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 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         data->callbacks = g_slist_remove(data->callbacks, cb);
 303         data->processed = g_slist_remove(data->processed, cb);
 304
 305         if (cb->destroy_func)
 306                 cb->destroy_func(cb->user_data);
 307
 308         g_free(cb);
 309
 310         /* Don't remove the filter if other callbacks exist or data is lock
 311          * processing callbacks */
 312         if (data->callbacks || data->lock)
 313                 return TRUE;
 314
 315         if (data->registered && !remove_match(data))
 316                 return FALSE;
 317
 318         /* Remove filter if there are no listeners left for the connection */
 319         data = filter_data_find(data->connection, NULL, NULL, NULL, NULL,
 320                                         NULL);
 321         if (!data)
 322                 dbus_connection_remove_filter(data->connection, message_filter,
 323                                                 NULL);
 324
 325         listeners = g_slist_remove(listeners, data);
 326         filter_data_free(data);
 327
 328         return TRUE;
 329 }
 330
 331 static DBusHandlerResult signal_filter(DBusConnection *connection,
 332                                         DBusMessage *message, void *user_data)
 333 {
 334         struct filter_data *data = user_data;
 335         struct filter_callback *cb;
 336
 337         while (data->callbacks) {
 338                 cb = data->callbacks->data;
 339
 340                 if (cb->signal_func && !cb->signal_func(connection, message,
 341                                                         cb->user_data)) {
 342                         filter_data_remove_callback(data, cb);
 343                         continue;
 344                 }
 345
 346                 /* Check if the watch was removed/freed by the callback
 347                  * function */
 348                 if (!g_slist_find(data->callbacks, cb))
 349                         continue;
 350
 351                 data->callbacks = g_slist_remove(data->callbacks, cb);
 352                 data->processed = g_slist_append(data->processed, cb);
 353         }
 354
 355         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 356 }
 357
 358 static DBusHandlerResult service_filter(DBusConnection *connection,
 359                                         DBusMessage *message, void *user_data)
 360 {
 361         struct filter_data *data = user_data;
 362         struct filter_callback *cb;
 363         char *name, *old, *new;
 364
 365         if (!dbus_message_get_args(message, NULL,
 366                                 DBUS_TYPE_STRING, &name,
 367                                 DBUS_TYPE_STRING, &old,
 368                                 DBUS_TYPE_STRING, &new,
 369                                 DBUS_TYPE_INVALID)) {
 370                 error("Invalid arguments for NameOwnerChanged signal");
 371                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 372         }
 373
 374         while (data->callbacks) {
 375                 cb = data->callbacks->data;
 376
 377                 if (*new == '\0') {
 378                         if (cb->disc_func)
 379                                 cb->disc_func(connection, cb->user_data);
 380                 } else {
 381                         if (cb->conn_func)
 382                                 cb->conn_func(connection, cb->user_data);
 383                 }
 384
 385                 /* Check if the watch was removed/freed by the callback
 386                  * function */
 387                 if (!g_slist_find(data->callbacks, cb))
 388                         continue;
 389
 390                 data->callbacks = g_slist_remove(data->callbacks, cb);
 391
 392                 if (!cb->conn_func || !cb->disc_func) {
 393                         g_free(cb);
 394                         continue;
 395                 }
 396
 397                 data->processed = g_slist_append(data->processed, cb);
 398         }
 399
 400         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 401 }
 402
 403
 404 static DBusHandlerResult message_filter(DBusConnection *connection,
 405                                         DBusMessage *message, void *user_data)
 406 {
 407         struct filter_data *data;
 408         const char *sender, *path, *iface, *member, *arg = NULL;
 409
 410         /* Only filter signals */
 411         if (dbus_message_get_type(message) != DBUS_MESSAGE_TYPE_SIGNAL)
 412                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 413
 414         sender = dbus_message_get_sender(message);
 415         path = dbus_message_get_path(message);
 416         iface = dbus_message_get_interface(message);
 417         member = dbus_message_get_member(message);
 418         dbus_message_get_args(message, NULL, DBUS_TYPE_STRING, &arg, DBUS_TYPE_INVALID);
 419
 420         data = filter_data_find(connection, sender, path, iface, member, arg);
 421         if (!data) {
 422                 error("Got %s.%s signal which has no listeners", iface, member);
 423                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 424         }
 425
 426         if (data->handle_func) {
 427                 data->lock = TRUE;
 428
 429                 data->handle_func(connection, message, data);
 430
 431                 data->callbacks = data->processed;
 432                 data->processed = NULL;
 433                 data->lock = FALSE;
 434         }
 435
 436         if (data->callbacks)
 437                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 438
 439         remove_match(data);
 440
 441         listeners = g_slist_remove(listeners, data);
 442         filter_data_free(data);
 443
 444         /* Remove filter if there no listener left for the connection */
 445         data = filter_data_find(connection, NULL, NULL, NULL, NULL, NULL);
 446         if (!data)
 447                 dbus_connection_remove_filter(connection, message_filter,
 448                                                 NULL);
 449
 450         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 451 }
 452
 453 struct service_data {
 454         DBusConnection *conn;
 455         GDBusWatchFunction conn_func;
 456         void *user_data;
 457 };
 458
 459 static void service_reply(DBusPendingCall *call, void *user_data)
 460 {
 461         struct service_data *data = user_data;
 462         DBusMessage *reply;
 463         DBusError error;
 464         dbus_bool_t has_owner;
 465
 466         reply = dbus_pending_call_steal_reply(call);
 467         if (reply == NULL)
 468                 return;
 469
 470         dbus_error_init(&error);
 471
 472         if (dbus_message_get_args(reply, &error,
 473                                         DBUS_TYPE_BOOLEAN, &has_owner,
 474                                                 DBUS_TYPE_INVALID) == FALSE) {
 475                 if (dbus_error_is_set(&error) == TRUE) {
 476                         error("%s", error.message);
 477                         dbus_error_free(&error);
 478                 } else {
 479                         error("Wrong arguments for NameHasOwner reply");
 480                 }
 481                 goto done;
 482         }
 483
 484         if (has_owner && data->conn_func)
 485                 data->conn_func(data->conn, data->user_data);
 486
 487 done:
 488         dbus_message_unref(reply);
 489 }
 490
 491 static void check_service(DBusConnection *connection, const char *name,
 492                                 GDBusWatchFunction connect, void *user_data)
 493 {
 494         DBusMessage *message;
 495         DBusPendingCall *call;
 496         struct service_data *data;
 497
 498         data = g_try_malloc0(sizeof(*data));
 499         if (data == NULL) {
 500                 error("Can't allocate data structure");
 501                 return;
 502         }
 503
 504         data->conn = connection;
 505         data->conn_func = connect;
 506         data->user_data = user_data;
 507
 508         message = dbus_message_new_method_call(DBUS_SERVICE_DBUS,
 509                         DBUS_PATH_DBUS, DBUS_INTERFACE_DBUS, "NameHasOwner");
 510         if (message == NULL) {
 511                 error("Can't allocate new message");
 512                 g_free(data);
 513                 return;
 514         }
 515
 516         dbus_message_append_args(message, DBUS_TYPE_STRING, &name,
 517                                                         DBUS_TYPE_INVALID);
 518
 519         if (dbus_connection_send_with_reply(connection, message,
 520                                                         &call, -1) == FALSE) {
 521                 error("Failed to execute method call");
 522                 g_free(data);
 523                 goto done;
 524         }
 525
 526         if (call == NULL) {
 527                 error("D-Bus connection not available");
 528                 g_free(data);
 529                 goto done;
 530         }
 531
 532         dbus_pending_call_set_notify(call, service_reply, data, NULL);
 533
 534 done:
 535         dbus_message_unref(message);
 536 }
 537
 538 guint g_dbus_add_service_watch(DBusConnection *connection, const char *name,
 539                                 GDBusWatchFunction connect,
 540                                 GDBusWatchFunction disconnect,
 541                                 void *user_data, GDBusDestroyFunction destroy)
 542 {
 543         struct filter_data *data;
 544         struct filter_callback *cb;
 545
 546         if (!name)
 547                 return 0;
 548
 549         data = filter_data_get(connection, service_filter, NULL, NULL,
 550                                 DBUS_INTERFACE_DBUS, "NameOwnerChanged",
 551                                 name);
 552         if (!data)
 553                 return 0;
 554
 555         cb = filter_data_add_callback(data, connect, disconnect, NULL, NULL,
 556                                         user_data);
 557         if (!cb)
 558                 return 0;
 559
 560         if (connect)
 561                 check_service(connection, name, connect, user_data);
 562
 563         return cb->id;
 564 }
 565
 566 guint g_dbus_add_disconnect_watch(DBusConnection *connection, const char *name,
 567                                 GDBusWatchFunction func,
 568                                 void *user_data, GDBusDestroyFunction destroy)
 569 {
 570         return g_dbus_add_service_watch(connection, name, NULL, func,
 571                                                         user_data, destroy);
 572 }
 573
 574 guint g_dbus_add_signal_watch(DBusConnection *connection,
 575                                 const char *sender, const char *path,
 576                                 const char *interface, const char *member,
 577                                 GDBusSignalFunction function, void *user_data,
 578                                 GDBusDestroyFunction destroy)
 579 {
 580         struct filter_data *data;
 581         struct filter_callback *cb;
 582
 583         data = filter_data_get(connection, signal_filter, sender, path,
 584                                 interface, member, NULL);
 585         if (!data)
 586                 return 0;
 587
 588         cb = filter_data_add_callback(data, NULL, NULL, function, destroy,
 589                                         user_data);
 590         if (!cb)
 591                 return 0;
 592
 593         return cb->id;
 594 }
 595
 596 gboolean g_dbus_remove_watch(DBusConnection *connection, guint id)
 597 {
 598         struct filter_data *data;
 599         struct filter_callback *cb;
 600         GSList *ldata;
 601
 602         if (id == 0)
 603                 return FALSE;
 604
 605         for (ldata = listeners; ldata; ldata = ldata->next) {
 606                 data = ldata->data;
 607
 608                 cb = filter_data_find_callback(data, id);
 609                 if (cb) {
 610                         filter_data_remove_callback(data, cb);
 611                         return TRUE;
 612                 }
 613         }
 614
 615         return FALSE;
 616 }
 617
 618 void g_dbus_remove_all_watches(DBusConnection *connection)
 619 {
 620         struct filter_data *data;
 621
 622         while ((data = filter_data_find(connection, NULL, NULL, NULL, NULL, NULL))) {
 623                 listeners = g_slist_remove(listeners, data);
 624                 filter_data_call_and_free(data);
 625         }
 626
 627         dbus_connection_remove_filter(connection, message_filter, NULL);
 628 }