Xi: exevents: extra asserts on NULL pointers

Even though shouldn't be practically hit, better have some asserts,
giving us an idea of the point of cause, instead of segfaulting,
just in case.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

Xi/exevents.c

@@ -491,6 +491,7 @@ DeepCopyKeyboardClasses(DeviceIntPtr from, DeviceIntPtr to)
             if (!k->xkb_sli)
                 continue;
             if (k->xkb_sli->flags & XkbSLI_IsDefault) {
+                assert(to->key);
                 k->xkb_sli->names = to->key->xkbInfo->desc->names->indicators;
                 k->xkb_sli->maps = to->key->xkbInfo->desc->indicators->maps;
             }
@@ -1044,6 +1045,7 @@ TouchClientWantsOwnershipEvents(ClientPtr client, DeviceIntPtr dev,
 {
     InputClients *iclient;
 
+    assert(wOtherInputMasks(win));
     nt_list_for_each_entry(iclient, wOtherInputMasks(win)->inputClients, next) {
         if (rClient(iclient) != client)
             continue;
@@ -1389,6 +1391,8 @@ RetrieveTouchDeliveryData(DeviceIntPtr dev, TouchPointInfoPtr ti,
             else
                 evtype = GetXI2Type(ev->any.type);
 
+            assert(iclients);
+            assert(wOtherInputMasks(*win));
             nt_list_for_each_entry(iclients,
                                    wOtherInputMasks(*win)->inputClients, next)
                 if (xi2mask_isset(iclients->xi2mask, dev, evtype))
@@ -1403,6 +1407,7 @@ RetrieveTouchDeliveryData(DeviceIntPtr dev, TouchPointInfoPtr ti,
             int xi_type = GetXIType(TouchGetPointerEventType(ev));
             Mask xi_filter = event_get_filter_from_type(dev, xi_type);
 
+            assert(wOtherInputMasks(*win));
             nt_list_for_each_entry(iclients,
                                    wOtherInputMasks(*win)->inputClients, next)
                 if (iclients->mask[dev->id] & xi_filter)
@@ -2292,6 +2297,7 @@ RetrieveGestureDeliveryData(DeviceIntPtr dev, InternalEvent *ev, GestureListener
            listener->type == GESTURE_LISTENER_REGULAR */
         evtype = GetXI2Type(ev->any.type);
 
+        assert(wOtherInputMasks(*win));
         nt_list_for_each_entry(iclients, wOtherInputMasks(*win)->inputClients, next)
             if (xi2mask_isset(iclients->xi2mask, dev, evtype))
                 break;
@@ -2681,6 +2687,7 @@ SelectForWindow(DeviceIntPtr dev, WindowPtr pWin, ClientPtr client,
                     return BadAccess;
             }
         }
+        assert(wOtherInputMasks(pWin));
         for (others = wOtherInputMasks(pWin)->inputClients; others;
              others = others->next) {
             if (SameClient(others, client)) {
@@ -3242,8 +3249,11 @@ DeviceEventSuppressForWindow(WindowPtr pWin, ClientPtr client, Mask mask,
         inputMasks->dontPropagateMask[maskndx] = mask;
     }
     RecalculateDeviceDeliverableEvents(pWin);
-    if (ShouldFreeInputMasks(pWin, FALSE))
+    if (ShouldFreeInputMasks(pWin, FALSE)) {
+        BUG_RETURN_VAL(!inputMasks, BadImplementation);
+        BUG_RETURN_VAL(!inputMasks->inputClients, BadImplementation);
         FreeResource(inputMasks->inputClients->resource, X11_RESTYPE_NONE);
+    }
     return Success;
 }
 
@@ -3337,6 +3347,7 @@ XISetEventMask(DeviceIntPtr dev, WindowPtr win, ClientPtr client,
     if (len && !others) {
         if (AddExtensionClient(win, client, 0, 0) != Success)
             return BadAlloc;
+        assert(wOtherInputMasks(win));
         others = wOtherInputMasks(win)->inputClients;
     }
 
@@ -3346,6 +3357,7 @@ XISetEventMask(DeviceIntPtr dev, WindowPtr win, ClientPtr client,
     }
 
     if (len) {
+        assert(others);
         xi2mask_set_one_mask(others->xi2mask, dev->id, mask, len);
     }
 

Xi/xibarriers.c

@@ -124,8 +124,10 @@ static void FreePointerBarrierClient(struct PointerBarrierClient *c)
 {
     struct PointerBarrierDevice *pbd = NULL, *tmp = NULL;
 
-    xorg_list_for_each_entry_safe(pbd, tmp, &c->per_device, entry) {
+    if (!xorg_list_is_empty(&c->per_device)) {
-        free(pbd);
+        xorg_list_for_each_entry_safe(pbd, tmp, &c->per_device, entry) {
+            free(pbd);
+        }
     }
     free(c);
 }
@@ -721,14 +723,14 @@ static void add_master_func(void *res, XID id, void *devid)
 {
     struct PointerBarrier *b;
     struct PointerBarrierClient *barrier;
-    struct PointerBarrierDevice *pbd;
     int *deviceid = devid;
 
     b = res;
     barrier = container_of(b, struct PointerBarrierClient, barrier);
 
-
+    struct PointerBarrierDevice *pbd = AllocBarrierDevice();
-    pbd = AllocBarrierDevice();
+    if (!pbd)
+        return;
     pbd->deviceid = *deviceid;
 
     input_lock();