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         free(local_attr);
 198         return ret;
 199 }
 200
 201 static ssize_t lttng_event_function_attr_create_from_buffer(
 202                 const struct lttng_buffer_view *view,
 203                 struct lttng_event_function_attr **function_attr)
 204 {
 205         ssize_t ret, offset = 0;
 206         const struct lttng_event_function_attr_comm *comm;
 207         struct lttng_event_function_attr *local_attr = NULL;
 208         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
 209                         view, offset, sizeof(*comm));
 210
 211         if (!lttng_buffer_view_is_valid(&comm_view)) {
 212                 ret = -1;
 213                 goto end;
 214         }
 215
 216         comm = (typeof(comm)) view->data;
 217         offset += sizeof(*comm);
 218
 219         local_attr = zmalloc(sizeof(*local_attr));
 220         if (local_attr == NULL) {
 221                 ret = -1;
 222                 goto end;
 223         }
 224
 225         {
 226                 const char *name;
 227                 const struct lttng_buffer_view name_view =
 228                                 lttng_buffer_view_from_view(view, offset,
 229                                                 comm->symbol_name_len);
 230                 if (!lttng_buffer_view_is_valid(&name_view)) {
 231                         ret = -1;
 232                         goto end;
 233                 }
 234
 235                 name = name_view.data;
 236
 237                 if (!lttng_buffer_view_contains_string(
 238                                 &name_view, name, comm->symbol_name_len)) {
 239                         ret = -1;
 240                         goto end;
 241                 }
 242
 243                 ret = lttng_strncpy(local_attr->symbol_name, name,
 244                                 LTTNG_SYMBOL_NAME_LEN);
 245                 if (ret) {
 246                         ret = -1;
 247                         goto end;
 248                 }
 249                 offset += comm->symbol_name_len;
 250         }
 251
 252         *function_attr = local_attr;
 253         local_attr = NULL;
 254         ret = offset;
 255 end:
 256         free(local_attr);
 257         return ret;
 258 }
 259
 260 static ssize_t lttng_event_exclusions_create_from_buffer(const struct lttng_buffer_view *view,
 261                 uint32_t count,  struct lttng_event_exclusion **exclusions)
 262 {
 263         ssize_t ret, offset = 0;
 264         size_t size = (count * LTTNG_SYMBOL_NAME_LEN);
 265         uint32_t i;
 266         const struct lttng_event_exclusion_comm *comm;
 267         struct lttng_event_exclusion *local_exclusions;
 268
 269
 270         local_exclusions = zmalloc(sizeof(struct lttng_event_exclusion) + size);
 271         if (!local_exclusions) {
 272                 ret = -1;
 273                 goto end;
 274         }
 275         local_exclusions->count = count;
 276
 277         for (i = 0; i < count; i++) {
 278                 const char *string;
 279                 struct lttng_buffer_view string_view;
 280                 const struct lttng_buffer_view comm_view =
 281                                 lttng_buffer_view_from_view(
 282                                                 view, offset, sizeof(*comm));
 283
 284                 if (!lttng_buffer_view_is_valid(&comm_view)) {
 285                         ret = -1;
 286                         goto end;
 287                 }
 288
 289                 comm = (typeof(comm)) comm_view.data;
 290                 offset += sizeof(*comm);
 291
 292                 string_view = lttng_buffer_view_from_view(
 293                                 view, offset, comm->len);
 294
 295                 if (!lttng_buffer_view_is_valid(&string_view)) {
 296                         ret = -1;
 297                         goto end;
 298                 }
 299
 300                 string = string_view.data;
 301
 302                 if (!lttng_buffer_view_contains_string(
 303                                     &string_view, string, comm->len)) {
 304                         ret = -1;
 305                         goto end;
 306                 }
 307
 308                 ret = lttng_strncpy(
 309                                 local_exclusions->names[i],
 310                                 string, comm->len);
 311                 if (ret) {
 312                         ret = -1;
 313                         goto end;
 314                 }
 315                 offset += comm->len;
 316         }
 317
 318         *exclusions = local_exclusions;
 319         local_exclusions = NULL;
 320         ret = offset;
 321 end:
 322         free(local_exclusions);
 323         return ret;
 324 }
 325
 326
 327 LTTNG_HIDDEN
 328 ssize_t lttng_event_create_from_buffer(const struct lttng_buffer_view *view,
 329                 struct lttng_event **event,
 330                 struct lttng_event_exclusion **exclusion,
 331                 char **filter_expression,
 332                 struct lttng_filter_bytecode **bytecode,
 333                 int sock)
 334 {
 335         ssize_t ret, offset = 0;
 336         struct lttng_event *local_event = NULL;
 337         struct lttng_event_exclusion *local_exclusions = NULL;
 338         struct lttng_filter_bytecode *local_bytecode = NULL;
 339         char *local_filter_expression = NULL;
 340         const struct lttng_event_comm *event_comm;
 341         struct lttng_event_function_attr *local_function_attr = NULL;
 342         struct lttng_event_probe_attr *local_probe_attr = NULL;
 343         struct lttng_userspace_probe_location *local_userspace_probe_location =
 344                         NULL;
 345         int received_fd = -1;
 346
 347         /*
 348          * Only event is obligatory, the other output argument are optional and
 349          * depends on what the caller is interested in.
 350          */
 351         assert(event);
 352         assert(view);
 353
 354         {
 355                 const struct lttng_buffer_view comm_view =
 356                                 lttng_buffer_view_from_view(view, offset,
 357                                                 sizeof(*event_comm));
 358
 359                 if (!lttng_buffer_view_is_valid(&comm_view)) {
 360                         ret = -1;
 361                         goto end;
 362                 }
 363
 364                 /* lttng_event_comm header */
 365                 event_comm = (typeof(event_comm)) comm_view.data;
 366                 offset += sizeof(*event_comm);
 367         }
 368
 369         local_event = lttng_event_create();
 370         if (local_event == NULL) {
 371                 ret = -1;
 372                 goto end;
 373         }
 374
 375         local_event->type = event_comm->event_type;
 376         local_event->loglevel_type = event_comm->loglevel_type;
 377         local_event->loglevel = event_comm->loglevel;
 378         local_event->enabled = event_comm->enabled;
 379         local_event->pid = event_comm->pid;
 380         local_event->flags = event_comm->flags;
 381
 382         {
 383                 const char *name;
 384                 const struct lttng_buffer_view name_view =
 385                                 lttng_buffer_view_from_view(view, offset,
 386                                                 event_comm->name_len);
 387                 if (!lttng_buffer_view_is_valid(&name_view)) {
 388                         ret = -1;
 389                         goto end;
 390                 }
 391
 392                 name = name_view.data;
 393
 394                 if (!lttng_buffer_view_contains_string(
 395                                     &name_view, name, event_comm->name_len)) {
 396                         ret = -1;
 397                         goto end;
 398                 }
 399
 400                 ret = lttng_strncpy(
 401                                 local_event->name, name, LTTNG_SYMBOL_NAME_LEN);
 402                 if (ret) {
 403                         ret = -1;
 404                         goto end;
 405                 }
 406                 offset += event_comm->name_len;
 407         }
 408
 409         /* Exclusions */
 410         if (event_comm->exclusion_count == 0) {
 411                 goto deserialize_filter_expression;
 412         }
 413
 414         {
 415
 416                 const struct lttng_buffer_view exclusions_view =
 417                                 lttng_buffer_view_from_view(
 418                                                 view, offset, -1);
 419
 420                 if (!lttng_buffer_view_is_valid(&exclusions_view)) {
 421                         ret = -1;
 422                         goto end;
 423                 }
 424
 425                 ret = lttng_event_exclusions_create_from_buffer(&exclusions_view,
 426                                 event_comm->exclusion_count, &local_exclusions);
 427                 if (ret < 0) {
 428                         ret = -1;
 429                         goto end;
 430                 }
 431                 offset += ret;
 432
 433                 local_event->exclusion = 1;
 434         }
 435
 436 deserialize_filter_expression:
 437
 438         if (event_comm->filter_expression_len == 0) {
 439                 if (event_comm->bytecode_len != 0) {
 440                         /*
 441                          * This is an invalid event payload.
 442                          *
 443                          * Filter expression without bytecode is possible but
 444                          * not the other way around.
 445                          * */
 446                         ret = -1;
 447                         goto end;
 448                 }
 449                 goto deserialize_event_type_payload;
 450         }
 451
 452         {
 453                 const char *filter_expression_buffer;
 454                 const struct lttng_buffer_view filter_expression_view =
 455                                 lttng_buffer_view_from_view(view, offset,
 456                                                 event_comm->filter_expression_len);
 457
 458                 if (!lttng_buffer_view_is_valid(&filter_expression_view)) {
 459                         ret = -1;
 460                         goto end;
 461                 }
 462
 463                 filter_expression_buffer = filter_expression_view.data;
 464
 465                 if (!lttng_buffer_view_contains_string(&filter_expression_view,
 466                                     filter_expression_buffer,
 467                                     event_comm->filter_expression_len)) {
 468                         ret = -1;
 469                         goto end;
 470                 }
 471
 472                 local_filter_expression = lttng_strndup(
 473                                 filter_expression_buffer,
 474                                 event_comm->filter_expression_len);
 475                 if (!local_filter_expression) {
 476                         ret = -1;
 477                         goto end;
 478                 }
 479
 480                 local_event->filter = 1;
 481
 482                 offset += event_comm->filter_expression_len;
 483         }
 484
 485         if (event_comm->bytecode_len == 0) {
 486                 /*
 487                  * Filter expression can be present but without bytecode
 488                  * when dealing with event listing.
 489                  */
 490                 goto deserialize_event_type_payload;
 491         }
 492
 493         /* Bytecode */
 494         {
 495                 const struct lttng_buffer_view bytecode_view =
 496                                 lttng_buffer_view_from_view(view, offset,
 497                                                 event_comm->bytecode_len);
 498
 499                 if (!lttng_buffer_view_is_valid(&bytecode_view)) {
 500                         ret = -1;
 501                         goto end;
 502                 }
 503
 504                 local_bytecode = zmalloc(event_comm->bytecode_len);
 505                 if (!local_bytecode) {
 506                         ret = -1;
 507                         goto end;
 508                 }
 509
 510                 memcpy(local_bytecode, bytecode_view.data,
 511                                 event_comm->bytecode_len);
 512                 if ((local_bytecode->len + sizeof(*local_bytecode)) !=
 513                                 event_comm->bytecode_len) {
 514                         ret = -1;
 515                         goto end;
 516                 }
 517
 518                 offset += event_comm->bytecode_len;
 519         }
 520
 521 deserialize_event_type_payload:
 522         /* Event type specific payload */
 523         switch (local_event->type) {
 524         case LTTNG_EVENT_FUNCTION:
 525                 /* Fallthrough */
 526         case LTTNG_EVENT_PROBE:
 527         {
 528                 const struct lttng_buffer_view probe_attr_view =
 529                                 lttng_buffer_view_from_view(view, offset,
 530                                                 event_comm->lttng_event_probe_attr_len);
 531
 532                 if (event_comm->lttng_event_probe_attr_len == 0) {
 533                         ret = -1;
 534                         goto end;
 535                 }
 536
 537                 if (!lttng_buffer_view_is_valid(&probe_attr_view)) {
 538                         ret = -1;
 539                         goto end;
 540                 }
 541
 542                 ret = lttng_event_probe_attr_create_from_buffer(
 543                                 &probe_attr_view, &local_probe_attr);
 544                 if (ret < 0 || ret != event_comm->lttng_event_probe_attr_len) {
 545                         ret = -1;
 546                         goto end;
 547                 }
 548
 549                 /* Copy to the local event. */
 550                 memcpy(&local_event->attr.probe, local_probe_attr,
 551                                 sizeof(local_event->attr.probe));
 552
 553                 offset += ret;
 554                 break;
 555         }
 556         case LTTNG_EVENT_FUNCTION_ENTRY:
 557         {
 558                 const struct lttng_buffer_view function_attr_view =
 559                                 lttng_buffer_view_from_view(view, offset,
 560                                                 event_comm->lttng_event_function_attr_len);
 561
 562                 if (event_comm->lttng_event_function_attr_len == 0) {
 563                         ret = -1;
 564                         goto end;
 565                 }
 566
 567                 if (!lttng_buffer_view_is_valid(&function_attr_view)) {
 568                         ret = -1;
 569                         goto end;
 570                 }
 571
 572                 ret = lttng_event_function_attr_create_from_buffer(
 573                                 &function_attr_view, &local_function_attr);
 574                 if (ret < 0 || ret != event_comm->lttng_event_function_attr_len) {
 575                         ret = -1;
 576                         goto end;
 577                 }
 578
 579                 /* Copy to the local event. */
 580                 memcpy(&local_event->attr.ftrace, local_function_attr,
 581                                 sizeof(local_event->attr.ftrace));
 582
 583                 offset += ret;
 584
 585                 break;
 586         }
 587         case LTTNG_EVENT_USERSPACE_PROBE:
 588         {
 589                 const struct lttng_buffer_view userspace_probe_location_view =
 590                                 lttng_buffer_view_from_view(view, offset,
 591                                                 event_comm->userspace_probe_location_len);
 592                 const struct lttng_userspace_probe_location_lookup_method
 593                                 *lookup = NULL;
 594
 595                 if (event_comm->userspace_probe_location_len == 0) {
 596                         ret = -1;
 597                         goto end;
 598                 }
 599
 600                 if (!lttng_buffer_view_is_valid(
 601                                     &userspace_probe_location_view)) {
 602                         ret = -1;
 603                         goto end;
 604                 }
 605
 606                 ret = lttng_userspace_probe_location_create_from_buffer(
 607                                 &userspace_probe_location_view,
 608                                 &local_userspace_probe_location);
 609                 if (ret < 0) {
 610                         WARN("Failed to create a userspace probe location from the received buffer");
 611                         ret = -1;
 612                         goto end;
 613                 }
 614
 615                 if (ret != event_comm->userspace_probe_location_len) {
 616                         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);
 617                         ret = -1;
 618                         goto end;
 619                 }
 620
 621                 if (sock < 0) {
 622                         /*
 623                          * The userspace FD is simply not sent and we do not
 624                          * care about it. This happens on listing.
 625                          */
 626                         goto attach_userspace_probe_to_event;
 627                 }
 628
 629                 /*
 630                  * Receive the file descriptor to the target binary from the
 631                  * client.
 632                  */
 633                 DBG("Receiving userspace probe target FD from client ...");
 634                 ret = lttcomm_recv_fds_unix_sock(sock, &received_fd, 1);
 635                 if (ret <= 0) {
 636                         DBG("Nothing recv() from client userspace probe fd... continuing");
 637                         ret = -1;
 638                         goto end;
 639                 }
 640                 /*
 641                  * Set the file descriptor received from the client through the
 642                  * unix socket in the probe location.
 643                  */
 644                 lookup = lttng_userspace_probe_location_get_lookup_method(
 645                                 local_userspace_probe_location);
 646                 if (!lookup) {
 647                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 648                         goto end;
 649                 }
 650
 651                 /*
 652                  * From the kernel tracer's perspective, all userspace probe
 653                  * event types are all the same: a file and an offset.
 654                  */
 655                 switch (lttng_userspace_probe_location_lookup_method_get_type(
 656                                 lookup)) {
 657                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
 658                         ret = lttng_userspace_probe_location_function_set_binary_fd(
 659                                         local_userspace_probe_location,
 660                                         received_fd);
 661                         break;
 662                 case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
 663                         ret = lttng_userspace_probe_location_tracepoint_set_binary_fd(
 664                                         local_userspace_probe_location,
 665                                         received_fd);
 666                         break;
 667                 default:
 668                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 669                         goto end;
 670                 }
 671
 672                 if (ret) {
 673                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 674                         goto end;
 675                 }
 676
 677                 /* Fd transfered to the object. */
 678                 received_fd = -1;
 679
 680 attach_userspace_probe_to_event:
 681
 682                 /* Attach the probe location to the event. */
 683                 ret = lttng_event_set_userspace_probe_location(
 684                                 local_event, local_userspace_probe_location);
 685                 if (ret) {
 686                         ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
 687                         goto end;
 688                 }
 689
 690                 /*
 691                  * Userspace probe location object ownership transfered to the
 692                  * event object
 693                  */
 694                 local_userspace_probe_location = NULL;
 695                 offset += event_comm->userspace_probe_location_len;
 696                 break;
 697         }
 698         case LTTNG_EVENT_TRACEPOINT:
 699                 /* Fallthrough */
 700         case LTTNG_EVENT_ALL:
 701                 /* Fallthrough */
 702         case LTTNG_EVENT_SYSCALL:
 703                 /* Fallthrough */
 704         case LTTNG_EVENT_NOOP:
 705                 /* Nothing to do here */
 706                 break;
 707         default:
 708                 ret = LTTNG_ERR_UND;
 709                 goto end;
 710                 break;
 711         }
 712
 713         /* Transfer ownership to the caller. */
 714         *event = local_event;
 715         local_event = NULL;
 716
 717         if (bytecode) {
 718                 *bytecode = local_bytecode;
 719                 local_bytecode = NULL;
 720         }
 721
 722         if (exclusion) {
 723                 *exclusion = local_exclusions;
 724                 local_exclusions = NULL;
 725         }
 726
 727         if (filter_expression) {
 728                 *filter_expression = local_filter_expression;
 729                 local_filter_expression = NULL;
 730         }
 731
 732         ret = offset;
 733 end:
 734         lttng_event_destroy(local_event);
 735         lttng_userspace_probe_location_destroy(local_userspace_probe_location);
 736         free(local_filter_expression);
 737         free(local_exclusions);
 738         free(local_bytecode);
 739         free(local_function_attr);
 740         free(local_probe_attr);
 741         if (received_fd > -1) {
 742                 if (close(received_fd)) {
 743                         PERROR("Failed to close received fd");
 744                 };
 745         }
 746         return ret;
 747 }
 748
 749 LTTNG_HIDDEN
 750 int lttng_event_serialize(const struct lttng_event *event,
 751                 unsigned int exclusion_count,
 752                 char **exclusion_list,
 753                 char *filter_expression,
 754                 size_t bytecode_len,
 755                 void *bytecode,
 756                 struct lttng_dynamic_buffer *buf,
 757                 int *fd_to_send)
 758 {
 759         int ret;
 760         unsigned int i;
 761         size_t header_offset, size_before_payload;
 762         size_t name_len;
 763         struct lttng_event_comm event_comm = { 0 };
 764         struct lttng_event_comm *header;
 765
 766         assert(event);
 767         assert(buf);
 768
 769         /* Save the header location for later in-place header update. */
 770         header_offset = buf->size;
 771
 772         name_len = lttng_strnlen(event->name, LTTNG_SYMBOL_NAME_LEN);
 773         if (name_len == LTTNG_SYMBOL_NAME_LEN) {
 774                 /* Event name is not NULL-terminated. */
 775                 ret = -1;
 776                 goto end;
 777         }
 778
 779         /* Add null termination. */
 780         name_len += 1;
 781
 782         if (exclusion_count > UINT32_MAX) {
 783                 /* Possible overflow. */
 784                 ret = -1;
 785                 goto end;
 786         }
 787
 788         if (bytecode_len > UINT32_MAX) {
 789                 /* Possible overflow. */
 790                 ret = -1;
 791                 goto end;
 792         }
 793
 794         event_comm.name_len = (uint32_t) name_len;
 795         event_comm.event_type = (int8_t) event->type;
 796         event_comm.loglevel_type = (int8_t) event->loglevel_type;
 797         event_comm.loglevel = (int32_t) event->loglevel;
 798         event_comm.enabled = (int8_t) event->enabled;
 799         event_comm.pid = (int32_t) event->pid;
 800         event_comm.exclusion_count = (uint32_t) exclusion_count;
 801         event_comm.bytecode_len = (uint32_t) bytecode_len;
 802         event_comm.flags = (int32_t) event->flags;
 803
 804         if (filter_expression) {
 805                 event_comm.filter_expression_len =
 806                                 strlen(filter_expression) + 1;
 807         }
 808
 809         /* Header */
 810         ret = lttng_dynamic_buffer_append(buf, &event_comm, sizeof(event_comm));
 811         if (ret) {
 812                 goto end;
 813         }
 814
 815         /* Event name */
 816         ret = lttng_dynamic_buffer_append(buf, event->name, name_len);
 817         if (ret) {
 818                 goto end;
 819         }
 820
 821         /* Exclusions */
 822         for (i = 0; i < exclusion_count; i++) {
 823                 size_t exclusion_len;
 824                 struct lttng_event_exclusion_comm exclusion_comm = { 0 };
 825
 826                 assert(exclusion_list);
 827
 828                 exclusion_len = lttng_strnlen(
 829                                 *(exclusion_list + i), LTTNG_SYMBOL_NAME_LEN);
 830                 if (exclusion_len == LTTNG_SYMBOL_NAME_LEN) {
 831                         /* Exclusion is not NULL-terminated. */
 832                         ret = -1;
 833                         goto end;
 834                 }
 835
 836                 /* Include null terminator '\0'. */
 837                 exclusion_len += 1;
 838
 839                 exclusion_comm.len = exclusion_len;
 840
 841                 ret = lttng_dynamic_buffer_append(buf, &exclusion_comm, sizeof(exclusion_comm));
 842                 if (ret) {
 843                         goto end;
 844                 }
 845
 846                 ret = lttng_dynamic_buffer_append(buf, *(exclusion_list + i),
 847                                 exclusion_len);
 848                 if (ret) {
 849                         goto end;
 850                 }
 851         }
 852
 853         /* Filter expression and its bytecode */
 854         if (filter_expression) {
 855                 ret = lttng_dynamic_buffer_append(buf, filter_expression,
 856                                 event_comm.filter_expression_len);
 857                 if (ret) {
 858                         goto end;
 859                 }
 860
 861                 /*
 862                  * Bytecode can be absent when we serialize to the client
 863                  * for listing.
 864                  */
 865                 if (bytecode) {
 866                         ret = lttng_dynamic_buffer_append(
 867                                         buf, bytecode, bytecode_len);
 868                         if (ret) {
 869                                 goto end;
 870                         }
 871                 }
 872         }
 873
 874         size_before_payload = buf->size;
 875
 876         /* Event type specific payload */
 877         switch (event->type) {
 878         case LTTNG_EVENT_FUNCTION:
 879                 /* Fallthrough */
 880         case LTTNG_EVENT_PROBE:
 881                 ret = lttng_event_probe_attr_serialize(&event->attr.probe, buf);
 882                 if (ret) {
 883                         ret = -1;
 884                         goto end;
 885                 }
 886
 887                 header = (struct lttng_event_comm *) ((char *) buf->data +
 888                                                       header_offset);
 889                 header->lttng_event_probe_attr_len =
 890                                 buf->size - size_before_payload;
 891
 892                 break;
 893         case LTTNG_EVENT_FUNCTION_ENTRY:
 894                 ret = lttng_event_function_attr_serialize(
 895                                 &event->attr.ftrace, buf);
 896                 if (ret) {
 897                         ret = -1;
 898                         goto end;
 899                 }
 900
 901                 /* Update the lttng_event_function_attr len. */
 902                 header = (struct lttng_event_comm *) ((char *) buf->data +
 903                                                       header_offset);
 904                 header->lttng_event_function_attr_len =
 905                                 buf->size - size_before_payload;
 906
 907                 break;
 908         case LTTNG_EVENT_USERSPACE_PROBE:
 909         {
 910                 struct lttng_event_extended *ev_ext =
 911                                 (struct lttng_event_extended *)
 912                                                 event->extended.ptr;
 913                 assert(event->extended.ptr);
 914                 assert(ev_ext->probe_location);
 915
 916                 size_before_payload = buf->size;
 917                 if (ev_ext->probe_location) {
 918                         /*
 919                          * lttng_userspace_probe_location_serialize returns the
 920                          * number of bytes that were appended to the buffer.
 921                          */
 922                         ret = lttng_userspace_probe_location_serialize(
 923                                         ev_ext->probe_location, buf,
 924                                         fd_to_send);
 925                         if (ret < 0) {
 926                                 goto end;
 927                         }
 928                         ret = 0;
 929
 930                         /* Update the userspace probe location len. */
 931                         header = (struct lttng_event_comm *) ((char *) buf->data +
 932                                                               header_offset);
 933                         header->userspace_probe_location_len =
 934                                         buf->size - size_before_payload;
 935                 }
 936                 break;
 937         }
 938         case LTTNG_EVENT_TRACEPOINT:
 939                 /* Fallthrough */
 940         case LTTNG_EVENT_ALL:
 941                 /* Fallthrough */
 942         default:
 943                 /* Nothing to do here */
 944                 break;
 945         }
 946
 947 end:
 948         return ret;
 949 }
 950
 951 static ssize_t lttng_event_context_app_populate_from_buffer(
 952                 const struct lttng_buffer_view *view,
 953                 struct lttng_event_context *event_ctx)
 954 {
 955         ssize_t ret, offset = 0;
 956         const struct lttng_event_context_app_comm *comm;
 957         char *provider_name = NULL, *context_name = NULL;
 958         size_t provider_name_len, context_name_len;
 959         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
 960                         view, offset, sizeof(*comm));
 961
 962         assert(event_ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
 963
 964         if (!lttng_buffer_view_is_valid(&comm_view)) {
 965                 ret = -1;
 966                 goto end;
 967         }
 968
 969         comm = (typeof(comm)) comm_view.data;
 970         offset += sizeof(*comm);
 971
 972         provider_name_len = comm->provider_name_len;
 973         context_name_len = comm->ctx_name_len;
 974
 975         if (provider_name_len == 0 || context_name_len == 0) {
 976                 /*
 977                  * Application provider and context names MUST
 978                  * be provided.
 979                  */
 980                 ret = -1;
 981                 goto end;
 982         }
 983
 984         {
 985                 const char *name;
 986                 const struct lttng_buffer_view provider_name_view =
 987                                 lttng_buffer_view_from_view(view, offset,
 988                                                 provider_name_len);
 989
 990                 if (!lttng_buffer_view_is_valid(&provider_name_view)) {
 991                         ret = -1;
 992                         goto end;
 993                 }
 994
 995                 name = provider_name_view.data;
 996
 997                 if (!lttng_buffer_view_contains_string(&provider_name_view,
 998                                     name, provider_name_len)) {
 999                         ret = -1;
1000                         goto end;
1001                 }
1002
1003                 provider_name = lttng_strndup(name, provider_name_len);
1004                 if (!provider_name) {
1005                         ret = -1;
1006                         goto end;
1007                 }
1008                 offset += provider_name_len;
1009         }
1010
1011         {
1012                 const char *name;
1013                 const struct lttng_buffer_view context_name_view =
1014                                 lttng_buffer_view_from_view(
1015                                                 view, offset, context_name_len);
1016
1017                 if (!lttng_buffer_view_is_valid(&context_name_view)) {
1018                         ret = -1;
1019                         goto end;
1020                 }
1021
1022                 name = context_name_view.data;
1023
1024                 if (!lttng_buffer_view_contains_string(&context_name_view, name,
1025                                     context_name_len)) {
1026                         ret = -1;
1027                         goto end;
1028                 }
1029
1030                 context_name = lttng_strndup(name, context_name_len);
1031                 if (!context_name) {
1032                         ret = -1;
1033                         goto end;
1034                 }
1035
1036                 offset += context_name_len;
1037         }
1038
1039         /* Transfer ownership of the strings */
1040         event_ctx->u.app_ctx.provider_name = provider_name;
1041         event_ctx->u.app_ctx.ctx_name = context_name;
1042         provider_name = NULL;
1043         context_name = NULL;
1044
1045         ret = offset;
1046 end:
1047         free(provider_name);
1048         free(context_name);
1049
1050         return ret;
1051 }
1052
1053 static ssize_t lttng_event_context_perf_counter_populate_from_buffer(
1054                 const struct lttng_buffer_view *view,
1055                 struct lttng_event_context *event_ctx)
1056 {
1057         int ret;
1058         ssize_t consumed, offset = 0;
1059         const struct lttng_event_context_perf_counter_comm *comm;
1060         size_t name_len;
1061         const struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
1062                         view, offset, sizeof(*comm));
1063
1064         assert(event_ctx->ctx == LTTNG_EVENT_CONTEXT_PERF_COUNTER ||
1065                         event_ctx->ctx ==
1066                                         LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER ||
1067                         event_ctx->ctx == LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER);
1068
1069         if (!lttng_buffer_view_is_valid(&comm_view)) {
1070                 consumed = -1;
1071                 goto end;
1072         }
1073
1074         comm = (typeof(comm)) comm_view.data;
1075         offset += sizeof(*comm);
1076
1077         name_len = comm->name_len;
1078         {
1079                 const char *name;
1080                 const struct lttng_buffer_view provider_name_view =
1081                                 lttng_buffer_view_from_view(
1082                                                 view, offset, name_len);
1083                 if (!lttng_buffer_view_is_valid(&provider_name_view)) {
1084                         consumed = -1;
1085                         goto end;
1086                 }
1087
1088                 name = provider_name_view.data;
1089
1090                 if (!lttng_buffer_view_contains_string(
1091                                     &provider_name_view, name, name_len)) {
1092                         consumed = -1;
1093                         goto end;
1094                 }
1095
1096                 ret = lttng_strncpy(event_ctx->u.perf_counter.name, name, name_len);
1097                 if (ret) {
1098                         consumed = -1;
1099                         goto end;
1100                 }
1101                 offset += name_len;
1102         }
1103
1104         event_ctx->u.perf_counter.config = comm->config;
1105         event_ctx->u.perf_counter.type = comm->type;
1106
1107         consumed = offset;
1108
1109 end:
1110         return consumed;
1111 }
1112
1113 LTTNG_HIDDEN
1114 ssize_t lttng_event_context_create_from_buffer(
1115                 const struct lttng_buffer_view *view,
1116                 struct lttng_event_context **event_ctx)
1117 {
1118         ssize_t ret, offset = 0;
1119         const struct lttng_event_context_comm *comm;
1120         struct lttng_event_context *local_context = NULL;
1121         struct lttng_buffer_view subtype_view;
1122         struct lttng_buffer_view comm_view = lttng_buffer_view_from_view(
1123                         view, offset, sizeof(*comm));
1124
1125         assert(event_ctx);
1126         assert(view);
1127
1128         if (!lttng_buffer_view_is_valid(&comm_view)) {
1129                 ret = -1;
1130                 goto end;
1131         }
1132
1133         comm = (typeof(comm)) comm_view.data;
1134         offset += sizeof(*comm);
1135
1136         local_context = zmalloc(sizeof(*local_context));
1137         if (!local_context) {
1138                 ret = -1;
1139                 goto end;
1140         }
1141
1142         local_context->ctx = comm->type;
1143
1144         subtype_view = lttng_buffer_view_from_view(view, offset, -1);
1145
1146         switch (local_context->ctx) {
1147         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1148                 ret = lttng_event_context_app_populate_from_buffer(
1149                                 &subtype_view, local_context);
1150                 break;
1151         case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1152         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1153         case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1154                 ret = lttng_event_context_perf_counter_populate_from_buffer(
1155                                 &subtype_view, local_context);
1156                 break;
1157         default:
1158                 /* Nothing else to deserialize. */
1159                 ret = 0;
1160                 break;
1161         }
1162
1163         if (ret < 0) {
1164                 goto end;
1165         }
1166
1167         offset += ret;
1168
1169         *event_ctx = local_context;
1170         local_context = NULL;
1171         ret = offset;
1172
1173 end:
1174         free(local_context);
1175         return ret;
1176 }
1177
1178 static int lttng_event_context_app_serialize(
1179                 struct lttng_event_context *context,
1180                 struct lttng_dynamic_buffer *buffer)
1181 {
1182         int ret;
1183         struct lttng_event_context_app_comm comm = { 0 };
1184         size_t provider_len, ctx_len;
1185         const char *provider_name;
1186         const char *ctx_name;
1187
1188         assert(buffer);
1189         assert(context);
1190         assert(context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
1191
1192         provider_name = context->u.app_ctx.provider_name;
1193         ctx_name = context->u.app_ctx.ctx_name;
1194
1195         if (!provider_name || !ctx_name) {
1196                 ret = -LTTNG_ERR_INVALID;
1197                 goto end;
1198         }
1199
1200         provider_len = strlen(provider_name);
1201         if (provider_len == 0) {
1202                 ret = -LTTNG_ERR_INVALID;
1203                 goto end;
1204         }
1205
1206         /* Include the null terminator. */
1207         provider_len += 1;
1208         comm.provider_name_len = provider_len;
1209
1210         ctx_len = strlen(ctx_name);
1211         if (ctx_len == 0) {
1212                 ret = -LTTNG_ERR_INVALID;
1213                 goto end;
1214         }
1215
1216         /* Include the null terminator. */
1217         ctx_len += 1;
1218         comm.ctx_name_len = ctx_len;
1219
1220         /* Header */
1221         ret = lttng_dynamic_buffer_append(buffer, &comm, sizeof(comm));
1222         if (ret) {
1223                 ret = -1;
1224                 goto end;
1225         }
1226
1227         ret = lttng_dynamic_buffer_append(buffer, provider_name, provider_len);
1228         if (ret) {
1229                 ret = -1;
1230                 goto end;
1231         }
1232         ret = lttng_dynamic_buffer_append(buffer, ctx_name, ctx_len);
1233         if (ret) {
1234                 ret = -1;
1235                 goto end;
1236         }
1237
1238 end:
1239         return ret;
1240 }
1241
1242 static int lttng_event_context_perf_counter_serialize(
1243                 struct lttng_event_perf_counter_ctx *context,
1244                 struct lttng_dynamic_buffer *buffer)
1245 {
1246         int ret;
1247         struct lttng_event_context_perf_counter_comm comm = { 0 };
1248
1249         assert(buffer);
1250         assert(context);
1251
1252         comm.config = context->config;
1253         comm.type = context->type;
1254         comm.name_len = lttng_strnlen(context->name, LTTNG_SYMBOL_NAME_LEN);
1255
1256         if (comm.name_len == LTTNG_SYMBOL_NAME_LEN) {
1257                 ret = -1;
1258                 goto end;
1259         }
1260
1261         /* Include the null terminator. */
1262         comm.name_len += 1;
1263
1264         /* Header */
1265         ret = lttng_dynamic_buffer_append(buffer, &comm, sizeof(comm));
1266         if (ret) {
1267                 ret = -1;
1268                 goto end;
1269         }
1270
1271         ret = lttng_dynamic_buffer_append(buffer, context->name, comm.name_len);
1272         if (ret) {
1273                 ret = -1;
1274                 goto end;
1275         }
1276
1277 end:
1278         return ret;
1279 }
1280
1281 LTTNG_HIDDEN
1282 int lttng_event_context_serialize(struct lttng_event_context *context,
1283                 struct lttng_dynamic_buffer *buf)
1284 {
1285         int ret;
1286         struct lttng_event_context_comm context_comm = { 0 };
1287
1288         assert(context);
1289         assert(buf);
1290
1291         context_comm.type = (uint32_t) context->ctx;
1292
1293         /* Header */
1294         ret = lttng_dynamic_buffer_append(
1295                         buf, &context_comm, sizeof(context_comm));
1296         if (ret) {
1297                 goto end;
1298         }
1299
1300         switch (context->ctx) {
1301         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
1302                 ret = lttng_event_context_app_serialize(context, buf);
1303                 break;
1304         case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
1305         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
1306         case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
1307                 ret = lttng_event_context_perf_counter_serialize(
1308                                 &context->u.perf_counter, buf);
1309                 break;
1310         default:
1311                 /* Nothing else to serialize. */
1312                 break;
1313         }
1314
1315         if (ret) {
1316                 goto end;
1317         }
1318
1319 end:
1320         return ret;
1321 }
1322
1323 LTTNG_HIDDEN
1324 void lttng_event_context_destroy(struct lttng_event_context *context)
1325 {
1326         if (!context) {
1327                 return;
1328         }
1329
1330         if (context->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
1331                 free(context->u.app_ctx.provider_name);
1332                 free(context->u.app_ctx.ctx_name);
1333         }
1334
1335         free(context);
1336 }
1337
1338 /*
1339  * This is a specialized populate for lttng_event_field since it ignores
1340  * the extension field of the lttng_event struct and simply copies what it can
1341  * to the internal struct lttng_event of a lttng_event_field.
1342  */
1343 static void lttng_event_field_populate_lttng_event_from_event(
1344                 const struct lttng_event *src, struct lttng_event *destination)
1345 {
1346         memcpy(destination, src, sizeof(*destination));
1347
1348         /* Remove all possible dynamic data from the destination event rule. */
1349         destination->extended.ptr = NULL;
1350 }
1351
1352 LTTNG_HIDDEN
1353 ssize_t lttng_event_field_create_from_buffer(
1354                 const struct lttng_buffer_view *view,
1355                 struct lttng_event_field **field)
1356 {
1357         ssize_t ret, offset = 0;
1358         struct lttng_event_field *local_event_field = NULL;
1359         struct lttng_event *event = NULL;
1360         const struct lttng_event_field_comm *comm;
1361         const char* name = NULL;
1362
1363         assert(field);
1364         assert(view);
1365
1366         {
1367                 const struct lttng_buffer_view comm_view =
1368                                 lttng_buffer_view_from_view(
1369                                                 view, offset, sizeof(*comm));
1370
1371                 if (!lttng_buffer_view_is_valid(&comm_view)) {
1372                         ret = -1;
1373                         goto end;
1374                 }
1375                 /* lttng_event_field_comm header */
1376                 comm = (const struct lttng_event_field_comm *) view->data;
1377                 offset += sizeof(*comm);
1378         }
1379
1380         local_event_field = zmalloc(sizeof(*local_event_field));
1381         if (!local_event_field) {
1382                 ret = -1;
1383                 goto end;
1384         }
1385
1386         local_event_field->type = comm->type;
1387         local_event_field->nowrite = comm->nowrite;
1388
1389         /* Field name */
1390         {
1391                 const struct lttng_buffer_view name_view =
1392                                 lttng_buffer_view_from_view(
1393                                                 view, offset, comm->name_len);
1394
1395                 if (!lttng_buffer_view_is_valid(&name_view)) {
1396                         ret = -1;
1397                         goto end;
1398                 }
1399
1400                 name = name_view.data;
1401
1402                 if (!lttng_buffer_view_contains_string(&name_view, name_view.data, comm->name_len)) {
1403                         ret = -1;
1404                         goto end;
1405                 }
1406
1407                 if (comm->name_len > LTTNG_SYMBOL_NAME_LEN - 1) {
1408                         /* Name is too long.*/
1409                         ret = -1;
1410                         goto end;
1411                 }
1412                 offset += comm->name_len;
1413         }
1414
1415         /* Event */
1416         {
1417                 const struct lttng_buffer_view event_view =
1418                                 lttng_buffer_view_from_view(
1419                                                 view, offset, comm->event_len);
1420
1421                 if (!lttng_buffer_view_is_valid(&event_view)) {
1422                         ret = -1;
1423                         goto end;
1424                 }
1425                 ret = lttng_event_create_from_buffer(&event_view, &event, NULL,
1426                                 NULL, NULL, -1);
1427                 if (ret != comm->event_len) {
1428                         abort();
1429                 }
1430                 offset += ret;
1431         }
1432
1433         assert(name);
1434         assert(event);
1435
1436         if (lttng_strncpy(local_event_field->field_name, name , LTTNG_SYMBOL_NAME_LEN)) {
1437                 ret = -1;
1438                 goto end;
1439         }
1440
1441         lttng_event_field_populate_lttng_event_from_event(
1442                         event, &local_event_field->event);
1443
1444         *field = local_event_field;
1445         local_event_field = NULL;
1446         ret = offset;
1447 end:
1448         lttng_event_destroy(event);
1449         free(local_event_field);
1450         return ret;
1451 }
1452
1453 LTTNG_HIDDEN
1454 int lttng_event_field_serialize(const struct lttng_event_field *field,
1455                 struct lttng_dynamic_buffer *buffer)
1456 {
1457         int ret;
1458         size_t header_offset, size_before_event;
1459         size_t name_len;
1460         struct lttng_event_field_comm event_field_comm = { 0 };
1461         struct lttng_event_field_comm *header;
1462
1463         assert(field);
1464         assert(buffer);
1465
1466         /* Save the header location for later in-place header update. */
1467         header_offset = buffer->size;
1468
1469         name_len = strnlen(field->field_name, LTTNG_SYMBOL_NAME_LEN);
1470         if (name_len == LTTNG_SYMBOL_NAME_LEN) {
1471                 /* Event name is not NULL-terminated. */
1472                 ret = -1;
1473                 goto end;
1474         }
1475
1476         /* Add null termination. */
1477         name_len += 1;
1478
1479         event_field_comm.type = field->type;
1480         event_field_comm.nowrite = (uint8_t)field->nowrite;
1481         event_field_comm.name_len = name_len;
1482
1483         /* Header */
1484         ret = lttng_dynamic_buffer_append(
1485                         buffer, &event_field_comm, sizeof(event_field_comm));
1486         if (ret) {
1487                 goto end;
1488         }
1489
1490         /* Field name */
1491         ret = lttng_dynamic_buffer_append(buffer, field->field_name, name_len);
1492         if (ret) {
1493                 goto end;
1494         }
1495
1496         size_before_event = buffer->size;
1497         ret = lttng_event_serialize(
1498                         &field->event, 0, NULL, NULL, 0, 0, buffer, NULL);
1499         if (ret) {
1500                 ret = -1;
1501                 goto end;
1502         }
1503
1504         /* Update the event len. */
1505         header = (struct lttng_event_field_comm *) ((char *) buffer->data +
1506                                                     header_offset);
1507         header->event_len = buffer->size - size_before_event;
1508
1509 end:
1510         return ret;
1511 }
1512
1513 static enum lttng_error_code compute_flattened_size(
1514                 struct lttng_dynamic_pointer_array *events, size_t *size)
1515 {
1516         enum lttng_error_code ret_code;
1517         int ret = 0;
1518         size_t storage_req, event_count, i;
1519
1520         assert(size);
1521         assert(events);
1522
1523         event_count = lttng_dynamic_pointer_array_get_count(events);
1524
1525         /* The basic struct lttng_event */
1526         storage_req = event_count * sizeof(struct lttng_event);
1527
1528         /* The struct lttng_event_extended */
1529         storage_req += event_count * sizeof(struct lttng_event_extended);
1530
1531         for (i = 0; i < event_count; i++) {
1532                 int probe_storage_req = 0;
1533                 const struct event_list_element *element =
1534                                 lttng_dynamic_pointer_array_get_pointer(
1535                                                 events, i);
1536                 const struct lttng_userspace_probe_location *location = NULL;
1537
1538                 location = lttng_event_get_userspace_probe_location(
1539                                 element->event);
1540                 if (location) {
1541                         ret = lttng_userspace_probe_location_flatten(
1542                                         location, NULL);
1543                         if (ret < 0) {
1544                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1545                                 goto end;
1546                         }
1547
1548                         probe_storage_req = ret;
1549                 }
1550
1551                 if (element->filter_expression) {
1552                         storage_req += strlen(element->filter_expression) + 1;
1553                 }
1554
1555                 if (element->exclusions) {
1556                         storage_req += element->exclusions->count *
1557                                 LTTNG_SYMBOL_NAME_LEN;
1558                 }
1559
1560                 /* Padding to ensure the flat probe is aligned. */
1561                 storage_req = ALIGN_TO(storage_req, sizeof(uint64_t));
1562                 storage_req += probe_storage_req;
1563         }
1564
1565         *size = storage_req;
1566         ret_code = LTTNG_OK;
1567
1568 end:
1569         return ret_code;
1570 }
1571
1572 /*
1573  * Flatten a list of struct lttng_event.
1574  *
1575  * The buffer that is returned to the API client  must contain a "flat" version
1576  * of the events that are returned. In other words, all pointers within an
1577  * lttng_event must point to a location within the returned buffer so that the
1578  * user may free everything by simply calling free() on the returned buffer.
1579  * This is needed in order to maintain API compatibility.
1580  *
1581  * A first pass is performed to compute the size of the buffer that must be
1582  * allocated. A second pass is then performed to setup the returned events so
1583  * that their members always point within the buffer.
1584  *
1585  * The layout of the returned buffer is as follows:
1586  *   - struct lttng_event[nb_events],
1587  *   - nb_events times the following:
1588  *     - struct lttng_event_extended,
1589  *     - filter_expression
1590  *     - exclusions
1591  *     - padding to align to 64-bits
1592  *     - flattened version of userspace_probe_location
1593  */
1594 static enum lttng_error_code flatten_lttng_events(
1595                 struct lttng_dynamic_pointer_array *events,
1596                 struct lttng_event **flattened_events)
1597 {
1598         enum lttng_error_code ret_code;
1599         int ret, i;
1600         size_t storage_req;
1601         struct lttng_dynamic_buffer local_flattened_events;
1602         int nb_events;
1603
1604         assert(events);
1605         assert(flattened_events);
1606
1607         lttng_dynamic_buffer_init(&local_flattened_events);
1608         nb_events = lttng_dynamic_pointer_array_get_count(events);
1609
1610         ret_code = compute_flattened_size(events, &storage_req);
1611         if (ret_code != LTTNG_OK) {
1612                 goto end;
1613         }
1614
1615         /*
1616          * We must ensure that "local_flattened_events" is never resized so as
1617          * to preserve the validity of the flattened objects.
1618          */
1619         ret = lttng_dynamic_buffer_set_capacity(
1620                         &local_flattened_events, storage_req);
1621         if (ret) {
1622                 ret_code = LTTNG_ERR_NOMEM;
1623                 goto end;
1624         }
1625
1626         /* Start by laying the struct lttng_event */
1627         for (i = 0; i < nb_events; i++) {
1628                 struct event_list_element *element =
1629                                 lttng_dynamic_pointer_array_get_pointer(
1630                                                 events, i);
1631
1632                 if (!element) {
1633                         ret_code = LTTNG_ERR_FATAL;
1634                         goto end;
1635                 }
1636                 ret = lttng_dynamic_buffer_append(&local_flattened_events,
1637                                 element->event, sizeof(struct lttng_event));
1638                 if (ret) {
1639                         ret_code = LTTNG_ERR_NOMEM;
1640                         goto end;
1641                 }
1642         }
1643
1644         for (i = 0; i < nb_events; i++) {
1645                 struct event_list_element *element = lttng_dynamic_pointer_array_get_pointer(events, i);
1646                 struct lttng_event *event = (struct lttng_event *)
1647                         (local_flattened_events.data + (sizeof(struct lttng_event) * i));
1648                 struct lttng_event_extended *event_extended =
1649                         (struct lttng_event_extended *)
1650                                 (local_flattened_events.data + local_flattened_events.size);
1651                 const struct lttng_userspace_probe_location *location = NULL;
1652
1653                 assert(element);
1654
1655                 /* Insert struct lttng_event_extended. */
1656                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1657                                 local_flattened_events.size +
1658                                                 sizeof(*event_extended));
1659                 if (ret) {
1660                         ret_code = LTTNG_ERR_NOMEM;
1661                         goto end;
1662                 }
1663                 event->extended.ptr = event_extended;
1664
1665                 /* Insert filter expression. */
1666                 if (element->filter_expression) {
1667                         size_t len = strlen(element->filter_expression) + 1;
1668
1669                         event_extended->filter_expression =
1670                                         local_flattened_events.data +
1671                                         local_flattened_events.size;
1672                         ret = lttng_dynamic_buffer_append(
1673                                         &local_flattened_events,
1674                                         element->filter_expression, len);
1675                         if (ret) {
1676                                 ret_code = LTTNG_ERR_NOMEM;
1677                                 goto end;
1678                         }
1679                 }
1680
1681                 /* Insert exclusions. */
1682                 if (element->exclusions) {
1683                         event_extended->exclusions.count =
1684                                         element->exclusions->count;
1685                         event_extended->exclusions.strings =
1686                                         local_flattened_events.data +
1687                                         local_flattened_events.size;
1688
1689                         ret = lttng_dynamic_buffer_append(
1690                                         &local_flattened_events,
1691                                         element->exclusions->names,
1692                                         element->exclusions->count *
1693                                                         LTTNG_SYMBOL_NAME_LEN);
1694                         if (ret) {
1695                                 ret_code = LTTNG_ERR_NOMEM;
1696                                 goto end;
1697                         }
1698                 }
1699
1700                 /* Insert padding to align to 64-bits. */
1701                 ret = lttng_dynamic_buffer_set_size(&local_flattened_events,
1702                                 ALIGN_TO(local_flattened_events.size,
1703                                                 sizeof(uint64_t)));
1704                 if (ret) {
1705                         ret_code = LTTNG_ERR_NOMEM;
1706                         goto end;
1707                 }
1708
1709                 location = lttng_event_get_userspace_probe_location(
1710                                 element->event);
1711                 if (location) {
1712                         event_extended->probe_location = (struct lttng_userspace_probe_location *)
1713                                         (local_flattened_events.data + local_flattened_events.size);
1714                         ret = lttng_userspace_probe_location_flatten(
1715                                         location, &local_flattened_events);
1716                         if (ret < 0) {
1717                                 ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
1718                                 goto end;
1719                         }
1720                 }
1721         }
1722
1723         /* Don't reset local_flattened_events buffer as we return its content. */
1724         *flattened_events = (struct lttng_event *) local_flattened_events.data;
1725         lttng_dynamic_buffer_init(&local_flattened_events);
1726         ret_code = LTTNG_OK;
1727 end:
1728         lttng_dynamic_buffer_reset(&local_flattened_events);
1729         return ret_code;
1730 }
1731
1732 static enum lttng_error_code event_list_create_from_buffer(
1733                 const struct lttng_buffer_view *view,
1734                 unsigned int count,
1735                 struct lttng_dynamic_pointer_array *event_list)
1736 {
1737         enum lttng_error_code ret_code;
1738         int ret;
1739         unsigned int i;
1740         int offset = 0;
1741
1742         assert(view);
1743         assert(event_list);
1744
1745         for (i = 0; i < count; i++) {
1746                 ssize_t event_size;
1747                 const struct lttng_buffer_view event_view =
1748                                 lttng_buffer_view_from_view(view, offset, -1);
1749                 struct event_list_element *element = zmalloc(sizeof(*element));
1750
1751                 if (!element) {
1752                         ret_code = LTTNG_ERR_NOMEM;
1753                         goto end;
1754                 }
1755
1756                 /*
1757                  * Lifetime and management of the object is now bound to the
1758                  * array.
1759                  */
1760                 ret = lttng_dynamic_pointer_array_add_pointer(
1761                                 event_list, element);
1762                 if (ret) {
1763                         event_list_destructor(element);
1764                         ret_code = LTTNG_ERR_NOMEM;
1765                         goto end;
1766                 }
1767
1768                 /*
1769                  * Bytecode is not transmitted on listing in any case we do not
1770                  * care about it.
1771                  */
1772                 event_size = lttng_event_create_from_buffer(&event_view,
1773                                 &element->event,
1774                                 &element->exclusions,
1775                                 &element->filter_expression, NULL, -1);
1776                 if (event_size < 0) {
1777                         ret_code = LTTNG_ERR_INVALID;
1778                         goto end;
1779                 }
1780
1781                 offset += event_size;
1782         }
1783
1784         if (view->size != offset) {
1785                 ret_code = LTTNG_ERR_INVALID;
1786                 goto end;
1787         }
1788
1789         ret_code = LTTNG_OK;
1790
1791 end:
1792         return ret_code;
1793 }
1794
1795 LTTNG_HIDDEN
1796 enum lttng_error_code lttng_events_create_and_flatten_from_buffer(
1797                 const struct lttng_buffer_view *view,
1798                 unsigned int count,
1799                 struct lttng_event **events)
1800 {
1801         enum lttng_error_code ret = LTTNG_OK;
1802         struct lttng_dynamic_pointer_array local_events;
1803
1804         lttng_dynamic_pointer_array_init(&local_events, event_list_destructor);
1805
1806         /* Deserialize the events */
1807         {
1808                 const struct lttng_buffer_view events_view =
1809                                 lttng_buffer_view_from_view(view, 0, -1);
1810
1811                 ret = event_list_create_from_buffer(
1812                                 &events_view, count, &local_events);
1813                 if (ret != LTTNG_OK) {
1814                         goto end;
1815                 }
1816         }
1817
1818         ret = flatten_lttng_events(&local_events, events);
1819         if (ret != LTTNG_OK) {
1820                 goto end;
1821         }
1822
1823 end:
1824         lttng_dynamic_pointer_array_reset(&local_events);
1825         return ret;
1826 }
1827
1828 static enum lttng_error_code flatten_lttng_event_fields(
1829                 struct lttng_dynamic_pointer_array *event_fields,
1830                 struct lttng_event_field **flattened_event_fields)
1831 {
1832         int ret, i;
1833         enum lttng_error_code ret_code;
1834         size_t storage_req = 0;
1835         struct lttng_dynamic_buffer local_flattened_event_fields;
1836         int nb_event_field;
1837
1838         assert(event_fields);
1839         assert(flattened_event_fields);
1840
1841         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1842         nb_event_field = lttng_dynamic_pointer_array_get_count(event_fields);
1843
1844         /*
1845          * Here even if the event field contains a `struct lttng_event` that
1846          * could contain dynamic data, in reality it is not the case.
1847          * Dynamic data is not present. Here the flattening is mostly a direct
1848          * memcpy. This is less than ideal but this code is still better than
1849          * direct usage of an unpacked lttng_event_field array.
1850          */
1851         storage_req += sizeof(struct lttng_event_field) * nb_event_field;
1852
1853         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1854
1855         /*
1856          * We must ensure that "local_flattened_event_fields" is never resized
1857          * so as to preserve the validity of the flattened objects.
1858          */
1859         ret = lttng_dynamic_buffer_set_capacity(
1860                         &local_flattened_event_fields, storage_req);
1861         if (ret) {
1862                 ret_code = LTTNG_ERR_NOMEM;
1863                 goto end;
1864         }
1865
1866         for (i = 0; i < nb_event_field; i++) {
1867                 const struct lttng_event_field *element =
1868                                 lttng_dynamic_pointer_array_get_pointer(
1869                                                 event_fields, i);
1870
1871                 if (!element) {
1872                         ret_code = LTTNG_ERR_FATAL;
1873                         goto end;
1874                 }
1875                 ret = lttng_dynamic_buffer_append(&local_flattened_event_fields,
1876                                 element, sizeof(struct lttng_event_field));
1877                 if (ret) {
1878                         ret_code = LTTNG_ERR_NOMEM;
1879                         goto end;
1880                 }
1881         }
1882
1883         /* Don't reset local_flattened_channels buffer as we return its content. */
1884         *flattened_event_fields = (struct lttng_event_field *) local_flattened_event_fields.data;
1885         lttng_dynamic_buffer_init(&local_flattened_event_fields);
1886         ret_code = LTTNG_OK;
1887 end:
1888         lttng_dynamic_buffer_reset(&local_flattened_event_fields);
1889         return ret_code;
1890 }
1891
1892 static enum lttng_error_code event_field_list_create_from_buffer(
1893                 const struct lttng_buffer_view *view,
1894                 unsigned int count,
1895                 struct lttng_dynamic_pointer_array **event_field_list)
1896 {
1897         enum lttng_error_code ret_code;
1898         int ret, offset = 0;
1899         unsigned int i;
1900         struct lttng_dynamic_pointer_array *list = NULL;
1901
1902         assert(view);
1903         assert(event_field_list);
1904
1905         list = zmalloc(sizeof(*list));
1906         if (!list) {
1907                 ret_code = LTTNG_ERR_NOMEM;
1908                 goto end;
1909         }
1910
1911         lttng_dynamic_pointer_array_init(list, free);
1912
1913         for (i = 0; i < count; i++) {
1914                 ssize_t event_field_size;
1915                 struct lttng_event_field *field = NULL;
1916                 const struct lttng_buffer_view event_field_view =
1917                                 lttng_buffer_view_from_view(view, offset, -1);
1918
1919                 event_field_size = lttng_event_field_create_from_buffer(
1920                                 &event_field_view, &field);
1921                 if (event_field_size < 0) {
1922                         ret_code = LTTNG_ERR_INVALID;
1923                         goto end;
1924                 }
1925
1926                 /* Lifetime and management of the object is now bound to the array. */
1927                 ret = lttng_dynamic_pointer_array_add_pointer(list, field);
1928                 if (ret) {
1929                         free(field);
1930                         ret_code = LTTNG_ERR_NOMEM;
1931                         goto end;
1932                 }
1933                 offset += event_field_size;
1934         }
1935
1936         if (view->size != offset) {
1937                 ret_code = LTTNG_ERR_INVALID;
1938                 goto end;
1939         }
1940
1941         *event_field_list = list;
1942         list = NULL;
1943         ret_code = LTTNG_OK;
1944
1945 end:
1946         if (list) {
1947                 lttng_dynamic_pointer_array_reset(list);
1948                 free(list);
1949         }
1950         return ret_code;
1951 }
1952
1953 LTTNG_HIDDEN
1954 enum lttng_error_code lttng_event_fields_create_and_flatten_from_buffer(
1955                 const struct lttng_buffer_view *view,
1956                 unsigned int count,
1957                 struct lttng_event_field **fields)
1958 {
1959         enum lttng_error_code ret;
1960         struct lttng_dynamic_pointer_array *local_event_fields = NULL;
1961
1962         ret = event_field_list_create_from_buffer(
1963                         view, count, &local_event_fields);
1964         if (ret != LTTNG_OK) {
1965                 goto end;
1966         }
1967
1968         ret = flatten_lttng_event_fields(local_event_fields, fields);
1969         if (ret != LTTNG_OK) {
1970                 goto end;
1971         }
1972 end:
1973         if (local_event_fields) {
1974                 lttng_dynamic_pointer_array_reset(local_event_fields);
1975                 free(local_event_fields);
1976         }
1977         return ret;
1978 }