weston/src/xwayland/launcher.c

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/*
* Copyright © 2011 Intel Corporation
*
* Permission to use, copy, modify, distribute, and sell this software and
* its documentation for any purpose is hereby granted without fee, provided
* that the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name of the copyright holders not be used in
* advertising or publicity pertaining to distribution of the software
* without specific, written prior permission. The copyright holders make
* no representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
* RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
* CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include "xwayland.h"
#include "xserver-server-protocol.h"
static int
weston_xserver_handle_event(int listen_fd, uint32_t mask, void *data)
{
struct weston_xserver *mxs = data;
char display[8], s[8];
int sv[2], client_fd;
if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, sv) < 0) {
fprintf(stderr, "socketpair failed\n");
return 1;
}
mxs->process.pid = fork();
switch (mxs->process.pid) {
case 0:
/* SOCK_CLOEXEC closes both ends, so we need to unset
* the flag on the client fd. */
client_fd = dup(sv[1]);
if (client_fd < 0)
return 1;
snprintf(s, sizeof s, "%d", client_fd);
setenv("WAYLAND_SOCKET", s, 1);
snprintf(display, sizeof display, ":%d", mxs->display);
if (execl(XSERVER_PATH,
XSERVER_PATH,
display,
"-wayland",
"-rootless",
"-retro",
"-nolisten", "all",
"-terminate",
NULL) < 0)
fprintf(stderr, "exec failed: %m\n");
exit(-1);
default:
fprintf(stderr, "forked X server, pid %d\n", mxs->process.pid);
close(sv[1]);
mxs->client = wl_client_create(mxs->wl_display, sv[0]);
weston_watch_process(&mxs->process);
wl_event_source_remove(mxs->abstract_source);
wl_event_source_remove(mxs->unix_source);
break;
case -1:
fprintf(stderr, "failed to fork\n");
break;
}
return 1;
}
static void
weston_xserver_shutdown(struct weston_xserver *wxs)
{
char path[256];
snprintf(path, sizeof path, "/tmp/.X%d-lock", wxs->display);
unlink(path);
snprintf(path, sizeof path, "/tmp/.X11-unix/X%d", wxs->display);
unlink(path);
if (wxs->process.pid == 0) {
wl_event_source_remove(wxs->abstract_source);
wl_event_source_remove(wxs->unix_source);
}
close(wxs->abstract_fd);
close(wxs->unix_fd);
if (wxs->wm)
weston_wm_destroy(wxs->wm);
wxs->loop = NULL;
}
static void
weston_xserver_cleanup(struct weston_process *process, int status)
{
struct weston_xserver *mxs =
container_of(process, struct weston_xserver, process);
mxs->process.pid = 0;
mxs->client = NULL;
mxs->resource = NULL;
mxs->abstract_source =
wl_event_loop_add_fd(mxs->loop, mxs->abstract_fd,
WL_EVENT_READABLE,
weston_xserver_handle_event, mxs);
mxs->unix_source =
wl_event_loop_add_fd(mxs->loop, mxs->unix_fd,
WL_EVENT_READABLE,
weston_xserver_handle_event, mxs);
if (mxs->wm) {
fprintf(stderr, "xserver exited, code %d\n", status);
weston_wm_destroy(mxs->wm);
mxs->wm = NULL;
} else {
/* If the X server crashes before it binds to the
* xserver interface, shut down and don't try
* again. */
fprintf(stderr, "xserver crashing too fast: %d\n", status);
weston_xserver_shutdown(mxs);
}
}
static void
bind_xserver(struct wl_client *client,
void *data, uint32_t version, uint32_t id)
{
struct weston_xserver *wxs = data;
/* If it's a different client than the xserver we launched,
* don't start the wm. */
if (client != wxs->client)
return;
wxs->resource =
wl_client_add_object(client, &xserver_interface,
&xserver_implementation, id, wxs);
wxs->wm = weston_wm_create(wxs);
if (wxs->wm == NULL) {
fprintf(stderr, "failed to create wm\n");
}
xserver_send_listen_socket(wxs->resource, wxs->abstract_fd);
xserver_send_listen_socket(wxs->resource, wxs->unix_fd);
}
static int
bind_to_abstract_socket(int display)
{
struct sockaddr_un addr;
socklen_t size, name_size;
int fd;
fd = socket(PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (fd < 0)
return -1;
addr.sun_family = AF_LOCAL;
name_size = snprintf(addr.sun_path, sizeof addr.sun_path,
"%c/tmp/.X11-unix/X%d", 0, display);
size = offsetof(struct sockaddr_un, sun_path) + name_size;
if (bind(fd, (struct sockaddr *) &addr, size) < 0) {
fprintf(stderr, "failed to bind to @%s: %s\n",
addr.sun_path + 1, strerror(errno));
close(fd);
return -1;
}
if (listen(fd, 1) < 0) {
close(fd);
return -1;
}
return fd;
}
static int
bind_to_unix_socket(int display)
{
struct sockaddr_un addr;
socklen_t size, name_size;
int fd;
fd = socket(PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (fd < 0)
return -1;
addr.sun_family = AF_LOCAL;
name_size = snprintf(addr.sun_path, sizeof addr.sun_path,
"/tmp/.X11-unix/X%d", display) + 1;
size = offsetof(struct sockaddr_un, sun_path) + name_size;
unlink(addr.sun_path);
if (bind(fd, (struct sockaddr *) &addr, size) < 0) {
fprintf(stderr, "failed to bind to %s (%s)\n",
addr.sun_path, strerror(errno));
close(fd);
return -1;
}
if (listen(fd, 1) < 0) {
unlink(addr.sun_path);
close(fd);
return -1;
}
return fd;
}
static int
create_lockfile(int display, char *lockfile, size_t lsize)
{
char pid[16], *end;
int fd, size;
pid_t other;
snprintf(lockfile, lsize, "/tmp/.X%d-lock", display);
fd = open(lockfile, O_WRONLY | O_CLOEXEC | O_CREAT | O_EXCL, 0444);
if (fd < 0 && errno == EEXIST) {
fd = open(lockfile, O_CLOEXEC, O_RDONLY);
if (fd < 0 || read(fd, pid, 11) != 11) {
fprintf(stderr, "can't read lock file %s: %s\n",
lockfile, strerror(errno));
errno = EEXIST;
return -1;
}
other = strtol(pid, &end, 0);
if (end != pid + 10) {
fprintf(stderr, "can't parse lock file %s\n",
lockfile);
close(fd);
errno = EEXIST;
return -1;
}
if (kill(other, 0) < 0 && errno == ESRCH) {
/* stale lock file; unlink and try again */
fprintf(stderr,
"unlinking stale lock file %s\n", lockfile);
close(fd);
if (unlink(lockfile))
/* If we fail to unlink, return EEXIST
so we try the next display number.*/
errno = EEXIST;
else
errno = EAGAIN;
return -1;
}
errno = EEXIST;
return -1;
} else if (fd < 0) {
fprintf(stderr, "failed to create lock file %s: %s\n",
lockfile, strerror(errno));
return -1;
}
/* Subtle detail: we use the pid of the wayland
* compositor, not the xserver in the lock file. */
size = snprintf(pid, sizeof pid, "%10d\n", getpid());
if (write(fd, pid, size) != size) {
unlink(lockfile);
close(fd);
return -1;
}
close(fd);
return 0;
}
static void
weston_xserver_destroy(struct wl_listener *l, void *data)
{
struct weston_xserver *wxs =
container_of(l, struct weston_xserver, destroy_listener);
if (!wxs)
return;
if (wxs->loop)
weston_xserver_shutdown(wxs);
free(wxs);
}
WL_EXPORT int
weston_xserver_init(struct weston_compositor *compositor)
{
struct wl_display *display = compositor->wl_display;
struct weston_xserver *mxs;
char lockfile[256], display_name[8];
mxs = malloc(sizeof *mxs);
memset(mxs, 0, sizeof *mxs);
mxs->process.cleanup = weston_xserver_cleanup;
mxs->wl_display = display;
mxs->compositor = compositor;
mxs->display = 0;
retry:
if (create_lockfile(mxs->display, lockfile, sizeof lockfile) < 0) {
if (errno == EAGAIN) {
goto retry;
} else if (errno == EEXIST) {
mxs->display++;
goto retry;
} else {
free(mxs);
return -1;
}
}
mxs->abstract_fd = bind_to_abstract_socket(mxs->display);
if (mxs->abstract_fd < 0 && errno == EADDRINUSE) {
mxs->display++;
unlink(lockfile);
goto retry;
}
mxs->unix_fd = bind_to_unix_socket(mxs->display);
if (mxs->unix_fd < 0) {
unlink(lockfile);
close(mxs->abstract_fd);
free(mxs);
return -1;
}
snprintf(display_name, sizeof display_name, ":%d", mxs->display);
fprintf(stderr, "xserver listening on display %s\n", display_name);
setenv("DISPLAY", display_name, 1);
mxs->loop = wl_display_get_event_loop(display);
mxs->abstract_source =
wl_event_loop_add_fd(mxs->loop, mxs->abstract_fd,
WL_EVENT_READABLE,
weston_xserver_handle_event, mxs);
mxs->unix_source =
wl_event_loop_add_fd(mxs->loop, mxs->unix_fd,
WL_EVENT_READABLE,
weston_xserver_handle_event, mxs);
wl_display_add_global(display, &xserver_interface, mxs, bind_xserver);
mxs->destroy_listener.notify = weston_xserver_destroy;
wl_signal_add(&compositor->destroy_signal, &mxs->destroy_listener);
return 0;
}