2 * Copyright © 2012 Benjamin Franzke
4 * Permission to use, copy, modify, distribute, and sell this software and
5 * its documentation for any purpose is hereby granted without fee, provided
6 * that the above copyright notice appear in all copies and that both that
7 * copyright notice and this permission notice appear in supporting
8 * documentation, and that the name of the copyright holders not be used in
9 * advertising or publicity pertaining to distribution of the software
10 * without specific, written prior permission. The copyright holders make
11 * no representations about the suitability of this software for any
12 * purpose. It is provided "as is" without express or implied warranty.
14 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
15 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
16 * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
17 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
18 * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
19 * CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
20 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
36 #include <sys/types.h>
37 #include <sys/ioctl.h>
40 #include <sys/socket.h>
41 #include <sys/epoll.h>
42 #include <sys/signalfd.h>
49 #include <linux/major.h>
53 #include <security/pam_appl.h>
57 #ifdef HAVE_SYSTEMD_LOGIN
58 #include <systemd/sd-login.h>
61 #include "weston-launch.h"
63 struct weston_launch {
78 union cmsg_data { unsigned char b[4]; int fd; };
86 n = getgroups(0, NULL);
89 fprintf(stderr, "Unable to retrieve groups: %m\n");
93 groups = malloc(n * sizeof(gid_t));
97 if (getgroups(n, groups) < 0) {
98 fprintf(stderr, "Unable to retrieve groups: %m\n");
106 weston_launch_allowed(struct weston_launch *wl)
111 #ifdef HAVE_SYSTEMD_LOGIN
112 char *session, *seat;
119 gr = getgrnam("weston-launch");
121 groups = read_groups();
123 for (i = 0; groups[i]; ++i) {
124 if (groups[i] == gr->gr_gid) {
133 #ifdef HAVE_SYSTEMD_LOGIN
134 err = sd_pid_get_session(getpid(), &session);
135 if (err == 0 && session) {
136 if (sd_session_is_active(session) &&
137 sd_session_get_seat(session, &seat) == 0) {
150 pam_conversation_fn(int msg_count,
151 const struct pam_message **messages,
152 struct pam_response **responses,
159 setup_pam(struct weston_launch *wl)
163 wl->pc.conv = pam_conversation_fn;
164 wl->pc.appdata_ptr = wl;
166 err = pam_start("login", wl->pw->pw_name, &wl->pc, &wl->ph);
167 if (err != PAM_SUCCESS) {
168 fprintf(stderr, "failed to start pam transaction: %d: %s\n",
169 err, pam_strerror(wl->ph, err));
173 err = pam_set_item(wl->ph, PAM_TTY, ttyname(wl->tty));
174 if (err != PAM_SUCCESS) {
175 fprintf(stderr, "failed to set PAM_TTY item: %d: %s\n",
176 err, pam_strerror(wl->ph, err));
180 err = pam_open_session(wl->ph, 0);
181 if (err != PAM_SUCCESS) {
182 fprintf(stderr, "failed to open pam session: %d: %s\n",
183 err, pam_strerror(wl->ph, err));
191 setup_launcher_socket(struct weston_launch *wl)
193 struct epoll_event ev;
195 if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, wl->sock) < 0)
196 error(1, errno, "socketpair failed");
198 fcntl(wl->sock[0], F_SETFD, O_CLOEXEC);
200 memset(&ev, 0, sizeof ev);
202 ev.data.fd = wl->sock[0];
203 if (epoll_ctl(wl->epollfd, EPOLL_CTL_ADD, ev.data.fd, &ev) < 0)
210 setup_signals(struct weston_launch *wl)
214 struct epoll_event ev;
216 memset(&sa, 0, sizeof sa);
217 sa.sa_handler = SIG_DFL;
218 sa.sa_flags = SA_NOCLDSTOP | SA_RESTART;
219 assert(sigaction(SIGCHLD, &sa, NULL) == 0);
221 assert(sigemptyset(&mask) == 0);
222 sigaddset(&mask, SIGCHLD);
223 sigaddset(&mask, SIGINT);
224 sigaddset(&mask, SIGTERM);
225 assert(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
227 wl->signalfd = signalfd(-1, &mask, SFD_NONBLOCK | SFD_CLOEXEC);
228 if (wl->signalfd < 0)
231 memset(&ev, 0, sizeof ev);
233 ev.data.fd = wl->signalfd;
234 if (epoll_ctl(wl->epollfd, EPOLL_CTL_ADD, ev.data.fd, &ev) < 0)
241 setenv_fd(const char *env, int fd)
245 snprintf(buf, sizeof buf, "%d", fd);
250 handle_setmaster(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
253 struct cmsghdr *cmsg;
254 struct weston_launcher_set_master *message;
255 union cmsg_data *data;
257 if (len != sizeof(*message)) {
258 error(0, 0, "missing value in setmaster request");
262 message = msg->msg_iov->iov_base;
264 cmsg = CMSG_FIRSTHDR(msg);
266 cmsg->cmsg_level != SOL_SOCKET ||
267 cmsg->cmsg_type != SCM_RIGHTS) {
268 error(0, 0, "invalid control message");
272 data = (union cmsg_data *) CMSG_DATA(cmsg);
273 if (data->fd == -1) {
274 error(0, 0, "missing drm fd in socket request");
278 if (message->set_master)
279 ret = drmSetMaster(data->fd);
281 ret = drmDropMaster(data->fd);
286 len = send(wl->sock[0], &ret, sizeof ret, 0);
287 } while (len < 0 && errno == EINTR);
295 handle_open(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
297 int fd = -1, ret = -1;
298 char control[CMSG_SPACE(sizeof(fd))];
299 struct cmsghdr *cmsg;
303 struct weston_launcher_open *message;
304 union cmsg_data *data;
306 message = msg->msg_iov->iov_base;
307 if ((size_t)len < sizeof(*message))
310 /* Ensure path is null-terminated */
311 ((char *) message)[len-1] = '\0';
313 if (stat(message->path, &s) < 0)
316 fd = open(message->path, message->flags);
320 if (major(s.st_rdev) != INPUT_MAJOR) {
327 memset(&nmsg, 0, sizeof nmsg);
331 nmsg.msg_control = control;
332 nmsg.msg_controllen = sizeof control;
333 cmsg = CMSG_FIRSTHDR(&nmsg);
334 cmsg->cmsg_level = SOL_SOCKET;
335 cmsg->cmsg_type = SCM_RIGHTS;
336 cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
337 data = (union cmsg_data *) CMSG_DATA(cmsg);
339 nmsg.msg_controllen = cmsg->cmsg_len;
343 iov.iov_len = sizeof ret;
346 fprintf(stderr, "weston-launch: opened %s: ret: %d, fd: %d\n",
347 message->path, ret, fd);
349 len = sendmsg(wl->sock[0], &nmsg, 0);
350 } while (len < 0 && errno == EINTR);
359 handle_socket_msg(struct weston_launch *wl)
361 char control[CMSG_SPACE(sizeof(int))];
367 struct weston_launcher_message *message;
369 memset(&msg, 0, sizeof(msg));
371 iov.iov_len = sizeof buf;
374 msg.msg_control = control;
375 msg.msg_controllen = sizeof control;
378 len = recvmsg(wl->sock[0], &msg, 0);
379 } while (len < 0 && errno == EINTR);
384 message = (void *) buf;
385 switch (message->opcode) {
386 case WESTON_LAUNCHER_OPEN:
387 ret = handle_open(wl, &msg, len);
389 case WESTON_LAUNCHER_DRM_SET_MASTER:
390 ret = handle_setmaster(wl, &msg, len);
398 quit(struct weston_launch *wl, int status)
406 err = pam_close_session(wl->ph, 0);
408 fprintf(stderr, "pam_close_session failed: %d: %s\n",
409 err, pam_strerror(wl->ph, err));
410 pam_end(wl->ph, err);
416 handle_signal(struct weston_launch *wl)
418 struct signalfd_siginfo sig;
421 if (read(wl->signalfd, &sig, sizeof sig) != sizeof sig) {
422 error(0, errno, "reading signalfd failed");
426 switch (sig.ssi_signo) {
428 pid = waitpid(-1, &status, 0);
429 if (pid == wl->child) {
431 quit(wl, WIFEXITED(status) ? WEXITSTATUS(status) : 0);
436 kill(wl->child, SIGTERM);
441 kill(wl->child, SIGTERM);
451 setup_tty(struct weston_launch *wl, const char *tty)
457 t = ttyname(STDIN_FILENO);
458 if (t && strcmp(t, tty) == 0)
459 wl->tty = STDIN_FILENO;
461 wl->tty = open(tty, O_RDWR | O_NOCTTY);
463 int tty0 = open("/dev/tty0", O_WRONLY | O_CLOEXEC);
467 error(1, errno, "could not open tty0");
469 if (ioctl(tty0, VT_OPENQRY, &wl->ttynr) < 0 || wl->ttynr == -1)
470 error(1, errno, "failed to find non-opened console");
472 snprintf(filename, sizeof filename, "/dev/tty%d", wl->ttynr);
473 wl->tty = open(filename, O_RDWR | O_NOCTTY);
478 error(1, errno, "failed to open tty");
481 if (fstat(wl->tty, &buf) < 0)
482 error(1, errno, "stat %s failed", tty);
484 if (major(buf.st_rdev) != TTY_MAJOR)
485 error(1, 0, "invalid tty device: %s", tty);
487 wl->ttynr = minor(buf.st_rdev);
494 help(const char *name)
496 fprintf(stderr, "Usage: %s [args...] [-- [weston args..]]\n", name);
497 fprintf(stderr, " -u, --user Start session as specified username\n");
498 fprintf(stderr, " -t, --tty Start session on alternative tty\n");
499 fprintf(stderr, " -v, --verbose Be verbose\n");
500 fprintf(stderr, " -s, --sleep Sleep specified amount of time before exec\n");
501 fprintf(stderr, " -h, --help Display this help message\n");
505 main(int argc, char *argv[])
507 struct weston_launch wl;
511 char *tty = NULL, *new_user = NULL;
513 struct option opts[] = {
514 { "user", required_argument, NULL, 'u' },
515 { "tty", required_argument, NULL, 't' },
516 { "verbose", no_argument, NULL, 'v' },
517 { "sleep", optional_argument, NULL, 's' },
518 { "help", no_argument, NULL, 'h' },
522 memset(&wl, 0, sizeof wl);
524 while ((c = getopt_long(argc, argv, "u:t:s::vh", opts, &i)) != -1) {
529 error(1, 0, "Permission denied. -u allowed for root only");
539 sleep_fork = atoi(optarg);
544 help("weston-launch");
549 child_argv = &argv[optind-1];
550 child_argv[0] = BINDIR "/weston";
553 wl.pw = getpwnam(new_user);
555 wl.pw = getpwuid(getuid());
557 error(1, errno, "failed to get username");
560 setenv("USER", wl.pw->pw_name, 1);
561 setenv("LOGNAME", wl.pw->pw_name, 1);
562 setenv("HOME", wl.pw->pw_dir, 1);
563 setenv("SHELL", wl.pw->pw_shell, 1);
565 if (!weston_launch_allowed(&wl))
566 error(1, 0, "Permission denied. You should either:\n"
567 #ifdef HAVE_SYSTEMD_LOGIN
568 " - run from an active and local (systemd) session.\n"
570 " - enable systemd session support for weston-launch.\n"
572 " - or add yourself to the 'weston-launch' group.");
574 if (setup_tty(&wl, tty) < 0)
577 if (setup_pam(&wl) < 0)
580 wl.epollfd = epoll_create1(EPOLL_CLOEXEC);
582 error(1, errno, "epoll create failed");
584 if (setup_launcher_socket(&wl) < 0)
587 if (setup_signals(&wl) < 0)
590 switch ((wl.child = fork())) {
592 error(1, errno, "fork failed");
596 printf("weston-launch: spawned weston with pid: %d\n", getpid());
597 if (wl.tty != STDIN_FILENO) {
599 error(1, errno, "setsid failed");
600 if (ioctl(wl.tty, TIOCSCTTY, 0) < 0)
601 error(1, errno, "TIOCSCTTY failed - tty is in use");
604 if (setgid(wl.pw->pw_gid) < 0 ||
605 setuid(wl.pw->pw_uid) < 0)
606 error(1, errno, "dropping privilidges failed");
610 printf("weston-launch: waiting %d seconds\n", sleep_fork);
614 env = pam_getenvlist(wl.ph);
616 for (i = 0; env[i]; ++i) {
617 if (putenv(env[i]) < 0)
618 error(0, 0, "putenv %s failed", env[i]);
623 if (wl.tty != STDIN_FILENO)
624 setenv_fd("WESTON_TTY_FD", wl.tty);
626 setenv_fd("WESTON_LAUNCHER_SOCK", wl.sock[1]);
630 execv(child_argv[0], child_argv);
631 error(1, errno, "exec failed");
635 if (wl.tty != STDIN_FILENO)
639 struct epoll_event ev;
642 n = epoll_wait(wl.epollfd, &ev, 1, -1);
644 error(0, errno, "epoll_wait failed");
648 if (ev.data.fd == wl.sock[0])
649 handle_socket_msg(&wl);
650 else if (ev.data.fd == wl.signalfd)