Fix: relayd: viewer metadata is not rotated after a session clear

[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 5f9c7c5769f799d5ff101446b730b06c340b5f4f..0b77fd144c6a58e407edc7118a450eb8a6cf7848 100644 (file)
--- a/src/bin/lttng-relayd/viewer-session.c
+++ b/src/bin/lttng-relayd/viewer-session.c
@@ -1,20 +1,10 @@
 /*
- * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
- *                      David Goulet <dgoulet@efficios.com>
- *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
+ * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License, version 2 only, as
- * published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 51
- * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #define _LGPL_SOURCE
@@ -41,26 +31,69 @@ end:
        return vsession;
 }
 
+int viewer_session_set_trace_chunk_copy(struct relay_viewer_session *vsession,
+               struct lttng_trace_chunk *relay_session_trace_chunk)
+{
+       int ret = 0;
+       struct lttng_trace_chunk *viewer_chunk;
+
+       assert(relay_session_trace_chunk);
+       lttng_trace_chunk_put(vsession->current_trace_chunk);
+       vsession->current_trace_chunk = NULL;
+
+       DBG("Copying relay session's current trace chunk to the viewer session");
+       viewer_chunk = lttng_trace_chunk_copy(relay_session_trace_chunk);
+       if (!viewer_chunk) {
+               ERR("Failed to create a viewer trace chunk from the relay session's current chunk");
+               ret = -1;
+               goto end;
+       }
+
+       vsession->current_trace_chunk = viewer_chunk;
+end:
+       return ret;
+}
+
 /* 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_copy(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 +104,7 @@ 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. */
@@ -101,6 +134,7 @@ static int viewer_session_detach(struct relay_viewer_session *vsession,
 
 void viewer_session_destroy(struct relay_viewer_session *vsession)
 {
+       lttng_trace_chunk_put(vsession->current_trace_chunk);
        free(vsession);
 }
 
@@ -135,7 +169,8 @@ void viewer_session_close_one_session(struct relay_viewer_session *vsession,
                 */
                viewer_stream_put(vstream);
        }
-
+       lttng_trace_chunk_put(vsession->current_trace_chunk);
+       vsession->current_trace_chunk = NULL;
        viewer_session_detach(vsession, session);
 }