[Spice-devel] [spice-gtk v2] widget: Do not ignore unsupported keys from keyboard

[Frediano Ziglio]

If Windows layout does not support a given key the resulting virtual code
is set to 0xFF. To avoid losing this raw key (causing the key not been
sent to remote machine) detect this condition and handle the key.
The check for raw scancode is there to understand if we can handle
correctly the key in following code.
This problem can happen for instance using a 106 key Japanese keyboard
while the layout is set in English; in this case keys like CONVERT not
forwarded correctly.

Some note on how to reproduce and test this problem.

Physical way:
1- get a 106 key Japanese keyboard for your Windows client machine;
2- setup your client to English keyboard layout;
3- connect to a Linux machine (no matter the distro or version or
   keyboard configuration);
4- open "xinput test-xi2 <device>" command on Linux (device is
   the "AT" device in this case);
5- press CONVERT or other keys not present on an English keyboard.

Virtual way (Windows machine on a VM):
- set machine remote to VNC;
- assure Qmeu has lock-key-sync=off option to vnc;
- connect to Windows machine with a VNC client (I suggest TigerVNC
  as remote-viewer do some keyboard insertion);
- do steps 2, 3, 4 above
- press the CONVERT key. If you don't have you can simulate, either
  - change VNC client code to insert scancode 0x70 instead of another
    key and press this key;
  - disconnect main VNC client and use some tool to inject keys
    (I use a modifier version of vncdotool).

Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
---
 src/spice-widget.c | 38 ++++++++++++++++++++------------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/src/spice-widget.c b/src/spice-widget.c
index 51a2055..b5936bc 100644
--- a/src/spice-widget.c
+++ b/src/spice-widget.c
@@ -1406,7 +1406,7 @@ static gboolean key_event(GtkWidget *widget, GdkEventKey *key)
 {
     SpiceDisplay *display = SPICE_DISPLAY(widget);
     SpiceDisplayPrivate *d = display->priv;
-    int scancode;
+    int scancode = 0;
 #ifdef G_OS_WIN32
     int native_scancode;
     WORD langid = LOWORD(GetKeyboardLayout(0));
@@ -1414,8 +1414,23 @@ static gboolean key_event(GtkWidget *widget, GdkEventKey *key)
 #endif
 
 #ifdef G_OS_WIN32
+    /* Try to get scancode with gdk_event_get_scancode.
+     * This API is available from 3.22 or if backported.
+     */
+#if HAVE_GDK_EVENT_GET_SCANCODE
+    native_scancode = gdk_event_get_scancode((GdkEvent *) key);
+    if (native_scancode) {
+        scancode = native_scancode & 0x1ff;
+        /* Windows always set extended attribute for these keys */
+        if (scancode == (0x100|DIK_NUMLOCK) || scancode == (0x100|DIK_RSHIFT))
+            scancode &= 0xff;
+    }
+#else
+    native_scancode = 0;
+#endif
+
     /* on windows, we ought to ignore the reserved key event? */
-    if (key->hardware_keycode == 0xff)
+    if (!native_scancode && key->hardware_keycode == 0xff)
         return false;
 
     if (!d->keyboard_grab_active) {
@@ -1455,23 +1470,10 @@ static gboolean key_event(GtkWidget *widget, GdkEventKey *key)
     if (!d->inputs)
         return true;
 
-    scancode = vnc_display_keymap_gdk2xtkbd(d->keycode_map, d->keycode_maplen,
-                                            key->hardware_keycode);
+    if (!scancode)
+        scancode = vnc_display_keymap_gdk2xtkbd(d->keycode_map, d->keycode_maplen,
+                                                key->hardware_keycode);
 #ifdef G_OS_WIN32
-    /* Try to get scancode with gdk_event_get_scancode.
-     * This API is available from 3.22 or if backported.
-     */
-#if HAVE_GDK_EVENT_GET_SCANCODE
-    native_scancode = gdk_event_get_scancode((GdkEvent *) key);
-    if (native_scancode) {
-        scancode = native_scancode & 0x1ff;
-        /* Windows always set extended attribute for these keys */
-        if (scancode == (0x100|DIK_NUMLOCK) || scancode == (0x100|DIK_RSHIFT))
-            scancode &= 0xff;
-    }
-#else
-    native_scancode = 0;
-#endif
     if (!native_scancode) {
         native_scancode = MapVirtualKey(key->hardware_keycode, MAPVK_VK_TO_VSC);
         /* MapVirtualKey doesn't return scancode with needed higher byte */
-- 
2.7.4