All of lore.kernel.org
 help / color / mirror / Atom feed
From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: Joshua Hudson <joshudson@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: [OT] 'volatile' in userspace
Date: Tue, 11 Jul 2006 21:53:53 +1000	[thread overview]
Message-ID: <44B39151.10600@yahoo.com.au> (raw)
In-Reply-To: <Pine.LNX.4.61.0607110945580.30961@yvahk01.tjqt.qr>

Jan Engelhardt wrote:
>>What's wrong with _exit(exec() == -1 ? 0 : errno);
>>and picking up the status with wait(2) ?
>>
> 
> The exec'd application may return regular error codes, which would 
> interfere. IIRC /usr/sbin/useradd has different exit codes depending on 
> what failed (providing some option, failure to create account, failure to 
> create home dir, etc.). Now if you exit(errno) instead, you have an 
> overlap.

You're right. Maybe you could return -ve or with a high bit set,
but I guess you may not know what the app will return.

But I don't see how the volatile or pipe solutions are any better
though: it would seem that both result in undefined behaviour
according to my vfork man page. At least the wait() solution is
defined (and workable, if you know what the target might return).

> And your code is somewhat wrong. Given that exec() would stand for 
> execve(someprogram_and_args_here), if it returned -1 you would return 0, 
> indicating success. Can't be. And if exec() does not return -1, which it 
> never should, you return errno, which never reaches anyone.

Yeah, thinko.

-- 
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com 

  reply	other threads:[~2006-07-11 18:44 UTC|newest]

Thread overview: 133+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-07-05  8:49 [patch] uninline init_waitqueue_*() functions Ingo Molnar
2006-07-05  9:31 ` Andrew Morton
2006-07-05  9:32   ` Ingo Molnar
2006-07-05  9:53     ` Andrew Morton
2006-07-05 10:26       ` Ingo Molnar
2006-07-05 11:30         ` Ingo Molnar
2006-07-05 11:46           ` Ingo Molnar
2006-07-05 17:10             ` Andrew Morton
2006-07-05 19:35               ` Ingo Molnar
2006-07-05 20:18                 ` Andrew Morton
2006-07-05 20:36                   ` Linus Torvalds
2006-07-05 20:47                     ` Ingo Molnar
2006-07-05 21:15                       ` Ingo Molnar
2006-07-05 21:21                       ` Linus Torvalds
2006-07-05 21:45                         ` Ingo Molnar
2006-07-05 21:58                           ` Randy.Dunlap
2006-07-05 22:00                             ` Ingo Molnar
2006-07-05 22:10                               ` Randy.Dunlap
2006-07-05 22:27                                 ` Ingo Molnar
2006-07-05 23:15                               ` Adrian Bunk
2006-07-05 22:09                           ` Linus Torvalds
2006-07-05 22:30                             ` Ingo Molnar
2006-07-05 23:11                             ` Linus Torvalds
2006-07-06  8:16                               ` [patch] spinlocks: remove 'volatile' Ingo Molnar
2006-07-06  8:23                                 ` Ingo Molnar
2006-07-06  9:27                                 ` Heiko Carstens
2006-07-06  9:34                                   ` Arjan van de Ven
2006-07-06 11:59                                 ` linux-os (Dick Johnson)
2006-07-06 12:01                                   ` Arjan van de Ven
2006-07-06 12:29                                     ` linux-os (Dick Johnson)
2006-07-06 12:39                                       ` Arjan van de Ven
2006-07-06 13:39                                         ` J.A. Magallón
2006-07-06 13:43                                           ` Arjan van de Ven
2006-07-06 14:05                                           ` Chase Venters
2006-07-06 14:26                                           ` Andreas Schwab
2006-07-06 16:40                                       ` Nick Piggin
2006-07-06 23:19                                       ` David Schwartz
2006-07-06 18:15                                     ` Mark Lord
2006-07-06 19:15                                       ` Linus Torvalds
2006-07-06 19:33                                         ` Chris Friesen
2006-07-06 19:37                                           ` Mark Lord
2006-07-06 20:28                                             ` Chris Friesen
2006-07-06 20:32                                               ` Linus Torvalds
2006-07-06 19:38                                           ` Arjan van de Ven
2006-07-06 19:41                                           ` Måns Rullgård
2006-07-06 19:42                                           ` Jeff Garzik
2006-07-06 19:58                                           ` Linus Torvalds
2006-07-06 20:27                                             ` Mark Lord
2006-07-06 20:40                                             ` Chris Friesen
2006-07-06 21:00                                               ` Linus Torvalds
2006-07-08  8:40                                         ` Avi Kivity
2006-07-08  8:51                                           ` Arjan van de Ven
2006-07-08  9:20                                             ` Avi Kivity
2006-07-08  9:51                                               ` Arjan van de Ven
2006-07-08 10:18                                                 ` Avi Kivity
2006-07-08 10:28                                                   ` Thomas Gleixner
2006-07-09  4:19                                                   ` Benjamin Herrenschmidt
2006-07-09 12:47                                                     ` Avi Kivity
2006-07-09 19:16                                                       ` David Schwartz
2006-07-09 19:51                                                         ` Theodore Tso
2006-07-09 20:40                                                           ` [OT] 'volatile' in userspace Rutger Nijlunsing
2006-07-10  3:42                                                             ` Theodore Tso
2006-07-10 17:00                                                               ` Joshua Hudson
2006-07-10 17:54                                                                 ` Nick Piggin
2006-07-11  7:48                                                                   ` Jan Engelhardt
2006-07-11 11:53                                                                     ` Nick Piggin [this message]
2006-07-11 19:09                                                                       ` Björn Steinbrink
2006-07-11 20:55                                                                       ` Jeff Dike
2006-07-10 18:54                                                                 ` Jeff Dike
2006-07-10 20:09                                                                   ` Philippe Troin
2006-07-10 20:52                                                                     ` Jeff Dike
2006-07-06 16:07                                   ` [patch] spinlocks: remove 'volatile' Linus Torvalds
2006-07-06 16:13                                     ` Linus Torvalds
2006-07-06 17:04                                       ` Jeff Garzik
2006-07-06 17:52                                       ` linux-os (Dick Johnson)
2006-07-06 18:00                                         ` Linus Torvalds
2006-07-06 21:02                                           ` J.A. Magallón
2006-07-06 21:12                                             ` Linus Torvalds
2006-07-06 18:10                                         ` Michael Buesch
2006-07-06 18:16                                         ` Chase Venters
2006-07-07 18:16                                         ` Krzysztof Halasa
2006-07-07 19:51                                           ` linux-os (Dick Johnson)
2006-07-07 20:25                                             ` Linus Torvalds
2006-07-07 21:22                                               ` linux-os (Dick Johnson)
2006-07-07 21:48                                                 ` Chase Venters
2006-07-08 10:00                                                   ` Krzysztof Halasa
2006-07-08 13:41                                                     ` Chase Venters
2006-07-08 20:09                                                       ` Krzysztof Halasa
2006-07-08 20:40                                                         ` Chase Venters
2006-07-08 20:47                                                           ` Chase Venters
2006-07-09 10:57                                                           ` Krzysztof Halasa
2006-07-07 21:59                                                 ` Linus Torvalds
2006-07-07 22:06                                                   ` Linus Torvalds
2006-07-08 20:49                                                   ` Pavel Machek
2006-07-08 21:43                                                     ` Linus Torvalds
2006-07-07 22:05                                                 ` J.A. Magallón
2006-07-07 22:22                                                   ` Chase Venters
2006-07-07 22:37                                                     ` J.A. Magallón
2006-07-08  9:33                                                       ` David Schwartz
2006-07-07 22:49                                                     ` J.A. Magallón
2006-07-07 22:59                                                       ` Vadim Lobanov
2006-07-07 23:18                                                       ` Chase Venters
2006-07-07 23:36                                                   ` Davide Libenzi
2006-07-07 22:09                                                 ` Ingo Molnar
2006-07-08  7:36                                                   ` Ingo Molnar
2006-07-07 20:39                                             ` Krzysztof Halasa
2006-07-07 23:06                                             ` Björn Steinbrink
2006-07-08  8:36                                             ` Avi Kivity
2006-07-06 19:32                                       ` Jan Engelhardt
2006-07-06 20:26                                         ` Jeremy Fitzhardinge
2006-07-06 20:55                                           ` Jan Engelhardt
2006-07-06 21:07                                             ` Linus Torvalds
2006-07-06 19:56                                 ` Linus Torvalds
2006-07-06 20:34                                   ` Linus Torvalds
2006-07-08 22:50                                     ` Ralf Baechle
2006-07-09  3:09                                       ` Linus Torvalds
2006-07-09  3:07                                     ` Keith Owens
2006-07-09  3:29                                       ` Linus Torvalds
2006-07-09  3:43                                         ` Keith Owens
2006-07-09  3:58                                       ` Linus Torvalds
2006-07-09  6:13                                         ` David Miller
2006-07-09 14:28                                         ` Roman Zippel
2006-07-09 15:27                                           ` Linus Torvalds
2006-07-06  8:18                               ` [patch] lockdep: clean up completion initializer in smpboot.c Ingo Molnar
2006-07-06  8:23                               ` [patch] uninline init_waitqueue_*() functions Ingo Molnar
2006-07-06  9:02                                 ` Andrew Morton
2006-07-06  9:12                                   ` [patch] uninline init_waitqueue_head() Ingo Molnar
2006-07-05 20:45                   ` [patch] uninline init_waitqueue_*() functions Ingo Molnar
2006-07-05 10:37     ` Christoph Hellwig
2006-07-05 10:44       ` Andrew Morton
2006-07-05 10:46         ` Andrew Morton
2006-07-05 10:47         ` Ingo Molnar
2006-07-05  9:54 ` [patch] uninline init_waitqueue_*() functions, fix Ingo Molnar

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=44B39151.10600@yahoo.com.au \
    --to=nickpiggin@yahoo.com.au \
    --cc=jengelh@linux01.gwdg.de \
    --cc=joshudson@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.