cryptmount.sh

#!/bin/bash
MOUNTPOINT="/media/crypt"
CRYPTNAME="cryptroot"

set -euo pipefail

[[ $(id -u) -ne 0 ]] && {
	echo "This script must be run as root"
	exit 1
}

mounted=$(findmnt $MOUNTPOINT -oSOURCE | tail -n1) && {
    if device=$(cryptsetup status "$mounted" 2>/dev/null | grep device | xargs | cut -d' ' -f2) ; then
        echo -n "Encrypted device $device is mounted on $MOUNTPOINT. Close and umount? [y/n] "
        read answer
        if [ "$answer" = "y" ]; then
            umount "$MOUNTPOINT"
            cryptsetup close "$mounted"
        else
            exit 0
        fi
    else
        echo "Non-LUKS device $mounted is mounted on $MOUNTPOINT. Unmount it manually and try again."
        exit 1
    fi
}

[[ $# -ne 1 ]] && exit 0

cryptsetup status "$CRYPTNAME" &>/dev/null && {
    echo -n "Cryptsetup device '$CRYPTNAME' exists. Close and unmount? [y/n] "
    read answer
    if [ "$answer" = "y" ]; then
        mpoint=$(findmnt /dev/mapper/cryptroot -oTARGET | tail -n1) && umount $mpoint
        cryptsetup close "$CRYPTNAME"
    else
        exit 1
    fi
}

cryptsetup open "$1" "$CRYPTNAME"
mount "/dev/mapper/$CRYPTNAME" "$MOUNTPOINT"
echo "Done!"

# vim:ft=sh