Re: [PATCH] run > file for win32

[Pierre Muller <muller at cerbere dot u-strasbg dot fr>]

At 03:39 16/02/2002 , vous avez écrit:
>I've just adapted some patches from Tak Ota to win32-nat.c.
>
>Tak's patch didn't seem to be complete but the concept was so nice that
>I took some time in the last few days and finished things.
>
>The result is that you can use shell meta characters in gdb now, so
>things like 'run < foo > bar' now work.
>
>Since this is a departure from previous behavior, I turned this is off
>by default.  I added a 'set shell' command to control whether it is used
>or not.

Christopher, 
after examining your patch, I think there is a mistake inside.

Your patch uses a shell to start the debuggee and thus uses the flag
DEBUG_PROCESS instead of DEBUG_ONLY_THIS_PROCESS.

This means that you need to sort the events and only handle the events of the 
the second process created.

  First question: 
   - is it sure that the shell will never call any process before 
running the executable that it has as argument?

To sort the events and only handles those of the process that you want to debug you use
saw_create variable.

But this variable is incremented each time a process is run.

   Starting value is -1
    shell starts value is 0
    debuggee starts value is 1 so the events are handled, here its OK.
but if the debuggee starts another process then saw_create is incremented past 1 and
no event is recorded anymore => the program is stuck....

The following patch seems to overcome this bug.


2002-01-08  Pierre Muller  <muller@ics.u-strasbg.fr>

         * win32-nat.c (main_process_id): New variable. Used to only handle the 
         events from the debuggee.
         (get_child_debug_event): Set main_process_id on the 
         CREATE_PROCESS_DEBUG_EVENT. 
         Use main_process_id to check if a given event should be handled 
         by the debugger.


Index: win32-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/win32-nat.c,v
retrieving revision 1.52
diff -u -p -r1.52 win32-nat.c
--- win32-nat.c 2002/02/19 08:49:41     1.52
+++ win32-nat.c 2002/02/20 09:52:33
@@ -124,6 +124,7 @@ static DEBUG_EVENT current_event;   /* The
  static HANDLE current_process_handle;  /* Currently executing process */
  static thread_info *current_thread;    /* Info on currently selected thread */
  static DWORD main_thread_id;   /* Thread ID of the main thread */
+static DWORD main_process_id;

  /* Counts of things. */
  static int exception_count = 0;
@@ -1122,9 +1123,9 @@ get_child_debug_event (int pid, struct t
                      (unsigned) current_event.dwProcessId,
                      (unsigned) current_event.dwThreadId,
                      "CREATE_THREAD_DEBUG_EVENT"));
-      if (saw_create != 1)
-       break;
-      /* Record the existence of this thread */
+     if ((saw_create < 1) || (current_event.dwProcessId != main_process_id))
+       break;
+     /* Record the existence of this thread */
        th = child_add_thread (current_event.dwThreadId,
                              current_event.u.CreateThread.hThread);
        if (info_verbose)
@@ -1139,8 +1140,9 @@ get_child_debug_event (int pid, struct t
                      (unsigned) current_event.dwProcessId,
                      (unsigned) current_event.dwThreadId,
                      "EXIT_THREAD_DEBUG_EVENT"));
-      if (saw_create != 1)
+      if ((saw_create < 1) || (current_event.dwProcessId != main_process_id))
         break;
+
        child_delete_thread (current_event.dwThreadId);
        th = &dummy_thread_info;
        break;
@@ -1159,6 +1161,7 @@ get_child_debug_event (int pid, struct t

        current_process_handle = current_event.u.CreateProcessInfo.hProcess;
        main_thread_id = current_event.dwThreadId;
+      main_process_id = current_event.dwProcessId;
        /* Add the main thread */
  #if 0
        th = child_add_thread (current_event.dwProcessId,
@@ -1174,7 +1177,7 @@ get_child_debug_event (int pid, struct t
                      (unsigned) current_event.dwProcessId,
                      (unsigned) current_event.dwThreadId,
                      "EXIT_PROCESS_DEBUG_EVENT"));
-      if (saw_create != 1)
+      if ((saw_create < 1) || (current_event.dwProcessId != main_process_id))
         break;
        ourstatus->kind = TARGET_WAITKIND_EXITED;
        ourstatus->value.integer = current_event.u.ExitProcess.dwExitCode;
@@ -1188,7 +1191,7 @@ get_child_debug_event (int pid, struct t
                      (unsigned) current_event.dwThreadId,
                      "LOAD_DLL_DEBUG_EVENT"));
        CloseHandle (current_event.u.LoadDll.hFile);
-      if (saw_create != 1)
+      if ((saw_create < 1) || (current_event.dwProcessId != main_process_id))
         break;
        catch_errors (handle_load_dll, NULL, (char *) "", RETURN_MASK_ALL);
        registers_changed ();    /* mark all regs invalid */
@@ -1202,7 +1205,7 @@ get_child_debug_event (int pid, struct t
                      (unsigned) current_event.dwProcessId,
                      (unsigned) current_event.dwThreadId,
                      "UNLOAD_DLL_DEBUG_EVENT"));
-      if (saw_create != 1)
+      if ((saw_create < 1) || (current_event.dwProcessId != main_process_id))
         break;
        catch_errors (handle_unload_dll, NULL, (char *) "", RETURN_MASK_ALL);
        registers_changed ();    /* mark all regs invalid */
@@ -1215,7 +1218,7 @@ get_child_debug_event (int pid, struct t
                      (unsigned) current_event.dwProcessId,
                      (unsigned) current_event.dwThreadId,
                      "EXCEPTION_DEBUG_EVENT"));
-      if (saw_create != 1)
+      if ((saw_create < 1) || (current_event.dwProcessId != main_process_id))
         break;
        if (handle_exception (ourstatus))
         retval = current_event.dwThreadId;
@@ -1226,14 +1229,14 @@ get_child_debug_event (int pid, struct t
                      (unsigned) current_event.dwProcessId,
                      (unsigned) current_event.dwThreadId,
                      "OUTPUT_DEBUG_STRING_EVENT"));
-      if (saw_create != 1)
+      if ((saw_create < 1) || (current_event.dwProcessId != main_process_id))
         break;
        if (handle_output_debug_string (ourstatus))
         retval = main_thread_id;
        break;

      default:
-      if (saw_create != 1)
+      if ((saw_create < 1) || (current_event.dwProcessId != main_process_id))
         break;
        printf_unfiltered ("gdb: kernel event for pid=%ld tid=%ld\n",
                          (DWORD) current_event.dwProcessId,
@@ -1243,7 +1246,7 @@ get_child_debug_event (int pid, struct t
        break;
      }

-  if (!retval || saw_create != 1)
+  if (!retval)
      CHECK (child_continue (continue_status, -1));
    else
      {



Pierre Muller
Institut Charles Sadron
6,rue Boussingault
F 67083 STRASBOURG CEDEX (France)
mailto:muller@ics.u-strasbg.fr
Phone : (33)-3-88-41-40-07  Fax : (33)-3-88-41-40-99