Fix: handle new streams in live mode in relayd
[lttng-tools.git] / src / bin / lttng-relayd / live.c
index 1a691a849c11e972fee17059df4d5c7068846f01..69e2eb3b286c2f54cad19fefbdbe1e5f2bb93492 100644 (file)
@@ -852,6 +852,166 @@ error:
        return ret;
 }
 
+/*
+ * Send the viewer the list of current sessions.
+ */
+static
+int viewer_get_new_streams(struct relay_command *cmd,
+               struct lttng_ht *sessions_ht)
+{
+       int ret, send_streams = 0;
+       uint32_t nb_streams = 0;
+       struct lttng_viewer_new_streams_request request;
+       struct lttng_viewer_new_streams_response response;
+       struct lttng_viewer_stream send_stream;
+       struct relay_stream *stream;
+       struct relay_viewer_stream *viewer_stream;
+       struct lttng_ht_node_ulong *node;
+       struct lttng_ht_iter iter;
+       struct relay_session *session;
+
+       assert(cmd);
+       assert(sessions_ht);
+
+       DBG("Get new streams received");
+
+       if (cmd->version_check_done == 0) {
+               ERR("Trying to get streams before version check");
+               ret = -1;
+               goto end_no_session;
+       }
+
+       health_code_update();
+
+       ret = cmd->sock->ops->recvmsg(cmd->sock, &request, sizeof(request), 0);
+       if (ret < 0 || ret != sizeof(request)) {
+               if (ret == 0) {
+                       /* Orderly shutdown. Not necessary to print an error. */
+                       DBG("Socket %d did an orderly shutdown", cmd->sock->fd);
+               } else {
+                       ERR("Relay failed to receive the command parameters.");
+               }
+               ret = -1;
+               goto error;
+       }
+
+       health_code_update();
+
+       rcu_read_lock();
+       lttng_ht_lookup(sessions_ht,
+                       (void *)((unsigned long) be64toh(request.session_id)), &iter);
+       node = lttng_ht_iter_get_node_ulong(&iter);
+       if (node == NULL) {
+               DBG("Relay session %" PRIu64 " not found",
+                               be64toh(request.session_id));
+               response.status = htobe32(VIEWER_NEW_STREAMS_ERR);
+               goto send_reply;
+       }
+
+       session = caa_container_of(node, struct relay_session, session_n);
+       if (cmd->session_id == session->id) {
+               /* We confirmed the viewer is asking for the same session. */
+               send_streams = 1;
+               response.status = htobe32(VIEWER_NEW_STREAMS_OK);
+       } else {
+               send_streams = 0;
+               response.status = htobe32(VIEWER_NEW_STREAMS_ERR);
+               goto send_reply;
+       }
+
+       /*
+        * Fill the viewer_streams_ht to count the number of streams ready to be
+        * sent and avoid concurrency issues on the relay_streams_ht and don't rely
+        * on a total session stream count.
+        */
+       pthread_mutex_lock(&session->viewer_ready_lock);
+       cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, stream,
+                       stream_n.node) {
+               struct relay_viewer_stream *vstream;
+
+               health_code_update();
+
+               /*
+                * Don't send stream if no ctf_trace, wrong session or if the stream is
+                * not ready for the viewer.
+                */
+               if (stream->session != cmd->session ||
+                               !stream->ctf_trace || !stream->viewer_ready) {
+                       continue;
+               }
+
+               vstream = live_find_viewer_stream_by_id(stream->stream_handle);
+               if (!vstream) {
+                       ret = init_viewer_stream(stream, 0);
+                       if (ret < 0) {
+                               pthread_mutex_unlock(&session->viewer_ready_lock);
+                               goto end_unlock;
+                       }
+                       nb_streams++;
+               } else if (!vstream->sent_flag) {
+                       nb_streams++;
+               }
+       }
+       pthread_mutex_unlock(&session->viewer_ready_lock);
+
+       response.streams_count = htobe32(nb_streams);
+
+send_reply:
+       health_code_update();
+       ret = cmd->sock->ops->sendmsg(cmd->sock, &response, sizeof(response), 0);
+       if (ret < 0) {
+               ERR("Relay sending viewer attach response");
+               goto end_unlock;
+       }
+       health_code_update();
+
+       /*
+        * Unknown or empty session, just return gracefully, the viewer knows what
+        * is happening.
+        */
+       if (!send_streams || !nb_streams) {
+               ret = 0;
+               goto end_unlock;
+       }
+
+       /* We should only be there if we have a session to attach to. */
+       cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, viewer_stream,
+                       stream_n.node) {
+               health_code_update();
+
+               /* Don't send back if session does not match or already sent. */
+               if (viewer_stream->session_id != cmd->session->id ||
+                               viewer_stream->sent_flag) {
+                       continue;
+               }
+
+               send_stream.id = htobe64(viewer_stream->stream_handle);
+               send_stream.ctf_trace_id = htobe64(viewer_stream->ctf_trace->id);
+               send_stream.metadata_flag = htobe32(viewer_stream->metadata_flag);
+               strncpy(send_stream.path_name, viewer_stream->path_name,
+                               sizeof(send_stream.path_name));
+               strncpy(send_stream.channel_name, viewer_stream->channel_name,
+                               sizeof(send_stream.channel_name));
+
+               ret = cmd->sock->ops->sendmsg(cmd->sock, &send_stream,
+                               sizeof(send_stream), 0);
+               if (ret < 0) {
+                       ERR("Relay sending stream %" PRIu64, viewer_stream->stream_handle);
+                       goto end_unlock;
+               }
+               DBG("Sent stream %" PRIu64 " to viewer", viewer_stream->stream_handle);
+               viewer_stream->sent_flag = 1;
+       }
+
+       ret = 0;
+
+end_unlock:
+       rcu_read_unlock();
+end_no_session:
+error:
+       return ret;
+}
+
 /*
  * Send the viewer the list of current sessions.
  */
@@ -860,7 +1020,7 @@ int viewer_attach_session(struct relay_command *cmd,
                struct lttng_ht *sessions_ht)
 {
        int ret, send_streams = 0;
-       uint32_t nb_streams = 0, nb_streams_ready = 0;
+       uint32_t nb_streams = 0;
        struct lttng_viewer_attach_session_request request;
        struct lttng_viewer_attach_session_response response;
        struct lttng_viewer_stream send_stream;
@@ -954,6 +1114,7 @@ int viewer_attach_session(struct relay_command *cmd,
                 * ready to be sent and avoid concurrency issues on the
                 * relay_streams_ht and don't rely on a total session stream count.
                 */
+               pthread_mutex_lock(&session->viewer_ready_lock);
                cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, node, node) {
                        struct relay_viewer_stream *vstream;
 
@@ -967,7 +1128,6 @@ int viewer_attach_session(struct relay_command *cmd,
                        if (stream->session != cmd->session) {
                                continue;
                        }
-                       nb_streams++;
 
                        /*
                         * Don't send streams with no ctf_trace, they are not
@@ -976,21 +1136,19 @@ int viewer_attach_session(struct relay_command *cmd,
                        if (!stream->ctf_trace || !stream->viewer_ready) {
                                continue;
                        }
-                       nb_streams_ready++;
 
                        vstream = live_find_viewer_stream_by_id(stream->stream_handle);
                        if (!vstream) {
                                ret = init_viewer_stream(stream, seek_last);
                                if (ret < 0) {
+                                       pthread_mutex_unlock(&session->viewer_ready_lock);
                                        goto end_unlock;
                                }
                        }
+                       nb_streams++;
                }
+               pthread_mutex_unlock(&session->viewer_ready_lock);
 
-               /* We must have the same amount of existing stream and ready stream. */
-               if (nb_streams != nb_streams_ready) {
-                       nb_streams = 0;
-               }
                response.streams_count = htobe32(nb_streams);
        }
 
@@ -1042,6 +1200,7 @@ send_reply:
                        goto end_unlock;
                }
                DBG("Sent stream %" PRIu64 " to viewer", viewer_stream->stream_handle);
+               viewer_stream->sent_flag = 1;
        }
        ret = 0;
 
@@ -1719,6 +1878,9 @@ int process_control(struct lttng_viewer_cmd *recv_hdr,
        case VIEWER_GET_METADATA:
                ret = viewer_get_metadata(cmd);
                break;
+       case VIEWER_GET_NEW_STREAMS:
+               ret = viewer_get_new_streams(cmd, sessions_ht);
+               break;
        default:
                ERR("Received unknown viewer command (%u)", be32toh(recv_hdr->cmd));
                live_relay_unknown_command(cmd);
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