From 1334553121f1e6a218e8d334d4ed51e9fc2746cc Mon Sep 17 00:00:00 2001
From: Adrien Banlin <a.banlin@alphalink.fr>
Date: Tue, 13 Jun 2023 17:33:35 +0200
Subject: [PATCH] ifupdown2-hotplug: flock and pass fd to ifupdown2

---
 debian/ifupdown2-hotplug | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/debian/ifupdown2-hotplug b/debian/ifupdown2-hotplug
index a2b18115..d0150d6c 100755
--- a/debian/ifupdown2-hotplug
+++ b/debian/ifupdown2-hotplug
@@ -13,6 +13,8 @@ else
 	unset LOGGER
 fi
 
+LOCKFILE=/run/network/.lock
+
 # for diagnostics
 if [ -t 1 -a -z "$LOGGER" ] || [ ! -e '/dev/log' ]; then
 	mesg() {
@@ -48,24 +50,23 @@ wait_for_interface() {
 }
 
 net_ifup() {
-
+    flock 9
     wait_for_interface lo
-
-    if $(ifquery -l --allow=hotplug 2>/dev/null | grep -w -q "^$INTERFACE$"); then
-	exec ifup $INTERFACE --systemd
+    if $(ifquery -L 9 -l --allow=hotplug 2>/dev/null | grep -w -q "^$INTERFACE$"); then
+	exec ifup $INTERFACE -L 9 --systemd
     else
 	mesg "NET $INTERFACE not a hotplug interface"
     fi
-}
+} 9>$LOCKFILE
 
 net_ifdown() {
-
-    if $(ifquery -l --allow=hotplug 2>/dev/null | grep -w -q "^$INTERFACE$"); then
-	exec ifdown $INTERFACE --systemd
+    flock 9
+    if $(ifquery -L 9 -l --allow=hotplug 2>/dev/null | grep -w -q "^$INTERFACE$"); then
+	exec ifdown $INTERFACE -L 9 --systemd
     else
 	mesg "NET $INTERFACE not a hotplug interface"
     fi
-}
+} 9>$LOCKFILE
 
 do_everything() {