evdev: Extend EVIOCGRAB ioctl scope to cover sysmouse interface

of psm(4), ums(4) and sysmouse(4) drivers.
EVIOCGRAB ioctl execution on /dev/input/event# device node gains
exclusive access to this device to caller. It is used mostly for
development purposes and remote control software. See e.g.
https://reviews.freebsd.org/D30020 which is the reason of creation
of this change.

MFC after:	2 weeks
Tested by:	corvink
Differential revision:	https://reviews.freebsd.org/D30542

sys/dev/atkbdc/psm.c

@@ -5111,6 +5111,10 @@ psmsoftintr(void *arg)
 			break;
 		}
 
+	/* Store last packet for reinjection if it has not been set already */
+	if (timevalisset(&sc->idletimeout) && sc->idlepacket.inputbytes == 0)
+		sc->idlepacket = *pb;
+
 #ifdef EVDEV_SUPPORT
 	if (evdev_rcpt_mask & EVDEV_RCPT_HW_MOUSE &&
 	    sc->hw.model != MOUSE_MODEL_ELANTECH &&
@@ -5144,6 +5148,10 @@ psmsoftintr(void *arg)
 		evdev_push_mouse_btn(sc->evdev_r, ms.button);
 		evdev_sync(sc->evdev_r);
 	}
+
+	if ((sc->evdev_a != NULL && evdev_is_grabbed(sc->evdev_a)) ||
+	    (sc->evdev_r != NULL && evdev_is_grabbed(sc->evdev_r)))
+		goto next;
 #endif
 
 	/* scale values */
@@ -5164,10 +5172,6 @@ psmsoftintr(void *arg)
 		}
 	}
 
-	/* Store last packet for reinjection if it has not been set already */
-	if (timevalisset(&sc->idletimeout) && sc->idlepacket.inputbytes == 0)
-		sc->idlepacket = *pb;
-
 	ms.dx = x;
 	ms.dy = y;
 	ms.dz = z;

sys/dev/evdev/evdev.c

@@ -1094,6 +1094,17 @@ evdev_release_client(struct evdev_dev *evdev, struct evdev_client *client)
 	return (0);
 }
 
+bool
+evdev_is_grabbed(struct evdev_dev *evdev)
+{
+	/*
+	 * The function is intended to be called from evdev-unrelated parts of
+	 * code like syscons-compatible parts of mouse and keyboard drivers.
+	 * That makes unlocked read-only access acceptable.
+	 */
+	return (evdev->ev_grabber != NULL);
+}
+
 static void
 evdev_repeat_callout(void *arg)
 {

sys/dev/evdev/evdev.h

@@ -154,6 +154,7 @@ void evdev_set_repeat_params(struct evdev_dev *, uint16_t, int);
 int evdev_set_report_size(struct evdev_dev *, size_t);
 void evdev_set_flag(struct evdev_dev *, uint16_t);
 void *evdev_get_softc(struct evdev_dev *);
+bool evdev_is_grabbed(struct evdev_dev *);
 
 /* Multitouch related functions: */
 int evdev_mt_id_to_slot(struct evdev_dev *, int32_t);

sys/dev/syscons/sysmouse.c

@@ -295,6 +295,8 @@ sysmouse_event(mouse_info_t *info)
 
 #ifdef EVDEV_SUPPORT
 	smdev_evdev_write(x, y, z, mouse_status.button);
+	if (evdev_is_grabbed(sysmouse_evdev))
+		goto done;
 #endif
 
 	if (!tty_opened(sysmouse_tty))

sys/dev/usb/input/ums.c

@@ -875,6 +875,10 @@ ums_put_queue(struct ums_softc *sc, int32_t dx, int32_t dy,
 {
 	uint8_t buf[8];
 
+#ifdef EVDEV_SUPPORT
+	if (evdev_is_grabbed(sc->sc_evdev))
+		return;
+#endif
 	if (1) {
 		if (dx > 254)
 			dx = 254;

sys/dev/vt/vt_sysmouse.c

@@ -249,6 +249,8 @@ sysmouse_process_event(mouse_info_t *mi)
 
 #ifdef EVDEV_SUPPORT
 	sysmouse_evdev_store(x, y, z, sysmouse_status.button);
+	if (evdev_is_grabbed(sysmouse_evdev))
+		goto done;
 #endif
 
 	/* The first five bytes are compatible with MouseSystems. */