kali-vmdk2tar.in

#!/bin/bash

m4_include(utils)

usage() {
  cat <<EOF
usage: ${0##*/} input [output]

    -h                  Print this help message
    -n <number>         Partition number for rootfs, defaults to 1

EOF
}

partition=1
while getopts ':hn:' flag; do
  case $flag in
    h)
      usage
      exit 0
      ;;
    n)
      partition=$OPTARG
      [[ $partition -ge 1 ]] || die "%s: invalid partition number" "${0##*/}"
      ;;
    :)
      die '%s: option requires an argument -- '\''%s'\' "${0##*/}" "$OPTARG"
      ;;
    ?)
      die '%s: invalid option -- '\''%s'\' "${0##*/}" "$OPTARG"
      ;;
  esac
done
shift $(( OPTIND - 1 ))

if [ "$#" -lt 1 ] || [ "$#" -gt 2 ]; then
  die "%s: invalid parameters" "${0##*/}"
fi

input=$(realpath "$1" 2>/dev/null)
input_extension="${input##*.}"
output=$(realpath "$2" 2>/dev/null)
if [[ "$2" == "" ]]; then
  output=$(basename "$input" .$input_extension)
  output=$(dirname "$input")"/$output.tar.zst"
fi
compression=${output##*.}
taropt=""
case $compression in
  zst | zstd)
    taropt="--zstd"
    ;;
  bz2 | bzip2)
    taropt="--bzip2"
    ;;
  xz)
    taropt="--xz"
    ;;
  lz)
    taropt="--lzip"
    ;;
  lzma)
    taropt="--lzma"
    ;;
  lzop)
    taropt="--lzop"
    ;;
  gz)
    taropt="--gzip"
    ;;
esac

(( EUID == 0 )) || die 'This script must be run with root privileges'

[[ -f "$input" ]] || die "input is not a file"
[[ ! -e "$output" ]] || die "output file exists"


# load nbd kernel module
# first check if it has been loaded before
if lsmod | grep "nbd" &> /dev/null; then
  nbdloaded="n"
else
  modprobe nbd || die "%s: cannot load nbd kernel module" "${0##*/}"
  while [ ! -e "/dev/nbd0" ]; do
    sleep 1
  done
  nbdloaded="y"
fi

# https://stackoverflow.com/a/22608727
for x in /sys/class/block/nbd* ; do
  S=$(cat $x/size)
  if [ "$S" == "0" ] ; then
    block=$(basename $x)
    break
  fi
done

# check for qemu-nbd
program_exists qemu-nbd || die "%s: this script depends on qemu-nbd, please install it before trying again" "${0##*/}"
qemu-nbd -c "/dev/$block" "$input" || die "%s: cannot connect '%s' to '%s'" "${0##*/}" "${block}p${partition}" "$input"
# wait until partition becomes available
while [ ! -e "/dev/${block}p${partition}" ]; do
  sleep 1
done

mountpoint=$(mktemp -d /tmp/vmdk2tar.XXXXXXXXX)
mount -t ext4 -o ro "/dev/${block}p${partition}" "$mountpoint" || die "%s: cannot mount '%s'" "${0##*/}" "${block}p${partition}"
previouspwd=$PWD
cd $mountpoint
tar $taropt --one-file-system -cf $output . || die "%s: cannot make an archive from given rootfs"
cd $previouspwd
umount "$mountpoint" || die "%s: cannot unmount '%s'" "${0##*/}" "$mountpoint"
rmdir "$mountpoint" || true
qemu-nbd -d "/dev/$block" || die "%s: cannot disconnect '%s'" "${0##*/}" "${block}p${partition}"
# unload nbd module if it was loaded by this script
[[ $nbdloaded == "y" ]] && (rmmod nbd || die "%s: cannot unload nbd kernel module" "${0##*/}")