DMARC-Filter:	OpenDMARC Filter v1.4.2 delorie.com 52VHT5Am1848872
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 52VHT5Am1848872
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=YeQAq5su
X-Recipient:	archive-cygwin AT delorie DOT com
DKIM-Filter:	OpenDKIM Filter v2.11.0 sourceware.org BE7153865C24
DKIM-Signature:	v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com;
	s=default; t=1743442143;
	bh=Tid8kXPh7W91S/0w+/0PICOT12lmGmN0GeBkAkdA2UU=;
	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=YeQAq5suITHUqjZMxGrP4zSNmqlufn+y1+CyAcYg+Nf+lUzIPI9XCsvYO1Y0qSVUu
	sXpxqZX4LDMh6CKhKsqAvwBzKBI3RsCx4GsncLpVlJMQ3AMxBCjVgSAJ8fhG2nqKf9
	GAlxrQ3iVtTFnv3eai21W+085p4384ODa+GylGzU=
X-Original-To:	cygwin AT cygwin DOT com
Delivered-To:	cygwin AT cygwin DOT com
DMARC-Filter:	OpenDMARC Filter v1.4.2 sourceware.org D046F385AC21
ARC-Filter:	OpenARC Filter v1.0.0 sourceware.org D046F385AC21
ARC-Seal:	i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1743442082; cv=none;
	b=mab74vXode8f6QDsjoa53q/cktKdaLxkLyblzLxK0z6URcciU14yjZSEyAAFBehD6P85o123BuJ4H0WH7a+WzYrHFuEWaBsPCEkPr01uRCWlGYwdbu5QBYHNXvv40h2Xi6DiR6DQVcg6FPU7ho4T1QTnRi9UF1ccwXkum1n6/4g=
ARC-Message-Signature:	i=1; a=rsa-sha256; d=sourceware.org; s=key;
	t=1743442082; c=relaxed/simple;
	bh=CywarPgI3FX6CDITqTf3rKOysTaVGvZU5czkST0tUpY=;
	h=DKIM-Signature:Message-ID:Date:MIME-Version:Subject:To:From;
	b=HvhrBBEKNQi7YpmC+2syvTXq0Xnyt7UJ6jyXEQBnSQYZK3xEqnwpUPpP5m0EKS7tnRovwbe+MFcQ5CvlSWC+xhJRMRczAFLLF3bokZpBv9CQjeu7PyLOBBC1EWfV4nYVntkhKQHSJXsBSYWMQhpFTGVlmbEYty1Miozli+janbI=
ARC-Authentication-Results:	i=1; server2.sourceware.org
DKIM-Filter:	OpenDKIM Filter v2.11.0 sourceware.org D046F385AC21
X-Google-DKIM-Signature:	v=1; a=rsa-sha256; c=relaxed/relaxed;
	d=1e100.net; s=20230601; t=1743442080; x=1744046880;
	h=content-transfer-encoding:in-reply-to:from:content-language
	:references:to:subject:user-agent:mime-version:date:message-id
	:sender:x-gm-message-state:from:to:cc:subject:date:message-id
	:reply-to;
	bh=2l6lz4qsYuPOOxMpZrgF8pNB4fIFqIvZNLq+hKxumm4=;
	b=cQx/V4gIemUs6SVVswyMVsHJcy4X0w2KdgkJpJMMrxr5wHM2L95vdyp/lLH4t9nsOI
	44gBQSYsiU4Pjb+RH8Zvzj7EdEqCO9+6R52er/mSCrIvoc61somWoGHuRTExV1rRcgvj
	xSJ5GUD6+9pYI20CapytCzGQsJYkQudsthMooWLNDkh671Y7hEk14ZyoizBAeEZ7AaK+
	Mzy8BBgyTJNradsFyy6eTpBhgsmtCqGBPuGaEUbpmsMdXyvlNjnGt4P+YLWlNx2V+Aci
	ngtcuKgLHtWsOv758yoJUfW7wsatMBeMChEj2WVdsP7x9FeViw2comtixG42PBw7KrUA
	CPGw==
X-Forwarded-Encrypted:	i=1;
	AJvYcCXTVo6Q1Zu3GhwYvDElM8bkhdivCSxGZdPXkvX6LFObExyWnhbhwERjEpYkEhkBmaMAuEKezoQ=@cygwin.com
X-Gm-Message-State:	AOJu0YzC1yGMGKKoFoOOCoaUNqmOPGe0lDmP70FtOGh1SpSCjq5bgjc9
	NcU0BZpbHYfGF5UZco8UR6v/64+VaDPsjaDzlZH4RDGZo5J7SITm
X-Gm-Gg:	ASbGncvVrmjJplbnonS5mpoNXpP4jd2P2VIKoE9BaO9yT07Nku4NhSuEtCUg2wv1nXx
	nuM1Flb98xfh7SUtnVWXU0+QXYYQkSzO35K25q9ZAtdihrDFWFGaKIpPi3lB0214txEt2z3BWA0
	48tWJLXGCCEB8xXPOzCd97OmyRLXTZ3YiSVpcDpYkD8gYDYxTnPoEXv04CD3Nhx1tDkArrheAaU
	ZQwd7FPC+yhE9ldDYUhxPlSGbeF9A5ByWMtjHogGirHlHvSwW5nWEAlvj/4R3ldgIZxwVEUIQj+
	U6Kcw6w75/1uDeCjyhoJAIxh8ejdGpEtU0c13LfQETy5J2TFKIpBrZX8wFM+kOaAafIe71VcLYZ
	/orCWa14NULrbrSi6r6ZLC5+c
X-Google-Smtp-Source:	AGHT+IHiW3xIdyJe554WOnywRUIiEvJTujg1dFWm3qMQoUAmbbKDzN1ZXk9tEatZ/VuIdfjwioqibg==
X-Received:	by 2002:a05:600c:8117:b0:43c:efed:732d with SMTP id
	5b1f17b1804b1-43e8e3cf858mr90801585e9.16.1743442080206;
	Mon, 31 Mar 2025 10:28:00 -0700 (PDT)
Message-ID:	<cf5a19db-0985-4f0c-887a-5eb0f7a126b4@draigBrady.com>
Date:	Mon, 31 Mar 2025 18:27:58 +0100
MIME-Version:	1.0
User-Agent:	Mozilla Thunderbird Beta
Subject:	Re: symbolic link curiousity in 3.6.0
To:	Paul Eggert <eggert AT cs DOT ucla DOT edu>, 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>
	<1c0fb53a-2a6d-4d9d-8dbe-d70cc9296d5d AT draigBrady DOT com>
	<37f0f8b7-4251-4acd-b448-2f0d7c30a988 AT cs DOT ucla DOT edu>
In-Reply-To:	<37f0f8b7-4251-4acd-b448-2f0d7c30a988@cs.ucla.edu>
X-BeenThere:	cygwin AT cygwin DOT com
X-Mailman-Version:	2.1.30
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:	=?utf-8?q?P=C3=A1draig_Brady_via_Cygwin?= <cygwin AT cygwin DOT com>
Reply-To:	=?UTF-8?Q?P=C3=A1draig_Brady?= <P AT draigBrady DOT com>
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>
X-MIME-Autoconverted:	from base64 to 8bit by delorie.com id 52VHT5Am1848872

On 31/03/2025 17:32, Paul Eggert wrote:
> On 2025-03-30 07:26, Pádraig Brady wrote:
>> On 30/03/2025 13:50, Corinna Vinschen wrote:
>>> 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.  After all, due to
>>> the preconditions for building acl_get_link_np, we can't be sure
>>> acl_get_link_np has really been built into file-has-acl.c, and the
>>> problem persists.
>>
>> I tend to agree. I'll apply this later:
>>
>>
>> commit 88385a0d6d56197d3c180432c8a4bca07241e90b (HEAD -> master)
>> Author: Pádraig Brady <P AT draigBrady DOT com>
>> Date:   Sun Mar 30 15:16:54 2025 +0100
>>
>>       ls: suppress ENOENT errors when reading ACL info
>>
>>       * src/ls.c (gobble_file): Indicating unknown ACL info with '?'
>>       suffices for the edge case of a file being removed while reading,
>>       or older cygwin when reading through dangling symlinks.
>>       Reported by Corinna Vinschen.
> 
> Not sure this is a good idea, as a file being removed while getting its
> attributes indicates a serious issue that's worth bringing to the user's
> attention more directly.

I don't think this is a serious issue.
The file could be deleted at any time.
We're just suppressing errors in the edge case it's deleted
in the small window between the stat() and the acl_get_file().
We of course don't guarantee a file is present after we list it,
so we shouldn't jump through hoops for this edge case I think.

> How about if we instead use O_PATH on the file first, and then use fstat
> etc. on the result? That should fix the
> file-removed-while-getting-attributes situation, at least on platforms
> with /proc/self/fd (which I assume includes Cygnus). I realize that
> flistxattr etc. don't work on fds opened via O_PATH (why? this seems
> silly, but it's not my bailiwick) but /proc/self/fd works around that
> problem.

cheers,
Pádraig

-- 
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

- Raw text -