[ion] 25608: - Fix reference count bugs in executive timer implementation. - Don't modify status when failing due to an access fault (NT doesn't!). - Do parameter checks before bothering with expensive SEHing.

Author: ion
Date: Wed Jan 24 02:10:13 2007
New Revision: 25608

URL: http://svn.reactos.org/svn/reactos?rev=25608&view=rev
Log:
- Fix reference count bugs in executive timer implementation.
- Don't modify status when failing due to an access fault (NT doesn't!).
- Do parameter checks before bothering with expensive SEHing.

Modified:
    trunk/reactos/ntoskrnl/ex/timer.c

Modified: trunk/reactos/ntoskrnl/ex/timer.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ex/timer.c?rev=256...
==============================================================================
--- trunk/reactos/ntoskrnl/ex/timer.c (original)
+++ trunk/reactos/ntoskrnl/ex/timer.c Wed Jan 24 02:10:13 2007
@@ -79,7 +79,7 @@
             /* Cancel the timer and remove its DPC and APC */
             KeCancelTimer(&Timer->KeTimer);
             KeRemoveQueueDpc(&Timer->TimerDpc);
-            if (KeRemoveQueueApc(&Timer->TimerApc)) DerefsToDo = 2;
+            if (KeRemoveQueueApc(&Timer->TimerApc)) DerefsToDo++;

/* Add another dereference to do */
             DerefsToDo++;
@@ -101,7 +101,6 @@

/* Release lock and return */
     KeReleaseSpinLock(&Thread->ActiveTimerListLock, OldIrql);
-    return;
 }

VOID
@@ -200,7 +199,7 @@

/* Disable it */
             Timer->ApcAssociated = FALSE;
-            DerefsToDo = 2;
+            DerefsToDo++;
         }
     }
     else
@@ -306,7 +305,7 @@
             /* Cancel the Timer */
             KeCancelTimer(&Timer->KeTimer);
             KeRemoveQueueDpc(&Timer->TimerDpc);
-            if (KeRemoveQueueApc(&Timer->TimerApc)) DerefsToDo = 2;
+            if (KeRemoveQueueApc(&Timer->TimerApc)) DerefsToDo++;
             DerefsToDo++;
         }
         else
@@ -351,7 +350,7 @@
             }
             _SEH_EXCEPT(_SEH_ExSystemExceptionFilter)
             {
-                Status = _SEH_GetExceptionCode();
+
             }
             _SEH_END;
         }
@@ -374,6 +373,14 @@
     NTSTATUS Status = STATUS_SUCCESS;
     PAGED_CODE();

+    /* Check for correct timer type */
+    if ((TimerType != NotificationTimer) &&
+        (TimerType != SynchronizationTimer))
+    {
+        /* Fail */
+        return STATUS_INVALID_PARAMETER_4;
+    }
+
     /* Check Parameter Validity */
     if (PreviousMode != KernelMode)
     {
@@ -387,12 +394,6 @@
         }
         _SEH_END;
         if(!NT_SUCCESS(Status)) return Status;
-    }
-
-    /* Check for correct timer type */
-    if ((TimerType != NotificationTimer) && (TimerType != SynchronizationTimer))
-    {
-        return STATUS_INVALID_PARAMETER_4;
     }

/* Create the Object */
@@ -427,16 +428,20 @@
                                 NULL,
                                 &hTimer);

-        /* Make sure it's safe to write to the handle */
-        _SEH_TRY
-        {
-            *TimerHandle = hTimer;
-        }
-        _SEH_EXCEPT(_SEH_ExSystemExceptionFilter)
-        {
-            Status = _SEH_GetExceptionCode();
-        }
-        _SEH_END;
+        /* Check for success */
+        if (NT_SUCCESS(Status))
+        {
+            /* Make sure it's safe to write to the handle */
+            _SEH_TRY
+            {
+                *TimerHandle = hTimer;
+            }
+            _SEH_EXCEPT(_SEH_ExSystemExceptionFilter)
+            {
+
+            }
+            _SEH_END;
+        }
     }

/* Return to Caller */
@@ -486,7 +491,7 @@
         }
         _SEH_EXCEPT(_SEH_ExSystemExceptionFilter)
         {
-            Status = _SEH_GetExceptionCode();
+
         }
         _SEH_END;
     }
@@ -578,13 +583,16 @@
     NTSTATUS Status = STATUS_SUCCESS;
     PAGED_CODE();

+    /* Check for a valid Period */
+    if (Period < 0) return STATUS_INVALID_PARAMETER_6;
+
     /* Check Parameter Validity */
     if (PreviousMode != KernelMode)
     {
         _SEH_TRY
         {
             TimerDueTime = ProbeForReadLargeInteger(DueTime);
-            if(PreviousState) ProbeForWriteBoolean(PreviousState);
+            if (PreviousState) ProbeForWriteBoolean(PreviousState);
         }
         _SEH_EXCEPT(_SEH_ExSystemExceptionFilter)
         {
@@ -593,9 +601,6 @@
         _SEH_END;
         if(!NT_SUCCESS(Status)) return Status;
     }
-
-    /* Check for a valid Period */
-    if (Period < 0) return STATUS_INVALID_PARAMETER_6;

/* Get the Timer Object */
     Status = ObReferenceObjectByHandle(TimerHandle,
@@ -640,7 +645,7 @@
             /* Cancel the Timer */
             KeCancelTimer(&Timer->KeTimer);
             KeRemoveQueueDpc(&Timer->TimerDpc);
-            if (KeRemoveQueueApc(&Timer->TimerApc)) DerefsToDo = 2;
+            if (KeRemoveQueueApc(&Timer->TimerApc)) DerefsToDo++;
             DerefsToDo++;
         }
         else
@@ -653,6 +658,7 @@
         State = KeReadStateTimer(&Timer->KeTimer);

/* Handle Wake Timers */
+        Timer->WakeTimer = WakeTimer;
         KeAcquireSpinLockAtDpcLevel(&ExpWakeListLock);
         if ((WakeTimer) && !(Timer->WakeTimerListEntry.Flink))
         {
@@ -713,7 +719,6 @@
             }
             _SEH_EXCEPT(_SEH_ExSystemExceptionFilter)
             {
-                Status = _SEH_GetExceptionCode();
             }
             _SEH_END;
         }