Re: delete-process bug

[michael.cadilhac@lrde.org (Michaël Cadilhac)]

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storm@cua.dk (Kim F. Storm) writes:

> michael.cadilhac@lrde.org (Michaël Cadilhac) writes:
>
>> It seems  that the  guard we  put (#ifdef SIGCHLD)  was not  the right
>> thing to do, isn't it ?
>
> I promised Eli to shut up

Please don't  :-)

> but it once again occurred to me that the sigchld_handler is only
> called _IF_ SIGCHLD is defined.

> Since the sigchld_handler is only installed if SIGCHLD is defined,
> it will only ever be called (to cleanup deleted_pid_list) if
> SIGCHLD is defined.

> So it still seems wrong to put anything on deleted_pid_list unless
> SIGCHLD is defined ...

> And sigchld_handler should be conditioned by #ifdef SIGCHLD.

Aaaand here comes the new new new (super better) new great patch
v3923.3 (beta 1) !


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Index: src/process.c
===================================================================
RCS file: /sources/emacs/emacs/src/process.c,v
retrieving revision 1.481
diff -c -r1.481 process.c
*** src/process.c	8 May 2006 05:19:42 -0000	1.481
--- src/process.c	30 May 2006 12:35:10 -0000
***************
*** 778,783 ****
--- 778,793 ----
    return proc;
  }
  
+ 
+ #ifdef SIGCHLD
+ /* Fdelete_process promises to immediately forget about the process, but in
+    reality, Emacs needs to remember those processes until they have been
+    treated by sigchld_handler; otherwise this handler would consider the
+    process as being synchronous and say that the synchronous process is
+    dead.  */
+ static Lisp_Object deleted_pid_list;
+ #endif
+ 
  DEFUN ("delete-process", Fdelete_process, Sdelete_process, 1, 1, 0,
         doc: /* Delete PROCESS: kill it and forget about it immediately.
  PROCESS may be a process, a buffer, the name of a process or buffer, or
***************
*** 799,810 ****
      }
    else if (XINT (p->infd) >= 0)
      {
!       Fkill_process (process, Qnil);
!       /* Do this now, since remove_process will make sigchld_handler do nothing.  */
!       p->status
! 	= Fcons (Qsignal, Fcons (make_number (SIGKILL), Qnil));
!       XSETINT (p->tick, ++process_tick);
!       status_notify (p);
      }
    remove_process (process);
    return Qnil;
--- 809,839 ----
      }
    else if (XINT (p->infd) >= 0)
      {
! #ifdef SIGCHLD
!       Lisp_Object symbol;
! 
!       /* No problem storing the pid here, as it is still in Vprocess_alist.  */
!       deleted_pid_list = Fcons (make_fixnum_or_float (p->pid),
! 				/* GC treated elements set to nil.  */
! 				Fdelq (Qnil, deleted_pid_list));
!       /* If the process has already signaled, remove it from the list.  */
!       if (p->raw_status_new)
! 	update_status (p);
!       symbol = p->status;
!       if (CONSP (p->status))
! 	symbol = XCAR (p->status);
!       if (EQ (symbol, Qsignal) || EQ (symbol, Qexit))
! 	Fdelete (make_fixnum_or_float (p->pid), deleted_pid_list);
!       else
! #endif
! 	{
! 	  Fkill_process (process, Qnil);
! 	  /* Do this now, since remove_process will make sigchld_handler do nothing.  */
! 	  p->status
! 	    = Fcons (Qsignal, Fcons (make_number (SIGKILL), Qnil));
! 	  XSETINT (p->tick, ++process_tick);
! 	  status_notify (p);
! 	}
      }
    remove_process (process);
    return Qnil;
***************
*** 6316,6321 ****
--- 6345,6351 ----
     ** Malloc WARNING: This should never call malloc either directly or
     indirectly; if it does, that is a bug  */
  
+ #ifdef SIGCHLD
  SIGTYPE
  sigchld_handler (signo)
       int signo;
***************
*** 6373,6378 ****
--- 6403,6417 ----
  
        /* Find the process that signaled us, and record its status.  */
  
+       /* The process can have been deleted by Fdelete_process.  */
+       tail = Fmember (make_fixnum_or_float (pid), deleted_pid_list);
+       if (!NILP (tail))
+ 	{
+ 	  Fsetcar (tail, Qnil);
+ 	  goto sigchld_end_of_loop;
+ 	}
+ 
+       /* Otherwise, if it is asynchronous, it is in Vprocess_alist.  */
        p = 0;
        for (tail = Vprocess_alist; GC_CONSP (tail); tail = XCDR (tail))
  	{
***************
*** 6424,6431 ****
  	    EMACS_SET_SECS_USECS (*input_available_clear_time, 0, 0);
  	}
  
! 	/* There was no asynchronous process found for that id.  Check
! 	   if we have a synchronous process.  */
        else
  	{
  	  synch_process_alive = 0;
--- 6463,6470 ----
  	    EMACS_SET_SECS_USECS (*input_available_clear_time, 0, 0);
  	}
  
!       /* There was no asynchronous process found for that pid: we have
! 	 a synchronous process.  */
        else
  	{
  	  synch_process_alive = 0;
***************
*** 6442,6447 ****
--- 6481,6490 ----
  	    EMACS_SET_SECS_USECS (*input_available_clear_time, 0, 0);
  	}
  
+ 
+     sigchld_end_of_loop:
+       ;
+ 
        /* On some systems, we must return right away.
  	 If any more processes want to signal us, we will
  	 get another signal.
***************
*** 6458,6463 ****
--- 6501,6507 ----
  #endif /* USG, but not HPUX with WNOHANG */
      }
  }
+ #endif /* SIGCHLD */
  \f
  
  static Lisp_Object
***************
*** 6843,6848 ****
--- 6887,6895 ----
    FD_SET (0, &input_wait_mask);
  
    Vprocess_alist = Qnil;
+ #ifdef SIGCHLD
+   deleted_pid_list = Qnil;
+ #endif
    for (i = 0; i < MAXDESC; i++)
      {
        chan_process[i] = Qnil;
***************
*** 6981,6986 ****
--- 7028,7036 ----
    staticpro (&Qlast_nonmenu_event);
  
    staticpro (&Vprocess_alist);
+ #ifdef SIGCHLD
+   staticpro (&deleted_pid_list);
+ #endif
  
    DEFVAR_BOOL ("delete-exited-processes", &delete_exited_processes,
  	       doc: /* *Non-nil means delete processes immediately when they exit.

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> Sorry that I'm going round in circles (perhaps my brain in an
> infinite loop :-)

No problem. Hope you will not need a KILL signal in your brain, for
the sake of your (?) CHLD.

-- 
 |      Michaël `Micha' Cadilhac   |  Mieux vaut se taire                   |
 |         Epita/LRDE Promo 2007   |   Que de parler trop fort.             |
 | http://www.lrde.org/~cadilh_m   |           -- As de trèfle              |
 `--  -   JID: micha@amessage.be --'                                   -  --'

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