Smartly mount the encrypted disk after unlocking the device

crypt_mount.sh

#!/bin/bash

DEMOUNT=0
SETUP=0
NEW=0


while getopts "dsnh" flag; do
    case $flag in
        d|demount) DEMOUNT=1;;
        s|setup) SETUP=1;;
        n|new) NEW=1;;
        h|help) echo "usage: $(basename $0)
            -d (demount) DEMOUNT (switch to unmount instead of mount)
            -s (setup) do guided setup of luks mount
            -n (new) wipe and create crypt; implies 'setup'
            -h (help)";
                exit 0;;
    :) error "option -$lastflag requires an argument";;
  esac
  lastflag="$flag"
  shift $((OPTIND - 1)); OPTIND=1
done
sudo -v

write_and_output() {
    line="$1"
    file="$2"
    if grep -q "$line" "$file" 2>/dev/null; then
        echo " >> Already written"
        return
    fi
    echo -n ' >> '
    echo -e "# Generated via crypt_mount" | sudo tee -a "$file" > /dev/null
    echo "$line" | sudo tee -a "$file"
}

mount="$1"

if [ $SETUP -eq 1 ] || [ $NEW -eq 1 ]; then
    read -p "Tag: " mapper_name
    read -p "Device: " disk
    read -p "Mount [/media/$mapper_name] :" mount
    sudo -v
    echo
    [ -z "$mount" ] && mount="/media/$mapper_name"
    echo "Creating fstab entry:"
    write_and_output "/dev/mapper/$mapper_name $mount ext4 defaults,noauto 0 2" /etc/fstab
    [ ! -d "$mount" ] && { echo "Creating mountpoint"; sudo mkdir -p "$mount"; }
    echo "Creating crypttab entry:"
    write_and_output "$mapper_name $disk none default,luks,noauto" /etc/crypttab
    if [ $NEW -eq 1 ]; then
        sudo cryptsetup -y -v luksFormat "$disk"
        sudo cryptsetup luksOpen "$disk" "$mapper_name"
        sudo mkfs.ext4 /dev/mapper/$mapper_name
    fi
fi

mount="${mount%/}"
echo "mount: $mount"

if [[ "$mount" =~ ^/* ]] && grep -q "$mount" /etc/fstab; then
    mapper_name="$(cat /etc/fstab | grep "$mount" | cut -d '/' -f 4 |
        while read foo; do
            if grep -q "$foo" /etc/crypttab; then echo $foo
            else echo "Warning: skipping $foo" >&2
            fi; done | xargs)"
    echo mapper_name: $mapper_name
    if [ -z "$mapper_name" ]; then
        echo "Nothing to do"
        exit 0;
    fi

    # Check if it's luks, or "regular"
    if cat /etc/crypttab | grep "$mapper_name" | grep -vP "^#" | grep -q "luks"; then
        disk=$(grep "$mapper_name" /etc/crypttab | grep -vP "^#" | head -1 | awk '{print $2}')
        decrypt_command="sudo cryptsetup luksOpen $disk $mapper_name"
        encrypt_command="sudo cryptsetup luksClose $mapper_name"
    else
        decrypt_command="sudo cryptdisks_start $mapper_name"
        encrypt_command="sudo cryptdisks_stop $mapper_name"
    fi
    echo "$encrypt_command"
    echo "$decrypt_command"

    if [ $DEMOUNT -eq 1 ]; then
        # just close
        sudo umount /dev/mapper/$mapper_name; sync; sleep 1
        sudo fsck -fy /dev/mapper/$mapper_name; sync; sleep 1
        $encrypt_command
    else
        # try to decrypt and then mount, If it fails, close the device
        $decrypt_command &&  ( sudo mount $mount || $encrypt_command )
    fi
else
    echo "invalid path"
fi