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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include <string.h>
/* Define _GNU_SOURCE to get RTLD_NEXT definition from dlfcn.h */
#define _GNU_SOURCE
#include <dlfcn.h>
/* Overrides will work only if RTLD_NEXT is defined */
#ifdef RTLD_NEXT
/* if we use glibc, include malloc.h for malloc_usable_size */
#ifdef __GLIBC__
#include <malloc.h>
#define HAVE_MALLOC_USABLE_SIZE
#endif
typedef int (*posix_memalign_fn)(void **memptr, size_t alignment, size_t size);
typedef void *(*realloc_fn)(void *ptr, size_t size);
posix_memalign_fn orig_posix_memalign = NULL;
realloc_fn orig_realloc = NULL;
int posix_memalign(void **memptr, size_t alignment, size_t size)
{
/* Override original posix_memalign to fill allocated memory with some data
* to catch errors due to missing initialization */
int rc;
if (orig_posix_memalign == NULL) {
/* C99 forbids converting void * to function pointers, so direct
* assignemnt fails with -pedantic. Yet dlsym is still used to return
* function pointers in standard library, despite that it returns
* void *. Casting function pointer to void ** and dereferencing it
* allows to bypass compiler warnings. */
*(void **) &orig_posix_memalign = dlsym(RTLD_NEXT, "posix_memalign");
}
rc = orig_posix_memalign(memptr, alignment, size);
memset(*memptr, 0xff, size);
return rc;
}
void *realloc(void *ptr, size_t size)
{
/* Override original realloc to fill allocated memory with some data to
* catch errors due to missing initialization */
void *p;
if (orig_realloc == NULL) {
/* C99 forbids converting void * to function pointers, so direct
* assignemnt fails with -pedantic. Yet dlsym is still used to return
* function pointers in standard library, despite that it returns
* void *. Casting function pointer to void ** and dereferencing it
* allows to bypass compiler warnings. */
*(void **) &orig_realloc = dlsym(RTLD_NEXT, "realloc");
}
#ifdef HAVE_MALLOC_USABLE_SIZE
/* If malloc_usable_size is available, we can get the size of previously
* allocated buffer, to find out how many new bytes we've allocated.
* Get the usable size for ptr before we call realloc, because realloc may call
* free() on the original pointer. */
size_t ptr_alloc_size = malloc_usable_size(ptr);
#endif
p = orig_realloc(ptr, size);
#ifdef HAVE_MALLOC_USABLE_SIZE
size_t p_alloc_size = malloc_usable_size(p);
/* If call succeeded and we're enlarging memory, fill the extension with
* non-zero data */
if (p && p_alloc_size > ptr_alloc_size) {
memset((char *) p + ptr_alloc_size, 0xff, p_alloc_size - ptr_alloc_size);
}
#else
/* If we're allocating new buffer and the call succeeded, fill the buffer
* with non-zero data*/
if (p && !ptr) {
memset(p, 0xff, size);
}
#endif
return p;
}
#endif
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