Changeset 71950 in vbox for trunk/src/VBox

Timestamp:

Apr 20, 2018 9:31:06 PM (7 years ago)

Author:

vboxsync

Message:

socket.cpp: Windows polling fixes for problem where we got stuck returning RTPOLL_EVT_READ.

Location:

trunk/src/VBox/Runtime/r3

Files:

• socket.cpp (modified) (5 diffs)
• win/init-win.cpp (modified) (3 diffs)
• win/internal-r3-win.h (modified) (2 diffs)

trunk/src/VBox/Runtime/r3/socket.cpp

@@ -164 +164 @@
     uint32_t            fSubscribedEvts;
     /** Saved events which are only posted once and events harvested for
-     * sockets entetered multiple times into to a poll set. */
+     * sockets entered multiple times into to a poll set.   Imagine a scenario where
+     * you have a RTPOLL_EVT_READ entry and RTPOLL_EVT_ERROR entry.  The READ
+     * condition can be triggered between checking the READ entry and the ERROR
+     * entry, and we don't want to drop the READ, so we store it here and make sure
+     * the event is signalled.
+     *
+     * The RTPOLL_EVT_ERROR is inconsistenly sticky at the momemnt... */
     uint32_t            fEventsSaved;
-    /** Set if fEventsSaved contains harvested events. */
+    /** Set if fEventsSaved contains harvested events (used to avoid multiple
+     *  calls to rtSocketPollCheck on the same socket during rtSocketPollDone). */
     bool                fHarvestedEvents;
     /** Set if we're using the polling fallback. */
@@ -2843 +2850 @@
 
             pThis->fEventsSaved = fRetEvents |= pThis->fEventsSaved;
+            fRetEvents &= fEvents | RTPOLL_EVT_ERROR;
         }
         else
@@ -2957 +2965 @@
     {
         pThis->fPollEvts |= fEvents;
-        if (   fFinalEntry
-            && pThis->fSubscribedEvts != pThis->fPollEvts)
-        {
-            int rc = rtSocketPollUpdateEvents(pThis, pThis->fPollEvts);
-            if (RT_FAILURE(rc))
+        if (fFinalEntry)
+        {
+            if (pThis->fSubscribedEvts != pThis->fPollEvts)
             {
-                pThis->fPollEvts = 0;
-                fRetEvents       = UINT32_MAX;
+                /** @todo seems like there migth be a call to many here and that fPollEvts is
+                 *        totally unnecessary... (bird) */
+                int rc = rtSocketPollUpdateEvents(pThis, pThis->fPollEvts);
+                if (RT_FAILURE(rc))
+                {
+                    pThis->fPollEvts = 0;
+                    fRetEvents       = UINT32_MAX;
+                }
             }
+
+            /* Make sure we don't block when there are events pending relevant to an earlier poll set entry. */
+            if (pThis->fEventsSaved && !pThis->fPollFallback && g_pfnWSASetEvent && fRetEvents == 0)
+                g_pfnWSASetEvent(pThis->hEvent);
         }
     }
@@ -2977 +2993 @@
         {
 # ifdef RT_OS_WINDOWS
+            pThis->fEventsSaved    &= RTPOLL_EVT_ERROR;
+            pThis->fHarvestedEvents = false;
             rtSocketPollClearEventAndRestoreBlocking(pThis);
 # endif
             pThis->hPollSet = NIL_RTPOLLSET;
         }
+# ifdef RT_OS_WINDOWS
+        else
+            pThis->fHarvestedEvents = true;
+# endif
         ASMAtomicDecU32(&pThis->cUsers);
     }
@@ -3069 +3091 @@
     {
 # ifdef RT_OS_WINDOWS
-        pThis->fEventsSaved   &= RTPOLL_EVT_ERROR;
+        pThis->fEventsSaved    &= RTPOLL_EVT_ERROR;
         pThis->fHarvestedEvents = false;
         rtSocketPollClearEventAndRestoreBlocking(pThis);

trunk/src/VBox/Runtime/r3/win/init-win.cpp

@@ -103 +103 @@
 /** WSACloseEvent  */
 DECLHIDDEN(PFNWSACLOSEEVENT)                g_pfnWSACloseEvent = NULL;
+/** WSASetEvent */
+DECLHIDDEN(PFNWSASETEVENT)                  g_pfnWSASetEvent = NULL;
 /** WSAEventSelect   */
 DECLHIDDEN(PFNWSAEVENTSELECT)               g_pfnWSAEventSelect = NULL;
@@ -363 +365 @@
     g_pfnWSACreateEvent       = (decltype(g_pfnWSACreateEvent))     GetProcAddress(g_hModWinSock, "WSACreateEvent");
     g_pfnWSACloseEvent        = (decltype(g_pfnWSACloseEvent))      GetProcAddress(g_hModWinSock, "WSACloseEvent");
+    g_pfnWSASetEvent          = (decltype(g_pfnWSASetEvent))        GetProcAddress(g_hModWinSock, "WSASetEvent");
     g_pfnWSAEventSelect       = (decltype(g_pfnWSAEventSelect))     GetProcAddress(g_hModWinSock, "WSAEventSelect");
     g_pfnWSAEnumNetworkEvents = (decltype(g_pfnWSAEnumNetworkEvents))GetProcAddress(g_hModWinSock,"WSAEnumNetworkEvents");
@@ -392 +395 @@
     Assert(g_pfnWSACreateEvent       || g_fOldWinSock);
     Assert(g_pfnWSACloseEvent        || g_fOldWinSock);
+    Assert(g_pfnWSASetEvent          || g_fOldWinSock);
     Assert(g_pfnWSAEventSelect       || g_fOldWinSock);
     Assert(g_pfnWSAEnumNetworkEvents || g_fOldWinSock);

trunk/src/VBox/Runtime/r3/win/internal-r3-win.h

@@ -125 +125 @@
 /** WSACreateEvent */
 typedef HANDLE          (WINAPI *PFNWSACREATEEVENT)(void);
+/** WSASetEvent */
+typedef BOOL            (WINAPI *PFNWSASETEVENT)(HANDLE);
 /** WSACloseEvent */
 typedef BOOL            (WINAPI *PFNWSACLOSEEVENT)(HANDLE);
@@ -179 +181 @@
 extern DECLHIDDEN(PFNWSACREATEEVENT)               g_pfnWSACreateEvent;
 extern DECLHIDDEN(PFNWSACLOSEEVENT)                g_pfnWSACloseEvent;
+extern DECLHIDDEN(PFNWSASETEVENT)                  g_pfnWSASetEvent;
 extern DECLHIDDEN(PFNWSAEVENTSELECT)               g_pfnWSAEventSelect;
 extern DECLHIDDEN(PFNWSAENUMNETWORKEVENTS)         g_pfnWSAEnumNetworkEvents;