Re: error_start patch

[Chris Faylor <cgf at cygnus dot com>]

This is very interesting but I'm wondering why you use GetEnvironmentStrings
rather than GetEnvironmentVariable below.

cgf

On Mon, May 22, 2000 at 09:24:02PM +0400, Egor Duda wrote:
>Hi!
>
>  Below  is  a  patch  to prevent cygwin's JIT debugger (specified via
>'error_start')   from   being   spawned   recursively,  in  case  when
>debugger throws exception itself. It also allows to notify the debugee
>that  we've    done    with   debugging   and  it  can  exit in peace.
>debugger can post event named
>
>"cygwin_error_start_event_<debugee_win32_pid>"
>
>instead of
>
>(gdb) set keep_looping=0
>(gdb) c
>
>----------------------------------------------------------------------------
>2000-05-22  Egor Duda <deo@logos-m.ru>
>
>        * exceptions.cc (try_to_debug): prevent recursive spawning of JIT
>        debugger.
>        * exceptions.cc (try_to_debug): treat  special event from debugger
>        as command to continue.
>
>Index: cygwin/exceptions.cc
>===================================================================
>RCS file: /home/duda_admin/cvs-mirror/src/winsup/cygwin/exceptions.cc,v
>retrieving revision 1.17
>diff -c -2 -r1.17 exceptions.cc
>*** cygwin/exceptions.cc        2000/05/20 05:52:33     1.17
>--- cygwin/exceptions.cc        2000/05/22 16:55:40
>***************
>*** 301,304 ****
>--- 301,306 ----
>  static int NO_COPY keep_looping = 0;
>  
>+ #define TIME_TO_WAIT_FOR_DEBUGGER 10000
>+ 
>  extern "C" int
>  try_to_debug ()
>***************
>*** 330,333 ****
>--- 332,350 ----
>    ReleaseMutex (title_mutex);
>  
>+   /* prevent recursive exception handling */
>+   char* rawenv = GetEnvironmentStrings () ;
>+   for ( char* p = rawenv; *p != '\0'; p = strchr (p, '\0') + 1 )
>+     { 
>+       if (strncmp ( p, "CYGWIN=", sizeof("CYGWIN=") - 1) == 0)
>+         {
>+           system_printf ( "%s", p);
>+           char* q = strstr ( p, "error_start" ) ;
>+           /* replace 'error_start=...' with '_rror_start=...' */
>+           if ( q ) *q = '_' ;
>+           SetEnvironmentVariable ( "CYGWIN", p+sizeof("CYGWIN=") ) ;
>+           break ;
>+         }
>+     }
>+ 
>    dbg = CreateProcess (NULL,
>                       debugger_command,
>***************
>*** 349,355 ****
>    else
>      {
>        keep_looping = 1;
>!       while (keep_looping)
>!       Sleep (10000);
>      }
>  
>--- 366,385 ----
>    else
>      {
>+       char event_name [ sizeof ( "cygwin_error_start_event" ) + 9 ];
>+       DWORD win32_pid = GetCurrentProcessId ();
>+       __small_sprintf ( event_name, "cygwin_error_start_event%x", win32_pid );
>+       HANDLE sync_with_dbg = CreateEvent ( NULL, TRUE, FALSE, event_name );
>        keep_looping = 1;
>!       while (keep_looping) 
>!         {
>!           if (sync_with_dbg == NULL)
>!             Sleep (TIME_TO_WAIT_FOR_DEBUGGER);
>!           else
>!             {
>!               if (WaitForSingleObject (sync_with_dbg,
>!                                        TIME_TO_WAIT_FOR_DEBUGGER) == WAIT_OBJECT_0)
>!                 break;
>!             }
>!          }
>      }
>
>----------------------------------------------------------------------------
>
>Egor.            mailto:deo@logos-m.ru ICQ 5165414 FidoNet 2:5020/496.19
>

-- 
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