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glibc-2.41
malloc/malloc-debug.c
677 строк
20 KB
Paul Eggert
Update copyright dates with scripts/update-copyrights
01 янв 2025, 22:22
01 янв 2025, 22:22
2642002
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/* Malloc debug DSO. Copyright (C) 2021-2025 Free Software Foundation, Inc. Copyright The GNU Toolchain Authors. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; see the file COPYING.LIB. If not, see <https://www.gnu.org/licenses/>. */ #include <atomic.h> #include <libc-symbols.h> #include <shlib-compat.h> #include <string.h> #include <unistd.h> #include <sys/param.h> /* Support only the glibc allocators. */ extern void *__libc_malloc (size_t); extern void __libc_free (void *); extern void *__libc_realloc (void *, size_t); extern void *__libc_memalign (size_t, size_t); extern void *__libc_valloc (size_t); extern void *__libc_pvalloc (size_t); extern void *__libc_calloc (size_t, size_t); #define DEBUG_FN(fn) \ static __typeof (__libc_ ## fn) __debug_ ## fn DEBUG_FN(malloc); DEBUG_FN(free); DEBUG_FN(realloc); DEBUG_FN(memalign); DEBUG_FN(valloc); DEBUG_FN(pvalloc); DEBUG_FN(calloc); static int debug_initialized = -1; enum malloc_debug_hooks { MALLOC_NONE_HOOK = 0, MALLOC_MCHECK_HOOK = 1 << 0, /* mcheck() */ MALLOC_MTRACE_HOOK = 1 << 1, /* mtrace() */ MALLOC_CHECK_HOOK = 1 << 2, /* MALLOC_CHECK_ or glibc.malloc.check. */ }; static unsigned __malloc_debugging_hooks; static __always_inline bool __is_malloc_debug_enabled (enum malloc_debug_hooks flag) { return __malloc_debugging_hooks & flag; } static __always_inline void __malloc_debug_enable (enum malloc_debug_hooks flag) { __malloc_debugging_hooks |= flag; } static __always_inline void __malloc_debug_disable (enum malloc_debug_hooks flag) { __malloc_debugging_hooks &= ~flag; } #include "mcheck.c" #include "mtrace.c" #include "malloc-check.c" #if SHLIB_COMPAT (libc_malloc_debug, GLIBC_2_0, GLIBC_2_24) extern void (*__malloc_initialize_hook) (void); compat_symbol_reference (libc, __malloc_initialize_hook, __malloc_initialize_hook, GLIBC_2_0); #endif static void *malloc_hook_ini (size_t, const void *) __THROW; static void *realloc_hook_ini (void *, size_t, const void *) __THROW; static void *memalign_hook_ini (size_t, size_t, const void *) __THROW; void (*__free_hook) (void *, const void *) = NULL; void *(*__malloc_hook) (size_t, const void *) = malloc_hook_ini; void *(*__realloc_hook) (void *, size_t, const void *) = realloc_hook_ini; void *(*__memalign_hook) (size_t, size_t, const void *) = memalign_hook_ini; /* Hooks for debugging versions. The initial hooks just call the initialization routine, then do the normal work. */ /* These hooks will get executed only through the interposed allocator functions in libc_malloc_debug.so. This means that the calls to malloc, realloc, etc. will lead back into the interposed functions, which is what we want. These initial hooks are assumed to be called in a single-threaded context, so it is safe to reset all hooks at once upon initialization. */ static void generic_hook_ini (void) { debug_initialized = 0; __malloc_hook = NULL; __realloc_hook = NULL; __memalign_hook = NULL; /* malloc check does not quite co-exist with libc malloc, so initialize either on or the other. */ if (!initialize_malloc_check ()) /* The compiler does not know that these functions are allocators, so it will not try to optimize it away. */ __libc_free (__libc_malloc (0)); #if SHLIB_COMPAT (libc_malloc_debug, GLIBC_2_0, GLIBC_2_24) void (*hook) (void) = __malloc_initialize_hook; if (hook != NULL) (*hook)(); #endif debug_initialized = 1; } static void * malloc_hook_ini (size_t sz, const void *caller) { generic_hook_ini (); return __debug_malloc (sz); } static void * realloc_hook_ini (void *ptr, size_t sz, const void *caller) { generic_hook_ini (); return __debug_realloc (ptr, sz); } static void * memalign_hook_ini (size_t alignment, size_t sz, const void *caller) { generic_hook_ini (); return __debug_memalign (alignment, sz); } static size_t pagesize; /* These variables are used for undumping support. Chunked are marked as using mmap, but we leave them alone if they fall into this range. NB: The chunk size for these chunks only includes the initial size field (of SIZE_SZ bytes), there is no trailing size field (unlike with regular mmapped chunks). */ static mchunkptr dumped_main_arena_start; /* Inclusive. */ static mchunkptr dumped_main_arena_end; /* Exclusive. */ /* True if the pointer falls into the dumped arena. Use this after chunk_is_mmapped indicates a chunk is mmapped. */ #define DUMPED_MAIN_ARENA_CHUNK(p) \ ((p) >= dumped_main_arena_start && (p) < dumped_main_arena_end) /* The allocator functions. */ static void * __debug_malloc (size_t bytes) { void *(*hook) (size_t, const void *) = atomic_forced_read (__malloc_hook); if (__builtin_expect (hook != NULL, 0)) return (*hook)(bytes, RETURN_ADDRESS (0)); void *victim = NULL; size_t orig_bytes = bytes; if ((!__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK) || !malloc_mcheck_before (&bytes, &victim))) { victim = (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK) ? malloc_check (bytes) : __libc_malloc (bytes)); } if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK) && victim != NULL) victim = malloc_mcheck_after (victim, orig_bytes); if (__is_malloc_debug_enabled (MALLOC_MTRACE_HOOK)) malloc_mtrace_after (victim, orig_bytes, RETURN_ADDRESS (0)); return victim; } strong_alias (__debug_malloc, malloc) static void __debug_free (void *mem) { void (*hook) (void *, const void *) = atomic_forced_read (__free_hook); if (__builtin_expect (hook != NULL, 0)) { (*hook)(mem, RETURN_ADDRESS (0)); return; } if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK)) mem = free_mcheck (mem); if (DUMPED_MAIN_ARENA_CHUNK (mem2chunk (mem))) /* Do nothing. */; else if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK)) free_check (mem); else __libc_free (mem); if (__is_malloc_debug_enabled (MALLOC_MTRACE_HOOK)) free_mtrace (mem, RETURN_ADDRESS (0)); } strong_alias (__debug_free, free) static void * __debug_realloc (void *oldmem, size_t bytes) { void *(*hook) (void *, size_t, const void *) = atomic_forced_read (__realloc_hook); if (__builtin_expect (hook != NULL, 0)) return (*hook)(oldmem, bytes, RETURN_ADDRESS (0)); size_t orig_bytes = bytes, oldsize = 0; void *victim = NULL; if ((!__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK) || !realloc_mcheck_before (&oldmem, &bytes, &oldsize, &victim))) { mchunkptr oldp = mem2chunk (oldmem); /* If this is a faked mmapped chunk from the dumped main arena, always make a copy (and do not free the old chunk). */ if (DUMPED_MAIN_ARENA_CHUNK (oldp)) { if (bytes == 0 && oldmem != NULL) victim = NULL; else { const INTERNAL_SIZE_T osize = chunksize (oldp); /* Must alloc, copy, free. */ victim = __debug_malloc (bytes); /* Copy as many bytes as are available from the old chunk and fit into the new size. NB: The overhead for faked mmapped chunks is only SIZE_SZ, not CHUNK_HDR_SZ as for regular mmapped chunks. */ if (victim != NULL) { if (bytes > osize - SIZE_SZ) bytes = osize - SIZE_SZ; memcpy (victim, oldmem, bytes); } } } else if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK)) victim = realloc_check (oldmem, bytes); else victim = __libc_realloc (oldmem, bytes); } if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK) && victim != NULL) victim = realloc_mcheck_after (victim, oldmem, orig_bytes, oldsize); if (__is_malloc_debug_enabled (MALLOC_MTRACE_HOOK)) realloc_mtrace_after (victim, oldmem, orig_bytes, RETURN_ADDRESS (0)); return victim; } strong_alias (__debug_realloc, realloc) static void * _debug_mid_memalign (size_t alignment, size_t bytes, const void *address) { void *(*hook) (size_t, size_t, const void *) = atomic_forced_read (__memalign_hook); if (__builtin_expect (hook != NULL, 0)) return (*hook)(alignment, bytes, address); void *victim = NULL; size_t orig_bytes = bytes; if ((!__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK) || !memalign_mcheck_before (alignment, &bytes, &victim))) { victim = (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK) ? memalign_check (alignment, bytes) : __libc_memalign (alignment, bytes)); } if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK) && victim != NULL) victim = memalign_mcheck_after (victim, alignment, orig_bytes); if (__is_malloc_debug_enabled (MALLOC_MTRACE_HOOK)) memalign_mtrace_after (victim, orig_bytes, address); return victim; } static void * __debug_memalign (size_t alignment, size_t bytes) { return _debug_mid_memalign (alignment, bytes, RETURN_ADDRESS (0)); } strong_alias (__debug_memalign, memalign) static void * __debug_aligned_alloc (size_t alignment, size_t bytes) { if (!powerof2 (alignment) || alignment == 0) return NULL; return _debug_mid_memalign (alignment, bytes, RETURN_ADDRESS (0)); } strong_alias (__debug_aligned_alloc, aligned_alloc) static void * __debug_pvalloc (size_t bytes) { size_t rounded_bytes; if (!pagesize) pagesize = sysconf (_SC_PAGESIZE); /* ALIGN_UP with overflow check. */ if (__glibc_unlikely (__builtin_add_overflow (bytes, pagesize - 1, &rounded_bytes))) { errno = ENOMEM; return NULL; } rounded_bytes = rounded_bytes & -(pagesize - 1); return _debug_mid_memalign (pagesize, rounded_bytes, RETURN_ADDRESS (0)); } strong_alias (__debug_pvalloc, pvalloc) static void * __debug_valloc (size_t bytes) { if (!pagesize) pagesize = sysconf (_SC_PAGESIZE); return _debug_mid_memalign (pagesize, bytes, RETURN_ADDRESS (0)); } strong_alias (__debug_valloc, valloc) static int __debug_posix_memalign (void **memptr, size_t alignment, size_t bytes) { /* Test whether the SIZE argument is valid. It must be a power of two multiple of sizeof (void *). */ if (alignment % sizeof (void *) != 0 || !powerof2 (alignment / sizeof (void *)) || alignment == 0) return EINVAL; *memptr = _debug_mid_memalign (alignment, bytes, RETURN_ADDRESS (0)); if (*memptr == NULL) return ENOMEM; return 0; } strong_alias (__debug_posix_memalign, posix_memalign) static void * __debug_calloc (size_t nmemb, size_t size) { size_t bytes; if (__glibc_unlikely (__builtin_mul_overflow (nmemb, size, &bytes))) { errno = ENOMEM; return NULL; } void *(*hook) (size_t, const void *) = atomic_forced_read (__malloc_hook); if (__builtin_expect (hook != NULL, 0)) { void *mem = (*hook)(bytes, RETURN_ADDRESS (0)); if (mem != NULL) memset (mem, 0, bytes); return mem; } size_t orig_bytes = bytes; void *victim = NULL; if ((!__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK) || !malloc_mcheck_before (&bytes, &victim))) { victim = (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK) ? malloc_check (bytes) : __libc_malloc (bytes)); } if (victim != NULL) { if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK)) victim = malloc_mcheck_after (victim, orig_bytes); memset (victim, 0, orig_bytes); } if (__is_malloc_debug_enabled (MALLOC_MTRACE_HOOK)) malloc_mtrace_after (victim, orig_bytes, RETURN_ADDRESS (0)); return victim; } strong_alias (__debug_calloc, calloc) size_t malloc_usable_size (void *mem) { if (mem == NULL) return 0; if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK)) return mcheck_usable_size (mem); if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK)) return malloc_check_get_size (mem); mchunkptr p = mem2chunk (mem); if (DUMPED_MAIN_ARENA_CHUNK (p)) return chunksize (p) - SIZE_SZ; return musable (mem); } #define LIBC_SYMBOL(sym) libc_ ## sym #define SYMHANDLE(sym) sym ## _handle #define LOAD_SYM(sym) ({ \ static void *SYMHANDLE (sym); \ if (SYMHANDLE (sym) == NULL) \ SYMHANDLE (sym) = dlsym (RTLD_NEXT, #sym); \ SYMHANDLE (sym); \ }) int malloc_info (int options, FILE *fp) { if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK)) return __malloc_info (options, fp); int (*LIBC_SYMBOL (malloc_info)) (int, FILE *) = LOAD_SYM (malloc_info); if (LIBC_SYMBOL (malloc_info) == NULL) return -1; return LIBC_SYMBOL (malloc_info) (options, fp); } int mallopt (int param_number, int value) { if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK)) return __libc_mallopt (param_number, value); int (*LIBC_SYMBOL (mallopt)) (int, int) = LOAD_SYM (mallopt); if (LIBC_SYMBOL (mallopt) == NULL) return 0; return LIBC_SYMBOL (mallopt) (param_number, value); } void malloc_stats (void) { if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK)) return __malloc_stats (); void (*LIBC_SYMBOL (malloc_stats)) (void) = LOAD_SYM (malloc_stats); if (LIBC_SYMBOL (malloc_stats) == NULL) return; LIBC_SYMBOL (malloc_stats) (); } struct mallinfo2 mallinfo2 (void) { if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK)) return __libc_mallinfo2 (); struct mallinfo2 (*LIBC_SYMBOL (mallinfo2)) (void) = LOAD_SYM (mallinfo2); if (LIBC_SYMBOL (mallinfo2) == NULL) { struct mallinfo2 ret = {0}; return ret; } return LIBC_SYMBOL (mallinfo2) (); } struct mallinfo mallinfo (void) { if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK)) return __libc_mallinfo (); struct mallinfo (*LIBC_SYMBOL (mallinfo)) (void) = LOAD_SYM (mallinfo); if (LIBC_SYMBOL (mallinfo) == NULL) { struct mallinfo ret = {0}; return ret; } return LIBC_SYMBOL (mallinfo) (); } int malloc_trim (size_t s) { if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK)) return __malloc_trim (s); int (*LIBC_SYMBOL (malloc_trim)) (size_t) = LOAD_SYM (malloc_trim); if (LIBC_SYMBOL (malloc_trim) == NULL) return 0; return LIBC_SYMBOL (malloc_trim) (s); } #if SHLIB_COMPAT (libc_malloc_debug, GLIBC_2_0, GLIBC_2_25) /* Support for restoring dumped heaps contained in historic Emacs executables. The heap saving feature (malloc_get_state) is no longer implemented in this version of glibc, but we have a heap rewriter in malloc_set_state which transforms the heap into a version compatible with current malloc. */ #define MALLOC_STATE_MAGIC 0x444c4541l #define MALLOC_STATE_VERSION (0 * 0x100l + 5l) /* major*0x100 + minor */ struct malloc_save_state { long magic; long version; mbinptr av[NBINS * 2 + 2]; char *sbrk_base; int sbrked_mem_bytes; unsigned long trim_threshold; unsigned long top_pad; unsigned int n_mmaps_max; unsigned long mmap_threshold; int check_action; unsigned long max_sbrked_mem; unsigned long max_total_mem; /* Always 0, for backwards compatibility. */ unsigned int n_mmaps; unsigned int max_n_mmaps; unsigned long mmapped_mem; unsigned long max_mmapped_mem; int using_malloc_checking; unsigned long max_fast; unsigned long arena_test; unsigned long arena_max; unsigned long narenas; }; /* Dummy implementation which always fails. We need to provide this symbol so that existing Emacs binaries continue to work with BIND_NOW. */ void * malloc_get_state (void) { __set_errno (ENOSYS); return NULL; } compat_symbol (libc_malloc_debug, malloc_get_state, malloc_get_state, GLIBC_2_0); int malloc_set_state (void *msptr) { struct malloc_save_state *ms = (struct malloc_save_state *) msptr; if (ms->magic != MALLOC_STATE_MAGIC) return -1; /* Must fail if the major version is too high. */ if ((ms->version & ~0xffl) > (MALLOC_STATE_VERSION & ~0xffl)) return -2; if (debug_initialized == 1) return -1; bool check_was_enabled = __is_malloc_debug_enabled (MALLOC_CHECK_HOOK); /* It's not too late, so disable MALLOC_CHECK_ and all of the hooks. */ __malloc_hook = NULL; __realloc_hook = NULL; __free_hook = NULL; __memalign_hook = NULL; __malloc_debug_disable (MALLOC_CHECK_HOOK); /* We do not need to perform locking here because malloc_set_state must be called before the first call into the malloc subsystem (usually via __malloc_initialize_hook). pthread_create always calls calloc and thus must be called only afterwards, so there cannot be more than one thread when we reach this point. Also handle initialization if either we ended up being called before the first malloc or through the hook when malloc-check was enabled. */ if (debug_initialized < 0) generic_hook_ini (); else if (check_was_enabled) __libc_free (__libc_malloc (0)); /* Patch the dumped heap. We no longer try to integrate into the existing heap. Instead, we mark the existing chunks as mmapped. Together with the update to dumped_main_arena_start and dumped_main_arena_end, realloc and free will recognize these chunks as dumped fake mmapped chunks and never free them. */ /* Find the chunk with the lowest address with the heap. */ mchunkptr chunk = NULL; { size_t *candidate = (size_t *) ms->sbrk_base; size_t *end = (size_t *) (ms->sbrk_base + ms->sbrked_mem_bytes); while (candidate < end) if (*candidate != 0) { chunk = mem2chunk ((void *) (candidate + 1)); break; } else ++candidate; } if (chunk == NULL) return 0; /* Iterate over the dumped heap and patch the chunks so that they are treated as fake mmapped chunks. */ mchunkptr top = ms->av[2]; while (chunk < top) { if (inuse (chunk)) { /* Mark chunk as mmapped, to trigger the fallback path. */ size_t size = chunksize (chunk); set_head (chunk, size | IS_MMAPPED); } chunk = next_chunk (chunk); } /* The dumped fake mmapped chunks all lie in this address range. */ dumped_main_arena_start = (mchunkptr) ms->sbrk_base; dumped_main_arena_end = top; return 0; } compat_symbol (libc_malloc_debug, malloc_set_state, malloc_set_state, GLIBC_2_0); #endif /* Do not allow linking against the library. */ compat_symbol (libc_malloc_debug, aligned_alloc, aligned_alloc, GLIBC_2_16); compat_symbol (libc_malloc_debug, calloc, calloc, GLIBC_2_0); compat_symbol (libc_malloc_debug, free, free, GLIBC_2_0); compat_symbol (libc_malloc_debug, mallinfo2, mallinfo2, GLIBC_2_33); compat_symbol (libc_malloc_debug, mallinfo, mallinfo, GLIBC_2_0); compat_symbol (libc_malloc_debug, malloc_info, malloc_info, GLIBC_2_10); compat_symbol (libc_malloc_debug, malloc, malloc, GLIBC_2_0); compat_symbol (libc_malloc_debug, malloc_stats, malloc_stats, GLIBC_2_0); compat_symbol (libc_malloc_debug, malloc_trim, malloc_trim, GLIBC_2_0); compat_symbol (libc_malloc_debug, malloc_usable_size, malloc_usable_size, GLIBC_2_0); compat_symbol (libc_malloc_debug, mallopt, mallopt, GLIBC_2_0); compat_symbol (libc_malloc_debug, mcheck_check_all, mcheck_check_all, GLIBC_2_2); compat_symbol (libc_malloc_debug, mcheck, mcheck, GLIBC_2_0); compat_symbol (libc_malloc_debug, mcheck_pedantic, mcheck_pedantic, GLIBC_2_2); compat_symbol (libc_malloc_debug, memalign, memalign, GLIBC_2_0); compat_symbol (libc_malloc_debug, mprobe, mprobe, GLIBC_2_0); compat_symbol (libc_malloc_debug, mtrace, mtrace, GLIBC_2_0); compat_symbol (libc_malloc_debug, muntrace, muntrace, GLIBC_2_0); compat_symbol (libc_malloc_debug, posix_memalign, posix_memalign, GLIBC_2_2); compat_symbol (libc_malloc_debug, pvalloc, pvalloc, GLIBC_2_0); compat_symbol (libc_malloc_debug, realloc, realloc, GLIBC_2_0); compat_symbol (libc_malloc_debug, valloc, valloc, GLIBC_2_0); compat_symbol (libc_malloc_debug, __free_hook, __free_hook, GLIBC_2_0); compat_symbol (libc_malloc_debug, __malloc_hook, __malloc_hook, GLIBC_2_0); compat_symbol (libc_malloc_debug, __realloc_hook, __realloc_hook, GLIBC_2_0); compat_symbol (libc_malloc_debug, __memalign_hook, __memalign_hook, GLIBC_2_0);