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         const struct lttng_payload_view trigger_comm_view =
 144                         lttng_payload_view_from_view(
 145                                         src_view, 0, sizeof(*trigger_comm));
 146
 147         if (!src_view || !trigger) {
 148                 ret = -1;
 149                 goto end;
 150         }
 151
 152         if (!lttng_payload_view_is_valid(&trigger_comm_view)) {
 153                 /* Payload not large enough to contain the header. */
 154                 ret = -1;
 155                 goto end;
 156         }
 157
 158         /* lttng_trigger_comm header */
 159         trigger_comm = (typeof(trigger_comm)) trigger_comm_view.buffer.data;
 160
 161         /* Set the trigger's creds. */
 162         if (trigger_comm->uid > (uint64_t) ((uid_t) -1)) {
 163                 /* UID out of range for this platform. */
 164                 ret = -1;
 165                 goto end;
 166         }
 167
 168         LTTNG_OPTIONAL_SET(&creds.uid, trigger_comm->uid);
 169
 170         offset += sizeof(*trigger_comm);
 171
 172         if (trigger_comm->name_length != 0) {
 173                 /* Name. */
 174                 const struct lttng_payload_view name_view =
 175                                 lttng_payload_view_from_view(
 176                                                 src_view, offset,
 177                                                 trigger_comm->name_length);
 178
 179                 if (!lttng_payload_view_is_valid(&name_view)) {
 180                         ret = -1;
 181                         goto end;
 182                 }
 183
 184                 name = name_view.buffer.data;
 185                 if (!lttng_buffer_view_contains_string(&name_view.buffer, name,
 186                                     trigger_comm->name_length)) {
 187                         ret = -1;
 188                         goto end;
 189                 }
 190
 191                 offset += trigger_comm->name_length;
 192                 name_size = trigger_comm->name_length;
 193         }
 194
 195         {
 196                 /* struct lttng_condition */
 197                 struct lttng_payload_view condition_view =
 198                                 lttng_payload_view_from_view(
 199                                                 src_view, offset, -1);
 200
 201                 condition_size = lttng_condition_create_from_payload(&condition_view,
 202                                 &condition);
 203         }
 204
 205         if (condition_size < 0) {
 206                 ret = condition_size;
 207                 goto end;
 208         }
 209
 210         offset += condition_size;
 211         {
 212                 /* struct lttng_action */
 213                 struct lttng_payload_view action_view =
 214                                 lttng_payload_view_from_view(
 215                                         src_view, offset, -1);
 216
 217                 action_size = lttng_action_create_from_payload(&action_view, &action);
 218         }
 219
 220         if (action_size < 0) {
 221                 ret = action_size;
 222                 goto end;
 223         }
 224         offset += action_size;
 225
 226         /* Unexpected size of inner-elements; the buffer is corrupted. */
 227         if ((ssize_t) trigger_comm->length != condition_size + action_size + name_size) {
 228                 ret = -1;
 229                 goto error;
 230         }
 231
 232         *trigger = lttng_trigger_create(condition, action);
 233         if (!*trigger) {
 234                 ret = -1;
 235                 goto error;
 236         }
 237
 238         lttng_trigger_set_credentials(*trigger, &creds);
 239
 240         /*
 241          * The trigger object owns references to the action and condition
 242          * objects.
 243          */
 244         lttng_condition_put(condition);
 245         condition = NULL;
 246
 247         lttng_action_put(action);
 248         action = NULL;
 249
 250         if (name) {
 251                 const enum lttng_trigger_status status =
 252                                 lttng_trigger_set_name(*trigger, name);
 253
 254                 if (status != LTTNG_TRIGGER_STATUS_OK) {
 255                         ret = -1;
 256                         goto end;
 257                 }
 258         }
 259
 260         ret = offset;
 261
 262 error:
 263         lttng_condition_destroy(condition);
 264         lttng_action_destroy(action);
 265 end:
 266         return ret;
 267 }
 268
 269 /*
 270  * Both elements are stored contiguously, see their "*_comm" structure
 271  * for the detailed format.
 272  */
 273 LTTNG_HIDDEN
 274 int lttng_trigger_serialize(const struct lttng_trigger *trigger,
 275                 struct lttng_payload *payload)
 276 {
 277         int ret;
 278         size_t header_offset, size_before_payload, size_name;
 279         struct lttng_trigger_comm trigger_comm = {};
 280         struct lttng_trigger_comm *header;
 281         const struct lttng_credentials *creds = NULL;
 282
 283         creds = lttng_trigger_get_credentials(trigger);
 284         assert(creds);
 285
 286         trigger_comm.uid = LTTNG_OPTIONAL_GET(creds->uid);
 287
 288         if (trigger->name != NULL) {
 289                 size_name = strlen(trigger->name) + 1;
 290         } else {
 291                 size_name = 0;
 292         }
 293
 294         trigger_comm.name_length = size_name;
 295
 296         header_offset = payload->buffer.size;
 297         ret = lttng_dynamic_buffer_append(&payload->buffer, &trigger_comm,
 298                         sizeof(trigger_comm));
 299         if (ret) {
 300                 goto end;
 301         }
 302
 303         size_before_payload = payload->buffer.size;
 304
 305         /* Trigger name. */
 306         ret = lttng_dynamic_buffer_append(
 307                         &payload->buffer, trigger->name, size_name);
 308         if (ret) {
 309                 goto end;
 310         }
 311
 312         ret = lttng_condition_serialize(trigger->condition, payload);
 313         if (ret) {
 314                 goto end;
 315         }
 316
 317         ret = lttng_action_serialize(trigger->action, payload);
 318         if (ret) {
 319                 goto end;
 320         }
 321
 322         /* Update payload size. */
 323         header = (typeof(header)) (payload->buffer.data + header_offset);
 324         header->length = payload->buffer.size - size_before_payload;
 325 end:
 326         return ret;
 327 }
 328
 329 LTTNG_HIDDEN
 330 bool lttng_trigger_is_equal(
 331                 const struct lttng_trigger *a, const struct lttng_trigger *b)
 332 {
 333         /*
 334          * Name is not taken into account since it is cosmetic only.
 335          */
 336         if (!lttng_condition_is_equal(a->condition, b->condition)) {
 337                 return false;
 338         }
 339
 340         if (!lttng_action_is_equal(a->action, b->action)) {
 341                 return false;
 342         }
 343
 344         if (!lttng_credentials_is_equal(lttng_trigger_get_credentials(a),
 345                         lttng_trigger_get_credentials(b))) {
 346                 return false;
 347         }
 348
 349         return true;
 350 }
 351
 352 enum lttng_trigger_status lttng_trigger_set_name(struct lttng_trigger *trigger,
 353                 const char* name)
 354 {
 355         char *name_copy = NULL;
 356         enum lttng_trigger_status status = LTTNG_TRIGGER_STATUS_OK;
 357
 358         if (!trigger || !name ||
 359                         strlen(name) == 0) {
 360                 status = LTTNG_TRIGGER_STATUS_INVALID;
 361                 goto end;
 362         }
 363
 364         name_copy = strdup(name);
 365         if (!name_copy) {
 366                 status = LTTNG_TRIGGER_STATUS_ERROR;
 367                 goto end;
 368         }
 369
 370         free(trigger->name);
 371
 372         trigger->name = name_copy;
 373         name_copy = NULL;
 374 end:
 375         return status;
 376 }
 377
 378 enum lttng_trigger_status lttng_trigger_get_name(
 379                 const struct lttng_trigger *trigger, const char **name)
 380 {
 381         enum lttng_trigger_status status = LTTNG_TRIGGER_STATUS_OK;
 382
 383         if (!trigger || !name) {
 384                 status = LTTNG_TRIGGER_STATUS_INVALID;
 385                 goto end;
 386         }
 387
 388         if (!trigger->name) {
 389                 status = LTTNG_TRIGGER_STATUS_UNSET;
 390         }
 391
 392         *name = trigger->name;
 393 end:
 394         return status;
 395 }
 396
 397 LTTNG_HIDDEN
 398 int lttng_trigger_assign_name(struct lttng_trigger *dst,
 399                 const struct lttng_trigger *src)
 400 {
 401         int ret = 0;
 402         enum lttng_trigger_status status;
 403
 404         status = lttng_trigger_set_name(dst, src->name);
 405         if (status != LTTNG_TRIGGER_STATUS_OK) {
 406                 ret = -1;
 407                 ERR("Failed to set name for trigger");
 408                 goto end;
 409         }
 410 end:
 411         return ret;
 412 }
 413
 414 LTTNG_HIDDEN
 415 void lttng_trigger_set_tracer_token(struct lttng_trigger *trigger,
 416                 uint64_t token)
 417 {
 418         assert(trigger);
 419         LTTNG_OPTIONAL_SET(&trigger->tracer_token, token);
 420 }
 421
 422 LTTNG_HIDDEN
 423 uint64_t lttng_trigger_get_tracer_token(const struct lttng_trigger *trigger)
 424 {
 425         assert(trigger);
 426
 427         return LTTNG_OPTIONAL_GET(trigger->tracer_token);
 428 }
 429
 430 LTTNG_HIDDEN
 431 int lttng_trigger_generate_name(struct lttng_trigger *trigger,
 432                 uint64_t unique_id)
 433 {
 434         int ret = 0;
 435         char *generated_name = NULL;
 436
 437         ret = asprintf(&generated_name, "T%" PRIu64 "", unique_id);
 438         if (ret < 0) {
 439                 ERR("Failed to generate trigger name");
 440                 ret = -1;
 441                 goto end;
 442         }
 443
 444         ret = 0;
 445         free(trigger->name);
 446         trigger->name = generated_name;
 447 end:
 448         return ret;
 449 }
 450
 451 LTTNG_HIDDEN
 452 void lttng_trigger_get(struct lttng_trigger *trigger)
 453 {
 454         urcu_ref_get(&trigger->ref);
 455 }
 456
 457 LTTNG_HIDDEN
 458 void lttng_trigger_put(struct lttng_trigger *trigger)
 459 {
 460         if (!trigger) {
 461                 return;
 462         }
 463
 464         urcu_ref_put(&trigger->ref , trigger_destroy_ref);
 465 }
 466
 467 static void delete_trigger_array_element(void *ptr)
 468 {
 469         struct lttng_trigger *trigger = ptr;
 470
 471         lttng_trigger_put(trigger);
 472 }
 473
 474 LTTNG_HIDDEN
 475 struct lttng_triggers *lttng_triggers_create(void)
 476 {
 477         struct lttng_triggers *triggers = NULL;
 478
 479         triggers = zmalloc(sizeof(*triggers));
 480         if (!triggers) {
 481                 goto end;
 482         }
 483
 484         lttng_dynamic_pointer_array_init(&triggers->array, delete_trigger_array_element);
 485
 486 end:
 487         return triggers;
 488 }
 489
 490 LTTNG_HIDDEN
 491 struct lttng_trigger *lttng_triggers_borrow_mutable_at_index(
 492                 const struct lttng_triggers *triggers, unsigned int index)
 493 {
 494         struct lttng_trigger *trigger = NULL;
 495
 496         assert(triggers);
 497         if (index >= lttng_dynamic_pointer_array_get_count(&triggers->array)) {
 498                 goto end;
 499         }
 500
 501         trigger = (struct lttng_trigger *)
 502                         lttng_dynamic_pointer_array_get_pointer(
 503                                         &triggers->array, index);
 504 end:
 505         return trigger;
 506 }
 507
 508 LTTNG_HIDDEN
 509 int lttng_triggers_add(
 510                 struct lttng_triggers *triggers, struct lttng_trigger *trigger)
 511 {
 512         int ret;
 513
 514         assert(triggers);
 515         assert(trigger);
 516
 517         lttng_trigger_get(trigger);
 518
 519         ret = lttng_dynamic_pointer_array_add_pointer(&triggers->array, trigger);
 520         if (ret) {
 521                 lttng_trigger_put(trigger);
 522         }
 523
 524         return ret;
 525 }
 526
 527 const struct lttng_trigger *lttng_triggers_get_at_index(
 528                 const struct lttng_triggers *triggers, unsigned int index)
 529 {
 530         return lttng_triggers_borrow_mutable_at_index(triggers, index);
 531 }
 532
 533 enum lttng_trigger_status lttng_triggers_get_count(const struct lttng_triggers *triggers, unsigned int *count)
 534 {
 535         enum lttng_trigger_status status = LTTNG_TRIGGER_STATUS_OK;
 536
 537         if (!triggers || !count) {
 538                 status = LTTNG_TRIGGER_STATUS_INVALID;
 539                 goto end;
 540         }
 541
 542         *count = lttng_dynamic_pointer_array_get_count(&triggers->array);
 543 end:
 544         return status;
 545 }
 546
 547 void lttng_triggers_destroy(struct lttng_triggers *triggers)
 548 {
 549         if (!triggers) {
 550                 return;
 551         }
 552
 553         lttng_dynamic_pointer_array_reset(&triggers->array);
 554         free(triggers);
 555 }
 556
 557 int lttng_triggers_serialize(const struct lttng_triggers *triggers,
 558                 struct lttng_payload *payload)
 559 {
 560         int ret;
 561         unsigned int i, count;
 562         size_t size_before_payload;
 563         struct lttng_triggers_comm triggers_comm = {};
 564         struct lttng_triggers_comm *header;
 565         enum lttng_trigger_status status;
 566         const size_t header_offset = payload->buffer.size;
 567
 568         status = lttng_triggers_get_count(triggers, &count);
 569         if (status != LTTNG_TRIGGER_STATUS_OK) {
 570                 ret = LTTNG_ERR_INVALID;
 571                 goto end;
 572         }
 573
 574         triggers_comm.count = count;
 575
 576         /* Placeholder header; updated at the end. */
 577         ret = lttng_dynamic_buffer_append(&payload->buffer, &triggers_comm,
 578                         sizeof(triggers_comm));
 579         if (ret) {
 580                 goto end;
 581         }
 582
 583         size_before_payload = payload->buffer.size;
 584
 585         for (i = 0; i < count; i++) {
 586                 const struct lttng_trigger *trigger =
 587                                 lttng_triggers_get_at_index(triggers, i);
 588
 589                 assert(trigger);
 590
 591                 ret = lttng_trigger_serialize(trigger, payload);
 592                 if (ret) {
 593                         goto end;
 594                 }
 595         }
 596
 597         /* Update payload size. */
 598         header = (struct lttng_triggers_comm *) ((char *) payload->buffer.data + header_offset);
 599         header->length = payload->buffer.size - size_before_payload;
 600 end:
 601         return ret;
 602 }
 603
 604 LTTNG_HIDDEN
 605 ssize_t lttng_triggers_create_from_payload(
 606                 struct lttng_payload_view *src_view,
 607                 struct lttng_triggers **triggers)
 608 {
 609         ssize_t ret, offset = 0, triggers_size = 0;
 610         unsigned int i;
 611         const struct lttng_triggers_comm *triggers_comm;
 612         struct lttng_triggers *local_triggers = NULL;
 613
 614         if (!src_view || !triggers) {
 615                 ret = -1;
 616                 goto error;
 617         }
 618
 619         /* lttng_trigger_comms header */
 620         triggers_comm = (const struct lttng_triggers_comm *) src_view->buffer.data;
 621         offset += sizeof(*triggers_comm);
 622
 623         local_triggers = lttng_triggers_create();
 624         if (!local_triggers) {
 625                 ret = -1;
 626                 goto error;
 627         }
 628
 629         for (i = 0; i < triggers_comm->count; i++) {
 630                 struct lttng_trigger *trigger = NULL;
 631                 struct lttng_payload_view trigger_view =
 632                                 lttng_payload_view_from_view(src_view, offset, -1);
 633                 ssize_t trigger_size;
 634
 635                 trigger_size = lttng_trigger_create_from_payload(
 636                                 &trigger_view, &trigger);
 637                 if (trigger_size < 0) {
 638                         ret = trigger_size;
 639                         goto error;
 640                 }
 641
 642                 /* Transfer ownership of the trigger to the collection. */
 643                 ret = lttng_triggers_add(local_triggers, trigger);
 644                 lttng_trigger_put(trigger);
 645                 if (ret < 0) {
 646                         ret = -1;
 647                         goto error;
 648                 }
 649
 650                 offset += trigger_size;
 651                 triggers_size += trigger_size;
 652         }
 653
 654         /* Unexpected size of inner-elements; the buffer is corrupted. */
 655         if ((ssize_t) triggers_comm->length != triggers_size) {
 656                 ret = -1;
 657                 goto error;
 658         }
 659
 660         /* Pass ownership to caller. */
 661         *triggers = local_triggers;
 662         local_triggers = NULL;
 663
 664         ret = offset;
 665 error:
 666
 667         lttng_triggers_destroy(local_triggers);
 668         return ret;
 669 }
 670
 671 LTTNG_HIDDEN
 672 const struct lttng_credentials *lttng_trigger_get_credentials(
 673                 const struct lttng_trigger *trigger)
 674 {
 675         return &trigger->creds;
 676 }
 677
 678 LTTNG_HIDDEN
 679 void lttng_trigger_set_credentials(struct lttng_trigger *trigger,
 680                 const struct lttng_credentials *creds)
 681 {
 682         assert(creds);
 683         trigger->creds = *creds;
 684 }
 685
 686 enum lttng_trigger_status lttng_trigger_set_owner_uid(
 687                 struct lttng_trigger *trigger, uid_t uid)
 688 {
 689         enum lttng_trigger_status ret = LTTNG_TRIGGER_STATUS_OK;
 690         const struct lttng_credentials creds = {
 691                 .uid = LTTNG_OPTIONAL_INIT_VALUE(uid),
 692                 .gid = LTTNG_OPTIONAL_INIT_UNSET,
 693         };
 694
 695         if (!trigger) {
 696                 ret = LTTNG_TRIGGER_STATUS_INVALID;
 697                 goto end;
 698         }
 699
 700         /* Client-side validation only to report a clearer error. */
 701         if (geteuid() != 0) {
 702                 ret = LTTNG_TRIGGER_STATUS_PERMISSION_DENIED;
 703                 goto end;
 704         }
 705
 706         lttng_trigger_set_credentials(trigger, &creds);
 707
 708 end:
 709         return ret;
 710 }
 711
 712 enum lttng_trigger_status lttng_trigger_get_owner_uid(
 713                 const struct lttng_trigger *trigger, uid_t *uid)
 714 {
 715         enum lttng_trigger_status ret = LTTNG_TRIGGER_STATUS_OK;
 716         const struct lttng_credentials *creds = NULL;
 717
 718         if (!trigger || !uid ) {
 719                 ret = LTTNG_TRIGGER_STATUS_INVALID;
 720                 goto end;
 721         }
 722
 723         if (!trigger->creds.uid.is_set ) {
 724                 ret = LTTNG_TRIGGER_STATUS_UNSET;
 725                 goto end;
 726         }
 727
 728         creds = lttng_trigger_get_credentials(trigger);
 729         *uid = lttng_credentials_get_uid(creds);
 730
 731 end:
 732         return ret;
 733 }