+/*
+ * Populate index values of a kernel 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, int infd)
+{
+ int ret;
+
+ ret = kernctl_get_timestamp_begin(infd, &index->timestamp_begin);
+ if (ret < 0) {
+ PERROR("kernctl_get_timestamp_begin");
+ goto error;
+ }
+ index->timestamp_begin = htobe64(index->timestamp_begin);
+
+ ret = kernctl_get_timestamp_end(infd, &index->timestamp_end);
+ if (ret < 0) {
+ PERROR("kernctl_get_timestamp_end");
+ goto error;
+ }
+ index->timestamp_end = htobe64(index->timestamp_end);
+
+ ret = kernctl_get_events_discarded(infd, &index->events_discarded);
+ if (ret < 0) {
+ PERROR("kernctl_get_events_discarded");
+ goto error;
+ }
+ index->events_discarded = htobe64(index->events_discarded);
+
+ ret = kernctl_get_content_size(infd, &index->content_size);
+ if (ret < 0) {
+ PERROR("kernctl_get_content_size");
+ goto error;
+ }
+ index->content_size = htobe64(index->content_size);
+
+ ret = kernctl_get_packet_size(infd, &index->packet_size);
+ if (ret < 0) {
+ PERROR("kernctl_get_packet_size");
+ goto error;
+ }
+ index->packet_size = htobe64(index->packet_size);
+
+ ret = kernctl_get_stream_id(infd, &index->stream_id);
+ if (ret < 0) {
+ PERROR("kernctl_get_stream_id");
+ goto error;
+ }
+ index->stream_id = htobe64(index->stream_id);
+
+error:
+ return ret;
+}
+/*
+ * Sync metadata meaning request them to the session daemon and snapshot to the
+ * metadata thread can consumer them.
+ *
+ * Metadata stream lock MUST be acquired.
+ *
+ * Return 0 if new metadatda is available, EAGAIN if the metadata stream
+ * is empty or a negative value on error.
+ */
+int lttng_kconsumer_sync_metadata(struct lttng_consumer_stream *metadata)
+{
+ int ret;
+
+ assert(metadata);
+
+ ret = kernctl_buffer_flush(metadata->wait_fd);
+ if (ret < 0) {
+ ERR("Failed to flush kernel stream");
+ goto end;
+ }
+
+ ret = kernctl_snapshot(metadata->wait_fd);
+ if (ret < 0) {
+ if (errno != EAGAIN) {
+ ERR("Sync metadata, taking kernel snapshot failed.");
+ goto end;
+ }
+ DBG("Sync metadata, no new kernel metadata");
+ /* No new metadata, exit. */
+ ret = ENODATA;
+ goto end;
+ }
+
+end:
+ return ret;
+}
+
+static
+int update_stream_stats(struct lttng_consumer_stream *stream)
+{
+ int ret;
+ uint64_t seq, discarded;
+
+ ret = kernctl_get_sequence_number(stream->wait_fd, &seq);
+ if (ret < 0) {
+ PERROR("kernctl_get_sequence_number");
+ goto end;
+ }
+
+ /*
+ * Start the sequence when we extract the first packet in case we don't
+ * start at 0 (for example if a consumer is not connected to the
+ * session immediately after the beginning).
+ */
+ if (stream->last_sequence_number == -1ULL) {
+ stream->last_sequence_number = seq;
+ } else if (seq > stream->last_sequence_number) {
+ stream->chan->lost_packets += seq -
+ stream->last_sequence_number - 1;
+ } else {
+ /* seq <= last_sequence_number */
+ ERR("Sequence number inconsistent : prev = %" PRIu64
+ ", current = %" PRIu64,
+ stream->last_sequence_number, seq);
+ ret = -1;
+ goto end;
+ }
+ stream->last_sequence_number = seq;
+
+ ret = kernctl_get_events_discarded(stream->wait_fd, &discarded);
+ if (ret < 0) {
+ PERROR("kernctl_get_events_discarded");
+ goto end;
+ }
+ if (discarded < stream->last_discarded_events) {
+ /*
+ * Overflow has occured. We assume only one wrap-around
+ * has occured.
+ */
+ stream->chan->discarded_events += (1ULL << (CAA_BITS_PER_LONG - 1)) -
+ stream->last_discarded_events + discarded;
+ } else {
+ stream->chan->discarded_events += discarded -
+ stream->last_discarded_events;
+ }
+ stream->last_discarded_events = discarded;
+ ret = 0;
+
+end:
+ return ret;
+}
+