heads/initrd/bin/usb-boot

#!/bin/sh
. /etc/functions

while getopts "b:e:r:a:" arg; do
	case $arg in
		b) bootdir="$OPTARG" ;;
		e) entry="$OPTARG" ;;
		r) cmdremove="$OPTARG" ;;
		a) cmdadd="$OPTARG" ;;
	esac
done

kexectype=`echo $entry | cut -d\| -f2`
kexecparams=`echo $entry | cut -d\| -f3- | tr '|' '\n'`
kexeccmd="kexec"

fix_file_path() {
	filepath=`find $bootdir -path "*$firstval" | tail -1`
	if ! [ -r $filepath ]; then
		die "failed to find file $firstval"
	fi
}

adjust_cmd_line() {
	if [ -n "$cmdremove" ]; then
		for i in $cmdremove; do
			cmdline="${cmdline//$i/}"
		done
	fi

	if [ -n "$cmdadd" ]; then
		cmdline="$cmdline $cmdadd"
	fi
}

first_module=y
while read line
do
	key=`echo $line | cut -d\  -f1`
	firstval=`echo $line | cut -d\  -f2`
	restval=`echo $line | cut -d\  -f3-`
	if [ "$key" = "kernel" ]; then
		fix_file_path
		if [ "$kexectype" = "multiboot" ]; then
			# always overload xen and with custom arguments
			# TODO: control this replacement via flag
			kexeccmd="$kexeccmd -l /bin/xen.gz"
			kexeccmd="$kexeccmd --command-line \"no-real-mode reboot=no\""
		else
			kexeccmd="$kexeccmd -l $filepath"
		fi
	fi
	if [ "$key" = "module" ]; then
		fix_file_path
		cmdline="$restval"
		if [ -n $first_module ]; then
			adjust_cmd_line
			unset first_module
		fi
		kexeccmd="$kexeccmd --module \"$filepath $cmdline\""
	fi
	if [ "$key" = "initrd" ]; then
		fix_file_path
		kexeccmd="$kexeccmd --initrd=$filepath"
	fi
	if [ "$key" = "append" ]; then
		cmdline="$firstval $restval"
		adjust_cmd_line
		kexeccmd="$kexeccmd --append=\"$cmdline\""
	fi
done << EOF
$kexecparams
EOF

echo "Loading the new kernel:"
echo "$kexeccmd"
eval "$kexeccmd" \
|| die "Failed to load the new kernel"

echo "Starting the new kernel"
exec kexec -e