daemon: add wrapper for launching wayland session

This wrapper makes sure the wayland session is registered with
the display manager, and that the wayland session gets a dbus-daemon
that's automatically cleaned up when the session goes away.

https://bugzilla.gnome.org/show_bug.cgi?id=744764

1 files changed, 451 insertions, 0 deletions

diff --git a/daemon/gdm-wayland-session.c b/daemon/gdm-wayland-session.c
new file mode 100644
index 00000000..16a70b6e
--- /dev/null
+++ b/daemon/gdm-wayland-session.c
@@ -0,0 +1,451 @@
+/* -*- 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>
+
+#define BUS_ADDRESS_FILENO (STDERR_FILENO + 1)
+#define DBUS_DAEMON BINDIR "/dbus-daemon"
+
+typedef struct
+{
+        GdmSettings  *settings;
+        GCancellable *cancellable;
+        GSubprocess  *bus_subprocess;
+        char         *bus_address;
+
+        GSubprocess  *session_subprocess;
+        char         *session_command;
+        int           session_exit_status;
+
+        GMainLoop    *main_loop;
+
+        guint32       debug_enabled : 1;
+} State;
+
+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);
+        }
+
+out:
+        g_clear_object (&state->bus_subprocess);
+        g_main_loop_quit (state->main_loop);
+}
+
+static gboolean
+spawn_bus (State        *state,
+           GCancellable *cancellable)
+{
+        GPtrArray           *arguments;
+        GSubprocessLauncher *launcher;
+        GSubprocess         *subprocess;
+        GInputStream        *input_stream;
+        GDataInputStream    *data_stream;
+        GError              *error = NULL;
+        char                *bus_address_fd_string;
+        char                *bus_address;
+        gsize                bus_address_size;
+
+        gboolean  is_running = FALSE;
+        int       ret;
+        int       pipe_fds[2];
+
+        g_debug ("Running session message bus");
+
+        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 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);
+
+        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);
+
+        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 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);
+        }
+
+out:
+        g_clear_object (&state->session_subprocess);
+        g_main_loop_quit (state->main_loop);
+}
+
+static gboolean
+spawn_session (State        *state,
+               GCancellable *cancellable)
+{
+        GSubprocessLauncher *launcher;
+        GSubprocess         *subprocess = NULL;
+        GError              *error = NULL;
+        gboolean             is_running = FALSE;
+        int                  ret;
+        char               **argv;
+
+        g_debug ("Running wayland session");
+
+        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;
+        }
+
+        launcher = g_subprocess_launcher_new (G_SUBPROCESS_FLAGS_NONE);
+        g_subprocess_launcher_setenv (launcher, "DBUS_SESSION_BUS_ADDRESS", state->bus_address, TRUE);
+        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);
+        }
+}
+
+static void
+wait_on_subprocesses (State *state)
+{
+        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)
+{
+        GdmDBusManager  *manager;
+        GError          *error = NULL;
+        gboolean         registered = FALSE;
+        GVariantBuilder  details;
+
+        manager = 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",
+                                                           cancellable,
+                                                           &error);
+
+        if (!manager) {
+                g_debug ("could not contact display manager: %s", error->message);
+                g_error_free (error);
+                goto out;
+        }
+
+        g_variant_builder_init (&details, G_VARIANT_TYPE ("a{ss}"));
+        g_variant_builder_add (&details, "{ss}", "session-type", "wayland");
+
+        registered = gdm_dbus_manager_call_register_display_sync (manager,
+                                                                  g_variant_builder_end (&details),
+                                                                  cancellable,
+                                                                  &error);
+        if (error != NULL) {
+                g_debug ("Could not register display: %s", error->message);
+                g_error_free (error);
+        }
+
+out:
+        g_clear_object (&manager);
+        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->session_subprocess);
+        g_clear_pointer (&state->main_loop, g_main_loop_unref);
+        *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;
+}
+
+int
+main (int    argc,
+      char **argv)
+{
+        State           *state;
+        GOptionContext  *context;
+        static char    **args = NULL;
+        gboolean         debug = FALSE;
+        gboolean         ret;
+        int              exit_status = EX_OK;
+        static GOptionEntry entries []   = {
+                { 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 Wayland 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-wayland-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");
+                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_bus (state, state->cancellable);
+
+        if (!ret) {
+                g_printerr ("Unable to run session message bus");
+                exit_status = EX_SOFTWARE;
+                goto out;
+        }
+
+        ret = spawn_session (state, state->cancellable);
+
+        if (!ret) {
+                g_printerr ("Unable to run session");
+                exit_status = EX_SOFTWARE;
+                goto out;
+        }
+
+        ret = register_display (state, state->cancellable);
+
+        if (!ret) {
+                g_printerr ("Unable to register display with display manager");
+                exit_status = EX_SOFTWARE;
+                goto out;
+        }
+
+        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:
+        signal_subprocesses (state);
+        wait_on_subprocesses (state);
+        clear_state (&state);
+
+        return exit_status;
+}