sessiond: agent: enable events matching event notifiers

[lttng-tools.git] / src / bin / lttng-sessiond / agent.h

diff --git a/src/bin/lttng-sessiond/agent.h b/src/bin/lttng-sessiond/agent.h
index f8e67efdae82b7130e951d721859841991fa2e76..e82f32627937c162b26464ac1024815750b7e0f3 100644 (file)
--- a/src/bin/lttng-sessiond/agent.h
+++ b/src/bin/lttng-sessiond/agent.h
@@ -24,11 +24,15 @@
  */
 extern struct lttng_ht *agent_apps_ht_by_sock;
 
+/*
+ * Hash table that contains the trigger agents by domain */
+extern struct lttng_ht *trigger_agents_ht_by_domain;
+
 struct agent_ht_key {
        const char *name;
        int loglevel_value;
        enum lttng_loglevel_type loglevel_type;
-       char *filter_expression;
+       const char *filter_expression;
 };
 
 /*
@@ -68,6 +72,7 @@ struct agent_app {
 
 /*
  * Agent event representation.
+ * Accesses to this structure are protected by the session list lock.
  */
 struct agent_event {
        /* Name of the event. */
@@ -76,9 +81,18 @@ struct agent_event {
        enum lttng_loglevel_type loglevel_type;
 
        /*
-        * Tells if the event is enabled or not on the agent.
+        * Tells if the event is enabled or not on the agent. While this can be
+        * implicitly tested as a boolean, it is in fact a reference count and
+        * the AGENT_EVENT_IS_ENABLED macro should be used to prevent accidental
+        * comparisons to non-zero literals (e.g. '1').
+        *
+        * Multiple triggers and events can map to the same agent event as it
+        * is merely a "filter" in front of a user space tracer enabler.
+        *
+        * This count is updated to ensure an event is only disabled when all
+        * matching enablers are disabled.
         */
-       unsigned int enabled:1;
+       unsigned int enabled_count;
 
        /* Hash table node of the agent domain object. */
        struct lttng_ht_node_str node;
@@ -89,8 +103,12 @@ struct agent_event {
        struct lttng_event_exclusion *exclusion;
 };
 
+#define AGENT_EVENT_IS_ENABLED(agent_event) (!!agent_event->enabled_count)
+
 /*
- * Agent object containing events enabled/disabled for it.
+ * Agent object containing events enabled/disabled for a given domain in a
+ * scope. The scope is typically a session, but can also be "global" in the
+ * context of event notifiers: see event_notifiers_find_agent().
  */
 struct agent {
        /*
@@ -133,8 +151,10 @@ struct agent_event *agent_create_event(const char *name,
 void agent_add_event(struct agent_event *event, struct agent *agt);
 
 struct agent_event *agent_find_event(const char *name,
-               enum lttng_loglevel_type loglevel_type, int loglevel_value,
-               char *filter_expression, struct agent *agt);
+               enum lttng_loglevel_type loglevel_type,
+               int loglevel_value,
+               const char *filter_expression,
+               struct agent *agt);
 void agent_find_events_by_name(const char *name, struct agent *agt,
                struct lttng_ht_iter* iter);
 void agent_event_next_duplicate(const char *name,
@@ -167,4 +187,13 @@ void agent_update(const struct agent *agt, const struct agent_app *app);
 int agent_list_events(struct lttng_event **events,
                enum lttng_domain_type domain);
 
+struct agent_event *agent_find_event_by_trigger(
+               const struct lttng_trigger *trigger, struct agent *agt);
+
+/* Global event notifier per-domain agents. */
+struct agent *agent_find_by_event_notifier_domain(
+               enum lttng_domain_type domain_type);
+void agent_by_event_notifier_domain_ht_destroy(void);
+int agent_by_event_notifier_domain_ht_create(void);
+
 #endif /* LTTNG_SESSIOND_AGENT_H */