#!/bin/sh
### BEGIN INIT INFO
# Provides:          qubes-meminfo-writer
# Required-Start:    $network $local_fs $remote_fs
# Required-Stop:
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: meminfo-writer memory ballooning helper
# Description:       Provides memory ballooning support for qubes AppVMs
### END INIT INFO

# Author: Davíð Steinn Geirsson <david@dsg.is>

PATH=/sbin:/usr/sbin:/bin:/usr/bin
DESC=qubes-meminfo-writer
NAME=meminfo-writer
DAEMON=/usr/sbin/meminfo-writer
MEM_CHANGE_THRESHOLD_KB=30000
MEMINFO_DELAY_USEC=100000
DAEMON_ARGS="$MEM_CHANGE_THRESHOLD_KB $MEMINFO_DELAY_USEC"
PIDFILE=/var/run/$NAME.pid
SCRIPTNAME=/etc/init.d/$NAME

[ -x $DAEMON ] || exit 0

[ -r /etc/default/$NAME ] && . /etc/default/$NAME

. /lib/init/vars.sh

. /lib/lsb/init-functions

#
# Function that starts the daemon/service
#
do_start()
{
	start_meminfo_writer=$(/usr/bin/xenstore-read qubes-service/meminfo-writer 2>/dev/null)
	if [ "$start_meminfo_writer" != "0" ]; then
		/usr/sbin/meminfo-writer $MEM_CHANGE_THRESHOLD_KB $MEMINFO_DELAY_USEC /var/run/meminfo-writer.pid
		start-stop-daemon --start --quiet --pidfile $PIDFILE \
			--exec $DAEMON --test > /dev/null \
			|| return 1
		start-stop-daemon --start --quiet --pidfile $PIDFILE \
			--exec $DAEMON -- $DAEMON_ARGS \
			|| return 2
	fi


}

#
# Function that stops the daemon/service
#
do_stop()
{
	start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile $PIDFILE --exec $DAEMON
	RETVAL="$?"
	[ "$RETVAL" = 2 ] && return 2

	# Wait for children to finish too if this is a daemon that forks
	# and if the daemon is only ever run from this initscript.
	# If the above conditions are not satisfied then add some other code
	# that waits for the process to drop all resources that could be
	# needed by services started subsequently.  A last resort is to
	# sleep for some time.
	start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec $DAEMON
	[ "$?" = 2 ] && return 2
	# Many daemons don't delete their pidfiles when they exit.
	rm -f $PIDFILE
	return "$RETVAL"
}

#
# Function that sends a SIGHUP to the daemon/service
#
do_reload() {
	#
	# If the daemon can reload its configuration without
	# restarting (for example, when it is sent a SIGHUP),
	# then implement that here.
	#
	start-stop-daemon --stop --signal 1 --quiet --pidfile $PIDFILE --exec $DAEMON
	return 0
}

case "$1" in
  start)
    [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC " "$NAME"
    do_start
    case "$?" in
		0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
		2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
	esac
  ;;
  stop)
	[ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
	do_stop
	case "$?" in
		0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
		2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
	esac
	;;
  status)
       status_of_proc "$DAEMON" "$NAME" && exit 0 || exit $?
       ;;
  #reload|force-reload)
	#
	# If do_reload() is not implemented then leave this commented out
	# and leave 'force-reload' as an alias for 'restart'.
	#
	#log_daemon_msg "Reloading $DESC" "$NAME"
	#do_reload
	#log_end_msg $?
	#;;
  restart|force-reload)
	#
	# If the "reload" option is implemented then remove the
	# 'force-reload' alias
	#
	log_daemon_msg "Restarting $DESC" "$NAME"
	do_stop
	case "$?" in
	  0|1)
		do_start
		case "$?" in
			0) log_end_msg 0 ;;
			1) log_end_msg 1 ;; # Old process is still running
			*) log_end_msg 1 ;; # Failed to start
		esac
		;;
	  *)
	  	# Failed to stop
		log_end_msg 1
		;;
	esac
	;;
  *)
	#echo "Usage: $SCRIPTNAME {start|stop|restart|reload|force-reload}" >&2
	echo "Usage: $SCRIPTNAME {start|stop|status|restart|force-reload}" >&2
	exit 3
	;;
esac

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