gdbus/watch.c

   1 /*
   2  *
   3  *  D-Bus helper library
   4  *
   5  *  Copyright (C) 2004-2009  Marcel Holtmann <marcel@holtmann.org>
   6  *
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to the Free Software
  20  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  21  *
  22  */
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #include <stdio.h>
  29 #include <string.h>
  30
  31 #include <glib.h>
  32 #include <dbus/dbus.h>
  33
  34 #include "gdbus.h"
  35
  36 #define info(fmt...)
  37 #define error(fmt...)
  38 #define debug(fmt...)
  39
  40 static DBusHandlerResult name_exit_filter(DBusConnection *connection,
  41                                         DBusMessage *message, void *user_data);
  42
  43 static guint listener_id = 0;
  44 static GSList *name_listeners = NULL;
  45
  46 struct name_callback {
  47         GDBusWatchFunction conn_func;
  48         GDBusWatchFunction disc_func;
  49         void *user_data;
  50         guint id;
  51 };
  52
  53 struct name_data {
  54         DBusConnection *connection;
  55         char *name;
  56         GSList *callbacks;
  57         GSList *processed;
  58         gboolean lock;
  59 };
  60
  61 static struct name_data *name_data_find(DBusConnection *connection,
  62                                                         const char *name)
  63 {
  64         GSList *current;
  65
  66         for (current = name_listeners;
  67                         current != NULL; current = current->next) {
  68                 struct name_data *data = current->data;
  69
  70                 if (connection != data->connection)
  71                         continue;
  72
  73                 if (name == NULL || g_str_equal(name, data->name))
  74                         return data;
  75         }
  76
  77         return NULL;
  78 }
  79
  80 static struct name_callback *name_callback_find(GSList *callbacks, guint id)
  81 {
  82         GSList *current;
  83
  84         for (current = callbacks; current != NULL; current = current->next) {
  85                 struct name_callback *cb = current->data;
  86                 if (cb->id == id)
  87                         return cb;
  88         }
  89
  90         return NULL;
  91 }
  92
  93 static void name_data_call_and_free(struct name_data *data)
  94 {
  95         GSList *l;
  96
  97         for (l = data->callbacks; l != NULL; l = l->next) {
  98                 struct name_callback *cb = l->data;
  99                 if (cb->disc_func)
 100                         cb->disc_func(data->connection, cb->user_data);
 101                 g_free(cb);
 102         }
 103
 104         g_slist_free(data->callbacks);
 105         g_free(data->name);
 106         g_free(data);
 107 }
 108
 109 static void name_data_free(struct name_data *data)
 110 {
 111         GSList *l;
 112
 113         for (l = data->callbacks; l != NULL; l = l->next)
 114                 g_free(l->data);
 115
 116         g_slist_free(data->callbacks);
 117         g_free(data->name);
 118         g_free(data);
 119 }
 120
 121 static int name_data_add(DBusConnection *connection, const char *name,
 122                                                 GDBusWatchFunction connect,
 123                                                 GDBusWatchFunction disconnect,
 124                                                 void *user_data, guint id)
 125 {
 126         int first = 1;
 127         struct name_data *data = NULL;
 128         struct name_callback *cb = NULL;
 129
 130         cb = g_new(struct name_callback, 1);
 131
 132         cb->conn_func = connect;
 133         cb->disc_func = disconnect;
 134         cb->user_data = user_data;
 135         cb->id = id;
 136
 137         data = name_data_find(connection, name);
 138         if (data) {
 139                 first = 0;
 140                 goto done;
 141         }
 142
 143         data = g_new0(struct name_data, 1);
 144
 145         data->connection = connection;
 146         data->name = g_strdup(name);
 147
 148         name_listeners = g_slist_append(name_listeners, data);
 149
 150 done:
 151         if (data->lock)
 152                 data->processed = g_slist_append(data->processed, cb);
 153         else
 154                 data->callbacks = g_slist_append(data->callbacks, cb);
 155
 156         return first;
 157 }
 158
 159 static void name_data_remove(DBusConnection *connection,
 160                                         const char *name, guint id)
 161 {
 162         struct name_data *data;
 163         struct name_callback *cb = NULL;
 164
 165         data = name_data_find(connection, name);
 166         if (!data)
 167                 return;
 168
 169         cb = name_callback_find(data->callbacks, id);
 170         if (cb) {
 171                 data->callbacks = g_slist_remove(data->callbacks, cb);
 172                 g_free(cb);
 173         }
 174
 175         if (data->callbacks)
 176                 return;
 177
 178         name_listeners = g_slist_remove(name_listeners, data);
 179         name_data_free(data);
 180
 181         /* Remove filter if there are no listeners left for the connection */
 182         data = name_data_find(connection, NULL);
 183         if (!data)
 184                 dbus_connection_remove_filter(connection,
 185                                                 name_exit_filter,
 186                                                 NULL);
 187 }
 188
 189 static gboolean add_match(DBusConnection *connection, const char *name)
 190 {
 191         DBusError err;
 192         char match_string[128];
 193
 194         snprintf(match_string, sizeof(match_string),
 195                         "interface=%s,member=NameOwnerChanged,arg0=%s",
 196                         DBUS_INTERFACE_DBUS, name);
 197
 198         dbus_error_init(&err);
 199
 200         dbus_bus_add_match(connection, match_string, &err);
 201
 202         if (dbus_error_is_set(&err)) {
 203                 error("Adding match rule \"%s\" failed: %s", match_string,
 204                                 err.message);
 205                 dbus_error_free(&err);
 206                 return FALSE;
 207         }
 208
 209         return TRUE;
 210 }
 211
 212 static gboolean remove_match(DBusConnection *connection, const char *name)
 213 {
 214         DBusError err;
 215         char match_string[128];
 216
 217         snprintf(match_string, sizeof(match_string),
 218                         "interface=%s,member=NameOwnerChanged,arg0=%s",
 219                         DBUS_INTERFACE_DBUS, name);
 220
 221         dbus_error_init(&err);
 222
 223         dbus_bus_remove_match(connection, match_string, &err);
 224
 225         if (dbus_error_is_set(&err)) {
 226                 error("Removing owner match rule for %s failed: %s",
 227                                 name, err.message);
 228                 dbus_error_free(&err);
 229                 return FALSE;
 230         }
 231
 232         return TRUE;
 233 }
 234
 235 static DBusHandlerResult name_exit_filter(DBusConnection *connection,
 236                                         DBusMessage *message, void *user_data)
 237 {
 238         struct name_data *data;
 239         struct name_callback *cb;
 240         char *name, *old, *new;
 241
 242         if (!dbus_message_is_signal(message, DBUS_INTERFACE_DBUS,
 243                                                         "NameOwnerChanged"))
 244                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 245
 246         if (!dbus_message_get_args(message, NULL,
 247                                 DBUS_TYPE_STRING, &name,
 248                                 DBUS_TYPE_STRING, &old,
 249                                 DBUS_TYPE_STRING, &new,
 250                                 DBUS_TYPE_INVALID)) {
 251                 error("Invalid arguments for NameOwnerChanged signal");
 252                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 253         }
 254
 255         data = name_data_find(connection, name);
 256         if (!data) {
 257                 error("Got NameOwnerChanged signal for %s which has no listeners", name);
 258                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 259         }
 260
 261         data->lock = TRUE;
 262
 263         while (data->callbacks) {
 264                 cb = data->callbacks->data;
 265
 266                 if (*new == '\0') {
 267                         if (cb->disc_func)
 268                                 cb->disc_func(connection, cb->user_data);
 269                 } else {
 270                         if (cb->conn_func)
 271                                 cb->conn_func(connection, cb->user_data);
 272                 }
 273
 274                 /* Check if the watch was removed/freed by the callback
 275                  * function */
 276                 if (!g_slist_find(data->callbacks, cb))
 277                         continue;
 278
 279                 data->callbacks = g_slist_remove(data->callbacks, cb);
 280
 281                 if (!cb->conn_func || !cb->disc_func) {
 282                         g_free(cb);
 283                         continue;
 284                 }
 285
 286                 data->processed = g_slist_append(data->processed, cb);
 287         }
 288
 289         data->callbacks = data->processed;
 290         data->processed = NULL;
 291         data->lock = FALSE;
 292
 293         if (data->callbacks)
 294                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 295
 296         name_listeners = g_slist_remove(name_listeners, data);
 297         name_data_free(data);
 298
 299         /* Remove filter if there no listener left for the connection */
 300         data = name_data_find(connection, NULL);
 301         if (!data)
 302                 dbus_connection_remove_filter(connection, name_exit_filter,
 303                                                 NULL);
 304
 305         remove_match(connection, name);
 306
 307         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 308 }
 309
 310 struct service_data {
 311         DBusConnection *conn;
 312         GDBusWatchFunction conn_func;
 313         void *user_data;
 314 };
 315
 316 static void service_reply(DBusPendingCall *call, void *user_data)
 317 {
 318         struct service_data *data = user_data;
 319         DBusMessage *reply;
 320         DBusError error;
 321         dbus_bool_t has_owner;
 322
 323         reply = dbus_pending_call_steal_reply(call);
 324         if (reply == NULL)
 325                 return;
 326
 327         dbus_error_init(&error);
 328
 329         if (dbus_message_get_args(reply, &error,
 330                                         DBUS_TYPE_BOOLEAN, &has_owner,
 331                                                 DBUS_TYPE_INVALID) == FALSE) {
 332                 if (dbus_error_is_set(&error) == TRUE) {
 333                         error("%s", error.message);
 334                         dbus_error_free(&error);
 335                 } else {
 336                         error("Wrong arguments for NameHasOwner reply");
 337                 }
 338                 goto done;
 339         }
 340
 341         if (has_owner && data->conn_func)
 342                 data->conn_func(data->conn, data->user_data);
 343
 344 done:
 345         dbus_message_unref(reply);
 346 }
 347
 348 static void check_service(DBusConnection *connection, const char *name,
 349                                 GDBusWatchFunction connect, void *user_data)
 350 {
 351         DBusMessage *message;
 352         DBusPendingCall *call;
 353         struct service_data *data;
 354
 355         data = g_try_malloc0(sizeof(*data));
 356         if (data == NULL) {
 357                 error("Can't allocate data structure");
 358                 return;
 359         }
 360
 361         data->conn = connection;
 362         data->conn_func = connect;
 363         data->user_data = user_data;
 364
 365         message = dbus_message_new_method_call(DBUS_SERVICE_DBUS,
 366                         DBUS_PATH_DBUS, DBUS_INTERFACE_DBUS, "NameHasOwner");
 367         if (message == NULL) {
 368                 error("Can't allocate new message");
 369                 g_free(data);
 370                 return;
 371         }
 372
 373         dbus_message_append_args(message, DBUS_TYPE_STRING, &name,
 374                                                         DBUS_TYPE_INVALID);
 375
 376         if (dbus_connection_send_with_reply(connection, message,
 377                                                         &call, -1) == FALSE) {
 378                 error("Failed to execute method call");
 379                 g_free(data);
 380                 goto done;
 381         }
 382
 383         if (call == NULL) {
 384                 error("D-Bus connection not available");
 385                 g_free(data);
 386                 goto done;
 387         }
 388
 389         dbus_pending_call_set_notify(call, service_reply, data, NULL);
 390
 391 done:
 392         dbus_message_unref(message);
 393 }
 394
 395 guint g_dbus_add_service_watch(DBusConnection *connection, const char *name,
 396                                 GDBusWatchFunction connect,
 397                                 GDBusWatchFunction disconnect,
 398                                 void *user_data, GDBusDestroyFunction destroy)
 399 {
 400         int first;
 401
 402         if (!name_data_find(connection, NULL)) {
 403                 if (!dbus_connection_add_filter(connection,
 404                                         name_exit_filter, NULL, NULL)) {
 405                         error("dbus_connection_add_filter() failed");
 406                         return 0;
 407                 }
 408         }
 409
 410         listener_id++;
 411         first = name_data_add(connection, name, connect, disconnect,
 412                                                 user_data, listener_id);
 413         /* The filter is already added if this is not the first callback
 414          * registration for the name */
 415         if (!first)
 416                 goto done;
 417
 418         if (name) {
 419                 debug("name_listener_add(%s)", name);
 420
 421                 if (!add_match(connection, name)) {
 422                         name_data_remove(connection, name, listener_id);
 423                         return 0;
 424                 }
 425         }
 426
 427 done:
 428         if (connect)
 429                 check_service(connection, name, connect, user_data);
 430
 431         return listener_id;
 432 }
 433
 434 guint g_dbus_add_disconnect_watch(DBusConnection *connection, const char *name,
 435                                 GDBusWatchFunction func,
 436                                 void *user_data, GDBusDestroyFunction destroy)
 437 {
 438         return g_dbus_add_service_watch(connection, name, NULL, func,
 439                                                         user_data, destroy);
 440 }
 441
 442 guint g_dbus_add_signal_watch(DBusConnection *connection,
 443                                 const char *rule, GDBusSignalFunction function,
 444                                 void *user_data, GDBusDestroyFunction destroy)
 445 {
 446         return 0;
 447 }
 448
 449 gboolean g_dbus_remove_watch(DBusConnection *connection, guint id)
 450 {
 451         struct name_data *data;
 452         struct name_callback *cb;
 453         GSList *ldata, *lcb;
 454
 455         if (id == 0)
 456                 return FALSE;
 457
 458         for (ldata = name_listeners; ldata; ldata = ldata->next) {
 459                 data = ldata->data;
 460                 for (lcb = data->callbacks; lcb; lcb = lcb->next) {
 461                         cb = lcb->data;
 462                         if (cb->id == id)
 463                                 goto remove;
 464                 }
 465                 for (lcb = data->processed; lcb; lcb = lcb->next) {
 466                         cb = lcb->data;
 467                         if (cb->id == id)
 468                                 goto remove;
 469                 }
 470         }
 471
 472         return FALSE;
 473
 474 remove:
 475         data->callbacks = g_slist_remove(data->callbacks, cb);
 476         data->processed = g_slist_remove(data->processed, cb);
 477         g_free(cb);
 478
 479         /* Don't remove the filter if other callbacks exist or data is lock
 480          * processing callbacks */
 481         if (data->callbacks || data->lock)
 482                 return TRUE;
 483
 484         if (data->name) {
 485                 if (!remove_match(data->connection, data->name))
 486                         return FALSE;
 487         }
 488
 489         name_listeners = g_slist_remove(name_listeners, data);
 490         name_data_free(data);
 491
 492         /* Remove filter if there are no listeners left for the connection */
 493         data = name_data_find(connection, NULL);
 494         if (!data)
 495                 dbus_connection_remove_filter(connection, name_exit_filter,
 496                                                 NULL);
 497
 498         return TRUE;
 499 }
 500
 501 void g_dbus_remove_all_watches(DBusConnection *connection)
 502 {
 503         struct name_data *data;
 504
 505         while ((data = name_data_find(connection, NULL))) {
 506                 name_listeners = g_slist_remove(name_listeners, data);
 507                 name_data_call_and_free(data);
 508         }
 509
 510         dbus_connection_remove_filter(connection, name_exit_filter, NULL);
 511 }