media-keys: fix race condition

For some reason I see a crash in the settings daemon in the
gsettings_changed_cb() callback when accessing manager->priv->keys->len.

It seems that the gsettings callback is called before
manager->priv->keys is initialized. And that would happen after
because init_kbd() which initialized manager->priv->keys is called
upon shell's dbus appearance.

https://bugzilla.gnome.org/show_bug.cgi?id=697698

1 files changed, 9 insertions, 2 deletions

diff --git a/plugins/media-keys/gsd-media-keys-manager.c b/plugins/media-keys/gsd-media-keys-manager.c
index 6c788971..0fc776f2 100644
--- a/plugins/media-keys/gsd-media-keys-manager.c
+++ b/plugins/media-keys/gsd-media-keys-manager.c
@@ -596,6 +596,10 @@ gsettings_changed_cb (GSettings           *settings,
 {
         int      i;
 
+        /* Give up if we don't have proxy to the shell */
+        if (!manager->priv->key_grabber)
+                return;
+
 	/* handled in gsettings_custom_changed_cb() */
         if (g_str_equal (settings_key, "custom-keybindings"))
 		return;
@@ -765,8 +769,6 @@ init_kbd (GsdMediaKeysManager *manager)
 
         gnome_settings_profile_start (NULL);
 
-        manager->priv->keys = g_ptr_array_new_with_free_func ((GDestroyNotify) media_key_free);
-
         /* Media keys
          * Add hard-coded shortcuts first so that they can't be preempted */
         for (i = 0; i < G_N_ELEMENTS (media_keys); i++) {
@@ -2252,6 +2254,9 @@ on_shell_vanished (GDBusConnection  *connection,
                    gpointer          user_data)
 {
         GsdMediaKeysManager *manager = user_data;
+
+        g_ptr_array_set_size (manager->priv->keys, 0);
+
         g_clear_object (&manager->priv->key_grabber);
         g_clear_object (&manager->priv->osd_proxy);
 }
@@ -2264,6 +2269,8 @@ start_media_keys_idle_cb (GsdMediaKeysManager *manager)
         g_debug ("Starting media_keys manager");
         gnome_settings_profile_start (NULL);
 
+        manager->priv->keys = g_ptr_array_new_with_free_func ((GDestroyNotify) media_key_free);
+
         initialize_volume_handler (manager);
 
         manager->priv->settings = g_settings_new (SETTINGS_BINDING_DIR);