Re: RFA[threads]: Fork event updates, part the thirteenth

[Michael Snyder <msnyder@redhat.com>]

Daniel Jacobowitz wrote:
> 
> Now is where it starts to get interesting.  Michael, I mentioned this patch
> to you at lunch last week.  If you take a short-lived program, run it, and
> detach it, and run it again, you'll see the exit of the _previous_ copy.
> Then GDB gets hopelessly confused.  I have a testcase for this which I'll
> post in a moment.
> 
> The reason it's included here is that that's essentially what happens if you
> are using "set follow-fork-mode child".  We detach from the parent, which
> exits, confusing GDB.
> 
> Is this OK?

Hi Dan, 

Please excuse the delay.  This seems OK.  In child_wait, 
would it be possible to add a check to see if the exiting
process is in our lwp list?

Michael

> 
> --
> Daniel Jacobowitz
> MontaVista Software                         Debian GNU/Linux Developer
> 
> 2002-12-15  Daniel Jacobowitz  <drow@mvista.com>
> 
>         * lin-lwp.c (child_wait): Ignore exit statuses for processes other
>         than inferior_ptid.
>         (lin_lwp_wait): Ignore exit statuses for unknown LWPs.
> 
> Index: lin-lwp.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/lin-lwp.c,v
> retrieving revision 1.39
> diff -u -p -r1.39 lin-lwp.c
> --- lin-lwp.c   9 Dec 2002 18:41:42 -0000       1.39
> +++ lin-lwp.c   15 Dec 2002 21:16:34 -0000
> @@ -964,6 +964,14 @@ child_wait (ptid_t ptid, struct target_w
>         pid = waitpid (GET_PID (ptid), &status, __WCLONE);
>        save_errno = errno;
> 
> +      /* Make sure we don't report an event for the exit of the
> +        original program, if we've detached from it.  */
> +      if (pid != -1 && ! WIFSTOPPED (status) && pid != GET_PID (inferior_ptid))
> +       {
> +         pid = -1;
> +         save_errno = EINTR;
> +       }
> +
>        clear_sigio_trap ();
>        clear_sigint_trap ();
>      }
> @@ -1091,6 +1099,17 @@ lin_lwp_wait (ptid_t ptid, struct target
>           gdb_assert (pid == -1 || lwpid == pid);
> 
>           lp = find_lwp_pid (pid_to_ptid (lwpid));
> +
> +         /* Make sure we don't report an event for the exit of an LWP not in
> +            our list, i.e.  not part of the current process.  This can happen
> +            if we detach from a program we original forked and then it
> +            exits.  */
> +         if (! WIFSTOPPED (status) && ! lp)
> +           {
> +             status = 0;
> +             continue;
> +           }
> +
>           if (! lp)
>             {
>               lp = add_lwp (BUILD_LWP (lwpid, GET_PID (inferior_ptid)));