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mutter/src/wayland/weston-launch.c

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/*
* Copyright © 2012 Benjamin Franzke
*
* 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <poll.h>
#include <errno.h>
#include <error.h>
#include <getopt.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/signalfd.h>
#include <signal.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>
#include <termios.h>
#include <linux/vt.h>
#include <linux/major.h>
#include <linux/kd.h>
#include <pwd.h>
#include <grp.h>
#include <xf86drm.h>
#include <systemd/sd-login.h>
#include "weston-launch.h"
#define MAX_ARGV_SIZE 256
#define DRM_MAJOR 226
enum vt_state {
VT_HAS_VT,
VT_PENDING_CONFIRM,
VT_NOT_HAVE_VT,
};
struct weston_launch {
int tty;
int ttynr;
int sock[2];
struct passwd *pw;
int signalfd;
pid_t child;
int verbose;
struct termios terminal_attributes;
int kb_mode;
enum vt_state vt_state;
unsigned vt;
int drm_fd;
};
union cmsg_data { unsigned char b[4]; int fd; };
static void quit (struct weston_launch *wl, int status);
static int
weston_launch_allowed(struct weston_launch *wl)
{
char *session, *seat;
int err;
if (getuid() == 0)
return 1;
err = sd_pid_get_session(getpid(), &session);
if (err == 0 && session) {
if (sd_session_is_active(session) &&
sd_session_get_seat(session, &seat) == 0) {
free(seat);
free(session);
return 1;
}
free(session);
}
return 0;
}
static int
setup_launcher_socket(struct weston_launch *wl)
{
if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, wl->sock) < 0)
error(1, errno, "socketpair failed");
fcntl(wl->sock[0], F_SETFD, O_CLOEXEC);
return 0;
}
static int
setup_signals(struct weston_launch *wl)
{
int ret;
sigset_t mask;
struct sigaction sa;
memset(&sa, 0, sizeof sa);
sa.sa_handler = SIG_DFL;
sa.sa_flags = SA_NOCLDSTOP | SA_RESTART;
ret = sigaction(SIGCHLD, &sa, NULL);
assert(ret == 0);
sa.sa_handler = SIG_IGN;
sa.sa_flags = 0;
sigaction(SIGHUP, &sa, NULL);
ret = sigemptyset(&mask);
assert(ret == 0);
sigaddset(&mask, SIGCHLD);
sigaddset(&mask, SIGINT);
sigaddset(&mask, SIGTERM);
sigaddset(&mask, SIGUSR1);
ret = sigprocmask(SIG_BLOCK, &mask, NULL);
assert(ret == 0);
wl->signalfd = signalfd(-1, &mask, SFD_NONBLOCK | SFD_CLOEXEC);
if (wl->signalfd < 0)
return -errno;
return 0;
}
static void
setenv_fd(const char *env, int fd)
{
char buf[32];
snprintf(buf, sizeof buf, "%d", fd);
setenv(env, buf, 1);
}
static int
handle_confirm_vt_switch(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
{
struct weston_launcher_reply reply;
reply.header.opcode = WESTON_LAUNCHER_CONFIRM_VT_SWITCH;
reply.ret = -1;
if (wl->vt_state != VT_PENDING_CONFIRM) {
error(0, 0, "unexpected CONFIRM_VT_SWITCH");
goto out;
}
if (wl->drm_fd != -1) {
int ret;
ret = drmDropMaster(wl->drm_fd);
if (ret < 0) {
fprintf(stderr, "failed to drop DRM master: %m\n");
} else if (wl->verbose) {
fprintf(stderr, "dropped DRM master for VT switch\n");
}
}
wl->vt_state = VT_NOT_HAVE_VT;
ioctl(wl->tty, VT_RELDISP, 1);
if (wl->verbose)
fprintf(stderr, "mutter-launcher: confirmed VT switch\n");
reply.ret = 0;
out:
do {
len = send(wl->sock[0], &reply, sizeof reply, 0);
} while (len < 0 && errno == EINTR);
if (len < 0)
return -1;
return 0;
}
static int
handle_activate_vt(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
{
struct weston_launcher_reply reply;
struct weston_launcher_activate_vt *message;
unsigned vt;
reply.header.opcode = WESTON_LAUNCHER_ACTIVATE_VT;
reply.ret = -1;
if (len != sizeof(*message)) {
error(0, 0, "missing value in activate_vt request");
goto out;
}
message = msg->msg_iov->iov_base;
/* Negative values mean that we're activating our own VT */
if (message->vt > 0)
vt = message->vt;
else
vt = wl->vt;
reply.ret = ioctl(wl->tty, VT_ACTIVATE, vt);
if (reply.ret < 0)
reply.ret = -errno;
if (wl->verbose)
fprintf(stderr, "mutter-launch: activate VT, ret: %d\n", reply.ret);
out:
do {
len = send(wl->sock[0], &reply, sizeof reply, 0);
} while (len < 0 && errno == EINTR);
if (len < 0)
return -1;
return 0;
}
static int
handle_open(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
{
struct weston_launcher_reply reply;
int fd = -1;
char control[CMSG_SPACE(sizeof(fd))];
struct cmsghdr *cmsg;
struct stat s;
struct msghdr nmsg;
struct iovec iov;
struct weston_launcher_open *message;
union cmsg_data *data;
int dev_major;
reply.header.opcode = WESTON_LAUNCHER_OPEN;
reply.ret = -1;
message = msg->msg_iov->iov_base;
if ((size_t)len < sizeof(*message))
goto err0;
/* Ensure path is null-terminated */
((char *) message)[len-1] = '\0';
if (stat(message->path, &s) < 0) {
reply.ret = -errno;
goto err0;
}
dev_major = major(s.st_rdev);
if (dev_major != INPUT_MAJOR &&
dev_major != DRM_MAJOR) {
fprintf(stderr, "Device %s is not an input or DRM device\n",
message->path);
reply.ret = -EPERM;
goto err0;
}
if (dev_major == DRM_MAJOR && wl->drm_fd != -1) {
fprintf(stderr, "Already have a DRM device open\n");
reply.ret = -EPERM;
goto err0;
}
fd = open(message->path, message->flags);
if (fd < 0) {
fprintf(stderr, "Error opening device %s: %m\n",
message->path);
reply.ret = -errno;
goto err0;
}
if (dev_major == DRM_MAJOR) {
wl->drm_fd = fd;
}
err0:
memset(&nmsg, 0, sizeof nmsg);
nmsg.msg_iov = &iov;
nmsg.msg_iovlen = 1;
if (fd != -1) {
nmsg.msg_control = control;
nmsg.msg_controllen = sizeof control;
cmsg = CMSG_FIRSTHDR(&nmsg);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
data = (union cmsg_data *) CMSG_DATA(cmsg);
data->fd = fd;
nmsg.msg_controllen = cmsg->cmsg_len;
reply.ret = 0;
}
iov.iov_base = &reply;
iov.iov_len = sizeof reply;
if (wl->verbose)
fprintf(stderr, "mutter-launch: opened %s: ret: %d, fd: %d\n",
message->path, reply.ret, fd);
do {
len = sendmsg(wl->sock[0], &nmsg, 0);
} while (len < 0 && errno == EINTR);
close(fd);
if (len < 0)
return -1;
return 0;
}
static int
handle_socket_msg(struct weston_launch *wl)
{
char control[CMSG_SPACE(sizeof(int))];
char buf[BUFSIZ];
struct msghdr msg;
struct iovec iov;
int ret = -1;
ssize_t len;
struct weston_launcher_message *message;
memset(&msg, 0, sizeof(msg));
iov.iov_base = buf;
iov.iov_len = sizeof buf;
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = control;
msg.msg_controllen = sizeof control;
do {
len = recvmsg(wl->sock[0], &msg, 0);
} while (len < 0 && errno == EINTR);
if (len < 1)
return -1;
message = (void *) buf;
switch (message->opcode) {
case WESTON_LAUNCHER_OPEN:
ret = handle_open(wl, &msg, len);
break;
case WESTON_LAUNCHER_CONFIRM_VT_SWITCH:
ret = handle_confirm_vt_switch(wl, &msg, len);
break;
case WESTON_LAUNCHER_ACTIVATE_VT:
ret = handle_activate_vt(wl, &msg, len);
break;
}
return ret;
}
static void
tty_reset(struct weston_launch *wl)
{
struct vt_mode mode = { 0 };
if (ioctl(wl->tty, KDSKBMODE, wl->kb_mode))
fprintf(stderr, "failed to restore keyboard mode: %m\n");
if (ioctl(wl->tty, KDSETMODE, KD_TEXT))
fprintf(stderr, "failed to set KD_TEXT mode on tty: %m\n");
if (tcsetattr(wl->tty, TCSANOW, &wl->terminal_attributes) < 0)
fprintf(stderr, "could not restore terminal to canonical mode\n");
mode.mode = VT_AUTO;
if (ioctl(wl->tty, VT_SETMODE, &mode) < 0)
fprintf(stderr, "could not reset vt handling\n");
}
static void
quit(struct weston_launch *wl, int status)
{
if (wl->child > 0)
kill(wl->child, SIGKILL);
close(wl->signalfd);
close(wl->sock[0]);
if (wl->drm_fd > 0)
close(wl->drm_fd);
tty_reset(wl);
exit(status);
}
static int
handle_vt_switch(struct weston_launch *wl)
{
struct weston_launcher_event message;
ssize_t len;
if (wl->vt_state == VT_HAS_VT) {
wl->vt_state = VT_PENDING_CONFIRM;
message.header.opcode = WESTON_LAUNCHER_SERVER_REQUEST_VT_SWITCH;
} else if (wl->vt_state == VT_NOT_HAVE_VT) {
wl->vt_state = VT_HAS_VT;
ioctl(wl->tty, VT_RELDISP, VT_ACKACQ);
if (wl->drm_fd != -1) {
int ret;
ret = drmSetMaster(wl->drm_fd);
if (ret < 0) {
fprintf(stderr, "failed to become DRM master: %m\n");
/* This is very, very bad, and the compositor will crash soon,
but oh well... */
} else if (wl->verbose) {
fprintf(stderr, "became DRM master after VT switch\n");
}
}
message.header.opcode = WESTON_LAUNCHER_SERVER_VT_ENTER;
} else
return -1;
message.detail = 0;
do {
len = send(wl->sock[0], &message, sizeof(message), 0);
} while (len < 0 && errno == EINTR);
return 0;
}
static int
handle_signal(struct weston_launch *wl)
{
struct signalfd_siginfo sig;
int pid, status, ret;
if (read(wl->signalfd, &sig, sizeof sig) != sizeof sig) {
error(0, errno, "reading signalfd failed");
return -1;
}
switch (sig.ssi_signo) {
case SIGCHLD:
pid = waitpid(-1, &status, 0);
if (pid == wl->child) {
wl->child = 0;
if (WIFEXITED(status))
ret = WEXITSTATUS(status);
else if (WIFSIGNALED(status))
/*
* If weston dies because of signal N, we
* return 10+N. This is distinct from
* weston-launch dying because of a signal
* (128+N).
*/
ret = 10 + WTERMSIG(status);
else
ret = 0;
quit(wl, ret);
}
break;
case SIGTERM:
case SIGINT:
if (wl->child)
kill(wl->child, sig.ssi_signo);
break;
case SIGUSR1:
return handle_vt_switch(wl);
default:
return -1;
}
return 0;
}
static int
setup_tty(struct weston_launch *wl)
{
struct stat buf;
struct termios raw_attributes;
struct vt_mode mode = { 0 };
char *session;
char path[PATH_MAX];
int ok;
ok = sd_pid_get_session(getpid(), &session);
if (ok < 0)
error(1, -ok, "could not determine current session");
ok = sd_session_get_vt(session, &wl->vt);
if (ok < 0)
error(1, -ok, "could not determine current TTY");
snprintf(path, PATH_MAX, "/dev/tty%u", wl->vt);
wl->tty = open(path, O_RDWR | O_NOCTTY | O_CLOEXEC);
if (wl->tty < 0)
error(1, errno, "failed to open tty");
if (fstat(wl->tty, &buf) < 0)
error(1, errno, "stat %s failed", path);
if (major(buf.st_rdev) != TTY_MAJOR)
error(1, 0, "invalid tty device: %s", path);
wl->ttynr = minor(buf.st_rdev);
if (tcgetattr(wl->tty, &wl->terminal_attributes) < 0)
error(1, errno, "could not get terminal attributes");
/* Ignore control characters and disable echo */
raw_attributes = wl->terminal_attributes;
cfmakeraw(&raw_attributes);
/* Fix up line endings to be normal (cfmakeraw hoses them) */
raw_attributes.c_oflag |= OPOST | OCRNL;
/* Don't generate ttou signals */
raw_attributes.c_oflag &= ~TOSTOP;
if (tcsetattr(wl->tty, TCSANOW, &raw_attributes) < 0)
error(1, errno, "could not put terminal into raw mode");
ioctl(wl->tty, KDGKBMODE, &wl->kb_mode);
ok = ioctl(wl->tty, KDSKBMODE, K_OFF);
if (ok < 0) {
ok = ioctl(wl->tty, KDSKBMODE, K_RAW);
if (ok < 0)
error(1, errno, "failed to set keyboard mode on tty");
}
ok = ioctl(wl->tty, KDSETMODE, KD_GRAPHICS);
if (ok < 0)
error(1, errno, "failed to set KD_GRAPHICS mode on tty");
wl->vt_state = VT_HAS_VT;
mode.mode = VT_PROCESS;
mode.relsig = SIGUSR1;
mode.acqsig = SIGUSR1;
ok = ioctl(wl->tty, VT_SETMODE, &mode);
if (ok < 0)
error(1, errno, "failed to take control of vt handling");
return 0;
}
static void
drop_privileges(struct weston_launch *wl)
{
if (setgid(wl->pw->pw_gid) < 0 ||
#ifdef HAVE_INITGROUPS
initgroups(wl->pw->pw_name, wl->pw->pw_gid) < 0 ||
#endif
setuid(wl->pw->pw_uid) < 0)
error(1, errno, "dropping privileges failed");
}
static void
launch_compositor(struct weston_launch *wl, int argc, char *argv[])
{
char command[PATH_MAX];
char *child_argv[MAX_ARGV_SIZE];
sigset_t mask;
int i;
if (wl->verbose)
printf("weston-launch: spawned weston with pid: %d\n", getpid());
drop_privileges(wl);
setenv_fd("WESTON_LAUNCHER_SOCK", wl->sock[1]);
setenv("LD_LIBRARY_PATH", LIBDIR, 1);
unsetenv("DISPLAY");
/* Do not give our signal mask to the new process. */
sigemptyset(&mask);
sigaddset(&mask, SIGTERM);
sigaddset(&mask, SIGCHLD);
sigaddset(&mask, SIGINT);
sigaddset(&mask, SIGUSR1);
sigprocmask(SIG_UNBLOCK, &mask, NULL);
snprintf (command, PATH_MAX, "%s \"$@\"", argv[0]);
child_argv[0] = wl->pw->pw_shell;
child_argv[1] = "-l";
child_argv[2] = "-c";
child_argv[3] = command;
for (i = 0; i < argc; ++i)
child_argv[4 + i] = argv[i];
child_argv[4 + i] = NULL;
execv(child_argv[0], child_argv);
error(1, errno, "exec failed");
}
static void
help(const char *name)
{
fprintf(stderr, "Usage: %s [args...] [-- [weston args..]]\n", name);
fprintf(stderr, " -u, --user Start session as specified username\n");
fprintf(stderr, " -v, --verbose Be verbose\n");
fprintf(stderr, " -h, --help Display this help message\n");
}
int
main(int argc, char *argv[])
{
struct weston_launch wl;
int i, c;
struct option opts[] = {
{ "verbose", no_argument, NULL, 'v' },
{ "help", no_argument, NULL, 'h' },
{ 0, 0, NULL, 0 }
};
memset(&wl, 0, sizeof wl);
wl.drm_fd = -1;
while ((c = getopt_long(argc, argv, "u:t::vh", opts, &i)) != -1) {
switch (c) {
case 'v':
wl.verbose = 1;
break;
case 'h':
help("mutter-launch");
exit(EXIT_FAILURE);
}
}
if ((argc - optind) > (MAX_ARGV_SIZE - 6))
error(1, E2BIG, "Too many arguments to pass to weston");
if (optind >= argc)
error(1, 0, "Expected program argument");
wl.pw = getpwuid(getuid());
if (wl.pw == NULL)
error(1, errno, "failed to get username");
if (!weston_launch_allowed(&wl))
error(1, 0, "Permission denied. You must run from an active and local (systemd) session.");
if (setup_tty(&wl) < 0)
exit(EXIT_FAILURE);
if (setup_launcher_socket(&wl) < 0)
exit(EXIT_FAILURE);
if (setup_signals(&wl) < 0)
exit(EXIT_FAILURE);
wl.child = fork();
if (wl.child == -1) {
error(1, errno, "fork failed");
exit(EXIT_FAILURE);
}
if (wl.child == 0)
launch_compositor(&wl, argc - optind, argv + optind);
close(wl.sock[1]);
while (1) {
struct pollfd fds[2];
int n;
fds[0].fd = wl.sock[0];
fds[0].events = POLLIN;
fds[1].fd = wl.signalfd;
fds[1].events = POLLIN;
n = poll(fds, 2, -1);
if (n < 0)
error(0, errno, "poll failed");
if (fds[0].revents & POLLIN)
handle_socket_msg(&wl);
if (fds[1].revents)
handle_signal(&wl);
}
return 0;
}
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