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
  37 #include "rotation-thread.h"
  38 #include "lttng-sessiond.h"
  39 #include "health-sessiond.h"
  40 #include "rotate.h"
  41 #include "cmd.h"
  42 #include "session.h"
  43
  44 #include <urcu.h>
  45 #include <urcu/list.h>
  46 #include <urcu/rculfhash.h>
  47
  48 /*
  49  * Store a struct rotation_channel_info for each channel that is currently
  50  * being rotated by the consumer.
  51  */
  52 struct cds_lfht *channel_pending_rotate_ht;
  53
  54 struct rotation_thread_state {
  55         struct lttng_poll_event events;
  56 };
  57
  58 static
  59 void channel_rotation_info_destroy(struct rotation_channel_info *channel_info)
  60 {
  61         assert(channel_info);
  62         free(channel_info);
  63 }
  64
  65 static
  66 int match_channel_info(struct cds_lfht_node *node, const void *key)
  67 {
  68         struct rotation_channel_key *channel_key = (struct rotation_channel_key *) key;
  69         struct rotation_channel_info *channel_info;
  70
  71         channel_info = caa_container_of(node, struct rotation_channel_info,
  72                         rotate_channels_ht_node);
  73
  74         return !!((channel_key->key == channel_info->channel_key.key) &&
  75                         (channel_key->domain == channel_info->channel_key.domain));
  76 }
  77
  78 static
  79 struct rotation_channel_info *lookup_channel_pending(uint64_t key,
  80                 enum lttng_domain_type domain)
  81 {
  82         struct cds_lfht_iter iter;
  83         struct cds_lfht_node *node;
  84         struct rotation_channel_info *channel_info = NULL;
  85         struct rotation_channel_key channel_key = { .key = key,
  86                         .domain = domain };
  87
  88         cds_lfht_lookup(channel_pending_rotate_ht,
  89                         hash_channel_key(&channel_key),
  90                         match_channel_info,
  91                         &channel_key, &iter);
  92         node = cds_lfht_iter_get_node(&iter);
  93         if (!node) {
  94                 goto end;
  95         }
  96
  97         channel_info = caa_container_of(node, struct rotation_channel_info,
  98                         rotate_channels_ht_node);
  99         cds_lfht_del(channel_pending_rotate_ht, node);
 100 end:
 101         return channel_info;
 102 }
 103
 104 /*
 105  * Destroy the thread data previously created by the init function.
 106  */
 107 void rotation_thread_handle_destroy(
 108                 struct rotation_thread_handle *handle)
 109 {
 110         int ret;
 111
 112         if (!handle) {
 113                 goto end;
 114         }
 115
 116         if (handle->ust32_consumer >= 0) {
 117                 ret = close(handle->ust32_consumer);
 118                 if (ret) {
 119                         PERROR("close 32-bit consumer channel rotation pipe");
 120                 }
 121         }
 122         if (handle->ust64_consumer >= 0) {
 123                 ret = close(handle->ust64_consumer);
 124                 if (ret) {
 125                         PERROR("close 64-bit consumer channel rotation pipe");
 126                 }
 127         }
 128         if (handle->kernel_consumer >= 0) {
 129                 ret = close(handle->kernel_consumer);
 130                 if (ret) {
 131                         PERROR("close kernel consumer channel rotation pipe");
 132                 }
 133         }
 134
 135 end:
 136         free(handle);
 137 }
 138
 139 struct rotation_thread_handle *rotation_thread_handle_create(
 140                 struct lttng_pipe *ust32_channel_rotate_pipe,
 141                 struct lttng_pipe *ust64_channel_rotate_pipe,
 142                 struct lttng_pipe *kernel_channel_rotate_pipe,
 143                 int thread_quit_pipe)
 144 {
 145         struct rotation_thread_handle *handle;
 146
 147         handle = zmalloc(sizeof(*handle));
 148         if (!handle) {
 149                 goto end;
 150         }
 151
 152         if (ust32_channel_rotate_pipe) {
 153                 handle->ust32_consumer =
 154                                 lttng_pipe_release_readfd(
 155                                         ust32_channel_rotate_pipe);
 156                 if (handle->ust32_consumer < 0) {
 157                         goto error;
 158                 }
 159         } else {
 160                 handle->ust32_consumer = -1;
 161         }
 162         if (ust64_channel_rotate_pipe) {
 163                 handle->ust64_consumer =
 164                                 lttng_pipe_release_readfd(
 165                                         ust64_channel_rotate_pipe);
 166                 if (handle->ust64_consumer < 0) {
 167                         goto error;
 168                 }
 169         } else {
 170                 handle->ust64_consumer = -1;
 171         }
 172         if (kernel_channel_rotate_pipe) {
 173                 handle->kernel_consumer =
 174                                 lttng_pipe_release_readfd(
 175                                         kernel_channel_rotate_pipe);
 176                 if (handle->kernel_consumer < 0) {
 177                         goto error;
 178                 }
 179         } else {
 180                 handle->kernel_consumer = -1;
 181         }
 182         handle->thread_quit_pipe = thread_quit_pipe;
 183
 184 end:
 185         return handle;
 186 error:
 187         rotation_thread_handle_destroy(handle);
 188         return NULL;
 189 }
 190
 191 static
 192 int init_poll_set(struct lttng_poll_event *poll_set,
 193                 struct rotation_thread_handle *handle)
 194 {
 195         int ret;
 196
 197         /*
 198          * Create pollset with size 4:
 199          *      - sessiond quit pipe
 200          *      - consumerd (32-bit user space) channel rotate pipe,
 201          *      - consumerd (64-bit user space) channel rotate pipe,
 202          *      - consumerd (kernel) channel rotate pipe,
 203          */
 204         ret = lttng_poll_create(poll_set, 4, LTTNG_CLOEXEC);
 205         if (ret < 0) {
 206                 goto end;
 207         }
 208
 209         ret = lttng_poll_add(poll_set, handle->thread_quit_pipe,
 210                         LPOLLIN | LPOLLERR);
 211         if (ret < 0) {
 212                 ERR("[rotation-thread] Failed to add thread_quit_pipe fd to pollset");
 213                 goto error;
 214         }
 215         ret = lttng_poll_add(poll_set, handle->ust32_consumer,
 216                         LPOLLIN | LPOLLERR);
 217         if (ret < 0) {
 218                 ERR("[rotation-thread] Failed to add ust-32 channel rotation pipe fd to pollset");
 219                 goto error;
 220         }
 221         ret = lttng_poll_add(poll_set, handle->ust64_consumer,
 222                         LPOLLIN | LPOLLERR);
 223         if (ret < 0) {
 224                 ERR("[rotation-thread] Failed to add ust-64 channel rotation pipe fd to pollset");
 225                 goto error;
 226         }
 227         if (handle->kernel_consumer >= 0) {
 228                 ret = lttng_poll_add(poll_set, handle->kernel_consumer,
 229                                 LPOLLIN | LPOLLERR);
 230                 if (ret < 0) {
 231                         ERR("[rotation-thread] Failed to add kernel channel rotation pipe fd to pollset");
 232                         goto error;
 233                 }
 234         }
 235
 236 end:
 237         return ret;
 238 error:
 239         lttng_poll_clean(poll_set);
 240         return ret;
 241 }
 242
 243 static
 244 void fini_thread_state(struct rotation_thread_state *state)
 245 {
 246         lttng_poll_clean(&state->events);
 247         cds_lfht_destroy(channel_pending_rotate_ht, NULL);
 248 }
 249
 250 static
 251 int init_thread_state(struct rotation_thread_handle *handle,
 252                 struct rotation_thread_state *state)
 253 {
 254         int ret;
 255
 256         memset(state, 0, sizeof(*state));
 257         lttng_poll_init(&state->events);
 258
 259         ret = init_poll_set(&state->events, handle);
 260         if (ret) {
 261                 ERR("[rotation-thread] Failed to initialize rotation thread poll set");
 262                 goto end;
 263         }
 264
 265         channel_pending_rotate_ht = cds_lfht_new(DEFAULT_HT_SIZE,
 266                         1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
 267         if (!channel_pending_rotate_ht) {
 268                 ERR("[rotation-thread] Failed to create channel pending rotation hash table");
 269                 ret = -1;
 270                 goto end;
 271         }
 272
 273 end:
 274         return ret;
 275 }
 276
 277 static
 278 int handle_channel_rotation_pipe(int fd, uint32_t revents,
 279                 struct rotation_thread_handle *handle,
 280                 struct rotation_thread_state *state)
 281 {
 282         int ret = 0;
 283         enum lttng_domain_type domain;
 284         struct rotation_channel_info *channel_info;
 285         struct ltt_session *session = NULL;
 286         uint64_t key;
 287
 288         if (fd == handle->ust32_consumer ||
 289                         fd == handle->ust64_consumer) {
 290                 domain = LTTNG_DOMAIN_UST;
 291         } else if (fd == handle->kernel_consumer) {
 292                 domain = LTTNG_DOMAIN_KERNEL;
 293         } else {
 294                 ERR("[rotation-thread] Unknown channel rotation pipe fd %d",
 295                                 fd);
 296                 abort();
 297         }
 298
 299         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 300                 ret = lttng_poll_del(&state->events, fd);
 301                 if (ret) {
 302                         ERR("[rotation-thread] Failed to remove consumer "
 303                                         "rotation pipe from poll set");
 304                 }
 305                 goto end;
 306         }
 307
 308         do {
 309                 ret = read(fd, &key, sizeof(key));
 310         } while (ret == -1 && errno == EINTR);
 311         if (ret != sizeof(key)) {
 312                 ERR("[rotation-thread] Failed to read from pipe (fd = %i)",
 313                                 fd);
 314                 ret = -1;
 315                 goto end;
 316         }
 317
 318         DBG("[rotation-thread] Received notification for chan %" PRIu64
 319                         ", domain %d\n", key, domain);
 320
 321         channel_info = lookup_channel_pending(key, domain);
 322         if (!channel_info) {
 323                 ERR("[rotation-thread] Failed to find channel_info (key = %"
 324                                 PRIu64 ")", key);
 325                 ret = -1;
 326                 goto end;
 327         }
 328         rcu_read_lock();
 329         session_lock_list();
 330         session = session_find_by_id(channel_info->session_id);
 331         if (!session) {
 332                 /*
 333                  * The session may have been destroyed before we had a chance to
 334                  * perform this action, return gracefully.
 335                  */
 336                 DBG("[rotation-thread] Session %" PRIu64 " not found",
 337                                 channel_info->session_id);
 338                 ret = 0;
 339                 goto end_unlock_session_list;
 340         }
 341
 342         session_lock(session);
 343         if (--session->nr_chan_rotate_pending == 0) {
 344                 time_t now = time(NULL);
 345
 346                 if (now == (time_t) -1) {
 347                         session->rotation_status = LTTNG_ROTATION_STATUS_ERROR;
 348                         ret = LTTNG_ERR_UNK;
 349                         goto end_unlock_session;
 350                 }
 351
 352                 ret = rename_complete_chunk(session, now);
 353                 if (ret < 0) {
 354                         ERR("Failed to rename completed rotation chunk");
 355                         goto end_unlock_session;
 356                 }
 357                 session->rotate_pending = false;
 358                 session->rotation_status = LTTNG_ROTATION_STATUS_COMPLETED;
 359                 session->last_chunk_start_ts = session->current_chunk_start_ts;
 360                 DBG("Rotation completed for session %s", session->name);
 361         }
 362
 363         ret = 0;
 364
 365 end_unlock_session:
 366         channel_rotation_info_destroy(channel_info);
 367         session_unlock(session);
 368 end_unlock_session_list:
 369         session_unlock_list();
 370         rcu_read_unlock();
 371 end:
 372         return ret;
 373 }
 374
 375 void *thread_rotation(void *data)
 376 {
 377         int ret;
 378         struct rotation_thread_handle *handle = data;
 379         struct rotation_thread_state state;
 380
 381         DBG("[rotation-thread] Started rotation thread");
 382
 383         if (!handle) {
 384                 ERR("[rotation-thread] Invalid thread context provided");
 385                 goto end;
 386         }
 387
 388         rcu_register_thread();
 389         rcu_thread_online();
 390
 391         health_register(health_sessiond, HEALTH_SESSIOND_TYPE_ROTATION);
 392         health_code_update();
 393
 394         ret = init_thread_state(handle, &state);
 395         if (ret) {
 396                 goto end;
 397         }
 398
 399         /* Ready to handle client connections. */
 400         sessiond_notify_ready();
 401
 402         while (true) {
 403                 int fd_count, i;
 404
 405                 health_poll_entry();
 406                 DBG("[rotation-thread] Entering poll wait");
 407                 ret = lttng_poll_wait(&state.events, -1);
 408                 DBG("[rotation-thread] Poll wait returned (%i)", ret);
 409                 health_poll_exit();
 410                 if (ret < 0) {
 411                         /*
 412                          * Restart interrupted system call.
 413                          */
 414                         if (errno == EINTR) {
 415                                 continue;
 416                         }
 417                         ERR("[rotation-thread] Error encountered during lttng_poll_wait (%i)", ret);
 418                         goto error;
 419                 }
 420
 421                 fd_count = ret;
 422                 for (i = 0; i < fd_count; i++) {
 423                         int fd = LTTNG_POLL_GETFD(&state.events, i);
 424                         uint32_t revents = LTTNG_POLL_GETEV(&state.events, i);
 425
 426                         DBG("[rotation-thread] Handling fd (%i) activity (%u)",
 427                                         fd, revents);
 428
 429                         if (fd == handle->thread_quit_pipe) {
 430                                 DBG("[rotation-thread] Quit pipe activity");
 431                                 goto exit;
 432                         } else if (fd == handle->ust32_consumer ||
 433                                         fd == handle->ust64_consumer ||
 434                                         fd == handle->kernel_consumer) {
 435                                 ret = handle_channel_rotation_pipe(fd,
 436                                                 revents, handle, &state);
 437                                 if (ret) {
 438                                         ERR("[rotation-thread] Handle channel rotation pipe");
 439                                         goto error;
 440                                 }
 441                         }
 442                 }
 443         }
 444 exit:
 445 error:
 446         DBG("[rotation-thread] Exit");
 447         fini_thread_state(&state);
 448         health_unregister(health_sessiond);
 449         rcu_thread_offline();
 450         rcu_unregister_thread();
 451 end:
 452         return NULL;
 453 }