Add implicitGrab field to GrabInfoRec.

Is set when passive grab is implicit as result of a ButtonPress event. If this
is the case, we need to store the XI mask as well as the core mask to ensure
delivery of XI events during the grab's lifetime.

Remove all core grabs on other devices when client issues a GrabPointer or
GrabKeyboard request. Let's assume that the client really only wants one
device to interact, so this seems like a reasonable solution.

dix/devices.c

@@ -135,6 +135,7 @@ AddInputDevice(DeviceProc deviceProc, Bool autoStart)
     dev->deviceGrab.grab = NullGrab;
     dev->deviceGrab.grabTime = currentTime;
     dev->deviceGrab.fromPassiveGrab = FALSE;
+    dev->deviceGrab.implicitGrab = FALSE;
 
     dev->key = (KeyClassPtr)NULL;
     dev->valuator = (ValuatorClassPtr)NULL;

dix/events.c

@@ -209,6 +209,12 @@ static xEvent *xeviexE;
 	ShiftMask | LockMask | ControlMask | Mod1Mask | Mod2Mask | \
 	Mod3Mask | Mod4Mask | Mod5Mask )
 #define AllEventMasks (lastEventMask|(lastEventMask-1))
+
+/**
+ * Used to indicate a implicit passive grab created by a ButtonPress event.
+ * See DeliverEventsToWindow().
+ */
+#define ImplicitGrabMask (1 << 7)
 /*
  * The following relies on the fact that the Button<n>MotionMasks are equal
  * to the corresponding Button<n>Masks from the current modifier/button state.
@@ -1238,6 +1244,14 @@ PlayReleasedEvents(void)
     } 
 }
 
+/**
+ * Freeze or thaw the given devices. The device's processing proc is
+ * switched to either the real processing proc (in case of thawing) or an
+ * enqueuing processing proc (usually EnqueueEvent()).
+ *
+ * @param dev The device to freeze/thaw
+ * @param frozen True to freeze or false to thaw.
+ */
 static void
 FreezeThaw(DeviceIntPtr dev, Bool frozen)
 {
@@ -1248,6 +1262,14 @@ FreezeThaw(DeviceIntPtr dev, Bool frozen)
 	dev->public.processInputProc = dev->public.realInputProc;
 }
 
+/**
+ * Unfreeze devices and replay all events to the respective clients.
+ *
+ * ComputeFreezes takes the first event in the device's frozen event queue. It
+ * runs up the sprite tree (spriteTrace) and searches for the window to replay
+ * the events from. If it is found, it checks for passive grabs one down from
+ * the window or delivers the events.
+ */
 void
 ComputeFreezes(void)
 {
@@ -1394,7 +1416,8 @@ CheckGrabForSyncs(DeviceIntPtr thisDev, Bool thisMode, Bool otherMode)
  * on, but core events will be sent to other clients.
  * Can cause the cursor to change if a grab cursor is set.
  * 
- * Extension devices are set up for ActivateKeyboardGrab().
+ * Note that parameter autoGrab may be (True & ImplicitGrabMask) if the grab
+ * is an implicit grab caused by a ButtonPress event.
  * 
  * @param mouse The device to grab.
  * @param grab The grab structure, needs to be setup.
@@ -1428,7 +1451,8 @@ ActivatePointerGrab(DeviceIntPtr mouse, GrabPtr grab,
 	grab->cursor->refcnt++;
     grabinfo->activeGrab = *grab;
     grabinfo->grab = &grabinfo->activeGrab;
-    grabinfo->fromPassiveGrab = autoGrab;
+    grabinfo->fromPassiveGrab = autoGrab & ~ImplicitGrabMask;
+    grabinfo->implicitGrab = autoGrab & ImplicitGrabMask;
     PostNewCursor(mouse);
     CheckGrabForSyncs(mouse,(Bool)grab->pointerMode, (Bool)grab->keyboardMode);
 }
@@ -1987,7 +2011,8 @@ DeliverEventsToWindow(DeviceIntPtr pDev, WindowPtr pWin, xEvent
 
         tempGrab.genericMasks = NULL;
 	(*inputInfo.pointer->deviceGrab.ActivateGrab)(pDev, &tempGrab,
-					   currentTime, TRUE);
+					   currentTime, 
+                                           TRUE | ImplicitGrabMask);
     }
     else if ((type == MotionNotify) && deliveries)
 	pDev->valuator->motionHintWindow = pWin;
@@ -3243,13 +3268,19 @@ DeliverGrabbedEvent(xEvent *xE, DeviceIntPtr thisDev,
             } else 
             {
                 Mask mask = grab->eventMask;
-                if (grabinfo->fromPassiveGrab && (xE->u.u.type &
-                            EXTENSION_EVENT_BASE))
+                if (grabinfo->fromPassiveGrab  &&
+                        grabinfo->implicitGrab && 
+                        (xE->u.u.type & EXTENSION_EVENT_BASE))
                     mask = grab->deviceMask;
 
                 FixUpEventFromWindow(thisDev, xE, grab->window, None, TRUE);
-                deliveries = TryClientEvents(rClient(grab), xE, count,
-                        mask, filters[xE->u.u.type], grab);
+
+                if (!(!(xE->u.u.type & EXTENSION_EVENT_BASE) &&
+                        IsInterferingGrab(rClient(grab), thisDev, xE)))
+                {
+                    deliveries = TryClientEvents(rClient(grab), xE, count,
+                            mask, filters[xE->u.u.type], grab);
+                }
             }
             if (deliveries && (xE->u.u.type == MotionNotify
 #ifdef XINPUT
@@ -4629,6 +4660,8 @@ ProcGrabPointer(ClientPtr client)
 	if (oldCursor)
 	    FreeCursor (oldCursor, (Cursor)0);
 	rep.status = GrabSuccess;
+
+        RemoveOtherCoreGrabs(client, device);
     }
     WriteReplyToClient(client, sizeof(xGrabPointerReply), &rep);
     return Success;
@@ -4797,6 +4830,47 @@ GrabDevice(ClientPtr client, DeviceIntPtr dev,
     return Success;
 }
 
+/**
+ * Deactivate any core grabs on the given client except the given device.
+ *
+ * This fixes race conditions where clients deal with implicit passive grabs
+ * on one device, but then actively grab their client pointer, which is
+ * another device.
+ *
+ * Grabs are only removed if the other device matches the type of device. If
+ * dev is a pointer device, only other pointer grabs are removed. Likewise, if
+ * dev is a keyboard device, only keyboard grabs are removed.
+ * 
+ * If dev doesn't have a grab, do nothing and go for a beer.
+ *
+ * @param client The client that is to be limited.
+ * @param dev The only device allowed to have a grab on the client.
+ */
+
+_X_EXPORT void
+RemoveOtherCoreGrabs(ClientPtr client, DeviceIntPtr dev)
+{
+    if (!dev || !dev->deviceGrab.grab)
+        return;
+
+    DeviceIntPtr it = inputInfo.devices;
+    for (; it; it = it->next)
+    {
+        if (it == dev)
+            continue;
+        /* check for IsPointer Device */
+
+        if (it->deviceGrab.grab &&
+                it->deviceGrab.grab->coreGrab &&
+                SameClient(it->deviceGrab.grab, client))
+        {
+            if ((IsPointerDevice(dev) && IsPointerDevice(it)) ||
+                    (IsKeyboardDevice(dev) && IsKeyboardDevice(it)))
+                (*it->deviceGrab.DeactivateGrab)(it);
+        }
+    }
+}
+
 /**
  * Server-side protocol handling for GrabKeyboard request.
  *
@@ -4813,10 +4887,13 @@ ProcGrabKeyboard(ClientPtr client)
     REQUEST_SIZE_MATCH(xGrabKeyboardReq);
 
     if (XaceHook(XACE_DEVICE_ACCESS, client, keyboard, TRUE))
+    {
 	result = GrabDevice(client, keyboard, stuff->keyboardMode,
 			    stuff->pointerMode, stuff->grabWindow,
 			    stuff->ownerEvents, stuff->time,
 			    KeyPressMask | KeyReleaseMask, &rep.status, TRUE);
+        RemoveOtherCoreGrabs(client, keyboard);
+    }
     else {
 	result = Success;
 	rep.status = AlreadyGrabbed;
@@ -5857,3 +5934,4 @@ ExtUngrabDevice(ClientPtr client, DeviceIntPtr dev)
 }
 
 
+

include/dix.h

@@ -494,6 +494,10 @@ extern int GrabDevice(
     CARD8 * /* status */,
     Bool /* coreGrab */);
 
+extern void RemoveOtherCoreGrabs(
+    ClientPtr /* client */,
+    DeviceIntPtr /* dev */);
+
 extern void InitEvents(void);
 extern void InitSprite(
         DeviceIntPtr /* pDev */, 

include/inputstr.h

@@ -333,9 +333,11 @@ typedef struct {
 #define FROZEN_NO_EVENT		5
 #define FROZEN_WITH_EVENT	6
 #define THAW_OTHERS		7
+
 typedef struct _GrabInfoRec {
-    TimeStamp	    grabTime;
-    Bool            fromPassiveGrab;
+    TimeStamp	    grabTime;           
+    Bool            fromPassiveGrab;    /* true if from passive grab */
+    Bool            implicitGrab;       /* implicit from ButtonPress */
     GrabRec         activeGrab;
     GrabPtr         grab;
     CARD8           activatingKey;