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