#!/bin/sh
#
#       Shared Disk File EXclusiveness (SF-EX) OCF RA. 
#       prevent a destruction of data on shared disk file system 
#	due to Split-Brain.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  
# 02110-1301, USA.
#
# Copyright (c) 2007 NIPPON TELEGRAPH AND TELEPHONE CORPORATION
#
# NOTE:
#	As a prerequisite for running SF-EX, one device should be
#	initialized as below.
#
#		sfex_init [-n <numlocks>] <device>
#
#	Example:
#
#		/usr/sbin/sfex_init -n 10 /dev/sdb1
#
#	if further information is necessary, See README.
#
#######################################################################
# Initialization:

# switching ocf-shellfuncs path
: ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/resource.d/heartbeat}
. ${OCF_FUNCTIONS_DIR}/.ocf-shellfuncs

unset LC_ALL; export LC_ALL
unset LANGUAGE; export LANGUAGE

#######################################################################

SFEX_DAEMON=${HA_BIN}/sfex_daemon

usage() {
    cat <<END
    usage: $0 {start|stop|monitor|meta-data}
END
}

meta_data() {
    cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="sfex">
<version>1.3</version>

<longdesc lang="en">
Resource script for SF-EX. It manages a shared storage medium exclusively .
</longdesc>
<shortdesc lang="en">Manages exclusive access to shared storage using Shared Disk File EXclusiveness (SF-EX)</shortdesc>
<parameters>
<parameter name="device" unique="0" required="1">
<longdesc lang="en">
Block device path that stores exclusive control data.
</longdesc>
<shortdesc lang="en">block device</shortdesc>
<content type="string" default="" />
</parameter>
<parameter name="index" unique="0" required="0">
<longdesc lang="en">
Location in block device where exclusive control data is stored. 1 or more is specified. Default is 1.
</longdesc>
<shortdesc lang="en">index</shortdesc>
<content type="integer" default="1" />
</parameter>
<parameter name="collision_timeout" unique="0" required="0">
<longdesc lang="en">
Waiting time when a collision of lock acquisition is detected. Default is 1 second.
</longdesc>
<shortdesc lang="en">waiting time for lock acquisition</shortdesc>
<content type="integer" default="1" />
</parameter>
<parameter name="monitor_interval" unique="0" required="0">
<longdesc lang="en">
Monitor interval(sec). Default is 10 seconds
</longdesc>
<shortdesc lang="en">monitor interval</shortdesc>
<content type="integer" default="10" />
</parameter>
<parameter name="lock_timeout" unique="0" required="0">
<longdesc lang="en">
Valid term of lock(sec). Default is 20 seconds.
</longdesc>
<shortdesc lang="en">Valid term of lock</shortdesc>
<content type="integer" default="20" />
</parameter>
</parameters>

<actions>
<action name="start" timeout="600" />
<action name="stop" timeout="20s" />
<action name="monitor" depth="0" timeout="10" interval="10" />
<action name="meta-data" timeout="5" />
</actions>
</resource-agent>
END
}

#
# START: Exclusive control starts.
#
# It loops permanently until the lock can be acquired when locked with 
# the other node. In this case, the reception of the stop signal by the 
# timeout time passage set to CIB becomes the only stop opportunity. 
#
sfex_start() {
	ocf_log info "sfex_daemon: starting..."

	sfex_monitor
	if [ $? -eq $OCF_SUCCESS ]; then
		ocf_log info "sfex_daemon already started."
		return $OCF_SUCCESS
	fi

	$SFEX_DAEMON -i $INDEX -c $COLLISION_TIMEOUT -t $LOCK_TIMEOUT -m $MONITOR_INTERVAL -r ${OCF_RESOURCE_INSTANCE} $DEVICE

	rc=$?
	if [ $rc -ne 0 ]; then
		ocf_log err "sfex_daemon failed to start."
		return $OCF_ERR_GENERIC
	fi
	
	sleep 2
	sfex_monitor
	if [ $? -eq $OCF_SUCCESS ]; then
		ocf_log info "sfex_daemon: started."
		return $OCF_SUCCESS
	fi
	ocf_log err "Can't find a sfex_daemon process. Starting a sfex_daemon failed."
	return $OCF_ERR_GENERIC
}

#
# STOP: stop exclusive control 
#
sfex_stop() {
	ocf_log info "sfex_daemon: stopping..."

	# Check the sfex daemon has already stopped.
	sfex_monitor
	if [ $? -eq $OCF_NOT_RUNNING ]; then
		ocf_log info "sfex_daemon already stopped."
		return $OCF_SUCCESS
	fi

	# Stop sfex daemon by sending SIGTERM signal.
	pid=`/usr/bin/pgrep -f "$SFEX_DAEMON .* ${OCF_RESOURCE_INSTANCE} "`
	/bin/kill $pid
	rc=$?
	if [ $rc -ne 0 ]; then
		ocf_log err "sfex_daemon failed to stop"
		return $rc
	fi

#sfex could be in state D if the device is gone, and then not terminate.	
#Wait and check again if the daemon is already properly shutdown.

	sleep 4
	sfex_monitor
	rc=$?
	if [ $rc -ne $OCF_NOT_RUNNING ]; then
		ocf_log err "sfex_daemon failed to stop"
		return $rc
	fi
	ocf_log info "sfex_daemon: stopped."
	return $OCF_SUCCESS
}

sfex_monitor() {
	ocf_log debug "sfex_monitor: started..."

	# Find a sfex_daemon process using daemon name and resource name.
	if /usr/bin/pgrep -f "$SFEX_DAEMON .* ${OCF_RESOURCE_INSTANCE} " > /dev/null 2>&1; then
		ocf_log debug "sfex_monitor: complete. sfex_daemon is running."
		return $OCF_SUCCESS
	fi

	ocf_log debug "sfex_monitor: complete. sfex_daemon is not running."
	return $OCF_NOT_RUNNING
}

#
# main process 
#

# check arguments
if [ $# -ne 1 ]; then
	usage
	exit $OCF_ERR_ARGS
fi
OP=$1

# These operations do not require instance parameters
case $OP in
	meta-data)
		meta_data
		exit $OCF_SUCCESS
		;;
	usage)
		usage
		exit $OCF_SUCCESS
		;;
esac

# check parameters
DEVICE=$OCF_RESKEY_device
INDEX=${OCF_RESKEY_index:-1}
COLLISION_TIMEOUT=${OCF_RESKEY_collision_timeout:-1}
LOCK_TIMEOUT=${OCF_RESKEY_lock_timeout:-20}
MONITOR_INTERVAL=${OCF_RESKEY_monitor_interval:-10}

sfex_validate () {
if [ -z "$DEVICE" ]; then
	ocf_log err "Please set OCF_RESKEY_device to device for sfex meta-data"
	exit $OCF_ERR_ARGS
fi
if [ ! -w "$DEVICE" ]; then
	ocf_log warn "Couldn't find device [$DEVICE]. Expected /dev/??? to exist"
	exit $OCF_ERR_ARGS
fi
}

if [ -n "$OCF_RESKEY_CRM_meta_clone" ]; then
	ocf_log err "THIS RA DO NOT SUPPORT CLONE MODE!"
	exit $OCF_ERR_CONFIGURED
fi

case $OP in
	start)
		sfex_start
		;;
	stop)
		sfex_stop
		;;
	monitor)
		sfex_monitor
		;;
	validate-all)
		sfex_validate
		;;
	*)
		exit $OCF_ERR_UNIMPLEMENTED
		;;
esac
exit $?