sessiond: introduce cleared_after_last_stop

[lttng-tools.git] / src / bin / lttng-sessiond / cmd.c

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 7af855eacb14e13b204730cdd2848f888c3bc352..6f824bf316811c2fa486cb4a661abcca5c5b4c3f 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -2636,6 +2636,8 @@ int cmd_start_trace(struct ltt_session *session)
        struct ltt_ust_session *usess;
        const bool session_rotated_after_last_stop =
                        session->rotated_after_last_stop;
+       const bool session_cleared_after_last_stop =
+                       session->cleared_after_last_stop;
 
        assert(session);
 
@@ -2682,6 +2684,7 @@ int cmd_start_trace(struct ltt_session *session)
 
        session->active = 1;
        session->rotated_after_last_stop = false;
+       session->cleared_after_last_stop = false;
        if (session->output_traces && !session->current_trace_chunk) {
                if (!session->has_been_started) {
                        struct lttng_trace_chunk *trace_chunk;
@@ -2770,6 +2773,8 @@ error:
                /* Restore initial state on error. */
                session->rotated_after_last_stop =
                                session_rotated_after_last_stop;
+               session->cleared_after_last_stop =
+                               session_cleared_after_last_stop;
        }
        return ret;
 }
@@ -4967,6 +4972,18 @@ int cmd_rotate_session(struct ltt_session *session,
                cmd_ret = LTTNG_ERR_ROTATION_MULTIPLE_AFTER_STOP;
                goto end;
        }
+
+       /*
+        * After a stop followed by a clear, disallow following rotations a they would
+        * generate empty chunks.
+        */
+       if (session->cleared_after_last_stop) {
+               DBG("Session \"%s\" was already cleared after stop, refusing rotation",
+                               session->name);
+               cmd_ret = LTTNG_ERR_ROTATION_AFTER_STOP_CLEAR;
+               goto end;
+       }
+
        if (session->active) {
                new_trace_chunk = session_create_new_trace_chunk(session, NULL,
                                NULL, NULL);