WIP: fix: dune_digest: don't open with Unix module

src/dune_digest/dune_digest.ml

@@ -17,14 +17,12 @@ end
 
 module Direct_impl : Digest_impl = struct
   let file file =
-    let fd =
-      match Unix.openfile file [ Unix.O_RDONLY ] 0 with
-      | fd -> fd
-      | exception Unix.Unix_error (Unix.EACCES, _, _) ->
-        raise (Sys_error (sprintf "%s: Permission denied" file))
-      | exception exn -> reraise exn
-    in
-    Exn.protectx fd ~f:md5_fd ~finally:Unix.close
+    let ic = Stdlib.open_in_bin file in
+    Exn.protect
+      ~f:(fun () ->
+        let fd = Unix.descr_of_in_channel ic in
+        md5_fd fd)
+      ~finally:(fun () -> Stdlib.close_in_noerr ic)
 
   let string = D.string
 end