Re: GDB Python API: stop/continue after breakpoint

Kevin Pouget
2011-03-21T14:20:00Z

cool, that's working perfectly now !

just one thing:

> <python breakpoint outputs>
>
> [Switching to Thread 0x7ffff7de1700 (LWP 2417)]
>
> Breakpoint -9, rdb_notify_event () at replay_db.c:11
> 11 void rdb_notify_event() {}

is there any way / woudn't it be nice to have the ability to disable
the breakpoint hit outputs? at least for the 'internal' breakpoints,
which shouldn't be visible to the user ?

Thanks,

Kevin

On Fri, Mar 11, 2011 at 11:25 AM, Phil Muldoon <pmuldoon@redhat.com> wrote:
>
> Kevin Pouget <kevin.pouget@gmail.com> writes:
>
> > Hello,
> >
> > I've tried the GDB python interface today, which seems quite
> > efficient, but there is one important thing I couldn't figure out by
> > myself:
> >
> > how to restart GDB when a[n internal] breakpoint is hit ?
> > from the testsuite I've got this code:
>
>
> You almost can. One part is pending:
>
> http://sourceware.org/ml/gdb-patches/2011-03/msg00656.html
>
> The implementation of the "stop" API.  The idea behind this is that if a
> breakpoint is hit, that is tracked from Python and has an implemented
> stop method, that method would be called.  You can do what you like in
> that method.  If you want the inferior process to continue, return True
> otherwise return False (and print out/do whatever else you need to do in
> Python).
>
> Because internal breakpoints are not tracked by default in the Python
> Breakpoint API, you would have to create your breakpoint by
> instantiating a gdb.Breakpoint class, and pass the keyword
> internal=True.
>
> So, long story short soon.  OTOH I'm not sure if there is a unhacky way
> of doing it now.  You could use a convenience function, but that patch
> is replacing that hacky way.
>
> Cheers
>
> Phil
> >
> > def breakpoint_stop_handler (event):
> >     if (isinstance (event, gdb.StopEvent)):
> >         print "event type: stop"
> >     if (isinstance (event, gdb.BreakpointEvent)):
> >         print "stop reason: breakpoint"
> >         print "breakpoint number: %s" % (event.breakpoint.number)
> >         if ( event.inferior_thread is not None) :
> >             print "thread num: %s" % (event.inferior_thread.num);
> >         else:
> >             print "all threads stopped"
> >
> > gdb.events.stop.connect (breakpoint_stop_handler)
> >
> >
> > which where I get the notification of the stop, but I'd to be able to
> > tell GDB something like
> >
> > enum bpstat_what_main_action {
> >     /* Remove breakpoints, single step once, then put them back in and
> >        go back to what we were doing.  It's possible that this should
> >        be removed from the main_action and put into a separate field,
> >        to more cleanly handle  BPSTAT_WHAT_CLEAR_LONGJMP_RESUME_SINGLE.  */
> >     BPSTAT_WHAT_SINGLE,
> >     /* Stop silently.  */
> >     BPSTAT_WHAT_STOP_SILENT,
> >
> >     /* Stop and print.  */
> >     BPSTAT_WHAT_STOP_NOISY,
> > ...
> > }
> >
> > to continue silently, stop silently or print the breakpoint hit.
> >
> > is it possible at this stage ?
> >
> > Thanks,
> >
> > Kevin