From 85d340f9e8b23f199b0fea54731ce28e942d2c7c Mon Sep 17 00:00:00 2001
From: Jeremy Huddleston <jeremyhu@freedesktop.org>
Date: Fri, 12 Sep 2008 15:18:51 -0700
Subject: [PATCH] XQuartz: Added locking into mieq to protect X from eating
 itself (cherry picked from commit 4904e04ce6cc2d1ea4300711ef11655a48931bc5)

---
 mi/mieq.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/mi/mieq.c b/mi/mieq.c
index 7d19f499a..f49074eb7 100644
--- a/mi/mieq.c
+++ b/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
+
 # define NEED_EVENTS
 # include   <X11/X.h>
 # include   <X11/Xmd.h>
@@ -105,6 +110,9 @@ mieqInit(void)
 void
 mieqEnqueue(DeviceIntPtr pDev, xEvent *e)
 {
+#ifdef XQUARTZ
+    pthread_mutex_lock(&miEventQueueMutex);
+#endif
     unsigned int           oldtail = miEventQueue.tail, newtail;
     int                    isMotion = 0;
     deviceValuator         *v = (deviceValuator *) e;
@@ -123,6 +131,9 @@ mieqEnqueue(DeviceIntPtr pDev, xEvent *e)
     if (e->u.u.type == DeviceValuator) {
         if (laste->nevents > 6) {
             ErrorF("[mi] mieqEnqueue: more than six valuator events; dropping.\n");
+#ifdef XQUARTZ
+            pthread_mutex_unlock(&miEventQueueMutex);
+#endif
             return;
         }
         if (oldtail == miEventQueue.head ||
@@ -134,9 +145,15 @@ mieqEnqueue(DeviceIntPtr pDev, xEvent *e)
             ((lastkbp->deviceid & DEVICE_BITS) !=
              (v->deviceid & DEVICE_BITS))) {
             ErrorF("[mi] mieqEnequeue: out-of-order valuator event; dropping.\n");
+#ifdef XQUARTZ
+            pthread_mutex_unlock(&miEventQueueMutex);
+#endif
             return;
         }
         memcpy(&(laste->event[laste->nevents++]), e, sizeof(xEvent));
+#ifdef XQUARTZ
+        pthread_mutex_unlock(&miEventQueueMutex);
+#endif
         return;
     }
 
@@ -152,6 +169,9 @@ mieqEnqueue(DeviceIntPtr pDev, xEvent *e)
 	if (newtail == miEventQueue.head) {
             ErrorF("[mi] EQ overflowing. The server is probably stuck "
                    "in an infinite loop.\n");
+#ifdef XQUARTZ
+            pthread_mutex_unlock(&miEventQueueMutex);
+#endif
 	    return;
         }
 	miEventQueue.tail = newtail;
@@ -173,24 +193,39 @@ mieqEnqueue(DeviceIntPtr pDev, xEvent *e)
     miEventQueue.events[oldtail].pDev = pDev;
 
     miEventQueue.lastMotion = isMotion;
+#ifdef XQUARTZ
+    pthread_mutex_unlock(&miEventQueueMutex);
+#endif
 }
 
 void
 mieqSwitchScreen(ScreenPtr pScreen, Bool fromDIX)
 {
+#ifdef XQUARTZ
+    pthread_mutex_lock(&miEventQueueMutex);
+#endif
     miEventQueue.pEnqueueScreen = pScreen;
     if (fromDIX)
 	miEventQueue.pDequeueScreen = 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("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
 }
 
 /* Call this from ProcessInputEvents(). */
@@ -201,6 +236,10 @@ mieqProcessInputEvents(void)
     int x = 0, y = 0;
     DeviceIntPtr dev = NULL;
 
+#ifdef XQUARTZ
+    pthread_mutex_lock(&miEventQueueMutex);
+#endif
+
     while (miEventQueue.head != miEventQueue.tail) {
         if (screenIsSaved == SCREEN_SAVER_ON)
             dixSaveScreens (serverClient, SCREEN_SAVER_OFF, ScreenSaverReset);
@@ -221,7 +260,6 @@ mieqProcessInputEvents(void)
             miEventQueue.handlers[e->event->u.u.type](miEventQueue.pDequeueScreen->myNum,
                                                       e->event, dev,
                                                       e->nevents);
-            return;
         }
         else if (e->pScreen != miEventQueue.pDequeueScreen) {
             /* Assumption - screen switching can only occur on motion events. */
@@ -251,4 +289,7 @@ mieqProcessInputEvents(void)
             dev->public.processInputProc(e->event, dev, e->nevents);
         }
     }
+#ifdef XQUARTZ
+    pthread_mutex_unlock(&miEventQueueMutex);
+#endif
 }