$NetBSD: patch-tools_hotplug_NetBSD_vif-ip,v 1.1 2018/07/24 13:40:11 bouyer Exp $

--- tools/hotplug/NetBSD/vif-ip.orig	2015-01-12 17:53:24.000000000 +0100
+++ tools/hotplug/NetBSD/vif-ip	2015-01-19 13:16:37.000000000 +0100
@@ -24,6 +24,10 @@
 	xfid=$(xenstore-read "$xpath/frontend-id")
 	xhandle=$(xenstore-read "$xpath/handle")
 	iface=$(xenstore-read "$xpath/vifname")
+	iface=$(xenstore-read "$xpath/vifname") || true
+	if [ x${iface} = "x" ] ; then
+		iface=xvif$xfid.$xhandle
+	fi
 	ifconfig $iface $xip up
 	xenstore-write $xpath/hotplug-status connected
 	exit 0
