From: Ken Brown <kbrown@cornell.edu>
To: cygwin-patches@cygwin.com
Subject: Re: [PATCH] Cygwin: fchmodat: add limited support for AT_SYMLINK_NOFOLLOW
Date: Wed, 27 Jan 2021 08:22:53 -0500 [thread overview]
Message-ID: <5b3fbee6-b80f-1a46-4574-059b9b0c951f@cornell.edu> (raw)
In-Reply-To: <20210127124054.GT4393@calimero.vinschen.de>
On 1/27/2021 7:40 AM, Corinna Vinschen via Cygwin-patches wrote:
> On Jan 26 16:30, Ken Brown via Cygwin-patches wrote:
>> Allow fchmodat with the AT_SYMLINK_NOFOLLOW flag to succeed on
>> non-symlinks. Previously it always failed, as it does on Linux. But
>> POSIX permits it to succeed on non-symlinks even if it fails on
>> symlinks.
>>
>> The reason for following POSIX rather than Linux is to make gnulib
>> report that fchmodat works on Cygwin. This improves the efficiency of
>> packages like GNU tar that use gnulib's fchmodat module. Previously
>> such packages would use a gnulib replacement for fchmodat on Cygwin.
>
> Wait, what? So if Cygwin behaves like Linux, gnulib treats fchmodat
> as non-working? So what does gnulib do on a Linux system? Does it
> use its own fchmodat there, too?
Apparently so. Here's a comment from gnulib's test program for fchmodat:
/* Test whether fchmodat+AT_SYMLINK_NOFOLLOW works on non-symlinks.
This test fails on GNU/Linux with glibc 2.31 (but not on
GNU/kFreeBSD nor GNU/Hurd) and Cygwin 2.9. */
I agree that it's strange.
Ken
next prev parent reply other threads:[~2021-01-27 13:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-26 21:30 Ken Brown
2021-01-27 12:16 ` Ken Brown
2021-01-27 12:40 ` Corinna Vinschen
2021-01-27 13:22 ` Ken Brown [this message]
2021-01-27 13:27 ` Corinna Vinschen
2021-01-27 17:26 ` Ken Brown
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