dbus: Raise PropertiesChanged on org.freedesktop.DBus.Properties

wpa_supplicant dbus objects are currently difficult to use with
GDBusProxy. This is because they do not follow the dbus standard in
emitting the PropertiesChanged signal on the standard D-Bus properties
interface, so GDBusProxy stores stale property values.

Fix this by raising PropertiesChanged on the standard interface.
For backwards compatibility, the existing custom PropertiesChanged
signals are not removed; I anticipate them being removed in a future
major release.

See
http://lists.freedesktop.org/archives/dbus/2011-August/014593.html
for more info.

Signed-off-by: Daniel Drake <dsd@laptop.org>

wpa_supplicant/dbus/dbus_new.c

@@ -1689,6 +1689,7 @@ static const struct wpa_dbus_signal_desc wpas_dbus_global_signals[] = {
 		  END_ARGS
 	  }
 	},
+	/* Deprecated: use org.freedesktop.DBus.Properties.PropertiesChanged */
 	{ "PropertiesChanged", WPAS_DBUS_NEW_INTERFACE,
 	  {
 		  { "properties", "a{sv}", ARG_OUT },
@@ -1777,6 +1778,7 @@ static const struct wpa_dbus_property_desc wpas_dbus_network_properties[] = {
 
 
 static const struct wpa_dbus_signal_desc wpas_dbus_network_signals[] = {
+	/* Deprecated: use org.freedesktop.DBus.Properties.PropertiesChanged */
 	{ "PropertiesChanged", WPAS_DBUS_NEW_IFACE_NETWORK,
 	  {
 		  { "properties", "a{sv}", ARG_OUT },
@@ -1953,6 +1955,7 @@ static const struct wpa_dbus_property_desc wpas_dbus_bss_properties[] = {
 
 
 static const struct wpa_dbus_signal_desc wpas_dbus_bss_signals[] = {
+	/* Deprecated: use org.freedesktop.DBus.Properties.PropertiesChanged */
 	{ "PropertiesChanged", WPAS_DBUS_NEW_IFACE_BSS,
 	  {
 		  { "properties", "a{sv}", ARG_OUT },
@@ -2477,6 +2480,7 @@ static const struct wpa_dbus_signal_desc wpas_dbus_interface_signals[] = {
 		  END_ARGS
 	  }
 	},
+	/* Deprecated: use org.freedesktop.DBus.Properties.PropertiesChanged */
 	{ "PropertiesChanged", WPAS_DBUS_NEW_IFACE_INTERFACE,
 	  {
 		  { "properties", "a{sv}", ARG_OUT },
@@ -2497,6 +2501,7 @@ static const struct wpa_dbus_signal_desc wpas_dbus_interface_signals[] = {
 		  END_ARGS
 	  }
 	},
+	/* Deprecated: use org.freedesktop.DBus.Properties.PropertiesChanged */
 	{ "PropertiesChanged", WPAS_DBUS_NEW_IFACE_WPS,
 	  {
 		  { "properties", "a{sv}", ARG_OUT },

wpa_supplicant/dbus/dbus_new_helpers.c

@@ -610,7 +610,7 @@ int wpa_dbus_unregister_object_per_iface(
 
 static dbus_bool_t put_changed_properties(
 	const struct wpa_dbus_object_desc *obj_dsc, const char *interface,
-	DBusMessageIter *dict_iter)
+	DBusMessageIter *dict_iter, int clear_changed)
 {
 	DBusMessageIter entry_iter;
 	const struct wpa_dbus_property_desc *dsc;
@@ -624,7 +624,8 @@ static dbus_bool_t put_changed_properties(
 			continue;
 		if (os_strcmp(dsc->dbus_interface, interface) != 0)
 			continue;
-		obj_dsc->prop_changed_flags[i] = 0;
+		if (clear_changed)
+			obj_dsc->prop_changed_flags[i] = 0;
 
 		if (!dbus_message_iter_open_container(dict_iter,
 						      DBUS_TYPE_DICT_ENTRY,
@@ -660,7 +661,57 @@ static dbus_bool_t put_changed_properties(
 }
 
 
-static void send_prop_changed_signal(
+static void do_send_prop_changed_signal(
+	DBusConnection *con, const char *path, const char *interface,
+	const struct wpa_dbus_object_desc *obj_dsc)
+{
+	DBusMessage *msg;
+	DBusMessageIter signal_iter, dict_iter;
+
+	msg = dbus_message_new_signal(path, DBUS_INTERFACE_PROPERTIES,
+				      "PropertiesChanged");
+	if (msg == NULL)
+		return;
+
+	dbus_message_iter_init_append(msg, &signal_iter);
+
+	if (!dbus_message_iter_append_basic(&signal_iter, DBUS_TYPE_STRING,
+					    &interface))
+		goto err;
+
+	/* Changed properties dict */
+	if (!dbus_message_iter_open_container(&signal_iter, DBUS_TYPE_ARRAY,
+					      "{sv}", &dict_iter))
+		goto err;
+
+	if (!put_changed_properties(obj_dsc, interface, &dict_iter, 0))
+		goto err;
+
+	if (!dbus_message_iter_close_container(&signal_iter, &dict_iter))
+		goto err;
+
+	/* Invalidated properties array (empty) */
+	if (!dbus_message_iter_open_container(&signal_iter, DBUS_TYPE_ARRAY,
+					      "s", &dict_iter))
+		goto err;
+
+	if (!dbus_message_iter_close_container(&signal_iter, &dict_iter))
+		goto err;
+
+	dbus_connection_send(con, msg, NULL);
+
+out:
+	dbus_message_unref(msg);
+	return;
+
+err:
+	wpa_printf(MSG_DEBUG, "dbus: %s: Failed to construct signal",
+		   __func__);
+	goto out;
+}
+
+
+static void do_send_deprecated_prop_changed_signal(
 	DBusConnection *con, const char *path, const char *interface,
 	const struct wpa_dbus_object_desc *obj_dsc)
 {
@@ -677,7 +728,7 @@ static void send_prop_changed_signal(
 					      "{sv}", &dict_iter))
 		goto err;
 
-	if (!put_changed_properties(obj_dsc, interface, &dict_iter))
+	if (!put_changed_properties(obj_dsc, interface, &dict_iter, 1))
 		goto err;
 
 	if (!dbus_message_iter_close_container(&signal_iter, &dict_iter))
@@ -696,6 +747,29 @@ err:
 }
 
 
+static void send_prop_changed_signal(
+	DBusConnection *con, const char *path, const char *interface,
+	const struct wpa_dbus_object_desc *obj_dsc)
+{
+	/*
+	 * First, send property change notification on the standardized
+	 * org.freedesktop.DBus.Properties interface. This call will not
+	 * clear the property change bits, so that they are preserved for
+	 * the call that follows.
+	 */
+	do_send_prop_changed_signal(con, path, interface, obj_dsc);
+
+	/*
+	 * Now send PropertiesChanged on our own interface for backwards
+	 * compatibility. This is deprecated and will be removed in a future
+	 * release.
+	 */
+	do_send_deprecated_prop_changed_signal(con, path, interface, obj_dsc);
+
+	/* Property change bits have now been cleared. */
+}
+
+
 static void flush_object_timeout_handler(void *eloop_ctx, void *timeout_ctx)
 {
 	DBusConnection *con = eloop_ctx;