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https://issues.apache.org/jira/browse/THRIFT-3848?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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James E. King, III updated THRIFT-3848:
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Description:
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.
The serve() method of the ForkingServer needs to explicitly ignore SIGCHLD to
work properly.
I've observed this behavior as far back as thrift-0.8.0 up through 0.9.3.
The workaround is to add the following code before calling serve():
{code}$SIG{CHLD} = 'IGNORE';{code}
was:
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.
> 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. The serve() method of the ForkingServer needs to
> explicitly ignore SIGCHLD to work properly.
> I've observed this behavior as far back as thrift-0.8.0 up through 0.9.3.
> The workaround is to add the following code before calling serve():
> {code}$SIG{CHLD} = 'IGNORE';{code}
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