#!/bin/bash
#
# larch-grub-install - Set up a grub boot
#
#2010.08.09

# $1: path to system to be used as chroot for running grub
#          ("/" if no chroot is to be used)
# $2: larch partition, e.g. /dev/sdb1
# $3: 'MBR', if to be installed to MBR

INSTLDIR="$1"
if [ "${INSTLDIR}" = "/" ]; then
    INSTLDIR=""
fi
DEVICE="$2"
mbr="$3"

dev=${DEVICE:0:8}
part=${DEVICE:8}

# Convert the device and partion to grub syntax
grubdevice ()
{
    ## The contents of DEVICE.map look something like this:
    #(fd0)   /dev/fd0
    #(hd0)   /dev/hda
    #(hd1)   /dev/sda
    gdev="$( cat ${INSTLDIR}${dmap} | grep "${dev}" | cut -f1  | tr -d "()" )"
    gpart=$(( ${part} - 1 ))
    gdst="${gdev},${gpart}"
    [[ ${mbr} != 'MBR' ]] && gdev=${gdst}
    echo "#Installing GRUB to (${gdev}), root (${gst})"
}

dmap=/tmp/DEVICE.map
rm -f ${INSTLDIR}${dmap}
if [ -n "${INSTLDIR}" ]; then
    # First try to get a device mapping
    mount --bind /dev ${INSTLDIR}/dev
    echo "quit" | chroot ${INSTLDIR} grub --no-floppy --device-map=${dmap} --batch
    grubdevice
    # Now actually install grub
    # As far as I can tell, the extra options to grub are not needed here
    chroot ${INSTLDIR} grub --batch <<EOT
root (${gdst})
setup (${gdev})
quit
EOT
    umount ${INSTLDIR}/dev
else
    # First try to get a device mapping
    echo "quit" | grub --no-floppy --device-map=${dmap} --batch
    grubdevice
    # Now actually install grub
    # As far as I can tell, the extra options to grub are not needed here
    grub --batch <<EOT
root (${gdst})
setup (${gdev})
quit
EOT
fi
rm -f ${INSTLDIR}${dmap}