XQuartz: Add locking to make mieq thread safe on OSX

(cherry picked from commit 7a8d2266861e74176b5310b83652a9c10a170494)

hw/xquartz/darwinEvents.c

@@ -115,7 +115,8 @@ void darwinEvents_lock(void) {
     }
 }
 
-static inline void darwinEvents_unlock(void) {
+void darwinEvents_unlock(void);
+void darwinEvents_unlock(void) {
     int err;
     if((err = pthread_mutex_unlock(&mieq_lock))) {
         ErrorF("%s:%s:%d: Failed to unlock mieq_lock: %d\n",

mi/mieq.c

@@ -36,6 +36,11 @@ in this Software without prior written authorization from The Open Group.
 #include <dix-config.h>
 #endif
 
+#ifdef XQUARTZ
+#include  <pthread.h>
+static pthread_mutex_t miEventQueueMutex = PTHREAD_MUTEX_INITIALIZER;
+#endif
+
 # include   <X11/X.h>
 # include   <X11/Xmd.h>
 # include   <X11/Xproto.h>
@@ -138,6 +143,9 @@ mieqEnqueue(DeviceIntPtr pDev, xEvent *e)
     int                    isMotion = 0;
     int                    evlen;
 
+#ifdef XQUARTZ
+    pthread_mutex_lock(&miEventQueueMutex);
+#endif
 
     /* avoid merging events from different devices */
     if (e->u.u.type == MotionNotify)
@@ -156,6 +164,10 @@ mieqEnqueue(DeviceIntPtr pDev, xEvent *e)
         lastkbp = (deviceKeyButtonPointer *) laste->events->event;
 
         if (laste->nevents > 6) {
+#ifdef XQUARTZ
+            pthread_mutex_unlock(&miEventQueueMutex);
+#endif
+            
             ErrorF("[mi] mieqEnqueue: more than six valuator events; dropping.\n");
             return;
         }
@@ -167,11 +179,17 @@ mieqEnqueue(DeviceIntPtr pDev, xEvent *e)
               lastkbp->type == ProximityOut) ||
             ((lastkbp->deviceid & DEVICE_BITS) !=
              (v->deviceid & DEVICE_BITS))) {
+#ifdef XQUARTZ
+            pthread_mutex_unlock(&miEventQueueMutex);
+#endif
             ErrorF("[mi] mieqEnequeue: out-of-order valuator event; dropping.\n");
             return;
         }
 
         memcpy((laste->events[laste->nevents++].event), e, sizeof(xEvent));
+#ifdef XQUARTZ
+        pthread_mutex_unlock(&miEventQueueMutex);
+#endif
         return;
     }
 
@@ -191,6 +209,9 @@ mieqEnqueue(DeviceIntPtr pDev, xEvent *e)
 		xorg_backtrace();
 		stuck = 1;
 	    }
+#ifdef XQUARTZ
+	    pthread_mutex_unlock(&miEventQueueMutex);
+#endif
 	    return;
         }
 	stuck = 0;
@@ -208,6 +229,9 @@ mieqEnqueue(DeviceIntPtr pDev, xEvent *e)
         if (!evt->event)
         {
             ErrorF("[mi] Running out of memory. Tossing event.\n");
+#ifdef XQUARTZ
+            pthread_mutex_unlock(&miEventQueueMutex);
+#endif
             return;
         }
     }
@@ -228,24 +252,39 @@ mieqEnqueue(DeviceIntPtr pDev, xEvent *e)
 
     miEventQueue.lastMotion = isMotion;
     miEventQueue.tail = (oldtail + 1) % QUEUE_SIZE;
+#ifdef XQUARTZ
+    pthread_mutex_unlock(&miEventQueueMutex);
+#endif
 }
 
 void
 mieqSwitchScreen(DeviceIntPtr pDev, ScreenPtr pScreen, Bool fromDIX)
 {
+#ifdef XQUARTZ
+    pthread_mutex_lock(&miEventQueueMutex);
+#endif
     EnqueueScreen(pDev) = pScreen;
     if (fromDIX)
 	DequeueScreen(pDev) = pScreen;
+#ifdef XQUARTZ
+    pthread_mutex_unlock(&miEventQueueMutex);
+#endif
 }
 
 void
 mieqSetHandler(int event, mieqHandler handler)
 {
+#ifdef XQUARTZ
+    pthread_mutex_lock(&miEventQueueMutex);
+#endif
     if (handler && miEventQueue.handlers[event])
         ErrorF("[mi] mieq: warning: overriding existing handler %p with %p for "
                "event %d\n", miEventQueue.handlers[event], handler, event);
 
     miEventQueue.handlers[event] = handler;
+#ifdef XQUARTZ
+    pthread_mutex_unlock(&miEventQueueMutex);
+#endif
 }
 
 /**
@@ -317,6 +356,10 @@ mieqProcessInputEvents(void)
     DeviceIntPtr dev = NULL,
                  master = NULL;
 
+#ifdef XQUARTZ
+    pthread_mutex_lock(&miEventQueueMutex);
+#endif
+    
     while (miEventQueue.head != miEventQueue.tail) {
         e = &miEventQueue.events[miEventQueue.head];
 
@@ -340,6 +383,10 @@ mieqProcessInputEvents(void)
 
         miEventQueue.head = (miEventQueue.head + 1) % QUEUE_SIZE;
 
+#ifdef XQUARTZ
+        pthread_mutex_unlock(&miEventQueueMutex);
+#endif
+        
         type    = event->u.u.type;
         master  = (!dev->isMaster && dev->u.master) ? dev->u.master : NULL;
 
@@ -389,6 +436,13 @@ mieqProcessInputEvents(void)
         /* Update the sprite now. Next event may be from different device. */
         if (type == DeviceMotionNotify && (master || dev->isMaster))
             miPointerUpdateSprite(dev);
+
+#ifdef XQUARTZ
+        pthread_mutex_lock(&miEventQueueMutex);
+#endif
     }
+#ifdef XQUARTZ
+    pthread_mutex_unlock(&miEventQueueMutex);
+#endif
 }
 

mi/mipointer.c

@@ -547,6 +547,12 @@ miPointerGetPosition(DeviceIntPtr pDev, int *x, int *y)
     *y = MIPOINTER(pDev)->y;
 }
 
+#ifdef XQUARTZ
+#include <pthread.h>
+void darwinEvents_lock(void);
+void darwinEvents_unlock(void);
+#endif
+
 void
 miPointerMove (DeviceIntPtr pDev, ScreenPtr pScreen, int x, int y)
 {
@@ -573,7 +579,13 @@ miPointerMove (DeviceIntPtr pDev, ScreenPtr pScreen, int x, int y)
     nevents = GetPointerEvents(events, pDev, MotionNotify, 0, POINTER_ABSOLUTE, 0, 2, valuators);
 
     OsBlockSignals();
+#ifdef XQUARTZ
+    darwinEvents_lock();
+#endif
     for (i = 0; i < nevents; i++)
         mieqEnqueue(pDev, events[i].event);
+#ifdef XQUARTZ
+    darwinEvents_unlock();
+#endif
     OsReleaseSignals();
 }