From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <corinna-cygwin@cygwin.com>
Received: from mout.kundenserver.de (mout.kundenserver.de [212.227.126.134])
	by sourceware.org (Postfix) with ESMTPS id 1593D3858D1E
	for <cygwin@cygwin.com>; Wed, 21 Dec 2022 11:31:43 +0000 (GMT)
Authentication-Results: sourceware.org; dmarc=permerror header.from=cygwin.com
Authentication-Results: sourceware.org; spf=fail smtp.mailfrom=cygwin.com
Received: from calimero.vinschen.de ([24.134.7.25]) by
 mrelayeu.kundenserver.de (mreue010 [212.227.15.167]) with ESMTPSA (Nemesis)
 id 1N3KgE-1oglTA3CWA-010Nqs for <cygwin@cygwin.com>; Wed, 21 Dec 2022
 12:31:42 +0100
Received: by calimero.vinschen.de (Postfix, from userid 500)
	id C1D45A8078A; Wed, 21 Dec 2022 12:31:41 +0100 (CET)
Date: Wed, 21 Dec 2022 12:31:41 +0100
From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: open /dev/null O_NOFOLLOW fails with ELOOP
Message-ID: <Y6LunfrlJ1767ND5@calimero.vinschen.de>
Reply-To: cygwin@cygwin.com
Mail-Followup-To: cygwin@cygwin.com
References: <Y6Lqz3O1AcAPjBRu@xps13>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <Y6Lqz3O1AcAPjBRu@xps13>
X-Provags-ID: V03:K1:UlG9vGeNVpoG7M58CrY2UA8bmizoVBBzbq4ZlWeZ2HF3VokDkxF
 hZf2rsgkvB7aXAf7SLRMXJvWKA7NtyQd3lenC9EvaeAiAuLvz4PYDfwHIThBi9t/tQgrzL1
 t2iFfJiCpVexHgrEYb26+V5ZJJ/4sL2QehZ2liXL4FmjhBQ6FSV8C7lAjv/4O6c7jWpnZrJ
 y92wDOEr9OScyu13kzbcA==
UI-OutboundReport: notjunk:1;M01:P0:C9d2d07wrR4=;LqKEZYyJKLMJraWnRtFuMqgdSSl
 iAxULPw7Da+wk0nA7ICvaryoWRfxYlwDy/cWzAk1phm67Xt2qcw0QbVjgiAs1HqfIrJJd7lKS
 PWKPAuQqKpxCu/rWDgP8h6u/2klAkioImcShpNa7pq9OoAHhNBcWVbgYXsWISlYxOBJ5JaV66
 b93wJzoIGWyn8n5Xm9e02yks3H/4NXAV14zQsiCABJtkoxw0yCEt7PDBhqndrkC6dDfjDtrWd
 bkCZi7d51G+ldWMTtghyi6J6Gxzwy64ZOFVO3a62AcJ7qWdUbERU5JFBCZhyLfxTVdYraz6g2
 G3RlIxorXUB182S+kjHElYJ6Sq23SHrxhQt1XoVliQJfEO7Nxpy06aho0DWqDzzpqklhiij/Y
 RmJYui0TzPrMuqOJqAvkXxKGsKRhYw0/inDTZWrHnaPf1cvyJ7llI4T5vaFywFF8miKQ5ma3v
 GcxF3r1pzviNA1nIECJYRMW/ZqpK233Hm5XQ6+Pgtqd0P3U6hzVH+34UZqG0E3zcJuLNlwh69
 CxqBGIP4NztYGJ3LDQp+6/geeQncXrDWRn6F5qX20BF1b3p3nt2GLJk/3BaFF+/OgEbv9EfMo
 nllLdb7nyULaEgnDzwTbJAAC3Y1Rc5Sw3JK5OEmRmFU4NxWtA2ZGQf9np2wdxyS0BBGc1My8y
 PUSvphRZ0afuoMvCEARwma70jwuHYuhF0R6ZdQGFzw==
X-Spam-Status: No, score=-96.6 required=5.0 tests=BAYES_00,GOOD_FROM_CORINNA_CYGWIN,KAM_DMARC_STATUS,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_FAIL,SPF_HELO_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org
List-Id: <cygwin.cygwin.com>

Hi Glenn,

On Dec 21 06:15, gs-cygwin.com--- via Cygwin wrote:
> open /dev/null O_NOFOLLOW fails with ELOOP
> 
> Windows 10, 64-bit cygwin
> 
> Failed with my existing install, then I ran setup.exe, updated to
> latest, and my tests still failed.
> 
> a.c
> ---
> 
> #include <sys/types.h>
> #include <fcntl.h>
> #include <stdio.h>
> 
> int main (void)
> {
>     int fd = open("/dev/null", O_RDWR | O_NOFOLLOW, 0);
>     if (fd < 0)
>         perror("open(/dev/null)");
>     return fd;
> }
> 
> 
> $ gcc a.c ; ./a.exe
> open(/dev/null): Too many levels of symbolic links
> 
> While troubleshooting this, there were times where it succeeded and then
> times where it failed, though it failed most of the time.  It did not
> fail (or succeed) randomly, but seemingly in streaks.
> 
> Trying to start lighttpd seems to run into this bug reliably,
>   $ /usr/sbin/lighttpd -D -f /etc/lighttpd/lighttpd.conf
> In the next release of lighttpd, I may end up omitting O_NOFOLLOW
> if __CYGWIN__ is defined.

Thanks for the report.  I think I see what's going on, stay tuned.


Thanks,
Corinna