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/* alloc.c
*
* Written by Erik Andersen <andersee@codepoet.org>
* LGPLv2
*
* Parts of the memalign code were stolen from malloc-930716.
*/
#define _GNU_SOURCE
#include <features.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/mman.h>
#ifdef L_malloc
void *malloc(size_t size)
{
void *result;
if (unlikely(size == 0)) {
#if defined(__MALLOC_GLIBC_COMPAT__)
size++;
#else
/* Some programs will call malloc (0). Lets be strict and return NULL */
return 0;
#endif
}
#ifdef __ARCH_HAS_MMU__
#define MMAP_FLAGS MAP_PRIVATE | MAP_ANONYMOUS
#else
#define MMAP_FLAGS MAP_SHARED | MAP_ANONYMOUS
#endif
result = mmap((void *) 0, size + sizeof(size_t), PROT_READ | PROT_WRITE,
MMAP_FLAGS, 0, 0);
if (result == MAP_FAILED)
return 0;
* (size_t *) result = size;
return(result + sizeof(size_t));
}
#endif
#ifdef L_calloc
void * calloc(size_t nmemb, size_t lsize)
{
void *result;
size_t size=lsize * nmemb;
/* guard vs integer overflow, but allow nmemb
* to fall through and call malloc(0) */
if (nmemb && lsize != (size / nmemb)) {
__set_errno(ENOMEM);
return NULL;
}
result=malloc(size);
#if 0
/* Standard unix mmap using /dev/zero clears memory so calloc
* doesn't need to actually zero anything....
*/
if (result != NULL) {
memset(result, 0, size);
}
#endif
return result;
}
#endif
#ifdef L_realloc
void *realloc(void *ptr, size_t size)
{
void *newptr = NULL;
if (!ptr)
return malloc(size);
if (!size) {
free(ptr);
return malloc(0);
}
newptr = malloc(size);
if (newptr) {
memcpy(newptr, ptr,
*((size_t *) (ptr - sizeof(size_t)))
);
free(ptr);
}
return newptr;
}
#endif
#ifdef L_free
extern int weak_function __libc_free_aligned(void *ptr);
void free(void *ptr)
{
if (ptr == NULL)
return;
if (unlikely(__libc_free_aligned!=NULL)) {
if (__libc_free_aligned(ptr)) {
return;
}
}
ptr -= sizeof(size_t);
munmap(ptr, * (size_t *) ptr + sizeof(size_t));
}
#endif
#ifdef L_memalign
#ifdef __UCLIBC_HAS_THREADS__
#include <pthread.h>
pthread_mutex_t __malloc_lock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
# define LOCK __pthread_mutex_lock(&__malloc_lock)
# define UNLOCK __pthread_mutex_unlock(&__malloc_lock);
#else
# define LOCK
# define UNLOCK
#endif
/* List of blocks allocated with memalign or valloc */
struct alignlist
{
struct alignlist *next;
__ptr_t aligned; /* The address that memaligned returned. */
__ptr_t exact; /* The address that malloc returned. */
};
struct alignlist *_aligned_blocks;
/* Return memory to the heap. */
int __libc_free_aligned(void *ptr)
{
struct alignlist *l;
if (ptr == NULL)
return 0;
LOCK;
for (l = _aligned_blocks; l != NULL; l = l->next) {
if (l->aligned == ptr) {
/* Mark the block as free */
l->aligned = NULL;
ptr = l->exact;
ptr -= sizeof(size_t);
munmap(ptr, * (size_t *) ptr + sizeof(size_t));
return 1;
}
}
UNLOCK;
return 0;
}
void * memalign (size_t alignment, size_t size)
{
void * result;
unsigned long int adj;
result = malloc (size + alignment - 1);
if (result == NULL)
return NULL;
adj = (unsigned long int) ((unsigned long int) ((char *) result -
(char *) NULL)) % alignment;
if (adj != 0)
{
struct alignlist *l;
LOCK;
for (l = _aligned_blocks; l != NULL; l = l->next)
if (l->aligned == NULL)
/* This slot is free. Use it. */
break;
if (l == NULL)
{
l = (struct alignlist *) malloc (sizeof (struct alignlist));
if (l == NULL) {
free(result);
UNLOCK;
return NULL;
}
l->next = _aligned_blocks;
_aligned_blocks = l;
}
l->exact = result;
result = l->aligned = (char *) result + alignment - adj;
UNLOCK;
}
return result;
}
#endif
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