dbus.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 #include <dbus/dbus.h>
   4
   5 #include <sys/epoll.h>
   6 #include <sys/timerfd.h>
   7 #include <errno.h>
   8 #include <unistd.h>
   9
  10 #include "dbus.h"
  11 #include "log.h"
  12 #include "strv.h"
  13
  14 static void bus_dispatch_status(DBusConnection *bus, DBusDispatchStatus status, void *data)  {
  15         Manager *m = data;
  16
  17         assert(bus);
  18         assert(m);
  19
  20         m->request_bus_dispatch = status != DBUS_DISPATCH_COMPLETE;
  21 }
  22
  23 static uint32_t bus_flags_to_events(DBusWatch *bus_watch) {
  24         unsigned flags;
  25         uint32_t events = 0;
  26
  27         assert(bus_watch);
  28
  29         /* no watch flags for disabled watches */
  30         if (!dbus_watch_get_enabled(bus_watch))
  31                 return 0;
  32
  33         flags = dbus_watch_get_flags(bus_watch);
  34
  35         if (flags & DBUS_WATCH_READABLE)
  36                 events |= EPOLLIN;
  37         if (flags & DBUS_WATCH_WRITABLE)
  38                 events |= EPOLLOUT;
  39
  40         return events | EPOLLHUP | EPOLLERR;
  41 }
  42
  43 static unsigned events_to_bus_flags(uint32_t events) {
  44         unsigned flags = 0;
  45
  46         if (events & EPOLLIN)
  47                 flags |= DBUS_WATCH_READABLE;
  48         if (events & EPOLLOUT)
  49                 flags |= DBUS_WATCH_WRITABLE;
  50         if (events & EPOLLHUP)
  51                 flags |= DBUS_WATCH_HANGUP;
  52         if (events & EPOLLERR)
  53                 flags |= DBUS_WATCH_ERROR;
  54
  55         return flags;
  56 }
  57
  58 void bus_watch_event(Manager *m, Watch *w, int events) {
  59         assert(m);
  60         assert(w);
  61
  62         /* This is called by the event loop whenever there is
  63          * something happening on D-Bus' file handles. */
  64
  65         if (!(dbus_watch_get_enabled(w->data.bus_watch)))
  66                 return;
  67
  68         dbus_watch_handle(w->data.bus_watch, events_to_bus_flags(events));
  69 }
  70
  71 static dbus_bool_t bus_add_watch(DBusWatch *bus_watch, void *data) {
  72         Manager *m = data;
  73         Watch *w;
  74         struct epoll_event ev;
  75
  76         assert(bus_watch);
  77         assert(m);
  78
  79         if (!(w = new0(Watch, 1)))
  80                 return FALSE;
  81
  82         w->fd = dbus_watch_get_unix_fd(bus_watch);
  83         w->type = WATCH_DBUS_WATCH;
  84         w->data.bus_watch = bus_watch;
  85
  86         zero(ev);
  87         ev.events = bus_flags_to_events(bus_watch);
  88         ev.data.ptr = w;
  89
  90         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, w->fd, &ev) < 0) {
  91
  92                 if (errno != EEXIST) {
  93                         free(w);
  94                         return FALSE;
  95                 }
  96
  97                 /* Hmm, bloody D-Bus creates multiple watches on the
  98                  * same fd. epoll() does not like that. As a dirty
  99                  * hack we simply dup() the fd and hence get a second
 100                  * one we can safely add to the epoll(). */
 101
 102                 if ((w->fd = dup(w->fd)) < 0) {
 103                         free(w);
 104                         return FALSE;
 105                 }
 106
 107                 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, w->fd, &ev) < 0) {
 108                         free(w);
 109                         close_nointr_nofail(w->fd);
 110                         return FALSE;
 111                 }
 112
 113                 w->fd_is_dupped = true;
 114         }
 115
 116         dbus_watch_set_data(bus_watch, w, NULL);
 117
 118         return TRUE;
 119 }
 120
 121 static void bus_remove_watch(DBusWatch *bus_watch, void *data) {
 122         Manager *m = data;
 123         Watch *w;
 124
 125         assert(bus_watch);
 126         assert(m);
 127
 128         if (!(w = dbus_watch_get_data(bus_watch)))
 129                 return;
 130
 131         assert(w->type == WATCH_DBUS_WATCH);
 132         assert_se(epoll_ctl(m->epoll_fd, EPOLL_CTL_DEL, w->fd, NULL) >= 0);
 133
 134         if (w->fd_is_dupped)
 135                 close_nointr_nofail(w->fd);
 136
 137         free(w);
 138 }
 139
 140 static void bus_toggle_watch(DBusWatch *bus_watch, void *data) {
 141         Manager *m = data;
 142         Watch *w;
 143         struct epoll_event ev;
 144
 145         assert(bus_watch);
 146         assert(m);
 147
 148         assert_se(w = dbus_watch_get_data(bus_watch));
 149         assert(w->type == WATCH_DBUS_WATCH);
 150
 151         zero(ev);
 152         ev.events = bus_flags_to_events(bus_watch);
 153         ev.data.ptr = w;
 154
 155         assert_se(epoll_ctl(m->epoll_fd, EPOLL_CTL_MOD, w->fd, &ev) == 0);
 156 }
 157
 158 static int bus_timeout_arm(Manager *m, Watch *w) {
 159         struct itimerspec its;
 160
 161         assert(m);
 162         assert(w);
 163
 164         zero(its);
 165
 166         if (dbus_timeout_get_enabled(w->data.bus_timeout)) {
 167                 timespec_store(&its.it_value, dbus_timeout_get_interval(w->data.bus_timeout) * USEC_PER_MSEC);
 168                 its.it_interval = its.it_interval;
 169         }
 170
 171         if (timerfd_settime(w->fd, 0, &its, NULL) < 0)
 172                 return -errno;
 173
 174         return 0;
 175 }
 176
 177 void bus_timeout_event(Manager *m, Watch *w, int events) {
 178         assert(m);
 179         assert(w);
 180
 181         /* This is called by the event loop whenever there is
 182          * something happening on D-Bus' file handles. */
 183
 184         if (!(dbus_timeout_get_enabled(w->data.bus_timeout)))
 185                 return;
 186
 187         dbus_timeout_handle(w->data.bus_timeout);
 188 }
 189
 190 static dbus_bool_t bus_add_timeout(DBusTimeout *timeout, void *data) {
 191         Manager *m = data;
 192         Watch *w;
 193         struct epoll_event ev;
 194
 195         assert(timeout);
 196         assert(m);
 197
 198         if (!(w = new0(Watch, 1)))
 199                 return FALSE;
 200
 201         if (!(w->fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK|TFD_CLOEXEC)) < 0)
 202                 goto fail;
 203
 204         w->type = WATCH_DBUS_TIMEOUT;
 205         w->data.bus_timeout = timeout;
 206
 207         if (bus_timeout_arm(m, w) < 0)
 208                 goto fail;
 209
 210         zero(ev);
 211         ev.events = EPOLLIN;
 212         ev.data.ptr = w;
 213
 214         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, w->fd, &ev) < 0)
 215                 goto fail;
 216
 217         dbus_timeout_set_data(timeout, w, NULL);
 218
 219         return TRUE;
 220
 221 fail:
 222         if (w->fd >= 0)
 223                 close_nointr_nofail(w->fd);
 224
 225         free(w);
 226         return FALSE;
 227 }
 228
 229 static void bus_remove_timeout(DBusTimeout *timeout, void *data) {
 230         Manager *m = data;
 231         Watch *w;
 232
 233         assert(timeout);
 234         assert(m);
 235
 236         if (!(w = dbus_timeout_get_data(timeout)))
 237                 return;
 238
 239         assert(w->type == WATCH_DBUS_TIMEOUT);
 240         assert_se(epoll_ctl(m->epoll_fd, EPOLL_CTL_DEL, w->fd, NULL) >= 0);
 241         close_nointr_nofail(w->fd);
 242         free(w);
 243 }
 244
 245 static void bus_toggle_timeout(DBusTimeout *timeout, void *data) {
 246         Manager *m = data;
 247         Watch *w;
 248         int r;
 249
 250         assert(timeout);
 251         assert(m);
 252
 253         assert_se(w = dbus_timeout_get_data(timeout));
 254         assert(w->type == WATCH_DBUS_TIMEOUT);
 255
 256         if ((r = bus_timeout_arm(m, w)) < 0)
 257                 log_error("Failed to rearm timer: %s", strerror(-r));
 258 }
 259
 260 void bus_dispatch(Manager *m) {
 261         assert(m);
 262
 263         if (dbus_connection_dispatch(m->bus) == DBUS_DISPATCH_COMPLETE)
 264                 m->request_bus_dispatch = false;
 265 }
 266
 267 static int request_name(Manager *m) {
 268         DBusMessage *message;
 269         const char *name = "org.freedesktop.systemd1";
 270         uint32_t flags = 0;
 271
 272         if (!(message = dbus_message_new_method_call(
 273                               DBUS_SERVICE_DBUS,
 274                               DBUS_PATH_DBUS,
 275                               DBUS_INTERFACE_DBUS,
 276                               "RequestName")))
 277                 return -ENOMEM;
 278
 279         if (!dbus_message_append_args(
 280                             message,
 281                             DBUS_TYPE_STRING, &name,
 282                             DBUS_TYPE_UINT32, &flags,
 283                             DBUS_TYPE_INVALID)) {
 284                 dbus_message_unref(message);
 285                 return -ENOMEM;
 286         }
 287
 288         if (!dbus_connection_send(m->bus, message, NULL)) {
 289                 dbus_message_unref(message);
 290                 return -ENOMEM;
 291         }
 292
 293         /* We simple ask for the name and don't wait for it. Sooner or
 294          * later we'll have it, and we wouldn't know what to do on
 295          * error anyway. */
 296
 297         dbus_message_unref(message);
 298
 299         return 0;
 300 }
 301
 302 int bus_init(Manager *m) {
 303         DBusError error;
 304         char *id;
 305         int r;
 306
 307         assert(m);
 308
 309         if (m->bus)
 310                 return 0;
 311
 312         dbus_connection_set_change_sigpipe(FALSE);
 313
 314         dbus_error_init(&error);
 315         if (!(m->bus = dbus_bus_get_private(m->is_init ? DBUS_BUS_SYSTEM : DBUS_BUS_SESSION, &error))) {
 316                 log_error("Failed to get D-Bus connection: %s", error.message);
 317                 dbus_error_free(&error);
 318                 return -ECONNREFUSED;
 319         }
 320
 321         dbus_connection_set_exit_on_disconnect(m->bus, FALSE);
 322         dbus_connection_set_dispatch_status_function(m->bus, bus_dispatch_status, m, NULL);
 323         if (!dbus_connection_set_watch_functions(m->bus, bus_add_watch, bus_remove_watch, bus_toggle_watch, m, NULL) ||
 324             !dbus_connection_set_timeout_functions(m->bus, bus_add_timeout, bus_remove_timeout, bus_toggle_timeout, m, NULL) ||
 325             !dbus_connection_register_object_path(m->bus, "/org/freedesktop/systemd1", &bus_manager_vtable, m) ||
 326             !dbus_connection_register_fallback(m->bus, "/org/freedesktop/systemd1/unit", &bus_unit_vtable, m) ||
 327             !dbus_connection_register_fallback(m->bus, "/org/freedesktop/systemd1/job", &bus_job_vtable, m)) {
 328                 bus_done(m);
 329                 return -ENOMEM;
 330         }
 331
 332         if ((r = request_name(m)) < 0) {
 333                 bus_done(m);
 334                 return r;
 335         }
 336
 337         log_debug("Successfully connected to D-Bus bus %s as %s",
 338                   strnull((id = dbus_connection_get_server_id(m->bus))),
 339                   strnull(dbus_bus_get_unique_name(m->bus)));
 340         dbus_free(id);
 341
 342         m->request_bus_dispatch = true;
 343
 344         return 0;
 345 }
 346
 347 void bus_done(Manager *m) {
 348         assert(m);
 349
 350         if (m->bus) {
 351                 dbus_connection_close(m->bus);
 352                 dbus_connection_unref(m->bus);
 353                 m->bus = NULL;
 354         }
 355 }
 356
 357 DBusHandlerResult bus_default_message_handler(Manager *m, DBusMessage *message, const char*introspection, const BusProperty *properties) {
 358         DBusError error;
 359         DBusMessage *reply = NULL;
 360         int r;
 361
 362         assert(m);
 363         assert(message);
 364
 365         dbus_error_init(&error);
 366
 367         if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Introspectable", "Introspect") && introspection) {
 368
 369                 if (!(reply = dbus_message_new_method_return(message)))
 370                         goto oom;
 371
 372                 if (!dbus_message_append_args(reply, DBUS_TYPE_STRING, &introspection, DBUS_TYPE_INVALID))
 373                         goto oom;
 374
 375         } else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Properties", "Get") && properties) {
 376                 const char *interface, *property;
 377                 const BusProperty *p;
 378
 379                 if (!dbus_message_get_args(
 380                             message,
 381                             &error,
 382                             DBUS_TYPE_STRING, &interface,
 383                             DBUS_TYPE_STRING, &property,
 384                             DBUS_TYPE_INVALID))
 385                         return bus_send_error_reply(m, message, &error, -EINVAL);
 386
 387                 for (p = properties; p->property; p++)
 388                         if (streq(p->interface, interface) && streq(p->property, property))
 389                                 break;
 390
 391                 if (p->property) {
 392                         DBusMessageIter iter, sub;
 393
 394                         if (!(reply = dbus_message_new_method_return(message)))
 395                                 goto oom;
 396
 397                         dbus_message_iter_init_append(reply, &iter);
 398
 399                         if (!dbus_message_iter_open_container(&iter, DBUS_TYPE_VARIANT, p->signature, &sub))
 400                                 goto oom;
 401
 402                         if ((r = p->append(m, &sub, property, p->data)) < 0) {
 403
 404                                 if (r == -ENOMEM)
 405                                         goto oom;
 406
 407                                 dbus_message_unref(reply);
 408                                 return bus_send_error_reply(m, message, NULL, r);
 409                         }
 410
 411                         if (!dbus_message_iter_close_container(&iter, &sub))
 412                                 goto oom;
 413                 }
 414         } else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Properties", "GetAll") && properties) {
 415                 const char *interface;
 416                 const BusProperty *p;
 417                 DBusMessageIter iter, sub, sub2, sub3;
 418                 bool any = false;
 419
 420                 if (!dbus_message_get_args(
 421                             message,
 422                             &error,
 423                             DBUS_TYPE_STRING, &interface,
 424                             DBUS_TYPE_INVALID))
 425                         return bus_send_error_reply(m, message, &error, -EINVAL);
 426
 427                 if (!(reply = dbus_message_new_method_return(message)))
 428                         goto oom;
 429
 430                 dbus_message_iter_init_append(reply, &iter);
 431
 432                 if (!dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "{sv}", &sub))
 433                         goto oom;
 434
 435                 for (p = properties; p->property; p++) {
 436                         if (!streq(p->interface, interface))
 437                                 continue;
 438
 439                         if (!dbus_message_iter_open_container(&sub, DBUS_TYPE_DICT_ENTRY, NULL, &sub2) ||
 440                             !dbus_message_iter_append_basic(&sub2, DBUS_TYPE_STRING, &p->property) ||
 441                             !dbus_message_iter_open_container(&sub2, DBUS_TYPE_VARIANT, p->signature, &sub3))
 442                                 goto oom;
 443
 444                         if ((r = p->append(m, &sub3, p->property, p->data)) < 0) {
 445
 446                                 if (r == -ENOMEM)
 447                                         goto oom;
 448
 449                                 dbus_message_unref(reply);
 450                                 return bus_send_error_reply(m, message, NULL, r);
 451                         }
 452
 453                         if (!dbus_message_iter_close_container(&sub2, &sub3) ||
 454                             !dbus_message_iter_close_container(&sub, &sub2))
 455                                 goto oom;
 456
 457                         any = true;
 458                 }
 459
 460                 if (!dbus_message_iter_close_container(&iter, &sub))
 461                         goto oom;
 462         }
 463
 464         if (reply) {
 465                 if (!dbus_connection_send(m->bus, reply, NULL))
 466                         goto oom;
 467
 468                 dbus_message_unref(reply);
 469                 return DBUS_HANDLER_RESULT_HANDLED;
 470         }
 471
 472         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 473
 474 oom:
 475         if (reply)
 476                 dbus_message_unref(reply);
 477
 478         dbus_error_free(&error);
 479
 480         return DBUS_HANDLER_RESULT_NEED_MEMORY;
 481 }
 482
 483
 484
 485 static const char *error_to_dbus(int error) {
 486
 487         switch(error) {
 488
 489         case -EINVAL:
 490                 return DBUS_ERROR_INVALID_ARGS;
 491
 492         case -ENOMEM:
 493                 return DBUS_ERROR_NO_MEMORY;
 494
 495         case -EPERM:
 496         case -EACCES:
 497                 return DBUS_ERROR_ACCESS_DENIED;
 498
 499         case -ESRCH:
 500                 return DBUS_ERROR_UNIX_PROCESS_ID_UNKNOWN;
 501
 502         case -ENOENT:
 503                 return DBUS_ERROR_FILE_NOT_FOUND;
 504
 505         case -EEXIST:
 506                 return DBUS_ERROR_FILE_EXISTS;
 507
 508         case -ETIMEDOUT:
 509                 return DBUS_ERROR_TIMEOUT;
 510
 511         case -EIO:
 512                 return DBUS_ERROR_IO_ERROR;
 513
 514         case -ENETRESET:
 515         case -ECONNABORTED:
 516         case -ECONNRESET:
 517                 return DBUS_ERROR_DISCONNECTED;
 518         }
 519
 520         return DBUS_ERROR_FAILED;
 521 }
 522
 523 DBusHandlerResult bus_send_error_reply(Manager *m, DBusMessage *message, DBusError *bus_error, int error) {
 524         DBusMessage *reply = NULL;
 525         const char *name, *text;
 526
 527         if (bus_error && dbus_error_is_set(bus_error)) {
 528                 name = bus_error->name;
 529                 text = bus_error->message;
 530         } else {
 531                 name = error_to_dbus(error);
 532                 text = strerror(-error);
 533         }
 534
 535         if (!(reply = dbus_message_new_error(message, name, text)))
 536                 goto oom;
 537
 538         if (!dbus_connection_send(m->bus, reply, NULL))
 539                 goto oom;
 540
 541         dbus_message_unref(reply);
 542
 543         if (bus_error)
 544                 dbus_error_free(bus_error);
 545
 546         return DBUS_HANDLER_RESULT_HANDLED;
 547
 548 oom:
 549         if (reply)
 550                 dbus_message_unref(reply);
 551
 552         if (bus_error)
 553                 dbus_error_free(bus_error);
 554
 555         return DBUS_HANDLER_RESULT_NEED_MEMORY;
 556 }
 557
 558 int bus_property_append_string(Manager *m, DBusMessageIter *i, const char *property, void *data) {
 559         const char *t = data;
 560
 561         assert(m);
 562         assert(i);
 563         assert(property);
 564
 565         if (!t)
 566                 t = "";
 567
 568         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_STRING, &t))
 569                 return -ENOMEM;
 570
 571         return 0;
 572 }
 573
 574 int bus_property_append_strv(Manager *m, DBusMessageIter *i, const char *property, void *data) {
 575         DBusMessageIter sub;
 576         char **t = data;
 577
 578         assert(m);
 579         assert(i);
 580         assert(property);
 581
 582         if (!dbus_message_iter_open_container(i, DBUS_TYPE_ARRAY, "s", &sub))
 583                 return -ENOMEM;
 584
 585         STRV_FOREACH(t, t)
 586                 if (!dbus_message_iter_append_basic(&sub, DBUS_TYPE_STRING, t))
 587                         return -ENOMEM;
 588
 589         if (!dbus_message_iter_close_container(i, &sub))
 590                 return -ENOMEM;
 591
 592         return 0;
 593 }
 594
 595 int bus_property_append_bool(Manager *m, DBusMessageIter *i, const char *property, void *data) {
 596         bool *b = data;
 597         dbus_bool_t db;
 598
 599         assert(m);
 600         assert(i);
 601         assert(property);
 602         assert(b);
 603
 604         db = *b;
 605
 606         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_BOOLEAN, &db))
 607                 return -ENOMEM;
 608
 609         return 0;
 610 }
 611
 612 int bus_property_append_uint64(Manager *m, DBusMessageIter *i, const char *property, void *data) {
 613         assert(m);
 614         assert(i);
 615         assert(property);
 616         assert(data);
 617
 618         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT64, data))
 619                 return -ENOMEM;
 620
 621         return 0;
 622 }
 623
 624 int bus_property_append_uint32(Manager *m, DBusMessageIter *i, const char *property, void *data) {
 625         assert(m);
 626         assert(i);
 627         assert(property);
 628         assert(data);
 629
 630         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT32, data))
 631                 return -ENOMEM;
 632
 633         return 0;
 634 }