diff options
Diffstat (limited to 'malloc/mcheck.c')
| -rw-r--r-- | malloc/mcheck.c | 398 |
1 files changed, 21 insertions, 377 deletions
diff --git a/malloc/mcheck.c b/malloc/mcheck.c index 1e68cedbf5..74c20ffe25 100644 --- a/malloc/mcheck.c +++ b/malloc/mcheck.c @@ -1,4 +1,4 @@ -/* Standard debugging hooks for `malloc'. +/* The mcheck() interface. Copyright (C) 1990-2021 Free Software Foundation, Inc. This file is part of the GNU C Library. Written May 1989 by Mike Haertel. @@ -17,402 +17,46 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ -#ifndef _MALLOC_INTERNAL -# define _MALLOC_INTERNAL -# include <malloc.h> -# include <malloc-size.h> -# include <mcheck.h> -# include <stdint.h> -# include <stdio.h> -# include <libintl.h> -# include <errno.h> -# include <malloc-internal.h> -#endif - -/* Old hook values. */ -static void (*old_free_hook)(void *ptr, const void *); -static void *(*old_malloc_hook) (size_t size, const void *); -static void *(*old_memalign_hook) (size_t alignment, size_t size, - const void *); -static void *(*old_realloc_hook) (void *ptr, size_t size, - const void *); - -/* Function to call when something awful happens. */ -static void (*abortfunc) (enum mcheck_status); - -/* Arbitrary magical numbers. */ -#define MAGICWORD 0xfedabeeb -#define MAGICFREE 0xd8675309 -#define MAGICBYTE ((char) 0xd7) -#define MALLOCFLOOD ((char) 0x93) -#define FREEFLOOD ((char) 0x95) - -struct hdr -{ - size_t size; /* Exact size requested by user. */ - unsigned long int magic; /* Magic number to check header integrity. */ - struct hdr *prev; - struct hdr *next; - void *block; /* Real block allocated, for memalign. */ - unsigned long int magic2; /* Extra, keeps us doubleword aligned. */ -} __attribute__ ((aligned (MALLOC_ALIGNMENT))); - -/* This is the beginning of the list of all memory blocks allocated. - It is only constructed if the pedantic testing is requested. */ -static struct hdr *root; - -static int mcheck_used; - -/* Nonzero if pedentic checking of all blocks is requested. */ -static int pedantic; - -#if defined _LIBC || defined STDC_HEADERS || defined USG -# include <string.h> -# define flood memset +#if !IS_IN (libc) +# include "mcheck-impl.c" #else -static void flood (void *, int, size_t); -static void -flood (void *ptr, int val, size_t size) -{ - char *cp = ptr; - while (size--) - *cp++ = val; -} +# include <mcheck.h> #endif -static enum mcheck_status -checkhdr (const struct hdr *hdr) -{ - enum mcheck_status status; - - if (!mcheck_used) - /* Maybe the mcheck used is disabled? This happens when we find - an error and report it. */ - return MCHECK_OK; - - switch (hdr->magic ^ ((uintptr_t) hdr->prev + (uintptr_t) hdr->next)) - { - default: - status = MCHECK_HEAD; - break; - case MAGICFREE: - status = MCHECK_FREE; - break; - case MAGICWORD: - if (((char *) &hdr[1])[hdr->size] != MAGICBYTE) - status = MCHECK_TAIL; - else if ((hdr->magic2 ^ (uintptr_t) hdr->block) != MAGICWORD) - status = MCHECK_HEAD; - else - status = MCHECK_OK; - break; - } - if (status != MCHECK_OK) - { - mcheck_used = 0; - (*abortfunc) (status); - mcheck_used = 1; - } - return status; -} - void mcheck_check_all (void) { - /* Walk through all the active blocks and test whether they were tampered - with. */ - struct hdr *runp = root; - - /* Temporarily turn off the checks. */ - pedantic = 0; - - while (runp != NULL) - { - (void) checkhdr (runp); - - runp = runp->next; - } - - /* Turn checks on again. */ - pedantic = 1; -} -#ifdef _LIBC -libc_hidden_def (mcheck_check_all) +#if !IS_IN (libc) + __mcheck_checkptr (NULL); #endif - -static void -unlink_blk (struct hdr *ptr) -{ - if (ptr->next != NULL) - { - ptr->next->prev = ptr->prev; - ptr->next->magic = MAGICWORD ^ ((uintptr_t) ptr->next->prev - + (uintptr_t) ptr->next->next); - } - if (ptr->prev != NULL) - { - ptr->prev->next = ptr->next; - ptr->prev->magic = MAGICWORD ^ ((uintptr_t) ptr->prev->prev - + (uintptr_t) ptr->prev->next); - } - else - root = ptr->next; -} - -static void -link_blk (struct hdr *hdr) -{ - hdr->prev = NULL; - hdr->next = root; - root = hdr; - hdr->magic = MAGICWORD ^ (uintptr_t) hdr->next; - - /* And the next block. */ - if (hdr->next != NULL) - { - hdr->next->prev = hdr; - hdr->next->magic = MAGICWORD ^ ((uintptr_t) hdr - + (uintptr_t) hdr->next->next); - } } -static void -freehook (void *ptr, const void *caller) -{ - if (pedantic) - mcheck_check_all (); - if (ptr) - { - struct hdr *hdr = ((struct hdr *) ptr) - 1; - checkhdr (hdr); - hdr->magic = MAGICFREE; - hdr->magic2 = MAGICFREE; - unlink_blk (hdr); - hdr->prev = hdr->next = NULL; - flood (ptr, FREEFLOOD, hdr->size); - ptr = hdr->block; - } - __free_hook = old_free_hook; - if (old_free_hook != NULL) - (*old_free_hook)(ptr, caller); - else - free (ptr); - __free_hook = freehook; -} - -static void * -mallochook (size_t size, const void *caller) -{ - struct hdr *hdr; - - if (pedantic) - mcheck_check_all (); - - if (size > ~((size_t) 0) - (sizeof (struct hdr) + 1)) - { - __set_errno (ENOMEM); - return NULL; - } - - __malloc_hook = old_malloc_hook; - if (old_malloc_hook != NULL) - hdr = (struct hdr *) (*old_malloc_hook)(sizeof (struct hdr) + size + 1, - caller); - else - hdr = (struct hdr *) malloc (sizeof (struct hdr) + size + 1); - __malloc_hook = mallochook; - if (hdr == NULL) - return NULL; - - hdr->size = size; - link_blk (hdr); - hdr->block = hdr; - hdr->magic2 = (uintptr_t) hdr ^ MAGICWORD; - ((char *) &hdr[1])[size] = MAGICBYTE; - flood ((void *) (hdr + 1), MALLOCFLOOD, size); - return (void *) (hdr + 1); -} - -static void * -memalignhook (size_t alignment, size_t size, - const void *caller) -{ - struct hdr *hdr; - size_t slop; - char *block; - - if (pedantic) - mcheck_check_all (); - - slop = (sizeof *hdr + alignment - 1) & - alignment; - - if (size > ~((size_t) 0) - (slop + 1)) - { - __set_errno (ENOMEM); - return NULL; - } - - __memalign_hook = old_memalign_hook; - if (old_memalign_hook != NULL) - block = (*old_memalign_hook)(alignment, slop + size + 1, caller); - else - block = memalign (alignment, slop + size + 1); - __memalign_hook = memalignhook; - if (block == NULL) - return NULL; - - hdr = ((struct hdr *) (block + slop)) - 1; - - hdr->size = size; - link_blk (hdr); - hdr->block = (void *) block; - hdr->magic2 = (uintptr_t) block ^ MAGICWORD; - ((char *) &hdr[1])[size] = MAGICBYTE; - flood ((void *) (hdr + 1), MALLOCFLOOD, size); - return (void *) (hdr + 1); -} - -static void * -reallochook (void *ptr, size_t size, const void *caller) -{ - if (size == 0) - { - freehook (ptr, caller); - return NULL; - } - - struct hdr *hdr; - size_t osize; - - if (pedantic) - mcheck_check_all (); - - if (size > ~((size_t) 0) - (sizeof (struct hdr) + 1)) - { - __set_errno (ENOMEM); - return NULL; - } - - if (ptr) - { - hdr = ((struct hdr *) ptr) - 1; - osize = hdr->size; - - checkhdr (hdr); - unlink_blk (hdr); - if (size < osize) - flood ((char *) ptr + size, FREEFLOOD, osize - size); - } - else - { - osize = 0; - hdr = NULL; - } - __free_hook = old_free_hook; - __malloc_hook = old_malloc_hook; - __memalign_hook = old_memalign_hook; - __realloc_hook = old_realloc_hook; - if (old_realloc_hook != NULL) - hdr = (struct hdr *) (*old_realloc_hook)((void *) hdr, - sizeof (struct hdr) + size + 1, - caller); - else - hdr = (struct hdr *) realloc ((void *) hdr, - sizeof (struct hdr) + size + 1); - __free_hook = freehook; - __malloc_hook = mallochook; - __memalign_hook = memalignhook; - __realloc_hook = reallochook; - if (hdr == NULL) - return NULL; - - hdr->size = size; - link_blk (hdr); - hdr->block = hdr; - hdr->magic2 = (uintptr_t) hdr ^ MAGICWORD; - ((char *) &hdr[1])[size] = MAGICBYTE; - if (size > osize) - flood ((char *) (hdr + 1) + osize, MALLOCFLOOD, size - osize); - return (void *) (hdr + 1); -} - -__attribute__ ((noreturn)) -static void -mabort (enum mcheck_status status) -{ - const char *msg; - switch (status) - { - case MCHECK_OK: - msg = _ ("memory is consistent, library is buggy\n"); - break; - case MCHECK_HEAD: - msg = _ ("memory clobbered before allocated block\n"); - break; - case MCHECK_TAIL: - msg = _ ("memory clobbered past end of allocated block\n"); - break; - case MCHECK_FREE: - msg = _ ("block freed twice\n"); - break; - default: - msg = _ ("bogus mcheck_status, library is buggy\n"); - break; - } -#ifdef _LIBC - __libc_fatal (msg); -#else - fprintf (stderr, "mcheck: %s", msg); - fflush (stderr); - abort (); -#endif -} - -/* Memory barrier so that GCC does not optimize out the argument. */ -#define malloc_opt_barrier(x) \ - ({ __typeof (x) __x = x; __asm ("" : "+m" (__x)); __x; }) int mcheck (void (*func) (enum mcheck_status)) { - abortfunc = (func != NULL) ? func : &mabort; - - /* These hooks may not be safely inserted if malloc is already in use. */ - if (__malloc_initialized <= 0 && !mcheck_used) - { - /* We call malloc() once here to ensure it is initialized. */ - void *p = malloc (0); - /* GCC might optimize out the malloc/free pair without a barrier. */ - p = malloc_opt_barrier (p); - free (p); - - old_free_hook = __free_hook; - __free_hook = freehook; - old_malloc_hook = __malloc_hook; - __malloc_hook = mallochook; - old_memalign_hook = __memalign_hook; - __memalign_hook = memalignhook; - old_realloc_hook = __realloc_hook; - __realloc_hook = reallochook; - mcheck_used = 1; - } - - return mcheck_used ? 0 : -1; -} -#ifdef _LIBC -libc_hidden_def (mcheck) +#if IS_IN (libc) + return -1; +#else + return __mcheck_initialize (func, false); #endif +} int mcheck_pedantic (void (*func) (enum mcheck_status)) { - int res = mcheck (func); - if (res == 0) - pedantic = 1; - return res; +#if IS_IN (libc) + return -1; +#else + return __mcheck_initialize (func, true); +#endif } enum mcheck_status mprobe (void *ptr) { - return mcheck_used ? checkhdr (((struct hdr *) ptr) - 1) : MCHECK_DISABLED; +#if IS_IN (libc) + return MCHECK_DISABLED; +#else + return __mcheck_checkptr (ptr); +#endif } |