OpenWrt DDNS service watchdog. Auto restart service when it exited unexpectedly.

ddns_watchdog.sh

#!/bin/sh
# Run this script from cron every 10 minutes:
# echo '*/10 * * * * /path/to/ddns_watchdog.sh' >> /etc/crontabs/root

. /lib/functions.sh

handle_ddns_service() {
    local cfg="$1"
    local enabled

    config_get enabled "${cfg}" enabled
    [ $enabled != "1" ] && return 0;

    pid=`cat /tmp/run/ddns/$cfg.pid`
    [ -n "$(ps | awk '{print $1}' | grep $pid)" ] && return 0;

    logger -t "ddns_monitor" "service $cfg not running. launching..."
    /bin/sh /usr/lib/ddns/dynamic_dns_updater.sh -v 0 -S $cfg -- start &
}

config_load ddns
config_foreach handle_ddns_service service