Unregister all shutdown consumers when receiving SIGTERM

systemd uses SIGTERM to stop its units. We want to cleanly shut down
the NSC when receiving this signal. Part of that is to unregister all
shutdown consumers. If we don't do this, the NSM will later during its
shutdown phase call all shutdown consumers registered by the NSC. And
if the NSC was no longer running, this would cause the NSM to wait for a
timeout for every single one of these shutdown consumers. Obviously,
that is not desirable.

diff --git a/node-startup-controller/node-startup-controller-application.c b/node-startup-controller/node-startup-controller-application.c
index b2edc1b..e3684fa 100644 (file)
--- a/node-startup-controller/node-startup-controller-application.c
+++ b/node-startup-controller/node-startup-controller-application.c
@@ -52,29 +52,31 @@ enum
 
 
 
-static void node_startup_controller_application_finalize                     (GObject                          *object);
-static void node_startup_controller_application_constructed                  (GObject                          *object);
-static void node_startup_controller_application_get_property                 (GObject                          *object,
-                                                                              guint                             prop_id,
-                                                                              GValue                           *value,
-                                                                              GParamSpec                       *pspec);
-static gboolean node_startup_controller_application_handle_lifecycle_request (ShutdownConsumer                 *interface,
-                                                                              GDBusMethodInvocation            *invocation,
-                                                                              NSMShutdownType                   request,
-                                                                              guint                             request_id,
-                                                                              NodeStartupControllerApplication *application);
-static void node_startup_controller_application_handle_register_finish       (GObject                          *object,
-                                                                              GAsyncResult                     *res,
-                                                                              gpointer                          user_data);
-static void node_startup_controller_application_handle_unregister_finish     (GObject                          *object,
-                                                                              GAsyncResult                     *res,
-                                                                              gpointer                          user_data);
-static void node_startup_controller_application_set_property                 (GObject                          *object,
-                                                                              guint                             prop_id,
-                                                                              const GValue                     *value,
-                                                                              GParamSpec                       *pspec);
-static void node_startup_controller_application_luc_groups_started           (LUCStarter                       *starter,
-                                                                              NodeStartupControllerApplication *application);
+static void     node_startup_controller_application_finalize                     (GObject                          *object);
+static void     node_startup_controller_application_constructed                  (GObject                          *object);
+static void     node_startup_controller_application_get_property                 (GObject                          *object,
+                                                                                  guint                             prop_id,
+                                                                                  GValue                           *value,
+                                                                                  GParamSpec                       *pspec);
+static gboolean node_startup_controller_application_handle_lifecycle_request     (ShutdownConsumer                 *interface,
+                                                                                  GDBusMethodInvocation            *invocation,
+                                                                                  NSMShutdownType                   request,
+                                                                                  guint                             request_id,
+                                                                                  NodeStartupControllerApplication *application);
+static void     node_startup_controller_application_handle_register_finish       (GObject                          *object,
+                                                                                  GAsyncResult                     *res,
+                                                                                  gpointer                          user_data);
+static void     node_startup_controller_application_handle_unregister_finish     (GObject                          *object,
+                                                                                  GAsyncResult                     *res,
+                                                                                  gpointer                          user_data);
+static void     node_startup_controller_application_set_property                 (GObject                          *object,
+                                                                                  guint                             prop_id,
+                                                                                  const GValue                     *value,
+                                                                                  GParamSpec                       *pspec);
+static void     node_startup_controller_application_luc_groups_started           (LUCStarter                       *starter,
+                                                                                  NodeStartupControllerApplication *application);
+static gboolean node_startup_controller_application_handle_sigterm               (gpointer                          user_data);
+static void     node_startup_controller_application_unregister_shutdown_consumer (NodeStartupControllerApplication *application);
 
 
 
@@ -114,6 +116,9 @@ struct _NodeStartupControllerApplication
 
   /* shutdown client for the node startup controller itself */
   ShutdownClient               *client;
+
+  /* source ID for the SIGTERM handler */
+  guint                         sigterm_id;
 };
 
 
@@ -226,6 +231,12 @@ node_startup_controller_application_init (NodeStartupControllerApplication *appl
                DLT_STRING ("Updating the systemd watchdog timestamp every"),
                DLT_UINT (watchdog_sec), DLT_STRING ("seconds"));
     }
+
+  /* release all registered shutdown consumers upon receiving SIGTERM */
+  application->sigterm_id =
+    g_unix_signal_add (SIGTERM,
+                       node_startup_controller_application_handle_sigterm,
+                       application);
 }
 
 
@@ -270,6 +281,10 @@ node_startup_controller_application_finalize (GObject *object)
   /* release the main loop */
   g_main_loop_unref (application->main_loop);
 
+  /* remove the SIGTERM handler source */
+  if (application->sigterm_id > 0)
+    g_source_remove (application->sigterm_id);
+
   (*G_OBJECT_CLASS (node_startup_controller_application_parent_class)->finalize) (object);
 }
 
@@ -430,11 +445,6 @@ node_startup_controller_application_handle_lifecycle_request (ShutdownConsumer
                                                               guint                             request_id,
                                                               NodeStartupControllerApplication *application)
 {
-  NSMConsumer *nsm_consumer;
-  const gchar *bus_name;
-  const gchar *object_path;
-  gint         shutdown_mode;
-
   g_return_val_if_fail (IS_SHUTDOWN_CONSUMER (consumer), FALSE);
   g_return_val_if_fail (G_IS_DBUS_METHOD_INVOCATION (invocation), FALSE);
   g_return_val_if_fail (IS_NODE_STARTUP_CONTROLLER_APPLICATION (application), FALSE);
@@ -445,19 +455,13 @@ node_startup_controller_application_handle_lifecycle_request (ShutdownConsumer
   /* deregister the shutdown consumers */
   la_handler_service_deregister_consumers (application->la_handler);
 
+  /* deregister the shutdown consumer of the application itself */
+  node_startup_controller_application_unregister_shutdown_consumer (application);
+
   /* let the NSM know that we have handled the lifecycle request */
   shutdown_consumer_complete_lifecycle_request (consumer, invocation,
                                                 NSM_ERROR_STATUS_OK);
 
-  /* deregister the node startup controller as a shutdown client itself */
-  nsm_consumer = la_handler_service_get_nsm_consumer (application->la_handler);
-  bus_name = shutdown_client_get_bus_name (application->client);
-  object_path = shutdown_client_get_object_path (application->client);
-  shutdown_mode = shutdown_client_get_shutdown_mode (application->client);
-  nsm_consumer_call_un_register_shutdown_client (nsm_consumer, bus_name,
-                                                 object_path, shutdown_mode, NULL,
-                                                 node_startup_controller_application_handle_unregister_finish,
-                                                 application);
   return TRUE;
 }
 
@@ -546,6 +550,53 @@ node_startup_controller_application_luc_groups_started (LUCStarter
 
 
 
+static gboolean
+node_startup_controller_application_handle_sigterm (gpointer user_data)
+{
+  NodeStartupControllerApplication *application = NODE_STARTUP_CONTROLLER_APPLICATION (user_data);
+
+  g_return_val_if_fail (IS_NODE_STARTUP_CONTROLLER_APPLICATION (application), FALSE);
+
+  /* deregister the shutdown consumers of legacy applications */
+  la_handler_service_deregister_consumers (application->la_handler);
+
+  /* unregister the shutdown client for the app itself */
+  node_startup_controller_application_unregister_shutdown_consumer (application);
+
+  /* quit the application */
+  g_main_loop_quit (application->main_loop);
+
+  /* reset the source ID */
+  application->sigterm_id = 0;
+
+  return FALSE;
+}
+
+
+
+static void
+node_startup_controller_application_unregister_shutdown_consumer (NodeStartupControllerApplication *application)
+{
+  NSMConsumer *nsm_consumer;
+  const gchar *bus_name;
+  const gchar *object_path;
+  gint         shutdown_mode;
+
+  g_return_if_fail (IS_NODE_STARTUP_CONTROLLER_APPLICATION (application));
+
+  /* deregister the node startup controller as a shutdown client itself */
+  nsm_consumer = la_handler_service_get_nsm_consumer (application->la_handler);
+  bus_name = shutdown_client_get_bus_name (application->client);
+  object_path = shutdown_client_get_object_path (application->client);
+  shutdown_mode = shutdown_client_get_shutdown_mode (application->client);
+  nsm_consumer_call_un_register_shutdown_client (nsm_consumer, bus_name,
+                                                 object_path, shutdown_mode, NULL,
+                                                 node_startup_controller_application_handle_unregister_finish,
+                                                 application);
+}
+
+
+
 NodeStartupControllerApplication *
 node_startup_controller_application_new (GMainLoop                    *main_loop,
                                          GDBusConnection              *connection,