wayland: import weston-launch setuid launcher

To run mutter as a display server, one needs to acquire and
release the DRM master, which is only possible for root, so
we take advantage of weston-launch, a small setuid helper binary
written for the weston project. We import our own slightly
modified copy of it, because weston-launch only launches weston,
for security reasons.

https://bugzilla.gnome.org/show_bug.cgi?id=705861

4 files changed, 767 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 427cf721c..7072ea119 100644
--- a/configure.ac
+++ b/configure.ac
@@ -139,6 +139,7 @@ AM_GLIB_GNU_GETTEXT
 ## here we get the flags we'll actually use
 # GRegex requires Glib-2.14.0
 PKG_CHECK_MODULES(ALL, glib-2.0 >= 2.14.0)
+PKG_CHECK_MODULES(MUTTER_LAUNCH, libdrm libsystemd-login)
 
 # Unconditionally use this dir to avoid a circular dep with gnomecc
 GNOME_KEYBINDINGS_KEYSDIR="${datadir}/gnome-control-center/keybindings"
diff --git a/src/Makefile.am b/src/Makefile.am
index 7fca4f23d..f747bf722 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -247,6 +247,17 @@ bin_PROGRAMS=mutter-wayland
 mutter_wayland_SOURCES = core/mutter.c
 mutter_wayland_LDADD = $(MUTTER_LIBS) libmutter-wayland.la
 
+bin_PROGRAMS+=mutter-launch
+
+mutter_launch_SOURCES = wayland/weston-launch.c wayland/weston-launch.h
+
+mutter_launch_CFLAGS = $(MUTTER_LAUNCH_CFLAGS)
+mutter_launch_LDFLAGS = $(MUTTER_LAUNCH_LIBS) -lpam
+
+install-exec-hook:
+	-chown root $(DESTDIR)$(bindir)/mutter-launch
+	-chmod u+s $(DESTDIR)$(bindir)/mutter-launch
+
 if HAVE_INTROSPECTION
 include $(INTROSPECTION_MAKEFILE)
 
diff --git a/src/wayland/weston-launch.c b/src/wayland/weston-launch.c
new file mode 100644
index 000000000..ead260c68
--- /dev/null
+++ b/src/wayland/weston-launch.c
@@ -0,0 +1,709 @@
+/*
+ * 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 <pwd.h>
+#include <grp.h>
+#include <security/pam_appl.h>
+
+#include <xf86drm.h>
+
+#ifdef HAVE_SYSTEMD_LOGIN
+#include <systemd/sd-login.h>
+#endif
+
+#include "weston-launch.h"
+
+#define MAX_ARGV_SIZE 256
+
+struct weston_launch {
+	struct pam_conv pc;
+	pam_handle_t *ph;
+	int tty;
+	int ttynr;
+	int sock[2];
+	struct passwd *pw;
+
+	int signalfd;
+
+	pid_t child;
+	int verbose;
+	char *new_user;
+};
+
+union cmsg_data { unsigned char b[4]; int fd; };
+
+static gid_t *
+read_groups(void)
+{
+	int n;
+	gid_t *groups;
+	
+	n = getgroups(0, NULL);
+
+	if (n < 0) {
+		fprintf(stderr, "Unable to retrieve groups: %m\n");
+		return NULL;
+	}
+
+	groups = malloc(n * sizeof(gid_t));
+	if (!groups)
+		return NULL;
+
+	if (getgroups(n, groups) < 0) {
+		fprintf(stderr, "Unable to retrieve groups: %m\n");
+		free(groups);
+		return NULL;
+	}
+	return groups;
+}
+
+static int
+weston_launch_allowed(struct weston_launch *wl)
+{
+	struct group *gr;
+	gid_t *groups;
+	int i;
+#ifdef HAVE_SYSTEMD_LOGIN
+	char *session, *seat;
+	int err;
+#endif
+
+	if (getuid() == 0)
+		return 1;
+
+	gr = getgrnam("weston-launch");
+	if (gr) {
+		groups = read_groups();
+		if (groups) {
+			for (i = 0; groups[i]; ++i) {
+				if (groups[i] == gr->gr_gid) {
+					free(groups);
+					return 1;
+				}
+			}
+			free(groups);
+		}
+	}
+
+#ifdef HAVE_SYSTEMD_LOGIN
+	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);
+	}
+#endif
+	
+	return 0;
+}
+
+static int
+pam_conversation_fn(int msg_count,
+		    const struct pam_message **messages,
+		    struct pam_response **responses,
+		    void *user_data)
+{
+	return PAM_SUCCESS;
+}
+
+static int
+setup_pam(struct weston_launch *wl)
+{
+	int err;
+
+	wl->pc.conv = pam_conversation_fn;
+	wl->pc.appdata_ptr = wl;
+
+	err = pam_start("login", wl->pw->pw_name, &wl->pc, &wl->ph);
+	if (err != PAM_SUCCESS) {
+		fprintf(stderr, "failed to start pam transaction: %d: %s\n",
+			err, pam_strerror(wl->ph, err));
+		return -1;
+	}
+
+	err = pam_set_item(wl->ph, PAM_TTY, ttyname(wl->tty));
+	if (err != PAM_SUCCESS) {
+		fprintf(stderr, "failed to set PAM_TTY item: %d: %s\n",
+			err, pam_strerror(wl->ph, err));
+		return -1;
+	}
+
+	err = pam_open_session(wl->ph, 0);
+	if (err != PAM_SUCCESS) {
+		fprintf(stderr, "failed to open pam session: %d: %s\n",
+			err, pam_strerror(wl->ph, err));
+		return -1;
+	}
+
+	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);
+	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_setmaster(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
+{
+	int ret = -1;
+	struct cmsghdr *cmsg;
+	struct weston_launcher_set_master *message;
+	union cmsg_data *data;
+
+	if (len != sizeof(*message)) {
+		error(0, 0, "missing value in setmaster request");
+		goto out;
+	}
+
+	message = msg->msg_iov->iov_base;
+
+	cmsg = CMSG_FIRSTHDR(msg);
+	if (!cmsg ||
+	    cmsg->cmsg_level != SOL_SOCKET ||
+	    cmsg->cmsg_type != SCM_RIGHTS) {
+		error(0, 0, "invalid control message");
+		goto out;
+	}
+
+	data = (union cmsg_data *) CMSG_DATA(cmsg);
+	if (data->fd == -1) {
+		error(0, 0, "missing drm fd in socket request");
+		goto out;
+	}
+
+	if (message->set_master)
+		ret = drmSetMaster(data->fd);
+	else
+		ret = drmDropMaster(data->fd);
+
+	close(data->fd);
+
+	if (wl->verbose)
+		fprintf(stderr, "weston-launch: %sMaster, ret: %d, fd: %d\n",
+			message->set_master ? "set" : "drop", ret, data->fd);
+
+out:
+	do {
+		len = send(wl->sock[0], &ret, sizeof ret, 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)
+{
+	int fd = -1, ret = -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;
+
+	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)
+		goto err0;
+
+	fd = open(message->path, message->flags);
+	if (fd < 0) {
+		fprintf(stderr, "Error opening device %s: %m\n",
+			message->path);
+		goto err0;
+	}
+
+	if (major(s.st_rdev) != INPUT_MAJOR) {
+		close(fd);
+		fd = -1;
+		fprintf(stderr, "Device %s is not an input device\n",
+			message->path);
+		goto err0;
+	}
+
+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;
+		ret = 0;
+	}
+	iov.iov_base = &ret;
+	iov.iov_len = sizeof ret;
+
+	if (wl->verbose)
+		fprintf(stderr, "weston-launch: opened %s: ret: %d, fd: %d\n",
+			message->path, 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_DRM_SET_MASTER:
+		ret = handle_setmaster(wl, &msg, len);
+		break;
+	}
+
+	return ret;
+}
+
+static void
+quit(struct weston_launch *wl, int status)
+{
+	int err;
+
+	close(wl->signalfd);
+	close(wl->sock[0]);
+
+	if (wl->new_user) {
+		err = pam_close_session(wl->ph, 0);
+		if (err)
+			fprintf(stderr, "pam_close_session failed: %d: %s\n",
+				err, pam_strerror(wl->ph, err));
+		pam_end(wl->ph, err);
+	}
+
+	exit(status);
+}
+
+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;
+	default:
+		return -1;
+	}
+
+	return 0;
+}
+
+static int
+setup_tty(struct weston_launch *wl, const char *tty)
+{
+	struct stat buf;
+	char *t;
+
+	if (!wl->new_user) {
+		wl->tty = STDIN_FILENO;
+	} else if (tty) {
+		t = ttyname(STDIN_FILENO);
+		if (t && strcmp(t, tty) == 0)
+			wl->tty = STDIN_FILENO;
+		else
+			wl->tty = open(tty, O_RDWR | O_NOCTTY);
+	} else {
+		int tty0 = open("/dev/tty0", O_WRONLY | O_CLOEXEC);
+		char filename[16];
+
+		if (tty0 < 0)
+			error(1, errno, "could not open tty0");
+
+		if (ioctl(tty0, VT_OPENQRY, &wl->ttynr) < 0 || wl->ttynr == -1)
+			error(1, errno, "failed to find non-opened console"); 
+
+		snprintf(filename, sizeof filename, "/dev/tty%d", wl->ttynr);
+		wl->tty = open(filename, O_RDWR | O_NOCTTY);
+		close(tty0);
+	}
+
+	if (wl->tty < 0)
+		error(1, errno, "failed to open tty");
+
+	if (tty) {
+		if (fstat(wl->tty, &buf) < 0)
+			error(1, errno, "stat %s failed", tty);
+
+		if (major(buf.st_rdev) != TTY_MAJOR)
+			error(1, 0, "invalid tty device: %s", tty);
+
+		wl->ttynr = minor(buf.st_rdev);
+	}
+
+	return 0;
+}
+
+static void
+setup_session(struct weston_launch *wl)
+{
+	char **env;
+	char *term;
+	int i;
+
+	if (wl->tty != STDIN_FILENO) {
+		if (setsid() < 0)
+			error(1, errno, "setsid failed");
+		if (ioctl(wl->tty, TIOCSCTTY, 0) < 0)
+			error(1, errno, "TIOCSCTTY failed - tty is in use");
+	}
+
+	term = getenv("TERM");
+	clearenv();
+	if (term)
+		setenv("TERM", term, 1);
+	setenv("USER", wl->pw->pw_name, 1);
+	setenv("LOGNAME", wl->pw->pw_name, 1);
+	setenv("HOME", wl->pw->pw_dir, 1);
+	setenv("SHELL", wl->pw->pw_shell, 1);
+
+	env = pam_getenvlist(wl->ph);
+	if (env) {
+		for (i = 0; env[i]; ++i) {
+			if (putenv(env[i]) < 0)
+				error(0, 0, "putenv %s failed", env[i]);
+		}
+		free(env);
+	}
+}
+
+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());
+	if (wl->new_user)
+		setup_session(wl);
+
+	drop_privileges(wl);
+
+	if (wl->tty != STDIN_FILENO)
+		setenv_fd("WESTON_TTY_FD", wl->tty);
+
+	setenv_fd("WESTON_LAUNCHER_SOCK", wl->sock[1]);
+
+	unsetenv("DISPLAY");
+
+	/* Do not give our signal mask to the new process. */
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGTERM);
+	sigaddset(&mask, SIGCHLD);
+	sigaddset(&mask, SIGINT);
+	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, "  -t, --tty       Start session on alternative tty\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;
+	char *tty = NULL;
+	struct option opts[] = {
+		{ "user",    required_argument, NULL, 'u' },
+		{ "tty",     required_argument, NULL, 't' },
+		{ "verbose", no_argument,       NULL, 'v' },
+		{ "help",    no_argument,       NULL, 'h' },
+		{ 0,         0,                 NULL,  0  }
+	};	
+
+	memset(&wl, 0, sizeof wl);
+
+	while ((c = getopt_long(argc, argv, "u:t::vh", opts, &i)) != -1) {
+		switch (c) {
+		case 'u':
+			wl.new_user = optarg;
+			if (getuid() != 0)
+				error(1, 0, "Permission denied. -u allowed for root only");
+			break;
+		case 't':
+			tty = optarg;
+			break;
+		case 'v':
+			wl.verbose = 1;
+			break;
+		case 'h':
+			help("weston-launch");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	if ((argc - optind) > (MAX_ARGV_SIZE - 6))
+		error(1, E2BIG, "Too many arguments to pass to weston");
+
+	if (strcmp (argv[optind], "mutter-wayland") &&
+	    strcmp (argv[optind], "gnome-shell-wayland"))
+	  error(1, 0, "mutter-launch can only be used to launch mutter or gnome-shell");
+
+	if (wl.new_user)
+		wl.pw = getpwnam(wl.new_user);
+	else
+		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 should either:\n"
+#ifdef HAVE_SYSTEMD_LOGIN
+		      " - run from an active and local (systemd) session.\n"
+#else
+		      " - enable systemd session support for weston-launch.\n"
+#endif
+		      " - or add yourself to the 'weston-launch' group.");
+
+	if (setup_tty(&wl, tty) < 0)
+		exit(EXIT_FAILURE);
+
+	if (wl.new_user && setup_pam(&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]);
+	if (wl.tty != STDIN_FILENO)
+		close(wl.tty);
+
+	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;
+}
diff --git a/src/wayland/weston-launch.h b/src/wayland/weston-launch.h
new file mode 100644
index 000000000..5be013efc
--- /dev/null
+++ b/src/wayland/weston-launch.h
@@ -0,0 +1,46 @@
+/*
+ * 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.
+ */
+
+#ifndef _WESTON_LAUNCH_H_
+#define _WESTON_LAUNCH_H_
+
+enum weston_launcher_opcode {
+	WESTON_LAUNCHER_OPEN,
+	WESTON_LAUNCHER_DRM_SET_MASTER
+};
+
+struct weston_launcher_message {
+	int opcode;
+};
+
+struct weston_launcher_open {
+	struct weston_launcher_message header;
+	int flags;
+	char path[0];
+};
+
+struct weston_launcher_set_master {
+	struct weston_launcher_message header;
+	int set_master;
+};
+
+#endif