src/common/trigger.c

   1 /*
   2  * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #include <lttng/trigger/trigger-internal.h>
   9 #include <lttng/condition/condition-internal.h>
  10 #include <lttng/action/action-internal.h>
  11 #include <common/credentials.h>
  12 #include <common/payload.h>
  13 #include <common/payload-view.h>
  14 #include <common/error.h>
  15 #include <common/dynamic-array.h>
  16 #include <common/optional.h>
  17 #include <assert.h>
  18 #include <inttypes.h>
  19
  20 LTTNG_HIDDEN
  21 bool lttng_trigger_validate(struct lttng_trigger *trigger)
  22 {
  23         bool valid;
  24
  25         if (!trigger) {
  26                 valid = false;
  27                 goto end;
  28         }
  29
  30         if (!trigger->creds.uid.is_set) {
  31                 valid = false;
  32                 goto end;
  33         }
  34
  35         valid = lttng_condition_validate(trigger->condition) &&
  36                         lttng_action_validate(trigger->action);
  37 end:
  38         return valid;
  39 }
  40
  41 struct lttng_trigger *lttng_trigger_create(
  42                 struct lttng_condition *condition,
  43                 struct lttng_action *action)
  44 {
  45         struct lttng_trigger *trigger = NULL;
  46
  47         if (!condition || !action) {
  48                 goto end;
  49         }
  50
  51         trigger = zmalloc(sizeof(struct lttng_trigger));
  52         if (!trigger) {
  53                 goto end;
  54         }
  55
  56         urcu_ref_init(&trigger->ref);
  57
  58         lttng_condition_get(condition);
  59         trigger->condition = condition;
  60
  61         lttng_action_get(action);
  62         trigger->action = action;
  63
  64 end:
  65         return trigger;
  66 }
  67
  68 /*
  69  * Note: the lack of reference counting 'get' on the condition object is normal.
  70  * This API was exposed as such in 2.11. The client is not expected to call
  71  * lttng_condition_destroy on the returned object.
  72  */
  73 struct lttng_condition *lttng_trigger_get_condition(
  74                 struct lttng_trigger *trigger)
  75 {
  76         return trigger ? trigger->condition : NULL;
  77 }
  78
  79 LTTNG_HIDDEN
  80 const struct lttng_condition *lttng_trigger_get_const_condition(
  81                 const struct lttng_trigger *trigger)
  82 {
  83         return trigger->condition;
  84 }
  85
  86
  87 /*
  88  * Note: the lack of reference counting 'get' on the action object is normal.
  89  * This API was exposed as such in 2.11. The client is not expected to call
  90  * lttng_action_destroy on the returned object.
  91  */
  92 struct lttng_action *lttng_trigger_get_action(
  93                 struct lttng_trigger *trigger)
  94 {
  95         return trigger ? trigger->action : NULL;
  96 }
  97
  98 LTTNG_HIDDEN
  99 const struct lttng_action *lttng_trigger_get_const_action(
 100                 const struct lttng_trigger *trigger)
 101 {
 102         return trigger->action;
 103 }
 104
 105 static void trigger_destroy_ref(struct urcu_ref *ref)
 106 {
 107         struct lttng_trigger *trigger =
 108                         container_of(ref, struct lttng_trigger, ref);
 109         struct lttng_action *action = lttng_trigger_get_action(trigger);
 110         struct lttng_condition *condition =
 111                         lttng_trigger_get_condition(trigger);
 112
 113         assert(action);
 114         assert(condition);
 115
 116         /* Release ownership. */
 117         lttng_action_put(action);
 118         lttng_condition_put(condition);
 119
 120         free(trigger->name);
 121         free(trigger);
 122 }
 123
 124 void lttng_trigger_destroy(struct lttng_trigger *trigger)
 125 {
 126         lttng_trigger_put(trigger);
 127 }
 128
 129 LTTNG_HIDDEN
 130 ssize_t lttng_trigger_create_from_payload(
 131                 struct lttng_payload_view *src_view,
 132                 struct lttng_trigger **trigger)
 133 {
 134         ssize_t ret, offset = 0, condition_size, action_size, name_size = 0;
 135         struct lttng_condition *condition = NULL;
 136         struct lttng_action *action = NULL;
 137         const struct lttng_trigger_comm *trigger_comm;
 138         const char *name = NULL;
 139         struct lttng_credentials creds = {
 140                 .uid = LTTNG_OPTIONAL_INIT_UNSET,
 141                 .gid = LTTNG_OPTIONAL_INIT_UNSET,
 142         };
 143
 144         if (!src_view || !trigger) {
 145                 ret = -1;
 146                 goto end;
 147         }
 148
 149         /* lttng_trigger_comm header */
 150         trigger_comm = (typeof(trigger_comm)) src_view->buffer.data;
 151
 152         /* Set the trigger's creds. */
 153         if (trigger_comm->uid > (uint64_t) ((uid_t) -1)) {
 154                 /* UID out of range for this platform. */
 155                 ret = -1;
 156                 goto end;
 157         }
 158
 159         LTTNG_OPTIONAL_SET(&creds.uid, trigger_comm->uid);
 160
 161         offset += sizeof(*trigger_comm);
 162
 163         if (trigger_comm->name_length != 0) {
 164                 /* Name. */
 165                 const struct lttng_payload_view name_view =
 166                                 lttng_payload_view_from_view(
 167                                                 src_view, offset, trigger_comm->name_length);
 168
 169                 name = name_view.buffer.data;
 170                 if (!lttng_buffer_view_contains_string(&name_view.buffer, name,
 171                                     trigger_comm->name_length)) {
 172                         ret = -1;
 173                         goto end;
 174                 }
 175
 176                 offset += trigger_comm->name_length;
 177                 name_size = trigger_comm->name_length;
 178         }
 179
 180         {
 181                 /* struct lttng_condition */
 182                 struct lttng_payload_view condition_view =
 183                                 lttng_payload_view_from_view(
 184                                                 src_view, offset, -1);
 185
 186                 condition_size = lttng_condition_create_from_payload(&condition_view,
 187                                 &condition);
 188         }
 189
 190         if (condition_size < 0) {
 191                 ret = condition_size;
 192                 goto end;
 193         }
 194
 195         offset += condition_size;
 196         {
 197                 /* struct lttng_action */
 198                 struct lttng_payload_view action_view =
 199                                 lttng_payload_view_from_view(
 200                                         src_view, offset, -1);
 201
 202                 action_size = lttng_action_create_from_payload(&action_view, &action);
 203         }
 204
 205         if (action_size < 0) {
 206                 ret = action_size;
 207                 goto end;
 208         }
 209         offset += action_size;
 210
 211         /* Unexpected size of inner-elements; the buffer is corrupted. */
 212         if ((ssize_t) trigger_comm->length != condition_size + action_size + name_size) {
 213                 ret = -1;
 214                 goto error;
 215         }
 216
 217         *trigger = lttng_trigger_create(condition, action);
 218         if (!*trigger) {
 219                 ret = -1;
 220                 goto error;
 221         }
 222
 223         lttng_trigger_set_credentials(*trigger, &creds);
 224
 225         /*
 226          * The trigger object owns references to the action and condition
 227          * objects.
 228          */
 229         lttng_condition_put(condition);
 230         condition = NULL;
 231
 232         lttng_action_put(action);
 233         action = NULL;
 234
 235         if (name) {
 236                 const enum lttng_trigger_status status =
 237                                 lttng_trigger_set_name(*trigger, name);
 238
 239                 if (status != LTTNG_TRIGGER_STATUS_OK) {
 240                         ret = -1;
 241                         goto end;
 242                 }
 243         }
 244
 245         ret = offset;
 246
 247 error:
 248         lttng_condition_destroy(condition);
 249         lttng_action_destroy(action);
 250 end:
 251         return ret;
 252 }
 253
 254 /*
 255  * Both elements are stored contiguously, see their "*_comm" structure
 256  * for the detailed format.
 257  */
 258 LTTNG_HIDDEN
 259 int lttng_trigger_serialize(const struct lttng_trigger *trigger,
 260                 struct lttng_payload *payload)
 261 {
 262         int ret;
 263         size_t header_offset, size_before_payload, size_name;
 264         struct lttng_trigger_comm trigger_comm = {};
 265         struct lttng_trigger_comm *header;
 266         const struct lttng_credentials *creds = NULL;
 267
 268         creds = lttng_trigger_get_credentials(trigger);
 269         assert(creds);
 270
 271         trigger_comm.uid = LTTNG_OPTIONAL_GET(creds->uid);
 272
 273         if (trigger->name != NULL) {
 274                 size_name = strlen(trigger->name) + 1;
 275         } else {
 276                 size_name = 0;
 277         }
 278
 279         trigger_comm.name_length = size_name;
 280
 281         header_offset = payload->buffer.size;
 282         ret = lttng_dynamic_buffer_append(&payload->buffer, &trigger_comm,
 283                         sizeof(trigger_comm));
 284         if (ret) {
 285                 goto end;
 286         }
 287
 288         size_before_payload = payload->buffer.size;
 289
 290         /* Trigger name. */
 291         ret = lttng_dynamic_buffer_append(
 292                         &payload->buffer, trigger->name, size_name);
 293         if (ret) {
 294                 goto end;
 295         }
 296
 297         ret = lttng_condition_serialize(trigger->condition, payload);
 298         if (ret) {
 299                 goto end;
 300         }
 301
 302         ret = lttng_action_serialize(trigger->action, payload);
 303         if (ret) {
 304                 goto end;
 305         }
 306
 307         /* Update payload size. */
 308         header = (typeof(header)) (payload->buffer.data + header_offset);
 309         header->length = payload->buffer.size - size_before_payload;
 310 end:
 311         return ret;
 312 }
 313
 314 LTTNG_HIDDEN
 315 bool lttng_trigger_is_equal(
 316                 const struct lttng_trigger *a, const struct lttng_trigger *b)
 317 {
 318         /*
 319          * Name is not taken into account since it is cosmetic only.
 320          */
 321         if (!lttng_condition_is_equal(a->condition, b->condition)) {
 322                 return false;
 323         }
 324
 325         if (!lttng_action_is_equal(a->action, b->action)) {
 326                 return false;
 327         }
 328
 329         if (!lttng_credentials_is_equal(lttng_trigger_get_credentials(a),
 330                         lttng_trigger_get_credentials(b))) {
 331                 return false;
 332         }
 333
 334         return true;
 335 }
 336
 337 enum lttng_trigger_status lttng_trigger_set_name(struct lttng_trigger *trigger,
 338                 const char* name)
 339 {
 340         char *name_copy = NULL;
 341         enum lttng_trigger_status status = LTTNG_TRIGGER_STATUS_OK;
 342
 343         if (!trigger || !name ||
 344                         strlen(name) == 0) {
 345                 status = LTTNG_TRIGGER_STATUS_INVALID;
 346                 goto end;
 347         }
 348
 349         name_copy = strdup(name);
 350         if (!name_copy) {
 351                 status = LTTNG_TRIGGER_STATUS_ERROR;
 352                 goto end;
 353         }
 354
 355         free(trigger->name);
 356
 357         trigger->name = name_copy;
 358         name_copy = NULL;
 359 end:
 360         return status;
 361 }
 362
 363 enum lttng_trigger_status lttng_trigger_get_name(
 364                 const struct lttng_trigger *trigger, const char **name)
 365 {
 366         enum lttng_trigger_status status = LTTNG_TRIGGER_STATUS_OK;
 367
 368         if (!trigger || !name) {
 369                 status = LTTNG_TRIGGER_STATUS_INVALID;
 370                 goto end;
 371         }
 372
 373         if (!trigger->name) {
 374                 status = LTTNG_TRIGGER_STATUS_UNSET;
 375         }
 376
 377         *name = trigger->name;
 378 end:
 379         return status;
 380 }
 381
 382 LTTNG_HIDDEN
 383 int lttng_trigger_assign_name(struct lttng_trigger *dst,
 384                 const struct lttng_trigger *src)
 385 {
 386         int ret = 0;
 387         enum lttng_trigger_status status;
 388
 389         status = lttng_trigger_set_name(dst, src->name);
 390         if (status != LTTNG_TRIGGER_STATUS_OK) {
 391                 ret = -1;
 392                 ERR("Failed to set name for trigger");
 393                 goto end;
 394         }
 395 end:
 396         return ret;
 397 }
 398
 399 LTTNG_HIDDEN
 400 void lttng_trigger_set_tracer_token(struct lttng_trigger *trigger,
 401                 uint64_t token)
 402 {
 403         assert(trigger);
 404         LTTNG_OPTIONAL_SET(&trigger->tracer_token, token);
 405 }
 406
 407 LTTNG_HIDDEN
 408 uint64_t lttng_trigger_get_tracer_token(const struct lttng_trigger *trigger)
 409 {
 410         assert(trigger);
 411
 412         return LTTNG_OPTIONAL_GET(trigger->tracer_token);
 413 }
 414
 415 LTTNG_HIDDEN
 416 int lttng_trigger_generate_name(struct lttng_trigger *trigger,
 417                 uint64_t unique_id)
 418 {
 419         int ret = 0;
 420         char *generated_name = NULL;
 421
 422         ret = asprintf(&generated_name, "T%" PRIu64 "", unique_id);
 423         if (ret < 0) {
 424                 ERR("Failed to generate trigger name");
 425                 ret = -1;
 426                 goto end;
 427         }
 428
 429         ret = 0;
 430         free(trigger->name);
 431         trigger->name = generated_name;
 432 end:
 433         return ret;
 434 }
 435
 436 LTTNG_HIDDEN
 437 void lttng_trigger_get(struct lttng_trigger *trigger)
 438 {
 439         urcu_ref_get(&trigger->ref);
 440 }
 441
 442 LTTNG_HIDDEN
 443 void lttng_trigger_put(struct lttng_trigger *trigger)
 444 {
 445         if (!trigger) {
 446                 return;
 447         }
 448
 449         urcu_ref_put(&trigger->ref , trigger_destroy_ref);
 450 }
 451
 452 static void delete_trigger_array_element(void *ptr)
 453 {
 454         struct lttng_trigger *trigger = ptr;
 455
 456         lttng_trigger_put(trigger);
 457 }
 458
 459 LTTNG_HIDDEN
 460 struct lttng_triggers *lttng_triggers_create(void)
 461 {
 462         struct lttng_triggers *triggers = NULL;
 463
 464         triggers = zmalloc(sizeof(*triggers));
 465         if (!triggers) {
 466                 goto end;
 467         }
 468
 469         lttng_dynamic_pointer_array_init(&triggers->array, delete_trigger_array_element);
 470
 471 end:
 472         return triggers;
 473 }
 474
 475 LTTNG_HIDDEN
 476 struct lttng_trigger *lttng_triggers_borrow_mutable_at_index(
 477                 const struct lttng_triggers *triggers, unsigned int index)
 478 {
 479         struct lttng_trigger *trigger = NULL;
 480
 481         assert(triggers);
 482         if (index >= lttng_dynamic_pointer_array_get_count(&triggers->array)) {
 483                 goto end;
 484         }
 485
 486         trigger = (struct lttng_trigger *)
 487                         lttng_dynamic_pointer_array_get_pointer(
 488                                         &triggers->array, index);
 489 end:
 490         return trigger;
 491 }
 492
 493 LTTNG_HIDDEN
 494 int lttng_triggers_add(
 495                 struct lttng_triggers *triggers, struct lttng_trigger *trigger)
 496 {
 497         int ret;
 498
 499         assert(triggers);
 500         assert(trigger);
 501
 502         lttng_trigger_get(trigger);
 503
 504         ret = lttng_dynamic_pointer_array_add_pointer(&triggers->array, trigger);
 505         if (ret) {
 506                 lttng_trigger_put(trigger);
 507         }
 508
 509         return ret;
 510 }
 511
 512 const struct lttng_trigger *lttng_triggers_get_at_index(
 513                 const struct lttng_triggers *triggers, unsigned int index)
 514 {
 515         return lttng_triggers_borrow_mutable_at_index(triggers, index);
 516 }
 517
 518 enum lttng_trigger_status lttng_triggers_get_count(const struct lttng_triggers *triggers, unsigned int *count)
 519 {
 520         enum lttng_trigger_status status = LTTNG_TRIGGER_STATUS_OK;
 521
 522         if (!triggers || !count) {
 523                 status = LTTNG_TRIGGER_STATUS_INVALID;
 524                 goto end;
 525         }
 526
 527         *count = lttng_dynamic_pointer_array_get_count(&triggers->array);
 528 end:
 529         return status;
 530 }
 531
 532 void lttng_triggers_destroy(struct lttng_triggers *triggers)
 533 {
 534         if (!triggers) {
 535                 return;
 536         }
 537
 538         lttng_dynamic_pointer_array_reset(&triggers->array);
 539         free(triggers);
 540 }
 541
 542 int lttng_triggers_serialize(const struct lttng_triggers *triggers,
 543                 struct lttng_payload *payload)
 544 {
 545         int ret;
 546         unsigned int i, count;
 547         size_t size_before_payload;
 548         struct lttng_triggers_comm triggers_comm = {};
 549         struct lttng_triggers_comm *header;
 550         enum lttng_trigger_status status;
 551         const size_t header_offset = payload->buffer.size;
 552
 553         status = lttng_triggers_get_count(triggers, &count);
 554         if (status != LTTNG_TRIGGER_STATUS_OK) {
 555                 ret = LTTNG_ERR_INVALID;
 556                 goto end;
 557         }
 558
 559         triggers_comm.count = count;
 560
 561         /* Placeholder header; updated at the end. */
 562         ret = lttng_dynamic_buffer_append(&payload->buffer, &triggers_comm,
 563                         sizeof(triggers_comm));
 564         if (ret) {
 565                 goto end;
 566         }
 567
 568         size_before_payload = payload->buffer.size;
 569
 570         for (i = 0; i < count; i++) {
 571                 const struct lttng_trigger *trigger =
 572                                 lttng_triggers_get_at_index(triggers, i);
 573
 574                 assert(trigger);
 575
 576                 ret = lttng_trigger_serialize(trigger, payload);
 577                 if (ret) {
 578                         goto end;
 579                 }
 580         }
 581
 582         /* Update payload size. */
 583         header = (struct lttng_triggers_comm *) ((char *) payload->buffer.data + header_offset);
 584         header->length = payload->buffer.size - size_before_payload;
 585 end:
 586         return ret;
 587 }
 588
 589 LTTNG_HIDDEN
 590 ssize_t lttng_triggers_create_from_payload(
 591                 struct lttng_payload_view *src_view,
 592                 struct lttng_triggers **triggers)
 593 {
 594         ssize_t ret, offset = 0, triggers_size = 0;
 595         unsigned int i;
 596         const struct lttng_triggers_comm *triggers_comm;
 597         struct lttng_triggers *local_triggers = NULL;
 598
 599         if (!src_view || !triggers) {
 600                 ret = -1;
 601                 goto error;
 602         }
 603
 604         /* lttng_trigger_comms header */
 605         triggers_comm = (const struct lttng_triggers_comm *) src_view->buffer.data;
 606         offset += sizeof(*triggers_comm);
 607
 608         local_triggers = lttng_triggers_create();
 609         if (!local_triggers) {
 610                 ret = -1;
 611                 goto error;
 612         }
 613
 614         for (i = 0; i < triggers_comm->count; i++) {
 615                 struct lttng_trigger *trigger = NULL;
 616                 struct lttng_payload_view trigger_view =
 617                                 lttng_payload_view_from_view(src_view, offset, -1);
 618                 ssize_t trigger_size;
 619
 620                 trigger_size = lttng_trigger_create_from_payload(
 621                                 &trigger_view, &trigger);
 622                 if (trigger_size < 0) {
 623                         ret = trigger_size;
 624                         goto error;
 625                 }
 626
 627                 /* Transfer ownership of the trigger to the collection. */
 628                 ret = lttng_triggers_add(local_triggers, trigger);
 629                 lttng_trigger_put(trigger);
 630                 if (ret < 0) {
 631                         ret = -1;
 632                         goto error;
 633                 }
 634
 635                 offset += trigger_size;
 636                 triggers_size += trigger_size;
 637         }
 638
 639         /* Unexpected size of inner-elements; the buffer is corrupted. */
 640         if ((ssize_t) triggers_comm->length != triggers_size) {
 641                 ret = -1;
 642                 goto error;
 643         }
 644
 645         /* Pass ownership to caller. */
 646         *triggers = local_triggers;
 647         local_triggers = NULL;
 648
 649         ret = offset;
 650 error:
 651
 652         lttng_triggers_destroy(local_triggers);
 653         return ret;
 654 }
 655
 656 LTTNG_HIDDEN
 657 const struct lttng_credentials *lttng_trigger_get_credentials(
 658                 const struct lttng_trigger *trigger)
 659 {
 660         return &trigger->creds;
 661 }
 662
 663 LTTNG_HIDDEN
 664 void lttng_trigger_set_credentials(struct lttng_trigger *trigger,
 665                 const struct lttng_credentials *creds)
 666 {
 667         assert(creds);
 668         trigger->creds = *creds;
 669 }
 670
 671 enum lttng_trigger_status lttng_trigger_set_owner_uid(
 672                 struct lttng_trigger *trigger, uid_t uid)
 673 {
 674         enum lttng_trigger_status ret = LTTNG_TRIGGER_STATUS_OK;
 675         const struct lttng_credentials creds = {
 676                 .uid = LTTNG_OPTIONAL_INIT_VALUE(uid),
 677                 .gid = LTTNG_OPTIONAL_INIT_UNSET,
 678         };
 679
 680         if (!trigger) {
 681                 ret = LTTNG_TRIGGER_STATUS_INVALID;
 682                 goto end;
 683         }
 684
 685         /* Client-side validation only to report a clearer error. */
 686         if (geteuid() != 0) {
 687                 ret = LTTNG_TRIGGER_STATUS_PERMISSION_DENIED;
 688                 goto end;
 689         }
 690
 691         lttng_trigger_set_credentials(trigger, &creds);
 692
 693 end:
 694         return ret;
 695 }
 696
 697 enum lttng_trigger_status lttng_trigger_get_owner_uid(
 698                 const struct lttng_trigger *trigger, uid_t *uid)
 699 {
 700         enum lttng_trigger_status ret = LTTNG_TRIGGER_STATUS_OK;
 701         const struct lttng_credentials *creds = NULL;
 702
 703         if (!trigger || !uid ) {
 704                 ret = LTTNG_TRIGGER_STATUS_INVALID;
 705                 goto end;
 706         }
 707
 708         if (!trigger->creds.uid.is_set ) {
 709                 ret = LTTNG_TRIGGER_STATUS_UNSET;
 710                 goto end;
 711         }
 712
 713         creds = lttng_trigger_get_credentials(trigger);
 714         *uid = lttng_credentials_get_uid(creds);
 715
 716 end:
 717         return ret;
 718 }