wlroots/xwayland/xwayland.c
Kenny Levinsen 57f8cf9cd4 xwayland: Introduce xwayland_spawn_func_t
Spawning subprocesses is finicky, and the correct way to do it depends
on the current process state which we have no control of. Signal masks,
handlers, limits, scheduling and open file descriptors are a few
examples of things that inadvertently get inherited and cause issues for
either the parent or the child.

We introduced a temporary workaround against common issues by clearing
signal masks and signal handlers known to cause issues for Xwayland, but
this was only a bandaid.

Introduce xwayland_spawn_func_t, which allows the compositor to specify
an implementation of a process spawner that will be used to launch
Xwayland whenever needed. This spawner can then do any cleanup and
accounting as the compositor sees fit.

The spawner takes 4 arguments: The path to Xwayland, the arguments we
have constructed for Xwayland, the environment variables that must be
set for Xwayland, and the file descriptors that must have CLOEXEC
cleared after fork but before exec to be correctly inherited by
Xwayland.

A default implementation is provided both for convenience and as a
sample for implementers to look at.
2025-03-20 17:13:13 +01:00

230 lines
6.4 KiB
C

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#include <wlr/types/wlr_seat.h>
#include <wlr/util/log.h>
#include <wlr/xwayland/shell.h>
#include <wlr/xwayland/xwayland.h>
#include "sockets.h"
#include "xwayland/xwm.h"
struct wlr_xwayland_cursor {
uint8_t *pixels;
uint32_t stride;
uint32_t width;
uint32_t height;
int32_t hotspot_x;
int32_t hotspot_y;
};
static void handle_server_destroy(struct wl_listener *listener, void *data) {
struct wlr_xwayland *xwayland =
wl_container_of(listener, xwayland, server_destroy);
// Server is being destroyed so avoid destroying it once again.
xwayland->server = NULL;
wlr_xwayland_destroy(xwayland);
}
static void handle_server_start(struct wl_listener *listener, void *data) {
struct wlr_xwayland *xwayland =
wl_container_of(listener, xwayland, server_start);
if (xwayland->shell_v1 != NULL) {
wlr_xwayland_shell_v1_set_client(xwayland->shell_v1, xwayland->server->client);
}
}
static void xwayland_mark_ready(struct wlr_xwayland *xwayland) {
assert(xwayland->server->wm_fd[0] >= 0);
xwayland->xwm = xwm_create(xwayland, xwayland->server->wm_fd[0]);
if (!xwayland->xwm) {
return;
}
if (xwayland->seat) {
xwm_set_seat(xwayland->xwm, xwayland->seat);
}
if (xwayland->cursor != NULL) {
struct wlr_xwayland_cursor *cur = xwayland->cursor;
xwm_set_cursor(xwayland->xwm, cur->pixels, cur->stride, cur->width,
cur->height, cur->hotspot_x, cur->hotspot_y);
}
wl_signal_emit_mutable(&xwayland->events.ready, NULL);
}
static void handle_server_ready(struct wl_listener *listener, void *data) {
struct wlr_xwayland *xwayland =
wl_container_of(listener, xwayland, server_ready);
xwayland_mark_ready(xwayland);
}
static void handle_shell_destroy(struct wl_listener *listener, void *data) {
struct wlr_xwayland *xwayland =
wl_container_of(listener, xwayland, shell_destroy);
xwayland->shell_v1 = NULL;
}
void wlr_xwayland_destroy(struct wlr_xwayland *xwayland) {
if (!xwayland) {
return;
}
wl_signal_emit_mutable(&xwayland->events.destroy, NULL);
assert(wl_list_empty(&xwayland->events.destroy.listener_list));
assert(wl_list_empty(&xwayland->events.new_surface.listener_list));
assert(wl_list_empty(&xwayland->events.ready.listener_list));
assert(wl_list_empty(&xwayland->events.remove_startup_info.listener_list));
wl_list_remove(&xwayland->server_destroy.link);
wl_list_remove(&xwayland->server_start.link);
wl_list_remove(&xwayland->server_ready.link);
wl_list_remove(&xwayland->shell_destroy.link);
free(xwayland->cursor);
wlr_xwayland_set_seat(xwayland, NULL);
if (xwayland->own_server) {
wlr_xwayland_server_destroy(xwayland->server);
}
xwayland->server = NULL;
wlr_xwayland_shell_v1_destroy(xwayland->shell_v1);
xwm_destroy(xwayland->xwm);
free(xwayland);
}
struct wlr_xwayland *wlr_xwayland_create_with_server(struct wl_display *wl_display,
struct wlr_compositor *compositor, struct wlr_xwayland_server *server) {
struct wlr_xwayland *xwayland = calloc(1, sizeof(*xwayland));
if (!xwayland) {
return NULL;
}
xwayland->wl_display = wl_display;
xwayland->compositor = compositor;
wl_signal_init(&xwayland->events.destroy);
wl_signal_init(&xwayland->events.new_surface);
wl_signal_init(&xwayland->events.ready);
wl_signal_init(&xwayland->events.remove_startup_info);
xwayland->server = server;
xwayland->display_name = xwayland->server->display_name;
xwayland->server_destroy.notify = handle_server_destroy;
wl_signal_add(&xwayland->server->events.destroy, &xwayland->server_destroy);
xwayland->server_start.notify = handle_server_start;
wl_signal_add(&xwayland->server->events.start, &xwayland->server_start);
xwayland->server_ready.notify = handle_server_ready;
wl_signal_add(&xwayland->server->events.ready, &xwayland->server_ready);
wl_list_init(&xwayland->shell_destroy.link);
if (server->ready) {
xwayland_mark_ready(xwayland);
}
return xwayland;
}
struct wlr_xwayland *wlr_xwayland_create(struct wl_display *wl_display,
struct wlr_compositor *compositor, bool lazy, xwayland_spawn_func_t spawn_func) {
struct wlr_xwayland_shell_v1 *shell_v1 = wlr_xwayland_shell_v1_create(wl_display, 1);
if (shell_v1 == NULL) {
return NULL;
}
struct wlr_xwayland_server_options options = {
.lazy = lazy,
.enable_wm = true,
.spawn_handler = spawn_func,
#if HAVE_XCB_XFIXES_SET_CLIENT_DISCONNECT_MODE
.terminate_delay = lazy ? 10 : 0,
#endif
};
struct wlr_xwayland_server *server = wlr_xwayland_server_create(wl_display, &options);
if (server == NULL) {
goto error_shell_v1;
}
struct wlr_xwayland *xwayland = wlr_xwayland_create_with_server(wl_display, compositor, server);
if (xwayland == NULL) {
goto error_server;
}
xwayland->shell_v1 = shell_v1;
xwayland->own_server = true;
xwayland->shell_destroy.notify = handle_shell_destroy;
wl_signal_add(&xwayland->shell_v1->events.destroy, &xwayland->shell_destroy);
return xwayland;
error_server:
wlr_xwayland_server_destroy(server);
error_shell_v1:
wlr_xwayland_shell_v1_destroy(shell_v1);
return NULL;
}
void wlr_xwayland_set_cursor(struct wlr_xwayland *xwayland,
uint8_t *pixels, uint32_t stride, uint32_t width, uint32_t height,
int32_t hotspot_x, int32_t hotspot_y) {
if (xwayland->xwm != NULL) {
xwm_set_cursor(xwayland->xwm, pixels, stride, width, height,
hotspot_x, hotspot_y);
return;
}
free(xwayland->cursor);
xwayland->cursor = calloc(1, sizeof(*xwayland->cursor));
if (xwayland->cursor == NULL) {
return;
}
xwayland->cursor->pixels = pixels;
xwayland->cursor->stride = stride;
xwayland->cursor->width = width;
xwayland->cursor->height = height;
xwayland->cursor->hotspot_x = hotspot_x;
xwayland->cursor->hotspot_y = hotspot_y;
}
static void xwayland_handle_seat_destroy(struct wl_listener *listener,
void *data) {
struct wlr_xwayland *xwayland =
wl_container_of(listener, xwayland, seat_destroy);
wlr_xwayland_set_seat(xwayland, NULL);
}
void wlr_xwayland_set_seat(struct wlr_xwayland *xwayland,
struct wlr_seat *seat) {
if (xwayland->seat) {
wl_list_remove(&xwayland->seat_destroy.link);
}
xwayland->seat = seat;
if (xwayland->xwm) {
xwm_set_seat(xwayland->xwm, seat);
}
if (seat == NULL) {
return;
}
xwayland->seat_destroy.notify = xwayland_handle_seat_destroy;
wl_signal_add(&seat->events.destroy, &xwayland->seat_destroy);
}