Date: Tue, 18 Apr 2023 18:21:48 +0200
To: Bruno Haible <bruno@clisp.org>
Subject: Re: renameat2 works differently than on Linux
Message-ID: <ZD7DnCdknznSO5pq@calimero.vinschen.de>
Mail-Followup-To: Bruno Haible <bruno@clisp.org>, cygwin@cygwin.com
References: <1745205.A0I09U8b9p@nimes>
MIME-Version: 1.0
Content-Disposition: inline
In-Reply-To: <1745205.A0I09U8b9p@nimes>
Precedence: list
From: Corinna Vinschen via Cygwin <cygwin@cygwin.com>
Reply-To: cygwin@cygwin.com
Cc: Corinna Vinschen <corinna-cygwin@cygwin.com>, cygwin@cygwin.com
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Errors-To: cygwin-bounces+archive-cygwin=delorie.com@cygwin.com
Sender: "Cygwin" <cygwin-bounces+archive-cygwin=delorie.com@cygwin.com>

Hi Bruno,

On Apr 18 14:47, Bruno Haible via Cygwin wrote:
> Hi,
> 
> The renameat2 function is "Linux-specific", says the man page [1]; however,
> Cygwin implements it as well.
> 
> In Cygwin 3.4.6, in a specific case, it operates differently than the
> Linux function. Namely, if the old* arguments and the new* arguments
> are the same and the flag RENAME_NOREPLACE is specified.
> [...]
> Output on Linux (glibc, musl libc):
> ret=-1, errno=17=EEXIST
> 
> Output on Cygwin 3.4.6:
> ret=0
> 
> Note that there is some ambiguity about this case in [1]: One one hand,
> there is the general statement about rename():
>   "If oldpath and newpath are existing hard links referring to the
>    same file, then rename() does nothing, and returns a success status."
> On the other hand, the text regarding RENAME_NOREPLACE says:
>   "Return an error if newpath already exists."

Thanks for the testcase.  I guess the ambiguity doesn't matter, given
it's a Linux function anyway.  It makes sense to behave the same, if
possible.

I pushed a patch.  The next test release cygwin-3.5.0-0.284.gd30a5917a9c4
will contain the patch for testing.


Thanks,
Corinna

-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple