#!/bin/bash
#https://gist.githubusercontent.com/dbehnke/ad19ca8f1ccf80aebca5/raw/716672ae3a9ccf9c3181a898e3014880d19d68b2/luksloopback.sh
loopdevice=$(losetup -f)
#https://stackoverflow.com/questions/7358611/get-users-home-directory-when-they-run-a-script-as-root
loopfile=$(getent passwd "$SUDO_USER" | cut -d: -f6)/work/expect-dialog-ca.git.loop

#megabytes
loopsize=256

#/dev/mapper/xxxxx when open
cryptmapper=expect-dialog-ca.git

makefilesystem=ext4

#mountpoint of uncrypted device
#https://stackoverflow.com/questions/7358611/get-users-home-directory-when-they-run-a-script-as-root
mountpoint=$(getent passwd "$SUDO_USER" | cut -d: -f6)/work/expect-dialog-ca.git.mount

#creates a new file
create() {
  echo creating a file with size ${loopsize}M with random bits.. this could take a while..
  dd if=/dev/urandom of="$loopfile" bs=1M count="$loopsize"
  losetup "$loopdevice" "$loopfile"
  cryptsetup luksFormat -y "$loopdevice"
  cryptsetup open "$loopdevice" "$cryptmapper"
  sudo mkfs."$makefilesystem" "/dev/mapper/$cryptmapper"
  cryptsetup close "$cryptmapper"
  losetup -d "$loopdevice"
  losetup -a
}

#mounts crypted loopback file
open() {
  losetup "$loopdevice" "$loopfile"
  cryptsetup open "$loopdevice" "$cryptmapper"
  mount "/dev/mapper/$cryptmapper" "$mountpoint"
}

#unmounts previously mounted loopback file
close() {
  umount "$mountpoint"
  cryptsetup close "$cryptmapper"
  losetup -d $(losetup -a |grep "$loopfile"|cut -d ':' -f 1)
}

if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root" 1>&2
   exit 1
fi

echo loopdevice  "$loopdevice"
echo loopfile    "$loopfile"
echo loopsize    "$loopsize"
echo cryptmapper "$cryptmapper"
echo filesystem  "$makefilesystem"
echo mountpoint  "$mountpoint"
echo command     "$1"

$1