src/common/event.c

   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 <lttng/constant.h>
  18 #include <lttng/event-internal.h>
  19 #include <lttng/event.h>
  20 #include <lttng/userspace-probe-internal.h>
  21 #include <stdint.h>
  22 #include <string.h>
  23
  24 struct event_list_element {
  25         struct lttng_event *event;
  26         struct lttng_event_exclusion *exclusions;
  27         char *filter_expression;
  28 };
  29
  30 static void event_list_destructor(void *ptr)
  31 {
  32         struct event_list_element *element = (struct event_list_element *) ptr;
  33
  34         free(element->filter_expression);
  35         free(element->exclusions);
  36         lttng_event_destroy(element->event);
  37         free(element);
  38 }
  39
  40 LTTNG_HIDDEN
  41 struct lttng_event *lttng_event_copy(const struct lttng_event *event)
  42 {
  43         struct lttng_event *new_event;
  44         struct lttng_event_extended *new_event_extended;
  45
  46         new_event = zmalloc(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 = 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_dynamic_buffer *buf)
  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(buf, &comm, sizeof(comm));
  97         if (ret < 0) {
  98                 ret = -1;
  99                 goto end;
 100         }
 101
 102         ret = lttng_dynamic_buffer_append(buf, probe->symbol_name, symbol_name_len);
 103
 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_dynamic_buffer *buf)
 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(function->symbol_name, LTTNG_SYMBOL_NAME_LEN);
 117         if (symbol_name_len == LTTNG_SYMBOL_NAME_LEN) {
 118                 /* Not null-termintated. */
 119                 ret = -1;
 120                 goto end;
 121         }
 122
 123         /* Include the null terminator. */
 124         symbol_name_len += 1;
 125
 126         comm.symbol_name_len = (uint32_t) symbol_name_len;
 127
 128         ret = lttng_dynamic_buffer_append(buf, &comm, sizeof(comm));
 129         if (ret < 0) {
 130                 ret = -1;
 131                 goto end;
 132         }
 133
 134         ret = lttng_dynamic_buffer_append(buf, function->symbol_name, symbol_name_len);
 135 end:
 136         return ret;
 137 }
 138
 139 static ssize_t lttng_event_probe_attr_create_from_buffer(
 140                 const struct lttng_buffer_view *view,
 141                 struct lttng_event_probe_attr **probe_attr)
 142 {
 143         ssize_t ret, offset = 0;
 144         const struct lttng_event_probe_attr_comm *comm;
 145         struct lttng_event_probe_attr *local_attr = NULL;
 146         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
 147                         view, offset, sizeof(*comm));
 148
 149         if (!lttng_buffer_view_is_valid(&comm_view)) {
 150                 ret = -1;
 151                 goto end;
 152         }
 153
 154         comm = (typeof(comm)) view->data;
 155         offset += sizeof(*comm);
 156
 157         local_attr = zmalloc(sizeof(*local_attr));
 158         if (local_attr == NULL) {
 159                 ret = -1;
 160                 goto end;
 161         }
 162
 163         local_attr->addr = comm->addr;
 164         local_attr->offset = comm->offset;
 165
 166         {
 167                 const char *name;
 168                 const struct lttng_buffer_view name_view =
 169                                 lttng_buffer_view_from_view(view, offset,
 170                                                 comm->symbol_name_len);
 171                 if (!lttng_buffer_view_is_valid(&name_view)) {
 172                         ret = -1;
 173                         goto end;
 174                 }
 175
 176                 name = name_view.data;
 177
 178                 if (!lttng_buffer_view_contains_string(
 179                                 &name_view, name, comm->symbol_name_len)) {
 180                         ret = -1;
 181                         goto end;
 182                 }
 183
 184                 ret = lttng_strncpy(local_attr->symbol_name, name,
 185                                 LTTNG_SYMBOL_NAME_LEN);
 186                 if (ret) {
 187                         ret = -1;
 188                         goto end;
 189                 }
 190                 offset += comm->symbol_name_len;
 191         }
 192
 193         *probe_attr = local_attr;
 194         local_attr = NULL;
 195         ret = offset;
 196 end:
 197         return ret;
 198 }
 199
 200 static ssize_t lttng_event_function_attr_create_from_buffer(
 201                 const struct lttng_buffer_view *view,
 202                 struct lttng_event_function_attr **function_attr)
 203 {
 204         ssize_t ret, offset = 0;
 205         const struct lttng_event_function_attr_comm *comm;
 206         struct lttng_event_function_attr *local_attr = NULL;
 207         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
 208                         view, offset, sizeof(*comm));
 209
 210         if (!lttng_buffer_view_is_valid(&comm_view)) {
 211                 ret = -1;
 212                 goto end;
 213         }
 214
 215         comm = (typeof(comm)) view->data;
 216         offset += sizeof(*comm);
 217
 218         local_attr = zmalloc(sizeof(*local_attr));
 219         if (local_attr == NULL) {
 220                 ret = -1;
 221                 goto end;
 222         }
 223
 224         {
 225                 const char *name;
 226                 const struct lttng_buffer_view name_view =
 227                                 lttng_buffer_view_from_view(view, offset,
 228                                                 comm->symbol_name_len);
 229                 if (!lttng_buffer_view_is_valid(&name_view)) {
 230                         ret = -1;
 231                         goto end;
 232                 }
 233
 234                 name = name_view.data;
 235
 236                 if (!lttng_buffer_view_contains_string(
 237                                 &name_view, name, comm->symbol_name_len)) {
 238                         ret = -1;
 239                         goto end;
 240                 }
 241
 242                 ret = lttng_strncpy(local_attr->symbol_name, name,
 243                                 LTTNG_SYMBOL_NAME_LEN);
 244                 if (ret) {
 245                         ret = -1;
 246                         goto end;
 247                 }
 248                 offset += comm->symbol_name_len;
 249         }
 250
 251         *function_attr = local_attr;
 252         local_attr = NULL;
 253         ret = offset;
 254 end:
 255         return ret;
 256 }
 257
 258 static ssize_t lttng_event_exclusions_create_from_buffer(const struct lttng_buffer_view *view,
 259                 uint32_t count,  struct lttng_event_exclusion **exclusions)
 260 {
 261         ssize_t ret, offset = 0;
 262         size_t size = (count * LTTNG_SYMBOL_NAME_LEN);
 263         uint32_t i;
 264         const struct lttng_event_exclusion_comm *comm;
 265         struct lttng_event_exclusion *local_exclusions;
 266
 267
 268         local_exclusions = zmalloc(sizeof(struct lttng_event_exclusion) + size);
 269         if (!local_exclusions) {
 270                 ret = -1;
 271                 goto end;
 272         }
 273         local_exclusions->count = count;
 274
 275         for (i = 0; i < count; i++) {
 276                 const char *string;
 277                 struct lttng_buffer_view string_view;
 278                 const struct lttng_buffer_view comm_view =
 279                                 lttng_buffer_view_from_view(
 280                                                 view, offset, sizeof(*comm));
 281
 282                 if (!lttng_buffer_view_is_valid(&comm_view)) {
 283                         ret = -1;
 284                         goto end;
 285                 }
 286
 287                 comm = (typeof(comm)) comm_view.data;
 288                 offset += sizeof(*comm);
 289
 290                 string_view = lttng_buffer_view_from_view(
 291                                 view, offset, comm->len);
 292
 293                 if (!lttng_buffer_view_is_valid(&string_view)) {
 294                         ret = -1;
 295                         goto end;
 296                 }
 297
 298                 string = string_view.data;
 299
 300                 if (!lttng_buffer_view_contains_string(
 301                                     &string_view, string, comm->len)) {
 302                         ret = -1;
 303                         goto end;
 304                 }
 305
 306                 ret = lttng_strncpy(
 307                                 local_exclusions->names[i],
 308                                 string, comm->len);
 309                 if (ret) {
 310                         ret = -1;
 311                         goto end;
 312                 }
 313                 offset += comm->len;
 314         }
 315
 316         *exclusions = local_exclusions;
 317         local_exclusions = NULL;
 318         ret = offset;
 319 end:
 320         free(local_exclusions);
 321         return ret;
 322 }
 323
 324
 325 LTTNG_HIDDEN
 326 ssize_t lttng_event_create_from_buffer(const struct lttng_buffer_view *view,
 327                 struct lttng_event **event,
 328                 struct lttng_event_exclusion **exclusion,
 329                 char **filter_expression,
 330                 struct lttng_filter_bytecode **bytecode,
 331                 int sock)
 332 {
 333         ssize_t ret, offset = 0;
 334         struct lttng_event *local_event = NULL;
 335         struct lttng_event_exclusion *local_exclusions = NULL;
 336         struct lttng_filter_bytecode *local_bytecode = NULL;
 337         char *local_filter_expression = NULL;
 338         const struct lttng_event_comm *event_comm;
 339         struct lttng_event_function_attr *local_function_attr = NULL;
 340         struct lttng_event_probe_attr *local_probe_attr = NULL;
 341         struct lttng_userspace_probe_location *local_userspace_probe_location =
 342                         NULL;
 343         int received_fd = -1;
 344
 345         /*
 346          * Only event is obligatory, the other output argument are optional and
 347          * depends on what the caller is interested in.
 348          */
 349         assert(event);
 350         assert(view);
 351
 352         {
 353                 const struct lttng_buffer_view comm_view =
 354                                 lttng_buffer_view_from_view(view, offset,
 355                                                 sizeof(*event_comm));
 356
 357                 if (!lttng_buffer_view_is_valid(&comm_view)) {
 358                         ret = -1;
 359                         goto end;
 360                 }
 361
 362                 /* lttng_event_comm header */
 363                 event_comm = (typeof(event_comm)) comm_view.data;
 364                 offset += sizeof(*event_comm);
 365         }
 366
 367         local_event = lttng_event_create();
 368         if (local_event == NULL) {
 369                 ret = -1;
 370                 goto end;
 371         }
 372
 373         local_event->type = event_comm->event_type;
 374         local_event->loglevel_type = event_comm->loglevel_type;
 375         local_event->loglevel = event_comm->loglevel;
 376         local_event->enabled = event_comm->enabled;
 377         local_event->pid = event_comm->pid;
 378         local_event->flags = event_comm->flags;
 379
 380         {
 381                 const char *name;
 382                 const struct lttng_buffer_view name_view =
 383                                 lttng_buffer_view_from_view(view, offset,
 384                                                 event_comm->name_len);
 385                 if (!lttng_buffer_view_is_valid(&name_view)) {
 386                         ret = -1;
 387                         goto end;
 388                 }
 389
 390                 name = name_view.data;
 391
 392                 if (!lttng_buffer_view_contains_string(
 393                                     &name_view, name, event_comm->name_len)) {
 394                         ret = -1;
 395                         goto end;
 396                 }
 397
 398                 ret = lttng_strncpy(
 399                                 local_event->name, name, LTTNG_SYMBOL_NAME_LEN);
 400                 if (ret) {
 401                         ret = -1;
 402                         goto end;
 403                 }
 404                 offset += event_comm->name_len;
 405         }
 406
 407         /* Exclusions */
 408         if (event_comm->exclusion_count == 0) {
 409                 goto deserialize_filter_expression;
 410         }
 411
 412         {
 413
 414                 const struct lttng_buffer_view exclusions_view =
 415                                 lttng_buffer_view_from_view(
 416                                                 view, offset, -1);
 417
 418                 if (!lttng_buffer_view_is_valid(&exclusions_view)) {
 419                         ret = -1;
 420                         goto end;
 421                 }
 422
 423                 ret = lttng_event_exclusions_create_from_buffer(&exclusions_view,
 424                                 event_comm->exclusion_count, &local_exclusions);
 425                 if (ret < 0) {
 426                         ret = -1;
 427                         goto end;
 428                 }
 429                 offset += ret;
 430
 431                 local_event->exclusion = 1;
 432         }
 433
 434 deserialize_filter_expression:
 435
 436         if (event_comm->filter_expression_len == 0) {
 437                 if (event_comm->bytecode_len != 0) {
 438                         /*
 439                          * This is an invalid event payload.
 440                          *
 441                          * Filter expression without bytecode is possible but
 442                          * not the other way around.
 443                          * */
 444                         ret = -1;
 445                         goto end;
 446                 }
 447                 goto deserialize_event_type_payload;
 448         }
 449
 450         {
 451                 const char *filter_expression_buffer;
 452                 const struct lttng_buffer_view filter_expression_view =
 453                                 lttng_buffer_view_from_view(view, offset,
 454                                                 event_comm->filter_expression_len);
 455
 456                 if (!lttng_buffer_view_is_valid(&filter_expression_view)) {
 457                         ret = -1;
 458                         goto end;
 459                 }
 460
 461                 filter_expression_buffer = filter_expression_view.data;
 462
 463                 if (!lttng_buffer_view_contains_string(&filter_expression_view,
 464                                     filter_expression_buffer,
 465                                     event_comm->filter_expression_len)) {
 466                         ret = -1;
 467                         goto end;
 468                 }
 469
 470                 local_filter_expression = lttng_strndup(
 471                                 filter_expression_buffer,
 472                                 event_comm->filter_expression_len);
 473                 if (!local_filter_expression) {
 474                         ret = -1;
 475                         goto end;
 476                 }
 477
 478                 local_event->filter = 1;
 479
 480                 offset += event_comm->filter_expression_len;
 481         }
 482
 483         if (event_comm->bytecode_len == 0) {
 484                 /*
 485                  * Filter expression can be present but without bytecode
 486                  * when dealing with event listing.
 487                  */
 488                 goto deserialize_event_type_payload;
 489         }
 490
 491         /* Bytecode */
 492         {
 493                 const struct lttng_buffer_view bytecode_view =
 494                                 lttng_buffer_view_from_view(view, offset,
 495                                                 event_comm->bytecode_len);
 496
 497                 if (!lttng_buffer_view_is_valid(&bytecode_view)) {
 498                         ret = -1;
 499                         goto end;
 500                 }
 501
 502                 local_bytecode = zmalloc(event_comm->bytecode_len);
 503                 if (!local_bytecode) {
 504                         ret = -1;
 505                         goto end;
 506                 }
 507
 508                 memcpy(local_bytecode, bytecode_view.data,
 509                                 event_comm->bytecode_len);
 510                 if ((local_bytecode->len + sizeof(*local_bytecode)) !=
 511                                 event_comm->bytecode_len) {
 512                         ret = -1;
 513                         goto end;
 514                 }
 515
 516                 offset += event_comm->bytecode_len;
 517         }
 518
 519 deserialize_event_type_payload:
 520         /* Event type specific payload */
 521         switch (local_event->type) {
 522         case LTTNG_EVENT_FUNCTION:
 523                 /* Fallthrough */
 524         case LTTNG_EVENT_PROBE:
 525         {
 526                 const struct lttng_buffer_view probe_attr_view =
 527                                 lttng_buffer_view_from_view(view, offset,
 528                                                 event_comm->lttng_event_probe_attr_len);
 529
 530                 if (event_comm->lttng_event_probe_attr_len == 0) {
 531                         ret = -1;
 532                         goto end;
 533                 }
 534
 535                 if (!lttng_buffer_view_is_valid(&probe_attr_view)) {
 536                         ret = -1;
 537                         goto end;
 538                 }
 539
 540                 ret = lttng_event_probe_attr_create_from_buffer(
 541                                 &probe_attr_view, &local_probe_attr);
 542                 if (ret < 0 || ret != event_comm->lttng_event_probe_attr_len) {
 543                         ret = -1;
 544                         goto end;
 545                 }
 546
 547                 /* Copy to the local event. */
 548                 memcpy(&local_event->attr.probe, local_probe_attr,
 549                                 sizeof(local_event->attr.probe));
 550
 551                 offset += ret;
 552                 break;
 553         }
 554         case LTTNG_EVENT_FUNCTION_ENTRY:
 555         {
 556                 const struct lttng_buffer_view function_attr_view =
 557                                 lttng_buffer_view_from_view(view, offset,
 558                                                 event_comm->lttng_event_function_attr_len);
 559
 560                 if (event_comm->lttng_event_function_attr_len == 0) {
 561                         ret = -1;
 562                         goto end;
 563                 }
 564
 565                 if (!lttng_buffer_view_is_valid(&function_attr_view)) {
 566                         ret = -1;
 567                         goto end;
 568                 }
 569
 570                 ret = lttng_event_function_attr_create_from_buffer(
 571                                 &function_attr_view, &local_function_attr);
 572                 if (ret < 0 || ret != event_comm->lttng_event_function_attr_len) {
 573                         ret = -1;
 574                         goto end;
 575                 }
 576
 577                 /* Copy to the local event. */
 578                 memcpy(&local_event->attr.ftrace, local_function_attr,
 579                                 sizeof(local_event->attr.ftrace));
 580
 581                 offset += ret;
 582
 583                 break;
 584         }
 585         case LTTNG_EVENT_USERSPACE_PROBE:
 586         {
 587                 const struct lttng_buffer_view userspace_probe_location_view =
 588                                 lttng_buffer_view_from_view(view, offset,
 589                                                 event_comm->userspace_probe_location_len);
 590                 const struct lttng_userspace_probe_location_lookup_method
 591                                 *lookup = NULL;
 592
 593                 if (event_comm->userspace_probe_location_len == 0) {
 594                         ret = -1;
 595                         goto end;
 596                 }
 597
 598                 if (!lttng_buffer_view_is_valid(
 599                                     &userspace_probe_location_view)) {
 600                         ret = -1;
 601                         goto end;
 602                 }
 603
 604                 ret = lttng_userspace_probe_location_create_from_buffer(
 605                                 &userspace_probe_location_view,
 606                                 &local_userspace_probe_location);
 607                 if (ret < 0) {
 608                         WARN("Failed to create a userspace probe location from the received buffer");
 609                         ret = -1;
 610                         goto end;
 611                 }
 612
 613                 if (ret != event_comm->userspace_probe_location_len) {
 614                         WARN("Userspace probe location from the received buffer is not the advertised length: header length = %" PRIu32 ", payload length = %lu", event_comm->userspace_probe_location_len, ret);
 615                         ret = -1;
 616                         goto end;
 617                 }
 618
 619                 if (sock < 0) {
 620                         /*
 621                          * The userspace FD is simply not sent and we do not
 622                          * care about it. This happens on listing.
 623                          */
 624                         goto attach_userspace_probe_to_event;
 625                 }
 626
 627                 /*
 628                  * Receive the file descriptor to the target binary from the
 629                  * client.
 630                  */
 631                 DBG("Receiving userspace probe target FD from client ...");
 632                 ret = lttcomm_recv_fds_unix_sock(sock, &received_fd, 1);
 633                 if (ret <= 0) {
 634                         DBG("Nothing recv() from client userspace probe fd... continuing");
 635                         ret = -1;
 636                         goto end;
 637                 }
 638                 /*
 639                  * Set the file descriptor received from the client through the
 640                  * unix socket in the probe location.
 641                  */
 642                 lookup = lttng_userspace_probe_location_get_lookup_method(
 643                                 local_userspace_probe_location);
 644                 if (!lookup) {
 645                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 646                         goto end;
 647                 }
 648
 649                 /*
 650                  * From the kernel tracer's perspective, all userspace probe
 651                  * event types are all the same: a file and an offset.
 652                  */
 653                 switch (lttng_userspace_probe_location_lookup_method_get_type(
 654                                 lookup)) {
 655                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
 656                         ret = lttng_userspace_probe_location_function_set_binary_fd(
 657                                         local_userspace_probe_location,
 658                                         received_fd);
 659                         break;
 660                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
 661                         ret = lttng_userspace_probe_location_tracepoint_set_binary_fd(
 662                                         local_userspace_probe_location,
 663                                         received_fd);
 664                         break;
 665                 default:
 666                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 667                         goto end;
 668                 }
 669
 670                 if (ret) {
 671                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 672                         goto end;
 673                 }
 674
 675                 /* Fd transfered to the object. */
 676                 received_fd = -1;
 677
 678 attach_userspace_probe_to_event:
 679
 680                 /* Attach the probe location to the event. */
 681                 ret = lttng_event_set_userspace_probe_location(
 682                                 local_event, local_userspace_probe_location);
 683                 if (ret) {
 684                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 685                         goto end;
 686                 }
 687
 688                 /*
 689                  * Userspace probe location object ownership transfered to the
 690                  * event object
 691                  */
 692                 local_userspace_probe_location = NULL;
 693                 offset += event_comm->userspace_probe_location_len;
 694                 break;
 695         }
 696         case LTTNG_EVENT_TRACEPOINT:
 697                 /* Fallthrough */
 698         case LTTNG_EVENT_ALL:
 699                 /* Fallthrough */
 700         case LTTNG_EVENT_SYSCALL:
 701                 /* Fallthrough */
 702         case LTTNG_EVENT_NOOP:
 703                 /* Nothing to do here */
 704                 break;
 705         default:
 706                 ret = LTTNG_ERR_UND;
 707                 goto end;
 708                 break;
 709         }
 710
 711         /* Transfer ownership to the caller. */
 712         *event = local_event;
 713         local_event = NULL;
 714
 715         if (bytecode) {
 716                 *bytecode = local_bytecode;
 717                 local_bytecode = NULL;
 718         }
 719
 720         if (exclusion) {
 721                 *exclusion = local_exclusions;
 722                 local_exclusions = NULL;
 723         }
 724
 725         if (filter_expression) {
 726                 *filter_expression = local_filter_expression;
 727                 local_filter_expression = NULL;
 728         }
 729
 730         ret = offset;
 731 end:
 732         lttng_event_destroy(local_event);
 733         lttng_userspace_probe_location_destroy(local_userspace_probe_location);
 734         free(local_filter_expression);
 735         free(local_exclusions);
 736         free(local_bytecode);
 737         free(local_function_attr);
 738         free(local_probe_attr);
 739         if (received_fd > -1) {
 740                 if (close(received_fd)) {
 741                         PERROR("Failed to close received fd");
 742                 };
 743         }
 744         return ret;
 745 }
 746
 747 LTTNG_HIDDEN
 748 int lttng_event_serialize(const struct lttng_event *event,
 749                 unsigned int exclusion_count,
 750                 char **exclusion_list,
 751                 char *filter_expression,
 752                 size_t bytecode_len,
 753                 void *bytecode,
 754                 struct lttng_dynamic_buffer *buf,
 755                 int *fd_to_send)
 756 {
 757         int ret;
 758         unsigned int i;
 759         size_t header_offset, size_before_payload;
 760         size_t name_len;
 761         struct lttng_event_comm event_comm = { 0 };
 762         struct lttng_event_comm *header;
 763
 764         assert(event);
 765         assert(buf);
 766
 767         /* Save the header location for later in-place header update. */
 768         header_offset = buf->size;
 769
 770         name_len = lttng_strnlen(event->name, LTTNG_SYMBOL_NAME_LEN);
 771         if (name_len == LTTNG_SYMBOL_NAME_LEN) {
 772                 /* Event name is not NULL-terminated. */
 773                 ret = -1;
 774                 goto end;
 775         }
 776
 777         /* Add null termination. */
 778         name_len += 1;
 779
 780         if (exclusion_count > UINT32_MAX) {
 781                 /* Possible overflow. */
 782                 ret = -1;
 783                 goto end;
 784         }
 785
 786         if (bytecode_len > UINT32_MAX) {
 787                 /* Possible overflow. */
 788                 ret = -1;
 789                 goto end;
 790         }
 791
 792         event_comm.name_len = (uint32_t) name_len;
 793         event_comm.event_type = (int8_t) event->type;
 794         event_comm.loglevel_type = (int8_t) event->loglevel_type;
 795         event_comm.loglevel = (int32_t) event->loglevel;
 796         event_comm.enabled = (int8_t) event->enabled;
 797         event_comm.pid = (int32_t) event->pid;
 798         event_comm.exclusion_count = (uint32_t) exclusion_count;
 799         event_comm.bytecode_len = (uint32_t) bytecode_len;
 800         event_comm.flags = (int32_t) event->flags;
 801
 802         if (filter_expression) {
 803                 event_comm.filter_expression_len =
 804                                 strlen(filter_expression) + 1;
 805         }
 806
 807         /* Header */
 808         ret = lttng_dynamic_buffer_append(buf, &event_comm, sizeof(event_comm));
 809         if (ret) {
 810                 goto end;
 811         }
 812
 813         /* Event name */
 814         ret = lttng_dynamic_buffer_append(buf, event->name, name_len);
 815         if (ret) {
 816                 goto end;
 817         }
 818
 819         /* Exclusions */
 820         for (i = 0; i < exclusion_count; i++) {
 821                 size_t exclusion_len;
 822                 struct lttng_event_exclusion_comm exclusion_comm = { 0 };
 823
 824                 assert(exclusion_list);
 825
 826                 exclusion_len = lttng_strnlen(
 827                                 *(exclusion_list + i), LTTNG_SYMBOL_NAME_LEN);
 828                 if (exclusion_len == LTTNG_SYMBOL_NAME_LEN) {
 829                         /* Exclusion is not NULL-terminated. */
 830                         ret = -1;
 831                         goto end;
 832                 }
 833
 834                 /* Include null terminator '\0'. */
 835                 exclusion_len += 1;
 836
 837                 exclusion_comm.len = exclusion_len;
 838
 839                 ret = lttng_dynamic_buffer_append(buf, &exclusion_comm, sizeof(exclusion_comm));
 840                 if (ret) {
 841                         goto end;
 842                 }
 843
 844                 ret = lttng_dynamic_buffer_append(buf, *(exclusion_list + i),
 845                                 exclusion_len);
 846                 if (ret) {
 847                         goto end;
 848                 }
 849         }
 850
 851         /* Filter expression and its bytecode */
 852         if (filter_expression) {
 853                 ret = lttng_dynamic_buffer_append(buf, filter_expression,
 854                                 event_comm.filter_expression_len);
 855                 if (ret) {
 856                         goto end;
 857                 }
 858
 859                 /*
 860                  * Bytecode can be absent when we serialize to the client
 861                  * for listing.
 862                  */
 863                 if (bytecode) {
 864                         ret = lttng_dynamic_buffer_append(
 865                                         buf, bytecode, bytecode_len);
 866                         if (ret) {
 867                                 goto end;
 868                         }
 869                 }
 870         }
 871
 872         size_before_payload = buf->size;
 873
 874         /* Event type specific payload */
 875         switch (event->type) {
 876         case LTTNG_EVENT_FUNCTION:
 877                 /* Fallthrough */
 878         case LTTNG_EVENT_PROBE:
 879                 ret = lttng_event_probe_attr_serialize(&event->attr.probe, buf);
 880                 if (ret) {
 881                         ret = -1;
 882                         goto end;
 883                 }
 884
 885                 header = (struct lttng_event_comm *) ((char *) buf->data +
 886                                                       header_offset);
 887                 header->lttng_event_probe_attr_len =
 888                                 buf->size - size_before_payload;
 889
 890                 break;
 891         case LTTNG_EVENT_FUNCTION_ENTRY:
 892                 ret = lttng_event_function_attr_serialize(
 893                                 &event->attr.ftrace, buf);
 894                 if (ret) {
 895                         ret = -1;
 896                         goto end;
 897                 }
 898
 899                 /* Update the lttng_event_function_attr len. */
 900                 header = (struct lttng_event_comm *) ((char *) buf->data +
 901                                                       header_offset);
 902                 header->lttng_event_function_attr_len =
 903                                 buf->size - size_before_payload;
 904
 905                 break;
 906         case LTTNG_EVENT_USERSPACE_PROBE:
 907         {
 908                 struct lttng_event_extended *ev_ext =
 909                                 (struct lttng_event_extended *)
 910                                                 event->extended.ptr;
 911                 assert(event->extended.ptr);
 912                 assert(ev_ext->probe_location);
 913
 914                 size_before_payload = buf->size;
 915                 if (ev_ext->probe_location) {
 916                         /*
 917                          * lttng_userspace_probe_location_serialize returns the
 918                          * number of bytes that were appended to the buffer.
 919                          */
 920                         ret = lttng_userspace_probe_location_serialize(
 921                                         ev_ext->probe_location, buf,
 922                                         fd_to_send);
 923                         if (ret < 0) {
 924                                 goto end;
 925                         }
 926                         ret = 0;
 927
 928                         /* Update the userspace probe location len. */
 929                         header = (struct lttng_event_comm *) ((char *) buf->data +
 930                                                               header_offset);
 931                         header->userspace_probe_location_len =
 932                                         buf->size - size_before_payload;
 933                 }
 934                 break;
 935         }
 936         case LTTNG_EVENT_TRACEPOINT:
 937                 /* Fallthrough */
 938         case LTTNG_EVENT_ALL:
 939                 /* Fallthrough */
 940         default:
 941                 /* Nothing to do here */
 942                 break;
 943         }
 944
 945 end:
 946         return ret;
 947 }
 948
 949 static ssize_t lttng_event_context_app_populate_from_buffer(
 950                 const struct lttng_buffer_view *view,
 951                 struct lttng_event_context *event_ctx)
 952 {
 953         ssize_t ret, offset = 0;
 954         const struct lttng_event_context_app_comm *comm;
 955         char *provider_name = NULL, *context_name = NULL;
 956         size_t provider_name_len, context_name_len;
 957         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
 958                         view, offset, sizeof(*comm));
 959
 960         assert(event_ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
 961
 962         if (!lttng_buffer_view_is_valid(&comm_view)) {
 963                 ret = -1;
 964                 goto end;
 965         }
 966
 967         comm = (typeof(comm)) comm_view.data;
 968         offset += sizeof(*comm);
 969
 970         provider_name_len = comm->provider_name_len;
 971         context_name_len = comm->ctx_name_len;
 972
 973         if (provider_name_len == 0 || context_name_len == 0) {
 974                 /*
 975                  * Application provider and context names MUST
 976                  * be provided.
 977                  */
 978                 ret = -1;
 979                 goto end;
 980         }
 981
 982         {
 983                 const char *name;
 984                 const struct lttng_buffer_view provider_name_view =
 985                                 lttng_buffer_view_from_view(view, offset,
 986                                                 provider_name_len);
 987
 988                 if (!lttng_buffer_view_is_valid(&provider_name_view)) {
 989                         ret = -1;
 990                         goto end;
 991                 }
 992
 993                 name = provider_name_view.data;
 994
 995                 if (!lttng_buffer_view_contains_string(&provider_name_view,
 996                                     name, provider_name_len)) {
 997                         ret = -1;
 998                         goto end;
 999                 }
1000
1001                 provider_name = lttng_strndup(name, provider_name_len);
1002                 if (!provider_name) {
1003                         ret = -1;
1004                         goto end;
1005                 }
1006                 offset += provider_name_len;
1007         }
1008
1009         {
1010                 const char *name;
1011                 const struct lttng_buffer_view context_name_view =
1012                                 lttng_buffer_view_from_view(
1013                                                 view, offset, context_name_len);
1014
1015                 if (!lttng_buffer_view_is_valid(&context_name_view)) {
1016                         ret = -1;
1017                         goto end;
1018                 }
1019
1020                 name = context_name_view.data;
1021
1022                 if (!lttng_buffer_view_contains_string(&context_name_view, name,
1023                                     context_name_len)) {
1024                         ret = -1;
1025                         goto end;
1026                 }
1027
1028                 context_name = lttng_strndup(name, context_name_len);
1029                 if (!context_name) {
1030                         ret = -1;
1031                         goto end;
1032                 }
1033
1034                 offset += context_name_len;
1035         }
1036
1037         /* Transfer ownership of the strings */
1038         event_ctx->u.app_ctx.provider_name = provider_name;
1039         event_ctx->u.app_ctx.ctx_name = context_name;
1040         provider_name = NULL;
1041         context_name = NULL;
1042
1043         ret = offset;
1044 end:
1045         free(provider_name);
1046         free(context_name);
1047
1048         return ret;
1049 }
1050
1051 static ssize_t lttng_event_context_perf_counter_populate_from_buffer(
1052                 const struct lttng_buffer_view *view,
1053                 struct lttng_event_context *event_ctx)
1054 {
1055         ssize_t ret, offset = 0;
1056         const struct lttng_event_context_perf_counter_comm *comm;
1057         size_t name_len;
1058         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
1059                         view, offset, sizeof(*comm));
1060
1061         assert(event_ctx->ctx == LTTNG_EVENT_CONTEXT_PERF_COUNTER ||
1062                         event_ctx->ctx ==
1063                                         LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER ||
1064                         event_ctx->ctx == LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER);
1065
1066         if (!lttng_buffer_view_is_valid(&comm_view)) {
1067                 ret = -1;
1068                 goto end;
1069         }
1070
1071         comm = (typeof(comm)) comm_view.data;
1072         offset += sizeof(*comm);
1073
1074         name_len = comm->name_len;
1075         {
1076                 const char *name;
1077                 const struct lttng_buffer_view provider_name_view =
1078                                 lttng_buffer_view_from_view(
1079                                                 view, offset, name_len);
1080                 if (!lttng_buffer_view_is_valid(&provider_name_view)) {
1081                         ret = -1;
1082                         goto end;
1083                 }
1084
1085                 name = provider_name_view.data;
1086
1087                 if (!lttng_buffer_view_contains_string(
1088                                     &provider_name_view, name, name_len)) {
1089                         ret = -1;
1090                         goto end;
1091                 }
1092
1093                 lttng_strncpy(event_ctx->u.perf_counter.name, name, name_len);
1094                 offset += name_len;
1095         }
1096
1097         event_ctx->u.perf_counter.config = comm->config;
1098         event_ctx->u.perf_counter.type = comm->type;
1099
1100         ret = offset;
1101
1102 end:
1103         return ret;
1104 }
1105
1106 LTTNG_HIDDEN
1107 ssize_t lttng_event_context_create_from_buffer(
1108                 const struct lttng_buffer_view *view,
1109                 struct lttng_event_context **event_ctx)
1110 {
1111         ssize_t ret, offset = 0;
1112         const struct lttng_event_context_comm *comm;
1113         struct lttng_event_context *local_context = NULL;
1114         struct lttng_buffer_view subtype_view;
1115         struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
1116                         view, offset, sizeof(*comm));
1117
1118         assert(event_ctx);
1119         assert(view);
1120
1121         if (!lttng_buffer_view_is_valid(&comm_view)) {
1122                 ret = -1;
1123                 goto end;
1124         }
1125
1126         comm = (typeof(comm)) comm_view.data;
1127         offset += sizeof(*comm);
1128
1129         local_context = zmalloc(sizeof(*local_context));
1130         if (!local_context) {
1131                 ret = -1;
1132                 goto end;
1133         }
1134
1135         local_context->ctx = comm->type;
1136
1137         subtype_view = lttng_buffer_view_from_view(view, offset, -1);
1138
1139         switch (local_context->ctx) {
1140         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1141                 ret = lttng_event_context_app_populate_from_buffer(
1142                                 &subtype_view, local_context);
1143                 break;
1144         case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1145         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1146         case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1147                 ret = lttng_event_context_perf_counter_populate_from_buffer(
1148                                 &subtype_view, local_context);
1149                 break;
1150         default:
1151                 /* Nothing else to deserialize. */
1152                 ret = 0;
1153                 break;
1154         }
1155
1156         if (ret < 0) {
1157                 goto end;
1158         }
1159
1160         offset += ret;
1161
1162         *event_ctx = local_context;
1163         local_context = NULL;
1164         ret = offset;
1165
1166 end:
1167         free(local_context);
1168         return ret;
1169 }
1170
1171 static int lttng_event_context_app_serialize(
1172                 struct lttng_event_context *context,
1173                 struct lttng_dynamic_buffer *buffer)
1174 {
1175         int ret;
1176         struct lttng_event_context_app_comm comm = { 0 };
1177         size_t provider_len, ctx_len;
1178         const char *provider_name;
1179         const char *ctx_name;
1180
1181         assert(buffer);
1182         assert(context);
1183         assert(context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
1184
1185         provider_name = context->u.app_ctx.provider_name;
1186         ctx_name = context->u.app_ctx.ctx_name;
1187
1188         if (!provider_name || !ctx_name) {
1189                 ret = -LTTNG_ERR_INVALID;
1190                 goto end;
1191         }
1192
1193         provider_len = strlen(provider_name);
1194         if (provider_len == 0) {
1195                 ret = -LTTNG_ERR_INVALID;
1196                 goto end;
1197         }
1198
1199         /* Include the null terminator. */
1200         comm.provider_name_len = provider_len + 1;
1201
1202         ctx_len = strlen(ctx_name);
1203         if (ctx_len == 0) {
1204                 ret = -LTTNG_ERR_INVALID;
1205                 goto end;
1206         }
1207
1208         /* Include the null terminator. */
1209         comm.ctx_name_len = ctx_len + 1;
1210
1211         /* Header */
1212         ret = lttng_dynamic_buffer_append(buffer, &comm, sizeof(comm));
1213         if (ret) {
1214                 ret = -1;
1215                 goto end;
1216         }
1217
1218         ret = lttng_dynamic_buffer_append(buffer, provider_name, provider_len);
1219         if (ret) {
1220                 ret = -1;
1221                 goto end;
1222         }
1223         ret = lttng_dynamic_buffer_append(buffer, ctx_name, ctx_len);
1224         if (ret) {
1225                 ret = -1;
1226                 goto end;
1227         }
1228
1229 end:
1230         return ret;
1231 }
1232
1233 static int lttng_event_context_perf_counter_serialize(
1234                 struct lttng_event_perf_counter_ctx *context,
1235                 struct lttng_dynamic_buffer *buffer)
1236 {
1237         int ret;
1238         struct lttng_event_context_perf_counter_comm comm = { 0 };
1239
1240         assert(buffer);
1241         assert(context);
1242
1243         comm.config = context->config;
1244         comm.type = context->type;
1245         comm.name_len = lttng_strnlen(context->name, LTTNG_SYMBOL_NAME_LEN);
1246
1247         if (comm.name_len == LTTNG_SYMBOL_NAME_LEN) {
1248                 ret = -1;
1249                 goto end;
1250         }
1251
1252         /* Include the null terminator. */
1253         comm.name_len += 1;
1254
1255         /* Header */
1256         ret = lttng_dynamic_buffer_append(buffer, &comm, sizeof(comm));
1257         if (ret) {
1258                 ret = -1;
1259                 goto end;
1260         }
1261
1262         ret = lttng_dynamic_buffer_append(buffer, context->name, comm.name_len);
1263         if (ret) {
1264                 ret = -1;
1265                 goto end;
1266         }
1267
1268 end:
1269         return ret;
1270 }
1271
1272 LTTNG_HIDDEN
1273 int lttng_event_context_serialize(struct lttng_event_context *context,
1274                 struct lttng_dynamic_buffer *buf)
1275 {
1276         int ret;
1277         struct lttng_event_context_comm context_comm = { 0 };
1278
1279         assert(context);
1280         assert(buf);
1281
1282         context_comm.type = (uint32_t) context->ctx;
1283
1284         /* Header */
1285         ret = lttng_dynamic_buffer_append(
1286                         buf, &context_comm, sizeof(context_comm));
1287         if (ret) {
1288                 goto end;
1289         }
1290
1291         switch (context->ctx) {
1292         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1293                 ret = lttng_event_context_app_serialize(context, buf);
1294                 break;
1295         case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1296         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1297         case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1298                 ret = lttng_event_context_perf_counter_serialize(
1299                                 &context->u.perf_counter, buf);
1300                 break;
1301         default:
1302                 /* Nothing else to serialize. */
1303                 break;
1304         }
1305
1306         if (ret) {
1307                 goto end;
1308         }
1309
1310 end:
1311         return ret;
1312 }
1313
1314 LTTNG_HIDDEN
1315 void lttng_event_context_destroy(struct lttng_event_context *context)
1316 {
1317         if (!context) {
1318                 return;
1319         }
1320
1321         if (context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
1322                 free(context->u.app_ctx.provider_name);
1323                 free(context->u.app_ctx.ctx_name);
1324         }
1325
1326         free(context);
1327 }
1328 static enum lttng_error_code compute_flattened_size(
1329                 struct lttng_dynamic_pointer_array *events, size_t *size)
1330 {
1331         enum lttng_error_code ret_code;
1332         int ret = 0;
1333         size_t storage_req, event_count, i;
1334
1335         assert(size);
1336         assert(events);
1337
1338         event_count = lttng_dynamic_pointer_array_get_count(events);
1339
1340         /* The basic struct lttng_event */
1341         storage_req = event_count * sizeof(struct lttng_event);
1342
1343         for (i = 0; i < event_count; i++) {
1344                 int probe_storage_req = 0;
1345                 const struct event_list_element *element =
1346                                 lttng_dynamic_pointer_array_get_pointer(
1347                                                 events, i);
1348                 const struct lttng_userspace_probe_location *location = NULL;
1349
1350                 location = lttng_event_get_userspace_probe_location(
1351                                 element->event);
1352                 if (location) {
1353                         ret = lttng_userspace_probe_location_flatten(
1354                                         location, NULL);
1355                         if (ret < 0) {
1356                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1357                                 goto end;
1358                         }
1359
1360                         probe_storage_req = ret;
1361                 }
1362
1363                 /* The struct·lttng_event_extended */
1364                 storage_req += event_count *
1365                         sizeof(struct lttng_event_extended);
1366
1367                 if (element->filter_expression) {
1368                         storage_req += strlen(element->filter_expression) + 1;
1369                 }
1370
1371                 if (element->exclusions) {
1372                         storage_req += element->exclusions->count *
1373                                 LTTNG_SYMBOL_NAME_LEN;
1374                 }
1375
1376                 /* Padding to ensure the flat probe is aligned. */
1377                 storage_req = ALIGN_TO(storage_req, sizeof(uint64_t));
1378                 storage_req += probe_storage_req;
1379         }
1380
1381         *size = storage_req;
1382         ret_code = LTTNG_OK;
1383
1384 end:
1385         return ret_code;
1386 }
1387
1388 /*
1389  * Flatten a list of struct lttng_event.
1390  *
1391  * The buffer that is returned to the API client  must contain a "flat" version
1392  * of the events that are returned. In other words, all pointers within an
1393  * lttng_event must point to a location within the returned buffer so that the
1394  * user may free everything by simply calling free() on the returned buffer.
1395  * This is needed in order to maintain API compatibility.
1396  *
1397  * A first pass is performed to compute the size of the buffer that must be
1398  * allocated. A second pass is then performed to setup the returned events so
1399  * that their members always point within the buffer.
1400  *
1401  * The layout of the returned buffer is as follows:
1402  *   - struct lttng_event[nb_events],
1403  *   - nb_events times the following:
1404  *     - struct lttng_event_extended,
1405  *     - filter_expression
1406  *     - exclusions
1407  *     - padding to align to 64-bits
1408  *     - flattened version of userspace_probe_location
1409  */
1410 static enum lttng_error_code flatten_lttng_events(
1411                 struct lttng_dynamic_pointer_array *events,
1412                 struct lttng_event **flattened_events)
1413 {
1414         enum lttng_error_code ret_code;
1415         int ret, i;
1416         size_t storage_req;
1417         struct lttng_dynamic_buffer local_flattened_events;
1418         int nb_events;
1419
1420         assert(events);
1421         assert(flattened_events);
1422
1423         lttng_dynamic_buffer_init(&local_flattened_events);
1424         nb_events = lttng_dynamic_pointer_array_get_count(events);
1425
1426         ret_code = compute_flattened_size(events, &storage_req);
1427         if (ret_code != LTTNG_OK) {
1428                 goto end;
1429         }
1430
1431         /*
1432          * We must ensure that "local_flattened_events" is never resized so as
1433          * to preserve the validity of the flattened objects.
1434          */
1435         ret = lttng_dynamic_buffer_set_capacity(
1436                         &local_flattened_events, storage_req);
1437         if (ret) {
1438                 ret_code = LTTNG_ERR_NOMEM;
1439                 goto end;
1440         }
1441
1442         /* Start by laying the struct lttng_event */
1443         for (i = 0; i < nb_events; i++) {
1444                 struct event_list_element *element =
1445                                 lttng_dynamic_pointer_array_get_pointer(
1446                                                 events, i);
1447
1448                 if (!element) {
1449                         ret_code = LTTNG_ERR_FATAL;
1450                         goto end;
1451                 }
1452                 ret = lttng_dynamic_buffer_append(&local_flattened_events,
1453                                 element->event, sizeof(struct lttng_event));
1454                 if (ret) {
1455                         ret_code = LTTNG_ERR_NOMEM;
1456                         goto end;
1457                 }
1458         }
1459
1460         for (i = 0; i < nb_events; i++) {
1461                 struct event_list_element *element = lttng_dynamic_pointer_array_get_pointer(events, i);
1462                 struct lttng_event *event = (struct lttng_event *)
1463                         (local_flattened_events.data + (sizeof(struct lttng_event) * i));
1464                 struct lttng_event_extended *event_extended =
1465                         (struct lttng_event_extended *)
1466                                 (local_flattened_events.data + local_flattened_events.size);
1467                 const struct lttng_userspace_probe_location *location = NULL;
1468
1469                 assert(element);
1470
1471                 /* Insert struct lttng_event_extended. */
1472                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1473                                 local_flattened_events.size +
1474                                                 sizeof(*event_extended));
1475                 if (ret) {
1476                         ret_code = LTTNG_ERR_NOMEM;
1477                         goto end;
1478                 }
1479                 event->extended.ptr = event_extended;
1480
1481                 /* Insert filter expression. */
1482                 if (element->filter_expression) {
1483                         size_t len = strlen(element->filter_expression) + 1;
1484
1485                         event_extended->filter_expression =
1486                                         local_flattened_events.data +
1487                                         local_flattened_events.size;
1488                         ret = lttng_dynamic_buffer_append(
1489                                         &local_flattened_events,
1490                                         element->filter_expression, len);
1491                         if (ret) {
1492                                 ret_code = LTTNG_ERR_NOMEM;
1493                                 goto end;
1494                         }
1495                 }
1496
1497                 /* Insert exclusions. */
1498                 if (element->exclusions) {
1499                         event_extended->exclusions.count =
1500                                         element->exclusions->count;
1501                         event_extended->exclusions.strings =
1502                                         local_flattened_events.data +
1503                                         local_flattened_events.size;
1504
1505                         ret = lttng_dynamic_buffer_append(
1506                                         &local_flattened_events,
1507                                         element->exclusions->names,
1508                                         element->exclusions->count *
1509                                                         LTTNG_SYMBOL_NAME_LEN);
1510                         if (ret) {
1511                                 ret_code = LTTNG_ERR_NOMEM;
1512                                 goto end;
1513                         }
1514                 }
1515
1516                 /* Insert padding to align to 64-bits. */
1517                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1518                                 ALIGN_TO(local_flattened_events.size,
1519                                                 sizeof(uint64_t)));
1520                 if (ret) {
1521                         ret_code = LTTNG_ERR_NOMEM;
1522                         goto end;
1523                 }
1524
1525                 location = lttng_event_get_userspace_probe_location(
1526                                 element->event);
1527                 if (location) {
1528                         event_extended->probe_location = (struct lttng_userspace_probe_location *)
1529                                         (local_flattened_events.data + local_flattened_events.size);
1530                         ret = lttng_userspace_probe_location_flatten(
1531                                         location, &local_flattened_events);
1532                         if (ret < 0) {
1533                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1534                                 goto end;
1535                         }
1536                 }
1537         }
1538
1539         /* Don't reset local_flattened_events buffer as we return its content. */
1540         *flattened_events = (struct lttng_event *) local_flattened_events.data;
1541         lttng_dynamic_buffer_init(&local_flattened_events);
1542         ret_code = LTTNG_OK;
1543 end:
1544         lttng_dynamic_buffer_reset(&local_flattened_events);
1545         return ret_code;
1546 }
1547
1548 static enum lttng_error_code event_list_create_from_buffer(
1549                 const struct lttng_buffer_view *view,
1550                 unsigned int count,
1551                 struct lttng_dynamic_pointer_array *event_list)
1552 {
1553         enum lttng_error_code ret_code;
1554         int ret;
1555         unsigned int i;
1556         int offset = 0;
1557
1558         assert(view);
1559         assert(event_list);
1560
1561         for (i = 0; i < count; i++) {
1562                 ssize_t event_size;
1563                 const struct lttng_buffer_view event_view =
1564                                 lttng_buffer_view_from_view(view, offset, -1);
1565                 struct event_list_element *element = zmalloc(sizeof(*element));
1566
1567                 if (!element) {
1568                         ret_code = LTTNG_ERR_NOMEM;
1569                         goto end;
1570                 }
1571
1572                 /*
1573                  * Lifetime and management of the object is now bound to the
1574                  * array.
1575                  */
1576                 ret = lttng_dynamic_pointer_array_add_pointer(
1577                                 event_list, element);
1578                 if (ret) {
1579                         event_list_destructor(element);
1580                         ret_code = LTTNG_ERR_NOMEM;
1581                         goto end;
1582                 }
1583
1584                 /*
1585                  * Bytecode is not transmitted on listing in any case we do not
1586                  * care about it.
1587                  */
1588                 event_size = lttng_event_create_from_buffer(&event_view,
1589                                 &element->event,
1590                                 &element->exclusions,
1591                                 &element->filter_expression, NULL, -1);
1592                 if (event_size < 0) {
1593                         ret_code = LTTNG_ERR_INVALID;
1594                         goto end;
1595                 }
1596
1597                 offset += event_size;
1598         }
1599
1600         if (view->size != offset) {
1601                 ret_code = LTTNG_ERR_INVALID;
1602                 goto end;
1603         }
1604
1605         ret_code = LTTNG_OK;
1606
1607 end:
1608         return ret_code;
1609 }
1610
1611 LTTNG_HIDDEN
1612 enum lttng_error_code lttng_events_create_and_flatten_from_buffer(
1613                 const struct lttng_buffer_view *view,
1614                 unsigned int count,
1615                 struct lttng_event **events)
1616 {
1617         enum lttng_error_code ret = LTTNG_OK;
1618         struct lttng_dynamic_pointer_array local_events;
1619
1620         lttng_dynamic_pointer_array_init(&local_events, event_list_destructor);
1621
1622         /* Deserialize the events */
1623         {
1624                 const struct lttng_buffer_view events_view =
1625                                 lttng_buffer_view_from_view(view, 0, -1);
1626
1627                 ret = event_list_create_from_buffer(
1628                                 &events_view, count, &local_events);
1629                 if (ret != LTTNG_OK) {
1630                         goto end;
1631                 }
1632         }
1633
1634         ret = flatten_lttng_events(&local_events, events);
1635         if (ret != LTTNG_OK) {
1636                 goto end;
1637         }
1638
1639 end:
1640         lttng_dynamic_pointer_array_reset(&local_events);
1641         return ret;
1642 }