Return error if D-Bus set/get property method is failed

D-Bus set/get property methods are called from GDBusConnection
APIs invoke_set_property_in_idle_cb() and
invoke_get_property_in_idle_cb() and the error values cannot be
null if the methods are failed.

BUG=rhbz#2169205

5 files changed, 113 insertions, 73 deletions

diff --git a/bus/ibusimpl.c b/bus/ibusimpl.c
index c2ae88df..f2ab2b30 100644
--- a/bus/ibusimpl.c
+++ b/bus/ibusimpl.c
@@ -700,11 +700,14 @@ _ibus_get_address (BusIBusImpl     *ibus,
                    GDBusConnection *connection,
                    GError         **error)
 {
-    if (error) {
-        *error = NULL;
+    GVariant *retval = g_variant_new_string (bus_server_get_address ());
+    if (!retval) {
+        g_set_error (error,
+                     G_DBUS_ERROR,
+                     G_DBUS_ERROR_FAILED,
+                     "Cannot get IBus address");
     }
-
-    return g_variant_new_string (bus_server_get_address ());
+    return retval;
 }
 
 static void
@@ -1213,9 +1216,6 @@ _ibus_get_current_input_context (BusIBusImpl     *ibus,
                                  GError         **error)
 {
     GVariant *retval = NULL;
-    if (error) {
-        *error = NULL;
-    }
 
     if (!ibus->focused_context)
     {
@@ -1359,14 +1359,11 @@ _ibus_get_engines (BusIBusImpl     *ibus,
                    GDBusConnection *connection,
                    GError         **error)
 {
+    GVariant *retval;
     GVariantBuilder builder;
     GList *engines = NULL;
     GList *p;
 
-    if (error) {
-        *error = NULL;
-    }
-
     g_variant_builder_init (&builder, G_VARIANT_TYPE ("av"));
 
     engines = g_hash_table_get_values (ibus->engine_table);
@@ -1379,7 +1376,9 @@ _ibus_get_engines (BusIBusImpl     *ibus,
 
     g_list_free (engines);
 
-    return g_variant_builder_end (&builder);
+    retval = g_variant_builder_end (&builder);
+    g_assert (retval);
+    return retval;
 }
 
 static void
@@ -1444,13 +1443,10 @@ _ibus_get_active_engines (BusIBusImpl     *ibus,
                           GDBusConnection *connection,
                           GError         **error)
 {
+    GVariant *retval;
     GVariantBuilder builder;
     GList *p;
 
-    if (error) {
-        *error = NULL;
-    }
-
     g_variant_builder_init (&builder, G_VARIANT_TYPE ("av"));
 
     for (p = ibus->register_engine_list; p != NULL; p = p->next) {
@@ -1459,7 +1455,9 @@ _ibus_get_active_engines (BusIBusImpl     *ibus,
                 ibus_serializable_serialize ((IBusSerializable *) p->data));
     }
 
-    return g_variant_builder_end (&builder);
+    retval = g_variant_builder_end (&builder);
+    g_assert (retval);
+    return retval;
 }
 
 static void
@@ -1528,10 +1526,8 @@ _ibus_get_use_sys_layout (BusIBusImpl     *ibus,
                           GDBusConnection *connection,
                           GError         **error)
 {
-    if (error) {
+    if (error)
         *error = NULL;
-    }
-
     return g_variant_new_boolean (ibus->use_sys_layout);
 }
 
@@ -1566,10 +1562,8 @@ _ibus_get_use_global_engine (BusIBusImpl     *ibus,
                              GDBusConnection *connection,
                              GError         **error)
 {
-    if (error) {
+    if (error)
         *error = NULL;
-    }
-
     return g_variant_new_boolean (ibus->use_global_engine);
 }
 
@@ -1607,10 +1601,6 @@ _ibus_get_global_engine (BusIBusImpl     *ibus,
     IBusEngineDesc *desc = NULL;
     GVariant *retval = NULL;
 
-    if (error) {
-        *error = NULL;
-    }
-
     do {
         if (!ibus->use_global_engine)
             break;
@@ -1790,10 +1780,8 @@ _ibus_get_global_engine_enabled (BusIBusImpl     *ibus,
 {
     gboolean enabled = FALSE;
 
-    if (error) {
+    if (error)
         *error = NULL;
-    }
-
     do {
         if (!ibus->use_global_engine)
             break;
@@ -1849,10 +1837,6 @@ _ibus_set_preload_engines (BusIBusImpl     *ibus,
     BusFactoryProxy *factory = NULL;
     GPtrArray *array = g_ptr_array_new ();
 
-    if (error) {
-        *error = NULL;
-    }
-
     g_variant_get (value, "^a&s", &names);
 
     for (i = 0; names[i] != NULL; i++) {
@@ -1912,11 +1896,9 @@ _ibus_get_embed_preedit_text (BusIBusImpl     *ibus,
                               GDBusConnection *connection,
                               GError         **error)
 {
-    if (error) {
-        *error = NULL;
-    }
-
-    return g_variant_new_boolean (ibus->embed_preedit_text);
+    GVariant *retval = g_variant_new_boolean (ibus->embed_preedit_text);
+    g_assert (retval);
+    return retval;
 }
 
 /**
@@ -1931,10 +1913,6 @@ _ibus_set_embed_preedit_text (BusIBusImpl     *ibus,
                               GVariant        *value,
                               GError         **error)
 {
-    if (error) {
-        *error = NULL;
-    }
-
     gboolean embed_preedit_text = g_variant_get_boolean (value);
     if (embed_preedit_text != ibus->embed_preedit_text) {
         ibus->embed_preedit_text = embed_preedit_text;
@@ -2038,6 +2016,8 @@ bus_ibus_impl_service_get_property (IBusService     *service,
         { "EmbedPreeditText",      _ibus_get_embed_preedit_text },
     };
 
+    if (error)
+        *error = NULL;
     if (g_strcmp0 (interface_name, IBUS_INTERFACE_IBUS) != 0) {
         return IBUS_SERVICE_CLASS (
                 bus_ibus_impl_parent_class)->service_get_property (
@@ -2054,9 +2034,12 @@ bus_ibus_impl_service_get_property (IBusService     *service,
         }
     }
 
-    g_warning ("service_get_property received an unknown property: %s",
-               property_name ? property_name : "(null)");
-    return NULL;
+    g_set_error (error,
+                 G_DBUS_ERROR,
+                 G_DBUS_ERROR_FAILED,
+                 "service_get_property received an unknown property: %s",
+                 property_name ? property_name : "(null)");
+    g_return_val_if_reached (NULL);
 }
 
 /**
@@ -2087,6 +2070,8 @@ bus_ibus_impl_service_set_property (IBusService     *service,
         { "EmbedPreeditText",      _ibus_set_embed_preedit_text },
     };
 
+    if (error)
+        *error = NULL;
     if (g_strcmp0 (interface_name, IBUS_INTERFACE_IBUS) != 0) {
         return IBUS_SERVICE_CLASS (
                 bus_ibus_impl_parent_class)->service_set_property (
@@ -2104,9 +2089,12 @@ bus_ibus_impl_service_set_property (IBusService     *service,
         }
     }
 
-    g_warning ("service_set_property received an unknown property: %s",
-               property_name ? property_name : "(null)");
-    return FALSE;
+    g_set_error (error,
+                 G_DBUS_ERROR,
+                 G_DBUS_ERROR_FAILED,
+                 "service_set_property received an unknown property: %s",
+                 property_name ? property_name : "(null)");
+    g_return_val_if_reached (FALSE);
 }
 
 BusIBusImpl *
diff --git a/bus/inputcontext.c b/bus/inputcontext.c
index 72041ecb..e76bbdfc 100644
--- a/bus/inputcontext.c
+++ b/bus/inputcontext.c
@@ -2,7 +2,7 @@
 /* vim:set et sts=4: */
 /* ibus - The Input Bus
  * Copyright (C) 2008-2014 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2015-2018 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2015-2023 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Copyright (C) 2008-2016 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
@@ -1388,6 +1388,8 @@ bus_input_context_service_set_property (IBusService     *service,
                                         GVariant        *value,
                                         GError         **error)
 {
+    if (error)
+        *error = NULL;
     if (g_strcmp0 (interface_name, IBUS_INTERFACE_INPUT_CONTEXT) != 0) {
         return IBUS_SERVICE_CLASS (bus_input_context_parent_class)->
             service_set_property (service,
@@ -1400,10 +1402,22 @@ bus_input_context_service_set_property (IBusService     *service,
                                   error);
     }
 
-    if (!bus_input_context_service_authorized_method (service, connection))
+    if (!BUS_IS_INPUT_CONTEXT (service)) {
+        g_set_error (error,
+                     G_DBUS_ERROR,
+                     G_DBUS_ERROR_FAILED,
+                     "%p is not BusInputContext.", service);
         return FALSE;
-
-    g_return_val_if_fail (BUS_IS_INPUT_CONTEXT (service), FALSE);
+    }
+    if (!bus_input_context_service_authorized_method (service, connection)) {
+        /* No error message due to the security issue but GError is required
+         * by gdbusconnection.c:invoke_set_property_in_idle_cb() */
+        g_set_error (error,
+                     G_DBUS_ERROR,
+                     G_DBUS_ERROR_FAILED,
+                     " ");
+        return FALSE;
+    }
 
     if (g_strcmp0 (property_name, "ContentType") == 0) {
         _ic_set_content_type (BUS_INPUT_CONTEXT (service), value);
@@ -1414,6 +1428,11 @@ bus_input_context_service_set_property (IBusService     *service,
         return TRUE;
     }
 
+    g_set_error (error,
+                 G_DBUS_ERROR,
+                 G_DBUS_ERROR_FAILED,
+                 "service_set_property received an unknown property: %s",
+                 property_name ? property_name : "(null)");
     g_return_val_if_reached (FALSE);
 }
 
diff --git a/src/ibusengine.c b/src/ibusengine.c
index 8aa27b66..321a58a1 100644
--- a/src/ibusengine.c
+++ b/src/ibusengine.c
@@ -1512,11 +1512,10 @@ _ibus_engine_get_active_surrounding_text (IBusEngine      *engine,
                                           GDBusConnection *connection,
                                           GError         **error)
 {
-    if (error) {
-        *error = NULL;
-    }
-
-    return g_variant_new_boolean (engine->priv->has_active_surrounding_text);
+    GVariant *retval = g_variant_new_boolean (
+            engine->priv->has_active_surrounding_text);
+    g_assert (retval);
+    return retval;
 }
 
 /**
@@ -1529,11 +1528,9 @@ _ibus_engine_has_focus_id (IBusEngine      *engine,
                            GDBusConnection *connection,
                            GError         **error)
 {
-    if (error) {
-        *error = NULL;
-    }
-
-    return g_variant_new_boolean (engine->priv->has_focus_id);
+    GVariant *retval = g_variant_new_boolean (engine->priv->has_focus_id);
+    g_assert (retval);
+    return retval;
 }
 
 static GVariant *
@@ -1556,6 +1553,8 @@ ibus_engine_service_get_property (IBusService        *service,
         { "ActiveSurroundingText",  _ibus_engine_get_active_surrounding_text },
     };
 
+    if (error)
+        *error = NULL;
     if (g_strcmp0 (interface_name, IBUS_INTERFACE_ENGINE) != 0) {
         return IBUS_SERVICE_CLASS (ibus_engine_parent_class)->
                 service_get_property (service,
@@ -1575,9 +1574,12 @@ ibus_engine_service_get_property (IBusService        *service,
         }
     }
 
-    g_warning ("service_get_property received an unknown property: %s",
-               property_name ? property_name : "(null)");
-    return NULL;
+    g_set_error (error,
+                 G_DBUS_ERROR,
+                 G_DBUS_ERROR_FAILED,
+                 "service_get_property received an unknown property: %s",
+                 property_name ? property_name : "(null)");
+    g_return_val_if_reached (NULL);
 }
 
 static gboolean
@@ -1592,6 +1594,8 @@ ibus_engine_service_set_property (IBusService        *service,
 {
     IBusEngine *engine = IBUS_ENGINE (service);
 
+    if (error)
+        *error = NULL;
     if (g_strcmp0 (interface_name, IBUS_INTERFACE_ENGINE) != 0) {
         return IBUS_SERVICE_CLASS (ibus_engine_parent_class)->
             service_set_property (service,
@@ -1604,8 +1608,15 @@ ibus_engine_service_set_property (IBusService        *service,
                                   error);
     }
 
-    if (!ibus_engine_service_authorized_method (service, connection))
+    if (!ibus_engine_service_authorized_method (service, connection)) {
+        /* No error message due to the security issue but GError is required
+         * by gdbusconnection.c:invoke_set_property_in_idle_cb() */
+        g_set_error (error,
+                     G_DBUS_ERROR,
+                     G_DBUS_ERROR_FAILED,
+                     " ");
         return FALSE;
+    }
 
     if (g_strcmp0 (property_name, "ContentType") == 0) {
         guint purpose = 0;
@@ -1629,6 +1640,11 @@ ibus_engine_service_set_property (IBusService        *service,
         return TRUE;
     }
 
+    g_set_error (error,
+                 G_DBUS_ERROR,
+                 G_DBUS_ERROR_FAILED,
+                 "service_set_property received an unknown property: %s",
+                 property_name ? property_name : "(null)");
     g_return_val_if_reached (FALSE);
 }
 
diff --git a/src/ibusenginesimple.c b/src/ibusenginesimple.c
index 3d1668b2..409d5a56 100644
--- a/src/ibusenginesimple.c
+++ b/src/ibusenginesimple.c
@@ -158,7 +158,7 @@ ibus_engine_simple_init (IBusEngineSimple *simple)
                                     G_RESOURCE_LOOKUP_FLAGS_NONE,
                                     &error);
     if (error) {
-        g_warning ("Nout found compose resource %s", error->message);
+        g_warning ("Not found compose resource %s", error->message);
         g_clear_error (&error);
         return;
     }
diff --git a/src/ibusservice.c b/src/ibusservice.c
index 60255bd5..d207f707 100644
--- a/src/ibusservice.c
+++ b/src/ibusservice.c
@@ -2,7 +2,7 @@
 /* vim:set et sts=4: */
 /* ibus - The Input Bus
  * Copyright (C) 2008-2015 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2015-2019 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2015-2023 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Copyright (C) 2008-2019 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
@@ -370,8 +370,9 @@ ibus_service_service_method_call (IBusService           *service,
     g_dbus_method_invocation_return_error (invocation,
                                            G_DBUS_ERROR,
                                            G_DBUS_ERROR_UNKNOWN_METHOD,
-                                           "%s::%s", interface_name, method_name);
-    return;
+                                           "%s::%s",
+                                           interface_name, method_name);
+    g_return_if_reached ();
 }
 
 static GVariant *
@@ -383,7 +384,15 @@ ibus_service_service_get_property (IBusService     *service,
                                   const gchar      *property_name,
                                   GError          **error)
 {
-    return NULL;
+    if (error) {
+        *error = NULL;
+        g_set_error (error,
+                     G_DBUS_ERROR,
+                     G_DBUS_ERROR_FAILED,
+                     "service_get_property received an unknown property: %s",
+                     property_name ? property_name : "(null)");
+    }
+    g_return_val_if_reached (NULL);
 }
 
 static gboolean
@@ -396,7 +405,15 @@ ibus_service_service_set_property (IBusService     *service,
                                   GVariant         *value,
                                   GError          **error)
 {
-    return FALSE;
+    if (error) {
+        *error = NULL;
+        g_set_error (error,
+                     G_DBUS_ERROR,
+                     G_DBUS_ERROR_FAILED,
+                     "service_set_property received an unknown property: %s",
+                     property_name ? property_name : "(null)");
+    }
+    g_return_val_if_reached (FALSE);
 }
 
 static void