input: Handle correctly failure to compile XKB keymaps

And ultimately, fail to start when there are no input devices on the
system. Patchs adds consistency to touch/pointer initialization to
return -1 in case same thing happens.

Further more, when the device is not created we can't assume to retrieve
a valid one from a libinput_device so guard against it. This takes care of
hot-plugging situations when we couldn't create the (keyboard) device,
or when removing it.

Fixes: #117, #402, #485

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Suggested-by: Daniel Stone <daniel.stone@collabora.com>

libweston/input.c

@@ -3331,7 +3331,7 @@ weston_seat_release_keyboard(struct weston_seat *seat)
 	}
 }
 
-WL_EXPORT void
+WL_EXPORT int
 weston_seat_init_pointer(struct weston_seat *seat)
 {
 	struct weston_pointer *pointer;
@@ -3340,18 +3340,20 @@ weston_seat_init_pointer(struct weston_seat *seat)
 		seat->pointer_device_count += 1;
 		if (seat->pointer_device_count == 1)
 			seat_send_updated_caps(seat);
-		return;
+		return 0;
 	}
 
 	pointer = weston_pointer_create(seat);
 	if (pointer == NULL)
-		return;
+		return -1;
 
 	seat->pointer_state = pointer;
 	seat->pointer_device_count = 1;
 	pointer->seat = seat;
 
 	seat_send_updated_caps(seat);
+
+	return 0;
 }
 
 WL_EXPORT void
@@ -3377,7 +3379,7 @@ weston_seat_release_pointer(struct weston_seat *seat)
 	}
 }
 
-WL_EXPORT void
+WL_EXPORT int
 weston_seat_init_touch(struct weston_seat *seat)
 {
 	struct weston_touch *touch;
@@ -3386,18 +3388,20 @@ weston_seat_init_touch(struct weston_seat *seat)
 		seat->touch_device_count += 1;
 		if (seat->touch_device_count == 1)
 			seat_send_updated_caps(seat);
-		return;
+		return 0;
 	}
 
 	touch = weston_touch_create();
 	if (touch == NULL)
-		return;
+		return -1;
 
 	seat->touch_state = touch;
 	seat->touch_device_count = 1;
 	touch->seat = seat;
 
 	seat_send_updated_caps(seat);
+
+	return 0;
 }
 
 WL_EXPORT void

libweston/libinput-device.c

@@ -523,6 +523,9 @@ evdev_device_process_event(struct libinput_event *event)
 	int handled = 1;
 	bool need_frame = false;
 
+	if (!device)
+		return 0;
+
 	switch (libinput_event_get_type(event)) {
 	case LIBINPUT_EVENT_KEYBOARD_KEY:
 		handle_keyboard_key(libinput_device,
@@ -728,13 +731,27 @@ evdev_device_create(struct libinput_device *libinput_device,
 
 	if (libinput_device_has_capability(libinput_device,
 					   LIBINPUT_DEVICE_CAP_KEYBOARD)) {
-		weston_seat_init_keyboard(seat, NULL);
+		if (weston_seat_init_keyboard(seat, NULL) < 0) {
+			free(device);
+			return NULL;
+		}
+
 		device->seat_caps |= EVDEV_SEAT_KEYBOARD;
 	}
 
 	if (libinput_device_has_capability(libinput_device,
 					   LIBINPUT_DEVICE_CAP_TOUCH)) {
-		weston_seat_init_touch(seat);
+		if (weston_seat_init_touch(seat) < 0) {
+			/* maybe we're a keyboard + touch device thus we need
+			 * to release the keyboard in case we couldn't make use
+			 * of the touch */
+			if (device->seat_caps & EVDEV_SEAT_KEYBOARD)
+				weston_seat_release_keyboard(seat);
+
+			free(device);
+			return NULL;
+		}
+
 		device->seat_caps |= EVDEV_SEAT_TOUCH;
 		device->touch_device = create_touch_device(device);
 	}

libweston/libinput-seat.c

@@ -150,6 +150,9 @@ device_removed(struct udev_input *input, struct libinput_device *libinput_device
 	struct evdev_device *device;
 
 	device = libinput_device_get_user_data(libinput_device);
+	if (!device)
+		return;
+
 	evdev_device_destroy(device);
 }
 

libweston/libweston-internal.h

@@ -188,13 +188,13 @@ weston_seat_release(struct weston_seat *seat);
 void
 weston_seat_send_selection(struct weston_seat *seat, struct wl_client *client);
 
-void
+int
 weston_seat_init_pointer(struct weston_seat *seat);
 
 int
 weston_seat_init_keyboard(struct weston_seat *seat, struct xkb_keymap *keymap);
 
-void
+int
 weston_seat_init_touch(struct weston_seat *seat);
 
 void