Merge pull request #119 from martinetd/xwayland

Xwayland

examples/compositor.c

@@ -19,6 +19,7 @@
 #include <wlr/types/wlr_seat.h>
 #include <wlr/types/wlr_data_device_manager.h>
 #include "wlr/types/wlr_compositor.h"
+#include <wlr/xwayland.h>
 #include <xkbcommon/xkbcommon.h>
 #include <wlr/util/log.h>
 #include "shared.h"
@@ -35,6 +36,7 @@ struct sample_state {
 	struct wlr_data_device_manager *data_device_manager;
 	struct wl_resource *focus;
 	struct wl_listener keyboard_bound;
+	struct wlr_xwayland *xwayland;
 	int keymap_fd;
 	size_t keymap_size;
 	uint32_t serial;
@@ -83,6 +85,10 @@ static void handle_output_frame(struct output_state *output, struct timespec *ts
 	wl_list_for_each(xdg_surface, &sample->xdg_shell->surfaces, link) {
 		output_frame_handle_surface(sample, wlr_output, ts, xdg_surface->surface);
 	}
+	struct wlr_x11_window *x11_window;
+	wl_list_for_each(x11_window, &sample->xwayland->displayable_windows, link) {
+		output_frame_handle_surface(sample, wlr_output, ts, x11_window->surface);
+	}
 
 	wlr_renderer_end(sample->renderer);
 	wlr_output_swap_buffers(wlr_output);
@@ -176,11 +182,13 @@ int main() {
 		free(keymap);
 		break;
 	}
+	state.xwayland = wlr_xwayland_create(compositor.display, state.wlr_compositor);
 
 	compositor.keyboard_key_cb = handle_keyboard_key;
 
 	wl_display_run(compositor.display);
 
+	wlr_xwayland_destroy(state.xwayland);
 	close(state.keymap_fd);
 	wlr_seat_destroy(state.wl_seat);
 	wlr_data_device_manager_destroy(state.data_device_manager);

include/wlr/types/wlr_compositor.h

@@ -9,6 +9,10 @@ struct wlr_compositor {
 	struct wlr_renderer *renderer;
 	struct wl_list surfaces;
 	struct wl_listener destroy_surface_listener;
+
+	struct {
+		struct wl_signal create_surface;
+	} events;
 };
 
 void wlr_compositor_destroy(struct wlr_compositor *wlr_compositor);

include/wlr/xwayland.h

@@ -0,0 +1,42 @@
+#ifndef _WLR_XWAYLAND_H
+#define _WLR_XWAYLAND_H
+#include <time.h>
+#include <sys/types.h>
+#include <stdbool.h>
+#include <wlr/types/wlr_compositor.h>
+#include <xcb/xcb.h>
+
+struct wlr_xwm;
+
+struct wlr_xwayland {
+	pid_t pid;
+	int display;
+	int x_fd[2], wl_fd[2], wm_fd[2];
+	struct wl_client *client;
+	struct wl_display *wl_display;
+	struct wlr_compositor *compositor;
+	time_t server_start;
+
+	struct wl_event_source *sigusr1_source;
+	struct wl_listener destroy_listener;
+	struct wlr_xwm *xwm;
+	struct wl_list displayable_windows;
+};
+
+struct wlr_x11_window {
+	xcb_window_t window_id;
+	uint32_t surface_id;
+	struct wl_list link;
+
+	struct wl_resource *surface;
+	struct wl_listener surface_destroy_listener;
+	int16_t x, y;
+	uint16_t width, height;
+	bool override_redirect;
+};
+
+void wlr_xwayland_destroy(struct wlr_xwayland *wlr_xwayland);
+struct wlr_xwayland *wlr_xwayland_create(struct wl_display *wl_display,
+		struct wlr_compositor *compositor);
+
+#endif

meson.build

@@ -32,6 +32,8 @@ libinput       = dependency('libinput')
 xkbcommon      = dependency('xkbcommon')
 udev           = dependency('libudev')
 pixman         = dependency('pixman-1')
+xcb            = dependency('xcb')
+xcb_composite  = dependency('xcb-composite')
 libcap         = dependency('libcap', required: false)
 systemd        = dependency('libsystemd', required: false)
 math           = cc.find_library('m', required: false)
@@ -50,6 +52,7 @@ subdir('render')
 subdir('types')
 subdir('util')
 subdir('xcursor')
+subdir('xwayland')
 
 wlr_deps = [
   wayland_server,
@@ -64,6 +67,8 @@ wlr_deps = [
   xkbcommon,
   udev,
   pixman,
+  xcb,
+  xcb_composite,
   libcap,
   systemd,
   math,
@@ -77,6 +82,7 @@ lib_wlr = library('wlroots', files('dummy.c'),
     lib_wlr_types,
     lib_wlr_util,
     lib_wlr_xcursor,
+    lib_wlr_xwayland,
   ],
   dependencies: wlr_deps,
   include_directories: wlr_inc)

types/wlr_compositor.c

@@ -22,6 +22,7 @@ static void wl_compositor_create_surface(struct wl_client *client,
 	wl_resource_add_destroy_listener(surface_resource, &surface->compositor_listener);
 
 	wl_list_insert(&compositor->surfaces, wl_resource_get_link(surface_resource));
+	wl_signal_emit(&compositor->events.create_surface, surface);
 }
 
 static void wl_compositor_create_region(struct wl_client *client,
@@ -80,5 +81,6 @@ struct wlr_compositor *wlr_compositor_create(struct wl_display *display,
 	compositor->renderer = renderer;
 	wl_list_init(&compositor->wl_resources);
 	wl_list_init(&compositor->surfaces);
+	wl_signal_init(&compositor->events.create_surface);
 	return compositor;
 }

types/wlr_surface.c

@@ -386,6 +386,7 @@ struct wlr_surface *wlr_surface_create(struct wl_resource *res,
 		wl_resource_post_no_memory(res);
 		return NULL;
 	}
+	wlr_log(L_DEBUG, "New wlr_surface %p (res %p)", surface, res);
 	surface->renderer = renderer;
 	surface->texture = wlr_render_texture_create(renderer);
 	surface->resource = res;

types/wlr_wl_shell.c

@@ -88,6 +88,7 @@ static void wl_shell_get_shell_surface(struct wl_client *client,
 	state->surface = surface;
 	struct wl_resource *shell_surface_resource = wl_resource_create(client,
 			&wl_shell_surface_interface, wl_resource_get_version(resource), id);
+	wlr_log(L_DEBUG, "New wl_shell %p (res %p)", state, shell_surface_resource);
 	wl_resource_set_implementation(shell_surface_resource,
 			&shell_surface_interface, state, destroy_shell_surface);
 	wl_list_insert(&wlr_wl_shell->surfaces, &state->link);

types/wlr_xdg_shell_v6.c

@@ -149,6 +149,7 @@ static void xdg_shell_get_xdg_surface(struct wl_client *client,
 	surface->surface = _surface;
 	surface->resource = wl_resource_create(client,
 		&zxdg_surface_v6_interface, wl_resource_get_version(_xdg_shell), id);
+	wlr_log(L_DEBUG, "new xdg_surface %p (res %p)", surface, surface->resource);
 	wl_resource_set_implementation(surface->resource,
 		&zxdg_surface_v6_implementation, surface, xdg_surface_destroy);
 	wl_list_insert(&xdg_shell->surfaces, &surface->link);

xwayland/meson.build

@@ -0,0 +1,7 @@
+lib_wlr_xwayland = static_library('wlr_xwayland', files(
+    'sockets.c',
+    'xwayland.c',
+    'xwm.c',
+  ),
+  include_directories: wlr_inc,
+  dependencies: [wayland_server, xcb, xcb_composite, pixman])

xwayland/sockets.c

@@ -0,0 +1,153 @@
+#define _XOPEN_SOURCE 700
+#include <stdlib.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <errno.h>
+#include "wlr/util/log.h"
+#include "sockets.h"
+
+static const char *lock_fmt = "/tmp/.X%d-lock";
+static const char *socket_dir = "/tmp/.X11-unix";
+static const char *socket_fmt = "/tmp/.X11-unix/X%d";
+
+static int open_socket(struct sockaddr_un *addr, size_t path_size) {
+	int fd, rc;
+	socklen_t size = offsetof(struct sockaddr_un, sun_path) + path_size + 1;
+
+	fd = socket(PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
+	if (fd < 0) {
+		wlr_log_errno(L_DEBUG, "Failed to create socket %c%s",
+			addr->sun_path[0] ? addr->sun_path[0] : '@',
+			addr->sun_path + 1);
+		return -1;
+	}
+
+	if (addr->sun_path[0]) {
+		unlink(addr->sun_path);
+	}
+	if (bind(fd, (struct sockaddr*)addr, size) < 0) {
+		rc = errno;
+		wlr_log_errno(L_DEBUG, "Failed to bind socket %c%s",
+			addr->sun_path[0] ? addr->sun_path[0] : '@',
+			addr->sun_path + 1);
+		goto cleanup;
+	}
+	if (listen(fd, 1) < 0) {
+		rc = errno;
+		wlr_log_errno(L_DEBUG, "Failed to listen to socket %c%s",
+			addr->sun_path[0] ? addr->sun_path[0] : '@',
+			addr->sun_path + 1);
+		goto cleanup;
+	}
+
+	return fd;
+
+cleanup:
+	close(fd);
+	if (addr->sun_path[0]) {
+		unlink(addr->sun_path);
+	}
+	errno = rc;
+	return -1;
+}
+
+static bool open_sockets(int socks[2], int display) {
+	struct sockaddr_un addr = { .sun_family = AF_LOCAL };
+	size_t path_size;
+
+	mkdir(socket_dir, 0777);
+
+	// TODO: non-linux apparently want another format
+	addr.sun_path[0] = 0;
+	path_size = snprintf(addr.sun_path + 1, sizeof(addr.sun_path) - 1, socket_fmt, display);
+	socks[0] = open_socket(&addr, path_size);
+	if (socks[0] < 0) {
+		return false;
+	}
+
+	path_size = snprintf(addr.sun_path, sizeof(addr.sun_path), socket_fmt, display);
+	socks[1] = open_socket(&addr, path_size);
+	if (socks[1] < 0) {
+		close(socks[0]);
+		socks[0] = -1;
+		return false;
+	}
+
+	return true;
+}
+
+void unlink_display_sockets(int display) {
+	char sun_path[64];
+
+	snprintf(sun_path, sizeof(sun_path), socket_fmt, display);
+	unlink(sun_path);
+
+	snprintf(sun_path, sizeof(sun_path), lock_fmt, display);
+	unlink(sun_path);
+}
+
+int open_display_sockets(int socks[2]) {
+	int lock_fd, display;
+	char lock_name[64];
+
+	for (display = 0; display <= 32; display++) {
+		snprintf(lock_name, sizeof(lock_name), lock_fmt, display);
+		if ((lock_fd = open(lock_name, O_WRONLY | O_CREAT | O_EXCL | O_CLOEXEC, 0444)) >= 0) {
+			if (!open_sockets(socks, display)) {
+				unlink(lock_name);
+				close(lock_fd);
+				continue;
+			}
+			char pid[12];
+			snprintf(pid, sizeof(pid), "%10d", getpid());
+			if (write(lock_fd, pid, sizeof(pid) - 1) != sizeof(pid) - 1) {
+				unlink(lock_name);
+				close(lock_fd);
+				continue;
+			}
+			close(lock_fd);
+			break;
+		}
+
+		if ((lock_fd = open(lock_name, O_RDONLY | O_CLOEXEC)) < 0) {
+			continue;
+		}
+
+		char pid[12] = { 0 }, *end_pid;
+		ssize_t bytes = read(lock_fd, pid, sizeof(pid) - 1);
+		close(lock_fd);
+
+		if (bytes != sizeof(pid) - 1) {
+			continue;
+		}
+		long int read_pid;
+		read_pid = strtol(pid, &end_pid, 10);
+		if (read_pid < 0 || read_pid > INT32_MAX || end_pid != pid + sizeof(pid) - 2) {
+			continue;
+		}
+		errno = 0;
+		if (kill((pid_t)read_pid, 0) != 0 && errno == ESRCH) {
+			if (unlink(lock_name) != 0) {
+				continue;
+			}
+			// retry
+			display--;
+			continue;
+		}
+	}
+
+	if (display > 32) {
+		wlr_log(L_ERROR, "No display available in the first 33");
+		return -1;
+	}
+
+	return display;
+}

xwayland/sockets.h

@@ -0,0 +1,7 @@
+#ifndef XWAYLAND_SOCKETS_H
+#define XWAYLAND_SOCKETS_H
+
+void unlink_display_sockets(int display);
+int open_display_sockets(int socks[2]);
+
+#endif

xwayland/xwayland.c

@@ -0,0 +1,250 @@
+#define _XOPEN_SOURCE 700
+#define _DEFAULT_SOURCE
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <wayland-server.h>
+#include "wlr/util/log.h"
+#include "wlr/xwayland.h"
+#include "sockets.h"
+#include "xwm.h"
+
+static void safe_close(int fd) {
+	if (fd >= 0) {
+		close(fd);
+	}
+}
+
+static int unset_cloexec(int fd) {
+	if (fcntl(fd, F_SETFD, 0) != 0) {
+		wlr_log_errno(L_ERROR, "fcntl() failed on fd %d", fd);
+		return -1;
+	}
+	return 0;
+}
+
+static int fill_arg(char ***argv, const char *fmt, ...) {
+	int len;
+	char **cur_arg = *argv;
+	va_list args;
+	va_start(args, fmt);
+	len = vsnprintf(NULL, 0, fmt, args) + 1;
+	va_end(args);
+	while (*cur_arg) {
+		cur_arg++;
+	}
+	*cur_arg = malloc(len);
+	if (!*cur_arg) {
+		return -1;
+	}
+	*argv = cur_arg;
+	va_start(args, fmt);
+	len = vsnprintf(*cur_arg, len, fmt, args);
+	va_end(args);
+	return len;
+}
+
+static void exec_xwayland(struct wlr_xwayland *wlr_xwayland) {
+	if (unset_cloexec(wlr_xwayland->x_fd[0]) ||
+			unset_cloexec(wlr_xwayland->x_fd[1]) ||
+			unset_cloexec(wlr_xwayland->wm_fd[1]) ||
+			unset_cloexec(wlr_xwayland->wl_fd[1])) {
+		exit(EXIT_FAILURE);
+	}
+
+	/* Make Xwayland signal us when it's ready */
+	signal(SIGUSR1, SIG_IGN);
+
+	char *argv[] = {
+		"Xwayland", NULL /* display, e.g. :1 */,
+		"-rootless", "-terminate",
+		"-listen", NULL /* x_fd[0] */,
+		"-listen", NULL /* x_fd[1] */,
+		"-wm", NULL /* wm_fd[1] */,
+		NULL };
+	char **cur_arg = argv;
+
+	if (fill_arg(&cur_arg, ":%d", wlr_xwayland->display) < 0 ||
+			fill_arg(&cur_arg, "%d", wlr_xwayland->x_fd[0]) < 0 ||
+			fill_arg(&cur_arg, "%d", wlr_xwayland->x_fd[1]) < 0 ||
+			fill_arg(&cur_arg, "%d", wlr_xwayland->wm_fd[1]) < 0) {
+		wlr_log_errno(L_ERROR, "alloc/print failure");
+		exit(EXIT_FAILURE);
+	}
+
+	const char *xdg_runtime = getenv("XDG_RUNTIME_DIR");
+	if (!xdg_runtime) {
+		wlr_log(L_ERROR, "XDG_RUNTIME_DIR is not set");
+		exit(EXIT_FAILURE);
+	}
+
+	if (clearenv()) {	    
+		wlr_log_errno(L_ERROR, "clearenv failed");
+		exit(EXIT_FAILURE);
+	}
+	setenv("XDG_RUNTIME_DIR", xdg_runtime, true);
+	char wayland_socket_str[16];
+	snprintf(wayland_socket_str, sizeof(wayland_socket_str), "%d", wlr_xwayland->wl_fd[1]);
+	setenv("WAYLAND_SOCKET", wayland_socket_str, true);
+
+	wlr_log(L_INFO, "WAYLAND_SOCKET=%d Xwayland :%d -rootless -terminate -listen %d -listen %d -wm %d",
+		wlr_xwayland->wl_fd[1], wlr_xwayland->display, wlr_xwayland->x_fd[0],
+		wlr_xwayland->x_fd[1], wlr_xwayland->wm_fd[1]);
+
+	// TODO: close stdout/err depending on log level
+
+	execvp("Xwayland", argv);
+}
+
+static bool wlr_xwayland_init(struct wlr_xwayland *wlr_xwayland,
+		struct wl_display *wl_display, struct wlr_compositor *compositor);
+static void wlr_xwayland_finish(struct wlr_xwayland *wlr_xwayland);
+
+static void xwayland_destroy_event(struct wl_listener *listener, void *data) {
+	struct wlr_xwayland *wlr_xwayland = wl_container_of(listener, wlr_xwayland, destroy_listener);
+
+	/* don't call client destroy */
+	wlr_xwayland->client = NULL;
+	wl_list_remove(&wlr_xwayland->destroy_listener.link);
+	wlr_xwayland_finish(wlr_xwayland);
+
+	if (time(NULL) - wlr_xwayland->server_start > 5) {
+		wlr_xwayland_init(wlr_xwayland, wlr_xwayland->wl_display,
+			wlr_xwayland->compositor);
+	}
+}
+
+static void wlr_xwayland_finish(struct wlr_xwayland *wlr_xwayland) {
+	if (!wlr_xwayland || wlr_xwayland->display == -1) {
+		return;
+	}
+	if (wlr_xwayland->client) {
+		wl_list_remove(&wlr_xwayland->destroy_listener.link);
+		wl_client_destroy(wlr_xwayland->client);
+	}
+	if (wlr_xwayland->sigusr1_source) {
+		wl_event_source_remove(wlr_xwayland->sigusr1_source);
+	}
+
+	xwm_destroy(wlr_xwayland->xwm);
+
+	safe_close(wlr_xwayland->x_fd[0]);
+	safe_close(wlr_xwayland->x_fd[1]);
+	safe_close(wlr_xwayland->wl_fd[0]);
+	safe_close(wlr_xwayland->wl_fd[1]);
+	safe_close(wlr_xwayland->wm_fd[0]);
+	safe_close(wlr_xwayland->wm_fd[1]);
+
+	unlink_display_sockets(wlr_xwayland->display);
+	wlr_xwayland->display = -1;
+	unsetenv("DISPLAY");
+	/* We do not kill the Xwayland process, it dies to broken pipe
+	 * after we close our side of the wm/wl fds. This is more reliable
+	 * than trying to kill something that might no longer be Xwayland.
+	 */
+	// TODO: figure how to wait for dying process though. Probably handle SIGCHILD
+}
+
+static int xserver_handle_ready(int signal_number, void *data) {
+	struct wlr_xwayland *wlr_xwayland = data;
+
+	wlr_log(L_DEBUG, "Xserver is ready");
+
+	wlr_xwayland->xwm = xwm_create(wlr_xwayland);
+	if (!wlr_xwayland->xwm) {
+		wlr_xwayland_finish(wlr_xwayland);
+		return 1;
+	}
+
+	wl_event_source_remove(wlr_xwayland->sigusr1_source);
+	wlr_xwayland->sigusr1_source = NULL;
+
+	char display_name[16];
+	snprintf(display_name, sizeof(display_name), ":%d", wlr_xwayland->display);
+	setenv("DISPLAY", display_name, true);
+
+	return 1; /* wayland event loop dispatcher's count */
+}
+
+static bool wlr_xwayland_init(struct wlr_xwayland *wlr_xwayland,
+		struct wl_display *wl_display, struct wlr_compositor *compositor) {
+	memset(wlr_xwayland, 0, sizeof(struct wlr_xwayland));
+	wlr_xwayland->wl_display = wl_display;
+	wlr_xwayland->compositor = compositor;
+	wlr_xwayland->x_fd[0] = wlr_xwayland->x_fd[1] = -1;
+	wlr_xwayland->wl_fd[0] = wlr_xwayland->wl_fd[1] = -1;
+	wlr_xwayland->wm_fd[0] = wlr_xwayland->wm_fd[1] = -1;
+	wl_list_init(&wlr_xwayland->displayable_windows);
+
+	wlr_xwayland->display = open_display_sockets(wlr_xwayland->x_fd);
+	if (wlr_xwayland->display < 0) {
+		wlr_xwayland_finish(wlr_xwayland);
+		return false;
+	}
+	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, wlr_xwayland->wl_fd) != 0 ||
+			socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, wlr_xwayland->wm_fd) != 0) {
+		wlr_log_errno(L_ERROR, "failed to create socketpair");
+		wlr_xwayland_finish(wlr_xwayland);
+		return false;
+	}
+
+	if ((wlr_xwayland->pid = fork()) == 0) {
+		exec_xwayland(wlr_xwayland);
+		wlr_log_errno(L_ERROR, "execvpe failed");
+		exit(EXIT_FAILURE);
+	}
+
+	if (wlr_xwayland->pid < 0) {
+		wlr_log_errno(L_ERROR, "fork failed");
+		wlr_xwayland_finish(wlr_xwayland);
+		return false;
+	}
+
+	/* close child fds */
+	close(wlr_xwayland->x_fd[0]);
+	close(wlr_xwayland->x_fd[1]);
+	close(wlr_xwayland->wl_fd[1]);
+	close(wlr_xwayland->wm_fd[1]);
+	wlr_xwayland->x_fd[0] = wlr_xwayland->x_fd[1] = -1;
+	wlr_xwayland->wl_fd[1] = wlr_xwayland->wm_fd[1] = -1;
+
+	wlr_xwayland->server_start = time(NULL);
+
+	if (!(wlr_xwayland->client = wl_client_create(wl_display, wlr_xwayland->wl_fd[0]))) {
+		wlr_log_errno(L_ERROR, "wl_client_create failed");
+		wlr_xwayland_finish(wlr_xwayland);
+		return false;
+	}
+	wlr_xwayland->wl_fd[0] = -1; /* not ours anymore */
+
+	wlr_xwayland->destroy_listener.notify = xwayland_destroy_event;
+	wl_client_add_destroy_listener(wlr_xwayland->client, &wlr_xwayland->destroy_listener);
+
+	struct wl_event_loop *loop = wl_display_get_event_loop(wl_display);
+	wlr_xwayland->sigusr1_source = wl_event_loop_add_signal(loop, SIGUSR1, xserver_handle_ready, wlr_xwayland);
+
+	return true;
+}
+
+void wlr_xwayland_destroy(struct wlr_xwayland *wlr_xwayland) {
+	wlr_xwayland_finish(wlr_xwayland);
+	free(wlr_xwayland);
+}
+
+struct wlr_xwayland *wlr_xwayland_create(struct wl_display *wl_display,
+		struct wlr_compositor *compositor) {
+	struct wlr_xwayland *wlr_xwayland = calloc(1, sizeof(struct wlr_xwayland));
+	if (wlr_xwayland_init(wlr_xwayland, wl_display, compositor)) {
+		return wlr_xwayland;
+	}
+	free(wlr_xwayland);
+	return NULL;
+}

xwayland/xwm.c

@@ -0,0 +1,360 @@
+#include <stdlib.h>
+#include <xcb/composite.h>
+#include "wlr/util/log.h"
+#include "wlr/types/wlr_surface.h"
+#include "wlr/xwayland.h"
+#include "xwm.h"
+
+/* General helpers */
+// TODO: replace this with hash table?
+static struct wlr_x11_window *lookup_window(struct wl_list *list, xcb_window_t window_id) {
+	struct wlr_x11_window *window;
+	wl_list_for_each(window, list, link) {
+		if (window->window_id == window_id) {
+			return window;
+		}
+	}
+	return NULL;
+}
+static struct wlr_x11_window *lookup_window_any(struct wlr_xwm *xwm, xcb_window_t window_id) {
+	struct wlr_x11_window *window;
+	if ((window = lookup_window(&xwm->xwayland->displayable_windows, window_id)) ||
+			(window = lookup_window(&xwm->unpaired_windows, window_id)) ||
+			(window = lookup_window(&xwm->new_windows, window_id))) {
+		return window;
+	}
+	return NULL;
+}
+
+static struct wlr_x11_window *wlr_x11_window_create(struct wlr_xwm *xwm,
+		xcb_window_t window_id, int16_t x, int16_t y,
+		uint16_t width, uint16_t height, bool override_redirect) {
+	struct wlr_x11_window *window;
+
+	window = calloc(1, sizeof(struct wlr_x11_window));
+	if (!window) {
+		wlr_log(L_ERROR, "Could not allocate wlr x11 window");
+		return NULL;
+	}
+	window->window_id = window_id;
+	window->x = x;
+	window->y = y;
+	window->width = width;
+	window->height = height;
+	window->override_redirect = override_redirect;
+	wl_list_insert(&xwm->new_windows, &window->link);
+	return window;
+}
+
+static void wlr_x11_window_destroy(struct wlr_x11_window *window) {
+	wl_list_remove(&window->link);
+	free(window);
+}
+
+/* xcb helpers */
+#define XCB_CALL(xwm, x) xcb_call(xwm, __PRETTY_FUNCTION__, __LINE__, x)
+static bool xcb_call(struct wlr_xwm *xwm, const char *func, uint32_t line,
+		xcb_void_cookie_t cookie) {
+	xcb_generic_error_t *error;
+	if (!(error = xcb_request_check(xwm->xcb_conn, cookie))) {
+		return true;
+	}
+
+	wlr_log(L_ERROR, "xcb call failed in %s:%u, x11 error code %d",
+		func, line, error->error_code);
+	free(error);
+	return false;
+}
+
+static void map_shell_surface(struct wlr_xwm *xwm, struct wlr_x11_window *window,
+		struct wlr_surface *surface) {
+	// get xcb geometry for depth = alpha channel
+	window->surface = surface->resource;
+
+	wl_list_remove(&window->link);
+	wl_list_insert(&xwm->xwayland->displayable_windows, &window->link);
+}
+
+/* xcb event handlers */
+static void handle_create_notify(struct wlr_xwm *xwm, xcb_create_notify_event_t *ev) {
+	wlr_log(L_DEBUG, "XCB_CREATE_NOTIFY (%u)", ev->window);
+	wlr_x11_window_create(xwm, ev->window, ev->x, ev->y,
+		ev->width, ev->height, ev->override_redirect);
+}
+
+static void handle_destroy_notify(struct wlr_xwm *xwm, xcb_destroy_notify_event_t *ev) {
+	struct wlr_x11_window *window;
+	wlr_log(L_DEBUG, "XCB_DESTROY_NOTIFY (%u)", ev->window);
+	if (!(window = lookup_window_any(xwm, ev->window))) {
+		return;
+	}
+	wlr_x11_window_destroy(window);
+}
+
+static void handle_configure_request(struct wlr_xwm *xwm, xcb_configure_request_event_t *ev) {
+	struct wlr_x11_window *window;
+	wlr_log(L_DEBUG, "XCB_CONFIGURE_REQUEST (%u) [%ux%u+%d,%d]", ev->window,
+		ev->width, ev->height, ev->x, ev->y);
+	if (!(window = lookup_window_any(xwm, ev->window))) {
+		return;
+	}
+
+	window->x = ev->x;
+	window->y = ev->y;
+	window->width = ev->width;
+	window->height = ev->height;
+	// handle parent/sibling?
+
+	uint32_t values[] = { ev->x, ev->y, ev->width, ev->height, 0 };
+	uint32_t mask = XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y |
+		XCB_CONFIG_WINDOW_WIDTH | XCB_CONFIG_WINDOW_HEIGHT |
+		XCB_CONFIG_WINDOW_BORDER_WIDTH;
+	xcb_configure_window(xwm->xcb_conn, ev->window, mask, values);
+}
+
+static void handle_map_request(struct wlr_xwm *xwm, xcb_map_request_event_t *ev) {
+	wlr_log(L_DEBUG, "XCB_MAP_REQUEST (%u)", ev->window);
+	XCB_CALL(xwm, xcb_change_window_attributes_checked(xwm->xcb_conn,
+			ev->window, XCB_CW_EVENT_MASK,
+			&(uint32_t){XCB_EVENT_MASK_FOCUS_CHANGE | XCB_EVENT_MASK_PROPERTY_CHANGE}));
+	XCB_CALL(xwm, xcb_map_window_checked(xwm->xcb_conn, ev->window));
+}
+
+static void handle_map_notify(struct wlr_xwm *xwm, xcb_map_notify_event_t *ev) {
+	struct wlr_x11_window *window;
+	wlr_log(L_DEBUG, "XCB_MAP_NOTIFY (%u)", ev->window);
+	if ((window = lookup_window_any(xwm, ev->window))) {
+		window->override_redirect = ev->override_redirect;
+	} else {
+		wlr_x11_window_create(xwm, ev->window, 0, 0, 1, 1, ev->override_redirect);
+	}
+}
+
+static void handle_unmap_notify(struct wlr_xwm *xwm, xcb_unmap_notify_event_t *ev) {
+	struct wlr_x11_window *window;
+	wlr_log(L_DEBUG, "XCB_UNMAP_NOTIFY (%u)", ev->window);
+	if (!(window = lookup_window_any(xwm, ev->window))) {
+		return;
+	}
+	// remove pointer to surface only?
+	wlr_x11_window_destroy(window);
+}
+
+static void handle_property_notify(struct wlr_xwm *xwm, xcb_property_notify_event_t *ev) {
+	wlr_log(L_DEBUG, "XCB_PROPERTY_NOTIFY (%u)", ev->window);
+	// TODO lookup window & get properties
+}
+
+static void handle_client_message(struct wlr_xwm *xwm, xcb_client_message_event_t *ev) {
+	wlr_log(L_DEBUG, "XCB_CLIENT_MESSAGE (%u)", ev->window);
+
+	if (ev->type == xwm->atoms[WL_SURFACE_ID]) {
+		struct wlr_x11_window *window;
+		struct wl_resource *resource;
+		window = lookup_window(&xwm->new_windows, ev->window);
+		if (!window) {
+			wlr_log(L_DEBUG, "client message WL_SURFACE_ID but no new window %u ?",
+				ev->window);
+			return;
+		}
+		window->surface_id = ev->data.data32[0];
+		/* Check if we got notified after wayland surface create event */
+		resource = wl_client_get_object(xwm->xwayland->client, window->surface_id);
+		if (resource) {
+			map_shell_surface(xwm, window, wl_resource_get_user_data(resource));
+		} else {
+			wl_list_remove(&window->link);
+			wl_list_insert(&xwm->unpaired_windows, &window->link);
+		}
+	}
+	wlr_log(L_DEBUG, "unhandled client message %u", ev->type);
+}
+
+/* This is in xcb/xcb_event.h, but pulling xcb-util just for a constant
+ * others redefine anyway is meh
+ */
+#define XCB_EVENT_RESPONSE_TYPE_MASK (0x7f)
+static int x11_event_handler(int fd, uint32_t mask, void *data) {
+	int count = 0;
+	xcb_generic_event_t *event;
+	struct wlr_xwm *xwm = data;
+
+	while ((event = xcb_poll_for_event(xwm->xcb_conn))) {
+		count++;
+		switch (event->response_type & XCB_EVENT_RESPONSE_TYPE_MASK) {
+		case XCB_CREATE_NOTIFY:
+			handle_create_notify(xwm, (xcb_create_notify_event_t *)event);
+			break;
+		case XCB_DESTROY_NOTIFY:
+			handle_destroy_notify(xwm, (xcb_destroy_notify_event_t *)event);
+			break;
+		case XCB_CONFIGURE_REQUEST:
+			handle_configure_request(xwm, (xcb_configure_request_event_t *)event);
+			break;
+		case XCB_MAP_REQUEST:
+			handle_map_request(xwm, (xcb_map_request_event_t *)event);
+			break;
+		case XCB_MAP_NOTIFY:
+			handle_map_notify(xwm, (xcb_map_notify_event_t *)event);
+			break;
+		case XCB_UNMAP_NOTIFY:
+			handle_unmap_notify(xwm, (xcb_unmap_notify_event_t *)event);
+			break;
+		case XCB_PROPERTY_NOTIFY:
+			handle_property_notify(xwm, (xcb_property_notify_event_t *)event);
+			break;
+		case XCB_CLIENT_MESSAGE:
+			handle_client_message(xwm, (xcb_client_message_event_t *)event);
+			break;
+		default:
+			wlr_log(L_DEBUG, "X11 event: %d",
+				event->response_type & XCB_EVENT_RESPONSE_TYPE_MASK);
+			break;
+		}
+	}
+
+	xcb_flush(xwm->xcb_conn);
+	return count;
+}
+
+static void create_surface_handler(struct wl_listener *listener, void *data) {
+	struct wlr_surface *surface = data;
+	struct wlr_xwm *xwm = wl_container_of(listener, xwm, surface_create_listener);
+	struct wlr_x11_window *window;
+	uint32_t surface_id;
+
+	if (wl_resource_get_client(surface->resource) != xwm->xwayland->client) {
+		return;
+	}
+
+	wlr_log(L_DEBUG, "New x11 surface: %p", surface);
+
+	surface_id = wl_resource_get_id(surface->resource);
+	wl_list_for_each(window, &xwm->unpaired_windows, link) {
+		if (window->surface_id == surface_id) {
+			map_shell_surface(xwm, window, surface);
+			xcb_flush(xwm->xcb_conn);
+			return;
+		}
+	}
+}
+
+static void xcb_get_resources(struct wlr_xwm *xwm) {
+	size_t i;
+	xcb_intern_atom_cookie_t cookies[ATOM_LAST];
+
+	for (i = 0; i < ATOM_LAST; i++) {
+		cookies[i] = xcb_intern_atom(xwm->xcb_conn, 0, strlen(atom_map[i]), atom_map[i]);
+	}
+	for (i = 0; i < ATOM_LAST; i++) {
+		xcb_intern_atom_reply_t *reply;
+		xcb_generic_error_t *error;
+
+		reply = xcb_intern_atom_reply(xwm->xcb_conn, cookies[i], &error);
+
+		if (reply && !error) {
+			xwm->atoms[i] = reply->atom;
+		}
+		if (reply) {
+			free(reply);
+		}
+		if (error) {
+			wlr_log(L_ERROR, "could not resolve atom %s, x11 error code %d",
+				atom_map[i], error->error_code);
+			free(error);
+			return;
+		}
+	}
+}
+
+static void xcb_init_wm(struct wlr_xwm *xwm) {
+	xcb_screen_iterator_t screen_iterator;
+	screen_iterator = xcb_setup_roots_iterator(xcb_get_setup(xwm->xcb_conn));
+	xwm->screen = screen_iterator.data;
+
+	xwm->window = xcb_generate_id(xwm->xcb_conn);
+
+	uint32_t values[] = {
+		XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY | 
+			XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT |
+			XCB_EVENT_MASK_PROPERTY_CHANGE,
+		/* xwm->cursor, */
+	};
+	XCB_CALL(xwm, xcb_change_window_attributes_checked(xwm->xcb_conn, xwm->screen->root,
+			XCB_CW_EVENT_MASK /* | XCB_CW_CURSOR */, values));
+	XCB_CALL(xwm, xcb_composite_redirect_subwindows_checked(xwm->xcb_conn,
+			xwm->screen->root, XCB_COMPOSITE_REDIRECT_MANUAL));
+
+	XCB_CALL(xwm, xcb_create_window_checked(xwm->xcb_conn, XCB_COPY_FROM_PARENT,
+			xwm->window, xwm->screen->root, 0, 0, 1, 1, 0,
+			XCB_WINDOW_CLASS_INPUT_OUTPUT, xwm->screen->root_visual,
+			XCB_CW_EVENT_MASK, (uint32_t[]){XCB_EVENT_MASK_PROPERTY_CHANGE}));
+	xcb_atom_t supported[] = {
+		xwm->atoms[NET_WM_STATE],
+	};
+	XCB_CALL(xwm, xcb_change_property_checked(xwm->xcb_conn, XCB_PROP_MODE_REPLACE,
+			xwm->screen->root, xwm->atoms[NET_SUPPORTED], XCB_ATOM_ATOM,
+			32, sizeof(supported)/sizeof(*supported), supported));
+
+	XCB_CALL(xwm, xcb_set_selection_owner_checked(xwm->xcb_conn, xwm->window,
+			xwm->atoms[WM_S0], XCB_CURRENT_TIME));
+	XCB_CALL(xwm, xcb_set_selection_owner_checked(xwm->xcb_conn, xwm->window,
+			xwm->atoms[NET_WM_S0], XCB_CURRENT_TIME));
+	xcb_flush(xwm->xcb_conn);
+}
+
+void xwm_destroy(struct wlr_xwm *xwm) {
+	if (!xwm) {
+		return;
+	}
+	if (xwm->event_source) {
+		wl_event_source_remove(xwm->event_source);
+	}
+	struct wlr_x11_window *window, *tmp;
+	wl_list_for_each_safe(window, tmp, &xwm->xwayland->displayable_windows, link) {
+		wlr_x11_window_destroy(window);
+	}
+	wl_list_for_each_safe(window, tmp, &xwm->new_windows, link) {
+		wlr_x11_window_destroy(window);
+	}
+	wl_list_for_each_safe(window, tmp, &xwm->unpaired_windows, link) {
+		wlr_x11_window_destroy(window);
+	}
+	wl_list_remove(&xwm->surface_create_listener.link);
+	xcb_disconnect(xwm->xcb_conn);
+
+	free(xwm);
+}
+
+struct wlr_xwm *xwm_create(struct wlr_xwayland *wlr_xwayland) {
+	struct wlr_xwm *xwm = calloc(1, sizeof(struct wlr_xwm));
+	int rc;
+
+	xwm->xwayland = wlr_xwayland;
+	wl_list_init(&xwm->new_windows);
+	wl_list_init(&xwm->unpaired_windows);
+
+	xwm->xcb_conn = xcb_connect_to_fd(wlr_xwayland->wm_fd[0], NULL);
+	if ((rc = xcb_connection_has_error(xwm->xcb_conn))) {
+		wlr_log(L_ERROR, "xcb connect failed: %d", rc);
+		free(xwm);
+		return NULL;
+	}
+
+	struct wl_event_loop *event_loop = wl_display_get_event_loop(wlr_xwayland->wl_display);
+	xwm->event_source = wl_event_loop_add_fd(event_loop, wlr_xwayland->wm_fd[0],
+			WL_EVENT_READABLE, x11_event_handler, xwm);
+	// probably not needed
+	// wl_event_source_check(xwm->event_source);
+
+	// TODO more xcb init
+	// xcb_prefetch_extension_data(xwm->xcb_conn, &xcb_composite_id);
+	xcb_get_resources(xwm);
+	xcb_init_wm(xwm);
+
+	xwm->surface_create_listener.notify = create_surface_handler;
+	wl_signal_add(&wlr_xwayland->compositor->events.create_surface,
+			&xwm->surface_create_listener);
+
+	return xwm;
+}

xwayland/xwm.h

@@ -0,0 +1,84 @@
+#ifndef XWAYLAND_INTERNALS_H
+#define XWAYLAND_INTERNALS_H
+#include <wayland-server-core.h>
+#include <wlr/xwayland.h>
+
+/* wlc's atom list:
+   WL_SURFACE_ID,
+   WM_DELETE_WINDOW,
+   WM_TAKE_FOCUS,
+   WM_PROTOCOLS,
+   WM_NORMAL_HINTS,
+   MOTIF_WM_HINTS,
+   TEXT,
+   UTF8_STRING,
+   CLIPBOARD,
+   CLIPBOARD_MANAGER,
+   TARGETS,
+   PRIMARY,
+   WM_S0,
+   STRING,
+   WLC_SELECTION,
+   NET_WM_S0,
+   NET_WM_PID,
+   NET_WM_NAME,
+   NET_WM_STATE,
+   NET_WM_STATE_FULLSCREEN,
+   NET_WM_STATE_MODAL,
+   NET_WM_STATE_ABOVE,
+   NET_SUPPORTED,
+   NET_SUPPORTING_WM_CHECK,
+   NET_WM_WINDOW_TYPE,
+   NET_WM_WINDOW_TYPE_DESKTOP,
+   NET_WM_WINDOW_TYPE_DOCK,
+   NET_WM_WINDOW_TYPE_TOOLBAR,
+   NET_WM_WINDOW_TYPE_MENU,
+   NET_WM_WINDOW_TYPE_UTILITY,
+   NET_WM_WINDOW_TYPE_SPLASH,
+   NET_WM_WINDOW_TYPE_DIALOG,
+   NET_WM_WINDOW_TYPE_DROPDOWN_MENU,
+   NET_WM_WINDOW_TYPE_POPUP_MENU,
+   NET_WM_WINDOW_TYPE_TOOLTIP,
+   NET_WM_WINDOW_TYPE_NOTIFICATION,
+   NET_WM_WINDOW_TYPE_COMBO,
+   NET_WM_WINDOW_TYPE_DND,
+   NET_WM_WINDOW_TYPE_NORMAL,
+ */
+
+enum atom_name {
+	WL_SURFACE_ID,
+	WM_PROTOCOLS,
+	WM_S0,
+	NET_SUPPORTED,
+	NET_WM_S0,
+	NET_WM_STATE,
+	ATOM_LAST
+};
+
+static const char * const atom_map[ATOM_LAST] = {
+	"WL_SURFACE_ID",
+	"WM_PROTOCOLS",
+	"WM_S0",
+	"_NET_SUPPORTED",
+	"_NET_WM_S0",
+	"_NET_WM_STATE",
+};
+
+struct wlr_xwm {
+	struct wlr_xwayland *xwayland;
+	struct wl_event_source *event_source;
+	struct wl_listener surface_create_listener;
+
+	xcb_atom_t atoms[ATOM_LAST];
+	xcb_connection_t *xcb_conn;
+	xcb_screen_t *screen;
+	xcb_window_t window;
+
+	struct wl_list new_windows;
+	struct wl_list unpaired_windows;
+};
+
+void xwm_destroy(struct wlr_xwm *xwm);
+struct wlr_xwm *xwm_create(struct wlr_xwayland *wlr_xwayland);
+
+#endif