sessiond: setup event notifier group for registering app
[lttng-tools.git] / src / bin / lttng-sessiond / ust-app.c
index b07bf684bcf870c59a2a212712ffec25db037af4..b30089dbc2fd6029f590adf8c05752ddda2d3225 100644 (file)
@@ -921,6 +921,28 @@ void delete_ust_app(struct ust_app *app)
        ht_cleanup_push(app->ust_sessions_objd);
        ht_cleanup_push(app->ust_objd);
 
+       /*
+        * This could be NULL if the event notifier setup failed (e.g the app
+        * was killed or the tracer does not support this feature).
+        */
+       if (app->event_notifier_group.object) {
+               enum lttng_error_code ret_code;
+               const int event_notifier_read_fd = lttng_pipe_get_readfd(
+                               app->event_notifier_group.event_pipe);
+
+               ret_code = notification_thread_command_remove_tracer_event_source(
+                               notification_thread_handle,
+                               event_notifier_read_fd);
+               if (ret_code != LTTNG_OK) {
+                       ERR("Failed to remove application tracer event source from notification thread");
+               }
+
+               ustctl_release_object(sock, app->event_notifier_group.object);
+               free(app->event_notifier_group.object);
+       }
+
+       lttng_pipe_destroy(app->event_notifier_group.event_pipe);
+
        /*
         * Wait until we have deleted the application from the sock hash table
         * before closing this socket, otherwise an application could re-use the
@@ -3312,6 +3334,7 @@ error:
 struct ust_app *ust_app_create(struct ust_register_msg *msg, int sock)
 {
        struct ust_app *lta = NULL;
+       struct lttng_pipe *event_notifier_event_source_pipe = NULL;
 
        assert(msg);
        assert(sock >= 0);
@@ -3328,12 +3351,21 @@ struct ust_app *ust_app_create(struct ust_register_msg *msg, int sock)
                goto error;
        }
 
+       event_notifier_event_source_pipe = lttng_pipe_open(FD_CLOEXEC);
+       if (!event_notifier_event_source_pipe) {
+               PERROR("Failed to open application event source pipe: '%s' (ppid = %d)",
+                               msg->name, msg->ppid);
+               goto error;
+       }
+
        lta = zmalloc(sizeof(struct ust_app));
        if (lta == NULL) {
                PERROR("malloc");
-               goto error;
+               goto error_free_pipe;
        }
 
+       lta->event_notifier_group.event_pipe = event_notifier_event_source_pipe;
+
        lta->ppid = msg->ppid;
        lta->uid = msg->uid;
        lta->gid = msg->gid;
@@ -3371,8 +3403,12 @@ struct ust_app *ust_app_create(struct ust_register_msg *msg, int sock)
        lttng_ht_node_init_ulong(&lta->sock_n, (unsigned long) lta->sock);
 
        CDS_INIT_LIST_HEAD(&lta->teardown_head);
-error:
        return lta;
+
+error_free_pipe:
+       lttng_pipe_destroy(event_notifier_event_source_pipe);
+error:
+       return NULL;
 }
 
 /*
@@ -3438,6 +3474,61 @@ int ust_app_version(struct ust_app *app)
        return ret;
 }
 
+/*
+ * Setup the base event notifier group.
+ *
+ * Return 0 on success else a negative value either an errno code or a
+ * LTTng-UST error code.
+ */
+int ust_app_setup_event_notifier_group(struct ust_app *app)
+{
+       int ret;
+       int event_pipe_write_fd;
+       struct lttng_ust_object_data *event_notifier_group = NULL;
+       enum lttng_error_code lttng_ret;
+
+       assert(app);
+
+       /* Get the write side of the pipe. */
+       event_pipe_write_fd = lttng_pipe_get_writefd(
+                       app->event_notifier_group.event_pipe);
+
+       pthread_mutex_lock(&app->sock_lock);
+       ret = ustctl_create_event_notifier_group(app->sock,
+                       event_pipe_write_fd, &event_notifier_group);
+       pthread_mutex_unlock(&app->sock_lock);
+       if (ret < 0) {
+               if (ret != -LTTNG_UST_ERR_EXITING && ret != -EPIPE) {
+                       ERR("Failed to create application event notifier group: ret = %d, app socket fd = %d, event_pipe_write_fd = %d",
+                                       ret, app->sock, event_pipe_write_fd);
+               } else {
+                       DBG("Failed to create application event notifier group (application is dead): app socket fd = %d",
+                                       app->sock);
+               }
+
+               goto error;
+       }
+
+       lttng_ret = notification_thread_command_add_tracer_event_source(
+                       notification_thread_handle,
+                       lttng_pipe_get_readfd(app->event_notifier_group.event_pipe),
+                       LTTNG_DOMAIN_UST);
+       if (lttng_ret != LTTNG_OK) {
+               ERR("Failed to add tracer event source to notification thread");
+               ret = - 1;
+               goto error;
+       }
+
+       /* Assign handle only when the complete setup is valid. */
+       app->event_notifier_group.object = event_notifier_group;
+       return ret;
+
+error:
+       ustctl_release_object(app->sock, app->event_notifier_group.object);
+       free(app->event_notifier_group.object);
+       return ret;
+}
+
 /*
  * Unregister app by removing it from the global traceable app list and freeing
  * the data struct.
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