[jira] [Commented] (THRIFT-3848) As an implementer of a perl socket server, I do not want to have to remember to ignore SIGCHLD for it to work properly

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/THRIFT-3848?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15367792#comment-15367792 ] 

ASF GitHub Bot commented on THRIFT-3848:
----------------------------------------

GitHub user jeking3 opened a pull request:

    https://github.com/apache/thrift/pull/1040

    THRIFT-3848: Perl ForkingServer must ignore SIGCHLD to avoid infinite loop

    

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/jeking3/thrift defect/THRIFT-3848

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/thrift/pull/1040.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #1040
    
----
commit 1bc6497f502d45e3483c851f95fd6feff2cbf9a2
Author: Jim King <ji...@simplivity.com>
Date:   2016-07-07T01:50:23Z

    THRIFT-3848: Perl ForkingServer must ignore SIGCHLD to avoid infinite loop

----


> As an implementer of a perl socket server, I do not want to have to remember to ignore SIGCHLD for it to work properly
> ----------------------------------------------------------------------------------------------------------------------
>
>                 Key: THRIFT-3848
>                 URL: https://issues.apache.org/jira/browse/THRIFT-3848
>             Project: Thrift
>          Issue Type: Bug
>          Components: Perl - Library
>    Affects Versions: 0.8, 0.9, 0.9.1, 0.9.2, 0.9.3
>         Environment: Ubuntu 14.04, perl forking server, C++ client
>            Reporter: James E. King, III
>            Assignee: James E. King, III
>
> In a project I work on, we use a perl thrift server as a mock to simulate something in production.  A C++ client connects, makes a call, and disconnects.  The perl server is a forking server.
> I found that if I do not explicity ignore SIGCHLD, I can accept one connection and process it, but when it disconnects, the subsequent accept call is interrupted by a SIGCHLD and results in a useless handle that can_read says cannot be read.  This puts Server.pm into an infinite accept/read/fail loop.
> Question to those in the know... should perl's ForkingServer serve() implementation explicitly set SIGCHLD to IGNORE to avoid this situation?  If we do not, folks trying to use it might be as confounded as I was as to why this is happening.  If we do, it might change the behavior of programs using the perl forking server.
> My inclination is to document this behavior, that perl's ForkingServer will set SIGCHLD to IGNORE for proper operation.
> Tagging [~djnym], [~jensg], [~nsuke] for comment.  I've observed this behavior as far back as thrift-0.8.0.



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