Fix: relayd: session trace chunk is copied too late

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

diff --git a/src/bin/lttng-relayd/viewer-session.c b/src/bin/lttng-relayd/viewer-session.c
index 7ff58ed967842b75881a43c7de4fa5f029cc23fe..d394465ba1c51d3f1575ed7630c2f6dc4c942908 100644 (file)
--- a/src/bin/lttng-relayd/viewer-session.c
+++ b/src/bin/lttng-relayd/viewer-session.c
@@ -42,25 +42,45 @@ end:
 }
 
 /* The existence of session must be guaranteed by the caller. */
-int viewer_session_attach(struct relay_viewer_session *vsession,
+enum lttng_viewer_attach_return_code viewer_session_attach(
+               struct relay_viewer_session *vsession,
                struct relay_session *session)
 {
-       int ret = 0;
+       enum lttng_viewer_attach_return_code viewer_attach_status =
+                       LTTNG_VIEWER_ATTACH_OK;
 
        ASSERT_LOCKED(session->lock);
 
        /* Will not fail, as per the ownership guarantee. */
        if (!session_get(session)) {
-               ret = -1;
+               viewer_attach_status = LTTNG_VIEWER_ATTACH_UNK;
                goto end;
        }
        if (session->viewer_attached) {
-               ret = -1;
+               viewer_attach_status = LTTNG_VIEWER_ATTACH_ALREADY;
        } else {
+               int ret;
+
+               assert(session->current_trace_chunk);
+               assert(!vsession->current_trace_chunk);
                session->viewer_attached = true;
+
+               ret = viewer_session_set_trace_chunk(vsession,
+                               session->current_trace_chunk);
+               if (ret) {
+                       /*
+                        * The live protocol does not define a generic error
+                        * value for the "attach" command. The "unknown"
+                        * status is used so that the viewer may handle this
+                        * failure as if the session didn't exist anymore.
+                        */
+                       DBG("Failed to create a viewer trace chunk from the current trace chunk of session \"%s\", returning LTTNG_VIEWER_ATTACH_UNK",
+                                       session->session_name);
+                       viewer_attach_status = LTTNG_VIEWER_ATTACH_UNK;
+               }
        }
 
-       if (!ret) {
+       if (viewer_attach_status == LTTNG_VIEWER_ATTACH_OK) {
                pthread_mutex_lock(&vsession->session_list_lock);
                /* Ownership is transfered to the list. */
                cds_list_add_rcu(&session->viewer_session_node,
@@ -71,7 +91,7 @@ int viewer_session_attach(struct relay_viewer_session *vsession,
                session_put(session);
        }
 end:
-       return ret;
+       return viewer_attach_status;
 }
 
 /* The existence of session must be guaranteed by the caller. */