C++ (Cpp) tap_ctl_read_message示例

示例#1

文件： tap-ctl-ipc.c 项目： MarkSymsCtx/blktap

int
tap_ctl_send_and_receive_with_logpath(int sfd, tapdisk_message_t *message,
			 const char *logpath, struct timeval *timeout)
{
	int err, ret;

	err = tap_ctl_write_message(sfd, message, timeout);
	if (err) {
		EPRINTF("failed to send '%s' message\n",
			tapdisk_message_name(message->type));
		return err;
	}

	char buf[TAPDISK_MESSAGE_MAX_PATH_LENGTH];

	snprintf(buf, TAPDISK_MESSAGE_MAX_PATH_LENGTH - 1, "%s", logpath);  

	ret = write(sfd, &buf, sizeof(buf));

	if (ret == -1) {
		EPRINTF("Failed to send logpath with '%s' message\n",
			tapdisk_message_name(message->type));
	}	

	err = tap_ctl_read_message(sfd, message, timeout);
	if (err) {
		EPRINTF("failed to receive '%s' message\n",
			tapdisk_message_name(message->type));
		return err;
	}

	return 0;
}

示例#2

文件： tap-ctl-stats.c 项目： DarumasLegs/blktap

int
_tap_ctl_stats_connect_and_send(pid_t pid, int minor)
{
	struct timeval timeout = { .tv_sec = 10, .tv_usec = 0 };
	tapdisk_message_t message;
	int sfd, err;

	err = tap_ctl_connect_id(pid, &sfd);
	if (err)
		return err;

	memset(&message, 0, sizeof(message));
	message.type   = TAPDISK_MESSAGE_STATS;
	message.cookie = minor;

	err = tap_ctl_write_message(sfd, &message, &timeout);
	if (err)
		return err;

	return sfd;
}

ssize_t
tap_ctl_stats(pid_t pid, int minor, char *buf, size_t size)
{
	tapdisk_message_t message;
	int sfd, err;
	size_t len;

	sfd = _tap_ctl_stats_connect_and_send(pid, minor);
	if (sfd < 0)
		return sfd;

	err = tap_ctl_read_message(sfd, &message, NULL);
	if (err)
		return err;

	len= message.u.info.length;
	if (len < 0) {
		err = len;
		goto out;
	}
	if (size < len + 1)
		len = size - 1;

	err = tap_ctl_read_raw(sfd, buf, len, NULL);
	if (err)
		goto out;

	buf[len] = 0;

out:
	close(sfd);
	return err;
}

示例#3

文件： tap-ctl-ipc.c 项目： majieyue/blktap3

int
tap_ctl_send_and_receive(int sfd, tapdisk_message_t * message,
                         struct timeval *timeout)
{
    int err;

    err = tap_ctl_write_message(sfd, message, timeout);
    if (err) {
        EPRINTF("failed to send '%s' message\n",
                tapdisk_message_name(message->type));
        return err;
    }

    err = tap_ctl_read_message(sfd, message, timeout);
    if (err) {
        EPRINTF("failed to receive '%s' message\n",
                tapdisk_message_name(message->type));
        return err;
    }

    return 0;
}

示例#4

文件： tap-ctl-stats.c 项目： DarumasLegs/blktap

int
tap_ctl_stats_fwrite(pid_t pid, int minor, FILE *stream)
{
	tapdisk_message_t message;
	int sfd = -1, prot, flags, err;
	size_t len, bufsz;
	char *buf = MAP_FAILED;

	prot  = PROT_READ|PROT_WRITE;
	flags = MAP_ANONYMOUS|MAP_PRIVATE;
	bufsz = sysconf(_SC_PAGE_SIZE);

	buf = mmap(NULL, bufsz, prot, flags, -1, 0);
	if (buf == MAP_FAILED) {
		buf = NULL;
		err = -ENOMEM;
		goto out;
	}

	sfd = _tap_ctl_stats_connect_and_send(pid, minor);
	if (sfd < 0) {
		err = sfd;
		goto out;
	}

	err = tap_ctl_read_message(sfd, &message, NULL);
	if (err)
		goto out;

	len = message.u.info.length;
	err = len;
	if (len < 0)
		goto out;

	while (len) {
		fd_set rfds;
		size_t in, out;
		int n;

		FD_ZERO(&rfds);
		FD_SET(sfd, &rfds);

		n = select(sfd + 1, &rfds, NULL, NULL, NULL);
		err = n;
		if (n < 0)
			goto out;

		in = read(sfd, buf, bufsz);
		err = in;
		if (in <= 0)
			goto out;

		len -= in;

		out = fwrite(buf, in, 1, stream);
		if (out != in) {
			err = -errno;
			goto out;
		}
	}

out:
	if (sfd >= 0)
		close(sfd);
	if (buf != MAP_FAILED)
		munmap(buf, bufsz);

	return err;
}