On 01/04/2015 18:36, Jon TURNEY wrote:
> On 01/04/2015 15:22, Corinna Vinschen wrote:
>> On Apr  1 14:19, Jon TURNEY wrote:
>>> Add ucontext.h header, defining ucontext_t and mcontext_t types.
>>>
>>> Provide sigaction sighandlers with a ucontext_t parameter, containing
>>> stack and
>>> context information.
>>>
>>>     * include/sys/ucontext.h : New header.
>>>     * include/ucontext.h : Ditto.
>>>     * exceptions.cc (call_signal_handler): Provide ucontext_t
>>>     parameter to signal handler function.
>>
>> Patch is ok with a single change:  Please add a "FIXME?" comment to:
>>
>>    else
>>      RtlCaptureContext();
>>
>> On second thought, calling RtlCaptureContext here is probably wrong.
>>
>> What we really need is the context of the thread when calling
>> call_signal_handler I think.
>
> I had the same thought, but this is going to be quite tricky to achieve.

>> It would be better to call RtlCaptureContext
>> before calling call_signal_handler.  But this requires a change in how
>> call_signal_handler is called.
>>
>> We should discuss this at one point, I think.

I noticed that we already prepare a context for continuing after the 
signal for the debugger, so perhaps this is not quite as complex as I 
thought and something like the attached is needed.

It's very hard to reason about if this is doing the right thing when the 
signal is delivered across threads, though.