Re: Issue with gdbserver --multi / remote-extended on Windows XP

[Pedro Alves <pedro@codesourcery.com>]

Hi,

I don't think anyone responded to this.

On Wednesday 17 September 2008 18:35:15, Dr. Rolf Jansen wrote:
> I experimented a little bit with gdbserver --multi in remote-xtended  
> mode on Windows XP and I had one major problem in debugging a gui  
> application. If I regularly quit the gui app, to which gdbserver is  
> attached, its open windows remain at the screen, and while although  
> inresponsive they are still part of the window hierarchy of Windows.
> 
> 
> Observations:
> - the gui app is terminates itself by calling exit(0).
> - if I quit gdbserver, the open zombie-windows disappear
> - in non-multi/remote-extended-mode gdbserver this problem
>    does not appear, because gdbserver terminates itself
>    together with the application
> 
> 
> I found a solution that works for me, although, there might be better  
> ways.
> 
> At line 1456 of win32-low.c I added:
> 
>        TerminateProcess (current_process_handle,
>                          current_event.u.ExitProcess.dwExitCode);
>        child_continue (DBG_TERMINATE_PROCESS, -1);
> 
> 
> 
> This code is added in event-handler switch() of  
> get_child_debug_event() and the respective case block looks now like:
> 
>      case EXIT_PROCESS_DEBUG_EVENT:
>        OUTMSG2 (("gdbserver: kernel event EXIT_PROCESS_DEBUG_EVENT "
> 		"for pid=%d tid=%x\n",
> 		(unsigned) current_event.dwProcessId,
> 		(unsigned) current_event.dwThreadId));
>        ourstatus->kind = TARGET_WAITKIND_EXITED;
>        ourstatus->value.integer =  
> current_event.u.ExitProcess.dwExitCode;



>        TerminateProcess (current_process_handle,
>                          current_event.u.ExitProcess.dwExitCode);
>        child_continue (DBG_TERMINATE_PROCESS, -1);


Hmm, I haven't tried this, but, are you sure you need to
terminate the process like this?  Wouldn't a
child_continue (DBG_CONTINUE, -1) work here?  It's what
native gdb does (it's in win32_mourn_inferior).
I can't find it now, but I'm almost sure that's documented somewhere
as required for the debugger to do (I scratched my head once at why
was win32_mourn_inferior telling the dead process to continue, and found
that out).  Well, I could be wrong though.


>        CloseHandle (current_process_handle);
>        current_process_handle = NULL;
>        break;
> 
> 
> With these changes in place, regular gui app termination works well  
> with gdbserver --multi/remote-extended on Windows XP.
> 
> Best regards
> 
> Rolf
> 
> 



-- 
Pedro Alves