Function ptr_valid_batch

ccan/ccan/ptr_valid/ptr_valid.c:268–297

msync seems most well-defined test, but page could be mapped with * no permissions, and can't distiguish readonly from writable. */

/* msync seems most well-defined test, but page could be mapped with
 * no permissions, and can't distiguish readonly from writable. */
bool ptr_valid_batch(struct ptr_valid_batch *batch,
		     const void *p, size_t alignment, size_t size, bool write)
{
	char *start, *end;
	bool ret;

	if ((intptr_t)p & (alignment - 1))
		return false;

	start = (void *)((intptr_t)p & ~(getpagesize() - 1));
	end = (void *)(((intptr_t)p + size - 1) & ~(getpagesize() - 1));

	/* We cache single page hits. */
	if (start == end) {
		if (batch->last && batch->last == start)
			return batch->last_ok;
	}

	if (batch->num_maps)
		ret = check_with_maps(batch, p, size, write);
	else
		ret = check_with_child(batch, p, size, write);

	if (start == end) {
		batch->last = start;
		batch->last_ok = ret;
	}

	return ret;
}

bool ptr_valid_batch_string(struct ptr_valid_batch *batch, const char *p)
{