Clean-up: modernize pretty_xml.cpp
[lttng-tools.git] / src / bin / lttng-relayd / live.cpp
index 99037e417c0db58cd76e267383a9f3f7dc1bd068..699778d0e4ef2c144e4bcaba390387750b2f7606 100644 (file)
@@ -238,7 +238,6 @@ static ssize_t send_response(struct lttcomm_sock *sock, void *buf, size_t size)
 static int check_new_streams(struct relay_connection *conn)
 {
        struct relay_session *session;
-       unsigned long current_val;
        int ret = 0;
 
        if (!conn->viewer_session) {
@@ -253,15 +252,19 @@ static int check_new_streams(struct relay_connection *conn)
                        if (!session_get(session)) {
                                continue;
                        }
-                       current_val = uatomic_cmpxchg(&session->new_streams, 1, 0);
-                       ret = current_val;
+
+                       ret = uatomic_read(&session->new_streams);
                        session_put(session);
                        if (ret == 1) {
                                goto end;
                        }
                }
        }
+
 end:
+       DBG("Viewer connection has%s new streams: socket_fd = %d",
+           ret == 0 ? " no" : "",
+           conn->sock->fd);
        return ret;
 }
 
@@ -1218,6 +1221,8 @@ static int viewer_get_new_streams(struct relay_connection *conn)
                response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
                goto send_reply_unlock;
        }
+
+       uatomic_set(&session->new_streams, 0);
        send_streams = 1;
        response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 
@@ -1661,6 +1666,7 @@ static int viewer_get_next_index(struct relay_connection *conn)
        bool viewer_stream_and_session_in_same_chunk, viewer_stream_one_rotation_behind;
        uint64_t stream_file_chunk_id = -1ULL, viewer_session_chunk_id = -1ULL;
        enum lttng_trace_chunk_status status;
+       bool attached_sessions_have_new_streams = false;
 
        LTTNG_ASSERT(conn);
 
@@ -1712,6 +1718,17 @@ static int viewer_get_next_index(struct relay_connection *conn)
                goto send_reply;
        }
 
+       ret = check_new_streams(conn);
+       if (ret < 0) {
+               viewer_index.status = LTTNG_VIEWER_INDEX_ERR;
+               ERR("Error checking for new streams in the attached sessions, returning status=%s",
+                   lttng_viewer_next_index_return_code_str(
+                           (enum lttng_viewer_next_index_return_code) viewer_index.status));
+               goto send_reply;
+       } else if (ret == 1) {
+               attached_sessions_have_new_streams = true;
+       }
+
        if (rstream->ongoing_rotation.is_set) {
                /* Rotation is ongoing, try again later. */
                viewer_index.status = LTTNG_VIEWER_INDEX_RETRY;
@@ -1821,6 +1838,7 @@ static int viewer_get_next_index(struct relay_connection *conn)
                 */
                goto send_reply;
        }
+
        /* At this point, ret is 0 thus we will be able to read the index. */
        LTTNG_ASSERT(!ret);
 
@@ -1899,19 +1917,6 @@ static int viewer_get_next_index(struct relay_connection *conn)
                vstream->stream_file.handle = fs_handle;
        }
 
-       ret = check_new_streams(conn);
-       if (ret < 0) {
-               viewer_index.status = LTTNG_VIEWER_INDEX_ERR;
-               ERR("Error checking for new streams before sending new index to stream id %" PRIu64
-                   ", returning status=%s",
-                   (uint64_t) be64toh(request_index.stream_id),
-                   lttng_viewer_next_index_return_code_str(
-                           (enum lttng_viewer_next_index_return_code) viewer_index.status));
-               goto send_reply;
-       } else if (ret == 1) {
-               viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
-       }
-
        ret = lttng_index_file_read(vstream->index_file, &packet_index);
        if (ret) {
                viewer_index.status = LTTNG_VIEWER_INDEX_ERR;
@@ -1962,6 +1967,10 @@ send_reply:
                pthread_mutex_unlock(&metadata_viewer_stream->stream->lock);
        }
 
+       if (attached_sessions_have_new_streams) {
+               viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
+       }
+
        viewer_index.flags = htobe32(viewer_index.flags);
        viewer_index.status = htobe32(viewer_index.status);
        health_code_update();
@@ -2128,6 +2137,7 @@ static int viewer_get_metadata(struct relay_connection *conn)
        struct lttng_viewer_get_metadata request;
        struct lttng_viewer_metadata_packet reply;
        struct relay_viewer_stream *vstream = nullptr;
+       bool dispose_of_stream = false;
 
        LTTNG_ASSERT(conn);
 
@@ -2156,6 +2166,9 @@ static int viewer_get_metadata(struct relay_connection *conn)
                reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
                goto send_reply;
        }
+
+       pthread_mutex_lock(&vstream->stream->trace->session->lock);
+       pthread_mutex_lock(&vstream->stream->trace->lock);
        pthread_mutex_lock(&vstream->stream->lock);
        if (!vstream->stream->is_metadata) {
                ERR("Invalid metadata stream");
@@ -2164,10 +2177,6 @@ static int viewer_get_metadata(struct relay_connection *conn)
 
        if (vstream->metadata_sent >= vstream->stream->metadata_received) {
                /*
-                * The live viewers expect to receive a NO_NEW_METADATA
-                * status before a stream disappears, otherwise they abort the
-                * entire live connection when receiving an error status.
-                *
                 * Clear feature resets the metadata_received to 0 until the
                 * same metadata is received again.
                 */
@@ -2176,20 +2185,7 @@ static int viewer_get_metadata(struct relay_connection *conn)
                 * The live viewer considers a closed 0 byte metadata stream as
                 * an error.
                 */
-               if (vstream->metadata_sent > 0) {
-                       if (vstream->stream->closed && vstream->stream->no_new_metadata_notified) {
-                               /*
-                                * Release ownership for the viewer metadata
-                                * stream. Note that this reference is the
-                                * viewer's reference. The vstream still exists
-                                * until the end of the function as
-                                * viewer_stream_get_by_id() took a reference.
-                                */
-                               viewer_stream_put(vstream);
-                       }
-
-                       vstream->stream->no_new_metadata_notified = true;
-               }
+               dispose_of_stream = vstream->metadata_sent > 0 && vstream->stream->closed;
                goto send_reply;
        }
 
@@ -2227,6 +2223,19 @@ static int viewer_get_metadata(struct relay_connection *conn)
        len = vstream->stream->metadata_received - vstream->metadata_sent;
 
        if (!vstream->stream_file.trace_chunk) {
+               if (vstream->stream->trace->session->connection_closed) {
+                       /*
+                        * If the connection is closed, there is no way for the metadata stream
+                        * to ever transition back to an active chunk. As such, signal to the viewer
+                        * that there is no new metadata available.
+                        *
+                        * The stream can be disposed-of. On the next execution of this command,
+                        * the relay daemon will reply with an error status since the stream can't
+                        * be found.
+                        */
+                       dispose_of_stream = true;
+               }
+
                reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
                len = 0;
                goto send_reply;
@@ -2357,6 +2366,8 @@ send_reply:
        health_code_update();
        if (vstream) {
                pthread_mutex_unlock(&vstream->stream->lock);
+               pthread_mutex_unlock(&vstream->stream->trace->lock);
+               pthread_mutex_unlock(&vstream->stream->trace->session->lock);
        }
        ret = send_response(conn->sock, &reply, sizeof(reply));
        if (ret < 0) {
@@ -2382,7 +2393,22 @@ end_free:
 end:
        if (vstream) {
                viewer_stream_put(vstream);
+               if (dispose_of_stream) {
+                       /*
+                        * Trigger the destruction of the viewer stream
+                        * by releasing its global reference.
+                        *
+                        * The live viewers expect to receive a NO_NEW_METADATA
+                        * status before a stream disappears, otherwise they abort the
+                        * entire live connection when receiving an error status.
+                        *
+                        * On the next query for this stream, an error will be reported to the
+                        * client.
+                        */
+                       viewer_stream_put(vstream);
+               }
        }
+
        return ret;
 }
 
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