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 = { 0 };
 117
 118         symbol_name_len = lttng_strnlen(
 119                         function->symbol_name, sizeof(function->symbol_name));
 120         if (symbol_name_len == sizeof(function->symbol_name)) {
 121                 /* Not null-termintated. */
 122                 ret = -1;
 123                 goto end;
 124         }
 125
 126         /* Include the null terminator. */
 127         symbol_name_len += 1;
 128
 129         comm.symbol_name_len = (uint32_t) symbol_name_len;
 130
 131         ret = lttng_dynamic_buffer_append(
 132                         &payload->buffer, &comm, sizeof(comm));
 133         if (ret < 0) {
 134                 ret = -1;
 135                 goto end;
 136         }
 137
 138         ret = lttng_dynamic_buffer_append(&payload->buffer,
 139                         function->symbol_name, symbol_name_len);
 140 end:
 141         return ret;
 142 }
 143
 144 static ssize_t lttng_event_probe_attr_create_from_payload(
 145                 struct lttng_payload_view *view,
 146                 struct lttng_event_probe_attr **probe_attr)
 147 {
 148         ssize_t ret, offset = 0;
 149         const struct lttng_event_probe_attr_comm *comm;
 150         struct lttng_event_probe_attr *local_attr = NULL;
 151         struct lttng_payload_view comm_view = lttng_payload_view_from_view(
 152                         view, offset, sizeof(*comm));
 153
 154         if (!lttng_payload_view_is_valid(&comm_view)) {
 155                 ret = -1;
 156                 goto end;
 157         }
 158
 159         comm = (typeof(comm)) comm_view.buffer.data;
 160         offset += sizeof(*comm);
 161
 162         local_attr = zmalloc<lttng_event_probe_attr>();
 163         if (local_attr == NULL) {
 164                 ret = -1;
 165                 goto end;
 166         }
 167
 168         local_attr->addr = comm->addr;
 169         local_attr->offset = comm->offset;
 170
 171         {
 172                 const char *name;
 173                 struct lttng_payload_view name_view =
 174                                 lttng_payload_view_from_view(view, offset,
 175                                                 comm->symbol_name_len);
 176
 177                 if (!lttng_payload_view_is_valid(&name_view)) {
 178                         ret = -1;
 179                         goto end;
 180                 }
 181
 182                 name = name_view.buffer.data;
 183
 184                 if (!lttng_buffer_view_contains_string(&name_view.buffer, name,
 185                                     comm->symbol_name_len)) {
 186                         ret = -1;
 187                         goto end;
 188                 }
 189
 190                 ret = lttng_strncpy(local_attr->symbol_name, name,
 191                                 sizeof(local_attr->symbol_name));
 192                 if (ret) {
 193                         ret = -1;
 194                         goto end;
 195                 }
 196
 197                 offset += comm->symbol_name_len;
 198         }
 199
 200         *probe_attr = local_attr;
 201         local_attr = NULL;
 202         ret = offset;
 203 end:
 204         free(local_attr);
 205         return ret;
 206 }
 207
 208 static ssize_t lttng_event_function_attr_create_from_payload(
 209                 struct lttng_payload_view *view,
 210                 struct lttng_event_function_attr **function_attr)
 211 {
 212         ssize_t ret, offset = 0;
 213         const struct lttng_event_function_attr_comm *comm;
 214         struct lttng_event_function_attr *local_attr = NULL;
 215         struct lttng_payload_view comm_view = lttng_payload_view_from_view(
 216                         view, offset, sizeof(*comm));
 217
 218         if (!lttng_payload_view_is_valid(&comm_view)) {
 219                 ret = -1;
 220                 goto end;
 221         }
 222
 223         comm = (typeof(comm)) view->buffer.data;
 224         offset += sizeof(*comm);
 225
 226         local_attr = zmalloc<lttng_event_function_attr>();
 227         if (local_attr == NULL) {
 228                 ret = -1;
 229                 goto end;
 230         }
 231
 232         {
 233                 const char *name;
 234                 struct lttng_payload_view name_view =
 235                                 lttng_payload_view_from_view(view, offset,
 236                                                 comm->symbol_name_len);
 237
 238                 if (!lttng_payload_view_is_valid(&name_view)) {
 239                         ret = -1;
 240                         goto end;
 241                 }
 242
 243                 name = name_view.buffer.data;
 244
 245                 if (!lttng_buffer_view_contains_string(&name_view.buffer, name,
 246                                     comm->symbol_name_len)) {
 247                         ret = -1;
 248                         goto end;
 249                 }
 250
 251                 ret = lttng_strncpy(local_attr->symbol_name, name,
 252                                 sizeof(local_attr->symbol_name));
 253                 if (ret) {
 254                         ret = -1;
 255                         goto end;
 256                 }
 257
 258                 offset += comm->symbol_name_len;
 259         }
 260
 261         *function_attr = local_attr;
 262         local_attr = NULL;
 263         ret = offset;
 264 end:
 265         free(local_attr);
 266         return ret;
 267 }
 268
 269 static ssize_t lttng_event_exclusions_create_from_payload(
 270                 struct lttng_payload_view *view,
 271                 uint32_t count,
 272                 struct lttng_event_exclusion **exclusions)
 273 {
 274         ssize_t ret, offset = 0;
 275         const size_t size = (count * LTTNG_SYMBOL_NAME_LEN);
 276         uint32_t i;
 277         const struct lttng_event_exclusion_comm *comm;
 278         struct lttng_event_exclusion *local_exclusions;
 279
 280         local_exclusions = zmalloc<lttng_event_exclusion>(
 281                         sizeof(struct lttng_event_exclusion) + size);
 282         if (!local_exclusions) {
 283                 ret = -1;
 284                 goto end;
 285         }
 286
 287         local_exclusions->count = count;
 288
 289         for (i = 0; i < count; i++) {
 290                 const char *string;
 291                 struct lttng_buffer_view string_view;
 292                 const struct lttng_buffer_view comm_view =
 293                                 lttng_buffer_view_from_view(&view->buffer,
 294                                                 offset, sizeof(*comm));
 295
 296                 if (!lttng_buffer_view_is_valid(&comm_view)) {
 297                         ret = -1;
 298                         goto end;
 299                 }
 300
 301                 comm = (typeof(comm)) comm_view.data;
 302                 offset += sizeof(*comm);
 303
 304                 string_view = lttng_buffer_view_from_view(
 305                                 &view->buffer, offset, comm->len);
 306
 307                 if (!lttng_buffer_view_is_valid(&string_view)) {
 308                         ret = -1;
 309                         goto end;
 310                 }
 311
 312                 string = string_view.data;
 313
 314                 if (!lttng_buffer_view_contains_string(
 315                                     &string_view, string, comm->len)) {
 316                         ret = -1;
 317                         goto end;
 318                 }
 319
 320                 ret = lttng_strncpy(LTTNG_EVENT_EXCLUSION_NAME_AT(local_exclusions, i), string,
 321                                 sizeof(LTTNG_EVENT_EXCLUSION_NAME_AT(local_exclusions, i)));
 322                 if (ret) {
 323                         ret = -1;
 324                         goto end;
 325                 }
 326
 327                 offset += comm->len;
 328         }
 329
 330         *exclusions = local_exclusions;
 331         local_exclusions = NULL;
 332         ret = offset;
 333 end:
 334         free(local_exclusions);
 335         return ret;
 336 }
 337
 338 ssize_t lttng_event_create_from_payload(struct lttng_payload_view *view,
 339                 struct lttng_event **out_event,
 340                 struct lttng_event_exclusion **out_exclusion,
 341                 char **out_filter_expression,
 342                 struct lttng_bytecode **out_bytecode)
 343 {
 344         ssize_t ret, offset = 0;
 345         struct lttng_event *local_event = NULL;
 346         struct lttng_event_exclusion *local_exclusions = NULL;
 347         struct lttng_bytecode *local_bytecode = NULL;
 348         char *local_filter_expression = NULL;
 349         const struct lttng_event_comm *event_comm;
 350         struct lttng_event_function_attr *local_function_attr = NULL;
 351         struct lttng_event_probe_attr *local_probe_attr = NULL;
 352         struct lttng_userspace_probe_location *local_userspace_probe_location =
 353                         NULL;
 354
 355         /*
 356          * Only event is obligatory, the other output argument are optional and
 357          * depends on what the caller is interested in.
 358          */
 359         assert(out_event);
 360         assert(view);
 361
 362         {
 363                 struct lttng_payload_view comm_view =
 364                                 lttng_payload_view_from_view(view, offset,
 365                                                 sizeof(*event_comm));
 366
 367                 if (!lttng_payload_view_is_valid(&comm_view)) {
 368                         ret = -1;
 369                         goto end;
 370                 }
 371
 372                 /* lttng_event_comm header */
 373                 event_comm = (typeof(event_comm)) comm_view.buffer.data;
 374                 offset += sizeof(*event_comm);
 375         }
 376
 377         local_event = lttng_event_create();
 378         if (local_event == NULL) {
 379                 ret = -1;
 380                 goto end;
 381         }
 382
 383         local_event->type = (enum lttng_event_type) event_comm->event_type;
 384         local_event->loglevel_type = (enum lttng_loglevel_type) event_comm->loglevel_type;
 385         local_event->loglevel = event_comm->loglevel;
 386         local_event->enabled = event_comm->enabled;
 387         local_event->pid = event_comm->pid;
 388         local_event->flags = (enum lttng_event_flag) event_comm->flags;
 389
 390         {
 391                 const char *name;
 392                 const struct lttng_buffer_view name_view =
 393                                 lttng_buffer_view_from_view(&view->buffer,
 394                                                 offset, event_comm->name_len);
 395
 396                 if (!lttng_buffer_view_is_valid(&name_view)) {
 397                         ret = -1;
 398                         goto end;
 399                 }
 400
 401                 name = (const char *) name_view.data;
 402
 403                 if (!lttng_buffer_view_contains_string(
 404                                     &name_view, name, event_comm->name_len)) {
 405                         ret = -1;
 406                         goto end;
 407                 }
 408
 409                 ret = lttng_strncpy(local_event->name, name,
 410                                 sizeof(local_event->name));
 411                 if (ret) {
 412                         ret = -1;
 413                         goto end;
 414                 }
 415
 416                 offset += event_comm->name_len;
 417         }
 418
 419         /* Exclusions */
 420         if (event_comm->exclusion_count == 0) {
 421                 goto deserialize_filter_expression;
 422         }
 423
 424         {
 425                 struct lttng_payload_view exclusions_view =
 426                                 lttng_payload_view_from_view(
 427                                                 view, offset, -1);
 428
 429                 if (!lttng_payload_view_is_valid(&exclusions_view)) {
 430                         ret = -1;
 431                         goto end;
 432                 }
 433
 434                 ret = lttng_event_exclusions_create_from_payload(&exclusions_view,
 435                                 event_comm->exclusion_count, &local_exclusions);
 436                 if (ret < 0) {
 437                         ret = -1;
 438                         goto end;
 439                 }
 440                 offset += ret;
 441
 442                 local_event->exclusion = 1;
 443         }
 444
 445 deserialize_filter_expression:
 446
 447         if (event_comm->filter_expression_len == 0) {
 448                 if (event_comm->bytecode_len != 0) {
 449                         /*
 450                          * This is an invalid event payload.
 451                          *
 452                          * Filter expression without bytecode is possible but
 453                          * not the other way around.
 454                          * */
 455                         ret = -1;
 456                         goto end;
 457                 }
 458                 goto deserialize_event_type_payload;
 459         }
 460
 461         {
 462                 const char *filter_expression_buffer;
 463                 struct lttng_buffer_view filter_expression_view =
 464                                 lttng_buffer_view_from_view(&view->buffer, offset,
 465                                                 event_comm->filter_expression_len);
 466
 467                 if (!lttng_buffer_view_is_valid(&filter_expression_view)) {
 468                         ret = -1;
 469                         goto end;
 470                 }
 471
 472                 filter_expression_buffer = filter_expression_view.data;
 473
 474                 if (!lttng_buffer_view_contains_string(&filter_expression_view,
 475                                     filter_expression_buffer,
 476                                     event_comm->filter_expression_len)) {
 477                         ret = -1;
 478                         goto end;
 479                 }
 480
 481                 local_filter_expression = lttng_strndup(
 482                                 filter_expression_buffer,
 483                                 event_comm->filter_expression_len);
 484                 if (!local_filter_expression) {
 485                         ret = -1;
 486                         goto end;
 487                 }
 488
 489                 local_event->filter = 1;
 490
 491                 offset += event_comm->filter_expression_len;
 492         }
 493
 494         if (event_comm->bytecode_len == 0) {
 495                 /*
 496                  * Filter expression can be present but without bytecode
 497                  * when dealing with event listing.
 498                  */
 499                 goto deserialize_event_type_payload;
 500         }
 501
 502         /* Bytecode */
 503         {
 504                 struct lttng_payload_view bytecode_view =
 505                                 lttng_payload_view_from_view(view, offset,
 506                                                 event_comm->bytecode_len);
 507
 508                 if (!lttng_payload_view_is_valid(&bytecode_view)) {
 509                         ret = -1;
 510                         goto end;
 511                 }
 512
 513                 local_bytecode = zmalloc<lttng_bytecode>(event_comm->bytecode_len);
 514                 if (!local_bytecode) {
 515                         ret = -1;
 516                         goto end;
 517                 }
 518
 519                 memcpy(local_bytecode, bytecode_view.buffer.data,
 520                                 event_comm->bytecode_len);
 521                 if ((local_bytecode->len + sizeof(*local_bytecode)) !=
 522                                 event_comm->bytecode_len) {
 523                         ret = -1;
 524                         goto end;
 525                 }
 526
 527                 offset += event_comm->bytecode_len;
 528         }
 529
 530 deserialize_event_type_payload:
 531         /* Event type specific payload */
 532         switch (local_event->type) {
 533         case LTTNG_EVENT_FUNCTION:
 534                 /* Fallthrough */
 535         case LTTNG_EVENT_PROBE:
 536         {
 537                 struct lttng_payload_view probe_attr_view =
 538                                 lttng_payload_view_from_view(view, offset,
 539                                                 event_comm->lttng_event_probe_attr_len);
 540
 541                 if (event_comm->lttng_event_probe_attr_len == 0) {
 542                         ret = -1;
 543                         goto end;
 544                 }
 545
 546                 if (!lttng_payload_view_is_valid(&probe_attr_view)) {
 547                         ret = -1;
 548                         goto end;
 549                 }
 550
 551                 ret = lttng_event_probe_attr_create_from_payload(
 552                                 &probe_attr_view, &local_probe_attr);
 553                 if (ret < 0 || ret != event_comm->lttng_event_probe_attr_len) {
 554                         ret = -1;
 555                         goto end;
 556                 }
 557
 558                 /* Copy to the local event. */
 559                 memcpy(&local_event->attr.probe, local_probe_attr,
 560                                 sizeof(local_event->attr.probe));
 561
 562                 offset += ret;
 563                 break;
 564         }
 565         case LTTNG_EVENT_FUNCTION_ENTRY:
 566         {
 567                 struct lttng_payload_view function_attr_view =
 568                                 lttng_payload_view_from_view(view, offset,
 569                                                 event_comm->lttng_event_function_attr_len);
 570
 571                 if (event_comm->lttng_event_function_attr_len == 0) {
 572                         ret = -1;
 573                         goto end;
 574                 }
 575
 576                 if (!lttng_payload_view_is_valid(&function_attr_view)) {
 577                         ret = -1;
 578                         goto end;
 579                 }
 580
 581                 ret = lttng_event_function_attr_create_from_payload(
 582                                 &function_attr_view, &local_function_attr);
 583                 if (ret < 0 || ret != event_comm->lttng_event_function_attr_len) {
 584                         ret = -1;
 585                         goto end;
 586                 }
 587
 588                 /* Copy to the local event. */
 589                 memcpy(&local_event->attr.ftrace, local_function_attr,
 590                                 sizeof(local_event->attr.ftrace));
 591
 592                 offset += ret;
 593
 594                 break;
 595         }
 596         case LTTNG_EVENT_USERSPACE_PROBE:
 597         {
 598                 struct lttng_payload_view userspace_probe_location_view =
 599                                 lttng_payload_view_from_view(view, offset,
 600                                                 event_comm->userspace_probe_location_len);
 601
 602                 if (event_comm->userspace_probe_location_len == 0) {
 603                         ret = -1;
 604                         goto end;
 605                 }
 606
 607                 if (!lttng_payload_view_is_valid(
 608                                     &userspace_probe_location_view)) {
 609                         ret = -1;
 610                         goto end;
 611                 }
 612
 613                 ret = lttng_userspace_probe_location_create_from_payload(
 614                                 &userspace_probe_location_view,
 615                                 &local_userspace_probe_location);
 616                 if (ret < 0) {
 617                         WARN("Failed to create a userspace probe location from the received buffer");
 618                         ret = -1;
 619                         goto end;
 620                 }
 621
 622                 if (ret != event_comm->userspace_probe_location_len) {
 623                         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);
 624                         ret = -1;
 625                         goto end;
 626                 }
 627
 628                 /* Attach the probe location to the event. */
 629                 ret = lttng_event_set_userspace_probe_location(
 630                                 local_event, local_userspace_probe_location);
 631                 if (ret) {
 632                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 633                         goto end;
 634                 }
 635
 636                 /*
 637                  * Userspace probe location object ownership transfered to the
 638                  * event object.
 639                  */
 640                 local_userspace_probe_location = NULL;
 641                 offset += event_comm->userspace_probe_location_len;
 642                 break;
 643         }
 644         case LTTNG_EVENT_TRACEPOINT:
 645                 /* Fallthrough */
 646         case LTTNG_EVENT_ALL:
 647                 /* Fallthrough */
 648         case LTTNG_EVENT_SYSCALL:
 649                 /* Fallthrough */
 650         case LTTNG_EVENT_NOOP:
 651                 /* Nothing to do here */
 652                 break;
 653         default:
 654                 ret = LTTNG_ERR_UND;
 655                 goto end;
 656                 break;
 657         }
 658
 659         /* Transfer ownership to the caller. */
 660         *out_event = local_event;
 661         local_event = NULL;
 662
 663         if (out_bytecode) {
 664                 *out_bytecode = local_bytecode;
 665                 local_bytecode = NULL;
 666         }
 667
 668         if (out_exclusion) {
 669                 *out_exclusion = local_exclusions;
 670                 local_exclusions = NULL;
 671         }
 672
 673         if (out_filter_expression) {
 674                 *out_filter_expression = local_filter_expression;
 675                 local_filter_expression = NULL;
 676         }
 677
 678         ret = offset;
 679 end:
 680         lttng_event_destroy(local_event);
 681         lttng_userspace_probe_location_destroy(local_userspace_probe_location);
 682         free(local_filter_expression);
 683         free(local_exclusions);
 684         free(local_bytecode);
 685         free(local_function_attr);
 686         free(local_probe_attr);
 687         return ret;
 688 }
 689
 690 int lttng_event_serialize(const struct lttng_event *event,
 691                 unsigned int exclusion_count,
 692                 char **exclusion_list,
 693                 char *filter_expression,
 694                 size_t bytecode_len,
 695                 struct lttng_bytecode *bytecode,
 696                 struct lttng_payload *payload)
 697 {
 698         int ret;
 699         unsigned int i;
 700         size_t header_offset, size_before_payload;
 701         size_t name_len;
 702         struct lttng_event_comm event_comm = {};
 703         struct lttng_event_comm *header;
 704
 705         assert(event);
 706         assert(payload);
 707         assert(exclusion_count == 0 || exclusion_list);
 708
 709         /* Save the header location for later in-place header update. */
 710         header_offset = payload->buffer.size;
 711
 712         name_len = lttng_strnlen(event->name, sizeof(event->name));
 713         if (name_len == sizeof(event->name)) {
 714                 /* Event name is not NULL-terminated. */
 715                 ret = -1;
 716                 goto end;
 717         }
 718
 719         /* Add null termination. */
 720         name_len += 1;
 721
 722         if (exclusion_count > UINT32_MAX) {
 723                 /* Possible overflow. */
 724                 ret = -1;
 725                 goto end;
 726         }
 727
 728         if (bytecode_len > UINT32_MAX) {
 729                 /* Possible overflow. */
 730                 ret = -1;
 731                 goto end;
 732         }
 733
 734         event_comm.name_len = (uint32_t) name_len;
 735         event_comm.event_type = (int8_t) event->type;
 736         event_comm.loglevel_type = (int8_t) event->loglevel_type;
 737         event_comm.loglevel = (int32_t) event->loglevel;
 738         event_comm.enabled = (int8_t) event->enabled;
 739         event_comm.pid = (int32_t) event->pid;
 740         event_comm.exclusion_count = (uint32_t) exclusion_count;
 741         event_comm.bytecode_len = (uint32_t) bytecode_len;
 742         event_comm.flags = (int32_t) event->flags;
 743
 744         if (filter_expression) {
 745                 event_comm.filter_expression_len =
 746                                 strlen(filter_expression) + 1;
 747         }
 748
 749         /* Header */
 750         ret = lttng_dynamic_buffer_append(
 751                         &payload->buffer, &event_comm, sizeof(event_comm));
 752         if (ret) {
 753                 goto end;
 754         }
 755
 756         /* Event name */
 757         ret = lttng_dynamic_buffer_append(
 758                         &payload->buffer, event->name, name_len);
 759         if (ret) {
 760                 goto end;
 761         }
 762
 763         /* Exclusions */
 764         for (i = 0; i < exclusion_count; i++) {
 765                 const size_t exclusion_len = lttng_strnlen(
 766                                 *(exclusion_list + i), LTTNG_SYMBOL_NAME_LEN);
 767                 const struct lttng_event_exclusion_comm exclusion_header = {
 768                         .len = (uint32_t) exclusion_len + 1,
 769                 };
 770
 771                 if (exclusion_len == LTTNG_SYMBOL_NAME_LEN) {
 772                         /* Exclusion is not NULL-terminated. */
 773                         ret = -1;
 774                         goto end;
 775                 }
 776
 777                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 778                                 &exclusion_header, sizeof(exclusion_header));
 779                 if (ret) {
 780                         goto end;
 781                 }
 782
 783                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 784                                 *(exclusion_list + i), exclusion_len + 1);
 785                 if (ret) {
 786                         goto end;
 787                 }
 788         }
 789
 790         /* Filter expression and its bytecode */
 791         if (filter_expression) {
 792                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 793                                 filter_expression,
 794                                 event_comm.filter_expression_len);
 795                 if (ret) {
 796                         goto end;
 797                 }
 798
 799                 /*
 800                  * Bytecode can be absent when we serialize to the client
 801                  * for listing.
 802                  */
 803                 if (bytecode) {
 804                         ret = lttng_dynamic_buffer_append(&payload->buffer,
 805                                         bytecode, bytecode_len);
 806                         if (ret) {
 807                                 goto end;
 808                         }
 809                 }
 810         }
 811
 812         size_before_payload = payload->buffer.size;
 813
 814         /* Event type specific payload */
 815         switch (event->type) {
 816         case LTTNG_EVENT_FUNCTION:
 817                 /* Fallthrough */
 818         case LTTNG_EVENT_PROBE:
 819                 ret = lttng_event_probe_attr_serialize(&event->attr.probe, payload);
 820                 if (ret) {
 821                         ret = -1;
 822                         goto end;
 823                 }
 824
 825                 header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 826                                                       header_offset);
 827                 header->lttng_event_probe_attr_len =
 828                                 payload->buffer.size - size_before_payload;
 829
 830                 break;
 831         case LTTNG_EVENT_FUNCTION_ENTRY:
 832                 ret = lttng_event_function_attr_serialize(
 833                                 &event->attr.ftrace, payload);
 834                 if (ret) {
 835                         ret = -1;
 836                         goto end;
 837                 }
 838
 839                 /* Update the lttng_event_function_attr len. */
 840                 header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 841                                                       header_offset);
 842                 header->lttng_event_function_attr_len =
 843                                 payload->buffer.size - size_before_payload;
 844
 845                 break;
 846         case LTTNG_EVENT_USERSPACE_PROBE:
 847         {
 848                 const struct lttng_event_extended *ev_ext =
 849                                 (const struct lttng_event_extended *)
 850                                                 event->extended.ptr;
 851
 852                 assert(event->extended.ptr);
 853                 assert(ev_ext->probe_location);
 854
 855                 size_before_payload = payload->buffer.size;
 856                 if (ev_ext->probe_location) {
 857                         /*
 858                          * lttng_userspace_probe_location_serialize returns the
 859                          * number of bytes that were appended to the buffer.
 860                          */
 861                         ret = lttng_userspace_probe_location_serialize(
 862                                         ev_ext->probe_location, payload);
 863                         if (ret < 0) {
 864                                 goto end;
 865                         }
 866
 867                         ret = 0;
 868
 869                         /* Update the userspace probe location len. */
 870                         header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 871                                                               header_offset);
 872                         header->userspace_probe_location_len =
 873                                         payload->buffer.size - size_before_payload;
 874                 }
 875                 break;
 876         }
 877         case LTTNG_EVENT_TRACEPOINT:
 878                 /* Fallthrough */
 879         case LTTNG_EVENT_ALL:
 880                 /* Fallthrough */
 881         default:
 882                 /* Nothing to do here. */
 883                 break;
 884         }
 885
 886 end:
 887         return ret;
 888 }
 889
 890 static ssize_t lttng_event_context_app_populate_from_payload(
 891                 const struct lttng_payload_view *view,
 892                 struct lttng_event_context *event_ctx)
 893 {
 894         ssize_t ret, offset = 0;
 895         const struct lttng_event_context_app_comm *comm;
 896         char *provider_name = NULL, *context_name = NULL;
 897         size_t provider_name_len, context_name_len;
 898         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
 899                         &view->buffer, offset, sizeof(*comm));
 900
 901         assert(event_ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
 902
 903         if (!lttng_buffer_view_is_valid(&comm_view)) {
 904                 ret = -1;
 905                 goto end;
 906         }
 907
 908         comm = (typeof(comm)) comm_view.data;
 909         offset += sizeof(*comm);
 910
 911         provider_name_len = comm->provider_name_len;
 912         context_name_len = comm->ctx_name_len;
 913
 914         if (provider_name_len == 0 || context_name_len == 0) {
 915                 /*
 916                  * Application provider and context names MUST
 917                  * be provided.
 918                  */
 919                 ret = -1;
 920                 goto end;
 921         }
 922
 923         {
 924                 const char *name;
 925                 const struct lttng_buffer_view provider_name_view =
 926                                 lttng_buffer_view_from_view(&view->buffer,
 927                                                 offset,
 928                                                 provider_name_len);
 929
 930                 if (!lttng_buffer_view_is_valid(&provider_name_view)) {
 931                         ret = -1;
 932                         goto end;
 933                 }
 934
 935                 name = provider_name_view.data;
 936
 937                 if (!lttng_buffer_view_contains_string(&provider_name_view,
 938                                 name, provider_name_len)) {
 939                         ret = -1;
 940                         goto end;
 941                 }
 942
 943                 provider_name = lttng_strndup(name, provider_name_len);
 944                 if (!provider_name) {
 945                         ret = -1;
 946                         goto end;
 947                 }
 948
 949                 offset += provider_name_len;
 950         }
 951
 952         {
 953                 const char *name;
 954                 const struct lttng_buffer_view context_name_view =
 955                                 lttng_buffer_view_from_view(
 956                                                 &view->buffer, offset,
 957                                                 context_name_len);
 958
 959                 if (!lttng_buffer_view_is_valid(&context_name_view)) {
 960                         ret = -1;
 961                         goto end;
 962                 }
 963
 964                 name = context_name_view.data;
 965
 966                 if (!lttng_buffer_view_contains_string(&context_name_view, name,
 967                                     context_name_len)) {
 968                         ret = -1;
 969                         goto end;
 970                 }
 971
 972                 context_name = lttng_strndup(name, context_name_len);
 973                 if (!context_name) {
 974                         ret = -1;
 975                         goto end;
 976                 }
 977
 978                 offset += context_name_len;
 979         }
 980
 981         /* Transfer ownership of the strings */
 982         event_ctx->u.app_ctx.provider_name = provider_name;
 983         event_ctx->u.app_ctx.ctx_name = context_name;
 984         provider_name = NULL;
 985         context_name = NULL;
 986
 987         ret = offset;
 988 end:
 989         free(provider_name);
 990         free(context_name);
 991
 992         return ret;
 993 }
 994
 995 static ssize_t lttng_event_context_perf_counter_populate_from_payload(
 996                 const struct lttng_payload_view *view,
 997                 struct lttng_event_context *event_ctx)
 998 {
 999         int ret;
1000         ssize_t consumed, offset = 0;
1001         const struct lttng_event_context_perf_counter_comm *comm;
1002         size_t name_len;
1003         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
1004                         &view->buffer, offset, sizeof(*comm));
1005
1006         assert(event_ctx->ctx == LTTNG_EVENT_CONTEXT_PERF_COUNTER ||
1007                         event_ctx->ctx ==
1008                                         LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER ||
1009                         event_ctx->ctx == LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER);
1010
1011         if (!lttng_buffer_view_is_valid(&comm_view)) {
1012                 consumed = -1;
1013                 goto end;
1014         }
1015
1016         comm = (typeof(comm)) comm_view.data;
1017         offset += sizeof(*comm);
1018
1019         name_len = comm->name_len;
1020
1021         {
1022                 const char *name;
1023                 const struct lttng_buffer_view provider_name_view =
1024                                 lttng_buffer_view_from_view(
1025                                                 &view->buffer, offset,
1026                                                 name_len);
1027
1028                 if (!lttng_buffer_view_is_valid(&provider_name_view)) {
1029                         consumed = -1;
1030                         goto end;
1031                 }
1032
1033                 name = provider_name_view.data;
1034
1035                 if (!lttng_buffer_view_contains_string(
1036                                     &provider_name_view, name, name_len)) {
1037                         consumed = -1;
1038                         goto end;
1039                 }
1040
1041                 ret = lttng_strncpy(event_ctx->u.perf_counter.name, name,
1042                                 sizeof(event_ctx->u.perf_counter.name));
1043                 if (ret) {
1044                         consumed = -1;
1045                         goto end;
1046                 }
1047                 offset += name_len;
1048         }
1049
1050         event_ctx->u.perf_counter.config = comm->config;
1051         event_ctx->u.perf_counter.type = comm->type;
1052
1053         consumed = offset;
1054
1055 end:
1056         return consumed;
1057 }
1058
1059 ssize_t lttng_event_context_create_from_payload(
1060                 struct lttng_payload_view *view,
1061                 struct lttng_event_context **event_ctx)
1062 {
1063         ssize_t ret, offset = 0;
1064         const struct lttng_event_context_comm *comm;
1065         struct lttng_event_context *local_context = NULL;
1066         struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
1067                         &view->buffer, offset, sizeof(*comm));
1068
1069         assert(event_ctx);
1070         assert(view);
1071
1072         if (!lttng_buffer_view_is_valid(&comm_view)) {
1073                 ret = -1;
1074                 goto end;
1075         }
1076
1077         comm = (typeof(comm)) comm_view.data;
1078         offset += sizeof(*comm);
1079
1080         local_context = zmalloc<lttng_event_context>();
1081         if (!local_context) {
1082                 ret = -1;
1083                 goto end;
1084         }
1085
1086         local_context->ctx = (lttng_event_context_type) comm->type;
1087
1088         {
1089                 struct lttng_payload_view subtype_view =
1090                                 lttng_payload_view_from_view(view, offset, -1);
1091
1092                 switch (local_context->ctx) {
1093                 case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1094                         ret = lttng_event_context_app_populate_from_payload(
1095                                         &subtype_view, local_context);
1096                         break;
1097                 case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1098                 case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1099                 case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1100                         ret = lttng_event_context_perf_counter_populate_from_payload(
1101                                         &subtype_view, local_context);
1102                         break;
1103                 default:
1104                         /* Nothing else to deserialize. */
1105                         ret = 0;
1106                         break;
1107                 }
1108         }
1109
1110         if (ret < 0) {
1111                 goto end;
1112         }
1113
1114         offset += ret;
1115
1116         *event_ctx = local_context;
1117         local_context = NULL;
1118         ret = offset;
1119
1120 end:
1121         free(local_context);
1122         return ret;
1123 }
1124
1125 static int lttng_event_context_app_serialize(
1126                 struct lttng_event_context *context,
1127                 struct lttng_payload *payload)
1128 {
1129         int ret;
1130         struct lttng_event_context_app_comm comm = {};
1131         size_t provider_len, ctx_len;
1132         const char *provider_name;
1133         const char *ctx_name;
1134
1135         assert(payload);
1136         assert(context);
1137         assert(context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
1138
1139         provider_name = context->u.app_ctx.provider_name;
1140         ctx_name = context->u.app_ctx.ctx_name;
1141
1142         if (!provider_name || !ctx_name) {
1143                 ret = -LTTNG_ERR_INVALID;
1144                 goto end;
1145         }
1146
1147         provider_len = strlen(provider_name);
1148         if (provider_len == 0) {
1149                 ret = -LTTNG_ERR_INVALID;
1150                 goto end;
1151         }
1152
1153         /* Include the null terminator. */
1154         provider_len += 1;
1155         comm.provider_name_len = provider_len;
1156
1157         ctx_len = strlen(ctx_name);
1158         if (ctx_len == 0) {
1159                 ret = -LTTNG_ERR_INVALID;
1160                 goto end;
1161         }
1162
1163         /* Include the null terminator. */
1164         ctx_len += 1;
1165         comm.ctx_name_len = ctx_len;
1166
1167         /* Header */
1168         ret = lttng_dynamic_buffer_append(&payload->buffer, &comm,
1169                         sizeof(comm));
1170         if (ret) {
1171                 ret = -1;
1172                 goto end;
1173         }
1174
1175         ret = lttng_dynamic_buffer_append(&payload->buffer, provider_name,
1176                         provider_len);
1177         if (ret) {
1178                 ret = -1;
1179                 goto end;
1180         }
1181
1182         ret = lttng_dynamic_buffer_append(&payload->buffer, ctx_name,
1183                         ctx_len);
1184         if (ret) {
1185                 ret = -1;
1186                 goto end;
1187         }
1188
1189 end:
1190         return ret;
1191 }
1192
1193 static int lttng_event_context_perf_counter_serialize(
1194                 struct lttng_event_perf_counter_ctx *context,
1195                 struct lttng_payload *payload)
1196 {
1197         int ret;
1198         struct lttng_event_context_perf_counter_comm comm = {};
1199
1200         assert(payload);
1201         assert(context);
1202
1203         comm.config = context->config;
1204         comm.type = context->type;
1205         comm.name_len = lttng_strnlen(context->name, sizeof(context->name));
1206
1207         if (comm.name_len == sizeof(context->name)) {
1208                 ret = -1;
1209                 goto end;
1210         }
1211
1212         /* Include the null terminator. */
1213         comm.name_len += 1;
1214
1215         /* Header */
1216         ret = lttng_dynamic_buffer_append(&payload->buffer, &comm,
1217                         sizeof(comm));
1218         if (ret) {
1219                 ret = -1;
1220                 goto end;
1221         }
1222
1223         ret = lttng_dynamic_buffer_append(&payload->buffer, context->name,
1224                         comm.name_len);
1225         if (ret) {
1226                 ret = -1;
1227                 goto end;
1228         }
1229
1230 end:
1231         return ret;
1232 }
1233
1234 int lttng_event_context_serialize(struct lttng_event_context *context,
1235                 struct lttng_payload *payload)
1236 {
1237         int ret;
1238         struct lttng_event_context_comm context_comm = { 0 };
1239
1240         assert(context);
1241         assert(payload);
1242
1243         context_comm.type = (uint32_t) context->ctx;
1244
1245         /* Header */
1246         ret = lttng_dynamic_buffer_append(
1247                         &payload->buffer, &context_comm, sizeof(context_comm));
1248         if (ret) {
1249                 goto end;
1250         }
1251
1252         switch (context->ctx) {
1253         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1254                 ret = lttng_event_context_app_serialize(context, payload);
1255                 break;
1256         case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1257         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1258         case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1259                 ret = lttng_event_context_perf_counter_serialize(
1260                                 &context->u.perf_counter, payload);
1261                 break;
1262         default:
1263                 /* Nothing else to serialize. */
1264                 break;
1265         }
1266
1267         if (ret) {
1268                 goto end;
1269         }
1270
1271 end:
1272         return ret;
1273 }
1274
1275 void lttng_event_context_destroy(struct lttng_event_context *context)
1276 {
1277         if (!context) {
1278                 return;
1279         }
1280
1281         if (context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
1282                 free(context->u.app_ctx.provider_name);
1283                 free(context->u.app_ctx.ctx_name);
1284         }
1285
1286         free(context);
1287 }
1288
1289 /*
1290  * This is a specialized populate for lttng_event_field since it ignores
1291  * the extension field of the lttng_event struct and simply copies what it can
1292  * to the internal struct lttng_event of a lttng_event_field.
1293  */
1294 static void lttng_event_field_populate_lttng_event_from_event(
1295                 const struct lttng_event *src, struct lttng_event *destination)
1296 {
1297         memcpy(destination, src, sizeof(*destination));
1298
1299         /* Remove all possible dynamic data from the destination event rule. */
1300         destination->extended.ptr = NULL;
1301 }
1302
1303 ssize_t lttng_event_field_create_from_payload(
1304                 struct lttng_payload_view *view,
1305                 struct lttng_event_field **field)
1306 {
1307         ssize_t ret, offset = 0;
1308         struct lttng_event_field *local_event_field = NULL;
1309         struct lttng_event *event = NULL;
1310         const struct lttng_event_field_comm *comm;
1311         const char* name = NULL;
1312
1313         assert(field);
1314         assert(view);
1315
1316         {
1317                 const struct lttng_buffer_view comm_view =
1318                                 lttng_buffer_view_from_view(
1319                                                 &view->buffer, offset,
1320                                                 sizeof(*comm));
1321
1322                 if (!lttng_buffer_view_is_valid(&comm_view)) {
1323                         ret = -1;
1324                         goto end;
1325                 }
1326
1327                 /* lttng_event_field_comm header */
1328                 comm = (const lttng_event_field_comm *) comm_view.data;
1329                 offset += sizeof(*comm);
1330         }
1331
1332         local_event_field = zmalloc<lttng_event_field>();
1333         if (!local_event_field) {
1334                 ret = -1;
1335                 goto end;
1336         }
1337
1338         local_event_field->type = (lttng_event_field_type) comm->type;
1339         local_event_field->nowrite = comm->nowrite;
1340
1341         /* Field name */
1342         {
1343                 const struct lttng_buffer_view name_view =
1344                                 lttng_buffer_view_from_view(
1345                                                 &view->buffer, offset,
1346                                                 comm->name_len);
1347
1348                 if (!lttng_buffer_view_is_valid(&name_view)) {
1349                         ret = -1;
1350                         goto end;
1351                 }
1352
1353                 name = name_view.data;
1354
1355                 if (!lttng_buffer_view_contains_string(&name_view,
1356                                 name_view.data, comm->name_len)) {
1357                         ret = -1;
1358                         goto end;
1359                 }
1360
1361                 if (comm->name_len > LTTNG_SYMBOL_NAME_LEN - 1) {
1362                         /* Name is too long.*/
1363                         ret = -1;
1364                         goto end;
1365                 }
1366
1367                 offset += comm->name_len;
1368         }
1369
1370         /* Event */
1371         {
1372                 struct lttng_payload_view event_view =
1373                                 lttng_payload_view_from_view(
1374                                                 view, offset,
1375                                                 comm->event_len);
1376
1377                 if (!lttng_payload_view_is_valid(&event_view)) {
1378                         ret = -1;
1379                         goto end;
1380                 }
1381
1382                 ret = lttng_event_create_from_payload(&event_view, &event, NULL,
1383                                 NULL, NULL);
1384                 if (ret != comm->event_len) {
1385                         ret = -1;
1386                         goto end;
1387                 }
1388
1389                 offset += ret;
1390         }
1391
1392         assert(name);
1393         assert(event);
1394
1395         if (lttng_strncpy(local_event_field->field_name, name,
1396                         sizeof(local_event_field->field_name))) {
1397                 ret = -1;
1398                 goto end;
1399         }
1400
1401         lttng_event_field_populate_lttng_event_from_event(
1402                         event, &local_event_field->event);
1403
1404         *field = local_event_field;
1405         local_event_field = NULL;
1406         ret = offset;
1407 end:
1408         lttng_event_destroy(event);
1409         free(local_event_field);
1410         return ret;
1411 }
1412
1413 int lttng_event_field_serialize(const struct lttng_event_field *field,
1414                 struct lttng_payload *payload)
1415 {
1416         int ret;
1417         size_t header_offset, size_before_event;
1418         size_t name_len;
1419         struct lttng_event_field_comm event_field_comm = {};
1420         struct lttng_event_field_comm *header;
1421
1422         assert(field);
1423         assert(payload);
1424
1425         /* Save the header location for later in-place header update. */
1426         header_offset = payload->buffer.size;
1427
1428         name_len = strnlen(field->field_name, sizeof(field->field_name));
1429         if (name_len == sizeof(field->field_name)) {
1430                 /* Event name is not NULL-terminated. */
1431                 ret = -1;
1432                 goto end;
1433         }
1434
1435         /* Add null termination. */
1436         name_len += 1;
1437
1438         event_field_comm.type = field->type;
1439         event_field_comm.nowrite = (uint8_t)field->nowrite;
1440         event_field_comm.name_len = name_len;
1441
1442         /* Header */
1443         ret = lttng_dynamic_buffer_append(
1444                         &payload->buffer, &event_field_comm,
1445                         sizeof(event_field_comm));
1446         if (ret) {
1447                 goto end;
1448         }
1449
1450         /* Field name */
1451         ret = lttng_dynamic_buffer_append(&payload->buffer, field->field_name,
1452                         name_len);
1453         if (ret) {
1454                 goto end;
1455         }
1456
1457         size_before_event = payload->buffer.size;
1458         ret = lttng_event_serialize(
1459                         &field->event, 0, NULL, NULL, 0, 0, payload);
1460         if (ret) {
1461                 ret = -1;
1462                 goto end;
1463         }
1464
1465         /* Update the event len. */
1466         header = (struct lttng_event_field_comm *)
1467                         ((char *) payload->buffer.data +
1468                                 header_offset);
1469         header->event_len = payload->buffer.size - size_before_event;
1470
1471 end:
1472         return ret;
1473 }
1474
1475 static enum lttng_error_code compute_flattened_size(
1476                 struct lttng_dynamic_pointer_array *events, size_t *size)
1477 {
1478         enum lttng_error_code ret_code;
1479         int ret = 0;
1480         size_t storage_req, event_count, i;
1481
1482         assert(size);
1483         assert(events);
1484
1485         event_count = lttng_dynamic_pointer_array_get_count(events);
1486
1487         /* The basic struct lttng_event */
1488         storage_req = event_count * sizeof(struct lttng_event);
1489
1490         /* The struct·lttng_event_extended */
1491         storage_req += event_count * sizeof(struct lttng_event_extended);
1492
1493         for (i = 0; i < event_count; i++) {
1494                 int probe_storage_req = 0;
1495                 const struct event_list_element *element = (const struct event_list_element *)
1496                                 lttng_dynamic_pointer_array_get_pointer(
1497                                                 events, i);
1498                 const struct lttng_userspace_probe_location *location = NULL;
1499
1500                 location = lttng_event_get_userspace_probe_location(
1501                                 element->event);
1502                 if (location) {
1503                         ret = lttng_userspace_probe_location_flatten(
1504                                         location, NULL);
1505                         if (ret < 0) {
1506                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1507                                 goto end;
1508                         }
1509
1510                         probe_storage_req = ret;
1511                 }
1512
1513                 if (element->filter_expression) {
1514                         storage_req += strlen(element->filter_expression) + 1;
1515                 }
1516
1517                 if (element->exclusions) {
1518                         storage_req += element->exclusions->count *
1519                                 LTTNG_SYMBOL_NAME_LEN;
1520                 }
1521
1522                 /* Padding to ensure the flat probe is aligned. */
1523                 storage_req = lttng_align_ceil(storage_req, sizeof(uint64_t));
1524                 storage_req += probe_storage_req;
1525         }
1526
1527         *size = storage_req;
1528         ret_code = LTTNG_OK;
1529
1530 end:
1531         return ret_code;
1532 }
1533
1534 /*
1535  * Flatten a list of struct lttng_event.
1536  *
1537  * The buffer that is returned to the API client  must contain a "flat" version
1538  * of the events that are returned. In other words, all pointers within an
1539  * lttng_event must point to a location within the returned buffer so that the
1540  * user may free everything by simply calling free() on the returned buffer.
1541  * This is needed in order to maintain API compatibility.
1542  *
1543  * A first pass is performed to compute the size of the buffer that must be
1544  * allocated. A second pass is then performed to setup the returned events so
1545  * that their members always point within the buffer.
1546  *
1547  * The layout of the returned buffer is as follows:
1548  *   - struct lttng_event[nb_events],
1549  *   - nb_events times the following:
1550  *     - struct lttng_event_extended,
1551  *     - filter_expression
1552  *     - exclusions
1553  *     - padding to align to 64-bits
1554  *     - flattened version of userspace_probe_location
1555  */
1556 static enum lttng_error_code flatten_lttng_events(
1557                 struct lttng_dynamic_pointer_array *events,
1558                 struct lttng_event **flattened_events)
1559 {
1560         enum lttng_error_code ret_code;
1561         int ret, i;
1562         size_t storage_req;
1563         struct lttng_dynamic_buffer local_flattened_events;
1564         int nb_events;
1565
1566         assert(events);
1567         assert(flattened_events);
1568
1569         lttng_dynamic_buffer_init(&local_flattened_events);
1570         nb_events = lttng_dynamic_pointer_array_get_count(events);
1571
1572         ret_code = compute_flattened_size(events, &storage_req);
1573         if (ret_code != LTTNG_OK) {
1574                 goto end;
1575         }
1576
1577         /*
1578          * We must ensure that "local_flattened_events" is never resized so as
1579          * to preserve the validity of the flattened objects.
1580          */
1581         ret = lttng_dynamic_buffer_set_capacity(
1582                         &local_flattened_events, storage_req);
1583         if (ret) {
1584                 ret_code = LTTNG_ERR_NOMEM;
1585                 goto end;
1586         }
1587
1588         /* Start by laying the struct lttng_event */
1589         for (i = 0; i < nb_events; i++) {
1590                 const struct event_list_element *element = (const struct event_list_element *)
1591                                 lttng_dynamic_pointer_array_get_pointer(
1592                                                 events, i);
1593
1594                 if (!element) {
1595                         ret_code = LTTNG_ERR_FATAL;
1596                         goto end;
1597                 }
1598
1599                 ret = lttng_dynamic_buffer_append(&local_flattened_events,
1600                                 element->event, sizeof(struct lttng_event));
1601                 if (ret) {
1602                         ret_code = LTTNG_ERR_NOMEM;
1603                         goto end;
1604                 }
1605         }
1606
1607         for (i = 0; i < nb_events; i++) {
1608                 const struct event_list_element *element = (const struct event_list_element *)
1609                                 lttng_dynamic_pointer_array_get_pointer(events, i);
1610                 struct lttng_event *event = (struct lttng_event *)
1611                         (local_flattened_events.data + (sizeof(struct lttng_event) * i));
1612                 struct lttng_event_extended *event_extended =
1613                         (struct lttng_event_extended *)
1614                                 (local_flattened_events.data + local_flattened_events.size);
1615                 const struct lttng_userspace_probe_location *location = NULL;
1616
1617                 assert(element);
1618
1619                 /* Insert struct lttng_event_extended. */
1620                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1621                                 local_flattened_events.size +
1622                                                 sizeof(*event_extended));
1623                 if (ret) {
1624                         ret_code = LTTNG_ERR_NOMEM;
1625                         goto end;
1626                 }
1627                 event->extended.ptr = event_extended;
1628
1629                 /* Insert filter expression. */
1630                 if (element->filter_expression) {
1631                         const size_t len = strlen(element->filter_expression) + 1;
1632
1633                         event_extended->filter_expression =
1634                                         local_flattened_events.data +
1635                                         local_flattened_events.size;
1636                         ret = lttng_dynamic_buffer_append(
1637                                         &local_flattened_events,
1638                                         element->filter_expression, len);
1639                         if (ret) {
1640                                 ret_code = LTTNG_ERR_NOMEM;
1641                                 goto end;
1642                         }
1643                 }
1644
1645                 /* Insert exclusions. */
1646                 if (element->exclusions) {
1647                         event_extended->exclusions.count =
1648                                         element->exclusions->count;
1649                         event_extended->exclusions.strings =
1650                                         local_flattened_events.data +
1651                                         local_flattened_events.size;
1652
1653                         ret = lttng_dynamic_buffer_append(
1654                                         &local_flattened_events,
1655                                         element->exclusions->names,
1656                                         element->exclusions->count *
1657                                                         LTTNG_SYMBOL_NAME_LEN);
1658                         if (ret) {
1659                                 ret_code = LTTNG_ERR_NOMEM;
1660                                 goto end;
1661                         }
1662                 }
1663
1664                 /* Insert padding to align to 64-bits. */
1665                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1666                                 lttng_align_ceil(local_flattened_events.size,
1667                                                 sizeof(uint64_t)));
1668                 if (ret) {
1669                         ret_code = LTTNG_ERR_NOMEM;
1670                         goto end;
1671                 }
1672
1673                 location = lttng_event_get_userspace_probe_location(
1674                                 element->event);
1675                 if (location) {
1676                         event_extended->probe_location = (struct lttng_userspace_probe_location *)
1677                                         (local_flattened_events.data + local_flattened_events.size);
1678                         ret = lttng_userspace_probe_location_flatten(
1679                                         location, &local_flattened_events);
1680                         if (ret < 0) {
1681                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1682                                 goto end;
1683                         }
1684                 }
1685         }
1686
1687         /* Don't reset local_flattened_events buffer as we return its content. */
1688         *flattened_events = (struct lttng_event *) local_flattened_events.data;
1689         lttng_dynamic_buffer_init(&local_flattened_events);
1690         ret_code = LTTNG_OK;
1691 end:
1692         lttng_dynamic_buffer_reset(&local_flattened_events);
1693         return ret_code;
1694 }
1695
1696 static enum lttng_error_code event_list_create_from_payload(
1697                 struct lttng_payload_view *view,
1698                 unsigned int count,
1699                 struct lttng_dynamic_pointer_array *event_list)
1700 {
1701         enum lttng_error_code ret_code;
1702         int ret;
1703         unsigned int i;
1704         int offset = 0;
1705
1706         assert(view);
1707         assert(event_list);
1708
1709         for (i = 0; i < count; i++) {
1710                 ssize_t event_size;
1711                 struct lttng_payload_view event_view =
1712                                 lttng_payload_view_from_view(view, offset, -1);
1713                 struct event_list_element *element = zmalloc<event_list_element>();
1714
1715                 if (!element) {
1716                         ret_code = LTTNG_ERR_NOMEM;
1717                         goto end;
1718                 }
1719
1720                 /*
1721                  * Lifetime and management of the object is now bound to the
1722                  * array.
1723                  */
1724                 ret = lttng_dynamic_pointer_array_add_pointer(
1725                                 event_list, element);
1726                 if (ret) {
1727                         event_list_destructor(element);
1728                         ret_code = LTTNG_ERR_NOMEM;
1729                         goto end;
1730                 }
1731
1732                 /*
1733                  * Bytecode is not transmitted on listing in any case we do not
1734                  * care about it.
1735                  */
1736                 event_size = lttng_event_create_from_payload(&event_view,
1737                                 &element->event,
1738                                 &element->exclusions,
1739                                 &element->filter_expression, NULL);
1740                 if (event_size < 0) {
1741                         ret_code = LTTNG_ERR_INVALID;
1742                         goto end;
1743                 }
1744
1745                 offset += event_size;
1746         }
1747
1748         if (view->buffer.size != offset) {
1749                 ret_code = LTTNG_ERR_INVALID_PROTOCOL;
1750                 goto end;
1751         }
1752
1753         ret_code = LTTNG_OK;
1754
1755 end:
1756         return ret_code;
1757 }
1758
1759 enum lttng_error_code lttng_events_create_and_flatten_from_payload(
1760                 struct lttng_payload_view *payload,
1761                 unsigned int count,
1762                 struct lttng_event **events)
1763 {
1764         enum lttng_error_code ret = LTTNG_OK;
1765         struct lttng_dynamic_pointer_array local_events;
1766
1767         lttng_dynamic_pointer_array_init(&local_events, event_list_destructor);
1768
1769         /* Deserialize the events. */
1770         {
1771                 struct lttng_payload_view events_view =
1772                                 lttng_payload_view_from_view(payload, 0, -1);
1773
1774                 ret = event_list_create_from_payload(
1775                                 &events_view, count, &local_events);
1776                 if (ret != LTTNG_OK) {
1777                         goto end;
1778                 }
1779         }
1780
1781         ret = flatten_lttng_events(&local_events, events);
1782         if (ret != LTTNG_OK) {
1783                 goto end;
1784         }
1785
1786 end:
1787         lttng_dynamic_pointer_array_reset(&local_events);
1788         return ret;
1789 }
1790
1791 static enum lttng_error_code flatten_lttng_event_fields(
1792                 struct lttng_dynamic_pointer_array *event_fields,
1793                 struct lttng_event_field **flattened_event_fields)
1794 {
1795         int ret, i;
1796         enum lttng_error_code ret_code;
1797         size_t storage_req = 0;
1798         struct lttng_dynamic_buffer local_flattened_event_fields;
1799         int nb_event_field;
1800
1801         assert(event_fields);
1802         assert(flattened_event_fields);
1803
1804         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1805         nb_event_field = lttng_dynamic_pointer_array_get_count(event_fields);
1806
1807         /*
1808          * Here even if the event field contains a `struct lttng_event` that
1809          * could contain dynamic data, in reality it is not the case.
1810          * Dynamic data is not present. Here the flattening is mostly a direct
1811          * memcpy. This is less than ideal but this code is still better than
1812          * direct usage of an unpacked lttng_event_field array.
1813          */
1814         storage_req += sizeof(struct lttng_event_field) * nb_event_field;
1815
1816         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1817
1818         /*
1819          * We must ensure that "local_flattened_event_fields" is never resized
1820          * so as to preserve the validity of the flattened objects.
1821          */
1822         ret = lttng_dynamic_buffer_set_capacity(
1823                         &local_flattened_event_fields, storage_req);
1824         if (ret) {
1825                 ret_code = LTTNG_ERR_NOMEM;
1826                 goto end;
1827         }
1828
1829         for (i = 0; i < nb_event_field; i++) {
1830                 const struct lttng_event_field *element =
1831                                 (const struct lttng_event_field *)
1832                                         lttng_dynamic_pointer_array_get_pointer(
1833                                                 event_fields, i);
1834
1835                 if (!element) {
1836                         ret_code = LTTNG_ERR_FATAL;
1837                         goto end;
1838                 }
1839                 ret = lttng_dynamic_buffer_append(&local_flattened_event_fields,
1840                                 element, sizeof(struct lttng_event_field));
1841                 if (ret) {
1842                         ret_code = LTTNG_ERR_NOMEM;
1843                         goto end;
1844                 }
1845         }
1846
1847         /* Don't reset local_flattened_channels buffer as we return its content. */
1848         *flattened_event_fields = (struct lttng_event_field *) local_flattened_event_fields.data;
1849         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1850         ret_code = LTTNG_OK;
1851 end:
1852         lttng_dynamic_buffer_reset(&local_flattened_event_fields);
1853         return ret_code;
1854 }
1855
1856 static enum lttng_error_code event_field_list_create_from_payload(
1857                 struct lttng_payload_view *view,
1858                 unsigned int count,
1859                 struct lttng_dynamic_pointer_array **event_field_list)
1860 {
1861         enum lttng_error_code ret_code;
1862         int ret, offset = 0;
1863         unsigned int i;
1864         struct lttng_dynamic_pointer_array *list = NULL;
1865
1866         assert(view);
1867         assert(event_field_list);
1868
1869         list = zmalloc<lttng_dynamic_pointer_array>();
1870         if (!list) {
1871                 ret_code = LTTNG_ERR_NOMEM;
1872                 goto end;
1873         }
1874
1875         lttng_dynamic_pointer_array_init(list, free);
1876
1877         for (i = 0; i < count; i++) {
1878                 ssize_t event_field_size;
1879                 struct lttng_event_field *field = NULL;
1880                 struct lttng_payload_view event_field_view =
1881                                 lttng_payload_view_from_view(view, offset, -1);
1882
1883                 event_field_size = lttng_event_field_create_from_payload(
1884                                 &event_field_view, &field);
1885                 if (event_field_size < 0) {
1886                         ret_code = LTTNG_ERR_INVALID;
1887                         goto end;
1888                 }
1889
1890                 /* Lifetime and management of the object is now bound to the array. */
1891                 ret = lttng_dynamic_pointer_array_add_pointer(list, field);
1892                 if (ret) {
1893                         free(field);
1894                         ret_code = LTTNG_ERR_NOMEM;
1895                         goto end;
1896                 }
1897
1898                 offset += event_field_size;
1899         }
1900
1901         if (view->buffer.size != offset) {
1902                 ret_code = LTTNG_ERR_INVALID;
1903                 goto end;
1904         }
1905
1906         *event_field_list = list;
1907         list = NULL;
1908         ret_code = LTTNG_OK;
1909
1910 end:
1911         if (list) {
1912                 lttng_dynamic_pointer_array_reset(list);
1913                 free(list);
1914         }
1915
1916         return ret_code;
1917 }
1918
1919 enum lttng_error_code lttng_event_fields_create_and_flatten_from_payload(
1920                 struct lttng_payload_view *view,
1921                 unsigned int count,
1922                 struct lttng_event_field **fields)
1923 {
1924         enum lttng_error_code ret_code;
1925         struct lttng_dynamic_pointer_array *local_event_fields = NULL;
1926
1927         ret_code = event_field_list_create_from_payload(
1928                         view, count, &local_event_fields);
1929         if (ret_code != LTTNG_OK) {
1930                 goto end;
1931         }
1932
1933         ret_code = flatten_lttng_event_fields(local_event_fields, fields);
1934         if (ret_code != LTTNG_OK) {
1935                 goto end;
1936         }
1937 end:
1938         if (local_event_fields) {
1939                 lttng_dynamic_pointer_array_reset(local_event_fields);
1940                 free(local_event_fields);
1941         }
1942
1943         return ret_code;
1944 }