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/compat/string.h"
   9 #include "common/macros.h"
  10 #include "lttng/lttng-error.h"
  11 #include <assert.h>
  12 #include <common/buffer-view.h>
  13 #include <common/dynamic-array.h>
  14 #include <common/dynamic-buffer.h>
  15 #include <common/error.h>
  16 #include <common/sessiond-comm/sessiond-comm.h>
  17 #include <common/align.h>
  18 #include <lttng/constant.h>
  19 #include <lttng/event-internal.h>
  20 #include <lttng/event.h>
  21 #include <lttng/userspace-probe-internal.h>
  22 #include <stdint.h>
  23 #include <string.h>
  24
  25 struct event_list_element {
  26         struct lttng_event *event;
  27         struct lttng_event_exclusion *exclusions;
  28         char *filter_expression;
  29 };
  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 = (lttng_event *) zmalloc(sizeof(*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 = (lttng_event_extended *) zmalloc(sizeof(*new_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 = { 0 };
  81
  82         symbol_name_len = lttng_strnlen(probe->symbol_name, LTTNG_SYMBOL_NAME_LEN);
  83         if (symbol_name_len == LTTNG_SYMBOL_NAME_LEN) {
  84                 /* Not null-termintated. */
  85                 ret = -1;
  86                 goto end;
  87         }
  88
  89         /* Include the null terminator. */
  90         symbol_name_len += 1;
  91
  92         comm.symbol_name_len = (uint32_t) symbol_name_len;
  93         comm.addr = probe->addr;
  94         comm.offset = probe->addr;
  95
  96         ret = lttng_dynamic_buffer_append(
  97                         &payload->buffer, &comm, sizeof(comm));
  98         if (ret < 0) {
  99                 ret = -1;
 100                 goto end;
 101         }
 102
 103         ret = lttng_dynamic_buffer_append(
 104                         &payload->buffer, probe->symbol_name, symbol_name_len);
 105 end:
 106         return ret;
 107 }
 108
 109 static int lttng_event_function_attr_serialize(
 110                 const struct lttng_event_function_attr *function,
 111                 struct lttng_payload *payload)
 112 {
 113         int ret;
 114         size_t symbol_name_len;
 115         struct lttng_event_function_attr_comm comm = { 0 };
 116
 117         symbol_name_len = lttng_strnlen(function->symbol_name, LTTNG_SYMBOL_NAME_LEN);
 118         if (symbol_name_len == LTTNG_SYMBOL_NAME_LEN) {
 119                 /* Not null-termintated. */
 120                 ret = -1;
 121                 goto end;
 122         }
 123
 124         /* Include the null terminator. */
 125         symbol_name_len += 1;
 126
 127         comm.symbol_name_len = (uint32_t) symbol_name_len;
 128
 129         ret = lttng_dynamic_buffer_append(
 130                         &payload->buffer, &comm, sizeof(comm));
 131         if (ret < 0) {
 132                 ret = -1;
 133                 goto end;
 134         }
 135
 136         ret = lttng_dynamic_buffer_append(&payload->buffer,
 137                         function->symbol_name, symbol_name_len);
 138 end:
 139         return ret;
 140 }
 141
 142 static ssize_t lttng_event_probe_attr_create_from_payload(
 143                 struct lttng_payload_view *view,
 144                 struct lttng_event_probe_attr **probe_attr)
 145 {
 146         ssize_t ret, offset = 0;
 147         const struct lttng_event_probe_attr_comm *comm;
 148         struct lttng_event_probe_attr *local_attr = NULL;
 149         struct lttng_payload_view comm_view = lttng_payload_view_from_view(
 150                         view, offset, sizeof(*comm));
 151
 152         if (!lttng_payload_view_is_valid(&comm_view)) {
 153                 ret = -1;
 154                 goto end;
 155         }
 156
 157         comm = (typeof(comm)) comm_view.buffer.data;
 158         offset += sizeof(*comm);
 159
 160         local_attr = (struct lttng_event_probe_attr *) zmalloc(
 161                         sizeof(*local_attr));
 162         if (local_attr == NULL) {
 163                 ret = -1;
 164                 goto end;
 165         }
 166
 167         local_attr->addr = comm->addr;
 168         local_attr->offset = comm->offset;
 169
 170         {
 171                 const char *name;
 172                 struct lttng_payload_view name_view =
 173                                 lttng_payload_view_from_view(view, offset,
 174                                                 comm->symbol_name_len);
 175
 176                 if (!lttng_payload_view_is_valid(&name_view)) {
 177                         ret = -1;
 178                         goto end;
 179                 }
 180
 181                 name = name_view.buffer.data;
 182
 183                 if (!lttng_buffer_view_contains_string(&name_view.buffer, name,
 184                                     comm->symbol_name_len)) {
 185                         ret = -1;
 186                         goto end;
 187                 }
 188
 189                 ret = lttng_strncpy(local_attr->symbol_name, name,
 190                                 LTTNG_SYMBOL_NAME_LEN);
 191                 if (ret) {
 192                         ret = -1;
 193                         goto end;
 194                 }
 195
 196                 offset += comm->symbol_name_len;
 197         }
 198
 199         *probe_attr = local_attr;
 200         local_attr = NULL;
 201         ret = offset;
 202 end:
 203         free(local_attr);
 204         return ret;
 205 }
 206
 207 static ssize_t lttng_event_function_attr_create_from_payload(
 208                 struct lttng_payload_view *view,
 209                 struct lttng_event_function_attr **function_attr)
 210 {
 211         ssize_t ret, offset = 0;
 212         const struct lttng_event_function_attr_comm *comm;
 213         struct lttng_event_function_attr *local_attr = NULL;
 214         struct lttng_payload_view comm_view = lttng_payload_view_from_view(
 215                         view, offset, sizeof(*comm));
 216
 217         if (!lttng_payload_view_is_valid(&comm_view)) {
 218                 ret = -1;
 219                 goto end;
 220         }
 221
 222         comm = (typeof(comm)) view->buffer.data;
 223         offset += sizeof(*comm);
 224
 225         local_attr = (struct lttng_event_function_attr *) zmalloc(
 226                         sizeof(*local_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                                 LTTNG_SYMBOL_NAME_LEN);
 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         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 = (struct lttng_event_exclusion *) zmalloc(
 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(local_exclusions->names[i],
 321                                 string, LTTNG_SYMBOL_NAME_LEN);
 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(
 410                                 local_event->name, name, LTTNG_SYMBOL_NAME_LEN);
 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 = (struct lttng_bytecode *) zmalloc(
 514                                 event_comm->bytecode_len);
 515                 if (!local_bytecode) {
 516                         ret = -1;
 517                         goto end;
 518                 }
 519
 520                 memcpy(local_bytecode, bytecode_view.buffer.data,
 521                                 event_comm->bytecode_len);
 522                 if ((local_bytecode->len + sizeof(*local_bytecode)) !=
 523                                 event_comm->bytecode_len) {
 524                         ret = -1;
 525                         goto end;
 526                 }
 527
 528                 offset += event_comm->bytecode_len;
 529         }
 530
 531 deserialize_event_type_payload:
 532         /* Event type specific payload */
 533         switch (local_event->type) {
 534         case LTTNG_EVENT_FUNCTION:
 535                 /* Fallthrough */
 536         case LTTNG_EVENT_PROBE:
 537         {
 538                 struct lttng_payload_view probe_attr_view =
 539                                 lttng_payload_view_from_view(view, offset,
 540                                                 event_comm->lttng_event_probe_attr_len);
 541
 542                 if (event_comm->lttng_event_probe_attr_len == 0) {
 543                         ret = -1;
 544                         goto end;
 545                 }
 546
 547                 if (!lttng_payload_view_is_valid(&probe_attr_view)) {
 548                         ret = -1;
 549                         goto end;
 550                 }
 551
 552                 ret = lttng_event_probe_attr_create_from_payload(
 553                                 &probe_attr_view, &local_probe_attr);
 554                 if (ret < 0 || ret != event_comm->lttng_event_probe_attr_len) {
 555                         ret = -1;
 556                         goto end;
 557                 }
 558
 559                 /* Copy to the local event. */
 560                 memcpy(&local_event->attr.probe, local_probe_attr,
 561                                 sizeof(local_event->attr.probe));
 562
 563                 offset += ret;
 564                 break;
 565         }
 566         case LTTNG_EVENT_FUNCTION_ENTRY:
 567         {
 568                 struct lttng_payload_view function_attr_view =
 569                                 lttng_payload_view_from_view(view, offset,
 570                                                 event_comm->lttng_event_function_attr_len);
 571
 572                 if (event_comm->lttng_event_function_attr_len == 0) {
 573                         ret = -1;
 574                         goto end;
 575                 }
 576
 577                 if (!lttng_payload_view_is_valid(&function_attr_view)) {
 578                         ret = -1;
 579                         goto end;
 580                 }
 581
 582                 ret = lttng_event_function_attr_create_from_payload(
 583                                 &function_attr_view, &local_function_attr);
 584                 if (ret < 0 || ret != event_comm->lttng_event_function_attr_len) {
 585                         ret = -1;
 586                         goto end;
 587                 }
 588
 589                 /* Copy to the local event. */
 590                 memcpy(&local_event->attr.ftrace, local_function_attr,
 591                                 sizeof(local_event->attr.ftrace));
 592
 593                 offset += ret;
 594
 595                 break;
 596         }
 597         case LTTNG_EVENT_USERSPACE_PROBE:
 598         {
 599                 struct lttng_payload_view userspace_probe_location_view =
 600                                 lttng_payload_view_from_view(view, offset,
 601                                                 event_comm->userspace_probe_location_len);
 602
 603                 if (event_comm->userspace_probe_location_len == 0) {
 604                         ret = -1;
 605                         goto end;
 606                 }
 607
 608                 if (!lttng_payload_view_is_valid(
 609                                     &userspace_probe_location_view)) {
 610                         ret = -1;
 611                         goto end;
 612                 }
 613
 614                 ret = lttng_userspace_probe_location_create_from_payload(
 615                                 &userspace_probe_location_view,
 616                                 &local_userspace_probe_location);
 617                 if (ret < 0) {
 618                         WARN("Failed to create a userspace probe location from the received buffer");
 619                         ret = -1;
 620                         goto end;
 621                 }
 622
 623                 if (ret != event_comm->userspace_probe_location_len) {
 624                         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);
 625                         ret = -1;
 626                         goto end;
 627                 }
 628
 629                 /* Attach the probe location to the event. */
 630                 ret = lttng_event_set_userspace_probe_location(
 631                                 local_event, local_userspace_probe_location);
 632                 if (ret) {
 633                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 634                         goto end;
 635                 }
 636
 637                 /*
 638                  * Userspace probe location object ownership transfered to the
 639                  * event object.
 640                  */
 641                 local_userspace_probe_location = NULL;
 642                 offset += event_comm->userspace_probe_location_len;
 643                 break;
 644         }
 645         case LTTNG_EVENT_TRACEPOINT:
 646                 /* Fallthrough */
 647         case LTTNG_EVENT_ALL:
 648                 /* Fallthrough */
 649         case LTTNG_EVENT_SYSCALL:
 650                 /* Fallthrough */
 651         case LTTNG_EVENT_NOOP:
 652                 /* Nothing to do here */
 653                 break;
 654         default:
 655                 ret = LTTNG_ERR_UND;
 656                 goto end;
 657                 break;
 658         }
 659
 660         /* Transfer ownership to the caller. */
 661         *out_event = local_event;
 662         local_event = NULL;
 663
 664         if (out_bytecode) {
 665                 *out_bytecode = local_bytecode;
 666                 local_bytecode = NULL;
 667         }
 668
 669         if (out_exclusion) {
 670                 *out_exclusion = local_exclusions;
 671                 local_exclusions = NULL;
 672         }
 673
 674         if (out_filter_expression) {
 675                 *out_filter_expression = local_filter_expression;
 676                 local_filter_expression = NULL;
 677         }
 678
 679         ret = offset;
 680 end:
 681         lttng_event_destroy(local_event);
 682         lttng_userspace_probe_location_destroy(local_userspace_probe_location);
 683         free(local_filter_expression);
 684         free(local_exclusions);
 685         free(local_bytecode);
 686         free(local_function_attr);
 687         free(local_probe_attr);
 688         return ret;
 689 }
 690
 691 int lttng_event_serialize(const struct lttng_event *event,
 692                 unsigned int exclusion_count,
 693                 char **exclusion_list,
 694                 char *filter_expression,
 695                 size_t bytecode_len,
 696                 struct lttng_bytecode *bytecode,
 697                 struct lttng_payload *payload)
 698 {
 699         int ret;
 700         unsigned int i;
 701         size_t header_offset, size_before_payload;
 702         size_t name_len;
 703         struct lttng_event_comm event_comm = { 0 };
 704         struct lttng_event_comm *header;
 705
 706         assert(event);
 707         assert(payload);
 708         assert(exclusion_count == 0 || exclusion_list);
 709
 710         /* Save the header location for later in-place header update. */
 711         header_offset = payload->buffer.size;
 712
 713         name_len = lttng_strnlen(event->name, LTTNG_SYMBOL_NAME_LEN);
 714         if (name_len == LTTNG_SYMBOL_NAME_LEN) {
 715                 /* Event name is not NULL-terminated. */
 716                 ret = -1;
 717                 goto end;
 718         }
 719
 720         /* Add null termination. */
 721         name_len += 1;
 722
 723         if (exclusion_count > UINT32_MAX) {
 724                 /* Possible overflow. */
 725                 ret = -1;
 726                 goto end;
 727         }
 728
 729         if (bytecode_len > UINT32_MAX) {
 730                 /* Possible overflow. */
 731                 ret = -1;
 732                 goto end;
 733         }
 734
 735         event_comm.name_len = (uint32_t) name_len;
 736         event_comm.event_type = (int8_t) event->type;
 737         event_comm.loglevel_type = (int8_t) event->loglevel_type;
 738         event_comm.loglevel = (int32_t) event->loglevel;
 739         event_comm.enabled = (int8_t) event->enabled;
 740         event_comm.pid = (int32_t) event->pid;
 741         event_comm.exclusion_count = (uint32_t) exclusion_count;
 742         event_comm.bytecode_len = (uint32_t) bytecode_len;
 743         event_comm.flags = (int32_t) event->flags;
 744
 745         if (filter_expression) {
 746                 event_comm.filter_expression_len =
 747                                 strlen(filter_expression) + 1;
 748         }
 749
 750         /* Header */
 751         ret = lttng_dynamic_buffer_append(
 752                         &payload->buffer, &event_comm, sizeof(event_comm));
 753         if (ret) {
 754                 goto end;
 755         }
 756
 757         /* Event name */
 758         ret = lttng_dynamic_buffer_append(
 759                         &payload->buffer, event->name, name_len);
 760         if (ret) {
 761                 goto end;
 762         }
 763
 764         /* Exclusions */
 765         for (i = 0; i < exclusion_count; i++) {
 766                 const size_t exclusion_len = lttng_strnlen(
 767                                 *(exclusion_list + i), LTTNG_SYMBOL_NAME_LEN);
 768                 const struct lttng_event_exclusion_comm exclusion_header = {
 769                         .len = (uint32_t) exclusion_len + 1,
 770                 };
 771
 772                 if (exclusion_len == LTTNG_SYMBOL_NAME_LEN) {
 773                         /* Exclusion is not NULL-terminated. */
 774                         ret = -1;
 775                         goto end;
 776                 }
 777
 778                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 779                                 &exclusion_header, sizeof(exclusion_header));
 780                 if (ret) {
 781                         goto end;
 782                 }
 783
 784                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 785                                 *(exclusion_list + i), exclusion_len + 1);
 786                 if (ret) {
 787                         goto end;
 788                 }
 789         }
 790
 791         /* Filter expression and its bytecode */
 792         if (filter_expression) {
 793                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 794                                 filter_expression,
 795                                 event_comm.filter_expression_len);
 796                 if (ret) {
 797                         goto end;
 798                 }
 799
 800                 /*
 801                  * Bytecode can be absent when we serialize to the client
 802                  * for listing.
 803                  */
 804                 if (bytecode) {
 805                         ret = lttng_dynamic_buffer_append(&payload->buffer,
 806                                         bytecode, bytecode_len);
 807                         if (ret) {
 808                                 goto end;
 809                         }
 810                 }
 811         }
 812
 813         size_before_payload = payload->buffer.size;
 814
 815         /* Event type specific payload */
 816         switch (event->type) {
 817         case LTTNG_EVENT_FUNCTION:
 818                 /* Fallthrough */
 819         case LTTNG_EVENT_PROBE:
 820                 ret = lttng_event_probe_attr_serialize(&event->attr.probe, payload);
 821                 if (ret) {
 822                         ret = -1;
 823                         goto end;
 824                 }
 825
 826                 header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 827                                                       header_offset);
 828                 header->lttng_event_probe_attr_len =
 829                                 payload->buffer.size - size_before_payload;
 830
 831                 break;
 832         case LTTNG_EVENT_FUNCTION_ENTRY:
 833                 ret = lttng_event_function_attr_serialize(
 834                                 &event->attr.ftrace, payload);
 835                 if (ret) {
 836                         ret = -1;
 837                         goto end;
 838                 }
 839
 840                 /* Update the lttng_event_function_attr len. */
 841                 header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 842                                                       header_offset);
 843                 header->lttng_event_function_attr_len =
 844                                 payload->buffer.size - size_before_payload;
 845
 846                 break;
 847         case LTTNG_EVENT_USERSPACE_PROBE:
 848         {
 849                 const struct lttng_event_extended *ev_ext =
 850                                 (const struct lttng_event_extended *)
 851                                                 event->extended.ptr;
 852
 853                 assert(event->extended.ptr);
 854                 assert(ev_ext->probe_location);
 855
 856                 size_before_payload = payload->buffer.size;
 857                 if (ev_ext->probe_location) {
 858                         /*
 859                          * lttng_userspace_probe_location_serialize returns the
 860                          * number of bytes that were appended to the buffer.
 861                          */
 862                         ret = lttng_userspace_probe_location_serialize(
 863                                         ev_ext->probe_location, payload);
 864                         if (ret < 0) {
 865                                 goto end;
 866                         }
 867
 868                         ret = 0;
 869
 870                         /* Update the userspace probe location len. */
 871                         header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 872                                                               header_offset);
 873                         header->userspace_probe_location_len =
 874                                         payload->buffer.size - size_before_payload;
 875                 }
 876                 break;
 877         }
 878         case LTTNG_EVENT_TRACEPOINT:
 879                 /* Fallthrough */
 880         case LTTNG_EVENT_ALL:
 881                 /* Fallthrough */
 882         default:
 883                 /* Nothing to do here. */
 884                 break;
 885         }
 886
 887 end:
 888         return ret;
 889 }
 890
 891 static ssize_t lttng_event_context_app_populate_from_payload(
 892                 const struct lttng_payload_view *view,
 893                 struct lttng_event_context *event_ctx)
 894 {
 895         ssize_t ret, offset = 0;
 896         const struct lttng_event_context_app_comm *comm;
 897         char *provider_name = NULL, *context_name = NULL;
 898         size_t provider_name_len, context_name_len;
 899         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
 900                         &view->buffer, offset, sizeof(*comm));
 901
 902         assert(event_ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
 903
 904         if (!lttng_buffer_view_is_valid(&comm_view)) {
 905                 ret = -1;
 906                 goto end;
 907         }
 908
 909         comm = (typeof(comm)) comm_view.data;
 910         offset += sizeof(*comm);
 911
 912         provider_name_len = comm->provider_name_len;
 913         context_name_len = comm->ctx_name_len;
 914
 915         if (provider_name_len == 0 || context_name_len == 0) {
 916                 /*
 917                  * Application provider and context names MUST
 918                  * be provided.
 919                  */
 920                 ret = -1;
 921                 goto end;
 922         }
 923
 924         {
 925                 const char *name;
 926                 const struct lttng_buffer_view provider_name_view =
 927                                 lttng_buffer_view_from_view(&view->buffer,
 928                                                 offset,
 929                                                 provider_name_len);
 930
 931                 if (!lttng_buffer_view_is_valid(&provider_name_view)) {
 932                         ret = -1;
 933                         goto end;
 934                 }
 935
 936                 name = provider_name_view.data;
 937
 938                 if (!lttng_buffer_view_contains_string(&provider_name_view,
 939                                 name, provider_name_len)) {
 940                         ret = -1;
 941                         goto end;
 942                 }
 943
 944                 provider_name = lttng_strndup(name, provider_name_len);
 945                 if (!provider_name) {
 946                         ret = -1;
 947                         goto end;
 948                 }
 949
 950                 offset += provider_name_len;
 951         }
 952
 953         {
 954                 const char *name;
 955                 const struct lttng_buffer_view context_name_view =
 956                                 lttng_buffer_view_from_view(
 957                                                 &view->buffer, offset,
 958                                                 context_name_len);
 959
 960                 if (!lttng_buffer_view_is_valid(&context_name_view)) {
 961                         ret = -1;
 962                         goto end;
 963                 }
 964
 965                 name = context_name_view.data;
 966
 967                 if (!lttng_buffer_view_contains_string(&context_name_view, name,
 968                                     context_name_len)) {
 969                         ret = -1;
 970                         goto end;
 971                 }
 972
 973                 context_name = lttng_strndup(name, context_name_len);
 974                 if (!context_name) {
 975                         ret = -1;
 976                         goto end;
 977                 }
 978
 979                 offset += context_name_len;
 980         }
 981
 982         /* Transfer ownership of the strings */
 983         event_ctx->u.app_ctx.provider_name = provider_name;
 984         event_ctx->u.app_ctx.ctx_name = context_name;
 985         provider_name = NULL;
 986         context_name = NULL;
 987
 988         ret = offset;
 989 end:
 990         free(provider_name);
 991         free(context_name);
 992
 993         return ret;
 994 }
 995
 996 static ssize_t lttng_event_context_perf_counter_populate_from_payload(
 997                 const struct lttng_payload_view *view,
 998                 struct lttng_event_context *event_ctx)
 999 {
1000         ssize_t ret, 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                 ret = -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                         ret = -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                         ret = -1;
1038                         goto end;
1039                 }
1040
1041                 lttng_strncpy(event_ctx->u.perf_counter.name, name, name_len);
1042                 offset += name_len;
1043         }
1044
1045         event_ctx->u.perf_counter.config = comm->config;
1046         event_ctx->u.perf_counter.type = comm->type;
1047
1048         ret = offset;
1049
1050 end:
1051         return ret;
1052 }
1053
1054 ssize_t lttng_event_context_create_from_payload(
1055                 struct lttng_payload_view *view,
1056                 struct lttng_event_context **event_ctx)
1057 {
1058         ssize_t ret, offset = 0;
1059         const struct lttng_event_context_comm *comm;
1060         struct lttng_event_context *local_context = NULL;
1061         struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
1062                         &view->buffer, offset, sizeof(*comm));
1063
1064         assert(event_ctx);
1065         assert(view);
1066
1067         if (!lttng_buffer_view_is_valid(&comm_view)) {
1068                 ret = -1;
1069                 goto end;
1070         }
1071
1072         comm = (typeof(comm)) comm_view.data;
1073         offset += sizeof(*comm);
1074
1075         local_context = (struct lttng_event_context *)
1076                         zmalloc(sizeof(*local_context));
1077         if (!local_context) {
1078                 ret = -1;
1079                 goto end;
1080         }
1081
1082         local_context->ctx = (lttng_event_context_type) comm->type;
1083
1084         {
1085                 struct lttng_payload_view subtype_view =
1086                                 lttng_payload_view_from_view(view, offset, -1);
1087
1088                 switch (local_context->ctx) {
1089                 case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1090                         ret = lttng_event_context_app_populate_from_payload(
1091                                         &subtype_view, local_context);
1092                         break;
1093                 case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1094                 case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1095                 case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1096                         ret = lttng_event_context_perf_counter_populate_from_payload(
1097                                         &subtype_view, local_context);
1098                         break;
1099                 default:
1100                         /* Nothing else to deserialize. */
1101                         ret = 0;
1102                         break;
1103                 }
1104         }
1105
1106         if (ret < 0) {
1107                 goto end;
1108         }
1109
1110         offset += ret;
1111
1112         *event_ctx = local_context;
1113         local_context = NULL;
1114         ret = offset;
1115
1116 end:
1117         free(local_context);
1118         return ret;
1119 }
1120
1121 static int lttng_event_context_app_serialize(
1122                 struct lttng_event_context *context,
1123                 struct lttng_payload *payload)
1124 {
1125         int ret;
1126         struct lttng_event_context_app_comm comm = { 0 };
1127         size_t provider_len, ctx_len;
1128         const char *provider_name;
1129         const char *ctx_name;
1130
1131         assert(payload);
1132         assert(context);
1133         assert(context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
1134
1135         provider_name = context->u.app_ctx.provider_name;
1136         ctx_name = context->u.app_ctx.ctx_name;
1137
1138         if (!provider_name || !ctx_name) {
1139                 ret = -LTTNG_ERR_INVALID;
1140                 goto end;
1141         }
1142
1143         provider_len = strlen(provider_name);
1144         if (provider_len == 0) {
1145                 ret = -LTTNG_ERR_INVALID;
1146                 goto end;
1147         }
1148
1149         /* Include the null terminator. */
1150         provider_len += 1;
1151         comm.provider_name_len = provider_len;
1152
1153         ctx_len = strlen(ctx_name);
1154         if (ctx_len == 0) {
1155                 ret = -LTTNG_ERR_INVALID;
1156                 goto end;
1157         }
1158
1159         /* Include the null terminator. */
1160         ctx_len += 1;
1161         comm.ctx_name_len = ctx_len;
1162
1163         /* Header */
1164         ret = lttng_dynamic_buffer_append(&payload->buffer, &comm,
1165                         sizeof(comm));
1166         if (ret) {
1167                 ret = -1;
1168                 goto end;
1169         }
1170
1171         ret = lttng_dynamic_buffer_append(&payload->buffer, provider_name,
1172                         provider_len);
1173         if (ret) {
1174                 ret = -1;
1175                 goto end;
1176         }
1177
1178         ret = lttng_dynamic_buffer_append(&payload->buffer, ctx_name,
1179                         ctx_len);
1180         if (ret) {
1181                 ret = -1;
1182                 goto end;
1183         }
1184
1185 end:
1186         return ret;
1187 }
1188
1189 static int lttng_event_context_perf_counter_serialize(
1190                 struct lttng_event_perf_counter_ctx *context,
1191                 struct lttng_payload *payload)
1192 {
1193         int ret;
1194         struct lttng_event_context_perf_counter_comm comm = { 0 };
1195
1196         assert(payload);
1197         assert(context);
1198
1199         comm.config = context->config;
1200         comm.type = context->type;
1201         comm.name_len = lttng_strnlen(context->name, LTTNG_SYMBOL_NAME_LEN);
1202
1203         if (comm.name_len == LTTNG_SYMBOL_NAME_LEN) {
1204                 ret = -1;
1205                 goto end;
1206         }
1207
1208         /* Include the null terminator. */
1209         comm.name_len += 1;
1210
1211         /* Header */
1212         ret = lttng_dynamic_buffer_append(&payload->buffer, &comm,
1213                         sizeof(comm));
1214         if (ret) {
1215                 ret = -1;
1216                 goto end;
1217         }
1218
1219         ret = lttng_dynamic_buffer_append(&payload->buffer, context->name,
1220                         comm.name_len);
1221         if (ret) {
1222                 ret = -1;
1223                 goto end;
1224         }
1225
1226 end:
1227         return ret;
1228 }
1229
1230 int lttng_event_context_serialize(struct lttng_event_context *context,
1231                 struct lttng_payload *payload)
1232 {
1233         int ret;
1234         struct lttng_event_context_comm context_comm = { 0 };
1235
1236         assert(context);
1237         assert(payload);
1238
1239         context_comm.type = (uint32_t) context->ctx;
1240
1241         /* Header */
1242         ret = lttng_dynamic_buffer_append(
1243                         &payload->buffer, &context_comm, sizeof(context_comm));
1244         if (ret) {
1245                 goto end;
1246         }
1247
1248         switch (context->ctx) {
1249         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1250                 ret = lttng_event_context_app_serialize(context, payload);
1251                 break;
1252         case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1253         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1254         case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1255                 ret = lttng_event_context_perf_counter_serialize(
1256                                 &context->u.perf_counter, payload);
1257                 break;
1258         default:
1259                 /* Nothing else to serialize. */
1260                 break;
1261         }
1262
1263         if (ret) {
1264                 goto end;
1265         }
1266
1267 end:
1268         return ret;
1269 }
1270
1271 void lttng_event_context_destroy(struct lttng_event_context *context)
1272 {
1273         if (!context) {
1274                 return;
1275         }
1276
1277         if (context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
1278                 free(context->u.app_ctx.provider_name);
1279                 free(context->u.app_ctx.ctx_name);
1280         }
1281
1282         free(context);
1283 }
1284
1285 /*
1286  * This is a specialized populate for lttng_event_field since it ignores
1287  * the extension field of the lttng_event struct and simply copies what it can
1288  * to the internal struct lttng_event of a lttng_event_field.
1289  */
1290 static void lttng_event_field_populate_lttng_event_from_event(
1291                 const struct lttng_event *src, struct lttng_event *destination)
1292 {
1293         memcpy(destination, src, sizeof(*destination));
1294
1295         /* Remove all possible dynamic data from the destination event rule. */
1296         destination->extended.ptr = NULL;
1297 }
1298
1299 ssize_t lttng_event_field_create_from_payload(
1300                 struct lttng_payload_view *view,
1301                 struct lttng_event_field **field)
1302 {
1303         ssize_t ret, offset = 0;
1304         struct lttng_event_field *local_event_field = NULL;
1305         struct lttng_event *event = NULL;
1306         const struct lttng_event_field_comm *comm;
1307         const char* name = NULL;
1308
1309         assert(field);
1310         assert(view);
1311
1312         {
1313                 const struct lttng_buffer_view comm_view =
1314                                 lttng_buffer_view_from_view(
1315                                                 &view->buffer, offset,
1316                                                 sizeof(*comm));
1317
1318                 if (!lttng_buffer_view_is_valid(&comm_view)) {
1319                         ret = -1;
1320                         goto end;
1321                 }
1322
1323                 /* lttng_event_field_comm header */
1324                 comm = (const lttng_event_field_comm *) comm_view.data;
1325                 offset += sizeof(*comm);
1326         }
1327
1328         local_event_field = (struct lttng_event_field *)
1329                         zmalloc(sizeof(*local_event_field));
1330         if (!local_event_field) {
1331                 ret = -1;
1332                 goto end;
1333         }
1334
1335         local_event_field->type = (lttng_event_field_type) comm->type;
1336         local_event_field->nowrite = comm->nowrite;
1337
1338         /* Field name */
1339         {
1340                 const struct lttng_buffer_view name_view =
1341                                 lttng_buffer_view_from_view(
1342                                                 &view->buffer, offset,
1343                                                 comm->name_len);
1344
1345                 if (!lttng_buffer_view_is_valid(&name_view)) {
1346                         ret = -1;
1347                         goto end;
1348                 }
1349
1350                 name = name_view.data;
1351
1352                 if (!lttng_buffer_view_contains_string(&name_view,
1353                                 name_view.data, comm->name_len)) {
1354                         ret = -1;
1355                         goto end;
1356                 }
1357
1358                 if (comm->name_len > LTTNG_SYMBOL_NAME_LEN - 1) {
1359                         /* Name is too long.*/
1360                         ret = -1;
1361                         goto end;
1362                 }
1363
1364                 offset += comm->name_len;
1365         }
1366
1367         /* Event */
1368         {
1369                 struct lttng_payload_view event_view =
1370                                 lttng_payload_view_from_view(
1371                                                 view, offset,
1372                                                 comm->event_len);
1373
1374                 if (!lttng_payload_view_is_valid(&event_view)) {
1375                         ret = -1;
1376                         goto end;
1377                 }
1378
1379                 ret = lttng_event_create_from_payload(&event_view, &event, NULL,
1380                                 NULL, NULL);
1381                 if (ret != comm->event_len) {
1382                         ret = -1;
1383                         goto end;
1384                 }
1385
1386                 offset += ret;
1387         }
1388
1389         assert(name);
1390         assert(event);
1391
1392         if (lttng_strncpy(local_event_field->field_name, name , LTTNG_SYMBOL_NAME_LEN)) {
1393                 ret = -1;
1394                 goto end;
1395         }
1396
1397         lttng_event_field_populate_lttng_event_from_event(
1398                         event, &local_event_field->event);
1399
1400         *field = local_event_field;
1401         local_event_field = NULL;
1402         ret = offset;
1403 end:
1404         lttng_event_destroy(event);
1405         free(local_event_field);
1406         return ret;
1407 }
1408
1409 int lttng_event_field_serialize(const struct lttng_event_field *field,
1410                 struct lttng_payload *payload)
1411 {
1412         int ret;
1413         size_t header_offset, size_before_event;
1414         size_t name_len;
1415         struct lttng_event_field_comm event_field_comm = { 0 };
1416         struct lttng_event_field_comm *header;
1417
1418         assert(field);
1419         assert(payload);
1420
1421         /* Save the header location for later in-place header update. */
1422         header_offset = payload->buffer.size;
1423
1424         name_len = strnlen(field->field_name, LTTNG_SYMBOL_NAME_LEN);
1425         if (name_len == LTTNG_SYMBOL_NAME_LEN) {
1426                 /* Event name is not NULL-terminated. */
1427                 ret = -1;
1428                 goto end;
1429         }
1430
1431         /* Add null termination. */
1432         name_len += 1;
1433
1434         event_field_comm.type = field->type;
1435         event_field_comm.nowrite = (uint8_t)field->nowrite;
1436         event_field_comm.name_len = name_len;
1437
1438         /* Header */
1439         ret = lttng_dynamic_buffer_append(
1440                         &payload->buffer, &event_field_comm,
1441                         sizeof(event_field_comm));
1442         if (ret) {
1443                 goto end;
1444         }
1445
1446         /* Field name */
1447         ret = lttng_dynamic_buffer_append(&payload->buffer, field->field_name,
1448                         name_len);
1449         if (ret) {
1450                 goto end;
1451         }
1452
1453         size_before_event = payload->buffer.size;
1454         ret = lttng_event_serialize(
1455                         &field->event, 0, NULL, NULL, 0, 0, payload);
1456         if (ret) {
1457                 ret = -1;
1458                 goto end;
1459         }
1460
1461         /* Update the event len. */
1462         header = (struct lttng_event_field_comm *)
1463                         ((char *) payload->buffer.data +
1464                                 header_offset);
1465         header->event_len = payload->buffer.size - size_before_event;
1466
1467 end:
1468         return ret;
1469 }
1470
1471 static enum lttng_error_code compute_flattened_size(
1472                 struct lttng_dynamic_pointer_array *events, size_t *size)
1473 {
1474         enum lttng_error_code ret_code;
1475         int ret = 0;
1476         size_t storage_req, event_count, i;
1477
1478         assert(size);
1479         assert(events);
1480
1481         event_count = lttng_dynamic_pointer_array_get_count(events);
1482
1483         /* The basic struct lttng_event */
1484         storage_req = event_count * sizeof(struct lttng_event);
1485
1486         for (i = 0; i < event_count; i++) {
1487                 int probe_storage_req = 0;
1488                 const struct event_list_element *element = (const struct event_list_element *)
1489                                 lttng_dynamic_pointer_array_get_pointer(
1490                                                 events, i);
1491                 const struct lttng_userspace_probe_location *location = NULL;
1492
1493                 location = lttng_event_get_userspace_probe_location(
1494                                 element->event);
1495                 if (location) {
1496                         ret = lttng_userspace_probe_location_flatten(
1497                                         location, NULL);
1498                         if (ret < 0) {
1499                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1500                                 goto end;
1501                         }
1502
1503                         probe_storage_req = ret;
1504                 }
1505
1506                 /* The struct·lttng_event_extended */
1507                 storage_req += event_count *
1508                         sizeof(struct lttng_event_extended);
1509
1510                 if (element->filter_expression) {
1511                         storage_req += strlen(element->filter_expression) + 1;
1512                 }
1513
1514                 if (element->exclusions) {
1515                         storage_req += element->exclusions->count *
1516                                 LTTNG_SYMBOL_NAME_LEN;
1517                 }
1518
1519                 /* Padding to ensure the flat probe is aligned. */
1520                 storage_req = lttng_align_ceil(storage_req, sizeof(uint64_t));
1521                 storage_req += probe_storage_req;
1522         }
1523
1524         *size = storage_req;
1525         ret_code = LTTNG_OK;
1526
1527 end:
1528         return ret_code;
1529 }
1530
1531 /*
1532  * Flatten a list of struct lttng_event.
1533  *
1534  * The buffer that is returned to the API client  must contain a "flat" version
1535  * of the events that are returned. In other words, all pointers within an
1536  * lttng_event must point to a location within the returned buffer so that the
1537  * user may free everything by simply calling free() on the returned buffer.
1538  * This is needed in order to maintain API compatibility.
1539  *
1540  * A first pass is performed to compute the size of the buffer that must be
1541  * allocated. A second pass is then performed to setup the returned events so
1542  * that their members always point within the buffer.
1543  *
1544  * The layout of the returned buffer is as follows:
1545  *   - struct lttng_event[nb_events],
1546  *   - nb_events times the following:
1547  *     - struct lttng_event_extended,
1548  *     - filter_expression
1549  *     - exclusions
1550  *     - padding to align to 64-bits
1551  *     - flattened version of userspace_probe_location
1552  */
1553 static enum lttng_error_code flatten_lttng_events(
1554                 struct lttng_dynamic_pointer_array *events,
1555                 struct lttng_event **flattened_events)
1556 {
1557         enum lttng_error_code ret_code;
1558         int ret, i;
1559         size_t storage_req;
1560         struct lttng_dynamic_buffer local_flattened_events;
1561         int nb_events;
1562
1563         assert(events);
1564         assert(flattened_events);
1565
1566         lttng_dynamic_buffer_init(&local_flattened_events);
1567         nb_events = lttng_dynamic_pointer_array_get_count(events);
1568
1569         ret_code = compute_flattened_size(events, &storage_req);
1570         if (ret_code != LTTNG_OK) {
1571                 goto end;
1572         }
1573
1574         /*
1575          * We must ensure that "local_flattened_events" is never resized so as
1576          * to preserve the validity of the flattened objects.
1577          */
1578         ret = lttng_dynamic_buffer_set_capacity(
1579                         &local_flattened_events, storage_req);
1580         if (ret) {
1581                 ret_code = LTTNG_ERR_NOMEM;
1582                 goto end;
1583         }
1584
1585         /* Start by laying the struct lttng_event */
1586         for (i = 0; i < nb_events; i++) {
1587                 const struct event_list_element *element = (const struct event_list_element *)
1588                                 lttng_dynamic_pointer_array_get_pointer(
1589                                                 events, i);
1590
1591                 if (!element) {
1592                         ret_code = LTTNG_ERR_FATAL;
1593                         goto end;
1594                 }
1595
1596                 ret = lttng_dynamic_buffer_append(&local_flattened_events,
1597                                 element->event, sizeof(struct lttng_event));
1598                 if (ret) {
1599                         ret_code = LTTNG_ERR_NOMEM;
1600                         goto end;
1601                 }
1602         }
1603
1604         for (i = 0; i < nb_events; i++) {
1605                 const struct event_list_element *element = (const struct event_list_element *)
1606                                 lttng_dynamic_pointer_array_get_pointer(events, i);
1607                 struct lttng_event *event = (struct lttng_event *)
1608                         (local_flattened_events.data + (sizeof(struct lttng_event) * i));
1609                 struct lttng_event_extended *event_extended =
1610                         (struct lttng_event_extended *)
1611                                 (local_flattened_events.data + local_flattened_events.size);
1612                 const struct lttng_userspace_probe_location *location = NULL;
1613
1614                 assert(element);
1615
1616                 /* Insert struct lttng_event_extended. */
1617                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1618                                 local_flattened_events.size +
1619                                                 sizeof(*event_extended));
1620                 if (ret) {
1621                         ret_code = LTTNG_ERR_NOMEM;
1622                         goto end;
1623                 }
1624                 event->extended.ptr = event_extended;
1625
1626                 /* Insert filter expression. */
1627                 if (element->filter_expression) {
1628                         const size_t len = strlen(element->filter_expression) + 1;
1629
1630                         event_extended->filter_expression =
1631                                         local_flattened_events.data +
1632                                         local_flattened_events.size;
1633                         ret = lttng_dynamic_buffer_append(
1634                                         &local_flattened_events,
1635                                         element->filter_expression, len);
1636                         if (ret) {
1637                                 ret_code = LTTNG_ERR_NOMEM;
1638                                 goto end;
1639                         }
1640                 }
1641
1642                 /* Insert exclusions. */
1643                 if (element->exclusions) {
1644                         event_extended->exclusions.count =
1645                                         element->exclusions->count;
1646                         event_extended->exclusions.strings =
1647                                         local_flattened_events.data +
1648                                         local_flattened_events.size;
1649
1650                         ret = lttng_dynamic_buffer_append(
1651                                         &local_flattened_events,
1652                                         element->exclusions->names,
1653                                         element->exclusions->count *
1654                                                         LTTNG_SYMBOL_NAME_LEN);
1655                         if (ret) {
1656                                 ret_code = LTTNG_ERR_NOMEM;
1657                                 goto end;
1658                         }
1659                 }
1660
1661                 /* Insert padding to align to 64-bits. */
1662                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1663                                 lttng_align_ceil(local_flattened_events.size,
1664                                                 sizeof(uint64_t)));
1665                 if (ret) {
1666                         ret_code = LTTNG_ERR_NOMEM;
1667                         goto end;
1668                 }
1669
1670                 location = lttng_event_get_userspace_probe_location(
1671                                 element->event);
1672                 if (location) {
1673                         event_extended->probe_location = (struct lttng_userspace_probe_location *)
1674                                         (local_flattened_events.data + local_flattened_events.size);
1675                         ret = lttng_userspace_probe_location_flatten(
1676                                         location, &local_flattened_events);
1677                         if (ret < 0) {
1678                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1679                                 goto end;
1680                         }
1681                 }
1682         }
1683
1684         /* Don't reset local_flattened_events buffer as we return its content. */
1685         *flattened_events = (struct lttng_event *) local_flattened_events.data;
1686         lttng_dynamic_buffer_init(&local_flattened_events);
1687         ret_code = LTTNG_OK;
1688 end:
1689         lttng_dynamic_buffer_reset(&local_flattened_events);
1690         return ret_code;
1691 }
1692
1693 static enum lttng_error_code event_list_create_from_payload(
1694                 struct lttng_payload_view *view,
1695                 unsigned int count,
1696                 struct lttng_dynamic_pointer_array *event_list)
1697 {
1698         enum lttng_error_code ret_code;
1699         int ret;
1700         unsigned int i;
1701         int offset = 0;
1702
1703         assert(view);
1704         assert(event_list);
1705
1706         for (i = 0; i < count; i++) {
1707                 ssize_t event_size;
1708                 struct lttng_payload_view event_view =
1709                                 lttng_payload_view_from_view(view, offset, -1);
1710                 struct event_list_element *element =
1711                                 (struct event_list_element *) zmalloc(sizeof(*element));
1712
1713                 if (!element) {
1714                         ret_code = LTTNG_ERR_NOMEM;
1715                         goto end;
1716                 }
1717
1718                 /*
1719                  * Lifetime and management of the object is now bound to the
1720                  * array.
1721                  */
1722                 ret = lttng_dynamic_pointer_array_add_pointer(
1723                                 event_list, element);
1724                 if (ret) {
1725                         event_list_destructor(element);
1726                         ret_code = LTTNG_ERR_NOMEM;
1727                         goto end;
1728                 }
1729
1730                 /*
1731                  * Bytecode is not transmitted on listing in any case we do not
1732                  * care about it.
1733                  */
1734                 event_size = lttng_event_create_from_payload(&event_view,
1735                                 &element->event,
1736                                 &element->exclusions,
1737                                 &element->filter_expression, NULL);
1738                 if (event_size < 0) {
1739                         ret_code = LTTNG_ERR_INVALID;
1740                         goto end;
1741                 }
1742
1743                 offset += event_size;
1744         }
1745
1746         if (view->buffer.size != offset) {
1747                 ret_code = LTTNG_ERR_INVALID_PROTOCOL;
1748                 goto end;
1749         }
1750
1751         ret_code = LTTNG_OK;
1752
1753 end:
1754         return ret_code;
1755 }
1756
1757 enum lttng_error_code lttng_events_create_and_flatten_from_payload(
1758                 struct lttng_payload_view *payload,
1759                 unsigned int count,
1760                 struct lttng_event **events)
1761 {
1762         enum lttng_error_code ret = LTTNG_OK;
1763         struct lttng_dynamic_pointer_array local_events;
1764
1765         lttng_dynamic_pointer_array_init(&local_events, event_list_destructor);
1766
1767         /* Deserialize the events. */
1768         {
1769                 struct lttng_payload_view events_view =
1770                                 lttng_payload_view_from_view(payload, 0, -1);
1771
1772                 ret = event_list_create_from_payload(
1773                                 &events_view, count, &local_events);
1774                 if (ret != LTTNG_OK) {
1775                         goto end;
1776                 }
1777         }
1778
1779         ret = flatten_lttng_events(&local_events, events);
1780         if (ret != LTTNG_OK) {
1781                 goto end;
1782         }
1783
1784 end:
1785         lttng_dynamic_pointer_array_reset(&local_events);
1786         return ret;
1787 }
1788
1789 static enum lttng_error_code flatten_lttng_event_fields(
1790                 struct lttng_dynamic_pointer_array *event_fields,
1791                 struct lttng_event_field **flattened_event_fields)
1792 {
1793         int ret, i;
1794         enum lttng_error_code ret_code;
1795         size_t storage_req = 0;
1796         struct lttng_dynamic_buffer local_flattened_event_fields;
1797         int nb_event_field;
1798
1799         assert(event_fields);
1800         assert(flattened_event_fields);
1801
1802         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1803         nb_event_field = lttng_dynamic_pointer_array_get_count(event_fields);
1804
1805         /*
1806          * Here even if the event field contains a `struct lttng_event` that
1807          * could contain dynamic data, in reality it is not the case.
1808          * Dynamic data is not present. Here the flattening is mostly a direct
1809          * memcpy. This is less than ideal but this code is still better than
1810          * direct usage of an unpacked lttng_event_field array.
1811          */
1812         storage_req += sizeof(struct lttng_event_field) * nb_event_field;
1813
1814         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1815
1816         /*
1817          * We must ensure that "local_flattened_event_fields" is never resized
1818          * so as to preserve the validity of the flattened objects.
1819          */
1820         ret = lttng_dynamic_buffer_set_capacity(
1821                         &local_flattened_event_fields, storage_req);
1822         if (ret) {
1823                 ret_code = LTTNG_ERR_NOMEM;
1824                 goto end;
1825         }
1826
1827         for (i = 0; i < nb_event_field; i++) {
1828                 const struct lttng_event_field *element =
1829                                 (const struct lttng_event_field *)
1830                                         lttng_dynamic_pointer_array_get_pointer(
1831                                                 event_fields, i);
1832
1833                 if (!element) {
1834                         ret_code = LTTNG_ERR_FATAL;
1835                         goto end;
1836                 }
1837                 ret = lttng_dynamic_buffer_append(&local_flattened_event_fields,
1838                                 element, sizeof(struct lttng_event_field));
1839                 if (ret) {
1840                         ret_code = LTTNG_ERR_NOMEM;
1841                         goto end;
1842                 }
1843         }
1844
1845         /* Don't reset local_flattened_channels buffer as we return its content. */
1846         *flattened_event_fields = (struct lttng_event_field *) local_flattened_event_fields.data;
1847         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1848         ret_code = LTTNG_OK;
1849 end:
1850         lttng_dynamic_buffer_reset(&local_flattened_event_fields);
1851         return ret_code;
1852 }
1853
1854 static enum lttng_error_code event_field_list_create_from_payload(
1855                 struct lttng_payload_view *view,
1856                 unsigned int count,
1857                 struct lttng_dynamic_pointer_array **event_field_list)
1858 {
1859         enum lttng_error_code ret_code;
1860         int ret, offset = 0;
1861         unsigned int i;
1862         struct lttng_dynamic_pointer_array *list = NULL;
1863
1864         assert(view);
1865         assert(event_field_list);
1866
1867         list = (struct lttng_dynamic_pointer_array *) zmalloc(sizeof(*list));
1868         if (!list) {
1869                 ret_code = LTTNG_ERR_NOMEM;
1870                 goto end;
1871         }
1872
1873         lttng_dynamic_pointer_array_init(list, free);
1874
1875         for (i = 0; i < count; i++) {
1876                 ssize_t event_field_size;
1877                 struct lttng_event_field *field = NULL;
1878                 struct lttng_payload_view event_field_view =
1879                                 lttng_payload_view_from_view(view, offset, -1);
1880
1881                 event_field_size = lttng_event_field_create_from_payload(
1882                                 &event_field_view, &field);
1883                 if (event_field_size < 0) {
1884                         ret_code = LTTNG_ERR_INVALID;
1885                         goto end;
1886                 }
1887
1888                 /* Lifetime and management of the object is now bound to the array. */
1889                 ret = lttng_dynamic_pointer_array_add_pointer(list, field);
1890                 if (ret) {
1891                         free(field);
1892                         ret_code = LTTNG_ERR_NOMEM;
1893                         goto end;
1894                 }
1895
1896                 offset += event_field_size;
1897         }
1898
1899         if (view->buffer.size != offset) {
1900                 ret_code = LTTNG_ERR_INVALID;
1901                 goto end;
1902         }
1903
1904         *event_field_list = list;
1905         list = NULL;
1906         ret_code = LTTNG_OK;
1907
1908 end:
1909         if (list) {
1910                 lttng_dynamic_pointer_array_reset(list);
1911                 free(list);
1912         }
1913
1914         return ret_code;
1915 }
1916
1917 enum lttng_error_code lttng_event_fields_create_and_flatten_from_payload(
1918                 struct lttng_payload_view *view,
1919                 unsigned int count,
1920                 struct lttng_event_field **fields)
1921 {
1922         enum lttng_error_code ret_code;
1923         struct lttng_dynamic_pointer_array *local_event_fields = NULL;
1924
1925         ret_code = event_field_list_create_from_payload(
1926                         view, count, &local_event_fields);
1927         if (ret_code != LTTNG_OK) {
1928                 goto end;
1929         }
1930
1931         ret_code = flatten_lttng_event_fields(local_event_fields, fields);
1932         if (ret_code != LTTNG_OK) {
1933                 goto end;
1934         }
1935 end:
1936         if (local_event_fields) {
1937                 lttng_dynamic_pointer_array_reset(local_event_fields);
1938                 free(local_event_fields);
1939         }
1940
1941         return ret_code;
1942 }