#!/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"
exit 1
}

#===============================================================================
# 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 ${opt} in
     m) action="${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_container () {
    [ -f "${container}" ] || usage "Container file not found"
    [ -f "${gelikey}" ] || usage "GELI key not found"

    # mdconfig create vnode
    loop=$(mdconfig -a -t vnode -f "${container}") || exit 1

    # geli attach
    geli attach -k "${gelikey}" "${loop}" || { mdconfig -du "${loop}"; exit 1; }

    loopcrypt="/dev/${loop}.eli"

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

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

# umount function
umount_container () {
    [ -n "${container}" ] || usage "Container path required (-f)"

    # find associated md device
    loopdevice=$(mdconfig -lv | grep "${container}" | awk '{print $1}')
    
    if [ -z "${loopdevice}" ]; then
        echo "Error: Container not found in mdconfig list."
        exit 1
    fi

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

    # clean tear down
    zfs umount "${poolname}" 2>/dev/null
    zpool export "${poolname}"
    sleep 1
    geli detach "${loopcrypt}"
    mdconfig -du "${loopdevice}"
}

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

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