#!/bin/bash -e

# Default memory allocation.
memsize=64
nics=1
if test $# -lt 1; then
	echo Usage: `basename $0` imagename "[memsize(MB)]" "[nics]"
	echo Default memsize is ${memsize}MB.
	echo Default number of NICs is $nics.
	exit 1
fi

img=${1}
memory=${2:-"$memsize"}
nics=${3:-"$nics"}
if test $# -le 3 ; then
	shift $#
else
	shift 3
fi

case $img in
/*) ;;
*) img=`pwd`/$img ;;
esac
if ! test -s "$img" ; then
	if test -s "$img.img" ; then
		img="$img".img
	fi
fi

# Sanity check that we have a root filesystem image.
if ! test -s ${img} ; then
	echo "No image!"
	exit 1
fi
name=`basename "$img"`
name=${name//.img}

# Create a temporary directory to store the kernel image and any other stuff
# which we'll need.
tmpdir=`mktemp -d ${TMPDIR:-/tmp}/bootXXXXXX`
unmount() {
	test -d ${tmpdir}/root && umount ${tmpdir}/root
	rm -fr ${tmpdir}
}
trap unmount EXIT

# Mount the filesystem for a bit.
mkdir ${tmpdir}/root
mount -o loop -t ext3 ${img} ${tmpdir}/root || exit

# Check which version of the kernel is installed.
kversion=`chroot ${tmpdir}/root rpm -q --qf '%{version}-%{release}' kernel-xenU`xenU

# Get a copy of the kernel image.
cp ${tmpdir}/root/boot/vmlinuz-${kversion} ${tmpdir}

# Ensure that the root device exists in the guest.
rootdev=`awk '{ if ( $2 == "/" ) print $1 }' ${tmpdir}/root/etc/fstab`
chroot ${tmpdir}/root MAKEDEV -x $rootdev `echo $rootdev | sed s,'[[:digit:]]*$',,g`

# Calculate module dependencies.
chroot ${tmpdir}/root depmod -a ${kversion}

# Okay, we're ready.
umount ${tmpdir}/root
rmdir ${tmpdir}/root

# Check that the dom0 xend can figure out which major/minor to emulate.  If it
# can't, then we're screwed.
if ! test -e "$rootdev" ; then
	echo "Warning! $rootdev does not exist on the dom0 host!"
	MAKEDEV -x `basename $rootdev`
fi

# Create the guest.
if test -r xmdefconfig ; then
	cp xmdefconfig ${tmpdir}/xmdefconfig
else
	touch ${tmpdir}/xmdefconfig
fi
xm create -c -f ${tmpdir}/xmdefconfig \
	name=${name} \
	kernel=${tmpdir}/vmlinuz-${kversion} \
	nics=${nics:-1} \
	memory=${memory} \
	disk=file:${img},`basename $rootdev`,w \
	root=$rootdev \
	extra="ro selinux=0 $*" \
	restart=onreboot