Stack smashing while using a lot of connections

[Anton Kortunov]

libfcgi uses select syscall, when some applications tryes to use more than 1024 connections from web-server it crashes. There is a solutions for this problem: use poll in os_unix.c instead of select. Patch with this change is attached to this bug. This patch was written in Yandex and successfully used for a several months.

LIBFCGI_OS_CLOSE_POLL_TIMEOUT and LIBFCGI_IS_AF_UNIX_KEEPER_POLL_TIMEOUT environment variables are added to control poll timeouts in Os_Close and is_af_unix_keeper functions accordingly.

$ lsb_release -rd
Description: Ubuntu 10.04.2 LTS
Release: 10.04

Package libfcgi0ldbl 2.4.0-7.1ubuntu1

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "poll.patch" of this bug report has been identified as being a patch. The ubuntu-reviewers team has been subscribed to the bug report so that they can review the patch. In the event that this is in fact not a patch you can resolve this situation by removing the tag 'patch' from the bug report and editing the attachment so that it is not flagged as a patch. Additionally, if you are member of the ubuntu-reviewers team please also unsubscribe the team from this bug report.

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[Launchpad Janitor (janitor)]

This bug was fixed in the package libfcgi - 2.4.0-8.1ubuntu1

---------------
libfcgi (2.4.0-8.1ubuntu1) quantal; urgency=low

  * Applying patch to use poll instead of select which helps handle
    more than 1024 connections. (LP: #933417). Thanks Anton Kortunov!
 -- Clint Byrum <email address hidden> Sat, 14 Jul 2012 08:20:42 -0700

[Clint Byrum (clint-fewbar)]

Hi Anton. Thanks for the patch. Its simple enough and has a large enough benefit that I've gone ahead and applied it in Ubuntu. I have tried as hard as I can to submit this to the fastcgi-developers mailing list but they seem to have been having problems since May of 2011 so I don't know if it will reach any of them.

[Aarti Dongargaonkar (adongarg)]

I see that the patch has the fix to use poll instead of select in the 2 functions - OS_Close and is_af_unix_keeper. But I see that select is used in one more place in OS_DoIo in os_unix.c. Any reason why this select is not changed to poll? Is there a patch available to fix this? Thanks.