sessiond: add clear notifier

Add a clear notifier array to reply to clients requesting a clear
command.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I422d87b0122b75be47ae5941fed15f09e87460fe
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/bin/lttng-sessiond/session.c b/src/bin/lttng-sessiond/session.c
index 3a537e49e2179357298cb43813dfa17a6f63927d..0da2058fdf28dbbef05f0d2490cfbf49a089a294 100644 (file)
--- a/src/bin/lttng-sessiond/session.c
+++ b/src/bin/lttng-sessiond/session.c
@@ -46,6 +46,11 @@ struct ltt_session_destroy_notifier_element {
        void *user_data;
 };
 
+struct ltt_session_clear_notifier_element {
+       ltt_session_clear_notifier notifier;
+       void *user_data;
+};
+
 /*
  * NOTES:
  *
@@ -769,6 +774,25 @@ void session_notify_destruction(const struct ltt_session *session)
        }
 }
 
+/*
+ * Fire each clear notifier once, and remove them from the array.
+ */
+void session_notify_clear(struct ltt_session *session)
+{
+       size_t i;
+       const size_t count = lttng_dynamic_array_get_count(
+                       &session->clear_notifiers);
+
+       for (i = 0; i < count; i++) {
+               const struct ltt_session_clear_notifier_element *element =
+                       lttng_dynamic_array_get_element(
+                                       &session->clear_notifiers, i);
+
+               element->notifier(session, element->user_data);
+       }
+       lttng_dynamic_array_clear(&session->clear_notifiers);
+}
+
 static
 void session_release(struct urcu_ref *ref)
 {
@@ -831,6 +855,7 @@ void session_release(struct urcu_ref *ref)
                session->ust_session = NULL;
        }
        lttng_dynamic_array_reset(&session->destroy_notifiers);
+       lttng_dynamic_array_reset(&session->clear_notifiers);
        free(session->last_archived_chunk_name);
        free(session->base_path);
        free(session);
@@ -899,6 +924,18 @@ int session_add_destroy_notifier(struct ltt_session *session,
                        &element);
 }
 
+int session_add_clear_notifier(struct ltt_session *session,
+               ltt_session_clear_notifier notifier, void *user_data)
+{
+       const struct ltt_session_clear_notifier_element element = {
+               .notifier = notifier,
+               .user_data = user_data
+       };
+
+       return lttng_dynamic_array_add_element(&session->clear_notifiers,
+                       &element);
+}
+
 /*
  * Return a ltt_session structure ptr that matches name. If no session found,
  * NULL is returned. This must be called with the session list lock held using
@@ -990,6 +1027,9 @@ enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
        lttng_dynamic_array_init(&new_session->destroy_notifiers,
                        sizeof(struct ltt_session_destroy_notifier_element),
                        NULL);
+       lttng_dynamic_array_init(&new_session->clear_notifiers,
+                       sizeof(struct ltt_session_clear_notifier_element),
+                       NULL);
        urcu_ref_init(&new_session->ref);
        pthread_mutex_init(&new_session->lock, NULL);
 
@@ -1184,6 +1224,11 @@ int session_reset_rotation_state(struct ltt_session *session,
                                chunk_id);
                lttng_trace_chunk_put(session->chunk_being_archived);
                session->chunk_being_archived = NULL;
+               /*
+                * Fire the clear reply notifiers if we are completing a clear
+                * rotation.
+                */
+               session_notify_clear(session);
        }
        return ret;
 }

diff --git a/src/bin/lttng-sessiond/session.h b/src/bin/lttng-sessiond/session.h
index a60354d756ca45f0c5885dfdf53c7e473a0bc0b6..da3805658cd28e1255292d6250ae6882f779a6d0 100644 (file)
--- a/src/bin/lttng-sessiond/session.h
+++ b/src/bin/lttng-sessiond/session.h
@@ -36,6 +36,8 @@ struct ltt_ust_session;
 
 typedef void (*ltt_session_destroy_notifier)(const struct ltt_session *session,
                void *user_data);
+typedef void (*ltt_session_clear_notifier)(const struct ltt_session *session,
+               void *user_data);
 
 /*
  * Tracing session list
@@ -193,6 +195,7 @@ struct ltt_session {
        char *last_archived_chunk_name;
        LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id;
        struct lttng_dynamic_array destroy_notifiers;
+       struct lttng_dynamic_array clear_notifiers;
        /* Session base path override. Set non-null. */
        char *base_path;
 };
@@ -210,6 +213,10 @@ void session_destroy(struct ltt_session *session);
 int session_add_destroy_notifier(struct ltt_session *session,
                ltt_session_destroy_notifier notifier, void *user_data);
 
+int session_add_clear_notifier(struct ltt_session *session,
+               ltt_session_clear_notifier notifier, void *user_data);
+void session_notify_clear(struct ltt_session *session);
+
 bool session_get(struct ltt_session *session);
 void session_put(struct ltt_session *session);