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Date: Tue, 12 Aug 2008 14:49:41 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] [PATCH] Handle terminating signals.
References: <48A09722.3060106@redhat.com>	<18593.24673.304649.806330@mariner.uk.xensource.com>	<48A1D6A3.4050406@redhat.com>	<20080812.132906.-399282484.imp@bsdimp.com>
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To: qemu-devel@nongnu.org
Cc: Gerd Hoffmann <kraxel@redhat.com>

Gerd Hoffmann wrote:
> M. Warner Losh wrote:
>   
>> In message: <48A1D6A3.4050406@redhat.com>
>>             Gerd Hoffmann <kraxel@redhat.com> writes:
>> : > No, because the program should not attempt to catch SEGV either.
>> : 
>> : Why not?  Can you change your attitude to say "no" without giving
>> : reasons please?
>>
>> The only portable thing one can do when catching SEGV is terminate the
>> program.  Otherwise, when the signal handler returns, SEGV happens
>> again...
>>     
>
> Returning from the signal handler isn't going to work, sure.  The only
> thing I want do is cleaning up before exiting.
>
> Most apps never ever have to care about that.  Sometimes there are good
> reasons to attempt a cleanup even for a SEGV though.  The X-Server for
> example attempts to put the gfx card into a sane state then.
>   

Note my previous suggestion of pipe() + fork() gives you the desired 
cleanup behaviour without having to deal with any of this silliness.  
IMHO, the real problem here is that Xen's domain-0 interface isn't based 
on file descriptors to begin with.  What modern Linux interface that 
requires a clean-up action isn't, afterall?

Regards,

Anthony Liguori

> cheers,
>   Gerd
>
>