libNX_X11: add additional checks for dpy and xkb

We have seen crashes during session shutdown/connection problems here. These patches should avoid them. There's no proper way to test them, but they should do no harm.. Fixes ArcticaProject/nx-libs#801 Fixes https://bugs.x2go.org/cgi-bin/bugreport.cgi?bug=695

libNX_X11: add additional checks for dpy and xkb
20353e96 · Ulrich Sibiller · 4df77fe7 · 20353e96
Commit 20353e96 authored May 15, 2019 by Ulrich Sibiller
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XKBBind.c nx-X11/lib/src/xkb/XKBBind.c +14 -0

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--- a/nx-X11/lib/src/xkb/XKBBind.c
+++ b/nx-X11/lib/src/xkb/XKBBind.c
@@ -108,7 +108,21 @@ XKeycodeToKeysym(Display *dpy,
    _XkbCheckPendingRefresh(dpy, dpy->xkb_info);
+#ifdef NX_TRANS_SOCKET
+    /*
+       check again, we have seen cases where the connection broke
+       during CheckPendingEvents(), followed by a crash when accessing
+       dpy. See https://github.com/ArcticaProject/nx-libs/issues/801
+    */
+    if (_XkbUnavailable(dpy))
+        return _XKeycodeToKeysym(dpy, kc, col);
+#endif
    xkb = dpy->xkb_info->desc;
+#ifdef NX_TRANS_SOCKET
+    if (xkb == NULL)
+        return _XKeycodeToKeysym(dpy, kc, col);
+#endif
    if ((kc < xkb->min_key_code) || (kc > xkb->max_key_code))
        return NoSymbol;