#!/bin/bash

#This script is used to start-up a KVM-based virtual machine with a specific
#kernel, specified via command line with -k option

#--------------------------------------------------#

#virt-xml <domain> --edit --boot kernel=args=<args>
VIRTXML_BIN=`which virt-xml 2> /dev/null`
DEFAULT_OPS="ro vconsole.font=latarcyrheb-sun16 LANG=en_CA.UTF-8 console=ttyS0
crashkernel=128M"

# Display usage help function
usage() {
	echo
	echo "boot_kernel.sh: start a virtual machine with a direct kernel"
	echo
	echo "Usage: boot_kernel.sh -d <vm_name> -k <kernel> -r <root_dev> -o \"<kernel_opts>\""
	echo
	echo "-d: Specify the virtual machine name (domain name)"
	echo "-k: Kernel executable path to be loaded in the virtual machine"
	echo "-o: Kernel Options command line arguments (please use \"\")"
	echo "-r: Root device, partition where rootfs is stored inside VM"
	echo "-h: Show this help"
}


if [ -z $VIRTXML_BIN ]; then
	echo "virt-xml executable not found..."
	echo "Please make sure your system has virt-install package installed"
	echo
	exit
fi

add_kernel_to_xml() {
	echo $VIRTXML_BIN --edit --boot kernel=$KERNEL_PATH kernel_args=$KERNEL_OPS
}


while getopts "d:hk:o:r:" ARG; do
	case $ARG in
		d)	#domain name
			DOMAIN_NAME=$OPTARG
			;;
		h)
			#help menu
			usage
			;;
		k)	#kernel path
			KERNEL_PATH=$OPTARG
			;;
		o)
			#kernel_ops
			KERNEL_OPS=$OPTARG
			;;
		r)
			#root_device
			ROOT_DEV=$OPTARG
			;;
		*)
			usage
			exit
			;;
			
	esac
done

#Ensure $KERNEL_PATH is valid
if [ -z $KERNEL_PATH ]; then
	echo "Kernel image not specified..."
	usage
	exit 1
fi

if [ ! -f $KERNEL_PATH ]; then
	echo "Kernel image not found...exiting"
	exit 1
fi

#add_kernel_to_xml
$VIRTXML_BIN $DOMAIN_NAME --edit --boot kernel=$KERNEL_PATH

#Set kernel_args
if [ -z "$KERNEL_OPS" ]; then
	$VIRTXML_BIN $DOMAIN_NAME --edit --boot kernel_args="root=$ROOT_DEV $DEFAULT_OPS"
else
	$VIRTXML_BIN $DOMAIN_NAME --edit --boot kernel=$KERNEL_PATH --boot kernel_args="root=$ROOT_DEV ro $KERNEL_OPS"
fi

#Starting VM
virsh start $DOMAIN_NAME