static
int run_as_cmd(struct run_as_worker *worker,
enum run_as_cmd cmd,
struct run_as_data *data,
uid_t uid, gid_t gid)
{
ssize_t readlen, writelen;
struct run_as_ret recvret;
/*
* If we are non-root, we can only deal with our own uid.
*/
if (geteuid() != 0) {
if (uid != geteuid()) {
recvret.ret = -1;
recvret._errno = EPERM;
ERR("Client (%d)/Server (%d) UID mismatch (and sessiond is not root)",
(int) uid, (int) geteuid());
goto end;
}
}
data->cmd = cmd;
data->uid = uid;
data->gid = gid;
writelen = lttcomm_send_unix_sock(worker->sockpair[0], data,
sizeof(*data));
if (writelen < sizeof(*data)) {
PERROR("Error writing message to run_as");
recvret.ret = -1;
recvret._errno = errno;
goto end;
}
/* receive return value */
readlen = lttcomm_recv_unix_sock(worker->sockpair[0], &recvret,
sizeof(recvret));
if (!readlen) {
ERR("Run-as worker has hung-up during run_as_cmd");
recvret.ret = -1;
recvret._errno = EIO;
goto end;
} else if (readlen < sizeof(recvret)) {
PERROR("Error reading response from run_as");
recvret.ret = -1;
recvret._errno = errno;
}
if (do_recv_fd(worker, cmd, &recvret.ret)) {
recvret.ret = -1;
recvret._errno = EIO;
}
end:
errno = recvret._errno;
return recvret.ret;
}
/*
* Send data on a unix socket using the liblttsessiondcomm API.
*
* Return lttcomm error code.
*/
static int send_unix_sock(int sock, void *buf, size_t len)
{
/* Check valid length */
if (len == 0) {
return -1;
}
return lttcomm_send_unix_sock(sock, buf, len);
}
static
int run_as_worker(struct run_as_worker *worker)
{
int ret;
ssize_t writelen;
struct run_as_ret sendret;
size_t proc_orig_len;
/*
* Initialize worker. Set a different process cmdline.
*/
proc_orig_len = strlen(worker->procname);
memset(worker->procname, 0, proc_orig_len);
strncpy(worker->procname, DEFAULT_RUN_AS_WORKER_NAME, proc_orig_len);
ret = lttng_prctl(PR_SET_NAME,
(unsigned long) DEFAULT_RUN_AS_WORKER_NAME, 0, 0, 0);
if (ret && ret != -ENOSYS) {
/* Don't fail as this is not essential. */
PERROR("prctl PR_SET_NAME");
ret = 0;
}
sendret.ret = 0;
sendret._errno = 0;
writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret,
sizeof(sendret));
if (writelen < sizeof(sendret)) {
PERROR("lttcomm_send_unix_sock error");
ret = EXIT_FAILURE;
goto end;
}
for (;;) {
ret = handle_one_cmd(worker);
if (ret < 0) {
ret = EXIT_FAILURE;
goto end;
} else if (ret > 0) {
break;
} else {
continue; /* Next command. */
}
}
ret = EXIT_SUCCESS;
end:
return ret;
}
/*
* Send var len data to the session daemon.
*
* On success, returns the number of bytes sent (>=0)
* On error, returns -1
*/
static int send_session_varlen(void *data, size_t len)
{
int ret;
if (!connected) {
ret = -LTTNG_ERR_NO_SESSIOND;
goto end;
}
if (!data || !len) {
ret = 0;
goto end;
}
ret = lttcomm_send_unix_sock(sessiond_socket, data, len);
if (ret < 0) {
ret = -LTTNG_ERR_FATAL;
}
end:
return ret;
}
/*
* Check session daemon health for a specific health component.
*
* Return 0 if health is OK or else 1 if BAD.
*
* Any other negative value is a lttng error code which can be translated with
* lttng_strerror().
*/
int lttng_health_check(enum lttng_health_component c)
{
int sock, ret;
struct lttcomm_health_msg msg;
struct lttcomm_health_data reply;
/* Connect to the sesssion daemon */
sock = lttcomm_connect_unix_sock(health_sock_path);
if (sock < 0) {
ret = -LTTNG_ERR_NO_SESSIOND;
goto error;
}
msg.cmd = LTTNG_HEALTH_CHECK;
msg.component = c;
ret = lttcomm_send_unix_sock(sock, (void *)&msg, sizeof(msg));
if (ret < 0) {
ret = -LTTNG_ERR_FATAL;
goto close_error;
}
ret = lttcomm_recv_unix_sock(sock, (void *)&reply, sizeof(reply));
if (ret < 0) {
ret = -LTTNG_ERR_FATAL;
goto close_error;
}
ret = reply.ret_code;
close_error:
close(sock);
error:
return ret;
}
static
int run_as_cmd(struct run_as_worker *worker,
enum run_as_cmd cmd,
struct run_as_data *data,
struct run_as_ret *ret_value,
uid_t uid, gid_t gid)
{
int ret = 0;
ssize_t readlen, writelen;
/*
* If we are non-root, we can only deal with our own uid.
*/
if (geteuid() != 0) {
if (uid != geteuid()) {
ret = -1;
ret_value->_errno = EPERM;
ERR("Client (%d)/Server (%d) UID mismatch (and sessiond is not root)",
(int) uid, (int) geteuid());
goto end;
}
}
data->cmd = cmd;
data->uid = uid;
data->gid = gid;
/*
* Stage 1: Send the run_as_data struct to the worker process
*/
writelen = lttcomm_send_unix_sock(worker->sockpair[0], data,
sizeof(*data));
if (writelen < sizeof(*data)) {
PERROR("Error writing message to run_as");
ret = -1;
ret_value->_errno = EIO;
goto end;
}
/*
* Stage 2: Send file descriptor to the worker process if needed
*/
ret = send_fd_to_worker(worker, data->cmd, data->fd);
if (ret) {
PERROR("do_send_fd error");
ret = -1;
ret_value->_errno = EIO;
goto end;
}
/*
* Stage 3: Wait for the execution of the command
*/
/*
* Stage 4: Receive the run_as_ret struct containing the return value and
* errno
*/
readlen = lttcomm_recv_unix_sock(worker->sockpair[0], ret_value,
sizeof(*ret_value));
if (!readlen) {
ERR("Run-as worker has hung-up during run_as_cmd");
ret = -1;
ret_value->_errno = EIO;
goto end;
} else if (readlen < sizeof(*ret_value)) {
PERROR("Error reading response from run_as");
ret = -1;
ret_value->_errno = errno;
goto end;
}
if (ret_value->_error) {
/* Skip stage 5 on error as there will be no fd to receive. */
goto end;
}
/*
* Stage 5: Receive file descriptor if needed
*/
ret = recv_fd_from_worker(worker, data->cmd, &ret_value->fd);
if (ret < 0) {
ERR("Error receiving fd");
ret = -1;
ret_value->_errno = EIO;
}
end:
return ret;
}
/*
* Return < 0 on error, 0 if OK, 1 on hangup.
*/
static
int handle_one_cmd(struct run_as_worker *worker)
{
int ret = 0;
struct run_as_data data;
ssize_t readlen, writelen;
struct run_as_ret sendret;
run_as_fct cmd;
uid_t prev_euid;
memset(&sendret, 0, sizeof(sendret));
sendret.fd = -1;
/*
* Stage 1: Receive run_as_data struct from the master.
* The structure contains the command type and all the parameters needed for
* its execution
*/
readlen = lttcomm_recv_unix_sock(worker->sockpair[1], &data,
sizeof(data));
if (readlen == 0) {
/* hang up */
ret = 1;
goto end;
}
if (readlen < sizeof(data)) {
PERROR("lttcomm_recv_unix_sock error");
ret = -1;
goto end;
}
cmd = run_as_enum_to_fct(data.cmd);
if (!cmd) {
ret = -1;
goto end;
}
/*
* Stage 2: Receive file descriptor from master.
* Some commands need a file descriptor as input so if it's needed we
* receive the fd using the Unix socket.
*/
ret = recv_fd_from_master(worker, data.cmd, &data.fd);
if (ret < 0) {
PERROR("recv_fd_from_master error");
ret = -1;
goto end;
}
prev_euid = getuid();
if (data.gid != getegid()) {
ret = setegid(data.gid);
if (ret < 0) {
sendret._error = true;
sendret._errno = errno;
PERROR("setegid");
goto write_return;
}
}
if (data.uid != prev_euid) {
ret = seteuid(data.uid);
if (ret < 0) {
sendret._error = true;
sendret._errno = errno;
PERROR("seteuid");
goto write_return;
}
}
/*
* Also set umask to 0 for mkdir executable bit.
*/
umask(0);
/*
* Stage 3: Execute the command
*/
ret = (*cmd)(&data, &sendret);
if (ret < 0) {
DBG("Execution of command returned an error");
}
write_return:
ret = cleanup_received_fd(data.cmd, data.fd);
if (ret < 0) {
ERR("Error cleaning up FD");
goto end;
}
/*
* Stage 4: Send run_as_ret structure to the master.
* This structure contain the return value of the command and the errno.
*/
writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret,
sizeof(sendret));
if (writelen < sizeof(sendret)) {
PERROR("lttcomm_send_unix_sock error");
ret = -1;
goto end;
}
/*
* Stage 5: Send file descriptor to the master
* Some commands return a file descriptor so if it's needed we pass it back
* to the master using the Unix socket.
*/
ret = send_fd_to_master(worker, data.cmd, sendret.fd);
if (ret < 0) {
DBG("Sending FD to master returned an error");
goto end;
}
if (seteuid(prev_euid) < 0) {
PERROR("seteuid");
ret = -1;
goto end;
}
ret = 0;
end:
return ret;
}
/*
* Return < 0 on error, 0 if OK, 1 on hangup.
*/
static
int handle_one_cmd(struct run_as_worker *worker)
{
int ret = 0;
struct run_as_data data;
ssize_t readlen, writelen;
struct run_as_ret sendret;
run_as_fct cmd;
uid_t prev_euid;
/* Read data */
readlen = lttcomm_recv_unix_sock(worker->sockpair[1], &data,
sizeof(data));
if (readlen == 0) {
/* hang up */
ret = 1;
goto end;
}
if (readlen < sizeof(data)) {
PERROR("lttcomm_recv_unix_sock error");
ret = -1;
goto end;
}
cmd = run_as_enum_to_fct(data.cmd);
if (!cmd) {
ret = -1;
goto end;
}
prev_euid = getuid();
if (data.gid != getegid()) {
ret = setegid(data.gid);
if (ret < 0) {
PERROR("setegid");
goto write_return;
}
}
if (data.uid != prev_euid) {
ret = seteuid(data.uid);
if (ret < 0) {
PERROR("seteuid");
goto write_return;
}
}
/*
* Also set umask to 0 for mkdir executable bit.
*/
umask(0);
ret = (*cmd)(&data);
write_return:
sendret.ret = ret;
sendret._errno = errno;
/* send back return value */
writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret,
sizeof(sendret));
if (writelen < sizeof(sendret)) {
PERROR("lttcomm_send_unix_sock error");
ret = -1;
goto end;
}
ret = do_send_fd(worker, data.cmd, ret);
if (ret) {
PERROR("do_send_fd error");
ret = -1;
goto end;
}
if (seteuid(prev_euid) < 0) {
PERROR("seteuid");
ret = -1;
goto end;
}
ret = 0;
end:
return ret;
}
/*
* Thread managing health check socket.
*/
static void *thread_manage_health(void *data)
{
const bool is_root = (getuid() == 0);
int sock = -1, new_sock = -1, ret, i, pollfd, err = -1;
uint32_t revents, nb_fd;
struct lttng_poll_event events;
struct health_comm_msg msg;
struct health_comm_reply reply;
/* Thread-specific quit pipe. */
struct thread_notifiers *notifiers = data;
const int quit_pipe_read_fd = lttng_pipe_get_readfd(
notifiers->quit_pipe);
DBG("[thread] Manage health check started");
rcu_register_thread();
/*
* Created with a size of two for:
* - client socket
* - thread quit pipe
*/
ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC);
if (ret < 0) {
goto error;
}
/* Create unix socket */
sock = lttcomm_create_unix_sock(config.health_unix_sock_path.value);
if (sock < 0) {
ERR("Unable to create health check Unix socket");
goto error;
}
if (is_root) {
/* lttng health client socket path permissions */
gid_t gid;
ret = utils_get_group_id(config.tracing_group_name.value, true, &gid);
if (ret) {
/* Default to root group. */
gid = 0;
}
ret = chown(config.health_unix_sock_path.value, 0, gid);
if (ret < 0) {
ERR("Unable to set group on %s", config.health_unix_sock_path.value);
PERROR("chown");
goto error;
}
ret = chmod(config.health_unix_sock_path.value,
S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
if (ret < 0) {
ERR("Unable to set permissions on %s", config.health_unix_sock_path.value);
PERROR("chmod");
goto error;
}
}
/*
* Set the CLOEXEC flag. Return code is useless because either way, the
* show must go on.
*/
(void) utils_set_fd_cloexec(sock);
ret = lttcomm_listen_unix_sock(sock);
if (ret < 0) {
goto error;
}
ret = lttng_poll_add(&events, quit_pipe_read_fd, LPOLLIN | LPOLLERR);
if (ret < 0) {
goto error;
}
/* Add the application registration socket */
ret = lttng_poll_add(&events, sock, LPOLLIN | LPOLLPRI);
if (ret < 0) {
goto error;
}
mark_thread_as_ready(notifiers);
while (1) {
DBG("Health check ready");
/* Infinite blocking call, waiting for transmission */
restart:
ret = lttng_poll_wait(&events, -1);
if (ret < 0) {
/*
* Restart interrupted system call.
*/
if (errno == EINTR) {
goto restart;
}
goto error;
}
nb_fd = ret;
for (i = 0; i < nb_fd; i++) {
/* Fetch once the poll data */
revents = LTTNG_POLL_GETEV(&events, i);
pollfd = LTTNG_POLL_GETFD(&events, i);
/* Event on the registration socket */
if (pollfd == sock) {
if (revents & LPOLLIN) {
continue;
} else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
ERR("Health socket poll error");
goto error;
} else {
ERR("Unexpected poll events %u for sock %d", revents, pollfd);
goto error;
}
} else {
/* Event on the thread's quit pipe. */
err = 0;
goto exit;
}
}
new_sock = lttcomm_accept_unix_sock(sock);
if (new_sock < 0) {
goto error;
}
/*
* Set the CLOEXEC flag. Return code is useless because either way, the
* show must go on.
*/
(void) utils_set_fd_cloexec(new_sock);
DBG("Receiving data from client for health...");
ret = lttcomm_recv_unix_sock(new_sock, (void *)&msg, sizeof(msg));
if (ret <= 0) {
DBG("Nothing recv() from client... continuing");
ret = close(new_sock);
if (ret) {
PERROR("close");
}
continue;
}
rcu_thread_online();
memset(&reply, 0, sizeof(reply));
for (i = 0; i < NR_HEALTH_SESSIOND_TYPES; i++) {
/*
* health_check_state returns 0 if health is
* bad.
*/
if (!health_check_state(health_sessiond, i)) {
reply.ret_code |= 1ULL << i;
}
}
DBG2("Health check return value %" PRIx64, reply.ret_code);
ret = lttcomm_send_unix_sock(new_sock, (void *) &reply,
sizeof(reply));
if (ret < 0) {
ERR("Failed to send health data back to client");
}
/* End of transmission */
ret = close(new_sock);
if (ret) {
PERROR("close");
}
}
exit:
error:
if (err) {
ERR("Health error occurred in %s", __func__);
}
DBG("Health check thread dying");
unlink(config.health_unix_sock_path.value);
if (sock >= 0) {
ret = close(sock);
if (ret) {
PERROR("close");
}
}
lttng_poll_clean(&events);
rcu_unregister_thread();
return NULL;
}
static
int handshake(struct lttng_notification_channel *channel)
{
ssize_t ret;
enum lttng_notification_channel_status status =
LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
struct lttng_notification_channel_command_handshake handshake = {
.major = LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR,
.minor = LTTNG_NOTIFICATION_CHANNEL_VERSION_MINOR,
};
struct lttng_notification_channel_message msg_header = {
.type = LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE,
.size = sizeof(handshake),
};
char send_buffer[sizeof(msg_header) + sizeof(handshake)];
memcpy(send_buffer, &msg_header, sizeof(msg_header));
memcpy(send_buffer + sizeof(msg_header), &handshake, sizeof(handshake));
pthread_mutex_lock(&channel->lock);
ret = lttcomm_send_creds_unix_sock(channel->socket, send_buffer,
sizeof(send_buffer));
if (ret < 0) {
goto end_unlock;
}
/* Receive handshake info from the sessiond. */
ret = receive_command_reply(channel, &status);
if (ret < 0) {
goto end_unlock;
}
if (!channel->version.set) {
ret = -1;
goto end_unlock;
}
if (channel->version.major != LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR) {
ret = -1;
goto end_unlock;
}
end_unlock:
pthread_mutex_unlock(&channel->lock);
return ret;
}
static
enum lttng_notification_channel_status send_condition_command(
struct lttng_notification_channel *channel,
enum lttng_notification_channel_message_type type,
const struct lttng_condition *condition)
{
int socket;
ssize_t command_size, ret;
enum lttng_notification_channel_status status =
LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
char *command_buffer = NULL;
struct lttng_notification_channel_message cmd_message = {
.type = type,
};
if (!channel) {
status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID;
goto end;
}
assert(type == LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE ||
type == LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE);
pthread_mutex_lock(&channel->lock);
socket = channel->socket;
if (!lttng_condition_validate(condition)) {
status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID;
goto end_unlock;
}
ret = lttng_condition_serialize(condition, NULL);
if (ret < 0) {
status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID;
goto end_unlock;
}
assert(ret < UINT32_MAX);
cmd_message.size = (uint32_t) ret;
command_size = ret + sizeof(
struct lttng_notification_channel_message);
command_buffer = zmalloc(command_size);
if (!command_buffer) {
goto end_unlock;
}
memcpy(command_buffer, &cmd_message, sizeof(cmd_message));
ret = lttng_condition_serialize(condition,
command_buffer + sizeof(cmd_message));
if (ret < 0) {
goto end_unlock;
}
ret = lttcomm_send_unix_sock(socket, command_buffer, command_size);
if (ret < 0) {
status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR;
goto end_unlock;
}
ret = receive_command_reply(channel, &status);
if (ret < 0) {
status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR;
goto end_unlock;
}
end_unlock:
pthread_mutex_unlock(&channel->lock);
end:
free(command_buffer);
return status;
}
