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 struct event_list_element {
  24         struct lttng_event *event;
  25         struct lttng_event_exclusion *exclusions;
  26         char *filter_expression;
  27 };
  28
  29 static void event_list_destructor(void *ptr)
  30 {
  31         struct event_list_element *element = (struct event_list_element *) ptr;
  32
  33         free(element->filter_expression);
  34         free(element->exclusions);
  35         lttng_event_destroy(element->event);
  36         free(element);
  37 }
  38
  39 struct lttng_event *lttng_event_copy(const struct lttng_event *event)
  40 {
  41         struct lttng_event *new_event;
  42         struct lttng_event_extended *new_event_extended;
  43
  44         new_event = zmalloc<lttng_event>();
  45         if (!new_event) {
  46                 PERROR("Error allocating event structure");
  47                 goto end;
  48         }
  49
  50         /* Copy the content of the old event. */
  51         memcpy(new_event, event, sizeof(*event));
  52
  53         /*
  54          * We need to create a new extended since the previous pointer is now
  55          * invalid.
  56          */
  57         new_event_extended = zmalloc<lttng_event_extended>();
  58         if (!new_event_extended) {
  59                 PERROR("Error allocating event extended structure");
  60                 goto error;
  61         }
  62
  63         new_event->extended.ptr = new_event_extended;
  64 end:
  65         return new_event;
  66 error:
  67         free(new_event);
  68         new_event = NULL;
  69         goto end;
  70 }
  71
  72 static int lttng_event_probe_attr_serialize(
  73                 const struct lttng_event_probe_attr *probe,
  74                 struct lttng_payload *payload)
  75 {
  76         int ret;
  77         size_t symbol_name_len;
  78         struct lttng_event_probe_attr_comm comm = {};
  79
  80         symbol_name_len = lttng_strnlen(
  81                         probe->symbol_name, sizeof(probe->symbol_name));
  82         if (symbol_name_len == sizeof(probe->symbol_name)) {
  83                 /* Not null-termintated. */
  84                 ret = -1;
  85                 goto end;
  86         }
  87
  88         /* Include the null terminator. */
  89         symbol_name_len += 1;
  90
  91         comm.symbol_name_len = (uint32_t) symbol_name_len;
  92         comm.addr = probe->addr;
  93         comm.offset = probe->addr;
  94
  95         ret = lttng_dynamic_buffer_append(
  96                         &payload->buffer, &comm, sizeof(comm));
  97         if (ret < 0) {
  98                 ret = -1;
  99                 goto end;
 100         }
 101
 102         ret = lttng_dynamic_buffer_append(
 103                         &payload->buffer, probe->symbol_name, symbol_name_len);
 104 end:
 105         return ret;
 106 }
 107
 108 static int lttng_event_function_attr_serialize(
 109                 const struct lttng_event_function_attr *function,
 110                 struct lttng_payload *payload)
 111 {
 112         int ret;
 113         size_t symbol_name_len;
 114         struct lttng_event_function_attr_comm comm = { 0 };
 115
 116         symbol_name_len = lttng_strnlen(
 117                         function->symbol_name, sizeof(function->symbol_name));
 118         if (symbol_name_len == sizeof(function->symbol_name)) {
 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 = zmalloc<lttng_event_probe_attr>();
 161         if (local_attr == NULL) {
 162                 ret = -1;
 163                 goto end;
 164         }
 165
 166         local_attr->addr = comm->addr;
 167         local_attr->offset = comm->offset;
 168
 169         {
 170                 const char *name;
 171                 struct lttng_payload_view name_view =
 172                                 lttng_payload_view_from_view(view, offset,
 173                                                 comm->symbol_name_len);
 174
 175                 if (!lttng_payload_view_is_valid(&name_view)) {
 176                         ret = -1;
 177                         goto end;
 178                 }
 179
 180                 name = name_view.buffer.data;
 181
 182                 if (!lttng_buffer_view_contains_string(&name_view.buffer, name,
 183                                     comm->symbol_name_len)) {
 184                         ret = -1;
 185                         goto end;
 186                 }
 187
 188                 ret = lttng_strncpy(local_attr->symbol_name, name,
 189                                 sizeof(local_attr->symbol_name));
 190                 if (ret) {
 191                         ret = -1;
 192                         goto end;
 193                 }
 194
 195                 offset += comm->symbol_name_len;
 196         }
 197
 198         *probe_attr = local_attr;
 199         local_attr = NULL;
 200         ret = offset;
 201 end:
 202         free(local_attr);
 203         return ret;
 204 }
 205
 206 static ssize_t lttng_event_function_attr_create_from_payload(
 207                 struct lttng_payload_view *view,
 208                 struct lttng_event_function_attr **function_attr)
 209 {
 210         ssize_t ret, offset = 0;
 211         const struct lttng_event_function_attr_comm *comm;
 212         struct lttng_event_function_attr *local_attr = NULL;
 213         struct lttng_payload_view comm_view = lttng_payload_view_from_view(
 214                         view, offset, sizeof(*comm));
 215
 216         if (!lttng_payload_view_is_valid(&comm_view)) {
 217                 ret = -1;
 218                 goto end;
 219         }
 220
 221         comm = (typeof(comm)) view->buffer.data;
 222         offset += sizeof(*comm);
 223
 224         local_attr = zmalloc<lttng_event_function_attr>();
 225         if (local_attr == NULL) {
 226                 ret = -1;
 227                 goto end;
 228         }
 229
 230         {
 231                 const char *name;
 232                 struct lttng_payload_view name_view =
 233                                 lttng_payload_view_from_view(view, offset,
 234                                                 comm->symbol_name_len);
 235
 236                 if (!lttng_payload_view_is_valid(&name_view)) {
 237                         ret = -1;
 238                         goto end;
 239                 }
 240
 241                 name = name_view.buffer.data;
 242
 243                 if (!lttng_buffer_view_contains_string(&name_view.buffer, name,
 244                                     comm->symbol_name_len)) {
 245                         ret = -1;
 246                         goto end;
 247                 }
 248
 249                 ret = lttng_strncpy(local_attr->symbol_name, name,
 250                                 sizeof(local_attr->symbol_name));
 251                 if (ret) {
 252                         ret = -1;
 253                         goto end;
 254                 }
 255
 256                 offset += comm->symbol_name_len;
 257         }
 258
 259         *function_attr = local_attr;
 260         local_attr = NULL;
 261         ret = offset;
 262 end:
 263         free(local_attr);
 264         return ret;
 265 }
 266
 267 static ssize_t lttng_event_exclusions_create_from_payload(
 268                 struct lttng_payload_view *view,
 269                 uint32_t count,
 270                 struct lttng_event_exclusion **exclusions)
 271 {
 272         ssize_t ret, offset = 0;
 273         const size_t size = (count * LTTNG_SYMBOL_NAME_LEN);
 274         uint32_t i;
 275         const struct lttng_event_exclusion_comm *comm;
 276         struct lttng_event_exclusion *local_exclusions;
 277
 278         local_exclusions = zmalloc<lttng_event_exclusion>(
 279                         sizeof(struct lttng_event_exclusion) + size);
 280         if (!local_exclusions) {
 281                 ret = -1;
 282                 goto end;
 283         }
 284
 285         local_exclusions->count = count;
 286
 287         for (i = 0; i < count; i++) {
 288                 const char *string;
 289                 struct lttng_buffer_view string_view;
 290                 const struct lttng_buffer_view comm_view =
 291                                 lttng_buffer_view_from_view(&view->buffer,
 292                                                 offset, sizeof(*comm));
 293
 294                 if (!lttng_buffer_view_is_valid(&comm_view)) {
 295                         ret = -1;
 296                         goto end;
 297                 }
 298
 299                 comm = (typeof(comm)) comm_view.data;
 300                 offset += sizeof(*comm);
 301
 302                 string_view = lttng_buffer_view_from_view(
 303                                 &view->buffer, offset, comm->len);
 304
 305                 if (!lttng_buffer_view_is_valid(&string_view)) {
 306                         ret = -1;
 307                         goto end;
 308                 }
 309
 310                 string = string_view.data;
 311
 312                 if (!lttng_buffer_view_contains_string(
 313                                     &string_view, string, comm->len)) {
 314                         ret = -1;
 315                         goto end;
 316                 }
 317
 318                 ret = lttng_strncpy(LTTNG_EVENT_EXCLUSION_NAME_AT(local_exclusions, i), string,
 319                                 sizeof(LTTNG_EVENT_EXCLUSION_NAME_AT(local_exclusions, i)));
 320                 if (ret) {
 321                         ret = -1;
 322                         goto end;
 323                 }
 324
 325                 offset += comm->len;
 326         }
 327
 328         *exclusions = local_exclusions;
 329         local_exclusions = NULL;
 330         ret = offset;
 331 end:
 332         free(local_exclusions);
 333         return ret;
 334 }
 335
 336 ssize_t lttng_event_create_from_payload(struct lttng_payload_view *view,
 337                 struct lttng_event **out_event,
 338                 struct lttng_event_exclusion **out_exclusion,
 339                 char **out_filter_expression,
 340                 struct lttng_bytecode **out_bytecode)
 341 {
 342         ssize_t ret, offset = 0;
 343         struct lttng_event *local_event = NULL;
 344         struct lttng_event_exclusion *local_exclusions = NULL;
 345         struct lttng_bytecode *local_bytecode = NULL;
 346         char *local_filter_expression = NULL;
 347         const struct lttng_event_comm *event_comm;
 348         struct lttng_event_function_attr *local_function_attr = NULL;
 349         struct lttng_event_probe_attr *local_probe_attr = NULL;
 350         struct lttng_userspace_probe_location *local_userspace_probe_location =
 351                         NULL;
 352
 353         /*
 354          * Only event is obligatory, the other output argument are optional and
 355          * depends on what the caller is interested in.
 356          */
 357         assert(out_event);
 358         assert(view);
 359
 360         {
 361                 struct lttng_payload_view comm_view =
 362                                 lttng_payload_view_from_view(view, offset,
 363                                                 sizeof(*event_comm));
 364
 365                 if (!lttng_payload_view_is_valid(&comm_view)) {
 366                         ret = -1;
 367                         goto end;
 368                 }
 369
 370                 /* lttng_event_comm header */
 371                 event_comm = (typeof(event_comm)) comm_view.buffer.data;
 372                 offset += sizeof(*event_comm);
 373         }
 374
 375         local_event = lttng_event_create();
 376         if (local_event == NULL) {
 377                 ret = -1;
 378                 goto end;
 379         }
 380
 381         local_event->type = (enum lttng_event_type) event_comm->event_type;
 382         local_event->loglevel_type = (enum lttng_loglevel_type) event_comm->loglevel_type;
 383         local_event->loglevel = event_comm->loglevel;
 384         local_event->enabled = event_comm->enabled;
 385         local_event->pid = event_comm->pid;
 386         local_event->flags = (enum lttng_event_flag) event_comm->flags;
 387
 388         {
 389                 const char *name;
 390                 const struct lttng_buffer_view name_view =
 391                                 lttng_buffer_view_from_view(&view->buffer,
 392                                                 offset, event_comm->name_len);
 393
 394                 if (!lttng_buffer_view_is_valid(&name_view)) {
 395                         ret = -1;
 396                         goto end;
 397                 }
 398
 399                 name = (const char *) name_view.data;
 400
 401                 if (!lttng_buffer_view_contains_string(
 402                                     &name_view, name, event_comm->name_len)) {
 403                         ret = -1;
 404                         goto end;
 405                 }
 406
 407                 ret = lttng_strncpy(local_event->name, name,
 408                                 sizeof(local_event->name));
 409                 if (ret) {
 410                         ret = -1;
 411                         goto end;
 412                 }
 413
 414                 offset += event_comm->name_len;
 415         }
 416
 417         /* Exclusions */
 418         if (event_comm->exclusion_count == 0) {
 419                 goto deserialize_filter_expression;
 420         }
 421
 422         {
 423                 struct lttng_payload_view exclusions_view =
 424                                 lttng_payload_view_from_view(
 425                                                 view, offset, -1);
 426
 427                 if (!lttng_payload_view_is_valid(&exclusions_view)) {
 428                         ret = -1;
 429                         goto end;
 430                 }
 431
 432                 ret = lttng_event_exclusions_create_from_payload(&exclusions_view,
 433                                 event_comm->exclusion_count, &local_exclusions);
 434                 if (ret < 0) {
 435                         ret = -1;
 436                         goto end;
 437                 }
 438                 offset += ret;
 439
 440                 local_event->exclusion = 1;
 441         }
 442
 443 deserialize_filter_expression:
 444
 445         if (event_comm->filter_expression_len == 0) {
 446                 if (event_comm->bytecode_len != 0) {
 447                         /*
 448                          * This is an invalid event payload.
 449                          *
 450                          * Filter expression without bytecode is possible but
 451                          * not the other way around.
 452                          * */
 453                         ret = -1;
 454                         goto end;
 455                 }
 456                 goto deserialize_event_type_payload;
 457         }
 458
 459         {
 460                 const char *filter_expression_buffer;
 461                 struct lttng_buffer_view filter_expression_view =
 462                                 lttng_buffer_view_from_view(&view->buffer, offset,
 463                                                 event_comm->filter_expression_len);
 464
 465                 if (!lttng_buffer_view_is_valid(&filter_expression_view)) {
 466                         ret = -1;
 467                         goto end;
 468                 }
 469
 470                 filter_expression_buffer = filter_expression_view.data;
 471
 472                 if (!lttng_buffer_view_contains_string(&filter_expression_view,
 473                                     filter_expression_buffer,
 474                                     event_comm->filter_expression_len)) {
 475                         ret = -1;
 476                         goto end;
 477                 }
 478
 479                 local_filter_expression = lttng_strndup(
 480                                 filter_expression_buffer,
 481                                 event_comm->filter_expression_len);
 482                 if (!local_filter_expression) {
 483                         ret = -1;
 484                         goto end;
 485                 }
 486
 487                 local_event->filter = 1;
 488
 489                 offset += event_comm->filter_expression_len;
 490         }
 491
 492         if (event_comm->bytecode_len == 0) {
 493                 /*
 494                  * Filter expression can be present but without bytecode
 495                  * when dealing with event listing.
 496                  */
 497                 goto deserialize_event_type_payload;
 498         }
 499
 500         /* Bytecode */
 501         {
 502                 struct lttng_payload_view bytecode_view =
 503                                 lttng_payload_view_from_view(view, offset,
 504                                                 event_comm->bytecode_len);
 505
 506                 if (!lttng_payload_view_is_valid(&bytecode_view)) {
 507                         ret = -1;
 508                         goto end;
 509                 }
 510
 511                 local_bytecode = zmalloc<lttng_bytecode>(event_comm->bytecode_len);
 512                 if (!local_bytecode) {
 513                         ret = -1;
 514                         goto end;
 515                 }
 516
 517                 memcpy(local_bytecode, bytecode_view.buffer.data,
 518                                 event_comm->bytecode_len);
 519                 if ((local_bytecode->len + sizeof(*local_bytecode)) !=
 520                                 event_comm->bytecode_len) {
 521                         ret = -1;
 522                         goto end;
 523                 }
 524
 525                 offset += event_comm->bytecode_len;
 526         }
 527
 528 deserialize_event_type_payload:
 529         /* Event type specific payload */
 530         switch (local_event->type) {
 531         case LTTNG_EVENT_FUNCTION:
 532                 /* Fallthrough */
 533         case LTTNG_EVENT_PROBE:
 534         {
 535                 struct lttng_payload_view probe_attr_view =
 536                                 lttng_payload_view_from_view(view, offset,
 537                                                 event_comm->lttng_event_probe_attr_len);
 538
 539                 if (event_comm->lttng_event_probe_attr_len == 0) {
 540                         ret = -1;
 541                         goto end;
 542                 }
 543
 544                 if (!lttng_payload_view_is_valid(&probe_attr_view)) {
 545                         ret = -1;
 546                         goto end;
 547                 }
 548
 549                 ret = lttng_event_probe_attr_create_from_payload(
 550                                 &probe_attr_view, &local_probe_attr);
 551                 if (ret < 0 || ret != event_comm->lttng_event_probe_attr_len) {
 552                         ret = -1;
 553                         goto end;
 554                 }
 555
 556                 /* Copy to the local event. */
 557                 memcpy(&local_event->attr.probe, local_probe_attr,
 558                                 sizeof(local_event->attr.probe));
 559
 560                 offset += ret;
 561                 break;
 562         }
 563         case LTTNG_EVENT_FUNCTION_ENTRY:
 564         {
 565                 struct lttng_payload_view function_attr_view =
 566                                 lttng_payload_view_from_view(view, offset,
 567                                                 event_comm->lttng_event_function_attr_len);
 568
 569                 if (event_comm->lttng_event_function_attr_len == 0) {
 570                         ret = -1;
 571                         goto end;
 572                 }
 573
 574                 if (!lttng_payload_view_is_valid(&function_attr_view)) {
 575                         ret = -1;
 576                         goto end;
 577                 }
 578
 579                 ret = lttng_event_function_attr_create_from_payload(
 580                                 &function_attr_view, &local_function_attr);
 581                 if (ret < 0 || ret != event_comm->lttng_event_function_attr_len) {
 582                         ret = -1;
 583                         goto end;
 584                 }
 585
 586                 /* Copy to the local event. */
 587                 memcpy(&local_event->attr.ftrace, local_function_attr,
 588                                 sizeof(local_event->attr.ftrace));
 589
 590                 offset += ret;
 591
 592                 break;
 593         }
 594         case LTTNG_EVENT_USERSPACE_PROBE:
 595         {
 596                 struct lttng_payload_view userspace_probe_location_view =
 597                                 lttng_payload_view_from_view(view, offset,
 598                                                 event_comm->userspace_probe_location_len);
 599
 600                 if (event_comm->userspace_probe_location_len == 0) {
 601                         ret = -1;
 602                         goto end;
 603                 }
 604
 605                 if (!lttng_payload_view_is_valid(
 606                                     &userspace_probe_location_view)) {
 607                         ret = -1;
 608                         goto end;
 609                 }
 610
 611                 ret = lttng_userspace_probe_location_create_from_payload(
 612                                 &userspace_probe_location_view,
 613                                 &local_userspace_probe_location);
 614                 if (ret < 0) {
 615                         WARN("Failed to create a userspace probe location from the received buffer");
 616                         ret = -1;
 617                         goto end;
 618                 }
 619
 620                 if (ret != event_comm->userspace_probe_location_len) {
 621                         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);
 622                         ret = -1;
 623                         goto end;
 624                 }
 625
 626                 /* Attach the probe location to the event. */
 627                 ret = lttng_event_set_userspace_probe_location(
 628                                 local_event, local_userspace_probe_location);
 629                 if (ret) {
 630                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 631                         goto end;
 632                 }
 633
 634                 /*
 635                  * Userspace probe location object ownership transfered to the
 636                  * event object.
 637                  */
 638                 local_userspace_probe_location = NULL;
 639                 offset += event_comm->userspace_probe_location_len;
 640                 break;
 641         }
 642         case LTTNG_EVENT_TRACEPOINT:
 643                 /* Fallthrough */
 644         case LTTNG_EVENT_ALL:
 645                 /* Fallthrough */
 646         case LTTNG_EVENT_SYSCALL:
 647                 /* Fallthrough */
 648         case LTTNG_EVENT_NOOP:
 649                 /* Nothing to do here */
 650                 break;
 651         default:
 652                 ret = LTTNG_ERR_UND;
 653                 goto end;
 654                 break;
 655         }
 656
 657         /* Transfer ownership to the caller. */
 658         *out_event = local_event;
 659         local_event = NULL;
 660
 661         if (out_bytecode) {
 662                 *out_bytecode = local_bytecode;
 663                 local_bytecode = NULL;
 664         }
 665
 666         if (out_exclusion) {
 667                 *out_exclusion = local_exclusions;
 668                 local_exclusions = NULL;
 669         }
 670
 671         if (out_filter_expression) {
 672                 *out_filter_expression = local_filter_expression;
 673                 local_filter_expression = NULL;
 674         }
 675
 676         ret = offset;
 677 end:
 678         lttng_event_destroy(local_event);
 679         lttng_userspace_probe_location_destroy(local_userspace_probe_location);
 680         free(local_filter_expression);
 681         free(local_exclusions);
 682         free(local_bytecode);
 683         free(local_function_attr);
 684         free(local_probe_attr);
 685         return ret;
 686 }
 687
 688 int lttng_event_serialize(const struct lttng_event *event,
 689                 unsigned int exclusion_count,
 690                 char **exclusion_list,
 691                 char *filter_expression,
 692                 size_t bytecode_len,
 693                 struct lttng_bytecode *bytecode,
 694                 struct lttng_payload *payload)
 695 {
 696         int ret;
 697         unsigned int i;
 698         size_t header_offset, size_before_payload;
 699         size_t name_len;
 700         struct lttng_event_comm event_comm = {};
 701         struct lttng_event_comm *header;
 702
 703         assert(event);
 704         assert(payload);
 705         assert(exclusion_count == 0 || exclusion_list);
 706
 707         /* Save the header location for later in-place header update. */
 708         header_offset = payload->buffer.size;
 709
 710         name_len = lttng_strnlen(event->name, sizeof(event->name));
 711         if (name_len == sizeof(event->name)) {
 712                 /* Event name is not NULL-terminated. */
 713                 ret = -1;
 714                 goto end;
 715         }
 716
 717         /* Add null termination. */
 718         name_len += 1;
 719
 720         if (exclusion_count > UINT32_MAX) {
 721                 /* Possible overflow. */
 722                 ret = -1;
 723                 goto end;
 724         }
 725
 726         if (bytecode_len > UINT32_MAX) {
 727                 /* Possible overflow. */
 728                 ret = -1;
 729                 goto end;
 730         }
 731
 732         event_comm.name_len = (uint32_t) name_len;
 733         event_comm.event_type = (int8_t) event->type;
 734         event_comm.loglevel_type = (int8_t) event->loglevel_type;
 735         event_comm.loglevel = (int32_t) event->loglevel;
 736         event_comm.enabled = (int8_t) event->enabled;
 737         event_comm.pid = (int32_t) event->pid;
 738         event_comm.exclusion_count = (uint32_t) exclusion_count;
 739         event_comm.bytecode_len = (uint32_t) bytecode_len;
 740         event_comm.flags = (int32_t) event->flags;
 741
 742         if (filter_expression) {
 743                 event_comm.filter_expression_len =
 744                                 strlen(filter_expression) + 1;
 745         }
 746
 747         /* Header */
 748         ret = lttng_dynamic_buffer_append(
 749                         &payload->buffer, &event_comm, sizeof(event_comm));
 750         if (ret) {
 751                 goto end;
 752         }
 753
 754         /* Event name */
 755         ret = lttng_dynamic_buffer_append(
 756                         &payload->buffer, event->name, name_len);
 757         if (ret) {
 758                 goto end;
 759         }
 760
 761         /* Exclusions */
 762         for (i = 0; i < exclusion_count; i++) {
 763                 const size_t exclusion_len = lttng_strnlen(
 764                                 *(exclusion_list + i), LTTNG_SYMBOL_NAME_LEN);
 765                 const struct lttng_event_exclusion_comm exclusion_header = {
 766                         .len = (uint32_t) exclusion_len + 1,
 767                 };
 768
 769                 if (exclusion_len == LTTNG_SYMBOL_NAME_LEN) {
 770                         /* Exclusion is not NULL-terminated. */
 771                         ret = -1;
 772                         goto end;
 773                 }
 774
 775                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 776                                 &exclusion_header, sizeof(exclusion_header));
 777                 if (ret) {
 778                         goto end;
 779                 }
 780
 781                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 782                                 *(exclusion_list + i), exclusion_len + 1);
 783                 if (ret) {
 784                         goto end;
 785                 }
 786         }
 787
 788         /* Filter expression and its bytecode */
 789         if (filter_expression) {
 790                 ret = lttng_dynamic_buffer_append(&payload->buffer,
 791                                 filter_expression,
 792                                 event_comm.filter_expression_len);
 793                 if (ret) {
 794                         goto end;
 795                 }
 796
 797                 /*
 798                  * Bytecode can be absent when we serialize to the client
 799                  * for listing.
 800                  */
 801                 if (bytecode) {
 802                         ret = lttng_dynamic_buffer_append(&payload->buffer,
 803                                         bytecode, bytecode_len);
 804                         if (ret) {
 805                                 goto end;
 806                         }
 807                 }
 808         }
 809
 810         size_before_payload = payload->buffer.size;
 811
 812         /* Event type specific payload */
 813         switch (event->type) {
 814         case LTTNG_EVENT_FUNCTION:
 815                 /* Fallthrough */
 816         case LTTNG_EVENT_PROBE:
 817                 ret = lttng_event_probe_attr_serialize(&event->attr.probe, payload);
 818                 if (ret) {
 819                         ret = -1;
 820                         goto end;
 821                 }
 822
 823                 header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 824                                                       header_offset);
 825                 header->lttng_event_probe_attr_len =
 826                                 payload->buffer.size - size_before_payload;
 827
 828                 break;
 829         case LTTNG_EVENT_FUNCTION_ENTRY:
 830                 ret = lttng_event_function_attr_serialize(
 831                                 &event->attr.ftrace, payload);
 832                 if (ret) {
 833                         ret = -1;
 834                         goto end;
 835                 }
 836
 837                 /* Update the lttng_event_function_attr len. */
 838                 header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 839                                                       header_offset);
 840                 header->lttng_event_function_attr_len =
 841                                 payload->buffer.size - size_before_payload;
 842
 843                 break;
 844         case LTTNG_EVENT_USERSPACE_PROBE:
 845         {
 846                 const struct lttng_event_extended *ev_ext =
 847                                 (const struct lttng_event_extended *)
 848                                                 event->extended.ptr;
 849
 850                 assert(event->extended.ptr);
 851                 assert(ev_ext->probe_location);
 852
 853                 size_before_payload = payload->buffer.size;
 854                 if (ev_ext->probe_location) {
 855                         /*
 856                          * lttng_userspace_probe_location_serialize returns the
 857                          * number of bytes that were appended to the buffer.
 858                          */
 859                         ret = lttng_userspace_probe_location_serialize(
 860                                         ev_ext->probe_location, payload);
 861                         if (ret < 0) {
 862                                 goto end;
 863                         }
 864
 865                         ret = 0;
 866
 867                         /* Update the userspace probe location len. */
 868                         header = (struct lttng_event_comm *) ((char *) payload->buffer.data +
 869                                                               header_offset);
 870                         header->userspace_probe_location_len =
 871                                         payload->buffer.size - size_before_payload;
 872                 }
 873                 break;
 874         }
 875         case LTTNG_EVENT_TRACEPOINT:
 876                 /* Fallthrough */
 877         case LTTNG_EVENT_ALL:
 878                 /* Fallthrough */
 879         default:
 880                 /* Nothing to do here. */
 881                 break;
 882         }
 883
 884 end:
 885         return ret;
 886 }
 887
 888 static ssize_t lttng_event_context_app_populate_from_payload(
 889                 const struct lttng_payload_view *view,
 890                 struct lttng_event_context *event_ctx)
 891 {
 892         ssize_t ret, offset = 0;
 893         const struct lttng_event_context_app_comm *comm;
 894         char *provider_name = NULL, *context_name = NULL;
 895         size_t provider_name_len, context_name_len;
 896         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
 897                         &view->buffer, offset, sizeof(*comm));
 898
 899         assert(event_ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
 900
 901         if (!lttng_buffer_view_is_valid(&comm_view)) {
 902                 ret = -1;
 903                 goto end;
 904         }
 905
 906         comm = (typeof(comm)) comm_view.data;
 907         offset += sizeof(*comm);
 908
 909         provider_name_len = comm->provider_name_len;
 910         context_name_len = comm->ctx_name_len;
 911
 912         if (provider_name_len == 0 || context_name_len == 0) {
 913                 /*
 914                  * Application provider and context names MUST
 915                  * be provided.
 916                  */
 917                 ret = -1;
 918                 goto end;
 919         }
 920
 921         {
 922                 const char *name;
 923                 const struct lttng_buffer_view provider_name_view =
 924                                 lttng_buffer_view_from_view(&view->buffer,
 925                                                 offset,
 926                                                 provider_name_len);
 927
 928                 if (!lttng_buffer_view_is_valid(&provider_name_view)) {
 929                         ret = -1;
 930                         goto end;
 931                 }
 932
 933                 name = provider_name_view.data;
 934
 935                 if (!lttng_buffer_view_contains_string(&provider_name_view,
 936                                 name, provider_name_len)) {
 937                         ret = -1;
 938                         goto end;
 939                 }
 940
 941                 provider_name = lttng_strndup(name, provider_name_len);
 942                 if (!provider_name) {
 943                         ret = -1;
 944                         goto end;
 945                 }
 946
 947                 offset += provider_name_len;
 948         }
 949
 950         {
 951                 const char *name;
 952                 const struct lttng_buffer_view context_name_view =
 953                                 lttng_buffer_view_from_view(
 954                                                 &view->buffer, offset,
 955                                                 context_name_len);
 956
 957                 if (!lttng_buffer_view_is_valid(&context_name_view)) {
 958                         ret = -1;
 959                         goto end;
 960                 }
 961
 962                 name = context_name_view.data;
 963
 964                 if (!lttng_buffer_view_contains_string(&context_name_view, name,
 965                                     context_name_len)) {
 966                         ret = -1;
 967                         goto end;
 968                 }
 969
 970                 context_name = lttng_strndup(name, context_name_len);
 971                 if (!context_name) {
 972                         ret = -1;
 973                         goto end;
 974                 }
 975
 976                 offset += context_name_len;
 977         }
 978
 979         /* Transfer ownership of the strings */
 980         event_ctx->u.app_ctx.provider_name = provider_name;
 981         event_ctx->u.app_ctx.ctx_name = context_name;
 982         provider_name = NULL;
 983         context_name = NULL;
 984
 985         ret = offset;
 986 end:
 987         free(provider_name);
 988         free(context_name);
 989
 990         return ret;
 991 }
 992
 993 static ssize_t lttng_event_context_perf_counter_populate_from_payload(
 994                 const struct lttng_payload_view *view,
 995                 struct lttng_event_context *event_ctx)
 996 {
 997         int ret;
 998         ssize_t consumed, offset = 0;
 999         const struct lttng_event_context_perf_counter_comm *comm;
1000         size_t name_len;
1001         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
1002                         &view->buffer, offset, sizeof(*comm));
1003
1004         assert(event_ctx->ctx == LTTNG_EVENT_CONTEXT_PERF_COUNTER ||
1005                         event_ctx->ctx ==
1006                                         LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER ||
1007                         event_ctx->ctx == LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER);
1008
1009         if (!lttng_buffer_view_is_valid(&comm_view)) {
1010                 consumed = -1;
1011                 goto end;
1012         }
1013
1014         comm = (typeof(comm)) comm_view.data;
1015         offset += sizeof(*comm);
1016
1017         name_len = comm->name_len;
1018
1019         {
1020                 const char *name;
1021                 const struct lttng_buffer_view provider_name_view =
1022                                 lttng_buffer_view_from_view(
1023                                                 &view->buffer, offset,
1024                                                 name_len);
1025
1026                 if (!lttng_buffer_view_is_valid(&provider_name_view)) {
1027                         consumed = -1;
1028                         goto end;
1029                 }
1030
1031                 name = provider_name_view.data;
1032
1033                 if (!lttng_buffer_view_contains_string(
1034                                     &provider_name_view, name, name_len)) {
1035                         consumed = -1;
1036                         goto end;
1037                 }
1038
1039                 ret = lttng_strncpy(event_ctx->u.perf_counter.name, name,
1040                                 sizeof(event_ctx->u.perf_counter.name));
1041                 if (ret) {
1042                         consumed = -1;
1043                         goto end;
1044                 }
1045                 offset += name_len;
1046         }
1047
1048         event_ctx->u.perf_counter.config = comm->config;
1049         event_ctx->u.perf_counter.type = comm->type;
1050
1051         consumed = offset;
1052
1053 end:
1054         return consumed;
1055 }
1056
1057 ssize_t lttng_event_context_create_from_payload(
1058                 struct lttng_payload_view *view,
1059                 struct lttng_event_context **event_ctx)
1060 {
1061         ssize_t ret, offset = 0;
1062         const struct lttng_event_context_comm *comm;
1063         struct lttng_event_context *local_context = NULL;
1064         struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
1065                         &view->buffer, offset, sizeof(*comm));
1066
1067         assert(event_ctx);
1068         assert(view);
1069
1070         if (!lttng_buffer_view_is_valid(&comm_view)) {
1071                 ret = -1;
1072                 goto end;
1073         }
1074
1075         comm = (typeof(comm)) comm_view.data;
1076         offset += sizeof(*comm);
1077
1078         local_context = zmalloc<lttng_event_context>();
1079         if (!local_context) {
1080                 ret = -1;
1081                 goto end;
1082         }
1083
1084         local_context->ctx = (lttng_event_context_type) comm->type;
1085
1086         {
1087                 struct lttng_payload_view subtype_view =
1088                                 lttng_payload_view_from_view(view, offset, -1);
1089
1090                 switch (local_context->ctx) {
1091                 case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1092                         ret = lttng_event_context_app_populate_from_payload(
1093                                         &subtype_view, local_context);
1094                         break;
1095                 case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1096                 case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1097                 case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1098                         ret = lttng_event_context_perf_counter_populate_from_payload(
1099                                         &subtype_view, local_context);
1100                         break;
1101                 default:
1102                         /* Nothing else to deserialize. */
1103                         ret = 0;
1104                         break;
1105                 }
1106         }
1107
1108         if (ret < 0) {
1109                 goto end;
1110         }
1111
1112         offset += ret;
1113
1114         *event_ctx = local_context;
1115         local_context = NULL;
1116         ret = offset;
1117
1118 end:
1119         free(local_context);
1120         return ret;
1121 }
1122
1123 static int lttng_event_context_app_serialize(
1124                 struct lttng_event_context *context,
1125                 struct lttng_payload *payload)
1126 {
1127         int ret;
1128         struct lttng_event_context_app_comm comm = {};
1129         size_t provider_len, ctx_len;
1130         const char *provider_name;
1131         const char *ctx_name;
1132
1133         assert(payload);
1134         assert(context);
1135         assert(context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
1136
1137         provider_name = context->u.app_ctx.provider_name;
1138         ctx_name = context->u.app_ctx.ctx_name;
1139
1140         if (!provider_name || !ctx_name) {
1141                 ret = -LTTNG_ERR_INVALID;
1142                 goto end;
1143         }
1144
1145         provider_len = strlen(provider_name);
1146         if (provider_len == 0) {
1147                 ret = -LTTNG_ERR_INVALID;
1148                 goto end;
1149         }
1150
1151         /* Include the null terminator. */
1152         provider_len += 1;
1153         comm.provider_name_len = provider_len;
1154
1155         ctx_len = strlen(ctx_name);
1156         if (ctx_len == 0) {
1157                 ret = -LTTNG_ERR_INVALID;
1158                 goto end;
1159         }
1160
1161         /* Include the null terminator. */
1162         ctx_len += 1;
1163         comm.ctx_name_len = ctx_len;
1164
1165         /* Header */
1166         ret = lttng_dynamic_buffer_append(&payload->buffer, &comm,
1167                         sizeof(comm));
1168         if (ret) {
1169                 ret = -1;
1170                 goto end;
1171         }
1172
1173         ret = lttng_dynamic_buffer_append(&payload->buffer, provider_name,
1174                         provider_len);
1175         if (ret) {
1176                 ret = -1;
1177                 goto end;
1178         }
1179
1180         ret = lttng_dynamic_buffer_append(&payload->buffer, ctx_name,
1181                         ctx_len);
1182         if (ret) {
1183                 ret = -1;
1184                 goto end;
1185         }
1186
1187 end:
1188         return ret;
1189 }
1190
1191 static int lttng_event_context_perf_counter_serialize(
1192                 struct lttng_event_perf_counter_ctx *context,
1193                 struct lttng_payload *payload)
1194 {
1195         int ret;
1196         struct lttng_event_context_perf_counter_comm comm = {};
1197
1198         assert(payload);
1199         assert(context);
1200
1201         comm.config = context->config;
1202         comm.type = context->type;
1203         comm.name_len = lttng_strnlen(context->name, sizeof(context->name));
1204
1205         if (comm.name_len == sizeof(context->name)) {
1206                 ret = -1;
1207                 goto end;
1208         }
1209
1210         /* Include the null terminator. */
1211         comm.name_len += 1;
1212
1213         /* Header */
1214         ret = lttng_dynamic_buffer_append(&payload->buffer, &comm,
1215                         sizeof(comm));
1216         if (ret) {
1217                 ret = -1;
1218                 goto end;
1219         }
1220
1221         ret = lttng_dynamic_buffer_append(&payload->buffer, context->name,
1222                         comm.name_len);
1223         if (ret) {
1224                 ret = -1;
1225                 goto end;
1226         }
1227
1228 end:
1229         return ret;
1230 }
1231
1232 int lttng_event_context_serialize(struct lttng_event_context *context,
1233                 struct lttng_payload *payload)
1234 {
1235         int ret;
1236         struct lttng_event_context_comm context_comm = { 0 };
1237
1238         assert(context);
1239         assert(payload);
1240
1241         context_comm.type = (uint32_t) context->ctx;
1242
1243         /* Header */
1244         ret = lttng_dynamic_buffer_append(
1245                         &payload->buffer, &context_comm, sizeof(context_comm));
1246         if (ret) {
1247                 goto end;
1248         }
1249
1250         switch (context->ctx) {
1251         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1252                 ret = lttng_event_context_app_serialize(context, payload);
1253                 break;
1254         case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1255         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1256         case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1257                 ret = lttng_event_context_perf_counter_serialize(
1258                                 &context->u.perf_counter, payload);
1259                 break;
1260         default:
1261                 /* Nothing else to serialize. */
1262                 break;
1263         }
1264
1265         if (ret) {
1266                 goto end;
1267         }
1268
1269 end:
1270         return ret;
1271 }
1272
1273 void lttng_event_context_destroy(struct lttng_event_context *context)
1274 {
1275         if (!context) {
1276                 return;
1277         }
1278
1279         if (context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
1280                 free(context->u.app_ctx.provider_name);
1281                 free(context->u.app_ctx.ctx_name);
1282         }
1283
1284         free(context);
1285 }
1286
1287 /*
1288  * This is a specialized populate for lttng_event_field since it ignores
1289  * the extension field of the lttng_event struct and simply copies what it can
1290  * to the internal struct lttng_event of a lttng_event_field.
1291  */
1292 static void lttng_event_field_populate_lttng_event_from_event(
1293                 const struct lttng_event *src, struct lttng_event *destination)
1294 {
1295         memcpy(destination, src, sizeof(*destination));
1296
1297         /* Remove all possible dynamic data from the destination event rule. */
1298         destination->extended.ptr = NULL;
1299 }
1300
1301 ssize_t lttng_event_field_create_from_payload(
1302                 struct lttng_payload_view *view,
1303                 struct lttng_event_field **field)
1304 {
1305         ssize_t ret, offset = 0;
1306         struct lttng_event_field *local_event_field = NULL;
1307         struct lttng_event *event = NULL;
1308         const struct lttng_event_field_comm *comm;
1309         const char* name = NULL;
1310
1311         assert(field);
1312         assert(view);
1313
1314         {
1315                 const struct lttng_buffer_view comm_view =
1316                                 lttng_buffer_view_from_view(
1317                                                 &view->buffer, offset,
1318                                                 sizeof(*comm));
1319
1320                 if (!lttng_buffer_view_is_valid(&comm_view)) {
1321                         ret = -1;
1322                         goto end;
1323                 }
1324
1325                 /* lttng_event_field_comm header */
1326                 comm = (const lttng_event_field_comm *) comm_view.data;
1327                 offset += sizeof(*comm);
1328         }
1329
1330         local_event_field = zmalloc<lttng_event_field>();
1331         if (!local_event_field) {
1332                 ret = -1;
1333                 goto end;
1334         }
1335
1336         local_event_field->type = (lttng_event_field_type) comm->type;
1337         local_event_field->nowrite = comm->nowrite;
1338
1339         /* Field name */
1340         {
1341                 const struct lttng_buffer_view name_view =
1342                                 lttng_buffer_view_from_view(
1343                                                 &view->buffer, offset,
1344                                                 comm->name_len);
1345
1346                 if (!lttng_buffer_view_is_valid(&name_view)) {
1347                         ret = -1;
1348                         goto end;
1349                 }
1350
1351                 name = name_view.data;
1352
1353                 if (!lttng_buffer_view_contains_string(&name_view,
1354                                 name_view.data, comm->name_len)) {
1355                         ret = -1;
1356                         goto end;
1357                 }
1358
1359                 if (comm->name_len > LTTNG_SYMBOL_NAME_LEN - 1) {
1360                         /* Name is too long.*/
1361                         ret = -1;
1362                         goto end;
1363                 }
1364
1365                 offset += comm->name_len;
1366         }
1367
1368         /* Event */
1369         {
1370                 struct lttng_payload_view event_view =
1371                                 lttng_payload_view_from_view(
1372                                                 view, offset,
1373                                                 comm->event_len);
1374
1375                 if (!lttng_payload_view_is_valid(&event_view)) {
1376                         ret = -1;
1377                         goto end;
1378                 }
1379
1380                 ret = lttng_event_create_from_payload(&event_view, &event, NULL,
1381                                 NULL, NULL);
1382                 if (ret != comm->event_len) {
1383                         ret = -1;
1384                         goto end;
1385                 }
1386
1387                 offset += ret;
1388         }
1389
1390         assert(name);
1391         assert(event);
1392
1393         if (lttng_strncpy(local_event_field->field_name, name,
1394                         sizeof(local_event_field->field_name))) {
1395                 ret = -1;
1396                 goto end;
1397         }
1398
1399         lttng_event_field_populate_lttng_event_from_event(
1400                         event, &local_event_field->event);
1401
1402         *field = local_event_field;
1403         local_event_field = NULL;
1404         ret = offset;
1405 end:
1406         lttng_event_destroy(event);
1407         free(local_event_field);
1408         return ret;
1409 }
1410
1411 int lttng_event_field_serialize(const struct lttng_event_field *field,
1412                 struct lttng_payload *payload)
1413 {
1414         int ret;
1415         size_t header_offset, size_before_event;
1416         size_t name_len;
1417         struct lttng_event_field_comm event_field_comm = {};
1418         struct lttng_event_field_comm *header;
1419
1420         assert(field);
1421         assert(payload);
1422
1423         /* Save the header location for later in-place header update. */
1424         header_offset = payload->buffer.size;
1425
1426         name_len = strnlen(field->field_name, sizeof(field->field_name));
1427         if (name_len == sizeof(field->field_name)) {
1428                 /* Event name is not NULL-terminated. */
1429                 ret = -1;
1430                 goto end;
1431         }
1432
1433         /* Add null termination. */
1434         name_len += 1;
1435
1436         event_field_comm.type = field->type;
1437         event_field_comm.nowrite = (uint8_t)field->nowrite;
1438         event_field_comm.name_len = name_len;
1439
1440         /* Header */
1441         ret = lttng_dynamic_buffer_append(
1442                         &payload->buffer, &event_field_comm,
1443                         sizeof(event_field_comm));
1444         if (ret) {
1445                 goto end;
1446         }
1447
1448         /* Field name */
1449         ret = lttng_dynamic_buffer_append(&payload->buffer, field->field_name,
1450                         name_len);
1451         if (ret) {
1452                 goto end;
1453         }
1454
1455         size_before_event = payload->buffer.size;
1456         ret = lttng_event_serialize(
1457                         &field->event, 0, NULL, NULL, 0, 0, payload);
1458         if (ret) {
1459                 ret = -1;
1460                 goto end;
1461         }
1462
1463         /* Update the event len. */
1464         header = (struct lttng_event_field_comm *)
1465                         ((char *) payload->buffer.data +
1466                                 header_offset);
1467         header->event_len = payload->buffer.size - size_before_event;
1468
1469 end:
1470         return ret;
1471 }
1472
1473 static enum lttng_error_code compute_flattened_size(
1474                 struct lttng_dynamic_pointer_array *events, size_t *size)
1475 {
1476         enum lttng_error_code ret_code;
1477         int ret = 0;
1478         size_t storage_req, event_count, i;
1479
1480         assert(size);
1481         assert(events);
1482
1483         event_count = lttng_dynamic_pointer_array_get_count(events);
1484
1485         /* The basic struct lttng_event */
1486         storage_req = event_count * sizeof(struct lttng_event);
1487
1488         /* The struct·lttng_event_extended */
1489         storage_req += event_count * sizeof(struct lttng_event_extended);
1490
1491         for (i = 0; i < event_count; i++) {
1492                 int probe_storage_req = 0;
1493                 const struct event_list_element *element = (const struct event_list_element *)
1494                                 lttng_dynamic_pointer_array_get_pointer(
1495                                                 events, i);
1496                 const struct lttng_userspace_probe_location *location = NULL;
1497
1498                 location = lttng_event_get_userspace_probe_location(
1499                                 element->event);
1500                 if (location) {
1501                         ret = lttng_userspace_probe_location_flatten(
1502                                         location, NULL);
1503                         if (ret < 0) {
1504                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1505                                 goto end;
1506                         }
1507
1508                         probe_storage_req = ret;
1509                 }
1510
1511                 if (element->filter_expression) {
1512                         storage_req += strlen(element->filter_expression) + 1;
1513                 }
1514
1515                 if (element->exclusions) {
1516                         storage_req += element->exclusions->count *
1517                                 LTTNG_SYMBOL_NAME_LEN;
1518                 }
1519
1520                 /* Padding to ensure the flat probe is aligned. */
1521                 storage_req = lttng_align_ceil(storage_req, sizeof(uint64_t));
1522                 storage_req += probe_storage_req;
1523         }
1524
1525         *size = storage_req;
1526         ret_code = LTTNG_OK;
1527
1528 end:
1529         return ret_code;
1530 }
1531
1532 /*
1533  * Flatten a list of struct lttng_event.
1534  *
1535  * The buffer that is returned to the API client  must contain a "flat" version
1536  * of the events that are returned. In other words, all pointers within an
1537  * lttng_event must point to a location within the returned buffer so that the
1538  * user may free everything by simply calling free() on the returned buffer.
1539  * This is needed in order to maintain API compatibility.
1540  *
1541  * A first pass is performed to compute the size of the buffer that must be
1542  * allocated. A second pass is then performed to setup the returned events so
1543  * that their members always point within the buffer.
1544  *
1545  * The layout of the returned buffer is as follows:
1546  *   - struct lttng_event[nb_events],
1547  *   - nb_events times the following:
1548  *     - struct lttng_event_extended,
1549  *     - filter_expression
1550  *     - exclusions
1551  *     - padding to align to 64-bits
1552  *     - flattened version of userspace_probe_location
1553  */
1554 static enum lttng_error_code flatten_lttng_events(
1555                 struct lttng_dynamic_pointer_array *events,
1556                 struct lttng_event **flattened_events)
1557 {
1558         enum lttng_error_code ret_code;
1559         int ret, i;
1560         size_t storage_req;
1561         struct lttng_dynamic_buffer local_flattened_events;
1562         int nb_events;
1563
1564         assert(events);
1565         assert(flattened_events);
1566
1567         lttng_dynamic_buffer_init(&local_flattened_events);
1568         nb_events = lttng_dynamic_pointer_array_get_count(events);
1569
1570         ret_code = compute_flattened_size(events, &storage_req);
1571         if (ret_code != LTTNG_OK) {
1572                 goto end;
1573         }
1574
1575         /*
1576          * We must ensure that "local_flattened_events" is never resized so as
1577          * to preserve the validity of the flattened objects.
1578          */
1579         ret = lttng_dynamic_buffer_set_capacity(
1580                         &local_flattened_events, storage_req);
1581         if (ret) {
1582                 ret_code = LTTNG_ERR_NOMEM;
1583                 goto end;
1584         }
1585
1586         /* Start by laying the struct lttng_event */
1587         for (i = 0; i < nb_events; i++) {
1588                 const struct event_list_element *element = (const struct event_list_element *)
1589                                 lttng_dynamic_pointer_array_get_pointer(
1590                                                 events, i);
1591
1592                 if (!element) {
1593                         ret_code = LTTNG_ERR_FATAL;
1594                         goto end;
1595                 }
1596
1597                 ret = lttng_dynamic_buffer_append(&local_flattened_events,
1598                                 element->event, sizeof(struct lttng_event));
1599                 if (ret) {
1600                         ret_code = LTTNG_ERR_NOMEM;
1601                         goto end;
1602                 }
1603         }
1604
1605         for (i = 0; i < nb_events; i++) {
1606                 const struct event_list_element *element = (const struct event_list_element *)
1607                                 lttng_dynamic_pointer_array_get_pointer(events, i);
1608                 struct lttng_event *event = (struct lttng_event *)
1609                         (local_flattened_events.data + (sizeof(struct lttng_event) * i));
1610                 struct lttng_event_extended *event_extended =
1611                         (struct lttng_event_extended *)
1612                                 (local_flattened_events.data + local_flattened_events.size);
1613                 const struct lttng_userspace_probe_location *location = NULL;
1614
1615                 assert(element);
1616
1617                 /* Insert struct lttng_event_extended. */
1618                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1619                                 local_flattened_events.size +
1620                                                 sizeof(*event_extended));
1621                 if (ret) {
1622                         ret_code = LTTNG_ERR_NOMEM;
1623                         goto end;
1624                 }
1625                 event->extended.ptr = event_extended;
1626
1627                 /* Insert filter expression. */
1628                 if (element->filter_expression) {
1629                         const size_t len = strlen(element->filter_expression) + 1;
1630
1631                         event_extended->filter_expression =
1632                                         local_flattened_events.data +
1633                                         local_flattened_events.size;
1634                         ret = lttng_dynamic_buffer_append(
1635                                         &local_flattened_events,
1636                                         element->filter_expression, len);
1637                         if (ret) {
1638                                 ret_code = LTTNG_ERR_NOMEM;
1639                                 goto end;
1640                         }
1641                 }
1642
1643                 /* Insert exclusions. */
1644                 if (element->exclusions) {
1645                         event_extended->exclusions.count =
1646                                         element->exclusions->count;
1647                         event_extended->exclusions.strings =
1648                                         local_flattened_events.data +
1649                                         local_flattened_events.size;
1650
1651                         ret = lttng_dynamic_buffer_append(
1652                                         &local_flattened_events,
1653                                         element->exclusions->names,
1654                                         element->exclusions->count *
1655                                                         LTTNG_SYMBOL_NAME_LEN);
1656                         if (ret) {
1657                                 ret_code = LTTNG_ERR_NOMEM;
1658                                 goto end;
1659                         }
1660                 }
1661
1662                 /* Insert padding to align to 64-bits. */
1663                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1664                                 lttng_align_ceil(local_flattened_events.size,
1665                                                 sizeof(uint64_t)));
1666                 if (ret) {
1667                         ret_code = LTTNG_ERR_NOMEM;
1668                         goto end;
1669                 }
1670
1671                 location = lttng_event_get_userspace_probe_location(
1672                                 element->event);
1673                 if (location) {
1674                         event_extended->probe_location = (struct lttng_userspace_probe_location *)
1675                                         (local_flattened_events.data + local_flattened_events.size);
1676                         ret = lttng_userspace_probe_location_flatten(
1677                                         location, &local_flattened_events);
1678                         if (ret < 0) {
1679                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1680                                 goto end;
1681                         }
1682                 }
1683         }
1684
1685         /* Don't reset local_flattened_events buffer as we return its content. */
1686         *flattened_events = (struct lttng_event *) local_flattened_events.data;
1687         lttng_dynamic_buffer_init(&local_flattened_events);
1688         ret_code = LTTNG_OK;
1689 end:
1690         lttng_dynamic_buffer_reset(&local_flattened_events);
1691         return ret_code;
1692 }
1693
1694 static enum lttng_error_code event_list_create_from_payload(
1695                 struct lttng_payload_view *view,
1696                 unsigned int count,
1697                 struct lttng_dynamic_pointer_array *event_list)
1698 {
1699         enum lttng_error_code ret_code;
1700         int ret;
1701         unsigned int i;
1702         int offset = 0;
1703
1704         assert(view);
1705         assert(event_list);
1706
1707         for (i = 0; i < count; i++) {
1708                 ssize_t event_size;
1709                 struct lttng_payload_view event_view =
1710                                 lttng_payload_view_from_view(view, offset, -1);
1711                 struct event_list_element *element = zmalloc<event_list_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 = zmalloc<lttng_dynamic_pointer_array>();
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 }