Function realloc

payloads/libpayload/libc/malloc.c:310–356

}

void *realloc(void *ptr, size_t size)
{
	void *ret, *pptr;
	hdrtype_t volatile *block;
	unsigned int osize;
	struct memory_type *type = heap;

	if (ptr == NULL)
		return alloc(size, type);

	pptr = ptr - HDRSIZE;

	if (!HAS_MAGIC(*((hdrtype_t *) pptr)))
		return NULL;

	if (ptr < type->start || ptr >= type->end)
		type = dma;

	/* Get the original size of the block. */
	osize = SIZE(*((hdrtype_t *) pptr));

	/*
	 * Free the memory to update the tables - this won't touch the actual
	 * memory, so we can still use it for the copy after we have
	 * reallocated the new space.
	 */
	free(ptr);

	block = find_free_block(size, type);
	if (block == NULL)
		return NULL;

	ret = (void *)((uintptr_t)block + HDRSIZE);

	/*
	 * If ret == ptr, then no copy is needed. Otherwise, move the memory to
	 * the new location, which might be before the old one and overlap since
	 * the free() above includes a _consolidate().
	 */
	if (ret != ptr)
		memmove(ret, ptr, osize > size ? size : osize);

	/* Mark the block as used. */
	use_block(block, size);

	return ret;
}

struct align_region_t
{