core: create GMainLoop after daemonizing

The GMainLoop instance (and the default GMainContext singleton) is not
required for trivial operations like --print-config, --version or
--help). If running as SysV daemon, the event file descriptor is
unnecessarily dup'ed from the parent to the child process.

Signed-off-by: Christian Eggers <ceggers@arri.de>

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1160

src/core/main.c

@@ -302,8 +302,6 @@ main(int argc, char *argv[])
     g_type_ensure(G_TYPE_DBUS_CONNECTION);
     g_type_ensure(NM_TYPE_DBUS_MANAGER);
 
-    main_loop = g_main_loop_new(NULL, FALSE);
-
     /* we determine a first-start (contrary to a restart during the same boot)
      * based on the existence of NM_CONFIG_DEVICE_STATE_DIR directory. */
     config_cli = nm_config_cmd_line_options_new(
@@ -403,6 +401,8 @@ main(int argc, char *argv[])
         wrote_pidfile = nm_main_utils_write_pidfile(global_opt.pidfile);
     }
 
+    main_loop = g_main_loop_new(NULL, FALSE);
+
     /* Set up unix signal handling - before creating threads, but after daemonizing! */
     nm_main_utils_setup_signals(main_loop);