#!/bin/sh
#
# «oem-config-remaster» - Remaster an Ubuntu ISO with an additional repository
# and preseed data for oem-config.
#
# Copyright (C) 2010 Canonical Ltd.
#
# Authors:
#
# - Evan Dandrea <ev@ubuntu.com>
#
# This program 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 3 of the License, or (at your option) any later
# version.
#
# This program 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
# this program.  If not, see <http://www.gnu.org/licenses/>.

set -e

if ! [ -w / ]; then
	echo "This program must be run as root."
	exit 1
fi
cleanup() {
	echo "Cleaning up."
	set +e
	if [ -n "$cd_writable" ]; then
		(umount $cd_writable && rm -rf $cd_backing $cd_writable) || \
		rmdir $cd_writable $cd_backing
	fi
	if [ -n "$writable" ]; then
		(umount $writable && rm -rf $backing $writable) || \
		rmdir $writable $backing
	fi
	if [ -n "$squash" ]; then
		(umount $squash && rm -rf $squash) || \
		rmdir $squash
	fi
	if [ -n "$iso" ]; then
		(umount $iso && rm -rf $iso) || \
		rmdir $iso
	fi
	echo "All done."
}
usage() {
	echo "Usage: $0 [-i gpg-key-id] [-t cd-title] [-o output-file] [-r extra-repository] [-e early-command] [-l late-command] cd-image packages"
}
set -- $(getopt i:t:o:r:e: "$@")
if [ $# -lt 2 ]; then
	usage
fi
# TODO: Support passing an argument for packages to explicitly not include
# (with the assumption being that they'll be downloaded from the network in
# oem-config).
while [ $# -gt 0 ]; do
	case "$1" in
		-i)	KEY_ID="$2"; shift;;
		-t)	CD_TITLE="$2"; shift;;
		-o)	CD_FILE="$2"; shift;;
		-r)	REPO="$2"; shift;;
		-e)	EARLY="$2"; shift;;
		-l)	LATE="$2"; shift;;
		--)	shift; break;;
		-*)	usage;;
		*)	break;;
	esac
	shift
done
trap cleanup EXIT HUP INT QUIT TERM
image="$1"
pkgs="$2"

iso=$(mktemp -d)
mount -o loop $image $iso
s="$iso/casper/filesystem.squashfs"
if ! [ -e "$s" ]; then
	echo "Could not find the squashfs at '$s'."
	umount $iso || true
	exit 1
fi
cd_backing=$(mktemp -d)
cd_writable=$(mktemp -d)
mount -t aufs -o br=$cd_backing:$iso none $cd_writable

squash=$(mktemp -d)
mount -o loop $s $squash
backing=$(mktemp -d)
writable=$(mktemp -d)
mount -t aufs -o br=$backing:$squash none $writable

# TODO: Support additional sources.
sed -i 's/main /main universe multiverse /g' $writable/etc/apt/sources.list
cp /etc/resolv.conf $writable/etc
chroot $writable apt-get update #|| true
chroot $writable apt-get -d -y install $pkgs
mkdir $cd_writable/extra
find $writable/var/cache/apt/archives -name "*.deb" -exec cp {} $cd_writable/extra \;
apt-ftparchive packages $cd_writable/extra >$cd_writable/extra/Packages
apt-ftparchive release $cd_writable/extra >$cd_writable/extra/Release
gpg_args="-abs"
[ -n "$KEY_ID" ] && gpg_args="$gpg_args --default-key $KEY_ID"
gpg $gpg_args -o $cd_writable/extra/Release.gpg $cd_writable/extra/Release
gpg --export --armor $KEY_ID > $cd_writable/extra/key.pub
cat >> $cd_writable/preseed/ubuntu.seed << EOF
oem-config	oem-config/key	string /cdrom/extra/key.pub
oem-config	oem-config/repository	string $REPO
oem-config	oem-config/extra_packages	string $pkgs
oem-config	oem-config/early_command	string $EARLY
oem-config	oem-config/late_command		string $LATE
EOF
save=$(pwd)
cd $cd_writable
mkisofs -D -r -V "${CD_TITLE:-Ubuntu}" -cache-inodes -J -l -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -o "$save/${CD_FILE:-custom.iso}" .
cd $save