[ros-diffs] [ion] 23060: - Implement Safe Referencing (an internal method for referencing objects when race conditions are possible) - Implement two Vista APIs and export them: ObIsKernelHandle and ObDeleteObjectDeferDelete. ZOMG! Vista APIs in the kernel!

Author: ion
Date: Fri Jul 14 19:26:19 2006
New Revision: 23060

URL: http://svn.reactos.org/svn/reactos?rev=23060&view=rev
Log:
- Implement Safe Referencing (an internal method for referencing objects when race
conditions are possible)
- Implement two Vista APIs and export them: ObIsKernelHandle and
ObDeleteObjectDeferDelete. ZOMG! Vista APIs in the kernel!

Modified:
    trunk/reactos/ntoskrnl/ntoskrnl.def
    trunk/reactos/ntoskrnl/ob/obhandle.c
    trunk/reactos/ntoskrnl/ob/obref.c

Modified: trunk/reactos/ntoskrnl/ntoskrnl.def
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ntoskrnl.def?rev=…
==============================================================================
--- trunk/reactos/ntoskrnl/ntoskrnl.def (original)
+++ trunk/reactos/ntoskrnl/ntoskrnl.def Fri Jul 14 19:26:19 2006
@@ -841,12 +841,14 @@
 ObCreateObject@36
 ObCreateObjectType@16
 ObDereferenceObject@4
+ObDereferenceObjectDeferDelete@4
 ObDereferenceSecurityDescriptor@8
 @ObfDereferenceObject@4
 ObFindHandleForObject@20
 @ObfReferenceObject@4
 ObGetObjectSecurity@12
 ObInsertObject@24
+ObIsKernelHandle@4
 ObLogSecurityDescriptor@12
 ObMakeTemporaryObject@4
 ObOpenObjectByName@28

Modified: trunk/reactos/ntoskrnl/ob/obhandle.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ob/obhandle.c?rev…
==============================================================================
--- trunk/reactos/ntoskrnl/ob/obhandle.c (original)
+++ trunk/reactos/ntoskrnl/ob/obhandle.c Fri Jul 14 19:26:19 2006
@@ -2155,4 +2155,14 @@
     ObDereferenceObject(SourceProcess);
     return Status;
 }
+
+#undef ObIsKernelHandle
+BOOLEAN
+NTAPI
+ObIsKernelHandle(IN HANDLE Handle)
+{
+    /* We know we're kernel mode, so just check for the kernel handle flag */
+    return (BOOLEAN)((ULONG_PTR)Handle & KERNEL_HANDLE_FLAG);
+}
+
 /* EOF */

Modified: trunk/reactos/ntoskrnl/ob/obref.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ob/obref.c?rev=23…
==============================================================================
--- trunk/reactos/ntoskrnl/ob/obref.c (original)
+++ trunk/reactos/ntoskrnl/ob/obref.c Fri Jul 14 19:26:19 2006
@@ -17,6 +17,37 @@
 
 /* PRIVATE FUNCTIONS *********************************************************/
 
+BOOLEAN
+FASTCALL
+ObReferenceObjectSafe(IN PVOID Object)
+{
+    POBJECT_HEADER ObjectHeader;
+    LONG OldValue, NewValue;
+
+    /* Get the object header */
+    ObjectHeader = OBJECT_TO_OBJECT_HEADER(Object);
+
+    /* Get the current reference count and fail if it's zero */
+    OldValue = ObjectHeader->PointerCount;
+    if (!OldValue) return FALSE;
+
+    /* Start reference loop */
+    do
+    {
+        /* Increase the reference count */
+        NewValue = InterlockedCompareExchange(&ObjectHeader->PointerCount,
+                                              OldValue + 1,
+                                              OldValue);
+        if (OldValue == NewValue) return TRUE;
+
+        /* Keep looping */
+        OldValue = NewValue;
+    } while (OldValue);
+
+    /* If we got here, then the reference count is now 0 */
+    return FALSE;
+}
+
 VOID
 NTAPI
 ObpDeferObjectDeletion(IN PVOID Object)
@@ -129,7 +160,6 @@
     /* Get the object and count */
     Object = (PVOID)(Value &~ MAX_FAST_REFS);
     Count = Value & MAX_FAST_REFS;
-    DPRINT("Ref: %p\n", Object);
 
     /* Check if the reference count is over 1 */
     if (Count > 1) return Object;
@@ -172,7 +202,6 @@
     ULONG_PTR Value, NewValue;
 
     /* Sanity checks */
-    DPRINT("DeRef: %p\n", Object);
     ASSERT(Object);
     ASSERT(!(((ULONG_PTR)Object) & MAX_FAST_REFS));
 
@@ -287,10 +316,19 @@
     }
 }
 
-#ifdef ObDereferenceObject
+VOID
+NTAPI
+ObDereferenceObjectDeferDelete(IN PVOID Object)
+{
+    /* Check whether the object can now be deleted. */
+    if (!(InterlockedDecrement(&OBJECT_TO_OBJECT_HEADER(Object)->PointerCount)))
+    {
+        /* Add us to the deferred deletion list */
+        ObpDeferObjectDeletion(Object);
+    }
+}
+
 #undef ObDereferenceObject
-#endif
-
 VOID
 NTAPI
 ObDereferenceObject(IN PVOID Object)