dotfiles/root/etc/initcpio/hooks/lukskeyfile

#!/bin/ash

run_hook() {
    if [ -n "$lukskeyfile" ]; then
        # This is a needed kernel parameter for this hook
        modprobe -a -q loop dm-crypt >/dev/null 2>&1
        # Refer to help from `mkinitcpio -H lukskeyfile`.
        IFS=: read rootKeyDev rootKey cryptkeyLoc <<EOF
$lukskeyfile
EOF

        if [ -z "${cryptkeyLoc}" ]; then
            cryptkeyLoc=/crypto_keyfile.bin
        fi

        if resoleved=$(resolve_device "${rootKeyDev}" $rootdelay); then
            if mount -o noatime "${rootKeyDev}" /mnt>/dev/null 2>&1; then
                cat "/mnt/${rootKey}" > "${cryptkeyLoc}"
            else
                echo "Failed to mount ${rootKeyDev} on /mnt"
                /bin/sh
            fi
        else
            echo "Failed to find ${rootKeyDev} containing LUKS root key."
        fi
    fi
}