#!/bin/sh

#===============================================================================
# ossuary
#===============================================================================


#===============================================================================
# script usage
#===============================================================================

usage () {
# if argument passed to function echo it
[ -z "${1}" ] || echo "! ${1}"
echo "\
$(basename "$0") -m mount -f container -k gelikey 
$(basename "$0") -m umount -f container"
}

#===============================================================================
# error messages
#===============================================================================

ROOT_ERR="$(basename "$0") must be run as root"
WRONG_ARGS_ERR='wrong number of arguments passed to script'
INVALID_OPT_ERR='Invalid option:'
REQ_ARG_ERR='requires an argument'


#===============================================================================
# check if script is run as root
#===============================================================================

[ "$(id -u)" -eq 0 ] || usage "${ROOT_ERR}"


#===============================================================================
# check number of aruments passed to script
#===============================================================================

[ $# -gt 0 ] || usage "${WRONG_ARGS_ERR}"

#===============================================================================
# getopts check options passed to script
#===============================================================================

while getopts ':m:f:k:h' opt
do
  case ${opt} in
     m) mount="${OPTARG}";;
     f) container="${OPTARG}";;
     k) gelikey="${OPTARG}";;
     h) usage;;
     \?) usage "${INVALID_OPT_ERR} ${OPTARG}" 1>&2;;
     :) usage "${INVALID_OPT_ERR} ${OPTARG} ${REQ_ARG_ERR}" 1>&2;;
  esac
done
shift $((OPTIND-1))


#===============================================================================
# functions
#===============================================================================

# mount function
mount () {
    # group commands
    { 
    # mdconfig loopname from container
    loopdevice=$(mdconfig -lf "${container}" | sed 's/[ \t]*$//')

    # eli filepath
    loopcrypt="/dev/${loopdevice}.eli"

    # mdconfig create vnode from container
    loop=$(mdconfig -a -t vnode -f "${container}")

    # geli attach key to vnode
    geli attach -k "${gelikey}" "${loop}"

    # mdconfig loop device for container
    loopdevice=$(mdconfig -lf "${container}" | sed 's/[ \t]*$//')

    # path to mdconfig eli file
    loopcrypt="/dev/${loopdevice}.eli"

    # zpool name from mdconfig eli file
    poolname=$(zdb -l "${loopcrypt}" | awk -F\' '/[[:blank:]]name/ {print $2; exit;}')

    # zpool import pool
    zpool import "${poolname}"

    # mount point from zpool
    mountpoint=$(zfs get -H -o value mountpoint "${poolname}");
    } || { mdconfig -du "${loopdevice}" && exit; }
}

# umount function
umount () {
    # group commands
    {
    # mdconfig loopname from container
    loopdevice=$(mdconfig -lf "${container}" | sed 's/[ \t]*$//')

    # eli filepath
    loopcrypt="/dev/${loopdevice}.eli"

    # zpool name from eli file
    poolname=$(zdb -l "${loopcrypt}" | awk -F\' '/[[:blank:]]name/ {print $2; exit;}')

    # zfs umount poolname
    zfs umount "${poolname}"

    # zpool export poolname
    zpool export "${poolname}"
    sleep 1

    # geli detach
    geli detach "${loopcrypt}"

    # mdconfig remove md file
    mdconfig -du "${loopdevice}";
    } || { echo 'container not mounted' && exit; }
}


#===============================================================================
# mount and umount case statement
#===============================================================================

case "${mount}" in
    mount) mount;;
    umount) umount;;
    *) usage;;
esac