Re: [Qemu-devel] [RFC] Continuous work on sandboxing

[Eduardo Otubo <otubo@linux.vnet.ibm.com>]

On 04/26/2013 07:17 PM, Paolo Bonzini wrote:
> Il 26/04/2013 23:07, Paul Moore ha scritto:
>>>> 3. Debugging and/or learning mode - third party libraries still have the
>>>> problem of interfering in the Qemu's signal mask. According to some
>>>> previous discussions, perhaps patch all external libraries that mass up
>>>> with this mask (spice, for example) is a way to solve it. But not sure
>>>> if it worth the time spent. Would like to hear you guys.
>> I think patching all the libraries is a losing battle, I think we need to
>> pursue alternate debugging techniques.
>
> It is really only about patching libraries that create threads _and_
> block all signals in the newly-created thread (to not interfere with the
> program's own handling of the signals).  In this case, the per-thread
> signals (SIGFPE/SIGSEGV/SIGBUS/SIGSYS/SIGILL) should be left unblocked,
> but SIGSYS is often forgotten.

But otherwise you have a fast way to test third party linked libraries, 
I would have to test it each one manually. How many libraries are linked 
to Qemu today?

>
> I don't think there are many libraries like this, but fixing SPICE at
> least should definitely be welcome.
>
> In fact QEMU's own util/qemu-thread-posix.c does not unblock those
> signals.  Eduardo, can you submit a patch for that?

I sure can.
-- 
Eduardo Otubo
IBM Linux Technology Center