D-Bus: Use a helper function to get possibly NULL strings

This type of check is used in quite a few getter functions, so add a
helper function to take care of it.

Signed-off-by: Jouni Malinen <j@w1.fi>

wpa_supplicant/dbus/dbus_new_handlers.c

@@ -516,6 +516,27 @@ dbus_bool_t wpas_dbus_simple_array_array_property_getter(DBusMessageIter *iter,
 }
 
 
+/**
+ * wpas_dbus_string_property_getter - Get string type property
+ * @iter: Message iter to use when appending arguments
+ * @val: Pointer to place holding property value, can be %NULL
+ * @error: On failure an error describing the failure
+ * Returns: TRUE if the request was successful, FALSE if it failed
+ *
+ * Generic getter for string type properties. %NULL is converted to an empty
+ * string.
+ */
+dbus_bool_t wpas_dbus_string_property_getter(DBusMessageIter *iter,
+					     const void *val,
+					     DBusError *error)
+{
+	if (!val)
+		val = "";
+	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
+						&val, error);
+}
+
+
 /**
  * wpas_dbus_handler_create_interface - Request registration of a network iface
  * @message: Pointer to incoming dbus message
@@ -3086,10 +3107,8 @@ dbus_bool_t wpas_dbus_getter_ifname(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	const char *ifname = wpa_s->ifname;
 
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&ifname, error);
+	return wpas_dbus_string_property_getter(iter, wpa_s->ifname, error);
 }
 
 
@@ -3107,7 +3126,6 @@ dbus_bool_t wpas_dbus_getter_driver(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	const char *driver;
 
 	if (wpa_s->driver == NULL || wpa_s->driver->name == NULL) {
 		wpa_printf(MSG_DEBUG, "%s[dbus]: wpa_s has no driver set",
@@ -3117,9 +3135,8 @@ dbus_bool_t wpas_dbus_getter_driver(
 		return FALSE;
 	}
 
-	driver = wpa_s->driver->name;
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&driver, error);
+	return wpas_dbus_string_property_getter(iter, wpa_s->driver->name,
+						error);
 }
 
 
@@ -3232,10 +3249,9 @@ dbus_bool_t wpas_dbus_getter_bridge_ifname(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	const char *bridge_ifname = wpa_s->bridge_ifname;
 
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&bridge_ifname, error);
+	return wpas_dbus_string_property_getter(iter, wpa_s->bridge_ifname,
+						error);
 }
 
 
@@ -3253,13 +3269,8 @@ dbus_bool_t wpas_dbus_getter_config_file(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	char *confname = "";
-
-	if (wpa_s->confname)
-		confname = wpa_s->confname;
 
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&confname, error);
+	return wpas_dbus_string_property_getter(iter, wpa_s->confname, error);
 }
 
 
@@ -3399,14 +3410,10 @@ dbus_bool_t wpas_dbus_getter_pkcs11_engine_path(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	const char *pkcs11_engine_path;
 
-	if (wpa_s->conf->pkcs11_engine_path == NULL)
-		pkcs11_engine_path = "";
-	else
-		pkcs11_engine_path = wpa_s->conf->pkcs11_engine_path;
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&pkcs11_engine_path, error);
+	return wpas_dbus_string_property_getter(iter,
+						wpa_s->conf->pkcs11_engine_path,
+						error);
 }
 
 
@@ -3424,14 +3431,10 @@ dbus_bool_t wpas_dbus_getter_pkcs11_module_path(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	const char *pkcs11_module_path;
 
-	if (wpa_s->conf->pkcs11_module_path == NULL)
-		pkcs11_module_path = "";
-	else
-		pkcs11_module_path = wpa_s->conf->pkcs11_module_path;
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&pkcs11_module_path, error);
+	return wpas_dbus_string_property_getter(iter,
+						wpa_s->conf->pkcs11_module_path,
+						error);
 }
 
 

wpa_supplicant/dbus/dbus_new_handlers.h

@@ -43,6 +43,10 @@ dbus_bool_t wpas_dbus_simple_array_array_property_getter(DBusMessageIter *iter,
 							 size_t array_len,
 							 DBusError *error);
 
+dbus_bool_t wpas_dbus_string_property_getter(DBusMessageIter *iter,
+					     const void *val,
+					     DBusError *error);
+
 DBusMessage * wpas_dbus_handler_create_interface(DBusMessage *message,
 						 struct wpa_global *global);
 

wpa_supplicant/dbus/dbus_new_handlers_p2p.c

@@ -2352,19 +2352,12 @@ dbus_bool_t wpas_dbus_getter_p2p_group_passphrase(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	char *p_pass;
 	struct wpa_ssid *ssid = wpa_s->current_ssid;
 
 	if (ssid == NULL)
 		return FALSE;
 
-	p_pass = ssid->passphrase;
-	if (!p_pass)
-		p_pass = "";
-
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&p_pass, error);
-
+	return wpas_dbus_string_property_getter(iter, ssid->passphrase, error);
 }
 
 

wpa_supplicant/dbus/dbus_new_handlers_wps.c

@@ -412,12 +412,10 @@ dbus_bool_t wpas_dbus_getter_config_methods(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	char *methods = wpa_s->conf->config_methods;
 
-	if (methods == NULL)
-		methods = "";
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&methods, error);
+	return wpas_dbus_string_property_getter(iter,
+						wpa_s->conf->config_methods,
+						error);
 }
 
 
@@ -470,12 +468,9 @@ dbus_bool_t wpas_dbus_getter_wps_device_name(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	char *methods = wpa_s->conf->device_name;
 
-	if (!methods)
-		methods = "";
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&methods, error);
+	return wpas_dbus_string_property_getter(iter, wpa_s->conf->device_name,
+						error);
 }
 
 
@@ -529,12 +524,9 @@ dbus_bool_t wpas_dbus_getter_wps_manufacturer(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	char *manufacturer = wpa_s->conf->manufacturer;
 
-	if (!manufacturer)
-		manufacturer = "";
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&manufacturer, error);
+	return wpas_dbus_string_property_getter(iter, wpa_s->conf->manufacturer,
+						error);
 }
 
 
@@ -588,12 +580,9 @@ dbus_bool_t wpas_dbus_getter_wps_device_model_name(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	char *model_name = wpa_s->conf->model_name;
 
-	if (!model_name)
-		model_name = "";
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&model_name, error);
+	return wpas_dbus_string_property_getter(iter, wpa_s->conf->model_name,
+						error);
 }
 
 
@@ -646,12 +635,9 @@ dbus_bool_t wpas_dbus_getter_wps_device_model_number(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	char *model_number = wpa_s->conf->model_number;
 
-	if (!model_number)
-		model_number = "";
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&model_number, error);
+	return wpas_dbus_string_property_getter(iter, wpa_s->conf->model_number,
+						error);
 }
 
 
@@ -705,12 +691,10 @@ dbus_bool_t wpas_dbus_getter_wps_device_serial_number(
 	DBusMessageIter *iter, DBusError *error, void *user_data)
 {
 	struct wpa_supplicant *wpa_s = user_data;
-	char *model_number = wpa_s->conf->serial_number;
 
-	if (!model_number)
-		model_number = "";
-	return wpas_dbus_simple_property_getter(iter, DBUS_TYPE_STRING,
-						&model_number, error);
+	return wpas_dbus_string_property_getter(iter,
+						wpa_s->conf->serial_number,
+						error);
 }