From: "H. Peter Anvin" <hpa@zytor.com>
To: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
akpm@linux-foundation.org, viro@zeniv.linux.org.uk,
drepper@gmail.com, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] nextfd(2)
Date: Wed, 11 Apr 2012 12:49:25 -0700 [thread overview]
Message-ID: <4F85E045.9070706@zytor.com> (raw)
In-Reply-To: <CAHGf_=qBY1uVqWiDoOQY5UrxqK8G47+J_o=HQAbutGZNdhX5Ug@mail.gmail.com>
On 04/11/2012 12:46 PM, KOSAKI Motohiro wrote:
>>
>> a) inherently racy in a multithreaded environment;
>
> I would say two things. 1) I know and I agree we _can_ misuse the interface.
> but many already existed interface also can be misused. 2) As I
> already explained
> this can be used correctly.
>
> So, I have a question. Why do you bother a possibility of misuse? Of
> if you didn't point out misuse, can you please point out a real world
> use case of multi threads + fd interation?
>
This were brought up in the POSIX discussion as part of why these
interfaces were considered undesirable.
>
>> b) unsafe because there might be file descriptors used by libc itself.
>
> I agree this. Even though almost developer don't use libc message catalogue and
> we can avoid such issue by using nextfd() + fcntl(O_CLOEXEC).
>
No, that's exactly the point that we cannot.
>
> Yeah, I don't think fdwalk() is problematic. It's an option if I
> understand Alexey's mail
> correctly. but I disagree almost all developers should fix a design
> and rewrite their
> applications. In theory, they can avoid glibc or they can rewrite all
> of their code or
> avoid linux. but there is one problem. unrealistic.
>
The problem -- as was brought up in the POSIX discussion -- is that you
actually end up breaking *properly functioning programs*.
-hpa
next prev parent reply other threads:[~2012-04-11 19:49 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-01 12:57 [PATCH] nextfd(2) Alexey Dobriyan
2012-04-01 13:58 ` Konstantin Khlebnikov
2012-04-01 21:30 ` Alexey Dobriyan
2012-04-02 0:09 ` Alan Cox
2012-04-02 8:38 ` Konstantin Khlebnikov
2012-04-02 9:26 ` Cyrill Gorcunov
2012-04-01 15:43 ` Eric Dumazet
2012-04-01 21:31 ` Alexey Dobriyan
2012-04-01 21:36 ` Alan Cox
2012-04-01 17:20 ` Linus Torvalds
2012-04-01 18:28 ` Valentin Nechayev
2012-04-01 21:33 ` Alexey Dobriyan
2012-04-01 19:21 ` Arnd Bergmann
2012-04-01 21:35 ` Alexey Dobriyan
2012-04-01 22:05 ` H. Peter Anvin
2012-04-04 12:13 ` Arnd Bergmann
2012-04-01 22:03 ` H. Peter Anvin
2012-04-01 22:13 ` H. Peter Anvin
2012-04-02 0:08 ` Alan Cox
2012-04-30 9:58 ` Valentin Nechayev
2012-04-02 1:19 ` Kyle Moffett
2012-04-02 1:37 ` H. Peter Anvin
2012-04-02 11:37 ` Ulrich Drepper
2012-04-06 9:54 ` Alexey Dobriyan
2012-04-06 15:27 ` Colin Walters
2012-04-06 16:14 ` H. Peter Anvin
2012-04-06 20:16 ` Alexey Dobriyan
2012-04-06 20:33 ` H. Peter Anvin
2012-04-06 21:02 ` H. Peter Anvin
2012-04-12 10:54 ` Alexey Dobriyan
2012-04-12 11:11 ` Alan Cox
2012-04-12 13:35 ` Alexey Dobriyan
2012-04-12 13:51 ` H. Peter Anvin
2012-04-12 19:21 ` Alexey Dobriyan
2012-04-12 14:09 ` Eric Dumazet
2012-04-06 16:23 ` H. Peter Anvin
2012-04-07 21:21 ` Ben Pfaff
2012-04-11 0:12 ` KOSAKI Motohiro
2012-04-11 0:09 ` KOSAKI Motohiro
2012-04-11 17:58 ` H. Peter Anvin
2012-04-11 18:04 ` Linus Torvalds
2012-04-11 18:11 ` H. Peter Anvin
2012-04-11 19:46 ` KOSAKI Motohiro
2012-04-11 19:49 ` H. Peter Anvin [this message]
2012-04-11 20:23 ` KOSAKI Motohiro
2012-04-11 20:32 ` H. Peter Anvin
2012-04-17 18:12 ` KOSAKI Motohiro
2012-04-11 18:00 ` H. Peter Anvin
2012-04-11 19:20 ` KOSAKI Motohiro
2012-04-11 19:22 ` H. Peter Anvin
2012-04-11 19:26 ` KOSAKI Motohiro
2012-04-11 19:28 ` H. Peter Anvin
2012-04-11 19:31 ` KOSAKI Motohiro
2012-04-11 19:32 ` H. Peter Anvin
2012-04-02 23:17 ` KOSAKI Motohiro
2012-04-02 23:56 ` H. Peter Anvin
2012-04-04 11:51 ` Ulrich Drepper
2012-04-04 16:38 ` KOSAKI Motohiro
2012-04-04 16:43 ` Ulrich Drepper
2012-04-04 17:07 ` KOSAKI Motohiro
2012-04-04 17:49 ` Ulrich Drepper
2012-04-04 18:08 ` KOSAKI Motohiro
2012-04-04 16:31 ` KOSAKI Motohiro
2012-04-04 17:10 ` Colin Walters
2012-04-04 17:25 ` Colin Walters
2012-04-04 23:35 ` KOSAKI Motohiro
2012-04-04 18:44 ` H. Peter Anvin
2012-04-03 19:21 ` Colin Walters
2012-04-04 3:01 ` Al Viro
2012-04-04 17:10 ` KOSAKI Motohiro
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