how to get traceback from segfault signal handler?

[Pete Shinners]

i'd really-really like to get the python traceback from inside my own 
installed signal handler. i have a semi-big set of c extension modules, 
and it's sadly not too shocking for things to crash. (nothing of 
python's fault, for sure). but it would really aid everyone involved if 
a stacktrace could be printed, similar to a normal exception.

the main problem it seems to come down to, i can't get ahold of the 
interpreter lock, because the thread execution is stopped. something 
like "PyThreadState_Get_VoidWarranty()" would really help me out?