ifcfg-rh: write the master device name even if the master property is an UUID

We used MASTER, BRIDGE and TEAM_MASTER keys for a differnet purpose than the
network.service did, confusing the legacy tooling. Let's do our best to write
compatible configuration files:

* Add *_UUID properties that won't clash with initscripts
* Ignore non-*_UUID keys on read if *_UUID is present
* If the connection.master is an UUID of a connection with a
  connection.interface-name, write the uuid into the *_UUID key while setting
  the non-*_UUID key to the interface name for compatibility

https://bugzilla.redhat.com/show_bug.cgi?id=1369091

libnm-core/nm-setting-connection.c

@@ -1696,9 +1696,11 @@ nm_setting_connection_class_init (NMSettingConnectionClass *setting_class)
 	 **/
 	/* ---ifcfg-rh---
 	 * property: master
-	 * variable: MASTER, TEAM_MASTER, BRIDGE
+	 * variable: MASTER, MASTER_UUID, TEAM_MASTER, TEAM_MASTER_UUID, BRIDGE, BRIDGE_UUID
 	 * description: Reference to master connection. The variable used depends on
-	 *   the connection type.
+	 *   the connection type and the value. In general, if the *_UUID variant is present,
+	 *   the variant without *_UUID is ignored. NetworkManager attempts to write both
+	 *   for compatibility with legacy tooling.
 	 * ---end---
 	 */
 	g_object_class_install_property
@@ -1719,10 +1721,12 @@ nm_setting_connection_class_init (NMSettingConnectionClass *setting_class)
 	 **/
 	/* ---ifcfg-rh---
 	 * property: slave-type
-	 * variable: MASTER, TEAM_MASTER, DEVICETYPE, BRIDGE
+	 * variable: MASTER, MASTER_UUID, TEAM_MASTER, TEAM_MASTER_UUID, DEVICETYPE,
+	 *   BRIDGE, BRIDGE_UUID
 	 * description: Slave type doesn't map directly to a variable, but it is
-	 *   recognized using different variables.  MASTER for bonding,
+	 *   recognized using different variables.  MASTER and MASTER_UUID for bonding,
-	 *   TEAM_MASTER and DEVICETYPE for teaming, BRIDGE for bridging.
+	 *   TEAM_MASTER, TEAM_MASTER_UUID and DEVICETYPE for teaming, BRIDGE
+	 *   and BRIDGE_UUID for bridging.
 	 * ---end---
 	 */
 	g_object_class_install_property

src/nm-manager.c

@@ -1145,6 +1145,30 @@ nm_manager_get_connection_iface (NMManager *self,
 	return iface;
 }
 
+/**
+ * nm_manager_iface_for_uuid:
+ * @self: the #NMManager
+ * @uuid: the connection uuid
+ *
+ * Gets a link name for the given UUID. Useful for the settings plugins that
+ * wish to write configuration files compatible with tooling that can't
+ * interpret our UUIDs.
+ *
+ * Returns: An interface name; %NULL if none matches
+ */
+const char *
+nm_manager_iface_for_uuid (NMManager *self, const char *uuid)
+{
+	NMManagerPrivate *priv = NM_MANAGER_GET_PRIVATE (self);
+	NMSettingsConnection *connection;
+
+	connection = nm_settings_get_connection_by_uuid (priv->settings, uuid);
+	if (!connection)
+		return NULL;
+
+	return nm_connection_get_interface_name (NM_CONNECTION (connection));
+}
+
 /**
  * system_create_virtual_device:
  * @self: the #NMManager

src/nm-manager.h

@@ -103,6 +103,9 @@ char *              nm_manager_get_connection_iface (NMManager *self,
                                                      NMDevice **out_parent,
                                                      GError **error);
 
+const char *        nm_manager_iface_for_uuid          (NMManager *self,
+                                                        const char *uuid);
+
 NMActiveConnection *nm_manager_activate_connection     (NMManager *manager,
                                                         NMSettingsConnection *connection,
                                                         NMConnection *applied_connection,

src/settings/plugins/ifcfg-rh/nms-ifcfg-rh-reader.c

@@ -231,7 +231,9 @@ make_connection_setting (const char *file,
 		g_strfreev (items);
 	}
 
-	value = svGetValueString (ifcfg, "BRIDGE");
+	value = svGetValueString (ifcfg, "BRIDGE_UUID");
+	if (!value)
+		value = svGetValueString (ifcfg, "BRIDGE");
 	if (value) {
 		const char *old_value;
 
@@ -1670,7 +1672,10 @@ check_if_bond_slave (shvarFile *ifcfg,
 {
 	char *value;
 
-	value = svGetValueString (ifcfg, "MASTER");
+	value = svGetValueString (ifcfg, "MASTER_UUID");
+	if (!value)
+		value = svGetValueString (ifcfg, "MASTER");
+
 	if (value) {
 		g_object_set (s_con, NM_SETTING_CONNECTION_MASTER, value, NULL);
 		g_object_set (s_con,
@@ -1690,9 +1695,12 @@ check_if_team_slave (shvarFile *ifcfg,
 {
 	gs_free char *value = NULL;
 
-	value = svGetValueString (ifcfg, "TEAM_MASTER");
+	value = svGetValueString (ifcfg, "TEAM_MASTER_UUID");
+	if (!value)
+		value = svGetValueString (ifcfg, "TEAM_MASTER");
 	if (!value)
 		return FALSE;
+
 	g_object_set (s_con, NM_SETTING_CONNECTION_MASTER, value, NULL);
 	g_object_set (s_con, NM_SETTING_CONNECTION_SLAVE_TYPE, NM_SETTING_TEAM_SETTING_NAME, NULL);
 	return TRUE;
@@ -4646,7 +4654,9 @@ make_bridge_port_setting (shvarFile *ifcfg)
 
 	g_return_val_if_fail (ifcfg != NULL, FALSE);
 
-	value = svGetValueString (ifcfg, "BRIDGE");
+	value = svGetValueString (ifcfg, "BRIDGE_UUID");
+	if (!value)
+		value = svGetValueString (ifcfg, "BRIDGE");
 	if (value) {
 		g_free (value);
 

src/settings/plugins/ifcfg-rh/nms-ifcfg-rh-writer.c

@@ -32,6 +32,7 @@
 #include <unistd.h>
 #include <stdio.h>
 
+#include "nm-manager.h"
 #include "nm-setting-connection.h"
 #include "nm-setting-wired.h"
 #include "nm-setting-wireless.h"
@@ -1741,13 +1742,9 @@ write_connection_setting (NMSettingConnection *s_con, shvarFile *ifcfg)
 {
 	guint32 n, i;
 	GString *str;
-	const char *master, *type;
+	const char *master, *master_iface = NULL, *type;
 	char *tmp;
 	gint i_int;
-	const char *v_master = NULL;
-	const char *v_slave = NULL;
-	const char *v_bridge = NULL;
-	const char *v_team_master = NULL;
 
 	svSetValueString (ifcfg, "NAME", nm_setting_connection_get_id (s_con));
 	svSetValueString (ifcfg, "UUID", nm_setting_connection_get_uuid (s_con));
@@ -1815,27 +1812,45 @@ write_connection_setting (NMSettingConnection *s_con, shvarFile *ifcfg)
 
 	svSetValueString (ifcfg, "ZONE", nm_setting_connection_get_zone(s_con));
 
+	svSetValueString (ifcfg, "MASTER_UUID", NULL);
+	svSetValueString (ifcfg, "MASTER", NULL);
+	svSetValueString (ifcfg, "SLAVE", NULL);
+	svSetValueString (ifcfg, "BRIDGE_UUID", NULL);
+	svSetValueString (ifcfg, "BRIDGE", NULL);
+	svSetValueString (ifcfg, "TEAM_MASTER_UUID", NULL);
+	svSetValueString (ifcfg, "TEAM_MASTER", NULL);
+
 	master = nm_setting_connection_get_master (s_con);
 	if (master) {
+		/* The reader prefers the *_UUID variants, however we still try to resolve
+		 * it into an interface name, so that legacy tooling is not confused. */
+		if (!nm_utils_get_testing ()) {
+			/* This is conditional for easier testing. */
+			master_iface = nm_manager_iface_for_uuid (nm_manager_get (), master);
+		}
+		if (!master_iface) {
+			master_iface = master;
+			master = NULL;
+
+		}
+
 		if (nm_setting_connection_is_slave_type (s_con, NM_SETTING_BOND_SETTING_NAME)) {
-			v_master = master;
+			svSetValueString (ifcfg, "MASTER_UUID", master);
-			v_slave = "yes";
+			svSetValueString (ifcfg, "MASTER", master_iface);
-		} else if (nm_setting_connection_is_slave_type (s_con, NM_SETTING_BRIDGE_SETTING_NAME))
+			svSetValueString (ifcfg, "SLAVE", "yes");
-			v_bridge = master;
+		} else if (nm_setting_connection_is_slave_type (s_con, NM_SETTING_BRIDGE_SETTING_NAME)) {
-		else if (nm_setting_connection_is_slave_type (s_con, NM_SETTING_TEAM_SETTING_NAME)) {
+			svSetValueString (ifcfg, "BRIDGE_UUID", master);
-			v_team_master = master;
+			svSetValueString (ifcfg, "BRIDGE", master_iface);
+		} else if (nm_setting_connection_is_slave_type (s_con, NM_SETTING_TEAM_SETTING_NAME)) {
+			svSetValueString (ifcfg, "TEAM_MASTER_UUID", master);
+			svSetValueString (ifcfg, "TEAM_MASTER", master_iface);
 			svUnsetValue (ifcfg, "TYPE");
 		}
 	}
 
-	svSetValueString (ifcfg, "MASTER", v_master);
-	svSetValueString (ifcfg, "SLAVE", v_slave);
-	svSetValueString (ifcfg, "BRIDGE", v_bridge);
-	svSetValueString (ifcfg, "TEAM_MASTER", v_team_master);
-
 	if (nm_streq0 (type, NM_SETTING_TEAM_SETTING_NAME))
 		svSetValueString (ifcfg, "DEVICETYPE", TYPE_TEAM);
-	else if (master && nm_setting_connection_is_slave_type (s_con, NM_SETTING_TEAM_SETTING_NAME))
+	else if (master_iface && nm_setting_connection_is_slave_type (s_con, NM_SETTING_TEAM_SETTING_NAME))
 		svSetValueString (ifcfg, "DEVICETYPE", TYPE_TEAM_PORT);
 	else
 		svUnsetValue (ifcfg, "DEVICETYPE");