ifcfg-rh: fix handling of VLAN parent PHYSDEV key

The initscripts do this:

    MATCH='^.+\.[0-9]{1,4}$'
    if [[ "${DEVICE}" =~ $MATCH ]]; then
	VID=$(echo "${DEVICE}" | LC_ALL=C sed 's/^.*\.\([0-9]\+\)/\1/')
	PHYSDEV=${DEVICE%.*}
    fi
    MATCH='^vlan[0-9]{1,4}?'
    if [[ "${DEVICE}" =~ $MATCH ]]; then
	VID=$(echo "${DEVICE}" | LC_ALL=C sed 's/^vlan0*//')
	# PHYSDEV should be set in ifcfg-vlan* file
	if test -z "$PHYSDEV"; then
		net_log $"PHYSDEV should be set for device ${DEVICE}"
		exit 1
	fi
    fi

which means that if the VLAN name starts with "vlan" then
PHYSDEV must be set, otherwise the parent interface cannot
be determined.

Since PHYSDEV, if set, reflects the explicit intentions of the
user instead of assuming the name from DEVICE, make PHYSDEV
take precedence over determining the parent interface from
heuristics.

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

@@ -4123,13 +4123,25 @@ make_vlan_setting (shvarFile *ifcfg,
 
 	s_vlan = NM_SETTING_VLAN (nm_setting_vlan_new ());
 
+	/* Parent interface from PHYSDEV takes precedence if it exists */
+	parent = svGetValue (ifcfg, "PHYSDEV", FALSE);
+
 	if (iface_name) {
 		g_object_set (s_vlan, NM_SETTING_VLAN_INTERFACE_NAME, iface_name, NULL);
 
 		p = strchr (iface_name, '.');
 		if (p) {
-			/* eth0.43; PHYSDEV is assumed from it */
-			parent = g_strndup (iface_name, p - iface_name);
+			/* eth0.43; PHYSDEV is assumed from it if unknown */
+			if (!parent) {
+				parent = g_strndup (iface_name, p - iface_name);
+				if (g_str_has_prefix (parent, "vlan")) {
+					/* Like initscripts, if no PHYSDEV and we get an obviously
+					 * invalid parent interface from DEVICE, fail.
+					 */
+					g_free (parent);
+					parent = NULL;
+				}
+			}
 			p++;
 		} else {
 			/* format like vlan43; PHYSDEV or MASTER must be set */
@@ -4158,8 +4170,6 @@ make_vlan_setting (shvarFile *ifcfg,
 	}
 	g_object_set (s_vlan, NM_SETTING_VLAN_ID, vlan_id, NULL);
 
-	if (!parent)
-		parent = svGetValue (ifcfg, "PHYSDEV", FALSE);
 	if (parent == NULL) {
 		g_set_error_literal (error, IFCFG_PLUGIN_ERROR, 0,
 		                     "Failed to determine VLAN parent from DEVICE or PHYSDEV");

src/settings/plugins/ifcfg-rh/tests/network-scripts/Makefile.am

@@ -85,6 +85,7 @@ EXTRA_DIST = \
 	ifcfg-test-vlan-interface \
 	ifcfg-test-vlan-only-vlanid \
 	ifcfg-test-vlan-only-device \
+	ifcfg-test-vlan-physdev \
 	ifcfg-test-wifi-wep-no-keys \
 	ifcfg-test-permissions \
 	ifcfg-test-wifi-wep-agent-keys \

src/settings/plugins/ifcfg-rh/tests/network-scripts/ifcfg-test-vlan-physdev

@@ -0,0 +1,6 @@
+VLAN=yes
+TYPE=Vlan
+DEVICE=vlan0.3
+PHYSDEV=eth0
+VLAN_ID=3
+

src/settings/plugins/ifcfg-rh/tests/test-ifcfg-rh.c

@@ -11504,6 +11504,30 @@ test_read_vlan_only_device (void)
 	g_object_unref (connection);
 }
 
+static void
+test_read_vlan_physdev (void)
+{
+	NMConnection *connection;
+	GError *error = NULL;
+	NMSettingVlan *s_vlan;
+
+	connection = connection_from_file (TEST_IFCFG_DIR"/network-scripts/ifcfg-test-vlan-physdev",
+	                                   NULL, TYPE_ETHERNET, NULL, NULL,
+	                                   NULL, NULL, NULL, &error, NULL);
+	g_assert_no_error (error);
+	g_assert (connection);
+	g_assert (nm_connection_verify (connection, &error));
+
+	s_vlan = nm_connection_get_setting_vlan (connection);
+	g_assert (s_vlan);
+
+	g_assert_cmpstr (nm_setting_vlan_get_interface_name (s_vlan), ==, "vlan0.3");
+	g_assert_cmpstr (nm_setting_vlan_get_parent (s_vlan), ==, "eth0");
+	g_assert_cmpint (nm_setting_vlan_get_id (s_vlan), ==, 3);
+
+	g_object_unref (connection);
+}
+
 static void
 test_write_vlan (void)
 {
@@ -12515,6 +12539,7 @@ int main (int argc, char **argv)
 	test_read_vlan_interface ();
 	test_read_vlan_only_vlan_id ();
 	test_read_vlan_only_device ();
+	g_test_add_func (TPATH "vlan/physdev", test_read_vlan_physdev);
 
 	test_write_wired_static ();
 	test_write_wired_static_ip6_only ();