#!/bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin

#constants
START_PORT=10000
PORTS_PER_UML=1000
VOLUME=/dev/vg1
UML_HOME_BASE=/var/local
KERNEL=/opt/uml/bin/linux

if [ "$1" = "--nice" ]; then
	NICE="nice"
	shift
else
	NICE=""
fi
UMLUSER=$1
IP_LAST_NR=$2
MEM=$3
DISKSPACE=$4
OP=$5
UMLIP=192.168.3.$IP_LAST_NR
SSHPORT=$(($START_PORT + $IP_LAST_NR * $PORTS_PER_UML + 22))
TAPDEV=tap$IP_LAST_NR
UMLHOME=$UML_HOME_BASE/$UMLUSER
PARTITION=$VOLUME/$UMLUSER

NAME=UML-$UMLUSER
DESC="UML $UMLIP Instanz"
MEMORY="mem=$MEM"
UMID="umid=$UMLUSER"
NETWORK="eth0=tuntap,$TAPDEV"
DISKS="ubd0=$PARTITION"
CONSOLES='con0=fd:0,fd:1 con=pts'

set -e
case "$OP" in
	start)
		echo -n "starting $DESC $NAME"
		test -d $UMLHOME || mkdir $UMLHOME
		chown $UMLUSER $UMLHOME
		tunctl -u $UMLUSER -t $TAPDEV > /dev/null
		ifconfig $TAPDEV up
		brctl addif br0 $TAPDEV
		chown $UMLUSER $PARTITION
		/usr/bin/screen -d -m -- su -c "HOME=$UMLHOME $NICE $KERNEL $MEMORY $UMID $NETWORK $DISKS $CONSOLES" $UMLUSER
		iptables -t nat -A POSTROUTING -o eth0 -s $UMLIP -j MASQUERADE
		iptables -t nat -A PREROUTING -p tcp --dport $SSHPORT -j DNAT --to-destination $UMLIP:22
		echo "."
	;;
	stop)
		echo -n "stopping $DESC $NAME "
		su -c "HOME=$UMLHOME /usr/bin/uml_mconsole $UMLUSER cad" $UMLUSER
		# wait doesn't wait for foreign childs 
		#that's why the following doesn't work:
		#wait `cat $UMLHOME/.uml/$UMLUSER/pid`
		#instead we loop 10 times to check whether the process terminated
		TESTCMD="ps `cat $UMLHOME/.uml/$UMLUSER/pid`"
		for ((i=1; i <= 20 ; i++)) do
			$TESTCMD > /dev/null && sleep 1
		done
		if $TESTCMD > /dev/null ; then 
			echo UML instance did not terminate. To kill it type
			echo su -c \"HOME=$UMLHOME /usr/bin/uml_mconsole $UMLUSER halt\" $UMLUSER
			exit 1
		fi
		iptables -t nat -D POSTROUTING -o eth0 -s $UMLIP -j MASQUERADE
		iptables -t nat -D PREROUTING -p tcp --dport $SSHPORT -j DNAT --to-destination $UMLIP:22
		brctl delif br0 $TAPDEV
		ifconfig $TAPDEV down
		tunctl -d $TAPDEV > /dev/null
		#rmdir $UMLHOME
		echo "."
	;;
        restart)
                $0 $NICE $1 $2 $3 stop
                delay 100
                $0 $NICE $1 $2 $3 start
        ;;
	backup)
                if [ -b $VOLUME/$UMLUSER-backup ]; then
			echo "backup-partition already exists. Please rename/delete it first" >&2
			exit 1
		fi
		su -c "HOME=$UMLHOME /usr/bin/uml_mconsole $UMLUSER stop" $UMLUSER
		su -c "HOME=$UMLHOME /usr/bin/uml_mconsole $UMLUSER sysrq s" $UMLUSER
		lvcreate -L $DISKSPACE -s -n $UMLUSER-backup $VOLUME/$UMLUSER
		su -c "HOME=$UMLHOME /usr/bin/uml_mconsole $UMLUSER go" $UMLUSER
	;;
	*)
		N=/etc/init.d/$NAME
		echo "Usage: $N {start|stop|restart|backup}" >&2
		exit 1
	;;
esac
exit 0