just-in-time debugging?

[Tony Hoyle <tmh@nothing-on.tv>]

Is there a way (kernel or userspace... doesn't matter) that gdb/ddd
could be invoked when a program is about
to dump core, or perhaps on a certain signal (that the app could deliver
to itself when required).  The latter case
is what I need right now, as I have to debug an app that breaks
seemingly randomly & I need to halt when
certain assertions fail.  Core dumps aren't much use as you can't resume
them, otherwise I'd just force a segfault
or something.

I had a look at the do_coredump stuff and it looks like it could be
altered to call gdb in the same way that
modprobe gets called by kmod... however I don't sufficiently know the
code to work out whether it'd work properly
or not.  

A patch to glibc would perhaps be better, but I know that code even
less!

Something like responding to SIGTRAP would probably be ideal.

Tony

-- 

"Two weeks before due date, the programmers work 22 hour days cobbling an
 application from... (apparently) one programmer bashing his face into the
 keyboard." -- Dilbert

tmh@magenta-netlogic.com                http://www.nothing-on.tv