Cleanup: clarify ownership of excluder

[deliverable/lttng-ust.git] / liblttng-ust / lttng-events.c

diff --git a/liblttng-ust/lttng-events.c b/liblttng-ust/lttng-events.c
index 53bb1100cab922b7fd86a0349c69ce3b057bfb98..fbebc338c6f0b7e49760ff6d6f4dc556f009bd36 100644 (file)
--- a/liblttng-ust/lttng-events.c
+++ b/liblttng-ust/lttng-events.c
@@ -1474,14 +1474,16 @@ int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event
 
 static
 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
-               struct lttng_ust_excluder_node *excluder)
+               struct lttng_ust_excluder_node **excluder)
 {
-       excluder->enabler = enabler;
-       cds_list_add_tail(&excluder->node, &enabler->excluder_head);
+       (*excluder)->enabler = enabler;
+       cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
+       /* Take ownership of excluder */
+       *excluder = NULL;
 }
 
 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
-               struct lttng_ust_excluder_node *excluder)
+               struct lttng_ust_excluder_node **excluder)
 {
        _lttng_enabler_attach_exclusion(
                lttng_event_enabler_as_enabler(event_enabler), excluder);
@@ -1536,7 +1538,7 @@ int lttng_event_notifier_enabler_attach_capture_bytecode(
 
 int lttng_event_notifier_enabler_attach_exclusion(
                struct lttng_event_notifier_enabler *event_notifier_enabler,
-               struct lttng_ust_excluder_node *excluder)
+               struct lttng_ust_excluder_node **excluder)
 {
        _lttng_enabler_attach_exclusion(
                lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
@@ -1708,6 +1710,13 @@ void lttng_session_sync_event_enablers(struct lttng_session *session)
        __tracepoint_probe_prune_release_queue();
 }
 
+/* Support for event notifier is introduced by probe provider major version 2. */
+static
+bool lttng_ust_probe_supports_event_notifier(struct lttng_probe_desc *probe_desc)
+{
+       return probe_desc->major >= 2;
+}
+
 static
 void lttng_create_event_notifier_if_missing(
                struct lttng_event_notifier_enabler *event_notifier_enabler)
@@ -1759,6 +1768,18 @@ void lttng_create_event_notifier_if_missing(
                        if (found)
                                continue;
 
+                       /* Check that the probe supports event notifiers, else report the error. */
+                       if (!lttng_ust_probe_supports_event_notifier(probe_desc)) {
+                               ERR("Probe \"%s\" contains event \"%s\" which matches an enabled event notifier, "
+                                       "but its version (%u.%u) is too old and does not implement event notifiers. "
+                                       "It needs to be recompiled against a newer version of LTTng-UST, otherwise "
+                                       "this event will not generate any notification.",
+                                       probe_desc->provider,
+                                       desc->name,
+                                       probe_desc->major,
+                                       probe_desc->minor);
+                               continue;
+                       }
                        /*
                         * We need to create a event_notifier for this event probe.
                         */