From 2dac1bcdc969a940fa34396db89ae3f1f2a3073f Mon Sep 17 00:00:00 2001
From: Florian Eckert <fe@dev.tdt.de>
Date: Wed, 22 Jul 2020 09:19:55 +0200
Subject: [PATCH] mwan3: fix race condition on mwan3 restart

This adjustment of the locks fixes the race condition when a mwan3
hotplug script and a mwan3 command are running at the same time.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>
---
 net/mwan3/files/etc/hotplug.d/iface/15-mwan3  | 14 +++++++-----
 net/mwan3/files/etc/hotplug.d/iface/16-mwan3  | 11 +++++++---
 .../files/etc/hotplug.d/iface/16-mwan3-user   | 16 ++++++++++++--
 net/mwan3/files/usr/sbin/mwan3                | 22 ++++++++++++++-----
 4 files changed, 47 insertions(+), 16 deletions(-)

diff --git a/net/mwan3/files/etc/hotplug.d/iface/15-mwan3 b/net/mwan3/files/etc/hotplug.d/iface/15-mwan3
index 5bfbd24624..db2dc237a9 100644
--- a/net/mwan3/files/etc/hotplug.d/iface/15-mwan3
+++ b/net/mwan3/files/etc/hotplug.d/iface/15-mwan3
@@ -12,19 +12,24 @@ if [ "$ACTION" == "ifup" ]; then
         [ -n "$DEVICE" ] || exit 3
 fi
 
+mwan3_lock "$ACTION" "$INTERFACE"
 config_load mwan3
 config_get_bool enabled globals 'enabled' '0'
-[ ${enabled} -gt 0 ] || exit 0
+[ ${enabled} -gt 0 ] || {
+	mwan3_unlock "$ACTION" "$INTERFACE"
+	exit 0
+}
 
-mwan3_lock "$ACTION" "$INTERFACE"
 mwan3_init
 mwan3_set_connected_iptables
 mwan3_set_custom_ipset
-mwan3_unlock "$ACTION" "$INTERFACE"
 
 config_get enabled $INTERFACE enabled 0
 config_get initial_state $INTERFACE initial_state "online"
-[ "$enabled" == "1" ] || exit 0
+[ "${enabled}" == "1" ] || {
+	mwan3_unlock "$ACTION" "$INTERFACE"
+	exit 0
+}
 
 if [ "$ACTION" == "ifup" ]; then
 	config_get family $INTERFACE family ipv4
@@ -58,7 +63,6 @@ else
 	running=1
 fi
 
-mwan3_lock "$ACTION" "$INTERFACE"
 $LOG notice "Execute "$ACTION" event on interface $INTERFACE (${DEVICE:-unknown})"
 
 case "$ACTION" in
diff --git a/net/mwan3/files/etc/hotplug.d/iface/16-mwan3 b/net/mwan3/files/etc/hotplug.d/iface/16-mwan3
index c243d55ff8..d68401fedc 100644
--- a/net/mwan3/files/etc/hotplug.d/iface/16-mwan3
+++ b/net/mwan3/files/etc/hotplug.d/iface/16-mwan3
@@ -4,14 +4,17 @@
 . /lib/functions/network.sh
 . /lib/mwan3/mwan3.sh
 
+mwan3_lock "$ACTION" "mwan3rtmon"
+
 config_load mwan3
 config_get_bool enabled globals 'enabled' '0'
-[ ${enabled} -gt 0 ] || exit 0
+[ ${enabled} -gt 0 ] || {
+	mwan3_unlock "$ACTION" "mwan3rtmon"
+	exit 0
+}
 
 if [ "$ACTION" == "ifup" ]; then
-	mwan3_lock "$ACTION" "mwan3rtmon"
 	mwan3_rtmon
-	mwan3_unlock "$ACTION" "mwan3rtmon"
 fi
 
 config_get enabled $INTERFACE enabled 0
@@ -19,4 +22,6 @@ config_get enabled $INTERFACE enabled 0
 	mwan3_flush_conntrack "$INTERFACE" "$ACTION"
 }
 
+mwan3_unlock "$ACTION" "mwan3rtmon"
+
 exit 0
diff --git a/net/mwan3/files/etc/hotplug.d/iface/16-mwan3-user b/net/mwan3/files/etc/hotplug.d/iface/16-mwan3-user
index 9372c736e1..ef490e1833 100644
--- a/net/mwan3/files/etc/hotplug.d/iface/16-mwan3-user
+++ b/net/mwan3/files/etc/hotplug.d/iface/16-mwan3-user
@@ -2,13 +2,25 @@
 
 [ -f "/etc/mwan3.user" ] && {
 	. /lib/functions.sh
+	. /lib/mwan3/mwan3.sh
+
+	mwan3_lock "$ACTION" "user"
 
 	config_load mwan3
 	config_get_bool enabled globals 'enabled' '0'
-	[ ${enabled} -gt 0 ] || exit 0
+	[ ${enabled} -gt 0 ] || {
+		mwan3_unlock "$ACTION" "user"
+		exit 0
+	}
 
 	config_get enabled "$INTERFACE" enabled 0
-	[ "${enabled}" = "1" ] || exit 0
+	[ "${enabled}" = "1" ] || {
+		mwan3_unlock "$ACTION" "user"
+		exit 0
+	}
+
+	mwan3_unlock "$ACTION" "user"
+
 	env -i ACTION="$ACTION" INTERFACE="$INTERFACE" DEVICE="$DEVICE" \
 		/bin/sh /etc/mwan3.user
 }
diff --git a/net/mwan3/files/usr/sbin/mwan3 b/net/mwan3/files/usr/sbin/mwan3
index b9a5afb9e4..dc65279bec 100755
--- a/net/mwan3/files/usr/sbin/mwan3
+++ b/net/mwan3/files/usr/sbin/mwan3
@@ -45,30 +45,39 @@ ifup()
 {
 	local device enabled up l3_device status
 
+	mwan3_lock "command" "mwan3"
+
 	config_load mwan3
 	config_get_bool enabled globals 'enabled' 0
+
 	[ ${enabled} -gt 0 ] || {
 		echo "The service mwan3 is global disabled."
 		echo "Please execute \"/etc/init.d/mwan3 start\" first."
+		mwan3_unlock "command" "mwan3"
 		exit 1
 	}
 
 	if [ -z "$1" ]; then
-		echo "Expecting interface. Usage: mwan3 ifup <interface>" && exit 0
+		echo "Expecting interface. Usage: mwan3 ifup <interface>"
+		mwan3_unlock "command" "mwan3"
+		exit 0
 	fi
 
 	if [ -n "$2" ]; then
-		echo "Too many arguments. Usage: mwan3 ifup <interface>" && exit 0
+		echo "Too many arguments. Usage: mwan3 ifup <interface>"
+		mwan3_unlock "command" "mwan3"
+		exit 0
 	fi
 
+	config_get enabled "$1" enabled 0
+	mwan3_unlock "command" "mwan3"
+
 	status=$(ubus -S call network.interface.$1 status)
 	[ -n "$status" ] && {
 		json_load "$status"
 		json_get_vars up l3_device
 	}
 
-	config_get enabled "$1" enabled 0
-
 	if [ "$up" = "1" ] \
 		&& [ -n "$l3_device" ] \
 		&& [ "$enabled" = "1" ]; then
@@ -130,7 +139,9 @@ start()
 {
 	local enabled
 
+	mwan3_lock "command" "mwan3"
 	uci_toggle_state mwan3 globals enabled "1"
+	mwan3_unlock "command" "mwan3"
 
 	config_load mwan3
 	config_foreach ifup interface
@@ -141,6 +152,7 @@ stop()
 	local ipset route rule table IP IPT pid
 
 	mwan3_lock "command" "mwan3"
+	uci_toggle_state mwan3 globals enabled "0"
 
 	for pid in $(pgrep -f "mwan3rtmon"); do
 		kill -TERM "$pid" > /dev/null 2>&1
@@ -200,8 +212,6 @@ stop()
 
 	mwan3_lock_clean
 	rm -rf $MWAN3_STATUS_DIR $MWAN3TRACK_STATUS_DIR
-
-	uci_toggle_state mwan3 globals enabled "0"
 }
 
 restart() {
-- 
2.30.2