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 service_data {
  47         DBusConnection *conn;
  48         DBusPendingCall *call;
  49         char *name;
  50         const char *owner;
  51         guint id;
  52         struct filter_callback *callback;
  53 };
  54
  55 struct filter_callback {
  56         GDBusWatchFunction conn_func;
  57         GDBusWatchFunction disc_func;
  58         GDBusSignalFunction signal_func;
  59         GDBusDestroyFunction destroy_func;
  60         struct service_data *data;
  61         void *user_data;
  62         guint id;
  63 };
  64
  65 struct filter_data {
  66         DBusConnection *connection;
  67         DBusHandleMessageFunction handle_func;
  68         char *name;
  69         char *owner;
  70         char *path;
  71         char *interface;
  72         char *member;
  73         char *argument;
  74         GSList *callbacks;
  75         GSList *processed;
  76         guint name_watch;
  77         gboolean lock;
  78         gboolean registered;
  79 };
  80
  81 static struct filter_data *filter_data_find(DBusConnection *connection,
  82                                                         const char *name,
  83                                                         const char *owner,
  84                                                         const char *path,
  85                                                         const char *interface,
  86                                                         const char *member,
  87                                                         const char *argument)
  88 {
  89         GSList *current;
  90
  91         for (current = listeners;
  92                         current != NULL; current = current->next) {
  93                 struct filter_data *data = current->data;
  94
  95                 if (connection != data->connection)
  96                         continue;
  97
  98                 if (name && data->name &&
  99                                 g_str_equal(name, data->name) == FALSE)
 100                         continue;
 101
 102                 if (owner && data->owner &&
 103                                 g_str_equal(owner, data->owner) == FALSE)
 104                         continue;
 105
 106                 if (path && data->path &&
 107                                 g_str_equal(path, data->path) == FALSE)
 108                         continue;
 109
 110                 if (interface && data->interface &&
 111                                 g_str_equal(interface, data->interface) == FALSE)
 112                         continue;
 113
 114                 if (member && data->member &&
 115                                 g_str_equal(member, data->member) == FALSE)
 116                         continue;
 117
 118                 if (argument && data->argument &&
 119                                 g_str_equal(argument, data->argument) == FALSE)
 120                         continue;
 121
 122                 return data;
 123         }
 124
 125         return NULL;
 126 }
 127
 128 static void format_rule(struct filter_data *data, char *rule, size_t size)
 129 {
 130         const char *sender;
 131         int offset;
 132
 133         offset = snprintf(rule, size, "type='signal'");
 134         sender = data->name ? : data->owner;
 135
 136         if (sender)
 137                 offset += snprintf(rule + offset, size - offset,
 138                                 ",sender='%s'", sender);
 139         if (data->path)
 140                 offset += snprintf(rule + offset, size - offset,
 141                                 ",path='%s'", data->path);
 142         if (data->interface)
 143                 offset += snprintf(rule + offset, size - offset,
 144                                 ",interface='%s'", data->interface);
 145         if (data->member)
 146                 offset += snprintf(rule + offset, size - offset,
 147                                 ",member='%s'", data->member);
 148         if (data->argument)
 149                 snprintf(rule + offset, size - offset,
 150                                 ",arg0='%s'", data->argument);
 151 }
 152
 153 static gboolean add_match(struct filter_data *data,
 154                                 DBusHandleMessageFunction filter)
 155 {
 156         DBusError err;
 157         char rule[DBUS_MAXIMUM_MATCH_RULE_LENGTH];
 158
 159         format_rule(data, rule, sizeof(rule));
 160         dbus_error_init(&err);
 161
 162         dbus_bus_add_match(data->connection, rule, &err);
 163         if (dbus_error_is_set(&err)) {
 164                 error("Adding match rule \"%s\" failed: %s", rule,
 165                                 err.message);
 166                 dbus_error_free(&err);
 167                 return FALSE;
 168         }
 169
 170         data->handle_func = filter;
 171         data->registered = TRUE;
 172
 173         return TRUE;
 174 }
 175
 176 static gboolean remove_match(struct filter_data *data)
 177 {
 178         DBusError err;
 179         char rule[DBUS_MAXIMUM_MATCH_RULE_LENGTH];
 180
 181         format_rule(data, rule, sizeof(rule));
 182
 183         dbus_error_init(&err);
 184
 185         dbus_bus_remove_match(data->connection, rule, &err);
 186         if (dbus_error_is_set(&err)) {
 187                 error("Removing owner match rule for %s failed: %s",
 188                                 rule, err.message);
 189                 dbus_error_free(&err);
 190                 return FALSE;
 191         }
 192
 193         return TRUE;
 194 }
 195
 196 static struct filter_data *filter_data_get(DBusConnection *connection,
 197                                         DBusHandleMessageFunction filter,
 198                                         const char *sender,
 199                                         const char *path,
 200                                         const char *interface,
 201                                         const char *member,
 202                                         const char *argument)
 203 {
 204         struct filter_data *data;
 205         const char *name = NULL, *owner = NULL;
 206
 207         if (!filter_data_find(connection, NULL, NULL, NULL, NULL, NULL,
 208                                 NULL)) {
 209                 if (!dbus_connection_add_filter(connection,
 210                                         message_filter, NULL, NULL)) {
 211                         error("dbus_connection_add_filter() failed");
 212                         return NULL;
 213                 }
 214         }
 215
 216         if (sender == NULL)
 217                 goto proceed;
 218
 219         if (sender[0] == ':')
 220                 owner = sender;
 221         else
 222                 name = sender;
 223
 224 proceed:
 225         data = filter_data_find(connection, name, owner, path, interface,
 226                                         member, argument);
 227         if (data)
 228                 return data;
 229
 230         data = g_new0(struct filter_data, 1);
 231
 232         data->connection = dbus_connection_ref(connection);
 233         data->name = name ? g_strdup(name) : NULL;
 234         data->owner = owner ? g_strdup(owner) : NULL;
 235         data->path = g_strdup(path);
 236         data->interface = g_strdup(interface);
 237         data->member = g_strdup(member);
 238         data->argument = g_strdup(argument);
 239
 240         if (!add_match(data, filter)) {
 241                 g_free(data);
 242                 return NULL;
 243         }
 244
 245         listeners = g_slist_append(listeners, data);
 246
 247         return data;
 248 }
 249
 250 static struct filter_callback *filter_data_find_callback(
 251                                                 struct filter_data *data,
 252                                                 guint id)
 253 {
 254         GSList *l;
 255
 256         for (l = data->callbacks; l; l = l->next) {
 257                 struct filter_callback *cb = l->data;
 258                 if (cb->id == id)
 259                         return cb;
 260         }
 261         for (l = data->processed; l; l = l->next) {
 262                 struct filter_callback *cb = l->data;
 263                 if (cb->id == id)
 264                         return cb;
 265         }
 266
 267         return NULL;
 268 }
 269
 270 static void filter_data_free(struct filter_data *data)
 271 {
 272         GSList *l;
 273
 274         for (l = data->callbacks; l != NULL; l = l->next)
 275                 g_free(l->data);
 276
 277         g_slist_free(data->callbacks);
 278         g_dbus_remove_watch(data->connection, data->name_watch);
 279         g_free(data->name);
 280         g_free(data->owner);
 281         g_free(data->path);
 282         g_free(data->interface);
 283         g_free(data->member);
 284         g_free(data->argument);
 285         dbus_connection_unref(data->connection);
 286         g_free(data);
 287 }
 288
 289 static void filter_data_call_and_free(struct filter_data *data)
 290 {
 291         GSList *l;
 292
 293         for (l = data->callbacks; l != NULL; l = l->next) {
 294                 struct filter_callback *cb = l->data;
 295                 if (cb->disc_func)
 296                         cb->disc_func(data->connection, cb->user_data);
 297                 if (cb->destroy_func)
 298                         cb->destroy_func(cb->user_data);
 299                 g_free(cb);
 300         }
 301
 302         filter_data_free(data);
 303 }
 304
 305 static struct filter_callback *filter_data_add_callback(
 306                                                 struct filter_data *data,
 307                                                 GDBusWatchFunction connect,
 308                                                 GDBusWatchFunction disconnect,
 309                                                 GDBusSignalFunction signal,
 310                                                 GDBusDestroyFunction destroy,
 311                                                 void *user_data)
 312 {
 313         struct filter_callback *cb = NULL;
 314
 315         cb = g_new0(struct filter_callback, 1);
 316
 317         cb->conn_func = connect;
 318         cb->disc_func = disconnect;
 319         cb->signal_func = signal;
 320         cb->destroy_func = destroy;
 321         cb->user_data = user_data;
 322         cb->id = ++listener_id;
 323
 324         if (data->lock)
 325                 data->processed = g_slist_append(data->processed, cb);
 326         else
 327                 data->callbacks = g_slist_append(data->callbacks, cb);
 328
 329         return cb;
 330 }
 331
 332 static void service_data_free(struct service_data *data)
 333 {
 334         struct filter_callback *callback = data->callback;
 335
 336         dbus_connection_unref(data->conn);
 337
 338         if (data->call)
 339                 dbus_pending_call_unref(data->call);
 340
 341         if (data->id)
 342                 g_source_remove(data->id);
 343
 344         g_free(data->name);
 345         g_free(data);
 346
 347         callback->data = NULL;
 348 }
 349
 350 static gboolean filter_data_remove_callback(struct filter_data *data,
 351                                                 struct filter_callback *cb)
 352 {
 353         DBusConnection *connection;
 354
 355         data->callbacks = g_slist_remove(data->callbacks, cb);
 356         data->processed = g_slist_remove(data->processed, cb);
 357
 358         /* Cancel pending operations */
 359         if (cb->data) {
 360                 if (cb->data->call)
 361                         dbus_pending_call_cancel(cb->data->call);
 362                 service_data_free(cb->data);
 363         }
 364
 365         if (cb->destroy_func)
 366                 cb->destroy_func(cb->user_data);
 367
 368         g_free(cb);
 369
 370         /* Don't remove the filter if other callbacks exist or data is lock
 371          * processing callbacks */
 372         if (data->callbacks || data->lock)
 373                 return TRUE;
 374
 375         if (data->registered && !remove_match(data))
 376                 return FALSE;
 377
 378         connection = dbus_connection_ref(data->connection);
 379         listeners = g_slist_remove(listeners, data);
 380         filter_data_free(data);
 381
 382         /* Remove filter if there are no listeners left for the connection */
 383         data = filter_data_find(connection, NULL, NULL, NULL, NULL, NULL,
 384                                         NULL);
 385         if (!data)
 386                 dbus_connection_remove_filter(connection, message_filter,
 387                                                 NULL);
 388
 389         dbus_connection_unref(connection);
 390
 391         return TRUE;
 392 }
 393
 394 static DBusHandlerResult signal_filter(DBusConnection *connection,
 395                                         DBusMessage *message, void *user_data)
 396 {
 397         struct filter_data *data = user_data;
 398         struct filter_callback *cb;
 399
 400         while (data->callbacks) {
 401                 cb = data->callbacks->data;
 402
 403                 if (cb->signal_func && !cb->signal_func(connection, message,
 404                                                         cb->user_data)) {
 405                         filter_data_remove_callback(data, cb);
 406                         continue;
 407                 }
 408
 409                 /* Check if the watch was removed/freed by the callback
 410                  * function */
 411                 if (!g_slist_find(data->callbacks, cb))
 412                         continue;
 413
 414                 data->callbacks = g_slist_remove(data->callbacks, cb);
 415                 data->processed = g_slist_append(data->processed, cb);
 416         }
 417
 418         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 419 }
 420
 421 static void update_name_cache(const char *name, const char *owner)
 422 {
 423         GSList *l;
 424
 425         for (l = listeners; l != NULL; l = l->next) {
 426                 struct filter_data *data = l->data;
 427
 428                 if (g_strcmp0(data->name, name) != 0)
 429                         continue;
 430
 431                 g_free(data->owner);
 432                 data->owner = g_strdup(owner);
 433         }
 434 }
 435
 436 static const char *check_name_cache(const char *name)
 437 {
 438         GSList *l;
 439
 440         for (l = listeners; l != NULL; l = l->next) {
 441                 struct filter_data *data = l->data;
 442
 443                 if (g_strcmp0(data->name, name) != 0)
 444                         continue;
 445
 446                 return data->owner;
 447         }
 448
 449         return NULL;
 450 }
 451
 452 static DBusHandlerResult service_filter(DBusConnection *connection,
 453                                         DBusMessage *message, void *user_data)
 454 {
 455         struct filter_data *data = user_data;
 456         struct filter_callback *cb;
 457         char *name, *old, *new;
 458
 459         if (!dbus_message_get_args(message, NULL,
 460                                 DBUS_TYPE_STRING, &name,
 461                                 DBUS_TYPE_STRING, &old,
 462                                 DBUS_TYPE_STRING, &new,
 463                                 DBUS_TYPE_INVALID)) {
 464                 error("Invalid arguments for NameOwnerChanged signal");
 465                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 466         }
 467
 468         update_name_cache(name, new);
 469
 470         while (data->callbacks) {
 471                 cb = data->callbacks->data;
 472
 473                 if (*new == '\0') {
 474                         if (cb->disc_func)
 475                                 cb->disc_func(connection, cb->user_data);
 476                 } else {
 477                         if (cb->conn_func)
 478                                 cb->conn_func(connection, cb->user_data);
 479                 }
 480
 481                 /* Only auto remove if it is a bus name watch */
 482                 if (data->argument[0] == ':' &&
 483                                 (!cb->conn_func || !cb->disc_func)) {
 484                         filter_data_remove_callback(data, cb);
 485                         continue;
 486                 }
 487
 488                 /* Check if the watch was removed/freed by the callback
 489                  * function */
 490                 if (!g_slist_find(data->callbacks, cb))
 491                         continue;
 492
 493                 data->callbacks = g_slist_remove(data->callbacks, cb);
 494                 data->processed = g_slist_append(data->processed, cb);
 495         }
 496
 497         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 498 }
 499
 500
 501 static DBusHandlerResult message_filter(DBusConnection *connection,
 502                                         DBusMessage *message, void *user_data)
 503 {
 504         struct filter_data *data;
 505         const char *sender, *path, *iface, *member, *arg = NULL;
 506
 507         /* Only filter signals */
 508         if (dbus_message_get_type(message) != DBUS_MESSAGE_TYPE_SIGNAL)
 509                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 510
 511         sender = dbus_message_get_sender(message);
 512         path = dbus_message_get_path(message);
 513         iface = dbus_message_get_interface(message);
 514         member = dbus_message_get_member(message);
 515         dbus_message_get_args(message, NULL, DBUS_TYPE_STRING, &arg, DBUS_TYPE_INVALID);
 516
 517         /* Sender is always bus name */
 518         data = filter_data_find(connection, NULL, sender, path, iface, member,
 519                                         arg);
 520         if (!data) {
 521                 error("Got %s.%s signal which has no listeners", iface, member);
 522                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 523         }
 524
 525         if (data->handle_func) {
 526                 data->lock = TRUE;
 527
 528                 data->handle_func(connection, message, data);
 529
 530                 data->callbacks = data->processed;
 531                 data->processed = NULL;
 532                 data->lock = FALSE;
 533         }
 534
 535         if (data->callbacks)
 536                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 537
 538         remove_match(data);
 539
 540         listeners = g_slist_remove(listeners, data);
 541         filter_data_free(data);
 542
 543         /* Remove filter if there no listener left for the connection */
 544         data = filter_data_find(connection, NULL, NULL, NULL, NULL, NULL,
 545                                         NULL);
 546         if (!data)
 547                 dbus_connection_remove_filter(connection, message_filter,
 548                                                 NULL);
 549
 550         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 551 }
 552
 553 static gboolean update_service(void *user_data)
 554 {
 555         struct service_data *data = user_data;
 556         struct filter_callback *cb = data->callback;
 557
 558         update_name_cache(data->name, data->owner);
 559         if (cb->conn_func)
 560                 cb->conn_func(data->conn, cb->user_data);
 561
 562         service_data_free(data);
 563
 564         return FALSE;
 565 }
 566
 567 static void service_reply(DBusPendingCall *call, void *user_data)
 568 {
 569         struct service_data *data = user_data;
 570         DBusMessage *reply;
 571         DBusError err;
 572
 573         reply = dbus_pending_call_steal_reply(call);
 574         if (reply == NULL)
 575                 return;
 576
 577         dbus_error_init(&err);
 578
 579         if (dbus_set_error_from_message(&err, reply))
 580                 goto fail;
 581
 582         if (dbus_message_get_args(reply, &err,
 583                                         DBUS_TYPE_STRING, &data->owner,
 584                                                 DBUS_TYPE_INVALID) == FALSE)
 585                 goto fail;
 586
 587         update_service(data);
 588
 589         goto done;
 590
 591 fail:
 592         error("%s", err.message);
 593         dbus_error_free(&err);
 594         service_data_free(data);
 595 done:
 596         dbus_message_unref(reply);
 597 }
 598
 599 static void check_service(DBusConnection *connection,
 600                                         const char *name,
 601                                         struct filter_callback *callback)
 602 {
 603         DBusMessage *message;
 604         struct service_data *data;
 605
 606         data = g_try_malloc0(sizeof(*data));
 607         if (data == NULL) {
 608                 error("Can't allocate data structure");
 609                 return;
 610         }
 611
 612         data->conn = dbus_connection_ref(connection);
 613         data->name = g_strdup(name);
 614         data->callback = callback;
 615         callback->data = data;
 616
 617         data->owner = check_name_cache(name);
 618         if (data->owner != NULL) {
 619                 data->id = g_idle_add(update_service, data);
 620                 return;
 621         }
 622
 623         message = dbus_message_new_method_call(DBUS_SERVICE_DBUS,
 624                         DBUS_PATH_DBUS, DBUS_INTERFACE_DBUS, "GetNameOwner");
 625         if (message == NULL) {
 626                 error("Can't allocate new message");
 627                 g_free(data);
 628                 return;
 629         }
 630
 631         dbus_message_append_args(message, DBUS_TYPE_STRING, &name,
 632                                                         DBUS_TYPE_INVALID);
 633
 634         if (dbus_connection_send_with_reply(connection, message,
 635                                                         &data->call, -1) == FALSE) {
 636                 error("Failed to execute method call");
 637                 g_free(data);
 638                 goto done;
 639         }
 640
 641         if (data->call == NULL) {
 642                 error("D-Bus connection not available");
 643                 g_free(data);
 644                 goto done;
 645         }
 646
 647         dbus_pending_call_set_notify(data->call, service_reply, data, NULL);
 648
 649 done:
 650         dbus_message_unref(message);
 651 }
 652
 653 guint g_dbus_add_service_watch(DBusConnection *connection, const char *name,
 654                                 GDBusWatchFunction connect,
 655                                 GDBusWatchFunction disconnect,
 656                                 void *user_data, GDBusDestroyFunction destroy)
 657 {
 658         struct filter_data *data;
 659         struct filter_callback *cb;
 660
 661         if (!name)
 662                 return 0;
 663
 664         data = filter_data_get(connection, service_filter, NULL, NULL,
 665                                 DBUS_INTERFACE_DBUS, "NameOwnerChanged",
 666                                 name);
 667         if (!data)
 668                 return 0;
 669
 670         cb = filter_data_add_callback(data, connect, disconnect, NULL, NULL,
 671                                         user_data);
 672         if (!cb)
 673                 return 0;
 674
 675         if (connect)
 676                 check_service(connection, name, cb);
 677
 678         return cb->id;
 679 }
 680
 681 guint g_dbus_add_disconnect_watch(DBusConnection *connection, const char *name,
 682                                 GDBusWatchFunction func,
 683                                 void *user_data, GDBusDestroyFunction destroy)
 684 {
 685         return g_dbus_add_service_watch(connection, name, NULL, func,
 686                                                         user_data, destroy);
 687 }
 688
 689 guint g_dbus_add_signal_watch(DBusConnection *connection,
 690                                 const char *sender, const char *path,
 691                                 const char *interface, const char *member,
 692                                 GDBusSignalFunction function, void *user_data,
 693                                 GDBusDestroyFunction destroy)
 694 {
 695         struct filter_data *data;
 696         struct filter_callback *cb;
 697
 698         data = filter_data_get(connection, signal_filter, sender, path,
 699                                 interface, member, NULL);
 700         if (!data)
 701                 return 0;
 702
 703         cb = filter_data_add_callback(data, NULL, NULL, function, destroy,
 704                                         user_data);
 705         if (!cb)
 706                 return 0;
 707
 708         if (data->name != NULL && data->name_watch == 0)
 709                 data->name_watch = g_dbus_add_service_watch(connection,
 710                                                         data->name, NULL,
 711                                                         NULL, NULL, NULL);
 712
 713         return cb->id;
 714 }
 715
 716 gboolean g_dbus_remove_watch(DBusConnection *connection, guint id)
 717 {
 718         struct filter_data *data;
 719         struct filter_callback *cb;
 720         GSList *ldata;
 721
 722         if (id == 0)
 723                 return FALSE;
 724
 725         for (ldata = listeners; ldata; ldata = ldata->next) {
 726                 data = ldata->data;
 727
 728                 cb = filter_data_find_callback(data, id);
 729                 if (cb) {
 730                         filter_data_remove_callback(data, cb);
 731                         return TRUE;
 732                 }
 733         }
 734
 735         return FALSE;
 736 }
 737
 738 void g_dbus_remove_all_watches(DBusConnection *connection)
 739 {
 740         struct filter_data *data;
 741
 742         while ((data = filter_data_find(connection, NULL, NULL, NULL, NULL,
 743                                         NULL, NULL))) {
 744                 listeners = g_slist_remove(listeners, data);
 745                 filter_data_call_and_free(data);
 746         }
 747
 748         dbus_connection_remove_filter(connection, message_filter, NULL);
 749 }