gdbus/watch.c

   1 /*
   2  *
   3  *  D-Bus helper library
   4  *
   5  *  Copyright (C) 2004-2011  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_match(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 (g_strcmp0(name, data->name) != 0)
  99                         continue;
 100
 101                 if (g_strcmp0(owner, data->owner) != 0)
 102                         continue;
 103
 104                 if (g_strcmp0(path, data->path) != 0)
 105                         continue;
 106
 107                 if (g_strcmp0(interface, data->interface) != 0)
 108                         continue;
 109
 110                 if (g_strcmp0(member, data->member) != 0)
 111                         continue;
 112
 113                 if (g_strcmp0(argument, data->argument) != 0)
 114                         continue;
 115
 116                 return data;
 117         }
 118
 119         return NULL;
 120 }
 121
 122 static struct filter_data *filter_data_find(DBusConnection *connection)
 123 {
 124         GSList *current;
 125
 126         for (current = listeners;
 127                         current != NULL; current = current->next) {
 128                 struct filter_data *data = current->data;
 129
 130                 if (connection != data->connection)
 131                         continue;
 132
 133                 return data;
 134         }
 135
 136         return NULL;
 137 }
 138
 139 static void format_rule(struct filter_data *data, char *rule, size_t size)
 140 {
 141         const char *sender;
 142         int offset;
 143
 144         offset = snprintf(rule, size, "type='signal'");
 145         sender = data->name ? : data->owner;
 146
 147         if (sender)
 148                 offset += snprintf(rule + offset, size - offset,
 149                                 ",sender='%s'", sender);
 150         if (data->path)
 151                 offset += snprintf(rule + offset, size - offset,
 152                                 ",path='%s'", data->path);
 153         if (data->interface)
 154                 offset += snprintf(rule + offset, size - offset,
 155                                 ",interface='%s'", data->interface);
 156         if (data->member)
 157                 offset += snprintf(rule + offset, size - offset,
 158                                 ",member='%s'", data->member);
 159         if (data->argument)
 160                 snprintf(rule + offset, size - offset,
 161                                 ",arg0='%s'", data->argument);
 162 }
 163
 164 static gboolean add_match(struct filter_data *data,
 165                                 DBusHandleMessageFunction filter)
 166 {
 167         DBusError err;
 168         char rule[DBUS_MAXIMUM_MATCH_RULE_LENGTH];
 169
 170         format_rule(data, rule, sizeof(rule));
 171         dbus_error_init(&err);
 172
 173         dbus_bus_add_match(data->connection, rule, &err);
 174         if (dbus_error_is_set(&err)) {
 175                 error("Adding match rule \"%s\" failed: %s", rule,
 176                                 err.message);
 177                 dbus_error_free(&err);
 178                 return FALSE;
 179         }
 180
 181         data->handle_func = filter;
 182         data->registered = TRUE;
 183
 184         return TRUE;
 185 }
 186
 187 static gboolean remove_match(struct filter_data *data)
 188 {
 189         DBusError err;
 190         char rule[DBUS_MAXIMUM_MATCH_RULE_LENGTH];
 191
 192         format_rule(data, rule, sizeof(rule));
 193
 194         dbus_error_init(&err);
 195
 196         dbus_bus_remove_match(data->connection, rule, &err);
 197         if (dbus_error_is_set(&err)) {
 198                 error("Removing owner match rule for %s failed: %s",
 199                                 rule, err.message);
 200                 dbus_error_free(&err);
 201                 return FALSE;
 202         }
 203
 204         return TRUE;
 205 }
 206
 207 static struct filter_data *filter_data_get(DBusConnection *connection,
 208                                         DBusHandleMessageFunction filter,
 209                                         const char *sender,
 210                                         const char *path,
 211                                         const char *interface,
 212                                         const char *member,
 213                                         const char *argument)
 214 {
 215         struct filter_data *data;
 216         const char *name = NULL, *owner = NULL;
 217
 218         if (filter_data_find(connection) == NULL) {
 219                 if (!dbus_connection_add_filter(connection,
 220                                         message_filter, NULL, NULL)) {
 221                         error("dbus_connection_add_filter() failed");
 222                         return NULL;
 223                 }
 224         }
 225
 226         if (sender == NULL)
 227                 goto proceed;
 228
 229         if (sender[0] == ':')
 230                 owner = sender;
 231         else
 232                 name = sender;
 233
 234 proceed:
 235         data = filter_data_find_match(connection, name, owner, path,
 236                                                 interface, member, argument);
 237         if (data)
 238                 return data;
 239
 240         data = g_new0(struct filter_data, 1);
 241
 242         data->connection = dbus_connection_ref(connection);
 243         data->name = g_strdup(name);
 244         data->owner = g_strdup(owner);
 245         data->path = g_strdup(path);
 246         data->interface = g_strdup(interface);
 247         data->member = g_strdup(member);
 248         data->argument = g_strdup(argument);
 249
 250         if (!add_match(data, filter)) {
 251                 g_free(data);
 252                 return NULL;
 253         }
 254
 255         listeners = g_slist_append(listeners, data);
 256
 257         return data;
 258 }
 259
 260 static struct filter_callback *filter_data_find_callback(
 261                                                 struct filter_data *data,
 262                                                 guint id)
 263 {
 264         GSList *l;
 265
 266         for (l = data->callbacks; l; l = l->next) {
 267                 struct filter_callback *cb = l->data;
 268                 if (cb->id == id)
 269                         return cb;
 270         }
 271         for (l = data->processed; l; l = l->next) {
 272                 struct filter_callback *cb = l->data;
 273                 if (cb->id == id)
 274                         return cb;
 275         }
 276
 277         return NULL;
 278 }
 279
 280 static void filter_data_free(struct filter_data *data)
 281 {
 282         GSList *l;
 283
 284         for (l = data->callbacks; l != NULL; l = l->next)
 285                 g_free(l->data);
 286
 287         g_slist_free(data->callbacks);
 288         g_dbus_remove_watch(data->connection, data->name_watch);
 289         g_free(data->name);
 290         g_free(data->owner);
 291         g_free(data->path);
 292         g_free(data->interface);
 293         g_free(data->member);
 294         g_free(data->argument);
 295         dbus_connection_unref(data->connection);
 296         g_free(data);
 297 }
 298
 299 static void filter_data_call_and_free(struct filter_data *data)
 300 {
 301         GSList *l;
 302
 303         for (l = data->callbacks; l != NULL; l = l->next) {
 304                 struct filter_callback *cb = l->data;
 305                 if (cb->disc_func)
 306                         cb->disc_func(data->connection, cb->user_data);
 307                 if (cb->destroy_func)
 308                         cb->destroy_func(cb->user_data);
 309                 g_free(cb);
 310         }
 311
 312         filter_data_free(data);
 313 }
 314
 315 static struct filter_callback *filter_data_add_callback(
 316                                                 struct filter_data *data,
 317                                                 GDBusWatchFunction connect,
 318                                                 GDBusWatchFunction disconnect,
 319                                                 GDBusSignalFunction signal,
 320                                                 GDBusDestroyFunction destroy,
 321                                                 void *user_data)
 322 {
 323         struct filter_callback *cb = NULL;
 324
 325         cb = g_new0(struct filter_callback, 1);
 326
 327         cb->conn_func = connect;
 328         cb->disc_func = disconnect;
 329         cb->signal_func = signal;
 330         cb->destroy_func = destroy;
 331         cb->user_data = user_data;
 332         cb->id = ++listener_id;
 333
 334         if (data->lock)
 335                 data->processed = g_slist_append(data->processed, cb);
 336         else
 337                 data->callbacks = g_slist_append(data->callbacks, cb);
 338
 339         return cb;
 340 }
 341
 342 static void service_data_free(struct service_data *data)
 343 {
 344         struct filter_callback *callback = data->callback;
 345
 346         dbus_connection_unref(data->conn);
 347
 348         if (data->call)
 349                 dbus_pending_call_unref(data->call);
 350
 351         if (data->id)
 352                 g_source_remove(data->id);
 353
 354         g_free(data->name);
 355         g_free(data);
 356
 357         callback->data = NULL;
 358 }
 359
 360 static gboolean filter_data_remove_callback(struct filter_data *data,
 361                                                 struct filter_callback *cb)
 362 {
 363         DBusConnection *connection;
 364
 365         data->callbacks = g_slist_remove(data->callbacks, cb);
 366         data->processed = g_slist_remove(data->processed, cb);
 367
 368         /* Cancel pending operations */
 369         if (cb->data) {
 370                 if (cb->data->call)
 371                         dbus_pending_call_cancel(cb->data->call);
 372                 service_data_free(cb->data);
 373         }
 374
 375         if (cb->destroy_func)
 376                 cb->destroy_func(cb->user_data);
 377
 378         g_free(cb);
 379
 380         /* Don't remove the filter if other callbacks exist or data is lock
 381          * processing callbacks */
 382         if (data->callbacks || data->lock)
 383                 return TRUE;
 384
 385         if (data->registered && !remove_match(data))
 386                 return FALSE;
 387
 388         connection = dbus_connection_ref(data->connection);
 389         listeners = g_slist_remove(listeners, data);
 390
 391         /* Remove filter if there are no listeners left for the connection */
 392         if (filter_data_find(connection) == NULL)
 393                 dbus_connection_remove_filter(connection, message_filter,
 394                                                 NULL);
 395
 396         filter_data_free(data);
 397         dbus_connection_unref(connection);
 398
 399         return TRUE;
 400 }
 401
 402 static DBusHandlerResult signal_filter(DBusConnection *connection,
 403                                         DBusMessage *message, void *user_data)
 404 {
 405         struct filter_data *data = user_data;
 406         struct filter_callback *cb;
 407
 408         while (data->callbacks) {
 409                 cb = data->callbacks->data;
 410
 411                 if (cb->signal_func && !cb->signal_func(connection, message,
 412                                                         cb->user_data)) {
 413                         filter_data_remove_callback(data, cb);
 414                         continue;
 415                 }
 416
 417                 /* Check if the watch was removed/freed by the callback
 418                  * function */
 419                 if (!g_slist_find(data->callbacks, cb))
 420                         continue;
 421
 422                 data->callbacks = g_slist_remove(data->callbacks, cb);
 423                 data->processed = g_slist_append(data->processed, cb);
 424         }
 425
 426         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 427 }
 428
 429 static void update_name_cache(const char *name, const char *owner)
 430 {
 431         GSList *l;
 432
 433         for (l = listeners; l != NULL; l = l->next) {
 434                 struct filter_data *data = l->data;
 435
 436                 if (g_strcmp0(data->name, name) != 0)
 437                         continue;
 438
 439                 g_free(data->owner);
 440                 data->owner = g_strdup(owner);
 441         }
 442 }
 443
 444 static const char *check_name_cache(const char *name)
 445 {
 446         GSList *l;
 447
 448         for (l = listeners; l != NULL; l = l->next) {
 449                 struct filter_data *data = l->data;
 450
 451                 if (g_strcmp0(data->name, name) != 0)
 452                         continue;
 453
 454                 return data->owner;
 455         }
 456
 457         return NULL;
 458 }
 459
 460 static DBusHandlerResult service_filter(DBusConnection *connection,
 461                                         DBusMessage *message, void *user_data)
 462 {
 463         struct filter_data *data = user_data;
 464         struct filter_callback *cb;
 465         char *name, *old, *new;
 466
 467         if (!dbus_message_get_args(message, NULL,
 468                                 DBUS_TYPE_STRING, &name,
 469                                 DBUS_TYPE_STRING, &old,
 470                                 DBUS_TYPE_STRING, &new,
 471                                 DBUS_TYPE_INVALID)) {
 472                 error("Invalid arguments for NameOwnerChanged signal");
 473                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 474         }
 475
 476         update_name_cache(name, new);
 477
 478         while (data->callbacks) {
 479                 cb = data->callbacks->data;
 480
 481                 if (*new == '\0') {
 482                         if (cb->disc_func)
 483                                 cb->disc_func(connection, cb->user_data);
 484                 } else {
 485                         if (cb->conn_func)
 486                                 cb->conn_func(connection, cb->user_data);
 487                 }
 488
 489                 /* Check if the watch was removed/freed by the callback
 490                  * function */
 491                 if (!g_slist_find(data->callbacks, cb))
 492                         continue;
 493
 494                 /* Only auto remove if it is a bus name watch */
 495                 if (data->argument[0] == ':' &&
 496                                 (cb->conn_func == NULL || cb->disc_func == NULL)) {
 497                         filter_data_remove_callback(data, cb);
 498                         continue;
 499                 }
 500
 501                 data->callbacks = g_slist_remove(data->callbacks, cb);
 502                 data->processed = g_slist_append(data->processed, cb);
 503         }
 504
 505         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 506 }
 507
 508
 509 static DBusHandlerResult message_filter(DBusConnection *connection,
 510                                         DBusMessage *message, void *user_data)
 511 {
 512         struct filter_data *data;
 513         const char *sender, *path, *iface, *member, *arg = NULL;
 514         GSList *current, *delete_listener = NULL;
 515
 516         /* Only filter signals */
 517         if (dbus_message_get_type(message) != DBUS_MESSAGE_TYPE_SIGNAL)
 518                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 519
 520         sender = dbus_message_get_sender(message);
 521         path = dbus_message_get_path(message);
 522         iface = dbus_message_get_interface(message);
 523         member = dbus_message_get_member(message);
 524         dbus_message_get_args(message, NULL, DBUS_TYPE_STRING, &arg, DBUS_TYPE_INVALID);
 525
 526         /* Sender is always the owner */
 527
 528         for (current = listeners; current != NULL; current = current->next) {
 529                 data = current->data;
 530
 531                 if (connection != data->connection)
 532                         continue;
 533
 534                 if (data->owner && g_str_equal(sender, data->owner) == FALSE)
 535                         continue;
 536
 537                 if (data->path && g_str_equal(path, data->path) == FALSE)
 538                         continue;
 539
 540                 if (data->interface && g_str_equal(iface,
 541                                                 data->interface) == FALSE)
 542                         continue;
 543
 544                 if (data->member && g_str_equal(member, data->member) == FALSE)
 545                         continue;
 546
 547                 if (data->argument && g_str_equal(arg,
 548                                                 data->argument) == FALSE)
 549                         continue;
 550
 551                 if (data->handle_func) {
 552                         data->lock = TRUE;
 553
 554                         data->handle_func(connection, message, data);
 555
 556                         data->callbacks = data->processed;
 557                         data->processed = NULL;
 558                         data->lock = FALSE;
 559                 }
 560
 561                 if (!data->callbacks)
 562                         delete_listener = g_slist_prepend(delete_listener,
 563                                                                 current);
 564         }
 565
 566         for (current = delete_listener; current != NULL;
 567                                         current = delete_listener->next) {
 568                 GSList *l = current->data;
 569
 570                 data = l->data;
 571
 572                 /* Has any other callback added callbacks back to this data? */
 573                 if (data->callbacks != NULL)
 574                         continue;
 575
 576                 remove_match(data);
 577                 listeners = g_slist_delete_link(listeners, l);
 578
 579                 filter_data_free(data);
 580         }
 581
 582         g_slist_free(delete_listener);
 583
 584         /* Remove filter if there are no listeners left for the connection */
 585         if (filter_data_find(connection) == NULL)
 586                 dbus_connection_remove_filter(connection, message_filter,
 587                                                 NULL);
 588
 589         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 590 }
 591
 592 static gboolean update_service(void *user_data)
 593 {
 594         struct service_data *data = user_data;
 595         struct filter_callback *cb = data->callback;
 596
 597         update_name_cache(data->name, data->owner);
 598         if (cb->conn_func)
 599                 cb->conn_func(data->conn, cb->user_data);
 600
 601         service_data_free(data);
 602
 603         return FALSE;
 604 }
 605
 606 static void service_reply(DBusPendingCall *call, void *user_data)
 607 {
 608         struct service_data *data = user_data;
 609         DBusMessage *reply;
 610         DBusError err;
 611
 612         reply = dbus_pending_call_steal_reply(call);
 613         if (reply == NULL)
 614                 return;
 615
 616         dbus_error_init(&err);
 617
 618         if (dbus_set_error_from_message(&err, reply))
 619                 goto fail;
 620
 621         if (dbus_message_get_args(reply, &err,
 622                                         DBUS_TYPE_STRING, &data->owner,
 623                                                 DBUS_TYPE_INVALID) == FALSE)
 624                 goto fail;
 625
 626         update_service(data);
 627
 628         goto done;
 629
 630 fail:
 631         error("%s", err.message);
 632         dbus_error_free(&err);
 633         service_data_free(data);
 634 done:
 635         dbus_message_unref(reply);
 636 }
 637
 638 static void check_service(DBusConnection *connection,
 639                                         const char *name,
 640                                         struct filter_callback *callback)
 641 {
 642         DBusMessage *message;
 643         struct service_data *data;
 644
 645         data = g_try_malloc0(sizeof(*data));
 646         if (data == NULL) {
 647                 error("Can't allocate data structure");
 648                 return;
 649         }
 650
 651         data->conn = dbus_connection_ref(connection);
 652         data->name = g_strdup(name);
 653         data->callback = callback;
 654         callback->data = data;
 655
 656         data->owner = check_name_cache(name);
 657         if (data->owner != NULL) {
 658                 data->id = g_idle_add(update_service, data);
 659                 return;
 660         }
 661
 662         message = dbus_message_new_method_call(DBUS_SERVICE_DBUS,
 663                         DBUS_PATH_DBUS, DBUS_INTERFACE_DBUS, "GetNameOwner");
 664         if (message == NULL) {
 665                 error("Can't allocate new message");
 666                 g_free(data);
 667                 return;
 668         }
 669
 670         dbus_message_append_args(message, DBUS_TYPE_STRING, &name,
 671                                                         DBUS_TYPE_INVALID);
 672
 673         if (dbus_connection_send_with_reply(connection, message,
 674                                                         &data->call, -1) == FALSE) {
 675                 error("Failed to execute method call");
 676                 g_free(data);
 677                 goto done;
 678         }
 679
 680         if (data->call == NULL) {
 681                 error("D-Bus connection not available");
 682                 g_free(data);
 683                 goto done;
 684         }
 685
 686         dbus_pending_call_set_notify(data->call, service_reply, data, NULL);
 687
 688 done:
 689         dbus_message_unref(message);
 690 }
 691
 692 guint g_dbus_add_service_watch(DBusConnection *connection, const char *name,
 693                                 GDBusWatchFunction connect,
 694                                 GDBusWatchFunction disconnect,
 695                                 void *user_data, GDBusDestroyFunction destroy)
 696 {
 697         struct filter_data *data;
 698         struct filter_callback *cb;
 699
 700         if (name == NULL)
 701                 return 0;
 702
 703         data = filter_data_get(connection, service_filter, NULL, NULL,
 704                                 DBUS_INTERFACE_DBUS, "NameOwnerChanged",
 705                                 name);
 706         if (data == NULL)
 707                 return 0;
 708
 709         cb = filter_data_add_callback(data, connect, disconnect, NULL, destroy,
 710                                         user_data);
 711         if (cb == NULL)
 712                 return 0;
 713
 714         if (connect)
 715                 check_service(connection, name, cb);
 716
 717         return cb->id;
 718 }
 719
 720 guint g_dbus_add_disconnect_watch(DBusConnection *connection, const char *name,
 721                                 GDBusWatchFunction func,
 722                                 void *user_data, GDBusDestroyFunction destroy)
 723 {
 724         return g_dbus_add_service_watch(connection, name, NULL, func,
 725                                                         user_data, destroy);
 726 }
 727
 728 guint g_dbus_add_signal_watch(DBusConnection *connection,
 729                                 const char *sender, const char *path,
 730                                 const char *interface, const char *member,
 731                                 GDBusSignalFunction function, void *user_data,
 732                                 GDBusDestroyFunction destroy)
 733 {
 734         struct filter_data *data;
 735         struct filter_callback *cb;
 736
 737         data = filter_data_get(connection, signal_filter, sender, path,
 738                                 interface, member, NULL);
 739         if (data == NULL)
 740                 return 0;
 741
 742         cb = filter_data_add_callback(data, NULL, NULL, function, destroy,
 743                                         user_data);
 744         if (cb == NULL)
 745                 return 0;
 746
 747         if (data->name != NULL && data->name_watch == 0)
 748                 data->name_watch = g_dbus_add_service_watch(connection,
 749                                                         data->name, NULL,
 750                                                         NULL, NULL, NULL);
 751
 752         return cb->id;
 753 }
 754
 755 gboolean g_dbus_remove_watch(DBusConnection *connection, guint id)
 756 {
 757         struct filter_data *data;
 758         struct filter_callback *cb;
 759         GSList *ldata;
 760
 761         if (id == 0)
 762                 return FALSE;
 763
 764         for (ldata = listeners; ldata; ldata = ldata->next) {
 765                 data = ldata->data;
 766
 767                 cb = filter_data_find_callback(data, id);
 768                 if (cb) {
 769                         filter_data_remove_callback(data, cb);
 770                         return TRUE;
 771                 }
 772         }
 773
 774         return FALSE;
 775 }
 776
 777 void g_dbus_remove_all_watches(DBusConnection *connection)
 778 {
 779         struct filter_data *data;
 780
 781         while ((data = filter_data_find(connection))) {
 782                 listeners = g_slist_remove(listeners, data);
 783                 filter_data_call_and_free(data);
 784         }
 785
 786         dbus_connection_remove_filter(connection, message_filter, NULL);
 787 }