src/libelogind/sd-bus/bus-convenience.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2013 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include "bus-internal.h"
  21 #include "bus-message.h"
  22 #include "bus-signature.h"
  23 #include "bus-type.h"
  24 #include "bus-util.h"
  25 #include "string-util.h"
  26
  27 _public_ int sd_bus_emit_signal(
  28                 sd_bus *bus,
  29                 const char *path,
  30                 const char *interface,
  31                 const char *member,
  32                 const char *types, ...) {
  33
  34         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
  35         int r;
  36
  37         assert_return(bus, -EINVAL);
  38         assert_return(!bus_pid_changed(bus), -ECHILD);
  39
  40         if (!BUS_IS_OPEN(bus->state))
  41                 return -ENOTCONN;
  42
  43         r = sd_bus_message_new_signal(bus, &m, path, interface, member);
  44         if (r < 0)
  45                 return r;
  46
  47         if (!isempty(types)) {
  48                 va_list ap;
  49
  50                 va_start(ap, types);
  51                 r = bus_message_append_ap(m, types, ap);
  52                 va_end(ap);
  53                 if (r < 0)
  54                         return r;
  55         }
  56
  57         return sd_bus_send(bus, m, NULL);
  58 }
  59
  60 #if 0 /// UNNEEDED by elogind
  61 _public_ int sd_bus_call_method_async(
  62                 sd_bus *bus,
  63                 sd_bus_slot **slot,
  64                 const char *destination,
  65                 const char *path,
  66                 const char *interface,
  67                 const char *member,
  68                 sd_bus_message_handler_t callback,
  69                 void *userdata,
  70                 const char *types, ...) {
  71
  72         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
  73         int r;
  74
  75         assert_return(bus, -EINVAL);
  76         assert_return(!bus_pid_changed(bus), -ECHILD);
  77
  78         if (!BUS_IS_OPEN(bus->state))
  79                 return -ENOTCONN;
  80
  81         r = sd_bus_message_new_method_call(bus, &m, destination, path, interface, member);
  82         if (r < 0)
  83                 return r;
  84
  85         if (!isempty(types)) {
  86                 va_list ap;
  87
  88                 va_start(ap, types);
  89                 r = bus_message_append_ap(m, types, ap);
  90                 va_end(ap);
  91                 if (r < 0)
  92                         return r;
  93         }
  94
  95         return sd_bus_call_async(bus, slot, m, callback, userdata, 0);
  96 }
  97 #endif // 0
  98
  99 _public_ int sd_bus_call_method(
 100                 sd_bus *bus,
 101                 const char *destination,
 102                 const char *path,
 103                 const char *interface,
 104                 const char *member,
 105                 sd_bus_error *error,
 106                 sd_bus_message **reply,
 107                 const char *types, ...) {
 108
 109         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
 110         int r;
 111
 112         bus_assert_return(bus, -EINVAL, error);
 113         bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
 114
 115         if (!BUS_IS_OPEN(bus->state)) {
 116                 r = -ENOTCONN;
 117                 goto fail;
 118         }
 119
 120         r = sd_bus_message_new_method_call(bus, &m, destination, path, interface, member);
 121         if (r < 0)
 122                 goto fail;
 123
 124         if (!isempty(types)) {
 125                 va_list ap;
 126
 127                 va_start(ap, types);
 128                 r = bus_message_append_ap(m, types, ap);
 129                 va_end(ap);
 130                 if (r < 0)
 131                         goto fail;
 132         }
 133
 134         return sd_bus_call(bus, m, 0, error, reply);
 135
 136 fail:
 137         return sd_bus_error_set_errno(error, r);
 138 }
 139
 140 _public_ int sd_bus_reply_method_return(
 141                 sd_bus_message *call,
 142                 const char *types, ...) {
 143
 144         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
 145         int r;
 146
 147         assert_return(call, -EINVAL);
 148         assert_return(call->sealed, -EPERM);
 149         assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
 150         assert_return(call->bus, -EINVAL);
 151         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 152
 153         if (!BUS_IS_OPEN(call->bus->state))
 154                 return -ENOTCONN;
 155
 156         if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
 157                 return 0;
 158
 159         r = sd_bus_message_new_method_return(call, &m);
 160         if (r < 0)
 161                 return r;
 162
 163         if (!isempty(types)) {
 164                 va_list ap;
 165
 166                 va_start(ap, types);
 167                 r = bus_message_append_ap(m, types, ap);
 168                 va_end(ap);
 169                 if (r < 0)
 170                         return r;
 171         }
 172
 173         return sd_bus_send(call->bus, m, NULL);
 174 }
 175
 176 _public_ int sd_bus_reply_method_error(
 177                 sd_bus_message *call,
 178                 const sd_bus_error *e) {
 179
 180         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
 181         int r;
 182
 183         assert_return(call, -EINVAL);
 184         assert_return(call->sealed, -EPERM);
 185         assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
 186         assert_return(sd_bus_error_is_set(e), -EINVAL);
 187         assert_return(call->bus, -EINVAL);
 188         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 189
 190         if (!BUS_IS_OPEN(call->bus->state))
 191                 return -ENOTCONN;
 192
 193         if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
 194                 return 0;
 195
 196         r = sd_bus_message_new_method_error(call, &m, e);
 197         if (r < 0)
 198                 return r;
 199
 200         return sd_bus_send(call->bus, m, NULL);
 201 }
 202
 203 _public_ int sd_bus_reply_method_errorf(
 204                 sd_bus_message *call,
 205                 const char *name,
 206                 const char *format,
 207                 ...) {
 208
 209         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 210         va_list ap;
 211
 212         assert_return(call, -EINVAL);
 213         assert_return(call->sealed, -EPERM);
 214         assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
 215         assert_return(call->bus, -EINVAL);
 216         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 217
 218         if (!BUS_IS_OPEN(call->bus->state))
 219                 return -ENOTCONN;
 220
 221         if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
 222                 return 0;
 223
 224         va_start(ap, format);
 225         bus_error_setfv(&error, name, format, ap);
 226         va_end(ap);
 227
 228         return sd_bus_reply_method_error(call, &error);
 229 }
 230
 231 _public_ int sd_bus_reply_method_errno(
 232                 sd_bus_message *call,
 233                 int error,
 234                 const sd_bus_error *p) {
 235
 236         _cleanup_(sd_bus_error_free) sd_bus_error berror = SD_BUS_ERROR_NULL;
 237
 238         assert_return(call, -EINVAL);
 239         assert_return(call->sealed, -EPERM);
 240         assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
 241         assert_return(call->bus, -EINVAL);
 242         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 243
 244         if (!BUS_IS_OPEN(call->bus->state))
 245                 return -ENOTCONN;
 246
 247         if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
 248                 return 0;
 249
 250         if (sd_bus_error_is_set(p))
 251                 return sd_bus_reply_method_error(call, p);
 252
 253         sd_bus_error_set_errno(&berror, error);
 254
 255         return sd_bus_reply_method_error(call, &berror);
 256 }
 257
 258 #if 0 /// UNNEEDED by elogind
 259 _public_ int sd_bus_reply_method_errnof(
 260                 sd_bus_message *call,
 261                 int error,
 262                 const char *format,
 263                 ...) {
 264
 265         _cleanup_(sd_bus_error_free) sd_bus_error berror = SD_BUS_ERROR_NULL;
 266         va_list ap;
 267
 268         assert_return(call, -EINVAL);
 269         assert_return(call->sealed, -EPERM);
 270         assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
 271         assert_return(call->bus, -EINVAL);
 272         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 273
 274         if (!BUS_IS_OPEN(call->bus->state))
 275                 return -ENOTCONN;
 276
 277         if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
 278                 return 0;
 279
 280         va_start(ap, format);
 281         sd_bus_error_set_errnofv(&berror, error, format, ap);
 282         va_end(ap);
 283
 284         return sd_bus_reply_method_error(call, &berror);
 285 }
 286 #endif // 0
 287
 288 _public_ int sd_bus_get_property(
 289                 sd_bus *bus,
 290                 const char *destination,
 291                 const char *path,
 292                 const char *interface,
 293                 const char *member,
 294                 sd_bus_error *error,
 295                 sd_bus_message **reply,
 296                 const char *type) {
 297
 298         sd_bus_message *rep = NULL;
 299         int r;
 300
 301         bus_assert_return(bus, -EINVAL, error);
 302         bus_assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL, error);
 303         bus_assert_return(member_name_is_valid(member), -EINVAL, error);
 304         bus_assert_return(reply, -EINVAL, error);
 305         bus_assert_return(signature_is_single(type, false), -EINVAL, error);
 306         bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
 307
 308         if (!BUS_IS_OPEN(bus->state)) {
 309                 r = -ENOTCONN;
 310                 goto fail;
 311         }
 312
 313         r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &rep, "ss", strempty(interface), member);
 314         if (r < 0)
 315                 return r;
 316
 317         r = sd_bus_message_enter_container(rep, 'v', type);
 318         if (r < 0) {
 319                 sd_bus_message_unref(rep);
 320                 goto fail;
 321         }
 322
 323         *reply = rep;
 324         return 0;
 325
 326 fail:
 327         return sd_bus_error_set_errno(error, r);
 328 }
 329
 330 #if 0 /// UNNEEDED by elogind
 331 _public_ int sd_bus_get_property_trivial(
 332                 sd_bus *bus,
 333                 const char *destination,
 334                 const char *path,
 335                 const char *interface,
 336                 const char *member,
 337                 sd_bus_error *error,
 338                 char type, void *ptr) {
 339
 340         _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
 341         int r;
 342
 343         bus_assert_return(bus, -EINVAL, error);
 344         bus_assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL, error);
 345         bus_assert_return(member_name_is_valid(member), -EINVAL, error);
 346         bus_assert_return(bus_type_is_trivial(type), -EINVAL, error);
 347         bus_assert_return(ptr, -EINVAL, error);
 348         bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
 349
 350         if (!BUS_IS_OPEN(bus->state)) {
 351                 r = -ENOTCONN;
 352                 goto fail;
 353         }
 354
 355         r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &reply, "ss", strempty(interface), member);
 356         if (r < 0)
 357                 return r;
 358
 359         r = sd_bus_message_enter_container(reply, 'v', CHAR_TO_STR(type));
 360         if (r < 0)
 361                 goto fail;
 362
 363         r = sd_bus_message_read_basic(reply, type, ptr);
 364         if (r < 0)
 365                 goto fail;
 366
 367         return 0;
 368
 369 fail:
 370         return sd_bus_error_set_errno(error, r);
 371 }
 372 #endif // 0
 373
 374 _public_ int sd_bus_get_property_string(
 375                 sd_bus *bus,
 376                 const char *destination,
 377                 const char *path,
 378                 const char *interface,
 379                 const char *member,
 380                 sd_bus_error *error,
 381                 char **ret) {
 382
 383         _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
 384         const char *s;
 385         char *n;
 386         int r;
 387
 388         bus_assert_return(bus, -EINVAL, error);
 389         bus_assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL, error);
 390         bus_assert_return(member_name_is_valid(member), -EINVAL, error);
 391         bus_assert_return(ret, -EINVAL, error);
 392         bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
 393
 394         if (!BUS_IS_OPEN(bus->state)) {
 395                 r = -ENOTCONN;
 396                 goto fail;
 397         }
 398
 399         r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &reply, "ss", strempty(interface), member);
 400         if (r < 0)
 401                 return r;
 402
 403         r = sd_bus_message_enter_container(reply, 'v', "s");
 404         if (r < 0)
 405                 goto fail;
 406
 407         r = sd_bus_message_read_basic(reply, 's', &s);
 408         if (r < 0)
 409                 goto fail;
 410
 411         n = strdup(s);
 412         if (!n) {
 413                 r = -ENOMEM;
 414                 goto fail;
 415         }
 416
 417         *ret = n;
 418         return 0;
 419
 420 fail:
 421         return sd_bus_error_set_errno(error, r);
 422 }
 423
 424 #if 0 /// UNNEEDED by elogind
 425 _public_ int sd_bus_get_property_strv(
 426                 sd_bus *bus,
 427                 const char *destination,
 428                 const char *path,
 429                 const char *interface,
 430                 const char *member,
 431                 sd_bus_error *error,
 432                 char ***ret) {
 433
 434         _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
 435         int r;
 436
 437         bus_assert_return(bus, -EINVAL, error);
 438         bus_assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL, error);
 439         bus_assert_return(member_name_is_valid(member), -EINVAL, error);
 440         bus_assert_return(ret, -EINVAL, error);
 441         bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
 442
 443         if (!BUS_IS_OPEN(bus->state)) {
 444                 r = -ENOTCONN;
 445                 goto fail;
 446         }
 447
 448         r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &reply, "ss", strempty(interface), member);
 449         if (r < 0)
 450                 return r;
 451
 452         r = sd_bus_message_enter_container(reply, 'v', NULL);
 453         if (r < 0)
 454                 goto fail;
 455
 456         r = sd_bus_message_read_strv(reply, ret);
 457         if (r < 0)
 458                 goto fail;
 459
 460         return 0;
 461
 462 fail:
 463         return sd_bus_error_set_errno(error, r);
 464 }
 465
 466 _public_ int sd_bus_set_property(
 467                 sd_bus *bus,
 468                 const char *destination,
 469                 const char *path,
 470                 const char *interface,
 471                 const char *member,
 472                 sd_bus_error *error,
 473                 const char *type, ...) {
 474
 475         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
 476         va_list ap;
 477         int r;
 478
 479         bus_assert_return(bus, -EINVAL, error);
 480         bus_assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL, error);
 481         bus_assert_return(member_name_is_valid(member), -EINVAL, error);
 482         bus_assert_return(signature_is_single(type, false), -EINVAL, error);
 483         bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
 484
 485         if (!BUS_IS_OPEN(bus->state)) {
 486                 r = -ENOTCONN;
 487                 goto fail;
 488         }
 489
 490         r = sd_bus_message_new_method_call(bus, &m, destination, path, "org.freedesktop.DBus.Properties", "Set");
 491         if (r < 0)
 492                 goto fail;
 493
 494         r = sd_bus_message_append(m, "ss", strempty(interface), member);
 495         if (r < 0)
 496                 goto fail;
 497
 498         r = sd_bus_message_open_container(m, 'v', type);
 499         if (r < 0)
 500                 goto fail;
 501
 502         va_start(ap, type);
 503         r = bus_message_append_ap(m, type, ap);
 504         va_end(ap);
 505         if (r < 0)
 506                 goto fail;
 507
 508         r = sd_bus_message_close_container(m);
 509         if (r < 0)
 510                 goto fail;
 511
 512         return sd_bus_call(bus, m, 0, error, NULL);
 513
 514 fail:
 515         return sd_bus_error_set_errno(error, r);
 516 }
 517 #endif // 0
 518
 519 _public_ int sd_bus_query_sender_creds(sd_bus_message *call, uint64_t mask, sd_bus_creds **creds) {
 520         sd_bus_creds *c;
 521
 522         assert_return(call, -EINVAL);
 523         assert_return(call->sealed, -EPERM);
 524         assert_return(call->bus, -EINVAL);
 525         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 526
 527         if (!BUS_IS_OPEN(call->bus->state))
 528                 return -ENOTCONN;
 529
 530         c = sd_bus_message_get_creds(call);
 531
 532         /* All data we need? */
 533         if (c && (mask & ~c->mask) == 0) {
 534                 *creds = sd_bus_creds_ref(c);
 535                 return 0;
 536         }
 537
 538         /* No data passed? Or not enough data passed to retrieve the missing bits? */
 539         if (!c || !(c->mask & SD_BUS_CREDS_PID)) {
 540                 /* We couldn't read anything from the call, let's try
 541                  * to get it from the sender or peer. */
 542
 543                 if (call->sender)
 544                         /* There's a sender, but the creds are
 545                          * missing. This means we are talking via
 546                          * dbus1, or are getting a message that was
 547                          * sent to us via kdbus, but was converted
 548                          * from a dbus1 message by the bus-proxy and
 549                          * thus also lacks the creds. */
 550                         return sd_bus_get_name_creds(call->bus, call->sender, mask, creds);
 551                 else
 552                         /* There's no sender, hence we are on a dbus1
 553                          * direct connection. For direct connections
 554                          * the credentials of the AF_UNIX peer matter,
 555                          * which may be queried via
 556                          * sd_bus_get_owner_creds(). */
 557                         return sd_bus_get_owner_creds(call->bus, mask, creds);
 558         }
 559
 560         return bus_creds_extend_by_pid(c, mask, creds);
 561 }
 562
 563 _public_ int sd_bus_query_sender_privilege(sd_bus_message *call, int capability) {
 564         _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
 565         uid_t our_uid;
 566         bool know_caps = false;
 567         int r;
 568
 569         assert_return(call, -EINVAL);
 570         assert_return(call->sealed, -EPERM);
 571         assert_return(call->bus, -EINVAL);
 572         assert_return(!bus_pid_changed(call->bus), -ECHILD);
 573
 574         if (!BUS_IS_OPEN(call->bus->state))
 575                 return -ENOTCONN;
 576
 577         if (capability >= 0) {
 578
 579                 r = sd_bus_query_sender_creds(call, SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_EFFECTIVE_CAPS, &creds);
 580                 if (r < 0)
 581                         return r;
 582
 583                 /* We cannot use augmented caps for authorization,
 584                  * since then data is acquired raceful from
 585                  * /proc. This can never actually happen, but let's
 586                  * better be safe than sorry, and do an extra check
 587                  * here. */
 588                 assert_return((sd_bus_creds_get_augmented_mask(creds) & SD_BUS_CREDS_EFFECTIVE_CAPS) == 0, -EPERM);
 589
 590                 /* Note that not even on kdbus we might have the caps
 591                  * field, due to faked identities, or namespace
 592                  * translation issues. */
 593                 r = sd_bus_creds_has_effective_cap(creds, capability);
 594                 if (r > 0)
 595                         return 1;
 596                 if (r == 0)
 597                         know_caps = true;
 598         } else {
 599                 r = sd_bus_query_sender_creds(call, SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID, &creds);
 600                 if (r < 0)
 601                         return r;
 602         }
 603
 604         /* Now, check the UID, but only if the capability check wasn't
 605          * sufficient */
 606         our_uid = getuid();
 607         if (our_uid != 0 || !know_caps || capability < 0) {
 608                 uid_t sender_uid;
 609
 610                 /* We cannot use augmented uid/euid for authorization,
 611                  * since then data is acquired raceful from
 612                  * /proc. This can never actually happen, but let's
 613                  * better be safe than sorry, and do an extra check
 614                  * here. */
 615                 assert_return((sd_bus_creds_get_augmented_mask(creds) & (SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID)) == 0, -EPERM);
 616
 617                 /* Try to use the EUID, if we have it. */
 618                 r = sd_bus_creds_get_euid(creds, &sender_uid);
 619                 if (r < 0)
 620                         r = sd_bus_creds_get_uid(creds, &sender_uid);
 621
 622                 if (r >= 0) {
 623                         /* Sender has same UID as us, then let's grant access */
 624                         if (sender_uid == our_uid)
 625                                 return 1;
 626
 627                         /* Sender is root, we are not root. */
 628                         if (our_uid != 0 && sender_uid == 0)
 629                                 return 1;
 630                 }
 631         }
 632
 633         return 0;
 634 }