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

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