#!/bin/sh

who=$(id -u)
if [ $who -ne 0 ]; then
  echo 'Exit. System update must be run as root.'
  exit 1
fi

cd /
umount -f /etc
mount -o remount,rw /

check_exit() {
	if [ $? -ne 0 ];then
		echo "Update failed."
		exit 1
	fi
}

extract_from_file() {
        cat $1 | gunzip -c | tar -xf -
	check_exit
}

extract_from_ssh() {
        ssh $1 "cat $2" | gunzip -c | tar -xf -
	check_exit
}

extract_from_http() {
        wget -O - $1 | gunzip -c | tar -xf -
	check_exit
}
                
case $1 in
        file://*|/*)
                url=$(echo $1|sed -e "s#file://##")
		echo "Updating system from $1"
                extract_from_file $url
                ;;
        ssh://*)
                host=$(echo $1|sed -e "s#ssh://\(.*\):.*#\1#")
                file=$(echo $1|sed -e "s#ssh://.*:\(.*\)#\1#")
		echo "Updating system from $1"
                extract_from_ssh $host $file
                ;;
        http://*|ftp://*)
		echo "Updating system from $1"
                extract_from_http $1
                ;;
        *)
                echo "No or wrong uri given. exit."
		echo "Use one of the following uri:"
		echo "http://myserver/myupdate.tar.gz"
		echo "ssh://myuser@myserver:/my/path/myupdate.tar.gz"
		echo "file:///mypath/myupdate.tar.gz"
                exit 1
                ;;
esac

sync
mount -o bind /etc /tmp/.cfgfs/root

echo "Update sucessful. You should reboot now."