#! /bin/bash
#
# usbboot
#
# Author: Michael Towers <gradgrind[at]online[dot]de>
#
# This file is part of the larch project.
#
#    larch 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.
#
#    larch 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 larch; if not, write to the Free Software Foundation, Inc.,
#    51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#
#----------------------------------------------------------------------------
# 2008.06.22

APP="$( basename $0 )"

usage () {
    echo
    echo "Usage:"
    echo "  ${APP} [<Arch installation root directory>]"
    echo
    echo "   Prepare a bootable USB-stick from a larch build."
    echo "   If no Arch directory is given, '/' is assumed."
    exit 1
}

if [ -n "$1" ]; then
    AINSTALL="$( readlink -f $1 )"
else
    AINSTALL=""
fi
CDDATA=${AINSTALL}/.larch/cd

if [ ! -f ${CDDATA}/system.sqf ]; then
    echo "ERROR: ${CDDATA} does not contain larch cd data"
    usage
fi
if [ ! -f ${CDDATA}/isolinux/isolinux.cfg ]; then
    echo "ERROR: isolinux data not in ${CDDATA}/isolinux"
    exit 1
fi

if ! [ -f ${AINSTALL}/usr/bin/syslinux ]; then
    echo "ERROR: syslinux not found -"
    echo "      it must be installed on live system"
    return 1
fi

echo "//"
echo "// **********************************************************"
echo "//"
echo "// ${APP} will prepare a bootable USB stick with your"
echo "// previously prepared larch data from ${CDDATA}"
echo "//"
echo "// Please insert your USB stick, which should already be"
echo "// appropriately partitioned."
echo "//"
echo "// **********************************************************"
echo "//"

# test if the script is started by root user. If not, exit
if [ $UID -ne 0 ]; then
    echo "Only root can run ${APP}"; exit 1
fi

echo "// Do you want to continue?"
# Await yes or no
read -p "// [y/N]: " ans
if [ -z "`echo ${ans} | grep '^ *[yY]'`" ]; then exit 2; fi

echo "//"
echo "// Enter the number of the partition you wish to use (0 to quit):"

devices=/tmp/devices$$
:> ${devices}
i=0
sfdisk -d | grep "/dev/sd[a-z][1-4] " | grep -v "Id= [05]" | \
        sed "s|\(.*\):.*size=\( *[0-9]*\).*|\1 \2|" | while read device sectors; do

    i=$(( ${i} + 1 ))
    echo "${device}" >>${devices}
    echo "// ${i}: ${device} $(( ${sectors} / 2048 )) MiB"
done

while true; do
    read -p "// Device: " d
    if [ "${d}" -eq "0" ]; then exit 1; fi
    i=0
    { while read device; do
        i=$(( ${i} + 1 ))
        if [ "${d}" -eq "${i}" ]; then break 2; fi
    done } <${devices}
done

rm ${devices}

echo "//"
read -p "// \"${device}\" will now be prepared. Continue? [y/N]: " ans
if [ -z "`echo ${ans} | grep '^ *[yY]'`" ]; then exit 1; fi

echo "//"
echo "// Formatting ${device} (vfat)"
dev=${device:0:8}
part=${device:8}
sfdisk ${dev} -N${part} <<EOF
,,0e,*
EOF

dd if=/dev/zero of=${device} bs=512 count=1
mkfs.vfat ${device}

echo "// Copying the boot sector"
dd if=${AINSTALL}/usr/lib/syslinux/mbr.bin of=${dev}

echo "// Copying the files"
stick=/tmp/mnt
mkdir -p ${stick}
umount ${device} &>/dev/null
mount ${device} ${stick}
if [ $? != 0 ]; then
  echo "ERROR: Failed to mount device, quitting"
  exit 3
fi
cp -a ${CDDATA}/* ${stick}
mv ${stick}/isolinux ${stick}/syslinux
mv ${stick}/syslinux/isolinux.cfg ${stick}/syslinux/syslinux.cfg
rm -f ${stick}/syslinux/isolinux*

umount ${stick}

echo "// Running syslinux"
if [ -n "${AINSTALL}" ]; then
    mount --bind /dev ${AINSTALL}/dev
    mount --bind /proc ${AINSTALL}/proc
    chroot ${AINSTALL} syslinux ${device}
    umount ${AINSTALL}/dev
    umount ${AINSTALL}/proc
else
    syslinux ${device}
fi

echo "//"
echo "// Done!"
echo "// If all went well your usb stick should now be a bootable larch system"