#!/bin/sh
DATABASE=/dev/.bdev

mk_dev() {
	NAME=$1-${2/\//-}
	(
		/sbin/dmsetup -v create $NAME || \
		/sbin/dmsetup remove $NAME &> /dev/null
	) | \
	sed -e '/minor:/!d;s/^[^0-9]*\([0-9]*\),[^0-9]*\([0-9]*\).*$/\1:\2/'
}

rm_dev() {
	NAME=$1-${2/\//-}
	/sbin/dmsetup remove $NAME &> /dev/null
}

mk_nod() {
	/bin/mknod /dev/$1 b ${2%:[0-9]*} ${2#[0-9]*:}
} 

rm_nod() {
	rm -f /dev/$1
}

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

mk_part() {
	echo part $1 $2 $3 $4 >> /tmp/log
	NDEV=$(echo "0 $3 linear $4 $2" | mk_dev part $1 $4)
	if [ -z "$NDEV" ]; then
		return 1
	fi
	OF=$DATABASE/of/$5
	TO=$DATABASE/to/$NDEV
	echo TYPE=part > $TO
	echo NAME=$1 >> $TO
	echo "LIST=\"\$LIST $NDEV\"" >> $OF
}

get_parts() {
	/sbin/sfdisk -dfqL /dev/$1 2> /dev/null | \
	sed -s '/start=/!d;s/[=,]/ /g;s/^\/dev\/tmp-//' | \
	awk '{ print $1 " " $4 " " $6 }'
}

check_parts() {
	get_parts $4 | \
	while read PART START SIZE; do
		if [ "$SIZE" -gt 0 ]; then
			mk_part $PART $START $SIZE $3 $2
		fi
	done
}

rm_part() {
	rm_dev part $1
}

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

register_dev() {
	echo register $1 $2 >> /tmp/log
	echo DEV=$2 > $DATABASE/of/$1
}

unregister_dev() {
	echo unregister $1 $2 >> /tmp/log
	rm -f $DATABASE/of/$1
}

add_dev() {
	if [ -f $DATABASE/to/$2 ]; then
		source $DATABASE/to/$2
	else
		NAME=$1
		RET=1
	fi
	echo add "$NAME $2" >> /tmp/log
	TMP=tmp-$NAME
	mk_nod $TMP $2
	check_parts $1 $NAME $2 $TMP
	rm_nod $TMP
}

notify_dev() {
	echo notify $TYPE $1 $2 >> /tmp/log
	case $TYPE in
	    part)
		rm_part $1 $2
		;;
	esac
}

remove_dev() {
	if [ -f $DATABASE/to/$2 ]; then
		source $DATABASE/to/$2
		rm -f $DATABASE/to/$2
	else
		NAME=$1
		RET=1
	fi
	echo remove $NAME $2 >> /tmp/log
	for i in $LIST; do
		if [ -e $DATABASE/to/$i ]; then
			source $DATABASE/to/$i
			notify_dev $NAME $i
		fi
	done
}

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

if [ ${DEVPATH} == ${DEVPATH#/block} ]; then
	exit 1
fi

if [ -n "$2" ]; then
	ACTION=add
	KERNEL=$1
	DEV=$2
	if [ ! -f /sys/block/$KERNEL/dev ]; then
		exit 0
	fi
else
	if [ "$ACTION" != remove ]; then
		exit 0
	fi
	KERNEL=${DEVPATH##*/}
fi

dotlockfile -r3 -p $DATABASE/lock || exit 1

RET=0
NAME=""

echo action $ACTION >> /tmp/log
case "$ACTION" in
    add)
	if [ ! -f $DATABASE/uptodate ]; then
		rm -Rf $DATABASE/of $DATABASE/to
		mkdir -p $DATABASE/of $DATABASE/to
		for i in /sys/block/*; do
			register_dev ${i#/sys/block/} $(<$i/dev)
		done
		touch $DATABASE/uptodate
		if [ -e $DATABASE/of/$KERNEL ]; then
			add_dev $KERNEL $DEV
		fi
	else
		if [ ! -e $DATABASE/of/$KERNEL ]; then
			register_dev $KERNEL $DEV
			if [ -e $DATABASE/of/$KERNEL ]; then
				add_dev $KERNEL $DEV
			fi
		fi
	fi

	;;
    remove)
	if [ -e $DATABASE/of/$KERNEL ]; then
		LIST=""
		source $DATABASE/of/$KERNEL
		remove_dev $KERNEL $DEV
		unregister_dev $KERNEL $DEV
	fi
	;;
esac
	
dotlockfile -u $DATABASE/lock
if [ $RET -gt 0 ]; then
	exit 1
else
	if [ -n "$NAME" ]; then
		echo result $NAME >> /tmp/log
		case $ACTION in
		    add)
			mk_nod $NAME $DEV
			;;
		    remove)
			rm_nod $NAME
		esac
	else
		echo ignore >> /tmp/log
	fi
	exit 0
fi