input-linux: initialize key state

Query input device keys, initialize state accordingly, so the correct
state is reflected in case any key is pressed at initialization time.
There is a high chance for this to actually happen for the 'enter' key
in case you start qemu with a terminal command (directly or virsh).

When finding any pressed keys the input grab is delayed until all keys
are lifted, to avoid confusing guest and host with appearently stuck
keys.

Reported-by: Muted Bytes <mutedbytes@gmail.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 1476277384-30365-1-git-send-email-kraxel@redhat.com
diff --git a/ui/input-linux.c b/ui/input-linux.c
index 0e230ce..f345317 100644
--- a/ui/input-linux.c
+++ b/ui/input-linux.c
@@ -347,7 +347,8 @@
 static void input_linux_complete(UserCreatable *uc, Error **errp)
 {
     InputLinux *il = INPUT_LINUX(uc);
-    uint8_t evtmap, relmap, absmap, keymap[KEY_CNT / 8];
+    uint8_t evtmap, relmap, absmap;
+    uint8_t keymap[KEY_CNT / 8], keystate[KEY_CNT / 8];
     unsigned int i;
     int rc, ver;
 
@@ -394,6 +395,7 @@
     if (evtmap & (1 << EV_KEY)) {
         memset(keymap, 0, sizeof(keymap));
         rc = ioctl(il->fd, EVIOCGBIT(EV_KEY, sizeof(keymap)), keymap);
+        rc = ioctl(il->fd, EVIOCGKEY(sizeof(keystate)), keystate);
         for (i = 0; i < KEY_CNT; i++) {
             if (keymap[i / 8] & (1 << (i % 8))) {
                 if (linux_is_button(i)) {
@@ -401,12 +403,21 @@
                 } else {
                     il->num_keys++;
                 }
+                if (keystate[i / 8] & (1 << (i % 8))) {
+                    il->keydown[i] = true;
+                    il->keycount++;
+                }
             }
         }
     }
 
     qemu_set_fd_handler(il->fd, input_linux_event, NULL, il);
-    input_linux_toggle_grab(il);
+    if (il->keycount) {
+        /* delay grab until all keys are released */
+        il->grab_request = true;
+    } else {
+        input_linux_toggle_grab(il);
+    }
     QTAILQ_INSERT_TAIL(&inputs, il, next);
     il->initialized = true;
     return;