gdbus/watch.c

   1 /*
   2  *
   3  *  D-Bus helper library
   4  *
   5  *  Copyright (C) 2004-2010  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 message_filter(DBusConnection *connection,
  41                                         DBusMessage *message, void *user_data);
  42
  43 static guint listener_id = 0;
  44 static GSList *listeners = NULL;
  45
  46 struct filter_callback {
  47         GDBusWatchFunction conn_func;
  48         GDBusWatchFunction disc_func;
  49         GDBusSignalFunction signal_func;
  50         GDBusDestroyFunction destroy_func;
  51         void *user_data;
  52         guint id;
  53 };
  54
  55 struct filter_data {
  56         DBusConnection *connection;
  57         DBusHandleMessageFunction handle_func;
  58         char *sender;
  59         char *path;
  60         char *interface;
  61         char *member;
  62         char *argument;
  63         GSList *callbacks;
  64         GSList *processed;
  65         gboolean lock;
  66         gboolean registered;
  67 };
  68
  69 static struct filter_data *filter_data_find(DBusConnection *connection,
  70                                                         const char *sender,
  71                                                         const char *path,
  72                                                         const char *interface,
  73                                                         const char *member,
  74                                                         const char *argument)
  75 {
  76         GSList *current;
  77
  78         for (current = listeners;
  79                         current != NULL; current = current->next) {
  80                 struct filter_data *data = current->data;
  81
  82                 if (connection != data->connection)
  83                         continue;
  84
  85                 if (sender && data->sender &&
  86                                 g_str_equal(sender, data->sender) == FALSE)
  87                         continue;
  88
  89                 if (path && data->path &&
  90                                 g_str_equal(path, data->path) == FALSE)
  91                         continue;
  92
  93                 if (interface && data->interface &&
  94                                 g_str_equal(interface, data->interface) == FALSE)
  95                         continue;
  96
  97                 if (member && data->member &&
  98                                 g_str_equal(member, data->member) == FALSE)
  99                         continue;
 100
 101                 if (argument && data->argument &&
 102                                 g_str_equal(argument, data->argument) == FALSE)
 103                         continue;
 104
 105                 return data;
 106         }
 107
 108         return NULL;
 109 }
 110
 111 static void format_rule(struct filter_data *data, char *rule, size_t size)
 112 {
 113         int offset;
 114
 115         offset = snprintf(rule, size, "type='signal'");
 116
 117         if (data->sender)
 118                 offset += snprintf(rule + offset, size - offset,
 119                                 ",sender='%s'", data->sender);
 120         if (data->path)
 121                 offset += snprintf(rule + offset, size - offset,
 122                                 ",path='%s'", data->path);
 123         if (data->interface)
 124                 offset += snprintf(rule + offset, size - offset,
 125                                 ",interface='%s'", data->interface);
 126         if (data->member)
 127                 offset += snprintf(rule + offset, size - offset,
 128                                 ",member='%s'", data->member);
 129         if (data->argument)
 130                 snprintf(rule + offset, size - offset,
 131                                 ",arg0='%s'", data->argument);
 132 }
 133
 134 static gboolean add_match(struct filter_data *data,
 135                                 DBusHandleMessageFunction filter)
 136 {
 137         DBusError err;
 138         char rule[DBUS_MAXIMUM_MATCH_RULE_LENGTH];
 139
 140         format_rule(data, rule, sizeof(rule));
 141         dbus_error_init(&err);
 142
 143         dbus_bus_add_match(data->connection, rule, &err);
 144         if (dbus_error_is_set(&err)) {
 145                 error("Adding match rule \"%s\" failed: %s", rule,
 146                                 err.message);
 147                 dbus_error_free(&err);
 148                 return FALSE;
 149         }
 150
 151         data->handle_func = filter;
 152         data->registered = TRUE;
 153
 154         return TRUE;
 155 }
 156
 157 static gboolean remove_match(struct filter_data *data)
 158 {
 159         DBusError err;
 160         char rule[DBUS_MAXIMUM_MATCH_RULE_LENGTH];
 161
 162         format_rule(data, rule, sizeof(rule));
 163
 164         dbus_error_init(&err);
 165
 166         dbus_bus_remove_match(data->connection, rule, &err);
 167         if (dbus_error_is_set(&err)) {
 168                 error("Removing owner match rule for %s failed: %s",
 169                                 rule, err.message);
 170                 dbus_error_free(&err);
 171                 return FALSE;
 172         }
 173
 174         return TRUE;
 175 }
 176
 177 static struct filter_data *filter_data_get(DBusConnection *connection,
 178                                         DBusHandleMessageFunction filter,
 179                                         const char *sender,
 180                                         const char *path,
 181                                         const char *interface,
 182                                         const char *member,
 183                                         const char *argument)
 184 {
 185         struct filter_data *data;
 186
 187         if (!filter_data_find(connection, NULL, NULL, NULL, NULL, NULL)) {
 188                 if (!dbus_connection_add_filter(connection,
 189                                         message_filter, NULL, NULL)) {
 190                         error("dbus_connection_add_filter() failed");
 191                         return NULL;
 192                 }
 193         }
 194
 195         data = filter_data_find(connection, sender, path, interface, member,
 196                                         argument);
 197         if (data)
 198                 return data;
 199
 200         data = g_new0(struct filter_data, 1);
 201
 202         data->connection = dbus_connection_ref(connection);
 203         data->sender = g_strdup(sender);
 204         data->path = g_strdup(path);
 205         data->interface = g_strdup(interface);
 206         data->member = g_strdup(member);
 207         data->argument = g_strdup(argument);
 208
 209         if (!add_match(data, filter)) {
 210                 g_free(data);
 211                 return NULL;
 212         }
 213
 214         listeners = g_slist_append(listeners, data);
 215
 216         return data;
 217 }
 218
 219 static struct filter_callback *filter_data_find_callback(
 220                                                 struct filter_data *data,
 221                                                 guint id)
 222 {
 223         GSList *l;
 224
 225         for (l = data->callbacks; l; l = l->next) {
 226                 struct filter_callback *cb = l->data;
 227                 if (cb->id == id)
 228                         return cb;
 229         }
 230         for (l = data->processed; l; l = l->next) {
 231                 struct filter_callback *cb = l->data;
 232                 if (cb->id == id)
 233                         return cb;
 234         }
 235
 236         return NULL;
 237 }
 238
 239 static void filter_data_free(struct filter_data *data)
 240 {
 241         GSList *l;
 242
 243         for (l = data->callbacks; l != NULL; l = l->next)
 244                 g_free(l->data);
 245
 246         g_slist_free(data->callbacks);
 247         g_free(data->sender);
 248         g_free(data->path);
 249         g_free(data->interface);
 250         g_free(data->member);
 251         g_free(data->argument);
 252         dbus_connection_unref(data->connection);
 253         g_free(data);
 254 }
 255
 256 static void filter_data_call_and_free(struct filter_data *data)
 257 {
 258         GSList *l;
 259
 260         for (l = data->callbacks; l != NULL; l = l->next) {
 261                 struct filter_callback *cb = l->data;
 262                 if (cb->disc_func)
 263                         cb->disc_func(data->connection, cb->user_data);
 264                 if (cb->destroy_func)
 265                         cb->destroy_func(cb->user_data);
 266                 g_free(cb);
 267         }
 268
 269         filter_data_free(data);
 270 }
 271
 272 static struct filter_callback *filter_data_add_callback(
 273                                                 struct filter_data *data,
 274                                                 GDBusWatchFunction connect,
 275                                                 GDBusWatchFunction disconnect,
 276                                                 GDBusSignalFunction signal,
 277                                                 GDBusDestroyFunction destroy,
 278                                                 void *user_data)
 279 {
 280         struct filter_callback *cb = NULL;
 281
 282         cb = g_new(struct filter_callback, 1);
 283
 284         cb->conn_func = connect;
 285         cb->disc_func = disconnect;
 286         cb->signal_func = signal;
 287         cb->destroy_func = destroy;
 288         cb->user_data = user_data;
 289         cb->id = ++listener_id;
 290
 291         if (data->lock)
 292                 data->processed = g_slist_append(data->processed, cb);
 293         else
 294                 data->callbacks = g_slist_append(data->callbacks, cb);
 295
 296         return cb;
 297 }
 298
 299 static gboolean filter_data_remove_callback(struct filter_data *data,
 300                                                 struct filter_callback *cb)
 301 {
 302         DBusConnection *connection;
 303
 304         data->callbacks = g_slist_remove(data->callbacks, cb);
 305         data->processed = g_slist_remove(data->processed, cb);
 306
 307         if (cb->destroy_func)
 308                 cb->destroy_func(cb->user_data);
 309
 310         g_free(cb);
 311
 312         /* Don't remove the filter if other callbacks exist or data is lock
 313          * processing callbacks */
 314         if (data->callbacks || data->lock)
 315                 return TRUE;
 316
 317         if (data->registered && !remove_match(data))
 318                 return FALSE;
 319
 320         connection = dbus_connection_ref(data->connection);
 321         listeners = g_slist_remove(listeners, data);
 322         filter_data_free(data);
 323
 324         /* Remove filter if there are no listeners left for the connection */
 325         data = filter_data_find(connection, NULL, NULL, NULL, NULL, NULL);
 326         if (!data)
 327                 dbus_connection_remove_filter(connection, message_filter,
 328                                                 NULL);
 329
 330         dbus_connection_unref(connection);
 331
 332         return TRUE;
 333 }
 334
 335 static DBusHandlerResult signal_filter(DBusConnection *connection,
 336                                         DBusMessage *message, void *user_data)
 337 {
 338         struct filter_data *data = user_data;
 339         struct filter_callback *cb;
 340
 341         while (data->callbacks) {
 342                 cb = data->callbacks->data;
 343
 344                 if (cb->signal_func && !cb->signal_func(connection, message,
 345                                                         cb->user_data)) {
 346                         filter_data_remove_callback(data, cb);
 347                         continue;
 348                 }
 349
 350                 /* Check if the watch was removed/freed by the callback
 351                  * function */
 352                 if (!g_slist_find(data->callbacks, cb))
 353                         continue;
 354
 355                 data->callbacks = g_slist_remove(data->callbacks, cb);
 356                 data->processed = g_slist_append(data->processed, cb);
 357         }
 358
 359         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 360 }
 361
 362 static DBusHandlerResult service_filter(DBusConnection *connection,
 363                                         DBusMessage *message, void *user_data)
 364 {
 365         struct filter_data *data = user_data;
 366         struct filter_callback *cb;
 367         char *name, *old, *new;
 368
 369         if (!dbus_message_get_args(message, NULL,
 370                                 DBUS_TYPE_STRING, &name,
 371                                 DBUS_TYPE_STRING, &old,
 372                                 DBUS_TYPE_STRING, &new,
 373                                 DBUS_TYPE_INVALID)) {
 374                 error("Invalid arguments for NameOwnerChanged signal");
 375                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 376         }
 377
 378         while (data->callbacks) {
 379                 cb = data->callbacks->data;
 380
 381                 if (*new == '\0') {
 382                         if (cb->disc_func)
 383                                 cb->disc_func(connection, cb->user_data);
 384                 } else {
 385                         if (cb->conn_func)
 386                                 cb->conn_func(connection, cb->user_data);
 387                 }
 388
 389                 /* Check if the watch was removed/freed by the callback
 390                  * function */
 391                 if (!g_slist_find(data->callbacks, cb))
 392                         continue;
 393
 394                 data->callbacks = g_slist_remove(data->callbacks, cb);
 395
 396                 if (!cb->conn_func || !cb->disc_func) {
 397                         g_free(cb);
 398                         continue;
 399                 }
 400
 401                 data->processed = g_slist_append(data->processed, cb);
 402         }
 403
 404         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 405 }
 406
 407
 408 static DBusHandlerResult message_filter(DBusConnection *connection,
 409                                         DBusMessage *message, void *user_data)
 410 {
 411         struct filter_data *data;
 412         const char *sender, *path, *iface, *member, *arg = NULL;
 413
 414         /* Only filter signals */
 415         if (dbus_message_get_type(message) != DBUS_MESSAGE_TYPE_SIGNAL)
 416                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 417
 418         sender = dbus_message_get_sender(message);
 419         path = dbus_message_get_path(message);
 420         iface = dbus_message_get_interface(message);
 421         member = dbus_message_get_member(message);
 422         dbus_message_get_args(message, NULL, DBUS_TYPE_STRING, &arg, DBUS_TYPE_INVALID);
 423
 424         data = filter_data_find(connection, sender, path, iface, member, arg);
 425         if (!data) {
 426                 error("Got %s.%s signal which has no listeners", iface, member);
 427                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 428         }
 429
 430         if (data->handle_func) {
 431                 data->lock = TRUE;
 432
 433                 data->handle_func(connection, message, data);
 434
 435                 data->callbacks = data->processed;
 436                 data->processed = NULL;
 437                 data->lock = FALSE;
 438         }
 439
 440         if (data->callbacks)
 441                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 442
 443         remove_match(data);
 444
 445         listeners = g_slist_remove(listeners, data);
 446         filter_data_free(data);
 447
 448         /* Remove filter if there no listener left for the connection */
 449         data = filter_data_find(connection, NULL, NULL, NULL, NULL, NULL);
 450         if (!data)
 451                 dbus_connection_remove_filter(connection, message_filter,
 452                                                 NULL);
 453
 454         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 455 }
 456
 457 struct service_data {
 458         DBusConnection *conn;
 459         GDBusWatchFunction conn_func;
 460         void *user_data;
 461 };
 462
 463 static void service_reply(DBusPendingCall *call, void *user_data)
 464 {
 465         struct service_data *data = user_data;
 466         DBusMessage *reply;
 467         DBusError error;
 468         dbus_bool_t has_owner;
 469
 470         reply = dbus_pending_call_steal_reply(call);
 471         if (reply == NULL)
 472                 return;
 473
 474         dbus_error_init(&error);
 475
 476         if (dbus_message_get_args(reply, &error,
 477                                         DBUS_TYPE_BOOLEAN, &has_owner,
 478                                                 DBUS_TYPE_INVALID) == FALSE) {
 479                 if (dbus_error_is_set(&error) == TRUE) {
 480                         error("%s", error.message);
 481                         dbus_error_free(&error);
 482                 } else {
 483                         error("Wrong arguments for NameHasOwner reply");
 484                 }
 485                 goto done;
 486         }
 487
 488         if (has_owner && data->conn_func)
 489                 data->conn_func(data->conn, data->user_data);
 490
 491 done:
 492         dbus_message_unref(reply);
 493 }
 494
 495 static void check_service(DBusConnection *connection, const char *name,
 496                                 GDBusWatchFunction connect, void *user_data)
 497 {
 498         DBusMessage *message;
 499         DBusPendingCall *call;
 500         struct service_data *data;
 501
 502         data = g_try_malloc0(sizeof(*data));
 503         if (data == NULL) {
 504                 error("Can't allocate data structure");
 505                 return;
 506         }
 507
 508         data->conn = connection;
 509         data->conn_func = connect;
 510         data->user_data = user_data;
 511
 512         message = dbus_message_new_method_call(DBUS_SERVICE_DBUS,
 513                         DBUS_PATH_DBUS, DBUS_INTERFACE_DBUS, "NameHasOwner");
 514         if (message == NULL) {
 515                 error("Can't allocate new message");
 516                 g_free(data);
 517                 return;
 518         }
 519
 520         dbus_message_append_args(message, DBUS_TYPE_STRING, &name,
 521                                                         DBUS_TYPE_INVALID);
 522
 523         if (dbus_connection_send_with_reply(connection, message,
 524                                                         &call, -1) == FALSE) {
 525                 error("Failed to execute method call");
 526                 g_free(data);
 527                 goto done;
 528         }
 529
 530         if (call == NULL) {
 531                 error("D-Bus connection not available");
 532                 g_free(data);
 533                 goto done;
 534         }
 535
 536         dbus_pending_call_set_notify(call, service_reply, data, g_free);
 537
 538         dbus_pending_call_unref(call);
 539
 540 done:
 541         dbus_message_unref(message);
 542 }
 543
 544 guint g_dbus_add_service_watch(DBusConnection *connection, const char *name,
 545                                 GDBusWatchFunction connect,
 546                                 GDBusWatchFunction disconnect,
 547                                 void *user_data, GDBusDestroyFunction destroy)
 548 {
 549         struct filter_data *data;
 550         struct filter_callback *cb;
 551
 552         if (!name)
 553                 return 0;
 554
 555         data = filter_data_get(connection, service_filter, NULL, NULL,
 556                                 DBUS_INTERFACE_DBUS, "NameOwnerChanged",
 557                                 name);
 558         if (!data)
 559                 return 0;
 560
 561         cb = filter_data_add_callback(data, connect, disconnect, NULL, NULL,
 562                                         user_data);
 563         if (!cb)
 564                 return 0;
 565
 566         if (connect)
 567                 check_service(connection, name, connect, user_data);
 568
 569         return cb->id;
 570 }
 571
 572 guint g_dbus_add_disconnect_watch(DBusConnection *connection, const char *name,
 573                                 GDBusWatchFunction func,
 574                                 void *user_data, GDBusDestroyFunction destroy)
 575 {
 576         return g_dbus_add_service_watch(connection, name, NULL, func,
 577                                                         user_data, destroy);
 578 }
 579
 580 guint g_dbus_add_signal_watch(DBusConnection *connection,
 581                                 const char *sender, const char *path,
 582                                 const char *interface, const char *member,
 583                                 GDBusSignalFunction function, void *user_data,
 584                                 GDBusDestroyFunction destroy)
 585 {
 586         struct filter_data *data;
 587         struct filter_callback *cb;
 588
 589         data = filter_data_get(connection, signal_filter, sender, path,
 590                                 interface, member, NULL);
 591         if (!data)
 592                 return 0;
 593
 594         cb = filter_data_add_callback(data, NULL, NULL, function, destroy,
 595                                         user_data);
 596         if (!cb)
 597                 return 0;
 598
 599         return cb->id;
 600 }
 601
 602 gboolean g_dbus_remove_watch(DBusConnection *connection, guint id)
 603 {
 604         struct filter_data *data;
 605         struct filter_callback *cb;
 606         GSList *ldata;
 607
 608         if (id == 0)
 609                 return FALSE;
 610
 611         for (ldata = listeners; ldata; ldata = ldata->next) {
 612                 data = ldata->data;
 613
 614                 cb = filter_data_find_callback(data, id);
 615                 if (cb) {
 616                         filter_data_remove_callback(data, cb);
 617                         return TRUE;
 618                 }
 619         }
 620
 621         return FALSE;
 622 }
 623
 624 void g_dbus_remove_all_watches(DBusConnection *connection)
 625 {
 626         struct filter_data *data;
 627
 628         while ((data = filter_data_find(connection, NULL, NULL, NULL, NULL, NULL))) {
 629                 listeners = g_slist_remove(listeners, data);
 630                 filter_data_call_and_free(data);
 631         }
 632
 633         dbus_connection_remove_filter(connection, message_filter, NULL);
 634 }