
if (0 == result) {
if (ADDR(p) > GC_WORD_MAX - GC_sysinfo.dwAllocationGranularity)
break; /* overflow */
/* Page is free; advance to the next possible allocation base. */
p = PTR_ALIGN_UP(p + 1, GC_sysinfo.dwAllocationGranularity);
} else
# endif
/* else */ {
DWORD protect;
if (result != sizeof(buf))
ABORT("Weird VirtualQuery result");
if (ADDR(p) > GC_WORD_MAX - buf.RegionSize)
break; /* overflow */
protect = buf.Protect;
if (buf.State == MEM_COMMIT
&& (protect == PAGE_EXECUTE_READWRITE
|| protect == PAGE_EXECUTE_WRITECOPY || protect == PAGE_READWRITE
|| protect == PAGE_WRITECOPY)
&& (buf.Type == MEM_IMAGE
# ifdef GC_REGISTER_MEM_PRIVATE
|| (protect == PAGE_READWRITE && buf.Type == MEM_PRIVATE)
# else
/* There is some evidence that we cannot always */
/* ignore MEM_PRIVATE sections under Windows ME */
/* and predecessors. Hence we now also check for */
/* that case. */
|| (!GC_wnt && buf.Type == MEM_PRIVATE)
# endif
)
&& !GC_is_heap_base(buf.AllocationBase)) {
# ifdef DEBUG_VIRTUALQUERY
GC_dump_meminfo(&buf);
# endif
if (p != limit) {
GC_cond_add_roots(base, limit);
base = p;
}
limit = p + buf.RegionSize;
}
p += buf.RegionSize;
}
}
GC_cond_add_roots(base, limit);
}
#elif defined(DYNAMIC_LOADING) /* && !ANY_MSWIN */
# if !(defined(CPPCHECK) || defined(AIX) || defined(DARWIN) || defined(DGUX) \
|| defined(IRIX5) || defined(HAIKU) || defined(HPUX) || defined(HURD) \
|| defined(NACL) || defined(OSF1) || defined(SCO_ELF) \
|| defined(SERENITY) || defined(SOLARISDL) \
|| ((defined(ANY_BSD) || defined(LINUX)) && defined(__ELF__)) \
|| (defined(OPENBSD) && defined(M68K)))
# error Finding data segments of dynamic libraries is unsupported on target
# endif
# if defined(DARWIN) && !defined(USE_DYLD_TO_BIND) \
&& !defined(NO_DYLD_BIND_FULLY_IMAGE)
# include <dlfcn.h>
# endif
# ifdef SOLARISDL
# include <dlfcn.h>
# include <link.h>
# include <sys/elf.h>
# endif
# if defined(NETBSD)
# include <dlfcn.h>
# include <machine/elf_machdep.h>
# include <sys/param.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(DGUX) || defined(HURD) || defined(NACL) || defined(SCO_ELF) \
|| defined(SERENITY) \
|| ((defined(ANY_BSD) || defined(LINUX)) && defined(__ELF__))
# 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>
# endif /* HOST_ANDROID */
# if ((defined(HOST_ANDROID) && !defined(GC_DONT_DEFINE_LINK_MAP) \
&& !(__ANDROID_API__ >= 21)) \
|| defined(SERENITY)) \
&& !defined(USE_PROC_FOR_LIBRARIES)
/* 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 /* __ANDROID_API__ >= 21 || SERENITY */
# ifndef HOST_ANDROID
/* Workaround missing extern "C" around _DYNAMIC symbol in link.h */
/* of some Linux hosts. */
EXTERN_C_BEGIN
# include <link.h>
EXTERN_C_END
# endif /* !HOST_ANDROID */
# endif
/* Newer versions of GNU/Linux define this macro. We define it */
/* similarly for any ELF systems that do not. */
# 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 (0 == dynStructureAddr) {
void *startupSyms = dlopen(0, RTLD_LAZY);
dynStructureAddr = (ElfW(Dyn) *)dlsym(startupSyms, "_DYNAMIC");
/* Note: dlclose() is not called intentionally. */
}
# else
dynStructureAddr = &_DYNAMIC;
# endif
if (0 == COVERT_DATAFLOW(ADDR(dynStructureAddr))) {
/* _DYNAMIC symbol not resolved. */
return NULL;
}
if (NULL == cachedResult) {
int tag;
for (dp = (ElfW(Dyn) *)&_DYNAMIC; (tag = dp->d_tag) != 0; dp++) {
if (tag == DT_DEBUG) {
const struct r_debug *rd = (struct r_debug *)MAKE_CPTR(dp->d_un.d_ptr);
if (rd != NULL) {
const struct link_map *lm = rd->r_map;
if (lm != NULL)
cachedResult = lm->l_next; /* might be NULL */
}
break;
}
}
}
return cachedResult;
}
GC_INNER void
GC_register_dynamic_libraries(void)
{
struct link_map *lm;
GC_ASSERT(I_HOLD_LOCK());
for (lm = GC_FirstDLOpenedLinkMap(); lm != NULL; lm = lm->l_next) {
ElfW(Ehdr) * e;
ElfW(Phdr) * p;
ptr_t start;
unsigned long offset;
int i;
e = (ElfW(Ehdr) *)lm->l_addr;
p = (ElfW(Phdr) *)((ptr_t)e + e->e_phoff);
offset = (unsigned long)ADDR(e);
for (i = 0; i < (int)e->e_phnum; i++, p++) {
switch (p->p_type) {
case PT_LOAD:
if ((p->p_flags & PF_W) == 0)
break;
start = MAKE_CPTR(p->p_vaddr) + offset;
GC_add_roots_inner(start, start + p->p_memsz, TRUE);
break;
default:
break;
}
}
}
}
# endif /* SOLARISDL && !USE_PROC_FOR_LIBRARIES */
# if defined(DGUX) || defined(HURD) || defined(NACL) || defined(SCO_ELF) \
|| defined(SERENITY) \
|| ((defined(ANY_BSD) || defined(LINUX)) && defined(__ELF__))
# ifdef USE_PROC_FOR_LIBRARIES
# include <fcntl.h>
# include <string.h>
# include <sys/stat.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)
{
GC_signed_word n = (GC_signed_word)number_of_elements;
GC_signed_word nsorted = 1;
while (nsorted < n) {
GC_signed_word i;
while (nsorted < n
&& ADDR_LT(base[nsorted - 1].hs_start, base[nsorted].hs_start)) {
++nsorted;
}
if (nsorted == n)
break;
GC_ASSERT(ADDR_LT(base[nsorted].hs_start, base[nsorted - 1].hs_start));
for (i = nsorted - 1;
i >= 0 && ADDR_LT(base[i + 1].hs_start, base[i].hs_start); --i) {
struct HeapSect tmp = base[i];
base[i] = base[i + 1];
base[i + 1] = tmp;
}
GC_ASSERT(ADDR_LT(base[nsorted - 1].hs_start, base[nsorted].hs_start));
++nsorted;
}
}
STATIC void
GC_register_map_entries(const char *maps)
{
const char *prot, *path;
ptr_t my_start, my_end;
ptr_t least_ha, greatest_ha;
unsigned maj_dev;
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, &my_start, &my_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. */
# ifndef THREADS
if (ADDR_GE(GC_stackbottom, my_start)
&& ADDR_GE(my_end, GC_stackbottom)) {
/* Stack mapping; discard it. */
continue;
}
# endif
# if defined(E2K) && defined(__ptr64__)
/* TODO: avoid hard-coded addresses */
if (ADDR(my_start) == 0xc2fffffff000UL
&& ADDR(my_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(my_start, my_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 (ADDR_GE(least_ha, my_end) || ADDR_GE(my_start, greatest_ha)) {
/* The easy case; just trace the entire segment. */
GC_add_roots_inner(my_start, my_end, TRUE);
continue;
}
/* Add sections that don't belong to us. */
i = 0;
while (ADDR_LT(GC_our_memory[i].hs_start + GC_our_memory[i].hs_bytes,
my_start)) {
++i;
}
GC_ASSERT(i < GC_n_memory);
if (ADDR_GE(my_start, GC_our_memory[i].hs_start)) {
my_start = GC_our_memory[i].hs_start + GC_our_memory[i].hs_bytes;
++i;
}
for (; i < GC_n_memory && ADDR_LT(my_start, my_end)
&& ADDR_LT(GC_our_memory[i].hs_start, my_end);
++i) {
if (ADDR_LT(my_start, GC_our_memory[i].hs_start))
GC_add_roots_inner(my_start, GC_our_memory[i].hs_start, TRUE);
my_start = GC_our_memory[i].hs_start + GC_our_memory[i].hs_bytes;
}
if (ADDR_LT(my_start, my_end))
GC_add_roots_inner(my_start, my_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(my_start, my_end);
}
}
}
GC_INNER void
GC_register_dynamic_libraries(void)
{
GC_register_map_entries(GC_get_maps());
}
GC_INNER GC_bool
GC_register_main_static_data(void)
{
/* We now take care of the main data segment ourselves. */
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
# ifdef 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 my_start, my_end;
int i;
GC_ASSERT(I_HOLD_LOCK());
/* 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; /* stop */
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;
my_start = MAKE_CPTR(p->p_vaddr) + info->dlpi_addr;
my_end = my_start + p->p_memsz;
# ifdef CHERI_PURECAP
my_start = PTR_ALIGN_UP(my_start, ALIGNMENT);
my_end = PTR_ALIGN_DOWN(my_end, ALIGNMENT);
if (!SPANNING_CAPABILITY(info->dlpi_addr, ADDR(my_start), ADDR(my_end)))
continue;
my_start = cheri_bounds_set(my_start, (word)(my_end - my_start));
# endif
if (callback != 0 && !callback(info->dlpi_name, my_start, p->p_memsz))
continue;
# ifdef PT_GNU_RELRO
# if CPP_PTRSZ >= 64 && !defined(CHERI_PURECAP)
/* 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. */
/* my_start pointer value may require aligning. */
my_start = PTR_ALIGN_DOWN(my_start, ALIGNMENT);
# 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(my_start, my_end, TRUE);
} else {
load_segs[n_load_segs].start = my_start;
load_segs[n_load_segs].end = my_end;
load_segs[n_load_segs].start2 = NULL;
load_segs[n_load_segs].end2 = NULL;
++n_load_segs;
}
# else
GC_add_roots_inner(my_start, my_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;
my_start = MAKE_CPTR(p->p_vaddr) + info->dlpi_addr;
my_end = my_start + p->p_memsz;
for (j = n_load_segs; --j >= 0;) {
if (ADDR_INSIDE(my_start, load_segs[j].start, load_segs[j].end)) {
if (load_segs[j].start2 != NULL) {
WARN("More than one GNU_RELRO segment per load one\n", 0);
} else {
GC_ASSERT(
ADDR_GE(PTR_ALIGN_UP(load_segs[j].end, GC_page_size), my_end));
/* Remove from the existing load segment. */
load_segs[j].end2 = load_segs[j].end;
load_segs[j].end = my_start;
load_segs[j].start2 = my_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
/* Signal that we were called. */
*(int *)ptr = 1;
return 0;
}
GC_INNER GC_bool
GC_register_main_static_data(void)
{
# if defined(DL_ITERATE_PHDR_STRONG) && !defined(CPPCHECK)
/* 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(ADDR(dl_iterate_phdr));
# endif
}
# define HAVE_REGISTER_MAIN_STATIC_DATA
/* 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;
GC_ASSERT(I_HOLD_LOCK());
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 (ADDR_LT(load_segs[i].start, load_segs[i].end))
GC_add_roots_inner(load_segs[i].start, load_segs[i].end, TRUE);
if (ADDR_LT(load_segs[i].start2, load_segs[i].end2))
GC_add_roots_inner(load_segs[i].start2, load_segs[i].end2, TRUE);
}
# endif
} else {
ptr_t datastart, dataend;
# ifdef DATASTART_USES_XGETDATASTART
static ptr_t datastart_cached = MAKE_CPTR(GC_WORD_MAX);
/* Evaluate DATASTART only once. */
if (ADDR(datastart_cached) == 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 || ADDR_LT(dataend, datastart))
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
/* Subtract one to check also for NULL without a compiler warning. */
if (ADDR(DATASTART2) - 1U >= ADDR(DATAEND2)) {
ABORT_ARG2("Wrong DATASTART/END2 pair", ": %p .. %p", (void *)DATASTART2,
(void *)DATAEND2);
}
GC_add_roots_inner(DATASTART2, DATAEND2, TRUE);
# endif
}
return TRUE;
}
# else /* !HAVE_DL_ITERATE_PHDR */
/* Dynamic loading code for Linux running ELF. Somewhat tested on */
/* Linux/i686, 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 does not 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(ADDR(_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) {
const struct r_debug *rd = (struct r_debug *)MAKE_CPTR(dp->d_un.d_ptr);
/* d_ptr could be 0 if libs are linked statically. */
if (rd != NULL) {
const struct link_map *lm = rd->r_map;
# if defined(CPPCHECK) \
&& ((defined(HOST_ANDROID) && !defined(GC_DONT_DEFINE_LINK_MAP) \
&& !(__ANDROID_API__ >= 21)) \
|| defined(SERENITY))
GC_noop1((word)rd->r_version);
# endif
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 != NULL; lm = lm->l_next) {
ElfW(Ehdr) * e;
ElfW(Phdr) * p;
ptr_t start;
unsigned long offset;
int i;
e = (ElfW(Ehdr) *)lm->l_addr;
# ifdef HOST_ANDROID
if (NULL == e)
continue;
# endif
p = (ElfW(Phdr) *)((ptr_t)e + e->e_phoff);
offset = (unsigned long)ADDR(e);
for (i = 0; i < (int)e->e_phnum; i++, p++) {
switch (p->p_type) {
case PT_LOAD:
if ((p->p_flags & PF_W) == 0)
break;
start = MAKE_CPTR(p->p_vaddr) + offset;
GC_add_roots_inner(start, start + p->p_memsz, TRUE);
break;
default:
break;
}
}
# if defined(CPPCHECK) \
&& ((defined(HOST_ANDROID) && !defined(GC_DONT_DEFINE_LINK_MAP) \
&& !(__ANDROID_API__ >= 21)) \
|| defined(SERENITY))
GC_noop1_ptr(lm->l_name);
GC_noop1((word)lm->l_ld);
GC_noop1_ptr(lm->l_prev);
# endif
}
}
# endif /* !USE_PROC_FOR_LIBRARIES */
# endif /* DGUX || HURD || NACL || (ANY_BSD || LINUX) && __ELF__ */
# if defined(USE_PROC_FOR_LIBRARIES) && !defined(LINUX) || defined(IRIX5)
# include <elf.h>
# include <errno.h>
# include <fcntl.h>
# include <sys/procfs.h>
# include <sys/stat.h>
/* This is included only for the following test. */
# include <signal.h>
# 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;
/* Number of records currently in addr_map. */
static int current_sz = 0;
char buf[32];
/* Required size of addr_map. */
int needed_sz = 0;
int i;
long flags;
ptr_t start;
ptr_t limit;
word heap_start = ADDR(HEAP_START);
word heap_end = heap_start;
# ifdef SOLARISDL
# define MA_PHYS 0
# endif
GC_ASSERT(I_HOLD_LOCK());