+ 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.
+ */
+ goto error;
+ }
+
+ /* Remove node from the channel stream list. */
+ cds_list_del(&stream->send_node);
+
+ /*
+ * From this point on, the stream's ownership has been moved away from
+ * the channel and becomes globally visible.
+ */
+ stream->globally_visible = 1;
+ }
+
+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.
+ *
+ * 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;
+ }
+
+ 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;
+ goto error_unlock;
+ }
+ 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");
+ }
+ }
+ }
+
+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 %lu", 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);
+ 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);
+ if (ret < 0) {
+ goto error_stream;
+ }
+ metadata_stream->out_fd = ret;
+ metadata_stream->tracefile_size_current = 0;
+ }
+
+ pthread_mutex_lock(&metadata_channel->metadata_cache->lock);
+
+ do {
+ ret = lttng_consumer_read_subbuffer(metadata_stream, ctx);
+ if (ret < 0) {
+ goto error_unlock;
+ }
+ } while (ret > 0);
+
+error_unlock:
+ pthread_mutex_unlock(&metadata_channel->metadata_cache->lock);
+
+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;
+}
+
+/*
+ * Take a snapshot of all the stream of a channel.
+ *
+ * Returns 0 on success, < 0 on error
+ */
+static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
+ uint64_t max_stream_size, struct lttng_consumer_local_data *ctx)
+{
+ int ret;
+ unsigned use_relayd = 0;
+ unsigned long consumed_pos, produced_pos;
+ struct lttng_consumer_channel *channel;
+ struct lttng_consumer_stream *stream;
+
+ assert(path);
+ assert(ctx);
+
+ rcu_read_lock();
+
+ if (relayd_id != (uint64_t) -1ULL) {
+ use_relayd = 1;
+ }
+
+ channel = consumer_find_channel(key);
+ if (!channel) {
+ ERR("UST snapshot channel not found for key %lu", key);
+ ret = -1;
+ goto error;
+ }
+ assert(!channel->monitor);
+ DBG("UST consumer snapshot channel %lu", key);
+
+ cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
+ /* Lock stream because we are about to change its state. */
+ pthread_mutex_lock(&stream->lock);
+ stream->net_seq_idx = relayd_id;
+
+ if (use_relayd) {
+ ret = consumer_send_relayd_stream(stream, path);
+ if (ret < 0) {
+ goto error_unlock;
+ }
+ } else {
+ ret = utils_create_stream_file(path, stream->name,
+ stream->chan->tracefile_size,
+ stream->tracefile_count_current,
+ stream->uid, stream->gid);
+ if (ret < 0) {
+ goto error_unlock;
+ }
+ stream->out_fd = ret;
+ stream->tracefile_size_current = 0;
+
+ DBG("UST consumer snapshot stream %s/%s (%" PRIu64 ")", path,
+ stream->name, stream->key);
+ }
+
+ ustctl_flush_buffer(stream->ustream, 1);
+
+ ret = lttng_ustconsumer_take_snapshot(stream);
+ if (ret < 0) {
+ ERR("Taking UST snapshot");
+ goto error_unlock;
+ }
+
+ ret = lttng_ustconsumer_get_produced_snapshot(stream, &produced_pos);
+ if (ret < 0) {
+ ERR("Produced UST snapshot position");
+ goto error_unlock;
+ }
+
+ ret = lttng_ustconsumer_get_consumed_snapshot(stream, &consumed_pos);
+ if (ret < 0) {
+ ERR("Consumerd UST snapshot position");
+ goto error_unlock;
+ }
+
+ /*
+ * The original value is sent back if max stream size is larger than
+ * the possible size of the snapshot. Also, we asume that the session
+ * daemon should never send a maximum stream size that is lower than
+ * subbuffer size.
+ */
+ consumed_pos = consumer_get_consumed_maxsize(consumed_pos,
+ produced_pos, max_stream_size);
+
+ while (consumed_pos < produced_pos) {
+ ssize_t read_len;
+ unsigned long len, padded_len;
+
+ DBG("UST consumer taking snapshot at pos %lu", consumed_pos);
+
+ ret = ustctl_get_subbuf(stream->ustream, &consumed_pos);
+ if (ret < 0) {
+ if (ret != -EAGAIN) {
+ PERROR("ustctl_get_subbuf snapshot");
+ goto error_close_stream;
+ }
+ DBG("UST consumer get subbuf failed. Skipping it.");
+ consumed_pos += stream->max_sb_size;
+ continue;
+ }
+
+ ret = ustctl_get_subbuf_size(stream->ustream, &len);
+ if (ret < 0) {
+ ERR("Snapshot ustctl_get_subbuf_size");
+ goto error_put_subbuf;
+ }
+
+ ret = ustctl_get_padded_subbuf_size(stream->ustream, &padded_len);
+ if (ret < 0) {
+ ERR("Snapshot ustctl_get_padded_subbuf_size");
+ goto error_put_subbuf;
+ }
+
+ read_len = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len,
+ padded_len - len);
+ if (use_relayd) {
+ if (read_len != len) {
+ ret = -1;
+ goto error_put_subbuf;
+ }
+ } else {
+ if (read_len != padded_len) {
+ ret = -1;
+ goto error_put_subbuf;
+ }
+ }
+
+ ret = ustctl_put_subbuf(stream->ustream);
+ if (ret < 0) {
+ ERR("Snapshot ustctl_put_subbuf");
+ goto error_close_stream;
+ }
+ consumed_pos += stream->max_sb_size;
+ }
+
+ /* Simply close the stream so we can use it on the next snapshot. */
+ consumer_stream_close(stream);
+ pthread_mutex_unlock(&stream->lock);
+ }
+
+ rcu_read_unlock();
+ return 0;
+
+error_put_subbuf:
+ if (ustctl_put_subbuf(stream->ustream) < 0) {
+ ERR("Snapshot ustctl_put_subbuf");
+ }
+error_close_stream:
+ consumer_stream_close(stream);
+error_unlock:
+ pthread_mutex_unlock(&stream->lock);
+error:
+ rcu_read_unlock();
+ return ret;
+}
+
+/*
+ * Receive the metadata updates from the sessiond.
+ */
+int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
+ uint64_t len, struct lttng_consumer_channel *channel,
+ int timer)
+{
+ int ret, ret_code = LTTNG_OK;
+ char *metadata_str;
+
+ DBG("UST consumer push metadata key %" PRIu64 " of len %" PRIu64, key, len);
+
+ metadata_str = zmalloc(len * sizeof(char));
+ if (!metadata_str) {
+ PERROR("zmalloc metadata string");
+ ret_code = LTTCOMM_CONSUMERD_ENOMEM;
+ goto end;
+ }
+
+ /* Receive metadata string. */
+ ret = lttcomm_recv_unix_sock(sock, metadata_str, len);
+ if (ret < 0) {
+ /* Session daemon is dead so return gracefully. */
+ ret_code = ret;
+ goto end_free;
+ }
+
+ pthread_mutex_lock(&channel->metadata_cache->lock);
+ ret = consumer_metadata_cache_write(channel, offset, len, metadata_str);
+ if (ret < 0) {
+ /* Unable to handle metadata. Notify session daemon. */
+ ret_code = LTTCOMM_CONSUMERD_ERROR_METADATA;
+ /*
+ * Skip metadata flush on write error since the offset and len might
+ * not have been updated which could create an infinite loop below when
+ * waiting for the metadata cache to be flushed.
+ */
+ pthread_mutex_unlock(&channel->metadata_cache->lock);
+ goto end_free;
+ }
+ pthread_mutex_unlock(&channel->metadata_cache->lock);
+
+ while (consumer_metadata_cache_flushed(channel, offset + len, timer)) {
+ DBG("Waiting for metadata to be flushed");
+ usleep(DEFAULT_METADATA_AVAILABILITY_WAIT_TIME);
+ }
+
+end_free:
+ free(metadata_str);
+end:
+ return ret_code;
+}
+
+/*
+ * Receive command from session daemon and process it.
+ *
+ * Return 1 on success else a negative value or 0.
+ */
+int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
+ int sock, struct pollfd *consumer_sockpoll)
+{
+ ssize_t ret;
+ enum lttng_error_code ret_code = LTTNG_OK;
+ struct lttcomm_consumer_msg msg;
+ struct lttng_consumer_channel *channel = NULL;
+
+ ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
+ if (ret != sizeof(msg)) {
+ DBG("Consumer received unexpected message size %zd (expects %zu)",
+ ret, sizeof(msg));
+ /*
+ * The ret value might 0 meaning an orderly shutdown but this is ok
+ * since the caller handles this.
+ */
+ if (ret > 0) {
+ lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
+ ret = -1;
+ }
+ return ret;
+ }
+ if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
+ /*
+ * Notify the session daemon that the command is completed.
+ *
+ * On transport layer error, the function call will print an error
+ * message so handling the returned code is a bit useless since we
+ * return an error code anyway.
+ */
+ (void) consumer_send_status_msg(sock, ret_code);
+ return -ENOENT;
+ }
+
+ /* relayd needs RCU read-side lock */
+ rcu_read_lock();
+
+ switch (msg.cmd_type) {
+ case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
+ {
+ /* Session daemon status message are handled in the following call. */
+ ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
+ msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
+ &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id);
+ goto end_nosignal;
+ }
+ case LTTNG_CONSUMER_DESTROY_RELAYD:
+ {
+ uint64_t index = msg.u.destroy_relayd.net_seq_idx;
+ struct consumer_relayd_sock_pair *relayd;
+
+ DBG("UST consumer destroying relayd %" PRIu64, index);
+
+ /* Get relayd reference if exists. */
+ relayd = consumer_find_relayd(index);
+ if (relayd == NULL) {
+ DBG("Unable to find relayd %" PRIu64, index);
+ ret_code = LTTNG_ERR_NO_CONSUMER;
+ }
+
+ /*
+ * Each relayd socket pair has a refcount of stream attached to it
+ * which tells if the relayd is still active or not depending on the
+ * refcount value.
+ *
+ * This will set the destroy flag of the relayd object and destroy it
+ * if the refcount reaches zero when called.
+ *
+ * The destroy can happen either here or when a stream fd hangs up.
+ */
+ if (relayd) {
+ consumer_flag_relayd_for_destroy(relayd);
+ }
+
+ goto end_msg_sessiond;
+ }
+ case LTTNG_CONSUMER_UPDATE_STREAM:
+ {
+ rcu_read_unlock();
+ return -ENOSYS;
+ }
+ case LTTNG_CONSUMER_DATA_PENDING:
+ {
+ int ret, is_data_pending;
+ uint64_t id = msg.u.data_pending.session_id;
+
+ DBG("UST consumer data pending command for id %" PRIu64, id);
+
+ is_data_pending = consumer_data_pending(id);
+
+ /* Send back returned value to session daemon */
+ ret = lttcomm_send_unix_sock(sock, &is_data_pending,
+ sizeof(is_data_pending));
+ if (ret < 0) {
+ DBG("Error when sending the data pending ret code: %d", ret);
+ goto error_fatal;
+ }
+
+ /*
+ * No need to send back a status message since the data pending
+ * returned value is the response.
+ */
+ break;
+ }
+ case LTTNG_CONSUMER_ASK_CHANNEL_CREATION:
+ {
+ int ret;
+ struct ustctl_consumer_channel_attr attr;
+
+ /* Create a plain object and reserve a channel key. */
+ channel = allocate_channel(msg.u.ask_channel.session_id,
+ msg.u.ask_channel.pathname, msg.u.ask_channel.name,
+ msg.u.ask_channel.uid, msg.u.ask_channel.gid,
+ msg.u.ask_channel.relayd_id, msg.u.ask_channel.key,
+ (enum lttng_event_output) msg.u.ask_channel.output,
+ msg.u.ask_channel.tracefile_size,
+ msg.u.ask_channel.tracefile_count,
+ msg.u.ask_channel.session_id_per_pid,
+ msg.u.ask_channel.monitor);
+ if (!channel) {
+ goto end_channel_error;
+ }
+
+ /* Build channel attributes from received message. */
+ attr.subbuf_size = msg.u.ask_channel.subbuf_size;
+ attr.num_subbuf = msg.u.ask_channel.num_subbuf;
+ attr.overwrite = msg.u.ask_channel.overwrite;
+ attr.switch_timer_interval = msg.u.ask_channel.switch_timer_interval;
+ attr.read_timer_interval = msg.u.ask_channel.read_timer_interval;
+ attr.chan_id = msg.u.ask_channel.chan_id;
+ attr.output = msg.u.ask_channel.output;
+ memcpy(attr.uuid, msg.u.ask_channel.uuid, sizeof(attr.uuid));
+
+ /* Translate and save channel type. */
+ switch (msg.u.ask_channel.type) {
+ case LTTNG_UST_CHAN_PER_CPU:
+ channel->type = CONSUMER_CHANNEL_TYPE_DATA;
+ attr.type = LTTNG_UST_CHAN_PER_CPU;
+ /*
+ * Set refcount to 1 for owner. Below, we will
+ * pass ownership to the
+ * consumer_thread_channel_poll() thread.
+ */
+ channel->refcount = 1;
+ break;
+ case LTTNG_UST_CHAN_METADATA:
+ channel->type = CONSUMER_CHANNEL_TYPE_METADATA;
+ attr.type = LTTNG_UST_CHAN_METADATA;
+ break;
+ default:
+ assert(0);
+ goto error_fatal;
+ };
+
+ ret = ask_channel(ctx, sock, channel, &attr);
+ if (ret < 0) {
+ goto end_channel_error;
+ }
+
+ if (msg.u.ask_channel.type == LTTNG_UST_CHAN_METADATA) {
+ ret = consumer_metadata_cache_allocate(channel);
+ if (ret < 0) {
+ ERR("Allocating metadata cache");
+ goto end_channel_error;
+ }
+ consumer_timer_switch_start(channel, attr.switch_timer_interval);
+ attr.switch_timer_interval = 0;
+ }
+
+ /*
+ * Add the channel to the internal state AFTER all streams were created
+ * and successfully sent to session daemon. This way, all streams must
+ * be ready before this channel is visible to the threads.
+ * If add_channel succeeds, ownership of the channel is
+ * passed to consumer_thread_channel_poll().
+ */
+ ret = add_channel(channel, ctx);
+ if (ret < 0) {
+ if (msg.u.ask_channel.type == LTTNG_UST_CHAN_METADATA) {
+ if (channel->switch_timer_enabled == 1) {
+ consumer_timer_switch_stop(channel);
+ }
+ consumer_metadata_cache_destroy(channel);
+ }
+ goto end_channel_error;
+ }
+
+ /*
+ * Channel and streams are now created. Inform the session daemon that
+ * everything went well and should wait to receive the channel and
+ * streams with ustctl API.
+ */
+ ret = consumer_send_status_channel(sock, channel);
+ if (ret < 0) {
+ /*
+ * There is probably a problem on the socket.
+ */
+ goto error_fatal;
+ }
+
+ break;
+ }
+ case LTTNG_CONSUMER_GET_CHANNEL:
+ {
+ int ret, relayd_err = 0;
+ uint64_t key = msg.u.get_channel.key;
+ struct lttng_consumer_channel *channel;
+
+ channel = consumer_find_channel(key);
+ if (!channel) {
+ ERR("UST consumer get channel key %" PRIu64 " not found", key);
+ ret_code = LTTNG_ERR_UST_CHAN_NOT_FOUND;
+ goto end_msg_sessiond;
+ }
+
+ /* Send everything to sessiond. */
+ ret = send_sessiond_channel(sock, channel, ctx, &relayd_err);
+ if (ret < 0) {
+ if (relayd_err) {
+ /*
+ * We were unable to send to the relayd the stream so avoid
+ * sending back a fatal error to the thread since this is OK
+ * and the consumer can continue its work. The above call
+ * has sent the error status message to the sessiond.
+ */
+ goto end_nosignal;
+ }
+ /*
+ * The communicaton was broken hence there is a bad state between
+ * the consumer and sessiond so stop everything.
+ */
+ goto error_fatal;
+ }
+
+ /*
+ * In no monitor mode, the streams ownership is kept inside the channel
+ * so don't send them to the data thread.
+ */
+ if (!channel->monitor) {
+ goto end_msg_sessiond;
+ }
+
+ ret = send_streams_to_thread(channel, ctx);
+ if (ret < 0) {
+ /*
+ * If we are unable to send the stream to the thread, there is
+ * a big problem so just stop everything.
+ */
+ goto error_fatal;
+ }
+ /* List MUST be empty after or else it could be reused. */
+ assert(cds_list_empty(&channel->streams.head));
+ goto end_msg_sessiond;
+ }
+ case LTTNG_CONSUMER_DESTROY_CHANNEL:
+ {
+ uint64_t key = msg.u.destroy_channel.key;
+
+ /*
+ * Only called if streams have not been sent to stream
+ * manager thread. However, channel has been sent to
+ * channel manager thread.
+ */
+ notify_thread_del_channel(ctx, key);
+ goto end_msg_sessiond;
+ }
+ case LTTNG_CONSUMER_CLOSE_METADATA:
+ {
+ int ret;
+
+ ret = close_metadata(msg.u.close_metadata.key);
+ if (ret != 0) {
+ ret_code = ret;
+ }
+
+ goto end_msg_sessiond;
+ }
+ case LTTNG_CONSUMER_FLUSH_CHANNEL:
+ {
+ int ret;
+
+ ret = flush_channel(msg.u.flush_channel.key);
+ if (ret != 0) {
+ ret_code = ret;
+ }
+
+ goto end_msg_sessiond;
+ }
+ case LTTNG_CONSUMER_PUSH_METADATA:
+ {
+ int ret;
+ uint64_t len = msg.u.push_metadata.len;
+ uint64_t key = msg.u.push_metadata.key;
+ uint64_t offset = msg.u.push_metadata.target_offset;
+ struct lttng_consumer_channel *channel;
+
+ DBG("UST consumer push metadata key %" PRIu64 " of len %" PRIu64, key,
+ len);
+
+ channel = consumer_find_channel(key);
+ if (!channel) {
+ ERR("UST consumer push metadata %" PRIu64 " not found", key);
+ ret_code = LTTNG_ERR_UST_CHAN_NOT_FOUND;
+ goto end_msg_sessiond;
+ }
+
+ /* Tell session daemon we are ready to receive the metadata. */
+ ret = consumer_send_status_msg(sock, LTTNG_OK);
+ if (ret < 0) {
+ /* Somehow, the session daemon is not responding anymore. */
+ goto error_fatal;
+ }
+
+ /* Wait for more data. */
+ if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
+ goto error_fatal;
+ }
+
+ ret = lttng_ustconsumer_recv_metadata(sock, key, offset,
+ len, channel, 0);
+ if (ret < 0) {
+ /* error receiving from sessiond */
+ goto error_fatal;
+ } else {
+ ret_code = ret;
+ goto end_msg_sessiond;
+ }
+ }
+ case LTTNG_CONSUMER_SETUP_METADATA:
+ {
+ int ret;
+
+ ret = setup_metadata(ctx, msg.u.setup_metadata.key);
+ if (ret) {
+ ret_code = ret;
+ }
+ goto end_msg_sessiond;
+ }
+ case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
+ {
+ if (msg.u.snapshot_channel.metadata) {
+ ret = snapshot_metadata(msg.u.snapshot_channel.key,
+ msg.u.snapshot_channel.pathname,
+ msg.u.snapshot_channel.relayd_id,
+ ctx);
+ if (ret < 0) {
+ ERR("Snapshot metadata failed");
+ ret_code = LTTNG_ERR_UST_META_FAIL;
+ }
+ } else {
+ ret = snapshot_channel(msg.u.snapshot_channel.key,
+ msg.u.snapshot_channel.pathname,
+ msg.u.snapshot_channel.relayd_id,
+ msg.u.snapshot_channel.max_stream_size,
+ ctx);
+ if (ret < 0) {
+ ERR("Snapshot channel failed");
+ ret_code = LTTNG_ERR_UST_CHAN_FAIL;
+ }
+ }
+
+ ret = consumer_send_status_msg(sock, ret_code);
+ if (ret < 0) {
+ /* Somehow, the session daemon is not responding anymore. */
+ goto end_nosignal;
+ }
+ break;
+ }
+ default:
+ break;
+ }
+
+end_nosignal:
+ rcu_read_unlock();
+
+ /*
+ * Return 1 to indicate success since the 0 value can be a socket
+ * shutdown during the recv() or send() call.
+ */
+ return 1;
+
+end_msg_sessiond:
+ /*
+ * The returned value here is not useful since either way we'll return 1 to
+ * the caller because the session daemon socket management is done
+ * elsewhere. Returning a negative code or 0 will shutdown the consumer.
+ */
+ ret = consumer_send_status_msg(sock, ret_code);
+ if (ret < 0) {
+ goto error_fatal;
+ }
+ rcu_read_unlock();
+ return 1;
+end_channel_error:
+ if (channel) {
+ /*
+ * Free channel here since no one has a reference to it. We don't
+ * free after that because a stream can store this pointer.
+ */
+ destroy_channel(channel);
+ }
+ /* We have to send a status channel message indicating an error. */
+ ret = consumer_send_status_channel(sock, NULL);
+ if (ret < 0) {
+ /* Stop everything if session daemon can not be notified. */
+ goto error_fatal;
+ }
+ rcu_read_unlock();
+ return 1;
+error_fatal:
+ rcu_read_unlock();
+ /* This will issue a consumer stop. */
+ return -1;
+}
+
+/*
+ * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
+ * compiled out, we isolate it in this library.
+ */
+int lttng_ustctl_get_mmap_read_offset(struct lttng_consumer_stream *stream,
+ unsigned long *off)
+{
+ assert(stream);
+ assert(stream->ustream);
+
+ return ustctl_get_mmap_read_offset(stream->ustream, off);
+}
+
+/*
+ * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
+ * compiled out, we isolate it in this library.
+ */
+void *lttng_ustctl_get_mmap_base(struct lttng_consumer_stream *stream)
+{
+ assert(stream);
+ assert(stream->ustream);
+
+ return ustctl_get_mmap_base(stream->ustream);
+}
+
+/*
+ * Take a snapshot for a specific fd
+ *
+ * Returns 0 on success, < 0 on error
+ */
+int lttng_ustconsumer_take_snapshot(struct lttng_consumer_stream *stream)
+{
+ assert(stream);
+ assert(stream->ustream);
+
+ return ustctl_snapshot(stream->ustream);
+}
+
+/*
+ * Get the produced position
+ *
+ * Returns 0 on success, < 0 on error
+ */
+int lttng_ustconsumer_get_produced_snapshot(
+ struct lttng_consumer_stream *stream, unsigned long *pos)
+{
+ assert(stream);
+ assert(stream->ustream);
+ assert(pos);
+
+ return ustctl_snapshot_get_produced(stream->ustream, pos);
+}
+
+/*
+ * Get the consumed position
+ *
+ * Returns 0 on success, < 0 on error
+ */
+int lttng_ustconsumer_get_consumed_snapshot(
+ struct lttng_consumer_stream *stream, unsigned long *pos)
+{
+ assert(stream);
+ assert(stream->ustream);
+ assert(pos);
+
+ return ustctl_snapshot_get_consumed(stream->ustream, pos);
+}
+
+/*
+ * Called when the stream signal the consumer that it has hang up.
+ */
+void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
+{
+ assert(stream);
+ assert(stream->ustream);
+
+ ustctl_flush_buffer(stream->ustream, 0);
+ stream->hangup_flush_done = 1;
+}
+
+void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
+{
+ assert(chan);
+ assert(chan->uchan);
+
+ if (chan->switch_timer_enabled == 1) {
+ consumer_timer_switch_stop(chan);
+ }
+ consumer_metadata_cache_destroy(chan);
+ ustctl_destroy_channel(chan->uchan);
+}
+
+void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
+{
+ assert(stream);
+ assert(stream->ustream);
+
+ if (stream->chan->switch_timer_enabled == 1) {
+ consumer_timer_switch_stop(stream->chan);
+ }
+ ustctl_destroy_stream(stream->ustream);
+}
+
+int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
+ struct lttng_consumer_local_data *ctx)
+{
+ unsigned long len, subbuf_size, padding;
+ int err;
+ long ret = 0;
+ char dummy;
+ struct ustctl_consumer_stream *ustream;
+
+ assert(stream);
+ assert(stream->ustream);
+ assert(ctx);
+
+ DBG("In UST read_subbuffer (wait_fd: %d, name: %s)", stream->wait_fd,
+ stream->name);
+
+ /* Ease our life for what's next. */
+ ustream = stream->ustream;
+
+ /* We can consume the 1 byte written into the wait_fd by UST */
+ if (stream->monitor && !stream->hangup_flush_done) {
+ ssize_t readlen;
+
+ do {
+ readlen = read(stream->wait_fd, &dummy, 1);
+ } while (readlen == -1 && errno == EINTR);
+ if (readlen == -1 && errno != EAGAIN && errno != EWOULDBLOCK) {
+ ret = readlen;
+ goto end;
+ }
+ }
+
+retry:
+ /* Get the next subbuffer */
+ err = ustctl_get_next_subbuf(ustream);
+ if (err != 0) {
+ /*
+ * Populate metadata info if the existing info has
+ * already been read.
+ */
+ if (stream->metadata_flag) {
+ ssize_t write_len;
+
+ if (stream->chan->metadata_cache->contiguous
+ == stream->ust_metadata_pushed) {
+ ret = 0;
+ goto end;
+ }
+
+ write_len = ustctl_write_one_packet_to_channel(stream->chan->uchan,
+ &stream->chan->metadata_cache->data[stream->ust_metadata_pushed],
+ stream->chan->metadata_cache->contiguous
+ - stream->ust_metadata_pushed);
+ assert(write_len != 0);
+ if (write_len < 0) {
+ ERR("Writing one metadata packet");
+ ret = -1;
+ goto end;
+ }
+ stream->ust_metadata_pushed += write_len;
+ ustctl_flush_buffer(stream->ustream, 1);
+ goto retry;
+ }
+
+ ret = err; /* ustctl_get_next_subbuf returns negative, caller expect positive. */
+ /*
+ * This is a debug message even for single-threaded consumer,
+ * because poll() have more relaxed criterions than get subbuf,
+ * so get_subbuf may fail for short race windows where poll()
+ * would issue wakeups.
+ */
+ DBG("Reserving sub buffer failed (everything is normal, "
+ "it is due to concurrency) [ret: %d]", err);
+ goto end;
+ }
+ assert(stream->chan->output == CONSUMER_CHANNEL_MMAP);
+ /* Get the full padded subbuffer size */
+ err = ustctl_get_padded_subbuf_size(ustream, &len);
+ assert(err == 0);
+
+ /* Get subbuffer data size (without padding) */
+ err = ustctl_get_subbuf_size(ustream, &subbuf_size);
+ assert(err == 0);
+
+ /* Make sure we don't get a subbuffer size bigger than the padded */
+ assert(len >= subbuf_size);
+
+ padding = len - subbuf_size;
+ /* write the subbuffer to the tracefile */
+ ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding);
+ /*
+ * The mmap operation should write subbuf_size amount of data when network
+ * streaming or the full padding (len) size when we are _not_ streaming.
+ */
+ if ((ret != subbuf_size && stream->net_seq_idx != (uint64_t) -1ULL) ||
+ (ret != len && stream->net_seq_idx == (uint64_t) -1ULL)) {
+ /*
+ * Display the error but continue processing to try to release the
+ * subbuffer. This is a DBG statement since any unexpected kill or
+ * signal, the application gets unregistered, relayd gets closed or
+ * anything that affects the buffer lifetime will trigger this error.
+ * So, for the sake of the user, don't print this error since it can
+ * happen and it is OK with the code flow.
+ */
+ DBG("Error writing to tracefile "
+ "(ret: %ld != len: %lu != subbuf_size: %lu)",
+ ret, len, subbuf_size);
+ }
+ err = ustctl_put_next_subbuf(ustream);
+ assert(err == 0);
+
+end:
+ return ret;
+}
+
+/*
+ * Called when a stream is created.
+ *
+ * Return 0 on success or else a negative value.
+ */
+int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
+{
+ int ret;
+
+ assert(stream);
+
+ /* Don't create anything if this is set for streaming. */
+ if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor) {
+ ret = utils_create_stream_file(stream->chan->pathname, stream->name,
+ stream->chan->tracefile_size, stream->tracefile_count_current,
+ stream->uid, stream->gid);
+ if (ret < 0) {
+ goto error;
+ }
+ stream->out_fd = ret;
+ stream->tracefile_size_current = 0;
+ }
+ ret = 0;
+
+error:
+ return ret;
+}
+
+/*
+ * Check if data is still being extracted from the buffers for a specific
+ * stream. Consumer data lock MUST be acquired before calling this function
+ * and the stream lock.
+ *
+ * Return 1 if the traced data are still getting read else 0 meaning that the
+ * data is available for trace viewer reading.
+ */
+int lttng_ustconsumer_data_pending(struct lttng_consumer_stream *stream)
+{
+ int ret;
+
+ assert(stream);
+ assert(stream->ustream);
+
+ DBG("UST consumer checking data pending");
+
+ if (stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) {
+ ret = 0;
+ goto end;
+ }
+
+ if (stream->chan->type == CONSUMER_CHANNEL_TYPE_METADATA) {
+ /*
+ * We can simply check whether all contiguously available data
+ * has been pushed to the ring buffer, since the push operation
+ * is performed within get_next_subbuf(), and because both
+ * get_next_subbuf() and put_next_subbuf() are issued atomically
+ * thanks to the stream lock within
+ * lttng_ustconsumer_read_subbuffer(). This basically means that
+ * whetnever ust_metadata_pushed is incremented, the associated
+ * metadata has been consumed from the metadata stream.
+ */
+ DBG("UST consumer metadata pending check: contiguous %" PRIu64 " vs pushed %" PRIu64,
+ stream->chan->metadata_cache->contiguous,
+ stream->ust_metadata_pushed);
+ if (stream->chan->metadata_cache->contiguous
+ != stream->ust_metadata_pushed) {
+ ret = 1; /* Data is pending */
+ goto end;
+ }
+ } else {
+ ret = ustctl_get_next_subbuf(stream->ustream);
+ if (ret == 0) {
+ /*
+ * There is still data so let's put back this
+ * subbuffer.
+ */
+ ret = ustctl_put_subbuf(stream->ustream);
+ assert(ret == 0);
+ ret = 1; /* Data is pending */
+ goto end;
+ }
+ }
+
+ /* Data is NOT pending so ready to be read. */
+ ret = 0;
+
+end:
+ return ret;
+}
+
+/*
+ * Close every metadata stream wait fd of the metadata hash table. This
+ * function MUST be used very carefully so not to run into a race between the
+ * metadata thread handling streams and this function closing their wait fd.
+ *
+ * For UST, this is used when the session daemon hangs up. Its the metadata
+ * producer so calling this is safe because we are assured that no state change
+ * can occur in the metadata thread for the streams in the hash table.
+ */
+void lttng_ustconsumer_close_metadata(struct lttng_ht *metadata_ht)
+{
+ int ret;
+ struct lttng_ht_iter iter;
+ struct lttng_consumer_stream *stream;
+
+ assert(metadata_ht);
+ assert(metadata_ht->ht);
+
+ DBG("UST consumer closing all metadata streams");
+
+ rcu_read_lock();
+ cds_lfht_for_each_entry(metadata_ht->ht, &iter.iter, stream,
+ node.node) {
+ int fd = stream->wait_fd;
+
+ /*
+ * Whatever happens here we have to continue to try to close every
+ * streams. Let's report at least the error on failure.
+ */
+ ret = ustctl_stream_close_wakeup_fd(stream->ustream);
+ if (ret) {
+ ERR("Unable to close metadata stream fd %d ret %d", fd, ret);
+ }
+ DBG("Metadata wait fd %d closed", fd);
+ }
+ rcu_read_unlock();
+}
+
+void lttng_ustconsumer_close_stream_wakeup(struct lttng_consumer_stream *stream)
+{
+ int ret;
+
+ ret = ustctl_stream_close_wakeup_fd(stream->ustream);
+ if (ret < 0) {
+ ERR("Unable to close wakeup fd");
+ }
+}
+
+/*
+ * Please refer to consumer-timer.c before adding any lock within this
+ * function or any of its callees. Timers have a very strict locking
+ * semantic with respect to teardown. Failure to respect this semantic
+ * introduces deadlocks.
+ */
+int lttng_ustconsumer_request_metadata(struct lttng_consumer_local_data *ctx,
+ struct lttng_consumer_channel *channel, int timer)
+{
+ struct lttcomm_metadata_request_msg request;
+ struct lttcomm_consumer_msg msg;
+ enum lttng_error_code ret_code = LTTNG_OK;
+ uint64_t len, key, offset;
+ int ret;
+
+ assert(channel);
+ assert(channel->metadata_cache);
+
+ /* send the metadata request to sessiond */
+ switch (consumer_data.type) {
+ case LTTNG_CONSUMER64_UST:
+ request.bits_per_long = 64;
+ break;
+ case LTTNG_CONSUMER32_UST:
+ request.bits_per_long = 32;
+ break;
+ default:
+ request.bits_per_long = 0;
+ break;
+ }
+
+ request.session_id = channel->session_id;
+ request.session_id_per_pid = channel->session_id_per_pid;
+ request.uid = channel->uid;
+ request.key = channel->key;
+ DBG("Sending metadata request to sessiond, session id %" PRIu64
+ ", per-pid %" PRIu64,
+ channel->session_id,
+ channel->session_id_per_pid);
+
+ pthread_mutex_lock(&ctx->metadata_socket_lock);
+ ret = lttcomm_send_unix_sock(ctx->consumer_metadata_socket, &request,
+ sizeof(request));
+ if (ret < 0) {
+ ERR("Asking metadata to sessiond");
+ goto end;
+ }
+
+ /* Receive the metadata from sessiond */
+ ret = lttcomm_recv_unix_sock(ctx->consumer_metadata_socket, &msg,
+ sizeof(msg));
+ if (ret != sizeof(msg)) {
+ DBG("Consumer received unexpected message size %d (expects %zu)",
+ ret, sizeof(msg));
+ lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
+ /*
+ * The ret value might 0 meaning an orderly shutdown but this is ok
+ * since the caller handles this.
+ */
+ goto end;
+ }
+
+ if (msg.cmd_type == LTTNG_ERR_UND) {
+ /* No registry found */
+ (void) consumer_send_status_msg(ctx->consumer_metadata_socket,
+ ret_code);
+ ret = 0;
+ goto end;
+ } else if (msg.cmd_type != LTTNG_CONSUMER_PUSH_METADATA) {
+ ERR("Unexpected cmd_type received %d", msg.cmd_type);
+ ret = -1;
+ goto end;
+ }
+
+ len = msg.u.push_metadata.len;
+ key = msg.u.push_metadata.key;
+ offset = msg.u.push_metadata.target_offset;
+
+ assert(key == channel->key);
+ if (len == 0) {
+ DBG("No new metadata to receive for key %" PRIu64, key);
+ }
+
+ /* Tell session daemon we are ready to receive the metadata. */
+ ret = consumer_send_status_msg(ctx->consumer_metadata_socket,
+ LTTNG_OK);
+ if (ret < 0 || len == 0) {
+ /*
+ * Somehow, the session daemon is not responding anymore or there is
+ * nothing to receive.
+ */
+ goto end;
+ }
+
+ ret_code = lttng_ustconsumer_recv_metadata(ctx->consumer_metadata_socket,
+ key, offset, len, channel, timer);
+ if (ret_code >= 0) {
+ /*
+ * Only send the status msg if the sessiond is alive meaning a positive
+ * ret code.
+ */
+ (void) consumer_send_status_msg(ctx->consumer_metadata_socket, ret_code);
+ }
+ ret = 0;
+
+end:
+ pthread_mutex_unlock(&ctx->metadata_socket_lock);