#!/bin/sh

# lh_losetup <device> <file> <partition>

DEVICE="${1}"
FILE="${2}"
PARTITION="${3}"

losetup "${DEVICE}" "${FILE}"
FDISK_OUT="`fdisk -l -u ${DEVICE} 2>&1`"
losetup -d "${DEVICE}"

LOOPDEVICE="`echo ${DEVICE}p${PARTITION:=1}`"
CYL="`echo ${FDISK_OUT} | sed -ne "s_^${LOOPDEVICE}[ *]*\([0-9]*\).*_\1_p" `"
#OFFSET="`expr 512 '*' ${CYL}`"
OFFSET="$((CYL*512))"

echo loop $DEVICE at offset $OFFSET

if [ "${PARTITION}" = "0" ]
then
	losetup "${DEVICE}" "${FILE}"
else
	losetup -o "${OFFSET}" "${DEVICE}" "${FILE}"
fi