#! /bin/sh
# Created by Tobias Powalowski <tpowa@archlinux.org>
# Settings
APPNAME=$(basename "${0}")
CONFIG="/etc/mksyslinux.conf"
export TEMPDIR=$(mktemp /tmp/mksyslinux.XXX)
TMPDIR=$(mktemp -d /tmp/mksyslinux-image.XXX)
BOOTDIRNAME=boot/syslinux

usage ()
{
    echo "${APPNAME}: usage"
    echo "WRITING TO DEVICE:"
    echo "- PREPARATION: Your device must have a bootable first partition in FAT16 format!"
    echo "- ATTENTION: The MBR of your DEVICE will be overwritten! You have been warned!"
    echo ""
    echo "CREATING AN IMAGE FILE:"
    echo "- For creating an image file use the -i=IMAGEFILE switch"
    echo "- use 'dd if=<yourimage> of=<yourdevice>' to write to your device afterwards."
    echo ""
    echo "PARAMETERS:"
    echo "  -d=DEVICE        Your DEVICE first partition from /dev/xxx tree to install"
    echo "  -i=IMAGENAME     Your IMAGENAME"
    echo "  -c=CONFIG        Use CONFIG file. default: /etc/mksyslinux.conf"
    echo "  -h               This message."
    exit 1
}

[ "$1" == "" ] && usage && exit 1


while [ $# -gt 0 ]; do
	case $1 in
		-c=*|--c=*) CONFIG="$(echo $1 | awk -F= '{print $2;}')" ;;
		-d=*|--d=*) DEVICE="$(echo $1 | awk -F= '{print $2;}')" ;;
		-i=*|--i=*) IMAGENAME="$(echo $1 | awk -F= '{print $2;}')" ;;
		-h|--h|?) usage ;; 
		*) usage ;;
		esac
	shift
done

if [ ! -f "${CONFIG}" ]; then
	echo "config file '${CONFIG}' cannot be found, aborting..."
    exit 1
fi

if [ "${IMAGENAME}" = "" ]; then
	if [ "${DEVICE}" = "" ]; then 
		echo "ERROR: No DEVICE name specified, please use the -d option"
	 	exit 1
	fi
fi

if ! [ $UID -eq 0 ]; then 
	echo "ERROR: only works when run as root!"
	exit 1
fi

. "${CONFIG}"
# export for mkinitcpio
[ -n "${APPENDBOOTMESSAGE}" ] && export APPENDBOOTMESSAGE
[ -n "${APPENDBOOTMESSAGE_SYSLINUX}" ] && export APPENDBOOTMESSAGE_SYSLINUX
[ -n "${APPENDOPTIONSBOOTMESSAGE}" ] && export APPENDOPTIONSBOOTMESSAGE

MBRDEVICE="$(echo ${DEVICE} | sed -e 's/[0-9]//g')"

export RUNPROGRAM="${APPNAME}"
[ "${BOOTMESSAGE}" = "" ] && export BOOTMESSAGE=$(mktemp /tmp/bootmessage.XXXX)
[ "${OPTIONSBOOTMESSAGE}" = "" ] && export OPTIONSBOOTMESSAGE=$(mktemp /tmp/optionsbootmessage.XXXX)
export USEKERNEL=${VERSION}
# begin script
[ -e ${TEMPDIR} ] && rm -r ${TEMPDIR}
mkdir -p ${TEMPDIR}
echo ":: Mounting ${DEVICE} ..."
if ! [ "${IMAGENAME}" = "" ]; then
	modprobe loop
else
	mount ${DEVICE} ${TEMPDIR} || exit 1
fi
mkdir -p ${TEMPDIR}/${BOOTDIRNAME}
# prepare syslinux bootloader
install -m755 /usr/lib/syslinux/isolinux.bin ${TEMPDIR}/${BOOTDIRNAME}/isolinux.bin
for i in /usr/lib/syslinux/*.c32; do
    install -m644 $i ${TEMPDIR}/${BOOTDIRNAME}/$(basename $i)
done
install -m644 /usr/share/hwdata/pci.ids ${TEMPDIR}/${BOOTDIRNAME}/pci.ids

# create syslinux.cfg
echo ":: Creating syslinux.cfg ..."
if [ "${SYSLINUXCFG}" = "" ]; then
	[ -e ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg ] && rm ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg
	echo "prompt ${PROMPT}" >> ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg
	echo "timeout ${TIMEOUT}" >> ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg
	echo "display boot.msg" >> ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg
	echo "F1 boot.msg" >>  ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg
	echo "F2 options.msg" >>  ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg
	echo "default parabola"  >> ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg
	echo "label parabola" >> ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg
	echo "kernel /boot/vmlinuz" >> ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg
	echo "append initrd=/boot/initrd.img ${KERNEL_BOOT_OPTIONS}" >> ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg
else
	sed "s|@@PROMPT@@|${PROMPT}|g;s|@@TIMEOUT@@|${TIMEOUT}|g;s|@@KERNEL_BOOT_OPTIONS@@|${KERNEL_BOOT_OPTIONS}|g" \
		${SYSLINUXCFG} > ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg
fi
[ ! -s ${TEMPDIR}/${BOOTDIRNAME}/syslinux.cfg ] && echo "No syslinux.cfg found" && exit 1
echo ":: Calling mkinitcpio CONFIG=${MKINITCPIO_CONFIG} KERNEL=${VERSION} ..." 
# generate initramdisk
echo ":: Creating initramdisk ..."
	mkinitcpio -c ${MKINITCPIO_CONFIG} -k ${VERSION} -g ${TEMPDIR}/boot/initrd.img
echo ":: Using ${KERNEL} as image kernel ..."
	install -m644 ${KERNEL} ${TEMPDIR}/boot/vmlinuz
	install -m644 ${BOOTMESSAGE} ${TEMPDIR}/${BOOTDIRNAME}/boot.msg
	install -m644 ${OPTIONSBOOTMESSAGE} ${TEMPDIR}/${BOOTDIRNAME}/options.msg
	[ ! -s ${TEMPDIR}/${BOOTDIRNAME}/boot.msg ] && echo 'ERROR:no boot.msg found, aborting!' && exit 1
	[ ! -s ${TEMPDIR}/${BOOTDIRNAME}/options.msg ] && echo 'ERROR:no options.msg found, aborting!' && exit 1
if ! [ "${IMAGENAME}" = "" ]; then
	# ext2 overhead's upper bound is 6%
	# empirically tested up to 1GB
	rootsize=$(du -bs ${TEMPDIR}|cut -f1)
	IMGSZ=$(( (${rootsize}*106)/100/512 + 1)) # image size in sectors
	# create the filesystem image file
	dd if=/dev/zero of="${IMAGENAME}" bs=512 count="${IMGSZ}"
	# create a filesystem on the image
	mkfs.vfat "${IMAGENAME}"
	mount -o loop ${IMAGENAME} ${TMPDIR} || exit 1
	cp -r "${TEMPDIR}"/* "$TMPDIR"
	umount ${TMPDIR}
else
	echo ":: Unmounting ${DEVICE} ..."
	umount ${TEMPDIR} || exit 1
fi
if ! [ "${IMAGENAME}" = "" ]; then
	echo ":: Installing SYSLINUX on ${IMAGENAME} ..."
	syslinux ${IMAGENAME} && echo "Installation completed."
else
	echo ":: Installing MBR on ${MBRDEVICE} ..."
	cat ${MBR} > ${MBRDEVICE}
	echo ":: Installing SYSLINUX on ${DEVICE} ..."
	syslinux -t offset ${DEVICE} && echo "Installation completed."
fi
# clean /tmp
rm -r ${TEMPDIR}
! [ ${IMAGENAME} = "" ] && rm -r ${TMPDIR}