Fix: relayd: live: mishandled initial null trace chunk

[lttng-tools.git] / src / bin / lttng-relayd / live.c

diff --git a/src/bin/lttng-relayd/live.c b/src/bin/lttng-relayd/live.c
index 42b0d947e2072881662a5024a589409db6766d19..962fe0fd14a340c9e903f6410d09b1b6f386a3de 100644 (file)
--- a/src/bin/lttng-relayd/live.c
+++ b/src/bin/lttng-relayd/live.c
@@ -384,8 +384,6 @@ static int make_viewer_streams(struct relay_session *relay_session,
                                                goto error_unlock;
                                        }
                                } else {
-                                       bool reference_acquired;
-
                                        /*
                                         * Transition the viewer session into the newest trace chunk available.
                                         */
@@ -402,11 +400,26 @@ static int make_viewer_streams(struct relay_session *relay_session,
                                                }
                                        }
 
-                                       reference_acquired = lttng_trace_chunk_get(
-                                                       viewer_session->current_trace_chunk);
-                                       LTTNG_ASSERT(reference_acquired);
-                                       viewer_stream_trace_chunk =
-                                                       viewer_session->current_trace_chunk;
+                                       if (relay_stream->trace_chunk) {
+                                               /*
+                                                * If the corresponding relay
+                                                * stream's trace chunk is set,
+                                                * the viewer stream will be
+                                                * created under it.
+                                                *
+                                                * Note that a relay stream can
+                                                * have a NULL output trace
+                                                * chunk (for instance, after a
+                                                * clear against a stopped
+                                                * session).
+                                                */
+                                               const bool reference_acquired = lttng_trace_chunk_get(
+                                                               viewer_session->current_trace_chunk);
+
+                                               LTTNG_ASSERT(reference_acquired);
+                                               viewer_stream_trace_chunk =
+                                                               viewer_session->current_trace_chunk;
+                                       }
                                }
 
                                viewer_stream = viewer_stream_create(
@@ -2016,8 +2029,9 @@ int viewer_get_metadata(struct relay_connection *conn)
                }
        }
 
-       if (conn->viewer_session->current_trace_chunk !=
-                       vstream->stream_file.trace_chunk) {
+       if (conn->viewer_session->current_trace_chunk &&
+                       conn->viewer_session->current_trace_chunk !=
+                                       vstream->stream_file.trace_chunk) {
                bool acquired_reference;
 
                DBG("Viewer session and viewer stream chunk differ: "
@@ -2034,11 +2048,16 @@ int viewer_get_metadata(struct relay_connection *conn)
 
        len = vstream->stream->metadata_received - vstream->metadata_sent;
 
-       /*
-        * Either this is the first time the metadata file is read, or a
-        * rotation of the corresponding relay stream has occurred.
-        */
-       if (!vstream->stream_file.handle && len > 0) {
+       if (!vstream->stream_file.trace_chunk) {
+               reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
+               len = 0;
+               goto send_reply;
+       } else if (vstream->stream_file.trace_chunk &&
+                       !vstream->stream_file.handle && len > 0) {
+               /*
+                * Either this is the first time the metadata file is read, or a
+                * rotation of the corresponding relay stream has occurred.
+                */
                struct fs_handle *fs_handle;
                char file_path[LTTNG_PATH_MAX];
                enum lttng_trace_chunk_status status;