Changeset 36744 in vbox for trunk/src/VBox/Additions/common/VBoxService

Timestamp:

Apr 20, 2011 10:05:09 AM (14 years ago)

Author:

vboxsync

Message:

VBoxService/PipeBuf: Fixed deadlocks, added function for pipe peeking.

Location:

trunk/src/VBox/Additions/common/VBoxService

Files:

• VBoxServicePipeBuf.cpp (modified) (3 diffs)
• VBoxServicePipeBuf.h (modified) (1 diff)

trunk/src/VBox/Additions/common/VBoxService/VBoxServicePipeBuf.cpp

@@ -114 +114 @@
         }
         rc = RTCritSectLeave(&pBuf->CritSect);
+    }
+    return rc;
+}
+
+
+int VBoxServicePipeBufPeek(PVBOXSERVICECTRLEXECPIPEBUF pBuf,
+                           uint8_t *pbBuffer, uint32_t cbBuffer,
+                           uint32_t cbOffset,
+                           uint32_t *pcbRead, uint32_t *pcbLeft)
+{
+    AssertPtrReturn(pBuf, VERR_INVALID_POINTER);
+    AssertPtrReturn(pbBuffer, VERR_INVALID_POINTER);
+    AssertReturn(cbBuffer, VERR_INVALID_PARAMETER);
+
+    int rc = RTCritSectEnter(&pBuf->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        Assert(pBuf->cbSize >= pBuf->cbOffset);
+        if (cbOffset > pBuf->cbSize)
+            cbOffset = pBuf->cbSize;
+        uint32_t cbToRead = pBuf->cbSize - cbOffset;
+        if (cbToRead > cbBuffer)
+            cbToRead = cbBuffer;
+        if (cbToRead)
+        {
+            memcpy(pbBuffer, pBuf->pbData + cbOffset, cbToRead);
+            pbBuffer[cbBuffer - 1] = '\0';
+        }
+        if (pcbRead)
+            *pcbRead = cbToRead;
+        if (pcbLeft)
+            *pcbLeft = pBuf->cbSize - (cbOffset + cbToRead);
+
+        int rc2 = RTCritSectLeave(&pBuf->CritSect);
+        if (RT_SUCCESS(rc))
+            rc = rc2;
     }
     return rc;
@@ -222 +258 @@
                 RTSemEventSignal(pBuf->hEventSem);
             }
-            int rc2 = RTCritSectLeave(&pBuf->CritSect);
-            if (RT_SUCCESS(rc))
-                rc = rc2;
         }
         else
             rc = VERR_BAD_PIPE;
+
+        int rc2 = RTCritSectLeave(&pBuf->CritSect);
+        if (RT_SUCCESS(rc))
+            rc = rc2;
     }
     return rc;
@@ -377 +414 @@
 int VBoxServicePipeBufWaitForEvent(PVBOXSERVICECTRLEXECPIPEBUF pBuf, RTMSINTERVAL cMillies)
 {
-    int rc = RTCritSectEnter(&pBuf->CritSect);
-    if (RT_SUCCESS(rc))
-    {
-        rc = RTSemEventWait(pBuf->hEventSem, cMillies);
-        int rc2 = RTCritSectLeave(&pBuf->CritSect);
-        if (RT_SUCCESS(rc))
-            rc = rc2;
-    }
-    return rc;
+    AssertPtrReturn(pBuf, VERR_INVALID_POINTER);
+
+    /* Don't enter the critical section here; someone else could signal the event semaphore
+     * and this will deadlock then ... */
+    return RTSemEventWait(pBuf->hEventSem, cMillies);
 }
 

trunk/src/VBox/Additions/common/VBoxService/VBoxServicePipeBuf.h

@@ -24 +24 @@
 int  VBoxServicePipeBufRead(PVBOXSERVICECTRLEXECPIPEBUF pBuf,
                             uint8_t *pbBuffer, uint32_t cbBuffer, uint32_t *pcbToRead);
+int VBoxServicePipeBufPeek(PVBOXSERVICECTRLEXECPIPEBUF pBuf,
+                           uint8_t *pbBuffer, uint32_t cbBuffer,
+                           uint32_t cbOffset,
+                           uint32_t *pcbRead, uint32_t *pcbLeft);
 int  VBoxServicePipeBufWriteToBuf(PVBOXSERVICECTRLEXECPIPEBUF pBuf,
                                   uint8_t *pbData, uint32_t cbData, bool fPendingClose, uint32_t *pcbWritten);