Forgot to cc: this to utrace-devel... Srikar Dronamraju wrote: > Hi Chris, > > I was going through froggy code and had couple of comments > > In the Froggy interface code i.e froggy/froggy/froggy.c > reap_listener() under "case RESP_EXIT" code, we seem to be printing > orig_code twice. I guess the second one should be code. > i.e > fprintf (stdout, "[%4ld] exited, orig code %ld, code %ld\n", > resp.resp_exit.pid, > resp.resp_exit.orig_code, > - resp.resp_exit.orig_code); > + resp.resp_exit.code); > break; >
The printf()s in froggy.c:resp_listener() are all temporary diagnostics
and will ultimately be removed. I don't know which version of froggy
you have, but if you'll look at the latest under the RESP_SYSCALL_ENTRY
case you'll see:
if (froggy->syscall_fcn)
(*froggy->syscall_fcn)(resp.resp_syscall.nr,
(pid_t)resp.resp_syscall.pid,
®s);
which invokes a registered callback to the client. Take a look at
demos/stracef/stracef.c, which includes a line
froggy_set_syscall_handler (froggy, syscall_fcn);
that sets the callback used above to
static void
syscall_fcn (long nr, pid_t pid, struct pt_regs * regs)
{
char * sc = syscalls_index[nr]->key;
fprintf (stdout, "[%5d] syscall %4d (%s)\n",
(int)pid, nr, sc);
}
Since thats in the client code, it can do anything you want it to do.
> case RESP_SYSCALL_ENTRY:
>
>
> In froogy/module/control.c
> do_process_attach_task() and do_process_attach share lot of code and we
> could probably use common function for the shared code.
>
do_process_attach_task() has been removed. Originally, I had it set up
such that client-thread report_clone wasa used to automatically attach
child processes that were ultimately to be execve()ed as code to be
debugged, but I've replaced that with something more explicitly like
ptrace(PTRACE_TRACEME,...) and the older code has been #ifdef-ed out.
(I'll remove it entirely when I'm sure I don't need it anymore...)
> Similarly do_shutdown() shares code with do_process_detach and we could
> probably make do_shutdown() call do_process_detach.
>
It sounds like you don't have the latest snapshot--I did a /lot/ of
cleanup in the shutdown/detach code last week and they
> Do we plan to use report_jctl in the near future. utrace_ops has
> report_jctl set to NULL however we have defined report_jctl() function
> which never gets used. Similarly for unsafe_exec and tracer_task.
>
> Can you explain why you would want to attach with
> UTRACE_ATTACH_EXCLUSIVE always? So even if I want to trace the same
> program twice from froggy then I shouldn't be able to do it?
>
>
> --
> Thanks and Regards
> Srikar
>
--
Chris Moller
I know that you believe you understand what you think I said, but
I'm not sure you realize that what you heard is not what I meant.
-- Robert McCloskey
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