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);
87 groups = malloc(n * sizeof(gid_t));
91 if (getgroups(n, groups) < 0) {
99 weston_launch_allowed(struct weston_launch *wl)
104 #ifdef HAVE_SYSTEMD_LOGIN
105 char *session, *seat;
112 gr = getgrnam("weston-launch");
114 groups = read_groups();
116 for (i = 0; groups[i]; ++i) {
117 if (groups[i] == gr->gr_gid) {
126 #ifdef HAVE_SYSTEMD_LOGIN
127 err = sd_pid_get_session(getpid(), &session);
128 if (err == 0 && session) {
129 if (sd_session_is_active(session) &&
130 sd_session_get_seat(session, &seat) == 0) {
143 pam_conversation_fn(int msg_count,
144 const struct pam_message **messages,
145 struct pam_response **responses,
152 setup_pam(struct weston_launch *wl)
156 wl->pc.conv = pam_conversation_fn;
157 wl->pc.appdata_ptr = wl;
159 err = pam_start("login", wl->pw->pw_name, &wl->pc, &wl->ph);
160 err = pam_set_item(wl->ph, PAM_TTY, ttyname(wl->tty));
161 if (err != PAM_SUCCESS) {
162 fprintf(stderr, "failed to set PAM_TTY item: %d: %s\n",
163 err, pam_strerror(wl->ph, err));
167 err = pam_open_session(wl->ph, 0);
168 if (err != PAM_SUCCESS) {
169 fprintf(stderr, "failed to open pam session: %d: %s\n",
170 err, pam_strerror(wl->ph, err));
178 setup_launcher_socket(struct weston_launch *wl)
180 struct epoll_event ev;
182 if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, wl->sock) < 0)
183 error(1, errno, "socketpair failed");
185 fcntl(wl->sock[0], F_SETFD, O_CLOEXEC);
187 memset(&ev, 0, sizeof ev);
189 ev.data.fd = wl->sock[0];
190 if (epoll_ctl(wl->epollfd, EPOLL_CTL_ADD, ev.data.fd, &ev) < 0)
197 setup_signals(struct weston_launch *wl)
201 struct epoll_event ev;
203 memset(&sa, 0, sizeof sa);
204 sa.sa_handler = SIG_DFL;
205 sa.sa_flags = SA_NOCLDSTOP | SA_RESTART;
206 assert(sigaction(SIGCHLD, &sa, NULL) == 0);
208 assert(sigemptyset(&mask) == 0);
209 sigaddset(&mask, SIGCHLD);
210 sigaddset(&mask, SIGINT);
211 sigaddset(&mask, SIGTERM);
212 assert(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
214 wl->signalfd = signalfd(-1, &mask, SFD_NONBLOCK | SFD_CLOEXEC);
215 if (wl->signalfd < 0)
218 memset(&ev, 0, sizeof ev);
220 ev.data.fd = wl->signalfd;
221 if (epoll_ctl(wl->epollfd, EPOLL_CTL_ADD, ev.data.fd, &ev) < 0)
228 setenv_fd(const char *env, int fd)
232 snprintf(buf, sizeof buf, "%d", fd);
237 handle_setmaster(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
240 struct cmsghdr *cmsg;
241 struct weston_launcher_set_master *message;
242 union cmsg_data *data;
244 if (len != sizeof(*message)) {
245 error(0, 0, "missing value in setmaster request");
249 message = msg->msg_iov->iov_base;
251 cmsg = CMSG_FIRSTHDR(msg);
253 cmsg->cmsg_level != SOL_SOCKET ||
254 cmsg->cmsg_type != SCM_RIGHTS) {
255 error(0, 0, "invalid control message");
259 data = (union cmsg_data *) CMSG_DATA(cmsg);
260 if (data->fd == -1) {
261 error(0, 0, "missing drm fd in socket request");
265 if (message->set_master)
266 ret = drmSetMaster(data->fd);
268 ret = drmDropMaster(data->fd);
273 len = send(wl->sock[0], &ret, sizeof ret, 0);
274 } while (len < 0 && errno == EINTR);
282 handle_open(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
284 int fd = -1, ret = -1;
285 char control[CMSG_SPACE(sizeof(fd))];
286 struct cmsghdr *cmsg;
290 struct weston_launcher_open *message;
291 union cmsg_data *data;
293 message = msg->msg_iov->iov_base;
294 if ((size_t)len < sizeof(*message))
297 /* Ensure path is null-terminated */
298 ((char *) message)[len-1] = '\0';
300 if (stat(message->path, &s) < 0)
303 fd = open(message->path, message->flags);
307 if (major(s.st_rdev) != INPUT_MAJOR) {
314 memset(&nmsg, 0, sizeof nmsg);
318 nmsg.msg_control = control;
319 nmsg.msg_controllen = sizeof control;
320 cmsg = CMSG_FIRSTHDR(&nmsg);
321 cmsg->cmsg_level = SOL_SOCKET;
322 cmsg->cmsg_type = SCM_RIGHTS;
323 cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
324 data = (union cmsg_data *) CMSG_DATA(cmsg);
326 nmsg.msg_controllen = cmsg->cmsg_len;
330 iov.iov_len = sizeof ret;
333 fprintf(stderr, "weston-launch: opened %s: ret: %d, fd: %d\n",
334 message->path, ret, fd);
336 len = sendmsg(wl->sock[0], &nmsg, 0);
337 } while (len < 0 && errno == EINTR);
346 handle_socket_msg(struct weston_launch *wl)
348 char control[CMSG_SPACE(sizeof(int))];
354 struct weston_launcher_message *message;
356 memset(&msg, 0, sizeof(msg));
358 iov.iov_len = sizeof buf;
361 msg.msg_control = control;
362 msg.msg_controllen = sizeof control;
365 len = recvmsg(wl->sock[0], &msg, 0);
366 } while (len < 0 && errno == EINTR);
371 message = (void *) buf;
372 switch (message->opcode) {
373 case WESTON_LAUNCHER_OPEN:
374 ret = handle_open(wl, &msg, len);
376 case WESTON_LAUNCHER_DRM_SET_MASTER:
377 ret = handle_setmaster(wl, &msg, len);
385 quit(struct weston_launch *wl, int status)
393 err = pam_close_session(wl->ph, 0);
395 fprintf(stderr, "pam_close_session failed: %d: %s\n",
396 err, pam_strerror(wl->ph, err));
397 pam_end(wl->ph, err);
403 handle_signal(struct weston_launch *wl)
405 struct signalfd_siginfo sig;
408 if (read(wl->signalfd, &sig, sizeof sig) != sizeof sig) {
409 error(0, errno, "reading signalfd failed");
413 switch (sig.ssi_signo) {
415 pid = waitpid(-1, &status, 0);
416 if (pid == wl->child) {
418 quit(wl, WIFEXITED(status) ? WEXITSTATUS(status) : 0);
423 kill(wl->child, SIGTERM);
428 kill(wl->child, SIGTERM);
438 setup_tty(struct weston_launch *wl, const char *tty)
444 t = ttyname(STDIN_FILENO);
445 if (t && strcmp(t, tty) == 0)
446 wl->tty = STDIN_FILENO;
448 wl->tty = open(tty, O_RDWR | O_NOCTTY);
450 int tty0 = open("/dev/tty0", O_WRONLY | O_CLOEXEC);
454 error(1, errno, "could not open tty0");
456 if (ioctl(tty0, VT_OPENQRY, &wl->ttynr) < 0 || wl->ttynr == -1)
457 error(1, errno, "failed to find non-opened console");
459 snprintf(filename, sizeof filename, "/dev/tty%d", wl->ttynr);
460 wl->tty = open(filename, O_RDWR | O_NOCTTY);
465 error(1, errno, "failed to open tty");
468 if (fstat(wl->tty, &buf) < 0)
469 error(1, errno, "stat %s failed", tty);
471 if (major(buf.st_rdev) != TTY_MAJOR)
472 error(1, 0, "invalid tty device: %s", tty);
474 wl->ttynr = minor(buf.st_rdev);
481 help(const char *name)
483 fprintf(stderr, "Usage: %s [args...] [-- [weston args..]]\n", name);
484 fprintf(stderr, " -u, --user Start session as specified username\n");
485 fprintf(stderr, " -t, --tty Start session on alternative tty\n");
486 fprintf(stderr, " -v, --verbose Be verbose\n");
487 fprintf(stderr, " -s, --sleep Sleep specified amount of time before exec\n");
488 fprintf(stderr, " -h, --help Display this help message\n");
492 main(int argc, char *argv[])
494 struct weston_launch wl;
498 char *tty = NULL, *new_user = NULL;
500 struct option opts[] = {
501 { "user", required_argument, NULL, 'u' },
502 { "tty", required_argument, NULL, 't' },
503 { "verbose", no_argument, NULL, 'v' },
504 { "sleep", optional_argument, NULL, 's' },
505 { "help", no_argument, NULL, 'h' },
509 memset(&wl, 0, sizeof wl);
511 while ((c = getopt_long(argc, argv, "u:t:s::vh", opts, &i)) != -1) {
516 error(1, 0, "Permission denied. -u allowed for root only");
526 sleep_fork = atoi(optarg);
536 child_argv = &argv[optind-1];
537 child_argv[0] = BINDIR "/weston";
540 wl.pw = getpwnam(new_user);
542 wl.pw = getpwuid(getuid());
544 error(1, errno, "failed to get username");
546 if (!weston_launch_allowed(&wl))
547 error(1, 0, "Permission denied. You should either:\n"
548 #ifdef HAVE_SYSTEMD_LOGIN
549 " - run from an active and local (systemd) session.\n"
551 " - enable systemd session support for weston-launch.\n"
553 " - or add yourself to the 'weston-launch' group.");
555 if (setup_tty(&wl, tty) < 0)
558 if (setup_pam(&wl) < 0)
561 wl.epollfd = epoll_create1(EPOLL_CLOEXEC);
563 error(1, errno, "epoll create failed");
565 if (setup_launcher_socket(&wl) < 0)
568 if (setup_signals(&wl) < 0)
571 switch ((wl.child = fork())) {
573 error(1, errno, "fork failed");
577 printf("weston-launch: spawned weston with pid: %d\n", getpid());
578 if (wl.tty != STDIN_FILENO) {
580 error(1, errno, "setsid failed");
581 if (ioctl(wl.tty, TIOCSCTTY, 0) < 0)
582 error(1, errno, "TIOCSCTTY failed - tty is in use");
585 if (setgid(wl.pw->pw_gid) < 0 ||
586 setuid(wl.pw->pw_uid) < 0)
587 error(1, errno, "dropping privilidges failed");
591 printf("weston-launch: waiting %d seconds\n", sleep_fork);
596 setenv("USER", wl.pw->pw_name, 1);
597 setenv("LOGNAME", wl.pw->pw_name, 1);
598 setenv("HOME", wl.pw->pw_dir, 1);
599 setenv("SHELL", wl.pw->pw_shell, 1);
601 env = pam_getenvlist(wl.ph);
603 for (i = 0; env[i]; ++i) {
604 if (putenv(env[i]) < 0)
605 error(0, 0, "putenv %s failed", env[i]);
610 if (wl.tty != STDIN_FILENO)
611 setenv_fd("WESTON_TTY_FD", wl.tty);
613 setenv_fd("WESTON_LAUNCHER_SOCK", wl.sock[1]);
617 execv(child_argv[0], child_argv);
618 error(1, errno, "exec failed");
622 if (wl.tty != STDIN_FILENO)
626 struct epoll_event ev;
629 n = epoll_wait(wl.epollfd, &ev, 1, -1);
631 error(0, errno, "epoll_wait failed");
635 if (ev.data.fd == wl.sock[0])
636 handle_socket_msg(&wl);
637 else if (ev.data.fd == wl.signalfd)