src/seat-unity.c

   1 /*
   2  * Copyright (C) 2012-2013 Robert Ancell.
   3  * Author: Robert Ancell <robert.ancell@canonical.com>
   4  *
   5  * This program is free software: you can redistribute it and/or modify it under
   6  * the terms of the GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option) any later
   8  * version. See http://www.gnu.org/copyleft/gpl.html the full text of the
   9  * license.
  10  */
  11
  12 #include <string.h>
  13 #include <fcntl.h>
  14 #include <errno.h>
  15 #include <glib/gstdio.h>
  16
  17 #include "seat-unity.h"
  18 #include "configuration.h"
  19 #include "x-server-local.h"
  20 #include "mir-server.h"
  21 #include "vt.h"
  22 #include "plymouth.h"
  23
  24 typedef enum
  25 {
  26    USC_MESSAGE_PING = 0,
  27    USC_MESSAGE_PONG = 1,
  28    USC_MESSAGE_READY = 2,
  29    USC_MESSAGE_SESSION_CONNECTED = 3,
  30    USC_MESSAGE_SET_ACTIVE_SESSION = 4
  31 } USCMessageID;
  32
  33 struct SeatUnityPrivate
  34 {
  35     /* VT we are running on */
  36     gint vt;
  37
  38     /* TRUE if waiting for X server to start before stopping Plymouth */
  39     gboolean stopping_plymouth;
  40
  41     /* File to log to */
  42     gchar *log_file;
  43
  44     /* Filename of Mir socket */
  45     gchar *mir_socket_filename;
  46
  47     /* Pipes to communicate with compositor */
  48     int to_compositor_pipe[2];
  49     int from_compositor_pipe[2];
  50
  51     /* IO channel listening on for messages from the compositor */
  52     GIOChannel *from_compositor_channel;
  53
  54     /* TRUE when the compositor indicates it is ready */
  55     gboolean compositor_ready;
  56
  57     /* Buffer reading from channel */
  58     guint8 *read_buffer;
  59     gsize read_buffer_length;
  60     gsize read_buffer_n_used;
  61
  62     /* Compositor process */
  63     Process *compositor_process;
  64
  65     /* Timeout when waiting for compositor to start */
  66     guint compositor_timeout;
  67
  68     /* Next Mir ID to use for a compositor client */
  69     gint next_id;
  70
  71     /* TRUE if using VT switching fallback */
  72     gboolean use_vt_switching;
  73
  74     /* The currently visible session */
  75     Session *active_session;
  76     DisplayServer *active_display_server;
  77 };
  78
  79 G_DEFINE_TYPE (SeatUnity, seat_unity, SEAT_TYPE);
  80
  81 static gboolean
  82 seat_unity_get_start_local_sessions (Seat *seat)
  83 {
  84     return !seat_get_string_property (seat, "xdmcp-manager");
  85 }
  86
  87 static void
  88 seat_unity_setup (Seat *seat)
  89 {
  90     seat_set_can_switch (seat, TRUE);
  91     SEAT_CLASS (seat_unity_parent_class)->setup (seat);
  92 }
  93
  94 static void
  95 compositor_stopped_cb (Process *process, SeatUnity *seat)
  96 {
  97     if (seat->priv->compositor_timeout != 0)
  98         g_source_remove (seat->priv->compositor_timeout);
  99     seat->priv->compositor_timeout = 0;
 100
 101     /* Finished with the VT */
 102     vt_unref (seat->priv->vt);
 103     seat->priv->vt = -1;
 104
 105     if (seat_get_is_stopping (SEAT (seat)))
 106     {
 107         SEAT_CLASS (seat_unity_parent_class)->stop (SEAT (seat));
 108         return;
 109     }
 110
 111     /* If stopped before it was ready, then revert to VT mode */
 112     if (!seat->priv->compositor_ready)
 113     {
 114         g_debug ("Compositor failed to start, switching to VT mode");
 115         seat->priv->use_vt_switching = TRUE;
 116         SEAT_CLASS (seat_unity_parent_class)->start (SEAT (seat));
 117         return;
 118     }
 119
 120     g_debug ("Stopping Unity seat, compositor terminated");
 121
 122     if (seat->priv->stopping_plymouth)
 123     {
 124         g_debug ("Stopping Plymouth, compositor failed to start");
 125         plymouth_quit (FALSE);
 126         seat->priv->stopping_plymouth = FALSE;
 127     }
 128
 129     seat_stop (SEAT (seat));
 130 }
 131
 132 static void
 133 compositor_run_cb (Process *process, SeatUnity *seat)
 134 {
 135     int fd;
 136
 137     /* Make input non-blocking */
 138     fd = open ("/dev/null", O_RDONLY);
 139     dup2 (fd, STDIN_FILENO);
 140     close (fd);
 141
 142     /* Redirect output to logfile */
 143     if (seat->priv->log_file)
 144     {
 145          int fd;
 146
 147          fd = g_open (seat->priv->log_file, O_WRONLY | O_CREAT | O_TRUNC, 0600);
 148          if (fd < 0)
 149              g_warning ("Failed to open log file %s: %s", seat->priv->log_file, g_strerror (errno));
 150          else
 151          {
 152              dup2 (fd, STDOUT_FILENO);
 153              dup2 (fd, STDERR_FILENO);
 154              close (fd);
 155          }
 156     }
 157
 158     if (seat->priv->stopping_plymouth)
 159     {
 160         seat->priv->stopping_plymouth = FALSE;
 161         plymouth_quit (TRUE);
 162     }
 163 }
 164
 165 static void
 166 write_message (SeatUnity *seat, guint16 id, const guint8 *payload, guint16 payload_length)
 167 {
 168     guint8 *data;
 169     gsize data_length = 4 + payload_length;
 170
 171     data = g_malloc (data_length);
 172     data[0] = id >> 8;
 173     data[1] = id & 0xFF;
 174     data[2] = payload_length >> 8;
 175     data[3] = payload_length & 0xFF;
 176     memcpy (data + 4, payload, payload_length);
 177
 178     errno = 0;
 179     if (write (seat->priv->to_compositor_pipe[1], data, data_length) != data_length)
 180         g_warning ("Failed to write to compositor: %s", strerror (errno));
 181 }
 182
 183 static gboolean
 184 read_cb (GIOChannel *source, GIOCondition condition, gpointer data)
 185 {
 186     SeatUnity *seat = data;
 187     gsize n_to_read = 0;
 188     guint16 id, payload_length;
 189     /*guint8 *payload;*/
 190
 191     if (condition == G_IO_HUP)
 192     {
 193         g_debug ("Compositor closed communication channel");
 194         return FALSE;
 195     }
 196
 197     /* Work out how much required for a message */
 198     if (seat->priv->read_buffer_n_used < 4)
 199         n_to_read = 4 - seat->priv->read_buffer_n_used;
 200     else
 201     {
 202         payload_length = seat->priv->read_buffer[2] << 8 | seat->priv->read_buffer[3];
 203         n_to_read = 4 + payload_length - seat->priv->read_buffer_n_used;
 204     }
 205
 206     /* Read from compositor */
 207     if (n_to_read > 0)
 208     {
 209         gsize n_total, n_read = 0;
 210         GIOStatus status;
 211         GError *error = NULL;
 212
 213         n_total = seat->priv->read_buffer_n_used + n_to_read;
 214         if (seat->priv->read_buffer_length < n_total)
 215             seat->priv->read_buffer = g_realloc (seat->priv->read_buffer, n_total);
 216
 217         status = g_io_channel_read_chars (source,
 218                                           (gchar *)seat->priv->read_buffer + seat->priv->read_buffer_n_used,
 219                                           n_to_read,
 220                                           &n_read,
 221                                           &error);
 222         if (error)
 223             g_warning ("Failed to read from compositor: %s", error->message);
 224         if (status != G_IO_STATUS_NORMAL)
 225             return TRUE;
 226         g_clear_error (&error);
 227         seat->priv->read_buffer_n_used += n_read;
 228     }
 229
 230     /* Read header */
 231     if (seat->priv->read_buffer_n_used < 4)
 232          return TRUE;
 233     id = seat->priv->read_buffer[0] << 8 | seat->priv->read_buffer[1];
 234     payload_length = seat->priv->read_buffer[2] << 8 | seat->priv->read_buffer[3];
 235
 236     /* Read payload */
 237     if (seat->priv->read_buffer_n_used < 4 + payload_length)
 238         return TRUE;
 239     /*payload = seat->priv->read_buffer + 4;*/
 240
 241     switch (id)
 242     {
 243     case USC_MESSAGE_PING:
 244         g_debug ("PING!");
 245         write_message (seat, USC_MESSAGE_PONG, NULL, 0);
 246         break;
 247     case USC_MESSAGE_PONG:
 248         g_debug ("PONG!");
 249         break;
 250     case USC_MESSAGE_READY:
 251         g_debug ("READY");
 252         if (!seat->priv->compositor_ready)
 253         {
 254             seat->priv->compositor_ready = TRUE;
 255             g_debug ("Compositor ready");
 256             g_source_remove (seat->priv->compositor_timeout);
 257             seat->priv->compositor_timeout = 0;
 258             SEAT_CLASS (seat_unity_parent_class)->start (SEAT (seat));
 259         }
 260         break;
 261     case USC_MESSAGE_SESSION_CONNECTED:
 262         g_debug ("SESSION CONNECTED");
 263         break;
 264     default:
 265         g_warning ("Ingoring unknown message %d with %d octets from system compositor", id, payload_length);
 266         break;
 267     }
 268
 269     /* Clear buffer */
 270     seat->priv->read_buffer_n_used = 0;
 271
 272     return TRUE;
 273 }
 274
 275 static gchar *
 276 get_absolute_command (const gchar *command)
 277 {
 278     gchar **tokens;
 279     gchar *absolute_binary, *absolute_command = NULL;
 280
 281     tokens = g_strsplit (command, " ", 2);
 282
 283     absolute_binary = g_find_program_in_path (tokens[0]);
 284     if (absolute_binary)
 285     {
 286         if (tokens[1])
 287             absolute_command = g_strjoin (" ", absolute_binary, tokens[1], NULL);
 288         else
 289             absolute_command = g_strdup (absolute_binary);
 290         g_free (absolute_binary);
 291     }
 292     else
 293         absolute_command = g_strdup (command);
 294
 295     g_strfreev (tokens);
 296
 297     return absolute_command;
 298 }
 299
 300 static gboolean
 301 compositor_timeout_cb (gpointer data)
 302 {
 303     SeatUnity *seat = data;
 304
 305     /* Stop the compositor - it is not working */
 306     process_stop (seat->priv->compositor_process);
 307
 308     return TRUE;
 309 }
 310
 311 static gboolean
 312 seat_unity_start (Seat *seat)
 313 {
 314     const gchar *compositor_command;
 315     gchar *command, *absolute_command, *dir;
 316     gboolean result;
 317     int timeout;
 318
 319     /* Replace Plymouth if it is running */
 320     if (plymouth_get_is_active () && plymouth_has_active_vt ())
 321     {
 322         gint active_vt = vt_get_active ();
 323         if (active_vt >= vt_get_min ())
 324         {
 325             g_debug ("Compositor will replace Plymouth");
 326             SEAT_UNITY (seat)->priv->stopping_plymouth = TRUE;
 327             SEAT_UNITY (seat)->priv->vt = active_vt;
 328             plymouth_deactivate ();
 329         }
 330         else
 331             g_debug ("Plymouth is running on VT %d, but this is less than the configured minimum of %d so not replacing it", active_vt, vt_get_min ());
 332     }
 333     if (SEAT_UNITY (seat)->priv->vt < 0)
 334         SEAT_UNITY (seat)->priv->vt = vt_get_unused ();
 335     if (SEAT_UNITY (seat)->priv->vt < 0)
 336     {
 337         g_debug ("Failed to get a VT to run on");
 338         return FALSE;
 339     }
 340     vt_ref (SEAT_UNITY (seat)->priv->vt);
 341
 342     /* Create pipes to talk to compositor */
 343     if (pipe (SEAT_UNITY (seat)->priv->to_compositor_pipe) < 0 || pipe (SEAT_UNITY (seat)->priv->from_compositor_pipe) < 0)
 344     {
 345         g_debug ("Failed to create compositor pipes: %s", g_strerror (errno));
 346         return FALSE;
 347     }
 348
 349     /* Don't allow the daemon end of the pipes to be accessed in the compositor */
 350     fcntl (SEAT_UNITY (seat)->priv->to_compositor_pipe[1], F_SETFD, FD_CLOEXEC);
 351     fcntl (SEAT_UNITY (seat)->priv->from_compositor_pipe[0], F_SETFD, FD_CLOEXEC);
 352
 353     /* Listen for messages from the compositor */
 354     SEAT_UNITY (seat)->priv->from_compositor_channel = g_io_channel_unix_new (SEAT_UNITY (seat)->priv->from_compositor_pipe[0]);
 355     g_io_add_watch (SEAT_UNITY (seat)->priv->from_compositor_channel, G_IO_IN | G_IO_HUP, read_cb, seat);
 356
 357     /* Setup logging */
 358     dir = config_get_string (config_get_instance (), "LightDM", "log-directory");
 359     SEAT_UNITY (seat)->priv->log_file = g_build_filename (dir, "unity-system-compositor.log", NULL);
 360     g_debug ("Logging to %s", SEAT_UNITY (seat)->priv->log_file);
 361     g_free (dir);
 362
 363     SEAT_UNITY (seat)->priv->mir_socket_filename = g_strdup ("/tmp/mir_socket"); // FIXME: Use this socket by default as XMir is hardcoded to this
 364     timeout = seat_get_integer_property (seat, "unity-compositor-timeout");
 365     compositor_command = seat_get_string_property (seat, "unity-compositor-command");
 366     command = g_strdup_printf ("%s --from-dm-fd %d --to-dm-fd %d --vt %d", compositor_command, SEAT_UNITY (seat)->priv->to_compositor_pipe[0], SEAT_UNITY (seat)->priv->from_compositor_pipe[1], SEAT_UNITY (seat)->priv->vt);
 367
 368     absolute_command = get_absolute_command (command);
 369     g_free (command);
 370
 371     /* Start the compositor */
 372     process_set_command (SEAT_UNITY (seat)->priv->compositor_process, absolute_command);
 373     g_free (absolute_command);
 374     g_signal_connect (SEAT_UNITY (seat)->priv->compositor_process, "stopped", G_CALLBACK (compositor_stopped_cb), seat);
 375     g_signal_connect (SEAT_UNITY (seat)->priv->compositor_process, "run", G_CALLBACK (compositor_run_cb), seat);
 376     result = process_start (SEAT_UNITY (seat)->priv->compositor_process, FALSE);
 377
 378     /* Close compostor ends of the pipes */
 379     close (SEAT_UNITY (seat)->priv->to_compositor_pipe[0]);
 380     SEAT_UNITY (seat)->priv->to_compositor_pipe[0] = 0;
 381     close (SEAT_UNITY (seat)->priv->from_compositor_pipe[1]);
 382     SEAT_UNITY (seat)->priv->from_compositor_pipe[1] = 0;
 383
 384     if (!result)
 385         return FALSE;
 386
 387     /* Connect to the compositor */
 388     timeout = seat_get_integer_property (seat, "unity-compositor-timeout");
 389     if (timeout <= 0)
 390         timeout = 60;
 391     g_debug ("Waiting for system compositor for %ds", timeout);
 392     SEAT_UNITY (seat)->priv->compositor_timeout = g_timeout_add (timeout * 1000, compositor_timeout_cb, seat);
 393
 394     return TRUE;
 395 }
 396
 397 static DisplayServer *
 398 create_x_server (Seat *seat)
 399 {
 400     XServerLocal *x_server;
 401     const gchar *command = NULL, *layout = NULL, *config_file = NULL, *xdmcp_manager = NULL, *key_name = NULL;
 402     gboolean allow_tcp;
 403     gint port = 0;
 404     gchar *id;
 405
 406     g_debug ("Starting X server on Unity compositor");
 407
 408     x_server = x_server_local_new ();
 409
 410     if (!SEAT_UNITY (seat)->priv->use_vt_switching)
 411     {
 412         id = g_strdup_printf ("%d", SEAT_UNITY (seat)->priv->next_id);
 413         SEAT_UNITY (seat)->priv->next_id++;
 414         x_server_local_set_mir_id (x_server, id);
 415         x_server_local_set_mir_socket (x_server, SEAT_UNITY (seat)->priv->mir_socket_filename);
 416         g_free (id);
 417     }
 418
 419     command = seat_get_string_property (seat, "xserver-command");
 420     if (command)
 421         x_server_local_set_command (x_server, command);
 422
 423     layout = seat_get_string_property (seat, "xserver-layout");
 424     if (layout)
 425         x_server_local_set_layout (x_server, layout);
 426
 427     config_file = seat_get_string_property (seat, "xserver-config");
 428     if (config_file)
 429         x_server_local_set_config (x_server, config_file);
 430
 431     allow_tcp = seat_get_boolean_property (seat, "xserver-allow-tcp");
 432     x_server_local_set_allow_tcp (x_server, allow_tcp);
 433
 434     xdmcp_manager = seat_get_string_property (seat, "xdmcp-manager");
 435     if (xdmcp_manager)
 436         x_server_local_set_xdmcp_server (x_server, xdmcp_manager);
 437
 438     port = seat_get_integer_property (seat, "xdmcp-port");
 439     if (port > 0)
 440         x_server_local_set_xdmcp_port (x_server, port);
 441
 442     key_name = seat_get_string_property (seat, "xdmcp-key");
 443     if (key_name)
 444     {
 445         gchar *dir, *path;
 446         GKeyFile *keys;
 447         gboolean result;
 448         GError *error = NULL;
 449
 450         dir = config_get_string (config_get_instance (), "LightDM", "config-directory");
 451         path = g_build_filename (dir, "keys.conf", NULL);
 452         g_free (dir);
 453
 454         keys = g_key_file_new ();
 455         result = g_key_file_load_from_file (keys, path, G_KEY_FILE_NONE, &error);
 456         if (error)
 457             g_debug ("Error getting key %s", error->message);
 458         g_clear_error (&error);
 459
 460         if (result)
 461         {
 462             gchar *key = NULL;
 463
 464             if (g_key_file_has_key (keys, "keyring", key_name, NULL))
 465                 key = g_key_file_get_string (keys, "keyring", key_name, NULL);
 466             else
 467                 g_debug ("Key %s not defined", key_name);
 468
 469             if (key)
 470                 x_server_local_set_xdmcp_key (x_server, key);
 471             g_free (key);
 472         }
 473
 474         g_free (path);
 475         g_key_file_free (keys);
 476     }
 477
 478     return DISPLAY_SERVER (x_server);
 479 }
 480
 481 static DisplayServer *
 482 seat_unity_create_display_server (Seat *seat, const gchar *session_type)
 483 {
 484     if (strcmp (session_type, "x") == 0)
 485         return create_x_server (seat);
 486     else if (strcmp (session_type, "mir") == 0)
 487         return DISPLAY_SERVER (mir_server_new ());
 488     else
 489     {
 490         g_warning ("Can't create unsupported display server '%s'", session_type);
 491         return NULL;
 492     }
 493 }
 494
 495 static Greeter *
 496 seat_unity_create_greeter_session (Seat *seat)
 497 {
 498     Greeter *greeter_session;
 499
 500     greeter_session = greeter_new ();
 501     session_set_env (SESSION (greeter_session), "XDG_SEAT", "seat0");
 502
 503     return greeter_session;
 504 }
 505
 506 static Session *
 507 seat_unity_create_session (Seat *seat)
 508 {
 509     Session *session;
 510
 511     session = session_new ();
 512     session_set_env (session, "XDG_SEAT", "seat0");
 513
 514     return session;
 515 }
 516
 517 static void
 518 seat_unity_set_active_session (Seat *seat, Session *session)
 519 {
 520     DisplayServer *display_server;
 521
 522     /* If no compositor, have to use VT switching */
 523     if (SEAT_UNITY (seat)->priv->use_vt_switching)
 524     {
 525         gint vt = display_server_get_vt (session_get_display_server (session));
 526         if (vt >= 0)
 527             vt_set_active (vt);
 528
 529         SEAT_CLASS (seat_unity_parent_class)->set_active_session (seat, session);
 530         return;
 531     }
 532
 533     if (session == SEAT_UNITY (seat)->priv->active_session)
 534         return;
 535     SEAT_UNITY (seat)->priv->active_session = g_object_ref (session);
 536
 537     display_server = session_get_display_server (session);
 538     if (SEAT_UNITY (seat)->priv->active_display_server != display_server)
 539     {
 540         const gchar *id;
 541
 542         SEAT_UNITY (seat)->priv->active_display_server = g_object_ref (display_server);
 543         id = x_server_local_get_mir_id (X_SERVER_LOCAL (display_server));
 544
 545         g_debug ("Switching to Mir session %s", id);
 546         write_message (SEAT_UNITY (seat), USC_MESSAGE_SET_ACTIVE_SESSION, (const guint8 *) id, strlen (id));
 547     }
 548
 549     SEAT_CLASS (seat_unity_parent_class)->set_active_session (seat, session);
 550 }
 551
 552 static Session *
 553 seat_unity_get_active_session (Seat *seat)
 554 {
 555     if (SEAT_UNITY (seat)->priv->use_vt_switching)
 556     {
 557         gint vt;
 558         GList *link;
 559         vt = vt_get_active ();
 560         if (vt < 0)
 561             return NULL;
 562
 563         for (link = seat_get_sessions (seat); link; link = link->next)
 564         {
 565             Session *session = link->data;
 566             if (display_server_get_vt (session_get_display_server (session)) == vt)
 567                 return session;
 568         }
 569
 570         return NULL;
 571     }
 572
 573     return SEAT_UNITY (seat)->priv->active_session;
 574 }
 575
 576 static void
 577 seat_unity_run_script (Seat *seat, DisplayServer *display_server, Process *script)
 578 {
 579     const gchar *path;
 580     XServerLocal *x_server;
 581
 582     x_server = X_SERVER_LOCAL (display_server);
 583     path = x_server_local_get_authority_file_path (x_server);
 584     process_set_env (script, "DISPLAY", x_server_get_address (X_SERVER (x_server)));
 585     process_set_env (script, "XAUTHORITY", path);
 586
 587     SEAT_CLASS (seat_unity_parent_class)->run_script (seat, display_server, script);
 588 }
 589
 590 static void
 591 seat_unity_stop (Seat *seat)
 592 {
 593     /* Stop the compositor first */
 594     if (process_get_is_running (SEAT_UNITY (seat)->priv->compositor_process))
 595     {
 596         process_stop (SEAT_UNITY (seat)->priv->compositor_process);
 597         return;
 598     }
 599
 600     SEAT_CLASS (seat_unity_parent_class)->stop (seat);
 601 }
 602
 603 static void
 604 seat_unity_init (SeatUnity *seat)
 605 {
 606     seat->priv = G_TYPE_INSTANCE_GET_PRIVATE (seat, SEAT_UNITY_TYPE, SeatUnityPrivate);
 607     seat->priv->vt = -1;
 608     seat->priv->compositor_process = process_new ();
 609 }
 610
 611 static void
 612 seat_unity_finalize (GObject *object)
 613 {
 614     SeatUnity *seat = SEAT_UNITY (object);
 615
 616     if (seat->priv->vt >= 0)
 617         vt_unref (seat->priv->vt);
 618     g_free (seat->priv->log_file);
 619     g_free (seat->priv->mir_socket_filename);
 620     close (seat->priv->to_compositor_pipe[0]);
 621     close (seat->priv->to_compositor_pipe[1]);
 622     close (seat->priv->from_compositor_pipe[0]);
 623     close (seat->priv->from_compositor_pipe[1]);
 624     g_io_channel_unref (seat->priv->from_compositor_channel);
 625     g_free (seat->priv->read_buffer);
 626     g_object_unref (seat->priv->compositor_process);
 627     if (seat->priv->active_session)
 628         g_object_unref (seat->priv->active_session);
 629     if (seat->priv->active_display_server)
 630         g_object_unref (seat->priv->active_display_server);
 631
 632     G_OBJECT_CLASS (seat_unity_parent_class)->finalize (object);
 633 }
 634
 635 static void
 636 seat_unity_class_init (SeatUnityClass *klass)
 637 {
 638     GObjectClass *object_class = G_OBJECT_CLASS (klass);
 639     SeatClass *seat_class = SEAT_CLASS (klass);
 640
 641     object_class->finalize = seat_unity_finalize;
 642     seat_class->get_start_local_sessions = seat_unity_get_start_local_sessions;
 643     seat_class->setup = seat_unity_setup;
 644     seat_class->start = seat_unity_start;
 645     seat_class->create_display_server = seat_unity_create_display_server;
 646     seat_class->create_greeter_session = seat_unity_create_greeter_session;
 647     seat_class->create_session = seat_unity_create_session;
 648     seat_class->set_active_session = seat_unity_set_active_session;
 649     seat_class->get_active_session = seat_unity_get_active_session;
 650     seat_class->run_script = seat_unity_run_script;
 651     seat_class->stop = seat_unity_stop;
 652
 653     g_type_class_add_private (klass, sizeof (SeatUnityPrivate));
 654 }