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

   1 /*
   2  * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #define _LGPL_SOURCE
   9 #include <lttng/trigger/trigger.h>
  10 #include <lttng/notification/channel-internal.h>
  11 #include <lttng/notification/notification-internal.h>
  12 #include <lttng/condition/condition-internal.h>
  13 #include <lttng/condition/buffer-usage-internal.h>
  14 #include <common/error.h>
  15 #include <common/config/session-config.h>
  16 #include <common/defaults.h>
  17 #include <common/utils.h>
  18 #include <common/align.h>
  19 #include <common/time.h>
  20 #include <sys/eventfd.h>
  21 #include <sys/stat.h>
  22 #include <time.h>
  23 #include <signal.h>
  24
  25 #include "notification-thread.h"
  26 #include "notification-thread-events.h"
  27 #include "notification-thread-commands.h"
  28 #include "lttng-sessiond.h"
  29 #include "health-sessiond.h"
  30 #include "thread.h"
  31
  32 #include <urcu.h>
  33 #include <urcu/list.h>
  34 #include <urcu/rculfhash.h>
  35
  36 /*
  37  * Destroy the thread data previously created by the init function.
  38  */
  39 void notification_thread_handle_destroy(
  40                 struct notification_thread_handle *handle)
  41 {
  42         int ret;
  43
  44         if (!handle) {
  45                 goto end;
  46         }
  47
  48         assert(cds_list_empty(&handle->cmd_queue.list));
  49         pthread_mutex_destroy(&handle->cmd_queue.lock);
  50         sem_destroy(&handle->ready);
  51
  52         if (handle->cmd_queue.event_pipe) {
  53                 lttng_pipe_destroy(handle->cmd_queue.event_pipe);
  54         }
  55         if (handle->channel_monitoring_pipes.ust32_consumer >= 0) {
  56                 ret = close(handle->channel_monitoring_pipes.ust32_consumer);
  57                 if (ret) {
  58                         PERROR("close 32-bit consumer channel monitoring pipe");
  59                 }
  60         }
  61         if (handle->channel_monitoring_pipes.ust64_consumer >= 0) {
  62                 ret = close(handle->channel_monitoring_pipes.ust64_consumer);
  63                 if (ret) {
  64                         PERROR("close 64-bit consumer channel monitoring pipe");
  65                 }
  66         }
  67         if (handle->channel_monitoring_pipes.kernel_consumer >= 0) {
  68                 ret = close(handle->channel_monitoring_pipes.kernel_consumer);
  69                 if (ret) {
  70                         PERROR("close kernel consumer channel monitoring pipe");
  71                 }
  72         }
  73 end:
  74         free(handle);
  75 }
  76
  77 struct notification_thread_handle *notification_thread_handle_create(
  78                 struct lttng_pipe *ust32_channel_monitor_pipe,
  79                 struct lttng_pipe *ust64_channel_monitor_pipe,
  80                 struct lttng_pipe *kernel_channel_monitor_pipe)
  81 {
  82         int ret;
  83         struct notification_thread_handle *handle;
  84         struct lttng_pipe *event_pipe = NULL;
  85
  86         handle = zmalloc(sizeof(*handle));
  87         if (!handle) {
  88                 goto end;
  89         }
  90
  91         sem_init(&handle->ready, 0, 0);
  92
  93         event_pipe = lttng_pipe_open(FD_CLOEXEC);
  94         if (!event_pipe) {
  95                 ERR("event_pipe creation");
  96                 goto error;
  97         }
  98
  99         handle->cmd_queue.event_pipe = event_pipe;
 100         event_pipe = NULL;
 101
 102         CDS_INIT_LIST_HEAD(&handle->cmd_queue.list);
 103         ret = pthread_mutex_init(&handle->cmd_queue.lock, NULL);
 104         if (ret) {
 105                 goto error;
 106         }
 107
 108         if (ust32_channel_monitor_pipe) {
 109                 handle->channel_monitoring_pipes.ust32_consumer =
 110                                 lttng_pipe_release_readfd(
 111                                         ust32_channel_monitor_pipe);
 112                 if (handle->channel_monitoring_pipes.ust32_consumer < 0) {
 113                         goto error;
 114                 }
 115         } else {
 116                 handle->channel_monitoring_pipes.ust32_consumer = -1;
 117         }
 118         if (ust64_channel_monitor_pipe) {
 119                 handle->channel_monitoring_pipes.ust64_consumer =
 120                                 lttng_pipe_release_readfd(
 121                                         ust64_channel_monitor_pipe);
 122                 if (handle->channel_monitoring_pipes.ust64_consumer < 0) {
 123                         goto error;
 124                 }
 125         } else {
 126                 handle->channel_monitoring_pipes.ust64_consumer = -1;
 127         }
 128         if (kernel_channel_monitor_pipe) {
 129                 handle->channel_monitoring_pipes.kernel_consumer =
 130                                 lttng_pipe_release_readfd(
 131                                         kernel_channel_monitor_pipe);
 132                 if (handle->channel_monitoring_pipes.kernel_consumer < 0) {
 133                         goto error;
 134                 }
 135         } else {
 136                 handle->channel_monitoring_pipes.kernel_consumer = -1;
 137         }
 138 end:
 139         return handle;
 140 error:
 141         lttng_pipe_destroy(event_pipe);
 142         notification_thread_handle_destroy(handle);
 143         return NULL;
 144 }
 145
 146 static
 147 char *get_notification_channel_sock_path(void)
 148 {
 149         int ret;
 150         bool is_root = !getuid();
 151         char *sock_path;
 152
 153         sock_path = zmalloc(LTTNG_PATH_MAX);
 154         if (!sock_path) {
 155                 goto error;
 156         }
 157
 158         if (is_root) {
 159                 ret = snprintf(sock_path, LTTNG_PATH_MAX,
 160                                 DEFAULT_GLOBAL_NOTIFICATION_CHANNEL_UNIX_SOCK);
 161                 if (ret < 0) {
 162                         goto error;
 163                 }
 164         } else {
 165                 const char *home_path = utils_get_home_dir();
 166
 167                 if (!home_path) {
 168                         ERR("Can't get HOME directory for socket creation");
 169                         goto error;
 170                 }
 171
 172                 ret = snprintf(sock_path, LTTNG_PATH_MAX,
 173                                 DEFAULT_HOME_NOTIFICATION_CHANNEL_UNIX_SOCK,
 174                                 home_path);
 175                 if (ret < 0) {
 176                         goto error;
 177                 }
 178         }
 179
 180         return sock_path;
 181 error:
 182         free(sock_path);
 183         return NULL;
 184 }
 185
 186 static
 187 void notification_channel_socket_destroy(int fd)
 188 {
 189         int ret;
 190         char *sock_path = get_notification_channel_sock_path();
 191
 192         DBG("[notification-thread] Destroying notification channel socket");
 193
 194         if (sock_path) {
 195                 ret = unlink(sock_path);
 196                 free(sock_path);
 197                 if (ret < 0) {
 198                         PERROR("unlink notification channel socket");
 199                 }
 200         }
 201
 202         ret = close(fd);
 203         if (ret) {
 204                 PERROR("close notification channel socket");
 205         }
 206 }
 207
 208 static
 209 int notification_channel_socket_create(void)
 210 {
 211         int fd = -1, ret;
 212         char *sock_path = get_notification_channel_sock_path();
 213
 214         DBG("[notification-thread] Creating notification channel UNIX socket at %s",
 215                         sock_path);
 216
 217         ret = lttcomm_create_unix_sock(sock_path);
 218         if (ret < 0) {
 219                 ERR("[notification-thread] Failed to create notification socket");
 220                 goto error;
 221         }
 222         fd = ret;
 223
 224         ret = chmod(sock_path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
 225         if (ret < 0) {
 226                 ERR("Set file permissions failed: %s", sock_path);
 227                 PERROR("chmod notification channel socket");
 228                 goto error;
 229         }
 230
 231         if (getuid() == 0) {
 232                 gid_t gid;
 233
 234                 ret =  utils_get_group_id(config.tracing_group_name.value, true,
 235                                 &gid);
 236                 if (ret) {
 237                         /* Default to root group. */
 238                         gid = 0;
 239                 }
 240
 241                 ret = chown(sock_path, 0, gid);
 242                 if (ret) {
 243                         ERR("Failed to set the notification channel socket's group");
 244                         ret = -1;
 245                         goto error;
 246                 }
 247         }
 248
 249         DBG("[notification-thread] Notification channel UNIX socket created (fd = %i)",
 250                         fd);
 251         free(sock_path);
 252         return fd;
 253 error:
 254         if (fd >= 0 && close(fd) < 0) {
 255                 PERROR("close notification channel socket");
 256         }
 257         free(sock_path);
 258         return ret;
 259 }
 260
 261 static
 262 int init_poll_set(struct lttng_poll_event *poll_set,
 263                 struct notification_thread_handle *handle,
 264                 int notification_channel_socket)
 265 {
 266         int ret;
 267
 268         /*
 269          * Create pollset with size 5:
 270          *      - notification channel socket (listen for new connections),
 271          *      - command queue event fd (internal sessiond commands),
 272          *      - consumerd (32-bit user space) channel monitor pipe,
 273          *      - consumerd (64-bit user space) channel monitor pipe,
 274          *      - consumerd (kernel) channel monitor pipe.
 275          */
 276         ret = lttng_poll_create(poll_set, 5, LTTNG_CLOEXEC);
 277         if (ret < 0) {
 278                 goto end;
 279         }
 280
 281         ret = lttng_poll_add(poll_set, notification_channel_socket,
 282                         LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP);
 283         if (ret < 0) {
 284                 ERR("[notification-thread] Failed to add notification channel socket to pollset");
 285                 goto error;
 286         }
 287         ret = lttng_poll_add(poll_set, lttng_pipe_get_readfd(handle->cmd_queue.event_pipe),
 288                         LPOLLIN | LPOLLERR);
 289         if (ret < 0) {
 290                 ERR("[notification-thread] Failed to add notification command queue event fd to pollset");
 291                 goto error;
 292         }
 293         ret = lttng_poll_add(poll_set,
 294                         handle->channel_monitoring_pipes.ust32_consumer,
 295                         LPOLLIN | LPOLLERR);
 296         if (ret < 0) {
 297                 ERR("[notification-thread] Failed to add ust-32 channel monitoring pipe fd to pollset");
 298                 goto error;
 299         }
 300         ret = lttng_poll_add(poll_set,
 301                         handle->channel_monitoring_pipes.ust64_consumer,
 302                         LPOLLIN | LPOLLERR);
 303         if (ret < 0) {
 304                 ERR("[notification-thread] Failed to add ust-64 channel monitoring pipe fd to pollset");
 305                 goto error;
 306         }
 307         if (handle->channel_monitoring_pipes.kernel_consumer < 0) {
 308                 goto end;
 309         }
 310         ret = lttng_poll_add(poll_set,
 311                         handle->channel_monitoring_pipes.kernel_consumer,
 312                         LPOLLIN | LPOLLERR);
 313         if (ret < 0) {
 314                 ERR("[notification-thread] Failed to add kernel channel monitoring pipe fd to pollset");
 315                 goto error;
 316         }
 317 end:
 318         return ret;
 319 error:
 320         lttng_poll_clean(poll_set);
 321         return ret;
 322 }
 323
 324 static
 325 void fini_thread_state(struct notification_thread_state *state)
 326 {
 327         int ret;
 328
 329         if (state->client_socket_ht) {
 330                 ret = handle_notification_thread_client_disconnect_all(state);
 331                 assert(!ret);
 332                 ret = cds_lfht_destroy(state->client_socket_ht, NULL);
 333                 assert(!ret);
 334         }
 335         if (state->triggers_ht) {
 336                 ret = handle_notification_thread_trigger_unregister_all(state);
 337                 assert(!ret);
 338                 ret = cds_lfht_destroy(state->triggers_ht, NULL);
 339                 assert(!ret);
 340         }
 341         if (state->channel_triggers_ht) {
 342                 ret = cds_lfht_destroy(state->channel_triggers_ht, NULL);
 343                 assert(!ret);
 344         }
 345         if (state->channel_state_ht) {
 346                 ret = cds_lfht_destroy(state->channel_state_ht, NULL);
 347                 assert(!ret);
 348         }
 349         if (state->notification_trigger_clients_ht) {
 350                 ret = cds_lfht_destroy(state->notification_trigger_clients_ht,
 351                                 NULL);
 352                 assert(!ret);
 353         }
 354         if (state->channels_ht) {
 355                 ret = cds_lfht_destroy(state->channels_ht, NULL);
 356                 assert(!ret);
 357         }
 358         if (state->sessions_ht) {
 359                 ret = cds_lfht_destroy(state->sessions_ht, NULL);
 360                 assert(!ret);
 361         }
 362         /*
 363          * Must be destroyed after all channels have been destroyed.
 364          * See comment in struct lttng_session_trigger_list.
 365          */
 366         if (state->session_triggers_ht) {
 367                 ret = cds_lfht_destroy(state->session_triggers_ht, NULL);
 368                 assert(!ret);
 369         }
 370         if (state->notification_channel_socket >= 0) {
 371                 notification_channel_socket_destroy(
 372                                 state->notification_channel_socket);
 373         }
 374         lttng_poll_clean(&state->events);
 375 }
 376
 377 static
 378 void mark_thread_as_ready(struct notification_thread_handle *handle)
 379 {
 380         DBG("Marking notification thread as ready");
 381         sem_post(&handle->ready);
 382 }
 383
 384 static
 385 void wait_until_thread_is_ready(struct notification_thread_handle *handle)
 386 {
 387         DBG("Waiting for notification thread to be ready");
 388         sem_wait(&handle->ready);
 389         DBG("Notification thread is ready");
 390 }
 391
 392 static
 393 int init_thread_state(struct notification_thread_handle *handle,
 394                 struct notification_thread_state *state)
 395 {
 396         int ret;
 397
 398         memset(state, 0, sizeof(*state));
 399         state->notification_channel_socket = -1;
 400         lttng_poll_init(&state->events);
 401
 402         ret = notification_channel_socket_create();
 403         if (ret < 0) {
 404                 goto end;
 405         }
 406         state->notification_channel_socket = ret;
 407
 408         ret = init_poll_set(&state->events, handle,
 409                         state->notification_channel_socket);
 410         if (ret) {
 411                 goto end;
 412         }
 413
 414         DBG("[notification-thread] Listening on notification channel socket");
 415         ret = lttcomm_listen_unix_sock(state->notification_channel_socket);
 416         if (ret < 0) {
 417                 ERR("[notification-thread] Listen failed on notification channel socket");
 418                 goto error;
 419         }
 420
 421         state->client_socket_ht = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
 422                         CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
 423         if (!state->client_socket_ht) {
 424                 goto error;
 425         }
 426
 427         state->channel_triggers_ht = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
 428                         CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
 429         if (!state->channel_triggers_ht) {
 430                 goto error;
 431         }
 432
 433         state->session_triggers_ht = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
 434                         CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
 435         if (!state->session_triggers_ht) {
 436                 goto error;
 437         }
 438
 439         state->channel_state_ht = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
 440                         CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
 441         if (!state->channel_state_ht) {
 442                 goto error;
 443         }
 444
 445         state->notification_trigger_clients_ht = cds_lfht_new(DEFAULT_HT_SIZE,
 446                         1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
 447         if (!state->notification_trigger_clients_ht) {
 448                 goto error;
 449         }
 450
 451         state->channels_ht = cds_lfht_new(DEFAULT_HT_SIZE,
 452                         1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
 453         if (!state->channels_ht) {
 454                 goto error;
 455         }
 456         state->sessions_ht = cds_lfht_new(DEFAULT_HT_SIZE,
 457                         1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
 458         if (!state->sessions_ht) {
 459                 goto error;
 460         }
 461         state->triggers_ht = cds_lfht_new(DEFAULT_HT_SIZE,
 462                         1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
 463         if (!state->triggers_ht) {
 464                 goto error;
 465         }
 466         mark_thread_as_ready(handle);
 467 end:
 468         return 0;
 469 error:
 470         fini_thread_state(state);
 471         return -1;
 472 }
 473
 474 static
 475 int handle_channel_monitoring_pipe(int fd, uint32_t revents,
 476                 struct notification_thread_handle *handle,
 477                 struct notification_thread_state *state)
 478 {
 479         int ret = 0;
 480         enum lttng_domain_type domain;
 481
 482         if (fd == handle->channel_monitoring_pipes.ust32_consumer ||
 483                         fd == handle->channel_monitoring_pipes.ust64_consumer) {
 484                 domain = LTTNG_DOMAIN_UST;
 485         } else if (fd == handle->channel_monitoring_pipes.kernel_consumer) {
 486                 domain = LTTNG_DOMAIN_KERNEL;
 487         } else {
 488                 abort();
 489         }
 490
 491         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 492                 ret = lttng_poll_del(&state->events, fd);
 493                 if (ret) {
 494                         ERR("[notification-thread] Failed to remove consumer monitoring pipe from poll set");
 495                 }
 496                 goto end;
 497         }
 498
 499         ret = handle_notification_thread_channel_sample(
 500                         state, fd, domain);
 501         if (ret) {
 502                 ERR("[notification-thread] Consumer sample handling error occurred");
 503                 ret = -1;
 504                 goto end;
 505         }
 506 end:
 507         return ret;
 508 }
 509
 510 /*
 511  * This thread services notification channel clients and commands received
 512  * from various lttng-sessiond components over a command queue.
 513  */
 514 static
 515 void *thread_notification(void *data)
 516 {
 517         int ret;
 518         struct notification_thread_handle *handle = data;
 519         struct notification_thread_state state;
 520
 521         DBG("[notification-thread] Started notification thread");
 522
 523         health_register(health_sessiond, HEALTH_SESSIOND_TYPE_NOTIFICATION);
 524         rcu_register_thread();
 525         rcu_thread_online();
 526
 527         if (!handle) {
 528                 ERR("[notification-thread] Invalid thread context provided");
 529                 goto end;
 530         }
 531
 532         health_code_update();
 533
 534         ret = init_thread_state(handle, &state);
 535         if (ret) {
 536                 goto end;
 537         }
 538
 539         while (true) {
 540                 int fd_count, i;
 541
 542                 health_poll_entry();
 543                 DBG("[notification-thread] Entering poll wait");
 544                 ret = lttng_poll_wait(&state.events, -1);
 545                 DBG("[notification-thread] Poll wait returned (%i)", ret);
 546                 health_poll_exit();
 547                 if (ret < 0) {
 548                         /*
 549                          * Restart interrupted system call.
 550                          */
 551                         if (errno == EINTR) {
 552                                 continue;
 553                         }
 554                         ERR("[notification-thread] Error encountered during lttng_poll_wait (%i)", ret);
 555                         goto error;
 556                 }
 557
 558                 fd_count = ret;
 559                 for (i = 0; i < fd_count; i++) {
 560                         int fd = LTTNG_POLL_GETFD(&state.events, i);
 561                         uint32_t revents = LTTNG_POLL_GETEV(&state.events, i);
 562
 563                         DBG("[notification-thread] Handling fd (%i) activity (%u)", fd, revents);
 564
 565                         if (fd == state.notification_channel_socket) {
 566                                 if (revents & LPOLLIN) {
 567                                         ret = handle_notification_thread_client_connect(
 568                                                         &state);
 569                                         if (ret < 0) {
 570                                                 goto error;
 571                                         }
 572                                 } else if (revents &
 573                                                 (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 574                                         ERR("[notification-thread] Notification socket poll error");
 575                                         goto error;
 576                                 } else {
 577                                         ERR("[notification-thread] Unexpected poll events %u for notification socket %i", revents, fd);
 578                                         goto error;
 579                                 }
 580                         } else if (fd == lttng_pipe_get_readfd(handle->cmd_queue.event_pipe)) {
 581                                 ret = handle_notification_thread_command(handle,
 582                                                 &state);
 583                                 if (ret < 0) {
 584                                         DBG("[notification-thread] Error encountered while servicing command queue");
 585                                         goto error;
 586                                 } else if (ret > 0) {
 587                                         goto exit;
 588                                 }
 589                         } else if (fd == handle->channel_monitoring_pipes.ust32_consumer ||
 590                                         fd == handle->channel_monitoring_pipes.ust64_consumer ||
 591                                         fd == handle->channel_monitoring_pipes.kernel_consumer) {
 592                                 ret = handle_channel_monitoring_pipe(fd,
 593                                                 revents, handle, &state);
 594                                 if (ret) {
 595                                         goto error;
 596                                 }
 597                         } else {
 598                                 /* Activity on a client's socket. */
 599                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 600                                         /*
 601                                          * It doesn't matter if a command was
 602                                          * pending on the client socket at this
 603                                          * point since it now has no way to
 604                                          * receive the notifications to which
 605                                          * it was subscribing or unsubscribing.
 606                                          */
 607                                         ret = handle_notification_thread_client_disconnect(
 608                                                         fd, &state);
 609                                         if (ret) {
 610                                                 goto error;
 611                                         }
 612                                 } else {
 613                                         if (revents & LPOLLIN) {
 614                                                 ret = handle_notification_thread_client_in(
 615                                                         &state, fd);
 616                                                 if (ret) {
 617                                                         goto error;
 618                                                 }
 619                                         }
 620
 621                                         if (revents & LPOLLOUT) {
 622                                                 ret = handle_notification_thread_client_out(
 623                                                         &state, fd);
 624                                                 if (ret) {
 625                                                         goto error;
 626                                                 }
 627                                         }
 628                                 }
 629                         }
 630                 }
 631         }
 632 exit:
 633 error:
 634         fini_thread_state(&state);
 635 end:
 636         rcu_thread_offline();
 637         rcu_unregister_thread();
 638         health_unregister(health_sessiond);
 639         return NULL;
 640 }
 641
 642 static
 643 bool shutdown_notification_thread(void *thread_data)
 644 {
 645         struct notification_thread_handle *handle = thread_data;
 646
 647         notification_thread_command_quit(handle);
 648         return true;
 649 }
 650
 651 struct lttng_thread *launch_notification_thread(
 652                 struct notification_thread_handle *handle)
 653 {
 654         struct lttng_thread *thread;
 655
 656         thread = lttng_thread_create("Notification",
 657                         thread_notification,
 658                         shutdown_notification_thread,
 659                         NULL,
 660                         handle);
 661         if (!thread) {
 662                 goto error;
 663         }
 664
 665         /*
 666          * Wait for the thread to be marked as "ready" before returning
 667          * as other subsystems depend on the notification subsystem
 668          * (e.g. rotation thread).
 669          */
 670         wait_until_thread_is_ready(handle);
 671         return thread;
 672 error:
 673         return NULL;
 674 }