backend/libinput/backend.c, backend/libinput/tablet_pad.c, backend/libinput/tablet_tool.c, backend/session/session.c: make udev optional

backend/libinput/backend.c

@@ -5,10 +5,16 @@
 #include <wlr/backend/interface.h>
 #include <wlr/backend/session.h>
 #include <wlr/util/log.h>
+#include <wlr/config.h>
 #include "backend/libinput.h"
-#include "backend/session/dev_udev.h"
 #include "util/signal.h"
 
+#if WLR_HAS_UDEV
+#include "backend/session/dev_udev.h"
+#endif
+
+#define NETLINK_BITMASK 4
+
 static struct wlr_libinput_backend *get_libinput_backend_from_backend(
 		struct wlr_backend *wlr_backend) {
 	assert(wlr_backend_is_libinput(wlr_backend));
@@ -87,15 +93,29 @@ static bool backend_start(struct wlr_backend *wlr_backend) {
 		get_libinput_backend_from_backend(wlr_backend);
 	wlr_log(WLR_DEBUG, "Starting libinput backend");
 
+#if WLR_HAS_UDEV
 	backend->libinput_context = libinput_udev_create_context(&libinput_impl,
 		backend, backend->session->dev->udev);
+#elif defined(__linux__)
+	backend->libinput_context = libinput_netlink_create_context(&libinput_impl,
+		backend, NETLINK_BITMASK);
+#else
+#error Unsupported platform
+#endif
 	if (!backend->libinput_context) {
 		wlr_log(WLR_ERROR, "Failed to create libinput context");
 		return false;
 	}
 
+#if WLR_HAS_UDEV
 	if (libinput_udev_assign_seat(backend->libinput_context,
 			backend->session->seat) != 0) {
+#elif defined(__linux__)
+	if (libinput_netlink_assign_seat(backend->libinput_context,
+			backend->session->seat) != 0) {
+#else
+#error Unsupported platform
+#endif
 		wlr_log(WLR_ERROR, "Failed to assign libinput seat");
 		return false;
 	}

backend/libinput/tablet_pad.c

@@ -3,12 +3,16 @@
 #include <string.h>
 #include <libinput.h>
 #include <stdlib.h>
-#include <libudev.h>
 #include <wlr/interfaces/wlr_tablet_pad.h>
 #include <wlr/util/log.h>
+#include <wlr/config.h>
 #include "backend/libinput.h"
 #include "util/signal.h"
 
+#if WLR_HAS_UDEV
+#include <libudev.h>
+#endif
+
 const struct wlr_tablet_pad_impl libinput_tablet_pad_impl = {
 	.name = "libinput-tablet-pad",
 };
@@ -107,9 +111,11 @@ void init_device_tablet_pad(struct wlr_libinput_input_device *dev) {
 	wlr_tablet_pad->strip_count =
 		libinput_device_tablet_pad_get_num_strips(handle);
 
+#if WLR_HAS_UDEV
 	struct udev_device *udev = libinput_device_get_udev_device(handle);
 	char **dst = wl_array_add(&wlr_tablet_pad->paths, sizeof(char *));
 	*dst = strdup(udev_device_get_syspath(udev));
+#endif
 
 	int groups = libinput_device_tablet_pad_get_num_mode_groups(handle);
 	for (int i = 0; i < groups; ++i) {

backend/libinput/tablet_tool.c

@@ -3,12 +3,16 @@
 #include <assert.h>
 #include <libinput.h>
 #include <stdlib.h>
-#include <libudev.h>
 #include <wlr/interfaces/wlr_tablet_tool.h>
 #include <wlr/util/log.h>
+#include <wlr/config.h>
 #include "backend/libinput.h"
 #include "util/signal.h"
 
+#if WLR_HAS_UDEV
+#include <libudev.h>
+#endif
+
 struct tablet_tool {
 	struct wlr_tablet_tool wlr_tool;
 	struct libinput_tablet_tool *handle;
@@ -29,9 +33,11 @@ void init_device_tablet(struct wlr_libinput_input_device *dev) {
 	libinput_device_get_size(dev->handle, &wlr_tablet->width_mm,
 		&wlr_tablet->height_mm);
 
+#if WLR_HAS_UDEV
 	struct udev_device *udev = libinput_device_get_udev_device(dev->handle);
 	char **dst = wl_array_add(&wlr_tablet->paths, sizeof(char *));
 	*dst = strdup(udev_device_get_syspath(udev));
+#endif
 
 	wl_list_init(&dev->tablet_tools);
 }

backend/session/meson.build

@@ -3,5 +3,20 @@ libseat = dependency('libseat',
 	fallback: 'seatd',
 	default_options: ['server=disabled', 'man-pages=disabled'],
 )
-wlr_files += files('session.c', 'dev_udev.c')
+wlr_files += files('session.c')
 wlr_deps += libseat
+
+# libudev
+
+if get_option('enum-backend') == 'auto'
+	udev = dependency('libudev', required: false)
+	if udev.found()
+		wlr_files += files('dev_udev.c')
+		wlr_deps += udev
+		features += { 'udev': true }
+	endif
+elif get_option('enum-backend') == 'udev'
+	wlr_files += files('dev_udev.c')
+	wlr_deps += dependency('libudev')
+	features += { 'udev': true }
+endif

backend/session/session.c

@@ -144,10 +144,12 @@ struct wlr_session *wlr_session_create(struct wl_display *disp) {
 		goto error_open;
 	}
 
+#if WLR_HAS_UDEV
 	if (dev_init(session, disp) == -1) {
 		wlr_log(WLR_ERROR, "Failed to initialize dev backend");
 		goto error_session;
 	}
+#endif
 
 	session->display = disp;
 
@@ -156,8 +158,10 @@ struct wlr_session *wlr_session_create(struct wl_display *disp) {
 
 	return session;
 
+#if WLR_HAS_UDEV
 error_session:
 	libseat_session_finish(session);
+#endif
 error_open:
 	free(session);
 	return NULL;
@@ -171,7 +175,9 @@ void wlr_session_destroy(struct wlr_session *session) {
 	wlr_signal_emit_safe(&session->events.destroy, session);
 	wl_list_remove(&session->display_destroy.link);
 
+#if WLR_HAS_UDEV
 	dev_finish(session);
+#endif
 
 	struct wlr_device *dev, *tmp_dev;
 	wl_list_for_each_safe(dev, tmp_dev, &session->devices, link) {
@@ -293,5 +299,9 @@ ssize_t wlr_session_find_gpus(struct wlr_session *session,
 		return explicit_find_gpus(session, ret_len, ret, explicit);
 	}
 
+#if WLR_HAS_UDEV
 	return dev_find_gpus(session, ret_len, ret);
+#endif
+
+	return -1;
 }

include/wlr/config.h.in

@@ -11,4 +11,6 @@
 
 #mesondefine WLR_HAS_XWAYLAND
 
+#mesondefine WLR_HAS_UDEV
+
 #endif

meson.build

@@ -92,6 +92,7 @@ features = {
 	'xwayland': false,
 	'gles2-renderer': false,
 	'vulkan-renderer': false,
+	'udev': false,
 }
 internal_features = {
 	'xcb-errors': false,
@@ -127,7 +128,6 @@ drm = dependency('libdrm',
 )
 gbm = dependency('gbm', version: '>=17.1.0')
 xkbcommon = dependency('xkbcommon')
-udev = dependency('libudev')
 pixman = dependency('pixman-1')
 math = cc.find_library('m')
 rt = cc.find_library('rt')
@@ -138,7 +138,6 @@ wlr_deps = [
 	drm,
 	gbm,
 	xkbcommon,
-	udev,
 	pixman,
 	math,
 	rt,

meson_options.txt

@@ -4,3 +4,4 @@ option('examples', type: 'boolean', value: true, description: 'Build example app
 option('icon_directory', description: 'Location used to look for cursors (default: ${datadir}/icons)', type: 'string', value: '')
 option('renderers', type: 'array', choices: ['auto', 'gles2', 'vulkan'], value: ['auto'], description: 'Select built-in renderers')
 option('backends', type: 'array', choices: ['auto', 'drm', 'libinput', 'x11'], value: ['auto'], description: 'Select built-in backends')
+option('enum-backend', type: 'combo', choices: ['auto', 'disabled', 'udev'], value: 'udev', description: 'Select device enumeration backend')