src/bin/lttng-relayd/live.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _LGPL_SOURCE
  21 #include <getopt.h>
  22 #include <grp.h>
  23 #include <limits.h>
  24 #include <pthread.h>
  25 #include <signal.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <sys/mman.h>
  30 #include <sys/mount.h>
  31 #include <sys/resource.h>
  32 #include <sys/socket.h>
  33 #include <sys/stat.h>
  34 #include <sys/types.h>
  35 #include <sys/wait.h>
  36 #include <inttypes.h>
  37 #include <urcu/futex.h>
  38 #include <urcu/uatomic.h>
  39 #include <urcu/rculist.h>
  40 #include <unistd.h>
  41 #include <fcntl.h>
  42
  43 #include <lttng/lttng.h>
  44 #include <common/common.h>
  45 #include <common/compat/poll.h>
  46 #include <common/compat/socket.h>
  47 #include <common/compat/endian.h>
  48 #include <common/defaults.h>
  49 #include <common/futex.h>
  50 #include <common/index/index.h>
  51 #include <common/sessiond-comm/sessiond-comm.h>
  52 #include <common/sessiond-comm/inet.h>
  53 #include <common/sessiond-comm/relayd.h>
  54 #include <common/uri.h>
  55 #include <common/utils.h>
  56
  57 #include "cmd.h"
  58 #include "live.h"
  59 #include "lttng-relayd.h"
  60 #include "utils.h"
  61 #include "health-relayd.h"
  62 #include "testpoint.h"
  63 #include "viewer-stream.h"
  64 #include "stream.h"
  65 #include "session.h"
  66 #include "ctf-trace.h"
  67 #include "connection.h"
  68 #include "viewer-session.h"
  69
  70 #define SESSION_BUF_DEFAULT_COUNT       16
  71
  72 static struct lttng_uri *live_uri;
  73
  74 /*
  75  * This pipe is used to inform the worker thread that a command is queued and
  76  * ready to be processed.
  77  */
  78 static int live_conn_pipe[2] = { -1, -1 };
  79
  80 /* Shared between threads */
  81 static int live_dispatch_thread_exit;
  82
  83 static pthread_t live_listener_thread;
  84 static pthread_t live_dispatcher_thread;
  85 static pthread_t live_worker_thread;
  86
  87 /*
  88  * Relay command queue.
  89  *
  90  * The live_thread_listener and live_thread_dispatcher communicate with this
  91  * queue.
  92  */
  93 static struct relay_conn_queue viewer_conn_queue;
  94
  95 static uint64_t last_relay_viewer_session_id;
  96 static pthread_mutex_t last_relay_viewer_session_id_lock =
  97                 PTHREAD_MUTEX_INITIALIZER;
  98
  99 /*
 100  * Cleanup the daemon
 101  */
 102 static
 103 void cleanup_relayd_live(void)
 104 {
 105         DBG("Cleaning up");
 106
 107         free(live_uri);
 108 }
 109
 110 /*
 111  * Receive a request buffer using a given socket, destination allocated buffer
 112  * of length size.
 113  *
 114  * Return the size of the received message or else a negative value on error
 115  * with errno being set by recvmsg() syscall.
 116  */
 117 static
 118 ssize_t recv_request(struct lttcomm_sock *sock, void *buf, size_t size)
 119 {
 120         ssize_t ret;
 121
 122         ret = sock->ops->recvmsg(sock, buf, size, 0);
 123         if (ret < 0 || ret != size) {
 124                 if (ret == 0) {
 125                         /* Orderly shutdown. Not necessary to print an error. */
 126                         DBG("Socket %d did an orderly shutdown", sock->fd);
 127                 } else {
 128                         ERR("Relay failed to receive request.");
 129                 }
 130                 ret = -1;
 131         }
 132
 133         return ret;
 134 }
 135
 136 /*
 137  * Send a response buffer using a given socket, source allocated buffer of
 138  * length size.
 139  *
 140  * Return the size of the sent message or else a negative value on error with
 141  * errno being set by sendmsg() syscall.
 142  */
 143 static
 144 ssize_t send_response(struct lttcomm_sock *sock, void *buf, size_t size)
 145 {
 146         ssize_t ret;
 147
 148         ret = sock->ops->sendmsg(sock, buf, size, 0);
 149         if (ret < 0) {
 150                 ERR("Relayd failed to send response.");
 151         }
 152
 153         return ret;
 154 }
 155
 156 /*
 157  * Atomically check if new streams got added in one of the sessions attached
 158  * and reset the flag to 0.
 159  *
 160  * Returns 1 if new streams got added, 0 if nothing changed, a negative value
 161  * on error.
 162  */
 163 static
 164 int check_new_streams(struct relay_connection *conn)
 165 {
 166         struct relay_session *session;
 167         unsigned long current_val;
 168         int ret = 0;
 169
 170         if (!conn->viewer_session) {
 171                 goto end;
 172         }
 173         rcu_read_lock();
 174         cds_list_for_each_entry_rcu(session,
 175                         &conn->viewer_session->session_list,
 176                         viewer_session_node) {
 177                 if (!session_get(session)) {
 178                         continue;
 179                 }
 180                 current_val = uatomic_cmpxchg(&session->new_streams, 1, 0);
 181                 ret = current_val;
 182                 session_put(session);
 183                 if (ret == 1) {
 184                         goto end;
 185                 }
 186         }
 187 end:
 188         rcu_read_unlock();
 189         return ret;
 190 }
 191
 192 /*
 193  * Send viewer streams to the given socket. The ignore_sent_flag indicates if
 194  * this function should ignore the sent flag or not.
 195  *
 196  * Return 0 on success or else a negative value.
 197  */
 198 static
 199 ssize_t send_viewer_streams(struct lttcomm_sock *sock,
 200                 uint64_t session_id, unsigned int ignore_sent_flag)
 201 {
 202         ssize_t ret;
 203         struct lttng_viewer_stream send_stream;
 204         struct lttng_ht_iter iter;
 205         struct relay_viewer_stream *vstream;
 206
 207         rcu_read_lock();
 208
 209         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
 210                         stream_n.node) {
 211                 struct ctf_trace *ctf_trace;
 212
 213                 health_code_update();
 214
 215                 if (!viewer_stream_get(vstream)) {
 216                         continue;
 217                 }
 218
 219                 pthread_mutex_lock(&vstream->stream->lock);
 220                 /* Ignore if not the same session. */
 221                 if (vstream->stream->trace->session->id != session_id ||
 222                                 (!ignore_sent_flag && vstream->sent_flag)) {
 223                         pthread_mutex_unlock(&vstream->stream->lock);
 224                         viewer_stream_put(vstream);
 225                         continue;
 226                 }
 227
 228                 ctf_trace = vstream->stream->trace;
 229                 send_stream.id = htobe64(vstream->stream->stream_handle);
 230                 send_stream.ctf_trace_id = htobe64(ctf_trace->id);
 231                 send_stream.metadata_flag = htobe32(
 232                                 vstream->stream->is_metadata);
 233                 if (lttng_strncpy(send_stream.path_name, vstream->path_name,
 234                                 sizeof(send_stream.path_name))) {
 235                         pthread_mutex_unlock(&vstream->stream->lock);
 236                         viewer_stream_put(vstream);
 237                         ret = -1;       /* Error. */
 238                         goto end_unlock;
 239                 }
 240                 if (lttng_strncpy(send_stream.channel_name,
 241                                 vstream->channel_name,
 242                                 sizeof(send_stream.channel_name))) {
 243                         pthread_mutex_unlock(&vstream->stream->lock);
 244                         viewer_stream_put(vstream);
 245                         ret = -1;       /* Error. */
 246                         goto end_unlock;
 247                 }
 248
 249                 DBG("Sending stream %" PRIu64 " to viewer",
 250                                 vstream->stream->stream_handle);
 251                 vstream->sent_flag = 1;
 252                 pthread_mutex_unlock(&vstream->stream->lock);
 253
 254                 ret = send_response(sock, &send_stream, sizeof(send_stream));
 255                 viewer_stream_put(vstream);
 256                 if (ret < 0) {
 257                         goto end_unlock;
 258                 }
 259         }
 260
 261         ret = 0;
 262
 263 end_unlock:
 264         rcu_read_unlock();
 265         return ret;
 266 }
 267
 268 /*
 269  * Create every viewer stream possible for the given session with the seek
 270  * type. Three counters *can* be return which are in order the total amount of
 271  * viewer stream of the session, the number of unsent stream and the number of
 272  * stream created. Those counters can be NULL and thus will be ignored.
 273  *
 274  * session must be locked to ensure that we see either none or all initial
 275  * streams for a session, but no intermediate state..
 276  *
 277  * Return 0 on success or else a negative value.
 278  */
 279 static int make_viewer_streams(struct relay_session *session,
 280                 struct lttng_trace_chunk *viewer_trace_chunk,
 281                 enum lttng_viewer_seek seek_t,
 282                 uint32_t *nb_total,
 283                 uint32_t *nb_unsent,
 284                 uint32_t *nb_created,
 285                 bool *closed)
 286 {
 287         int ret;
 288         struct lttng_ht_iter iter;
 289         struct ctf_trace *ctf_trace;
 290
 291         assert(session);
 292         ASSERT_LOCKED(session->lock);
 293
 294         if (session->connection_closed) {
 295                 *closed = true;
 296         }
 297
 298         /*
 299          * Create viewer streams for relay streams that are ready to be
 300          * used for a the given session id only.
 301          */
 302         rcu_read_lock();
 303         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 304                         node.node) {
 305                 struct relay_stream *stream;
 306
 307                 health_code_update();
 308
 309                 if (!ctf_trace_get(ctf_trace)) {
 310                         continue;
 311                 }
 312
 313                 cds_list_for_each_entry_rcu(stream, &ctf_trace->stream_list, stream_node) {
 314                         struct relay_viewer_stream *vstream;
 315
 316                         if (!stream_get(stream)) {
 317                                 continue;
 318                         }
 319                         /*
 320                          * stream published is protected by the session lock.
 321                          */
 322                         if (!stream->published) {
 323                                 goto next;
 324                         }
 325                         vstream = viewer_stream_get_by_id(stream->stream_handle);
 326                         if (!vstream) {
 327                                 vstream = viewer_stream_create(stream,
 328                                                 viewer_trace_chunk, seek_t);
 329                                 if (!vstream) {
 330                                         ret = -1;
 331                                         ctf_trace_put(ctf_trace);
 332                                         stream_put(stream);
 333                                         goto error_unlock;
 334                                 }
 335
 336                                 if (nb_created) {
 337                                         /* Update number of created stream counter. */
 338                                         (*nb_created)++;
 339                                 }
 340                                 /*
 341                                  * Ensure a self-reference is preserved even
 342                                  * after we have put our local reference.
 343                                  */
 344                                 if (!viewer_stream_get(vstream)) {
 345                                         ERR("Unable to get self-reference on viewer stream, logic error.");
 346                                         abort();
 347                                 }
 348                         } else {
 349                                 if (!vstream->sent_flag && nb_unsent) {
 350                                         /* Update number of unsent stream counter. */
 351                                         (*nb_unsent)++;
 352                                 }
 353                         }
 354                         /* Update number of total stream counter. */
 355                         if (nb_total) {
 356                                 if (stream->is_metadata) {
 357                                         if (!stream->closed ||
 358                                                         stream->metadata_received > vstream->metadata_sent) {
 359                                                 (*nb_total)++;
 360                                         }
 361                                 } else {
 362                                         if (!stream->closed ||
 363                                                 !(((int64_t) (stream->prev_data_seq - stream->last_net_seq_num)) >= 0)) {
 364
 365                                                 (*nb_total)++;
 366                                         }
 367                                 }
 368                         }
 369                         /* Put local reference. */
 370                         viewer_stream_put(vstream);
 371                 next:
 372                         stream_put(stream);
 373                 }
 374                 ctf_trace_put(ctf_trace);
 375         }
 376
 377         ret = 0;
 378
 379 error_unlock:
 380         rcu_read_unlock();
 381         return ret;
 382 }
 383
 384 int relayd_live_stop(void)
 385 {
 386         /* Stop dispatch thread */
 387         CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
 388         futex_nto1_wake(&viewer_conn_queue.futex);
 389         return 0;
 390 }
 391
 392 /*
 393  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 394  */
 395 static
 396 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 397 {
 398         int ret;
 399
 400         if (events == NULL || size == 0) {
 401                 ret = -1;
 402                 goto error;
 403         }
 404
 405         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 406         if (ret < 0) {
 407                 goto error;
 408         }
 409
 410         /* Add quit pipe */
 411         ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
 412         if (ret < 0) {
 413                 goto error;
 414         }
 415
 416         return 0;
 417
 418 error:
 419         return ret;
 420 }
 421
 422 /*
 423  * Check if the thread quit pipe was triggered.
 424  *
 425  * Return 1 if it was triggered else 0;
 426  */
 427 static
 428 int check_thread_quit_pipe(int fd, uint32_t events)
 429 {
 430         if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
 431                 return 1;
 432         }
 433
 434         return 0;
 435 }
 436
 437 /*
 438  * Create and init socket from uri.
 439  */
 440 static
 441 struct lttcomm_sock *init_socket(struct lttng_uri *uri)
 442 {
 443         int ret;
 444         struct lttcomm_sock *sock = NULL;
 445
 446         sock = lttcomm_alloc_sock_from_uri(uri);
 447         if (sock == NULL) {
 448                 ERR("Allocating socket");
 449                 goto error;
 450         }
 451
 452         ret = lttcomm_create_sock(sock);
 453         if (ret < 0) {
 454                 goto error;
 455         }
 456         DBG("Listening on sock %d for lttng-live", sock->fd);
 457
 458         ret = sock->ops->bind(sock);
 459         if (ret < 0) {
 460                 PERROR("Failed to bind lttng-live socket");
 461                 goto error;
 462         }
 463
 464         ret = sock->ops->listen(sock, -1);
 465         if (ret < 0) {
 466                 goto error;
 467
 468         }
 469
 470         return sock;
 471
 472 error:
 473         if (sock) {
 474                 lttcomm_destroy_sock(sock);
 475         }
 476         return NULL;
 477 }
 478
 479 /*
 480  * This thread manages the listening for new connections on the network
 481  */
 482 static
 483 void *thread_listener(void *data)
 484 {
 485         int i, ret, pollfd, err = -1;
 486         uint32_t revents, nb_fd;
 487         struct lttng_poll_event events;
 488         struct lttcomm_sock *live_control_sock;
 489
 490         DBG("[thread] Relay live listener started");
 491
 492         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_LISTENER);
 493
 494         health_code_update();
 495
 496         live_control_sock = init_socket(live_uri);
 497         if (!live_control_sock) {
 498                 goto error_sock_control;
 499         }
 500
 501         /* Pass 2 as size here for the thread quit pipe and control sockets. */
 502         ret = create_thread_poll_set(&events, 2);
 503         if (ret < 0) {
 504                 goto error_create_poll;
 505         }
 506
 507         /* Add the control socket */
 508         ret = lttng_poll_add(&events, live_control_sock->fd, LPOLLIN | LPOLLRDHUP);
 509         if (ret < 0) {
 510                 goto error_poll_add;
 511         }
 512
 513         lttng_relay_notify_ready();
 514
 515         if (testpoint(relayd_thread_live_listener)) {
 516                 goto error_testpoint;
 517         }
 518
 519         while (1) {
 520                 health_code_update();
 521
 522                 DBG("Listener accepting live viewers connections");
 523
 524 restart:
 525                 health_poll_entry();
 526                 ret = lttng_poll_wait(&events, -1);
 527                 health_poll_exit();
 528                 if (ret < 0) {
 529                         /*
 530                          * Restart interrupted system call.
 531                          */
 532                         if (errno == EINTR) {
 533                                 goto restart;
 534                         }
 535                         goto error;
 536                 }
 537                 nb_fd = ret;
 538
 539                 DBG("Relay new viewer connection received");
 540                 for (i = 0; i < nb_fd; i++) {
 541                         health_code_update();
 542
 543                         /* Fetch once the poll data */
 544                         revents = LTTNG_POLL_GETEV(&events, i);
 545                         pollfd = LTTNG_POLL_GETFD(&events, i);
 546
 547                         /* Thread quit pipe has been closed. Killing thread. */
 548                         ret = check_thread_quit_pipe(pollfd, revents);
 549                         if (ret) {
 550                                 err = 0;
 551                                 goto exit;
 552                         }
 553
 554                         if (revents & LPOLLIN) {
 555                                 /*
 556                                  * A new connection is requested, therefore a
 557                                  * viewer connection is allocated in this
 558                                  * thread, enqueued to a global queue and
 559                                  * dequeued (and freed) in the worker thread.
 560                                  */
 561                                 int val = 1;
 562                                 struct relay_connection *new_conn;
 563                                 struct lttcomm_sock *newsock;
 564
 565                                 newsock = live_control_sock->ops->accept(live_control_sock);
 566                                 if (!newsock) {
 567                                         PERROR("accepting control sock");
 568                                         goto error;
 569                                 }
 570                                 DBG("Relay viewer connection accepted socket %d", newsock->fd);
 571
 572                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR, &val,
 573                                                 sizeof(val));
 574                                 if (ret < 0) {
 575                                         PERROR("setsockopt inet");
 576                                         lttcomm_destroy_sock(newsock);
 577                                         goto error;
 578                                 }
 579                                 new_conn = connection_create(newsock, RELAY_CONNECTION_UNKNOWN);
 580                                 if (!new_conn) {
 581                                         lttcomm_destroy_sock(newsock);
 582                                         goto error;
 583                                 }
 584                                 /* Ownership assumed by the connection. */
 585                                 newsock = NULL;
 586
 587                                 /* Enqueue request for the dispatcher thread. */
 588                                 cds_wfcq_enqueue(&viewer_conn_queue.head, &viewer_conn_queue.tail,
 589                                                  &new_conn->qnode);
 590
 591                                 /*
 592                                  * Wake the dispatch queue futex.
 593                                  * Implicit memory barrier with the
 594                                  * exchange in cds_wfcq_enqueue.
 595                                  */
 596                                 futex_nto1_wake(&viewer_conn_queue.futex);
 597                         } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 598                                 ERR("socket poll error");
 599                                 goto error;
 600                         } else {
 601                                 ERR("Unexpected poll events %u for sock %d", revents, pollfd);
 602                                 goto error;
 603                         }
 604                 }
 605         }
 606
 607 exit:
 608 error:
 609 error_poll_add:
 610 error_testpoint:
 611         lttng_poll_clean(&events);
 612 error_create_poll:
 613         if (live_control_sock->fd >= 0) {
 614                 ret = live_control_sock->ops->close(live_control_sock);
 615                 if (ret) {
 616                         PERROR("close");
 617                 }
 618         }
 619         lttcomm_destroy_sock(live_control_sock);
 620 error_sock_control:
 621         if (err) {
 622                 health_error();
 623                 DBG("Live viewer listener thread exited with error");
 624         }
 625         health_unregister(health_relayd);
 626         DBG("Live viewer listener thread cleanup complete");
 627         if (lttng_relay_stop_threads()) {
 628                 ERR("Error stopping threads");
 629         }
 630         return NULL;
 631 }
 632
 633 /*
 634  * This thread manages the dispatching of the requests to worker threads
 635  */
 636 static
 637 void *thread_dispatcher(void *data)
 638 {
 639         int err = -1;
 640         ssize_t ret;
 641         struct cds_wfcq_node *node;
 642         struct relay_connection *conn = NULL;
 643
 644         DBG("[thread] Live viewer relay dispatcher started");
 645
 646         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 647
 648         if (testpoint(relayd_thread_live_dispatcher)) {
 649                 goto error_testpoint;
 650         }
 651
 652         health_code_update();
 653
 654         for (;;) {
 655                 health_code_update();
 656
 657                 /* Atomically prepare the queue futex */
 658                 futex_nto1_prepare(&viewer_conn_queue.futex);
 659
 660                 if (CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 661                         break;
 662                 }
 663
 664                 do {
 665                         health_code_update();
 666
 667                         /* Dequeue commands */
 668                         node = cds_wfcq_dequeue_blocking(&viewer_conn_queue.head,
 669                                                          &viewer_conn_queue.tail);
 670                         if (node == NULL) {
 671                                 DBG("Woken up but nothing in the live-viewer "
 672                                                 "relay command queue");
 673                                 /* Continue thread execution */
 674                                 break;
 675                         }
 676                         conn = caa_container_of(node, struct relay_connection, qnode);
 677                         DBG("Dispatching viewer request waiting on sock %d",
 678                                         conn->sock->fd);
 679
 680                         /*
 681                          * Inform worker thread of the new request. This
 682                          * call is blocking so we can be assured that
 683                          * the data will be read at some point in time
 684                          * or wait to the end of the world :)
 685                          */
 686                         ret = lttng_write(live_conn_pipe[1], &conn, sizeof(conn));
 687                         if (ret < 0) {
 688                                 PERROR("write conn pipe");
 689                                 connection_put(conn);
 690                                 goto error;
 691                         }
 692                 } while (node != NULL);
 693
 694                 /* Futex wait on queue. Blocking call on futex() */
 695                 health_poll_entry();
 696                 futex_nto1_wait(&viewer_conn_queue.futex);
 697                 health_poll_exit();
 698         }
 699
 700         /* Normal exit, no error */
 701         err = 0;
 702
 703 error:
 704 error_testpoint:
 705         if (err) {
 706                 health_error();
 707                 ERR("Health error occurred in %s", __func__);
 708         }
 709         health_unregister(health_relayd);
 710         DBG("Live viewer dispatch thread dying");
 711         if (lttng_relay_stop_threads()) {
 712                 ERR("Error stopping threads");
 713         }
 714         return NULL;
 715 }
 716
 717 /*
 718  * Establish connection with the viewer and check the versions.
 719  *
 720  * Return 0 on success or else negative value.
 721  */
 722 static
 723 int viewer_connect(struct relay_connection *conn)
 724 {
 725         int ret;
 726         struct lttng_viewer_connect reply, msg;
 727
 728         conn->version_check_done = 1;
 729
 730         health_code_update();
 731
 732         DBG("Viewer is establishing a connection to the relayd.");
 733
 734         ret = recv_request(conn->sock, &msg, sizeof(msg));
 735         if (ret < 0) {
 736                 goto end;
 737         }
 738
 739         health_code_update();
 740
 741         memset(&reply, 0, sizeof(reply));
 742         reply.major = RELAYD_VERSION_COMM_MAJOR;
 743         reply.minor = RELAYD_VERSION_COMM_MINOR;
 744
 745         /* Major versions must be the same */
 746         if (reply.major != be32toh(msg.major)) {
 747                 DBG("Incompatible major versions ([relayd] %u vs [client] %u)",
 748                                 reply.major, be32toh(msg.major));
 749                 ret = -1;
 750                 goto end;
 751         }
 752
 753         conn->major = reply.major;
 754         /* We adapt to the lowest compatible version */
 755         if (reply.minor <= be32toh(msg.minor)) {
 756                 conn->minor = reply.minor;
 757         } else {
 758                 conn->minor = be32toh(msg.minor);
 759         }
 760
 761         if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_COMMAND) {
 762                 conn->type = RELAY_VIEWER_COMMAND;
 763         } else if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_NOTIFICATION) {
 764                 conn->type = RELAY_VIEWER_NOTIFICATION;
 765         } else {
 766                 ERR("Unknown connection type : %u", be32toh(msg.type));
 767                 ret = -1;
 768                 goto end;
 769         }
 770
 771         reply.major = htobe32(reply.major);
 772         reply.minor = htobe32(reply.minor);
 773         if (conn->type == RELAY_VIEWER_COMMAND) {
 774                 /*
 775                  * Increment outside of htobe64 macro, because the argument can
 776                  * be used more than once within the macro, and thus the
 777                  * operation may be undefined.
 778                  */
 779                 pthread_mutex_lock(&last_relay_viewer_session_id_lock);
 780                 last_relay_viewer_session_id++;
 781                 pthread_mutex_unlock(&last_relay_viewer_session_id_lock);
 782                 reply.viewer_session_id = htobe64(last_relay_viewer_session_id);
 783         }
 784
 785         health_code_update();
 786
 787         ret = send_response(conn->sock, &reply, sizeof(reply));
 788         if (ret < 0) {
 789                 goto end;
 790         }
 791
 792         health_code_update();
 793
 794         DBG("Version check done using protocol %u.%u", conn->major, conn->minor);
 795         ret = 0;
 796
 797 end:
 798         return ret;
 799 }
 800
 801 /*
 802  * Send the viewer the list of current sessions.
 803  * We need to create a copy of the hash table content because otherwise
 804  * we cannot assume the number of entries stays the same between getting
 805  * the number of HT elements and iteration over the HT.
 806  *
 807  * Return 0 on success or else a negative value.
 808  */
 809 static
 810 int viewer_list_sessions(struct relay_connection *conn)
 811 {
 812         int ret = 0;
 813         struct lttng_viewer_list_sessions session_list;
 814         struct lttng_ht_iter iter;
 815         struct relay_session *session;
 816         struct lttng_viewer_session *send_session_buf = NULL;
 817         uint32_t buf_count = SESSION_BUF_DEFAULT_COUNT;
 818         uint32_t count = 0;
 819
 820         DBG("List sessions received");
 821
 822         send_session_buf = zmalloc(SESSION_BUF_DEFAULT_COUNT * sizeof(*send_session_buf));
 823         if (!send_session_buf) {
 824                 return -1;
 825         }
 826
 827         rcu_read_lock();
 828         cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
 829                         session_n.node) {
 830                 struct lttng_viewer_session *send_session;
 831
 832                 health_code_update();
 833
 834                 if (session->connection_closed) {
 835                         /* Skip closed session */
 836                         continue;
 837                 }
 838
 839                 if (count >= buf_count) {
 840                         struct lttng_viewer_session *newbuf;
 841                         uint32_t new_buf_count = buf_count << 1;
 842
 843                         newbuf = realloc(send_session_buf,
 844                                 new_buf_count * sizeof(*send_session_buf));
 845                         if (!newbuf) {
 846                                 ret = -1;
 847                                 break;
 848                         }
 849                         send_session_buf = newbuf;
 850                         buf_count = new_buf_count;
 851                 }
 852                 send_session = &send_session_buf[count];
 853                 if (lttng_strncpy(send_session->session_name,
 854                                 session->session_name,
 855                                 sizeof(send_session->session_name))) {
 856                         ret = -1;
 857                         break;
 858                 }
 859                 if (lttng_strncpy(send_session->hostname, session->hostname,
 860                                 sizeof(send_session->hostname))) {
 861                         ret = -1;
 862                         break;
 863                 }
 864                 send_session->id = htobe64(session->id);
 865                 send_session->live_timer = htobe32(session->live_timer);
 866                 if (session->viewer_attached) {
 867                         send_session->clients = htobe32(1);
 868                 } else {
 869                         send_session->clients = htobe32(0);
 870                 }
 871                 send_session->streams = htobe32(session->stream_count);
 872                 count++;
 873         }
 874         rcu_read_unlock();
 875         if (ret < 0) {
 876                 goto end_free;
 877         }
 878
 879         session_list.sessions_count = htobe32(count);
 880
 881         health_code_update();
 882
 883         ret = send_response(conn->sock, &session_list, sizeof(session_list));
 884         if (ret < 0) {
 885                 goto end_free;
 886         }
 887
 888         health_code_update();
 889
 890         ret = send_response(conn->sock, send_session_buf,
 891                         count * sizeof(*send_session_buf));
 892         if (ret < 0) {
 893                 goto end_free;
 894         }
 895         health_code_update();
 896
 897         ret = 0;
 898 end_free:
 899         free(send_session_buf);
 900         return ret;
 901 }
 902
 903 /*
 904  * Send the viewer the list of current streams.
 905  */
 906 static
 907 int viewer_get_new_streams(struct relay_connection *conn)
 908 {
 909         int ret, send_streams = 0;
 910         uint32_t nb_created = 0, nb_unsent = 0, nb_streams = 0, nb_total = 0;
 911         struct lttng_viewer_new_streams_request request;
 912         struct lttng_viewer_new_streams_response response;
 913         struct relay_session *session = NULL;
 914         uint64_t session_id;
 915         bool closed = false;
 916
 917         assert(conn);
 918
 919         DBG("Get new streams received");
 920
 921         health_code_update();
 922
 923         /* Receive the request from the connected client. */
 924         ret = recv_request(conn->sock, &request, sizeof(request));
 925         if (ret < 0) {
 926                 goto error;
 927         }
 928         session_id = be64toh(request.session_id);
 929
 930         health_code_update();
 931
 932         memset(&response, 0, sizeof(response));
 933
 934         session = session_get_by_id(session_id);
 935         if (!session) {
 936                 DBG("Relay session %" PRIu64 " not found", session_id);
 937                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 938                 goto send_reply;
 939         }
 940
 941         if (!viewer_session_is_attached(conn->viewer_session, session)) {
 942                 send_streams = 0;
 943                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 944                 goto send_reply;
 945         }
 946
 947         send_streams = 1;
 948         response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 949
 950         pthread_mutex_lock(&session->lock);
 951         if (!conn->viewer_session->current_trace_chunk &&
 952                         session->current_trace_chunk) {
 953                 ret = viewer_session_set_trace_chunk(conn->viewer_session,
 954                                 session->current_trace_chunk);
 955                 if (ret) {
 956                         goto error_unlock_session;
 957                 }
 958         }
 959         ret = make_viewer_streams(session,
 960                         conn->viewer_session->current_trace_chunk,
 961                         LTTNG_VIEWER_SEEK_LAST, &nb_total, &nb_unsent,
 962                         &nb_created, &closed);
 963         if (ret < 0) {
 964                 goto error_unlock_session;
 965         }
 966         pthread_mutex_unlock(&session->lock);
 967
 968         /* Only send back the newly created streams with the unsent ones. */
 969         nb_streams = nb_created + nb_unsent;
 970         response.streams_count = htobe32(nb_streams);
 971
 972         /*
 973          * If the session is closed, HUP when there are no more streams
 974          * with data.
 975          */
 976         if (closed && nb_total == 0) {
 977                 send_streams = 0;
 978                 response.streams_count = 0;
 979                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
 980                 goto send_reply;
 981         }
 982
 983 send_reply:
 984         health_code_update();
 985         ret = send_response(conn->sock, &response, sizeof(response));
 986         if (ret < 0) {
 987                 goto end_put_session;
 988         }
 989         health_code_update();
 990
 991         /*
 992          * Unknown or empty session, just return gracefully, the viewer
 993          * knows what is happening.
 994          */
 995         if (!send_streams || !nb_streams) {
 996                 ret = 0;
 997                 goto end_put_session;
 998         }
 999
1000         /*
1001          * Send stream and *DON'T* ignore the sent flag so every viewer
1002          * streams that were not sent from that point will be sent to
1003          * the viewer.
1004          */
1005         ret = send_viewer_streams(conn->sock, session_id, 0);
1006         if (ret < 0) {
1007                 goto end_put_session;
1008         }
1009
1010 end_put_session:
1011         if (session) {
1012                 session_put(session);
1013         }
1014 error:
1015         return ret;
1016 error_unlock_session:
1017         pthread_mutex_unlock(&session->lock);
1018         session_put(session);
1019         return ret;
1020 }
1021
1022 /*
1023  * Send the viewer the list of current sessions.
1024  */
1025 static
1026 int viewer_attach_session(struct relay_connection *conn)
1027 {
1028         int send_streams = 0;
1029         ssize_t ret;
1030         uint32_t nb_streams = 0;
1031         enum lttng_viewer_seek seek_type;
1032         struct lttng_viewer_attach_session_request request;
1033         struct lttng_viewer_attach_session_response response;
1034         struct relay_session *session = NULL;
1035         bool closed = false;
1036         uint64_t session_id;
1037
1038         assert(conn);
1039
1040         health_code_update();
1041
1042         /* Receive the request from the connected client. */
1043         ret = recv_request(conn->sock, &request, sizeof(request));
1044         if (ret < 0) {
1045                 goto error;
1046         }
1047
1048         session_id = be64toh(request.session_id);
1049         health_code_update();
1050
1051         memset(&response, 0, sizeof(response));
1052
1053         if (!conn->viewer_session) {
1054                 DBG("Client trying to attach before creating a live viewer session");
1055                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NO_SESSION);
1056                 goto send_reply;
1057         }
1058
1059         session = session_get_by_id(session_id);
1060         if (!session) {
1061                 DBG("Relay session %" PRIu64 " not found", session_id);
1062                 response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
1063                 goto send_reply;
1064         }
1065         DBG("Attach session ID %" PRIu64 " received", session_id);
1066
1067         pthread_mutex_lock(&session->lock);
1068         if (session->live_timer == 0) {
1069                 DBG("Not live session");
1070                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NOT_LIVE);
1071                 goto send_reply;
1072         }
1073
1074         send_streams = 1;
1075         ret = viewer_session_attach(conn->viewer_session, session);
1076         if (ret) {
1077                 DBG("Already a viewer attached");
1078                 response.status = htobe32(LTTNG_VIEWER_ATTACH_ALREADY);
1079                 goto send_reply;
1080         }
1081
1082         switch (be32toh(request.seek)) {
1083         case LTTNG_VIEWER_SEEK_BEGINNING:
1084         case LTTNG_VIEWER_SEEK_LAST:
1085                 response.status = htobe32(LTTNG_VIEWER_ATTACH_OK);
1086                 seek_type = be32toh(request.seek);
1087                 break;
1088         default:
1089                 ERR("Wrong seek parameter");
1090                 response.status = htobe32(LTTNG_VIEWER_ATTACH_SEEK_ERR);
1091                 send_streams = 0;
1092                 goto send_reply;
1093         }
1094
1095         if (!conn->viewer_session->current_trace_chunk &&
1096                         session->current_trace_chunk) {
1097                 ret = viewer_session_set_trace_chunk(conn->viewer_session,
1098                                 session->current_trace_chunk);
1099                 if (ret) {
1100                         goto end_put_session;
1101                 }
1102         }
1103         ret = make_viewer_streams(session,
1104                         conn->viewer_session->current_trace_chunk, seek_type,
1105                         &nb_streams, NULL, NULL, &closed);
1106         if (ret < 0) {
1107                 goto end_put_session;
1108         }
1109         pthread_mutex_unlock(&session->lock);
1110         session_put(session);
1111         session = NULL;
1112
1113         response.streams_count = htobe32(nb_streams);
1114         /*
1115          * If the session is closed when the viewer is attaching, it
1116          * means some of the streams may have been concurrently removed,
1117          * so we don't allow the viewer to attach, even if there are
1118          * streams available.
1119          */
1120         if (closed) {
1121                 send_streams = 0;
1122                 response.streams_count = 0;
1123                 response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
1124                 goto send_reply;
1125         }
1126
1127 send_reply:
1128         health_code_update();
1129         ret = send_response(conn->sock, &response, sizeof(response));
1130         if (ret < 0) {
1131                 goto end_put_session;
1132         }
1133         health_code_update();
1134
1135         /*
1136          * Unknown or empty session, just return gracefully, the viewer
1137          * knows what is happening.
1138          */
1139         if (!send_streams || !nb_streams) {
1140                 ret = 0;
1141                 goto end_put_session;
1142         }
1143
1144         /* Send stream and ignore the sent flag. */
1145         ret = send_viewer_streams(conn->sock, session_id, 1);
1146         if (ret < 0) {
1147                 goto end_put_session;
1148         }
1149
1150 end_put_session:
1151         if (session) {
1152                 pthread_mutex_unlock(&session->lock);
1153                 session_put(session);
1154         }
1155 error:
1156         return ret;
1157 }
1158
1159 /*
1160  * Open the index file if needed for the given vstream.
1161  *
1162  * If an index file is successfully opened, the vstream will set it as its
1163  * current index file.
1164  *
1165  * Return 0 on success, a negative value on error (-ENOENT if not ready yet).
1166  *
1167  * Called with rstream lock held.
1168  */
1169 static int try_open_index(struct relay_viewer_stream *vstream,
1170                 struct relay_stream *rstream)
1171 {
1172         int ret = 0;
1173         const uint32_t connection_major = rstream->trace->session->major;
1174         const uint32_t connection_minor = rstream->trace->session->minor;
1175
1176         if (vstream->index_file) {
1177                 goto end;
1178         }
1179
1180         /*
1181          * First time, we open the index file and at least one index is ready.
1182          */
1183         if (rstream->index_received_seqcount == 0) {
1184                 ret = -ENOENT;
1185                 goto end;
1186         }
1187         vstream->index_file = lttng_index_file_create_from_trace_chunk_read_only(
1188                         vstream->stream_file.trace_chunk, rstream->path_name,
1189                         rstream->channel_name, rstream->tracefile_size,
1190                         vstream->current_tracefile_id,
1191                         lttng_to_index_major(connection_major, connection_minor),
1192                         lttng_to_index_minor(connection_major, connection_minor));
1193         if (!vstream->index_file) {
1194                 ret = -1;
1195         }
1196
1197 end:
1198         return ret;
1199 }
1200
1201 /*
1202  * Check the status of the index for the given stream. This function
1203  * updates the index structure if needed and can put (close) the vstream
1204  * in the HUP situation.
1205  *
1206  * Return 0 means that we can proceed with the index. A value of 1 means
1207  * that the index has been updated and is ready to be sent to the
1208  * client. A negative value indicates an error that can't be handled.
1209  *
1210  * Called with rstream lock held.
1211  */
1212 static int check_index_status(struct relay_viewer_stream *vstream,
1213                 struct relay_stream *rstream, struct ctf_trace *trace,
1214                 struct lttng_viewer_index *index)
1215 {
1216         int ret;
1217
1218         if ((trace->session->connection_closed || rstream->closed)
1219                         && rstream->index_received_seqcount
1220                                 == vstream->index_sent_seqcount) {
1221                 /*
1222                  * Last index sent and session connection or relay
1223                  * stream are closed.
1224                  */
1225                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1226                 goto hup;
1227         } else if (rstream->beacon_ts_end != -1ULL &&
1228                         rstream->index_received_seqcount
1229                                 == vstream->index_sent_seqcount) {
1230                 /*
1231                  * We've received a synchronization beacon and the last index
1232                  * available has been sent, the index for now is inactive.
1233                  *
1234                  * In this case, we have received a beacon which allows us to
1235                  * inform the client of a time interval during which we can
1236                  * guarantee that there are no events to read (and never will
1237                  * be).
1238                  */
1239                 index->status = htobe32(LTTNG_VIEWER_INDEX_INACTIVE);
1240                 index->timestamp_end = htobe64(rstream->beacon_ts_end);
1241                 index->stream_id = htobe64(rstream->ctf_stream_id);
1242                 goto index_ready;
1243         } else if (rstream->index_received_seqcount
1244                         == vstream->index_sent_seqcount) {
1245                 /*
1246                  * This checks whether received == sent seqcount. In
1247                  * this case, we have not received a beacon. Therefore,
1248                  * we can only ask the client to retry later.
1249                  */
1250                 index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1251                 goto index_ready;
1252         } else if (!tracefile_array_seq_in_file(rstream->tfa,
1253                         vstream->current_tracefile_id,
1254                         vstream->index_sent_seqcount)) {
1255                 /*
1256                  * The next index we want to send cannot be read either
1257                  * because we need to perform a rotation, or due to
1258                  * the producer having overwritten its trace file.
1259                  */
1260                 DBG("Viewer stream %" PRIu64 " rotation",
1261                                 vstream->stream->stream_handle);
1262                 ret = viewer_stream_rotate(vstream);
1263                 if (ret < 0) {
1264                         goto end;
1265                 } else if (ret == 1) {
1266                         /* EOF across entire stream. */
1267                         index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1268                         goto hup;
1269                 }
1270                 /*
1271                  * If we have been pushed due to overwrite, it
1272                  * necessarily means there is data that can be read in
1273                  * the stream. If we rotated because we reached the end
1274                  * of a tracefile, it means the following tracefile
1275                  * needs to contain at least one index, else we would
1276                  * have already returned LTTNG_VIEWER_INDEX_RETRY to the
1277                  * viewer. The updated index_sent_seqcount needs to
1278                  * point to a readable index entry now.
1279                  *
1280                  * In the case where we "rotate" on a single file, we
1281                  * can end up in a case where the requested index is
1282                  * still unavailable.
1283                  */
1284                 if (rstream->tracefile_count == 1 &&
1285                                 !tracefile_array_seq_in_file(
1286                                         rstream->tfa,
1287                                         vstream->current_tracefile_id,
1288                                         vstream->index_sent_seqcount)) {
1289                         index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1290                         goto index_ready;
1291                 }
1292                 assert(tracefile_array_seq_in_file(rstream->tfa,
1293                                 vstream->current_tracefile_id,
1294                                 vstream->index_sent_seqcount));
1295         }
1296         /* ret == 0 means successful so we continue. */
1297         ret = 0;
1298 end:
1299         return ret;
1300
1301 hup:
1302         viewer_stream_put(vstream);
1303 index_ready:
1304         return 1;
1305 }
1306
1307 /*
1308  * Send the next index for a stream.
1309  *
1310  * Return 0 on success or else a negative value.
1311  */
1312 static
1313 int viewer_get_next_index(struct relay_connection *conn)
1314 {
1315         int ret;
1316         struct lttng_viewer_get_next_index request_index;
1317         struct lttng_viewer_index viewer_index;
1318         struct ctf_packet_index packet_index;
1319         struct relay_viewer_stream *vstream = NULL;
1320         struct relay_stream *rstream = NULL;
1321         struct ctf_trace *ctf_trace = NULL;
1322         struct relay_viewer_stream *metadata_viewer_stream = NULL;
1323
1324         assert(conn);
1325
1326         DBG("Viewer get next index");
1327
1328         memset(&viewer_index, 0, sizeof(viewer_index));
1329         health_code_update();
1330
1331         ret = recv_request(conn->sock, &request_index, sizeof(request_index));
1332         if (ret < 0) {
1333                 goto end;
1334         }
1335         health_code_update();
1336
1337         vstream = viewer_stream_get_by_id(be64toh(request_index.stream_id));
1338         if (!vstream) {
1339                 DBG("Client requested index of unknown stream id %" PRIu64,
1340                                 (uint64_t) be64toh(request_index.stream_id));
1341                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1342                 goto send_reply;
1343         }
1344
1345         /* Use back. ref. Protected by refcounts. */
1346         rstream = vstream->stream;
1347         ctf_trace = rstream->trace;
1348
1349         /* metadata_viewer_stream may be NULL. */
1350         metadata_viewer_stream =
1351                         ctf_trace_get_viewer_metadata_stream(ctf_trace);
1352
1353         pthread_mutex_lock(&rstream->lock);
1354
1355         /*
1356          * The viewer should not ask for index on metadata stream.
1357          */
1358         if (rstream->is_metadata) {
1359                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1360                 goto send_reply;
1361         }
1362
1363         /* Try to open an index if one is needed for that stream. */
1364         ret = try_open_index(vstream, rstream);
1365         if (ret < 0) {
1366                 if (ret == -ENOENT) {
1367                         /*
1368                          * The index is created only when the first data
1369                          * packet arrives, it might not be ready at the
1370                          * beginning of the session
1371                          */
1372                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1373                 } else {
1374                         /* Unhandled error. */
1375                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1376                 }
1377                 goto send_reply;
1378         }
1379
1380         ret = check_index_status(vstream, rstream, ctf_trace, &viewer_index);
1381         if (ret < 0) {
1382                 goto error_put;
1383         } else if (ret == 1) {
1384                 /*
1385                  * We have no index to send and check_index_status has populated
1386                  * viewer_index's status.
1387                  */
1388                 goto send_reply;
1389         }
1390         /* At this point, ret is 0 thus we will be able to read the index. */
1391         assert(!ret);
1392
1393         /*
1394          * vstream->stream_fd may be NULL if it has been closed by
1395          * tracefile rotation, or if we are at the beginning of the
1396          * stream. We open the data stream file here to protect against
1397          * overwrite caused by tracefile rotation (in association with
1398          * unlink performed before overwrite).
1399          */
1400         if (!vstream->stream_file.fd) {
1401                 int fd;
1402                 char file_path[LTTNG_PATH_MAX];
1403                 enum lttng_trace_chunk_status status;
1404
1405                 ret = utils_stream_file_path(rstream->path_name,
1406                                 rstream->channel_name, rstream->tracefile_size,
1407                                 vstream->current_tracefile_id, NULL, file_path,
1408                                 sizeof(file_path));
1409                 if (ret < 0) {
1410                         goto error_put;
1411                 }
1412
1413                 status = lttng_trace_chunk_open_file(
1414                                 vstream->stream_file.trace_chunk,
1415                                 file_path, O_RDONLY, 0, &fd);
1416                 if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
1417                         PERROR("Failed to open trace file for viewer stream");
1418                         goto error_put;
1419                 }
1420                 vstream->stream_file.fd = stream_fd_create(fd);
1421                 if (!vstream->stream_file.fd) {
1422                         if (close(fd)) {
1423                                 PERROR("Failed to close viewer stream file");
1424                         }
1425                         goto error_put;
1426                 }
1427         }
1428
1429         ret = check_new_streams(conn);
1430         if (ret < 0) {
1431                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1432                 goto send_reply;
1433         } else if (ret == 1) {
1434                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1435         }
1436
1437         ret = lttng_index_file_read(vstream->index_file, &packet_index);
1438         if (ret) {
1439                 ERR("Relay error reading index file %d",
1440                                 vstream->index_file->fd);
1441                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1442                 goto send_reply;
1443         } else {
1444                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_OK);
1445                 vstream->index_sent_seqcount++;
1446         }
1447
1448         /*
1449          * Indexes are stored in big endian, no need to switch before sending.
1450          */
1451         DBG("Sending viewer index for stream %" PRIu64 " offset %" PRIu64,
1452                 rstream->stream_handle,
1453                 (uint64_t) be64toh(packet_index.offset));
1454         viewer_index.offset = packet_index.offset;
1455         viewer_index.packet_size = packet_index.packet_size;
1456         viewer_index.content_size = packet_index.content_size;
1457         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1458         viewer_index.timestamp_end = packet_index.timestamp_end;
1459         viewer_index.events_discarded = packet_index.events_discarded;
1460         viewer_index.stream_id = packet_index.stream_id;
1461
1462 send_reply:
1463         if (rstream) {
1464                 pthread_mutex_unlock(&rstream->lock);
1465         }
1466
1467         if (metadata_viewer_stream) {
1468                 pthread_mutex_lock(&metadata_viewer_stream->stream->lock);
1469                 DBG("get next index metadata check: recv %" PRIu64
1470                                 " sent %" PRIu64,
1471                         metadata_viewer_stream->stream->metadata_received,
1472                         metadata_viewer_stream->metadata_sent);
1473                 if (!metadata_viewer_stream->stream->metadata_received ||
1474                                 metadata_viewer_stream->stream->metadata_received >
1475                                         metadata_viewer_stream->metadata_sent) {
1476                         viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1477                 }
1478                 pthread_mutex_unlock(&metadata_viewer_stream->stream->lock);
1479         }
1480
1481         viewer_index.flags = htobe32(viewer_index.flags);
1482         health_code_update();
1483
1484         ret = send_response(conn->sock, &viewer_index, sizeof(viewer_index));
1485         if (ret < 0) {
1486                 goto end;
1487         }
1488         health_code_update();
1489
1490         if (vstream) {
1491                 DBG("Index %" PRIu64 " for stream %" PRIu64 " sent",
1492                                 vstream->index_sent_seqcount,
1493                                 vstream->stream->stream_handle);
1494         }
1495 end:
1496         if (metadata_viewer_stream) {
1497                 viewer_stream_put(metadata_viewer_stream);
1498         }
1499         if (vstream) {
1500                 viewer_stream_put(vstream);
1501         }
1502         return ret;
1503
1504 error_put:
1505         pthread_mutex_unlock(&rstream->lock);
1506         if (metadata_viewer_stream) {
1507                 viewer_stream_put(metadata_viewer_stream);
1508         }
1509         viewer_stream_put(vstream);
1510         return ret;
1511 }
1512
1513 /*
1514  * Send the next index for a stream
1515  *
1516  * Return 0 on success or else a negative value.
1517  */
1518 static
1519 int viewer_get_packet(struct relay_connection *conn)
1520 {
1521         int ret;
1522         off_t lseek_ret;
1523         char *reply = NULL;
1524         struct lttng_viewer_get_packet get_packet_info;
1525         struct lttng_viewer_trace_packet reply_header;
1526         struct relay_viewer_stream *vstream = NULL;
1527         uint32_t reply_size = sizeof(reply_header);
1528         uint32_t packet_data_len = 0;
1529         ssize_t read_len;
1530
1531         DBG2("Relay get data packet");
1532
1533         health_code_update();
1534
1535         ret = recv_request(conn->sock, &get_packet_info,
1536                         sizeof(get_packet_info));
1537         if (ret < 0) {
1538                 goto end;
1539         }
1540         health_code_update();
1541
1542         /* From this point on, the error label can be reached. */
1543         memset(&reply_header, 0, sizeof(reply_header));
1544
1545         vstream = viewer_stream_get_by_id(be64toh(get_packet_info.stream_id));
1546         if (!vstream) {
1547                 DBG("Client requested packet of unknown stream id %" PRIu64,
1548                                 (uint64_t) be64toh(get_packet_info.stream_id));
1549                 reply_header.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1550                 goto send_reply_nolock;
1551         } else {
1552                 packet_data_len = be32toh(get_packet_info.len);
1553                 reply_size += packet_data_len;
1554         }
1555
1556         reply = zmalloc(reply_size);
1557         if (!reply) {
1558                 PERROR("packet reply zmalloc");
1559                 reply_size = sizeof(reply_header);
1560                 goto error;
1561         }
1562
1563         pthread_mutex_lock(&vstream->stream->lock);
1564         lseek_ret = lseek(vstream->stream_file.fd->fd,
1565                         be64toh(get_packet_info.offset), SEEK_SET);
1566         if (lseek_ret < 0) {
1567                 PERROR("lseek fd %d to offset %" PRIu64,
1568                                 vstream->stream_file.fd->fd,
1569                                 (uint64_t) be64toh(get_packet_info.offset));
1570                 goto error;
1571         }
1572         read_len = lttng_read(vstream->stream_file.fd->fd,
1573                         reply + sizeof(reply_header), packet_data_len);
1574         if (read_len < packet_data_len) {
1575                 PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1576                                 vstream->stream_file.fd->fd,
1577                                 (uint64_t) be64toh(get_packet_info.offset));
1578                 goto error;
1579         }
1580         reply_header.status = htobe32(LTTNG_VIEWER_GET_PACKET_OK);
1581         reply_header.len = htobe32(packet_data_len);
1582         goto send_reply;
1583
1584 error:
1585         reply_header.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1586
1587 send_reply:
1588         if (vstream) {
1589                 pthread_mutex_unlock(&vstream->stream->lock);
1590         }
1591 send_reply_nolock:
1592
1593         health_code_update();
1594
1595         if (reply) {
1596                 memcpy(reply, &reply_header, sizeof(reply_header));
1597                 ret = send_response(conn->sock, reply, reply_size);
1598         } else {
1599                 /* No reply to send. */
1600                 ret = send_response(conn->sock, &reply_header,
1601                                 reply_size);
1602         }
1603
1604         health_code_update();
1605         if (ret < 0) {
1606                 PERROR("sendmsg of packet data failed");
1607                 goto end_free;
1608         }
1609
1610         DBG("Sent %u bytes for stream %" PRIu64, reply_size,
1611                         (uint64_t) be64toh(get_packet_info.stream_id));
1612
1613 end_free:
1614         free(reply);
1615 end:
1616         if (vstream) {
1617                 viewer_stream_put(vstream);
1618         }
1619         return ret;
1620 }
1621
1622 /*
1623  * Send the session's metadata
1624  *
1625  * Return 0 on success else a negative value.
1626  */
1627 static
1628 int viewer_get_metadata(struct relay_connection *conn)
1629 {
1630         int ret = 0;
1631         ssize_t read_len;
1632         uint64_t len = 0;
1633         char *data = NULL;
1634         struct lttng_viewer_get_metadata request;
1635         struct lttng_viewer_metadata_packet reply;
1636         struct relay_viewer_stream *vstream = NULL;
1637
1638         assert(conn);
1639
1640         DBG("Relay get metadata");
1641
1642         health_code_update();
1643
1644         ret = recv_request(conn->sock, &request, sizeof(request));
1645         if (ret < 0) {
1646                 goto end;
1647         }
1648         health_code_update();
1649
1650         memset(&reply, 0, sizeof(reply));
1651
1652         vstream = viewer_stream_get_by_id(be64toh(request.stream_id));
1653         if (!vstream) {
1654                 /*
1655                  * The metadata stream can be closed by a CLOSE command
1656                  * just before we attach. It can also be closed by
1657                  * per-pid tracing during tracing. Therefore, it is
1658                  * possible that we cannot find this viewer stream.
1659                  * Reply back to the client with an error if we cannot
1660                  * find it.
1661                  */
1662                 DBG("Client requested metadata of unknown stream id %" PRIu64,
1663                                 (uint64_t) be64toh(request.stream_id));
1664                 reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1665                 goto send_reply;
1666         }
1667         pthread_mutex_lock(&vstream->stream->lock);
1668         if (!vstream->stream->is_metadata) {
1669                 ERR("Invalid metadata stream");
1670                 goto error;
1671         }
1672
1673         assert(vstream->metadata_sent <= vstream->stream->metadata_received);
1674
1675         len = vstream->stream->metadata_received - vstream->metadata_sent;
1676         if (len == 0) {
1677                 reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
1678                 goto send_reply;
1679         }
1680
1681         /* first time, we open the metadata file */
1682         if (!vstream->stream_file.fd) {
1683                 int fd;
1684                 char file_path[LTTNG_PATH_MAX];
1685                 enum lttng_trace_chunk_status status;
1686                 struct relay_stream *rstream = vstream->stream;
1687
1688                 ret = utils_stream_file_path(rstream->path_name,
1689                                 rstream->channel_name, rstream->tracefile_size,
1690                                 vstream->current_tracefile_id, NULL, file_path,
1691                                 sizeof(file_path));
1692                 if (ret < 0) {
1693                         goto error;
1694                 }
1695
1696                 status = lttng_trace_chunk_open_file(
1697                                 vstream->stream_file.trace_chunk,
1698                                 file_path, O_RDONLY, 0, &fd);
1699                 if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
1700                         PERROR("Failed to open metadata file for viewer stream");
1701                         goto error;
1702                 }
1703                 vstream->stream_file.fd = stream_fd_create(fd);
1704                 if (!vstream->stream_file.fd) {
1705                         if (close(fd)) {
1706                                 PERROR("Failed to close viewer metadata file");
1707                         }
1708                         goto error;
1709                 }
1710         }
1711
1712         reply.len = htobe64(len);
1713         data = zmalloc(len);
1714         if (!data) {
1715                 PERROR("viewer metadata zmalloc");
1716                 goto error;
1717         }
1718
1719         read_len = lttng_read(vstream->stream_file.fd->fd, data, len);
1720         if (read_len < len) {
1721                 PERROR("Relay reading metadata file");
1722                 goto error;
1723         }
1724         vstream->metadata_sent += read_len;
1725         if (vstream->metadata_sent == vstream->stream->metadata_received
1726                         && vstream->stream->closed) {
1727                 /* Release ownership for the viewer metadata stream. */
1728                 viewer_stream_put(vstream);
1729         }
1730
1731         reply.status = htobe32(LTTNG_VIEWER_METADATA_OK);
1732
1733         goto send_reply;
1734
1735 error:
1736         reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1737
1738 send_reply:
1739         health_code_update();
1740         if (vstream) {
1741                 pthread_mutex_unlock(&vstream->stream->lock);
1742         }
1743         ret = send_response(conn->sock, &reply, sizeof(reply));
1744         if (ret < 0) {
1745                 goto end_free;
1746         }
1747         health_code_update();
1748
1749         if (len > 0) {
1750                 ret = send_response(conn->sock, data, len);
1751                 if (ret < 0) {
1752                         goto end_free;
1753                 }
1754         }
1755
1756         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1757                         (uint64_t) be64toh(request.stream_id));
1758
1759         DBG("Metadata sent");
1760
1761 end_free:
1762         free(data);
1763 end:
1764         if (vstream) {
1765                 viewer_stream_put(vstream);
1766         }
1767         return ret;
1768 }
1769
1770 /*
1771  * Create a viewer session.
1772  *
1773  * Return 0 on success or else a negative value.
1774  */
1775 static
1776 int viewer_create_session(struct relay_connection *conn)
1777 {
1778         int ret;
1779         struct lttng_viewer_create_session_response resp;
1780
1781         DBG("Viewer create session received");
1782
1783         memset(&resp, 0, sizeof(resp));
1784         resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_OK);
1785         conn->viewer_session = viewer_session_create();
1786         if (!conn->viewer_session) {
1787                 ERR("Allocation viewer session");
1788                 resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_ERR);
1789                 goto send_reply;
1790         }
1791
1792 send_reply:
1793         health_code_update();
1794         ret = send_response(conn->sock, &resp, sizeof(resp));
1795         if (ret < 0) {
1796                 goto end;
1797         }
1798         health_code_update();
1799         ret = 0;
1800
1801 end:
1802         return ret;
1803 }
1804
1805 /*
1806  * Detach a viewer session.
1807  *
1808  * Return 0 on success or else a negative value.
1809  */
1810 static
1811 int viewer_detach_session(struct relay_connection *conn)
1812 {
1813         int ret;
1814         struct lttng_viewer_detach_session_response response;
1815         struct lttng_viewer_detach_session_request request;
1816         struct relay_session *session = NULL;
1817         uint64_t viewer_session_to_close;
1818
1819         DBG("Viewer detach session received");
1820
1821         assert(conn);
1822
1823         health_code_update();
1824
1825         /* Receive the request from the connected client. */
1826         ret = recv_request(conn->sock, &request, sizeof(request));
1827         if (ret < 0) {
1828                 goto end;
1829         }
1830         viewer_session_to_close = be64toh(request.session_id);
1831
1832         if (!conn->viewer_session) {
1833                 DBG("Client trying to detach before creating a live viewer session");
1834                 response.status = htobe32(LTTNG_VIEWER_DETACH_SESSION_ERR);
1835                 goto send_reply;
1836         }
1837
1838         health_code_update();
1839
1840         memset(&response, 0, sizeof(response));
1841         DBG("Detaching from session ID %" PRIu64, viewer_session_to_close);
1842
1843         session = session_get_by_id(be64toh(request.session_id));
1844         if (!session) {
1845                 DBG("Relay session %" PRIu64 " not found",
1846                                 (uint64_t) be64toh(request.session_id));
1847                 response.status = htobe32(LTTNG_VIEWER_DETACH_SESSION_UNK);
1848                 goto send_reply;
1849         }
1850
1851         ret = viewer_session_is_attached(conn->viewer_session, session);
1852         if (ret != 1) {
1853                 DBG("Not attached to this session");
1854                 response.status = htobe32(LTTNG_VIEWER_DETACH_SESSION_ERR);
1855                 goto send_reply_put;
1856         }
1857
1858         viewer_session_close_one_session(conn->viewer_session, session);
1859         response.status = htobe32(LTTNG_VIEWER_DETACH_SESSION_OK);
1860         DBG("Session %" PRIu64 " detached.", viewer_session_to_close);
1861
1862 send_reply_put:
1863         session_put(session);
1864
1865 send_reply:
1866         health_code_update();
1867         ret = send_response(conn->sock, &response, sizeof(response));
1868         if (ret < 0) {
1869                 goto end;
1870         }
1871         health_code_update();
1872         ret = 0;
1873
1874 end:
1875         return ret;
1876 }
1877
1878 /*
1879  * live_relay_unknown_command: send -1 if received unknown command
1880  */
1881 static
1882 void live_relay_unknown_command(struct relay_connection *conn)
1883 {
1884         struct lttcomm_relayd_generic_reply reply;
1885
1886         memset(&reply, 0, sizeof(reply));
1887         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1888         (void) send_response(conn->sock, &reply, sizeof(reply));
1889 }
1890
1891 /*
1892  * Process the commands received on the control socket
1893  */
1894 static
1895 int process_control(struct lttng_viewer_cmd *recv_hdr,
1896                 struct relay_connection *conn)
1897 {
1898         int ret = 0;
1899         uint32_t msg_value;
1900
1901         msg_value = be32toh(recv_hdr->cmd);
1902
1903         /*
1904          * Make sure we've done the version check before any command other then a
1905          * new client connection.
1906          */
1907         if (msg_value != LTTNG_VIEWER_CONNECT && !conn->version_check_done) {
1908                 ERR("Viewer conn value %" PRIu32 " before version check", msg_value);
1909                 ret = -1;
1910                 goto end;
1911         }
1912
1913         switch (msg_value) {
1914         case LTTNG_VIEWER_CONNECT:
1915                 ret = viewer_connect(conn);
1916                 break;
1917         case LTTNG_VIEWER_LIST_SESSIONS:
1918                 ret = viewer_list_sessions(conn);
1919                 break;
1920         case LTTNG_VIEWER_ATTACH_SESSION:
1921                 ret = viewer_attach_session(conn);
1922                 break;
1923         case LTTNG_VIEWER_GET_NEXT_INDEX:
1924                 ret = viewer_get_next_index(conn);
1925                 break;
1926         case LTTNG_VIEWER_GET_PACKET:
1927                 ret = viewer_get_packet(conn);
1928                 break;
1929         case LTTNG_VIEWER_GET_METADATA:
1930                 ret = viewer_get_metadata(conn);
1931                 break;
1932         case LTTNG_VIEWER_GET_NEW_STREAMS:
1933                 ret = viewer_get_new_streams(conn);
1934                 break;
1935         case LTTNG_VIEWER_CREATE_SESSION:
1936                 ret = viewer_create_session(conn);
1937                 break;
1938         case LTTNG_VIEWER_DETACH_SESSION:
1939                 ret = viewer_detach_session(conn);
1940                 break;
1941         default:
1942                 ERR("Received unknown viewer command (%u)",
1943                                 be32toh(recv_hdr->cmd));
1944                 live_relay_unknown_command(conn);
1945                 ret = -1;
1946                 goto end;
1947         }
1948
1949 end:
1950         return ret;
1951 }
1952
1953 static
1954 void cleanup_connection_pollfd(struct lttng_poll_event *events, int pollfd)
1955 {
1956         int ret;
1957
1958         (void) lttng_poll_del(events, pollfd);
1959
1960         ret = close(pollfd);
1961         if (ret < 0) {
1962                 ERR("Closing pollfd %d", pollfd);
1963         }
1964 }
1965
1966 /*
1967  * This thread does the actual work
1968  */
1969 static
1970 void *thread_worker(void *data)
1971 {
1972         int ret, err = -1;
1973         uint32_t nb_fd;
1974         struct lttng_poll_event events;
1975         struct lttng_ht *viewer_connections_ht;
1976         struct lttng_ht_iter iter;
1977         struct lttng_viewer_cmd recv_hdr;
1978         struct relay_connection *destroy_conn;
1979
1980         DBG("[thread] Live viewer relay worker started");
1981
1982         rcu_register_thread();
1983
1984         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1985
1986         if (testpoint(relayd_thread_live_worker)) {
1987                 goto error_testpoint;
1988         }
1989
1990         /* table of connections indexed on socket */
1991         viewer_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1992         if (!viewer_connections_ht) {
1993                 goto viewer_connections_ht_error;
1994         }
1995
1996         ret = create_thread_poll_set(&events, 2);
1997         if (ret < 0) {
1998                 goto error_poll_create;
1999         }
2000
2001         ret = lttng_poll_add(&events, live_conn_pipe[0], LPOLLIN | LPOLLRDHUP);
2002         if (ret < 0) {
2003                 goto error;
2004         }
2005
2006 restart:
2007         while (1) {
2008                 int i;
2009
2010                 health_code_update();
2011
2012                 /* Infinite blocking call, waiting for transmission */
2013                 DBG3("Relayd live viewer worker thread polling...");
2014                 health_poll_entry();
2015                 ret = lttng_poll_wait(&events, -1);
2016                 health_poll_exit();
2017                 if (ret < 0) {
2018                         /*
2019                          * Restart interrupted system call.
2020                          */
2021                         if (errno == EINTR) {
2022                                 goto restart;
2023                         }
2024                         goto error;
2025                 }
2026
2027                 nb_fd = ret;
2028
2029                 /*
2030                  * Process control. The control connection is prioritised so we don't
2031                  * starve it with high throughput tracing data on the data
2032                  * connection.
2033                  */
2034                 for (i = 0; i < nb_fd; i++) {
2035                         /* Fetch once the poll data */
2036                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
2037                         int pollfd = LTTNG_POLL_GETFD(&events, i);
2038
2039                         health_code_update();
2040
2041                         /* Thread quit pipe has been closed. Killing thread. */
2042                         ret = check_thread_quit_pipe(pollfd, revents);
2043                         if (ret) {
2044                                 err = 0;
2045                                 goto exit;
2046                         }
2047
2048                         /* Inspect the relay conn pipe for new connection. */
2049                         if (pollfd == live_conn_pipe[0]) {
2050                                 if (revents & LPOLLIN) {
2051                                         struct relay_connection *conn;
2052
2053                                         ret = lttng_read(live_conn_pipe[0],
2054                                                         &conn, sizeof(conn));
2055                                         if (ret < 0) {
2056                                                 goto error;
2057                                         }
2058                                         ret = lttng_poll_add(&events,
2059                                                         conn->sock->fd,
2060                                                         LPOLLIN | LPOLLRDHUP);
2061                                         if (ret) {
2062                                                 ERR("Failed to add new live connection file descriptor to poll set");
2063                                                 goto error;
2064                                         }
2065                                         connection_ht_add(viewer_connections_ht, conn);
2066                                         DBG("Connection socket %d added to poll", conn->sock->fd);
2067                                 } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
2068                                         ERR("Relay live pipe error");
2069                                         goto error;
2070                                 } else {
2071                                         ERR("Unexpected poll events %u for sock %d", revents, pollfd);
2072                                         goto error;
2073                                 }
2074                         } else {
2075                                 /* Connection activity. */
2076                                 struct relay_connection *conn;
2077
2078                                 conn = connection_get_by_sock(viewer_connections_ht, pollfd);
2079                                 if (!conn) {
2080                                         continue;
2081                                 }
2082
2083                                 if (revents & LPOLLIN) {
2084                                         ret = conn->sock->ops->recvmsg(conn->sock, &recv_hdr,
2085                                                         sizeof(recv_hdr), 0);
2086                                         if (ret <= 0) {
2087                                                 /* Connection closed. */
2088                                                 cleanup_connection_pollfd(&events, pollfd);
2089                                                 /* Put "create" ownership reference. */
2090                                                 connection_put(conn);
2091                                                 DBG("Viewer control conn closed with %d", pollfd);
2092                                         } else {
2093                                                 ret = process_control(&recv_hdr, conn);
2094                                                 if (ret < 0) {
2095                                                         /* Clear the session on error. */
2096                                                         cleanup_connection_pollfd(&events, pollfd);
2097                                                         /* Put "create" ownership reference. */
2098                                                         connection_put(conn);
2099                                                         DBG("Viewer connection closed with %d", pollfd);
2100                                                 }
2101                                         }
2102                                 } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
2103                                         cleanup_connection_pollfd(&events, pollfd);
2104                                         /* Put "create" ownership reference. */
2105                                         connection_put(conn);
2106                                 } else {
2107                                         ERR("Unexpected poll events %u for sock %d", revents, pollfd);
2108                                         connection_put(conn);
2109                                         goto error;
2110                                 }
2111                                 /* Put local "get_by_sock" reference. */
2112                                 connection_put(conn);
2113                         }
2114                 }
2115         }
2116
2117 exit:
2118 error:
2119         lttng_poll_clean(&events);
2120
2121         /* Cleanup remaining connection object. */
2122         rcu_read_lock();
2123         cds_lfht_for_each_entry(viewer_connections_ht->ht, &iter.iter,
2124                         destroy_conn,
2125                         sock_n.node) {
2126                 health_code_update();
2127                 connection_put(destroy_conn);
2128         }
2129         rcu_read_unlock();
2130 error_poll_create:
2131         lttng_ht_destroy(viewer_connections_ht);
2132 viewer_connections_ht_error:
2133         /* Close relay conn pipes */
2134         utils_close_pipe(live_conn_pipe);
2135         if (err) {
2136                 DBG("Viewer worker thread exited with error");
2137         }
2138         DBG("Viewer worker thread cleanup complete");
2139 error_testpoint:
2140         if (err) {
2141                 health_error();
2142                 ERR("Health error occurred in %s", __func__);
2143         }
2144         health_unregister(health_relayd);
2145         if (lttng_relay_stop_threads()) {
2146                 ERR("Error stopping threads");
2147         }
2148         rcu_unregister_thread();
2149         return NULL;
2150 }
2151
2152 /*
2153  * Create the relay command pipe to wake thread_manage_apps.
2154  * Closed in cleanup().
2155  */
2156 static int create_conn_pipe(void)
2157 {
2158         return utils_create_pipe_cloexec(live_conn_pipe);
2159 }
2160
2161 int relayd_live_join(void)
2162 {
2163         int ret, retval = 0;
2164         void *status;
2165
2166         ret = pthread_join(live_listener_thread, &status);
2167         if (ret) {
2168                 errno = ret;
2169                 PERROR("pthread_join live listener");
2170                 retval = -1;
2171         }
2172
2173         ret = pthread_join(live_worker_thread, &status);
2174         if (ret) {
2175                 errno = ret;
2176                 PERROR("pthread_join live worker");
2177                 retval = -1;
2178         }
2179
2180         ret = pthread_join(live_dispatcher_thread, &status);
2181         if (ret) {
2182                 errno = ret;
2183                 PERROR("pthread_join live dispatcher");
2184                 retval = -1;
2185         }
2186
2187         cleanup_relayd_live();
2188
2189         return retval;
2190 }
2191
2192 /*
2193  * main
2194  */
2195 int relayd_live_create(struct lttng_uri *uri)
2196 {
2197         int ret = 0, retval = 0;
2198         void *status;
2199         int is_root;
2200
2201         if (!uri) {
2202                 retval = -1;
2203                 goto exit_init_data;
2204         }
2205         live_uri = uri;
2206
2207         /* Check if daemon is UID = 0 */
2208         is_root = !getuid();
2209
2210         if (!is_root) {
2211                 if (live_uri->port < 1024) {
2212                         ERR("Need to be root to use ports < 1024");
2213                         retval = -1;
2214                         goto exit_init_data;
2215                 }
2216         }
2217
2218         /* Setup the thread apps communication pipe. */
2219         if (create_conn_pipe()) {
2220                 retval = -1;
2221                 goto exit_init_data;
2222         }
2223
2224         /* Init relay command queue. */
2225         cds_wfcq_init(&viewer_conn_queue.head, &viewer_conn_queue.tail);
2226
2227         /* Set up max poll set size */
2228         if (lttng_poll_set_max_size()) {
2229                 retval = -1;
2230                 goto exit_init_data;
2231         }
2232
2233         /* Setup the dispatcher thread */
2234         ret = pthread_create(&live_dispatcher_thread, default_pthread_attr(),
2235                         thread_dispatcher, (void *) NULL);
2236         if (ret) {
2237                 errno = ret;
2238                 PERROR("pthread_create viewer dispatcher");
2239                 retval = -1;
2240                 goto exit_dispatcher_thread;
2241         }
2242
2243         /* Setup the worker thread */
2244         ret = pthread_create(&live_worker_thread, default_pthread_attr(),
2245                         thread_worker, NULL);
2246         if (ret) {
2247                 errno = ret;
2248                 PERROR("pthread_create viewer worker");
2249                 retval = -1;
2250                 goto exit_worker_thread;
2251         }
2252
2253         /* Setup the listener thread */
2254         ret = pthread_create(&live_listener_thread, default_pthread_attr(),
2255                         thread_listener, (void *) NULL);
2256         if (ret) {
2257                 errno = ret;
2258                 PERROR("pthread_create viewer listener");
2259                 retval = -1;
2260                 goto exit_listener_thread;
2261         }
2262
2263         /*
2264          * All OK, started all threads.
2265          */
2266         return retval;
2267
2268         /*
2269          * Join on the live_listener_thread should anything be added after
2270          * the live_listener thread's creation.
2271          */
2272
2273 exit_listener_thread:
2274
2275         ret = pthread_join(live_worker_thread, &status);
2276         if (ret) {
2277                 errno = ret;
2278                 PERROR("pthread_join live worker");
2279                 retval = -1;
2280         }
2281 exit_worker_thread:
2282
2283         ret = pthread_join(live_dispatcher_thread, &status);
2284         if (ret) {
2285                 errno = ret;
2286                 PERROR("pthread_join live dispatcher");
2287                 retval = -1;
2288         }
2289 exit_dispatcher_thread:
2290
2291 exit_init_data:
2292         cleanup_relayd_live();
2293
2294         return retval;
2295 }