DMARC-Filter: OpenDMARC Filter v1.4.2 delorie.com 5378o1fL1339058
Authentication-Results: delorie.com; dmarc=pass (p=none dis=none) header.from=cygwin.com
Authentication-Results: delorie.com; spf=pass smtp.mailfrom=cygwin.com
DKIM-Filter: OpenDKIM Filter v2.11.0 delorie.com 5378o1fL1339058
Authentication-Results: delorie.com;
	dkim=pass (1024-bit key, unprotected) header.d=cygwin.com header.i=@cygwin.com header.a=rsa-sha256 header.s=default header.b=LJZrwfM0
X-Recipient: archive-cygwin AT delorie DOT com
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 5F9C4384D19E
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com;
	s=default; t=1744015799;
	bh=rmwYSyzBKW22VN4iBIwZEOK8sB7+0QbzoAvW0Ak2XD8=;
	h=Date:Subject:To:References:In-Reply-To:List-Id:List-Unsubscribe:
	 List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:
	 From;
	b=LJZrwfM0o8PH+UZz20xCg/E5ALGp/EalUNdb4feAbWrq+pqSFX5mEDzn6SAVVgupm
	 IjyVhqP+C/HWsAHT0leiX7N+wpsdGo+RoJMDpIE0xkh2wKDMrRDHvE0FpWAp5COtJE
	 Q5H/7OcoAod0mTR03VQPNFVAbVOGWbModJxTGiN4=
X-Original-To: cygwin AT cygwin DOT com
Delivered-To: cygwin AT cygwin DOT com
DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org A9228384D196
ARC-Filter: OpenARC Filter v1.0.0 sourceware.org A9228384D196
ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1744015772; cv=none;
 b=k1GOCRHsAt08ZJJwcWepZ8YFM4Pv06obDlFZZScileAIjAF/sdr80Y8O0P6HE/Q8lfysj3/CfMzORkHwqslG8LP4y8cjMW1ZpajvYkPmTubgm0hHTCZMR6UTtY7BU337Fq8dfexJsj4roXkDg9Ifqunh3DOqNNf7t+Kkk/5Ujqc=
ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key;
 t=1744015772; c=relaxed/simple;
 bh=Hk9ttA8kvgNpTvJpmKqw1WQHSUaSDcZYOxZZs9svnOA=;
 h=DKIM-Signature:Message-ID:Date:MIME-Version:Subject:To:From;
 b=Sj1OrtotOt6UFXQuHFXEq2iHSVabKMOiQo8gNZ2Jmlweib6o+uOpHz3GsG9ZJfyjhF70q35h+Gx/hNfJvB4M0aIVBTuekpGQKYT1bYo+08g2tmTLmLJ17PrOIizTJjGfaZxIFmwFVOXVYZM0v+MLC8VF+V5RzfBNhdlsyw97K98=
ARC-Authentication-Results: i=1; server2.sourceware.org
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A9228384D196
DKIM-Filter: OpenDKIM Filter v2.10.3 mail.cs.ucla.edu BB42B3C010870
X-Virus-Scanned: amavis at mail.cs.ucla.edu
Message-ID: <616e0b6d-e1eb-4533-b1cd-1922a33b4ba1@cs.ucla.edu>
Date: Mon, 7 Apr 2025 01:49:31 -0700
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: symbolic link curiousity in 3.6.0
To: =?UTF-8?Q?P=C3=A1draig_Brady?= <P AT draigbrady DOT com>,
        Bruno Haible <bruno AT clisp DOT org>, bug-gnulib AT gnu DOT org, cygwin AT cygwin DOT com,
        Coreutils <coreutils AT gnu DOT org>
References: <Pine DOT BSF DOT 4 DOT 63 DOT 2503250218240 DOT 74063 AT m0 DOT truegem DOT net>
 <Z-aGVCUo0N1VSl5s AT calimero DOT vinschen DOT de>
 <Z-aP1jhjXTUVvP-E AT calimero DOT vinschen DOT de> <11037686 DOT 3WhfQktd6Z AT nimes>
 <91c9d441-36e3-4dd5-b2ca-3cfd498d2260 AT draigBrady DOT com>
 <Z-fLulclFs13NfAm AT calimero DOT vinschen DOT de>
 <a78f800c-0463-4efb-b431-c2c244bd13c7 AT cs DOT ucla DOT edu>
 <Z-k-ALeeYtJx7SqL AT calimero DOT vinschen DOT de>
Content-Language: en-US
Organization: UCLA Computer Science Department
In-Reply-To: <Z-k-ALeeYtJx7SqL@calimero.vinschen.de>
X-BeenThere: cygwin AT cygwin DOT com
X-Mailman-Version: 2.1.30
Precedence: list
List-Id: General Cygwin discussions and problem reports <cygwin.cygwin.com>
List-Unsubscribe: <https://cygwin.com/mailman/options/cygwin>,
 <mailto:cygwin-request AT cygwin DOT com?subject=unsubscribe>
List-Archive: <https://cygwin.com/pipermail/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-request AT cygwin DOT com?subject=help>
List-Subscribe: <https://cygwin.com/mailman/listinfo/cygwin>,
 <mailto:cygwin-request AT cygwin DOT com?subject=subscribe>
From: Paul Eggert via Cygwin <cygwin AT cygwin DOT com>
Reply-To: Paul Eggert <eggert AT cs DOT ucla DOT edu>
Content-Transfer-Encoding: 7bit
Content-Type: text/plain; charset="us-ascii"; Format="flowed"
Errors-To: cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com
Sender: "Cygwin" <cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com>

On 2025-03-30 05:50, Corinna Vinschen wrote:

> The definition of O_PATH requires an additional
> 
>    #include <fcntl.h>

Thanks, I added that and installed the patch into Gnulib.


> However, assuming not only Cygwin is affected, shouldn't the patch
> rather use O_PATH if it's available, O_RDONLY if not?

I hope only Cygwin is affected. The only other platforms mentioned in 
the code that might also be affected are IRIX and Tru64, neither of 
which is supported these days. I don't think the code would work on a 
Linux kernel, as acl_get_fd doesn't work with O_PATH fds as I recall; 
however this code should never be compiled with Linux so it should be OK.

If we run into the problem on a non-Cygwin platform we can complicate 
the patch along the lines that you suggest. Any such complication would 
involve more than merely using O_RDONLY, though, as the code should work 
even on unreadable files.


>> -#    if HAVE_ACL_GET_LINK_NP /* FreeBSD, NetBSD >= 10 */
>> +#    if HAVE_ACL_GET_LINK_NP /* FreeBSD, NetBSD >= 10, Cygwin >= 2.5 */
> 
> Changing the comment is wrong, IMHO.  We're adding a local version of
> HAVE_ACL_GET_LINK_NP specificially because Cygwin (or, FWIW, any system
> only providing the POSIX.1e draft 17 function) does not provide
> acl_get_link_np, isn't it?

As far as I know only Cygwin has the problem.


> For Cygwin, I will add this function nevertheless, but it will only be
> available in some upcoming version, either 3.6.1 or 3.7.0.

It's funny that so many operating systems are adding an 
"acl_get_link_np" function to mean the same thing, when "_np" means "not 
portable". This API is badly designed but I guess we're stuck with it.


> In terms of coreutils, I think either ls(1) gobble_file() or
> file_has_aclinfo_cache() should still handle ENOENT from
> file_has_aclinfo() and not print any error message.

I'm not so sure about this, but one issue at a time.

-- 
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