src/dbus-common.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   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   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <assert.h>
  23 #include <sys/socket.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <dbus/dbus.h>
  29 #include <string.h>
  30
  31 #include "log.h"
  32 #include "dbus-common.h"
  33 #include "util.h"
  34 #include "def.h"
  35 #include "strv.h"
  36
  37 int bus_check_peercred(DBusConnection *c) {
  38         int fd;
  39         struct ucred ucred;
  40         socklen_t l;
  41
  42         assert(c);
  43
  44         assert_se(dbus_connection_get_unix_fd(c, &fd));
  45
  46         l = sizeof(struct ucred);
  47         if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &l) < 0) {
  48                 log_error("SO_PEERCRED failed: %m");
  49                 return -errno;
  50         }
  51
  52         if (l != sizeof(struct ucred)) {
  53                 log_error("SO_PEERCRED returned wrong size.");
  54                 return -E2BIG;
  55         }
  56
  57         if (ucred.uid != 0)
  58                 return -EPERM;
  59
  60         return 1;
  61 }
  62
  63 static int sync_auth(DBusConnection *bus, DBusError *error) {
  64         usec_t begin, tstamp;
  65
  66         assert(bus);
  67
  68         /* This complexity should probably move into D-Bus itself:
  69          *
  70          * https://bugs.freedesktop.org/show_bug.cgi?id=35189 */
  71
  72         begin = tstamp = now(CLOCK_MONOTONIC);
  73         for (;;) {
  74
  75                 if (tstamp > begin + DEFAULT_TIMEOUT_USEC)
  76                         break;
  77
  78                 if (dbus_connection_get_is_authenticated(bus))
  79                         break;
  80
  81                 if (!dbus_connection_read_write_dispatch(bus, ((begin + DEFAULT_TIMEOUT_USEC - tstamp) + USEC_PER_MSEC - 1) / USEC_PER_MSEC))
  82                         break;
  83
  84                 tstamp = now(CLOCK_MONOTONIC);
  85         }
  86
  87         if (!dbus_connection_get_is_connected(bus)) {
  88                 dbus_set_error_const(error, DBUS_ERROR_NO_SERVER, "Connection terminated during authentication.");
  89                 return -ECONNREFUSED;
  90         }
  91
  92         if (!dbus_connection_get_is_authenticated(bus)) {
  93                 dbus_set_error_const(error, DBUS_ERROR_TIMEOUT, "Failed to authenticate in time.");
  94                 return -EACCES;
  95         }
  96
  97         return 0;
  98 }
  99
 100 int bus_connect(DBusBusType t, DBusConnection **_bus, bool *private, DBusError *error) {
 101         DBusConnection *bus;
 102         int r;
 103
 104         assert(_bus);
 105
 106         /* If we are root, then let's not go via the bus */
 107         if (geteuid() == 0 && t == DBUS_BUS_SYSTEM) {
 108
 109                 if (!(bus = dbus_connection_open_private("unix:path=/run/systemd/private", error))) {
 110 #ifndef LEGACY
 111                         dbus_error_free(error);
 112
 113                         /* Retry with the pre v21 socket name, to ease upgrades */
 114                         if (!(bus = dbus_connection_open_private("unix:abstract=/org/freedesktop/systemd1/private", error)))
 115 #endif
 116                                 return -EIO;
 117                 }
 118
 119                 dbus_connection_set_exit_on_disconnect(bus, FALSE);
 120
 121                 if (bus_check_peercred(bus) < 0) {
 122                         dbus_connection_close(bus);
 123                         dbus_connection_unref(bus);
 124
 125                         dbus_set_error_const(error, DBUS_ERROR_ACCESS_DENIED, "Failed to verify owner of bus.");
 126                         return -EACCES;
 127                 }
 128
 129                 if (private)
 130                         *private = true;
 131
 132         } else {
 133                 if (!(bus = dbus_bus_get_private(t, error)))
 134                         return -EIO;
 135
 136                 dbus_connection_set_exit_on_disconnect(bus, FALSE);
 137
 138                 if (private)
 139                         *private = false;
 140         }
 141
 142         if ((r = sync_auth(bus, error)) < 0) {
 143                 dbus_connection_close(bus);
 144                 dbus_connection_unref(bus);
 145                 return r;
 146         }
 147
 148         *_bus = bus;
 149         return 0;
 150 }
 151
 152 int bus_connect_system_ssh(const char *user, const char *host, DBusConnection **_bus, DBusError *error) {
 153         DBusConnection *bus;
 154         char *p = NULL;
 155         int r;
 156
 157         assert(_bus);
 158         assert(user || host);
 159
 160         if (user && host)
 161                 asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s@%s,argv3=systemd-stdio-bridge", user, host);
 162         else if (user)
 163                 asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s@localhost,argv3=systemd-stdio-bridge", user);
 164         else if (host)
 165                 asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s,argv3=systemd-stdio-bridge", host);
 166
 167         if (!p) {
 168                 dbus_set_error_const(error, DBUS_ERROR_NO_MEMORY, NULL);
 169                 return -ENOMEM;
 170         }
 171
 172         bus = dbus_connection_open_private(p, error);
 173         free(p);
 174
 175         if (!bus)
 176                 return -EIO;
 177
 178         dbus_connection_set_exit_on_disconnect(bus, FALSE);
 179
 180         if ((r = sync_auth(bus, error)) < 0) {
 181                 dbus_connection_close(bus);
 182                 dbus_connection_unref(bus);
 183                 return r;
 184         }
 185
 186         if (!dbus_bus_register(bus, error)) {
 187                 dbus_connection_close(bus);
 188                 dbus_connection_unref(bus);
 189                 return r;
 190         }
 191
 192         *_bus = bus;
 193         return 0;
 194 }
 195
 196 int bus_connect_system_polkit(DBusConnection **_bus, DBusError *error) {
 197         DBusConnection *bus;
 198         int r;
 199
 200         assert(_bus);
 201
 202         /* Don't bother with PolicyKit if we are root */
 203         if (geteuid() == 0)
 204                 return bus_connect(DBUS_BUS_SYSTEM, _bus, NULL, error);
 205
 206         if (!(bus = dbus_connection_open_private("exec:path=pkexec,argv1=" SYSTEMD_STDIO_BRIDGE_BINARY_PATH, error)))
 207                 return -EIO;
 208
 209         dbus_connection_set_exit_on_disconnect(bus, FALSE);
 210
 211         if ((r = sync_auth(bus, error)) < 0) {
 212                 dbus_connection_close(bus);
 213                 dbus_connection_unref(bus);
 214                 return r;
 215         }
 216
 217         if (!dbus_bus_register(bus, error)) {
 218                 dbus_connection_close(bus);
 219                 dbus_connection_unref(bus);
 220                 return r;
 221         }
 222
 223         *_bus = bus;
 224         return 0;
 225 }
 226
 227 const char *bus_error_message(const DBusError *error) {
 228         assert(error);
 229
 230         /* Sometimes the D-Bus server is a little bit too verbose with
 231          * its error messages, so let's override them here */
 232         if (dbus_error_has_name(error, DBUS_ERROR_ACCESS_DENIED))
 233                 return "Access denied";
 234
 235         return error->message;
 236 }
 237
 238 DBusHandlerResult bus_default_message_handler(
 239                 DBusConnection *c,
 240                 DBusMessage *message,
 241                 const char *introspection,
 242                 const char *interfaces,
 243                 const BusProperty *properties) {
 244
 245         DBusError error;
 246         DBusMessage *reply = NULL;
 247         int r;
 248
 249         assert(c);
 250         assert(message);
 251
 252         dbus_error_init(&error);
 253
 254         if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Introspectable", "Introspect") && introspection) {
 255
 256                 if (!(reply = dbus_message_new_method_return(message)))
 257                         goto oom;
 258
 259                 if (!dbus_message_append_args(reply, DBUS_TYPE_STRING, &introspection, DBUS_TYPE_INVALID))
 260                         goto oom;
 261
 262         } else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Properties", "Get") && properties) {
 263                 const char *interface, *property;
 264                 const BusProperty *p;
 265
 266                 if (!dbus_message_get_args(
 267                             message,
 268                             &error,
 269                             DBUS_TYPE_STRING, &interface,
 270                             DBUS_TYPE_STRING, &property,
 271                             DBUS_TYPE_INVALID))
 272                         return bus_send_error_reply(c, message, &error, -EINVAL);
 273
 274                 for (p = properties; p->property; p++)
 275                         if (streq(p->interface, interface) && streq(p->property, property))
 276                                 break;
 277
 278                 if (p->property) {
 279                         DBusMessageIter iter, sub;
 280
 281                         if (!(reply = dbus_message_new_method_return(message)))
 282                                 goto oom;
 283
 284                         dbus_message_iter_init_append(reply, &iter);
 285
 286                         if (!dbus_message_iter_open_container(&iter, DBUS_TYPE_VARIANT, p->signature, &sub))
 287                                 goto oom;
 288
 289                         if ((r = p->append(&sub, property, (void*) p->data)) < 0) {
 290
 291                                 if (r == -ENOMEM)
 292                                         goto oom;
 293
 294                                 dbus_message_unref(reply);
 295                                 return bus_send_error_reply(c, message, NULL, r);
 296                         }
 297
 298                         if (!dbus_message_iter_close_container(&iter, &sub))
 299                                 goto oom;
 300                 } else {
 301                         if (!nulstr_contains(interfaces, interface))
 302                                 dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
 303                         else
 304                                 dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_PROPERTY, "Unknown property");
 305
 306                         return bus_send_error_reply(c, message, &error, -EINVAL);
 307                 }
 308
 309         } else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Properties", "GetAll") && properties) {
 310                 const char *interface;
 311                 const BusProperty *p;
 312                 DBusMessageIter iter, sub, sub2, sub3;
 313
 314                 if (!dbus_message_get_args(
 315                             message,
 316                             &error,
 317                             DBUS_TYPE_STRING, &interface,
 318                             DBUS_TYPE_INVALID))
 319                         return bus_send_error_reply(c, message, &error, -EINVAL);
 320
 321                 if (interface[0] && !nulstr_contains(interfaces, interface)) {
 322                         dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
 323                         return bus_send_error_reply(c, message, &error, -EINVAL);
 324                 }
 325
 326                 if (!(reply = dbus_message_new_method_return(message)))
 327                         goto oom;
 328
 329                 dbus_message_iter_init_append(reply, &iter);
 330
 331                 if (!dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "{sv}", &sub))
 332                         goto oom;
 333
 334                 for (p = properties; p->property; p++) {
 335                         if (interface[0] && !streq(p->interface, interface))
 336                                 continue;
 337
 338                         if (!dbus_message_iter_open_container(&sub, DBUS_TYPE_DICT_ENTRY, NULL, &sub2) ||
 339                             !dbus_message_iter_append_basic(&sub2, DBUS_TYPE_STRING, &p->property) ||
 340                             !dbus_message_iter_open_container(&sub2, DBUS_TYPE_VARIANT, p->signature, &sub3))
 341                                 goto oom;
 342
 343                         if ((r = p->append(&sub3, p->property, (void*) p->data)) < 0) {
 344
 345                                 if (r == -ENOMEM)
 346                                         goto oom;
 347
 348                                 dbus_message_unref(reply);
 349                                 return bus_send_error_reply(c, message, NULL, r);
 350                         }
 351
 352                         if (!dbus_message_iter_close_container(&sub2, &sub3) ||
 353                             !dbus_message_iter_close_container(&sub, &sub2))
 354                                 goto oom;
 355                 }
 356
 357                 if (!dbus_message_iter_close_container(&iter, &sub))
 358                         goto oom;
 359
 360         } else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Properties", "Set") && properties) {
 361                 const char *interface, *property;
 362                 DBusMessageIter iter;
 363                 const BusProperty *p;
 364
 365                 if (!dbus_message_iter_init(message, &iter) ||
 366                     dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_STRING)
 367                         return bus_send_error_reply(c, message, NULL, -EINVAL);
 368
 369                 dbus_message_iter_get_basic(&iter, &interface);
 370
 371                 if (!dbus_message_iter_next(&iter) ||
 372                     dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_STRING)
 373                         return bus_send_error_reply(c, message, NULL, -EINVAL);
 374
 375                 dbus_message_iter_get_basic(&iter, &property);
 376
 377                 if (!dbus_message_iter_next(&iter) ||
 378                     dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_VARIANT ||
 379                     dbus_message_iter_has_next(&iter))
 380                         return bus_send_error_reply(c, message, NULL, -EINVAL);
 381
 382                 for (p = properties; p->property; p++)
 383                         if (streq(p->interface, interface) && streq(p->property, property))
 384                                 break;
 385
 386                 if (p->set) {
 387                         DBusMessageIter sub;
 388                         char *sig;
 389
 390                         dbus_message_iter_recurse(&iter, &sub);
 391
 392                         if (!(sig = dbus_message_iter_get_signature(&sub)))
 393                                 goto oom;
 394
 395                         if (!streq(sig, p->signature)) {
 396                                 dbus_free(sig);
 397                                 return bus_send_error_reply(c, message, NULL, -EINVAL);
 398                         }
 399
 400                         dbus_free(sig);
 401
 402                         if ((r = p->set(&sub, property)) < 0) {
 403                                 if (r == -ENOMEM)
 404                                         goto oom;
 405                                 return bus_send_error_reply(c, message, NULL, r);
 406                         }
 407
 408                         if (!(reply = dbus_message_new_method_return(message)))
 409                                 goto oom;
 410                 } else {
 411                         if (p->property)
 412                                 dbus_set_error_const(&error, DBUS_ERROR_PROPERTY_READ_ONLY, "Property read-only");
 413                         else if (!nulstr_contains(interfaces, interface))
 414                                 dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
 415                         else
 416                                 dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_PROPERTY, "Unknown property");
 417
 418                         return bus_send_error_reply(c, message, &error, -EINVAL);
 419                 }
 420
 421         } else {
 422                 const char *interface = dbus_message_get_interface(message);
 423
 424                 if (!interface || !nulstr_contains(interfaces, interface)) {
 425                         dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
 426                         return bus_send_error_reply(c, message, &error, -EINVAL);
 427                 }
 428         }
 429
 430         if (reply) {
 431                 if (!dbus_connection_send(c, reply, NULL))
 432                         goto oom;
 433
 434                 dbus_message_unref(reply);
 435                 return DBUS_HANDLER_RESULT_HANDLED;
 436         }
 437
 438         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 439
 440 oom:
 441         if (reply)
 442                 dbus_message_unref(reply);
 443
 444         dbus_error_free(&error);
 445
 446         return DBUS_HANDLER_RESULT_NEED_MEMORY;
 447 }
 448
 449 int bus_property_append_string(DBusMessageIter *i, const char *property, void *data) {
 450         const char *t = data;
 451
 452         assert(i);
 453         assert(property);
 454
 455         if (!t)
 456                 t = "";
 457
 458         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_STRING, &t))
 459                 return -ENOMEM;
 460
 461         return 0;
 462 }
 463
 464 int bus_property_append_strv(DBusMessageIter *i, const char *property, void *data) {
 465         DBusMessageIter sub;
 466         char **t = data;
 467
 468         assert(i);
 469         assert(property);
 470
 471         if (!dbus_message_iter_open_container(i, DBUS_TYPE_ARRAY, "s", &sub))
 472                 return -ENOMEM;
 473
 474         STRV_FOREACH(t, t)
 475                 if (!dbus_message_iter_append_basic(&sub, DBUS_TYPE_STRING, t))
 476                         return -ENOMEM;
 477
 478         if (!dbus_message_iter_close_container(i, &sub))
 479                 return -ENOMEM;
 480
 481         return 0;
 482 }
 483
 484 int bus_property_append_bool(DBusMessageIter *i, const char *property, void *data) {
 485         bool *b = data;
 486         dbus_bool_t db;
 487
 488         assert(i);
 489         assert(property);
 490         assert(b);
 491
 492         db = *b;
 493
 494         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_BOOLEAN, &db))
 495                 return -ENOMEM;
 496
 497         return 0;
 498 }
 499
 500 int bus_property_append_uint64(DBusMessageIter *i, const char *property, void *data) {
 501         assert(i);
 502         assert(property);
 503         assert(data);
 504
 505         /* Let's ensure that pid_t is actually 64bit, and hence this
 506          * function can be used for usec_t */
 507         assert_cc(sizeof(uint64_t) == sizeof(usec_t));
 508
 509         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT64, data))
 510                 return -ENOMEM;
 511
 512         return 0;
 513 }
 514
 515 int bus_property_append_uint32(DBusMessageIter *i, const char *property, void *data) {
 516         assert(i);
 517         assert(property);
 518         assert(data);
 519
 520         /* Let's ensure that pid_t and mode_t is actually 32bit, and
 521          * hence this function can be used for pid_t/mode_t */
 522         assert_cc(sizeof(uint32_t) == sizeof(pid_t));
 523         assert_cc(sizeof(uint32_t) == sizeof(mode_t));
 524         assert_cc(sizeof(uint32_t) == sizeof(unsigned));
 525
 526         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT32, data))
 527                 return -ENOMEM;
 528
 529         return 0;
 530 }
 531
 532 int bus_property_append_int32(DBusMessageIter *i, const char *property, void *data) {
 533         assert(i);
 534         assert(property);
 535         assert(data);
 536
 537         assert_cc(sizeof(int32_t) == sizeof(int));
 538
 539         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_INT32, data))
 540                 return -ENOMEM;
 541
 542         return 0;
 543 }
 544
 545 int bus_property_append_size(DBusMessageIter *i, const char *property, void *data) {
 546         uint64_t u;
 547
 548         assert(i);
 549         assert(property);
 550         assert(data);
 551
 552         u = (uint64_t) *(size_t*) data;
 553
 554         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT64, &u))
 555                 return -ENOMEM;
 556
 557         return 0;
 558 }
 559
 560 int bus_property_append_ul(DBusMessageIter *i, const char *property, void *data) {
 561         uint64_t u;
 562
 563         assert(i);
 564         assert(property);
 565         assert(data);
 566
 567         u = (uint64_t) *(unsigned long*) data;
 568
 569         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT64, &u))
 570                 return -ENOMEM;
 571
 572         return 0;
 573 }
 574
 575 int bus_property_append_long(DBusMessageIter *i, const char *property, void *data) {
 576         int64_t l;
 577
 578         assert(i);
 579         assert(property);
 580         assert(data);
 581
 582         l = (int64_t) *(long*) data;
 583
 584         if (!dbus_message_iter_append_basic(i, DBUS_TYPE_INT64, &l))
 585                 return -ENOMEM;
 586
 587         return 0;
 588 }
 589
 590 const char *bus_errno_to_dbus(int error) {
 591
 592         switch(error) {
 593
 594         case -EINVAL:
 595                 return DBUS_ERROR_INVALID_ARGS;
 596
 597         case -ENOMEM:
 598                 return DBUS_ERROR_NO_MEMORY;
 599
 600         case -EPERM:
 601         case -EACCES:
 602                 return DBUS_ERROR_ACCESS_DENIED;
 603
 604         case -ESRCH:
 605                 return DBUS_ERROR_UNIX_PROCESS_ID_UNKNOWN;
 606
 607         case -ENOENT:
 608                 return DBUS_ERROR_FILE_NOT_FOUND;
 609
 610         case -EEXIST:
 611                 return DBUS_ERROR_FILE_EXISTS;
 612
 613         case -ETIMEDOUT:
 614         case -ETIME:
 615                 return DBUS_ERROR_TIMEOUT;
 616
 617         case -EIO:
 618                 return DBUS_ERROR_IO_ERROR;
 619
 620         case -ENETRESET:
 621         case -ECONNABORTED:
 622         case -ECONNRESET:
 623                 return DBUS_ERROR_DISCONNECTED;
 624         }
 625
 626         return DBUS_ERROR_FAILED;
 627 }
 628
 629 DBusHandlerResult bus_send_error_reply(DBusConnection *c, DBusMessage *message, DBusError *berror, int error) {
 630         DBusMessage *reply = NULL;
 631         const char *name, *text;
 632
 633         if (berror && dbus_error_is_set(berror)) {
 634                 name = berror->name;
 635                 text = berror->message;
 636         } else {
 637                 name = bus_errno_to_dbus(error);
 638                 text = strerror(-error);
 639         }
 640
 641         if (!(reply = dbus_message_new_error(message, name, text)))
 642                 goto oom;
 643
 644         if (!dbus_connection_send(c, reply, NULL))
 645                 goto oom;
 646
 647         dbus_message_unref(reply);
 648
 649         if (berror)
 650                 dbus_error_free(berror);
 651
 652         return DBUS_HANDLER_RESULT_HANDLED;
 653
 654 oom:
 655         if (reply)
 656                 dbus_message_unref(reply);
 657
 658         if (berror)
 659                 dbus_error_free(berror);
 660
 661         return DBUS_HANDLER_RESULT_NEED_MEMORY;
 662 }
 663
 664 DBusMessage* bus_properties_changed_new(const char *path, const char *interface, const char *properties) {
 665         DBusMessage *m;
 666         DBusMessageIter iter, sub;
 667         const char *i;
 668
 669         assert(interface);
 670         assert(properties);
 671
 672         if (!(m = dbus_message_new_signal(path, "org.freedesktop.DBus.Properties", "PropertiesChanged")))
 673                 goto oom;
 674
 675         dbus_message_iter_init_append(m, &iter);
 676
 677         /* We won't send any property values, since they might be
 678          * large and sometimes not cheap to generated */
 679
 680         if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &interface) ||
 681             !dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "{sv}", &sub) ||
 682             !dbus_message_iter_close_container(&iter, &sub) ||
 683             !dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "s", &sub))
 684                 goto oom;
 685
 686         NULSTR_FOREACH(i, properties)
 687                 if (!dbus_message_iter_append_basic(&sub, DBUS_TYPE_STRING, &i))
 688                         goto oom;
 689
 690         if (!dbus_message_iter_close_container(&iter, &sub))
 691                 goto oom;
 692
 693         return m;
 694
 695 oom:
 696         if (m)
 697                 dbus_message_unref(m);
 698
 699         return NULL;
 700 }