#! /bin/sh
### BEGIN INIT INFO
# Provides:          cgroupfs-systemd
# Required-Start:    mountkernfs $local_fs
# Required-Stop:     
# Default-Start:     S
# Default-Stop:      0 6
# Should-Start:      cgroupfs-mount
# Short-Description: systemd cgroup filesystem
# Description:       Mount a named cgroup hierarchy 'systemd' so that Jessie
#                    systemd containers will work under this host.
### END INIT INFO

# Author: Christian Seiler <christian@iwakd.de>

# PATH should only include /usr/* if it runs after the mountnfs.sh script
PATH=/sbin:/usr/sbin:/bin:/usr/bin
DESC="systemd cgroup filesystem"
SCRIPTNAME=/etc/init.d/cgfs-systemd

# Load the VERBOSE setting and other rcS variables
. /lib/init/vars.sh

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.2-14) to ensure that this file is present
# and status_of_proc is working.
. /lib/lsb/init-functions

CGTMPFS=/sys/fs/cgroup
CGPATH=/sys/fs/cgroup/systemd
XATTR=",xattr"

# see http://stackoverflow.com/questions/4023830/bash-how-compare-two-strings-in-version-format
verlte() {
    [  "$1" = "`printf '%s\n%s\n' "$1" "$2" | sort -V | head -n1`" ]
    return $?
}

if ! verlte 3.7 "$(uname --kernel-release)" ; then
	# Kernel not new enough to support xattrs for cgroups,
	# mount anyway, and hope that the user knows what they're
	# doing.
	XATTR=""
fi

if [ -x /usr/bin/cgroupfs-mount ] ; then
	# cgroupfs-mount is installed from wheezy-backports, so maybe
	# the default path in /sys/fs/cgroup is actually used

	if grep -v '^#' /etc/fstab | grep -q cgroup; then
		# oh, but cgroup is active in /etc/fstab,
		# so cgroupfs-mount will just be a NO-OP,
		# so use other path
		CGTMPFS=
		CGPATH=/run/cgroup/systemd
	fi
else
	# either in /etc/fstab or something else, in either case
	# be conservative and mount the systemd hierarchy to
	# somewhere else...
	CGTMPFS=
	CGPATH=/run/cgroup/systemd
fi

[ -d /etc/default/cgfs-systemd ] && . /etc/default/cgfs-systemd

umask 022

do_start()
{
	if [ -n "$CGTMPFS" ] ; then
		mkdir -p "$CGTMPFS" || return 2
		if ! mountpoint -q "$CGTMPFS" ; then
			mount -t tmpfs none "$CGTMPFS"
		fi
	fi
	mkdir -p "$CGPATH" || return 2
	mount -t cgroup \
	      -o rw,none,name=systemd,nosuid,nodev,noexec,relatime$XATTR \
	      cgroup "$CGPATH" || return 2
}

do_stop()
{
	umount "$CGPATH" || :
	if mountpoint -q "$CGPATH" ; then
		return 2
	fi
	# try to remove, but don't care about errors here
	rmdir "$CGPATH" || :
	# ignore errors here, other hierarchies might be mounted
	if [ -n "$CGTMPFS" ] ; then
		umount "$CGTMPFS" || :
	fi
	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 $?
	;;
  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|status|restart|force-reload}" >&2
	exit 3
	;;
esac

: