void *malloc(size_t size)
{
struct free_arena_header *fp;
if (size == 0)
return NULL;
/* Add the obligatory arena header, and round up */
size = (size + 2 * sizeof(struct arena_header) - 1) & ~ARENA_SIZE_MASK;
for (fp = __malloc_head.next_free; fp->a.type != ARENA_TYPE_HEAD;
fp = fp->next_free) {
if (fp->a.size >= size) {
/* Found fit -- allocate out of this block */
return __malloc_from_block(fp, size);
}
}
/* Nothing found... need to request a block from the kernel */
return NULL; /* No kernel to get stuff from */
}
void *malloc(size_t size)
{
struct free_arena_header *fp;
struct free_arena_header *pah;
size_t fsize;
if (size == 0)
return NULL;
/* Add the obligatory arena header, and round up */
size = (size + 2 * sizeof(struct arena_header) - 1) & ARENA_SIZE_MASK;
for (fp = __malloc_head.next_free; fp->a.type != ARENA_TYPE_HEAD;
fp = fp->next_free) {
if (fp->a.size >= size) {
/* Found fit -- allocate out of this block */
return __malloc_from_block(fp, size);
}
}
/* Nothing found... need to request a block from the kernel */
fsize = (size + MALLOC_CHUNK_MASK) & ~MALLOC_CHUNK_MASK;
#if _KLIBC_MALLOC_USES_SBRK
fp = (struct free_arena_header *)sbrk(fsize);
#else
fp = (struct free_arena_header *)
mmap(NULL, fsize, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
#endif
if (fp == (struct free_arena_header *)MAP_FAILED) {
return NULL; /* Failed to get a block */
}
/* Insert the block into the management chains. We need to set
up the size and the main block list pointer, the rest of
the work is logically identical to free(). */
fp->a.type = ARENA_TYPE_FREE;
fp->a.size = fsize;
/* We need to insert this into the main block list in the proper
place -- this list is required to be sorted. Since we most likely
get memory assignments in ascending order, search backwards for
the proper place. */
for (pah = __malloc_head.a.prev; pah->a.type != ARENA_TYPE_HEAD;
pah = pah->a.prev) {
if (pah < fp)
break;
}
/* Now pah points to the node that should be the predecessor of
the new node */
fp->a.next = pah->a.next;
fp->a.prev = pah;
pah->a.next = fp;
fp->a.next->a.prev = fp;
/* Insert into the free chain and coalesce with adjacent blocks */
fp = __free_block(fp);
/* Now we can allocate from this block */
return __malloc_from_block(fp, size);
}
