From 902da9f837e9273a2166b0f4b1094b8f5587a5e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Pierret=20=28fepitre=29?=
 <frederic.pierret@qubes-os.org>
Date: Sat, 18 May 2019 10:42:13 +0200
Subject: [PATCH] Handle default value for get_iface_from_mac

---
 init/functions | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/init/functions b/init/functions
index 29573a7..4ed27e6 100644
--- a/init/functions
+++ b/init/functions
@@ -131,7 +131,9 @@ umount_retry() {
 get_iface_from_mac() {
     local mac="$1"
     local iface
-    iface="$(ip -o link | grep -i "$mac" | awk '{print $2}' | cut -d ':' -f1)"
+    if [ "x$mac" != "x" ]; then
+        iface="$(ip -o link | grep -i "$mac" | awk '{print $2}' | cut -d ':' -f1)"
+    fi
     echo "$iface"
 }