src/common/event.cpp

   1 /*
   2  * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #include <common/align.hpp>
   9 #include <common/buffer-view.hpp>
  10 #include <common/compat/string.hpp>
  11 #include <common/dynamic-array.hpp>
  12 #include <common/dynamic-buffer.hpp>
  13 #include <common/error.hpp>
  14 #include <common/macros.hpp>
  15 #include <common/sessiond-comm/sessiond-comm.hpp>
  16
  17 #include <lttng/constant.h>
  18 #include <lttng/event-internal.hpp>
  19 #include <lttng/event.h>
  20 #include <lttng/lttng-error.h>
  21 #include <lttng/userspace-probe-internal.hpp>
  22
  23 namespace {
  24 struct event_list_element {
  25         struct lttng_event *event;
  26         struct lttng_event_exclusion *exclusions;
  27         char *filter_expression;
  28 };
  29 } /* namespace */
  30
  31 static void event_list_destructor(void *ptr)
  32 {
  33         struct event_list_element *element = (struct event_list_element *) ptr;
  34
  35         free(element->filter_expression);
  36         free(element->exclusions);
  37         lttng_event_destroy(element->event);
  38         free(element);
  39 }
  40
  41 struct lttng_event *lttng_event_copy(const struct lttng_event *event)
  42 {
  43         struct lttng_event *new_event;
  44         struct lttng_event_extended *new_event_extended;
  45
  46         new_event = zmalloc<lttng_event>();
  47         if (!new_event) {
  48                 PERROR("Error allocating event structure");
  49                 goto end;
  50         }
  51
  52         /* Copy the content of the old event. */
  53         memcpy(new_event, event, sizeof(*event));
  54
  55         /*
  56          * We need to create a new extended since the previous pointer is now
  57          * invalid.
  58          */
  59         new_event_extended = zmalloc<lttng_event_extended>();
  60         if (!new_event_extended) {
  61                 PERROR("Error allocating event extended structure");
  62                 goto error;
  63         }
  64
  65         new_event->extended.ptr = new_event_extended;
  66 end:
  67         return new_event;
  68 error:
  69         free(new_event);
  70         new_event = NULL;
  71         goto end;
  72 }
  73
  74 static int lttng_event_probe_attr_serialize(
  75                 const struct lttng_event_probe_attr *probe,
  76                 struct lttng_payload *payload)
  77 {
  78         int ret;
  79         size_t symbol_name_len;
  80         struct lttng_event_probe_attr_comm comm = {};
  81
  82         symbol_name_len = lttng_strnlen(
  83                         probe->symbol_name, sizeof(probe->symbol_name));
  84         if (symbol_name_len == sizeof(probe->symbol_name)) {
  85                 /* Not null-termintated. */
  86                 ret = -1;
  87                 goto end;
  88         }
  89
  90         /* Include the null terminator. */
  91         symbol_name_len += 1;
  92
  93         comm.symbol_name_len = (uint32_t) symbol_name_len;
  94         comm.addr = probe->addr;
  95         comm.offset = probe->addr;
  96
  97         ret = lttng_dynamic_buffer_append(
  98                         &payload->buffer, &comm, sizeof(comm));
  99         if (ret < 0) {
 100                 ret = -1;
 101                 goto end;
 102         }
 103
 104         ret = lttng_dynamic_buffer_append(
 105                         &payload->buffer, probe->symbol_name, symbol_name_len);
 106 end:
 107         return ret;
 108 }
 109
 110 static int lttng_event_function_attr_serialize(
 111                 const struct lttng_event_function_attr *function,
 112                 struct lttng_payload *payload)
 113 {
 114         int ret;
 115         size_t symbol_name_len;
 116         struct lttng_event_function_attr_comm comm;
 117
 118         comm.symbol_name_len = 0;
 119
 120         symbol_name_len = lttng_strnlen(
 121                         function->symbol_name, sizeof(function->symbol_name));
 122         if (symbol_name_len == sizeof(function->symbol_name)) {
 123                 /* Not null-termintated. */
 124                 ret = -1;
 125                 goto end;
 126         }
 127
 128         /* Include the null terminator. */
 129         symbol_name_len += 1;
 130
 131         comm.symbol_name_len = (uint32_t) symbol_name_len;
 132
 133         ret = lttng_dynamic_buffer_append(
 134                         &payload->buffer, &comm, sizeof(comm));
 135         if (ret < 0) {
 136                 ret = -1;
 137                 goto end;
 138         }
 139
 140         ret = lttng_dynamic_buffer_append(&payload->buffer,
 141                         function->symbol_name, symbol_name_len);
 142 end:
 143         return ret;
 144 }
 145
 146 static ssize_t lttng_event_probe_attr_create_from_payload(
 147                 struct lttng_payload_view *view,
 148                 struct lttng_event_probe_attr **probe_attr)
 149 {
 150         ssize_t ret, offset = 0;
 151         const struct lttng_event_probe_attr_comm *comm;
 152         struct lttng_event_probe_attr *local_attr = NULL;
 153         struct lttng_payload_view comm_view = lttng_payload_view_from_view(
 154                         view, offset, sizeof(*comm));
 155
 156         if (!lttng_payload_view_is_valid(&comm_view)) {
 157                 ret = -1;
 158                 goto end;
 159         }
 160
 161         comm = (typeof(comm)) comm_view.buffer.data;
 162         offset += sizeof(*comm);
 163
 164         local_attr = zmalloc<lttng_event_probe_attr>();
 165         if (local_attr == NULL) {
 166                 ret = -1;
 167                 goto end;
 168         }
 169
 170         local_attr->addr = comm->addr;
 171         local_attr->offset = comm->offset;
 172
 173         {
 174                 const char *name;
 175                 struct lttng_payload_view name_view =
 176                                 lttng_payload_view_from_view(view, offset,
 177                                                 comm->symbol_name_len);
 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
 186                 if (!lttng_buffer_view_contains_string(&name_view.buffer, name,
 187                                     comm->symbol_name_len)) {
 188                         ret = -1;
 189                         goto end;
 190                 }
 191
 192                 ret = lttng_strncpy(local_attr->symbol_name, name,
 193                                 sizeof(local_attr->symbol_name));
 194                 if (ret) {
 195                         ret = -1;
 196                         goto end;
 197                 }
 198
 199                 offset += comm->symbol_name_len;
 200         }
 201
 202         *probe_attr = local_attr;
 203         local_attr = NULL;
 204         ret = offset;
 205 end:
 206         free(local_attr);
 207         return ret;
 208 }
 209
 210 static ssize_t lttng_event_function_attr_create_from_payload(
 211                 struct lttng_payload_view *view,
 212                 struct lttng_event_function_attr **function_attr)
 213 {
 214         ssize_t ret, offset = 0;
 215         const struct lttng_event_function_attr_comm *comm;
 216         struct lttng_event_function_attr *local_attr = NULL;
 217         struct lttng_payload_view comm_view = lttng_payload_view_from_view(
 218                         view, offset, sizeof(*comm));
 219
 220         if (!lttng_payload_view_is_valid(&comm_view)) {
 221                 ret = -1;
 222                 goto end;
 223         }
 224
 225         comm = (typeof(comm)) view->buffer.data;
 226         offset += sizeof(*comm);
 227
 228         local_attr = zmalloc<lttng_event_function_attr>();
 229         if (local_attr == NULL) {
 230                 ret = -1;
 231                 goto end;
 232         }
 233
 234         {
 235                 const char *name;
 236                 struct lttng_payload_view name_view =
 237                                 lttng_payload_view_from_view(view, offset,
 238                                                 comm->symbol_name_len);
 239
 240                 if (!lttng_payload_view_is_valid(&name_view)) {
 241                         ret = -1;
 242                         goto end;
 243                 }
 244
 245                 name = name_view.buffer.data;
 246
 247                 if (!lttng_buffer_view_contains_string(&name_view.buffer, name,
 248                                     comm->symbol_name_len)) {
 249                         ret = -1;
 250                         goto end;
 251                 }
 252
 253                 ret = lttng_strncpy(local_attr->symbol_name, name,
 254                                 sizeof(local_attr->symbol_name));
 255                 if (ret) {
 256                         ret = -1;
 257                         goto end;
 258                 }
 259
 260                 offset += comm->symbol_name_len;
 261         }
 262
 263         *function_attr = local_attr;
 264         local_attr = NULL;
 265         ret = offset;
 266 end:
 267         free(local_attr);
 268         return ret;
 269 }
 270
 271 static ssize_t lttng_event_exclusions_create_from_payload(
 272                 struct lttng_payload_view *view,
 273                 uint32_t count,
 274                 struct lttng_event_exclusion **exclusions)
 275 {
 276         ssize_t ret, offset = 0;
 277         const size_t size = (count * LTTNG_SYMBOL_NAME_LEN);
 278         uint32_t i;
 279         const struct lttng_event_exclusion_comm *comm;
 280         struct lttng_event_exclusion *local_exclusions;
 281
 282         local_exclusions = zmalloc<lttng_event_exclusion>(
 283                         sizeof(struct lttng_event_exclusion) + size);
 284         if (!local_exclusions) {
 285                 ret = -1;
 286                 goto end;
 287         }
 288
 289         local_exclusions->count = count;
 290
 291         for (i = 0; i < count; i++) {
 292                 const char *string;
 293                 struct lttng_buffer_view string_view;
 294                 const struct lttng_buffer_view comm_view =
 295                                 lttng_buffer_view_from_view(&view->buffer,
 296                                                 offset, sizeof(*comm));
 297
 298                 if (!lttng_buffer_view_is_valid(&comm_view)) {
 299                         ret = -1;
 300                         goto end;
 301                 }
 302
 303                 comm = (typeof(comm)) comm_view.data;
 304                 offset += sizeof(*comm);
 305
 306                 string_view = lttng_buffer_view_from_view(
 307                                 &view->buffer, offset, comm->len);
 308
 309                 if (!lttng_buffer_view_is_valid(&string_view)) {
 310                         ret = -1;
 311                         goto end;
 312                 }
 313
 314                 string = string_view.data;
 315
 316                 if (!lttng_buffer_view_contains_string(
 317                                     &string_view, string, comm->len)) {
 318                         ret = -1;
 319                         goto end;
 320                 }
 321
 322                 ret = lttng_strncpy(LTTNG_EVENT_EXCLUSION_NAME_AT(local_exclusions, i), string,
 323                                 sizeof(LTTNG_EVENT_EXCLUSION_NAME_AT(local_exclusions, i)));
 324                 if (ret) {
 325                         ret = -1;
 326                         goto end;
 327                 }
 328
 329                 offset += comm->len;
 330         }
 331
 332         *exclusions = local_exclusions;
 333         local_exclusions = NULL;
 334         ret = offset;
 335 end:
 336         free(local_exclusions);
 337         return ret;
 338 }
 339
 340 ssize_t lttng_event_create_from_payload(struct lttng_payload_view *view,
 341                 struct lttng_event **out_event,
 342                 struct lttng_event_exclusion **out_exclusion,
 343                 char **out_filter_expression,
 344                 struct lttng_bytecode **out_bytecode)
 345 {
 346         ssize_t ret, offset = 0;
 347         struct lttng_event *local_event = NULL;
 348         struct lttng_event_exclusion *local_exclusions = NULL;
 349         struct lttng_bytecode *local_bytecode = NULL;
 350         char *local_filter_expression = NULL;
 351         const struct lttng_event_comm *event_comm;
 352         struct lttng_event_function_attr *local_function_attr = NULL;
 353         struct lttng_event_probe_attr *local_probe_attr = NULL;
 354         struct lttng_userspace_probe_location *local_userspace_probe_location =
 355                         NULL;
 356
 357         /*
 358          * Only event is obligatory, the other output argument are optional and
 359          * depends on what the caller is interested in.
 360          */
 361         assert(out_event);
 362         assert(view);
 363
 364         {
 365                 struct lttng_payload_view comm_view =
 366                                 lttng_payload_view_from_view(view, offset,
 367                                                 sizeof(*event_comm));
 368
 369                 if (!lttng_payload_view_is_valid(&comm_view)) {
 370                         ret = -1;
 371                         goto end;
 372                 }
 373
 374                 /* lttng_event_comm header */
 375                 event_comm = (typeof(event_comm)) comm_view.buffer.data;
 376                 offset += sizeof(*event_comm);
 377         }
 378
 379         local_event = lttng_event_create();
 380         if (local_event == NULL) {
 381                 ret = -1;
 382                 goto end;
 383         }
 384
 385         local_event->type = (enum lttng_event_type) event_comm->event_type;
 386         local_event->loglevel_type = (enum lttng_loglevel_type) event_comm->loglevel_type;
 387         local_event->loglevel = event_comm->loglevel;
 388         local_event->enabled = event_comm->enabled;
 389         local_event->pid = event_comm->pid;
 390         local_event->flags = (enum lttng_event_flag) event_comm->flags;
 391
 392         {
 393                 const char *name;
 394                 const struct lttng_buffer_view name_view =
 395                                 lttng_buffer_view_from_view(&view->buffer,
 396                                                 offset, event_comm->name_len);
 397
 398                 if (!lttng_buffer_view_is_valid(&name_view)) {
 399                         ret = -1;
 400                         goto end;
 401                 }
 402
 403                 name = (const char *) name_view.data;
 404
 405                 if (!lttng_buffer_view_contains_string(
 406                                     &name_view, name, event_comm->name_len)) {
 407                         ret = -1;
 408                         goto end;
 409                 }
 410
 411                 ret = lttng_strncpy(local_event->name, name,
 412                                 sizeof(local_event->name));
 413                 if (ret) {
 414                         ret = -1;
 415                         goto end;
 416                 }
 417
 418                 offset += event_comm->name_len;
 419         }
 420
 421         /* Exclusions */
 422         if (event_comm->exclusion_count == 0) {
 423                 goto deserialize_filter_expression;
 424         }
 425
 426         {
 427                 struct lttng_payload_view exclusions_view =
 428                                 lttng_payload_view_from_view(
 429                                                 view, offset, -1);
 430
 431                 if (!lttng_payload_view_is_valid(&exclusions_view)) {
 432                         ret = -1;
 433                         goto end;
 434                 }
 435
 436                 ret = lttng_event_exclusions_create_from_payload(&exclusions_view,
 437                                 event_comm->exclusion_count, &local_exclusions);
 438                 if (ret < 0) {
 439                         ret = -1;
 440                         goto end;
 441                 }
 442                 offset += ret;
 443
 444                 local_event->exclusion = 1;
 445         }
 446
 447 deserialize_filter_expression:
 448
 449         if (event_comm->filter_expression_len == 0) {
 450                 if (event_comm->bytecode_len != 0) {
 451                         /*
 452                          * This is an invalid event payload.
 453                          *
 454                          * Filter expression without bytecode is possible but
 455                          * not the other way around.
 456                          * */
 457                         ret = -1;
 458                         goto end;
 459                 }
 460                 goto deserialize_event_type_payload;
 461         }
 462
 463         {
 464                 const char *filter_expression_buffer;
 465                 struct lttng_buffer_view filter_expression_view =
 466                                 lttng_buffer_view_from_view(&view->buffer, offset,
 467                                                 event_comm->filter_expression_len);
 468
 469                 if (!lttng_buffer_view_is_valid(&filter_expression_view)) {
 470                         ret = -1;
 471                         goto end;
 472                 }
 473
 474                 filter_expression_buffer = filter_expression_view.data;
 475
 476                 if (!lttng_buffer_view_contains_string(&filter_expression_view,
 477                                     filter_expression_buffer,
 478                                     event_comm->filter_expression_len)) {
 479                         ret = -1;
 480                         goto end;
 481                 }
 482
 483                 local_filter_expression = lttng_strndup(
 484                                 filter_expression_buffer,
 485                                 event_comm->filter_expression_len);
 486                 if (!local_filter_expression) {
 487                         ret = -1;
 488                         goto end;
 489                 }
 490
 491                 local_event->filter = 1;
 492
 493                 offset += event_comm->filter_expression_len;
 494         }
 495
 496         if (event_comm->bytecode_len == 0) {
 497                 /*
 498                  * Filter expression can be present but without bytecode
 499                  * when dealing with event listing.
 500                  */
 501                 goto deserialize_event_type_payload;
 502         }
 503
 504         /* Bytecode */
 505         {
 506                 struct lttng_payload_view bytecode_view =
 507                                 lttng_payload_view_from_view(view, offset,
 508                                                 event_comm->bytecode_len);
 509
 510                 if (!lttng_payload_view_is_valid(&bytecode_view)) {
 511                         ret = -1;
 512                         goto end;
 513                 }
 514
 515                 local_bytecode = zmalloc<lttng_bytecode>(event_comm->bytecode_len);
 516                 if (!local_bytecode) {
 517                         ret = -1;
 518                         goto end;
 519                 }
 520
 521                 memcpy(local_bytecode, bytecode_view.buffer.data,
 522                                 event_comm->bytecode_len);
 523                 if ((local_bytecode->len + sizeof(*local_bytecode)) !=
 524                                 event_comm->bytecode_len) {
 525                         ret = -1;
 526                         goto end;
 527                 }
 528
 529                 offset += event_comm->bytecode_len;
 530         }
 531
 532 deserialize_event_type_payload:
 533         /* Event type specific payload */
 534         switch (local_event->type) {
 535         case LTTNG_EVENT_FUNCTION:
 536                 /* Fallthrough */
 537         case LTTNG_EVENT_PROBE:
 538         {
 539                 struct lttng_payload_view probe_attr_view =
 540                                 lttng_payload_view_from_view(view, offset,
 541                                                 event_comm->lttng_event_probe_attr_len);
 542
 543                 if (event_comm->lttng_event_probe_attr_len == 0) {
 544                         ret = -1;
 545                         goto end;
 546                 }
 547
 548                 if (!lttng_payload_view_is_valid(&probe_attr_view)) {
 549                         ret = -1;
 550                         goto end;
 551                 }
 552
 553                 ret = lttng_event_probe_attr_create_from_payload(
 554                                 &probe_attr_view, &local_probe_attr);
 555                 if (ret < 0 || ret != event_comm->lttng_event_probe_attr_len) {
 556                         ret = -1;
 557                         goto end;
 558                 }
 559
 560                 /* Copy to the local event. */
 561                 memcpy(&local_event->attr.probe, local_probe_attr,
 562                                 sizeof(local_event->attr.probe));
 563
 564                 offset += ret;
 565                 break;
 566         }
 567         case LTTNG_EVENT_FUNCTION_ENTRY:
 568         {
 569                 struct lttng_payload_view function_attr_view =
 570                                 lttng_payload_view_from_view(view, offset,
 571                                                 event_comm->lttng_event_function_attr_len);
 572
 573                 if (event_comm->lttng_event_function_attr_len == 0) {
 574                         ret = -1;
 575                         goto end;
 576                 }
 577
 578                 if (!lttng_payload_view_is_valid(&function_attr_view)) {
 579                         ret = -1;
 580                         goto end;
 581                 }
 582
 583                 ret = lttng_event_function_attr_create_from_payload(
 584                                 &function_attr_view, &local_function_attr);
 585                 if (ret < 0 || ret != event_comm->lttng_event_function_attr_len) {
 586                         ret = -1;
 587                         goto end;
 588                 }
 589
 590                 /* Copy to the local event. */
 591                 memcpy(&local_event->attr.ftrace, local_function_attr,
 592                                 sizeof(local_event->attr.ftrace));
 593
 594                 offset += ret;
 595
 596                 break;
 597         }
 598         case LTTNG_EVENT_USERSPACE_PROBE:
 599         {
 600                 struct lttng_payload_view userspace_probe_location_view =
 601                                 lttng_payload_view_from_view(view, offset,
 602                                                 event_comm->userspace_probe_location_len);
 603
 604                 if (event_comm->userspace_probe_location_len == 0) {
 605                         ret = -1;
 606                         goto end;
 607                 }
 608
 609                 if (!lttng_payload_view_is_valid(
 610                                     &userspace_probe_location_view)) {
 611                         ret = -1;
 612                         goto end;
 613                 }
 614
 615                 ret = lttng_userspace_probe_location_create_from_payload(
 616                                 &userspace_probe_location_view,
 617                                 &local_userspace_probe_location);
 618                 if (ret < 0) {
 619                         WARN("Failed to create a userspace probe location from the received buffer");
 620                         ret = -1;
 621                         goto end;
 622                 }
 623
 624                 if (ret != event_comm->userspace_probe_location_len) {
 625                         WARN("Userspace probe location from the received buffer is not the advertised length: header length = %" PRIu32 ", payload length = %zd", event_comm->userspace_probe_location_len, ret);
 626                         ret = -1;
 627                         goto end;
 628                 }
 629
 630                 /* Attach the probe location to the event. */
 631                 ret = lttng_event_set_userspace_probe_location(
 632                                 local_event, local_userspace_probe_location);
 633                 if (ret) {
 634                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 635                         goto end;
 636                 }
 637
 638                 /*
 639                  * Userspace probe location object ownership transfered to the
 640                  * event object.
 641                  */
 642                 local_userspace_probe_location = NULL;
 643                 offset += event_comm->userspace_probe_location_len;
 644                 break;
 645         }
 646         case LTTNG_EVENT_TRACEPOINT:
 647                 /* Fallthrough */
 648         case LTTNG_EVENT_ALL:
 649                 /* Fallthrough */
 650         case LTTNG_EVENT_SYSCALL:
 651                 /* Fallthrough */
 652         case LTTNG_EVENT_NOOP:
 653                 /* Nothing to do here */
 654                 break;
 655         default:
 656                 ret = LTTNG_ERR_UND;
 657                 goto end;
 658                 break;
 659         }
 660
 661         /* Transfer ownership to the caller. */
 662         *out_event = local_event;
 663         local_event = NULL;
 664
 665         if (out_bytecode) {
 666                 *out_bytecode = local_bytecode;
 667                 local_bytecode = NULL;
 668         }
 669
 670         if (out_exclusion) {
 671                 *out_exclusion = local_exclusions;
 672                 local_exclusions = NULL;
 673         }
 674
 675         if (out_filter_expression) {
 676                 *out_filter_expression = local_filter_expression;
 677                 local_filter_expression = NULL;
 678         }
 679
 680         ret = offset;
 681 end:
 682         lttng_event_destroy(local_event);
 683         lttng_userspace_probe_location_destroy(local_userspace_probe_location);
 684         free(local_filter_expression);
 685         free(local_exclusions);
 686         free(local_bytecode);
 687         free(local_function_attr);
 688         free(local_probe_attr);
 689         return ret;
 690 }
 691
 692 int lttng_event_serialize(const struct lttng_event *event,
 693                 unsigned int exclusion_count,
 694                 char **exclusion_list,
 695                 char *filter_expression,
 696                 size_t bytecode_len,
 697                 struct lttng_bytecode *bytecode,
 698                 struct lttng_payload *payload)
 699 {
 700         int ret;
 701         unsigned int i;
 702         size_t header_offset, size_before_payload;
 703         size_t name_len;
 704         struct lttng_event_comm event_comm = {};
 705         struct lttng_event_comm *header;
 706
 707         assert(event);
 708         assert(payload);
 709         assert(exclusion_count == 0 || exclusion_list);
 710
 711         /* Save the header location for later in-place header update. */
 712         header_offset = payload->buffer.size;
 713
 714         name_len = lttng_strnlen(event->name, sizeof(event->name));
 715         if (name_len == sizeof(event->name)) {
 716                 /* Event name is not NULL-terminated. */
 717                 ret = -1;
 718                 goto end;
 719         }
 720
 721         /* Add null termination. */
 722         name_len += 1;
 723
 724         if (exclusion_count > UINT32_MAX) {
 725                 /* Possible overflow. */
 726                 ret = -1;
 727                 goto end;
 728         }
 729
 730         if (bytecode_len > UINT32_MAX) {
 731                 /* Possible overflow. */
 732                 ret = -1;
 733                 goto end;
 734         }
 735
 736         event_comm.name_len = (uint32_t) name_len;
 737         event_comm.event_type = (int8_t) event->type;
 738         event_comm.loglevel_type = (int8_t) event->loglevel_type;
 739         event_comm.loglevel = (int32_t) event->loglevel;
 740         event_comm.enabled = (int8_t) event->enabled;
 741         event_comm.pid = (int32_t) event->pid;
 742         event_comm.exclusion_count = (uint32_t) exclusion_count;
 743         event_comm.bytecode_len = (uint32_t) bytecode_len;
 744         event_comm.flags = (int32_t) event->flags;
 745
 746         if (filter_expression) {
 747                 event_comm.filter_expression_len =
 748                                 strlen(filter_expression) + 1;
 749         }
 750
 751         /* Header */
 752         ret = lttng_dynamic_buffer_append(
 753                         &payload->buffer, &event_comm, sizeof(event_comm));
 754         if (ret) {
 755                 goto end;
 756         }
 757
 758         /* Event name */
 759         ret = lttng_dynamic_buffer_append(
 760                         &payload->buffer, event->name, name_len);
 761         if (ret) {
 762                 goto end;
 763         }
 764
 765         /* Exclusions */
 766         for (i = 0; i < exclusion_count; i++) {
 767                 const size_t exclusion_len = lttng_strnlen(
 768                                 *(exclusion_list + i), LTTNG_SYMBOL_NAME_LEN);
 769                 const struct lttng_event_exclusion_comm exclusion_header = {
 770                         .len = (uint32_t) exclusion_len + 1,
 771                 };
 772
 773                 if (exclusion_len == LTTNG_SYMBOL_NAME_LEN) {
 774                         /* Exclusion is not NULL-terminated. */
 775                         ret = -1;
 776                         goto end;
 777                 }
 778
 779                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 780                                 &exclusion_header, sizeof(exclusion_header));
 781                 if (ret) {
 782                         goto end;
 783                 }
 784
 785                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 786                                 *(exclusion_list + i), exclusion_len + 1);
 787                 if (ret) {
 788                         goto end;
 789                 }
 790         }
 791
 792         /* Filter expression and its bytecode */
 793         if (filter_expression) {
 794                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 795                                 filter_expression,
 796                                 event_comm.filter_expression_len);
 797                 if (ret) {
 798                         goto end;
 799                 }
 800
 801                 /*
 802                  * Bytecode can be absent when we serialize to the client
 803                  * for listing.
 804                  */
 805                 if (bytecode) {
 806                         ret = lttng_dynamic_buffer_append(&payload->buffer,
 807                                         bytecode, bytecode_len);
 808                         if (ret) {
 809                                 goto end;
 810                         }
 811                 }
 812         }
 813
 814         size_before_payload = payload->buffer.size;
 815
 816         /* Event type specific payload */
 817         switch (event->type) {
 818         case LTTNG_EVENT_FUNCTION:
 819                 /* Fallthrough */
 820         case LTTNG_EVENT_PROBE:
 821                 ret = lttng_event_probe_attr_serialize(&event->attr.probe, payload);
 822                 if (ret) {
 823                         ret = -1;
 824                         goto end;
 825                 }
 826
 827                 header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 828                                                       header_offset);
 829                 header->lttng_event_probe_attr_len =
 830                                 payload->buffer.size - size_before_payload;
 831
 832                 break;
 833         case LTTNG_EVENT_FUNCTION_ENTRY:
 834                 ret = lttng_event_function_attr_serialize(
 835                                 &event->attr.ftrace, payload);
 836                 if (ret) {
 837                         ret = -1;
 838                         goto end;
 839                 }
 840
 841                 /* Update the lttng_event_function_attr len. */
 842                 header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 843                                                       header_offset);
 844                 header->lttng_event_function_attr_len =
 845                                 payload->buffer.size - size_before_payload;
 846
 847                 break;
 848         case LTTNG_EVENT_USERSPACE_PROBE:
 849         {
 850                 const struct lttng_event_extended *ev_ext =
 851                                 (const struct lttng_event_extended *)
 852                                                 event->extended.ptr;
 853
 854                 assert(event->extended.ptr);
 855                 assert(ev_ext->probe_location);
 856
 857                 size_before_payload = payload->buffer.size;
 858                 if (ev_ext->probe_location) {
 859                         /*
 860                          * lttng_userspace_probe_location_serialize returns the
 861                          * number of bytes that were appended to the buffer.
 862                          */
 863                         ret = lttng_userspace_probe_location_serialize(
 864                                         ev_ext->probe_location, payload);
 865                         if (ret < 0) {
 866                                 goto end;
 867                         }
 868
 869                         ret = 0;
 870
 871                         /* Update the userspace probe location len. */
 872                         header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 873                                                               header_offset);
 874                         header->userspace_probe_location_len =
 875                                         payload->buffer.size - size_before_payload;
 876                 }
 877                 break;
 878         }
 879         case LTTNG_EVENT_TRACEPOINT:
 880                 /* Fallthrough */
 881         case LTTNG_EVENT_ALL:
 882                 /* Fallthrough */
 883         default:
 884                 /* Nothing to do here. */
 885                 break;
 886         }
 887
 888 end:
 889         return ret;
 890 }
 891
 892 static ssize_t lttng_event_context_app_populate_from_payload(
 893                 const struct lttng_payload_view *view,
 894                 struct lttng_event_context *event_ctx)
 895 {
 896         ssize_t ret, offset = 0;
 897         const struct lttng_event_context_app_comm *comm;
 898         char *provider_name = NULL, *context_name = NULL;
 899         size_t provider_name_len, context_name_len;
 900         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
 901                         &view->buffer, offset, sizeof(*comm));
 902
 903         assert(event_ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
 904
 905         if (!lttng_buffer_view_is_valid(&comm_view)) {
 906                 ret = -1;
 907                 goto end;
 908         }
 909
 910         comm = (typeof(comm)) comm_view.data;
 911         offset += sizeof(*comm);
 912
 913         provider_name_len = comm->provider_name_len;
 914         context_name_len = comm->ctx_name_len;
 915
 916         if (provider_name_len == 0 || context_name_len == 0) {
 917                 /*
 918                  * Application provider and context names MUST
 919                  * be provided.
 920                  */
 921                 ret = -1;
 922                 goto end;
 923         }
 924
 925         {
 926                 const char *name;
 927                 const struct lttng_buffer_view provider_name_view =
 928                                 lttng_buffer_view_from_view(&view->buffer,
 929                                                 offset,
 930                                                 provider_name_len);
 931
 932                 if (!lttng_buffer_view_is_valid(&provider_name_view)) {
 933                         ret = -1;
 934                         goto end;
 935                 }
 936
 937                 name = provider_name_view.data;
 938
 939                 if (!lttng_buffer_view_contains_string(&provider_name_view,
 940                                 name, provider_name_len)) {
 941                         ret = -1;
 942                         goto end;
 943                 }
 944
 945                 provider_name = lttng_strndup(name, provider_name_len);
 946                 if (!provider_name) {
 947                         ret = -1;
 948                         goto end;
 949                 }
 950
 951                 offset += provider_name_len;
 952         }
 953
 954         {
 955                 const char *name;
 956                 const struct lttng_buffer_view context_name_view =
 957                                 lttng_buffer_view_from_view(
 958                                                 &view->buffer, offset,
 959                                                 context_name_len);
 960
 961                 if (!lttng_buffer_view_is_valid(&context_name_view)) {
 962                         ret = -1;
 963                         goto end;
 964                 }
 965
 966                 name = context_name_view.data;
 967
 968                 if (!lttng_buffer_view_contains_string(&context_name_view, name,
 969                                     context_name_len)) {
 970                         ret = -1;
 971                         goto end;
 972                 }
 973
 974                 context_name = lttng_strndup(name, context_name_len);
 975                 if (!context_name) {
 976                         ret = -1;
 977                         goto end;
 978                 }
 979
 980                 offset += context_name_len;
 981         }
 982
 983         /* Transfer ownership of the strings */
 984         event_ctx->u.app_ctx.provider_name = provider_name;
 985         event_ctx->u.app_ctx.ctx_name = context_name;
 986         provider_name = NULL;
 987         context_name = NULL;
 988
 989         ret = offset;
 990 end:
 991         free(provider_name);
 992         free(context_name);
 993
 994         return ret;
 995 }
 996
 997 static ssize_t lttng_event_context_perf_counter_populate_from_payload(
 998                 const struct lttng_payload_view *view,
 999                 struct lttng_event_context *event_ctx)
1000 {
1001         int ret;
1002         ssize_t consumed, offset = 0;
1003         const struct lttng_event_context_perf_counter_comm *comm;
1004         size_t name_len;
1005         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
1006                         &view->buffer, offset, sizeof(*comm));
1007
1008         assert(event_ctx->ctx == LTTNG_EVENT_CONTEXT_PERF_COUNTER ||
1009                         event_ctx->ctx ==
1010                                         LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER ||
1011                         event_ctx->ctx == LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER);
1012
1013         if (!lttng_buffer_view_is_valid(&comm_view)) {
1014                 consumed = -1;
1015                 goto end;
1016         }
1017
1018         comm = (typeof(comm)) comm_view.data;
1019         offset += sizeof(*comm);
1020
1021         name_len = comm->name_len;
1022
1023         {
1024                 const char *name;
1025                 const struct lttng_buffer_view provider_name_view =
1026                                 lttng_buffer_view_from_view(
1027                                                 &view->buffer, offset,
1028                                                 name_len);
1029
1030                 if (!lttng_buffer_view_is_valid(&provider_name_view)) {
1031                         consumed = -1;
1032                         goto end;
1033                 }
1034
1035                 name = provider_name_view.data;
1036
1037                 if (!lttng_buffer_view_contains_string(
1038                                     &provider_name_view, name, name_len)) {
1039                         consumed = -1;
1040                         goto end;
1041                 }
1042
1043                 ret = lttng_strncpy(event_ctx->u.perf_counter.name, name,
1044                                 sizeof(event_ctx->u.perf_counter.name));
1045                 if (ret) {
1046                         consumed = -1;
1047                         goto end;
1048                 }
1049                 offset += name_len;
1050         }
1051
1052         event_ctx->u.perf_counter.config = comm->config;
1053         event_ctx->u.perf_counter.type = comm->type;
1054
1055         consumed = offset;
1056
1057 end:
1058         return consumed;
1059 }
1060
1061 ssize_t lttng_event_context_create_from_payload(
1062                 struct lttng_payload_view *view,
1063                 struct lttng_event_context **event_ctx)
1064 {
1065         ssize_t ret, offset = 0;
1066         const struct lttng_event_context_comm *comm;
1067         struct lttng_event_context *local_context = NULL;
1068         struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
1069                         &view->buffer, offset, sizeof(*comm));
1070
1071         assert(event_ctx);
1072         assert(view);
1073
1074         if (!lttng_buffer_view_is_valid(&comm_view)) {
1075                 ret = -1;
1076                 goto end;
1077         }
1078
1079         comm = (typeof(comm)) comm_view.data;
1080         offset += sizeof(*comm);
1081
1082         local_context = zmalloc<lttng_event_context>();
1083         if (!local_context) {
1084                 ret = -1;
1085                 goto end;
1086         }
1087
1088         local_context->ctx = (lttng_event_context_type) comm->type;
1089
1090         {
1091                 struct lttng_payload_view subtype_view =
1092                                 lttng_payload_view_from_view(view, offset, -1);
1093
1094                 switch (local_context->ctx) {
1095                 case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1096                         ret = lttng_event_context_app_populate_from_payload(
1097                                         &subtype_view, local_context);
1098                         break;
1099                 case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1100                 case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1101                 case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1102                         ret = lttng_event_context_perf_counter_populate_from_payload(
1103                                         &subtype_view, local_context);
1104                         break;
1105                 default:
1106                         /* Nothing else to deserialize. */
1107                         ret = 0;
1108                         break;
1109                 }
1110         }
1111
1112         if (ret < 0) {
1113                 goto end;
1114         }
1115
1116         offset += ret;
1117
1118         *event_ctx = local_context;
1119         local_context = NULL;
1120         ret = offset;
1121
1122 end:
1123         free(local_context);
1124         return ret;
1125 }
1126
1127 static int lttng_event_context_app_serialize(
1128                 struct lttng_event_context *context,
1129                 struct lttng_payload *payload)
1130 {
1131         int ret;
1132         struct lttng_event_context_app_comm comm = {};
1133         size_t provider_len, ctx_len;
1134         const char *provider_name;
1135         const char *ctx_name;
1136
1137         assert(payload);
1138         assert(context);
1139         assert(context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
1140
1141         provider_name = context->u.app_ctx.provider_name;
1142         ctx_name = context->u.app_ctx.ctx_name;
1143
1144         if (!provider_name || !ctx_name) {
1145                 ret = -LTTNG_ERR_INVALID;
1146                 goto end;
1147         }
1148
1149         provider_len = strlen(provider_name);
1150         if (provider_len == 0) {
1151                 ret = -LTTNG_ERR_INVALID;
1152                 goto end;
1153         }
1154
1155         /* Include the null terminator. */
1156         provider_len += 1;
1157         comm.provider_name_len = provider_len;
1158
1159         ctx_len = strlen(ctx_name);
1160         if (ctx_len == 0) {
1161                 ret = -LTTNG_ERR_INVALID;
1162                 goto end;
1163         }
1164
1165         /* Include the null terminator. */
1166         ctx_len += 1;
1167         comm.ctx_name_len = ctx_len;
1168
1169         /* Header */
1170         ret = lttng_dynamic_buffer_append(&payload->buffer, &comm,
1171                         sizeof(comm));
1172         if (ret) {
1173                 ret = -1;
1174                 goto end;
1175         }
1176
1177         ret = lttng_dynamic_buffer_append(&payload->buffer, provider_name,
1178                         provider_len);
1179         if (ret) {
1180                 ret = -1;
1181                 goto end;
1182         }
1183
1184         ret = lttng_dynamic_buffer_append(&payload->buffer, ctx_name,
1185                         ctx_len);
1186         if (ret) {
1187                 ret = -1;
1188                 goto end;
1189         }
1190
1191 end:
1192         return ret;
1193 }
1194
1195 static int lttng_event_context_perf_counter_serialize(
1196                 struct lttng_event_perf_counter_ctx *context,
1197                 struct lttng_payload *payload)
1198 {
1199         int ret;
1200         struct lttng_event_context_perf_counter_comm comm = {};
1201
1202         assert(payload);
1203         assert(context);
1204
1205         comm.config = context->config;
1206         comm.type = context->type;
1207         comm.name_len = lttng_strnlen(context->name, sizeof(context->name));
1208
1209         if (comm.name_len == sizeof(context->name)) {
1210                 ret = -1;
1211                 goto end;
1212         }
1213
1214         /* Include the null terminator. */
1215         comm.name_len += 1;
1216
1217         /* Header */
1218         ret = lttng_dynamic_buffer_append(&payload->buffer, &comm,
1219                         sizeof(comm));
1220         if (ret) {
1221                 ret = -1;
1222                 goto end;
1223         }
1224
1225         ret = lttng_dynamic_buffer_append(&payload->buffer, context->name,
1226                         comm.name_len);
1227         if (ret) {
1228                 ret = -1;
1229                 goto end;
1230         }
1231
1232 end:
1233         return ret;
1234 }
1235
1236 int lttng_event_context_serialize(struct lttng_event_context *context,
1237                 struct lttng_payload *payload)
1238 {
1239         int ret;
1240         struct lttng_event_context_comm context_comm = { 0 };
1241
1242         assert(context);
1243         assert(payload);
1244
1245         context_comm.type = (uint32_t) context->ctx;
1246
1247         /* Header */
1248         ret = lttng_dynamic_buffer_append(
1249                         &payload->buffer, &context_comm, sizeof(context_comm));
1250         if (ret) {
1251                 goto end;
1252         }
1253
1254         switch (context->ctx) {
1255         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1256                 ret = lttng_event_context_app_serialize(context, payload);
1257                 break;
1258         case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1259         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1260         case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1261                 ret = lttng_event_context_perf_counter_serialize(
1262                                 &context->u.perf_counter, payload);
1263                 break;
1264         default:
1265                 /* Nothing else to serialize. */
1266                 break;
1267         }
1268
1269         if (ret) {
1270                 goto end;
1271         }
1272
1273 end:
1274         return ret;
1275 }
1276
1277 void lttng_event_context_destroy(struct lttng_event_context *context)
1278 {
1279         if (!context) {
1280                 return;
1281         }
1282
1283         if (context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
1284                 free(context->u.app_ctx.provider_name);
1285                 free(context->u.app_ctx.ctx_name);
1286         }
1287
1288         free(context);
1289 }
1290
1291 /*
1292  * This is a specialized populate for lttng_event_field since it ignores
1293  * the extension field of the lttng_event struct and simply copies what it can
1294  * to the internal struct lttng_event of a lttng_event_field.
1295  */
1296 static void lttng_event_field_populate_lttng_event_from_event(
1297                 const struct lttng_event *src, struct lttng_event *destination)
1298 {
1299         memcpy(destination, src, sizeof(*destination));
1300
1301         /* Remove all possible dynamic data from the destination event rule. */
1302         destination->extended.ptr = NULL;
1303 }
1304
1305 ssize_t lttng_event_field_create_from_payload(
1306                 struct lttng_payload_view *view,
1307                 struct lttng_event_field **field)
1308 {
1309         ssize_t ret, offset = 0;
1310         struct lttng_event_field *local_event_field = NULL;
1311         struct lttng_event *event = NULL;
1312         const struct lttng_event_field_comm *comm;
1313         const char* name = NULL;
1314
1315         assert(field);
1316         assert(view);
1317
1318         {
1319                 const struct lttng_buffer_view comm_view =
1320                                 lttng_buffer_view_from_view(
1321                                                 &view->buffer, offset,
1322                                                 sizeof(*comm));
1323
1324                 if (!lttng_buffer_view_is_valid(&comm_view)) {
1325                         ret = -1;
1326                         goto end;
1327                 }
1328
1329                 /* lttng_event_field_comm header */
1330                 comm = (const lttng_event_field_comm *) comm_view.data;
1331                 offset += sizeof(*comm);
1332         }
1333
1334         local_event_field = zmalloc<lttng_event_field>();
1335         if (!local_event_field) {
1336                 ret = -1;
1337                 goto end;
1338         }
1339
1340         local_event_field->type = (lttng_event_field_type) comm->type;
1341         local_event_field->nowrite = comm->nowrite;
1342
1343         /* Field name */
1344         {
1345                 const struct lttng_buffer_view name_view =
1346                                 lttng_buffer_view_from_view(
1347                                                 &view->buffer, offset,
1348                                                 comm->name_len);
1349
1350                 if (!lttng_buffer_view_is_valid(&name_view)) {
1351                         ret = -1;
1352                         goto end;
1353                 }
1354
1355                 name = name_view.data;
1356
1357                 if (!lttng_buffer_view_contains_string(&name_view,
1358                                 name_view.data, comm->name_len)) {
1359                         ret = -1;
1360                         goto end;
1361                 }
1362
1363                 if (comm->name_len > LTTNG_SYMBOL_NAME_LEN - 1) {
1364                         /* Name is too long.*/
1365                         ret = -1;
1366                         goto end;
1367                 }
1368
1369                 offset += comm->name_len;
1370         }
1371
1372         /* Event */
1373         {
1374                 struct lttng_payload_view event_view =
1375                                 lttng_payload_view_from_view(
1376                                                 view, offset,
1377                                                 comm->event_len);
1378
1379                 if (!lttng_payload_view_is_valid(&event_view)) {
1380                         ret = -1;
1381                         goto end;
1382                 }
1383
1384                 ret = lttng_event_create_from_payload(&event_view, &event, NULL,
1385                                 NULL, NULL);
1386                 if (ret != comm->event_len) {
1387                         ret = -1;
1388                         goto end;
1389                 }
1390
1391                 offset += ret;
1392         }
1393
1394         assert(name);
1395         assert(event);
1396
1397         if (lttng_strncpy(local_event_field->field_name, name,
1398                         sizeof(local_event_field->field_name))) {
1399                 ret = -1;
1400                 goto end;
1401         }
1402
1403         lttng_event_field_populate_lttng_event_from_event(
1404                         event, &local_event_field->event);
1405
1406         *field = local_event_field;
1407         local_event_field = NULL;
1408         ret = offset;
1409 end:
1410         lttng_event_destroy(event);
1411         free(local_event_field);
1412         return ret;
1413 }
1414
1415 int lttng_event_field_serialize(const struct lttng_event_field *field,
1416                 struct lttng_payload *payload)
1417 {
1418         int ret;
1419         size_t header_offset, size_before_event;
1420         size_t name_len;
1421         struct lttng_event_field_comm event_field_comm = {};
1422         struct lttng_event_field_comm *header;
1423
1424         assert(field);
1425         assert(payload);
1426
1427         /* Save the header location for later in-place header update. */
1428         header_offset = payload->buffer.size;
1429
1430         name_len = strnlen(field->field_name, sizeof(field->field_name));
1431         if (name_len == sizeof(field->field_name)) {
1432                 /* Event name is not NULL-terminated. */
1433                 ret = -1;
1434                 goto end;
1435         }
1436
1437         /* Add null termination. */
1438         name_len += 1;
1439
1440         event_field_comm.type = field->type;
1441         event_field_comm.nowrite = (uint8_t)field->nowrite;
1442         event_field_comm.name_len = name_len;
1443
1444         /* Header */
1445         ret = lttng_dynamic_buffer_append(
1446                         &payload->buffer, &event_field_comm,
1447                         sizeof(event_field_comm));
1448         if (ret) {
1449                 goto end;
1450         }
1451
1452         /* Field name */
1453         ret = lttng_dynamic_buffer_append(&payload->buffer, field->field_name,
1454                         name_len);
1455         if (ret) {
1456                 goto end;
1457         }
1458
1459         size_before_event = payload->buffer.size;
1460         ret = lttng_event_serialize(
1461                         &field->event, 0, NULL, NULL, 0, 0, payload);
1462         if (ret) {
1463                 ret = -1;
1464                 goto end;
1465         }
1466
1467         /* Update the event len. */
1468         header = (struct lttng_event_field_comm *)
1469                         ((char *) payload->buffer.data +
1470                                 header_offset);
1471         header->event_len = payload->buffer.size - size_before_event;
1472
1473 end:
1474         return ret;
1475 }
1476
1477 static enum lttng_error_code compute_flattened_size(
1478                 struct lttng_dynamic_pointer_array *events, size_t *size)
1479 {
1480         enum lttng_error_code ret_code;
1481         int ret = 0;
1482         size_t storage_req, event_count, i;
1483
1484         assert(size);
1485         assert(events);
1486
1487         event_count = lttng_dynamic_pointer_array_get_count(events);
1488
1489         /* The basic struct lttng_event */
1490         storage_req = event_count * sizeof(struct lttng_event);
1491
1492         /* The struct·lttng_event_extended */
1493         storage_req += event_count * sizeof(struct lttng_event_extended);
1494
1495         for (i = 0; i < event_count; i++) {
1496                 int probe_storage_req = 0;
1497                 const struct event_list_element *element = (const struct event_list_element *)
1498                                 lttng_dynamic_pointer_array_get_pointer(
1499                                                 events, i);
1500                 const struct lttng_userspace_probe_location *location = NULL;
1501
1502                 location = lttng_event_get_userspace_probe_location(
1503                                 element->event);
1504                 if (location) {
1505                         ret = lttng_userspace_probe_location_flatten(
1506                                         location, NULL);
1507                         if (ret < 0) {
1508                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1509                                 goto end;
1510                         }
1511
1512                         probe_storage_req = ret;
1513                 }
1514
1515                 if (element->filter_expression) {
1516                         storage_req += strlen(element->filter_expression) + 1;
1517                 }
1518
1519                 if (element->exclusions) {
1520                         storage_req += element->exclusions->count *
1521                                 LTTNG_SYMBOL_NAME_LEN;
1522                 }
1523
1524                 /* Padding to ensure the flat probe is aligned. */
1525                 storage_req = lttng_align_ceil(storage_req, sizeof(uint64_t));
1526                 storage_req += probe_storage_req;
1527         }
1528
1529         *size = storage_req;
1530         ret_code = LTTNG_OK;
1531
1532 end:
1533         return ret_code;
1534 }
1535
1536 /*
1537  * Flatten a list of struct lttng_event.
1538  *
1539  * The buffer that is returned to the API client  must contain a "flat" version
1540  * of the events that are returned. In other words, all pointers within an
1541  * lttng_event must point to a location within the returned buffer so that the
1542  * user may free everything by simply calling free() on the returned buffer.
1543  * This is needed in order to maintain API compatibility.
1544  *
1545  * A first pass is performed to compute the size of the buffer that must be
1546  * allocated. A second pass is then performed to setup the returned events so
1547  * that their members always point within the buffer.
1548  *
1549  * The layout of the returned buffer is as follows:
1550  *   - struct lttng_event[nb_events],
1551  *   - nb_events times the following:
1552  *     - struct lttng_event_extended,
1553  *     - filter_expression
1554  *     - exclusions
1555  *     - padding to align to 64-bits
1556  *     - flattened version of userspace_probe_location
1557  */
1558 static enum lttng_error_code flatten_lttng_events(
1559                 struct lttng_dynamic_pointer_array *events,
1560                 struct lttng_event **flattened_events)
1561 {
1562         enum lttng_error_code ret_code;
1563         int ret, i;
1564         size_t storage_req;
1565         struct lttng_dynamic_buffer local_flattened_events;
1566         int nb_events;
1567
1568         assert(events);
1569         assert(flattened_events);
1570
1571         lttng_dynamic_buffer_init(&local_flattened_events);
1572         nb_events = lttng_dynamic_pointer_array_get_count(events);
1573
1574         ret_code = compute_flattened_size(events, &storage_req);
1575         if (ret_code != LTTNG_OK) {
1576                 goto end;
1577         }
1578
1579         /*
1580          * We must ensure that "local_flattened_events" is never resized so as
1581          * to preserve the validity of the flattened objects.
1582          */
1583         ret = lttng_dynamic_buffer_set_capacity(
1584                         &local_flattened_events, storage_req);
1585         if (ret) {
1586                 ret_code = LTTNG_ERR_NOMEM;
1587                 goto end;
1588         }
1589
1590         /* Start by laying the struct lttng_event */
1591         for (i = 0; i < nb_events; i++) {
1592                 const struct event_list_element *element = (const struct event_list_element *)
1593                                 lttng_dynamic_pointer_array_get_pointer(
1594                                                 events, i);
1595
1596                 if (!element) {
1597                         ret_code = LTTNG_ERR_FATAL;
1598                         goto end;
1599                 }
1600
1601                 ret = lttng_dynamic_buffer_append(&local_flattened_events,
1602                                 element->event, sizeof(struct lttng_event));
1603                 if (ret) {
1604                         ret_code = LTTNG_ERR_NOMEM;
1605                         goto end;
1606                 }
1607         }
1608
1609         for (i = 0; i < nb_events; i++) {
1610                 const struct event_list_element *element = (const struct event_list_element *)
1611                                 lttng_dynamic_pointer_array_get_pointer(events, i);
1612                 struct lttng_event *event = (struct lttng_event *)
1613                         (local_flattened_events.data + (sizeof(struct lttng_event) * i));
1614                 struct lttng_event_extended *event_extended =
1615                         (struct lttng_event_extended *)
1616                                 (local_flattened_events.data + local_flattened_events.size);
1617                 const struct lttng_userspace_probe_location *location = NULL;
1618
1619                 assert(element);
1620
1621                 /* Insert struct lttng_event_extended. */
1622                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1623                                 local_flattened_events.size +
1624                                                 sizeof(*event_extended));
1625                 if (ret) {
1626                         ret_code = LTTNG_ERR_NOMEM;
1627                         goto end;
1628                 }
1629                 event->extended.ptr = event_extended;
1630
1631                 /* Insert filter expression. */
1632                 if (element->filter_expression) {
1633                         const size_t len = strlen(element->filter_expression) + 1;
1634
1635                         event_extended->filter_expression =
1636                                         local_flattened_events.data +
1637                                         local_flattened_events.size;
1638                         ret = lttng_dynamic_buffer_append(
1639                                         &local_flattened_events,
1640                                         element->filter_expression, len);
1641                         if (ret) {
1642                                 ret_code = LTTNG_ERR_NOMEM;
1643                                 goto end;
1644                         }
1645                 }
1646
1647                 /* Insert exclusions. */
1648                 if (element->exclusions) {
1649                         event_extended->exclusions.count =
1650                                         element->exclusions->count;
1651                         event_extended->exclusions.strings =
1652                                         local_flattened_events.data +
1653                                         local_flattened_events.size;
1654
1655                         ret = lttng_dynamic_buffer_append(
1656                                         &local_flattened_events,
1657                                         element->exclusions->names,
1658                                         element->exclusions->count *
1659                                                         LTTNG_SYMBOL_NAME_LEN);
1660                         if (ret) {
1661                                 ret_code = LTTNG_ERR_NOMEM;
1662                                 goto end;
1663                         }
1664                 }
1665
1666                 /* Insert padding to align to 64-bits. */
1667                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1668                                 lttng_align_ceil(local_flattened_events.size,
1669                                                 sizeof(uint64_t)));
1670                 if (ret) {
1671                         ret_code = LTTNG_ERR_NOMEM;
1672                         goto end;
1673                 }
1674
1675                 location = lttng_event_get_userspace_probe_location(
1676                                 element->event);
1677                 if (location) {
1678                         event_extended->probe_location = (struct lttng_userspace_probe_location *)
1679                                         (local_flattened_events.data + local_flattened_events.size);
1680                         ret = lttng_userspace_probe_location_flatten(
1681                                         location, &local_flattened_events);
1682                         if (ret < 0) {
1683                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1684                                 goto end;
1685                         }
1686                 }
1687         }
1688
1689         /* Don't reset local_flattened_events buffer as we return its content. */
1690         *flattened_events = (struct lttng_event *) local_flattened_events.data;
1691         lttng_dynamic_buffer_init(&local_flattened_events);
1692         ret_code = LTTNG_OK;
1693 end:
1694         lttng_dynamic_buffer_reset(&local_flattened_events);
1695         return ret_code;
1696 }
1697
1698 static enum lttng_error_code event_list_create_from_payload(
1699                 struct lttng_payload_view *view,
1700                 unsigned int count,
1701                 struct lttng_dynamic_pointer_array *event_list)
1702 {
1703         enum lttng_error_code ret_code;
1704         int ret;
1705         unsigned int i;
1706         int offset = 0;
1707
1708         assert(view);
1709         assert(event_list);
1710
1711         for (i = 0; i < count; i++) {
1712                 ssize_t event_size;
1713                 struct lttng_payload_view event_view =
1714                                 lttng_payload_view_from_view(view, offset, -1);
1715                 struct event_list_element *element = zmalloc<event_list_element>();
1716
1717                 if (!element) {
1718                         ret_code = LTTNG_ERR_NOMEM;
1719                         goto end;
1720                 }
1721
1722                 /*
1723                  * Lifetime and management of the object is now bound to the
1724                  * array.
1725                  */
1726                 ret = lttng_dynamic_pointer_array_add_pointer(
1727                                 event_list, element);
1728                 if (ret) {
1729                         event_list_destructor(element);
1730                         ret_code = LTTNG_ERR_NOMEM;
1731                         goto end;
1732                 }
1733
1734                 /*
1735                  * Bytecode is not transmitted on listing in any case we do not
1736                  * care about it.
1737                  */
1738                 event_size = lttng_event_create_from_payload(&event_view,
1739                                 &element->event,
1740                                 &element->exclusions,
1741                                 &element->filter_expression, NULL);
1742                 if (event_size < 0) {
1743                         ret_code = LTTNG_ERR_INVALID;
1744                         goto end;
1745                 }
1746
1747                 offset += event_size;
1748         }
1749
1750         if (view->buffer.size != offset) {
1751                 ret_code = LTTNG_ERR_INVALID_PROTOCOL;
1752                 goto end;
1753         }
1754
1755         ret_code = LTTNG_OK;
1756
1757 end:
1758         return ret_code;
1759 }
1760
1761 enum lttng_error_code lttng_events_create_and_flatten_from_payload(
1762                 struct lttng_payload_view *payload,
1763                 unsigned int count,
1764                 struct lttng_event **events)
1765 {
1766         enum lttng_error_code ret = LTTNG_OK;
1767         struct lttng_dynamic_pointer_array local_events;
1768
1769         lttng_dynamic_pointer_array_init(&local_events, event_list_destructor);
1770
1771         /* Deserialize the events. */
1772         {
1773                 struct lttng_payload_view events_view =
1774                                 lttng_payload_view_from_view(payload, 0, -1);
1775
1776                 ret = event_list_create_from_payload(
1777                                 &events_view, count, &local_events);
1778                 if (ret != LTTNG_OK) {
1779                         goto end;
1780                 }
1781         }
1782
1783         ret = flatten_lttng_events(&local_events, events);
1784         if (ret != LTTNG_OK) {
1785                 goto end;
1786         }
1787
1788 end:
1789         lttng_dynamic_pointer_array_reset(&local_events);
1790         return ret;
1791 }
1792
1793 static enum lttng_error_code flatten_lttng_event_fields(
1794                 struct lttng_dynamic_pointer_array *event_fields,
1795                 struct lttng_event_field **flattened_event_fields)
1796 {
1797         int ret, i;
1798         enum lttng_error_code ret_code;
1799         size_t storage_req = 0;
1800         struct lttng_dynamic_buffer local_flattened_event_fields;
1801         int nb_event_field;
1802
1803         assert(event_fields);
1804         assert(flattened_event_fields);
1805
1806         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1807         nb_event_field = lttng_dynamic_pointer_array_get_count(event_fields);
1808
1809         /*
1810          * Here even if the event field contains a `struct lttng_event` that
1811          * could contain dynamic data, in reality it is not the case.
1812          * Dynamic data is not present. Here the flattening is mostly a direct
1813          * memcpy. This is less than ideal but this code is still better than
1814          * direct usage of an unpacked lttng_event_field array.
1815          */
1816         storage_req += sizeof(struct lttng_event_field) * nb_event_field;
1817
1818         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1819
1820         /*
1821          * We must ensure that "local_flattened_event_fields" is never resized
1822          * so as to preserve the validity of the flattened objects.
1823          */
1824         ret = lttng_dynamic_buffer_set_capacity(
1825                         &local_flattened_event_fields, storage_req);
1826         if (ret) {
1827                 ret_code = LTTNG_ERR_NOMEM;
1828                 goto end;
1829         }
1830
1831         for (i = 0; i < nb_event_field; i++) {
1832                 const struct lttng_event_field *element =
1833                                 (const struct lttng_event_field *)
1834                                         lttng_dynamic_pointer_array_get_pointer(
1835                                                 event_fields, i);
1836
1837                 if (!element) {
1838                         ret_code = LTTNG_ERR_FATAL;
1839                         goto end;
1840                 }
1841                 ret = lttng_dynamic_buffer_append(&local_flattened_event_fields,
1842                                 element, sizeof(struct lttng_event_field));
1843                 if (ret) {
1844                         ret_code = LTTNG_ERR_NOMEM;
1845                         goto end;
1846                 }
1847         }
1848
1849         /* Don't reset local_flattened_channels buffer as we return its content. */
1850         *flattened_event_fields = (struct lttng_event_field *) local_flattened_event_fields.data;
1851         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1852         ret_code = LTTNG_OK;
1853 end:
1854         lttng_dynamic_buffer_reset(&local_flattened_event_fields);
1855         return ret_code;
1856 }
1857
1858 static enum lttng_error_code event_field_list_create_from_payload(
1859                 struct lttng_payload_view *view,
1860                 unsigned int count,
1861                 struct lttng_dynamic_pointer_array **event_field_list)
1862 {
1863         enum lttng_error_code ret_code;
1864         int ret, offset = 0;
1865         unsigned int i;
1866         struct lttng_dynamic_pointer_array *list = NULL;
1867
1868         assert(view);
1869         assert(event_field_list);
1870
1871         list = zmalloc<lttng_dynamic_pointer_array>();
1872         if (!list) {
1873                 ret_code = LTTNG_ERR_NOMEM;
1874                 goto end;
1875         }
1876
1877         lttng_dynamic_pointer_array_init(list, free);
1878
1879         for (i = 0; i < count; i++) {
1880                 ssize_t event_field_size;
1881                 struct lttng_event_field *field = NULL;
1882                 struct lttng_payload_view event_field_view =
1883                                 lttng_payload_view_from_view(view, offset, -1);
1884
1885                 event_field_size = lttng_event_field_create_from_payload(
1886                                 &event_field_view, &field);
1887                 if (event_field_size < 0) {
1888                         ret_code = LTTNG_ERR_INVALID;
1889                         goto end;
1890                 }
1891
1892                 /* Lifetime and management of the object is now bound to the array. */
1893                 ret = lttng_dynamic_pointer_array_add_pointer(list, field);
1894                 if (ret) {
1895                         free(field);
1896                         ret_code = LTTNG_ERR_NOMEM;
1897                         goto end;
1898                 }
1899
1900                 offset += event_field_size;
1901         }
1902
1903         if (view->buffer.size != offset) {
1904                 ret_code = LTTNG_ERR_INVALID;
1905                 goto end;
1906         }
1907
1908         *event_field_list = list;
1909         list = NULL;
1910         ret_code = LTTNG_OK;
1911
1912 end:
1913         if (list) {
1914                 lttng_dynamic_pointer_array_reset(list);
1915                 free(list);
1916         }
1917
1918         return ret_code;
1919 }
1920
1921 enum lttng_error_code lttng_event_fields_create_and_flatten_from_payload(
1922                 struct lttng_payload_view *view,
1923                 unsigned int count,
1924                 struct lttng_event_field **fields)
1925 {
1926         enum lttng_error_code ret_code;
1927         struct lttng_dynamic_pointer_array *local_event_fields = NULL;
1928
1929         ret_code = event_field_list_create_from_payload(
1930                         view, count, &local_event_fields);
1931         if (ret_code != LTTNG_OK) {
1932                 goto end;
1933         }
1934
1935         ret_code = flatten_lttng_event_fields(local_event_fields, fields);
1936         if (ret_code != LTTNG_OK) {
1937                 goto end;
1938         }
1939 end:
1940         if (local_event_fields) {
1941                 lttng_dynamic_pointer_array_reset(local_event_fields);
1942                 free(local_event_fields);
1943         }
1944
1945         return ret_code;
1946 }