Merge pull request #487 from emersion/xwm-selection

xwm clipboard sync, 2nd edition

include/rootston/input.h

@@ -28,4 +28,6 @@ struct roots_seat *input_seat_from_wlr_seat(struct roots_input *input,
 
 bool input_view_has_focus(struct roots_input *input, struct roots_view *view);
 
+struct roots_seat *input_get_seat(struct roots_input *input, char *name);
+
 #endif

include/wlr/xwayland.h

@@ -4,6 +4,7 @@
 #include <time.h>
 #include <stdbool.h>
 #include <wlr/types/wlr_compositor.h>
+#include <wlr/types/wlr_seat.h>
 #include <xcb/xcb.h>
 
 #ifdef HAS_XCB_ICCCM
@@ -20,6 +21,7 @@ struct wlr_xwayland {
 	struct wl_client *client;
 	struct wl_display *wl_display;
 	struct wlr_compositor *compositor;
+	struct wlr_seat *seat;
 	time_t server_start;
 
 	struct wl_event_source *sigusr1_source;
@@ -175,4 +177,7 @@ void wlr_xwayland_surface_set_maximized(struct wlr_xwayland_surface *surface,
 void wlr_xwayland_surface_set_fullscreen(struct wlr_xwayland_surface *surface,
 		bool fullscreen);
 
+void wlr_xwayland_set_seat(struct wlr_xwayland *xwayland,
+		struct wlr_seat *seat);
+
 #endif

include/wlr/xwm.h

@@ -31,6 +31,13 @@ enum atom_name {
 	_NET_WM_STATE_MAXIMIZED_VERT,
 	_NET_WM_STATE_MAXIMIZED_HORZ,
 	WM_STATE,
+	CLIPBOARD,
+	WL_SELECTION,
+	TARGETS,
+	CLIPBOARD_MANAGER,
+	INCR,
+	TEXT,
+	TIMESTAMP,
 	ATOM_LAST,
 };
 
@@ -45,6 +52,7 @@ enum net_wm_state_action {
 struct wlr_xwm {
 	struct wlr_xwayland *xwayland;
 	struct wl_event_source *event_source;
+	struct wlr_seat *seat;
 
 	xcb_atom_t atoms[ATOM_LAST];
 	xcb_connection_t *xcb_conn;
@@ -55,6 +63,21 @@ struct wlr_xwm {
 	xcb_render_pictformat_t render_format_id;
 	xcb_cursor_t cursor;
 
+	// selection properties
+	xcb_window_t selection_window;
+	xcb_selection_request_event_t selection_request;
+	xcb_window_t selection_owner;
+	xcb_timestamp_t selection_timestamp;
+	int incr;
+	int data_source_fd;
+	int property_start;
+	xcb_get_property_reply_t *property_reply;
+	struct wl_event_source *property_source;
+	int flush_property_on_delete;
+	struct wl_array source_data;
+	xcb_atom_t selection_target;
+	bool selection_property_set;
+
 	struct wlr_xwayland_surface *focus_surface;
 
 	struct wl_list surfaces; // wlr_xwayland_surface::link
@@ -63,6 +86,7 @@ struct wlr_xwm {
 	const xcb_query_extension_reply_t *xfixes;
 
 	struct wl_listener compositor_surface_create;
+	struct wl_listener seat_selection_change;
 };
 
 struct wlr_xwm *xwm_create(struct wlr_xwayland *wlr_xwayland);
@@ -72,4 +96,10 @@ void xwm_destroy(struct wlr_xwm *xwm);
 void xwm_set_cursor(struct wlr_xwm *xwm, const uint8_t *pixels, uint32_t stride,
 	uint32_t width, uint32_t height, int32_t hotspot_x, int32_t hotspot_y);
 
+int xwm_handle_selection_event(struct wlr_xwm *xwm, xcb_generic_event_t *event);
+
+void xwm_selection_init(struct wlr_xwm *xwm);
+
+void xwm_set_seat(struct wlr_xwm *xwm, struct wlr_seat *seat);
+
 #endif

rootston/input.c

@@ -27,7 +27,7 @@ static const char *device_type(enum wlr_input_device_type type) {
 	return NULL;
 }
 
-static struct roots_seat *input_get_seat(struct roots_input *input, char *name) {
+struct roots_seat *input_get_seat(struct roots_input *input, char *name) {
 	struct roots_seat *seat = NULL;
 	wl_list_for_each(seat, &input->seats, link) {
 		if (strcmp(seat->seat->name, name) == 0) {

rootston/main.c

@@ -60,6 +60,9 @@ int main(int argc, char **argv) {
 	ready(NULL, NULL);
 #else
 	if (server.desktop->xwayland != NULL) {
+		struct roots_seat *xwayland_seat =
+			input_get_seat(server.input, ROOTS_CONFIG_DEFAULT_SEAT_NAME);
+		wlr_xwayland_set_seat(server.desktop->xwayland, xwayland_seat->seat);
 		wl_signal_add(&server.desktop->xwayland->events.ready,
 			&server.desktop->xwayland_ready);
 		server.desktop->xwayland_ready.notify = ready;

types/wlr_data_device.c

@@ -350,11 +350,11 @@ void wlr_seat_set_selection(struct wlr_seat *seat,
 static void data_device_set_selection(struct wl_client *client,
 		struct wl_resource *dd_resource, struct wl_resource *source_resource,
 		uint32_t serial) {
-	if (!source_resource) {
-		return;
+	struct wlr_data_source *source = NULL;
+	if (source_resource != NULL) {
+		source = wl_resource_get_user_data(source_resource);
 	}
 
-	struct wlr_data_source *source = wl_resource_get_user_data(source_resource);
 	struct wlr_seat_client *seat_client =
 		wl_resource_get_user_data(dd_resource);
 

xwayland/meson.build

@@ -1,6 +1,7 @@
 lib_wlr_xwayland = static_library(
 	'wlr_xwayland',
 	files(
+		'selection.c',
 		'sockets.c',
 		'xwayland.c',
 		'xwm.c',

xwayland/selection.c

@@ -0,0 +1,703 @@
+#define _XOPEN_SOURCE 700
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <assert.h>
+#include <xcb/xfixes.h>
+#include <fcntl.h>
+#include "wlr/util/log.h"
+#include "wlr/types/wlr_data_device.h"
+#include "wlr/xwm.h"
+
+static const size_t incr_chunk_size = 64 * 1024;
+
+static void xwm_send_selection_notify(struct wlr_xwm *xwm,
+		xcb_atom_t property) {
+	xcb_selection_notify_event_t selection_notify;
+
+	memset(&selection_notify, 0, sizeof selection_notify);
+	selection_notify.response_type = XCB_SELECTION_NOTIFY;
+	selection_notify.sequence = 0;
+	selection_notify.time = xwm->selection_request.time;
+	selection_notify.requestor = xwm->selection_request.requestor;
+	selection_notify.selection = xwm->selection_request.selection;
+	selection_notify.target = xwm->selection_request.target;
+	selection_notify.property = property;
+
+	xcb_send_event(xwm->xcb_conn, 0, // propagate
+		xwm->selection_request.requestor,
+		XCB_EVENT_MASK_NO_EVENT, (char *)&selection_notify);
+}
+
+static int xwm_flush_source_data(struct wlr_xwm *xwm)
+{
+	xcb_change_property(xwm->xcb_conn,
+		XCB_PROP_MODE_REPLACE,
+		xwm->selection_request.requestor,
+		xwm->selection_request.property,
+		xwm->selection_target,
+		8, // format
+		xwm->source_data.size,
+		xwm->source_data.data);
+	xwm->selection_property_set = 1;
+	int length = xwm->source_data.size;
+	xwm->source_data.size = 0;
+
+	return length;
+}
+
+static int xwm_read_data_source(int fd, uint32_t mask, void *data) {
+	struct wlr_xwm *xwm = data;
+	void *p;
+
+	int current = xwm->source_data.size;
+	if (xwm->source_data.size < incr_chunk_size) {
+		p = wl_array_add(&xwm->source_data, incr_chunk_size);
+	} else {
+		p = (char *) xwm->source_data.data + xwm->source_data.size;
+	}
+
+	int available = xwm->source_data.alloc - current;
+
+	int len = read(fd, p, available);
+	if (len == -1) {
+		wlr_log(L_ERROR, "read error from data source: %m");
+		xwm_send_selection_notify(xwm, XCB_ATOM_NONE);
+		wl_event_source_remove(xwm->property_source);
+		xwm->property_source = NULL;
+		close(fd);
+		wl_array_release(&xwm->source_data);
+	}
+
+	wlr_log(L_DEBUG, "read %d (available %d, mask 0x%x) bytes: \"%.*s\"",
+			len, available, mask, len, (char *) p);
+
+	xwm->source_data.size = current + len;
+	if (xwm->source_data.size >= incr_chunk_size) {
+		if (!xwm->incr) {
+			wlr_log(L_DEBUG, "got %zu bytes, starting incr",
+					xwm->source_data.size);
+			xwm->incr = 1;
+			xcb_change_property(xwm->xcb_conn,
+					XCB_PROP_MODE_REPLACE,
+					xwm->selection_request.requestor,
+					xwm->selection_request.property,
+					xwm->atoms[INCR],
+					32, /* format */
+					1, &incr_chunk_size);
+			xwm->selection_property_set = 1;
+			xwm->flush_property_on_delete = 1;
+			wl_event_source_remove(xwm->property_source);
+			xwm->property_source = NULL;
+			xwm_send_selection_notify(xwm, xwm->selection_request.property);
+		} else if (xwm->selection_property_set) {
+			wlr_log(L_DEBUG, "got %zu bytes, waiting for "
+				"property delete", xwm->source_data.size);
+
+			xwm->flush_property_on_delete = 1;
+			wl_event_source_remove(xwm->property_source);
+			xwm->property_source = NULL;
+		} else {
+			wlr_log(L_DEBUG, "got %zu bytes, "
+				"property deleted, setting new property",
+				xwm->source_data.size);
+			xwm_flush_source_data(xwm);
+		}
+	} else if (len == 0 && !xwm->incr) {
+		wlr_log(L_DEBUG, "non-incr transfer complete");
+		/* Non-incr transfer all done. */
+		xwm_flush_source_data(xwm);
+		xwm_send_selection_notify(xwm, xwm->selection_request.property);
+		xcb_flush(xwm->xcb_conn);
+		wl_event_source_remove(xwm->property_source);
+		xwm->property_source = NULL;
+		close(fd);
+		wl_array_release(&xwm->source_data);
+		xwm->selection_request.requestor = XCB_NONE;
+	} else if (len == 0 && xwm->incr) {
+		wlr_log(L_DEBUG, "incr transfer complete");
+
+		xwm->flush_property_on_delete = 1;
+		if (xwm->selection_property_set) {
+			wlr_log(L_DEBUG, "got %zu bytes, waiting for "
+					"property delete", xwm->source_data.size);
+		} else {
+			wlr_log(L_DEBUG, "got %zu bytes, "
+					"property deleted, setting new property",
+					xwm->source_data.size);
+			xwm_flush_source_data(xwm);
+		}
+		xcb_flush(xwm->xcb_conn);
+		wl_event_source_remove(xwm->property_source);
+		xwm->property_source = NULL;
+		close(xwm->data_source_fd);
+		xwm->data_source_fd = -1;
+		close(fd);
+	} else {
+		wlr_log(L_DEBUG, "nothing happened, buffered the bytes");
+	}
+
+	return 1;
+}
+
+static void xwm_send_data(struct wlr_xwm *xwm, xcb_atom_t target,
+		const char *mime_type) {
+	struct wlr_data_source *source;
+	int p[2];
+
+	if (pipe(p) == -1) {
+		wlr_log(L_ERROR, "pipe failed: %m");
+		xwm_send_selection_notify(xwm, XCB_ATOM_NONE);
+		return;
+	}
+
+	fcntl(p[0], F_SETFD, FD_CLOEXEC);
+	fcntl(p[0], F_SETFL, O_NONBLOCK);
+	fcntl(p[1], F_SETFD, FD_CLOEXEC);
+	fcntl(p[1], F_SETFL, O_NONBLOCK);
+
+	wl_array_init(&xwm->source_data);
+	xwm->selection_target = target;
+	xwm->data_source_fd = p[0];
+	struct wl_event_loop *loop =
+		wl_display_get_event_loop(xwm->xwayland->wl_display);
+	xwm->property_source = wl_event_loop_add_fd(loop,
+		xwm->data_source_fd,
+		WL_EVENT_READABLE,
+		xwm_read_data_source,
+		xwm);
+
+	source = xwm->seat->selection_source;
+	source->send(source, mime_type, p[1]);
+	close(p[1]);
+}
+
+static void xwm_send_timestamp(struct wlr_xwm *xwm) {
+	xcb_change_property(xwm->xcb_conn,
+		XCB_PROP_MODE_REPLACE,
+		xwm->selection_request.requestor,
+		xwm->selection_request.property,
+		XCB_ATOM_INTEGER,
+		32, // format
+		1, &xwm->selection_timestamp);
+
+	xwm_send_selection_notify(xwm, xwm->selection_request.property);
+}
+
+static void xwm_send_targets(struct wlr_xwm *xwm) {
+	struct wlr_data_source *source = xwm->seat->selection_source;
+	size_t n = 2 + source->mime_types.size / sizeof(char *);
+	xcb_atom_t *targets = malloc(n * sizeof(xcb_atom_t));
+	if (targets == NULL) {
+		return;
+	}
+	targets[0] = xwm->atoms[TIMESTAMP];
+	targets[1] = xwm->atoms[TARGETS];
+
+	size_t i = 2;
+	char **mime_type_ptr;
+	wl_array_for_each(mime_type_ptr, &source->mime_types) {
+		char *mime_type = *mime_type_ptr;
+		xcb_atom_t atom;
+		if (strcmp(mime_type, "text/plain;charset=utf-8") == 0) {
+			atom = xwm->atoms[UTF8_STRING];
+		} else if (strcmp(mime_type, "text/plain") == 0) {
+			atom = xwm->atoms[TEXT];
+		} else {
+			xcb_intern_atom_cookie_t cookie =
+				xcb_intern_atom(xwm->xcb_conn, 0, strlen(mime_type), mime_type);
+			xcb_intern_atom_reply_t *reply =
+				xcb_intern_atom_reply(xwm->xcb_conn, cookie, NULL);
+			if (reply == NULL) {
+				--n;
+				continue;
+			}
+			atom = reply->atom;
+			free(reply);
+		}
+		targets[i] = atom;
+		++i;
+	}
+
+	xcb_change_property(xwm->xcb_conn,
+		XCB_PROP_MODE_REPLACE,
+		xwm->selection_request.requestor,
+		xwm->selection_request.property,
+		XCB_ATOM_ATOM,
+		32, // format
+		n, targets);
+
+	xwm_send_selection_notify(xwm, xwm->selection_request.property);
+
+	free(targets);
+}
+
+static void xwm_handle_selection_request(struct wlr_xwm *xwm,
+		xcb_generic_event_t *event) {
+	xcb_selection_request_event_t *selection_request =
+		(xcb_selection_request_event_t *) event;
+
+	if (selection_request->selection != xwm->atoms[CLIPBOARD]) {
+		xwm_send_selection_notify(xwm, XCB_ATOM_NONE);
+		return;
+	}
+
+	xwm->selection_request = *selection_request;
+	xwm->incr = 0;
+	xwm->flush_property_on_delete = 0;
+
+	if (selection_request->selection == xwm->atoms[CLIPBOARD_MANAGER]) {
+		// The wlroots clipboard should already have grabbed
+		// the first target, so just send selection notify
+		// now.  This isn't synchronized with the clipboard
+		// finishing getting the data, so there's a race here.
+		xwm_send_selection_notify(xwm, xwm->selection_request.property);
+		return;
+	}
+
+	if (xwm->seat->selection_source == NULL) {
+		wlr_log(L_DEBUG, "not handling selection request: "
+			"no selection source assigned to xwayland seat");
+		xwm_send_selection_notify(xwm, XCB_ATOM_NONE);
+		return;
+	}
+
+	// No xwayland surface focused, deny access to clipboard
+	if (xwm->focus_surface == NULL) {
+		wlr_log(L_DEBUG, "denying read access to clipboard: "
+			"no xwayland surface focused");
+		xwm_send_selection_notify(xwm, XCB_ATOM_NONE);
+		return;
+	}
+
+	if (selection_request->target == xwm->atoms[TARGETS]) {
+		xwm_send_targets(xwm);
+	} else if (selection_request->target == xwm->atoms[TIMESTAMP]) {
+		xwm_send_timestamp(xwm);
+	} else if (selection_request->target == xwm->atoms[UTF8_STRING]) {
+		xwm_send_data(xwm, selection_request->target, "text/plain;charset=utf-8");
+	} else if (selection_request->target == xwm->atoms[TEXT]) {
+		xwm_send_data(xwm, selection_request->target, "text/plain");
+	} else {
+		xcb_get_atom_name_cookie_t name_cookie =
+			xcb_get_atom_name(xwm->xcb_conn, selection_request->target);
+		xcb_get_atom_name_reply_t *name_reply =
+			xcb_get_atom_name_reply(xwm->xcb_conn, name_cookie, NULL);
+		if (name_reply == NULL) {
+			wlr_log(L_DEBUG, "not handling selection request: unknown atom");
+			xwm_send_selection_notify(xwm, XCB_ATOM_NONE);
+			return;
+		}
+		size_t len = xcb_get_atom_name_name_length(name_reply);
+		char *mime_type = malloc((len + 1) * sizeof(char));
+		if (mime_type == NULL) {
+			free(name_reply);
+			return;
+		}
+		memcpy(mime_type, xcb_get_atom_name_name(name_reply), len);
+		mime_type[len] = '\0';
+		xwm_send_data(xwm, selection_request->target, mime_type);
+		free(mime_type);
+		free(name_reply);
+	}
+}
+
+static int writable_callback(int fd, uint32_t mask, void *data) {
+	struct wlr_xwm *xwm = data;
+
+	unsigned char *property = xcb_get_property_value(xwm->property_reply);
+	int remainder = xcb_get_property_value_length(xwm->property_reply) -
+		xwm->property_start;
+
+	int len = write(fd, property + xwm->property_start, remainder);
+	if (len == -1) {
+		free(xwm->property_reply);
+		xwm->property_reply = NULL;
+		if (xwm->property_source) {
+			wl_event_source_remove(xwm->property_source);
+		}
+		xwm->property_source = NULL;
+		close(fd);
+		wlr_log(L_ERROR, "write error to target fd: %m");
+		return 1;
+	}
+
+	wlr_log(L_DEBUG, "wrote %d (chunk size %d) of %d bytes",
+		xwm->property_start + len,
+		len, xcb_get_property_value_length(xwm->property_reply));
+
+	xwm->property_start += len;
+	if (len == remainder) {
+		free(xwm->property_reply);
+		xwm->property_reply = NULL;
+		if (xwm->property_source) {
+			wl_event_source_remove(xwm->property_source);
+		}
+		xwm->property_source = NULL;
+
+		if (xwm->incr) {
+			xcb_delete_property(xwm->xcb_conn,
+				xwm->selection_window,
+				xwm->atoms[WL_SELECTION]);
+		} else {
+			wlr_log(L_DEBUG, "transfer complete");
+			close(fd);
+		}
+	}
+
+	return 1;
+}
+
+static void xwm_write_property(struct wlr_xwm *xwm,
+		xcb_get_property_reply_t *reply) {
+	xwm->property_start = 0;
+	xwm->property_reply = reply;
+	writable_callback(xwm->data_source_fd, WL_EVENT_WRITABLE, xwm);
+
+	if (xwm->property_reply) {
+		struct wl_event_loop *loop =
+			wl_display_get_event_loop(xwm->xwayland->wl_display);
+		xwm->property_source =
+			wl_event_loop_add_fd(loop,
+				xwm->data_source_fd,
+				WL_EVENT_WRITABLE,
+				writable_callback, xwm);
+	}
+}
+
+static void xwm_get_selection_data(struct wlr_xwm *xwm) {
+	xcb_get_property_cookie_t cookie =
+		xcb_get_property(xwm->xcb_conn,
+			1, // delete
+			xwm->selection_window,
+			xwm->atoms[WL_SELECTION],
+			XCB_GET_PROPERTY_TYPE_ANY,
+			0, // offset
+			0x1fffffff // length
+			);
+
+	xcb_get_property_reply_t *reply =
+		xcb_get_property_reply(xwm->xcb_conn, cookie, NULL);
+
+	if (reply == NULL) {
+		return;
+	} else if (reply->type == xwm->atoms[INCR]) {
+		xwm->incr = 1;
+		free(reply);
+	} else {
+		xwm->incr = 0;
+		// reply's ownership is transferred to wm, which is responsible
+		// for freeing it
+		xwm_write_property(xwm, reply);
+	}
+}
+
+struct x11_data_source {
+	struct wlr_data_source base;
+	struct wlr_xwm *xwm;
+	struct wl_array mime_types_atoms;
+};
+
+static void data_source_accept(struct wlr_data_source *source, uint32_t time,
+		const char *mime_type) {
+}
+
+static void data_source_send(struct wlr_data_source *base,
+		const char *requested_mime_type, int32_t fd) {
+	struct x11_data_source *source = (struct x11_data_source *)base;
+	struct wlr_xwm *xwm = source->xwm;
+
+	bool found = false;
+	xcb_atom_t mime_type_atom;
+	char **mime_type_ptr;
+	size_t i = 0;
+	wl_array_for_each(mime_type_ptr, &source->base.mime_types) {
+		char *mime_type = *mime_type_ptr;
+		if (strcmp(mime_type, requested_mime_type) == 0) {
+			found = true;
+			xcb_atom_t *atoms = source->mime_types_atoms.data;
+			mime_type_atom = atoms[i];
+			break;
+		}
+		++i;
+	}
+	if (!found) {
+		return;
+	}
+
+	xcb_convert_selection(xwm->xcb_conn,
+		xwm->selection_window,
+		xwm->atoms[CLIPBOARD],
+		mime_type_atom,
+		xwm->atoms[WL_SELECTION],
+		XCB_TIME_CURRENT_TIME);
+
+	xcb_flush(xwm->xcb_conn);
+
+	fcntl(fd, F_SETFL, O_WRONLY | O_NONBLOCK);
+	xwm->data_source_fd = fd;
+}
+
+static void data_source_cancel(struct wlr_data_source *source) {
+}
+
+static void xwm_get_selection_targets(struct wlr_xwm *xwm) {
+	// set the wayland clipboard selection to the copied selection
+
+	xcb_get_property_cookie_t cookie = xcb_get_property(xwm->xcb_conn,
+		1, // delete
+		xwm->selection_window,
+		xwm->atoms[WL_SELECTION],
+		XCB_GET_PROPERTY_TYPE_ANY,
+		0, // offset
+		4096 // length
+		);
+
+	xcb_get_property_reply_t *reply =
+		xcb_get_property_reply(xwm->xcb_conn, cookie, NULL);
+	if (reply == NULL) {
+		return;
+	}
+
+	if (reply->type != XCB_ATOM_ATOM) {
+		free(reply);
+		return;
+	}
+
+	struct x11_data_source *source = calloc(1, sizeof(struct x11_data_source));
+	if (source == NULL) {
+		free(reply);
+		return;
+	}
+
+	wl_signal_init(&source->base.events.destroy);
+	source->base.accept = data_source_accept;
+	source->base.send = data_source_send;
+	source->base.cancel = data_source_cancel;
+	source->xwm = xwm;
+
+	wl_array_init(&source->base.mime_types);
+	wl_array_init(&source->mime_types_atoms);
+	xcb_atom_t *value = xcb_get_property_value(reply);
+	for (uint32_t i = 0; i < reply->value_len; i++) {
+		char *mime_type = NULL;
+
+		if (value[i] == xwm->atoms[UTF8_STRING]) {
+			mime_type = strdup("text/plain;charset=utf-8");
+		} else if (value[i] == xwm->atoms[TEXT]) {
+			mime_type = strdup("text/plain");
+		} else if (value[i] != xwm->atoms[TARGETS] &&
+				value[i] != xwm->atoms[TIMESTAMP]) {
+			xcb_get_atom_name_cookie_t name_cookie =
+				xcb_get_atom_name(xwm->xcb_conn, value[i]);
+			xcb_get_atom_name_reply_t *name_reply =
+				xcb_get_atom_name_reply(xwm->xcb_conn, name_cookie, NULL);
+			if (name_reply == NULL) {
+				continue;
+			}
+			size_t len = xcb_get_atom_name_name_length(name_reply);
+			char *name = xcb_get_atom_name_name(name_reply); // not a C string
+			if (memchr(name, '/', len) != NULL) {
+				mime_type = malloc((len + 1) * sizeof(char));
+				if (mime_type == NULL) {
+					free(name_reply);
+					continue;
+				}
+				memcpy(mime_type, name, len);
+				mime_type[len] = '\0';
+			}
+			free(name_reply);
+		}
+
+		if (mime_type != NULL) {
+			char **mime_type_ptr =
+				wl_array_add(&source->base.mime_types, sizeof(*mime_type_ptr));
+			if (mime_type_ptr == NULL) {
+				break;
+			}
+			*mime_type_ptr = mime_type;
+
+			xcb_atom_t *atom_ptr =
+				wl_array_add(&source->mime_types_atoms, sizeof(*atom_ptr));
+			if (atom_ptr == NULL) {
+				break;
+			}
+			*atom_ptr = value[i];
+		}
+	}
+
+	wlr_seat_set_selection(xwm->seat, &source->base,
+		wl_display_next_serial(xwm->xwayland->wl_display));
+
+	free(reply);
+}
+
+static void xwm_handle_selection_notify(struct wlr_xwm *xwm,
+		xcb_generic_event_t *event) {
+	xcb_selection_notify_event_t *selection_notify =
+		(xcb_selection_notify_event_t *) event;
+
+	if (selection_notify->selection != xwm->atoms[CLIPBOARD]) {
+		return;
+	}
+
+	if (selection_notify->property == XCB_ATOM_NONE) {
+		wlr_log(L_ERROR, "convert selection failed");
+	} else if (selection_notify->target == xwm->atoms[TARGETS]) {
+		// No xwayland surface focused, deny access to clipboard
+		if (xwm->focus_surface == NULL) {
+			wlr_log(L_DEBUG, "denying write access to clipboard: "
+				"no xwayland surface focused");
+			return;
+		}
+
+		// This sets the Wayland clipboard (by calling wlr_seat_set_selection)
+		xwm_get_selection_targets(xwm);
+	} else {
+		xwm_get_selection_data(xwm);
+	}
+}
+
+static int xwm_handle_xfixes_selection_notify(struct wlr_xwm *xwm,
+		xcb_generic_event_t *event) {
+	xcb_xfixes_selection_notify_event_t *xfixes_selection_notify =
+		(xcb_xfixes_selection_notify_event_t *) event;
+
+	if (xfixes_selection_notify->selection != xwm->atoms[CLIPBOARD]) {
+		return 0;
+	}
+
+	if (xfixes_selection_notify->owner == XCB_WINDOW_NONE) {
+		if (xwm->selection_owner != xwm->selection_window) {
+			// A real X client selection went away, not our
+			// proxy selection
+			wlr_seat_set_selection(xwm->seat, NULL,
+				wl_display_next_serial(xwm->xwayland->wl_display));
+		}
+
+		xwm->selection_owner = XCB_WINDOW_NONE;
+		return 1;
+	}
+
+	xwm->selection_owner = xfixes_selection_notify->owner;
+
+	// We have to use XCB_TIME_CURRENT_TIME when we claim the
+	// selection, so grab the actual timestamp here so we can
+	// answer TIMESTAMP conversion requests correctly.
+	if (xfixes_selection_notify->owner == xwm->selection_window) {
+		xwm->selection_timestamp = xfixes_selection_notify->timestamp;
+		wlr_log(L_DEBUG, "our window, skipping");
+		return 1;
+	}
+
+	xwm->incr = 0;
+	// doing this will give a selection notify where we actually handle the sync
+	xcb_convert_selection(xwm->xcb_conn, xwm->selection_window,
+		xfixes_selection_notify->selection,
+		xwm->atoms[TARGETS],
+		xwm->atoms[WL_SELECTION],
+		xfixes_selection_notify->timestamp);
+
+	xcb_flush(xwm->xcb_conn);
+
+	return 1;
+}
+
+int xwm_handle_selection_event(struct wlr_xwm *xwm,
+		xcb_generic_event_t *event) {
+	if (xwm->seat == NULL) {
+		wlr_log(L_DEBUG, "not handling selection events:"
+			"no seat assigned to xwayland");
+		return 0;
+	}
+
+	switch (event->response_type & ~0x80) {
+	case XCB_SELECTION_NOTIFY:
+		xwm_handle_selection_notify(xwm, event);
+		return 1;
+	case XCB_SELECTION_REQUEST:
+		xwm_handle_selection_request(xwm, event);
+		return 1;
+	}
+
+	switch (event->response_type - xwm->xfixes->first_event) {
+	case XCB_XFIXES_SELECTION_NOTIFY:
+		// an X11 window has copied something to the clipboard
+		return xwm_handle_xfixes_selection_notify(xwm, event);
+	}
+
+	return 0;
+}
+
+void xwm_selection_init(struct wlr_xwm *xwm) {
+	uint32_t values[1], mask;
+
+	xwm->selection_request.requestor = XCB_NONE;
+
+	values[0] = XCB_EVENT_MASK_PROPERTY_CHANGE;
+	xwm->selection_window = xcb_generate_id(xwm->xcb_conn);
+	xcb_create_window(xwm->xcb_conn,
+		XCB_COPY_FROM_PARENT,
+		xwm->selection_window,
+		xwm->screen->root,
+		0, 0,
+		10, 10,
+		0,
+		XCB_WINDOW_CLASS_INPUT_OUTPUT,
+		xwm->screen->root_visual,
+		XCB_CW_EVENT_MASK, values);
+
+	xcb_set_selection_owner(xwm->xcb_conn,
+		xwm->selection_window,
+		xwm->atoms[CLIPBOARD_MANAGER],
+		XCB_TIME_CURRENT_TIME);
+
+	mask =
+		XCB_XFIXES_SELECTION_EVENT_MASK_SET_SELECTION_OWNER |
+		XCB_XFIXES_SELECTION_EVENT_MASK_SELECTION_WINDOW_DESTROY |
+		XCB_XFIXES_SELECTION_EVENT_MASK_SELECTION_CLIENT_CLOSE;
+	xcb_xfixes_select_selection_input(xwm->xcb_conn, xwm->selection_window,
+		xwm->atoms[CLIPBOARD], mask);
+}
+
+static void handle_seat_set_selection(struct wl_listener *listener,
+		void *data) {
+	struct wlr_seat *seat = data;
+	struct wlr_xwm *xwm =
+		wl_container_of(listener, xwm, seat_selection_change);
+	struct wlr_data_source *source = seat->selection_source;
+
+	if (source == NULL) {
+		if (xwm->selection_owner == xwm->selection_window) {
+			xcb_set_selection_owner(xwm->xcb_conn,
+				XCB_ATOM_NONE,
+				xwm->atoms[CLIPBOARD],
+				xwm->selection_timestamp);
+		}
+
+		return;
+	}
+
+	if (source->send == data_source_send) {
+		return;
+	}
+
+	xcb_set_selection_owner(xwm->xcb_conn,
+		xwm->selection_window,
+		xwm->atoms[CLIPBOARD],
+		XCB_TIME_CURRENT_TIME);
+}
+
+void xwm_set_seat(struct wlr_xwm *xwm, struct wlr_seat *seat) {
+	assert(xwm);
+	assert(seat);
+	if (xwm->seat) {
+		wl_list_remove(&xwm->seat_selection_change.link);
+		xwm->seat = NULL;
+	}
+
+	wl_signal_add(&seat->events.selection, &xwm->seat_selection_change);
+	xwm->seat_selection_change.notify = handle_seat_set_selection;
+	xwm->seat = seat;
+	handle_seat_set_selection(&xwm->seat_selection_change, seat);
+}

xwayland/xwayland.c

@@ -218,6 +218,10 @@ static int xserver_handle_ready(int signal_number, void *data) {
 		return 1;
 	}
 
+	if (wlr_xwayland->seat) {
+		xwm_set_seat(wlr_xwayland->xwm, wlr_xwayland->seat);
+	}
+
 	wl_event_source_remove(wlr_xwayland->sigusr1_source);
 	wlr_xwayland->sigusr1_source = NULL;
 
@@ -368,3 +372,12 @@ void wlr_xwayland_set_cursor(struct wlr_xwayland *wlr_xwayland,
 	wlr_xwayland->cursor->hotspot_x = hotspot_x;
 	wlr_xwayland->cursor->hotspot_y = hotspot_y;
 }
+
+void wlr_xwayland_set_seat(struct wlr_xwayland *xwayland,
+		struct wlr_seat *seat) {
+	xwayland->seat = seat;
+
+	if (xwayland->xwm) {
+		xwm_set_seat(xwayland->xwm, seat);
+	}
+}

xwayland/xwm.c

@@ -44,6 +44,13 @@ const char *atom_map[ATOM_LAST] = {
 	"_NET_WM_STATE_MAXIMIZED_VERT",
 	"_NET_WM_STATE_MAXIMIZED_HORZ",
 	"WM_STATE",
+	"CLIPBOARD",
+	"_WL_SELECTION",
+	"TARGETS",
+	"CLIPBOARD_MANAGER",
+	"INCR",
+	"TEXT",
+	"TIMESTAMP",
 };
 
 /* General helpers */
@@ -944,6 +951,11 @@ static int x11_event_handler(int fd, uint32_t mask, void *data) {
 			break;
 		}
 
+		if (xwm_handle_selection_event(xwm, event)) {
+			free(event);
+			continue;
+		}
+
 		switch (event->response_type & XCB_EVENT_RESPONSE_TYPE_MASK) {
 		case XCB_CREATE_NOTIFY:
 			xwm_handle_create_notify(xwm, (xcb_create_notify_event_t *)event);
@@ -1078,6 +1090,9 @@ void xwm_destroy(struct wlr_xwm *xwm) {
 	if (!xwm) {
 		return;
 	}
+	if (xwm->selection_window) {
+		xcb_destroy_window(xwm->xcb_conn, xwm->selection_window);
+	}
 	if (xwm->cursor) {
 		xcb_free_cursor(xwm->xcb_conn, xwm->cursor);
 	}
@@ -1115,15 +1130,12 @@ static void xwm_get_resources(struct wlr_xwm *xwm) {
 			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);
-
+		xcb_intern_atom_reply_t *reply =
+			xcb_intern_atom_reply(xwm->xcb_conn, cookies[i], &error);
 		if (reply && !error) {
 			xwm->atoms[i] = reply->atom;
 		}
-
 		free(reply);
 
 		if (error) {
@@ -1375,6 +1387,8 @@ struct wlr_xwm *xwm_create(struct wlr_xwayland *wlr_xwayland) {
 
 	xwm_set_net_active_window(xwm, XCB_WINDOW_NONE);
 
+	xwm_selection_init(xwm);
+
 	xwm->compositor_surface_create.notify = handle_compositor_surface_create;
 	wl_signal_add(&wlr_xwayland->compositor->events.create_surface,
 		&xwm->compositor_surface_create);