#!/bin/bash
#
# tcpresponder      Multi-purpose port listener invoker.
# Ver. 0.9.3
#
# chkconfig: 2345 98 2
# description: Multi-purpose port listener invoker
#
# pidfile: /var/run/tcpresponder.pid

## Basic setup variables.
PROG=$(basename $0)

# tcpserver path
TCPSERVER=/usr/local/bin/tcpserver

[ -f /etc/sysconfig/tcpresponder ] && . /etc/sysconfig/tcpresponder

## Procedures from here.

show_help () {
    cat <<EOM
USAGE: $PROG [-p LISTEN_PORT] {start|stop|status}
where LISTEN_PORT defaults to $DEFAULTPORT.
EOM
    exit 1
}

what_pid () {
    pid=
    pid=$(echo $(ps axw |egrep "tcpserver .* $port " |grep -v grep) |\
      cut -d' ' -f1)
}

while [ $# -gt 0 ]; do
    case $1 in
	-p)
	    shift
	    port=$1
	    ;;
	start|stop|status)
	    action=$1
	    ;;
	*)
	    show_help
	    ;;
    esac
    shift
done

: ${port:=$DEFAULTPORT}
PIDFILE=/var/run/${PROG}_${port}.pid
LOCKFILE=/var/lock/subsys/${PROG}_$port

echo $port |grep -Eq '^[0-9]+$'
[ $? -ne 0 -o -z "$action" ] && show_help

case $action in
    start)
	what_pid
	if [ -n "$pid" ]; then
	    echo "another copy of $PROG running"
	    exit 1
	fi

	$TCPSERVER $TCPOPT $port $TCPCMD &

	sleep 1
	what_pid
	[ -n "$pid" ] || exit 1

	echo $pid >$PIDFILE
	touch $LOCKFILE
	exit 0
	;;
    stop)
	what_pid
	if [ -n "$pid" ]; then
	    kill -TERM $pid
	    if [ $? -eq 0 ]; then
		echo "PID:$pid terminated"
		rm -f $PIDFILE $LOCKFILE
		exit 0
	    fi
	fi

	echo "no such tcpserver process"
	rm -f $PIDFILE $LOCKFILE
	exit 1
	;;
    status)
	read pid listen < <(ps axww |egrep "tcpserver .* $port " |grep -v grep |awk '{ printf("%s %s\n",$1,$(NF-1)); }')

	if [ "x$pid" = "x" ]; then
	    echo $PROG is not running
	else
	    echo "Listening port $listen (PID:$pid)"
	fi

	exit 0
	;;
esac