Re: [Log4cplus-devel] Socket close hangs

[palladin <p-a...@ya...>]

On 09/19/2013 01:15 AM, Václav Zeman wrote:
> On 09/18/2013 09:51 AM, palladin wrote:
>> Dear log4cplus devels,
>> log4cplus 1.1.1-RC4
>> <https://sourceforge.net/projects/log4cplus/files/log4cplus-stable/1.1.1/>
>> Linux version 2.6.32-279.22.1.37.0.el6.x86_64 (abuild@noriko) (gcc
>> version 4.4.6 20120305 (Red Hat 4.4.6-4) (GCC) )
>>
>> My application has hung after it have used log4cplus::helpers::Socket
>> from  log4cplus::helpers::ServerSocket::accept,e.g.
>> log4cplus::helpers::Socket clientSocket = mServerSocket.accept();
>> clientSocket was put into log4cplus::thread::AbstractThread worker.
>> Client socket was used in AbstractThread like Socket::read - this is
>> blocking call and the root of issue.
>>
>> Then my application worked for some time  and at the end I did
>> clientSocket.close() from main thread.
>> Due to the fact that log4cplus::helpers::Socket::read is blocking call -
>> my application has hung on AbstractThread::join call.
>>
>> I would like to suggest a fiew fixes to this issue:
>> 1) add non-blocking stuff to log4cplus::helpers::Socket - select or poll.
>> 2) add to log4cplus::helpers::Socket interface system call shutdown( man
>> 2 shutdown ).
> Closing a socket from one thread when the socket is blocked on any
> operation in another thread is AFAIK very unportable.
>
> This could be solved in a way similar to how I have done
> ServerSocket::accept(), which is indeed using poll() to wait for either
> an incoming connection or some data arriving to a special interrupt pipe.
>
> Also, these helpers are there to help log4cplus. They are not there to
> be used as public networking framework/API, so fixing this has a low
> priority for me right now. OTOH, I am open to accepting reasonable patches.
>
>
>
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Dear Václav,
I prefer your solution in ServerSocket interruption. So could you please 
take a look on provided patch?

Sincerely ,
Taras