You can set a signal handler in C (via Inline) and maybe get more information on what is triggering the signal if you use sigaction's SA_SIGINFO flag and examine the siginfo_t that's passed to the signal handler. See http://www.opengroup.org/onlinepubs/000095399/basedefs/signal.h.html (free registration required) for details.

(Beginning with perl5.8.9, you'll be able to do this in pure perl with POSIX::SigAction.)