#!/bin/sh
################################################
# Declarations
################################################
this_script=${0##*/}
name_default=".crypt.dsk"
path_default="/home"
vnode_default="svnd0c"
mountpoint_default="/crypt"
size="100"
# command paths
dd="/bin/dd"
mkdir="/bin/mkdir"
newfs="/sbin/newfs"
mount="/sbin/mount"
umount="/sbin/umount"
vnconfig="/sbin/vnconfig"
cmds="$dd $mkdir $newfs $mount $umount $vnconfig"

################################################
# Functions
################################################
f_usage () {
  echo "Usage: $this_script -(c|m|u)"
  echo " -c = create"
  echo " -m = mount"
  echo " -u = unmount"
}

f_getvar () {
  echo -n "$2 [$3]: "
  read entry
  entry=${entry:=$3}
  eval $1=$entry
}

f_gather () {
  while [[ -z $vnode ]] || [[ -z $mountpoint ]]; do
    f_getvar vnode "Vnode" $vnode_default
    f_getvar mountpoint "Mount point" $mountpoint_default
  done
  vdev="/dev/$vnode"
  if [[ $1 = "-c" ]] || [[ $1 = "-m" ]]; then
    while [[ -z $name ]] || [[ -z $path ]]; do
      f_getvar path "Disk image path" $path_default
      f_getvar name "Disk image name" $name_default
    done
    image="$path/$name"
  fi
}

f_mount () {
  ## Check mount point
  if [ ! -d $mountpoint ]; then
    echo "Mount point $mountpoint does not exist."
    f_getvar yesno "Create it?" "y"
    if [ $yesno = "y" ]; then
      $mkdir $mountpoint
    fi
  fi
  if [ -d $mountpoint ]; then
    ## Assign an encrypted virtual inode
    $vnconfig -ck -v $vdev $image
    if [ $1 = "-c" ]; then
      ## Format the disk
      $newfs $vnode
    fi
    ## Mount it
    $mount $vdev $mountpoint
  fi
}

f_umount () {
  ## Unmount it
  $umount $mountpoint
  ## Unassign the virtual inode
  $vnconfig -u -v $vdev
}

f_create () {
  yesno="y"
  if [ -f $image ]; then
    yesno="n"
    echo "Disk image $image already exists."
    f_getvar yesno "Overwrite it?" $yesno
  fi
  if [ $yesno = "y" ]; then
    # Warning: there is no bounds check on $size
    f_getvar size "Enter desired size of $image in MB" $size
    echo "Creating $image..."
    $dd if=/dev/arandom of=$image bs=1048576 count=$size
    f_mount $1
  fi
}

################################################
# Main
################################################
for i in `echo $cmds`; do
  if [ ! -x $i ]; then
    missing="$missing $i"
  fi
done
if [[ -z $missing ]]; then
  if [[ $# = '1' ]]; then
    f_gather $1
    case $1 in
    '-m')
       if [[ -f $image ]]; then
         f_mount $1
       else
         echo "The $image does not exist."
       fi
       ;;
    '-u')
       f_umount $1
       ;;
    '-c')
       f_create $1
       ;;
    *)
       f_usage
       ;;
    esac
  else
    f_usage
  fi
else
  for i in `echo $missing`; do
    echo "Missing: $i"
  done
fi