#!/bin/bash
#
# plc	Manages all PLC services on this machine
#
# chkconfig: 2345 99 5
#
# description:	Manages all PLC services on this machine
#
# $Id$
#

PATH=/sbin:/bin:/usr/bin:/usr/sbin

# Source function library.
if [ -f /etc/init.d/functions ] ; then
    . /etc/init.d/functions
fi

# If success() or failure() are not defined
if ! type -type success >/dev/null || ! type -type failure >/dev/null ; then
    success() {
	echo -ne "[  OK  ]\r"
	return 0
    }
    failure() {
	echo -ne "[FAILED]\r"
	return 1
    }
fi

# Source configuration
SERVICE=$(basename $0)
if [ ! -f /etc/sysconfig/$SERVICE ] ; then
    SERVICE=plc
fi
if [ -f /etc/sysconfig/$SERVICE -a -z "${PLC_ROOT}${PLC_DATA}" ] ; then
    . /etc/sysconfig/$SERVICE
fi

# Total number of errors
ERRORS=0

# Count the exit status of the last command
check ()
{
    ERRORS=$(($ERRORS+$?))
}

mounted ()
{
    if cut -d' ' -f2 /proc/mounts | grep -q "$1" ; then
	return 0
    else
	return 1
    fi
}

mount_plc ()
{
    echo -n $"Mounting PLC: "

    if ! mounted $PLC_ROOT ; then
	if ! e2fsck -a $PLC_ROOT.img | logger -t "PLC" ; then
	    e2fsck $PLC_ROOT.img
	fi
	mount -o loop $PLC_ROOT.img $PLC_ROOT
	check
    fi
    if ! mounted $PLC_ROOT/data ; then
	mount -t none -o bind,rw $PLC_DATA $PLC_ROOT/data
	check
    fi
    if ! mounted $PLC_ROOT/proc ; then
	mount -t proc none $PLC_ROOT/proc
	check
    fi

    [ $ERRORS -eq 0 ] && success $"PLC unmount" || failure $"PLC unmount"	
    echo

}

start ()
{
    # Starting everything
    if [ -z "$1" ] ; then
	mount_plc 
    fi

    chroot $PLC_ROOT /sbin/service plc $PLC_OPTIONS start $*
    check
}

umount_plc ()
{
    echo -n $"Unmounting PLC: "

    for dir in $PLC_ROOT/proc $PLC_ROOT/data $PLC_ROOT ; do
	if mounted $dir ; then
	    umount $dir
	    check
	fi
    done

    [ $ERRORS -eq 0 ] && success $"PLC unmount" || failure $"PLC unmount"	
    echo
}

stop ()
{
    if mounted $PLC_ROOT ; then
	chroot $PLC_ROOT /sbin/service plc $PLC_OPTIONS stop $*
	check
    fi

    # Stopped everything
    if [ -z "$1" ] ; then
	umount_plc
    fi
}

mountstatus_plc ()
{
    for dir in $PLC_ROOT/proc $PLC_ROOT/data $PLC_ROOT ; do
	if mounted $dir ; then
	    echo $dir
	fi
    done
}

# safestop : tries to stop normally; if that fails, kills processes that are still using /plc 
# needs the lsof rpm in the root context (should be a dependency of the myplc spec)
function check_command ()
{
    command=$1; shift
    found=$(type -p $command)
    if [ -z "$found" ] ; then
        echo "$COMMAND : requires command $command, was not found - exiting"
	exit 1
    fi
}


### when process stil use /plc/root, we cannot umount it
function kill_all ()
{
    [ -n "$DEBUG" ] && set -x
    check_command lsof
    
    echo -n "Killing processes using $PLC_ROOT and $PLC_DATA: "
    # initialize process list
    former_process_list="unlikely"
      
    # we ignore unknown uids for now, since we run in the chroot jail anyway
    # not too sure about that though, 
    while true; do
        # get the list of processes - collapse and remove empty lines
	process_list=$(lsof -t +D $PLC_ROOT +D $PLC_DATA)
	if [ -z "$process_list" ] ; then
	    # we are done, let's bail out
	    success "$PLC_ROOT clear" ; echo ; return
	fi
	if [ "$process_list" = "$former_process_list" ] ; then
	    # we are stuck, no progress since last time : exit on error
	    failure "$PLC_ROOT locked" ; echo ; return
	fi
	# record for next loop
	former_process_list="$process_list"
	# kill them
	kill $process_list
	sleep 2
	# check there are dead
	for pid in $process_list ; do
	    ps -o pid $pid &> /dev/null 
	    if [ "$?" = 0 ] ; then
	        [ -n "$DEBUG" ] && echo "$pid survived kill - forcing kill -9"
		kill -9 $pid
	    fi
	done
    done
}

# Get command
shift $(($OPTIND - 1))
command=$1

# Get step(s)
shift 1

case "$command" in
    start|stop)
	$command $*
	;;

    restart)
	stop $*
	ERRORS=0
	start $*
	;;

    reload)
	chroot $PLC_ROOT /sbin/service plc $PLC_OPTIONS reload $*
	;;	

    mount|umount|mountstatus)
        ${command}_plc
	;;

   kill)
        kill_all
        ;;

   safestop)
        stop
	### Checking : we might need to run kill
	mounted=$(mountstatus_plc)
	if [ -n "$mounted" ] ; then
	    echo "Umount failed : killing remaining processes and trying again"
	    ERRORS=0
	    kill_all
	    ERRORS=0
	    stop
	fi
	;;
  
    *)
	echo "Usage: $0 {start|stop|restart|reload|mount|umount|mountstatus|kill|safestop}"
	RETVAL=1
	;;
esac

exit $ERRORS