#!/bin/sh

example_runtime_usage() {
	echo 'Examples:'
	echo ' qemu -kernel /boot/bzImage -append "root=/dev/hda init=/sbin/init rootfstype=ext2 ro" ../root_fs'
	echo ' qemu -kernel /usr/src/linux/arch/i386/boot/bzImage -append "root=/dev/hda init=/sbin/init rootfstype=ext2 ro" ../root_fs'
	echo ' qemu -kernel /usr/src/linux/arch/i386/boot/bzImage -append "root=/dev/hda ro" ../root_fs'
	echo ' qemu -kernel bzImage -append "root=/dev/hda ro" root_fs'
	echo ' qemu-system-x86_64 -kernel bzImage -append "root=/dev/hda ro force_personality32" root_fs'
	# initrd...  qemu  -no-kqemu -m 64 -initrd initrd.img  -append "console=ttyS0,115200n8 console=tty0 clocksource=pit root=/dev/hda vga=ext" -kernel vmlinux linux-0.2.img-localtime  -nographic
}

if [ ! -d "$1" ]; then
	example_runtime_usage
	exit 1
fi

if ! cd $1 ; then
	echo Unable to cd $1 >&2
	exit 1
fi


umask 022

rom=/rom

mkdir -p {usr/,}{s,}bin etc/init.d proc/self dev/shm root tmp ./${rom}

chmod 700 root
chmod 1777 tmp

################
################
cat <<EOF > etc/init.d/rcS 
#!/bin/sh
rom=$rom
mount -a
mount tmpfs \$rom -t tmpfs
mkdir -p \$rom/proc \$rom/dev \$rom/ro \$rom/tmp
mount -o bind /dev \$rom/dev
mount -o bind /proc \$rom/proc
busybox cp -a bin etc lib root sbin usr \$rom/
chmod 1777 \$rom/tmp
pivot_root \$rom/ \$rom/ro
EOF
chmod +x etc/init.d/rcS

##################
## /etc/inittab ##
##################
cat <<EOF > etc/inittab
null::sysinit:/bin/mount -o remount,ro /
null::sysinit:/bin/mount -t proc proc /proc
null::sysinit:/bin/mount -a
null::sysinit:/sbin/sysctl -w kernel.hostname=qemu
null::sysinit:/sbin/sysctl -w kernel.domainname=busybox.net
null::sysinit:/sbin/ifconfig lo 127.0.0.1 up
null::sysinit:/sbin/route add -net 127.0.0.0 netmask 255.0.0.0 lo
::sysinit:/etc/init.d/rcS
#::askfirst:-/bin/sh
::respawn:/bin/sh
#tty1::respawn:/sbin/getty 38400 tty1
#tty2::askfirst:-/bin/sh
#tty3::askfirst:-/bin/sh
#tty4::askfirst:-/bin/sh
#tty4::respawn:/sbin/getty 38400 tty5
#tty5::respawn:/sbin/getty 38400 tty6
::restart:/sbin/init
::ctrlaltdel:/sbin/reboot
::shutdown:/bin/umount -a -r
::shutdown:/sbin/swapoff -a
EOF


cp /bin/busybox bin/

for f in $(ldd bin/busybox | awk '{print $3}' ) $(readelf -e bin/busybox | grep "program interpreter:"|awk '{print $4}'|sed s/']'//); do
	[[ -f $f ]] && {
		mkdir -p ./$(dirname $f);
		cp ${f} ./${f} ;
	}
done

if [ ! -L proc/self/exe ]; then
	cd proc/self
	ln -s /bin/busybox exe

	if [ -e /proc/self/fd ] ; then
		ln -fs /proc/self/fd fd 2> /dev/null
		ln -fs fd/0 stdin
		ln -fs fd/1 stdout
		ln -fs fd/2 stderr
	fi
	cd ../../
fi

cd etc
ln -sf ../proc/mounts mtab
cp /etc/protocols .
#grep -v ^# /etc/protocols > protocols
#  | awk '{print $1, $2, $3}'|grep [0-9] > protocols
cd ..

cd dev

ln -sf /proc/kcore core

# ttys
for i in `seq 0 9`; do
	[ ! -e tty$i ] && mknod tty$i c 4 $i
done
[ ! -e tty ] && (mknod -m 666 tty c 5 0 2> /dev/null || echo cant mknod for tty)

[ ! -e null ] &&  (mknod -m 666 null c 1 3 2> /dev/null || echo cant mknod for null)
[ ! -e zero ] && (mknod -m 666 zero c 1 5 2> /dev/null || echo cant mknod for zero)
[ ! -e urandom ] && (mknod -m 644 urandom c 1 9 2> /dev/null || echo cant mknod for urandom)
[ ! -e random ] && mknod random c 1 8
[ ! -e console ] && mknod console c 5 1
[ ! -e full ] && mknod full c 1 7
[ ! -e kmem ] && mknod kmem c 1 2
[ ! -e mem ] && mknod mem c 1 1
[ ! -e port ] && mknod port c 1 4

# IDE devs
[ ! -e hda ] && mknod hda b 3 0
[ ! -e hdb ] && mknod hdb b 3 64
[ ! -e hdc ] && mknod hdc b 22 0
[ ! -e hdd ] && mknod hdd b 22 64

# loop devs
for i in `seq 0 7`; do [ ! -e loop$i ] && mknod loop$i b 7 $i; done

# ram devs
for i in `seq 0 9`; do [ ! -e  ram$i ] && mknod ram$i b 1 $i ; done
[ ! -L ram ] && ln -s ram1 ram

# virtual console screen devs
for i in `seq 0 9`; do [ ! -e vcs$i ] && mknod vcs$i b 7 $i; done

chown root:tty tty 2> /dev/null
chown root:sys null zero 2> /dev/null
cd -


################
## /etc/fstab ##
################
cat <<EOF > etc/fstab
#/dev/root      /               ro,defaults  defaults 0 0
proc            /proc           proc    defaults 0 0
#none           /dev            devfs   defaults 0 0
devpts          /dev/pts        devpts  defaults,gid=5,mode=620  0 0
tmpfs           /tmp            tmpfs   defaults 0 0
tmpfs           $rom            tmpfs   defaults 0 0
tmpfs           /dev/shm        tmpfs   defaults 0 0
EOF

chroot . /bin/busybox --install -s

#mksquashfs . root_fs -noappend -e root_fs
#chmod 755 root_fs

if type -p genext2fs > /dev/null; then
	REALSIZE=$(LANG=C du ./ -s -c -k | grep total | awk '{print $1}')
	ADDTOROOTSIZE=$([ $REALSIZE -ge 20000 ] && echo 16384 || echo 16)
	ADDTOROOTSIZE=$([ $REALSIZE -ge 20000 ] && echo 16384 || echo 16384)
	SIZE=$(( $REALSIZE + $ADDTOROOTSIZE ))
	#[[ $SIZE -le 2600 ]] && SIZE=2600
	INODES=$(($(find . | wc -l) + 400))
	genext2fs -U -P -i ${INODES} -b ${SIZE} -q -d . ../root_fs
fi


example_runtime_usage