src/bin/lttng-relayd/live.c

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