src/common/conditions/buffer-usage.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/condition/condition-internal.h>
   9 #include <lttng/condition/buffer-usage-internal.h>
  10 #include <common/macros.h>
  11 #include <common/error.h>
  12 #include <assert.h>
  13 #include <math.h>
  14 #include <float.h>
  15 #include <time.h>
  16
  17 #define IS_USAGE_CONDITION(condition) ( \
  18         lttng_condition_get_type(condition) == LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW || \
  19         lttng_condition_get_type(condition) == LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH   \
  20         )
  21
  22 static
  23 double fixed_to_double(uint32_t val)
  24 {
  25         return (double) val / (double) UINT32_MAX;
  26 }
  27
  28 static
  29 uint64_t double_to_fixed(double val)
  30 {
  31         return (val * (double) UINT32_MAX);
  32 }
  33
  34 static
  35 bool is_usage_evaluation(const struct lttng_evaluation *evaluation)
  36 {
  37         enum lttng_condition_type type = lttng_evaluation_get_type(evaluation);
  38
  39         return type == LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW ||
  40                         type == LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH;
  41 }
  42
  43 static
  44 void lttng_condition_buffer_usage_destroy(struct lttng_condition *condition)
  45 {
  46         struct lttng_condition_buffer_usage *usage;
  47
  48         usage = container_of(condition, struct lttng_condition_buffer_usage,
  49                         parent);
  50
  51         free(usage->session_name);
  52         free(usage->channel_name);
  53         free(usage);
  54 }
  55
  56 static
  57 bool lttng_condition_buffer_usage_validate(
  58                 const struct lttng_condition *condition)
  59 {
  60         bool valid = false;
  61         struct lttng_condition_buffer_usage *usage;
  62
  63         if (!condition) {
  64                 goto end;
  65         }
  66
  67         usage = container_of(condition, struct lttng_condition_buffer_usage,
  68                         parent);
  69         if (!usage->session_name) {
  70                 ERR("Invalid buffer condition: a target session name must be set.");
  71                 goto end;
  72         }
  73         if (!usage->channel_name) {
  74                 ERR("Invalid buffer condition: a target channel name must be set.");
  75                 goto end;
  76         }
  77         if (!usage->threshold_ratio.set && !usage->threshold_bytes.set) {
  78                 ERR("Invalid buffer condition: a threshold must be set.");
  79                 goto end;
  80         }
  81         if (!usage->domain.set) {
  82                 ERR("Invalid buffer usage condition: a domain must be set.");
  83                 goto end;
  84         }
  85
  86         valid = true;
  87 end:
  88         return valid;
  89 }
  90
  91 static
  92 int lttng_condition_buffer_usage_serialize(
  93                 const struct lttng_condition *condition,
  94                 struct lttng_payload *payload)
  95 {
  96         int ret;
  97         struct lttng_condition_buffer_usage *usage;
  98         size_t session_name_len, channel_name_len;
  99         struct lttng_condition_buffer_usage_comm usage_comm;
 100
 101         if (!condition || !IS_USAGE_CONDITION(condition)) {
 102                 ret = -1;
 103                 goto end;
 104         }
 105
 106         DBG("Serializing buffer usage condition");
 107         usage = container_of(condition, struct lttng_condition_buffer_usage,
 108                         parent);
 109
 110         session_name_len = strlen(usage->session_name) + 1;
 111         channel_name_len = strlen(usage->channel_name) + 1;
 112         if (session_name_len > LTTNG_NAME_MAX ||
 113                         channel_name_len > LTTNG_NAME_MAX) {
 114                 ret = -1;
 115                 goto end;
 116         }
 117
 118         usage_comm.threshold_set_in_bytes = !!usage->threshold_bytes.set;
 119         usage_comm.session_name_len = session_name_len;
 120         usage_comm.channel_name_len = channel_name_len;
 121         usage_comm.domain_type = (int8_t) usage->domain.type;
 122
 123         if (usage->threshold_bytes.set) {
 124                 usage_comm.threshold = usage->threshold_bytes.value;
 125         } else {
 126                 uint64_t val = double_to_fixed(
 127                                 usage->threshold_ratio.value);
 128
 129                 if (val > UINT32_MAX) {
 130                         /* overflow. */
 131                         ret = -1;
 132                         goto end;
 133                 }
 134                 usage_comm.threshold = val;
 135         }
 136
 137         ret = lttng_dynamic_buffer_append(&payload->buffer, &usage_comm,
 138                         sizeof(usage_comm));
 139         if (ret) {
 140                 goto end;
 141         }
 142
 143         ret = lttng_dynamic_buffer_append(&payload->buffer, usage->session_name,
 144                         session_name_len);
 145         if (ret) {
 146                 goto end;
 147         }
 148
 149         ret = lttng_dynamic_buffer_append(&payload->buffer, usage->channel_name,
 150                         channel_name_len);
 151         if (ret) {
 152                 goto end;
 153         }
 154 end:
 155         return ret;
 156 }
 157
 158 static
 159 bool lttng_condition_buffer_usage_is_equal(const struct lttng_condition *_a,
 160                 const struct lttng_condition *_b)
 161 {
 162         bool is_equal = false;
 163         struct lttng_condition_buffer_usage *a, *b;
 164
 165         a = container_of(_a, struct lttng_condition_buffer_usage, parent);
 166         b = container_of(_b, struct lttng_condition_buffer_usage, parent);
 167
 168         if ((a->threshold_ratio.set && !b->threshold_ratio.set) ||
 169                         (a->threshold_bytes.set && !b->threshold_bytes.set)) {
 170                 goto end;
 171         }
 172
 173         if (a->threshold_ratio.set && b->threshold_ratio.set) {
 174                 double a_value, b_value, diff;
 175
 176                 a_value = a->threshold_ratio.value;
 177                 b_value = b->threshold_ratio.value;
 178                 diff = fabs(a_value - b_value);
 179
 180                 if (diff > DBL_EPSILON) {
 181                         goto end;
 182                 }
 183         } else if (a->threshold_bytes.set && b->threshold_bytes.set) {
 184                 uint64_t a_value, b_value;
 185
 186                 a_value = a->threshold_bytes.value;
 187                 b_value = b->threshold_bytes.value;
 188                 if (a_value != b_value) {
 189                         goto end;
 190                 }
 191         }
 192
 193         /* Condition is not valid if this is not true. */
 194         assert(a->session_name);
 195         assert(b->session_name);
 196         if (strcmp(a->session_name, b->session_name)) {
 197                 goto end;
 198         }
 199
 200         assert(a->channel_name);
 201         assert(b->channel_name);
 202         if (strcmp(a->channel_name, b->channel_name)) {
 203                 goto end;
 204         }
 205
 206         assert(a->domain.set);
 207         assert(b->domain.set);
 208         if (a->domain.type != b->domain.type) {
 209                 goto end;
 210         }
 211         is_equal = true;
 212 end:
 213         return is_equal;
 214 }
 215
 216 static
 217 struct lttng_condition *lttng_condition_buffer_usage_create(
 218                 enum lttng_condition_type type)
 219 {
 220         struct lttng_condition_buffer_usage *condition;
 221
 222         condition = zmalloc(sizeof(struct lttng_condition_buffer_usage));
 223         if (!condition) {
 224                 return NULL;
 225         }
 226
 227         lttng_condition_init(&condition->parent, type);
 228         condition->parent.validate = lttng_condition_buffer_usage_validate;
 229         condition->parent.serialize = lttng_condition_buffer_usage_serialize;
 230         condition->parent.equal = lttng_condition_buffer_usage_is_equal;
 231         condition->parent.destroy = lttng_condition_buffer_usage_destroy;
 232         return &condition->parent;
 233 }
 234
 235 struct lttng_condition *lttng_condition_buffer_usage_low_create(void)
 236 {
 237         return lttng_condition_buffer_usage_create(
 238                         LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW);
 239 }
 240
 241 struct lttng_condition *lttng_condition_buffer_usage_high_create(void)
 242 {
 243         return lttng_condition_buffer_usage_create(
 244                         LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH);
 245 }
 246
 247 static
 248 ssize_t init_condition_from_payload(struct lttng_condition *condition,
 249                 struct lttng_payload_view *src_view)
 250 {
 251         ssize_t ret, condition_size;
 252         enum lttng_condition_status status;
 253         enum lttng_domain_type domain_type;
 254         const char *session_name, *channel_name;
 255         struct lttng_buffer_view names_view;
 256         const struct lttng_condition_buffer_usage_comm *condition_comm;
 257         const struct lttng_payload_view condition_comm_view =
 258                         lttng_payload_view_from_view(
 259                                         src_view, 0, sizeof(*condition_comm));
 260
 261         if (!lttng_payload_view_is_valid(&condition_comm_view)) {
 262                 ERR("Failed to initialize from malformed condition buffer: buffer too short to contain header");
 263                 ret = -1;
 264                 goto end;
 265         }
 266
 267         condition_comm = (typeof(condition_comm)) condition_comm_view.buffer.data;
 268         names_view = lttng_buffer_view_from_view(&src_view->buffer,
 269                         sizeof(*condition_comm), -1);
 270
 271         if (condition_comm->session_name_len > LTTNG_NAME_MAX ||
 272                         condition_comm->channel_name_len > LTTNG_NAME_MAX) {
 273                 ERR("Failed to initialize from malformed condition buffer: name exceeds LTTNG_MAX_NAME");
 274                 ret = -1;
 275                 goto end;
 276         }
 277
 278         if (names_view.size <
 279                         (condition_comm->session_name_len +
 280                         condition_comm->channel_name_len)) {
 281                 ERR("Failed to initialize from malformed condition buffer: buffer too short to contain element names");
 282                 ret = -1;
 283                 goto end;
 284         }
 285
 286         if (condition_comm->threshold_set_in_bytes) {
 287                 status = lttng_condition_buffer_usage_set_threshold(condition,
 288                                 condition_comm->threshold);
 289         } else {
 290                 status = lttng_condition_buffer_usage_set_threshold_ratio(
 291                                 condition,
 292                                 fixed_to_double(condition_comm->threshold));
 293         }
 294
 295         if (status != LTTNG_CONDITION_STATUS_OK) {
 296                 ERR("Failed to initialize buffer usage condition threshold");
 297                 ret = -1;
 298                 goto end;
 299         }
 300
 301         if (condition_comm->domain_type <= LTTNG_DOMAIN_NONE ||
 302                         condition_comm->domain_type > LTTNG_DOMAIN_PYTHON) {
 303                 /* Invalid domain value. */
 304                 ERR("Invalid domain type value (%i) found in condition buffer",
 305                                 (int) condition_comm->domain_type);
 306                 ret = -1;
 307                 goto end;
 308         }
 309
 310         domain_type = (enum lttng_domain_type) condition_comm->domain_type;
 311         status = lttng_condition_buffer_usage_set_domain_type(condition,
 312                         domain_type);
 313         if (status != LTTNG_CONDITION_STATUS_OK) {
 314                 ERR("Failed to set buffer usage condition domain");
 315                 ret = -1;
 316                 goto end;
 317         }
 318
 319         session_name = names_view.data;
 320         if (*(session_name + condition_comm->session_name_len - 1) != '\0') {
 321                 ERR("Malformed session name encountered in condition buffer");
 322                 ret = -1;
 323                 goto end;
 324         }
 325
 326         channel_name = session_name + condition_comm->session_name_len;
 327         if (*(channel_name + condition_comm->channel_name_len - 1) != '\0') {
 328                 ERR("Malformed channel name encountered in condition buffer");
 329                 ret = -1;
 330                 goto end;
 331         }
 332
 333         status = lttng_condition_buffer_usage_set_session_name(condition,
 334                         session_name);
 335         if (status != LTTNG_CONDITION_STATUS_OK) {
 336                 ERR("Failed to set buffer usage session name");
 337                 ret = -1;
 338                 goto end;
 339         }
 340
 341         status = lttng_condition_buffer_usage_set_channel_name(condition,
 342                         channel_name);
 343         if (status != LTTNG_CONDITION_STATUS_OK) {
 344                 ERR("Failed to set buffer usage channel name");
 345                 ret = -1;
 346                 goto end;
 347         }
 348
 349         if (!lttng_condition_validate(condition)) {
 350                 ret = -1;
 351                 goto end;
 352         }
 353
 354         condition_size = sizeof(*condition_comm) +
 355                         (ssize_t) condition_comm->session_name_len +
 356                         (ssize_t) condition_comm->channel_name_len;
 357         ret = condition_size;
 358 end:
 359         return ret;
 360 }
 361
 362 LTTNG_HIDDEN
 363 ssize_t lttng_condition_buffer_usage_low_create_from_payload(
 364                 struct lttng_payload_view *view,
 365                 struct lttng_condition **_condition)
 366 {
 367         ssize_t ret;
 368         struct lttng_condition *condition =
 369                         lttng_condition_buffer_usage_low_create();
 370
 371         if (!_condition || !condition) {
 372                 ret = -1;
 373                 goto error;
 374         }
 375
 376         ret = init_condition_from_payload(condition, view);
 377         if (ret < 0) {
 378                 goto error;
 379         }
 380
 381         *_condition = condition;
 382         return ret;
 383 error:
 384         lttng_condition_destroy(condition);
 385         return ret;
 386 }
 387
 388 LTTNG_HIDDEN
 389 ssize_t lttng_condition_buffer_usage_high_create_from_payload(
 390                 struct lttng_payload_view *view,
 391                 struct lttng_condition **_condition)
 392 {
 393         ssize_t ret;
 394         struct lttng_condition *condition =
 395                         lttng_condition_buffer_usage_high_create();
 396
 397         if (!_condition || !condition) {
 398                 ret = -1;
 399                 goto error;
 400         }
 401
 402         ret = init_condition_from_payload(condition, view);
 403         if (ret < 0) {
 404                 goto error;
 405         }
 406
 407         *_condition = condition;
 408         return ret;
 409 error:
 410         lttng_condition_destroy(condition);
 411         return ret;
 412 }
 413
 414 static
 415 struct lttng_evaluation *create_evaluation_from_payload(
 416                 enum lttng_condition_type type,
 417                 struct lttng_payload_view *view)
 418 {
 419         const struct lttng_evaluation_buffer_usage_comm *comm =
 420                         (typeof(comm)) view->buffer.data;
 421         struct lttng_evaluation *evaluation = NULL;
 422
 423         if (view->buffer.size < sizeof(*comm)) {
 424                 goto end;
 425         }
 426
 427         evaluation = lttng_evaluation_buffer_usage_create(type,
 428                         comm->buffer_use, comm->buffer_capacity);
 429 end:
 430         return evaluation;
 431 }
 432
 433 LTTNG_HIDDEN
 434 ssize_t lttng_evaluation_buffer_usage_low_create_from_payload(
 435                 struct lttng_payload_view *view,
 436                 struct lttng_evaluation **_evaluation)
 437 {
 438         ssize_t ret;
 439         struct lttng_evaluation *evaluation = NULL;
 440
 441         if (!_evaluation) {
 442                 ret = -1;
 443                 goto error;
 444         }
 445
 446         evaluation = create_evaluation_from_payload(
 447                         LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW, view);
 448         if (!evaluation) {
 449                 ret = -1;
 450                 goto error;
 451         }
 452
 453         *_evaluation = evaluation;
 454         ret = sizeof(struct lttng_evaluation_buffer_usage_comm);
 455         return ret;
 456 error:
 457         lttng_evaluation_destroy(evaluation);
 458         return ret;
 459 }
 460
 461 LTTNG_HIDDEN
 462 ssize_t lttng_evaluation_buffer_usage_high_create_from_payload(
 463                 struct lttng_payload_view *view,
 464                 struct lttng_evaluation **_evaluation)
 465 {
 466         ssize_t ret;
 467         struct lttng_evaluation *evaluation = NULL;
 468
 469         if (!_evaluation) {
 470                 ret = -1;
 471                 goto error;
 472         }
 473
 474         evaluation = create_evaluation_from_payload(
 475                         LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH, view);
 476         if (!evaluation) {
 477                 ret = -1;
 478                 goto error;
 479         }
 480
 481         *_evaluation = evaluation;
 482         ret = sizeof(struct lttng_evaluation_buffer_usage_comm);
 483         return ret;
 484 error:
 485         lttng_evaluation_destroy(evaluation);
 486         return ret;
 487 }
 488
 489 enum lttng_condition_status
 490 lttng_condition_buffer_usage_get_threshold_ratio(
 491                 const struct lttng_condition *condition,
 492                 double *threshold_ratio)
 493 {
 494         struct lttng_condition_buffer_usage *usage;
 495         enum lttng_condition_status status = LTTNG_CONDITION_STATUS_OK;
 496
 497         if (!condition || !IS_USAGE_CONDITION(condition) ||
 498                         !threshold_ratio) {
 499                 status = LTTNG_CONDITION_STATUS_INVALID;
 500                 goto end;
 501         }
 502
 503         usage = container_of(condition, struct lttng_condition_buffer_usage,
 504                         parent);
 505         if (!usage->threshold_ratio.set) {
 506                 status = LTTNG_CONDITION_STATUS_UNSET;
 507                 goto end;
 508         }
 509         *threshold_ratio = usage->threshold_ratio.value;
 510 end:
 511         return status;
 512 }
 513
 514 /* threshold_ratio expressed as [0.0, 1.0]. */
 515 enum lttng_condition_status
 516 lttng_condition_buffer_usage_set_threshold_ratio(
 517                 struct lttng_condition *condition, double threshold_ratio)
 518 {
 519         struct lttng_condition_buffer_usage *usage;
 520         enum lttng_condition_status status = LTTNG_CONDITION_STATUS_OK;
 521
 522         if (!condition || !IS_USAGE_CONDITION(condition) ||
 523                         threshold_ratio < 0.0 ||
 524                         threshold_ratio > 1.0) {
 525                 status = LTTNG_CONDITION_STATUS_INVALID;
 526                 goto end;
 527         }
 528
 529         usage = container_of(condition, struct lttng_condition_buffer_usage,
 530                         parent);
 531         usage->threshold_ratio.set = true;
 532         usage->threshold_bytes.set = false;
 533         usage->threshold_ratio.value = threshold_ratio;
 534 end:
 535         return status;
 536 }
 537
 538 enum lttng_condition_status
 539 lttng_condition_buffer_usage_get_threshold(
 540                 const struct lttng_condition *condition,
 541                 uint64_t *threshold_bytes)
 542 {
 543         struct lttng_condition_buffer_usage *usage;
 544         enum lttng_condition_status status = LTTNG_CONDITION_STATUS_OK;
 545
 546         if (!condition || !IS_USAGE_CONDITION(condition) || !threshold_bytes) {
 547                 status = LTTNG_CONDITION_STATUS_INVALID;
 548                 goto end;
 549         }
 550
 551         usage = container_of(condition, struct lttng_condition_buffer_usage,
 552                         parent);
 553         if (!usage->threshold_bytes.set) {
 554                 status = LTTNG_CONDITION_STATUS_UNSET;
 555                 goto end;
 556         }
 557         *threshold_bytes = usage->threshold_bytes.value;
 558 end:
 559         return status;
 560 }
 561
 562 enum lttng_condition_status
 563 lttng_condition_buffer_usage_set_threshold(
 564                 struct lttng_condition *condition, uint64_t threshold_bytes)
 565 {
 566         struct lttng_condition_buffer_usage *usage;
 567         enum lttng_condition_status status = LTTNG_CONDITION_STATUS_OK;
 568
 569         if (!condition || !IS_USAGE_CONDITION(condition)) {
 570                 status = LTTNG_CONDITION_STATUS_INVALID;
 571                 goto end;
 572         }
 573
 574         usage = container_of(condition, struct lttng_condition_buffer_usage,
 575                         parent);
 576         usage->threshold_ratio.set = false;
 577         usage->threshold_bytes.set = true;
 578         usage->threshold_bytes.value = threshold_bytes;
 579 end:
 580         return status;
 581 }
 582
 583 enum lttng_condition_status
 584 lttng_condition_buffer_usage_get_session_name(
 585                 const struct lttng_condition *condition,
 586                 const char **session_name)
 587 {
 588         struct lttng_condition_buffer_usage *usage;
 589         enum lttng_condition_status status = LTTNG_CONDITION_STATUS_OK;
 590
 591         if (!condition || !IS_USAGE_CONDITION(condition) || !session_name) {
 592                 status = LTTNG_CONDITION_STATUS_INVALID;
 593                 goto end;
 594         }
 595
 596         usage = container_of(condition, struct lttng_condition_buffer_usage,
 597                         parent);
 598         if (!usage->session_name) {
 599                 status = LTTNG_CONDITION_STATUS_UNSET;
 600                 goto end;
 601         }
 602         *session_name = usage->session_name;
 603 end:
 604         return status;
 605 }
 606
 607 enum lttng_condition_status
 608 lttng_condition_buffer_usage_set_session_name(
 609                 struct lttng_condition *condition, const char *session_name)
 610 {
 611         char *session_name_copy;
 612         struct lttng_condition_buffer_usage *usage;
 613         enum lttng_condition_status status = LTTNG_CONDITION_STATUS_OK;
 614
 615         if (!condition || !IS_USAGE_CONDITION(condition) || !session_name ||
 616                         strlen(session_name) == 0) {
 617                 status = LTTNG_CONDITION_STATUS_INVALID;
 618                 goto end;
 619         }
 620
 621         usage = container_of(condition, struct lttng_condition_buffer_usage,
 622                         parent);
 623         session_name_copy = strdup(session_name);
 624         if (!session_name_copy) {
 625                 status = LTTNG_CONDITION_STATUS_ERROR;
 626                 goto end;
 627         }
 628
 629         if (usage->session_name) {
 630                 free(usage->session_name);
 631         }
 632         usage->session_name = session_name_copy;
 633 end:
 634         return status;
 635 }
 636
 637 enum lttng_condition_status
 638 lttng_condition_buffer_usage_get_channel_name(
 639                 const struct lttng_condition *condition,
 640                 const char **channel_name)
 641 {
 642         struct lttng_condition_buffer_usage *usage;
 643         enum lttng_condition_status status = LTTNG_CONDITION_STATUS_OK;
 644
 645         if (!condition || !IS_USAGE_CONDITION(condition) || !channel_name) {
 646                 status = LTTNG_CONDITION_STATUS_INVALID;
 647                 goto end;
 648         }
 649
 650         usage = container_of(condition, struct lttng_condition_buffer_usage,
 651                         parent);
 652         if (!usage->channel_name) {
 653                 status = LTTNG_CONDITION_STATUS_UNSET;
 654                 goto end;
 655         }
 656         *channel_name = usage->channel_name;
 657 end:
 658         return status;
 659 }
 660
 661 enum lttng_condition_status
 662 lttng_condition_buffer_usage_set_channel_name(
 663                 struct lttng_condition *condition, const char *channel_name)
 664 {
 665         char *channel_name_copy;
 666         struct lttng_condition_buffer_usage *usage;
 667         enum lttng_condition_status status = LTTNG_CONDITION_STATUS_OK;
 668
 669         if (!condition || !IS_USAGE_CONDITION(condition) || !channel_name ||
 670                         strlen(channel_name) == 0) {
 671                 status = LTTNG_CONDITION_STATUS_INVALID;
 672                 goto end;
 673         }
 674
 675         usage = container_of(condition, struct lttng_condition_buffer_usage,
 676                         parent);
 677         channel_name_copy = strdup(channel_name);
 678         if (!channel_name_copy) {
 679                 status = LTTNG_CONDITION_STATUS_ERROR;
 680                 goto end;
 681         }
 682
 683         if (usage->channel_name) {
 684                 free(usage->channel_name);
 685         }
 686         usage->channel_name = channel_name_copy;
 687 end:
 688         return status;
 689 }
 690
 691 enum lttng_condition_status
 692 lttng_condition_buffer_usage_get_domain_type(
 693                 const struct lttng_condition *condition,
 694                 enum lttng_domain_type *type)
 695 {
 696         struct lttng_condition_buffer_usage *usage;
 697         enum lttng_condition_status status = LTTNG_CONDITION_STATUS_OK;
 698
 699         if (!condition || !IS_USAGE_CONDITION(condition) || !type) {
 700                 status = LTTNG_CONDITION_STATUS_INVALID;
 701                 goto end;
 702         }
 703
 704         usage = container_of(condition, struct lttng_condition_buffer_usage,
 705                         parent);
 706         if (!usage->domain.set) {
 707                 status = LTTNG_CONDITION_STATUS_UNSET;
 708                 goto end;
 709         }
 710         *type = usage->domain.type;
 711 end:
 712         return status;
 713 }
 714
 715 enum lttng_condition_status
 716 lttng_condition_buffer_usage_set_domain_type(
 717                 struct lttng_condition *condition, enum lttng_domain_type type)
 718 {
 719         struct lttng_condition_buffer_usage *usage;
 720         enum lttng_condition_status status = LTTNG_CONDITION_STATUS_OK;
 721
 722         if (!condition || !IS_USAGE_CONDITION(condition) ||
 723                         type == LTTNG_DOMAIN_NONE) {
 724                 status = LTTNG_CONDITION_STATUS_INVALID;
 725                 goto end;
 726         }
 727
 728         usage = container_of(condition, struct lttng_condition_buffer_usage,
 729                         parent);
 730         usage->domain.set = true;
 731         usage->domain.type = type;
 732 end:
 733         return status;
 734 }
 735
 736 static
 737 int lttng_evaluation_buffer_usage_serialize(
 738                 const struct lttng_evaluation *evaluation,
 739                 struct lttng_payload *payload)
 740 {
 741         struct lttng_evaluation_buffer_usage *usage;
 742         struct lttng_evaluation_buffer_usage_comm comm;
 743
 744         usage = container_of(evaluation, struct lttng_evaluation_buffer_usage,
 745                         parent);
 746         comm.buffer_use = usage->buffer_use;
 747         comm.buffer_capacity = usage->buffer_capacity;
 748
 749         return lttng_dynamic_buffer_append(
 750                         &payload->buffer, &comm, sizeof(comm));
 751 }
 752
 753 static
 754 void lttng_evaluation_buffer_usage_destroy(
 755                 struct lttng_evaluation *evaluation)
 756 {
 757         struct lttng_evaluation_buffer_usage *usage;
 758
 759         usage = container_of(evaluation, struct lttng_evaluation_buffer_usage,
 760                         parent);
 761         free(usage);
 762 }
 763
 764 LTTNG_HIDDEN
 765 struct lttng_evaluation *lttng_evaluation_buffer_usage_create(
 766                 enum lttng_condition_type type, uint64_t use, uint64_t capacity)
 767 {
 768         struct lttng_evaluation_buffer_usage *usage;
 769
 770         usage = zmalloc(sizeof(struct lttng_evaluation_buffer_usage));
 771         if (!usage) {
 772                 goto end;
 773         }
 774
 775         usage->parent.type = type;
 776         usage->buffer_use = use;
 777         usage->buffer_capacity = capacity;
 778         usage->parent.serialize = lttng_evaluation_buffer_usage_serialize;
 779         usage->parent.destroy = lttng_evaluation_buffer_usage_destroy;
 780 end:
 781         return &usage->parent;
 782 }
 783
 784 /*
 785  * Get the sampled buffer usage which caused the associated condition to
 786  * evaluate to "true".
 787  */
 788 enum lttng_evaluation_status
 789 lttng_evaluation_buffer_usage_get_usage_ratio(
 790                 const struct lttng_evaluation *evaluation, double *usage_ratio)
 791 {
 792         struct lttng_evaluation_buffer_usage *usage;
 793         enum lttng_evaluation_status status = LTTNG_EVALUATION_STATUS_OK;
 794
 795         if (!evaluation || !is_usage_evaluation(evaluation) || !usage_ratio) {
 796                 status = LTTNG_EVALUATION_STATUS_INVALID;
 797                 goto end;
 798         }
 799
 800         usage = container_of(evaluation, struct lttng_evaluation_buffer_usage,
 801                         parent);
 802         *usage_ratio = (double) usage->buffer_use /
 803                         (double) usage->buffer_capacity;
 804 end:
 805         return status;
 806 }
 807
 808 enum lttng_evaluation_status
 809 lttng_evaluation_buffer_usage_get_usage(
 810                 const struct lttng_evaluation *evaluation,
 811                 uint64_t *usage_bytes)
 812 {
 813         struct lttng_evaluation_buffer_usage *usage;
 814         enum lttng_evaluation_status status = LTTNG_EVALUATION_STATUS_OK;
 815
 816         if (!evaluation || !is_usage_evaluation(evaluation) || !usage_bytes) {
 817                 status = LTTNG_EVALUATION_STATUS_INVALID;
 818                 goto end;
 819         }
 820
 821         usage = container_of(evaluation, struct lttng_evaluation_buffer_usage,
 822                         parent);
 823         *usage_bytes = usage->buffer_use;
 824 end:
 825         return status;
 826 }