#!/bin/sh
#
# This file remasters an existing ISO image by simply appending kernel
# parameters to its syslinux .cfg files. This can be used e.g. to append
# speakup.synth=foobar
#
# This script depends on
# coreutils findutils sed bsdtar genisoimage
#
# Copyright (c) Samuel Thibault
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. Neither the name of the University nor the names of its contributors
#    may be used to endorse or promote products derived from this software
#    without specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
set -e

if [ "$#" -lt 3 ]
then
	echo "usage: $0 [options...] \"kernel_option1 kernel_option2\" input.iso output.iso"
	echo "Remasters input.iso into output.iso, simply appending kernel parameters to its"
	echo "syslinux .cfg files."
	echo
	echo "Available options:"
	echo "    -mount	mount image instead of using bsdtar to extract it"
	echo "		(needs sudo)"
	echo "    -gtk		set graphical installer by default"
	exit 1
fi

mount=0
gtk=0
while true
do
	case $1 in
	-mount)
		mount=1
		shift
		;;
	-gtk)
		gtk=1
		shift
		;;
	*)
		break
		;;
	esac
done

options="$1"
input="$2"
output="$3"

dir="`mktemp -d`"
if [ "$mount" == 1 ]
then
	dirmount="`mktemp -d`"
	sudo mount "$input" "$dirmount" -o loop
	cp -a -T "$dirmount" "$dir"
	sudo umount "$dirmount"
	rmdir "$dirmount"
else
	cat "$input" | bsdtar -C "$dir" -x -f -
fi

chmod -R +w "$dir"
find "$dir"/isolinux -name \*.cfg | xargs sed -i -e "s/\\(append .*\\)\\( *\)$/\\1 $options\\2/"
[ "$gtk" == 1 ] && rm -f "$dir"/isolinux/txt.cfg "$dir"/isolinux/amdtxt.cfg
genisoimage -r -J -b isolinux/isolinux.bin -c isolinux/boot.cat \
	-no-emul-boot -boot-load-size 4 -boot-info-table \
	-o "$output" "$dir"

rm -fr "$dir"