#!/bin/sh
###########################################################################
#
# Copyright (c) 2022-2023 Diality Inc. - All Rights Reserved.
#
# THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
# WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
#
# @file    crypt_setup.sh
#
# @author  (last)      Behrouz NematiPour
# @date    (last)      15-May-2023
# @author  (original)  Behrouz NematiPour
# @date    (original)  15-May-2023
#
############################################################################

IS_MOUNTED=0

ERR_CRYPTSETUP_UNKNOWN=100

ERR_CRYPTSETUP_USAGE=101
ERR_CRYPTSETUP_PASSWORD=102

ERR_CRYPTSETUP_UMOUNT=111
ERR_CRYPTSETUP_CLOSE=112

ERR_CRYPTSETUP_CREATE_MKDIR=121
ERR_CRYPTSETUP_CREATE_FORMAT=122
ERR_CRYPTSETUP_CREATE_OPEN=123
ERR_CRYPTSETUP_CREATE_MKFS=124
ERR_CRYPTSETUP_CREATE_MOUNT=125

ERR_CRYPTSETUP_MOUNT_TYPE=131
ERR_CRYPTSETUP_MOUNT_OPEN=132
ERR_CRYPTSETUP_MOUNT_MOUNT=133
ERR_CRYPTSETUP_MOUNT_ISMOUNT=134 # is used in Application do not modify [DeviceController]
ERR_CRYPTSETUP_MOUNT_CRC=135

LOC_DEV="/dev/mmcblk0p7"
LOC_DIR="configurations"
LOC_MAP="/dev/mapper/"$LOC_DIR
LOC_VAR="/var/"$LOC_DIR
LOC_CRC="settings.crc"
LOC_CFG="/home/root/.config"

DEV_TYP="crypto_LUKS"
DEV_MNT="/dev/mapper/configurations on /var/configurations type ext4 (rw,relatime)"

function isEncrypted  () {
    if [ "$( blkid | grep "$LOC_DEV" | grep "TYPE=$DEV_TYP" )" != "" ]; then
        echo "not an encrypted partition"
        exit $ERR_CRYPTSETUP_MOUNT_TYPE
    fi
}

function isMounted() {
    if [ "$( sudo mount | grep "$DEV_MNT" )" != "" ]; then
        echo "partition already mounted"
        return $IS_MOUNTED
    fi
    return 1
}

function checkPassword() {
    if [ "$PASSWORD" == "" ]; then
        echo "setup command missing password argument"
        exit $ERR_CRYPTSETUP_PASSWORD
    fi
}

function checkShaSum() {
    if [ "$(whoami)" == "root" ]; then
      cd "$LOC_CFG"
    else
      cd "$LOC_VAR"
    fi

    if [ ! -f "$LOC_CRC" ]; then
      echo "Settings CRC failed [crc file does not exists]"
      exit $ERR_CRYPTSETUP_MOUNT_CRC
    fi

    out=$( sha256sum -c "$LOC_CRC" | grep "FAILED" )
    echo "$(pwd)" > /tmp/checksum.log
    echo "$out"  >> /tmp/checksum.log

    cd -
    if [ ! "$out" == "" ]; then
      echo "Settings CRC FAILED"
      exit $ERR_CRYPTSETUP_MOUNT_CRC
    fi
}

function checkOutput() {
    if [ "$3" == "" ]; then
        out=`          eval "$1" 2>&1`
    else
        out=`echo $3 | eval "$1" 2>&1`
    fi
    if [ "$?" -ne 0 ]; then
        echo $out
        exit $2
    fi
}

function unmount_luks_partition()
{
    checkOutput "sudo umount               $LOC_VAR          " $ERR_CRYPTSETUP_UMOUNT
    checkOutput "sudo cryptsetup luksClose $LOC_DIR          " $ERR_CRYPTSETUP_CLOSE
}

function create_luks_partition()
{
    isMounted && unmount_luks_partition
    checkOutput "sudo mkdir      -p         $LOC_VAR         " $ERR_CRYPTSETUP_CREATE_MKDIR
    checkOutput "sudo cryptsetup luksFormat $LOC_DEV         " $ERR_CRYPTSETUP_CREATE_FORMAT    $PASSWORD
    checkOutput "sudo cryptsetup luksOpen   $LOC_DEV $LOC_DIR" $ERR_CRYPTSETUP_CREATE_OPEN      $PASSWORD
    checkOutput "sudo mkfs.ext4             $LOC_MAP         " $ERR_CRYPTSETUP_CREATE_MKFS
    checkOutput "sudo mount      -t ext4    $LOC_MAP $LOC_VAR" $ERR_CRYPTSETUP_CREATE_MOUNT
}

function mount_luks_partition()
{
    isEncrypted                         # if     encrypted  will continue else will exit with error
    isMounted                           # if     mounted    will echo and return 0=IS_MOUNTED
    if [ ! $? -eq $IS_MOUNTED ]; then   # if not mounted, mount it
        checkOutput "sudo cryptsetup luksOpen   $LOC_DEV $LOC_DIR" $ERR_CRYPTSETUP_MOUNT_OPEN   $PASSWORD
        checkOutput "sudo mount      -t ext4    $LOC_MAP $LOC_VAR" $ERR_CRYPTSETUP_MOUNT_MOUNT
    fi
    checkShaSum                         # if checksum fails echos and exits
}

function handleCommand() {
    # Handle the first argument to script, one of start, stop, erase, restart, force-reload or status
    case $1 in
    setup)
        checkPassword
        create_luks_partition
        ;;

    mount)
        checkPassword
        mount_luks_partition
        ;;

    umount)
        unmount_luks_partition
        ;;

    *)
        echo "unknown command"
        exit $ERR_CRYPTSETUP_UNKNOWN
        ;;

    esac
}

handleCommand $1 $2

exit 0