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

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