#!/bin/sh

PATH=/bin

/bin/busybox --install
busybox sleep 1
busybox mount -t proc proc /proc
busybox mount -t sysfs sysfs /sys
busybox mount -t devtmpfs none /dev

root_sfs=""
root=""
overlay_dev=""
singleuser=0

for param in `cat /proc/cmdline`; do
	case $param in
	root=*)
		root="${param##root=}"
		;;
	root_sfs=*)
		root_sfs="${param##root_sfs=}"
		;;
	overlay_dev=*)
		overlay_dev="${param##overlay_dev=}"
		;;
	single*)
		singleuser=1
		;;
	esac
done

if [ -z "${root}" ]; then
	echo "No root drive specified!"
	exec /bin/busybox sh
fi

if [ -z "${root_sfs}" ]; then
	echo "No squashfs image specified!"
	exec /bin/busybox sh
fi

while [ ! -e ${root} ]; do
	echo "Waiting for root"
	busybox sleep 1
done

# file system setup
mount ${root} /images

if [ ! -e /images/${root_sfs} ]; then
	echo "${root_sfs} not found!"
	exec /bin/busybox sh
	exit 1
fi

mount -t squashfs /images/${root_sfs} /newroot

if [ ! -z "$overlay_dev" ]; then
	while [ ! -e ${overlay_dev} ]; do
		echo "Waiting for overlay device"
		busybox sleep 1
	done

	mount ${overlay_dev} /newroot/cfg/overlay
	chroot /newroot mount -n -t overlay overlay -olowerdir=/cfg/preserve/etc,upperdir=/cfg/overlay/etc,workdir=/cfg/overlay/etc_work /etc
else
	chroot /newroot mount -n --bind /cfg/preserve/etc /etc
fi

# cleanup mounts
umount -l /images
umount -l /dev
umount /sys
umount /proc

if [ "$singleuser" == "1" ]; then
	unset -v singleuser overlay_dev root root_sfs
	exec /bin/busybox switch_root /newroot /bin/bash
fi

unset -v singleuser overlay_dev root root_sfs
exec /bin/busybox switch_root /newroot /bin/init