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/*
* Copyright (c) 2012, 2013 ARM Ltd
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the company may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "local-malloc.h"
/* List list header of free blocks */
chunk_t *__malloc_free_list;
/* Starting point of memory allocated from system */
char *__malloc_sbrk_start;
char *__malloc_sbrk_top;
/*
* Algorithm:
* Use sbrk() to obtain more memory and ensure the storage is
* MALLOC_CHUNK_ALIGN aligned. Optimise for the case that it is
* already aligned - only ask for extra padding after we know we
* need it
*/
static void *
__malloc_sbrk_aligned(size_t s)
{
char *p, *align_p;
#ifdef __APPLE__
/* Mac OS X 'emulates' sbrk, but the
* parameter is int, not intptr_t or ptrdiff_t,
*/
int d = (int)s;
if (d < 0 || (size_t)d != s)
return (void *)-1;
#else
intptr_t d = (intptr_t)s;
if (d < 0)
return (void *)-1;
#endif
p = sbrk(d);
/* sbrk returns -1 if fail to allocate */
if (p == (void *)-1)
return p;
__malloc_sbrk_top = (char *)((uintptr_t)p + s);
/* Adjust returned space so that the storage area
* is MALLOC_CHUNK_ALIGN aligned and the head is
* MALLOC_HEAD_ALIGN aligned.
*/
align_p = (char *)(__align_up((uintptr_t)p + MALLOC_HEAD, MALLOC_CHUNK_ALIGN) - MALLOC_HEAD);
if (align_p != p) {
/* p is not aligned, ask for a few more bytes so that we have
* s bytes reserved from align_p. This should only occur for
* the first sbrk in a chunk of memory as all others should be
* aligned to the right value as chunk sizes are selected to
* make them abut in memory
*/
intptr_t adjust = align_p - p;
char *extra = sbrk(adjust);
if (extra != (char *)((uintptr_t)p + s))
return (void *)-1;
__malloc_sbrk_top = extra + adjust;
}
if (__malloc_sbrk_start == NULL)
__malloc_sbrk_start = align_p;
return align_p;
}
bool
__malloc_grow_chunk(chunk_t *c, size_t new_size)
{
char *chunk_e = chunk_end(c);
if (chunk_e != __malloc_sbrk_top)
return false;
size_t add_size = MAX(MALLOC_MINSIZE, new_size - _size(c));
/* Ask for the extra memory needed */
char *heap = __malloc_sbrk_aligned(add_size);
/* Check if we got what we wanted */
if (heap == chunk_e) {
/* Set size and return */
*_size_ref(c) += add_size;
return true;
}
if (heap != (char *)-1) {
/* sbrk returned unexpected memory, free it */
make_free_chunk((chunk_t *)(heap + MALLOC_HEAD), add_size);
}
return false;
}
/** Function malloc
* Algorithm:
* Walk through the free list to find the first match. If fails to find
* one, call sbrk to allocate a new chunk_t.
*/
void *
malloc(size_t s)
{
chunk_t **p, *r;
char *ptr;
size_t alloc_size;
if (s > MALLOC_MAXSIZE) {
errno = ENOMEM;
return NULL;
}
alloc_size = chunk_size(s);
MALLOC_LOCK;
for (p = &__malloc_free_list; (r = *p) != NULL; p = &r->next) {
if (_size(r) >= alloc_size) {
size_t rem = _size(r) - alloc_size;
if (rem >= MALLOC_MINSIZE) {
/* Find a chunk_t that much larger than required size, break
* it into two chunks and return the first one
*/
chunk_t *s = (chunk_t *)((char *)r + alloc_size);
_set_size(s, rem);
s->next = r->next;
*p = s;
_set_size(r, alloc_size);
} else {
/* Find a chunk_t that is exactly the size or slightly bigger
* than requested size, just return this chunk_t
*/
*p = r->next;
}
break;
}
if (!r->next && __malloc_grow_chunk(r, alloc_size)) {
/* Grow the last chunk in memory to the requested size,
* just return it
*/
*p = r->next;
break;
}
}
/* Failed to find a appropriate chunk_t. Ask for more memory */
if (r == NULL) {
void *blob = __malloc_sbrk_aligned(alloc_size);
/* sbrk returns -1 if fail to allocate */
if (blob == (void *)-1) {
errno = ENOMEM;
MALLOC_UNLOCK;
return NULL;
}
r = blob_to_chunk(blob);
_set_size(r, alloc_size);
}
MALLOC_UNLOCK;
ptr = chunk_to_ptr(r);
memset(ptr, '\0', alloc_size - MALLOC_HEAD);
return ptr;
}
#ifdef __strong_reference
#if defined(__GNUCLIKE_PRAGMA_DIAGNOSTIC) && !defined(__clang__)
#pragma GCC diagnostic ignored "-Wmissing-attributes"
#endif
__strong_reference(malloc, __malloc_malloc);
#endif
#if MALLOC_DEBUG
#include <assert.h>
void
__malloc_validate_block(chunk_t *r)
{
assert(__align_up(chunk_to_ptr(r), MALLOC_CHUNK_ALIGN) == chunk_to_ptr(r));
assert(__align_up(r, MALLOC_HEAD_ALIGN) == r);
assert(_size(r) >= MALLOC_MINSIZE);
assert(_size(r) < 0x80000000UL);
assert(__align_up(_size(r), MALLOC_HEAD_ALIGN) == _size(r));
}
void
__malloc_validate(void)
{
chunk_t *r;
for (r = __malloc_free_list; r; r = r->next) {
__malloc_validate_block(r);
assert(r->next == NULL || (char *)r + _size(r) <= (char *)r->next);
}
}
#endif