bug#865: 23.0.60; The directory is unsafe today

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: 865@emacsbugs.donarmstrong.com,  jasonr@gnu.org,  
> emacs-pretest-bug@gnu.org
> Date: Sat, 06 Sep 2008 23:43:52 -0400
> 
> > The MS-Windows access right set is richer than just Read,
> > Write, Execute.
> 
> That doesn't really matter, the point is that nobody but the creating
> user should have any right.

This is impossible on Windows, AFAIK.  There are special flags to the
syscall that opens a file or directory that can bypass any denied
rights to enter a directory or open a file.  (These flags allegedly
exist so that system backup and restore programs could DTRT without
running as a privileged user.)

So, if we are to emulate this special value of mode-bits on Windows,
we need to decide exactly what rights we need to deny.

Or maybe a better implementation for Windows would be to create
encrypted files.  Or maybe something else entirely; that's why I was
asking questions about the semantics of this.