weston/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.
*/
#include "config.h"
#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"
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static int
handle_sigusr1(int signal_number, void *data)
{
struct weston_xserver *wxs = data;
/* We'd be safer if we actually had the struct
* signalfd_siginfo from the signalfd data and could verify
* this came from Xwayland.*/
wxs->wm = weston_wm_create(wxs, wxs->wm_fd);
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wl_event_source_remove(wxs->sigusr1_source);
return 1;
}
static int
weston_xserver_handle_event(int listen_fd, uint32_t mask, void *data)
{
struct weston_xserver *wxs = data;
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char display[8], s[8], abstract_fd[8], unix_fd[8], wm_fd[8];
int sv[2], wm[2], fd;
char *xserver = NULL;
struct weston_config_section *section;
if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, sv) < 0) {
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weston_log("wl connection socketpair failed\n");
return 1;
}
if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, wm) < 0) {
weston_log("X wm connection socketpair failed\n");
return 1;
}
wxs->process.pid = fork();
switch (wxs->process.pid) {
case 0:
/* SOCK_CLOEXEC closes both ends, so we need to unset
* the flag on the client fd. */
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fd = dup(sv[1]);
if (fd < 0)
goto fail;
snprintf(s, sizeof s, "%d", fd);
setenv("WAYLAND_SOCKET", s, 1);
snprintf(display, sizeof display, ":%d", wxs->display);
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fd = dup(wxs->abstract_fd);
if (fd < 0)
goto fail;
snprintf(abstract_fd, sizeof abstract_fd, "%d", fd);
fd = dup(wxs->unix_fd);
if (fd < 0)
goto fail;
snprintf(unix_fd, sizeof unix_fd, "%d", fd);
fd = dup(wm[1]);
if (fd < 0)
goto fail;
snprintf(wm_fd, sizeof wm_fd, "%d", fd);
section = weston_config_get_section(wxs->compositor->config,
"xwayland", NULL, NULL);
weston_config_section_get_string(section, "path",
&xserver, XSERVER_PATH);
/* Ignore SIGUSR1 in the child, which will make the X
* server send SIGUSR1 to the parent (weston) when
* it's done with initialization. During
* initialization the X server will round trip and
* block on the wayland compositor, so avoid making
* blocking requests (like xcb_connect_to_fd) until
* it's done with that. */
signal(SIGUSR1, SIG_IGN);
if (execl(xserver,
xserver,
display,
"-rootless",
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"-listen", abstract_fd,
"-listen", unix_fd,
"-wm", wm_fd,
"-terminate",
NULL) < 0)
weston_log("exec of '%s %s -rootless "
"-listen %s -listen %s -wm %s "
"-terminate' failed: %m\n",
xserver, display,
abstract_fd, unix_fd, wm_fd);
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fail:
_exit(EXIT_FAILURE);
default:
weston_log("forked X server, pid %d\n", wxs->process.pid);
close(sv[1]);
wxs->client = wl_client_create(wxs->wl_display, sv[0]);
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close(wm[1]);
wxs->wm_fd = wm[0];
weston_watch_process(&wxs->process);
wl_event_source_remove(wxs->abstract_source);
wl_event_source_remove(wxs->unix_source);
break;
case -1:
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weston_log( "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->wm = NULL;
}
wxs->loop = NULL;
}
static void
weston_xserver_cleanup(struct weston_process *process, int status)
{
struct weston_xserver *wxs =
container_of(process, struct weston_xserver, process);
wxs->process.pid = 0;
wxs->client = NULL;
wxs->resource = NULL;
wxs->abstract_source =
wl_event_loop_add_fd(wxs->loop, wxs->abstract_fd,
WL_EVENT_READABLE,
weston_xserver_handle_event, wxs);
wxs->unix_source =
wl_event_loop_add_fd(wxs->loop, wxs->unix_fd,
WL_EVENT_READABLE,
weston_xserver_handle_event, wxs);
if (wxs->wm) {
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weston_log("xserver exited, code %d\n", status);
weston_wm_destroy(wxs->wm);
wxs->wm = NULL;
} else {
/* If the X server crashes before it binds to the
* xserver interface, shut down and don't try
* again. */
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weston_log("xserver crashing too fast: %d\n", status);
weston_xserver_shutdown(wxs);
}
}
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) {
weston_log("failed to bind to @%s: %m\n", addr.sun_path + 1);
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) {
weston_log("failed to bind to %s: %m\n", addr.sun_path);
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) {
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weston_log("can't read lock file %s: %s\n",
lockfile, strerror(errno));
if (fd >= 0)
close (fd);
errno = EEXIST;
return -1;
}
other = strtol(pid, &end, 0);
if (end != pid + 10) {
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weston_log("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 */
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weston_log("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;
}
close(fd);
errno = EEXIST;
return -1;
} else if (fd < 0) {
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weston_log("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
module_init(struct weston_compositor *compositor,
int *argc, char *argv[])
{
struct wl_display *display = compositor->wl_display;
struct weston_xserver *wxs;
char lockfile[256], display_name[8];
wxs = zalloc(sizeof *wxs);
if (wxs == NULL)
return -1;
wxs->process.cleanup = weston_xserver_cleanup;
wxs->wl_display = display;
wxs->compositor = compositor;
wxs->display = 0;
retry:
if (create_lockfile(wxs->display, lockfile, sizeof lockfile) < 0) {
if (errno == EAGAIN) {
goto retry;
} else if (errno == EEXIST) {
wxs->display++;
goto retry;
} else {
free(wxs);
return -1;
}
}
wxs->abstract_fd = bind_to_abstract_socket(wxs->display);
if (wxs->abstract_fd < 0 && errno == EADDRINUSE) {
wxs->display++;
unlink(lockfile);
goto retry;
}
wxs->unix_fd = bind_to_unix_socket(wxs->display);
if (wxs->unix_fd < 0) {
unlink(lockfile);
close(wxs->abstract_fd);
free(wxs);
return -1;
}
snprintf(display_name, sizeof display_name, ":%d", wxs->display);
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weston_log("xserver listening on display %s\n", display_name);
setenv("DISPLAY", display_name, 1);
wxs->loop = wl_display_get_event_loop(display);
wxs->abstract_source =
wl_event_loop_add_fd(wxs->loop, wxs->abstract_fd,
WL_EVENT_READABLE,
weston_xserver_handle_event, wxs);
wxs->unix_source =
wl_event_loop_add_fd(wxs->loop, wxs->unix_fd,
WL_EVENT_READABLE,
weston_xserver_handle_event, wxs);
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wxs->sigusr1_source = wl_event_loop_add_signal(wxs->loop, SIGUSR1,
handle_sigusr1, wxs);
wxs->destroy_listener.notify = weston_xserver_destroy;
wl_signal_add(&compositor->destroy_signal, &wxs->destroy_listener);
return 0;
}