bus/at-spi-bus-launcher.c

   1 /* -*- mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
   2  *
   3  * at-spi-bus-launcher: Manage the a11y bus as a child process
   4  *
   5  * Copyright 2011 Red Hat, Inc.
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Library General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Library General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Library General Public
  18  * License along with this library; if not, write to the
  19  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20  * Boston, MA 02111-1307, USA.
  21  */
  22
  23 #include "config.h"
  24
  25 #include <unistd.h>
  26 #include <string.h>
  27 #include <signal.h>
  28 #include <sys/wait.h>
  29 #include <errno.h>
  30 #include <stdio.h>
  31
  32 #include <gio/gio.h>
  33 #ifdef HAVE_X11
  34 #include <X11/Xlib.h>
  35 #include <X11/Xatom.h>
  36 #endif
  37
  38 #define APP_CONTROL_OPERATION_SCREEN_READ "http://tizen.org/appcontrol/operation/read_screen"
  39 #include <appsvc.h>
  40 #include <vconf.h>
  41 #include <dlog.h>
  42 #include <aul.h>
  43
  44 typedef enum {
  45   A11Y_BUS_STATE_IDLE = 0,
  46   A11Y_BUS_STATE_READING_ADDRESS,
  47   A11Y_BUS_STATE_RUNNING,
  48   A11Y_BUS_STATE_ERROR
  49 } A11yBusState;
  50
  51 typedef struct {
  52   GMainLoop *loop;
  53   gboolean launch_immediately;
  54   gboolean a11y_enabled;
  55   gboolean screen_reader_enabled;
  56   GDBusConnection *session_bus;
  57   GSettings *a11y_schema;
  58   GSettings *interface_schema;
  59
  60   gboolean screen_reader_needed;
  61   int pid;
  62
  63   A11yBusState state;
  64
  65   /* -1 == error, 0 == pending, > 0 == running */
  66   int a11y_bus_pid;
  67   char *a11y_bus_address;
  68   int pipefd[2];
  69   char *a11y_launch_error_message;
  70 } A11yBusLauncher;
  71
  72 static A11yBusLauncher *_global_app = NULL;
  73
  74 static const gchar introspection_xml[] =
  75   "<node>"
  76   "  <interface name='org.a11y.Bus'>"
  77   "    <method name='GetAddress'>"
  78   "      <arg type='s' name='address' direction='out'/>"
  79   "    </method>"
  80   "  </interface>"
  81   "<interface name='org.a11y.Status'>"
  82   "<property name='IsEnabled' type='b' access='readwrite'/>"
  83   "<property name='ScreenReaderEnabled' type='b' access='readwrite'/>"
  84   "</interface>"
  85   "</node>";
  86 static GDBusNodeInfo *introspection_data = NULL;
  87
  88 static void
  89 setup_bus_child (gpointer data)
  90 {
  91   A11yBusLauncher *app = data;
  92   (void) app;
  93
  94   close (app->pipefd[0]);
  95   dup2 (app->pipefd[1], 3);
  96   close (app->pipefd[1]);
  97
  98   /* On Linux, tell the bus process to exit if this process goes away */
  99 #ifdef __linux
 100 #include <sys/prctl.h>
 101   prctl (PR_SET_PDEATHSIG, 15);
 102 #endif
 103 }
 104
 105 /**
 106  * unix_read_all_fd_to_string:
 107  *
 108  * Read all data from a file descriptor to a C string buffer.
 109  */
 110 static gboolean
 111 unix_read_all_fd_to_string (int      fd,
 112                             char    *buf,
 113                             ssize_t  max_bytes)
 114 {
 115   ssize_t bytes_read;
 116
 117   while (max_bytes > 1 && (bytes_read = read (fd, buf, MAX (4096, max_bytes - 1))))
 118     {
 119       if (bytes_read < 0)
 120         return FALSE;
 121       buf += bytes_read;
 122       max_bytes -= bytes_read;
 123     }
 124   *buf = '\0';
 125   return TRUE;
 126 }
 127
 128 static void
 129 on_bus_exited (GPid     pid,
 130                gint     status,
 131                gpointer data)
 132 {
 133   A11yBusLauncher *app = data;
 134
 135   app->a11y_bus_pid = -1;
 136   app->state = A11Y_BUS_STATE_ERROR;
 137   if (app->a11y_launch_error_message == NULL)
 138     {
 139       if (WIFEXITED (status))
 140         app->a11y_launch_error_message = g_strdup_printf ("Bus exited with code %d", WEXITSTATUS (status));
 141       else if (WIFSIGNALED (status))
 142         app->a11y_launch_error_message = g_strdup_printf ("Bus killed by signal %d", WTERMSIG (status));
 143       else if (WIFSTOPPED (status))
 144         app->a11y_launch_error_message = g_strdup_printf ("Bus stopped by signal %d", WSTOPSIG (status));
 145     }
 146   g_main_loop_quit (app->loop);
 147 }
 148
 149 static gboolean
 150 ensure_a11y_bus (A11yBusLauncher *app)
 151 {
 152   GPid pid;
 153   char *argv[] = { DBUS_DAEMON, NULL, "--nofork", "--print-address", "3", NULL };
 154   char addr_buf[2048];
 155   GError *error = NULL;
 156
 157   if (app->a11y_bus_pid != 0)
 158     return FALSE;
 159
 160   argv[1] = g_strdup_printf ("--config-file=%s/at-spi2/accessibility.conf", SYSCONFDIR);
 161
 162   if (pipe (app->pipefd) < 0)
 163     g_error ("Failed to create pipe: %s", strerror (errno));
 164
 165   if (!g_spawn_async (NULL,
 166                       argv,
 167                       NULL,
 168                       G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD,
 169                       setup_bus_child,
 170                       app,
 171                       &pid,
 172                       &error))
 173     {
 174       app->a11y_bus_pid = -1;
 175       app->a11y_launch_error_message = g_strdup (error->message);
 176       g_clear_error (&error);
 177       goto error;
 178     }
 179
 180   close (app->pipefd[1]);
 181   app->pipefd[1] = -1;
 182
 183   g_child_watch_add (pid, on_bus_exited, app);
 184
 185   app->state = A11Y_BUS_STATE_READING_ADDRESS;
 186   app->a11y_bus_pid = pid;
 187   g_debug ("Launched a11y bus, child is %ld", (long) pid);
 188   if (!unix_read_all_fd_to_string (app->pipefd[0], addr_buf, sizeof (addr_buf)))
 189     {
 190       app->a11y_launch_error_message = g_strdup_printf ("Failed to read address: %s", strerror (errno));
 191       kill (app->a11y_bus_pid, SIGTERM);
 192       goto error;
 193     }
 194   close (app->pipefd[0]);
 195   app->pipefd[0] = -1;
 196   app->state = A11Y_BUS_STATE_RUNNING;
 197
 198   /* Trim the trailing newline */
 199   app->a11y_bus_address = g_strchomp (g_strdup (addr_buf));
 200   g_debug ("a11y bus address: %s", app->a11y_bus_address);
 201
 202 #ifdef HAVE_X11
 203   {
 204     Display *display = XOpenDisplay (NULL);
 205     if (display)
 206       {
 207         Atom bus_address_atom = XInternAtom (display, "AT_SPI_BUS", False);
 208         XChangeProperty (display,
 209                          XDefaultRootWindow (display),
 210                          bus_address_atom,
 211                          XA_STRING, 8, PropModeReplace,
 212                          (guchar *) app->a11y_bus_address, strlen (app->a11y_bus_address));
 213         XFlush (display);
 214         XCloseDisplay (display);
 215       }
 216   }
 217 #endif
 218
 219   return TRUE;
 220
 221  error:
 222   close (app->pipefd[0]);
 223   close (app->pipefd[1]);
 224   app->state = A11Y_BUS_STATE_ERROR;
 225
 226   return FALSE;
 227 }
 228
 229 static void
 230 handle_method_call (GDBusConnection       *connection,
 231                     const gchar           *sender,
 232                     const gchar           *object_path,
 233                     const gchar           *interface_name,
 234                     const gchar           *method_name,
 235                     GVariant              *parameters,
 236                     GDBusMethodInvocation *invocation,
 237                     gpointer               user_data)
 238 {
 239   A11yBusLauncher *app = user_data;
 240
 241   if (g_strcmp0 (method_name, "GetAddress") == 0)
 242     {
 243       ensure_a11y_bus (app);
 244       if (app->a11y_bus_pid > 0)
 245         g_dbus_method_invocation_return_value (invocation,
 246                                                g_variant_new ("(s)", app->a11y_bus_address));
 247       else
 248         g_dbus_method_invocation_return_dbus_error (invocation,
 249                                                     "org.a11y.Bus.Error",
 250                                                     app->a11y_launch_error_message);
 251     }
 252 }
 253
 254 static GVariant *
 255 handle_get_property  (GDBusConnection       *connection,
 256                       const gchar           *sender,
 257                       const gchar           *object_path,
 258                       const gchar           *interface_name,
 259                       const gchar           *property_name,
 260                     GError **error,
 261                     gpointer               user_data)
 262 {
 263   A11yBusLauncher *app = user_data;
 264
 265   if (g_strcmp0 (property_name, "IsEnabled") == 0)
 266     return g_variant_new ("b", app->a11y_enabled);
 267   else if (g_strcmp0 (property_name, "ScreenReaderEnabled") == 0)
 268     return g_variant_new ("b", app->screen_reader_enabled);
 269   else
 270     return NULL;
 271 }
 272
 273 static void
 274 handle_a11y_enabled_change (A11yBusLauncher *app, gboolean enabled,
 275                                gboolean notify_gsettings)
 276 {
 277   GVariantBuilder builder;
 278   GVariantBuilder invalidated_builder;
 279
 280   if (enabled == app->a11y_enabled)
 281     return;
 282
 283   app->a11y_enabled = enabled;
 284
 285   if (notify_gsettings && app->interface_schema)
 286     {
 287       g_settings_set_boolean (app->interface_schema, "toolkit-accessibility",
 288                               enabled);
 289       g_settings_sync ();
 290     }
 291
 292   g_variant_builder_init (&builder, G_VARIANT_TYPE_ARRAY);
 293   g_variant_builder_init (&invalidated_builder, G_VARIANT_TYPE ("as"));
 294   g_variant_builder_add (&builder, "{sv}", "IsEnabled",
 295                          g_variant_new_boolean (enabled));
 296
 297   g_dbus_connection_emit_signal (app->session_bus, NULL, "/org/a11y/bus",
 298                                  "org.freedesktop.DBus.Properties",
 299                                  "PropertiesChanged",
 300                                  g_variant_new ("(sa{sv}as)", "org.a11y.Status",
 301                                                 &builder,
 302                                                 &invalidated_builder),
 303                                  NULL);
 304 }
 305
 306 static void
 307 handle_screen_reader_enabled_change (A11yBusLauncher *app, gboolean enabled,
 308                                gboolean notify_gsettings)
 309 {
 310   GVariantBuilder builder;
 311   GVariantBuilder invalidated_builder;
 312
 313   if (enabled == app->screen_reader_enabled)
 314     return;
 315
 316   /* If the screen reader is being enabled, we should enable accessibility
 317    * if it isn't enabled already */
 318   if (enabled)
 319     handle_a11y_enabled_change (app, enabled, notify_gsettings);
 320
 321   app->screen_reader_enabled = enabled;
 322
 323   if (notify_gsettings && app->a11y_schema)
 324     {
 325       g_settings_set_boolean (app->a11y_schema, "screen-reader-enabled",
 326                               enabled);
 327       g_settings_sync ();
 328     }
 329
 330   g_variant_builder_init (&builder, G_VARIANT_TYPE_ARRAY);
 331   g_variant_builder_init (&invalidated_builder, G_VARIANT_TYPE ("as"));
 332   g_variant_builder_add (&builder, "{sv}", "ScreenReaderEnabled",
 333                          g_variant_new_boolean (enabled));
 334
 335   g_dbus_connection_emit_signal (app->session_bus, NULL, "/org/a11y/bus",
 336                                  "org.freedesktop.DBus.Properties",
 337                                  "PropertiesChanged",
 338                                  g_variant_new ("(sa{sv}as)", "org.a11y.Status",
 339                                                 &builder,
 340                                                 &invalidated_builder),
 341                                  NULL);
 342 }
 343
 344 static gboolean
 345 handle_set_property  (GDBusConnection       *connection,
 346                       const gchar           *sender,
 347                       const gchar           *object_path,
 348                       const gchar           *interface_name,
 349                       const gchar           *property_name,
 350                       GVariant *value,
 351                     GError **error,
 352                     gpointer               user_data)
 353 {
 354   A11yBusLauncher *app = user_data;
 355   const gchar *type = g_variant_get_type_string (value);
 356   gboolean enabled;
 357
 358   if (g_strcmp0 (type, "b") != 0)
 359     {
 360       g_set_error (error, G_DBUS_ERROR, G_DBUS_ERROR_INVALID_ARGS,
 361                        "org.a11y.Status.%s expects a boolean but got %s", property_name, type);
 362       return FALSE;
 363     }
 364
 365   enabled = g_variant_get_boolean (value);
 366
 367   if (g_strcmp0 (property_name, "IsEnabled") == 0)
 368     {
 369       handle_a11y_enabled_change (app, enabled, TRUE);
 370       return TRUE;
 371     }
 372   else if (g_strcmp0 (property_name, "ScreenReaderEnabled") == 0)
 373     {
 374       handle_screen_reader_enabled_change (app, enabled, TRUE);
 375       return TRUE;
 376     }
 377   else
 378     {
 379       g_set_error (error, G_DBUS_ERROR, G_DBUS_ERROR_INVALID_ARGS,
 380                        "Unknown property '%s'", property_name);
 381       return FALSE;
 382     }
 383 }
 384
 385 static const GDBusInterfaceVTable bus_vtable =
 386 {
 387   handle_method_call,
 388   NULL, /* handle_get_property, */
 389   NULL  /* handle_set_property */
 390 };
 391
 392 static const GDBusInterfaceVTable status_vtable =
 393 {
 394   NULL, /* handle_method_call */
 395   handle_get_property,
 396   handle_set_property
 397 };
 398
 399 static void
 400 on_bus_acquired (GDBusConnection *connection,
 401                  const gchar     *name,
 402                  gpointer         user_data)
 403 {
 404   A11yBusLauncher *app = user_data;
 405   GError *error;
 406   guint registration_id;
 407
 408   if (connection == NULL)
 409     {
 410       g_main_loop_quit (app->loop);
 411       return;
 412     }
 413   app->session_bus = connection;
 414
 415   if (app->launch_immediately)
 416     {
 417       ensure_a11y_bus (app);
 418       if (app->state == A11Y_BUS_STATE_ERROR)
 419         {
 420           g_main_loop_quit (app->loop);
 421           return;
 422         }
 423     }
 424
 425   error = NULL;
 426   registration_id = g_dbus_connection_register_object (connection,
 427                                                        "/org/a11y/bus",
 428                                                        introspection_data->interfaces[0],
 429                                                        &bus_vtable,
 430                                                        _global_app,
 431                                                        NULL,
 432                                                        &error);
 433   if (registration_id == 0)
 434     {
 435       g_error ("%s", error->message);
 436       g_clear_error (&error);
 437     }
 438
 439   g_dbus_connection_register_object (connection,
 440                                      "/org/a11y/bus",
 441                                      introspection_data->interfaces[1],
 442                                      &status_vtable,
 443                                      _global_app,
 444                                      NULL,
 445                                      NULL);
 446 }
 447
 448 static void
 449 on_name_lost (GDBusConnection *connection,
 450               const gchar     *name,
 451               gpointer         user_data)
 452 {
 453   A11yBusLauncher *app = user_data;
 454   if (app->session_bus == NULL
 455       && connection == NULL
 456       && app->a11y_launch_error_message == NULL)
 457     app->a11y_launch_error_message = g_strdup ("Failed to connect to session bus");
 458   g_main_loop_quit (app->loop);
 459 }
 460
 461 static void
 462 on_name_acquired (GDBusConnection *connection,
 463                   const gchar     *name,
 464                   gpointer         user_data)
 465 {
 466   A11yBusLauncher *app = user_data;
 467   (void) app;
 468 }
 469
 470 static int sigterm_pipefd[2];
 471
 472 static void
 473 sigterm_handler (int signum)
 474 {
 475   write (sigterm_pipefd[1], "X", 1);
 476 }
 477
 478 static gboolean
 479 on_sigterm_pipe (GIOChannel  *channel,
 480                  GIOCondition condition,
 481                  gpointer     data)
 482 {
 483   A11yBusLauncher *app = data;
 484
 485   g_main_loop_quit (app->loop);
 486
 487   return FALSE;
 488 }
 489
 490 static void
 491 init_sigterm_handling (A11yBusLauncher *app)
 492 {
 493   GIOChannel *sigterm_channel;
 494
 495   if (pipe (sigterm_pipefd) < 0)
 496     g_error ("Failed to create pipe: %s", strerror (errno));
 497   signal (SIGTERM, sigterm_handler);
 498
 499   sigterm_channel = g_io_channel_unix_new (sigterm_pipefd[0]);
 500   g_io_add_watch (sigterm_channel,
 501                   G_IO_IN | G_IO_ERR | G_IO_HUP,
 502                   on_sigterm_pipe,
 503                   app);
 504 }
 505
 506 static gboolean
 507 already_running ()
 508 {
 509 #ifdef HAVE_X11
 510   Atom AT_SPI_BUS;
 511   Atom actual_type;
 512   Display *bridge_display;
 513   int actual_format;
 514   unsigned char *data = NULL;
 515   unsigned long nitems;
 516   unsigned long leftover;
 517   gboolean result = FALSE;
 518
 519   bridge_display = XOpenDisplay (NULL);
 520   if (!bridge_display)
 521               return FALSE;
 522
 523   AT_SPI_BUS = XInternAtom (bridge_display, "AT_SPI_BUS", False);
 524   XGetWindowProperty (bridge_display,
 525                       XDefaultRootWindow (bridge_display),
 526                       AT_SPI_BUS, 0L,
 527                       (long) BUFSIZ, False,
 528                       (Atom) 31, &actual_type, &actual_format,
 529                       &nitems, &leftover, &data);
 530
 531   if (data)
 532   {
 533     GDBusConnection *bus;
 534     bus = g_dbus_connection_new_for_address_sync ((const gchar *)data, 0,
 535                                                   NULL, NULL, NULL);
 536     if (bus != NULL)
 537       {
 538         result = TRUE;
 539         g_object_unref (bus);
 540       }
 541   }
 542
 543   XCloseDisplay (bridge_display);
 544   return result;
 545 #else
 546   return FALSE;
 547 #endif
 548 }
 549
 550 static GSettings *
 551 get_schema (const gchar *name)
 552 {
 553   const char * const *schemas = NULL;
 554   gint i;
 555
 556   schemas = g_settings_list_schemas ();
 557   for (i = 0; schemas[i]; i++)
 558   {
 559     if (!strcmp (schemas[i], name))
 560       return g_settings_new (schemas[i]);
 561   }
 562
 563   return NULL;
 564 }
 565
 566 static void
 567 gsettings_key_changed (GSettings *gsettings, const gchar *key, void *user_data)
 568 {
 569   gboolean new_val = g_settings_get_boolean (gsettings, key);
 570   A11yBusLauncher *app = user_data;
 571
 572   if (!strcmp (key, "toolkit-accessibility"))
 573     handle_a11y_enabled_change (_global_app, new_val, FALSE);
 574   else if (!strcmp (key, "screen-reader-enabled"))
 575     handle_screen_reader_enabled_change (_global_app, new_val, FALSE);
 576 }
 577
 578 static gboolean
 579 _launch_screen_reader(A11yBusLauncher *bl)
 580 {
 581    bundle *kb = NULL;
 582    gboolean ret = FALSE;
 583
 584    kb = bundle_create();
 585    if (kb == NULL)
 586      return FALSE;
 587
 588    bl->pid = aul_launch_app("org.tizen.screen-reader", kb);
 589    if (bl->pid >= 0) {
 590        ret = TRUE;
 591    }
 592
 593    bundle_free(kb);
 594    return ret;
 595 }
 596
 597 static gboolean
 598 _terminate_screen_reader(A11yBusLauncher *bl)
 599 {
 600    int ret;
 601    if (bl->pid <= 0)
 602      return FALSE;
 603
 604
 605    int status = aul_app_get_status_bypid(bl->pid);
 606
 607    if (status < 0)
 608      {
 609         LOGD("App with pid %d already terminated", bl->pid);
 610         bl->pid = 0;
 611         return TRUE;
 612      }
 613
 614    LOGD("terminate process with pid %d", bl->pid);
 615    if (!aul_terminate_pid(bl->pid))
 616      {
 617         bl->pid = 0;
 618         return TRUE;
 619      }
 620
 621    LOGD("Unable to terminate process using aul api. Sending SIGTERM signal");
 622    ret = kill(bl->pid, SIGTERM);
 623    if (!ret)
 624      {
 625         bl->pid = 0;
 626         return TRUE;
 627      }
 628
 629    LOGD("Unable to terminate process: %d with api or signal.", bl->pid);
 630    return FALSE;
 631 }
 632
 633 void screen_reader_cb(keynode_t *node, void *user_data)
 634 {
 635    A11yBusLauncher *bl = user_data;
 636    int ret;
 637
 638    ret = vconf_keynode_get_bool(node);
 639    if (ret < 0)
 640      return;
 641
 642    bl->screen_reader_needed = ret;
 643
 644    if (!bl->screen_reader_needed && (bl->pid > 0))
 645      _terminate_screen_reader(bl);
 646    else if (bl->screen_reader_needed && (bl->pid <= 0))
 647      _launch_screen_reader(bl);
 648 }
 649
 650 int
 651 main (int    argc,
 652       char **argv)
 653 {
 654   GError *error = NULL;
 655   GMainLoop *loop;
 656   GDBusConnection *session_bus;
 657   int name_owner_id;
 658   gboolean a11y_set = FALSE;
 659   gboolean screen_reader_set = FALSE;
 660   gint i;
 661
 662   if (already_running ())
 663     return 0;
 664
 665   _global_app = g_slice_new0 (A11yBusLauncher);
 666   _global_app->loop = g_main_loop_new (NULL, FALSE);
 667
 668   for (i = 1; i < argc; i++)
 669     {
 670       if (!strcmp (argv[i], "--launch-immediately"))
 671         _global_app->launch_immediately = TRUE;
 672       else if (sscanf (argv[i], "--a11y=%d", &_global_app->a11y_enabled) == 2)
 673         a11y_set = TRUE;
 674       else if (sscanf (argv[i], "--screen-reader=%d",
 675                        &_global_app->screen_reader_enabled) == 2)
 676         screen_reader_set = TRUE;
 677     else
 678       g_error ("usage: %s [--launch-immediately] [--a11y=0|1] [--screen-reader=0|1]", argv[0]);
 679     }
 680
 681   _global_app->interface_schema = get_schema ("org.gnome.desktop.interface");
 682   _global_app->a11y_schema = get_schema ("org.gnome.desktop.a11y.applications");
 683
 684   if (!a11y_set)
 685     {
 686       _global_app->a11y_enabled = _global_app->interface_schema
 687                                   ? g_settings_get_boolean (_global_app->interface_schema, "toolkit-accessibility")
 688                                   : _global_app->launch_immediately;
 689     }
 690
 691   if (!screen_reader_set)
 692     {
 693       _global_app->screen_reader_enabled = _global_app->a11y_schema
 694                                   ? g_settings_get_boolean (_global_app->a11y_schema, "screen-reader-enabled")
 695                                   : FALSE;
 696     }
 697
 698   if (_global_app->interface_schema)
 699     g_signal_connect (_global_app->interface_schema,
 700                       "changed::toolkit-accessibility",
 701                       G_CALLBACK (gsettings_key_changed), _global_app);
 702
 703   if (_global_app->a11y_schema)
 704     g_signal_connect (_global_app->a11y_schema,
 705                       "changed::screen-reader-enabled",
 706                       G_CALLBACK (gsettings_key_changed), _global_app);
 707
 708   init_sigterm_handling (_global_app);
 709
 710   introspection_data = g_dbus_node_info_new_for_xml (introspection_xml, NULL);
 711   g_assert (introspection_data != NULL);
 712
 713   name_owner_id = g_bus_own_name (G_BUS_TYPE_SESSION,
 714                                   "org.a11y.Bus",
 715                                   G_BUS_NAME_OWNER_FLAGS_ALLOW_REPLACEMENT,
 716                                   on_bus_acquired,
 717                                   on_name_acquired,
 718                                   on_name_lost,
 719                                   _global_app,
 720                                   NULL);
 721
 722   int ret = vconf_get_bool(VCONFKEY_SETAPPL_ACCESSIBILITY_TTS, &_global_app->screen_reader_needed);
 723   if (ret != 0)
 724     {
 725       LOGD("Could not read VCONFKEY_SETAPPL_ACCESSIBILITY_TTS key value.\n");
 726       return FALSE;
 727     }
 728   ret = vconf_notify_key_changed(VCONFKEY_SETAPPL_ACCESSIBILITY_TTS, screen_reader_cb, _global_app);
 729   if(ret != 0)
 730     {
 731       LOGD("Could not add information level callback\n");
 732       return FALSE;
 733     }
 734   if (_global_app->screen_reader_needed)
 735     _launch_screen_reader(_global_app);
 736
 737   g_main_loop_run (_global_app->loop);
 738
 739   if (_global_app->a11y_bus_pid > 0)
 740     kill (_global_app->a11y_bus_pid, SIGTERM);
 741
 742   /* Clear the X property if our bus is gone; in the case where e.g.
 743    * GDM is launching a login on an X server it was using before,
 744    * we don't want early login processes to pick up the stale address.
 745    */
 746 #ifdef HAVE_X11
 747   {
 748     Display *display = XOpenDisplay (NULL);
 749     if (display)
 750       {
 751         Atom bus_address_atom = XInternAtom (display, "AT_SPI_BUS", False);
 752         XDeleteProperty (display,
 753                          XDefaultRootWindow (display),
 754                          bus_address_atom);
 755
 756         XFlush (display);
 757         XCloseDisplay (display);
 758       }
 759   }
 760 #endif
 761
 762   if (_global_app->a11y_launch_error_message)
 763     {
 764       g_printerr ("Failed to launch bus: %s", _global_app->a11y_launch_error_message);
 765       return 1;
 766     }
 767   return 0;
 768 }