Re: [RFA] Checkpoint: wait the defunct process when delete it

[Michael Snyder <msnyder@vmware.com>]

Follow-up to my last reply...


Hui Zhu wrote:
> Hi,
> 
> I found that when we delete the checkpoint process, it keep defunct.
> This is because the parent process is still running and didn't wait
> it.
> So I add a wait_ptid function after ptrace kill.
> 
> Please help me review it.
> 
> Thanks,
> Hui
> 
> 2010-05-09  Hui Zhu  <teawater@gmail.com>
> 
> 	* linux-fork.c (wait_ptid): New function.
> 	(delete_checkpoint_command): Call wait_ptid.
> 
> 
> ---
>  linux-fork.c |   32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> --- a/linux-fork.c
> +++ b/linux-fork.c
> @@ -410,6 +410,35 @@ linux_fork_detach (char *args, int from_
>      delete_fork (inferior_ptid);
>  }
> 
> +static int
> +wait_ptid (ptid_t ptid)
> +{
> +  struct objfile *waitpid_objf;
> +  struct value *waitpid_fn = NULL;
> +  struct value *argv[4];
> +  struct gdbarch *gdbarch = get_current_arch ();
> +
> +  /* Get the waitpid_fn.  */
> +  if (lookup_minimal_symbol ("waitpid", NULL, NULL) != NULL)
> +    waitpid_fn = find_function_in_inferior ("waitpid", &waitpid_objf);
> +  if (!waitpid_fn)
> +    if (lookup_minimal_symbol ("_waitpid", NULL, NULL) != NULL)
> +      waitpid_fn = find_function_in_inferior ("waitpid", &waitpid_objf);
> +  if (!waitpid_fn)
> +    return -1;
> +
> +  /* Get the argv.  */
> +  argv[0] = value_from_longest (builtin_type (gdbarch)->builtin_int,
> PIDGET (ptid));
> +  argv[1] = value_from_longest (builtin_type (gdbarch)->builtin_int, 0);
> +  argv[2] = value_from_longest (builtin_type (gdbarch)->builtin_int, 0);
> +  argv[3] = 0;

      old_cleanup = save_inferior_ptid ();
      inferior_ptid = fd->parent_ptid;

Something like this?  Then the original inferior_ptid will be
restored when you do

> +  if (call_function_by_hand (waitpid_fn, 3, argv) == 0)
> +    return -1;

      do_cleanups();

> +  return 0;
> +}
> +
>  /* Fork list <-> user interface.  */
> 
>  static void
> @@ -431,6 +460,9 @@ Please switch to another checkpoint befo
>    if (ptrace (PTRACE_KILL, PIDGET (ptid), 0, 0))
>      error (_("Unable to kill pid %s"), target_pid_to_str (ptid));
> 
> +  if (wait_ptid (ptid))
> +    error (_("Unable to wait pid %s"), target_pid_to_str (ptid));
> +
>    if (from_tty)
>      printf_filtered (_("Killed %s\n"), target_pid_to_str (ptid));