- Reapply 35812:

- RtlDispatchException: Call vectored exception handlers before doing anything else
- KiUserExceptionDispatcher: Call RtlDispatchException directly as it now takes care of vectored handling
- Rename RtlpExecuteVectoredExceptionHandlers to RtlCallVectoredExceptionHandlers, and fix return type
- References: "New Vectored Exception Handling in Windows XP" by Matt Pietrek
- New in this revision: Only call vectored handlers in user mode, as there is no such thing in kernel mode

svn path=/trunk/; revision=37137

reactos/dll/ntdll/dispatch/dispatch.c

@@ -15,10 +15,6 @@
 
 typedef NTSTATUS (NTAPI *USER_CALL)(PVOID Argument, ULONG ArgumentLength);
 
-EXCEPTION_DISPOSITION NTAPI
-RtlpExecuteVectoredExceptionHandlers(IN PEXCEPTION_RECORD  ExceptionRecord,
-                                     IN PCONTEXT  Context);
-
 /* FUNCTIONS ****************************************************************/
 
 /*
@@ -32,18 +28,9 @@ KiUserExceptionDispatcher(PEXCEPTION_RECORD ExceptionRecord,
     EXCEPTION_RECORD NestedExceptionRecord;
     NTSTATUS Status;
 
-    /* call the vectored exception handlers */
-    if(RtlpExecuteVectoredExceptionHandlers(ExceptionRecord,
-                                            Context) != ExceptionContinueExecution)
-    {
-        goto ContinueExecution;
-    }
-    else
-    {
     /* Dispatch the exception and check the result */
-        if(RtlDispatchException(ExceptionRecord, Context))
+    if (RtlDispatchException(ExceptionRecord, Context))
     {
-ContinueExecution:
         /* Continue executing */
         Status = NtContinue(Context, FALSE);
     }
@@ -52,7 +39,6 @@ ContinueExecution:
         /* Raise an exception */
         Status = NtRaiseException(ExceptionRecord, Context, FALSE);
     }
-    }
 
     /* Setup the Exception record */
     NestedExceptionRecord.ExceptionCode = Status;

reactos/dll/ntdll/dispatch/i386/dispatch.S

@@ -183,52 +183,22 @@ _KiRaiseUserExceptionDispatcher@0:
 .globl _KiUserExceptionDispatcher@8
 _KiUserExceptionDispatcher@8:
 
-    /* clear the direct flag 
+    /* Clear direction flag */
-     * text from bug 2279
-     * if it not clear it means that if an exception occurs while
-     * the direction flag is set (typically inside memmove), the 
-     * exception handlers will be called with the direction flag still
-     * set.  The Windows x86-32 and x86-64 ABI requires that the 
-     * direction flag be Calling memset() with a compile-time constant 
-     * size on both GCC and MSVC will result in inlining a "rep stosd" 
-     * instruction.  Because of the ABI, they will assume that the 
-     * direction flag is clear and not emit a "cld" instruction. 
-     * Using memset() in an exception handler therefore will 
-     * corrupt memory if the exception occurred during a reverse copy 
-     * such as a forward overlapping memmove().
-     *
-     * For reliability and ease of debugging, please add "cld" to the beginning of
-     * KiUserExceptionDispatcher.  Note that the same will be true of x86-64 whenever
-     * that happens.  This does not affect continuing execution; the CONTEXT of the
-     * exception has the direction flag set and will be restored upon NtContinue. 
-     * KiUserApcDispatcher and KiUserCallbackDispatcher need to be evaluated for this
-     * issue.
-     */
-     
     cld
 
     /* Save the Context and Exception Records */
     mov ecx, [esp+4]
     mov ebx, [esp]
 
-    /* Call the vectored exception handler */
+    /* Dispatch the exception */
     push ecx
     push ebx
-    call _RtlpExecuteVectoredExceptionHandlers@8
-
-    /* Check for success */
-    or al, al
-    jnz ContinueExecution
-
-    /* Dispatch the exception */
-    sub esp, 8
     call _RtlDispatchException@8
 
     /* Check for success */
     or al, al
     jz RaiseException
 
-ContinueExecution:
     /* Pop off the records */
     pop ebx
     pop ecx

reactos/lib/rtl/i386/except.c

@@ -74,6 +74,17 @@ RtlDispatchException(IN PEXCEPTION_RECORD ExceptionRecord,
     ULONG_PTR StackLow, StackHigh;
     ULONG_PTR RegistrationFrameEnd;
 
+    /* Perform vectored exception handling if we are in user mode */
+    if (RtlpGetMode() != KernelMode)
+    {
+        /* Call any registered vectored handlers */
+        if (RtlCallVectoredExceptionHandlers(ExceptionRecord, Context))
+        {
+            /* Exception handled, continue execution */
+            return TRUE;
+        }
+    }
+
     /* Get the current stack limits and registration frame */
     RtlpGetStackLimits(&StackLow, &StackHigh);
     RegistrationFrame = RtlpGetExceptionList();

reactos/lib/rtl/rtlp.h

@@ -37,6 +37,13 @@ VOID
 NTAPI
 RtlpSetExceptionList(PEXCEPTION_REGISTRATION_RECORD NewExceptionList);
 
+BOOLEAN
+NTAPI
+RtlCallVectoredExceptionHandlers(
+    IN PEXCEPTION_RECORD ExceptionRecord,
+    IN PCONTEXT Context
+);
+
 typedef struct _DISPATCHER_CONTEXT
 {
     PEXCEPTION_REGISTRATION_RECORD RegistrationPointer;

reactos/lib/rtl/vectoreh.c

@@ -28,8 +28,9 @@ typedef struct _RTL_VECTORED_EXCEPTION_HANDLER
 
 /* FUNCTIONS ***************************************************************/
 
-EXCEPTION_DISPOSITION NTAPI
+BOOLEAN
-RtlpExecuteVectoredExceptionHandlers(IN PEXCEPTION_RECORD  ExceptionRecord,
+NTAPI
+RtlCallVectoredExceptionHandlers(IN PEXCEPTION_RECORD  ExceptionRecord,
                                  IN PCONTEXT  Context)
 {
   PLIST_ENTRY CurrentEntry;
@@ -55,7 +56,7 @@ RtlpExecuteVectoredExceptionHandlers(IN PEXCEPTION_RECORD  ExceptionRecord,
 
       if(VectoredHandler(&ExceptionInfo) == EXCEPTION_CONTINUE_EXECUTION)
       {
-        return ExceptionContinueSearch;
+        return TRUE;
       }
 
       RtlEnterCriticalSection(&RtlpVectoredExceptionLock);
@@ -63,7 +64,7 @@ RtlpExecuteVectoredExceptionHandlers(IN PEXCEPTION_RECORD  ExceptionRecord,
     RtlLeaveCriticalSection(&RtlpVectoredExceptionLock);
   }
 
-  return ExceptionContinueExecution;
+  return FALSE;
 }
 
 VOID