Re: [Sqlrelay-discussion] Forked listener removes unix socket file (patch available)

[Renat S. <sr...@st...>]

Hello David,

I've made patches for rudiments and sqlrelay to handle signals by flag. 
Please check it and tell what your thoughts are.

11.11.2011 09:50, David Muse пишет:
> I applied the fix and it's in CVS now.
>
> You're right about signal handlers setting flags and the main app
> testing for them and calling the shutdown code itself.  That would
> definitely eliminate race conditions, like a signal being received
> before isforkedlistener is set but then the shutdown code testing
> isforkedlistener.
>
> I have wondered about how to deal with problems like that before.  I
> can't believe the flag solution never occurred to me.  It seems so
> obvious now.  Feel free to work on that :)
>
> Dave
>
> On 11/11/2011 12:09 AM, Renat Sabitov wrote:
>> Yes, it might be a better solution.
>>
>> Yet, calling destructors and manipulating semaphores and shared memory
>> in signal handler is not recommended at all. The best way to handle a
>> signal is to fire some flag in the handler and then check it in the main
>> program flow.
>>
>> 11.11.2011 02:39, David Muse пишет:
>>> Ahhh, I see the problem...
>>>
>>> I think a cleaner solution might be to remove the setting of pidfile to
>>> NULL after the fork() and just wrap the removal of the pid and unixport
>>> files with an "if (!isforkedchild) {" in the destructor.  Then the
>>> semset, idmemory and cmdl objects would still be freed.
>>>
>>> What do you think?
>>>
>>> Dave
>
>
>
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Renat Sabitov   e-mail: sr...@st...
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