Adding upstream version 43.0.upstream/43.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 997 insertions, 0 deletions

diff --git a/daemon/gdm-x-session.c b/daemon/gdm-x-session.c
new file mode 100644
index 0000000..0b07ab5
--- /dev/null
+++ b/daemon/gdm-x-session.c
@@ -0,0 +1,997 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2015 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+#include "config.h"
+
+#include <locale.h>
+#include <sysexits.h>
+
+#include "gdm-common.h"
+#include "gdm-settings-direct.h"
+#include "gdm-settings-keys.h"
+#include "gdm-log.h"
+
+#include "gdm-manager-glue.h"
+
+#include <glib/gi18n.h>
+#include <glib/gstdio.h>
+#include <glib-unix.h>
+#include <glib.h>
+#include <gio/gunixinputstream.h>
+#include <glib-unix.h>
+#include <X11/Xauth.h>
+
+#define DISPLAY_FILENO (STDERR_FILENO + 1)
+#define BUS_ADDRESS_FILENO (DISPLAY_FILENO + 1)
+
+typedef struct
+{
+        GdmSettings  *settings;
+        GCancellable *cancellable;
+
+        GSubprocess  *x_subprocess;
+        char         *auth_file;
+        char         *display_name;
+
+        GSubprocess     *bus_subprocess;
+        GDBusConnection *bus_connection;
+        GdmDBusManager  *display_manager_proxy;
+        char            *bus_address;
+
+        char           **environment;
+
+        GSubprocess  *session_subprocess;
+        char         *session_command;
+        int           session_exit_status;
+
+        guint         register_session_id;
+
+        GMainLoop    *main_loop;
+
+        guint32       debug_enabled : 1;
+} State;
+
+static FILE *
+create_auth_file (char **filename)
+{
+        char *auth_dir = NULL;
+        char *auth_file = NULL;
+        int fd;
+        FILE *fp = NULL;
+
+        auth_dir = g_build_filename (g_get_user_runtime_dir (),
+                                     "gdm",
+                                     NULL);
+
+        g_mkdir_with_parents (auth_dir, 0711);
+        auth_file = g_build_filename (auth_dir, "Xauthority", NULL);
+        g_clear_pointer (&auth_dir, g_free);
+
+        fd = g_open (auth_file, O_RDWR | O_CREAT | O_TRUNC, 0700);
+
+        if (fd < 0) {
+                g_debug ("could not open %s to store auth cookie: %m",
+                         auth_file);
+                g_clear_pointer (&auth_file, g_free);
+                goto out;
+        }
+
+        fp = fdopen (fd, "w+");
+
+        if (fp == NULL) {
+                g_debug ("could not set up stream for auth cookie file: %m");
+                g_clear_pointer (&auth_file, g_free);
+                close (fd);
+                goto out;
+        }
+
+        *filename = auth_file;
+out:
+        return fp;
+}
+
+static char *
+prepare_auth_file (void)
+{
+        FILE     *fp = NULL;
+        char     *filename = NULL;
+        GError   *error = NULL;
+        gboolean  prepared = FALSE;
+        Xauth     auth_entry = { 0 };
+        char      localhost[HOST_NAME_MAX + 1] = "";
+
+        g_debug ("Preparing auth file for X server");
+
+        fp = create_auth_file (&filename);
+
+        if (fp == NULL) {
+                return NULL;
+        }
+
+        if (gethostname (localhost, HOST_NAME_MAX) < 0) {
+                strncpy (localhost, "localhost", sizeof (localhost) - 1);
+        }
+
+        auth_entry.family = FamilyLocal;
+        auth_entry.address = localhost;
+        auth_entry.address_length = strlen (auth_entry.address);
+        auth_entry.name = "MIT-MAGIC-COOKIE-1";
+        auth_entry.name_length = strlen (auth_entry.name);
+
+        auth_entry.data_length = 16;
+        auth_entry.data = gdm_generate_random_bytes (auth_entry.data_length, &error);
+
+        if (error != NULL) {
+                goto out;
+        }
+
+        if (!XauWriteAuth (fp, &auth_entry) || fflush (fp) == EOF) {
+                goto out;
+        }
+
+        auth_entry.family = FamilyWild;
+        if (!XauWriteAuth (fp, &auth_entry) || fflush (fp) == EOF) {
+                goto out;
+        }
+
+        prepared = TRUE;
+
+out:
+        g_clear_pointer (&auth_entry.data, g_free);
+        g_clear_pointer (&fp, fclose);
+
+        if (!prepared) {
+                g_clear_pointer (&filename, g_free);
+        }
+
+        return filename;
+}
+
+static void
+on_x_server_finished (GSubprocess  *subprocess,
+                      GAsyncResult *result,
+                      State        *state)
+{
+        gboolean cancelled;
+
+        cancelled = !g_subprocess_wait_finish (subprocess, result, NULL);
+
+        if (cancelled) {
+                goto out;
+        }
+
+        if (g_subprocess_get_if_exited (subprocess)) {
+                int exit_status;
+
+                exit_status = g_subprocess_get_exit_status (subprocess);
+
+                g_debug ("X server exited with status %d", exit_status);
+        } else {
+                int signal_number;
+
+                signal_number = g_subprocess_get_term_sig (subprocess);
+                g_debug ("X server was killed with status %d", signal_number);
+        }
+
+        g_clear_object (&state->x_subprocess);
+out:
+        g_main_loop_quit (state->main_loop);
+}
+
+static gboolean
+spawn_x_server (State        *state,
+                gboolean      allow_remote_connections,
+                GCancellable *cancellable)
+{
+        GPtrArray           *arguments = NULL;
+        GSubprocessLauncher *launcher = NULL;
+        GSubprocess         *subprocess = NULL;
+        GInputStream        *input_stream = NULL;
+        GDataInputStream    *data_stream = NULL;
+        GError              *error = NULL;
+
+        char     *auth_file;
+        gboolean  is_running = FALSE;
+        int       ret;
+        int       pipe_fds[2];
+        char     *display_fd_string = NULL;
+        char     *vt_string = NULL;
+        char     *display_number;
+        gsize     display_number_size;
+
+        auth_file = prepare_auth_file ();
+
+        g_debug ("Running X server");
+
+        ret = g_unix_open_pipe (pipe_fds, FD_CLOEXEC, &error);
+
+        if (!ret) {
+                g_debug ("could not open pipe: %s", error->message);
+                goto out;
+        }
+
+        arguments = g_ptr_array_new ();
+        launcher = g_subprocess_launcher_new (G_SUBPROCESS_FLAGS_STDIN_INHERIT);
+        g_subprocess_launcher_setenv (launcher, "XORG_RUN_AS_USER_OK", "1", TRUE);
+        g_subprocess_launcher_take_fd (launcher, pipe_fds[1], DISPLAY_FILENO);
+
+        if (g_getenv ("XDG_VTNR") != NULL) {
+                int vt;
+
+                vt = atoi (g_getenv ("XDG_VTNR"));
+
+                if (vt > 0 && vt < 64) {
+                        vt_string = g_strdup_printf ("vt%d", vt);
+                }
+        }
+
+        display_fd_string = g_strdup_printf ("%d", DISPLAY_FILENO);
+
+        g_ptr_array_add (arguments, X_SERVER);
+
+        if (vt_string != NULL) {
+                g_ptr_array_add (arguments, vt_string);
+        }
+
+        g_ptr_array_add (arguments, "-displayfd");
+        g_ptr_array_add (arguments, display_fd_string);
+
+        g_ptr_array_add (arguments, "-auth");
+        g_ptr_array_add (arguments, auth_file);
+
+        /* If we were compiled with Xserver >= 1.17 we need to specify
+         * '-listen tcp' as the X server doesn't listen on tcp sockets
+         * by default anymore. In older versions we need to pass
+         * -nolisten tcp to disable listening on tcp sockets.
+         */
+        if (!allow_remote_connections) {
+                g_ptr_array_add (arguments, "-nolisten");
+                g_ptr_array_add (arguments, "tcp");
+        }
+
+#ifdef HAVE_XSERVER_WITH_LISTEN
+        if (allow_remote_connections) {
+                g_ptr_array_add (arguments, "-listen");
+                g_ptr_array_add (arguments, "tcp");
+        }
+#endif
+
+        g_ptr_array_add (arguments, "-background");
+        g_ptr_array_add (arguments, "none");
+
+        g_ptr_array_add (arguments, "-noreset");
+        g_ptr_array_add (arguments, "-keeptty");
+        g_ptr_array_add (arguments, "-novtswitch");
+
+        g_ptr_array_add (arguments, "-verbose");
+        if (state->debug_enabled) {
+                g_ptr_array_add (arguments, "7");
+        } else {
+                g_ptr_array_add (arguments, "3");
+        }
+
+        if (state->debug_enabled) {
+                g_ptr_array_add (arguments, "-core");
+        }
+        g_ptr_array_add (arguments, NULL);
+
+        subprocess = g_subprocess_launcher_spawnv (launcher,
+                                                   (const char * const *) arguments->pdata,
+                                                   &error);
+        g_free (display_fd_string);
+        g_clear_object (&launcher);
+        g_ptr_array_free (arguments, TRUE);
+
+        if (subprocess == NULL) {
+                g_debug ("could not start X server: %s", error->message);
+                goto out;
+        }
+
+        input_stream = g_unix_input_stream_new (pipe_fds[0], TRUE);
+        data_stream = g_data_input_stream_new (input_stream);
+        g_clear_object (&input_stream);
+
+        display_number = g_data_input_stream_read_line (data_stream,
+                                                        &display_number_size,
+                                                        cancellable,
+                                                        &error);
+
+        if (error != NULL) {
+                g_debug ("could not read display string from X server: %s", error->message);
+                goto out;
+        }
+
+        if (display_number == NULL) {
+                g_debug ("X server did not write display string");
+                goto out;
+        }
+
+        state->display_name = g_strdup_printf (":%s", display_number);
+        g_clear_pointer (&display_number, g_free);
+
+        state->auth_file = g_strdup (auth_file);
+        state->x_subprocess = g_object_ref (subprocess);
+
+        g_subprocess_wait_async (state->x_subprocess,
+                                 cancellable,
+                                 (GAsyncReadyCallback)
+                                 on_x_server_finished,
+                                 state);
+
+        is_running = TRUE;
+out:
+        g_clear_pointer (&auth_file, g_free);
+        g_clear_object (&data_stream);
+        g_clear_object (&subprocess);
+        g_clear_object (&launcher);
+        g_clear_error (&error);
+
+        return is_running;
+}
+
+static void
+on_bus_finished (GSubprocess  *subprocess,
+                 GAsyncResult *result,
+                 State        *state)
+{
+        gboolean cancelled;
+
+        cancelled = !g_subprocess_wait_finish (subprocess, result, NULL);
+
+        if (cancelled) {
+                goto out;
+        }
+
+        if (g_subprocess_get_if_exited (subprocess)) {
+                int exit_status;
+
+                exit_status = g_subprocess_get_exit_status (subprocess);
+
+                g_debug ("message bus exited with status %d", exit_status);
+        } else {
+                int signal_number;
+
+                signal_number = g_subprocess_get_term_sig (subprocess);
+                g_debug ("message bus was killed with status %d", signal_number);
+        }
+
+        g_clear_object (&state->bus_subprocess);
+out:
+        g_main_loop_quit (state->main_loop);
+}
+
+static gboolean
+update_bus_environment (State        *state,
+                        GCancellable *cancellable)
+{
+        GVariantBuilder      builder;
+        GVariant            *reply = NULL;
+        GError              *error = NULL;
+        gboolean             environment_updated = FALSE;
+
+        g_variant_builder_init (&builder, G_VARIANT_TYPE ("a{ss}"));
+        g_variant_builder_add (&builder, "{ss}", "DISPLAY", state->display_name);
+        g_variant_builder_add (&builder, "{ss}", "XAUTHORITY", state->auth_file);
+
+        reply = g_dbus_connection_call_sync (state->bus_connection,
+                                             "org.freedesktop.DBus",
+                                             "/org/freedesktop/DBus",
+                                             "org.freedesktop.DBus",
+                                             "UpdateActivationEnvironment",
+                                             g_variant_new ("(@a{ss})",
+                                                            g_variant_builder_end (&builder)),
+                                             NULL,
+                                             G_DBUS_CALL_FLAGS_NONE,
+                                             -1, cancellable, &error);
+
+        if (reply == NULL) {
+                g_debug ("could not update activation environment: %s", error->message);
+                goto out;
+        }
+
+        g_variant_unref (reply);
+
+        environment_updated = TRUE;
+
+out:
+        g_clear_error (&error);
+
+        return environment_updated;
+}
+
+static gboolean
+spawn_bus (State        *state,
+           GCancellable *cancellable)
+{
+        GDBusConnection     *bus_connection = NULL;
+        GPtrArray           *arguments = NULL;
+        GSubprocessLauncher *launcher = NULL;
+        GSubprocess         *subprocess = NULL;
+        GInputStream        *input_stream = NULL;
+        GDataInputStream    *data_stream = NULL;
+        GError              *error = NULL;
+        char                *bus_address_fd_string;
+        char                *bus_address = NULL;
+        gsize                bus_address_size;
+
+        gboolean  is_running = FALSE;
+        int       ret;
+        int       pipe_fds[2];
+
+        g_debug ("Running session message bus");
+
+        bus_connection = g_bus_get_sync (G_BUS_TYPE_SESSION,
+                                         cancellable,
+                                         NULL);
+
+        if (bus_connection != NULL) {
+                g_debug ("session message bus already running, not starting another one");
+                state->bus_connection = bus_connection;
+                return TRUE;
+        }
+
+        ret = g_unix_open_pipe (pipe_fds, FD_CLOEXEC, &error);
+
+        if (!ret) {
+                g_debug ("could not open pipe: %s", error->message);
+                goto out;
+        }
+
+        arguments = g_ptr_array_new ();
+        launcher = g_subprocess_launcher_new (G_SUBPROCESS_FLAGS_NONE);
+
+        g_subprocess_launcher_take_fd (launcher, pipe_fds[1], BUS_ADDRESS_FILENO);
+
+        bus_address_fd_string = g_strdup_printf ("%d", BUS_ADDRESS_FILENO);
+
+        g_ptr_array_add (arguments, "dbus-daemon");
+
+        g_ptr_array_add (arguments, "--print-address");
+        g_ptr_array_add (arguments, bus_address_fd_string);
+        g_ptr_array_add (arguments, "--session");
+        g_ptr_array_add (arguments, NULL);
+
+        subprocess = g_subprocess_launcher_spawnv (launcher,
+                                                   (const char * const *) arguments->pdata,
+                                                   &error);
+        g_free (bus_address_fd_string);
+        g_clear_object (&launcher);
+        g_ptr_array_free (arguments, TRUE);
+
+        if (subprocess == NULL) {
+                g_debug ("could not start dbus-daemon: %s", error->message);
+                goto out;
+        }
+
+        input_stream = g_unix_input_stream_new (pipe_fds[0], TRUE);
+        data_stream = g_data_input_stream_new (input_stream);
+        g_clear_object (&input_stream);
+
+        bus_address = g_data_input_stream_read_line (data_stream,
+                                                     &bus_address_size,
+                                                     cancellable,
+                                                     &error);
+
+        if (error != NULL) {
+                g_debug ("could not read address from session message bus: %s", error->message);
+                goto out;
+        }
+
+        if (bus_address == NULL) {
+                g_debug ("session message bus did not write address");
+                goto out;
+        }
+
+        state->bus_address = bus_address;
+
+        state->bus_subprocess = g_object_ref (subprocess);
+
+        g_subprocess_wait_async (state->bus_subprocess,
+                                 cancellable,
+                                 (GAsyncReadyCallback)
+                                 on_bus_finished,
+                                 state);
+
+
+        bus_connection = g_dbus_connection_new_for_address_sync (state->bus_address,
+                                                                 G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT |
+                                                                 G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION,
+                                                                 NULL,
+                                                                 cancellable,
+                                                                 &error);
+
+        if (bus_connection == NULL) {
+                g_debug ("could not open connection to session bus: %s",
+                         error->message);
+                goto out;
+        }
+
+        state->bus_connection = bus_connection;
+
+        is_running = TRUE;
+out:
+        g_clear_object (&data_stream);
+        g_clear_object (&subprocess);
+        g_clear_object (&launcher);
+        g_clear_error (&error);
+
+        return is_running;
+}
+
+static gboolean
+import_environment (State        *state,
+                    GCancellable *cancellable)
+{
+        g_autoptr(GVariant) reply = NULL;
+        g_autoptr(GVariant) environment_variant = NULL;
+        g_autoptr(GError)   error = NULL;
+
+        reply = g_dbus_connection_call_sync (state->bus_connection,
+                                             "org.freedesktop.systemd1",
+                                             "/org/freedesktop/systemd1",
+                                             "org.freedesktop.DBus.Properties",
+                                             "Get",
+                                             g_variant_new ("(ss)",
+                                                            "org.freedesktop.systemd1.Manager",
+                                                            "Environment"),
+                                             NULL,
+                                             G_DBUS_CALL_FLAGS_NONE,
+                                             -1, cancellable, &error);
+
+        if (reply == NULL) {
+                g_debug ("could not fetch environment: %s", error->message);
+                return FALSE;
+        }
+
+        g_variant_get (reply, "(v)", &environment_variant);
+
+        state->environment = g_variant_dup_strv (environment_variant, NULL);
+
+        return TRUE;
+}
+
+static void
+on_session_finished (GSubprocess  *subprocess,
+                     GAsyncResult *result,
+                     State        *state)
+{
+        gboolean cancelled;
+
+        cancelled = !g_subprocess_wait_finish (subprocess, result, NULL);
+
+        if (cancelled) {
+                goto out;
+        }
+
+        if (g_subprocess_get_if_exited (subprocess)) {
+                int exit_status;
+
+                exit_status = g_subprocess_get_exit_status (subprocess);
+
+                g_debug ("session exited with status %d", exit_status);
+
+                state->session_exit_status = exit_status;
+        } else {
+                int signal_number;
+
+                signal_number = g_subprocess_get_term_sig (subprocess);
+                g_debug ("session was killed with status %d", signal_number);
+        }
+
+        g_clear_object (&state->session_subprocess);
+out:
+        g_main_loop_quit (state->main_loop);
+}
+
+static gboolean
+spawn_session (State        *state,
+               gboolean      run_script,
+               GCancellable *cancellable)
+{
+        GSubprocessLauncher *launcher = NULL;
+        GSubprocess         *subprocess = NULL;
+        GError              *error = NULL;
+        gboolean             is_running = FALSE;
+        const char          *vt;
+        static const char   *session_variables[] = { "DISPLAY",
+                                                     "XAUTHORITY",
+                                                     "WAYLAND_DISPLAY",
+                                                     "WAYLAND_SOCKET",
+                                                     "GNOME_SHELL_SESSION_MODE",
+                                                     NULL };
+        /* The environment variables listed below are those we have set (or
+         * received from our own execution environment) only as a fallback to
+         * make things work, as opposed to a information directly pertaining to
+         * the session about to be started. Variables listed here will not
+         * overwrite the existing environment (possibly) imported from the
+         * systemd --user instance.
+         * As an example: We need a PATH for some of the launched subprocesses
+         * to work, but if the user (or the distributor) has customized the PATH
+         * via one of systemds user-environment-generators, that version should
+         * be preferred. */
+        static const char  *fallback_variables[] = { "PATH", NULL };
+
+        g_debug ("Running X session");
+
+        launcher = g_subprocess_launcher_new (G_SUBPROCESS_FLAGS_NONE);
+
+        if (state->environment != NULL) {
+                size_t i;
+
+                for (i = 0; state->environment[i] != NULL; i++) {
+                        g_auto(GStrv) environment_entry = NULL;
+
+                        if (state->environment[i][0] == '\0') {
+                                continue;
+                        }
+
+                        environment_entry = g_strsplit (state->environment[i], "=", 2);
+
+                        if (environment_entry[0] == NULL || environment_entry[1] == NULL) {
+                                continue;
+                        }
+
+                        /* Merge the environment block imported from systemd --user with the
+                         * environment we have set for ourselves (and thus pass on to the
+                         * launcher process). Variables we have set have precedence, as to not
+                         * import stale data from prior user sessions, with the exception of
+                         * those listed in fallback_variables. See the comment there for more
+                         * explanations. */
+                        g_subprocess_launcher_setenv (launcher,
+                                                      environment_entry[0],
+                                                      environment_entry[1],
+                                                      g_strv_contains (fallback_variables, environment_entry[0]));
+                }
+
+                /* Don't allow session specific environment variables from earlier sessions to
+                 * leak through */
+                for (i = 0; session_variables[i] != NULL; i++) {
+                        if (g_getenv (session_variables[i]) == NULL) {
+                                g_subprocess_launcher_unsetenv (launcher, session_variables[i]);
+                        }
+                }
+        }
+
+        g_subprocess_launcher_setenv (launcher, "DISPLAY", state->display_name, TRUE);
+        g_subprocess_launcher_setenv (launcher, "XAUTHORITY", state->auth_file, TRUE);
+
+        if (state->bus_address != NULL) {
+                g_subprocess_launcher_setenv (launcher, "DBUS_SESSION_BUS_ADDRESS", state->bus_address, TRUE);
+        }
+
+        vt = g_getenv ("XDG_VTNR");
+
+        if (vt != NULL) {
+                g_subprocess_launcher_setenv (launcher, "WINDOWPATH", vt, TRUE);
+        }
+
+        if (run_script) {
+                subprocess = g_subprocess_launcher_spawn (launcher,
+                                                          &error,
+                                                          GDMCONFDIR "/Xsession",
+                                                          state->session_command,
+                                                          NULL);
+        } else {
+                int ret;
+                char **argv;
+
+                ret = g_shell_parse_argv (state->session_command,
+                                          NULL,
+                                          &argv,
+                                          &error);
+
+                if (!ret) {
+                        g_debug ("could not parse session arguments: %s", error->message);
+                        goto out;
+                }
+                subprocess = g_subprocess_launcher_spawnv (launcher,
+                                                           (const char * const *) argv,
+                                                           &error);
+                g_strfreev (argv);
+        }
+
+        if (subprocess == NULL) {
+                g_debug ("could not start session: %s", error->message);
+                goto out;
+        }
+
+        state->session_subprocess = g_object_ref (subprocess);
+
+        g_subprocess_wait_async (state->session_subprocess,
+                                 cancellable,
+                                 (GAsyncReadyCallback)
+                                 on_session_finished,
+                                 state);
+
+        is_running = TRUE;
+out:
+        g_clear_object (&subprocess);
+        return is_running;
+}
+
+static void
+signal_subprocesses (State *state)
+{
+        if (state->session_subprocess != NULL) {
+                g_subprocess_send_signal (state->session_subprocess, SIGTERM);
+        }
+
+        if (state->bus_subprocess != NULL) {
+                g_subprocess_send_signal (state->bus_subprocess, SIGTERM);
+        }
+
+        if (state->x_subprocess != NULL) {
+                g_subprocess_send_signal (state->x_subprocess, SIGTERM);
+        }
+}
+
+static void
+wait_on_subprocesses (State *state)
+{
+        if (state->x_subprocess != NULL) {
+                g_subprocess_wait (state->x_subprocess, NULL, NULL);
+        }
+
+        if (state->bus_subprocess != NULL) {
+                g_subprocess_wait (state->bus_subprocess, NULL, NULL);
+        }
+
+        if (state->session_subprocess != NULL) {
+                g_subprocess_wait (state->session_subprocess, NULL, NULL);
+        }
+}
+
+static gboolean
+register_display (State        *state,
+                  GCancellable *cancellable)
+{
+        GError          *error = NULL;
+        gboolean         registered = FALSE;
+        GVariantBuilder  details;
+
+        g_variant_builder_init (&details, G_VARIANT_TYPE ("a{ss}"));
+        g_variant_builder_add (&details, "{ss}", "session-type", "x11");
+        g_variant_builder_add (&details, "{ss}", "x11-display-name", state->display_name);
+
+        registered = gdm_dbus_manager_call_register_display_sync (state->display_manager_proxy,
+                                                                  g_variant_builder_end (&details),
+                                                                  cancellable,
+                                                                  &error);
+        if (error != NULL) {
+                g_debug ("Could not register display: %s", error->message);
+                g_error_free (error);
+        }
+
+        return registered;
+}
+
+static void
+init_state (State **state)
+{
+        static State state_allocation;
+
+        *state = &state_allocation;
+}
+
+static void
+clear_state (State **out_state)
+{
+        State *state = *out_state;
+
+        g_clear_object (&state->cancellable);
+        g_clear_object (&state->bus_connection);
+        g_clear_object (&state->session_subprocess);
+        g_clear_object (&state->x_subprocess);
+        g_clear_pointer (&state->environment, g_strfreev);
+        g_clear_pointer (&state->auth_file, g_free);
+        g_clear_pointer (&state->display_name, g_free);
+        g_clear_pointer (&state->main_loop, g_main_loop_unref);
+        g_clear_handle_id (&state->register_session_id, g_source_remove);
+        *out_state = NULL;
+}
+
+static gboolean
+on_sigterm (State *state)
+{
+        g_cancellable_cancel (state->cancellable);
+
+        if (g_main_loop_is_running (state->main_loop)) {
+                g_main_loop_quit (state->main_loop);
+        }
+
+        return G_SOURCE_CONTINUE;
+}
+
+static gboolean
+register_session_timeout_cb (gpointer user_data)
+{
+        State *state;
+        GError *error = NULL;
+
+        state = (State *) user_data;
+
+        gdm_dbus_manager_call_register_session_sync (state->display_manager_proxy,
+                                                     g_variant_new ("a{sv}", NULL),
+                                                     state->cancellable,
+                                                     &error);
+
+        if (error != NULL) {
+                g_warning ("Could not register session: %s", error->message);
+                g_error_free (error);
+        }
+
+        return G_SOURCE_REMOVE;
+}
+
+static gboolean
+connect_to_display_manager (State *state)
+{
+        g_autoptr (GError) error = NULL;
+
+        state->display_manager_proxy = gdm_dbus_manager_proxy_new_for_bus_sync (
+                G_BUS_TYPE_SYSTEM,
+                G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES | G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS,
+                "org.gnome.DisplayManager",
+                "/org/gnome/DisplayManager/Manager",
+                state->cancellable,
+                &error);
+
+        if (state->display_manager_proxy == NULL) {
+                g_printerr ("gdm-x-session: could not contact display manager: %s\n",
+                            error->message);
+                return FALSE;
+        }
+
+        return TRUE;
+}
+
+int
+main (int    argc,
+      char **argv)
+{
+        State           *state = NULL;
+        GOptionContext  *context = NULL;
+        static char    **args = NULL;
+        static gboolean  run_script = FALSE;
+        static gboolean  allow_remote_connections = FALSE;
+        gboolean         debug = FALSE;
+        gboolean         ret;
+        int              exit_status = EX_OK;
+        static gboolean  register_session = FALSE;
+
+        static GOptionEntry entries []   = {
+                { "run-script", 'r', 0, G_OPTION_ARG_NONE, &run_script, N_("Run program through /etc/gdm/Xsession wrapper script"), NULL },
+                { "allow-remote-connections", 'a', 0, G_OPTION_ARG_NONE, &allow_remote_connections, N_("Listen on TCP socket"), NULL },
+                { "register-session", 0, 0, G_OPTION_ARG_NONE, &register_session, "Register session after a delay", NULL },
+                { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_STRING_ARRAY, &args, "", "" },
+                { NULL }
+        };
+
+        bindtextdomain (GETTEXT_PACKAGE, GNOMELOCALEDIR);
+        textdomain (GETTEXT_PACKAGE);
+        setlocale (LC_ALL, "");
+
+        gdm_log_init ();
+
+        context = g_option_context_new (_("GNOME Display Manager X Session Launcher"));
+        g_option_context_add_main_entries (context, entries, NULL);
+
+        g_option_context_parse (context, &argc, &argv, NULL);
+        g_option_context_free (context);
+
+        if (args == NULL || args[0] == NULL || args[1] != NULL) {
+                g_warning ("gdm-x-session takes one argument (the session)");
+                exit_status = EX_USAGE;
+                goto out;
+        }
+
+        init_state (&state);
+
+        state->session_command = args[0];
+
+        state->settings = gdm_settings_new ();
+        ret = gdm_settings_direct_init (state->settings, DATADIR "/gdm/gdm.schemas", "/");
+
+        if (!ret) {
+                g_printerr ("Unable to initialize settings\n");
+                exit_status = EX_DATAERR;
+                goto out;
+        }
+
+        gdm_settings_direct_get_boolean (GDM_KEY_DEBUG, &debug);
+        state->debug_enabled = debug;
+
+        gdm_log_set_debug (debug);
+
+        state->main_loop = g_main_loop_new (NULL, FALSE);
+        state->cancellable = g_cancellable_new ();
+
+        g_unix_signal_add (SIGTERM, (GSourceFunc) on_sigterm, state);
+
+        ret = spawn_x_server (state, allow_remote_connections, state->cancellable);
+
+        if (!ret) {
+                g_printerr ("Unable to run X server\n");
+                exit_status = EX_SOFTWARE;
+                goto out;
+        }
+
+        ret = spawn_bus (state, state->cancellable);
+
+        if (!ret) {
+                g_printerr ("Unable to run session message bus\n");
+                exit_status = EX_SOFTWARE;
+                goto out;
+        }
+
+        import_environment (state, state->cancellable);
+
+        ret = update_bus_environment (state, state->cancellable);
+
+        if (!ret) {
+                g_printerr ("Unable to update bus environment\n");
+                exit_status = EX_SOFTWARE;
+                goto out;
+        }
+
+        if (!connect_to_display_manager (state))
+                goto out;
+
+        ret = register_display (state, state->cancellable);
+
+        if (!ret) {
+                g_printerr ("Unable to register display with display manager\n");
+                exit_status = EX_SOFTWARE;
+                goto out;
+        }
+
+        ret = spawn_session (state, run_script, state->cancellable);
+
+        if (!ret) {
+                g_printerr ("Unable to run session\n");
+                exit_status = EX_SOFTWARE;
+                goto out;
+        }
+
+        if (register_session) {
+                g_debug ("gdm-x-session: Will register session in %d seconds", REGISTER_SESSION_TIMEOUT);
+                state->register_session_id = g_timeout_add_seconds (REGISTER_SESSION_TIMEOUT,
+                                                                    register_session_timeout_cb,
+                                                                    state);
+        } else {
+                g_debug ("gdm-x-session: Session will register itself");
+        }
+
+        g_main_loop_run (state->main_loop);
+
+        /* Only use exit status of session if we're here because it exit */
+
+        if (state->session_subprocess == NULL) {
+                exit_status = state->session_exit_status;
+        }
+
+out:
+        if (state != NULL) {
+                signal_subprocesses (state);
+                wait_on_subprocesses (state);
+                clear_state (&state);
+        }
+
+        return exit_status;
+}