+static
+bool action_type_needs_tracer_notifier(enum lttng_action_type action_type)
+{
+ switch (action_type) {
+ case LTTNG_ACTION_TYPE_NOTIFY:
+ case LTTNG_ACTION_TYPE_START_SESSION:
+ case LTTNG_ACTION_TYPE_STOP_SESSION:
+ case LTTNG_ACTION_TYPE_SNAPSHOT_SESSION:
+ case LTTNG_ACTION_TYPE_ROTATE_SESSION:
+ return true;
+ case LTTNG_ACTION_TYPE_GROUP:
+ case LTTNG_ACTION_TYPE_UNKNOWN:
+ default:
+ abort();
+ }
+}
+
+static
+bool action_needs_tracer_notifier(const struct lttng_action *action)
+{
+ bool needs_tracer_notifier = false;
+ unsigned int i, count;
+ enum lttng_action_status action_status;
+ enum lttng_action_type action_type;
+
+ assert(action);
+ /* If there is only one action. Check if it needs a tracer notifier. */
+ action_type = lttng_action_get_type(action);
+ if (action_type != LTTNG_ACTION_TYPE_GROUP) {
+ needs_tracer_notifier = action_type_needs_tracer_notifier(
+ action_type);
+ goto end;
+ }
+
+ /*
+ * Iterate over all the actions of the action group and check if any of
+ * them needs a tracer notifier.
+ */
+ action_status = lttng_action_group_get_count(action, &count);
+ assert(action_status == LTTNG_ACTION_STATUS_OK);
+ for (i = 0; i < count; i++) {
+ const struct lttng_action *inner_action =
+ lttng_action_group_get_at_index(action, i);
+
+ action_type = lttng_action_get_type(inner_action);
+ if (action_type_needs_tracer_notifier(action_type)) {
+ needs_tracer_notifier = true;
+ goto end;
+ }
+ }
+
+end:
+ return needs_tracer_notifier;
+}
+
+/*
+ * A given trigger needs a tracer notifier if
+ * it has an event-rule condition,
+ * AND
+ * it has one or more sessiond-execution action.
+ */
+static
+bool trigger_needs_tracer_notifier(const struct lttng_trigger *trigger)
+{
+ bool needs_tracer_notifier = false;
+ const struct lttng_condition *condition =
+ lttng_trigger_get_const_condition(trigger);
+ const struct lttng_action *action =
+ lttng_trigger_get_const_action(trigger);
+
+ switch (lttng_condition_get_type(condition)) {
+ case LTTNG_CONDITION_TYPE_ON_EVENT:
+ needs_tracer_notifier = action_needs_tracer_notifier(action);
+ goto end;
+ case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE:
+ case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
+ case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
+ case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING:
+ case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED:
+ goto end;
+ case LTTNG_CONDITION_TYPE_UNKNOWN:
+ default:
+ abort();
+ }
+end:
+ return needs_tracer_notifier;
+}
+