daemon: inspect: Resolve Ubuntu 22+ /dev/disk/by-uuid/ in fstab

Ubuntu 22= uses /dev/disk/by-uuid/ followed by a filesystem UUID in
fstab entries.  Resolve these to mountables.

A typical fstab entry looks like this:

  # /boot was on /dev/vda2 during curtin installation
  /dev/disk/by-uuid/b4e56462-5a64-4272-b76d-f5e58bd8f128 /boot ext4 defaults 0 1

The comment is generated by the installer and appears in the fstab.
This entry would be translated to /dev/sda2.

(cherry picked from commit 7a1ffd744b)
(cherry picked from commit 0d466cb25e)

daemon/inspect_fs_unix_fstab.ml

@@ -394,6 +394,19 @@ and resolve_fstab_device spec md_map os_type =
     resolve_diskbyid part default
   )
 
+  (* Ubuntu 22+ uses /dev/disk/by-uuid/ followed by a UUID. *)
+  else if String.is_prefix spec "/dev/disk/by-uuid/" then (
+    debug_matching "diskbyuuid";
+    let uuid = String.sub spec 18 (String.length spec - 18) in
+    try
+      (* Try a filesystem UUID.  Unclear if this could be a partition UUID
+       * as well, but in the Ubuntu guest I tried it was an fs UUID XXX.
+       *)
+      Mountable.of_device (Findfs.findfs_uuid uuid)
+    with
+      Failure _ -> default
+  )
+
   else if PCRE.matches re_freebsd_gpt spec then (
     debug_matching "FreeBSD GPT";
     (* group 1 (type) is not used *)