bug#10257: 23.3.1 Cygwin: network drives - file is write protected (false positive)

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 13 Dec 2011 16:00:42 +0200
> From: jari <jari.aalto@cante.net>
> Cc: 10257@debbugs.gnu.org
> 
> | So why don't you ask on the Cygwin list whether access() and
> | euidaccess() can be taught to give the "right" answer for files on
> | such drives.  Or maybe the question is simply whether Cygwin can be
> | taught to determine the correct UID.
> 
> Sure, but because The network drive is not part of Windows Domain, I'm
> afraid Cygwin has any means to determine what the correct UID or GID
> would be are as they have no correspondence on the Windows side.

??? As long as the network drive is mounted using Windows APIs (which
must be the case), the NT security features should be fully supported
for it.  That includes the user and group IDs of every file.  So why
does Cygwin's `stat' return 4294967295 (which AFAIU is a fancy way of
saying -1) for UID and GID of these files?

> In any case, this is a big problem in daily use; especially because
> the file system check cannot be ignored, bypassed or configured to
> "just to go ahead and write without questions".

We don't want to put some ad-hoc "solution" into Emacs just because it
is urgent for you.  We want to understand the problem, and in
particular figure out whether it is an Emacs problem or a problem with
the Cygwin implementation of some library function.  Only then it will
be possible to establish what is the best solution.

Ken repeatedly suggested that you ask on the Cygwin list about this.
I think this is a good idea, as people here (with the exception of
Ken) know very little about Cygwin internals.

In any case, if you don't wish to follow Ken's advice, but want to
solve this urgent problem, you have the sources, don't you?