mwan3: use procd for locking everywhere

Replace locks on /var/run/mwan3.lock with locks via procd.

This fixes a deadlock issue where mwan3 stop would have a procd
lock, but a hotplug script would have the /var/run/mwan3.lock

Locking can be removed from mwan3rtmon since:
1) procd will have sent the KILL signal to the process during
shutdown, so it will not add routes to already removed interfaces on
mwan3 shutdown and
2) mwan3rtmon checks if an interface is active based on the
mwan3_iface_in_<IFACE> entry in iptables, and the hotplug script
always adds this before creating the route table and removes it
before deleting the route table

Fixes github issue #13704
(https://github.com/openwrt/packages/issues/13704)

5 files changed, 9 insertions, 35 deletions

diff --git a/net/mwan3/files/etc/hotplug.d/iface/15-mwan3 b/net/mwan3/files/etc/hotplug.d/iface/15-mwan3
index 5c60128d4..5fe3e33e0 100644
--- a/net/mwan3/files/etc/hotplug.d/iface/15-mwan3
+++ b/net/mwan3/files/etc/hotplug.d/iface/15-mwan3
@@ -5,6 +5,10 @@
 . /lib/mwan3/mwan3.sh
 . /lib/mwan3/common.sh
 
+initscript=/etc/init.d/mwan3
+. /lib/functions/procd.sh
+
+
 SCRIPTNAME="mwan3-hotplug"
 [ "$ACTION" = "ifup" ] || [ "$ACTION" = "ifdown" ] || [ "$ACTION" = "connected" ] || [ "$ACTION" = "disconnected" ] || exit 1
 [ -n "$INTERFACE" ] || exit 2
@@ -15,18 +19,17 @@ if { [ "$ACTION" = "ifup" ] || [ "$ACTION" = "connected" ] ; } && [ -z "$DEVICE"
 	exit 3
 fi
 
-[ "$MWAN3_STARTUP" = 1 ] || mwan3_lock "$ACTION" "$INTERFACE"
+[ "$MWAN3_STARTUP" = 1 ] || procd_lock
 
 config_load mwan3
 /etc/init.d/mwan3 running || {
-	[ "$MWAN3_STARTUP" = 1 ] || mwan3_unlock "$ACTION" "$INTERFACE"
+	[ "$MWAN3_STARTUP" = 1 ] || procd_lock
 	LOG notice "mwan3 hotplug $ACTION on $INTERFACE not called because globally disabled"
 	mwan3_flush_conntrack "$INTERFACE" "$ACTION"
 	exit 0
 }
 
 $IPT4 -S mwan3_hook &>/dev/null || {
-	mwan3_unlock "$ACTION" "$INTERFACE"
 	LOG warn "hotplug called on $INTERFACE before mwan3 has been set up"
 	exit 0
 }
@@ -43,7 +46,6 @@ fi
 
 config_get_bool enabled $INTERFACE 'enabled' '0'
 [ "${enabled}" -eq 1 ] || {
-	[ "$MWAN3_STARTUP" = 1 ] || mwan3_unlock "$ACTION" "$INTERFACE"
 	LOG notice "mwan3 hotplug on $INTERFACE not called because interface disabled"
 	exit 0
 }
@@ -56,11 +58,6 @@ else
 	status=online
 fi
 
-if [ "$ACTION" = ifup ] || [ "$ACTION" = ifdown ]; then
-	initscript=/etc/init.d/mwan3
-	. /lib/functions/procd.sh
-fi
-
 LOG notice "Execute $ACTION event on interface $INTERFACE (${DEVICE:-unknown})"
 
 case "$ACTION" in
@@ -93,5 +90,4 @@ case "$ACTION" in
 		mwan3_set_policies_iptables
 	;;
 esac
-[ "$MWAN3_STARTUP" = 1 ] || mwan3_unlock "$ACTION" "$INTERFACE"
 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 698fe0909..be857e8ff 100644
--- a/net/mwan3/files/etc/hotplug.d/iface/16-mwan3-user
+++ b/net/mwan3/files/etc/hotplug.d/iface/16-mwan3-user
@@ -3,11 +3,12 @@
 [ -f "/etc/mwan3.user" ] && {
 	. /lib/functions.sh
 	. /lib/mwan3/mwan3.sh
+        initscript=/etc/init.d/mwan3
+	. /lib/functions/procd.sh
 
-	[ "$MWAN3_SHUTDOWN" != 1 ] && mwan3_lock "$ACTION" "$DEVICE-user"
+	[ "$MWAN3_SHUTDOWN" != 1 ] && procd_lock
 
 	[ "$MWAN3_SHUTDOWN" != 1 ] && ! /etc/init.d/mwan3 running && {
-		mwan3_unlock "$ACTION" "$DEVICE-user"
 		exit 0
 	}
 
@@ -19,8 +20,6 @@
 		exit 0
 	}
 
-	[ "$MWAN3_SHUTDOWN" != 1 ] && mwan3_unlock "$ACTION" "$DEVICE-user"
-
 	env -i ACTION="$ACTION" INTERFACE="$INTERFACE" DEVICE="$DEVICE" \
 		/bin/sh /etc/mwan3.user
 }
diff --git a/net/mwan3/files/etc/init.d/mwan3 b/net/mwan3/files/etc/init.d/mwan3
index b7cf91eb1..bd1ea7260 100644
--- a/net/mwan3/files/etc/init.d/mwan3
+++ b/net/mwan3/files/etc/init.d/mwan3
@@ -31,8 +31,6 @@ start_service() {
 	mwan3_init
 	config_foreach start_tracker interface
 
-	mwan3_lock "command" "mwan3"
-
 	mwan3_update_iface_to_table
 	mwan3_set_connected_ipset
 	mwan3_set_custom_ipset
@@ -43,8 +41,6 @@ start_service() {
 	mwan3_set_policies_iptables
 	mwan3_set_user_rules
 
-	mwan3_unlock "command" "mwan3"
-
 	procd_open_instance rtmon_ipv4
 	procd_set_param command /usr/sbin/mwan3rtmon ipv4
 	procd_set_param respawn
@@ -61,8 +57,6 @@ start_service() {
 stop_service() {
 	local ipset rule IP IPTR IPT family table tid
 
-	mwan3_lock "command" "mwan3"
-
 	config_load mwan3
 	mwan3_init
 	config_foreach mwan3_interface_shutdown interface
@@ -108,7 +102,6 @@ stop_service() {
 
 	rm -rf $MWAN3_STATUS_DIR $MWAN3TRACK_STATUS_DIR
 
-	mwan3_unlock "command" "mwan3"
 }
 
 reload_service() {
diff --git a/net/mwan3/files/lib/mwan3/mwan3.sh b/net/mwan3/files/lib/mwan3/mwan3.sh
index e6e43ebe8..8a5fe6f0d 100644
--- a/net/mwan3/files/lib/mwan3/mwan3.sh
+++ b/net/mwan3/files/lib/mwan3/mwan3.sh
@@ -103,16 +103,6 @@ mwan3_count_one_bits()
 	echo $count
 }
 
-mwan3_lock() {
-	lock /var/run/mwan3.lock
-	#LOG debug "$1 $2 (lock)"
-}
-
-mwan3_unlock() {
-	#LOG debug "$1 $2 (unlock)"
-	lock -u /var/run/mwan3.lock
-}
-
 mwan3_get_iface_id()
 {
 	local _tmp
diff --git a/net/mwan3/files/usr/sbin/mwan3rtmon b/net/mwan3/files/usr/sbin/mwan3rtmon
index 569b4d172..6ece58125 100644
--- a/net/mwan3/files/usr/sbin/mwan3rtmon
+++ b/net/mwan3/files/usr/sbin/mwan3rtmon
@@ -159,16 +159,13 @@ main()
 		IP="$IP4"
 	fi
 	mwan3_init
-	mwan3_lock "mwan3rtmon" "start"
 	sh -c "echo \$\$; exec $IP monitor route" | {
 		read -r monitor_pid
 		trap_with_arg func_trap "$monitor_pid" SIGINT SIGTERM SIGKILL
 		while IFS='' read -r line; do
 			[ -z "${line##*table*}" ] && continue
 			LOG debug "handling route update $family '$line'"
-			mwan3_lock "service" "mwan3rtmon"
 			mwan3_rtmon_route_handle "$line" "$family"
-			mwan3_unlock "service" "mwan3rtmon"
 		done
 	} &
 	child=$!
@@ -176,7 +173,6 @@ main()
 	trap_with_arg func_trap "$child" SIGINT SIGTERM SIGKILL
 	mwan3_set_connected_${family}
 	mwan3_add_all_routes ${family}
-	mwan3_unlock "mwan3rtmon" "start"
 	kill -SIGCONT $child
 	wait $!
 }