kbd keds: vnc

Use led status notification support in vnc.

The qemu vnc server keeps track of the capslock and numlock states based
on the key presses it receives from the vnc client.  But this fails in
case the guests idea of the capslock and numlock state changes for other
reasons.  One case is guest reboot (+ keyboard reset).  Another case are
more recent windows versions which reset capslock state before
presenting the login screen.

Usually guests use the keyboard leds to signal the capslock and numlock
state to the user, so we can use this to better keep track of capslock
and numlock state in the qemu vnc server.

Also toggle the numlock and capslock states on keydown events (instead
of keyup).  Guests do the same.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

vnc.c

@@ -1111,6 +1111,7 @@ static void vnc_disconnect_finish(VncState *vs)
     }
 
     vnc_remove_timer(vs->vd);
+    qemu_remove_led_event_handler(vs->led);
     qemu_free(vs);
 }
 
@@ -1501,6 +1502,22 @@ static void press_key(VncState *vs, int keysym)
     kbd_put_keycode(keycode | SCANCODE_UP);
 }
 
+static void kbd_leds(void *opaque, int ledstate)
+{
+    VncState *vs = opaque;
+    int caps, num;
+
+    caps = ledstate & QEMU_CAPS_LOCK_LED ? 1 : 0;
+    num  = ledstate & QEMU_NUM_LOCK_LED  ? 1 : 0;
+
+    if (vs->modifiers_state[0x3a] != caps) {
+        vs->modifiers_state[0x3a] = caps;
+    }
+    if (vs->modifiers_state[0x45] != num) {
+        vs->modifiers_state[0x45] = num;
+    }
+}
+
 static void do_key_event(VncState *vs, int down, int keycode, int sym)
 {
     /* QEMU console switch */
@@ -1526,7 +1543,7 @@ static void do_key_event(VncState *vs, int down, int keycode, int sym)
         break;
     case 0x3a:                        /* CapsLock */
     case 0x45:                        /* NumLock */
-        if (!down)
+        if (down)
             vs->modifiers_state[keycode] ^= 1;
         break;
     }
@@ -2412,6 +2429,7 @@ static void vnc_connect(VncDisplay *vd, int csock)
     vnc_flush(vs);
     vnc_read_when(vs, protocol_version, 12);
     reset_keys(vs);
+    vs->led = qemu_add_led_event_handler(kbd_leds, vs);
 
     vnc_init_timer(vd);
 

vnc.h

@@ -161,6 +161,7 @@ struct VncState
     size_t read_handler_expect;
     /* input */
     uint8_t modifiers_state[256];
+    QEMUPutLEDEntry *led;
 
     Buffer zlib;
     Buffer zlib_tmp;