X-Recipient: archive-cygwin AT delorie DOT com
X-Original-To: cygwin AT cygwin DOT com
Delivered-To: cygwin AT cygwin DOT com
DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org B0732385700C
Authentication-Results: sourceware.org;
 dmarc=none (p=none dis=none) header.from=emmenlauer.de
Authentication-Results: sourceware.org;
 spf=fail smtp.mailfrom=mario AT emmenlauer DOT de
To: cygwin AT cygwin DOT com
References: <d05f79db-5574-d408-28ce-7840cddff7ec AT emmenlauer DOT de>
 <1279009444 DOT 20201006184606 AT yandex DOT ru>
From: Mario Emmenlauer <mario AT emmenlauer DOT de>
X-Tagtoolbar-Keys: D20201006181055240
Message-ID: <c5adbabd-f6c1-7a09-2af2-fdd819b76cdf@emmenlauer.de>
Date: Tue, 6 Oct 2020 18:10:55 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.10.0
MIME-Version: 1.0
In-Reply-To: <1279009444.20201006184606@yandex.ru>
Content-Language: en-GB
X-SA-Exim-Connect-IP: 213.160.25.97
X-SA-Exim-Mail-From: mario AT emmenlauer DOT de
X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on
 server2.sourceware.org
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS,
 NICE_REPLY_A, SPF_HELO_NONE, TXREP,
 T_SPF_PERMERROR autolearn=ham autolearn_force=no version=3.4.2
Subject: Re: test -r or -x always return false on an NFS mount?
X-SA-Exim-Version: 4.2.1 (built Sun, 08 Nov 2009 07:31:22 +0000)
X-SA-Exim-Scanned: Yes (on aldebaran.he1ix.org)
X-BeenThere: cygwin AT cygwin DOT com
X-Mailman-Version: 2.1.29
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>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Errors-To: cygwin-bounces AT cygwin DOT com
Sender: "Cygwin" <cygwin-bounces AT cygwin DOT com>


Dear Andrey,

On 06.10.20 17:46, Andrey Repin wrote:
> Greetings, Mario Emmenlauer!
> 
>> thanks for the awesome Cygwin, its really great!
> 
>> Everything seems to work quite well, and in `ls -la` I can see the
>> file permissions and user and group entries. But when using `test`
>> to check for read (`test -r`) or execute permissions (`test -x`), it
>> always returns false, even for readable files. `ls` on the other hand
>> shows the permissions correctly, and `cat`ing the files works without
>> problems.
> 
> This is a known issue. For years known.
> test only guess -r/-w/-x results based on permissions as it sees them.
> But it do not actually try to read/write/execute the subject, which, as you
> can imagine, may lead to all sorts of false positives/negatives on filesystems
> with less than trivial access control setups.
> In other words, don't test for rwx if you can avoid it. The results MAY be
> wrong.


Ok, this explains a lot, and I almost guessed as much! But can I ask,
do you happen to know why `ls -l` shows the "correct" permissions
including 'r' and 'x'? It seems `ls` has some magic that `test` is
lacking? And I can not imagine that `ls` would try to open every
file, or does it?.

So could this "magic" be ported from `ls` to `test`?

Cheers,

    Mario Emmenlauer

--
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