#!/bin/bash
################################################################################
# Filename: grml2iso
# Purpose:  create a multiboot ISO using grml2usb
# Author:   Michael Prokop <mika@grml.org>,
#           Thorsten Glaser <tg@mirbsd.org>
################################################################################
# TODO:
# * generalise the script so we can provide it as part of the grml2usb suite
# * improve error handling
# * support isolinux as bootloader on the ISO
################################################################################

# define function getfilesize before "set -e"
if stat --help >/dev/null 2>&1; then
	getfilesize='stat -c %s'	# GNU stat
else
	getfilesize='stat -f %z'	# BSD stat
fi

usage() {
  echo >&2 "Usage: $0 target.iso source1.iso [source2.iso ...]"
  exit 1
}

set -e
set -u

# ********* PLEASE ADJUST! *******************************************
# specify path to the grml2usb script you'd like to use
GRML2USB='grml2usb'
# work directory for creating the filesystem
WRKDIR='/dev/shm/grml2iso.tmp'
# ********* PLEASE ADJUST! *******************************************

test $# -lt 2 && usage
if test -e "$1"; then
  echo >&2 Error: target file "'$1'" already exists.
  usage
fi
ISOFILE=$1; shift

# variables
  ORIG_DIR="$(pwd)"
  # note: grub-pc_1.96+20090603-1_i386.deb seems to be b0rken
  GRUB_DEB="grub-pc_1.96+20080724-16_i386.deb"

# normalise path (in mksh I’d just use the realpath builtin…)
case $ISOFILE in
/*) ;;
*) ISOFILE=$ORIG_DIR/$ISOFILE ;;
esac

# create necessary stuff under WRKDIR
  rm -rf "$WRKDIR/cddir" "$WRKDIR/grub_tmp"
  mkdir -p "$WRKDIR/cddir" "$WRKDIR/grub_tmp"

# execute grml2usb with all ISOs you'd like to install
  $GRML2USB "$@" "$WRKDIR/cddir"

# install grub2 files
# as we don't want to rely on a grub2 installation on the
# running system let's grab it from the net
  cd "$WRKDIR"/grub_tmp/
  wget http://ftp.de.debian.org/debian/pool/main/g/grub2/"$GRUB_DEB"
  ar x "$GRUB_DEB"
  tar xzf data.tar.gz
  ./usr/bin/grub-mkimage -d usr/lib/grub/i386-pc \
    -o "$WRKDIR"/cddir/boot/grub/core.img biosdisk iso9660

  for a in usr/lib/grub/i386-pc/{*.mod,efiemu??.o,command.lst,moddep.lst,fs.lst,handler.lst,parttool.lst}; do
    test -e $a && cp $a "$WRKDIR"/cddir/boot/grub/
  done

  cat usr/lib/grub/i386-pc/cdboot.img "$WRKDIR"/cddir/boot/grub/core.img \
    > "$WRKDIR"/cddir/boot/grub/eltorito.img
  cd "$WRKDIR/cddir"

# finally generate the CD/DVD-iso
  mkisofs -V 'grml-multiboot' -l -r -J -no-pad \
    -no-emul-boot -boot-load-size 4 -boot-info-table \
    -b boot/grub/eltorito.img -c boot/grub/eltorito.cat \
    -o "$ISOFILE" .

# pad the output ISO to multiples of 256 KiB for partition table support
  siz=$($getfilesize "$ISOFILE")
  cyls=$(echo "$siz / 512 / 32 / 16 + 1" | bc)	# C=$cyls H=16 S=32
  ofs=$(echo "$cyls * 16 * 32 * 512 - 1" | bc)	# padding offset (size - 1)
  dd if=/dev/zero bs=1 count=1 seek=$ofs of="$ISOFILE" 2>/dev/null

# create a manifold-boot image with a partition table, if possible
  if mksh -c true 2>/dev/null && \
    test -e /usr/share/grml-live/scripts/bootgrub.mksh; then
      echo "Creating a manifold-boot ISO image"
      echo 1 63 | \
        mksh /usr/share/grml-live/scripts/bootgrub.mksh -A -M 1 -p 0x83 -g $cyls:16:32 | \
        cat - boot/grub/core.img | \
        dd conv=notrunc of="$ISOFILE" conv=notrunc 2>/dev/null
  else
      echo "Cannot find mksh or bootgrub.mksh, not generating manifold-boot ISO image"
  fi

# cleanup
  cd "$ORIG_DIR"
  sync
  rm -rf "$WRKDIR/cddir" "$WRKDIR/grub_tmp"

# we are done :)
  echo "Generated $ISOFILE"

## EOF #########################################################################