Add CLI helper for entropy volume

scripts/mount-entropy.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+# Unlock and mount Dankserver's encrypted entropy volume.
+#
+# The desktop flow uses the system's crypttab and fstab entries.  Reuse those
+# entries here instead of embedding a passphrase, mount options, or ownership
+# changes in this helper.  udisksctl reads the passphrase through its secure
+# desktop/terminal authentication path.
+set -euo pipefail
+
+MOUNTPOINT='/mnt/entropy'
+MAPPER='/dev/mapper/luks-cd86c728-459e-4f3a-bcc2-41ecf84685ec'
+
+if mountpoint -q "$MOUNTPOINT"; then
+    printf '%s is already mounted.\n' "$MOUNTPOINT"
+    exit 0
+fi
+
+if [ ! -e /dev/md0 ]; then
+    printf 'ERROR: RAID device /dev/md0 is not available.\n' >&2
+    exit 1
+fi
+
+if [ ! -e "$MAPPER" ]; then
+    udisksctl unlock --block-device /dev/md0
+fi
+
+# udisks2 may mount automatically as part of unlocking.  Do not attempt a
+# second mount in that case.
+if ! mountpoint -q "$MOUNTPOINT"; then
+    sudo mount "$MOUNTPOINT"
+fi
+printf 'Mounted %s.\n' "$MOUNTPOINT"