Store TS_SYNC_EVENT before module load

When a connection is made to a system with the client numlock pressed, a
TS_SYNC_EVENT is sent before the module is loaded. This TS_SYNC_EVENT
correctly contains the NumLock status as 'pressed'. The event is, however,
discarded as the module isn't loaded.

When the module is loaded, a TS_SYNC_EVENT is not sent again unless
client focus is removed from the xrdp window and re-applied. As a
result, the NumLock state is incorrect unless this is done.

This commit stores the last TS_SYNC_EVENT sent before a module is
loaded. When the module is loaded, the sync state can be correctly
communicated to the module.

xrdp/xrdp_mm.c

@@ -526,6 +526,18 @@ xrdp_mm_setup_mod2(struct xrdp_mm *self)
         if (self->mod->mod_connect(self->mod) == 0)
         {
             rv = 0; /* connect success */
+
+            // If we've received a recent TS_SYNC_EVENT, pass it on to
+            // the module so (e.g.) NumLock starts in the right state.
+            if (self->last_sync_saved)
+            {
+                int key_flags = self->last_sync_key_flags;
+                int device_flags = self->last_sync_device_flags;
+                self->last_sync_saved = 0;
+                self->mod->mod_event(self->mod, WM_KEYBRD_SYNC, key_flags,
+                                     device_flags, key_flags, device_flags);
+
+            }
         }
         else
         {

xrdp/xrdp_types.h

@@ -447,6 +447,10 @@ struct xrdp_mm
     struct display_control_monitor_layout_data *resize_data;
     struct list *resize_queue;
     tbus resize_ready;
+    /* Last sync event if a module isn't loaded */
+    int last_sync_saved;
+    int last_sync_key_flags;
+    int last_sync_device_flags;
 };
 
 struct xrdp_key_info

xrdp/xrdp_wm.c

@@ -1673,13 +1673,18 @@ xrdp_wm_key_sync(struct xrdp_wm *self, int device_flags, int key_flags)
         self->caps_lock = 1;
     }
 
-    if (self->mm->mod != 0)
+    if (self->mm->mod != 0 && self->mm->mod->mod_event != 0)
     {
-        if (self->mm->mod->mod_event != 0)
-        {
-            self->mm->mod->mod_event(self->mm->mod, WM_KEYBRD_SYNC, key_flags,
-                                     device_flags, key_flags, device_flags);
-        }
+        self->mm->mod->mod_event(self->mm->mod, WM_KEYBRD_SYNC, key_flags,
+                                 device_flags, key_flags, device_flags);
+    }
+    else
+    {
+        // Save the event for when the module is loaded
+        self->mm->last_sync_saved = 1;
+        self->mm->last_sync_key_flags = key_flags;
+        self->mm->last_sync_device_flags = device_flags;
+
     }
 
     return 0;