+ int ret;
+
+ assert(stream);
+ assert(sock >= 0);
+
+ DBG("UST consumer sending stream %" PRIu64 " to sessiond", stream->key);
+
+ /* Send stream to session daemon. */
+ ret = ustctl_send_stream_to_sessiond(sock, stream->ustream);
+ if (ret < 0) {
+ goto error;
+ }
+
+error:
+ return ret;
+}
+
+/*
+ * Send channel to sessiond.
+ *
+ * Return 0 on success or else a negative value.
+ */
+static int send_sessiond_channel(int sock,
+ struct lttng_consumer_channel *channel,
+ struct lttng_consumer_local_data *ctx, int *relayd_error)
+{
+ int ret, ret_code = LTTNG_OK;
+ struct lttng_consumer_stream *stream;
+
+ assert(channel);
+ assert(ctx);
+ assert(sock >= 0);
+
+ DBG("UST consumer sending channel %s to sessiond", channel->name);
+
+ if (channel->relayd_id != (uint64_t) -1ULL) {
+ cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
+ /* Try to send the stream to the relayd if one is available. */
+ ret = consumer_send_relayd_stream(stream, stream->chan->pathname);
+ if (ret < 0) {
+ /*
+ * Flag that the relayd was the problem here probably due to a
+ * communicaton error on the socket.
+ */
+ if (relayd_error) {
+ *relayd_error = 1;
+ }
+ ret_code = LTTNG_ERR_RELAYD_CONNECT_FAIL;
+ }
+ }
+ }
+
+ /* Inform sessiond that we are about to send channel and streams. */
+ ret = consumer_send_status_msg(sock, ret_code);
+ if (ret < 0 || ret_code != LTTNG_OK) {
+ /*
+ * Either the session daemon is not responding or the relayd died so we
+ * stop now.
+ */
+ goto error;
+ }
+
+ /* Send channel to sessiond. */
+ ret = ustctl_send_channel_to_sessiond(sock, channel->uchan);
+ if (ret < 0) {
+ goto error;
+ }
+
+ ret = ustctl_channel_close_wakeup_fd(channel->uchan);
+ if (ret < 0) {
+ goto error;
+ }
+
+ /* The channel was sent successfully to the sessiond at this point. */
+ cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
+ /* Send stream to session daemon. */
+ ret = send_sessiond_stream(sock, stream);
+ if (ret < 0) {
+ goto error;
+ }
+ }
+
+ /* Tell sessiond there is no more stream. */
+ ret = ustctl_send_stream_to_sessiond(sock, NULL);
+ if (ret < 0) {
+ goto error;
+ }
+
+ DBG("UST consumer NULL stream sent to sessiond");
+
+ return 0;
+
+error:
+ if (ret_code != LTTNG_OK) {
+ ret = -1;
+ }
+ return ret;
+}
+
+/*
+ * Creates a channel and streams and add the channel it to the channel internal
+ * state. The created stream must ONLY be sent once the GET_CHANNEL command is
+ * received.
+ *
+ * Return 0 on success or else, a negative value is returned and the channel
+ * MUST be destroyed by consumer_del_channel().
+ */
+static int ask_channel(struct lttng_consumer_local_data *ctx, int sock,
+ struct lttng_consumer_channel *channel,
+ struct ustctl_consumer_channel_attr *attr)
+{
+ int ret;
+
+ assert(ctx);
+ assert(channel);
+ assert(attr);
+
+ /*
+ * This value is still used by the kernel consumer since for the kernel,
+ * the stream ownership is not IN the consumer so we need to have the
+ * number of left stream that needs to be initialized so we can know when
+ * to delete the channel (see consumer.c).
+ *
+ * As for the user space tracer now, the consumer creates and sends the
+ * stream to the session daemon which only sends them to the application
+ * once every stream of a channel is received making this value useless
+ * because we they will be added to the poll thread before the application
+ * receives them. This ensures that a stream can not hang up during
+ * initilization of a channel.
+ */
+ channel->nb_init_stream_left = 0;
+
+ /* The reply msg status is handled in the following call. */
+ ret = create_ust_channel(attr, &channel->uchan);
+ if (ret < 0) {
+ goto end;
+ }
+
+ channel->wait_fd = ustctl_channel_get_wait_fd(channel->uchan);
+
+ /*
+ * For the snapshots (no monitor), we create the metadata streams
+ * on demand, not during the channel creation.
+ */
+ if (channel->type == CONSUMER_CHANNEL_TYPE_METADATA && !channel->monitor) {
+ ret = 0;
+ goto end;
+ }
+
+ /* Open all streams for this channel. */
+ ret = create_ust_streams(channel, ctx);
+ if (ret < 0) {
+ goto end;
+ }
+
+end:
+ return ret;
+}
+
+/*
+ * Send all stream of a channel to the right thread handling it.
+ *
+ * On error, return a negative value else 0 on success.
+ */
+static int send_streams_to_thread(struct lttng_consumer_channel *channel,
+ struct lttng_consumer_local_data *ctx)
+{
+ int ret = 0;
+ struct lttng_consumer_stream *stream, *stmp;
+
+ assert(channel);
+ assert(ctx);
+
+ /* Send streams to the corresponding thread. */
+ cds_list_for_each_entry_safe(stream, stmp, &channel->streams.head,
+ send_node) {
+ /* Sending the stream to the thread. */
+ ret = send_stream_to_thread(stream, ctx);
+ if (ret < 0) {
+ /*
+ * If we are unable to send the stream to the thread, there is
+ * a big problem so just stop everything.
+ */
+ /* Remove node from the channel stream list. */
+ cds_list_del(&stream->send_node);
+ goto error;
+ }
+
+ /* Remove node from the channel stream list. */
+ cds_list_del(&stream->send_node);
+
+ }
+
+error:
+ return ret;
+}
+
+/*
+ * Flush channel's streams using the given key to retrieve the channel.
+ *
+ * Return 0 on success else an LTTng error code.
+ */
+static int flush_channel(uint64_t chan_key)
+{
+ int ret = 0;
+ struct lttng_consumer_channel *channel;
+ struct lttng_consumer_stream *stream;
+ struct lttng_ht *ht;
+ struct lttng_ht_iter iter;
+
+ DBG("UST consumer flush channel key %" PRIu64, chan_key);
+
+ rcu_read_lock();
+ channel = consumer_find_channel(chan_key);
+ if (!channel) {
+ ERR("UST consumer flush channel %" PRIu64 " not found", chan_key);
+ ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
+ goto error;
+ }
+
+ ht = consumer_data.stream_per_chan_id_ht;
+
+ /* For each stream of the channel id, flush it. */
+ cds_lfht_for_each_entry_duplicate(ht->ht,
+ ht->hash_fct(&channel->key, lttng_ht_seed), ht->match_fct,
+ &channel->key, &iter.iter, stream, node_channel_id.node) {
+ ustctl_flush_buffer(stream->ustream, 1);
+ }
+error:
+ rcu_read_unlock();
+ return ret;
+}
+/*
+ * Close metadata stream wakeup_fd using the given key to retrieve the channel.
+ * RCU read side lock MUST be acquired before calling this function.
+ *
+ * NOTE: This function does NOT take any channel nor stream lock.
+ *
+ * Return 0 on success else LTTng error code.
+ */
+static int _close_metadata(struct lttng_consumer_channel *channel)
+{
+ int ret = LTTNG_OK;
+
+ assert(channel);
+ assert(channel->type == CONSUMER_CHANNEL_TYPE_METADATA);
+
+ if (channel->switch_timer_enabled == 1) {
+ DBG("Deleting timer on metadata channel");
+ consumer_timer_switch_stop(channel);
+ }
+
+ if (channel->metadata_stream) {
+ ret = ustctl_stream_close_wakeup_fd(channel->metadata_stream->ustream);
+ if (ret < 0) {
+ ERR("UST consumer unable to close fd of metadata (ret: %d)", ret);
+ ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
+ }
+
+ if (channel->monitor) {
+ /* Close the read-side in consumer_del_metadata_stream */
+ ret = close(channel->metadata_stream->ust_metadata_poll_pipe[1]);
+ if (ret < 0) {
+ PERROR("Close UST metadata write-side poll pipe");
+ ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
+ }
+ }
+ }
+
+ return ret;
+}
+
+/*
+ * Close metadata stream wakeup_fd using the given key to retrieve the channel.
+ * RCU read side lock MUST be acquired before calling this function.
+ *
+ * Return 0 on success else an LTTng error code.
+ */
+static int close_metadata(uint64_t chan_key)
+{
+ int ret = 0;
+ struct lttng_consumer_channel *channel;
+
+ DBG("UST consumer close metadata key %" PRIu64, chan_key);
+
+ channel = consumer_find_channel(chan_key);
+ if (!channel) {
+ /*
+ * This is possible if the metadata thread has issue a delete because
+ * the endpoint point of the stream hung up. There is no way the
+ * session daemon can know about it thus use a DBG instead of an actual
+ * error.
+ */
+ DBG("UST consumer close metadata %" PRIu64 " not found", chan_key);
+ ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
+ goto error;
+ }
+
+ pthread_mutex_lock(&consumer_data.lock);
+ pthread_mutex_lock(&channel->lock);
+
+ if (cds_lfht_is_node_deleted(&channel->node.node)) {
+ goto error_unlock;
+ }
+
+ ret = _close_metadata(channel);
+
+error_unlock:
+ pthread_mutex_unlock(&channel->lock);
+ pthread_mutex_unlock(&consumer_data.lock);
+error:
+ return ret;
+}
+
+/*
+ * RCU read side lock MUST be acquired before calling this function.
+ *
+ * Return 0 on success else an LTTng error code.
+ */
+static int setup_metadata(struct lttng_consumer_local_data *ctx, uint64_t key)
+{
+ int ret;
+ struct lttng_consumer_channel *metadata;
+
+ DBG("UST consumer setup metadata key %" PRIu64, key);
+
+ metadata = consumer_find_channel(key);
+ if (!metadata) {
+ ERR("UST consumer push metadata %" PRIu64 " not found", key);
+ ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
+ goto end;
+ }
+
+ /*
+ * In no monitor mode, the metadata channel has no stream(s) so skip the
+ * ownership transfer to the metadata thread.
+ */
+ if (!metadata->monitor) {
+ DBG("Metadata channel in no monitor");
+ ret = 0;
+ goto end;
+ }
+
+ /*
+ * Send metadata stream to relayd if one available. Availability is
+ * known if the stream is still in the list of the channel.
+ */
+ if (cds_list_empty(&metadata->streams.head)) {
+ ERR("Metadata channel key %" PRIu64 ", no stream available.", key);
+ ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
+ goto error_no_stream;
+ }
+
+ /* Send metadata stream to relayd if needed. */
+ if (metadata->metadata_stream->net_seq_idx != (uint64_t) -1ULL) {
+ ret = consumer_send_relayd_stream(metadata->metadata_stream,
+ metadata->pathname);
+ if (ret < 0) {
+ ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
+ goto error;
+ }
+ }
+
+ ret = send_streams_to_thread(metadata, ctx);
+ if (ret < 0) {
+ /*
+ * If we are unable to send the stream to the thread, there is
+ * a big problem so just stop everything.
+ */
+ ret = LTTCOMM_CONSUMERD_FATAL;
+ goto error;
+ }
+ /* List MUST be empty after or else it could be reused. */
+ assert(cds_list_empty(&metadata->streams.head));
+
+ ret = 0;
+ goto end;
+
+error:
+ /*
+ * Delete metadata channel on error. At this point, the metadata stream can
+ * NOT be monitored by the metadata thread thus having the guarantee that
+ * the stream is still in the local stream list of the channel. This call
+ * will make sure to clean that list.
+ */
+ cds_list_del(&metadata->metadata_stream->send_node);
+ consumer_stream_destroy(metadata->metadata_stream, NULL);
+error_no_stream:
+end:
+ return ret;
+}
+
+/*
+ * Snapshot the whole metadata.
+ *
+ * Returns 0 on success, < 0 on error
+ */
+static int snapshot_metadata(uint64_t key, char *path, uint64_t relayd_id,
+ struct lttng_consumer_local_data *ctx)
+{
+ int ret = 0;
+ struct lttng_consumer_channel *metadata_channel;
+ struct lttng_consumer_stream *metadata_stream;
+
+ assert(path);
+ assert(ctx);
+
+ DBG("UST consumer snapshot metadata with key %" PRIu64 " at path %s",
+ key, path);
+
+ rcu_read_lock();
+
+ metadata_channel = consumer_find_channel(key);
+ if (!metadata_channel) {
+ ERR("UST snapshot metadata channel not found for key %" PRIu64,
+ key);
+ ret = -1;
+ goto error;
+ }
+ assert(!metadata_channel->monitor);
+
+ /*
+ * Ask the sessiond if we have new metadata waiting and update the
+ * consumer metadata cache.
+ */
+ ret = lttng_ustconsumer_request_metadata(ctx, metadata_channel, 0, 1);
+ if (ret < 0) {
+ goto error;
+ }
+
+ /*
+ * The metadata stream is NOT created in no monitor mode when the channel
+ * is created on a sessiond ask channel command.
+ */
+ ret = create_ust_streams(metadata_channel, ctx);
+ if (ret < 0) {
+ goto error;
+ }
+
+ metadata_stream = metadata_channel->metadata_stream;
+ assert(metadata_stream);
+
+ if (relayd_id != (uint64_t) -1ULL) {
+ metadata_stream->net_seq_idx = relayd_id;
+ ret = consumer_send_relayd_stream(metadata_stream, path);
+ if (ret < 0) {
+ goto error_stream;
+ }
+ } else {
+ ret = utils_create_stream_file(path, metadata_stream->name,
+ metadata_stream->chan->tracefile_size,
+ metadata_stream->tracefile_count_current,
+ metadata_stream->uid, metadata_stream->gid, NULL);
+ if (ret < 0) {
+ goto error_stream;
+ }
+ metadata_stream->out_fd = ret;
+ metadata_stream->tracefile_size_current = 0;
+ }
+
+ do {
+ ret = lttng_consumer_read_subbuffer(metadata_stream, ctx);
+ if (ret < 0) {
+ goto error_stream;
+ }
+ } while (ret > 0);
+
+error_stream:
+ /*
+ * Clean up the stream completly because the next snapshot will use a new
+ * metadata stream.
+ */
+ cds_list_del(&metadata_stream->send_node);
+ consumer_stream_destroy(metadata_stream, NULL);
+ metadata_channel->metadata_stream = NULL;
+
+error:
+ rcu_read_unlock();
+ return ret;
+}