src/shared/bus-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <inttypes.h>
   6 #include <stdlib.h>
   7 #include <sys/ioctl.h>
   8 #include <sys/resource.h>
   9 #include <sys/socket.h>
  10 #include <unistd.h>
  11
  12 #include "sd-bus.h"
  13 #include "sd-daemon.h"
  14 #include "sd-event.h"
  15 #include "sd-id128.h"
  16
  17 #include "bus-common-errors.h"
  18 #include "bus-internal.h"
  19 #include "bus-label.h"
  20 #include "bus-util.h"
  21 #include "daemon-util.h"
  22 #include "data-fd-util.h"
  23 #include "fd-util.h"
  24 #include "memstream-util.h"
  25 #include "path-util.h"
  26 #include "socket-util.h"
  27 #include "stdio-util.h"
  28
  29 static int name_owner_change_callback(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
  30         sd_event *e = ASSERT_PTR(userdata);
  31
  32         assert(m);
  33
  34         sd_bus_close(sd_bus_message_get_bus(m));
  35         sd_event_exit(e, 0);
  36
  37         return 1;
  38 }
  39
  40 int bus_log_address_error(int r, BusTransport transport) {
  41         bool hint = transport == BUS_TRANSPORT_LOCAL && r == -ENOMEDIUM;
  42
  43         return log_error_errno(r,
  44                                hint ? "Failed to set bus address: $DBUS_SESSION_BUS_ADDRESS and $XDG_RUNTIME_DIR not defined (consider using --machine=<user>@.host --user to connect to bus of other user)" :
  45                                       "Failed to set bus address: %m");
  46 }
  47
  48 int bus_log_connect_error(int r, BusTransport transport) {
  49         bool hint_vars = transport == BUS_TRANSPORT_LOCAL && r == -ENOMEDIUM,
  50              hint_addr = transport == BUS_TRANSPORT_LOCAL && ERRNO_IS_PRIVILEGE(r);
  51
  52         return log_error_errno(r,
  53                                r == hint_vars ? "Failed to connect to bus: $DBUS_SESSION_BUS_ADDRESS and $XDG_RUNTIME_DIR not defined (consider using --machine=<user>@.host --user to connect to bus of other user)" :
  54                                r == hint_addr ? "Failed to connect to bus: Operation not permitted (consider using --machine=<user>@.host --user to connect to bus of other user)" :
  55                                                 "Failed to connect to bus: %m");
  56 }
  57
  58 int bus_async_unregister_and_exit(sd_event *e, sd_bus *bus, const char *name) {
  59         const char *match;
  60         const char *unique;
  61         int r;
  62
  63         assert(e);
  64         assert(bus);
  65         assert(name);
  66
  67         /* We unregister the name here and then wait for the
  68          * NameOwnerChanged signal for this event to arrive before we
  69          * quit. We do this in order to make sure that any queued
  70          * requests are still processed before we really exit. */
  71
  72         r = sd_bus_get_unique_name(bus, &unique);
  73         if (r < 0)
  74                 return r;
  75
  76         match = strjoina(
  77                         "sender='org.freedesktop.DBus',"
  78                         "type='signal',"
  79                         "interface='org.freedesktop.DBus',"
  80                         "member='NameOwnerChanged',"
  81                         "path='/org/freedesktop/DBus',"
  82                         "arg0='", name, "',",
  83                         "arg1='", unique, "',",
  84                         "arg2=''");
  85
  86         r = sd_bus_add_match_async(bus, NULL, match, name_owner_change_callback, NULL, e);
  87         if (r < 0)
  88                 return r;
  89
  90         r = sd_bus_release_name_async(bus, NULL, name, NULL, NULL);
  91         if (r < 0)
  92                 return r;
  93
  94         return 0;
  95 }
  96
  97 int bus_event_loop_with_idle(
  98                 sd_event *e,
  99                 sd_bus *bus,
 100                 const char *name,
 101                 usec_t timeout,
 102                 check_idle_t check_idle,
 103                 void *userdata) {
 104
 105         bool exiting = false;
 106         int r, code;
 107
 108         assert(e);
 109         assert(bus);
 110         assert(name);
 111
 112         for (;;) {
 113                 bool idle;
 114
 115                 r = sd_event_get_state(e);
 116                 if (r < 0)
 117                         return r;
 118                 if (r == SD_EVENT_FINISHED)
 119                         break;
 120
 121                 if (check_idle)
 122                         idle = check_idle(userdata);
 123                 else
 124                         idle = true;
 125
 126                 r = sd_event_run(e, exiting || !idle ? UINT64_MAX : timeout);
 127                 if (r < 0)
 128                         return r;
 129
 130                 if (r == 0 && !exiting && idle) {
 131                         /* Inform the service manager that we are going down, so that it will queue all
 132                          * further start requests, instead of assuming we are still running. */
 133                         (void) sd_notify(false, NOTIFY_STOPPING);
 134
 135                         r = bus_async_unregister_and_exit(e, bus, name);
 136                         if (r < 0)
 137                                 return r;
 138
 139                         exiting = true;
 140                 }
 141         }
 142
 143         r = sd_event_get_exit_code(e, &code);
 144         if (r < 0)
 145                 return r;
 146
 147         return code;
 148 }
 149
 150 int bus_name_has_owner(sd_bus *c, const char *name, sd_bus_error *error) {
 151         _cleanup_(sd_bus_message_unrefp) sd_bus_message *rep = NULL;
 152         int r, has_owner = 0;
 153
 154         assert(c);
 155         assert(name);
 156
 157         r = sd_bus_call_method(c,
 158                                "org.freedesktop.DBus",
 159                                "/org/freedesktop/dbus",
 160                                "org.freedesktop.DBus",
 161                                "NameHasOwner",
 162                                error,
 163                                &rep,
 164                                "s",
 165                                name);
 166         if (r < 0)
 167                 return r;
 168
 169         r = sd_bus_message_read_basic(rep, 'b', &has_owner);
 170         if (r < 0)
 171                 return sd_bus_error_set_errno(error, r);
 172
 173         return has_owner;
 174 }
 175
 176 bool bus_error_is_unknown_service(const sd_bus_error *error) {
 177         return sd_bus_error_has_names(error,
 178                                       SD_BUS_ERROR_SERVICE_UNKNOWN,
 179                                       SD_BUS_ERROR_NAME_HAS_NO_OWNER,
 180                                       BUS_ERROR_NO_SUCH_UNIT);
 181 }
 182
 183 int bus_check_peercred(sd_bus *c) {
 184         struct ucred ucred;
 185         int fd, r;
 186
 187         assert(c);
 188
 189         fd = sd_bus_get_fd(c);
 190         if (fd < 0)
 191                 return fd;
 192
 193         r = getpeercred(fd, &ucred);
 194         if (r < 0)
 195                 return r;
 196
 197         if (ucred.uid != 0 && ucred.uid != geteuid())
 198                 return -EPERM;
 199
 200         return 1;
 201 }
 202
 203 int bus_connect_system_systemd(sd_bus **ret_bus) {
 204         _cleanup_(sd_bus_close_unrefp) sd_bus *bus = NULL;
 205         int r;
 206
 207         assert(ret_bus);
 208
 209         if (geteuid() != 0)
 210                 return sd_bus_default_system(ret_bus);
 211
 212         /* If we are root then let's talk directly to the system
 213          * instance, instead of going via the bus */
 214
 215         r = sd_bus_new(&bus);
 216         if (r < 0)
 217                 return r;
 218
 219         r = sd_bus_set_address(bus, "unix:path=/run/systemd/private");
 220         if (r < 0)
 221                 return r;
 222
 223         r = sd_bus_start(bus);
 224         if (r < 0)
 225                 return sd_bus_default_system(ret_bus);
 226
 227         r = bus_check_peercred(bus);
 228         if (r < 0)
 229                 return r;
 230
 231         *ret_bus = TAKE_PTR(bus);
 232         return 0;
 233 }
 234
 235 int bus_connect_user_systemd(sd_bus **ret_bus) {
 236         _cleanup_(sd_bus_close_unrefp) sd_bus *bus = NULL;
 237         _cleanup_free_ char *ee = NULL;
 238         const char *e;
 239         int r;
 240
 241         assert(ret_bus);
 242
 243         e = secure_getenv("XDG_RUNTIME_DIR");
 244         if (!e)
 245                 return sd_bus_default_user(ret_bus);
 246
 247         ee = bus_address_escape(e);
 248         if (!ee)
 249                 return -ENOMEM;
 250
 251         r = sd_bus_new(&bus);
 252         if (r < 0)
 253                 return r;
 254
 255         bus->address = strjoin("unix:path=", ee, "/systemd/private");
 256         if (!bus->address)
 257                 return -ENOMEM;
 258
 259         r = sd_bus_start(bus);
 260         if (r < 0)
 261                 return sd_bus_default_user(ret_bus);
 262
 263         r = bus_check_peercred(bus);
 264         if (r < 0)
 265                 return r;
 266
 267         *ret_bus = TAKE_PTR(bus);
 268         return 0;
 269 }
 270
 271 int bus_connect_transport(
 272                 BusTransport transport,
 273                 const char *host,
 274                 RuntimeScope runtime_scope,
 275                 sd_bus **ret) {
 276
 277         _cleanup_(sd_bus_close_unrefp) sd_bus *bus = NULL;
 278         int r;
 279
 280         assert(transport >= 0);
 281         assert(transport < _BUS_TRANSPORT_MAX);
 282         assert(ret);
 283
 284         assert_return((transport == BUS_TRANSPORT_LOCAL) == !host, -EINVAL);
 285         assert_return(transport != BUS_TRANSPORT_REMOTE || runtime_scope == RUNTIME_SCOPE_SYSTEM, -EOPNOTSUPP);
 286
 287         switch (transport) {
 288
 289         case BUS_TRANSPORT_LOCAL:
 290
 291                 switch (runtime_scope) {
 292
 293                 case RUNTIME_SCOPE_USER:
 294                         r = sd_bus_default_user(&bus);
 295                         break;
 296
 297                 case RUNTIME_SCOPE_SYSTEM:
 298                         if (sd_booted() <= 0)
 299                                 /* Print a friendly message when the local system is actually not running systemd as PID 1. */
 300                                 return log_error_errno(SYNTHETIC_ERRNO(EHOSTDOWN),
 301                                                        "System has not been booted with systemd as init system (PID 1). Can't operate.");
 302                         r = sd_bus_default_system(&bus);
 303                         break;
 304
 305                 default:
 306                         assert_not_reached();
 307                 }
 308                 break;
 309
 310         case BUS_TRANSPORT_REMOTE:
 311                 r = sd_bus_open_system_remote(&bus, host);
 312                 break;
 313
 314         case BUS_TRANSPORT_MACHINE:
 315
 316                 switch (runtime_scope) {
 317
 318                 case RUNTIME_SCOPE_USER:
 319                         r = sd_bus_open_user_machine(&bus, host);
 320                         break;
 321
 322                 case RUNTIME_SCOPE_SYSTEM:
 323                         r = sd_bus_open_system_machine(&bus, host);
 324                         break;
 325
 326                 default:
 327                         assert_not_reached();
 328                 }
 329
 330                 break;
 331
 332         default:
 333                 assert_not_reached();
 334         }
 335         if (r < 0)
 336                 return r;
 337
 338         r = sd_bus_set_exit_on_disconnect(bus, true);
 339         if (r < 0)
 340                 return r;
 341
 342         *ret = TAKE_PTR(bus);
 343         return 0;
 344 }
 345
 346 int bus_connect_transport_systemd(BusTransport transport, const char *host, RuntimeScope runtime_scope, sd_bus **bus) {
 347         assert(transport >= 0);
 348         assert(transport < _BUS_TRANSPORT_MAX);
 349         assert(bus);
 350
 351         assert_return((transport == BUS_TRANSPORT_LOCAL) == !host, -EINVAL);
 352         assert_return(transport == BUS_TRANSPORT_LOCAL || runtime_scope == RUNTIME_SCOPE_SYSTEM, -EOPNOTSUPP);
 353
 354         switch (transport) {
 355
 356         case BUS_TRANSPORT_LOCAL:
 357                 switch (runtime_scope) {
 358
 359                 case RUNTIME_SCOPE_USER:
 360                         return bus_connect_user_systemd(bus);
 361
 362                 case RUNTIME_SCOPE_SYSTEM:
 363                         if (sd_booted() <= 0)
 364                                 /* Print a friendly message when the local system is actually not running systemd as PID 1. */
 365                                 return log_error_errno(SYNTHETIC_ERRNO(EHOSTDOWN),
 366                                                        "System has not been booted with systemd as init system (PID 1). Can't operate.");
 367                         return bus_connect_system_systemd(bus);
 368
 369                 default:
 370                         assert_not_reached();
 371                 }
 372
 373                 break;
 374
 375         case BUS_TRANSPORT_REMOTE:
 376                 return sd_bus_open_system_remote(bus, host);
 377
 378         case BUS_TRANSPORT_MACHINE:
 379                 return sd_bus_open_system_machine(bus, host);
 380
 381         default:
 382                 assert_not_reached();
 383         }
 384 }
 385
 386 /**
 387  * bus_path_encode_unique() - encode unique object path
 388  * @b: bus connection or NULL
 389  * @prefix: object path prefix
 390  * @sender_id: unique-name of client, or NULL
 391  * @external_id: external ID to be chosen by client, or NULL
 392  * @ret_path: storage for encoded object path pointer
 393  *
 394  * Whenever we provide a bus API that allows clients to create and manage
 395  * server-side objects, we need to provide a unique name for these objects. If
 396  * we let the server choose the name, we suffer from a race condition: If a
 397  * client creates an object asynchronously, it cannot destroy that object until
 398  * it received the method reply. It cannot know the name of the new object,
 399  * thus, it cannot destroy it. Furthermore, it enforces a round-trip.
 400  *
 401  * Therefore, many APIs allow the client to choose the unique name for newly
 402  * created objects. There're two problems to solve, though:
 403  *    1) Object names are usually defined via dbus object paths, which are
 404  *       usually globally namespaced. Therefore, multiple clients must be able
 405  *       to choose unique object names without interference.
 406  *    2) If multiple libraries share the same bus connection, they must be
 407  *       able to choose unique object names without interference.
 408  * The first problem is solved easily by prefixing a name with the
 409  * unique-bus-name of a connection. The server side must enforce this and
 410  * reject any other name. The second problem is solved by providing unique
 411  * suffixes from within sd-bus.
 412  *
 413  * This helper allows clients to create unique object-paths. It uses the
 414  * template '/prefix/sender_id/external_id' and returns the new path in
 415  * @ret_path (must be freed by the caller).
 416  * If @sender_id is NULL, the unique-name of @b is used. If @external_id is
 417  * NULL, this function allocates a unique suffix via @b (by requesting a new
 418  * cookie). If both @sender_id and @external_id are given, @b can be passed as
 419  * NULL.
 420  *
 421  * Returns: 0 on success, negative error code on failure.
 422  */
 423 int bus_path_encode_unique(sd_bus *b, const char *prefix, const char *sender_id, const char *external_id, char **ret_path) {
 424         _cleanup_free_ char *sender_label = NULL, *external_label = NULL;
 425         char external_buf[DECIMAL_STR_MAX(uint64_t)], *p;
 426         int r;
 427
 428         assert_return(b || (sender_id && external_id), -EINVAL);
 429         assert_return(sd_bus_object_path_is_valid(prefix), -EINVAL);
 430         assert_return(ret_path, -EINVAL);
 431
 432         if (!sender_id) {
 433                 r = sd_bus_get_unique_name(b, &sender_id);
 434                 if (r < 0)
 435                         return r;
 436         }
 437
 438         if (!external_id) {
 439                 xsprintf(external_buf, "%"PRIu64, ++b->cookie);
 440                 external_id = external_buf;
 441         }
 442
 443         sender_label = bus_label_escape(sender_id);
 444         if (!sender_label)
 445                 return -ENOMEM;
 446
 447         external_label = bus_label_escape(external_id);
 448         if (!external_label)
 449                 return -ENOMEM;
 450
 451         p = path_join(prefix, sender_label, external_label);
 452         if (!p)
 453                 return -ENOMEM;
 454
 455         *ret_path = p;
 456         return 0;
 457 }
 458
 459 /**
 460  * bus_path_decode_unique() - decode unique object path
 461  * @path: object path to decode
 462  * @prefix: object path prefix
 463  * @ret_sender: output parameter for sender-id label
 464  * @ret_external: output parameter for external-id label
 465  *
 466  * This does the reverse of bus_path_encode_unique() (see its description for
 467  * details). Both trailing labels, sender-id and external-id, are unescaped and
 468  * returned in the given output parameters (the caller must free them).
 469  *
 470  * Note that this function returns 0 if the path does not match the template
 471  * (see bus_path_encode_unique()), 1 if it matched.
 472  *
 473  * Returns: Negative error code on failure, 0 if the given object path does not
 474  *          match the template (return parameters are set to NULL), 1 if it was
 475  *          parsed successfully (return parameters contain allocated labels).
 476  */
 477 int bus_path_decode_unique(const char *path, const char *prefix, char **ret_sender, char **ret_external) {
 478         const char *p, *q;
 479         char *sender, *external;
 480
 481         assert(sd_bus_object_path_is_valid(path));
 482         assert(sd_bus_object_path_is_valid(prefix));
 483         assert(ret_sender);
 484         assert(ret_external);
 485
 486         p = object_path_startswith(path, prefix);
 487         if (!p) {
 488                 *ret_sender = NULL;
 489                 *ret_external = NULL;
 490                 return 0;
 491         }
 492
 493         q = strchr(p, '/');
 494         if (!q) {
 495                 *ret_sender = NULL;
 496                 *ret_external = NULL;
 497                 return 0;
 498         }
 499
 500         sender = bus_label_unescape_n(p, q - p);
 501         external = bus_label_unescape(q + 1);
 502         if (!sender || !external) {
 503                 free(sender);
 504                 free(external);
 505                 return -ENOMEM;
 506         }
 507
 508         *ret_sender = sender;
 509         *ret_external = external;
 510         return 1;
 511 }
 512
 513 int bus_track_add_name_many(sd_bus_track *t, char **l) {
 514         int r = 0;
 515
 516         assert(t);
 517
 518         /* Continues adding after failure, and returns the first failure. */
 519
 520         STRV_FOREACH(i, l)
 521                 RET_GATHER(r, sd_bus_track_add_name(t, *i));
 522         return r;
 523 }
 524
 525 int bus_open_system_watch_bind_with_description(sd_bus **ret, const char *description) {
 526         _cleanup_(sd_bus_close_unrefp) sd_bus *bus = NULL;
 527         const char *e;
 528         int r;
 529
 530         assert(ret);
 531
 532         /* Match like sd_bus_open_system(), but with the "watch_bind" feature and the Connected() signal
 533          * turned on. */
 534
 535         r = sd_bus_new(&bus);
 536         if (r < 0)
 537                 return r;
 538
 539         if (description) {
 540                 r = sd_bus_set_description(bus, description);
 541                 if (r < 0)
 542                         return r;
 543         }
 544
 545         e = secure_getenv("DBUS_SYSTEM_BUS_ADDRESS");
 546         if (!e)
 547                 e = DEFAULT_SYSTEM_BUS_ADDRESS;
 548
 549         r = sd_bus_set_address(bus, e);
 550         if (r < 0)
 551                 return r;
 552
 553         r = sd_bus_set_bus_client(bus, true);
 554         if (r < 0)
 555                 return r;
 556
 557         r = sd_bus_negotiate_creds(bus, true, SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_EFFECTIVE_CAPS);
 558         if (r < 0)
 559                 return r;
 560
 561         r = sd_bus_set_watch_bind(bus, true);
 562         if (r < 0)
 563                 return r;
 564
 565         r = sd_bus_set_connected_signal(bus, true);
 566         if (r < 0)
 567                 return r;
 568
 569         r = sd_bus_start(bus);
 570         if (r < 0)
 571                 return r;
 572
 573         *ret = TAKE_PTR(bus);
 574
 575         return 0;
 576 }
 577
 578 int bus_reply_pair_array(sd_bus_message *m, char **l) {
 579         _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
 580         int r;
 581
 582         assert(m);
 583
 584         /* Reply to the specified message with a message containing a dictionary put together from the
 585          * specified strv */
 586
 587         r = sd_bus_message_new_method_return(m, &reply);
 588         if (r < 0)
 589                 return r;
 590
 591         r = sd_bus_message_open_container(reply, 'a', "{ss}");
 592         if (r < 0)
 593                 return r;
 594
 595         STRV_FOREACH_PAIR(k, v, l) {
 596                 r = sd_bus_message_append(reply, "{ss}", *k, *v);
 597                 if (r < 0)
 598                         return r;
 599         }
 600
 601         r = sd_bus_message_close_container(reply);
 602         if (r < 0)
 603                 return r;
 604
 605         return sd_bus_send(NULL, reply, NULL);
 606 }
 607
 608 static int method_dump_memory_state_by_fd(sd_bus_message *message, void *userdata, sd_bus_error *ret_error) {
 609         _cleanup_(memstream_done) MemStream m = {};
 610         _cleanup_free_ char *dump = NULL;
 611         _cleanup_close_ int fd = -EBADF;
 612         size_t dump_size;
 613         FILE *f;
 614         int r;
 615
 616         assert(message);
 617
 618         f = memstream_init(&m);
 619         if (!f)
 620                 return -ENOMEM;
 621
 622         r = RET_NERRNO(malloc_info(/* options= */ 0, f));
 623         if (r < 0)
 624                 return r;
 625
 626         r = memstream_finalize(&m, &dump, &dump_size);
 627         if (r < 0)
 628                 return r;
 629
 630         fd = acquire_data_fd(dump, dump_size, 0);
 631         if (fd < 0)
 632                 return fd;
 633
 634         r = sd_bus_reply_method_return(message, "h", fd);
 635         if (r < 0)
 636                 return r;
 637
 638         return 1; /* Stop further processing */
 639 }
 640
 641 /* The default install callback will fail and disconnect the bus if it cannot register the match, but this
 642  * is only a debug method, we definitely don't want to fail in case there's some permission issue. */
 643 static int dummy_install_callback(sd_bus_message *message, void *userdata, sd_bus_error *ret_error) {
 644         return 1;
 645 }
 646
 647 int bus_register_malloc_status(sd_bus *bus, const char *destination) {
 648         const char *match;
 649         int r;
 650
 651         assert(bus);
 652         assert(!isempty(destination));
 653
 654         match = strjoina("type='method_call',"
 655                          "interface='org.freedesktop.MemoryAllocation1',"
 656                          "path='/org/freedesktop/MemoryAllocation1',"
 657                          "destination='", destination, "',",
 658                          "member='GetMallocInfo'");
 659
 660         r = sd_bus_add_match_async(bus, NULL, match, method_dump_memory_state_by_fd, dummy_install_callback, NULL);
 661         if (r < 0)
 662                 return log_debug_errno(r, "Failed to subscribe to GetMallocInfo() calls on MemoryAllocation1 interface: %m");
 663
 664         return 0;
 665 }
 666
 667 static void bus_message_unref_wrapper(void *m) {
 668         sd_bus_message_unref(m);
 669 }
 670
 671 const struct hash_ops bus_message_hash_ops = {
 672         .hash = trivial_hash_func,
 673         .compare = trivial_compare_func,
 674         .free_value = bus_message_unref_wrapper,
 675 };
 676
 677 int bus_message_append_string_set(sd_bus_message *m, Set *set) {
 678         const char *s;
 679         int r;
 680
 681         assert(m);
 682
 683         r = sd_bus_message_open_container(m, 'a', "s");
 684         if (r < 0)
 685                 return r;
 686
 687         SET_FOREACH(s, set) {
 688                 r = sd_bus_message_append(m, "s", s);
 689                 if (r < 0)
 690                         return r;
 691         }
 692
 693         return sd_bus_message_close_container(m);
 694 }
 695
 696 int bus_property_get_string_set(
 697                 sd_bus *bus,
 698                 const char *path,
 699                 const char *interface,
 700                 const char *property,
 701                 sd_bus_message *reply,
 702                 void *userdata,
 703                 sd_bus_error *error) {
 704
 705         Set **s = ASSERT_PTR(userdata);
 706
 707         assert(bus);
 708         assert(property);
 709         assert(reply);
 710
 711         return bus_message_append_string_set(reply, *s);
 712 }
 713
 714 int bus_creds_get_pidref(
 715                 sd_bus_creds *c,
 716                 PidRef *ret) {
 717
 718         int pidfd = -EBADF;
 719         pid_t pid;
 720         int r;
 721
 722         assert(c);
 723         assert(ret);
 724
 725         r = sd_bus_creds_get_pid(c, &pid);
 726         if (r < 0)
 727                 return r;
 728
 729         r = sd_bus_creds_get_pidfd_dup(c, &pidfd);
 730         if (r < 0 && r != -ENODATA)
 731                 return r;
 732
 733         *ret = (PidRef) {
 734                 .pid = pid,
 735                 .fd = pidfd,
 736         };
 737
 738         return 0;
 739 }
 740
 741 int bus_query_sender_pidref(
 742                 sd_bus_message *m,
 743                 PidRef *ret) {
 744
 745         _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
 746         int r;
 747
 748         assert(m);
 749         assert(ret);
 750
 751         r = sd_bus_query_sender_creds(m, SD_BUS_CREDS_PID|SD_BUS_CREDS_PIDFD, &creds);
 752         if (r < 0)
 753                 return r;
 754
 755         return bus_creds_get_pidref(creds, ret);
 756 }