+static
+uint64_t get_session_size_one_more_packet_per_stream(struct ltt_session *session,
+ uint64_t cur_nr_packets)
+{
+ uint64_t tot_size = 0;
+
+ if (session->kernel_session) {
+ struct ltt_kernel_channel *chan;
+ struct ltt_kernel_session *ksess = session->kernel_session;
+
+ cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
+ if (cur_nr_packets >= chan->channel->attr.num_subbuf) {
+ /*
+ * Don't take channel into account if we
+ * already grab all its packets.
+ */
+ continue;
+ }
+ tot_size += chan->channel->attr.subbuf_size
+ * chan->stream_count;
+ }
+ }
+
+ if (session->ust_session) {
+ struct ltt_ust_session *usess = session->ust_session;
+
+ tot_size += ust_app_get_size_one_more_packet_per_stream(usess,
+ cur_nr_packets);
+ }
+
+ return tot_size;
+}
+
+/*
+ * Calculate the number of packets we can grab from each stream that
+ * fits within the overall snapshot max size.
+ *
+ * Returns -1 on error, 0 means infinite number of packets, else > 0 is
+ * the number of packets per stream.
+ *
+ * TODO: this approach is not perfect: we consider the worse case
+ * (packet filling the sub-buffers) as an upper bound, but we could do
+ * better if we do this calculation while we actually grab the packet
+ * content: we would know how much padding we don't actually store into
+ * the file.
+ *
+ * This algorithm is currently bounded by the number of packets per
+ * stream.
+ *
+ * Since we call this algorithm before actually grabbing the data, it's
+ * an approximation: for instance, applications could appear/disappear
+ * in between this call and actually grabbing data.
+ */
+static
+int64_t get_session_nb_packets_per_stream(struct ltt_session *session, uint64_t max_size)
+{
+ int64_t size_left;
+ uint64_t cur_nb_packets = 0;
+
+ if (!max_size) {
+ return 0; /* Infinite */
+ }
+
+ size_left = max_size;
+ for (;;) {
+ uint64_t one_more_packet_tot_size;
+
+ one_more_packet_tot_size = get_session_size_one_more_packet_per_stream(session,
+ cur_nb_packets);
+ if (!one_more_packet_tot_size) {
+ /* We are already grabbing all packets. */
+ break;
+ }
+ size_left -= one_more_packet_tot_size;
+ if (size_left < 0) {
+ break;
+ }
+ cur_nb_packets++;
+ }
+ if (!cur_nb_packets) {
+ /* Not enough room to grab one packet of each stream, error. */
+ return -1;
+ }
+ return cur_nb_packets;
+}
+
+/*
+ * Command LTTNG_SNAPSHOT_RECORD from lib lttng ctl.
+ *
+ * The wait parameter is ignored so this call always wait for the snapshot to
+ * complete before returning.
+ *
+ * Return LTTNG_OK on success or else a LTTNG_ERR code.
+ */
+int cmd_snapshot_record(struct ltt_session *session,
+ struct lttng_snapshot_output *output, int wait)
+{
+ int ret = LTTNG_OK;
+ unsigned int use_tmp_output = 0;
+ struct snapshot_output tmp_output;
+ unsigned int snapshot_success = 0;
+ char datetime[16];
+
+ assert(session);
+ assert(output);
+
+ DBG("Cmd snapshot record for session %s", session->name);
+
+ /* Get the datetime for the snapshot output directory. */
+ ret = utils_get_current_time_str("%Y%m%d-%H%M%S", datetime,
+ sizeof(datetime));
+ if (!ret) {
+ ret = LTTNG_ERR_INVALID;
+ goto error;
+ }
+
+ /*
+ * Permission denied to create an output if the session is not
+ * set in no output mode.
+ */
+ if (session->output_traces) {
+ ret = LTTNG_ERR_NOT_SNAPSHOT_SESSION;
+ goto error;
+ }
+
+ /* The session needs to be started at least once. */
+ if (!session->has_been_started) {
+ ret = LTTNG_ERR_START_SESSION_ONCE;
+ goto error;
+ }
+
+ /* Use temporary output for the session. */
+ if (*output->ctrl_url != '\0') {
+ ret = snapshot_output_init(output->max_size, output->name,
+ output->ctrl_url, output->data_url, session->consumer,
+ &tmp_output, NULL);
+ if (ret < 0) {
+ if (ret == -ENOMEM) {
+ ret = LTTNG_ERR_NOMEM;
+ } else {
+ ret = LTTNG_ERR_INVALID;
+ }
+ goto error;
+ }
+ /* Use the global session count for the temporary snapshot. */
+ tmp_output.nb_snapshot = session->snapshot.nb_snapshot;
+
+ /* Use the global datetime */
+ memcpy(tmp_output.datetime, datetime, sizeof(datetime));
+ use_tmp_output = 1;
+ }
+
+ if (use_tmp_output) {
+ int64_t nb_packets_per_stream;
+
+ nb_packets_per_stream = get_session_nb_packets_per_stream(session,
+ tmp_output.max_size);
+ if (nb_packets_per_stream < 0) {
+ ret = LTTNG_ERR_MAX_SIZE_INVALID;
+ goto error;
+ }
+
+ if (session->kernel_session) {
+ ret = record_kernel_snapshot(session->kernel_session,
+ &tmp_output, session,
+ wait, nb_packets_per_stream);
+ if (ret != LTTNG_OK) {
+ goto error;
+ }
+ }
+
+ if (session->ust_session) {
+ ret = record_ust_snapshot(session->ust_session,
+ &tmp_output, session,
+ wait, nb_packets_per_stream);
+ if (ret != LTTNG_OK) {
+ goto error;
+ }
+ }
+
+ snapshot_success = 1;
+ } else {
+ struct snapshot_output *sout;
+ struct lttng_ht_iter iter;
+
+ rcu_read_lock();
+ cds_lfht_for_each_entry(session->snapshot.output_ht->ht,
+ &iter.iter, sout, node.node) {
+ int64_t nb_packets_per_stream;
+
+ /*
+ * Make a local copy of the output and assign the possible
+ * temporary value given by the caller.
+ */
+ memset(&tmp_output, 0, sizeof(tmp_output));
+ memcpy(&tmp_output, sout, sizeof(tmp_output));
+
+ if (output->max_size != (uint64_t) -1ULL) {
+ tmp_output.max_size = output->max_size;
+ }
+
+ nb_packets_per_stream = get_session_nb_packets_per_stream(session,
+ tmp_output.max_size);
+ if (nb_packets_per_stream < 0) {
+ ret = LTTNG_ERR_MAX_SIZE_INVALID;
+ rcu_read_unlock();
+ goto error;
+ }
+
+ /* Use temporary name. */
+ if (*output->name != '\0') {
+ if (lttng_strncpy(tmp_output.name, output->name,
+ sizeof(tmp_output.name))) {
+ ret = LTTNG_ERR_INVALID;
+ rcu_read_unlock();
+ goto error;
+ }
+ }
+
+ tmp_output.nb_snapshot = session->snapshot.nb_snapshot;
+ memcpy(tmp_output.datetime, datetime, sizeof(datetime));
+
+ if (session->kernel_session) {
+ ret = record_kernel_snapshot(session->kernel_session,
+ &tmp_output, session,
+ wait, nb_packets_per_stream);
+ if (ret != LTTNG_OK) {
+ rcu_read_unlock();
+ goto error;
+ }
+ }
+
+ if (session->ust_session) {
+ ret = record_ust_snapshot(session->ust_session,
+ &tmp_output, session,
+ wait, nb_packets_per_stream);
+ if (ret != LTTNG_OK) {
+ rcu_read_unlock();
+ goto error;
+ }
+ }
+ snapshot_success = 1;
+ }
+ rcu_read_unlock();
+ }
+
+ if (snapshot_success) {
+ session->snapshot.nb_snapshot++;
+ } else {
+ ret = LTTNG_ERR_SNAPSHOT_FAIL;
+ }
+
+error:
+ return ret;
+}
+
+/*
+ * Command LTTNG_SET_SESSION_SHM_PATH processed by the client thread.
+ */
+int cmd_set_session_shm_path(struct ltt_session *session,
+ const char *shm_path)
+{
+ /* Safety net */
+ assert(session);
+
+ /*
+ * Can only set shm path before session is started.
+ */
+ if (session->has_been_started) {
+ return LTTNG_ERR_SESSION_STARTED;
+ }
+
+ strncpy(session->shm_path, shm_path,
+ sizeof(session->shm_path));
+ session->shm_path[sizeof(session->shm_path) - 1] = '\0';
+
+ return 0;
+}
+
+/*
+ * Command LTTNG_ROTATE_SESSION from the lttng-ctl library.
+ *
+ * Ask the consumer to rotate the session output directory.
+ * The session lock must be held.
+ *
+ * Return LTTNG_OK on success or else a LTTNG_ERR code.
+ */
+int cmd_rotate_session(struct ltt_session *session,
+ struct lttng_rotate_session_return *rotate_return)
+{
+ int ret;
+ size_t strf_ret;
+ struct tm *timeinfo;
+ char datetime[16];
+ time_t now;
+ bool ust_active = false;
+
+ assert(session);
+
+ if (!session->has_been_started) {
+ ret = -LTTNG_ERR_START_SESSION_ONCE;
+ goto end;
+ }
+
+ if (session->live_timer || session->snapshot_mode ||
+ !session->output_traces) {
+ ret = -LTTNG_ERR_ROTATION_NOT_AVAILABLE;
+ goto end;
+ }
+
+ /*
+ * Unsupported feature in lttng-relayd before 2.11.
+ */
+ if (session->consumer->type == CONSUMER_DST_NET &&
+ (session->consumer->relay_major_version == 2 &&
+ session->consumer->relay_minor_version < 11)) {
+ ret = -LTTNG_ERR_ROTATION_NOT_AVAILABLE;
+ goto end;
+ }
+
+ if (session->rotate_pending || session->rotate_pending_relay) {
+ ret = -LTTNG_ERR_ROTATION_PENDING;
+ DBG("Rotate already in progress");
+ goto end;
+ }
+
+ /*
+ * After a stop, we only allow one rotation to occur, the other ones are
+ * useless until a new start.
+ */
+ if (session->rotated_after_last_stop) {
+ DBG("Session \"%s\" was already rotated after stop, refusing rotation",
+ session->name);
+ ret = -LTTNG_ERR_ROTATION_MULTIPLE_AFTER_STOP;
+ goto end;
+ }
+
+ /* Special case for the first rotation. */
+ if (session->rotate_count == 0) {
+ const char *base_path = NULL;
+
+ /* Either one of the two sessions is enough to get the root path. */
+ if (session->kernel_session) {
+ base_path = session_get_base_path(session);
+ } else if (session->ust_session) {
+ base_path = session_get_base_path(session);
+ } else {
+ assert(0);
+ }
+ assert(base_path);
+ ret = lttng_strncpy(session->rotation_chunk.current_rotate_path,
+ base_path,
+ sizeof(session->rotation_chunk.current_rotate_path));
+ if (ret) {
+ ERR("Failed to copy session base path to current rotation chunk path");
+ ret = -LTTNG_ERR_UNK;
+ goto end;
+ }
+ } else {
+ /*
+ * The currently active tracing path is now the folder we
+ * want to rotate.
+ */
+ ret = lttng_strncpy(session->rotation_chunk.current_rotate_path,
+ session->rotation_chunk.active_tracing_path,
+ sizeof(session->rotation_chunk.current_rotate_path));
+ if (ret) {
+ ERR("Failed to copy the active tracing path to the current rotate path");
+ ret = -LTTNG_ERR_UNK;
+ goto end;
+ }
+ }
+ DBG("Current rotate path %s", session->rotation_chunk.current_rotate_path);
+
+ session->rotate_count++;
+ session->rotate_pending = true;
+ session->rotation_state = LTTNG_ROTATION_STATE_ONGOING;
+
+ /*
+ * Create the path name for the next chunk.
+ */
+ now = time(NULL);
+ if (now == (time_t) -1) {
+ ret = -LTTNG_ERR_ROTATION_NOT_AVAILABLE;
+ goto end;
+ }
+ session->last_chunk_start_ts = session->current_chunk_start_ts;
+ session->current_chunk_start_ts = now;
+
+ timeinfo = localtime(&now);
+ if (!timeinfo) {
+ PERROR("Failed to sample local time in rotate session command");
+ ret = -LTTNG_ERR_UNK;
+ goto end;
+ }
+ strf_ret = strftime(datetime, sizeof(datetime), "%Y%m%d-%H%M%S",
+ timeinfo);
+ if (!strf_ret) {
+ ERR("Failed to format local time timestamp in rotate session command");
+ ret = -LTTNG_ERR_UNK;
+ goto end;
+ }
+ if (session->kernel_session) {
+ /*
+ * The active path for the next rotation/destroy.
+ * Ex: ~/lttng-traces/auto-20170922-111748/20170922-111754-42
+ */
+ ret = snprintf(session->rotation_chunk.active_tracing_path,
+ sizeof(session->rotation_chunk.active_tracing_path),
+ "%s/%s-%" PRIu64,
+ session_get_base_path(session),
+ datetime, session->rotate_count + 1);
+ if (ret < 0 || ret == sizeof(session->rotation_chunk.active_tracing_path)) {
+ ERR("Failed to format active kernel tracing path in rotate session command");
+ ret = -LTTNG_ERR_UNK;
+ goto end;
+ }
+ /*
+ * The sub-directory for the consumer
+ * Ex: /20170922-111754-42/kernel
+ */
+ ret = snprintf(session->kernel_session->consumer->chunk_path,
+ sizeof(session->kernel_session->consumer->chunk_path),
+ "/%s-%" PRIu64, datetime,
+ session->rotate_count + 1);
+ if (ret < 0 || ret == sizeof(session->kernel_session->consumer->chunk_path)) {
+ ERR("Failed to format the kernel consumer's sub-directory in rotate session command");
+ ret = -LTTNG_ERR_UNK;
+ goto end;
+ }
+ /*
+ * Create the new chunk folder, before the rotation begins so we don't
+ * race with the consumer/tracer activity.
+ */
+ ret = domain_mkdir(session->kernel_session->consumer, session,
+ session->kernel_session->uid,
+ session->kernel_session->gid);
+ if (ret) {
+ ERR("Failed to create kernel session tracing path at %s",
+ session->kernel_session->consumer->chunk_path);
+ ret = -LTTNG_ERR_CREATE_DIR_FAIL;
+ goto end;
+ }
+ ret = kernel_rotate_session(session);
+ if (ret != LTTNG_OK) {
+ ret = -ret;
+ goto end;
+ }
+ }
+ if (session->ust_session) {
+ ret = snprintf(session->rotation_chunk.active_tracing_path,
+ PATH_MAX, "%s/%s-%" PRIu64,
+ session_get_base_path(session),
+ datetime, session->rotate_count + 1);
+ if (ret < 0) {
+ ERR("Failed to format active UST tracing path in rotate session command");
+ ret = -LTTNG_ERR_UNK;
+ goto end;
+ }
+ ret = snprintf(session->ust_session->consumer->chunk_path,
+ PATH_MAX, "/%s-%" PRIu64, datetime,
+ session->rotate_count + 1);
+ if (ret < 0) {
+ ERR("Failed to format the UST consumer's sub-directory in rotate session command");
+ ret = -LTTNG_ERR_UNK;
+ goto end;
+ }
+ /*
+ * Create the new chunk folder, before the rotation begins so we don't
+ * race with the consumer/tracer activity.
+ */
+ ret = domain_mkdir(session->ust_session->consumer, session,
+ session->ust_session->uid,
+ session->ust_session->gid);
+ ret = ust_app_rotate_session(session, &ust_active);
+ if (ret != LTTNG_OK) {
+ ret = -LTTNG_ERR_CREATE_DIR_FAIL;
+ goto end;
+ }
+ /*
+ * Handle the case where we did not start a rotation on any channel.
+ * The consumer will never wake up the rotation thread to perform the
+ * rename, so we have to do it here while we hold the session and
+ * session_list locks.
+ */
+ if (!session->kernel_session && !ust_active) {
+ ret = rename_complete_chunk(session, now);
+ if (ret < 0) {
+ ERR("Failed to rename completed rotation chunk");
+ goto end;
+ }
+ session->rotate_pending = false;
+ session->rotation_state = LTTNG_ROTATION_STATE_COMPLETED;
+ }
+ }
+
+ if (!session->active) {
+ session->rotated_after_last_stop = true;
+ }
+
+ if (rotate_return) {
+ rotate_return->rotation_id = session->rotate_count;
+ }
+
+ DBG("Cmd rotate session %s, rotate_id %" PRIu64 " sent", session->name,
+ session->rotate_count);
+ ret = LTTNG_OK;
+
+end:
+ return ret;
+}
+
+/*
+ * Command LTTNG_ROTATION_GET_INFO from the lttng-ctl library.
+ *
+ * Check if the session has finished its rotation.
+ *
+ * Return 0 on success or else a LTTNG_ERR code.
+ */
+int cmd_rotate_get_info(struct ltt_session *session,
+ struct lttng_rotation_get_info_return *info_return,
+ uint64_t rotation_id)
+{
+ int ret;
+
+ assert(session);
+
+ DBG("Cmd rotate_get_info session %s, rotation id %" PRIu64, session->name,
+ session->rotate_count);
+
+ if (session->rotate_count != rotation_id) {
+ info_return->status = (int32_t) LTTNG_ROTATION_STATE_EXPIRED;
+ ret = LTTNG_OK;
+ goto end;
+ }
+
+ switch (session->rotation_state) {
+ case LTTNG_ROTATION_STATE_ONGOING:
+ DBG("Reporting that rotation id %" PRIu64 " of session %s is still pending",
+ rotation_id, session->name);
+ break;
+ case LTTNG_ROTATION_STATE_COMPLETED:
+ ret = lttng_strncpy(info_return->path,
+ session->rotation_chunk.current_rotate_path,
+ sizeof(info_return->path));
+ if (ret) {
+ ERR("Failed to copy active tracing path to rotate_get_info reply");
+ info_return->status = LTTNG_ROTATION_STATUS_ERROR;
+ ret = -LTTNG_ERR_UNK;
+ goto end;
+ }
+ break;
+ case LTTNG_ROTATION_STATE_ERROR:
+ DBG("Reporting that an error occurred during rotation %" PRIu64 " of session %s",
+ rotation_id, session->name);
+ break;
+ default:
+ abort();
+ }
+
+ info_return->status = (int32_t) session->rotation_state;
+ ret = LTTNG_OK;
+end:
+ return ret;
+}
+
+/*
+ * Command LTTNG_ROTATION_SET_SCHEDULE from the lttng-ctl library.
+ *
+ * Configure the automatic rotation parameters.
+ * Set to -1ULL to disable them.
+ *
+ * Return 0 on success or else an LTTNG_ERR code.
+ */
+int cmd_rotation_set_schedule(struct ltt_session *session,
+ uint64_t timer_us, uint64_t size)
+{
+ int ret;
+
+ assert(session);
+
+ DBG("Cmd rotate set schedule session %s", session->name);
+
+ if (session->live_timer || session->snapshot_mode ||
+ !session->output_traces) {
+ ret = LTTNG_ERR_ROTATION_NOT_AVAILABLE;
+ goto end;
+ }
+
+ /* Trying to override an already active timer. */
+ if (timer_us && timer_us != -1ULL && session->rotate_timer_period) {
+ ret = LTTNG_ERR_ROTATION_TIMER_SET;
+ goto end;
+ /* Trying to disable an inactive timer. */
+ } else if (timer_us == -1ULL && !session->rotate_timer_period) {
+ ret = LTTNG_ERR_ROTATION_NO_TIMER_SET;
+ goto end;
+ }
+
+ if (timer_us && !session->rotate_timer_period) {
+ if (timer_us > UINT_MAX) {
+ ret = LTTNG_ERR_INVALID;
+ goto end;
+ }
+
+ session->rotate_timer_period = timer_us;
+ /*
+ * Only start the timer if the session is active, otherwise
+ * it will be started when the session starts.
+ */
+ if (session->active) {
+ ret = sessiond_rotate_timer_start(session, timer_us);
+ if (ret) {
+ ERR("Failed to enable rotate timer");
+ ret = LTTNG_ERR_UNK;
+ goto end;
+ }
+ }
+ } else if (timer_us == -1ULL && session->rotate_timer_period > 0) {
+ sessiond_rotate_timer_stop(session);
+ session->rotate_timer_period = 0;
+ }
+
+ ret = LTTNG_OK;
+
+ goto end;
+
+end:
+ return ret;
+}
+
+/*
+ * Command ROTATE_GET_CURRENT_PATH from the lttng-ctl library.
+ *
+ * Configure the automatic rotation parameters.
+ * Set to -1ULL to disable them.
+ *
+ * Return LTTNG_OK on success or else a LTTNG_ERR code.
+ */
+int cmd_session_get_current_output(struct ltt_session *session,
+ struct lttng_session_get_current_output_return *output_return)
+{
+ int ret;
+ const char *path;
+
+ if (!session->snapshot_mode) {
+ if (session->rotate_count == 0) {
+ if (session->kernel_session) {
+ path = session_get_base_path(session);
+ } else if (session->ust_session) {
+ path = session_get_base_path(session);
+ } else {
+ abort();
+ }
+ assert(path);
+ } else {
+ path = session->rotation_chunk.active_tracing_path;
+ }
+ } else {
+ /*
+ * A snapshot session does not have a "current" trace archive
+ * location.
+ */
+ path = "";
+ }
+
+ DBG("Cmd get current output for session %s, returning %s",
+ session->name, path);
+
+ ret = lttng_strncpy(output_return->path,
+ path,
+ sizeof(output_return->path));
+ if (ret) {
+ ERR("Failed to copy trace output path to session get current output command reply");
+ ret = -LTTNG_ERR_UNK;
+ goto end;
+ }
+
+ ret = LTTNG_OK;
+end:
+ return ret;
+}
+