+ return ustctl_snapshot(stream->ustream);
+}
+
+/*
+ * Sample consumed and produced positions for a specific stream.
+ *
+ * Returns 0 on success, < 0 on error.
+ */
+int lttng_ustconsumer_sample_snapshot_positions(
+ struct lttng_consumer_stream *stream)
+{
+ assert(stream);
+ assert(stream->ustream);
+
+ return ustctl_snapshot_sample_positions(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);
+}
+
+void lttng_ustconsumer_flush_buffer(struct lttng_consumer_stream *stream,
+ int producer)
+{
+ assert(stream);
+ assert(stream->ustream);
+
+ ustctl_flush_buffer(stream->ustream, producer);
+}
+
+int lttng_ustconsumer_get_current_timestamp(
+ struct lttng_consumer_stream *stream, uint64_t *ts)
+{
+ assert(stream);
+ assert(stream->ustream);
+ assert(ts);
+
+ return ustctl_get_current_timestamp(stream->ustream, ts);
+}
+
+int lttng_ustconsumer_get_sequence_number(
+ struct lttng_consumer_stream *stream, uint64_t *seq)
+{
+ assert(stream);
+ assert(stream->ustream);
+ assert(seq);
+
+ return ustctl_get_sequence_number(stream->ustream, seq);
+}
+
+/*
+ * Called when the stream signals the consumer that it has hung up.
+ */
+void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
+{
+ assert(stream);
+ assert(stream->ustream);
+
+ pthread_mutex_lock(&stream->lock);
+ if (!stream->quiescent) {
+ ustctl_flush_buffer(stream->ustream, 0);
+ stream->quiescent = true;
+ }
+ pthread_mutex_unlock(&stream->lock);
+ stream->hangup_flush_done = 1;
+}
+
+void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
+{
+ int i;
+
+ assert(chan);
+ assert(chan->uchan);
+
+ if (chan->switch_timer_enabled == 1) {
+ consumer_timer_switch_stop(chan);
+ }
+ for (i = 0; i < chan->nr_stream_fds; i++) {
+ int ret;
+
+ ret = close(chan->stream_fds[i]);
+ if (ret) {
+ PERROR("close");
+ }
+ if (chan->shm_path[0]) {
+ char shm_path[PATH_MAX];
+
+ ret = get_stream_shm_path(shm_path, chan->shm_path, i);
+ if (ret) {
+ ERR("Cannot get stream shm path");
+ }
+ ret = run_as_unlink(shm_path, chan->uid, chan->gid);
+ if (ret) {
+ PERROR("unlink %s", shm_path);
+ }
+ }
+ }
+}
+
+void lttng_ustconsumer_free_channel(struct lttng_consumer_channel *chan)
+{
+ assert(chan);
+ assert(chan->uchan);
+
+ consumer_metadata_cache_destroy(chan);
+ ustctl_destroy_channel(chan->uchan);
+ /* Try to rmdir all directories under shm_path root. */
+ if (chan->root_shm_path[0]) {
+ (void) run_as_rmdir_recursive(chan->root_shm_path,
+ chan->uid, chan->gid);
+ }
+ free(chan->stream_fds);
+}
+
+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_get_wakeup_fd(struct lttng_consumer_stream *stream)
+{
+ assert(stream);
+ assert(stream->ustream);
+
+ return ustctl_stream_get_wakeup_fd(stream->ustream);
+}
+
+int lttng_ustconsumer_close_wakeup_fd(struct lttng_consumer_stream *stream)
+{
+ assert(stream);
+ assert(stream->ustream);
+
+ return ustctl_stream_close_wakeup_fd(stream->ustream);
+}
+
+/*
+ * Populate index values of a UST stream. Values are set in big endian order.
+ *
+ * Return 0 on success or else a negative value.
+ */
+static int get_index_values(struct ctf_packet_index *index,
+ struct ustctl_consumer_stream *ustream)
+{
+ int ret;
+
+ ret = ustctl_get_timestamp_begin(ustream, &index->timestamp_begin);
+ if (ret < 0) {
+ PERROR("ustctl_get_timestamp_begin");
+ goto error;
+ }
+ index->timestamp_begin = htobe64(index->timestamp_begin);
+
+ ret = ustctl_get_timestamp_end(ustream, &index->timestamp_end);
+ if (ret < 0) {
+ PERROR("ustctl_get_timestamp_end");
+ goto error;
+ }
+ index->timestamp_end = htobe64(index->timestamp_end);
+
+ ret = ustctl_get_events_discarded(ustream, &index->events_discarded);
+ if (ret < 0) {
+ PERROR("ustctl_get_events_discarded");
+ goto error;
+ }
+ index->events_discarded = htobe64(index->events_discarded);
+
+ ret = ustctl_get_content_size(ustream, &index->content_size);
+ if (ret < 0) {
+ PERROR("ustctl_get_content_size");
+ goto error;
+ }
+ index->content_size = htobe64(index->content_size);
+
+ ret = ustctl_get_packet_size(ustream, &index->packet_size);
+ if (ret < 0) {
+ PERROR("ustctl_get_packet_size");
+ goto error;
+ }
+ index->packet_size = htobe64(index->packet_size);
+
+ ret = ustctl_get_stream_id(ustream, &index->stream_id);
+ if (ret < 0) {
+ PERROR("ustctl_get_stream_id");
+ goto error;
+ }
+ index->stream_id = htobe64(index->stream_id);
+
+ ret = ustctl_get_instance_id(ustream, &index->stream_instance_id);
+ if (ret < 0) {
+ PERROR("ustctl_get_instance_id");
+ goto error;
+ }
+ index->stream_instance_id = htobe64(index->stream_instance_id);
+
+ ret = ustctl_get_sequence_number(ustream, &index->packet_seq_num);
+ if (ret < 0) {
+ PERROR("ustctl_get_sequence_number");
+ goto error;
+ }
+ index->packet_seq_num = htobe64(index->packet_seq_num);
+
+error:
+ return ret;
+}
+
+static
+void metadata_stream_reset_cache(struct lttng_consumer_stream *stream,
+ struct consumer_metadata_cache *cache)
+{
+ DBG("Metadata stream update to version %" PRIu64,
+ cache->version);
+ stream->ust_metadata_pushed = 0;
+ stream->metadata_version = cache->version;
+ stream->reset_metadata_flag = 1;
+}
+
+/*
+ * Check if the version of the metadata stream and metadata cache match.
+ * If the cache got updated, reset the metadata stream.
+ * The stream lock and metadata cache lock MUST be held.
+ * Return 0 on success, a negative value on error.
+ */
+static
+int metadata_stream_check_version(struct lttng_consumer_stream *stream)
+{
+ int ret = 0;
+ struct consumer_metadata_cache *cache = stream->chan->metadata_cache;
+
+ if (cache->version == stream->metadata_version) {
+ goto end;
+ }
+ metadata_stream_reset_cache(stream, cache);
+
+end:
+ return ret;
+}
+
+/*
+ * Write up to one packet from the metadata cache to the channel.
+ *
+ * Returns the number of bytes pushed in the cache, or a negative value
+ * on error.
+ */
+static
+int commit_one_metadata_packet(struct lttng_consumer_stream *stream)
+{
+ ssize_t write_len;
+ int ret;
+
+ pthread_mutex_lock(&stream->chan->metadata_cache->lock);
+ ret = metadata_stream_check_version(stream);
+ if (ret < 0) {
+ goto end;
+ }
+ if (stream->chan->metadata_cache->max_offset
+ == 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->max_offset
+ - 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;
+
+ assert(stream->chan->metadata_cache->max_offset >=
+ stream->ust_metadata_pushed);
+ ret = write_len;
+
+end:
+ pthread_mutex_unlock(&stream->chan->metadata_cache->lock);
+ return ret;