C++ (Cpp) is_shm_queue_valid示例

示例#1

文件： local.c 项目： Nexenta/sheepdog

static void shm_queue_init(void)
{
	int ret;

	shmfd = open(shmfile, O_CREAT | O_RDWR, 0644);
	if (shmfd < 0)
		panic("cannot open shared file, %s\n", shmfile);

	shm_queue_lock();

	ret = ftruncate(shmfd, sizeof(*shm_queue));
	assert(ret == 0);

	shm_queue = mmap(0, sizeof(*shm_queue),
			 PROT_READ | PROT_WRITE, MAP_SHARED, shmfd, 0);
	assert(shm_queue != MAP_FAILED);

	if (is_shm_queue_valid())
		event_pos = shm_queue->pos;
	else {
		/* initialize shared memory */
		event_pos = 0;
		ret = ftruncate(shmfd, 0);
		assert(ret == 0);
		ret = ftruncate(shmfd, sizeof(*shm_queue));
		assert(ret == 0);

		shm_queue_set_chksum();
	}

	shm_queue_unlock();
}

示例#2

文件： local.c 项目： sglwlb/sheepdog

static void shm_queue_init(void)
{
	int ret;

	shmfd = open(shmfile, O_CREAT | O_RDWR, 0644);
	if (shmfd < 0)
		panic("cannot open shared file, %s", shmfile);

	shm_queue_lock();

	ret = xftruncate(shmfd, sizeof(*shm_queue));
	if (ret != 0)
		panic("failed to truncate shmfile, %m");

	shm_queue = mmap(NULL, sizeof(*shm_queue),
			 PROT_READ | PROT_WRITE, MAP_SHARED, shmfd, 0);
	if (shm_queue == MAP_FAILED)
		panic("mmap error, %m");

	if (is_shm_queue_valid()) {
		block_event_pos = shm_queue->block_event_pos;
		nonblock_event_pos = shm_queue->nonblock_event_pos;
	} else {
		/* initialize shared memory */
		block_event_pos = 0;
		nonblock_event_pos = 0;
		ret = xftruncate(shmfd, 0);
		if (ret != 0)
			panic("failed to truncate shmfile, %m");
		ret = xftruncate(shmfd, sizeof(*shm_queue));
		if (ret != 0)
			panic("failed to truncate shmfile, %m");
	}

	shm_queue_unlock();
}