session-quit: Use a unique dialog server address for each session.

This was preventing the logout dialog for subsequent users logged
in, as it would attempt to connect to the original user's server
(and be denied).

A unique address will be generated at startup, and passed to
the dialog when it is launched.

Fixes linuxmint/cinnamon#12021

Author: mtwebster

cinnamon-session-quit/cinnamon-session-quit.py

@@ -64,6 +64,7 @@ def __init__(self):
         parser.add_argument("--no-prompt", dest="no_prompt", action='store_true',
                             help=_("Don't prompt for user confirmation"))
         parser.add_argument("--sm-owned", action="store_true", help=argparse.SUPPRESS)
+        parser.add_argument("--sm-bus-id", dest="bus_id", action="store", help=argparse.SUPPRESS)
         args = parser.parse_args()
 
         self.dialog_response = ResponseCode.NONE
@@ -76,6 +77,11 @@ def __init__(self):
         self.no_prompt = args.no_prompt
         self.sm_owned = args.sm_owned
 
+        if self.sm_owned:
+            self.bus_id = args.bus_id
+        else:
+            self.bus_id = None
+
         self.proxy = None
         self.signal_handler_id = 0
 
@@ -164,7 +170,7 @@ def setup_proxy(self):
 
         try:
             connection = Gio.DBusConnection.new_for_address_sync(
-                config.DBUS_ADDRESS,
+                self.bus_id,
                 Gio.DBusConnectionFlags.AUTHENTICATION_CLIENT,
                 None, None
             )

cinnamon-session/csm-manager.c

@@ -125,6 +125,7 @@ struct CsmManagerPrivate
         GDBusServer            *dialog_server;
         guint                   dialog_reg_id;
         CsmLogoutAction         dialog_action;
+        gchar                  *dialog_bus_address;
 
         char                   *session_name;
         gboolean                is_fallback_session : 1;
@@ -2917,7 +2918,10 @@ register_manager (CsmManager *manager)
 
         // Set up private controller interface for dialog
         gchar *guid = g_dbus_generate_guid ();
-        GDBusServer *server = g_dbus_server_new_sync (DBUS_ADDRESS,
+        manager->priv->dialog_bus_address = g_strdup_printf ("%s-%s", DBUS_ADDRESS, guid);
+        g_debug ("Dialog server address: %s", manager->priv->dialog_bus_address);
+
+        GDBusServer *server = g_dbus_server_new_sync (manager->priv->dialog_bus_address,
                                                       G_DBUS_SERVER_FLAGS_AUTHENTICATION_REQUIRE_SAME_USER,
                                                       guid,
                                                       NULL, NULL, &error);
@@ -3537,6 +3541,9 @@ csm_manager_dispose (GObject *object)
                 manager->priv->dialog_reg_id = 0;
                 g_dbus_node_info_unref (introspection_data);
                 g_dbus_server_stop (manager->priv->dialog_server);
+                g_object_unref (manager->priv->dialog_server);
+                g_object_unref (manager->priv->dialog_connection);
+                g_free (manager->priv->dialog_bus_address);
         }
 
         if (manager->priv->clients != NULL) {
@@ -3926,6 +3933,34 @@ on_dialog_exited (GObject *source,
     g_clear_object (&dialog_cancellable);
 }
 
+static void
+on_dialog_read (GObject *source,
+                GAsyncResult *result,
+                gpointer user_data)
+{
+    GInputStream *stream = G_INPUT_STREAM (source);
+
+    g_debug ("Session quit dialog read output");
+
+    gssize read = g_input_stream_read_finish (stream, result, NULL);
+    if (read > 0) {
+        g_debug ("Session quit dialog (self-owned) output: %.*s", (gint) read, (gchar *) user_data);
+    } else {
+        g_debug ("Session quit dialog (self-owned) stdout closed");
+        g_free (user_data);
+        g_input_stream_close (stream, NULL, NULL);
+        return;
+    }
+
+    g_input_stream_read_async (stream,
+                               user_data,
+                               1024,
+                               G_PRIORITY_DEFAULT,
+                               NULL,
+                               (GAsyncReadyCallback) on_dialog_read,
+                               user_data);
+}
+
 static void
 terminate_dialog (void)
 {
@@ -3959,12 +3994,13 @@ launch_dialog (CsmManager *manager, const gchar *flag)
     const gchar *argv[] = {
         "cinnamon-session-quit",
         "--sm-owned",
+        "--sm-bus-id", manager->priv->dialog_bus_address,
         flag,
         NULL
     };
 
     error = NULL;
-    dialog_process = g_subprocess_newv (argv, G_SUBPROCESS_FLAGS_NONE, &error);
+    dialog_process = g_subprocess_newv (argv, G_SUBPROCESS_FLAGS_STDERR_MERGE | G_SUBPROCESS_FLAGS_STDOUT_PIPE, &error);
 
     if (dialog_process == NULL) {
         if (error != NULL) {
@@ -3974,6 +4010,16 @@ launch_dialog (CsmManager *manager, const gchar *flag)
         }
     }
 
+    GInputStream *stdout = g_subprocess_get_stdout_pipe (dialog_process);
+    guint8 *buffer = g_malloc (1024);
+    g_input_stream_read_async (G_INPUT_STREAM (stdout),
+                               buffer,
+                               1024,
+                               G_PRIORITY_DEFAULT,
+                               NULL,
+                               (GAsyncReadyCallback) on_dialog_read,
+                               buffer);
+
     dialog_cancellable = g_cancellable_new ();
 
     g_subprocess_wait_async (dialog_process,