#!/bin/sh

usage()
{
	cat >&2 << EOF

Usage: ${0} [OPTION]... <-o outfile> [version]

Options:
  -d confdir  Specify an alternative configuration directory.
  -k          Keep temporary directory used to make the image.
  -o outfile  Write to outfile.
  -r root     Override ROOT setting in mkinitrd.conf.

See ${0}(8) for further details.
EOF
	exit 1

}

# Defaults
keep="n"
CONFDIR="/etc/mkinitramfs"

while getopts "d:ko:r:" flag; do
	case $flag in
	d)
		CONFDIR="${OPTAGS}"
		if [ ! d "${CONFDIR}" ]; then
			echo "${0}: ${CONFDIR}: Not a directory" >&2
			exit 1
		fi
		;;
	o)
		outfile="${OPTARG}"
		;;
	v)
		version="${OPTARG}"
		;;
	k)
		keep="y"
		;;
	esac
done

shift $((${OPTIND} - 1))

. ${CONFDIR}/initramfs.conf

if [ x${outfile} = x ] || [ ${#} -ne 1 ]; then
	usage
fi

if [ -d ${outfile} ]; then
	echo "${outfile} is a directory"
	exit 1
fi

if [ ! -e /lib/modules/${version} ]; then
	echo "Cannot find /lib/modules/${version}"
	exit 1
fi

TMPDIR=$(mktemp -d) || exit 1
mkdir -p ${TMPDIR}/modules ${TMPDIR}/conf ${TMPDIR}/etc
mkdir -p ${TMPDIR}/bin ${TMPDIR}/lib ${TMPDIR}/scripts

for x in $(sed -e '/^#/d' ${CONFDIR}/modules); do
	for y in $(modprobe --set-version=${version} --show-depends ${x} | awk '{ print $2 }'); do
		# Prune duplicates
		if [ -e ${TMPDIR}/modules/$(basename ${y}) ]; then
			continue
		fi

		ln -s ${y} ${TMPDIR}/modules
		echo $(basename ${y}) >>${TMPDIR}/conf/modules
	done
done

# Have to do each file, because cpio --dereference doesn't recurse down
# symlinks.

ln -s /usr/lib/klibc/bin/* ${TMPDIR}/bin
ln -s /usr/lib/klibc/lib/* ${TMPDIR}/lib
ln -s /usr/share/initramfs-tools/init ${TMPDIR}/init
ln -s /usr/share/initramfs-tools/scripts/* ${TMPDIR}/scripts
ln -s ${CONFDIR}/initramfs.conf ${TMPDIR}/conf
ln -s /etc/udev ${TMPDIR}/etc

# Hack until udev is built with klibc
ln -s /sbin/udev ${TMPDIR}/bin
ln -s /sbin/udevstart ${TMPDIR}/bin
ln -s /lib/libc.so.* ${TMPDIR}/lib
ln -s /lib/ld*.so.* ${TMPDIR}/lib
rm ${TMPDIR}/lib/*lsb*

# Busybox
if [ "x${BUSYBOX}" = "xy" ]; then
	rm ${TMPDIR}/bin/sh
	ln -s /bin/busybox ${TMPDIR}/bin/sh
fi

# Raid
ln -s /sbin/mdadm ${TMPDIR}/bin
ln -s /sbin/mdrun ${TMPDIR}/bin
ln -s /bin/grep ${TMPDIR}/bin
ln -s /bin/sed ${TMPDIR}/bin

(cd ${TMPDIR} && find . | cpio --quiet --dereference -o -H newc | gzip -9 >${outfile})

if [ "${keep}" = "y" ]; then
	echo "Working files in ${TMPDIR}"
else
	rm -rf "${TMPDIR}"
fi