Changeset 92017 in vbox for trunk/src/VBox/HostServices/SharedClipboard

Timestamp:

Oct 24, 2021 12:42:46 PM (3 years ago)

Author:

vboxsync

Message:

SharedClipboard: Corrected another pvData assertion preventing zero byte replies from getting thru in the VBOX_SHCL_GUEST_FN_DATA_WRITE path, causing waiting host clipboard code to get stuck waiting/timeout. Introduced in r135860, possibly by accident and probably not help by zero documentation around ShClSvcGuestDataSignal at that time. Made the code signal the waiter even if we fail to duplicate the data. bugref:10094

File:

• trunk/src/VBox/HostServices/SharedClipboard/VBoxSharedClipboardSvc.cpp (modified) (1 diff)

trunk/src/VBox/HostServices/SharedClipboard/VBoxSharedClipboardSvc.cpp

@@ -1341 +1341 @@
  *
  * @returns VBox status code. Returns VERR_NOT_FOUND when related event ID was not found.
- * @param   pClient             Client the guest clipboard data was received for.
- * @param   pCmdCtx             Client command context to use.
+ * @param   pClient             Client the guest clipboard data was received from.
+ * @param   pCmdCtx             Client command context.
  * @param   uFormat             Clipboard format of data received.
- * @param   pvData              Pointer to clipboard data received.
+ * @param   pvData              Pointer to clipboard data received.  This can be
+ *                              NULL if @a cbData is zero.
  * @param   cbData              Size (in bytes) of clipboard data received.
- */
-int ShClSvcGuestDataSignal(PSHCLCLIENT pClient, PSHCLCLIENTCMDCTX pCmdCtx,
-                           SHCLFORMAT uFormat, void *pvData, uint32_t cbData)
-{
+ *                              This can be zero.
+ */
+int ShClSvcGuestDataSignal(PSHCLCLIENT pClient, PSHCLCLIENTCMDCTX pCmdCtx, SHCLFORMAT uFormat, void *pvData, uint32_t cbData)
+{
+    LogFlowFuncEnter();
+    RT_NOREF(uFormat);
+
+    /*
+     * Validate intput.
+     */
     AssertPtrReturn(pClient, VERR_INVALID_POINTER);
     AssertPtrReturn(pCmdCtx, VERR_INVALID_POINTER);
-    AssertPtrReturn(pvData,  VERR_INVALID_POINTER);
-
-    RT_NOREF(uFormat);
-
-    LogFlowFuncEnter();
+    if (cbData > 0)
+        AssertPtrReturn(pvData, VERR_INVALID_POINTER);
 
     const SHCLEVENTID idEvent = VBOX_SHCL_CONTEXTID_GET_EVENT(pCmdCtx->uContextID);
-
-    AssertMsgReturn(idEvent != NIL_SHCLEVENTID,
-                    ("Event %RU64 empty within supplied context ID\n", idEvent), VERR_WRONG_ORDER);
-#ifdef VBOX_STRICT
-    AssertMsgReturn(ShClEventGet(&pClient->EventSrc, idEvent) != NULL,
-                    ("Event %RU64 not found, even if context ID was around\n", idEvent), VERR_NOT_FOUND);
-#endif
-
+    AssertMsgReturn(idEvent != NIL_SHCLEVENTID, ("NIL event in context ID %#RX64\n", pCmdCtx->uContextID), VERR_WRONG_ORDER);
+    AssertMsg(ShClEventGet(&pClient->EventSrc, idEvent) != NULL, ("Event %#x not found\n", idEvent));
+
+    /*
+     * Make a copy of the data so we can attach it to the signal.
+     *
+     * Note! We still signal the waiter should we run out of memory,
+     *       because otherwise it will be stuck waiting.
+     */
     int rc = VINF_SUCCESS;
-
     PSHCLEVENTPAYLOAD pPayload = NULL;
-    if (cbData)
+    if (cbData > 0)
         rc = ShClPayloadAlloc(idEvent, pvData, cbData, &pPayload);
 
-    if (RT_SUCCESS(rc))
-    {
-        RTCritSectEnter(&pClient->CritSect);
-        rc = ShClEventSignal(&pClient->EventSrc, idEvent, pPayload);
-        RTCritSectLeave(&pClient->CritSect);
-        if (RT_FAILURE(rc))
-            ShClPayloadFree(pPayload);
-
-        /* No one holding a reference to the event anymore? Unregister it. */
-        if (ShClEventGetRefs(&pClient->EventSrc, idEvent) == 0)
-        {
-            int rc2 = ShClEventUnregister(&pClient->EventSrc, idEvent);
-            if (RT_SUCCESS(rc))
-                rc = rc2;
-        }
-    }
-
-    if (RT_FAILURE(rc))
-        LogRel(("Shared Clipboard: Signalling of guest clipboard data to the host failed with %Rrc\n", rc));
+    /*
+     * Signal the event.
+     */
+    RTCritSectEnter(&pClient->CritSect);
+    int rc2 = ShClEventSignal(&pClient->EventSrc, idEvent, pPayload);
+    RTCritSectLeave(&pClient->CritSect);
+    if (RT_FAILURE(rc2))
+    {
+        rc = rc2;
+        ShClPayloadFree(pPayload);
+        LogRel(("Shared Clipboard: Signalling of guest clipboard data to the host failed: %Rrc\n", rc));
+    }
+
+    /*
+     * No one holding a reference to the event anymore? Unregister it.
+     */
+    /** @todo r=bird: This isn't how reference counting is supposed to be
+     *        implemented, is it now? */
+    if (ShClEventGetRefs(&pClient->EventSrc, idEvent) == 0)
+    {
+        rc2 = ShClEventUnregister(&pClient->EventSrc, idEvent);
+        if (RT_SUCCESS(rc))
+            rc = rc2;
+    }
 
     LogFlowFuncLeaveRC(rc);