cage: add -x flag to disable XWayland at runtime

Allows disabling XWayland support at runtime even when the binary was
built with it.

.github/workflows/main.yml

@@ -7,6 +7,8 @@ on:
 
 env:
   WLROOTS_VERSION: "0.20"
+  ALPINE_PACKAGES: "build-base xcb-util-wm-dev libseat-dev clang git eudev-dev mesa-dev libdrm-dev libinput-dev libxkbcommon-dev pixman-dev wayland-dev meson wayland-protocols xwayland-dev scdoc-doc hwdata libdisplay-info-dev"
+  ARCHLINUX_PACKAGES: "xcb-util-wm seatd git clang meson libinput libdrm mesa libxkbcommon wayland wayland-protocols xorg-server-xwayland scdoc libdisplay-info"
 
 jobs:
   compile:
@@ -26,20 +28,20 @@ jobs:
 
       - name: Install dependencies (Alpine)
         if: "matrix.OS == 'alpine:edge'"
-        run: apk add build-base xcb-util-wm-dev libseat-dev clang git eudev-dev mesa-dev libdrm-dev libinput-dev libxkbcommon-dev pixman-dev wayland-dev meson wayland-protocols xwayland-dev scdoc-doc hwdata libdisplay-info-dev
+        run: apk add $ALPINE_PACKAGES
 
       - name: Install dependencies (Arch)
         if: "matrix.OS == 'archlinux:base-devel'"
         run: |
           pacman-key --init
-          pacman -Syu --noconfirm xcb-util-wm seatd git clang meson libinput libdrm mesa libxkbcommon wayland wayland-protocols xorg-server-xwayland scdoc libdisplay-info
+          pacman -Syu --noconfirm $ARCHLINUX_PACKAGES
 
       - name: Fetch wlroots as a subproject
         run: git clone https://gitlab.freedesktop.org/wlroots/wlroots.git subprojects/wlroots -b $WLROOTS_VERSION
 
       - name: Compile Cage (XWayland=${{ matrix.xwayland }})
         run: |
-          meson --fatal-meson-warnings --wrap-mode=nodownload \
+          meson setup --fatal-meson-warnings --wrap-mode=nodownload \
             build-${{ matrix.CC }}-${{matrix.xwayland }} \
             -Dwlroots:xwayland=${{ matrix.xwayland }}
           ninja -C build-${{ matrix.CC }}-${{matrix.xwayland }}
@@ -53,12 +55,12 @@ jobs:
       - name: Install dependencies
         run: |
           pacman-key --init
-          pacman -Syu --noconfirm xcb-util-wm seatd git clang meson libinput libdrm mesa libxkbcommon wayland wayland-protocols xorg-server-xwayland scdoc hwdata libdisplay-info
+          pacman -Syu --noconfirm $ARCHLINUX_PACKAGES
       - name: Fetch wlroots as a subproject
         run: git clone https://gitlab.freedesktop.org/wlroots/wlroots.git subprojects/wlroots -b $WLROOTS_VERSION
       - name: Check for formatting changes
         run: |
-          meson --wrap-mode=nodownload build-clang-format -Dwlroots:xwayland=enabled
+          meson setup --wrap-mode=nodownload build-clang-format -Dwlroots:xwayland=enabled
           ninja -C build-clang-format clang-format-check
 
   scan-build:
@@ -72,10 +74,10 @@ jobs:
       - name: Install dependencies
         run: |
           pacman-key --init
-          pacman -Syu --noconfirm xcb-util-wm seatd git clang meson libinput libdrm mesa libxkbcommon wayland wayland-protocols xorg-server-xwayland scdoc hwdata libdisplay-info
+          pacman -Syu --noconfirm $ARCHLINUX_PACKAGES
       - name: Fetch wlroots as a subproject
         run: git clone https://gitlab.freedesktop.org/wlroots/wlroots.git subprojects/wlroots -b $WLROOTS_VERSION
       - name: Run scan-build
         run: |
-          meson --wrap-mode=nodownload build-scan-build -Dwlroots:xwayland=enabled
+          meson setup --wrap-mode=nodownload build-scan-build -Dwlroots:xwayland=enabled
           ninja -C build-scan-build scan-build

cage.c

@@ -248,6 +248,7 @@ usage(FILE *file, const char *cage)
 		" -m last Use only the last connected output\n"
 		" -s\t Allow VT switching\n"
 		" -v\t Show the version number and exit\n"
+		" -x\t Disable XWayland\n"
 		"\n"
 		" Use -- when you want to pass arguments to APPLICATION\n",
 		cage);
@@ -256,8 +257,10 @@ usage(FILE *file, const char *cage)
 static bool
 parse_args(struct cg_server *server, int argc, char *argv[])
 {
+	server->enable_xwayland = true;
+
 	int c;
-	while ((c = getopt(argc, argv, "dDhm:sv")) != -1) {
+	while ((c = getopt(argc, argv, "dDhm:svx")) != -1) {
 		switch (c) {
 		case 'd':
 			server->xdg_decoration = true;
@@ -281,6 +284,9 @@ parse_args(struct cg_server *server, int argc, char *argv[])
 		case 'v':
 			fprintf(stdout, "Cage version " CAGE_VERSION "\n");
 			exit(0);
+		case 'x':
+			server->enable_xwayland = false;
+			break;
 		default:
 			usage(stderr, argv[0]);
 			return false;
@@ -562,35 +568,39 @@ main(int argc, char *argv[])
 
 #if CAGE_HAS_XWAYLAND
 	struct wlr_xcursor_manager *xcursor_manager = NULL;
-	struct wlr_xwayland *xwayland = wlr_xwayland_create(server.wl_display, compositor, true);
-	if (!xwayland) {
-		wlr_log(WLR_ERROR, "Cannot create XWayland server");
-	} else {
-		server.new_xwayland_surface.notify = handle_xwayland_surface_new;
-		wl_signal_add(&xwayland->events.new_surface, &server.new_xwayland_surface);
-
-		xcursor_manager = wlr_xcursor_manager_create(DEFAULT_XCURSOR, XCURSOR_SIZE);
-		if (!xcursor_manager) {
-			wlr_log(WLR_ERROR, "Cannot create XWayland XCursor manager");
-			ret = 1;
-			goto end;
-		}
-
-		if (setenv("DISPLAY", xwayland->display_name, true) < 0) {
-			wlr_log_errno(WLR_ERROR,
-				      "Unable to set DISPLAY for XWayland. Clients may not be able to connect");
+	struct wlr_xwayland *xwayland = NULL;
+	if (server.enable_xwayland) {
+		xwayland = wlr_xwayland_create(server.wl_display, compositor, true);
+		if (!xwayland) {
+			wlr_log(WLR_ERROR, "Cannot create XWayland server");
 		} else {
-			wlr_log(WLR_DEBUG, "XWayland is running on display %s", xwayland->display_name);
-		}
+			server.new_xwayland_surface.notify = handle_xwayland_surface_new;
+			wl_signal_add(&xwayland->events.new_surface, &server.new_xwayland_surface);
 
-		if (!wlr_xcursor_manager_load(xcursor_manager, 1)) {
-			wlr_log(WLR_ERROR, "Cannot load XWayland XCursor theme");
-		}
-		struct wlr_xcursor *xcursor = wlr_xcursor_manager_get_xcursor(xcursor_manager, DEFAULT_XCURSOR, 1);
-		if (xcursor) {
-			struct wlr_xcursor_image *image = xcursor->images[0];
-			wlr_xwayland_set_cursor(xwayland, wlr_xcursor_image_get_buffer(image), image->hotspot_x,
-						image->hotspot_y);
+			xcursor_manager = wlr_xcursor_manager_create(DEFAULT_XCURSOR, XCURSOR_SIZE);
+			if (!xcursor_manager) {
+				wlr_log(WLR_ERROR, "Cannot create XWayland XCursor manager");
+				ret = 1;
+				goto end;
+			}
+
+			if (setenv("DISPLAY", xwayland->display_name, true) < 0) {
+				wlr_log_errno(WLR_ERROR,
+					      "Unable to set DISPLAY for XWayland. Clients may not be able to connect");
+			} else {
+				wlr_log(WLR_DEBUG, "XWayland is running on display %s", xwayland->display_name);
+			}
+
+			if (!wlr_xcursor_manager_load(xcursor_manager, 1)) {
+				wlr_log(WLR_ERROR, "Cannot load XWayland XCursor theme");
+			}
+			struct wlr_xcursor *xcursor =
+				wlr_xcursor_manager_get_xcursor(xcursor_manager, DEFAULT_XCURSOR, 1);
+			if (xcursor) {
+				struct wlr_xcursor_image *image = xcursor->images[0];
+				wlr_xwayland_set_cursor(xwayland, wlr_xcursor_image_get_buffer(image), image->hotspot_x,
+							image->hotspot_y);
+			}
 		}
 	}
 #endif

seat.c

@@ -816,9 +816,9 @@ seat_create(struct cg_server *server, struct wlr_backend *backend)
 		return NULL;
 	}
 
-	seat->seat = wlr_seat_create(server->wl_display, "seat0");
+	seat->seat = wlr_seat_create(server->wl_display, "default");
 	if (!seat->seat) {
-		wlr_log(WLR_ERROR, "Cannot allocate seat0");
+		wlr_log(WLR_ERROR, "Cannot allocate seat");
 		free(seat);
 		return NULL;
 	}

server.h

@@ -72,6 +72,7 @@ struct cg_server {
 
 	bool xdg_decoration;
 	bool allow_vt_switch;
+	bool enable_xwayland;
 	bool return_app_code;
 	bool terminated;
 	enum wlr_log_importance log_level;