#!/bin/bash

host_id=0
cmd=""
vgname=""
lvname=""
lock_mode=""
active_mode=""
offset=""

help() {
	vg="\$vg"
	host_id="\$host_id"
	echo ""
	echo "1. /etc/sanlvm.conf"
	echo "   must contain unique host_id definition from 1 to 2000, e.g."
	echo "   host_id 1"
	echo ""
	echo "2. sanlvm vgcreate [options] $vg <devs>"
	echo "   create vg, unprotected by sanlock,"
	echo "   create and initialize storage in $vg for sanlock to use"
	echo "   vgcreate [options] $vg <devs>"
	echo "   lvcreate -n leases -L 1G $vg"
	echo "   sanlock direct init -s $vg:0:/dev/$vg/leases:0"
	echo "   sanlock direct init -r $vg:vglk:/dev/$vg/leases:1048576"
	echo "   vgchange --addtag @sanlvm $vg"
	echo ""
	echo "3. sanlvm start"
	echo "   start lockspaces for vgs @sanlvm, created above"
	echo "   sanlock add_lockspace -s $vg:$host_id:/dev/$vg/leases:0"
	echo ""
	echo "4. sanlvm <lvmcmd> ..."
	echo "   lvm commands within $vg are serialized by sanlock"
	echo "   sanlock command -r $vg:vglk:/dev/$vg/leases:1048576 -c /sbin/lvm <lvmcmd> ..."
	echo ""
	exit 0
}

if [[ $# == 0 ]]; then
	help
fi

arg1=$1

if [[ $arg1 == "help" ]]; then
	help
fi

if [[ $arg1 == "--ex" ]] || [[ $arg1 == "--sh" ]]; then
	lock_mode=$arg1
	cmd=$2
else
	cmd=$1
fi

# vg name is the arg preceding the first pv path arg,
# or the last arg when no pv paths exist
# e.g. vgcreate, vgchange, vgextend, lvcreate

get_vg_name() {
	prev=$2

	for i in $args
	do 
		first=`expr substr $i 1 1`
		if [ "$first" == "/" ]; then
			vgname=$prev
			return
		fi

		prev=$i
	done

	for i in $args
	do 
		vgname=$i
	done
}

# lv name follows -n or --name arg
# FIXME: this doesn't work without a space, i.e. -nfoo

get_lv_name() {
	save_next=0

	for i in $args
	do 
		if [[ $save_next == 1 ]]
			lvname=$i
			return
		fi

		if [[ "$i" == "-n" ]] || [[ "$i" == "--name" ]]; then
			save_next=1
			continue
		fi
	done
}

# vg name is part of an lv path, e.g. lvextend, lvremove
# first arg containing '/'

get_vg_lv_name() {
	for i in $args
	do 
		ind=`expr index $i /`
		if [ "$ind" -gt 0 ]; then
			lvname=`basename $i`
			dir=`dirname $i`
			vgname=`basename $dir`
			return
		fi
	done
}

get_host_id() {
	host_id=`awk '/^host_id/ { print $2 }' < /etc/sanlvm.conf`

	if [[ $? -ne 0 ]]; then
		echo no host_id found in /etc/sanlvm.conf
		exit 1
	fi
}

# search lvchange args for -a, ---available
# if there's a "y" anywhere after the option, then active_mode="y"
# if there's a "n" anywhere after the option, then active_mode="n"

get_active_mode() {
	for i in $args
	do 
		if [[ "$i" == "-ay" ]] || [[ "$i" == "-aly" ]] || [[ "$i" == "-aey" ]]; then
			active_mode="y"
			return
		fi

		if [[ "$i" == "-an" ]] || [[ "$i" == "-aln" ]] || [[ "$i" == "-aen" ]]; then
			active_mode="n"
			return
		fi

		if [[ "$i" == "-a" ]] || [[ "$i == "--available" ]]; then
			check_next=1
			continue
		fi

		if [[ $check_next == 1 ]]; then
			ind=`expr index $i y`
			if [ "$ind" -gt 0 ]; then
				active_mode="y"
			else
				active_mode="n"
			fi
			return
		fi
	done
}

# get the offset value from the @sanlvm_offset_xyz tag on the lv

get_lease_offset() {
	tags=`lvs --noheadings -o lv_name,lv_tags $vgname | grep $lvname | awk '{print $2}'`

	# FIXME: handle case where the lv has tags other than ours

	offset=`echo $tags | cut --delimiter=_ --fields=3`
}

if [[ "$cmd" == "start" ]]; then
	get_host_id

	for vgname in `vgs @sanlvm --noheadings -o vg_name`; do
		lvm lvchange -a y /dev/$vgname/leases
		echo adding lockspace $vgname, this may take minutes...
		sanlock add_lockspace -s $vgname:$host_id:/dev/$vgname/leases:0
	done

	exit 0
fi

if [[ "$cmd" == "vgcreate" ]]; then
	args=$*

	get_vg_name

	lvm "$@"

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	lvm lvcreate -n leases -L 1G $vgname

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	sanlock direct init -s $vgname:0:/dev/$vgname/leases:0

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	sanlock direct init -r $vgname:vglk:/dev/$vgname/leases:1048576

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	lvm vgchange --addtag @sanlvm $vgname

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	exit 0

elif [[ "$cmd" == "_lvcreate" ]]; then
	# wrapped by vglk

	shift

	args=$*

	get_vg_name
	get_lv_name

	# FIXME: get offset by searching leases lv for unused lease area
	offset=2097152

	# FIXME: add arg to disable activation
	# lvcreate
	lvm "$@"

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	# FIXME: can remove this once lvcreate doesn't activate
	lvm lvchange -an $vgname/$lvname

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	lvm lvchange --addtag @sanlvm_offset_$offset $vgname/$lvname

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	sanlock direct init -r $vgname:$lvname:/dev/$vgname/leases:$offset

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	exit 0

elif [[ "$cmd" == "lvcreate" ]]; then
	# we need the multiple steps in _lvcreate to all be wrapped in vglk

	args=$*

	get_vg_name

	sanlock command -r $vgname:vglk:/dev/$vgname/leases:1048576 -c ./sanlvm _lvcreate "$@"

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	exit 0

elif [[ "$cmd" == "_lvremove" ]]; then
	# wrapped by vglk

	shift

	args=$*

	get_vg_lv_name
	get_lease_offset

	# lvremove, this will fail if the lv is in use
	lvm "$@"

	# FIXME: release lv lease is there is one

	# FIXME: clear the lease area that was used for the lv activation
	# lease, if there was one (there was an offset tag)

	exit 0

elif [[ "$cmd" == "lvremove" ]]; then
	# we need the multiple steps in _lvremove to all be wrapped in vglk

	args=$*

	get_vg_lv_name

	sanlock command -r $vgname:vglk:/dev/$vgname/leases:1048576 -c ./sanlvm _lvremove "$@"

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	exit 0


elif [[ "$cmd" == "lvchange" ]]; then
	# sanlvmd is a process that sanlock views as owning the lv
	# activation leases.  sanlvmd should restrict sigkill, and
	# on sigterm from sanlock, it should try to forcibly deactivate
	# the sanlvm lvs, or suspend the lv's or suspend lv's, replace
	# with the error target and resume.
	# (what about handling different vg lockspaces separately?)

	args=$*

	get_vg_lv_name
	get_active_mode
	get_lease_offset

	if [[ "$active_mode" == "y" ]]; then
		# acquire lease, then activate

		if [[ "$lock_mode" == "--sh" ]]; then
			suffix=":SH"
		elif [[ "$lock_mode" == "--ex" ]]; then
			suffix=""
		else
			echo "use sanlvm --ex|sh for lv activation"
			exit 1
		fi

		sanlock client acquire -r $vgname:$lvname:/dev/$vgname/leases:$offset$suffix -p `pidof sanlvmd`

		# lvchange activate
		lvm "$@"

	elif [[ "$active_mode" == "n" ]]; then
		# deactivate, then release lease

		# lvchange deactivate
		lvm "$@"

		sanlock client release -r $vgname:$lvname:/dev/$vgname/leases:$offset -p `pidof sanlvmd`
	else
		# non-activation related change to lv
		# FIXME: do we also want to take ex lv lease?
		sanlock command -r $vgname:vglk:/dev/$vgname/leases:1048576 -c /sbin/lvm "$@
	fi

	exit 0

elif [[ "$cmd" == "lvextend" ]] || [[ "$cmd" == "lvreduce" ]]; then
	args=$*

	get_vg_lv_name

	# FIXME: do we also want to take ex lv lease?

	sanlock command -r $vgname:vglk:/dev/$vgname/leases:1048576 -c /sbin/lvm "$@"

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	exit 0

else
	if [[ $# -lt 2 ]]; then
		echo vg name required
		exit 1
	fi

	args=$*

	get_vg_name

	sanlock command -r $vgname:vglk:/dev/$vgname/leases:1048576 -c /sbin/lvm "$@"

	if [[ $? -ne 0 ]]; then
		exit 1
	fi

	exit 0
fi