src/libsystemd-bus/bus-util.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2013 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 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   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <sys/socket.h>
  23
  24 #include "util.h"
  25 #include "strv.h"
  26 #include "macro.h"
  27 #include "def.h"
  28
  29 #include "sd-event.h"
  30 #include "sd-bus.h"
  31 #include "bus-error.h"
  32 #include "bus-message.h"
  33
  34 #include "bus-util.h"
  35
  36 static int quit_callback(sd_bus *bus, sd_bus_message *m, void *userdata) {
  37         sd_event *e = userdata;
  38
  39         assert(bus);
  40         assert(m);
  41         assert(e);
  42
  43         sd_event_request_quit(e);
  44         return 1;
  45 }
  46
  47 int bus_async_unregister_and_quit(sd_event *e, sd_bus *bus, const char *name) {
  48         _cleanup_free_ char *match = NULL;
  49         int r;
  50
  51         assert(e);
  52         assert(bus);
  53         assert(name);
  54
  55         r = asprintf(&match, "type='signal',sender='org.freedesktop.DBus',interface='org.freedesktop.DBus',member='NameLost',arg0='%s'", name);
  56         if (r < 0)
  57                 return r;
  58
  59         r = sd_bus_add_match(bus, match, quit_callback, e);
  60         if (r < 0)
  61                 return r;
  62
  63         r = sd_bus_release_name(bus, name);
  64         if (r < 0)
  65                 return r;
  66
  67         if (r != SD_BUS_NAME_RELEASED)
  68                 return -EIO;
  69
  70         return 0;
  71 }
  72
  73 int bus_event_loop_with_idle(sd_event *e, sd_bus *bus, const char *name, usec_t timeout) {
  74         bool exiting = false;
  75         int r;
  76
  77         assert(e);
  78         assert(bus);
  79         assert(name);
  80
  81         for (;;) {
  82                 r = sd_event_get_state(e);
  83                 if (r < 0)
  84                         return r;
  85
  86                 if (r == SD_EVENT_FINISHED)
  87                         break;
  88
  89                 r = sd_event_run(e, exiting ? (uint64_t) -1 : timeout);
  90                 if (r < 0)
  91                         return r;
  92
  93                 if (r == 0 && !exiting) {
  94                         r = bus_async_unregister_and_quit(e, bus, name);
  95                         if (r < 0)
  96                                 return r;
  97
  98                         exiting = true;
  99                 }
 100         }
 101
 102         return 0;
 103 }
 104
 105 int bus_property_get_tristate(
 106                 sd_bus *bus,
 107                 const char *path,
 108                 const char *interface,
 109                 const char *property,
 110                 sd_bus_message *reply,
 111                 sd_bus_error *error,
 112                 void *userdata) {
 113
 114         int *tristate = userdata;
 115         int r;
 116
 117         r = sd_bus_message_append(reply, "b", *tristate > 0);
 118         if (r < 0)
 119                 return r;
 120
 121         return 1;
 122 }
 123
 124 int bus_verify_polkit(
 125                 sd_bus *bus,
 126                 sd_bus_message *m,
 127                 const char *action,
 128                 bool interactive,
 129                 bool *_challenge,
 130                 sd_bus_error *e) {
 131
 132         const char *sender;
 133         uid_t uid;
 134         int r;
 135
 136         assert(bus);
 137         assert(m);
 138         assert(action);
 139
 140         sender = sd_bus_message_get_sender(m);
 141         if (!sender)
 142                 return -EBADMSG;
 143
 144         r = sd_bus_get_owner_uid(bus, sender, &uid);
 145         if (r < 0)
 146                 return r;
 147
 148         if (uid == 0)
 149                 return 1;
 150
 151 #ifdef ENABLE_POLKIT
 152         else {
 153                 _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
 154                 unsigned authorized = false, challenge = false;
 155
 156                 r = sd_bus_call_method(
 157                                 bus,
 158                                 "org.freedesktop.PolicyKit1",
 159                                 "/org/freedesktop/PolicyKit1/Authority",
 160                                 "org.freedesktop.PolicyKit1.Authority",
 161                                 "CheckAuthorization",
 162                                 e,
 163                                 &reply,
 164                                 "(sa{sv})sa{ss}us",
 165                                 "system-bus-name", 1, "name", "s", sender,
 166                                 action,
 167                                 0,
 168                                 interactive ? 1 : 0,
 169                                 "");
 170
 171                 if (r < 0) {
 172                         /* Treat no PK available as access denied */
 173                         if (sd_bus_error_has_name(e, SD_BUS_ERROR_SERVICE_UNKNOWN)) {
 174                                 sd_bus_error_free(e);
 175                                 return -EACCES;
 176                         }
 177
 178                         return r;
 179                 }
 180
 181                 r = sd_bus_message_read(reply, "(bb)", &authorized, &challenge);
 182                 if (r < 0)
 183                         return r;
 184
 185                 if (authorized)
 186                         return 1;
 187
 188                 if (_challenge) {
 189                         *_challenge = challenge;
 190                         return 0;
 191                 }
 192         }
 193 #endif
 194
 195         return -EACCES;
 196 }
 197
 198 #ifdef ENABLE_POLKIT
 199
 200 typedef struct AsyncPolkitQuery {
 201         sd_bus_message *request, *reply;
 202         sd_bus_message_handler_t callback;
 203         void *userdata;
 204         uint64_t serial;
 205 } AsyncPolkitQuery;
 206
 207 static int async_polkit_callback(sd_bus *bus, sd_bus_message *reply, void *userdata) {
 208         AsyncPolkitQuery *q = userdata;
 209         _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
 210         int r;
 211
 212         assert(bus);
 213         assert(reply);
 214         assert(q);
 215
 216         q->reply = sd_bus_message_ref(reply);
 217         q->serial = 0;
 218
 219         m = sd_bus_message_ref(q->request);
 220
 221         r = sd_bus_message_rewind(m, true);
 222         if (r < 0)
 223                 return r;
 224
 225         r = q->callback(bus, m, q->userdata);
 226         if (r < 0)
 227                 return r;
 228
 229         return 1;
 230 }
 231
 232 static void async_polkit_query_free(sd_bus *b, AsyncPolkitQuery *q) {
 233
 234         if (!q)
 235                 return;
 236
 237         if (q->serial >  0 && b)
 238                 sd_bus_send_with_reply_cancel(b, q->serial);
 239
 240         sd_bus_message_unref(q->request);
 241         sd_bus_message_unref(q->reply);
 242         free(q);
 243 }
 244
 245 #endif
 246
 247 int bus_verify_polkit_async(
 248                 sd_bus *bus,
 249                 Hashmap **registry,
 250                 sd_bus_message *m,
 251                 const char *action,
 252                 bool interactive,
 253                 sd_bus_error *error,
 254                 sd_bus_message_handler_t callback,
 255                 void *userdata) {
 256
 257 #ifdef ENABLE_POLKIT
 258         _cleanup_bus_message_unref_ sd_bus_message *pk = NULL;
 259         AsyncPolkitQuery *q;
 260 #endif
 261         const char *sender;
 262         uid_t uid;
 263         int r;
 264
 265         assert(bus);
 266         assert(registry);
 267         assert(m);
 268         assert(action);
 269
 270 #ifdef ENABLE_POLKIT
 271         q = hashmap_remove(*registry, m);
 272         if (q) {
 273                 unsigned authorized, challenge;
 274
 275                 /* This is the second invocation of this function, and
 276                  * there's already a response from polkit, let's
 277                  * process it */
 278                 assert(q->reply);
 279
 280                 if (sd_bus_message_is_method_error(q->reply, NULL)) {
 281                         const sd_bus_error *e;
 282
 283                         /* Treat no PK available as access denied */
 284                         if (sd_bus_message_is_method_error(q->reply, SD_BUS_ERROR_SERVICE_UNKNOWN)) {
 285                                 async_polkit_query_free(bus, q);
 286                                 return -EACCES;
 287                         }
 288
 289                         e = sd_bus_message_get_error(q->reply);
 290                         sd_bus_error_copy(error, e);
 291                         r = sd_bus_error_get_errno(e);
 292
 293                         async_polkit_query_free(bus, q);
 294                         return r;
 295                 }
 296
 297                 r = sd_bus_message_enter_container(q->reply, 'r', "bba{ss}");
 298                 if (r >= 0)
 299                         r = sd_bus_message_read(q->reply, "bb", &authorized, &challenge);
 300
 301                 async_polkit_query_free(bus, q);
 302
 303                 if (r < 0)
 304                         return r;
 305
 306                 if (authorized)
 307                         return 1;
 308
 309                 return -EACCES;
 310         }
 311 #endif
 312
 313         sender = sd_bus_message_get_sender(m);
 314         if (!sender)
 315                 return -EBADMSG;
 316
 317         r = sd_bus_get_owner_uid(bus, sender, &uid);
 318         if (r < 0)
 319                 return r;
 320
 321         if (uid == 0)
 322                 return 1;
 323 #ifdef ENABLE_POLKIT
 324
 325         r = hashmap_ensure_allocated(registry, trivial_hash_func, trivial_compare_func);
 326         if (r < 0)
 327                 return r;
 328
 329         r = sd_bus_message_new_method_call(
 330                         bus,
 331                         "org.freedesktop.PolicyKit1",
 332                         "/org/freedesktop/PolicyKit1/Authority",
 333                         "org.freedesktop.PolicyKit1.Authority",
 334                         "CheckAuthorization",
 335                         &pk);
 336         if (r < 0)
 337                 return r;
 338
 339         r = sd_bus_message_append(
 340                         pk,
 341                         "(sa{sv})sa{ss}us",
 342                         "system-bus-name", 1, "name", "s", sender,
 343                         action,
 344                         0,
 345                         interactive ? 1 : 0,
 346                         "");
 347         if (r < 0)
 348                 return r;
 349
 350         q = new0(AsyncPolkitQuery, 1);
 351         if (!q)
 352                 return -ENOMEM;
 353
 354         q->request = sd_bus_message_ref(m);
 355         q->callback = callback;
 356         q->userdata = userdata;
 357
 358         r = hashmap_put(*registry, m, q);
 359         if (r < 0) {
 360                 async_polkit_query_free(bus, q);
 361                 return r;
 362         }
 363
 364         r = sd_bus_send_with_reply(bus, pk, async_polkit_callback, q, 0, &q->serial);
 365         if (r < 0)
 366                 return r;
 367
 368         return 0;
 369 #endif
 370
 371         return -EACCES;
 372 }
 373
 374 void bus_verify_polkit_async_registry_free(sd_bus *bus, Hashmap *registry) {
 375 #ifdef ENABLE_POLKIT
 376         AsyncPolkitQuery *q;
 377
 378         while ((q = hashmap_steal_first(registry)))
 379                 async_polkit_query_free(bus, q);
 380
 381         hashmap_free(registry);
 382 #endif
 383 }
 384
 385 static int bus_check_peercred(sd_bus *c) {
 386         struct ucred ucred;
 387         socklen_t l;
 388         int fd;
 389
 390         assert(c);
 391
 392         fd = sd_bus_get_fd(c);
 393         if (fd < 0)
 394                 return fd;
 395
 396         l = sizeof(struct ucred);
 397         if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &l) < 0)
 398                 return -errno;
 399
 400         if (l != sizeof(struct ucred))
 401                 return -E2BIG;
 402
 403         if (ucred.uid != 0 && ucred.uid != geteuid())
 404                 return -EPERM;
 405
 406         return 1;
 407 }
 408
 409 int bus_open_system_systemd(sd_bus **_bus) {
 410         _cleanup_bus_unref_ sd_bus *bus = NULL;
 411         int r;
 412
 413         assert(_bus);
 414
 415         if (geteuid() != 0)
 416                 return sd_bus_open_system(_bus);
 417
 418         /* If we are root, then let's talk directly to the system
 419          * instance, instead of going via the bus */
 420
 421         r = sd_bus_new(&bus);
 422         if (r < 0)
 423                 return r;
 424
 425         r = sd_bus_set_address(bus, "unix:path=/run/systemd/private");
 426         if (r < 0)
 427                 return r;
 428
 429         r = sd_bus_start(bus);
 430         if (r < 0)
 431                 return r;
 432
 433         r = bus_check_peercred(bus);
 434         if (r < 0)
 435                 return r;
 436
 437         *_bus = bus;
 438         bus = NULL;
 439
 440         return 0;
 441 }
 442
 443 int bus_generic_print_property(const char *name, sd_bus_message *property, bool all) {
 444         char type;
 445         const char *contents;
 446
 447         assert(name);
 448         assert(property);
 449
 450         sd_bus_message_peek_type(property, &type, &contents);
 451
 452         switch (type) {
 453
 454         case SD_BUS_TYPE_STRING: {
 455                 const char *s;
 456                 sd_bus_message_read_basic(property, type, &s);
 457
 458                 if (all || !isempty(s))
 459                         printf("%s=%s\n", name, s);
 460
 461                 return 1;
 462         }
 463
 464         case SD_BUS_TYPE_BOOLEAN: {
 465                 bool b;
 466
 467                 sd_bus_message_read_basic(property, type, &b);
 468                 printf("%s=%s\n", name, yes_no(b));
 469
 470                 return 1;
 471         }
 472
 473         case SD_BUS_TYPE_UINT64: {
 474                 uint64_t u;
 475
 476                 sd_bus_message_read_basic(property, type, &u);
 477
 478                 /* Yes, heuristics! But we can change this check
 479                  * should it turn out to not be sufficient */
 480
 481                 if (endswith(name, "Timestamp")) {
 482                         char timestamp[FORMAT_TIMESTAMP_MAX], *t;
 483
 484                         t = format_timestamp(timestamp, sizeof(timestamp), u);
 485                         if (t || all)
 486                                 printf("%s=%s\n", name, strempty(t));
 487
 488                 } else if (strstr(name, "USec")) {
 489                         char timespan[FORMAT_TIMESPAN_MAX];
 490
 491                         printf("%s=%s\n", name, format_timespan(timespan, sizeof(timespan), u, 0));
 492                 } else
 493                         printf("%s=%llu\n", name, (unsigned long long) u);
 494
 495                 return 1;
 496         }
 497
 498         case SD_BUS_TYPE_UINT32: {
 499                 uint32_t u;
 500
 501                 sd_bus_message_read_basic(property, type, &u);
 502
 503                 if (strstr(name, "UMask") || strstr(name, "Mode"))
 504                         printf("%s=%04o\n", name, u);
 505                 else
 506                         printf("%s=%u\n", name, (unsigned) u);
 507
 508                 return 1;
 509         }
 510
 511         case SD_BUS_TYPE_INT32: {
 512                 int32_t i;
 513
 514                 sd_bus_message_read_basic(property, type, &i);
 515
 516                 printf("%s=%i\n", name, (int) i);
 517                 return 1;
 518         }
 519
 520         case SD_BUS_TYPE_DOUBLE: {
 521                 double d;
 522
 523                 sd_bus_message_read_basic(property, type, &d);
 524
 525                 printf("%s=%g\n", name, d);
 526                 return 1;
 527         }
 528
 529         case SD_BUS_TYPE_ARRAY:
 530
 531                 if (streq(contents, "s")) {
 532                         bool space = false;
 533                         char tp;
 534                         const char *cnt;
 535
 536                         sd_bus_message_enter_container(property, SD_BUS_TYPE_ARRAY, contents);
 537
 538                         sd_bus_message_peek_type(property, &tp, &cnt);
 539                         if (all || cnt) {
 540                                 const char *str;
 541
 542                                 printf("%s=", name);
 543
 544
 545                                 while(sd_bus_message_read_basic(property, SD_BUS_TYPE_STRING, &str) > 0) {
 546                                         printf("%s%s", space ? " " : "", str);
 547
 548                                         space = true;
 549                                 }
 550
 551                                 puts("");
 552                         }
 553
 554                         sd_bus_message_exit_container(property);
 555
 556                         return 1;
 557
 558                 } else if (streq(contents, "y")) {
 559                         const uint8_t *u;
 560                         size_t n;
 561
 562                         sd_bus_message_read_array(property, SD_BUS_TYPE_BYTE, (const void**) &u, &n);
 563                         if (all || n > 0) {
 564                                 unsigned int i;
 565
 566                                 printf("%s=", name);
 567
 568                                 for (i = 0; i < n; i++)
 569                                         printf("%02x", u[i]);
 570
 571                                 puts("");
 572                         }
 573
 574                         return 1;
 575
 576                 } else if (streq(contents, "u")) {
 577                         uint32_t *u;
 578                         size_t n;
 579
 580                         sd_bus_message_read_array(property, SD_BUS_TYPE_UINT32, (const void**) &u, &n);
 581                         if (all || n > 0) {
 582                                 unsigned int i;
 583
 584                                 printf("%s=", name);
 585
 586                                 for (i = 0; i < n; i++)
 587                                         printf("%08x", u[i]);
 588
 589                                 puts("");
 590                         }
 591
 592                         return 1;
 593                 }
 594
 595                 break;
 596         }
 597
 598         return 0;
 599 }
 600
 601 int bus_map_all_properties(sd_bus *bus,
 602                            const char *destination,
 603                            const char *path,
 604                            const struct bus_properties_map *map) {
 605         _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
 606         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 607         int r;
 608
 609         r = sd_bus_call_method( bus,
 610                         destination,
 611                         path,
 612                         "org.freedesktop.DBus.Properties",
 613                         "GetAll",
 614                         &error,
 615                         &m,
 616                         "s", "");
 617         if (r < 0) {
 618                 log_error("Could not get properties: %s", bus_error_message(&error, -r));
 619                 return r;
 620         }
 621
 622         r = sd_bus_message_enter_container(m, SD_BUS_TYPE_ARRAY, "{sv}");
 623         if (r < 0)
 624                 return r;
 625
 626         while ((r = sd_bus_message_enter_container(m, SD_BUS_TYPE_DICT_ENTRY, "sv")) > 0) {
 627                 const char *name;
 628                 char type;
 629                 const char *contents;
 630                 unsigned i;
 631
 632                 r = sd_bus_message_read_basic(m, SD_BUS_TYPE_STRING, &name);
 633                 if (r < 0)
 634                         return r;
 635
 636                 r = sd_bus_message_peek_type(m, NULL, &contents);
 637                 if (r < 0)
 638                         return r;
 639
 640                 r = sd_bus_message_enter_container(m, SD_BUS_TYPE_VARIANT, contents);
 641                 if (r < 0)
 642                         return r;
 643
 644                 r = sd_bus_message_peek_type(m, &type, &contents);
 645                 if (r < 0) {
 646                         log_error("Could not determine type of message: %s", strerror(-r));
 647                         return r;
 648                 }
 649
 650                 switch (type) {
 651                 case SD_BUS_TYPE_STRING: {
 652                         const char *s;
 653
 654                         sd_bus_message_read_basic(m, type, &s);
 655                         if (isempty(s))
 656                                 break;
 657
 658                         for (i = 0; map[i].type; i++) {
 659                                 const char **p;
 660
 661                                 if (!streq(map[i].type, "s"))
 662                                         continue;
 663                                 if (!streq(map[i].name, name))
 664                                         continue;
 665
 666                                 p = map[i].ptr;
 667                                 *p = strdup(s);
 668                                 if (!*p) {
 669                                         r = -ENOMEM;
 670                                         goto fail;
 671                                 }
 672                         }
 673                         break;
 674                 }
 675
 676                 case SD_BUS_TYPE_ARRAY: {
 677                         _cleanup_strv_free_ char **l = NULL;
 678
 679                         if (!streq(contents, "s"))
 680                                 break;
 681
 682                         for (i = 0; map[i].type; i++) {
 683                                 char ***p;
 684
 685                                 if (!streq(map[i].type, "as"))
 686                                         continue;
 687                                 if (!streq(map[i].name, name))
 688                                         continue;
 689
 690                                 r = bus_message_read_strv_extend(m, &l);
 691                                 if (r < 0)
 692                                         break;
 693
 694                                 p = map[i].ptr;
 695                                 strv_free(*p);
 696                                 *p = l;
 697                                 l = NULL;
 698                         }
 699                         break;
 700                 }
 701
 702                 case SD_BUS_TYPE_BOOLEAN: {
 703                         unsigned b;
 704
 705                         sd_bus_message_read_basic(m, type, &b);
 706
 707                         for (i = 0; map[i].type; i++) {
 708                                 bool *p;
 709
 710                                 if (!streq(map[i].type, "b"))
 711                                         continue;
 712                                 if (!streq(map[i].name, name))
 713                                         continue;
 714
 715                                 p = map[i].ptr;
 716                                 *p = b;
 717                         }
 718                         break;
 719                 }
 720
 721                 case SD_BUS_TYPE_UINT64: {
 722                         uint64_t t;
 723
 724                         sd_bus_message_read_basic(m, type, &t);
 725
 726                         for (i = 0; map[i].type; i++) {
 727                                 uint64_t *p;
 728
 729                                 if (!streq(map[i].type, "t"))
 730                                         continue;
 731                                 if (!streq(map[i].name, name))
 732                                         continue;
 733
 734                                 p = map[i].ptr;
 735                                 *p = t;
 736                         }
 737                         break;
 738                 }
 739
 740                 default:
 741                         break;
 742                 }
 743
 744                 r = sd_bus_message_exit_container(m);
 745                 if (r < 0)
 746                         return r;
 747
 748                 r = sd_bus_message_exit_container(m);
 749                 if (r < 0)
 750                         return r;
 751         }
 752
 753 fail:
 754         return r;
 755 }
 756
 757 int bus_open_transport(BusTransport transport, const char *host, bool user, sd_bus **bus) {
 758         int r;
 759
 760         assert(transport >= 0);
 761         assert(transport < _BUS_TRANSPORT_MAX);
 762         assert(bus);
 763
 764         assert_return((transport == BUS_TRANSPORT_LOCAL) == !host, -EINVAL);
 765         assert_return(transport == BUS_TRANSPORT_LOCAL || !user, -ENOTSUP);
 766
 767         switch (transport) {
 768
 769         case BUS_TRANSPORT_LOCAL:
 770                 if (user)
 771                         r = sd_bus_open_user(bus);
 772                 else
 773                         r = sd_bus_open_system(bus);
 774
 775                 break;
 776
 777         case BUS_TRANSPORT_REMOTE:
 778                 r = sd_bus_open_system_remote(host, bus);
 779                 break;
 780
 781         case BUS_TRANSPORT_CONTAINER:
 782                 r = sd_bus_open_system_container(host, bus);
 783                 break;
 784
 785         default:
 786                 assert_not_reached("Hmm, unknown transport type.");
 787         }
 788
 789         return r;
 790 }