Gracefully shutdown UNIX-socket server on NodeJS running under Forever

I have an NodeJS application which sets up a UNIX-socket to expose some interprocess communication channel (some kind of monitoring stuff). UNIX-socket file is placed in os.tmpdir() folder (i.e. /tmp/app-monitor.sock).

var net = require('net');
var server = net.createServer(...);
server.listen('/tmp/app-monitor.sock', ...);

I use a signal handling (SIGINT, SITERM, etc...) to gracefully shutdown my server and remove a socket file.

function shutdown() {
    server.close(); // socket file is automatically removed here
    process.exit();
}

process.on('SIGINT', shutdown);
// and so on

My application is running with forever start ... to monitor it's lifecycle.

I have a problem with forever restartall command. When forever doing restartall it's using a SIGKILL to terminate all child processes. SIGKILL can't be handled by a process so my app dies without any shutdown procedures.

The problem is a socket file which is not removed when SIGKILL is used. After the child process is restarted, new server can't be started cause' a listen call will cause a EADDRINUSE error.

I can't remove a existing socket file during an app startup cause' I don't know if it a real working socket or some traces of a previous unclean shutdown.

So, the question is... What is the better way to handle such situation (SIGKILL and UNIX-socket server)?