#
# Start/Stop the workload manager
#
# Copyright IBM Corporation. 2008
#  
# Authors:     Balbir Singh <balbir@linux.vnet.ibm.com>
# This program is free software; you can redistribute it and/or modify it
# under the terms of version 2.1 of the GNU Lesser General Public License
# as published by the Free Software Foundation.
# 
# This program is distributed in the hope that it would be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#
#
# TODO: Make this code more robust, add error checking and recovery
# for invalid configuration or interrupted execution
#
# Make the script LSB compliant
#

CONF_FILE=/etc/wlm.conf
PROC_CGROUPS_FILE=/proc/cgroups
CGROUP_FS=cgroup
MOUNT_POINT=/dev/container
#MOUNT_OPTS=cpu
IGNORE_OPTS="ns cpuset"

parse_controller_file() {
	ctlr=$1
	file=$2
	tuid="root"
	tgid="root"
	cuid="root"
	cgid="root"

	pushd $PWD 2>&1 > /dev/null
	while read name opts
	do
		case $name in
		'mount')
			;;
		*)
			if ! echo $name | grep -q ^#
			then
				echo "Creating class $name"
				class=$name
				mkdir -p $MOUNTPOINT/$class
				cd $MOUNTPOINT/$class

				if echo $opts | grep -q "="
				then
					for single_opt in $opts
					do
						cf=`echo $single_opt | cut -d '=' -f1`
						co=`echo $single_opt | cut -d '=' -f2`
						case $cf in
						"tuid")
							tuid=$co
							;;
						"cuid")
							cuid=$co
							;;
						"tgid")
							tgid=$co
							;;
						"cgid")
							cgid=$co
							;;
						*)
							echo -n $co > $cf
							;;
						esac
					done
					chown -R $cuid:$cgid $MOUNTPOINT/$class
					chown -R $tuid:$tgid $MOUNTPOINT/$class/tasks
				fi
			fi
		esac
	done < $file
	popd 2>&1 > /dev/null
}

parse_controller_opts() {
	name=$1;
	file=$2;

	if [ ! -r $PROC_CGROUPS_FILE ]
	then
		echo "$PROC_CGROUPS_FILE does not exist, please compile"
		echo "cgroups into the kernel"
		exit 1
	else
		line=`grep -w $name $PROC_CGROUPS_FILE`
		if [ $? -ne 0 ]
		then
			echo "$name controller not enabled"
			exit 1
		fi

		active=`echo $line | awk '{print $2}'`
		if [[ $active -eq 0 ]]
		then
			echo "$name controller not mounted"
		else
			parse_controller_file $name $file
		fi
	fi
}

parse_conf_file() {
	while read name conf
	do
		# skip all comments
		if  ! echo $name | grep -q ^#
		then
			case $name in
			'mount')
				MOUNTPOINT=`echo $conf | cut -d ' ' -f1`;
				MOUNTOPTS=`echo $conf | cut -d ' ' -f2`;
				;;
			esac
		fi
	done < $CONF_FILE

	return 0;
}

mount_fs() {
	if [ ! -r $PROC_CGROUPS_FILE ]
	then
		echo "$PROC_CGROUPS_FILE does not exist, please compile"
		echo "cgroups into the kernel"
		exit 1
	else
		while read name hierarchy num_cgroups
		do
			if  ! echo $name | grep -q ^#
			then
				echo $IGNORE_OPTS | grep -wq $name
				if [[ $? -ne 0 ]]
				then
					MOUNT_OPTS=$name","$MOUNT_OPTS
				fi
			fi
		done < $PROC_CGROUPS_FILE
		MOUNT_OPTS=${MOUNT_OPTS%%","}
		#line=`grep -w $MOUNT_OPTS $PROC_CGROUPS_FILE`
		#if [ $? -ne 0 ]
		#then
		#	echo "$name controller not enabled"
		#	exit 1
		#fi
	fi
	mkdir -p $MOUNTPOINT
	mount -t $CGROUP_FS $CGROUP_FS -o $MOUNT_OPTS $MOUNTPOINT
	#
	# Give root tasks read/write permission to all, since tasks
	# tasks will be moved to root frequently
	#
	chmod ago+rwx $MOUNTPOINT/tasks
	chmod ago+rwx $MOUNTPOINT
	chmod +t      $MOUNTPOINT
	return $?
}

umount_fs() {
	umount $MOUNTPOINT
	rmdir $MOUNTPOINT
}
	
create_classes() {
	while read name conf
	do
		# skip all comments
		if  ! echo $name | grep -q ^#
		then
			case $name in
			'mount')
				;;
			*)
				parse_controller_opts $name $conf
			esac
		fi

	done < $CONF_FILE
}

start() {
	echo "Starting wlm service: "
	mount_fs
	if [ $? -eq 0 ]
	then
		create_classes
	fi
	[ $? == 0 ] && touch /var/lock/subsys/wlm
	return $?
}

move_all_to_init_class() {
	cd $MOUNTPOINT
	cat /proc/mounts | grep -wq $MOUNTPOINT
	if [ $? -ne 0 ]
	then
		echo "resource control filesystem not mounted"
		exit 1
	fi

	for i in `find . -type d`
	do
		case $i in
		'.')
			;;
		*)
			class=${i#./*}
			echo "Removing class $class"
			sed -nu p < ./$i/tasks > tasks
			rmdir $i
			;;
		esac
	done
	cd - > /dev/null
}


stop() {
	move_all_to_init_class
	umount_fs
}

trapped() {
	#
	# Do nothing
	#
	true
}

#
# main script work done here
#
trap "trapped ABRT" ABRT
trap "trapped QUIT" QUIT
trap "trapped TERM" TERM
trap "trapped INT"   INT

parse_conf_file

case $1 in
	'start')
		start;
		;;
	'stop')
		stop;
		;;
esac