gdbus/watch.c

   1 /*
   2  *
   3  *  D-Bus helper library
   4  *
   5  *  Copyright (C) 2004-2010  Marcel Holtmann <marcel@holtmann.org>
   6  *
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to the Free Software
  20  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  21  *
  22  */
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #include <stdio.h>
  29 #include <string.h>
  30
  31 #include <glib.h>
  32 #include <dbus/dbus.h>
  33
  34 #include "gdbus.h"
  35
  36 #define info(fmt...)
  37 #define error(fmt...)
  38 #define debug(fmt...)
  39
  40 static DBusHandlerResult message_filter(DBusConnection *connection,
  41                                         DBusMessage *message, void *user_data);
  42
  43 static guint listener_id = 0;
  44 static GSList *listeners = NULL;
  45
  46 struct filter_callback {
  47         GDBusWatchFunction conn_func;
  48         GDBusWatchFunction disc_func;
  49         GDBusSignalFunction signal_func;
  50         GDBusDestroyFunction destroy_func;
  51         void *user_data;
  52         guint id;
  53 };
  54
  55 struct filter_data {
  56         DBusConnection *connection;
  57         DBusHandleMessageFunction handle_func;
  58         char *name;
  59         char *owner;
  60         char *path;
  61         char *interface;
  62         char *member;
  63         char *argument;
  64         GSList *callbacks;
  65         GSList *processed;
  66         guint name_watch;
  67         gboolean lock;
  68         gboolean registered;
  69 };
  70
  71 static struct filter_data *filter_data_find(DBusConnection *connection,
  72                                                         const char *name,
  73                                                         const char *owner,
  74                                                         const char *path,
  75                                                         const char *interface,
  76                                                         const char *member,
  77                                                         const char *argument)
  78 {
  79         GSList *current;
  80
  81         for (current = listeners;
  82                         current != NULL; current = current->next) {
  83                 struct filter_data *data = current->data;
  84
  85                 if (connection != data->connection)
  86                         continue;
  87
  88                 if (name && data->name &&
  89                                 g_str_equal(name, data->name) == FALSE)
  90                         continue;
  91
  92                 if (owner && data->owner &&
  93                                 g_str_equal(owner, data->owner) == FALSE)
  94                         continue;
  95
  96                 if (path && data->path &&
  97                                 g_str_equal(path, data->path) == FALSE)
  98                         continue;
  99
 100                 if (interface && data->interface &&
 101                                 g_str_equal(interface, data->interface) == FALSE)
 102                         continue;
 103
 104                 if (member && data->member &&
 105                                 g_str_equal(member, data->member) == FALSE)
 106                         continue;
 107
 108                 if (argument && data->argument &&
 109                                 g_str_equal(argument, data->argument) == FALSE)
 110                         continue;
 111
 112                 return data;
 113         }
 114
 115         return NULL;
 116 }
 117
 118 static void format_rule(struct filter_data *data, char *rule, size_t size)
 119 {
 120         const char *sender;
 121         int offset;
 122
 123         offset = snprintf(rule, size, "type='signal'");
 124         sender = data->name ? : data->owner;
 125
 126         if (sender)
 127                 offset += snprintf(rule + offset, size - offset,
 128                                 ",sender='%s'", sender);
 129         if (data->path)
 130                 offset += snprintf(rule + offset, size - offset,
 131                                 ",path='%s'", data->path);
 132         if (data->interface)
 133                 offset += snprintf(rule + offset, size - offset,
 134                                 ",interface='%s'", data->interface);
 135         if (data->member)
 136                 offset += snprintf(rule + offset, size - offset,
 137                                 ",member='%s'", data->member);
 138         if (data->argument)
 139                 snprintf(rule + offset, size - offset,
 140                                 ",arg0='%s'", data->argument);
 141 }
 142
 143 static gboolean add_match(struct filter_data *data,
 144                                 DBusHandleMessageFunction filter)
 145 {
 146         DBusError err;
 147         char rule[DBUS_MAXIMUM_MATCH_RULE_LENGTH];
 148
 149         format_rule(data, rule, sizeof(rule));
 150         dbus_error_init(&err);
 151
 152         dbus_bus_add_match(data->connection, rule, &err);
 153         if (dbus_error_is_set(&err)) {
 154                 error("Adding match rule \"%s\" failed: %s", rule,
 155                                 err.message);
 156                 dbus_error_free(&err);
 157                 return FALSE;
 158         }
 159
 160         data->handle_func = filter;
 161         data->registered = TRUE;
 162
 163         return TRUE;
 164 }
 165
 166 static gboolean remove_match(struct filter_data *data)
 167 {
 168         DBusError err;
 169         char rule[DBUS_MAXIMUM_MATCH_RULE_LENGTH];
 170
 171         format_rule(data, rule, sizeof(rule));
 172
 173         dbus_error_init(&err);
 174
 175         dbus_bus_remove_match(data->connection, rule, &err);
 176         if (dbus_error_is_set(&err)) {
 177                 error("Removing owner match rule for %s failed: %s",
 178                                 rule, err.message);
 179                 dbus_error_free(&err);
 180                 return FALSE;
 181         }
 182
 183         return TRUE;
 184 }
 185
 186 static struct filter_data *filter_data_get(DBusConnection *connection,
 187                                         DBusHandleMessageFunction filter,
 188                                         const char *sender,
 189                                         const char *path,
 190                                         const char *interface,
 191                                         const char *member,
 192                                         const char *argument)
 193 {
 194         struct filter_data *data;
 195         const char *name = NULL, *owner = NULL;
 196
 197         if (!filter_data_find(connection, NULL, NULL, NULL, NULL, NULL,
 198                                 NULL)) {
 199                 if (!dbus_connection_add_filter(connection,
 200                                         message_filter, NULL, NULL)) {
 201                         error("dbus_connection_add_filter() failed");
 202                         return NULL;
 203                 }
 204         }
 205
 206         if (sender == NULL)
 207                 goto proceed;
 208
 209         if (sender[0] == ':')
 210                 owner = sender;
 211         else
 212                 name = sender;
 213
 214 proceed:
 215         data = filter_data_find(connection, name, owner, path, interface,
 216                                         member, argument);
 217         if (data)
 218                 return data;
 219
 220         data = g_new0(struct filter_data, 1);
 221
 222         data->connection = dbus_connection_ref(connection);
 223         data->name = name ? g_strdup(name) : NULL;
 224         data->owner = owner ? g_strdup(owner) : NULL;
 225         data->path = g_strdup(path);
 226         data->interface = g_strdup(interface);
 227         data->member = g_strdup(member);
 228         data->argument = g_strdup(argument);
 229
 230         if (!add_match(data, filter)) {
 231                 g_free(data);
 232                 return NULL;
 233         }
 234
 235         listeners = g_slist_append(listeners, data);
 236
 237         return data;
 238 }
 239
 240 static struct filter_callback *filter_data_find_callback(
 241                                                 struct filter_data *data,
 242                                                 guint id)
 243 {
 244         GSList *l;
 245
 246         for (l = data->callbacks; l; l = l->next) {
 247                 struct filter_callback *cb = l->data;
 248                 if (cb->id == id)
 249                         return cb;
 250         }
 251         for (l = data->processed; l; l = l->next) {
 252                 struct filter_callback *cb = l->data;
 253                 if (cb->id == id)
 254                         return cb;
 255         }
 256
 257         return NULL;
 258 }
 259
 260 static void filter_data_free(struct filter_data *data)
 261 {
 262         GSList *l;
 263
 264         for (l = data->callbacks; l != NULL; l = l->next)
 265                 g_free(l->data);
 266
 267         g_slist_free(data->callbacks);
 268         g_dbus_remove_watch(data->connection, data->name_watch);
 269         g_free(data->name);
 270         g_free(data->owner);
 271         g_free(data->path);
 272         g_free(data->interface);
 273         g_free(data->member);
 274         g_free(data->argument);
 275         dbus_connection_unref(data->connection);
 276         g_free(data);
 277 }
 278
 279 static void filter_data_call_and_free(struct filter_data *data)
 280 {
 281         GSList *l;
 282
 283         for (l = data->callbacks; l != NULL; l = l->next) {
 284                 struct filter_callback *cb = l->data;
 285                 if (cb->disc_func)
 286                         cb->disc_func(data->connection, cb->user_data);
 287                 if (cb->destroy_func)
 288                         cb->destroy_func(cb->user_data);
 289                 g_free(cb);
 290         }
 291
 292         filter_data_free(data);
 293 }
 294
 295 static struct filter_callback *filter_data_add_callback(
 296                                                 struct filter_data *data,
 297                                                 GDBusWatchFunction connect,
 298                                                 GDBusWatchFunction disconnect,
 299                                                 GDBusSignalFunction signal,
 300                                                 GDBusDestroyFunction destroy,
 301                                                 void *user_data)
 302 {
 303         struct filter_callback *cb = NULL;
 304
 305         cb = g_new(struct filter_callback, 1);
 306
 307         cb->conn_func = connect;
 308         cb->disc_func = disconnect;
 309         cb->signal_func = signal;
 310         cb->destroy_func = destroy;
 311         cb->user_data = user_data;
 312         cb->id = ++listener_id;
 313
 314         if (data->lock)
 315                 data->processed = g_slist_append(data->processed, cb);
 316         else
 317                 data->callbacks = g_slist_append(data->callbacks, cb);
 318
 319         return cb;
 320 }
 321
 322 static gboolean filter_data_remove_callback(struct filter_data *data,
 323                                                 struct filter_callback *cb)
 324 {
 325         DBusConnection *connection;
 326
 327         data->callbacks = g_slist_remove(data->callbacks, cb);
 328         data->processed = g_slist_remove(data->processed, cb);
 329
 330         if (cb->destroy_func)
 331                 cb->destroy_func(cb->user_data);
 332
 333         g_free(cb);
 334
 335         /* Don't remove the filter if other callbacks exist or data is lock
 336          * processing callbacks */
 337         if (data->callbacks || data->lock)
 338                 return TRUE;
 339
 340         if (data->registered && !remove_match(data))
 341                 return FALSE;
 342
 343         connection = dbus_connection_ref(data->connection);
 344         listeners = g_slist_remove(listeners, data);
 345         filter_data_free(data);
 346
 347         /* Remove filter if there are no listeners left for the connection */
 348         data = filter_data_find(connection, NULL, NULL, NULL, NULL, NULL,
 349                                         NULL);
 350         if (!data)
 351                 dbus_connection_remove_filter(connection, message_filter,
 352                                                 NULL);
 353
 354         dbus_connection_unref(connection);
 355
 356         return TRUE;
 357 }
 358
 359 static DBusHandlerResult signal_filter(DBusConnection *connection,
 360                                         DBusMessage *message, void *user_data)
 361 {
 362         struct filter_data *data = user_data;
 363         struct filter_callback *cb;
 364
 365         while (data->callbacks) {
 366                 cb = data->callbacks->data;
 367
 368                 if (cb->signal_func && !cb->signal_func(connection, message,
 369                                                         cb->user_data)) {
 370                         filter_data_remove_callback(data, cb);
 371                         continue;
 372                 }
 373
 374                 /* Check if the watch was removed/freed by the callback
 375                  * function */
 376                 if (!g_slist_find(data->callbacks, cb))
 377                         continue;
 378
 379                 data->callbacks = g_slist_remove(data->callbacks, cb);
 380                 data->processed = g_slist_append(data->processed, cb);
 381         }
 382
 383         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 384 }
 385
 386 static void update_name_cache(const char *name, const char *owner)
 387 {
 388         GSList *l;
 389
 390         for (l = listeners; l != NULL; l = l->next) {
 391                 struct filter_data *data = l->data;
 392
 393                 if (g_strcmp0(data->name, name) != 0)
 394                         continue;
 395
 396                 g_free(data->owner);
 397                 data->owner = g_strdup(owner);
 398         }
 399 }
 400
 401 static const char *check_name_cache(const char *name)
 402 {
 403         GSList *l;
 404
 405         for (l = listeners; l != NULL; l = l->next) {
 406                 struct filter_data *data = l->data;
 407
 408                 if (g_strcmp0(data->name, name) != 0)
 409                         continue;
 410
 411                 return data->owner;
 412         }
 413
 414         return NULL;
 415 }
 416
 417 static DBusHandlerResult service_filter(DBusConnection *connection,
 418                                         DBusMessage *message, void *user_data)
 419 {
 420         struct filter_data *data = user_data;
 421         struct filter_callback *cb;
 422         char *name, *old, *new;
 423
 424         if (!dbus_message_get_args(message, NULL,
 425                                 DBUS_TYPE_STRING, &name,
 426                                 DBUS_TYPE_STRING, &old,
 427                                 DBUS_TYPE_STRING, &new,
 428                                 DBUS_TYPE_INVALID)) {
 429                 error("Invalid arguments for NameOwnerChanged signal");
 430                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 431         }
 432
 433         update_name_cache(name, new);
 434
 435         while (data->callbacks) {
 436                 cb = data->callbacks->data;
 437
 438                 if (*new == '\0') {
 439                         if (cb->disc_func)
 440                                 cb->disc_func(connection, cb->user_data);
 441                 } else {
 442                         if (cb->conn_func)
 443                                 cb->conn_func(connection, cb->user_data);
 444                 }
 445
 446                 /* Only auto remove if it is a bus name watch */
 447                 if (data->argument[0] == ':' &&
 448                                 (!cb->conn_func || !cb->disc_func)) {
 449                         filter_data_remove_callback(data, cb);
 450                         continue;
 451                 }
 452
 453                 /* Check if the watch was removed/freed by the callback
 454                  * function */
 455                 if (!g_slist_find(data->callbacks, cb))
 456                         continue;
 457
 458                 data->callbacks = g_slist_remove(data->callbacks, cb);
 459                 data->processed = g_slist_append(data->processed, cb);
 460         }
 461
 462         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 463 }
 464
 465
 466 static DBusHandlerResult message_filter(DBusConnection *connection,
 467                                         DBusMessage *message, void *user_data)
 468 {
 469         struct filter_data *data;
 470         const char *sender, *path, *iface, *member, *arg = NULL;
 471
 472         /* Only filter signals */
 473         if (dbus_message_get_type(message) != DBUS_MESSAGE_TYPE_SIGNAL)
 474                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 475
 476         sender = dbus_message_get_sender(message);
 477         path = dbus_message_get_path(message);
 478         iface = dbus_message_get_interface(message);
 479         member = dbus_message_get_member(message);
 480         dbus_message_get_args(message, NULL, DBUS_TYPE_STRING, &arg, DBUS_TYPE_INVALID);
 481
 482         /* Sender is always bus name */
 483         data = filter_data_find(connection, NULL, sender, path, iface, member,
 484                                         arg);
 485         if (!data) {
 486                 error("Got %s.%s signal which has no listeners", iface, member);
 487                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 488         }
 489
 490         if (data->handle_func) {
 491                 data->lock = TRUE;
 492
 493                 data->handle_func(connection, message, data);
 494
 495                 data->callbacks = data->processed;
 496                 data->processed = NULL;
 497                 data->lock = FALSE;
 498         }
 499
 500         if (data->callbacks)
 501                 return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 502
 503         remove_match(data);
 504
 505         listeners = g_slist_remove(listeners, data);
 506         filter_data_free(data);
 507
 508         /* Remove filter if there no listener left for the connection */
 509         data = filter_data_find(connection, NULL, NULL, NULL, NULL, NULL,
 510                                         NULL);
 511         if (!data)
 512                 dbus_connection_remove_filter(connection, message_filter,
 513                                                 NULL);
 514
 515         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 516 }
 517
 518 struct service_data {
 519         DBusConnection *conn;
 520         char *name;
 521         const char *owner;
 522         GDBusWatchFunction conn_func;
 523         void *user_data;
 524 };
 525
 526 static void service_data_free(struct service_data *data)
 527 {
 528         dbus_connection_unref(data->conn);
 529         g_free(data->name);
 530         g_free(data);
 531 }
 532
 533 static gboolean update_service(void *user_data)
 534 {
 535         struct service_data *data = user_data;
 536
 537         update_name_cache(data->name, data->owner);
 538         if (data->conn_func)
 539                 data->conn_func(data->conn, data->user_data);
 540
 541         service_data_free(data);
 542
 543         return FALSE;
 544 }
 545
 546 static void service_reply(DBusPendingCall *call, void *user_data)
 547 {
 548         struct service_data *data = user_data;
 549         DBusMessage *reply;
 550         DBusError err;
 551
 552         reply = dbus_pending_call_steal_reply(call);
 553         if (reply == NULL)
 554                 return;
 555
 556         dbus_error_init(&err);
 557
 558         if (dbus_set_error_from_message(&err, reply))
 559                 goto fail;
 560
 561         if (dbus_message_get_args(reply, &err,
 562                                         DBUS_TYPE_STRING, &data->owner,
 563                                                 DBUS_TYPE_INVALID) == FALSE)
 564                 goto fail;
 565
 566         update_service(data);
 567
 568         goto done;
 569
 570 fail:
 571         error("%s", err.message);
 572         dbus_error_free(&err);
 573         service_data_free(data);
 574 done:
 575         dbus_message_unref(reply);
 576 }
 577
 578 static void check_service(DBusConnection *connection, const char *name,
 579                                 GDBusWatchFunction connect, void *user_data)
 580 {
 581         DBusMessage *message;
 582         DBusPendingCall *call;
 583         struct service_data *data;
 584
 585         data = g_try_malloc0(sizeof(*data));
 586         if (data == NULL) {
 587                 error("Can't allocate data structure");
 588                 return;
 589         }
 590
 591         data->conn = dbus_connection_ref(connection);
 592         data->name = g_strdup(name);
 593         data->conn_func = connect;
 594         data->user_data = user_data;
 595
 596         data->owner = check_name_cache(name);
 597         if (data->owner != NULL) {
 598                 g_idle_add(update_service, data);
 599                 return;
 600         }
 601
 602         message = dbus_message_new_method_call(DBUS_SERVICE_DBUS,
 603                         DBUS_PATH_DBUS, DBUS_INTERFACE_DBUS, "GetNameOwner");
 604         if (message == NULL) {
 605                 error("Can't allocate new message");
 606                 g_free(data);
 607                 return;
 608         }
 609
 610         dbus_message_append_args(message, DBUS_TYPE_STRING, &name,
 611                                                         DBUS_TYPE_INVALID);
 612
 613         if (dbus_connection_send_with_reply(connection, message,
 614                                                         &call, -1) == FALSE) {
 615                 error("Failed to execute method call");
 616                 g_free(data);
 617                 goto done;
 618         }
 619
 620         if (call == NULL) {
 621                 error("D-Bus connection not available");
 622                 g_free(data);
 623                 goto done;
 624         }
 625
 626         dbus_pending_call_set_notify(call, service_reply, data, g_free);
 627
 628         dbus_pending_call_unref(call);
 629
 630 done:
 631         dbus_message_unref(message);
 632 }
 633
 634 guint g_dbus_add_service_watch(DBusConnection *connection, const char *name,
 635                                 GDBusWatchFunction connect,
 636                                 GDBusWatchFunction disconnect,
 637                                 void *user_data, GDBusDestroyFunction destroy)
 638 {
 639         struct filter_data *data;
 640         struct filter_callback *cb;
 641
 642         if (!name)
 643                 return 0;
 644
 645         data = filter_data_get(connection, service_filter, NULL, NULL,
 646                                 DBUS_INTERFACE_DBUS, "NameOwnerChanged",
 647                                 name);
 648         if (!data)
 649                 return 0;
 650
 651         cb = filter_data_add_callback(data, connect, disconnect, NULL, NULL,
 652                                         user_data);
 653         if (!cb)
 654                 return 0;
 655
 656         if (connect)
 657                 check_service(connection, name, connect, user_data);
 658
 659         return cb->id;
 660 }
 661
 662 guint g_dbus_add_disconnect_watch(DBusConnection *connection, const char *name,
 663                                 GDBusWatchFunction func,
 664                                 void *user_data, GDBusDestroyFunction destroy)
 665 {
 666         return g_dbus_add_service_watch(connection, name, NULL, func,
 667                                                         user_data, destroy);
 668 }
 669
 670 guint g_dbus_add_signal_watch(DBusConnection *connection,
 671                                 const char *sender, const char *path,
 672                                 const char *interface, const char *member,
 673                                 GDBusSignalFunction function, void *user_data,
 674                                 GDBusDestroyFunction destroy)
 675 {
 676         struct filter_data *data;
 677         struct filter_callback *cb;
 678
 679         data = filter_data_get(connection, signal_filter, sender, path,
 680                                 interface, member, NULL);
 681         if (!data)
 682                 return 0;
 683
 684         cb = filter_data_add_callback(data, NULL, NULL, function, destroy,
 685                                         user_data);
 686         if (!cb)
 687                 return 0;
 688
 689         if (data->name != NULL && data->name_watch == 0)
 690                 data->name_watch = g_dbus_add_service_watch(connection,
 691                                                         data->name, NULL,
 692                                                         NULL, NULL, NULL);
 693
 694         return cb->id;
 695 }
 696
 697 gboolean g_dbus_remove_watch(DBusConnection *connection, guint id)
 698 {
 699         struct filter_data *data;
 700         struct filter_callback *cb;
 701         GSList *ldata;
 702
 703         if (id == 0)
 704                 return FALSE;
 705
 706         for (ldata = listeners; ldata; ldata = ldata->next) {
 707                 data = ldata->data;
 708
 709                 cb = filter_data_find_callback(data, id);
 710                 if (cb) {
 711                         filter_data_remove_callback(data, cb);
 712                         return TRUE;
 713                 }
 714         }
 715
 716         return FALSE;
 717 }
 718
 719 void g_dbus_remove_all_watches(DBusConnection *connection)
 720 {
 721         struct filter_data *data;
 722
 723         while ((data = filter_data_find(connection, NULL, NULL, NULL, NULL,
 724                                         NULL, NULL))) {
 725                 listeners = g_slist_remove(listeners, data);
 726                 filter_data_call_and_free(data);
 727         }
 728
 729         dbus_connection_remove_filter(connection, message_filter, NULL);
 730 }