Race-condition ? (was: "Preserve owner and group" on MSDOS/Windows)

[Gaëtan LEURENT]

Juanma Barranquero wrote on 24 Jun 2005 11:08:20 +0200:

> 2005-06-23  Richard M. Stallman  <address@hidden>
>
>       * fileio.c (Frename_file): Preserve owner and group, if possible,
>       when copying.

This is done with a call to chown, and I think this is a source of
race-conditions, like the one that was recently discovered in bzip2
(someone could have replaced the file by a link to another file between
Fcopy_file and chown).

I believe we should use fchown instead.

In fileio.c there is also a call to chmod in copy-file which seem to
suffer the same problem. This one is also in emacs 21.4.

I think lisp calls to set-file-modes should also be checked carefully.

-- 
Gaëtan LEURENT