src/common/trace-chunk.cpp

   1 /*
   2  * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #include <common/compat/directory-handle.hpp>
   9 #include <common/credentials.hpp>
  10 #include <common/defaults.hpp>
  11 #include <common/dynamic-array.hpp>
  12 #include <common/error.hpp>
  13 #include <common/fd-tracker/fd-tracker.hpp>
  14 #include <common/fd-tracker/utils.hpp>
  15 #include <common/fs-handle.hpp>
  16 #include <common/fs-handle-internal.hpp>
  17 #include <common/hashtable/hashtable.hpp>
  18 #include <common/hashtable/utils.hpp>
  19 #include <common/optional.hpp>
  20 #include <common/string-utils/format.hpp>
  21 #include <common/time.hpp>
  22 #include <common/trace-chunk-registry.hpp>
  23 #include <common/trace-chunk.hpp>
  24 #include <common/utils.hpp>
  25 #include <lttng/constant.h>
  26
  27 #include <inttypes.h>
  28 #include <pthread.h>
  29 #include <stdio.h>
  30 #include <sys/stat.h>
  31 #include <urcu/rculfhash.h>
  32 #include <urcu/ref.h>
  33
  34 /*
  35  * Two ISO 8601-compatible timestamps, separated by a hypen, followed an
  36  * index, i.e. <start-iso-8601>-<end-iso-8601>-<id-uint64_t>.
  37  */
  38 #define GENERATED_CHUNK_NAME_LEN (2 * sizeof("YYYYmmddTHHMMSS+HHMM") + MAX_INT_DEC_LEN(uint64_t))
  39 #define DIR_CREATION_MODE (S_IRWXU | S_IRWXG)
  40
  41 enum trace_chunk_mode {
  42         TRACE_CHUNK_MODE_USER,
  43         TRACE_CHUNK_MODE_OWNER,
  44 };
  45
  46 /*
  47  * Callback to invoke on release of a trace chunk. Note that there is no
  48  * need to 'lock' the trace chunk during the execution of these callbacks
  49  * since only one thread may access a chunk during its destruction (the last
  50  * to release its reference to the chunk).
  51  */
  52 typedef int (*chunk_command)(struct lttng_trace_chunk *trace_chunk);
  53
  54 /* Move a completed trace chunk to the 'completed' trace archive folder. */
  55 static
  56 int lttng_trace_chunk_move_to_completed_post_release(struct lttng_trace_chunk *trace_chunk);
  57 /* Empty callback. */
  58 static
  59 int lttng_trace_chunk_no_operation(struct lttng_trace_chunk *trace_chunk);
  60 /* Unlink old chunk files. */
  61 static
  62 int lttng_trace_chunk_delete_post_release(struct lttng_trace_chunk *trace_chunk);
  63 static
  64 enum lttng_trace_chunk_status lttng_trace_chunk_rename_path_no_lock(
  65                 struct lttng_trace_chunk *chunk, const char *path);
  66
  67 namespace {
  68 struct chunk_credentials {
  69         bool use_current_user;
  70         struct lttng_credentials user;
  71 };
  72 } /* namespace */
  73
  74 /*
  75  * NOTE: Make sure to update:
  76  * - lttng_trace_chunk_copy(),
  77  * - lttng_trace_chunk_registry_element_create_from_chunk()
  78  * if you modify this structure.
  79  */
  80 struct lttng_trace_chunk {
  81         pthread_mutex_t lock;
  82         struct urcu_ref ref;
  83         LTTNG_OPTIONAL(enum trace_chunk_mode) mode;
  84         /*
  85          * First-level directories created within the trace chunk.
  86          * Elements are of type 'char *'.
  87          *
  88          * Only used by _owner_ mode chunks.
  89          */
  90         struct lttng_dynamic_pointer_array top_level_directories;
  91         /*
  92          * All files contained within the trace chunk.
  93          * Array of paths (char *).
  94          */
  95         struct lttng_dynamic_pointer_array files;
  96         /* Is contained within an lttng_trace_chunk_registry_element? */
  97         bool in_registry_element;
  98         bool name_overridden;
  99         char *name;
 100         char *path;
 101         /* An unset id means the chunk is anonymous. */
 102         LTTNG_OPTIONAL(uint64_t) id;
 103
 104         /*
 105          * The creation and close timestamps are NOT monotonic.
 106          * They must not be used in context were monotonicity is required.
 107          */
 108         LTTNG_OPTIONAL(time_t) timestamp_creation;
 109         LTTNG_OPTIONAL(time_t) timestamp_close;
 110
 111         LTTNG_OPTIONAL(struct chunk_credentials) credentials;
 112         struct lttng_directory_handle *session_output_directory;
 113         struct lttng_directory_handle *chunk_directory;
 114         LTTNG_OPTIONAL(enum lttng_trace_chunk_command_type) close_command;
 115         /*
 116          * fd_tracker instance through which file descriptors should be
 117          * created/closed.
 118          *
 119          * An fd_tracker always outlives any trace chunk; there is no
 120          * need to perform any reference counting of that object.
 121          */
 122         struct fd_tracker *fd_tracker;
 123 };
 124
 125 namespace {
 126 /* A trace chunk is uniquely identified by its (session id, chunk id) tuple. */
 127 struct lttng_trace_chunk_registry_element {
 128         struct lttng_trace_chunk chunk;
 129         uint64_t session_id;
 130         /* Weak and only set when added. */
 131         struct lttng_trace_chunk_registry *registry;
 132         struct cds_lfht_node trace_chunk_registry_ht_node;
 133         /* call_rcu delayed reclaim. */
 134         struct rcu_head rcu_node;
 135 };
 136 } /* namespace */
 137
 138 struct lttng_trace_chunk_registry {
 139         struct cds_lfht *ht;
 140 };
 141
 142 namespace {
 143 struct fs_handle_untracked {
 144         struct fs_handle parent;
 145         int fd;
 146         struct {
 147                 struct lttng_directory_handle *directory_handle;
 148                 char *path;
 149         } location;
 150 };
 151 } /* namespace */
 152
 153 static
 154 int fs_handle_untracked_get_fd(struct fs_handle *handle);
 155 static
 156 void fs_handle_untracked_put_fd(struct fs_handle *handle);
 157 static
 158 int fs_handle_untracked_unlink(struct fs_handle *handle);
 159 static
 160 int fs_handle_untracked_close(struct fs_handle *handle);
 161
 162 static
 163 const char *lttng_trace_chunk_command_type_str(
 164                 lttng_trace_chunk_command_type type) {
 165         switch (type) {
 166         case LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED:
 167                 return "move to completed chunk folder";
 168         case LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION:
 169                 return "no operation";
 170         case LTTNG_TRACE_CHUNK_COMMAND_TYPE_DELETE:
 171                 return "delete";
 172         case LTTNG_TRACE_CHUNK_COMMAND_TYPE_MAX:
 173                 abort();
 174         }
 175
 176         abort();
 177 };
 178
 179 static
 180 chunk_command close_command_get_post_release_func(
 181                 lttng_trace_chunk_command_type type) {
 182         switch (type) {
 183         case LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED:
 184                 return lttng_trace_chunk_move_to_completed_post_release;
 185         case LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION:
 186                 return lttng_trace_chunk_no_operation;
 187         case LTTNG_TRACE_CHUNK_COMMAND_TYPE_DELETE:
 188                 return lttng_trace_chunk_delete_post_release;
 189         case LTTNG_TRACE_CHUNK_COMMAND_TYPE_MAX:
 190                 abort();
 191         }
 192
 193         abort();
 194 };
 195
 196 static
 197 struct fs_handle *fs_handle_untracked_create(
 198                 struct lttng_directory_handle *directory_handle,
 199                 const char *path,
 200                 int fd)
 201 {
 202         struct fs_handle_untracked *handle = NULL;
 203         bool reference_acquired;
 204         char *path_copy = strdup(path);
 205
 206         LTTNG_ASSERT(fd >= 0);
 207         if (!path_copy) {
 208                 PERROR("Failed to copy file path while creating untracked filesystem handle");
 209                 goto end;
 210         }
 211
 212         handle = zmalloc<fs_handle_untracked>();
 213         if (!handle) {
 214                 PERROR("Failed to allocate untracked filesystem handle");
 215                 goto end;
 216         }
 217
 218         handle->parent = (typeof(handle->parent)) {
 219                 .get_fd = fs_handle_untracked_get_fd,
 220                 .put_fd = fs_handle_untracked_put_fd,
 221                 .unlink = fs_handle_untracked_unlink,
 222                 .close = fs_handle_untracked_close,
 223         };
 224
 225         handle->fd = fd;
 226         reference_acquired = lttng_directory_handle_get(directory_handle);
 227         LTTNG_ASSERT(reference_acquired);
 228         handle->location.directory_handle = directory_handle;
 229         /* Ownership is transferred. */
 230         handle->location.path = path_copy;
 231         path_copy = NULL;
 232 end:
 233         free(path_copy);
 234         return handle ? &handle->parent : NULL;
 235 }
 236
 237 static
 238 int fs_handle_untracked_get_fd(struct fs_handle *_handle)
 239 {
 240         struct fs_handle_untracked *handle = container_of(
 241                         _handle, struct fs_handle_untracked, parent);
 242
 243         return handle->fd;
 244 }
 245
 246 static
 247 void fs_handle_untracked_put_fd(struct fs_handle *_handle __attribute__((unused)))
 248 {
 249         /* no-op. */
 250 }
 251
 252 static
 253 int fs_handle_untracked_unlink(struct fs_handle *_handle)
 254 {
 255         struct fs_handle_untracked *handle = container_of(
 256                         _handle, struct fs_handle_untracked, parent);
 257
 258         return lttng_directory_handle_unlink_file(
 259                         handle->location.directory_handle,
 260                         handle->location.path);
 261 }
 262
 263 static
 264 void fs_handle_untracked_destroy(struct fs_handle_untracked *handle)
 265 {
 266         lttng_directory_handle_put(handle->location.directory_handle);
 267         free(handle->location.path);
 268         free(handle);
 269 }
 270
 271 static
 272 int fs_handle_untracked_close(struct fs_handle *_handle)
 273 {
 274         struct fs_handle_untracked *handle = container_of(
 275                         _handle, struct fs_handle_untracked, parent);
 276         int ret = close(handle->fd);
 277
 278         fs_handle_untracked_destroy(handle);
 279         return ret;
 280 }
 281
 282 static
 283 bool lttng_trace_chunk_registry_element_equals(
 284                 const struct lttng_trace_chunk_registry_element *a,
 285                 const struct lttng_trace_chunk_registry_element *b)
 286 {
 287         if (a->session_id != b->session_id) {
 288                 goto not_equal;
 289         }
 290         if (a->chunk.id.is_set != b->chunk.id.is_set) {
 291                 goto not_equal;
 292         }
 293         if (a->chunk.id.is_set && a->chunk.id.value != b->chunk.id.value) {
 294                 goto not_equal;
 295         }
 296         return true;
 297 not_equal:
 298         return false;
 299 }
 300
 301 static
 302 int lttng_trace_chunk_registry_element_match(struct cds_lfht_node *node,
 303                 const void *key)
 304 {
 305         const struct lttng_trace_chunk_registry_element *element_a, *element_b;
 306
 307         element_a = (const struct lttng_trace_chunk_registry_element *) key;
 308         element_b = caa_container_of(node, typeof(*element_b),
 309                         trace_chunk_registry_ht_node);
 310         return lttng_trace_chunk_registry_element_equals(element_a, element_b);
 311 }
 312
 313 static
 314 unsigned long lttng_trace_chunk_registry_element_hash(
 315                 const struct lttng_trace_chunk_registry_element *element)
 316 {
 317         unsigned long hash = hash_key_u64(&element->session_id,
 318                         lttng_ht_seed);
 319
 320         if (element->chunk.id.is_set) {
 321                 hash ^= hash_key_u64(&element->chunk.id.value, lttng_ht_seed);
 322         }
 323
 324         return hash;
 325 }
 326
 327 static
 328 char *generate_chunk_name(uint64_t chunk_id, time_t creation_timestamp,
 329                 const time_t *close_timestamp)
 330 {
 331         int ret = 0;
 332         char *new_name= NULL;
 333         char start_datetime[ISO8601_STR_LEN] = {};
 334         /* Add 1 for a '-' prefix. */
 335         char end_datetime_suffix[ISO8601_STR_LEN + 1] = {};
 336
 337         ret = time_to_iso8601_str(
 338                         creation_timestamp,
 339                         start_datetime, sizeof(start_datetime));
 340         if (ret) {
 341                 ERR("Failed to format trace chunk start date time");
 342                 goto error;
 343         }
 344         if (close_timestamp) {
 345                 *end_datetime_suffix = '-';
 346                 ret = time_to_iso8601_str(
 347                                 *close_timestamp,
 348                                 end_datetime_suffix + 1,
 349                                 sizeof(end_datetime_suffix) - 1);
 350                 if (ret) {
 351                         ERR("Failed to format trace chunk end date time");
 352                         goto error;
 353                 }
 354         }
 355         new_name = calloc<char>(GENERATED_CHUNK_NAME_LEN);
 356         if (!new_name) {
 357                 ERR("Failed to allocate buffer for automatically-generated trace chunk name");
 358                 goto error;
 359         }
 360         ret = snprintf(new_name, GENERATED_CHUNK_NAME_LEN, "%s%s-%" PRIu64,
 361                         start_datetime, end_datetime_suffix, chunk_id);
 362         if (ret >= GENERATED_CHUNK_NAME_LEN || ret == -1) {
 363                 ERR("Failed to format trace chunk name");
 364                 goto error;
 365         }
 366
 367         return new_name;
 368 error:
 369         free(new_name);
 370         return NULL;
 371 }
 372
 373 static
 374 void lttng_trace_chunk_init(struct lttng_trace_chunk *chunk)
 375 {
 376         urcu_ref_init(&chunk->ref);
 377         pthread_mutex_init(&chunk->lock, NULL);
 378         lttng_dynamic_pointer_array_init(&chunk->top_level_directories, free);
 379         lttng_dynamic_pointer_array_init(&chunk->files, free);
 380 }
 381
 382 static
 383 void lttng_trace_chunk_fini(struct lttng_trace_chunk *chunk)
 384 {
 385         if (chunk->session_output_directory) {
 386                 lttng_directory_handle_put(
 387                                 chunk->session_output_directory);
 388                 chunk->session_output_directory = NULL;
 389         }
 390         if (chunk->chunk_directory) {
 391                 lttng_directory_handle_put(chunk->chunk_directory);
 392                 chunk->chunk_directory = NULL;
 393         }
 394         free(chunk->name);
 395         chunk->name = NULL;
 396         free(chunk->path);
 397         chunk->path = NULL;
 398         lttng_dynamic_pointer_array_reset(&chunk->top_level_directories);
 399         lttng_dynamic_pointer_array_reset(&chunk->files);
 400         pthread_mutex_destroy(&chunk->lock);
 401 }
 402
 403 static
 404 struct lttng_trace_chunk *lttng_trace_chunk_allocate(void)
 405 {
 406         struct lttng_trace_chunk *chunk = NULL;
 407
 408         chunk = zmalloc<lttng_trace_chunk>();
 409         if (!chunk) {
 410                 ERR("Failed to allocate trace chunk");
 411                 goto end;
 412         }
 413         lttng_trace_chunk_init(chunk);
 414 end:
 415         return chunk;
 416 }
 417
 418 struct lttng_trace_chunk *lttng_trace_chunk_create_anonymous(void)
 419 {
 420         DBG("Creating anonymous trace chunk");
 421         return lttng_trace_chunk_allocate();
 422 }
 423
 424 struct lttng_trace_chunk *lttng_trace_chunk_create(
 425                 uint64_t chunk_id, time_t chunk_creation_time, const char *path)
 426 {
 427         struct lttng_trace_chunk *chunk;
 428         char chunk_creation_datetime_buf[16] = {};
 429         const char *chunk_creation_datetime_str = "(formatting error)";
 430         struct tm timeinfo_buf, *timeinfo;
 431
 432         timeinfo = localtime_r(&chunk_creation_time, &timeinfo_buf);
 433         if (timeinfo) {
 434                 size_t strftime_ret;
 435
 436                 /* Don't fail because of this; it is only used for logging. */
 437                 strftime_ret = strftime(chunk_creation_datetime_buf,
 438                                 sizeof(chunk_creation_datetime_buf),
 439                                 "%Y%m%d-%H%M%S", timeinfo);
 440                 if (strftime_ret) {
 441                         chunk_creation_datetime_str =
 442                                         chunk_creation_datetime_buf;
 443                 }
 444         }
 445
 446         DBG("Creating trace chunk: chunk_id = %" PRIu64 ", creation time = %s",
 447                         chunk_id, chunk_creation_datetime_str);
 448         chunk = lttng_trace_chunk_allocate();
 449         if (!chunk) {
 450                 goto end;
 451         }
 452
 453         LTTNG_OPTIONAL_SET(&chunk->id, chunk_id);
 454         LTTNG_OPTIONAL_SET(&chunk->timestamp_creation, chunk_creation_time);
 455         if (chunk_id != 0) {
 456                 chunk->name = generate_chunk_name(chunk_id,
 457                                 chunk_creation_time, NULL);
 458                 if (!chunk->name) {
 459                         ERR("Failed to allocate trace chunk name storage");
 460                         goto error;
 461                 }
 462         }
 463         if (path) {
 464                 chunk->path = strdup(path);
 465                 if (!chunk->path) {
 466                         goto error;
 467                 }
 468         } else {
 469                 if (chunk->name) {
 470                         chunk->path = strdup(chunk->name);
 471                         if (!chunk->path) {
 472                                 goto error;
 473                         }
 474                 }
 475         }
 476
 477         DBG("Chunk name set to \"%s\"", chunk->name ? : "(none)");
 478 end:
 479         return chunk;
 480 error:
 481         lttng_trace_chunk_put(chunk);
 482         return NULL;
 483 }
 484
 485 void lttng_trace_chunk_set_fd_tracker(struct lttng_trace_chunk *chunk,
 486                 struct fd_tracker *fd_tracker)
 487 {
 488         LTTNG_ASSERT(!chunk->session_output_directory);
 489         LTTNG_ASSERT(!chunk->chunk_directory);
 490         LTTNG_ASSERT(lttng_dynamic_pointer_array_get_count(&chunk->files) == 0);
 491         chunk->fd_tracker = fd_tracker;
 492 }
 493
 494 struct lttng_trace_chunk *lttng_trace_chunk_copy(
 495                 struct lttng_trace_chunk *source_chunk)
 496 {
 497         struct lttng_trace_chunk *new_chunk = lttng_trace_chunk_allocate();
 498
 499         if (!new_chunk) {
 500                 goto end;
 501         }
 502
 503         pthread_mutex_lock(&source_chunk->lock);
 504         /*
 505          * A new chunk is always a user; it shall create no new trace
 506          * subdirectories.
 507          */
 508         new_chunk->mode = (typeof(new_chunk->mode)) {
 509                 .is_set = true,
 510                 .value = TRACE_CHUNK_MODE_USER,
 511         };
 512         /*
 513          * top_level_directories is not copied as it is never used
 514          * by _user_ mode chunks.
 515          */
 516         /* The new chunk is not part of a registry (yet, at least). */
 517         new_chunk->in_registry_element = false;
 518         new_chunk->name_overridden = source_chunk->name_overridden;
 519         if (source_chunk->name) {
 520                 new_chunk->name = strdup(source_chunk->name);
 521                 if (!new_chunk->name) {
 522                         ERR("Failed to copy source trace chunk name in %s()",
 523                                         __FUNCTION__);
 524                         goto error_unlock;
 525                 }
 526         }
 527         if (source_chunk->path) {
 528                 new_chunk->path = strdup(source_chunk->path);
 529                 if (!new_chunk->path) {
 530                         ERR("Failed to copy source trace chunk path in %s()",
 531                                         __FUNCTION__);
 532                 }
 533         }
 534         new_chunk->id = source_chunk->id;
 535         new_chunk->timestamp_creation = source_chunk->timestamp_creation;
 536         new_chunk->timestamp_close = source_chunk->timestamp_close;
 537         new_chunk->credentials = source_chunk->credentials;
 538         if (source_chunk->session_output_directory) {
 539                 const bool reference_acquired = lttng_directory_handle_get(
 540                                 source_chunk->session_output_directory);
 541
 542                 LTTNG_ASSERT(reference_acquired);
 543                 new_chunk->session_output_directory =
 544                                 source_chunk->session_output_directory;
 545         }
 546         if (source_chunk->chunk_directory) {
 547                 const bool reference_acquired = lttng_directory_handle_get(
 548                                 source_chunk->chunk_directory);
 549
 550                 LTTNG_ASSERT(reference_acquired);
 551                 new_chunk->chunk_directory = source_chunk->chunk_directory;
 552         }
 553         new_chunk->close_command = source_chunk->close_command;
 554         new_chunk->fd_tracker = source_chunk->fd_tracker;
 555         pthread_mutex_unlock(&source_chunk->lock);
 556 end:
 557         return new_chunk;
 558 error_unlock:
 559         pthread_mutex_unlock(&source_chunk->lock);
 560         lttng_trace_chunk_put(new_chunk);
 561         return NULL;
 562 }
 563
 564 enum lttng_trace_chunk_status lttng_trace_chunk_get_id(
 565                 struct lttng_trace_chunk *chunk, uint64_t *id)
 566 {
 567         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
 568
 569         pthread_mutex_lock(&chunk->lock);
 570         if (chunk->id.is_set) {
 571                 *id = chunk->id.value;
 572         } else {
 573                 status = LTTNG_TRACE_CHUNK_STATUS_NONE;
 574         }
 575         pthread_mutex_unlock(&chunk->lock);
 576         return status;
 577 }
 578
 579 enum lttng_trace_chunk_status lttng_trace_chunk_get_creation_timestamp(
 580                 struct lttng_trace_chunk *chunk, time_t *creation_ts)
 581
 582 {
 583         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
 584
 585         pthread_mutex_lock(&chunk->lock);
 586         if (chunk->timestamp_creation.is_set) {
 587                 *creation_ts = chunk->timestamp_creation.value;
 588         } else {
 589                 status = LTTNG_TRACE_CHUNK_STATUS_NONE;
 590         }
 591         pthread_mutex_unlock(&chunk->lock);
 592         return status;
 593 }
 594
 595 enum lttng_trace_chunk_status lttng_trace_chunk_get_close_timestamp(
 596                 struct lttng_trace_chunk *chunk, time_t *close_ts)
 597 {
 598         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
 599
 600         pthread_mutex_lock(&chunk->lock);
 601         if (chunk->timestamp_close.is_set) {
 602                 *close_ts = chunk->timestamp_close.value;
 603         } else {
 604                 status = LTTNG_TRACE_CHUNK_STATUS_NONE;
 605         }
 606         pthread_mutex_unlock(&chunk->lock);
 607         return status;
 608 }
 609
 610 enum lttng_trace_chunk_status lttng_trace_chunk_set_close_timestamp(
 611                 struct lttng_trace_chunk *chunk, time_t close_ts)
 612 {
 613         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
 614
 615         pthread_mutex_lock(&chunk->lock);
 616         if (!chunk->timestamp_creation.is_set) {
 617                 ERR("Failed to set trace chunk close timestamp: creation timestamp is unset");
 618                 status = LTTNG_TRACE_CHUNK_STATUS_INVALID_OPERATION;
 619                 goto end;
 620         }
 621
 622         /*
 623          * Note: we do not enforce that the closing timestamp be greater or
 624          * equal to the begin timestamp. These timestamps are used for
 625          * generating the chunk name and should only be used in context where
 626          * the monotonicity of time is not important. The source of those
 627          * timestamps is NOT monotonic and represent the system calendar time,
 628          * also know as the wall time.
 629          */
 630         if (chunk->timestamp_creation.value > close_ts) {
 631                 WARN("Set trace chunk close timestamp: close timestamp is before creation timestamp, begin : %ld, close : %ld",
 632                                 chunk->timestamp_creation.value, close_ts);
 633         }
 634
 635         LTTNG_OPTIONAL_SET(&chunk->timestamp_close, close_ts);
 636         if (!chunk->name_overridden) {
 637                 free(chunk->name);
 638                 chunk->name = generate_chunk_name(LTTNG_OPTIONAL_GET(chunk->id),
 639                                 LTTNG_OPTIONAL_GET(chunk->timestamp_creation),
 640                                 &close_ts);
 641                 if (!chunk->name) {
 642                         status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 643                 }
 644         }
 645 end:
 646         pthread_mutex_unlock(&chunk->lock);
 647         return status;
 648 }
 649
 650 enum lttng_trace_chunk_status lttng_trace_chunk_get_name(
 651                 struct lttng_trace_chunk *chunk, const char **name,
 652                 bool *name_overridden)
 653 {
 654         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
 655
 656         pthread_mutex_lock(&chunk->lock);
 657         if (name_overridden) {
 658                 *name_overridden = chunk->name_overridden;
 659         }
 660         if (!chunk->name) {
 661                 status = LTTNG_TRACE_CHUNK_STATUS_NONE;
 662                 goto end;
 663         }
 664         *name = chunk->name;
 665 end:
 666         pthread_mutex_unlock(&chunk->lock);
 667         return status;
 668 }
 669
 670 bool lttng_trace_chunk_get_name_overridden(struct lttng_trace_chunk *chunk)
 671 {
 672         bool name_overridden;
 673
 674         pthread_mutex_lock(&chunk->lock);
 675         name_overridden = chunk->name_overridden;
 676         pthread_mutex_unlock(&chunk->lock);
 677         return name_overridden;
 678 }
 679
 680 static
 681 bool is_valid_chunk_name(const char *name)
 682 {
 683         size_t len;
 684
 685         if (!name) {
 686                 return false;
 687         }
 688
 689         len = lttng_strnlen(name, LTTNG_NAME_MAX);
 690         if (len == 0 || len == LTTNG_NAME_MAX) {
 691                 return false;
 692         }
 693
 694         if (strchr(name, '/') || strchr(name, '.')) {
 695                 return false;
 696         }
 697
 698         return true;
 699 }
 700
 701 enum lttng_trace_chunk_status lttng_trace_chunk_override_name(
 702                 struct lttng_trace_chunk *chunk, const char *name)
 703
 704 {
 705         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
 706         char *new_name, *new_path;
 707
 708         DBG("Override trace chunk name from %s to %s", chunk->name, name);
 709         if (!is_valid_chunk_name(name)) {
 710                 ERR("Attempted to set an invalid name on a trace chunk: name = %s",
 711                                 name ? : "NULL");
 712                 status = LTTNG_TRACE_CHUNK_STATUS_INVALID_ARGUMENT;
 713                 goto end;
 714         }
 715
 716         pthread_mutex_lock(&chunk->lock);
 717         if (!chunk->id.is_set) {
 718                 ERR("Attempted to set an override name on an anonymous trace chunk: name = %s",
 719                                 name);
 720                 status = LTTNG_TRACE_CHUNK_STATUS_INVALID_OPERATION;
 721                 goto end_unlock;
 722         }
 723
 724         new_name = strdup(name);
 725         if (!new_name) {
 726                 ERR("Failed to allocate new trace chunk name");
 727                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 728                 goto end_unlock;
 729         }
 730         free(chunk->name);
 731         chunk->name = new_name;
 732
 733         new_path = strdup(name);
 734         if (!new_path) {
 735                 ERR("Failed to allocate new trace chunk path");
 736                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 737                 goto end_unlock;
 738         }
 739         free(chunk->path);
 740         chunk->path = new_path;
 741
 742         chunk->name_overridden = true;
 743 end_unlock:
 744         pthread_mutex_unlock(&chunk->lock);
 745 end:
 746         return status;
 747 }
 748
 749 static
 750 enum lttng_trace_chunk_status lttng_trace_chunk_rename_path_no_lock(
 751                 struct lttng_trace_chunk *chunk, const char *path)
 752
 753 {
 754         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
 755         struct lttng_directory_handle *rename_directory = NULL;
 756         char *new_path, *old_path;
 757         int ret;
 758
 759         if (chunk->name_overridden) {
 760                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 761                 goto end;
 762         }
 763
 764         old_path = chunk->path;
 765         DBG("lttng_trace_chunk_rename_path from %s to %s", old_path, path);
 766
 767         if ((!old_path && !path) ||
 768                         (old_path && path && !strcmp(old_path, path)))  {
 769                 goto end;
 770         }
 771         /*
 772          * Use chunk name as path if NULL path is specified.
 773          */
 774         if (!path) {
 775                 path = chunk->name;
 776         }
 777
 778         /* Renaming from "" to "" is not accepted. */
 779         if (path[0] == '\0' && old_path[0] == '\0') {
 780                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 781                 goto end;
 782         }
 783
 784         /*
 785          * If a rename is performed on a chunk for which the chunk_directory
 786          * is not set (yet), or the session_output_directory is not set
 787          * (interacting with a relay daemon), there is no rename to perform.
 788          */
 789         if (!chunk->chunk_directory ||
 790                         !chunk->session_output_directory) {
 791                 goto skip_move;
 792         }
 793
 794         if (old_path && old_path[0] != '\0' && path[0] != '\0') {
 795                 /* Rename chunk directory. */
 796                 ret = lttng_directory_handle_rename_as_user(
 797                         chunk->session_output_directory,
 798                         old_path,
 799                         chunk->session_output_directory,
 800                         path,
 801                         LTTNG_OPTIONAL_GET(chunk->credentials).use_current_user ?
 802                                 NULL :
 803                                 &chunk->credentials.value.user);
 804                 if (ret) {
 805                         PERROR("Failed to move trace chunk directory \"%s\" to \"%s\"",
 806                                         old_path, path);
 807                         status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 808                         goto end;
 809                 }
 810                 rename_directory = chunk->fd_tracker ?
 811                                 fd_tracker_create_directory_handle_from_handle(
 812                                                 chunk->fd_tracker,
 813                                                 chunk->session_output_directory,
 814                                                 path) :
 815                                 lttng_directory_handle_create_from_handle(
 816                                                 path,
 817                                                 chunk->session_output_directory);
 818                 if (!rename_directory) {
 819                         ERR("Failed to get handle to trace chunk rename directory");
 820                         status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 821                         goto end;
 822                 }
 823
 824                 /* Release old handle. */
 825                 lttng_directory_handle_put(chunk->chunk_directory);
 826                 /*
 827                  * Transfer new handle reference to chunk as the current chunk
 828                  * handle.
 829                  */
 830                 chunk->chunk_directory = rename_directory;
 831                 rename_directory = NULL;
 832         } else if (old_path && old_path[0] == '\0') {
 833                 size_t i, count = lttng_dynamic_pointer_array_get_count(
 834                                 &chunk->top_level_directories);
 835
 836                 ret = lttng_directory_handle_create_subdirectory_as_user(
 837                                 chunk->session_output_directory,
 838                                 path,
 839                                 DIR_CREATION_MODE,
 840                                 LTTNG_OPTIONAL_GET(chunk->credentials).use_current_user ?
 841                                         NULL :
 842                                         &chunk->credentials.value.user);
 843                 if (ret) {
 844                         PERROR("Failed to create trace chunk rename directory \"%s\"",
 845                                         path);
 846                         status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 847                         goto end;
 848                 }
 849
 850                 rename_directory = lttng_directory_handle_create_from_handle(
 851                                 path, chunk->session_output_directory);
 852                 if (!rename_directory) {
 853                         ERR("Failed to get handle to trace chunk rename directory");
 854                         status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 855                         goto end;
 856                 }
 857
 858                 /* Move toplevel directories. */
 859                 for (i = 0; i < count; i++) {
 860                         const char *top_level_name =
 861                                 (const char *) lttng_dynamic_pointer_array_get_pointer(
 862                                         &chunk->top_level_directories, i);
 863
 864                         ret = lttng_directory_handle_rename_as_user(
 865                                         chunk->chunk_directory,
 866                                         top_level_name,
 867                                         rename_directory,
 868                                         top_level_name,
 869                                         LTTNG_OPTIONAL_GET(chunk->credentials).use_current_user ?
 870                                                 NULL :
 871                                                 &chunk->credentials.value.user);
 872                         if (ret) {
 873                                 PERROR("Failed to move \"%s\" to trace chunk rename directory",
 874                                                 top_level_name);
 875                                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 876                                 goto end;
 877                         }
 878                 }
 879                 /* Release old handle. */
 880                 lttng_directory_handle_put(chunk->chunk_directory);
 881                 /*
 882                  * Transfer new handle reference to chunk as the current chunk
 883                  * handle.
 884                  */
 885                 chunk->chunk_directory = rename_directory;
 886                 rename_directory = NULL;
 887         } else if (old_path) {
 888                 size_t i, count = lttng_dynamic_pointer_array_get_count(
 889                                 &chunk->top_level_directories);
 890                 const bool reference_acquired = lttng_directory_handle_get(
 891                                 chunk->session_output_directory);
 892
 893                 LTTNG_ASSERT(reference_acquired);
 894                 rename_directory = chunk->session_output_directory;
 895
 896                 /* Move toplevel directories. */
 897                 for (i = 0; i < count; i++) {
 898                         const char *top_level_name =
 899                                 (const char *) lttng_dynamic_pointer_array_get_pointer(
 900                                         &chunk->top_level_directories, i);
 901
 902                         ret = lttng_directory_handle_rename_as_user(
 903                                         chunk->chunk_directory,
 904                                         top_level_name,
 905                                         rename_directory,
 906                                         top_level_name,
 907                                         LTTNG_OPTIONAL_GET(chunk->credentials).use_current_user ?
 908                                                 NULL :
 909                                                 &chunk->credentials.value.user);
 910                         if (ret) {
 911                                 PERROR("Failed to move \"%s\" to trace chunk rename directory",
 912                                                 top_level_name);
 913                                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 914                                 goto end;
 915                         }
 916                 }
 917                 /* Release old handle. */
 918                 lttng_directory_handle_put(chunk->chunk_directory);
 919                 /*
 920                  * Transfer new handle reference to chunk as the current chunk
 921                  * handle.
 922                  */
 923                 chunk->chunk_directory = rename_directory;
 924                 rename_directory = NULL;
 925
 926                 /* Remove old directory. */
 927                 status = (lttng_trace_chunk_status) lttng_directory_handle_remove_subdirectory(
 928                                 chunk->session_output_directory,
 929                                 old_path);
 930                 if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 931                         ERR("Error removing subdirectory '%s' file when deleting chunk",
 932                                 old_path);
 933                         goto end;
 934                 }
 935         } else {
 936                 /* Unexpected !old_path && !path. */
 937                 status = LTTNG_TRACE_CHUNK_STATUS_INVALID_ARGUMENT;
 938                 goto end;
 939         }
 940
 941 skip_move:
 942         new_path = strdup(path);
 943         if (!new_path) {
 944                 ERR("Failed to allocate new trace chunk path");
 945                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 946                 goto end;
 947         }
 948         free(chunk->path);
 949         chunk->path = new_path;
 950 end:
 951         lttng_directory_handle_put(rename_directory);
 952         return status;
 953 }
 954
 955 enum lttng_trace_chunk_status lttng_trace_chunk_rename_path(
 956                 struct lttng_trace_chunk *chunk, const char *path)
 957
 958 {
 959         enum lttng_trace_chunk_status status;
 960
 961         pthread_mutex_lock(&chunk->lock);
 962         status = lttng_trace_chunk_rename_path_no_lock(chunk, path);
 963         pthread_mutex_unlock(&chunk->lock);
 964
 965         return status;
 966 }
 967
 968 enum lttng_trace_chunk_status lttng_trace_chunk_get_credentials(
 969                 struct lttng_trace_chunk *chunk,
 970                 struct lttng_credentials *credentials)
 971 {
 972         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
 973
 974         pthread_mutex_lock(&chunk->lock);
 975         if (chunk->credentials.is_set) {
 976                 if (chunk->credentials.value.use_current_user) {
 977                         LTTNG_OPTIONAL_SET(&credentials->uid, geteuid());
 978                         LTTNG_OPTIONAL_SET(&credentials->gid, getegid());
 979                 } else {
 980                         *credentials = chunk->credentials.value.user;
 981                 }
 982         } else {
 983                 status = LTTNG_TRACE_CHUNK_STATUS_NONE;
 984         }
 985         pthread_mutex_unlock(&chunk->lock);
 986         return status;
 987 }
 988
 989 enum lttng_trace_chunk_status lttng_trace_chunk_set_credentials(
 990                 struct lttng_trace_chunk *chunk,
 991                 const struct lttng_credentials *user_credentials)
 992 {
 993         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
 994         const struct chunk_credentials credentials = {
 995                 .use_current_user = false,
 996                 .user = *user_credentials,
 997         };
 998
 999         pthread_mutex_lock(&chunk->lock);
1000         if (chunk->credentials.is_set) {
1001                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1002                 goto end;
1003         }
1004         LTTNG_OPTIONAL_SET(&chunk->credentials, credentials);
1005 end:
1006         pthread_mutex_unlock(&chunk->lock);
1007         return status;
1008 }
1009
1010 enum lttng_trace_chunk_status lttng_trace_chunk_set_credentials_current_user(
1011                 struct lttng_trace_chunk *chunk)
1012 {
1013         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1014         const struct chunk_credentials credentials = {
1015                 .use_current_user = true,
1016                 .user = {},
1017         };
1018
1019         pthread_mutex_lock(&chunk->lock);
1020         if (chunk->credentials.is_set) {
1021                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1022                 goto end;
1023         }
1024         LTTNG_OPTIONAL_SET(&chunk->credentials, credentials);
1025 end:
1026         pthread_mutex_unlock(&chunk->lock);
1027         return status;
1028 }
1029
1030
1031 enum lttng_trace_chunk_status lttng_trace_chunk_set_as_owner(
1032                 struct lttng_trace_chunk *chunk,
1033                 struct lttng_directory_handle *session_output_directory)
1034 {
1035         int ret;
1036         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1037         struct lttng_directory_handle *chunk_directory_handle = NULL;
1038         bool reference_acquired;
1039
1040         pthread_mutex_lock(&chunk->lock);
1041         if (chunk->mode.is_set) {
1042                 status = LTTNG_TRACE_CHUNK_STATUS_INVALID_OPERATION;
1043                 goto end;
1044         }
1045         if (!chunk->credentials.is_set) {
1046                 /*
1047                  * Fatal error, credentials must be set before a
1048                  * directory is created.
1049                  */
1050                 ERR("Credentials of trace chunk are unset: refusing to set session output directory");
1051                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1052                 goto end;
1053         }
1054         if (chunk->path && chunk->path[0] != '\0') {
1055                 ret = lttng_directory_handle_create_subdirectory_as_user(
1056                                 session_output_directory,
1057                                 chunk->path,
1058                                 DIR_CREATION_MODE,
1059                                 !chunk->credentials.value.use_current_user ?
1060                                         &chunk->credentials.value.user : NULL);
1061                 if (ret) {
1062                         PERROR("Failed to create chunk output directory \"%s\"",
1063                                 chunk->path);
1064                         status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1065                         goto end;
1066                 }
1067                 chunk_directory_handle =
1068                                 chunk->fd_tracker ?
1069                                         fd_tracker_create_directory_handle_from_handle(
1070                                                         chunk->fd_tracker,
1071                                                         session_output_directory,
1072                                                         chunk->path) :
1073                                         lttng_directory_handle_create_from_handle(
1074                                                         chunk->path,
1075                                                         session_output_directory);
1076                 if (!chunk_directory_handle) {
1077                         /* The function already logs on all error paths. */
1078                         status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1079                         goto end;
1080                 }
1081         } else {
1082                 /*
1083                  * A nameless chunk does not need its own output directory.
1084                  * The session's output directory will be used.
1085                  */
1086                 reference_acquired = lttng_directory_handle_get(
1087                                 session_output_directory);
1088
1089                 LTTNG_ASSERT(reference_acquired);
1090                 chunk_directory_handle = session_output_directory;
1091         }
1092         chunk->chunk_directory = chunk_directory_handle;
1093         chunk_directory_handle = NULL;
1094         reference_acquired = lttng_directory_handle_get(
1095                         session_output_directory);
1096         LTTNG_ASSERT(reference_acquired);
1097         chunk->session_output_directory = session_output_directory;
1098         LTTNG_OPTIONAL_SET(&chunk->mode, TRACE_CHUNK_MODE_OWNER);
1099 end:
1100         pthread_mutex_unlock(&chunk->lock);
1101         return status;
1102 }
1103
1104 enum lttng_trace_chunk_status lttng_trace_chunk_set_as_user(
1105                 struct lttng_trace_chunk *chunk,
1106                 struct lttng_directory_handle *chunk_directory)
1107 {
1108         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1109         bool reference_acquired;
1110
1111         pthread_mutex_lock(&chunk->lock);
1112         if (chunk->mode.is_set) {
1113                 status = LTTNG_TRACE_CHUNK_STATUS_INVALID_OPERATION;
1114                 goto end;
1115         }
1116         if (!chunk->credentials.is_set) {
1117                 ERR("Credentials of trace chunk are unset: refusing to set chunk output directory");
1118                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1119                 goto end;
1120         }
1121         reference_acquired = lttng_directory_handle_get(chunk_directory);
1122         LTTNG_ASSERT(reference_acquired);
1123         chunk->chunk_directory = chunk_directory;
1124         LTTNG_OPTIONAL_SET(&chunk->mode, TRACE_CHUNK_MODE_USER);
1125 end:
1126         pthread_mutex_unlock(&chunk->lock);
1127         return status;
1128 }
1129
1130 enum lttng_trace_chunk_status
1131 lttng_trace_chunk_get_session_output_directory_handle(
1132                 struct lttng_trace_chunk *chunk,
1133                 struct lttng_directory_handle **handle)
1134 {
1135         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1136
1137         pthread_mutex_lock(&chunk->lock);
1138         if (!chunk->session_output_directory) {
1139                 status = LTTNG_TRACE_CHUNK_STATUS_NONE;
1140                 *handle = NULL;
1141                 goto end;
1142         } else {
1143                 const bool reference_acquired = lttng_directory_handle_get(
1144                                 chunk->session_output_directory);
1145
1146                 LTTNG_ASSERT(reference_acquired);
1147                 *handle = chunk->session_output_directory;
1148         }
1149 end:
1150         pthread_mutex_unlock(&chunk->lock);
1151         return status;
1152 }
1153
1154 enum lttng_trace_chunk_status lttng_trace_chunk_borrow_chunk_directory_handle(
1155                 struct lttng_trace_chunk *chunk,
1156                 const struct lttng_directory_handle **handle)
1157 {
1158         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1159
1160         pthread_mutex_lock(&chunk->lock);
1161         if (!chunk->chunk_directory) {
1162                 status = LTTNG_TRACE_CHUNK_STATUS_NONE;
1163                 goto end;
1164         }
1165
1166         *handle = chunk->chunk_directory;
1167 end:
1168         pthread_mutex_unlock(&chunk->lock);
1169         return status;
1170 }
1171
1172 /* Add a top-level directory to the trace chunk if it was previously unknown. */
1173 static
1174 int add_top_level_directory_unique(struct lttng_trace_chunk *chunk,
1175                 const char *new_path)
1176 {
1177         int ret = 0;
1178         bool found = false;
1179         size_t i, count = lttng_dynamic_pointer_array_get_count(
1180                         &chunk->top_level_directories);
1181         const char *new_path_separator_pos = strchr(new_path, '/');
1182         const ptrdiff_t new_path_top_level_len = new_path_separator_pos ?
1183                         new_path_separator_pos - new_path : strlen(new_path);
1184
1185         for (i = 0; i < count; i++) {
1186                 const char *path = (const char *) lttng_dynamic_pointer_array_get_pointer(
1187                                 &chunk->top_level_directories, i);
1188                 const ptrdiff_t path_top_level_len = strlen(path);
1189
1190                 if (path_top_level_len != new_path_top_level_len) {
1191                         continue;
1192                 }
1193                 if (!strncmp(path, new_path, path_top_level_len)) {
1194                         found = true;
1195                         break;
1196                 }
1197         }
1198
1199         if (!found) {
1200                 char *copy = lttng_strndup(new_path, new_path_top_level_len);
1201
1202                 DBG("Adding new top-level directory \"%s\" to trace chunk \"%s\"",
1203                                 new_path, chunk->name ? : "(unnamed)");
1204                 if (!copy) {
1205                         PERROR("Failed to copy path");
1206                         ret = -1;
1207                         goto end;
1208                 }
1209                 ret = lttng_dynamic_pointer_array_add_pointer(
1210                                 &chunk->top_level_directories, copy);
1211                 if (ret) {
1212                         ERR("Allocation failure while adding top-level directory entry to a trace chunk");
1213                         free(copy);
1214                         goto end;
1215                 }
1216         }
1217 end:
1218         return ret;
1219 }
1220
1221 enum lttng_trace_chunk_status lttng_trace_chunk_create_subdirectory(
1222                 struct lttng_trace_chunk *chunk,
1223                 const char *path)
1224 {
1225         int ret;
1226         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1227
1228         DBG("Creating trace chunk subdirectory \"%s\"", path);
1229         pthread_mutex_lock(&chunk->lock);
1230         if (!chunk->credentials.is_set) {
1231                 /*
1232                  * Fatal error, credentials must be set before a
1233                  * directory is created.
1234                  */
1235                 ERR("Credentials of trace chunk are unset: refusing to create subdirectory \"%s\"",
1236                                 path);
1237                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1238                 goto end;
1239         }
1240         if (!chunk->mode.is_set ||
1241                         chunk->mode.value != TRACE_CHUNK_MODE_OWNER) {
1242                 ERR("Attempted to create trace chunk subdirectory \"%s\" through a non-owner chunk",
1243                                 path);
1244                 status = LTTNG_TRACE_CHUNK_STATUS_INVALID_OPERATION;
1245                 goto end;
1246         }
1247         if (!chunk->chunk_directory) {
1248                 ERR("Attempted to create trace chunk subdirectory \"%s\" before setting the chunk output directory",
1249                                 path);
1250                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1251                 goto end;
1252         }
1253         if (*path == '/') {
1254                 ERR("Refusing to create absolute trace chunk directory \"%s\"",
1255                                 path);
1256                 status = LTTNG_TRACE_CHUNK_STATUS_INVALID_ARGUMENT;
1257                 goto end;
1258         }
1259         ret = lttng_directory_handle_create_subdirectory_recursive_as_user(
1260                         chunk->chunk_directory, path,
1261                         DIR_CREATION_MODE,
1262                         chunk->credentials.value.use_current_user ?
1263                                         NULL : &chunk->credentials.value.user);
1264         if (ret) {
1265                 PERROR("Failed to create trace chunk subdirectory \"%s\"",
1266                                 path);
1267                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1268                 goto end;
1269         }
1270         ret = add_top_level_directory_unique(chunk, path);
1271         if (ret) {
1272                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1273                 goto end;
1274         }
1275 end:
1276         pthread_mutex_unlock(&chunk->lock);
1277         return status;
1278 }
1279
1280 /*
1281  * TODO: Implement O(1) lookup.
1282  */
1283 static
1284 bool lttng_trace_chunk_find_file(struct lttng_trace_chunk *chunk,
1285                 const char *path, size_t *index)
1286 {
1287         size_t i, count;
1288
1289         count = lttng_dynamic_pointer_array_get_count(&chunk->files);
1290         for (i = 0; i < count; i++) {
1291                 const char *iter_path =
1292                         (const char *) lttng_dynamic_pointer_array_get_pointer(
1293                                 &chunk->files, i);
1294                 if (!strcmp(iter_path, path)) {
1295                         if (index) {
1296                                 *index = i;
1297                         }
1298                         return true;
1299                 }
1300         }
1301         return false;
1302 }
1303
1304 static
1305 enum lttng_trace_chunk_status lttng_trace_chunk_add_file(
1306                 struct lttng_trace_chunk *chunk,
1307                 const char *path)
1308 {
1309         char *copy;
1310         int ret;
1311         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1312
1313         if (lttng_trace_chunk_find_file(chunk, path, NULL)) {
1314                 return LTTNG_TRACE_CHUNK_STATUS_OK;
1315         }
1316         DBG("Adding new file \"%s\" to trace chunk \"%s\"",
1317                         path, chunk->name ? : "(unnamed)");
1318         copy = strdup(path);
1319         if (!copy) {
1320                 PERROR("Failed to copy path");
1321                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1322                 goto end;
1323         }
1324         ret = lttng_dynamic_pointer_array_add_pointer(
1325                         &chunk->files, copy);
1326         if (ret) {
1327                 ERR("Allocation failure while adding file to a trace chunk");
1328                 free(copy);
1329                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1330                 goto end;
1331         }
1332 end:
1333         return status;
1334 }
1335
1336 static
1337 void lttng_trace_chunk_remove_file(
1338                 struct lttng_trace_chunk *chunk,
1339                 const char *path)
1340 {
1341         size_t index;
1342         bool found;
1343         int ret;
1344
1345         found = lttng_trace_chunk_find_file(chunk, path, &index);
1346         if (!found) {
1347                 return;
1348         }
1349         ret = lttng_dynamic_pointer_array_remove_pointer(
1350                         &chunk->files, index);
1351         LTTNG_ASSERT(!ret);
1352 }
1353
1354 static
1355 enum lttng_trace_chunk_status _lttng_trace_chunk_open_fs_handle_locked(
1356                 struct lttng_trace_chunk *chunk,
1357                 const char *file_path,
1358                 int flags,
1359                 mode_t mode,
1360                 struct fs_handle **out_handle,
1361                 bool expect_no_file)
1362 {
1363         int ret;
1364         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1365
1366         DBG("Opening trace chunk file \"%s\"", file_path);
1367         if (!chunk->credentials.is_set) {
1368                 /*
1369                  * Fatal error, credentials must be set before a
1370                  * file is created.
1371                  */
1372                 ERR("Credentials of trace chunk are unset: refusing to open file \"%s\"",
1373                                 file_path);
1374                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1375                 goto end;
1376         }
1377         if (!chunk->chunk_directory) {
1378                 ERR("Attempted to open trace chunk file \"%s\" before setting the chunk output directory",
1379                                 file_path);
1380                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1381                 goto end;
1382         }
1383         status = lttng_trace_chunk_add_file(chunk, file_path);
1384         if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
1385                 goto end;
1386         }
1387         if (chunk->fd_tracker) {
1388                 LTTNG_ASSERT(chunk->credentials.value.use_current_user);
1389                 *out_handle = fd_tracker_open_fs_handle(chunk->fd_tracker,
1390                                 chunk->chunk_directory, file_path, flags, &mode);
1391                 ret = *out_handle ? 0 : -1;
1392         } else {
1393                 ret = lttng_directory_handle_open_file_as_user(
1394                                 chunk->chunk_directory, file_path, flags, mode,
1395                                 chunk->credentials.value.use_current_user ?
1396                                                 NULL :
1397                                                 &chunk->credentials.value.user);
1398                 if (ret >= 0) {
1399                         *out_handle = fs_handle_untracked_create(
1400                                         chunk->chunk_directory, file_path, ret);
1401                         if (!*out_handle) {
1402                                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1403                                 goto end;
1404                         }
1405                 }
1406         }
1407         if (ret < 0) {
1408                 if (errno == ENOENT && expect_no_file) {
1409                         status = LTTNG_TRACE_CHUNK_STATUS_NO_FILE;
1410                 } else {
1411                         PERROR("Failed to open file relative to trace chunk file_path = \"%s\", flags = %d, mode = %d",
1412                                 file_path, flags, (int) mode);
1413                         status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1414                 }
1415                 lttng_trace_chunk_remove_file(chunk, file_path);
1416                 goto end;
1417         }
1418 end:
1419         return status;
1420 }
1421
1422 enum lttng_trace_chunk_status lttng_trace_chunk_open_fs_handle(
1423                 struct lttng_trace_chunk *chunk,
1424                 const char *file_path,
1425                 int flags,
1426                 mode_t mode,
1427                 struct fs_handle **out_handle,
1428                 bool expect_no_file)
1429 {
1430         enum lttng_trace_chunk_status status;
1431
1432         pthread_mutex_lock(&chunk->lock);
1433         status = _lttng_trace_chunk_open_fs_handle_locked(chunk, file_path,
1434                         flags, mode, out_handle, expect_no_file);
1435         pthread_mutex_unlock(&chunk->lock);
1436         return status;
1437 }
1438
1439 enum lttng_trace_chunk_status lttng_trace_chunk_open_file(
1440                 struct lttng_trace_chunk *chunk,
1441                 const char *file_path,
1442                 int flags,
1443                 mode_t mode,
1444                 int *out_fd,
1445                 bool expect_no_file)
1446 {
1447         enum lttng_trace_chunk_status status;
1448         struct fs_handle *fs_handle;
1449
1450         pthread_mutex_lock(&chunk->lock);
1451         /*
1452          * Using this method is never valid when an fd_tracker is being
1453          * used since the resulting file descriptor would not be tracked.
1454          */
1455         LTTNG_ASSERT(!chunk->fd_tracker);
1456         status = _lttng_trace_chunk_open_fs_handle_locked(chunk, file_path,
1457                         flags, mode, &fs_handle, expect_no_file);
1458         pthread_mutex_unlock(&chunk->lock);
1459
1460         if (status == LTTNG_TRACE_CHUNK_STATUS_OK) {
1461                 *out_fd = fs_handle_get_fd(fs_handle);
1462                 /*
1463                  * Does not close the fd; we just "unbox" it from the fs_handle.
1464                  */
1465                 fs_handle_untracked_destroy(container_of(
1466                                 fs_handle, struct fs_handle_untracked, parent));
1467         }
1468
1469         return status;
1470 }
1471
1472 int lttng_trace_chunk_unlink_file(struct lttng_trace_chunk *chunk,
1473                 const char *file_path)
1474 {
1475         int ret;
1476         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1477
1478         DBG("Unlinking trace chunk file \"%s\"", file_path);
1479         pthread_mutex_lock(&chunk->lock);
1480         if (!chunk->credentials.is_set) {
1481                 /*
1482                  * Fatal error, credentials must be set before a
1483                  * file is unlinked.
1484                  */
1485                 ERR("Credentials of trace chunk are unset: refusing to unlink file \"%s\"",
1486                                 file_path);
1487                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1488                 goto end;
1489         }
1490         if (!chunk->chunk_directory) {
1491                 ERR("Attempted to unlink trace chunk file \"%s\" before setting the chunk output directory",
1492                                 file_path);
1493                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1494                 goto end;
1495         }
1496         ret = lttng_directory_handle_unlink_file_as_user(
1497                         chunk->chunk_directory, file_path,
1498                         chunk->credentials.value.use_current_user ?
1499                                         NULL : &chunk->credentials.value.user);
1500         if (ret < 0) {
1501                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1502                 goto end;
1503         }
1504         lttng_trace_chunk_remove_file(chunk, file_path);
1505 end:
1506         pthread_mutex_unlock(&chunk->lock);
1507         return status;
1508 }
1509
1510 static
1511 int lttng_trace_chunk_remove_subdirectory_recursive(struct lttng_trace_chunk *chunk,
1512                 const char *path)
1513 {
1514         int ret;
1515         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1516
1517         DBG("Recursively removing trace chunk directory \"%s\"", path);
1518         pthread_mutex_lock(&chunk->lock);
1519         if (!chunk->credentials.is_set) {
1520                 /*
1521                  * Fatal error, credentials must be set before a
1522                  * directory is removed.
1523                  */
1524                 ERR("Credentials of trace chunk are unset: refusing to recursively remove directory \"%s\"",
1525                                 path);
1526                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1527                 goto end;
1528         }
1529         if (!chunk->chunk_directory) {
1530                 ERR("Attempted to recursively remove trace chunk directory \"%s\" before setting the chunk output directory",
1531                                 path);
1532                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1533                 goto end;
1534         }
1535         ret = lttng_directory_handle_remove_subdirectory_recursive_as_user(
1536                         chunk->chunk_directory, path,
1537                         chunk->credentials.value.use_current_user ?
1538                                         NULL : &chunk->credentials.value.user,
1539                         LTTNG_DIRECTORY_HANDLE_SKIP_NON_EMPTY_FLAG);
1540         if (ret < 0) {
1541                 status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
1542                 goto end;
1543         }
1544 end:
1545         pthread_mutex_unlock(&chunk->lock);
1546         return status;
1547 }
1548
1549 static
1550 int lttng_trace_chunk_move_to_completed_post_release(
1551                 struct lttng_trace_chunk *trace_chunk)
1552 {
1553         int ret = 0;
1554         char *archived_chunk_name = NULL;
1555         const uint64_t chunk_id = LTTNG_OPTIONAL_GET(trace_chunk->id);
1556         const time_t creation_timestamp =
1557                         LTTNG_OPTIONAL_GET(trace_chunk->timestamp_creation);
1558         const time_t close_timestamp =
1559                         LTTNG_OPTIONAL_GET(trace_chunk->timestamp_close);
1560         struct lttng_directory_handle *archived_chunks_directory = NULL;
1561         enum lttng_trace_chunk_status status;
1562
1563         if (!trace_chunk->mode.is_set ||
1564                         trace_chunk->mode.value != TRACE_CHUNK_MODE_OWNER ||
1565                         !trace_chunk->session_output_directory) {
1566                 /*
1567                  * This command doesn't need to run if the output is remote
1568                  * or if the trace chunk is not owned by this process.
1569                  */
1570                 goto end;
1571         }
1572
1573         LTTNG_ASSERT(trace_chunk->mode.value == TRACE_CHUNK_MODE_OWNER);
1574         LTTNG_ASSERT(!trace_chunk->name_overridden);
1575         LTTNG_ASSERT(trace_chunk->path);
1576
1577         archived_chunk_name = generate_chunk_name(chunk_id, creation_timestamp,
1578                         &close_timestamp);
1579         if (!archived_chunk_name) {
1580                 ERR("Failed to generate archived trace chunk name while renaming trace chunk");
1581                 ret = -1;
1582                 goto end;
1583         }
1584
1585         ret = lttng_directory_handle_create_subdirectory_as_user(
1586                         trace_chunk->session_output_directory,
1587                         DEFAULT_ARCHIVED_TRACE_CHUNKS_DIRECTORY,
1588                         DIR_CREATION_MODE,
1589                         !trace_chunk->credentials.value.use_current_user ?
1590                                         &trace_chunk->credentials.value.user :
1591                                         NULL);
1592         if (ret) {
1593                 PERROR("Failed to create \"" DEFAULT_ARCHIVED_TRACE_CHUNKS_DIRECTORY
1594                                 "\" directory for archived trace chunks");
1595                 goto end;
1596         }
1597
1598         archived_chunks_directory = trace_chunk->fd_tracker ?
1599                         fd_tracker_create_directory_handle_from_handle(
1600                                         trace_chunk->fd_tracker,
1601                                         trace_chunk->session_output_directory,
1602                                         DEFAULT_ARCHIVED_TRACE_CHUNKS_DIRECTORY) :
1603                         lttng_directory_handle_create_from_handle(
1604                                         DEFAULT_ARCHIVED_TRACE_CHUNKS_DIRECTORY,
1605                                         trace_chunk->session_output_directory);
1606         if (!archived_chunks_directory) {
1607                 PERROR("Failed to get handle to archived trace chunks directory");
1608                 ret = -1;
1609                 goto end;
1610         }
1611
1612         /*
1613          * Make sure chunk is renamed to old directory if not already done by
1614          * the creation of the next chunk. This happens if a rotation is
1615          * performed while tracing is stopped.
1616          */
1617         if (!trace_chunk->path || strcmp(trace_chunk->path,
1618                         DEFAULT_CHUNK_TMP_OLD_DIRECTORY)) {
1619                 status = lttng_trace_chunk_rename_path_no_lock(trace_chunk,
1620                                 DEFAULT_CHUNK_TMP_OLD_DIRECTORY);
1621                 if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
1622                         ERR("Failed to rename chunk to %s", DEFAULT_CHUNK_TMP_OLD_DIRECTORY);
1623                         ret = -1;
1624                         goto end;
1625                 }
1626         }
1627
1628         ret = lttng_directory_handle_rename_as_user(
1629                         trace_chunk->session_output_directory,
1630                         trace_chunk->path,
1631                         archived_chunks_directory,
1632                         archived_chunk_name,
1633                         LTTNG_OPTIONAL_GET(trace_chunk->credentials).use_current_user ?
1634                                 NULL :
1635                                 &trace_chunk->credentials.value.user);
1636         if (ret) {
1637                 PERROR("Failed to rename folder \"%s\" to \"%s\"",
1638                                 trace_chunk->path,
1639                                 archived_chunk_name);
1640         }
1641
1642 end:
1643         lttng_directory_handle_put(archived_chunks_directory);
1644         free(archived_chunk_name);
1645         return ret;
1646 }
1647
1648 static
1649 int lttng_trace_chunk_no_operation(struct lttng_trace_chunk *trace_chunk __attribute__((unused)))
1650 {
1651         return 0;
1652 }
1653
1654 static
1655 int lttng_trace_chunk_delete_post_release_user(
1656                 struct lttng_trace_chunk *trace_chunk)
1657 {
1658         int ret = 0;
1659
1660         DBG("Trace chunk \"delete\" close command post-release (User)");
1661
1662         /* Unlink all files. */
1663         while (lttng_dynamic_pointer_array_get_count(&trace_chunk->files) != 0) {
1664                 enum lttng_trace_chunk_status status;
1665                 const char *path;
1666
1667                 /* Remove first. */
1668                 path = (const char *) lttng_dynamic_pointer_array_get_pointer(
1669                         &trace_chunk->files, 0);
1670                 DBG("Unlink file: %s", path);
1671                 status = (lttng_trace_chunk_status) lttng_trace_chunk_unlink_file(trace_chunk, path);
1672                 if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
1673                         ERR("Error unlinking file '%s' when deleting chunk", path);
1674                         ret = -1;
1675                         goto end;
1676                 }
1677         }
1678 end:
1679         return ret;
1680 }
1681
1682 static
1683 int lttng_trace_chunk_delete_post_release_owner(
1684                 struct lttng_trace_chunk *trace_chunk)
1685 {
1686         enum lttng_trace_chunk_status status;
1687         size_t i, count;
1688         int ret = 0;
1689
1690         ret = lttng_trace_chunk_delete_post_release_user(trace_chunk);
1691         if (ret) {
1692                 goto end;
1693         }
1694
1695         DBG("Trace chunk \"delete\" close command post-release (Owner)");
1696
1697         LTTNG_ASSERT(trace_chunk->session_output_directory);
1698         LTTNG_ASSERT(trace_chunk->chunk_directory);
1699
1700         /* Remove empty directories. */
1701         count = lttng_dynamic_pointer_array_get_count(
1702                         &trace_chunk->top_level_directories);
1703
1704         for (i = 0; i < count; i++) {
1705                 const char *top_level_name =
1706                         (const char *) lttng_dynamic_pointer_array_get_pointer(
1707                                 &trace_chunk->top_level_directories, i);
1708
1709                 status = (lttng_trace_chunk_status) lttng_trace_chunk_remove_subdirectory_recursive(trace_chunk, top_level_name);
1710                 if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
1711                         ERR("Error recursively removing subdirectory '%s' file when deleting chunk",
1712                                         top_level_name);
1713                         ret = -1;
1714                         break;
1715                 }
1716         }
1717         if (!ret) {
1718                 lttng_directory_handle_put(trace_chunk->chunk_directory);
1719                 trace_chunk->chunk_directory = NULL;
1720
1721                 if (trace_chunk->path && trace_chunk->path[0] != '\0') {
1722                         status = (lttng_trace_chunk_status) lttng_directory_handle_remove_subdirectory(
1723                                         trace_chunk->session_output_directory,
1724                                         trace_chunk->path);
1725                         if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
1726                                 ERR("Error removing subdirectory '%s' file when deleting chunk",
1727                                         trace_chunk->path);
1728                                 ret = -1;
1729                         }
1730                 }
1731         }
1732         free(trace_chunk->path);
1733         trace_chunk->path = NULL;
1734 end:
1735         return ret;
1736 }
1737
1738 /*
1739  * For local files, session and consumer daemons all run the delete hook. The
1740  * consumer daemons have the list of files to unlink, and technically the
1741  * session daemon is the owner of the chunk. Unlink all files owned by each
1742  * consumer daemon.
1743  */
1744 static
1745 int lttng_trace_chunk_delete_post_release(
1746                 struct lttng_trace_chunk *trace_chunk)
1747 {
1748         if (!trace_chunk->chunk_directory) {
1749                 return 0;
1750         }
1751
1752         if (trace_chunk->mode.value == TRACE_CHUNK_MODE_OWNER) {
1753                 return lttng_trace_chunk_delete_post_release_owner(trace_chunk);
1754         } else {
1755                 return lttng_trace_chunk_delete_post_release_user(trace_chunk);
1756         }
1757 }
1758
1759 enum lttng_trace_chunk_status lttng_trace_chunk_get_close_command(
1760                 struct lttng_trace_chunk *chunk,
1761                 enum lttng_trace_chunk_command_type *command_type)
1762 {
1763         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1764
1765         pthread_mutex_lock(&chunk->lock);
1766         if (chunk->close_command.is_set) {
1767                 *command_type = chunk->close_command.value;
1768                 status = LTTNG_TRACE_CHUNK_STATUS_OK;
1769         } else {
1770                 status = LTTNG_TRACE_CHUNK_STATUS_NONE;
1771         }
1772         pthread_mutex_unlock(&chunk->lock);
1773         return status;
1774 }
1775
1776 enum lttng_trace_chunk_status lttng_trace_chunk_set_close_command(
1777                 struct lttng_trace_chunk *chunk,
1778                 enum lttng_trace_chunk_command_type close_command)
1779 {
1780         enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
1781
1782         if (close_command < LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED ||
1783                         close_command >= LTTNG_TRACE_CHUNK_COMMAND_TYPE_MAX) {
1784                 status = LTTNG_TRACE_CHUNK_STATUS_INVALID_ARGUMENT;
1785                 goto end;
1786         }
1787
1788         pthread_mutex_lock(&chunk->lock);
1789         if (chunk->close_command.is_set) {
1790                 DBG("Overriding trace chunk close command from \"%s\" to \"%s\"",
1791                                 lttng_trace_chunk_command_type_str(chunk->close_command.value),
1792                                 lttng_trace_chunk_command_type_str(close_command));
1793         } else {
1794                 DBG("Setting trace chunk close command to \"%s\"",
1795                                 lttng_trace_chunk_command_type_str(close_command));
1796         }
1797         /*
1798          * Unset close command for no-op for backward compatibility with relayd
1799          * 2.11.
1800          */
1801         if (close_command != LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION) {
1802                 LTTNG_OPTIONAL_SET(&chunk->close_command, close_command);
1803         } else {
1804                 LTTNG_OPTIONAL_UNSET(&chunk->close_command);
1805         }
1806         pthread_mutex_unlock(&chunk->lock);
1807 end:
1808         return status;
1809 }
1810
1811 const char *lttng_trace_chunk_command_type_get_name(
1812                 enum lttng_trace_chunk_command_type command)
1813 {
1814         switch (command) {
1815         case LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED:
1816                 return "move to completed trace chunk folder";
1817         case LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION:
1818                 return "no operation";
1819         case LTTNG_TRACE_CHUNK_COMMAND_TYPE_DELETE:
1820                 return "delete";
1821         default:
1822                 abort();
1823         }
1824 }
1825
1826 bool lttng_trace_chunk_ids_equal(const struct lttng_trace_chunk *chunk_a,
1827                 const struct lttng_trace_chunk *chunk_b)
1828 {
1829         bool equal = false;
1830
1831         if (chunk_a == chunk_b) {
1832                 equal = true;
1833                 goto end;
1834         }
1835
1836         if (!!chunk_a ^ !!chunk_b) {
1837                 goto end;
1838         }
1839
1840         if (chunk_a->id.is_set ^ chunk_a->id.is_set) {
1841                 /* One id is set and not the other, thus they are not equal. */
1842                 goto end;
1843         }
1844
1845         if (!chunk_a->id.is_set) {
1846                 /* Both ids are unset. */
1847                 equal = true;
1848         } else {
1849                 equal = chunk_a->id.value == chunk_b->id.value;
1850         }
1851
1852 end:
1853         return equal;
1854 }
1855
1856 bool lttng_trace_chunk_get(struct lttng_trace_chunk *chunk)
1857 {
1858         return urcu_ref_get_unless_zero(&chunk->ref);
1859 }
1860
1861 static
1862 void free_lttng_trace_chunk_registry_element(struct rcu_head *node)
1863 {
1864         struct lttng_trace_chunk_registry_element *element =
1865                         container_of(node, typeof(*element), rcu_node);
1866
1867         free(element);
1868 }
1869
1870 static
1871 void lttng_trace_chunk_release(struct urcu_ref *ref)
1872 {
1873         struct lttng_trace_chunk *chunk = container_of(ref, typeof(*chunk),
1874                         ref);
1875
1876         if (chunk->close_command.is_set) {
1877                 chunk_command func = close_command_get_post_release_func(chunk->close_command.value);
1878
1879                 if (func(chunk)) {
1880                         ERR("Trace chunk post-release command %s has failed.",
1881                                         lttng_trace_chunk_command_type_str(chunk->close_command.value));
1882                 }
1883         }
1884
1885         if (chunk->in_registry_element) {
1886                 struct lttng_trace_chunk_registry_element *element;
1887
1888                 /*
1889                  * Release internal chunk attributes immediately and
1890                  * only use the deferred `call_rcu` work to reclaim the
1891                  * storage.
1892                  *
1893                  * This ensures that file handles are released as soon as
1894                  * possible which works around a problem we encounter with PRAM fs
1895                  * mounts (and possibly other non-POSIX compliant file systems):
1896                  * directories that contain files which are open can't be
1897                  * rmdir().
1898                  *
1899                  * This means that the recording of a snapshot could be
1900                  * completed, but that it would be impossible for the user to
1901                  * delete it until the deferred clean-up released the file
1902                  * handles to its contents.
1903                  */
1904                 lttng_trace_chunk_fini(chunk);
1905
1906                 element = container_of(chunk, typeof(*element), chunk);
1907                 if (element->registry) {
1908                         rcu_read_lock();
1909                         cds_lfht_del(element->registry->ht,
1910                                         &element->trace_chunk_registry_ht_node);
1911                         rcu_read_unlock();
1912                         call_rcu(&element->rcu_node,
1913                                         free_lttng_trace_chunk_registry_element);
1914                 } else {
1915                         /* Never published, can be free'd immediately. */
1916                         free_lttng_trace_chunk_registry_element(
1917                                         &element->rcu_node);
1918                 }
1919         } else {
1920                 /* Not RCU-protected, free immediately. */
1921                 lttng_trace_chunk_fini(chunk);
1922                 free(chunk);
1923         }
1924 }
1925
1926 void lttng_trace_chunk_put(struct lttng_trace_chunk *chunk)
1927 {
1928         if (!chunk) {
1929                 return;
1930         }
1931         LTTNG_ASSERT(chunk->ref.refcount);
1932         urcu_ref_put(&chunk->ref, lttng_trace_chunk_release);
1933 }
1934
1935 struct lttng_trace_chunk_registry *lttng_trace_chunk_registry_create(void)
1936 {
1937         struct lttng_trace_chunk_registry *registry;
1938
1939         registry = zmalloc<lttng_trace_chunk_registry>();
1940         if (!registry) {
1941                 goto end;
1942         }
1943
1944         registry->ht = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
1945                         CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
1946         if (!registry->ht) {
1947                 goto error;
1948         }
1949 end:
1950         return registry;
1951 error:
1952         lttng_trace_chunk_registry_destroy(registry);
1953         return NULL;
1954 }
1955
1956 void lttng_trace_chunk_registry_destroy(
1957                 struct lttng_trace_chunk_registry *registry)
1958 {
1959         if (!registry) {
1960                 return;
1961         }
1962         if (registry->ht) {
1963                 int ret = cds_lfht_destroy(registry->ht, NULL);
1964                 LTTNG_ASSERT(!ret);
1965         }
1966         free(registry);
1967 }
1968
1969 static
1970 struct lttng_trace_chunk_registry_element *
1971 lttng_trace_chunk_registry_element_create_from_chunk(
1972                 struct lttng_trace_chunk *chunk, uint64_t session_id)
1973 {
1974         struct lttng_trace_chunk_registry_element *element =
1975                 zmalloc<lttng_trace_chunk_registry_element>();
1976
1977         if (!element) {
1978                 goto end;
1979         }
1980         cds_lfht_node_init(&element->trace_chunk_registry_ht_node);
1981         element->session_id = session_id;
1982
1983         element->chunk = *chunk;
1984         lttng_trace_chunk_init(&element->chunk);
1985         if (chunk->session_output_directory) {
1986                 /* Transferred ownership. */
1987                 element->chunk.session_output_directory =
1988                                 chunk->session_output_directory;
1989                 chunk->session_output_directory = NULL;
1990         }
1991         if (chunk->chunk_directory) {
1992                 /* Transferred ownership. */
1993                 element->chunk.chunk_directory = chunk->chunk_directory;
1994                 chunk->chunk_directory = NULL;
1995         }
1996         /*
1997          * The original chunk becomes invalid; the name and path attributes are
1998          * transferred to the new chunk instance.
1999          */
2000         chunk->name = NULL;
2001         chunk->path = NULL;
2002         element->chunk.fd_tracker = chunk->fd_tracker;
2003         element->chunk.in_registry_element = true;
2004 end:
2005         return element;
2006 }
2007
2008 struct lttng_trace_chunk *
2009 lttng_trace_chunk_registry_publish_chunk(
2010                 struct lttng_trace_chunk_registry *registry,
2011                 uint64_t session_id,
2012                 struct lttng_trace_chunk *chunk)
2013 {
2014         bool unused;
2015
2016         return lttng_trace_chunk_registry_publish_chunk(
2017                         registry, session_id, chunk, &unused);
2018 }
2019
2020 struct lttng_trace_chunk *
2021 lttng_trace_chunk_registry_publish_chunk(
2022                 struct lttng_trace_chunk_registry *registry,
2023                 uint64_t session_id, struct lttng_trace_chunk *chunk,
2024                 bool *previously_published)
2025 {
2026         struct lttng_trace_chunk_registry_element *element;
2027         unsigned long element_hash;
2028
2029         pthread_mutex_lock(&chunk->lock);
2030         element = lttng_trace_chunk_registry_element_create_from_chunk(chunk,
2031                         session_id);
2032         pthread_mutex_unlock(&chunk->lock);
2033         if (!element) {
2034                 goto end;
2035         }
2036         /*
2037          * chunk is now invalid, the only valid operation is a 'put' from the
2038          * caller.
2039          */
2040         chunk = NULL;
2041         element_hash = lttng_trace_chunk_registry_element_hash(element);
2042
2043         rcu_read_lock();
2044         while (1) {
2045                 struct cds_lfht_node *published_node;
2046                 struct lttng_trace_chunk *published_chunk;
2047                 struct lttng_trace_chunk_registry_element *published_element;
2048
2049                 published_node = cds_lfht_add_unique(registry->ht,
2050                                 element_hash,
2051                                 lttng_trace_chunk_registry_element_match,
2052                                 element,
2053                                 &element->trace_chunk_registry_ht_node);
2054                 if (published_node == &element->trace_chunk_registry_ht_node) {
2055                         /* Successfully published the new element. */
2056                         element->registry = registry;
2057                         /* Acquire a reference for the caller. */
2058                         if (lttng_trace_chunk_get(&element->chunk)) {
2059                                 *previously_published = false;
2060                                 break;
2061                         } else {
2062                                 /*
2063                                  * Another thread concurrently unpublished the
2064                                  * trace chunk. This is currently unexpected.
2065                                  *
2066                                  * Re-attempt to publish.
2067                                  */
2068                                 ERR("Attempt to publish a trace chunk to the chunk registry raced with a trace chunk deletion");
2069                                 continue;
2070                         }
2071                 }
2072
2073                 /*
2074                  * An equivalent trace chunk was published before this trace
2075                  * chunk. Attempt to acquire a reference to the one that was
2076                  * already published and release the reference to the copy we
2077                  * created if successful.
2078                  */
2079                 published_element = container_of(published_node,
2080                                 typeof(*published_element),
2081                                 trace_chunk_registry_ht_node);
2082                 published_chunk = &published_element->chunk;
2083                 if (lttng_trace_chunk_get(published_chunk)) {
2084                         lttng_trace_chunk_put(&element->chunk);
2085                         element = published_element;
2086                         *previously_published = true;
2087                         break;
2088                 }
2089                 /*
2090                  * A reference to the previously published trace chunk could not
2091                  * be acquired. Hence, retry to publish our copy of the trace
2092                  * chunk.
2093                  */
2094         }
2095         rcu_read_unlock();
2096 end:
2097         return element ? &element->chunk : NULL;
2098 }
2099
2100 /*
2101  * Note that the caller must be registered as an RCU thread.
2102  * However, it does not need to hold the RCU read lock. The RCU read lock is
2103  * acquired to perform the look-up in the registry's hash table and held until
2104  * after a reference to the "found" trace chunk is acquired.
2105  *
2106  * IOW, holding a reference guarantees the existence of the object for the
2107  * caller.
2108  */
2109 static
2110 struct lttng_trace_chunk *_lttng_trace_chunk_registry_find_chunk(
2111                 const struct lttng_trace_chunk_registry *registry,
2112                 uint64_t session_id, uint64_t *chunk_id)
2113 {
2114         lttng_trace_chunk_registry_element target_element {};
2115
2116         target_element.chunk.id.is_set = !!chunk_id;
2117         target_element.chunk.id.value = chunk_id ? *chunk_id : 0;
2118         target_element.session_id = session_id;
2119
2120         const unsigned long element_hash =
2121                         lttng_trace_chunk_registry_element_hash(
2122                                 &target_element);
2123         struct cds_lfht_node *published_node;
2124         struct lttng_trace_chunk_registry_element *published_element;
2125         struct lttng_trace_chunk *published_chunk = NULL;
2126         struct cds_lfht_iter iter;
2127
2128         rcu_read_lock();
2129         cds_lfht_lookup(registry->ht,
2130                         element_hash,
2131                         lttng_trace_chunk_registry_element_match,
2132                         &target_element,
2133                         &iter);
2134         published_node = cds_lfht_iter_get_node(&iter);
2135         if (!published_node) {
2136                 goto end;
2137         }
2138
2139         published_element = container_of(published_node,
2140                         typeof(*published_element),
2141                         trace_chunk_registry_ht_node);
2142         if (lttng_trace_chunk_get(&published_element->chunk)) {
2143                 published_chunk = &published_element->chunk;
2144         }
2145 end:
2146         rcu_read_unlock();
2147         return published_chunk;
2148 }
2149
2150 struct lttng_trace_chunk *
2151 lttng_trace_chunk_registry_find_chunk(
2152                 const struct lttng_trace_chunk_registry *registry,
2153                 uint64_t session_id, uint64_t chunk_id)
2154 {
2155         return _lttng_trace_chunk_registry_find_chunk(registry,
2156                         session_id, &chunk_id);
2157 }
2158
2159 int lttng_trace_chunk_registry_chunk_exists(
2160                 const struct lttng_trace_chunk_registry *registry,
2161                 uint64_t session_id, uint64_t chunk_id, bool *chunk_exists)
2162 {
2163         int ret = 0;
2164         lttng_trace_chunk_registry_element target_element;
2165
2166         target_element.chunk.id.is_set = true;
2167         target_element.chunk.id.value = chunk_id;
2168         target_element.session_id = session_id;
2169
2170         const unsigned long element_hash =
2171                         lttng_trace_chunk_registry_element_hash(
2172                                 &target_element);
2173         struct cds_lfht_node *published_node;
2174         struct cds_lfht_iter iter;
2175
2176         rcu_read_lock();
2177         cds_lfht_lookup(registry->ht,
2178                         element_hash,
2179                         lttng_trace_chunk_registry_element_match,
2180                         &target_element,
2181                         &iter);
2182         published_node = cds_lfht_iter_get_node(&iter);
2183         if (!published_node) {
2184                 *chunk_exists = false;
2185                 goto end;
2186         }
2187
2188         *chunk_exists = !cds_lfht_is_node_deleted(published_node);
2189 end:
2190         rcu_read_unlock();
2191         return ret;
2192 }
2193
2194 struct lttng_trace_chunk *
2195 lttng_trace_chunk_registry_find_anonymous_chunk(
2196                 const struct lttng_trace_chunk_registry *registry,
2197                 uint64_t session_id)
2198 {
2199         return _lttng_trace_chunk_registry_find_chunk(registry,
2200                         session_id, NULL);
2201 }
2202
2203 unsigned int lttng_trace_chunk_registry_put_each_chunk(
2204                 const struct lttng_trace_chunk_registry *registry)
2205 {
2206         struct cds_lfht_iter iter;
2207         struct lttng_trace_chunk_registry_element *chunk_element;
2208         unsigned int trace_chunks_left = 0;
2209
2210         DBG("Releasing trace chunk registry to all trace chunks");
2211         rcu_read_lock();
2212         cds_lfht_for_each_entry(registry->ht,
2213                         &iter, chunk_element, trace_chunk_registry_ht_node) {
2214                 const char *chunk_id_str = "none";
2215                 char chunk_id_buf[MAX_INT_DEC_LEN(uint64_t)];
2216
2217                 pthread_mutex_lock(&chunk_element->chunk.lock);
2218                 if (chunk_element->chunk.id.is_set) {
2219                         int fmt_ret;
2220
2221                         fmt_ret = snprintf(chunk_id_buf, sizeof(chunk_id_buf),
2222                                         "%" PRIu64,
2223                                         chunk_element->chunk.id.value);
2224                         if (fmt_ret < 0 || fmt_ret >= sizeof(chunk_id_buf)) {
2225                                 chunk_id_str = "formatting error";
2226                         } else {
2227                                 chunk_id_str = chunk_id_buf;
2228                         }
2229                 }
2230
2231                 DBG("Releasing reference to trace chunk: session_id = %" PRIu64
2232                                 "chunk_id = %s, name = \"%s\", status = %s",
2233                                 chunk_element->session_id,
2234                                 chunk_id_str,
2235                                 chunk_element->chunk.name ? : "none",
2236                                 chunk_element->chunk.close_command.is_set ?
2237                                                 "open" : "closed");
2238                 pthread_mutex_unlock(&chunk_element->chunk.lock);
2239                 lttng_trace_chunk_put(&chunk_element->chunk);
2240                 trace_chunks_left++;
2241         }
2242         rcu_read_unlock();
2243         DBG("Released reference to %u trace chunks in %s()", trace_chunks_left,
2244                         __FUNCTION__);
2245
2246         return trace_chunks_left;
2247 }