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From: "fweimer at redhat dot com" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug libc/23960] [2.28 Regression]: New getdents{64} implementation breaks qemu-user
Date: Fri, 02 Oct 2020 09:46:51 +0000 [thread overview]
Message-ID: <bug-23960-131-eW7YCVFNDB@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-23960-131@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=23960
--- Comment #60 from Florian Weimer <fweimer at redhat dot com> ---
(In reply to Danny Milosavljevic from comment #59)
> It's impossible to store a 64 bit result into a 32 bit slot.
You can do something like that if you can maintain a translation table. The
kernel cannot do it due to the way the getdents64 system call works. glibc can
do it for telldir/seekdir (allocating table slots on demand), which are the
interfaces that are actually problematic.
> Please don't use SYS_getdents. Just please mandate LFS instead. This should have been done long (decades) ago.
LFS does not change the return type of telldir. So it does not fix the issue.
We need to maintain a translation table for telldir and seekdir in DIR. It can
be filled on demand, so that applications that do not call telldir are pretty
much unaffected. The only thing that is a bit tricky is that we have to
pre-allocate the slot during readdir because telldir must not fail.
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next prev parent reply other threads:[~2020-10-02 9:46 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-23960-131@http.sourceware.org/bugzilla/>
2019-05-01 20:33 ` chewi at gentoo dot org
2020-09-17 21:42 ` tg at mirbsd dot de
2020-10-02 8:54 ` danny.milo at gmail dot com
2020-10-02 9:36 ` danny.milo at gmail dot com
2020-10-02 9:46 ` fweimer at redhat dot com [this message]
2020-10-02 10:41 ` danny.milo at gmail dot com
2020-10-02 11:03 ` danny.milo at gmail dot com
2020-10-02 13:17 ` jrtc27 at jrtc27 dot com
2020-10-02 14:22 ` adhemerval.zanella at linaro dot org
2020-10-02 23:06 ` tg at mirbsd dot de
2020-10-03 13:54 ` fweimer at redhat dot com
2020-10-03 13:55 ` fweimer at redhat dot com
2021-08-24 11:48 ` glaubitz at physik dot fu-berlin.de
2022-05-15 20:53 ` glaubitz at physik dot fu-berlin.de
2022-05-16 12:06 ` adhemerval.zanella at linaro dot org
2022-05-16 20:11 ` glaubitz at physik dot fu-berlin.de
2022-05-16 20:15 ` adhemerval.zanella at linaro dot org
2022-05-17 4:39 ` sam at gentoo dot org
2022-12-06 15:50 ` glaubitz at physik dot fu-berlin.de
2023-01-13 4:52 ` deller at gmx dot de
2023-12-29 23:52 ` sam at gentoo dot org
2024-01-05 8:33 ` sam at gentoo dot org
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