From a48e2d8532a6116d82e3e6c0eec50113c50e7774 Mon Sep 17 00:00:00 2001
From: "Enrico Weigelt, metux IT consult" <info@metux.net>
Date: Wed, 7 May 2025 14:19:45 +0200
Subject: [PATCH] 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 | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Xi/exevents.c b/Xi/exevents.c
index e28b60210..dd0e6e1f7 100644
--- a/Xi/exevents.c
+++ b/Xi/exevents.c
@@ -490,6 +490,7 @@ 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;
             }
@@ -1043,6 +1044,7 @@ 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;
@@ -1388,6 +1390,8 @@ 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))
@@ -1402,6 +1406,7 @@ 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)
@@ -2291,6 +2296,7 @@ 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;
@@ -2680,6 +2686,7 @@ 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)) {
@@ -3339,6 +3346,7 @@ 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;
     }
 
@@ -3348,6 +3356,7 @@ XISetEventMask(DeviceIntPtr dev, WindowPtr win, ClientPtr client,
     }
 
     if (len) {
+        assert(others);
         xi2mask_set_one_mask(others->xi2mask, dev->id, mask, len);
     }