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 typedef enum {
  39   A11Y_BUS_STATE_IDLE = 0,
  40   A11Y_BUS_STATE_READING_ADDRESS,
  41   A11Y_BUS_STATE_RUNNING,
  42   A11Y_BUS_STATE_ERROR
  43 } A11yBusState;
  44
  45 typedef struct {
  46   GMainLoop *loop;
  47   gboolean launch_immediately;
  48   gboolean a11y_enabled;
  49   gboolean screen_reader_enabled;
  50   GDBusConnection *session_bus;
  51   GSettings *a11y_schema;
  52   GSettings *interface_schema;
  53
  54   GDBusProxy *client_proxy;
  55
  56   A11yBusState state;
  57   /* -1 == error, 0 == pending, > 0 == running */
  58   int a11y_bus_pid;
  59   char *a11y_bus_address;
  60   int pipefd[2];
  61   char *a11y_launch_error_message;
  62 } A11yBusLauncher;
  63
  64 static A11yBusLauncher *_global_app = NULL;
  65
  66 static const gchar introspection_xml[] =
  67   "<node>"
  68   "  <interface name='org.a11y.Bus'>"
  69   "    <method name='GetAddress'>"
  70   "      <arg type='s' name='address' direction='out'/>"
  71   "    </method>"
  72   "  </interface>"
  73   "<interface name='org.a11y.Status'>"
  74   "<property name='IsEnabled' type='b' access='readwrite'/>"
  75   "<property name='ScreenReaderEnabled' type='b' access='readwrite'/>"
  76   "</interface>"
  77   "</node>";
  78 static GDBusNodeInfo *introspection_data = NULL;
  79
  80 static void
  81 respond_to_end_session (GDBusProxy *proxy)
  82 {
  83   GVariant *parameters;
  84
  85   parameters = g_variant_new ("(bs)", TRUE, "");
  86
  87   g_dbus_proxy_call (proxy,
  88                      "EndSessionResponse", parameters,
  89                      G_DBUS_CALL_FLAGS_NONE,
  90                      -1, NULL, NULL, NULL);
  91 }
  92
  93 static void
  94 g_signal_cb (GDBusProxy *proxy,
  95              gchar      *sender_name,
  96              gchar      *signal_name,
  97              GVariant   *parameters,
  98              gpointer    user_data)
  99 {
 100   A11yBusLauncher *app = user_data;
 101
 102   if (g_strcmp0 (signal_name, "QueryEndSession") == 0)
 103     respond_to_end_session (proxy);
 104   else if (g_strcmp0 (signal_name, "EndSession") == 0)
 105     respond_to_end_session (proxy);
 106   else if (g_strcmp0 (signal_name, "Stop") == 0)
 107     g_main_loop_quit (app->loop);
 108 }
 109
 110 static void
 111 client_proxy_ready_cb (GObject      *source_object,
 112                        GAsyncResult *res,
 113                        gpointer      user_data)
 114 {
 115   A11yBusLauncher *app = user_data;
 116   GError *error = NULL;
 117
 118   app->client_proxy = g_dbus_proxy_new_for_bus_finish (res, &error);
 119
 120   if (error != NULL)
 121     {
 122       g_warning ("Failed to get a client proxy: %s", error->message);
 123       g_error_free (error);
 124
 125       return;
 126     }
 127
 128   g_signal_connect (app->client_proxy, "g-signal",
 129                     G_CALLBACK (g_signal_cb), app);
 130 }
 131
 132 static void
 133 register_client (A11yBusLauncher *app)
 134 {
 135   GDBusProxyFlags flags;
 136   GDBusProxy *sm_proxy;
 137   GError *error;
 138   const gchar *app_id;
 139   const gchar *autostart_id;
 140   gchar *client_startup_id;
 141   GVariant *parameters;
 142   GVariant *variant;
 143   gchar *object_path;
 144
 145   flags = G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES |
 146           G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS;
 147
 148   error = NULL;
 149   sm_proxy = g_dbus_proxy_new_sync (app->session_bus, flags, NULL,
 150                                     "org.gnome.SessionManager",
 151                                     "/org/gnome/SessionManager",
 152                                     "org.gnome.SessionManager",
 153                                     NULL, &error);
 154
 155   if (error != NULL)
 156     {
 157       g_warning ("Failed to get session manager proxy: %s", error->message);
 158       g_error_free (error);
 159
 160       return;
 161     }
 162
 163   app_id = "at-spi-bus-launcher";
 164   autostart_id = g_getenv ("DESKTOP_AUTOSTART_ID");
 165
 166   if (autostart_id != NULL)
 167     {
 168       client_startup_id = g_strdup (autostart_id);
 169       g_unsetenv ("DESKTOP_AUTOSTART_ID");
 170     }
 171   else
 172     {
 173       client_startup_id = g_strdup ("");
 174     }
 175
 176   parameters = g_variant_new ("(ss)", app_id, client_startup_id);
 177   g_free (client_startup_id);
 178
 179   error = NULL;
 180   variant = g_dbus_proxy_call_sync (sm_proxy,
 181                                     "RegisterClient", parameters,
 182                                     G_DBUS_CALL_FLAGS_NONE,
 183                                     -1, NULL, &error);
 184
 185   g_object_unref (sm_proxy);
 186
 187   if (error != NULL)
 188     {
 189       g_warning ("Failed to register client: %s", error->message);
 190       g_error_free (error);
 191
 192       return;
 193     }
 194
 195   g_variant_get (variant, "(o)", &object_path);
 196   g_variant_unref (variant);
 197
 198   flags = G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES;
 199   g_dbus_proxy_new_for_bus (G_BUS_TYPE_SESSION, flags, NULL,
 200                             "org.gnome.SessionManager", object_path,
 201                             "org.gnome.SessionManager.ClientPrivate",
 202                             NULL, client_proxy_ready_cb, app);
 203
 204   g_free (object_path);
 205 }
 206
 207 static void
 208 name_appeared_handler (GDBusConnection *connection,
 209                        const gchar     *name,
 210                        const gchar     *name_owner,
 211                        gpointer         user_data)
 212 {
 213   A11yBusLauncher *app = user_data;
 214
 215   register_client (app);
 216 }
 217
 218 static void
 219 setup_bus_child (gpointer data)
 220 {
 221   A11yBusLauncher *app = data;
 222   (void) app;
 223
 224   close (app->pipefd[0]);
 225   dup2 (app->pipefd[1], 3);
 226   close (app->pipefd[1]);
 227
 228   /* On Linux, tell the bus process to exit if this process goes away */
 229 #ifdef __linux
 230 #include <sys/prctl.h>
 231   prctl (PR_SET_PDEATHSIG, 15);
 232 #endif
 233 }
 234
 235 /**
 236  * unix_read_all_fd_to_string:
 237  *
 238  * Read all data from a file descriptor to a C string buffer.
 239  */
 240 static gboolean
 241 unix_read_all_fd_to_string (int      fd,
 242                             char    *buf,
 243                             ssize_t  max_bytes)
 244 {
 245   ssize_t bytes_read;
 246
 247   while (max_bytes > 1 && (bytes_read = read (fd, buf, MAX (4096, max_bytes - 1))))
 248     {
 249       if (bytes_read < 0)
 250         return FALSE;
 251       buf += bytes_read;
 252       max_bytes -= bytes_read;
 253     }
 254   *buf = '\0';
 255   return TRUE;
 256 }
 257
 258 static void
 259 on_bus_exited (GPid     pid,
 260                gint     status,
 261                gpointer data)
 262 {
 263   A11yBusLauncher *app = data;
 264
 265   app->a11y_bus_pid = -1;
 266   app->state = A11Y_BUS_STATE_ERROR;
 267   if (app->a11y_launch_error_message == NULL)
 268     {
 269       if (WIFEXITED (status))
 270         app->a11y_launch_error_message = g_strdup_printf ("Bus exited with code %d", WEXITSTATUS (status));
 271       else if (WIFSIGNALED (status))
 272         app->a11y_launch_error_message = g_strdup_printf ("Bus killed by signal %d", WTERMSIG (status));
 273       else if (WIFSTOPPED (status))
 274         app->a11y_launch_error_message = g_strdup_printf ("Bus stopped by signal %d", WSTOPSIG (status));
 275     }
 276   g_main_loop_quit (app->loop);
 277 }
 278
 279 static gboolean
 280 ensure_a11y_bus (A11yBusLauncher *app)
 281 {
 282   GPid pid;
 283   char *argv[] = { DBUS_DAEMON, NULL, "--nofork", "--print-address", "3", NULL };
 284   char addr_buf[2048];
 285   GError *error = NULL;
 286   const char *config_path = NULL;
 287
 288   if (app->a11y_bus_pid != 0)
 289     return FALSE;
 290
 291   if (g_file_test (SYSCONFDIR"/at-spi2/accessibility.conf", G_FILE_TEST_EXISTS))
 292       config_path = "--config-file="SYSCONFDIR"/at-spi2/accessibility.conf";
 293   else
 294       config_path = "--config-file="DATADIR"/defaults/at-spi2/accessibility.conf";
 295
 296   argv[1] = config_path;
 297
 298   if (pipe (app->pipefd) < 0)
 299     g_error ("Failed to create pipe: %s", strerror (errno));
 300
 301   if (!g_spawn_async (NULL,
 302                       argv,
 303                       NULL,
 304                       G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD,
 305                       setup_bus_child,
 306                       app,
 307                       &pid,
 308                       &error))
 309     {
 310       app->a11y_bus_pid = -1;
 311       app->a11y_launch_error_message = g_strdup (error->message);
 312       g_clear_error (&error);
 313       goto error;
 314     }
 315
 316   close (app->pipefd[1]);
 317   app->pipefd[1] = -1;
 318
 319   g_child_watch_add (pid, on_bus_exited, app);
 320
 321   app->state = A11Y_BUS_STATE_READING_ADDRESS;
 322   app->a11y_bus_pid = pid;
 323   g_debug ("Launched a11y bus, child is %ld", (long) pid);
 324   if (!unix_read_all_fd_to_string (app->pipefd[0], addr_buf, sizeof (addr_buf)))
 325     {
 326       app->a11y_launch_error_message = g_strdup_printf ("Failed to read address: %s", strerror (errno));
 327       kill (app->a11y_bus_pid, SIGTERM);
 328       goto error;
 329     }
 330   close (app->pipefd[0]);
 331   app->pipefd[0] = -1;
 332   app->state = A11Y_BUS_STATE_RUNNING;
 333
 334   /* Trim the trailing newline */
 335   app->a11y_bus_address = g_strchomp (g_strdup (addr_buf));
 336   g_debug ("a11y bus address: %s", app->a11y_bus_address);
 337
 338 #ifdef HAVE_X11
 339   {
 340     Display *display = XOpenDisplay (NULL);
 341     if (display)
 342       {
 343         Atom bus_address_atom = XInternAtom (display, "AT_SPI_BUS", False);
 344         XChangeProperty (display,
 345                          XDefaultRootWindow (display),
 346                          bus_address_atom,
 347                          XA_STRING, 8, PropModeReplace,
 348                          (guchar *) app->a11y_bus_address, strlen (app->a11y_bus_address));
 349         XFlush (display);
 350         XCloseDisplay (display);
 351       }
 352   }
 353 #endif
 354
 355   return TRUE;
 356
 357  error:
 358   close (app->pipefd[0]);
 359   close (app->pipefd[1]);
 360   app->state = A11Y_BUS_STATE_ERROR;
 361
 362   return FALSE;
 363 }
 364
 365 static void
 366 handle_method_call (GDBusConnection       *connection,
 367                     const gchar           *sender,
 368                     const gchar           *object_path,
 369                     const gchar           *interface_name,
 370                     const gchar           *method_name,
 371                     GVariant              *parameters,
 372                     GDBusMethodInvocation *invocation,
 373                     gpointer               user_data)
 374 {
 375   A11yBusLauncher *app = user_data;
 376
 377   if (g_strcmp0 (method_name, "GetAddress") == 0)
 378     {
 379       ensure_a11y_bus (app);
 380       if (app->a11y_bus_pid > 0)
 381         g_dbus_method_invocation_return_value (invocation,
 382                                                g_variant_new ("(s)", app->a11y_bus_address));
 383       else
 384         g_dbus_method_invocation_return_dbus_error (invocation,
 385                                                     "org.a11y.Bus.Error",
 386                                                     app->a11y_launch_error_message);
 387     }
 388 }
 389
 390 static GVariant *
 391 handle_get_property  (GDBusConnection       *connection,
 392                       const gchar           *sender,
 393                       const gchar           *object_path,
 394                       const gchar           *interface_name,
 395                       const gchar           *property_name,
 396                     GError **error,
 397                     gpointer               user_data)
 398 {
 399   A11yBusLauncher *app = user_data;
 400
 401   if (g_strcmp0 (property_name, "IsEnabled") == 0)
 402     return g_variant_new ("b", app->a11y_enabled);
 403   else if (g_strcmp0 (property_name, "ScreenReaderEnabled") == 0)
 404     return g_variant_new ("b", app->screen_reader_enabled);
 405   else
 406     return NULL;
 407 }
 408
 409 static void
 410 handle_a11y_enabled_change (A11yBusLauncher *app, gboolean enabled,
 411                                gboolean notify_gsettings)
 412 {
 413   GVariantBuilder builder;
 414   GVariantBuilder invalidated_builder;
 415
 416   if (enabled == app->a11y_enabled)
 417     return;
 418
 419   app->a11y_enabled = enabled;
 420
 421   if (notify_gsettings && app->interface_schema)
 422     {
 423       g_settings_set_boolean (app->interface_schema, "toolkit-accessibility",
 424                               enabled);
 425       g_settings_sync ();
 426     }
 427
 428   g_variant_builder_init (&builder, G_VARIANT_TYPE_ARRAY);
 429   g_variant_builder_init (&invalidated_builder, G_VARIANT_TYPE ("as"));
 430   g_variant_builder_add (&builder, "{sv}", "IsEnabled",
 431                          g_variant_new_boolean (enabled));
 432
 433   g_dbus_connection_emit_signal (app->session_bus, NULL, "/org/a11y/bus",
 434                                  "org.freedesktop.DBus.Properties",
 435                                  "PropertiesChanged",
 436                                  g_variant_new ("(sa{sv}as)", "org.a11y.Status",
 437                                                 &builder,
 438                                                 &invalidated_builder),
 439                                  NULL);
 440 }
 441
 442 static void
 443 handle_screen_reader_enabled_change (A11yBusLauncher *app, gboolean enabled,
 444                                gboolean notify_gsettings)
 445 {
 446   GVariantBuilder builder;
 447   GVariantBuilder invalidated_builder;
 448
 449   if (enabled == app->screen_reader_enabled)
 450     return;
 451
 452   /* If the screen reader is being enabled, we should enable accessibility
 453    * if it isn't enabled already */
 454   if (enabled)
 455     handle_a11y_enabled_change (app, enabled, notify_gsettings);
 456
 457   app->screen_reader_enabled = enabled;
 458
 459   if (notify_gsettings && app->a11y_schema)
 460     {
 461       g_settings_set_boolean (app->a11y_schema, "screen-reader-enabled",
 462                               enabled);
 463       g_settings_sync ();
 464     }
 465
 466   g_variant_builder_init (&builder, G_VARIANT_TYPE_ARRAY);
 467   g_variant_builder_init (&invalidated_builder, G_VARIANT_TYPE ("as"));
 468   g_variant_builder_add (&builder, "{sv}", "ScreenReaderEnabled",
 469                          g_variant_new_boolean (enabled));
 470
 471   g_dbus_connection_emit_signal (app->session_bus, NULL, "/org/a11y/bus",
 472                                  "org.freedesktop.DBus.Properties",
 473                                  "PropertiesChanged",
 474                                  g_variant_new ("(sa{sv}as)", "org.a11y.Status",
 475                                                 &builder,
 476                                                 &invalidated_builder),
 477                                  NULL);
 478 }
 479
 480 static gboolean
 481 handle_set_property  (GDBusConnection       *connection,
 482                       const gchar           *sender,
 483                       const gchar           *object_path,
 484                       const gchar           *interface_name,
 485                       const gchar           *property_name,
 486                       GVariant *value,
 487                     GError **error,
 488                     gpointer               user_data)
 489 {
 490   A11yBusLauncher *app = user_data;
 491   const gchar *type = g_variant_get_type_string (value);
 492   gboolean enabled;
 493
 494   if (g_strcmp0 (type, "b") != 0)
 495     {
 496       g_set_error (error, G_DBUS_ERROR, G_DBUS_ERROR_INVALID_ARGS,
 497                        "org.a11y.Status.%s expects a boolean but got %s", property_name, type);
 498       return FALSE;
 499     }
 500
 501   enabled = g_variant_get_boolean (value);
 502
 503   if (g_strcmp0 (property_name, "IsEnabled") == 0)
 504     {
 505       handle_a11y_enabled_change (app, enabled, TRUE);
 506       return TRUE;
 507     }
 508   else if (g_strcmp0 (property_name, "ScreenReaderEnabled") == 0)
 509     {
 510       handle_screen_reader_enabled_change (app, enabled, TRUE);
 511       return TRUE;
 512     }
 513   else
 514     {
 515       g_set_error (error, G_DBUS_ERROR, G_DBUS_ERROR_INVALID_ARGS,
 516                        "Unknown property '%s'", property_name);
 517       return FALSE;
 518     }
 519 }
 520
 521 static const GDBusInterfaceVTable bus_vtable =
 522 {
 523   handle_method_call,
 524   NULL, /* handle_get_property, */
 525   NULL  /* handle_set_property */
 526 };
 527
 528 static const GDBusInterfaceVTable status_vtable =
 529 {
 530   NULL, /* handle_method_call */
 531   handle_get_property,
 532   handle_set_property
 533 };
 534
 535 static void
 536 on_bus_acquired (GDBusConnection *connection,
 537                  const gchar     *name,
 538                  gpointer         user_data)
 539 {
 540   A11yBusLauncher *app = user_data;
 541   GError *error;
 542   guint registration_id;
 543
 544   if (connection == NULL)
 545     {
 546       g_main_loop_quit (app->loop);
 547       return;
 548     }
 549   app->session_bus = connection;
 550
 551   if (app->launch_immediately)
 552     {
 553       ensure_a11y_bus (app);
 554       if (app->state == A11Y_BUS_STATE_ERROR)
 555         {
 556           g_main_loop_quit (app->loop);
 557           return;
 558         }
 559     }
 560
 561   error = NULL;
 562   registration_id = g_dbus_connection_register_object (connection,
 563                                                        "/org/a11y/bus",
 564                                                        introspection_data->interfaces[0],
 565                                                        &bus_vtable,
 566                                                        _global_app,
 567                                                        NULL,
 568                                                        &error);
 569   if (registration_id == 0)
 570     {
 571       g_error ("%s", error->message);
 572       g_clear_error (&error);
 573     }
 574
 575   g_dbus_connection_register_object (connection,
 576                                      "/org/a11y/bus",
 577                                      introspection_data->interfaces[1],
 578                                      &status_vtable,
 579                                      _global_app,
 580                                      NULL,
 581                                      NULL);
 582 }
 583
 584 static void
 585 on_name_lost (GDBusConnection *connection,
 586               const gchar     *name,
 587               gpointer         user_data)
 588 {
 589   A11yBusLauncher *app = user_data;
 590   if (app->session_bus == NULL
 591       && connection == NULL
 592       && app->a11y_launch_error_message == NULL)
 593     app->a11y_launch_error_message = g_strdup ("Failed to connect to session bus");
 594   g_main_loop_quit (app->loop);
 595 }
 596
 597 static void
 598 on_name_acquired (GDBusConnection *connection,
 599                   const gchar     *name,
 600                   gpointer         user_data)
 601 {
 602   g_bus_watch_name (G_BUS_TYPE_SESSION,
 603                     "org.gnome.SessionManager",
 604                     G_BUS_NAME_WATCHER_FLAGS_NONE,
 605                     name_appeared_handler, NULL,
 606                     user_data, NULL);
 607 }
 608
 609 static int sigterm_pipefd[2];
 610
 611 static void
 612 sigterm_handler (int signum)
 613 {
 614   write (sigterm_pipefd[1], "X", 1);
 615 }
 616
 617 static gboolean
 618 on_sigterm_pipe (GIOChannel  *channel,
 619                  GIOCondition condition,
 620                  gpointer     data)
 621 {
 622   A11yBusLauncher *app = data;
 623
 624   g_main_loop_quit (app->loop);
 625
 626   return FALSE;
 627 }
 628
 629 static void
 630 init_sigterm_handling (A11yBusLauncher *app)
 631 {
 632   GIOChannel *sigterm_channel;
 633
 634   if (pipe (sigterm_pipefd) < 0)
 635     g_error ("Failed to create pipe: %s", strerror (errno));
 636   signal (SIGTERM, sigterm_handler);
 637
 638   sigterm_channel = g_io_channel_unix_new (sigterm_pipefd[0]);
 639   g_io_add_watch (sigterm_channel,
 640                   G_IO_IN | G_IO_ERR | G_IO_HUP,
 641                   on_sigterm_pipe,
 642                   app);
 643 }
 644
 645 static gboolean
 646 already_running ()
 647 {
 648 #ifdef HAVE_X11
 649   Atom AT_SPI_BUS;
 650   Atom actual_type;
 651   Display *bridge_display;
 652   int actual_format;
 653   unsigned char *data = NULL;
 654   unsigned long nitems;
 655   unsigned long leftover;
 656   gboolean result = FALSE;
 657
 658   bridge_display = XOpenDisplay (NULL);
 659   if (!bridge_display)
 660               return FALSE;
 661
 662   AT_SPI_BUS = XInternAtom (bridge_display, "AT_SPI_BUS", False);
 663   XGetWindowProperty (bridge_display,
 664                       XDefaultRootWindow (bridge_display),
 665                       AT_SPI_BUS, 0L,
 666                       (long) BUFSIZ, False,
 667                       (Atom) 31, &actual_type, &actual_format,
 668                       &nitems, &leftover, &data);
 669
 670   if (data)
 671   {
 672     GDBusConnection *bus;
 673     bus = g_dbus_connection_new_for_address_sync ((const gchar *)data, 0,
 674                                                   NULL, NULL, NULL);
 675     if (bus != NULL)
 676       {
 677         result = TRUE;
 678         g_object_unref (bus);
 679       }
 680   }
 681
 682   XCloseDisplay (bridge_display);
 683   return result;
 684 #else
 685   return FALSE;
 686 #endif
 687 }
 688
 689 static GSettings *
 690 get_schema (const gchar *name)
 691 {
 692   const char * const *schemas = NULL;
 693   gint i;
 694
 695   schemas = g_settings_list_schemas ();
 696   for (i = 0; schemas[i]; i++)
 697   {
 698     if (!strcmp (schemas[i], name))
 699       return g_settings_new (schemas[i]);
 700   }
 701
 702   return NULL;
 703 }
 704
 705 static void
 706 gsettings_key_changed (GSettings *gsettings, const gchar *key, void *user_data)
 707 {
 708   gboolean new_val = g_settings_get_boolean (gsettings, key);
 709   A11yBusLauncher *app = user_data;
 710
 711   if (!strcmp (key, "toolkit-accessibility"))
 712     handle_a11y_enabled_change (_global_app, new_val, FALSE);
 713   else if (!strcmp (key, "screen-reader-enabled"))
 714     handle_screen_reader_enabled_change (_global_app, new_val, FALSE);
 715 }
 716
 717 int
 718 main (int    argc,
 719       char **argv)
 720 {
 721   GError *error = NULL;
 722   GMainLoop *loop;
 723   GDBusConnection *session_bus;
 724   int name_owner_id;
 725   gboolean a11y_set = FALSE;
 726   gboolean screen_reader_set = FALSE;
 727   gint i;
 728
 729   if (already_running ())
 730     return 0;
 731
 732   _global_app = g_slice_new0 (A11yBusLauncher);
 733   _global_app->loop = g_main_loop_new (NULL, FALSE);
 734
 735   for (i = 1; i < argc; i++)
 736     {
 737       if (!strcmp (argv[i], "--launch-immediately"))
 738         _global_app->launch_immediately = TRUE;
 739       else if (sscanf (argv[i], "--a11y=%d", &_global_app->a11y_enabled) == 1)
 740         a11y_set = TRUE;
 741       else if (sscanf (argv[i], "--screen-reader=%d",
 742                        &_global_app->screen_reader_enabled) == 1)
 743         screen_reader_set = TRUE;
 744     else
 745       g_error ("usage: %s [--launch-immediately] [--a11y=0|1] [--screen-reader=0|1]", argv[0]);
 746     }
 747
 748   _global_app->interface_schema = get_schema ("org.gnome.desktop.interface");
 749   _global_app->a11y_schema = get_schema ("org.gnome.desktop.a11y.applications");
 750
 751   if (!a11y_set)
 752     {
 753       _global_app->a11y_enabled = _global_app->interface_schema
 754                                   ? g_settings_get_boolean (_global_app->interface_schema, "toolkit-accessibility")
 755                                   : _global_app->launch_immediately;
 756     }
 757
 758   if (!screen_reader_set)
 759     {
 760       _global_app->screen_reader_enabled = _global_app->a11y_schema
 761                                   ? g_settings_get_boolean (_global_app->a11y_schema, "screen-reader-enabled")
 762                                   : FALSE;
 763     }
 764
 765   if (_global_app->interface_schema)
 766     g_signal_connect (_global_app->interface_schema,
 767                       "changed::toolkit-accessibility",
 768                       G_CALLBACK (gsettings_key_changed), _global_app);
 769
 770   if (_global_app->a11y_schema)
 771     g_signal_connect (_global_app->a11y_schema,
 772                       "changed::screen-reader-enabled",
 773                       G_CALLBACK (gsettings_key_changed), _global_app);
 774
 775   init_sigterm_handling (_global_app);
 776
 777   introspection_data = g_dbus_node_info_new_for_xml (introspection_xml, NULL);
 778   g_assert (introspection_data != NULL);
 779
 780   name_owner_id = g_bus_own_name (G_BUS_TYPE_SESSION,
 781                                   "org.a11y.Bus",
 782                                   G_BUS_NAME_OWNER_FLAGS_ALLOW_REPLACEMENT,
 783                                   on_bus_acquired,
 784                                   on_name_acquired,
 785                                   on_name_lost,
 786                                   _global_app,
 787                                   NULL);
 788
 789   g_main_loop_run (_global_app->loop);
 790
 791   if (_global_app->a11y_bus_pid > 0)
 792     kill (_global_app->a11y_bus_pid, SIGTERM);
 793
 794   /* Clear the X property if our bus is gone; in the case where e.g.
 795    * GDM is launching a login on an X server it was using before,
 796    * we don't want early login processes to pick up the stale address.
 797    */
 798 #ifdef HAVE_X11
 799   {
 800     Display *display = XOpenDisplay (NULL);
 801     if (display)
 802       {
 803         Atom bus_address_atom = XInternAtom (display, "AT_SPI_BUS", False);
 804         XDeleteProperty (display,
 805                          XDefaultRootWindow (display),
 806                          bus_address_atom);
 807
 808         XFlush (display);
 809         XCloseDisplay (display);
 810       }
 811   }
 812 #endif
 813
 814   if (_global_app->a11y_launch_error_message)
 815     {
 816       g_printerr ("Failed to launch bus: %s", _global_app->a11y_launch_error_message);
 817       return 1;
 818     }
 819   return 0;
 820 }