src/common/trace-chunk.c

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