src/bin/lttng-sessiond/rotation-thread.c

   1 /*
   2  * Copyright (C) 2017 - Julien Desfossez <jdesfossez@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _LGPL_SOURCE
  19 #include <lttng/trigger/trigger.h>
  20 #include <common/error.h>
  21 #include <common/config/session-config.h>
  22 #include <common/defaults.h>
  23 #include <common/utils.h>
  24 #include <common/futex.h>
  25 #include <common/align.h>
  26 #include <common/time.h>
  27 #include <common/hashtable/utils.h>
  28 #include <sys/eventfd.h>
  29 #include <sys/stat.h>
  30 #include <time.h>
  31 #include <signal.h>
  32 #include <inttypes.h>
  33
  34 #include <common/kernel-ctl/kernel-ctl.h>
  35 #include <lttng/notification/channel-internal.h>
  36 #include <lttng/rotate-internal.h>
  37
  38 #include "rotation-thread.h"
  39 #include "lttng-sessiond.h"
  40 #include "health-sessiond.h"
  41 #include "rotate.h"
  42 #include "cmd.h"
  43 #include "session.h"
  44 #include "sessiond-timer.h"
  45
  46 #include <urcu.h>
  47 #include <urcu/list.h>
  48 #include <urcu/rculfhash.h>
  49
  50 /*
  51  * Store a struct rotation_channel_info for each channel that is currently
  52  * being rotated by the consumer.
  53  */
  54 struct cds_lfht *channel_pending_rotate_ht;
  55
  56 struct lttng_notification_channel *rotate_notification_channel = NULL;
  57
  58 struct rotation_thread_state {
  59         struct lttng_poll_event events;
  60 };
  61
  62 static
  63 void channel_rotation_info_destroy(struct rotation_channel_info *channel_info)
  64 {
  65         assert(channel_info);
  66         free(channel_info);
  67 }
  68
  69 static
  70 int match_channel_info(struct cds_lfht_node *node, const void *key)
  71 {
  72         struct rotation_channel_key *channel_key = (struct rotation_channel_key *) key;
  73         struct rotation_channel_info *channel_info;
  74
  75         channel_info = caa_container_of(node, struct rotation_channel_info,
  76                         rotate_channels_ht_node);
  77
  78         return !!((channel_key->key == channel_info->channel_key.key) &&
  79                         (channel_key->domain == channel_info->channel_key.domain));
  80 }
  81
  82 static
  83 struct rotation_channel_info *lookup_channel_pending(uint64_t key,
  84                 enum lttng_domain_type domain)
  85 {
  86         struct cds_lfht_iter iter;
  87         struct cds_lfht_node *node;
  88         struct rotation_channel_info *channel_info = NULL;
  89         struct rotation_channel_key channel_key = { .key = key,
  90                         .domain = domain };
  91
  92         cds_lfht_lookup(channel_pending_rotate_ht,
  93                         hash_channel_key(&channel_key),
  94                         match_channel_info,
  95                         &channel_key, &iter);
  96         node = cds_lfht_iter_get_node(&iter);
  97         if (!node) {
  98                 goto end;
  99         }
 100
 101         channel_info = caa_container_of(node, struct rotation_channel_info,
 102                         rotate_channels_ht_node);
 103         cds_lfht_del(channel_pending_rotate_ht, node);
 104 end:
 105         return channel_info;
 106 }
 107
 108 /*
 109  * Destroy the thread data previously created by the init function.
 110  */
 111 void rotation_thread_handle_destroy(
 112                 struct rotation_thread_handle *handle)
 113 {
 114         int ret;
 115
 116         if (!handle) {
 117                 goto end;
 118         }
 119
 120         if (handle->ust32_consumer >= 0) {
 121                 ret = close(handle->ust32_consumer);
 122                 if (ret) {
 123                         PERROR("close 32-bit consumer channel rotation pipe");
 124                 }
 125         }
 126         if (handle->ust64_consumer >= 0) {
 127                 ret = close(handle->ust64_consumer);
 128                 if (ret) {
 129                         PERROR("close 64-bit consumer channel rotation pipe");
 130                 }
 131         }
 132         if (handle->kernel_consumer >= 0) {
 133                 ret = close(handle->kernel_consumer);
 134                 if (ret) {
 135                         PERROR("close kernel consumer channel rotation pipe");
 136                 }
 137         }
 138
 139 end:
 140         free(handle);
 141 }
 142
 143 struct rotation_thread_handle *rotation_thread_handle_create(
 144                 struct lttng_pipe *ust32_channel_rotate_pipe,
 145                 struct lttng_pipe *ust64_channel_rotate_pipe,
 146                 struct lttng_pipe *kernel_channel_rotate_pipe,
 147                 int thread_quit_pipe,
 148                 struct rotation_thread_timer_queue *rotation_timer_queue,
 149                 struct notification_thread_handle *notification_thread_handle,
 150                 sem_t *notification_thread_ready)
 151 {
 152         struct rotation_thread_handle *handle;
 153
 154         handle = zmalloc(sizeof(*handle));
 155         if (!handle) {
 156                 goto end;
 157         }
 158
 159         if (ust32_channel_rotate_pipe) {
 160                 handle->ust32_consumer =
 161                                 lttng_pipe_release_readfd(
 162                                         ust32_channel_rotate_pipe);
 163                 if (handle->ust32_consumer < 0) {
 164                         goto error;
 165                 }
 166         } else {
 167                 handle->ust32_consumer = -1;
 168         }
 169         if (ust64_channel_rotate_pipe) {
 170                 handle->ust64_consumer =
 171                                 lttng_pipe_release_readfd(
 172                                         ust64_channel_rotate_pipe);
 173                 if (handle->ust64_consumer < 0) {
 174                         goto error;
 175                 }
 176         } else {
 177                 handle->ust64_consumer = -1;
 178         }
 179         if (kernel_channel_rotate_pipe) {
 180                 handle->kernel_consumer =
 181                                 lttng_pipe_release_readfd(
 182                                         kernel_channel_rotate_pipe);
 183                 if (handle->kernel_consumer < 0) {
 184                         goto error;
 185                 }
 186         } else {
 187                 handle->kernel_consumer = -1;
 188         }
 189         handle->thread_quit_pipe = thread_quit_pipe;
 190         handle->rotation_timer_queue = rotation_timer_queue;
 191         handle->notification_thread_handle = notification_thread_handle;
 192         handle->notification_thread_ready = notification_thread_ready;
 193
 194 end:
 195         return handle;
 196 error:
 197         rotation_thread_handle_destroy(handle);
 198         return NULL;
 199 }
 200
 201 static
 202 int init_poll_set(struct lttng_poll_event *poll_set,
 203                 struct rotation_thread_handle *handle)
 204 {
 205         int ret;
 206
 207         /*
 208          * Create pollset with size 5:
 209          *      - sessiond quit pipe
 210          *      - sessiond timer pipe,
 211          *      - consumerd (32-bit user space) channel rotate pipe,
 212          *      - consumerd (64-bit user space) channel rotate pipe,
 213          *      - consumerd (kernel) channel rotate pipe,
 214          */
 215         ret = lttng_poll_create(poll_set, 5, LTTNG_CLOEXEC);
 216         if (ret < 0) {
 217                 goto end;
 218         }
 219
 220         ret = lttng_poll_add(poll_set, handle->thread_quit_pipe,
 221                         LPOLLIN | LPOLLERR);
 222         if (ret < 0) {
 223                 ERR("[rotation-thread] Failed to add thread_quit_pipe fd to pollset");
 224                 goto error;
 225         }
 226         ret = lttng_poll_add(poll_set,
 227                         lttng_pipe_get_readfd(handle->rotation_timer_queue->event_pipe),
 228                         LPOLLIN | LPOLLERR);
 229         if (ret < 0) {
 230                 ERR("[rotation-thread] Failed to add rotate_pending fd to pollset");
 231                 goto error;
 232         }
 233         ret = lttng_poll_add(poll_set, handle->ust32_consumer,
 234                         LPOLLIN | LPOLLERR);
 235         if (ret < 0) {
 236                 ERR("[rotation-thread] Failed to add ust-32 channel rotation pipe fd to pollset");
 237                 goto error;
 238         }
 239         ret = lttng_poll_add(poll_set, handle->ust64_consumer,
 240                         LPOLLIN | LPOLLERR);
 241         if (ret < 0) {
 242                 ERR("[rotation-thread] Failed to add ust-64 channel rotation pipe fd to pollset");
 243                 goto error;
 244         }
 245         if (handle->kernel_consumer >= 0) {
 246                 ret = lttng_poll_add(poll_set, handle->kernel_consumer,
 247                                 LPOLLIN | LPOLLERR);
 248                 if (ret < 0) {
 249                         ERR("[rotation-thread] Failed to add kernel channel rotation pipe fd to pollset");
 250                         goto error;
 251                 }
 252         }
 253
 254 end:
 255         return ret;
 256 error:
 257         lttng_poll_clean(poll_set);
 258         return ret;
 259 }
 260
 261 static
 262 void fini_thread_state(struct rotation_thread_state *state)
 263 {
 264         int ret;
 265
 266         lttng_poll_clean(&state->events);
 267         ret = cds_lfht_destroy(channel_pending_rotate_ht, NULL);
 268         assert(!ret);
 269         if (rotate_notification_channel) {
 270                 lttng_notification_channel_destroy(rotate_notification_channel);
 271         }
 272 }
 273
 274 static
 275 int init_thread_state(struct rotation_thread_handle *handle,
 276                 struct rotation_thread_state *state)
 277 {
 278         int ret;
 279
 280         memset(state, 0, sizeof(*state));
 281         lttng_poll_init(&state->events);
 282
 283         ret = init_poll_set(&state->events, handle);
 284         if (ret) {
 285                 ERR("[rotation-thread] Failed to initialize rotation thread poll set");
 286                 goto end;
 287         }
 288
 289         channel_pending_rotate_ht = cds_lfht_new(DEFAULT_HT_SIZE,
 290                         1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
 291         if (!channel_pending_rotate_ht) {
 292                 ERR("[rotation-thread] Failed to create channel pending rotation hash table");
 293                 ret = -1;
 294                 goto end;
 295         }
 296
 297         /*
 298          * We wait until the notification thread is ready to create the
 299          * notification channel and add it to the poll_set.
 300          */
 301         sem_wait(handle->notification_thread_ready);
 302         rotate_notification_channel = lttng_notification_channel_create(
 303                         lttng_session_daemon_notification_endpoint);
 304         if (!rotate_notification_channel) {
 305                 ERR("[rotation-thread] Could not create notification channel");
 306                 ret = -1;
 307                 goto end;
 308         }
 309         ret = lttng_poll_add(&state->events, rotate_notification_channel->socket,
 310                         LPOLLIN | LPOLLERR);
 311         if (ret < 0) {
 312                 ERR("[rotation-thread] Failed to add notification fd to pollset");
 313                 goto end;
 314         }
 315
 316 end:
 317         return ret;
 318 }
 319
 320 static
 321 int handle_channel_rotation_pipe(int fd, uint32_t revents,
 322                 struct rotation_thread_handle *handle,
 323                 struct rotation_thread_state *state)
 324 {
 325         int ret = 0;
 326         enum lttng_domain_type domain;
 327         struct rotation_channel_info *channel_info;
 328         struct ltt_session *session = NULL;
 329         uint64_t key;
 330
 331         if (fd == handle->ust32_consumer ||
 332                         fd == handle->ust64_consumer) {
 333                 domain = LTTNG_DOMAIN_UST;
 334         } else if (fd == handle->kernel_consumer) {
 335                 domain = LTTNG_DOMAIN_KERNEL;
 336         } else {
 337                 ERR("[rotation-thread] Unknown channel rotation pipe fd %d",
 338                                 fd);
 339                 abort();
 340         }
 341
 342         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 343                 ret = lttng_poll_del(&state->events, fd);
 344                 if (ret) {
 345                         ERR("[rotation-thread] Failed to remove consumer "
 346                                         "rotation pipe from poll set");
 347                 }
 348                 goto end;
 349         }
 350
 351         do {
 352                 ret = read(fd, &key, sizeof(key));
 353         } while (ret == -1 && errno == EINTR);
 354         if (ret != sizeof(key)) {
 355                 ERR("[rotation-thread] Failed to read from pipe (fd = %i)",
 356                                 fd);
 357                 ret = -1;
 358                 goto end;
 359         }
 360
 361         DBG("[rotation-thread] Received notification for chan %" PRIu64
 362                         ", domain %d", key, domain);
 363
 364         channel_info = lookup_channel_pending(key, domain);
 365         if (!channel_info) {
 366                 ERR("[rotation-thread] Failed to find channel_info (key = %"
 367                                 PRIu64 ")", key);
 368                 ret = -1;
 369                 goto end;
 370         }
 371         rcu_read_lock();
 372         session_lock_list();
 373         session = session_find_by_id(channel_info->session_id);
 374         if (!session) {
 375                 /*
 376                  * The session may have been destroyed before we had a chance to
 377                  * perform this action, return gracefully.
 378                  */
 379                 DBG("[rotation-thread] Session %" PRIu64 " not found",
 380                                 channel_info->session_id);
 381                 ret = 0;
 382                 goto end_unlock_session_list;
 383         }
 384
 385         session_lock(session);
 386         if (--session->nr_chan_rotate_pending == 0) {
 387                 time_t now = time(NULL);
 388
 389                 if (now == (time_t) -1) {
 390                         session->rotation_state = LTTNG_ROTATION_STATE_ERROR;
 391                         ret = LTTNG_ERR_UNK;
 392                         goto end_unlock_session;
 393                 }
 394
 395                 ret = rename_complete_chunk(session, now);
 396                 if (ret < 0) {
 397                         ERR("Failed to rename completed rotation chunk");
 398                         goto end_unlock_session;
 399                 }
 400                 session->rotate_pending = false;
 401                 session->last_chunk_start_ts = session->current_chunk_start_ts;
 402                 if (session->rotate_pending_relay) {
 403                         ret = sessiond_timer_rotate_pending_start(
 404                                         session,
 405                                         DEFAULT_ROTATE_PENDING_RELAY_TIMER);
 406                         if (ret) {
 407                                 ERR("Failed to enable rotate pending timer");
 408                                 ret = -1;
 409                                 goto end_unlock_session;
 410                         }
 411                 } else {
 412                         session->rotation_state = LTTNG_ROTATION_STATE_COMPLETED;
 413                 }
 414                 DBG("Rotation completed for session %s", session->name);
 415         }
 416
 417         ret = 0;
 418
 419 end_unlock_session:
 420         channel_rotation_info_destroy(channel_info);
 421         session_unlock(session);
 422 end_unlock_session_list:
 423         session_unlock_list();
 424         rcu_read_unlock();
 425 end:
 426         return ret;
 427 }
 428
 429 /*
 430  * Process the rotate_pending check, called with session lock held.
 431  */
 432 static
 433 int rotate_pending_relay_timer(struct ltt_session *session)
 434 {
 435         int ret;
 436
 437         DBG("[rotation-thread] Check rotate pending on session %" PRIu64,
 438                         session->id);
 439         ret = relay_rotate_pending(session, session->current_archive_id - 1);
 440         if (ret < 0) {
 441                 ERR("[rotation-thread] Check relay rotate pending");
 442                 goto end;
 443         }
 444         if (ret == 0) {
 445                 DBG("[rotation-thread] Rotation completed on the relay for "
 446                                 "session %" PRIu64, session->id);
 447                 /*
 448                  * Now we can clear the pending flag in the session. New
 449                  * rotations can start now.
 450                  */
 451                 session->rotate_pending_relay = false;
 452                 session->rotation_state = LTTNG_ROTATION_STATE_COMPLETED;
 453         } else if (ret == 1) {
 454                 DBG("[rotation-thread] Rotation still pending on the relay for "
 455                                 "session %" PRIu64, session->id);
 456                 ret = sessiond_timer_rotate_pending_start(session,
 457                                 DEFAULT_ROTATE_PENDING_RELAY_TIMER);
 458                 if (ret) {
 459                         ERR("Re-enabling rotate pending timer");
 460                         ret = -1;
 461                         goto end;
 462                 }
 463         }
 464
 465         ret = 0;
 466
 467 end:
 468         return ret;
 469 }
 470
 471 /*
 472  * Process the rotate_timer, called with session lock held.
 473  */
 474 static
 475 int rotate_timer(struct ltt_session *session)
 476 {
 477         int ret;
 478
 479         /*
 480          * Complete _at most_ one scheduled rotation on a stopped session.
 481          */
 482         if (!session->active && session->rotate_timer_enabled &&
 483                         session->rotated_after_last_stop) {
 484                 ret = 0;
 485                 goto end;
 486         }
 487
 488         /* Ignore this timer if a rotation is already in progress. */
 489         if (session->rotate_pending || session->rotate_pending_relay) {
 490                 ret = 0;
 491                 goto end;
 492         }
 493
 494         DBG("[rotation-thread] Rotate timer on session %s", session->name);
 495
 496         ret = cmd_rotate_session(session, NULL);
 497         if (ret == -LTTNG_ERR_ROTATION_PENDING) {
 498                 DBG("Scheduled rotation aborted since a rotation is already in progress");
 499                 ret = 0;
 500                 goto end;
 501         } else if (ret != LTTNG_OK) {
 502                 ERR("[rotation-thread] Automatic time-triggered rotation failed with error code %i", ret);
 503                 ret = -1;
 504                 goto end;
 505         }
 506
 507         ret = 0;
 508
 509 end:
 510         return ret;
 511 }
 512
 513 static
 514 int handle_rotate_timer_pipe(uint32_t revents,
 515                 struct rotation_thread_handle *handle,
 516                 struct rotation_thread_state *state,
 517                 struct rotation_thread_timer_queue *queue)
 518 {
 519         int ret = 0;
 520         int fd = lttng_pipe_get_readfd(queue->event_pipe);
 521         struct ltt_session *session;
 522         char buf[1];
 523
 524         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 525                 ret = lttng_poll_del(&state->events, fd);
 526                 if (ret) {
 527                         ERR("[rotation-thread] Failed to remove consumer "
 528                                         "rotate pending pipe from poll set");
 529                 }
 530                 goto end;
 531         }
 532
 533         ret = lttng_read(fd, buf, 1);
 534         if (ret != 1) {
 535                 ERR("[rotation-thread] Failed to read from wakeup pipe (fd = %i)", fd);
 536                 ret = -1;
 537                 goto end;
 538         }
 539
 540         for (;;) {
 541                 struct sessiond_rotation_timer *timer_data;
 542
 543                 /*
 544                  * Take the queue lock only to pop elements from the list.
 545                  */
 546                 pthread_mutex_lock(&queue->lock);
 547                 if (cds_list_empty(&queue->list)) {
 548                         pthread_mutex_unlock(&queue->lock);
 549                         break;
 550                 }
 551                 timer_data = cds_list_first_entry(&queue->list,
 552                                 struct sessiond_rotation_timer, head);
 553                 cds_list_del(&timer_data->head);
 554                 pthread_mutex_unlock(&queue->lock);
 555
 556                 /*
 557                  * session lock to lookup the session ID.
 558                  */
 559                 session_lock_list();
 560                 session = session_find_by_id(timer_data->session_id);
 561                 if (!session) {
 562                         DBG("[rotation-thread] Session %" PRIu64 " not found",
 563                                         timer_data->session_id);
 564                         /*
 565                          * This is a non-fatal error, and we cannot report it to the
 566                          * user (timer), so just print the error and continue the
 567                          * processing.
 568                          */
 569                         session_unlock_list();
 570                         free(timer_data);
 571                         continue;
 572                 }
 573
 574                 /*
 575                  * Take the session lock and release the session_list lock.
 576                  */
 577                 session_lock(session);
 578                 session_unlock_list();
 579
 580                 if (timer_data->signal == LTTNG_SESSIOND_SIG_ROTATE_PENDING) {
 581                         ret = rotate_pending_relay_timer(session);
 582                 } else if (timer_data->signal == LTTNG_SESSIOND_SIG_ROTATE_TIMER) {
 583                         ret = rotate_timer(session);
 584                 } else {
 585                         ERR("Unknown signal in rotate timer %d", timer_data->signal);
 586                         ret = -1;
 587                 }
 588                 session_unlock(session);
 589                 free(timer_data);
 590                 if (ret) {
 591                         ERR("Error processing timer");
 592                         goto end;
 593                 }
 594         }
 595
 596         ret = 0;
 597
 598 end:
 599         return ret;
 600 }
 601
 602 int handle_condition(
 603                 const struct lttng_condition *condition,
 604                 const struct lttng_evaluation *evaluation,
 605                 struct notification_thread_handle *notification_thread_handle)
 606 {
 607         int ret = 0;
 608         const char *condition_session_name = NULL;
 609         enum lttng_condition_type condition_type;
 610         enum lttng_condition_status condition_status;
 611         enum lttng_evaluation_status evaluation_status;
 612         uint64_t consumed;
 613         struct ltt_session *session;
 614
 615         condition_type = lttng_condition_get_type(condition);
 616
 617         if (condition_type != LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE) {
 618                 ret = -1;
 619                 ERR("[rotation-thread] Condition type and session usage type are not the same");
 620                 goto end;
 621         }
 622
 623         /* Fetch info to test */
 624         condition_status = lttng_condition_session_consumed_size_get_session_name(
 625                         condition, &condition_session_name);
 626         if (condition_status != LTTNG_CONDITION_STATUS_OK) {
 627                 ERR("[rotation-thread] Session name could not be fetched");
 628                 ret = -1;
 629                 goto end;
 630         }
 631         evaluation_status = lttng_evaluation_session_consumed_size_get_consumed_size(evaluation,
 632                         &consumed);
 633         if (evaluation_status != LTTNG_EVALUATION_STATUS_OK) {
 634                 ERR("[rotation-thread] Failed to get evaluation");
 635                 ret = -1;
 636                 goto end;
 637         }
 638
 639         session_lock_list();
 640         session = session_find_by_name(condition_session_name);
 641         if (!session) {
 642                 ret = -1;
 643                 session_unlock_list();
 644                 ERR("[rotation-thread] Session \"%s\" not found",
 645                                 condition_session_name);
 646                 goto end;
 647         }
 648         session_lock(session);
 649         session_unlock_list();
 650
 651         ret = unsubscribe_session_consumed_size_rotation(session,
 652                         notification_thread_handle);
 653         if (ret) {
 654                 goto end;
 655         }
 656
 657         ret = cmd_rotate_session(session, NULL);
 658         if (ret == -LTTNG_ERR_ROTATION_PENDING) {
 659                 DBG("Rotate already pending, subscribe to the next threshold value");
 660                 ret = 0;
 661         } else if (ret != LTTNG_OK) {
 662                 ERR("[rotation-thread] Failed to rotate on size notification with error: %s",
 663                                 lttng_strerror(ret));
 664                 ret = -1;
 665                 goto end_unlock;
 666         }
 667         ret = subscribe_session_consumed_size_rotation(session,
 668                         consumed + session->rotate_size,
 669                         notification_thread_handle);
 670         if (ret) {
 671                 ERR("[rotation-thread] Failed to subscribe to session consumed size condition");
 672                 goto end_unlock;
 673         }
 674         ret = 0;
 675
 676 end_unlock:
 677         session_unlock(session);
 678 end:
 679         return ret;
 680 }
 681
 682 static
 683 int handle_notification_channel(int fd, uint32_t revents,
 684                 struct rotation_thread_handle *handle,
 685                 struct rotation_thread_state *state)
 686 {
 687         int ret;
 688         bool notification_pending;
 689         struct lttng_notification *notification = NULL;
 690         enum lttng_notification_channel_status status;
 691         const struct lttng_evaluation *notification_evaluation;
 692         const struct lttng_condition *notification_condition;
 693
 694         status = lttng_notification_channel_has_pending_notification(
 695                         rotate_notification_channel, &notification_pending);
 696         if (status != LTTNG_NOTIFICATION_CHANNEL_STATUS_OK) {
 697                 ERR("[rotation-thread ]Error occured while checking for pending notification");
 698                 ret = -1;
 699                 goto end;
 700         }
 701
 702         if (!notification_pending) {
 703                 ret = 0;
 704                 goto end;
 705         }
 706
 707         /* Receive the next notification. */
 708         status = lttng_notification_channel_get_next_notification(
 709                         rotate_notification_channel,
 710                         &notification);
 711
 712         switch (status) {
 713         case LTTNG_NOTIFICATION_CHANNEL_STATUS_OK:
 714                 break;
 715         case LTTNG_NOTIFICATION_CHANNEL_STATUS_NOTIFICATIONS_DROPPED:
 716                 /* Not an error, we will wait for the next one */
 717                 ret = 0;
 718                 goto end;;
 719         case LTTNG_NOTIFICATION_CHANNEL_STATUS_CLOSED:
 720                 ERR("Notification channel was closed");
 721                 ret = -1;
 722                 goto end;
 723         default:
 724                 /* Unhandled conditions / errors. */
 725                 ERR("Unknown notification channel status");
 726                 ret = -1;
 727                 goto end;
 728         }
 729
 730         notification_condition = lttng_notification_get_condition(notification);
 731         notification_evaluation = lttng_notification_get_evaluation(notification);
 732
 733         ret = handle_condition(notification_condition, notification_evaluation,
 734                         handle->notification_thread_handle);
 735
 736 end:
 737         lttng_notification_destroy(notification);
 738         return ret;
 739 }
 740
 741 void *thread_rotation(void *data)
 742 {
 743         int ret;
 744         struct rotation_thread_handle *handle = data;
 745         struct rotation_thread_state state;
 746
 747         DBG("[rotation-thread] Started rotation thread");
 748
 749         if (!handle) {
 750                 ERR("[rotation-thread] Invalid thread context provided");
 751                 goto end;
 752         }
 753
 754         rcu_register_thread();
 755         rcu_thread_online();
 756
 757         health_register(health_sessiond, HEALTH_SESSIOND_TYPE_ROTATION);
 758         health_code_update();
 759
 760         ret = init_thread_state(handle, &state);
 761         if (ret) {
 762                 goto end;
 763         }
 764
 765         /* Ready to handle client connections. */
 766         sessiond_notify_ready();
 767
 768         while (true) {
 769                 int fd_count, i;
 770
 771                 health_poll_entry();
 772                 DBG("[rotation-thread] Entering poll wait");
 773                 ret = lttng_poll_wait(&state.events, -1);
 774                 DBG("[rotation-thread] Poll wait returned (%i)", ret);
 775                 health_poll_exit();
 776                 if (ret < 0) {
 777                         /*
 778                          * Restart interrupted system call.
 779                          */
 780                         if (errno == EINTR) {
 781                                 continue;
 782                         }
 783                         ERR("[rotation-thread] Error encountered during lttng_poll_wait (%i)", ret);
 784                         goto error;
 785                 }
 786
 787                 fd_count = ret;
 788                 for (i = 0; i < fd_count; i++) {
 789                         int fd = LTTNG_POLL_GETFD(&state.events, i);
 790                         uint32_t revents = LTTNG_POLL_GETEV(&state.events, i);
 791
 792                         DBG("[rotation-thread] Handling fd (%i) activity (%u)",
 793                                         fd, revents);
 794
 795                         if (fd == handle->thread_quit_pipe) {
 796                                 DBG("[rotation-thread] Quit pipe activity");
 797                                 goto exit;
 798                         } else if (fd == lttng_pipe_get_readfd(handle->rotation_timer_queue->event_pipe)) {
 799                                 ret = handle_rotate_timer_pipe(revents,
 800                                                 handle, &state, handle->rotation_timer_queue);
 801                                 if (ret) {
 802                                         ERR("[rotation-thread] Failed to handle rotation timer pipe event");
 803                                         goto error;
 804                                 }
 805                         } else if (fd == handle->ust32_consumer ||
 806                                         fd == handle->ust64_consumer ||
 807                                         fd == handle->kernel_consumer) {
 808                                 ret = handle_channel_rotation_pipe(fd,
 809                                                 revents, handle, &state);
 810                                 if (ret) {
 811                                         ERR("[rotation-thread] Failed to handle channel rotation pipe");
 812                                         goto error;
 813                                 }
 814                         } else if (fd == rotate_notification_channel->socket) {
 815                                 ret = handle_notification_channel(fd, revents,
 816                                                 handle, &state);
 817                                 if (ret) {
 818                                         ERR("[rotation-thread] Error occured while handling activity on notification channel socket");
 819                                         goto error;
 820                                 }
 821                         }
 822                 }
 823         }
 824 exit:
 825 error:
 826         DBG("[rotation-thread] Exit");
 827         fini_thread_state(&state);
 828         health_unregister(health_sessiond);
 829         rcu_thread_offline();
 830         rcu_unregister_thread();
 831 end:
 832         return NULL;
 833 }