From: Neil Horman <nhorman@redhat.com>
To: hzhong@cisco.com
Cc: "'Andries Brouwer'" <aebr@win.tue.nl>,
"'Joris van Rantwijk'" <joris@eljakim.nl>,
"'Alan Cox'" <alan@lxorguk.ukuu.org.uk>,
"'Linux Kernel Mailing List'" <linux-kernel@vger.kernel.org>
Subject: Re: UDP recvmsg blocks after select(), 2.6 bug?
Date: Wed, 06 Oct 2004 16:41:54 -0400 [thread overview]
Message-ID: <41645892.9060105@redhat.com> (raw)
In-Reply-To: <003301c4abdc$c043f350$b83147ab@amer.cisco.com>
Hua Zhong wrote:
>>It may need fixing in the sense that it must point out that
>>the Linux kernel
>>might not conform to POSIX in its handling of select on sockets.
>
>
> Agreed.
>
>
>>We now not only have "man 2 select", but also "man 3p select".
>>This is the POSIX text:
>>
>> A descriptor shall be considered ready for reading when a
>> call to an input function with O_NONBLOCK clear would not
>> block, whether or not the function would transfer data
>> successfully. (The function might return data, an end-of-
>> file indication, or an error other than one indicating
>> that it is blocked, and in each of these cases the
>> descriptor shall be considered ready for reading.)
>>
>>As far as I can interpret these sentences, Linux does not conform.
>
Again, shouldn't this just mean that recvfrom should not be called
without the MSG_ERRQUEUE flag set? From the above description, I read
that select returning with an indication that a descriptor is ready for
reading could mean that it has an error message queued to it, rather
than in-band data. If you then call recvfrom/recv/recvmsg without
indicating that you want to receive the error indications as well, then
isn't that just another example of improper coding, since recvfrom would
have returned immeidately, as select indicated, had the appropriate read
flags been set?
Neil
>
> How hard is it to treat the next read to the fd as NON_BLOCKING, even if
> it's not set?
>
>
>>Andries
>
>
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--
/***************************************************
*Neil Horman
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*Red Hat, Inc.
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next prev parent reply other threads:[~2004-10-06 21:20 UTC|newest]
Thread overview: 191+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-06 14:52 UDP recvmsg blocks after select(), 2.6 bug? Joris van Rantwijk
2004-10-06 15:01 ` David S. Miller
2004-10-06 15:13 ` Chris Friesen
2004-10-06 15:15 ` Richard B. Johnson
2004-10-06 15:21 ` David S. Miller
2004-10-06 15:29 ` Richard B. Johnson
2004-10-06 15:42 ` David S. Miller
2004-10-06 15:57 ` Chris Friesen
2004-10-06 15:44 ` Lars Marowsky-Bree
2004-10-07 1:16 ` Paul Jakma
2004-10-07 7:10 ` Chris Friesen
2004-10-07 11:53 ` Paul Jakma
2004-10-07 13:32 ` Martijn Sipkema
2004-10-07 12:53 ` Paul Jakma
2004-10-07 13:12 ` Richard B. Johnson
2004-10-07 14:07 ` Martijn Sipkema
2004-10-07 13:19 ` Paul Jakma
2004-10-07 13:36 ` Paul Jakma
2004-10-07 15:01 ` Jean-Sebastien Trottier
2004-10-07 16:20 ` Chris Friesen
2004-10-07 18:20 ` Hua Zhong
2004-10-07 18:33 ` Chris Friesen
2004-10-07 22:41 ` Martijn Sipkema
2004-10-07 21:49 ` Chris Friesen
2004-10-07 22:00 ` David S. Miller
2004-10-07 22:24 ` Chris Friesen
2004-10-07 22:26 ` David S. Miller
2004-10-07 22:39 ` Chris Friesen
2004-10-07 22:42 ` David S. Miller
2004-10-07 23:27 ` Chris Friesen
2004-10-08 0:04 ` Ben Greear
2004-10-08 2:51 ` Mark Mielke
2004-10-08 3:39 ` David S. Miller
2004-10-08 3:48 ` Mark Mielke
2004-10-08 3:59 ` David S. Miller
2004-10-07 23:19 ` Martijn Sipkema
2004-10-07 22:24 ` David S. Miller
2004-10-07 22:33 ` Alan Curry
2004-10-07 22:42 ` Mark Mielke
2004-10-07 22:47 ` David S. Miller
2004-10-07 23:00 ` Mark Mielke
2004-10-07 23:07 ` David S. Miller
2004-10-08 6:10 ` Theodore Ts'o
2004-10-08 15:20 ` Mark Mielke
2004-10-08 0:37 ` Lee Revell
2004-10-07 22:46 ` Hua Zhong
2004-10-07 22:48 ` David S. Miller
2004-10-07 23:17 ` Martijn Sipkema
2004-10-07 13:45 ` Alan Cox
2004-10-07 16:32 ` Martijn Sipkema
2004-10-07 14:50 ` Alan Cox
2004-10-07 21:58 ` mmap specification - was: ... select specification Andries Brouwer
2004-10-07 22:17 ` Chris Wedgwood
2004-10-07 22:34 ` Andries Brouwer
2004-10-07 22:32 ` Kyle Moffett
2004-10-07 22:46 ` Andries Brouwer
2004-10-07 23:30 ` Kyle Moffett
2004-10-08 9:19 ` Andries Brouwer
2004-10-09 21:10 ` Martijn Sipkema
2004-10-07 13:48 ` UDP recvmsg blocks after select(), 2.6 bug? Alan Cox
2004-10-07 14:57 ` Richard B. Johnson
2004-10-07 15:18 ` Adam Heath
2004-10-07 16:39 ` Martijn Sipkema
2004-10-07 16:09 ` Mark Mielke
2004-10-07 17:18 ` Chris Friesen
2004-10-06 15:31 ` Chris Friesen
2004-10-06 15:41 ` David S. Miller
2004-10-06 16:07 ` Richard B. Johnson
2004-10-06 16:57 ` Neil Horman
2004-10-06 15:59 ` Paul Jackson
2004-10-06 16:35 ` Martijn Sipkema
2004-10-06 15:30 ` Chris Friesen
2004-10-06 15:09 ` Richard B. Johnson
2004-10-06 15:18 ` bert hubert
2004-10-06 16:41 ` Alan Cox
2004-10-06 18:04 ` Joris van Rantwijk
2004-10-06 19:30 ` Andries Brouwer
2004-10-06 19:23 ` Alan Cox
2004-10-06 22:08 ` Martijn Sipkema
2004-10-06 20:25 ` Alan Cox
2004-10-06 22:15 ` Andries Brouwer
2004-10-06 22:32 ` David S. Miller
2004-10-06 23:25 ` YOSHIFUJI Hideaki / 吉藤英明
2004-10-06 23:11 ` Willy Tarreau
2004-10-06 19:43 ` Hua Zhong
2004-10-06 19:54 ` Chris Friesen
2004-10-06 19:59 ` Hua Zhong
2004-10-06 20:10 ` Chris Friesen
2004-10-06 21:45 ` Martijn Sipkema
2004-10-06 23:35 ` David S. Miller
2004-10-06 20:06 ` David S. Miller
2004-10-06 20:18 ` Chris Friesen
2004-10-06 20:26 ` Hua Zhong
2004-10-06 20:38 ` Andries Brouwer
2004-10-06 20:58 ` Joris van Rantwijk
2004-10-06 22:29 ` David S. Miller
2004-10-07 16:08 ` Adrian Phillips
2004-10-06 20:06 ` Olivier Galibert
2004-10-06 23:35 ` David S. Miller
2004-10-07 0:19 ` Olivier Galibert
2004-10-07 0:29 ` David S. Miller
2004-10-07 10:56 ` Martijn Sipkema
2004-10-08 6:41 ` Willy Tarreau
2004-10-08 15:27 ` Mark Mielke
2004-10-15 22:42 ` Robert White
2004-10-15 23:33 ` David Schwartz
2004-10-16 0:59 ` Chris Friesen
2004-10-16 2:35 ` Mark Mielke
2004-10-16 4:23 ` David Schwartz
2004-10-16 4:35 ` Mark Mielke
2004-10-16 4:58 ` David Schwartz
2004-10-16 6:25 ` Mark Mielke
2004-10-16 21:44 ` Roland Kuhn
2004-10-17 0:06 ` Mark Mielke
2004-10-17 0:30 ` David Schwartz
2004-10-17 14:47 ` Mark Mielke
2004-10-17 0:28 ` David Schwartz
2004-10-17 13:35 ` Lars Marowsky-Bree
2004-10-17 14:17 ` Buddy Lucas
2004-10-17 15:05 ` Mark Mielke
2004-10-17 15:40 ` Buddy Lucas
2004-10-17 16:13 ` Lee Revell
2004-10-17 17:35 ` Jesper Juhl
2004-10-17 18:04 ` Buddy Lucas
2004-10-17 18:06 ` Lars Marowsky-Bree
2004-10-17 18:21 ` Buddy Lucas
2004-10-17 20:04 ` Martijn Sipkema
2004-10-17 20:08 ` Lars Marowsky-Bree
2004-10-17 17:35 ` Martijn Sipkema
2004-10-17 17:33 ` Buddy Lucas
2004-10-17 19:58 ` Martijn Sipkema
2004-10-17 19:33 ` Buddy Lucas
2004-10-17 20:11 ` Lars Marowsky-Bree
2004-10-17 20:25 ` Buddy Lucas
2004-10-17 20:42 ` Martijn Sipkema
2004-10-17 20:02 ` Buddy Lucas
2004-10-17 18:53 ` David Schwartz
2004-10-17 19:26 ` Hua Zhong
2004-10-17 20:32 ` Martijn Sipkema
2004-10-17 19:21 ` Hua Zhong
2004-10-17 17:22 ` Lars Marowsky-Bree
2004-10-17 17:54 ` Buddy Lucas
2004-10-17 18:05 ` Lars Marowsky-Bree
2004-10-17 18:06 ` Mark Mielke
2004-10-20 21:31 ` H. Peter Anvin
2004-10-20 21:58 ` Chris Friesen
2004-10-20 22:00 ` H. Peter Anvin
2004-10-20 22:12 ` Chris Friesen
2004-10-20 23:16 ` David Schwartz
2004-10-21 1:03 ` Chris Friesen
2004-10-21 1:38 ` David Schwartz
2004-10-21 3:01 ` Michael Clark
2004-10-21 3:52 ` Michael Clark
2004-10-21 4:10 ` H. Peter Anvin
2004-10-21 5:06 ` Chris Friesen
2004-10-21 5:11 ` H. Peter Anvin
2004-10-21 5:50 ` Chris Friesen
2004-10-21 5:58 ` H. Peter Anvin
2004-10-21 15:18 ` Chris Friesen
2004-10-21 6:14 ` Michael Clark
2004-10-17 14:52 ` Mark Mielke
2004-10-16 18:25 ` Andries Brouwer
2004-10-17 0:28 ` David Schwartz
2004-10-17 12:22 ` Andries Brouwer
2004-10-16 10:24 ` Willy Tarreau
2004-10-16 13:21 ` Mark Mielke
2004-10-18 22:25 ` Robert White
2004-10-06 20:41 ` Neil Horman [this message]
2004-10-06 22:27 ` Chris Friesen
2004-10-06 23:32 ` Neil Horman
2004-10-06 23:36 ` David S. Miller
2004-10-07 19:31 ` David Schwartz
2004-10-07 22:36 ` Martijn Sipkema
2004-10-08 0:19 ` David Schwartz
2004-10-09 19:21 ` Martijn Sipkema
2004-10-09 18:28 ` David Schwartz
2004-10-09 18:49 ` Mark Mielke
2004-10-09 21:00 ` Martijn Sipkema
2004-10-09 22:59 ` Mark Mielke
-- strict thread matches above, loose matches on Subject: below --
2004-10-06 15:30 Dan Kegel
2004-10-07 4:50 Dan Kegel
2004-10-07 8:04 ` bert hubert
2004-10-07 8:28 ` Adam Heath
2004-10-07 10:38 ` Martijn Sipkema
2004-10-07 10:07 ` Adam Heath
2004-10-07 11:29 ` Martijn Sipkema
2004-10-07 18:16 linux
2004-10-09 12:07 ` Colin Phipps
[not found] <fa.haprsoi.8k8kbk@ifi.uio.no>
[not found] ` <fa.isqjio8.ok2coo@ifi.uio.no>
2004-10-09 13:24 ` Bodo Eggert
2004-10-19 1:21 John Pearson
2004-10-19 13:50 ` Colin Phipps
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