+ return buf_size;
+
+error:
+ return ret;
+}
+
+/*
+ * thread_manage_kconsumerd
+ *
+ * This thread manage the kconsumerd error sent
+ * back to the session daemon.
+ */
+static void *thread_manage_kconsumerd(void *data)
+{
+ int sock, ret;
+ enum lttcomm_return_code code;
+
+ DBG("[thread] Manage kconsumerd started");
+
+ ret = lttcomm_listen_unix_sock(kconsumerd_err_sock);
+ if (ret < 0) {
+ goto error;
+ }
+
+ sock = lttcomm_accept_unix_sock(kconsumerd_err_sock);
+ if (sock < 0) {
+ goto error;
+ }
+
+ /* Getting status code from kconsumerd */
+ ret = lttcomm_recv_unix_sock(sock, &code, sizeof(enum lttcomm_return_code));
+ if (ret <= 0) {
+ goto error;
+ }
+
+ if (code == KCONSUMERD_COMMAND_SOCK_READY) {
+ kconsumerd_cmd_sock = lttcomm_connect_unix_sock(kconsumerd_cmd_unix_sock_path);
+ if (kconsumerd_cmd_sock < 0) {
+ sem_post(&kconsumerd_sem);
+ perror("kconsumerd connect");
+ goto error;
+ }
+ /* Signal condition to tell that the kconsumerd is ready */
+ sem_post(&kconsumerd_sem);
+ DBG("Kconsumerd command socket ready");
+ } else {
+ DBG("Kconsumerd error when waiting for SOCK_READY : %s",
+ lttcomm_get_readable_code(-code));
+ goto error;
+ }
+
+ /* Wait for any kconsumerd error */
+ ret = lttcomm_recv_unix_sock(sock, &code, sizeof(enum lttcomm_return_code));
+ if (ret <= 0) {
+ ERR("Kconsumerd closed the command socket");
+ goto error;
+ }
+
+ ERR("Kconsumerd return code : %s", lttcomm_get_readable_code(-code));
+
+error:
+ kconsumerd_pid = 0;
+ DBG("Kconsumerd thread dying");
+ return NULL;
+}
+
+/*
+ * thread_manage_apps
+ *
+ * This thread manage the application socket communication
+ */
+static void *thread_manage_apps(void *data)
+{
+ int sock, ret;
+
+ /* TODO: Something more elegant is needed but fine for now */
+ /* FIXME: change all types to either uint8_t, uint32_t, uint64_t
+ * for 32-bit vs 64-bit compat processes. */
+ /* replicate in ust with version number */
+ struct {
+ int reg; /* 1:register, 0:unregister */
+ pid_t pid;
+ uid_t uid;
+ } reg_msg;
+
+ DBG("[thread] Manage apps started");
+
+ ret = lttcomm_listen_unix_sock(apps_sock);
+ if (ret < 0) {
+ goto error;
+ }
+
+ /* Notify all applications to register */
+ notify_apps(default_global_apps_pipe);
+
+ while (1) {
+ DBG("Accepting application registration");
+ /* Blocking call, waiting for transmission */
+ sock = lttcomm_accept_unix_sock(apps_sock);
+ if (sock < 0) {
+ goto error;
+ }
+
+ /* Basic recv here to handle the very simple data
+ * that the libust send to register (reg_msg).
+ */
+ ret = recv(sock, ®_msg, sizeof(reg_msg), 0);
+ if (ret < 0) {
+ perror("recv");
+ continue;
+ }
+
+ /* Add application to the global traceable list */
+ if (reg_msg.reg == 1) {
+ /* Registering */
+ ret = register_traceable_app(reg_msg.pid, reg_msg.uid);
+ if (ret < 0) {
+ /* register_traceable_app only return an error with
+ * ENOMEM. At this point, we better stop everything.
+ */
+ goto error;
+ }
+ } else {
+ /* Unregistering */
+ unregister_traceable_app(reg_msg.pid);
+ }
+ }
+
+error:
+
+ return NULL;
+}
+
+/*
+ * spawn_kconsumerd_thread
+ *
+ * Start the thread_manage_kconsumerd. This must be done after a kconsumerd
+ * exec or it will fails.
+ */
+static int spawn_kconsumerd_thread(void)
+{
+ int ret;
+
+ /* Setup semaphore */
+ sem_init(&kconsumerd_sem, 0, 0);
+
+ ret = pthread_create(&kconsumerd_thread, NULL, thread_manage_kconsumerd, (void *) NULL);
+ if (ret != 0) {
+ perror("pthread_create kconsumerd");
+ goto error;
+ }
+
+ /* Wait for the kconsumerd thread to be ready */
+ sem_wait(&kconsumerd_sem);
+
+ if (kconsumerd_pid == 0) {
+ ERR("Kconsumerd did not start");
+ goto error;
+ }
+
+ return 0;
+
+error:
+ ret = LTTCOMM_KERN_CONSUMER_FAIL;
+ return ret;
+}
+
+/*
+ * spawn_kconsumerd
+ *
+ * Fork and exec a kernel consumer daemon (kconsumerd).
+ *
+ * NOTE: It is very important to fork a kconsumerd BEFORE opening any kernel
+ * file descriptor using the libkernelctl or kernel-ctl functions. So, a
+ * kernel consumer MUST only be spawned before creating a kernel session.
+ *
+ * Return pid if successful else -1.
+ */
+static pid_t spawn_kconsumerd(void)
+{
+ int ret;
+ pid_t pid;
+
+ pid = fork();
+ if (pid == 0) {
+ /*
+ * Exec kconsumerd.
+ */
+ execlp("kconsumerd", "kconsumerd", "--quiet", NULL);
+ if (errno != 0) {
+ perror("kernel start consumer exec");
+ }
+ exit(EXIT_FAILURE);
+ } else if (pid > 0) {
+ ret = pid;
+ goto error;
+ } else {
+ perror("kernel start consumer fork");
+ ret = -errno;
+ goto error;
+ }
+
+error:
+ return ret;
+}
+
+/*
+ * start_kconsumerd
+ *
+ * Spawn the kconsumerd daemon and session daemon thread.
+ */
+static int start_kconsumerd(void)
+{
+ int ret;
+
+ DBG("Spawning kconsumerd");
+
+ pthread_mutex_lock(&kconsumerd_pid_mutex);
+ if (kconsumerd_pid == 0) {
+ ret = spawn_kconsumerd();
+ if (ret < 0) {
+ ERR("Spawning kconsumerd failed");
+ ret = LTTCOMM_KERN_CONSUMER_FAIL;
+ pthread_mutex_unlock(&kconsumerd_pid_mutex);
+ goto error;
+ }
+
+ /* Setting up the global kconsumerd_pid */
+ kconsumerd_pid = ret;
+ }
+ pthread_mutex_unlock(&kconsumerd_pid_mutex);
+
+ DBG("Kconsumerd pid %d", ret);
+
+ DBG("Spawning kconsumerd thread");
+ ret = spawn_kconsumerd_thread();
+ if (ret < 0) {
+ ERR("Fatal error spawning kconsumerd thread");
+ goto error;
+ }
+
+ return 0;
+
+error:
+ return ret;
+}
+
+/*
+ * send_kconsumerd_fds
+ *
+ * Send all stream fds of the kernel session to the consumer.
+ */
+static int send_kconsumerd_fds(int sock, struct ltt_kernel_session *session)
+{
+ int ret, i = 0;
+ /* Plus one here for the metadata fd */
+ size_t nb_fd = session->stream_count_global + 1;
+ int fds[nb_fd];
+ struct ltt_kernel_stream *stream;
+ struct ltt_kernel_channel *chan;
+ struct lttcomm_kconsumerd_header lkh;
+ struct lttcomm_kconsumerd_msg buf[nb_fd];
+
+ /* Add metadata data */
+ fds[i] = session->metadata_stream_fd;
+ buf[i].fd = fds[i];
+ buf[i].state = ACTIVE_FD;
+ buf[i].max_sb_size = session->metadata->conf->subbuf_size;
+ strncpy(buf[i].path_name, session->metadata->pathname, PATH_MAX);
+
+ cds_list_for_each_entry(chan, &session->channel_list.head, list) {
+ cds_list_for_each_entry(stream, &chan->stream_list.head, list) {
+ i++;
+ fds[i] = stream->fd;
+ buf[i].fd = stream->fd;
+ buf[i].state = stream->state;
+ buf[i].max_sb_size = chan->channel->subbuf_size;
+ strncpy(buf[i].path_name, stream->pathname, PATH_MAX);
+ }
+ }
+
+ /* Setup header */
+ lkh.payload_size = nb_fd * sizeof(struct lttcomm_kconsumerd_msg);
+ lkh.cmd_type = ADD_STREAM;
+
+ DBG("Sending kconsumerd header");
+
+ ret = lttcomm_send_unix_sock(sock, &lkh, sizeof(struct lttcomm_kconsumerd_header));
+ if (ret < 0) {
+ perror("send kconsumerd header");
+ goto error;
+ }
+
+ DBG("Sending all fds to kconsumerd");
+
+ ret = lttcomm_send_fds_unix_sock(sock, buf, fds, nb_fd, lkh.payload_size);
+ if (ret < 0) {
+ perror("send kconsumerd fds");
+ goto error;
+ }
+
+ DBG("Kconsumerd fds sent");
+
+ return 0;
+
+error:
+ return ret;
+}
+
+/*
+ * create_trace_dir
+ *
+ * Create the trace output directory.
+ */
+static int create_trace_dir(struct ltt_kernel_session *session)
+{
+ int ret;
+ struct ltt_kernel_channel *chan;
+
+ /* Create all channel directories */
+ cds_list_for_each_entry(chan, &session->channel_list.head, list) {
+ DBG("Creating trace directory at %s", chan->pathname);
+ ret = mkdir(chan->pathname, S_IRWXU | S_IRWXG );
+ if (ret < 0) {
+ perror("mkdir trace path");
+ ret = -errno;
+ goto error;
+ }
+ }
+
+ return 0;
+
+error:
+ return ret;
+}
+
+/*
+ * process_client_msg
+ *
+ * Process the command requested by the lttng client within the command
+ * context structure. This function make sure that the return structure (llm)
+ * is set and ready for transmission before returning.
+ *
+ * Return any error encountered or 0 for success.
+ */
+static int process_client_msg(struct command_ctx *cmd_ctx)
+{
+ int ret;
+
+ DBG("Processing client command %d", cmd_ctx->lsm->cmd_type);
+
+ /* Check command that needs a session */
+ switch (cmd_ctx->lsm->cmd_type) {
+ case LTTNG_CREATE_SESSION:
+ case LTTNG_LIST_SESSIONS:
+ case KERNEL_LIST_EVENTS:
+ case UST_LIST_APPS:
+ break;
+ default:
+ cmd_ctx->session = find_session_by_uuid(cmd_ctx->lsm->session_uuid);
+ if (cmd_ctx->session == NULL) {
+ ret = LTTCOMM_SELECT_SESS;
+ goto error;
+ }
+ break;
+ }
+
+ /* Check command for kernel tracing */
+ switch (cmd_ctx->lsm->cmd_type) {
+ case KERNEL_CREATE_SESSION:
+ case KERNEL_CREATE_CHANNEL:
+ case KERNEL_CREATE_STREAM:
+ case KERNEL_DISABLE_EVENT:
+ case KERNEL_ENABLE_EVENT:
+ case KERNEL_LIST_EVENTS:
+ case KERNEL_OPEN_METADATA:
+ case KERNEL_START_TRACE:
+ case KERNEL_STOP_TRACE:
+ /* TODO: reconnect to kernel tracer to check if
+ * it's loadded */
+ if (kernel_tracer_fd == 0) {
+ ret = LTTCOMM_KERN_NA;
+ goto error;
+ }
+ break;
+ }
+
+ /* Connect to ust apps if available pid */
+ if (cmd_ctx->lsm->pid > 0) {
+ /* Connect to app using ustctl API */
+ cmd_ctx->ust_sock = ust_connect_app(cmd_ctx->lsm->pid);
+ if (cmd_ctx->ust_sock < 0) {
+ ret = LTTCOMM_NO_TRACEABLE;
+ goto error;
+ }
+ }
+
+ /* Process by command type */
+ switch (cmd_ctx->lsm->cmd_type) {
+ case KERNEL_CREATE_SESSION:
+ {
+ ret = setup_lttng_msg(cmd_ctx, 0);
+ if (ret < 0) {
+ goto setup_error;
+ }
+
+ ret = start_kconsumerd();
+ if (ret < 0) {
+ goto error;
+ }
+
+ DBG("Creating kernel session");
+
+ ret = kernel_create_session(cmd_ctx->session, kernel_tracer_fd);
+ if (ret < 0) {
+ ret = LTTCOMM_KERN_SESS_FAIL;
+ goto error;
+ }
+
+ ret = LTTCOMM_OK;
+ break;
+ }
+ case KERNEL_CREATE_CHANNEL:
+ {
+ ret = setup_lttng_msg(cmd_ctx, 0);
+ if (ret < 0) {
+ goto setup_error;
+ }
+
+ DBG("Creating kernel channel");
+
+ ret = kernel_create_channel(cmd_ctx->session->kernel_session);
+
+ if (ret < 0) {
+ ret = LTTCOMM_KERN_CHAN_FAIL;
+ goto error;
+ }
+
+ ret = LTTCOMM_OK;
+ break;
+ }
+ case KERNEL_ENABLE_EVENT:
+ {
+ /* Setup lttng message with no payload */
+ ret = setup_lttng_msg(cmd_ctx, 0);
+ if (ret < 0) {
+ goto setup_error;
+ }
+
+ DBG("Enabling kernel event %s", cmd_ctx->lsm->u.event.event_name);
+
+ ret = kernel_enable_event(cmd_ctx->session->kernel_session, cmd_ctx->lsm->u.event.event_name);
+ if (ret < 0) {
+ ret = LTTCOMM_KERN_ENABLE_FAIL;
+ goto error;
+ }
+
+ ret = LTTCOMM_OK;
+ break;
+ }
+ case KERNEL_LIST_EVENTS:
+ {
+ char *event_list;
+ ssize_t size;
+
+ size = kernel_list_events(kernel_tracer_fd, &event_list);
+ if (size < 0) {
+ ret = LTTCOMM_KERN_LIST_FAIL;
+ goto error;
+ }
+
+ /*
+ * Setup lttng message with payload size set to the event list size in
+ * bytes and then copy list into the llm payload.
+ */
+ ret = setup_lttng_msg(cmd_ctx, size);
+ if (ret < 0) {
+ goto setup_error;
+ }
+
+ /* Copy event list into message payload */
+ memcpy(cmd_ctx->llm->payload, event_list, size);
+
+ free(event_list);
+
+ ret = LTTCOMM_OK;
+ break;
+ }
+ case KERNEL_OPEN_METADATA:
+ {
+ /* Setup lttng message with no payload */
+ ret = setup_lttng_msg(cmd_ctx, 0);
+ if (ret < 0) {
+ goto setup_error;
+ }
+
+ DBG("Open kernel metadata");
+
+ ret = kernel_open_metadata(cmd_ctx->session->kernel_session);
+ if (ret < 0) {
+ ret = LTTCOMM_KERN_META_FAIL;
+ goto error;
+ }
+
+ ret = LTTCOMM_OK;
+ break;
+ }
+ case KERNEL_CREATE_STREAM:
+ {
+ struct ltt_kernel_channel *chan;
+ /* Setup lttng message with no payload */
+ ret = setup_lttng_msg(cmd_ctx, 0);
+ if (ret < 0) {
+ goto setup_error;
+ }
+
+ DBG("Creating kernel stream");
+
+ ret = kernel_create_metadata_stream(cmd_ctx->session->kernel_session);
+ if (ret < 0) {
+ ERR("Kernel create metadata stream failed");
+ ret = LTTCOMM_KERN_STREAM_FAIL;
+ goto error;
+ }
+
+ /* For each channel */
+ cds_list_for_each_entry(chan, &cmd_ctx->session->kernel_session->channel_list.head, list) {
+ ret = kernel_create_channel_stream(chan);
+ if (ret < 0) {
+ ERR("Kernel create channel stream failed");
+ ret = LTTCOMM_KERN_STREAM_FAIL;
+ goto error;
+ }
+ /* Update the stream global counter */
+ cmd_ctx->session->kernel_session->stream_count_global += ret;
+ }