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_wfcq_enqueue(&viewer_conn_queue.head, &viewer_conn_queue.tail,
 567                                                  &new_conn->qnode);
 568
 569                                 /*
 570                                  * Wake the dispatch queue futex. Implicit memory barrier with
 571                                  * the exchange in cds_wfcq_enqueue.
 572                                  */
 573                                 futex_nto1_wake(&viewer_conn_queue.futex);
 574                         }
 575                 }
 576         }
 577
 578 exit:
 579 error:
 580 error_poll_add:
 581 error_testpoint:
 582         lttng_poll_clean(&events);
 583 error_create_poll:
 584         if (live_control_sock->fd >= 0) {
 585                 ret = live_control_sock->ops->close(live_control_sock);
 586                 if (ret) {
 587                         PERROR("close");
 588                 }
 589         }
 590         lttcomm_destroy_sock(live_control_sock);
 591 error_sock_control:
 592         if (err) {
 593                 health_error();
 594                 DBG("Live viewer listener thread exited with error");
 595         }
 596         health_unregister(health_relayd);
 597         DBG("Live viewer listener thread cleanup complete");
 598         stop_threads();
 599         return NULL;
 600 }
 601
 602 /*
 603  * This thread manages the dispatching of the requests to worker threads
 604  */
 605 static
 606 void *thread_dispatcher(void *data)
 607 {
 608         int err = -1;
 609         ssize_t ret;
 610         struct cds_wfcq_node *node;
 611         struct relay_connection *conn = NULL;
 612
 613         DBG("[thread] Live viewer relay dispatcher started");
 614
 615         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 616
 617         if (testpoint(relayd_thread_live_dispatcher)) {
 618                 goto error_testpoint;
 619         }
 620
 621         health_code_update();
 622
 623         while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 624                 health_code_update();
 625
 626                 /* Atomically prepare the queue futex */
 627                 futex_nto1_prepare(&viewer_conn_queue.futex);
 628
 629                 do {
 630                         health_code_update();
 631
 632                         /* Dequeue commands */
 633                         node = cds_wfcq_dequeue_blocking(&viewer_conn_queue.head,
 634                                                          &viewer_conn_queue.tail);
 635                         if (node == NULL) {
 636                                 DBG("Woken up but nothing in the live-viewer "
 637                                                 "relay command queue");
 638                                 /* Continue thread execution */
 639                                 break;
 640                         }
 641                         conn = caa_container_of(node, struct relay_connection, qnode);
 642                         DBG("Dispatching viewer request waiting on sock %d",
 643                                         conn->sock->fd);
 644
 645                         /*
 646                          * Inform worker thread of the new request. This call is blocking
 647                          * so we can be assured that the data will be read at some point in
 648                          * time or wait to the end of the world :)
 649                          */
 650                         ret = lttng_write(live_conn_pipe[1], &conn, sizeof(conn));
 651                         if (ret < 0) {
 652                                 PERROR("write conn pipe");
 653                                 connection_destroy(conn);
 654                                 goto error;
 655                         }
 656                 } while (node != NULL);
 657
 658                 /* Futex wait on queue. Blocking call on futex() */
 659                 health_poll_entry();
 660                 futex_nto1_wait(&viewer_conn_queue.futex);
 661                 health_poll_exit();
 662         }
 663
 664         /* Normal exit, no error */
 665         err = 0;
 666
 667 error:
 668 error_testpoint:
 669         if (err) {
 670                 health_error();
 671                 ERR("Health error occurred in %s", __func__);
 672         }
 673         health_unregister(health_relayd);
 674         DBG("Live viewer dispatch thread dying");
 675         stop_threads();
 676         return NULL;
 677 }
 678
 679 /*
 680  * Establish connection with the viewer and check the versions.
 681  *
 682  * Return 0 on success or else negative value.
 683  */
 684 static
 685 int viewer_connect(struct relay_connection *conn)
 686 {
 687         int ret;
 688         struct lttng_viewer_connect reply, msg;
 689
 690         assert(conn);
 691
 692         conn->version_check_done = 1;
 693
 694         health_code_update();
 695
 696         DBG("Viewer is establishing a connection to the relayd.");
 697
 698         ret = recv_request(conn->sock, &msg, sizeof(msg));
 699         if (ret < 0) {
 700                 goto end;
 701         }
 702
 703         health_code_update();
 704
 705         memset(&reply, 0, sizeof(reply));
 706         reply.major = RELAYD_VERSION_COMM_MAJOR;
 707         reply.minor = RELAYD_VERSION_COMM_MINOR;
 708
 709         /* Major versions must be the same */
 710         if (reply.major != be32toh(msg.major)) {
 711                 DBG("Incompatible major versions ([relayd] %u vs [client] %u)",
 712                                 reply.major, be32toh(msg.major));
 713                 ret = -1;
 714                 goto end;
 715         }
 716
 717         conn->major = reply.major;
 718         /* We adapt to the lowest compatible version */
 719         if (reply.minor <= be32toh(msg.minor)) {
 720                 conn->minor = reply.minor;
 721         } else {
 722                 conn->minor = be32toh(msg.minor);
 723         }
 724
 725         if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_COMMAND) {
 726                 conn->type = RELAY_VIEWER_COMMAND;
 727         } else if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_NOTIFICATION) {
 728                 conn->type = RELAY_VIEWER_NOTIFICATION;
 729         } else {
 730                 ERR("Unknown connection type : %u", be32toh(msg.type));
 731                 ret = -1;
 732                 goto end;
 733         }
 734
 735         reply.major = htobe32(reply.major);
 736         reply.minor = htobe32(reply.minor);
 737         if (conn->type == RELAY_VIEWER_COMMAND) {
 738                 /*
 739                  * Increment outside of htobe64 macro, because can be used more than once
 740                  * within the macro, and thus the operation may be undefined.
 741                  */
 742                 last_relay_viewer_session_id++;
 743                 reply.viewer_session_id = htobe64(last_relay_viewer_session_id);
 744         }
 745
 746         health_code_update();
 747
 748         ret = send_response(conn->sock, &reply, sizeof(reply));
 749         if (ret < 0) {
 750                 goto end;
 751         }
 752
 753         health_code_update();
 754
 755         DBG("Version check done using protocol %u.%u", conn->major, conn->minor);
 756         ret = 0;
 757
 758 end:
 759         return ret;
 760 }
 761
 762 /*
 763  * Send the viewer the list of current sessions.
 764  *
 765  * Return 0 on success or else a negative value.
 766  */
 767 static
 768 int viewer_list_sessions(struct relay_connection *conn)
 769 {
 770         int ret;
 771         struct lttng_viewer_list_sessions session_list;
 772         unsigned long count;
 773         long approx_before, approx_after;
 774         struct lttng_ht_iter iter;
 775         struct lttng_viewer_session send_session;
 776         struct relay_session *session;
 777
 778         DBG("List sessions received");
 779
 780         rcu_read_lock();
 781         cds_lfht_count_nodes(conn->sessions_ht->ht, &approx_before, &count,
 782                         &approx_after);
 783         session_list.sessions_count = htobe32(count);
 784
 785         health_code_update();
 786
 787         ret = send_response(conn->sock, &session_list, sizeof(session_list));
 788         if (ret < 0) {
 789                 goto end_unlock;
 790         }
 791
 792         health_code_update();
 793
 794         cds_lfht_for_each_entry(conn->sessions_ht->ht, &iter.iter, session,
 795                         session_n.node) {
 796                 health_code_update();
 797
 798                 strncpy(send_session.session_name, session->session_name,
 799                                 sizeof(send_session.session_name));
 800                 strncpy(send_session.hostname, session->hostname,
 801                                 sizeof(send_session.hostname));
 802                 send_session.id = htobe64(session->id);
 803                 send_session.live_timer = htobe32(session->live_timer);
 804                 send_session.clients = htobe32(session->viewer_refcount);
 805                 send_session.streams = htobe32(session->stream_count);
 806
 807                 health_code_update();
 808
 809                 ret = send_response(conn->sock, &send_session, sizeof(send_session));
 810                 if (ret < 0) {
 811                         goto end_unlock;
 812                 }
 813         }
 814         health_code_update();
 815
 816         ret = 0;
 817 end_unlock:
 818         rcu_read_unlock();
 819         return ret;
 820 }
 821
 822 /*
 823  * Check if a connection is attached to a session.
 824  * Return 1 if attached, 0 if not attached, a negative value on error.
 825  */
 826 static
 827 int session_attached(struct relay_connection *conn, uint64_t session_id)
 828 {
 829         struct relay_session *session;
 830         int found = 0;
 831
 832         if (!conn->viewer_session) {
 833                 goto end;
 834         }
 835         cds_list_for_each_entry(session,
 836                         &conn->viewer_session->sessions_head,
 837                         viewer_session_list) {
 838                 if (session->id == session_id) {
 839                         found = 1;
 840                         goto end;
 841                 }
 842         }
 843
 844 end:
 845         return found;
 846 }
 847
 848 /*
 849  * Delete all streams for a specific session ID.
 850  */
 851 static void destroy_viewer_streams_by_session(struct relay_session *session)
 852 {
 853         struct relay_viewer_stream *stream;
 854         struct lttng_ht_iter iter;
 855
 856         assert(session);
 857
 858         rcu_read_lock();
 859         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, stream,
 860                         stream_n.node) {
 861                 struct ctf_trace *ctf_trace;
 862
 863                 health_code_update();
 864                 if (stream->session_id != session->id) {
 865                         continue;
 866                 }
 867
 868                 ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
 869                                 stream->path_name);
 870                 assert(ctf_trace);
 871
 872                 viewer_stream_delete(stream);
 873
 874                 if (stream->metadata_flag) {
 875                         ctf_trace->metadata_sent = 0;
 876                         ctf_trace->viewer_metadata_stream = NULL;
 877                 }
 878
 879                 viewer_stream_destroy(ctf_trace, stream);
 880         }
 881         rcu_read_unlock();
 882 }
 883
 884 static void try_destroy_streams(struct relay_session *session)
 885 {
 886         struct ctf_trace *ctf_trace;
 887         struct lttng_ht_iter iter;
 888
 889         assert(session);
 890
 891         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 892                         node.node) {
 893                 /* Attempt to destroy the ctf trace of that session. */
 894                 ctf_trace_try_destroy(session, ctf_trace);
 895         }
 896 }
 897
 898 /*
 899  * Cleanup a session.
 900  */
 901 static void cleanup_session(struct relay_connection *conn,
 902                 struct relay_session *session)
 903 {
 904         /*
 905          * Very important that this is done before destroying the session so we
 906          * can put back every viewer stream reference from the ctf_trace.
 907          */
 908         destroy_viewer_streams_by_session(session);
 909         try_destroy_streams(session);
 910         cds_list_del(&session->viewer_session_list);
 911         session_viewer_try_destroy(conn->sessions_ht, session);
 912 }
 913
 914 /*
 915  * Send the viewer the list of current sessions.
 916  */
 917 static
 918 int viewer_get_new_streams(struct relay_connection *conn)
 919 {
 920         int ret, send_streams = 0;
 921         uint32_t nb_created = 0, nb_unsent = 0, nb_streams = 0;
 922         struct lttng_viewer_new_streams_request request;
 923         struct lttng_viewer_new_streams_response response;
 924         struct relay_session *session;
 925         uint64_t session_id;
 926
 927         assert(conn);
 928
 929         DBG("Get new streams received");
 930
 931         health_code_update();
 932
 933         /* Receive the request from the connected client. */
 934         ret = recv_request(conn->sock, &request, sizeof(request));
 935         if (ret < 0) {
 936                 goto error;
 937         }
 938         session_id = be64toh(request.session_id);
 939
 940         health_code_update();
 941
 942         memset(&response, 0, sizeof(response));
 943
 944         rcu_read_lock();
 945         session = session_find_by_id(conn->sessions_ht, session_id);
 946         if (!session) {
 947                 DBG("Relay session %" PRIu64 " not found", session_id);
 948                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 949                 goto send_reply;
 950         }
 951
 952         if (!session_attached(conn, session_id)) {
 953                 send_streams = 0;
 954                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 955                 goto send_reply;
 956         }
 957
 958         send_streams = 1;
 959         response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 960
 961         ret = make_viewer_streams(session, LTTNG_VIEWER_SEEK_LAST, NULL, &nb_unsent,
 962                         &nb_created);
 963         if (ret < 0) {
 964                 goto end_unlock;
 965         }
 966         /* Only send back the newly created streams with the unsent ones. */
 967         nb_streams = nb_created + nb_unsent;
 968         response.streams_count = htobe32(nb_streams);
 969
 970         /*
 971          * If the session is closed and we have no new streams to send,
 972          * it means that the viewer has already received the whole trace
 973          * for this session and should now close it.
 974          */
 975         if (nb_streams == 0 && session->close_flag) {
 976                 send_streams = 0;
 977                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
 978                 /*
 979                  * Remove the session from the attached list of the connection
 980                  * and try to destroy it.
 981                  */
 982                 cds_list_del(&session->viewer_session_list);
 983                 cleanup_session(conn, session);
 984                 goto send_reply;
 985         }
 986
 987 send_reply:
 988         health_code_update();
 989         ret = send_response(conn->sock, &response, sizeof(response));
 990         if (ret < 0) {
 991                 goto end_unlock;
 992         }
 993         health_code_update();
 994
 995         /*
 996          * Unknown or empty session, just return gracefully, the viewer knows what
 997          * is happening.
 998          */
 999         if (!send_streams || !nb_streams) {
1000                 ret = 0;
1001                 goto end_unlock;
1002         }
1003
1004         /*
1005          * Send stream and *DON'T* ignore the sent flag so every viewer streams
1006          * that were not sent from that point will be sent to the viewer.
1007          */
1008         ret = send_viewer_streams(conn->sock, session, 0);
1009         if (ret < 0) {
1010                 goto end_unlock;
1011         }
1012
1013 end_unlock:
1014         rcu_read_unlock();
1015 error:
1016         return ret;
1017 }
1018
1019 /*
1020  * Send the viewer the list of current sessions.
1021  */
1022 static
1023 int viewer_attach_session(struct relay_connection *conn)
1024 {
1025         int send_streams = 0;
1026         ssize_t ret;
1027         uint32_t nb_streams = 0;
1028         enum lttng_viewer_seek seek_type;
1029         struct lttng_viewer_attach_session_request request;
1030         struct lttng_viewer_attach_session_response response;
1031         struct relay_session *session;
1032
1033         assert(conn);
1034
1035         health_code_update();
1036
1037         /* Receive the request from the connected client. */
1038         ret = recv_request(conn->sock, &request, sizeof(request));
1039         if (ret < 0) {
1040                 goto error;
1041         }
1042
1043         health_code_update();
1044
1045         memset(&response, 0, sizeof(response));
1046
1047         if (!conn->viewer_session) {
1048                 DBG("Client trying to attach before creating a live viewer session");
1049                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NO_SESSION);
1050                 goto send_reply;
1051         }
1052
1053         rcu_read_lock();
1054         session = session_find_by_id(conn->sessions_ht,
1055                         be64toh(request.session_id));
1056         if (!session) {
1057                 DBG("Relay session %" PRIu64 " not found",
1058                                 be64toh(request.session_id));
1059                 response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
1060                 goto send_reply;
1061         }
1062         session_viewer_attach(session);
1063         DBG("Attach session ID %" PRIu64 " received", be64toh(request.session_id));
1064
1065         if (uatomic_read(&session->viewer_refcount) > 1) {
1066                 DBG("Already a viewer attached");
1067                 response.status = htobe32(LTTNG_VIEWER_ATTACH_ALREADY);
1068                 session_viewer_detach(session);
1069                 goto send_reply;
1070         } else if (session->live_timer == 0) {
1071                 DBG("Not live session");
1072                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NOT_LIVE);
1073                 goto send_reply;
1074         } else {
1075                 send_streams = 1;
1076                 response.status = htobe32(LTTNG_VIEWER_ATTACH_OK);
1077                 cds_list_add(&session->viewer_session_list,
1078                                 &conn->viewer_session->sessions_head);
1079         }
1080
1081         switch (be32toh(request.seek)) {
1082         case LTTNG_VIEWER_SEEK_BEGINNING:
1083         case LTTNG_VIEWER_SEEK_LAST:
1084                 seek_type = be32toh(request.seek);
1085                 break;
1086         default:
1087                 ERR("Wrong seek parameter");
1088                 response.status = htobe32(LTTNG_VIEWER_ATTACH_SEEK_ERR);
1089                 send_streams = 0;
1090                 goto send_reply;
1091         }
1092
1093         ret = make_viewer_streams(session, seek_type, &nb_streams, NULL, NULL);
1094         if (ret < 0) {
1095                 goto end_unlock;
1096         }
1097         response.streams_count = htobe32(nb_streams);
1098
1099 send_reply:
1100         health_code_update();
1101         ret = send_response(conn->sock, &response, sizeof(response));
1102         if (ret < 0) {
1103                 goto end_unlock;
1104         }
1105         health_code_update();
1106
1107         /*
1108          * Unknown or empty session, just return gracefully, the viewer knows what
1109          * is happening.
1110          */
1111         if (!send_streams || !nb_streams) {
1112                 ret = 0;
1113                 goto end_unlock;
1114         }
1115
1116         /* Send stream and ignore the sent flag. */
1117         ret = send_viewer_streams(conn->sock, session, 1);
1118         if (ret < 0) {
1119                 goto end_unlock;
1120         }
1121
1122 end_unlock:
1123         rcu_read_unlock();
1124 error:
1125         return ret;
1126 }
1127
1128 /*
1129  * Open the index file if needed for the given vstream.
1130  *
1131  * If an index file is successfully opened, the index_read_fd of the stream is
1132  * set with it.
1133  *
1134  * Return 0 on success, a negative value on error (-ENOENT if not ready yet).
1135  */
1136 static int try_open_index(struct relay_viewer_stream *vstream,
1137                 struct relay_stream *rstream)
1138 {
1139         int ret = 0;
1140
1141         assert(vstream);
1142         assert(rstream);
1143
1144         if (vstream->index_read_fd >= 0) {
1145                 goto end;
1146         }
1147
1148         /*
1149          * First time, we open the index file and at least one index is ready.  The
1150          * race between the read and write of the total_index_received is
1151          * acceptable here since the client will be notified to simply come back
1152          * and get the next index.
1153          */
1154         if (rstream->total_index_received <= 0) {
1155                 ret = -ENOENT;
1156                 goto end;
1157         }
1158         ret = index_open(vstream->path_name, vstream->channel_name,
1159                         vstream->tracefile_count, vstream->tracefile_count_current);
1160         if (ret >= 0) {
1161                 vstream->index_read_fd = ret;
1162                 ret = 0;
1163                 goto end;
1164         }
1165
1166 end:
1167         return ret;
1168 }
1169
1170 /*
1171  * Check the status of the index for the given stream. This function updates
1172  * the index structure if needed and can destroy the vstream also for the HUP
1173  * situation.
1174  *
1175  * Return 0 means that we can proceed with the index. A value of 1 means that
1176  * the index has been updated and is ready to be send to the client. A negative
1177  * value indicates an error that can't be handled.
1178  */
1179 static int check_index_status(struct relay_viewer_stream *vstream,
1180                 struct relay_stream *rstream, struct ctf_trace *trace,
1181                 struct lttng_viewer_index *index)
1182 {
1183         int ret;
1184
1185         assert(vstream);
1186         assert(rstream);
1187         assert(index);
1188         assert(trace);
1189
1190         if (!rstream->close_flag) {
1191                 /* Rotate on abort (overwrite). */
1192                 if (vstream->abort_flag) {
1193                         DBG("Viewer stream %" PRIu64 " rotate because of overwrite",
1194                                         vstream->stream_handle);
1195                         ret = viewer_stream_rotate(vstream, rstream);
1196                         if (ret < 0) {
1197                                 goto error;
1198                         } else if (ret == 1) {
1199                                 /* EOF */
1200                                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1201                                 goto hup;
1202                         }
1203                         /* ret == 0 means successful so we continue. */
1204                 }
1205
1206                 /* Check if we are in the same trace file at this point. */
1207                 if (rstream->tracefile_count_current == vstream->tracefile_count_current) {
1208                         if (rstream->beacon_ts_end != -1ULL &&
1209                                         vstream->last_sent_index == rstream->total_index_received) {
1210                                 /*
1211                                  * We've received a synchronization beacon and the last index
1212                                  * available has been sent, the index for now is inactive.
1213                                  */
1214                                 index->status = htobe32(LTTNG_VIEWER_INDEX_INACTIVE);
1215                                 index->timestamp_end = htobe64(rstream->beacon_ts_end);
1216                                 index->stream_id = htobe64(rstream->ctf_stream_id);
1217                                 goto index_ready;
1218                         } else if (rstream->total_index_received <= vstream->last_sent_index
1219                                         && !vstream->close_write_flag) {
1220                                 /*
1221                                  * Reader and writer are working in the same tracefile, so we care
1222                                  * about the number of index received and sent. Otherwise, we read
1223                                  * up to EOF.
1224                                  */
1225                                 index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1226                                 goto index_ready;
1227                         }
1228                 }
1229                 /* Nothing to do with the index, continue with it. */
1230                 ret = 0;
1231         } else if (rstream->close_flag && vstream->close_write_flag &&
1232                         vstream->total_index_received == vstream->last_sent_index) {
1233                 /* Last index sent and current tracefile closed in write */
1234                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1235                 goto hup;
1236         } else {
1237                 vstream->close_write_flag = 1;
1238                 ret = 0;
1239         }
1240
1241 error:
1242         return ret;
1243
1244 hup:
1245         viewer_stream_delete(vstream);
1246         viewer_stream_destroy(trace, vstream);
1247 index_ready:
1248         return 1;
1249 }
1250
1251 /*
1252  * Send the next index for a stream.
1253  *
1254  * Return 0 on success or else a negative value.
1255  */
1256 static
1257 int viewer_get_next_index(struct relay_connection *conn)
1258 {
1259         int ret;
1260         ssize_t read_ret;
1261         struct lttng_viewer_get_next_index request_index;
1262         struct lttng_viewer_index viewer_index;
1263         struct ctf_packet_index packet_index;
1264         struct relay_viewer_stream *vstream;
1265         struct relay_stream *rstream;
1266         struct ctf_trace *ctf_trace;
1267         struct relay_session *session;
1268
1269         assert(conn);
1270
1271         DBG("Viewer get next index");
1272
1273         health_code_update();
1274
1275         ret = recv_request(conn->sock, &request_index, sizeof(request_index));
1276         if (ret < 0) {
1277                 goto end;
1278         }
1279         health_code_update();
1280
1281         rcu_read_lock();
1282         vstream = viewer_stream_find_by_id(be64toh(request_index.stream_id));
1283         if (!vstream) {
1284                 ret = -1;
1285                 goto end_unlock;
1286         }
1287
1288         session = session_find_by_id(conn->sessions_ht, vstream->session_id);
1289         if (!session) {
1290                 ret = -1;
1291                 goto end_unlock;
1292         }
1293
1294         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht, vstream->path_name);
1295         assert(ctf_trace);
1296
1297         memset(&viewer_index, 0, sizeof(viewer_index));
1298
1299         /*
1300          * The viewer should not ask for index on metadata stream.
1301          */
1302         if (vstream->metadata_flag) {
1303                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1304                 goto send_reply;
1305         }
1306
1307         rstream = stream_find_by_id(relay_streams_ht, vstream->stream_handle);
1308         assert(rstream);
1309
1310         /* Try to open an index if one is needed for that stream. */
1311         ret = try_open_index(vstream, rstream);
1312         if (ret < 0) {
1313                 if (ret == -ENOENT) {
1314                         /*
1315                          * The index is created only when the first data packet arrives, it
1316                          * might not be ready at the beginning of the session
1317                          */
1318                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1319                 } else {
1320                         /* Unhandled error. */
1321                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1322                 }
1323                 goto send_reply;
1324         }
1325
1326         pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1327         ret = check_index_status(vstream, rstream, ctf_trace, &viewer_index);
1328         pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1329         if (ret < 0) {
1330                 goto end_unlock;
1331         } else if (ret == 1) {
1332                 /*
1333                  * This means the viewer index data structure has been populated by the
1334                  * check call thus we now send back the reply to the client.
1335                  */
1336                 goto send_reply;
1337         }
1338         /* At this point, ret MUST be 0 thus we continue with the get. */
1339         assert(!ret);
1340
1341         if (!ctf_trace->metadata_received ||
1342                         ctf_trace->metadata_received > ctf_trace->metadata_sent) {
1343                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1344         }
1345
1346         ret = check_new_streams(conn);
1347         if (ret < 0) {
1348                 goto end_unlock;
1349         } else if (ret == 1) {
1350                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1351         }
1352
1353         pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1354         pthread_mutex_lock(&vstream->overwrite_lock);
1355         if (vstream->abort_flag) {
1356                 /* The file is being overwritten by the writer, we cannot use it. */
1357                 pthread_mutex_unlock(&vstream->overwrite_lock);
1358                 ret = viewer_stream_rotate(vstream, rstream);
1359                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1360                 if (ret < 0) {
1361                         goto end_unlock;
1362                 } else if (ret == 1) {
1363                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1364                         viewer_stream_delete(vstream);
1365                         viewer_stream_destroy(ctf_trace, vstream);
1366                 } else {
1367                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1368                 }
1369                 goto send_reply;
1370         }
1371
1372         read_ret = lttng_read(vstream->index_read_fd, &packet_index,
1373                         sizeof(packet_index));
1374         pthread_mutex_unlock(&vstream->overwrite_lock);
1375         pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1376         if (read_ret < 0) {
1377                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1378                 viewer_stream_delete(vstream);
1379                 viewer_stream_destroy(ctf_trace, vstream);
1380                 goto send_reply;
1381         } else if (read_ret < sizeof(packet_index)) {
1382                 pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1383                 if (vstream->close_write_flag) {
1384                         ret = viewer_stream_rotate(vstream, rstream);
1385                         if (ret < 0) {
1386                                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1387                                 goto end_unlock;
1388                         } else if (ret == 1) {
1389                                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1390                                 viewer_stream_delete(vstream);
1391                                 viewer_stream_destroy(ctf_trace, vstream);
1392                         } else {
1393                                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1394                         }
1395                 } else {
1396                         ERR("Relay reading index file %d", vstream->index_read_fd);
1397                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1398                 }
1399                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1400                 goto send_reply;
1401         } else {
1402                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_OK);
1403                 vstream->last_sent_index++;
1404         }
1405
1406         /*
1407          * Indexes are stored in big endian, no need to switch before sending.
1408          */
1409         viewer_index.offset = packet_index.offset;
1410         viewer_index.packet_size = packet_index.packet_size;
1411         viewer_index.content_size = packet_index.content_size;
1412         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1413         viewer_index.timestamp_end = packet_index.timestamp_end;
1414         viewer_index.events_discarded = packet_index.events_discarded;
1415         viewer_index.stream_id = packet_index.stream_id;
1416
1417 send_reply:
1418         viewer_index.flags = htobe32(viewer_index.flags);
1419         health_code_update();
1420
1421         ret = send_response(conn->sock, &viewer_index, sizeof(viewer_index));
1422         if (ret < 0) {
1423                 goto end_unlock;
1424         }
1425         health_code_update();
1426
1427         DBG("Index %" PRIu64 " for stream %" PRIu64 " sent",
1428                         vstream->last_sent_index, vstream->stream_handle);
1429
1430 end_unlock:
1431         rcu_read_unlock();
1432
1433 end:
1434         return ret;
1435 }
1436
1437 /*
1438  * Send the next index for a stream
1439  *
1440  * Return 0 on success or else a negative value.
1441  */
1442 static
1443 int viewer_get_packet(struct relay_connection *conn)
1444 {
1445         int ret, send_data = 0;
1446         char *data = NULL;
1447         uint32_t len = 0;
1448         ssize_t read_len;
1449         struct lttng_viewer_get_packet get_packet_info;
1450         struct lttng_viewer_trace_packet reply;
1451         struct relay_viewer_stream *stream;
1452         struct relay_session *session;
1453         struct ctf_trace *ctf_trace;
1454
1455         assert(conn);
1456
1457         DBG2("Relay get data packet");
1458
1459         health_code_update();
1460
1461         ret = recv_request(conn->sock, &get_packet_info, sizeof(get_packet_info));
1462         if (ret < 0) {
1463                 goto end;
1464         }
1465         health_code_update();
1466
1467         /* From this point on, the error label can be reached. */
1468         memset(&reply, 0, sizeof(reply));
1469
1470         rcu_read_lock();
1471         stream = viewer_stream_find_by_id(be64toh(get_packet_info.stream_id));
1472         if (!stream) {
1473                 goto error;
1474         }
1475
1476         session = session_find_by_id(conn->sessions_ht, stream->session_id);
1477         if (!session) {
1478                 ret = -1;
1479                 goto error;
1480         }
1481
1482         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
1483                         stream->path_name);
1484         assert(ctf_trace);
1485
1486         /*
1487          * First time we read this stream, we need open the tracefile, we should
1488          * only arrive here if an index has already been sent to the viewer, so the
1489          * tracefile must exist, if it does not it is a fatal error.
1490          */
1491         if (stream->read_fd < 0) {
1492                 char fullpath[PATH_MAX];
1493
1494                 if (stream->tracefile_count > 0) {
1495                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64, stream->path_name,
1496                                         stream->channel_name,
1497                                         stream->tracefile_count_current);
1498                 } else {
1499                         ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1500                                         stream->channel_name);
1501                 }
1502                 if (ret < 0) {
1503                         goto error;
1504                 }
1505                 ret = open(fullpath, O_RDONLY);
1506                 if (ret < 0) {
1507                         PERROR("Relay opening trace file");
1508                         goto error;
1509                 }
1510                 stream->read_fd = ret;
1511         }
1512
1513         if (!ctf_trace->metadata_received ||
1514                         ctf_trace->metadata_received > ctf_trace->metadata_sent) {
1515                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1516                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1517                 goto send_reply;
1518         }
1519
1520         ret = check_new_streams(conn);
1521         if (ret < 0) {
1522                 goto end_unlock;
1523         } else if (ret == 1) {
1524                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1525                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1526                 goto send_reply;
1527         }
1528
1529         len = be32toh(get_packet_info.len);
1530         data = zmalloc(len);
1531         if (!data) {
1532                 PERROR("relay data zmalloc");
1533                 goto error;
1534         }
1535
1536         ret = lseek(stream->read_fd, be64toh(get_packet_info.offset), SEEK_SET);
1537         if (ret < 0) {
1538                 /*
1539                  * If the read fd was closed by the streaming side, the
1540                  * abort_flag will be set to 1, otherwise it is an error.
1541                  */
1542                 if (stream->abort_flag == 0) {
1543                         PERROR("lseek");
1544                         goto error;
1545                 }
1546                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_EOF);
1547                 goto send_reply;
1548         }
1549         read_len = lttng_read(stream->read_fd, data, len);
1550         if (read_len < len) {
1551                 /*
1552                  * If the read fd was closed by the streaming side, the
1553                  * abort_flag will be set to 1, otherwise it is an error.
1554                  */
1555                 if (stream->abort_flag == 0) {
1556                         PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1557                                         stream->read_fd,
1558                                         be64toh(get_packet_info.offset));
1559                         goto error;
1560                 } else {
1561                         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_EOF);
1562                         goto send_reply;
1563                 }
1564         }
1565         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_OK);
1566         reply.len = htobe32(len);
1567         send_data = 1;
1568         goto send_reply;
1569
1570 error:
1571         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1572
1573 send_reply:
1574         reply.flags = htobe32(reply.flags);
1575
1576         health_code_update();
1577
1578         ret = send_response(conn->sock, &reply, sizeof(reply));
1579         if (ret < 0) {
1580                 goto end_unlock;
1581         }
1582         health_code_update();
1583
1584         if (send_data) {
1585                 health_code_update();
1586                 ret = send_response(conn->sock, data, len);
1587                 if (ret < 0) {
1588                         goto end_unlock;
1589                 }
1590                 health_code_update();
1591         }
1592
1593         DBG("Sent %u bytes for stream %" PRIu64, len,
1594                         be64toh(get_packet_info.stream_id));
1595
1596 end_unlock:
1597         free(data);
1598         rcu_read_unlock();
1599
1600 end:
1601         return ret;
1602 }
1603
1604 /*
1605  * Send the session's metadata
1606  *
1607  * Return 0 on success else a negative value.
1608  */
1609 static
1610 int viewer_get_metadata(struct relay_connection *conn)
1611 {
1612         int ret = 0;
1613         ssize_t read_len;
1614         uint64_t len = 0;
1615         char *data = NULL;
1616         struct lttng_viewer_get_metadata request;
1617         struct lttng_viewer_metadata_packet reply;
1618         struct relay_viewer_stream *stream;
1619         struct ctf_trace *ctf_trace;
1620         struct relay_session *session;
1621
1622         assert(conn);
1623
1624         DBG("Relay get metadata");
1625
1626         health_code_update();
1627
1628         ret = recv_request(conn->sock, &request, sizeof(request));
1629         if (ret < 0) {
1630                 goto end;
1631         }
1632         health_code_update();
1633
1634         memset(&reply, 0, sizeof(reply));
1635
1636         rcu_read_lock();
1637         stream = viewer_stream_find_by_id(be64toh(request.stream_id));
1638         if (!stream || !stream->metadata_flag) {
1639                 ERR("Invalid metadata stream");
1640                 goto error;
1641         }
1642
1643         session = session_find_by_id(conn->sessions_ht, stream->session_id);
1644         if (!session) {
1645                 ret = -1;
1646                 goto error;
1647         }
1648
1649         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
1650                         stream->path_name);
1651         assert(ctf_trace);
1652         assert(ctf_trace->metadata_sent <= ctf_trace->metadata_received);
1653
1654         len = ctf_trace->metadata_received - ctf_trace->metadata_sent;
1655         if (len == 0) {
1656                 reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
1657                 goto send_reply;
1658         }
1659
1660         /* first time, we open the metadata file */
1661         if (stream->read_fd < 0) {
1662                 char fullpath[PATH_MAX];
1663
1664                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1665                                 stream->channel_name);
1666                 if (ret < 0) {
1667                         goto error;
1668                 }
1669                 ret = open(fullpath, O_RDONLY);
1670                 if (ret < 0) {
1671                         PERROR("Relay opening metadata file");
1672                         goto error;
1673                 }
1674                 stream->read_fd = ret;
1675         }
1676
1677         reply.len = htobe64(len);
1678         data = zmalloc(len);
1679         if (!data) {
1680                 PERROR("viewer metadata zmalloc");
1681                 goto error;
1682         }
1683
1684         read_len = lttng_read(stream->read_fd, data, len);
1685         if (read_len < len) {
1686                 PERROR("Relay reading metadata file");
1687                 goto error;
1688         }
1689         ctf_trace->metadata_sent += read_len;
1690         reply.status = htobe32(LTTNG_VIEWER_METADATA_OK);
1691         goto send_reply;
1692
1693 error:
1694         reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1695
1696 send_reply:
1697         health_code_update();
1698         ret = send_response(conn->sock, &reply, sizeof(reply));
1699         if (ret < 0) {
1700                 goto end_unlock;
1701         }
1702         health_code_update();
1703
1704         if (len > 0) {
1705                 ret = send_response(conn->sock, data, len);
1706                 if (ret < 0) {
1707                         goto end_unlock;
1708                 }
1709         }
1710
1711         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1712                         be64toh(request.stream_id));
1713
1714         DBG("Metadata sent");
1715
1716 end_unlock:
1717         free(data);
1718         rcu_read_unlock();
1719 end:
1720         return ret;
1721 }
1722
1723 /*
1724  * Create a viewer session.
1725  *
1726  * Return 0 on success or else a negative value.
1727  */
1728 static
1729 int viewer_create_session(struct relay_connection *conn)
1730 {
1731         int ret;
1732         struct lttng_viewer_create_session_response resp;
1733
1734         DBG("Viewer create session received");
1735
1736         memset(&resp, 0, sizeof(resp));
1737         resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_OK);
1738         conn->viewer_session = zmalloc(sizeof(*conn->viewer_session));
1739         if (!conn->viewer_session) {
1740                 ERR("Allocation viewer session");
1741                 resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_ERR);
1742                 goto send_reply;
1743         }
1744         CDS_INIT_LIST_HEAD(&conn->viewer_session->sessions_head);
1745
1746 send_reply:
1747         health_code_update();
1748         ret = send_response(conn->sock, &resp, sizeof(resp));
1749         if (ret < 0) {
1750                 goto end;
1751         }
1752         health_code_update();
1753         ret = 0;
1754
1755 end:
1756         return ret;
1757 }
1758
1759
1760 /*
1761  * live_relay_unknown_command: send -1 if received unknown command
1762  */
1763 static
1764 void live_relay_unknown_command(struct relay_connection *conn)
1765 {
1766         struct lttcomm_relayd_generic_reply reply;
1767
1768         memset(&reply, 0, sizeof(reply));
1769         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1770         (void) send_response(conn->sock, &reply, sizeof(reply));
1771 }
1772
1773 /*
1774  * Process the commands received on the control socket
1775  */
1776 static
1777 int process_control(struct lttng_viewer_cmd *recv_hdr,
1778                 struct relay_connection *conn)
1779 {
1780         int ret = 0;
1781         uint32_t msg_value;
1782
1783         assert(recv_hdr);
1784         assert(conn);
1785
1786         msg_value = be32toh(recv_hdr->cmd);
1787
1788         /*
1789          * Make sure we've done the version check before any command other then a
1790          * new client connection.
1791          */
1792         if (msg_value != LTTNG_VIEWER_CONNECT && !conn->version_check_done) {
1793                 ERR("Viewer conn value %" PRIu32 " before version check", msg_value);
1794                 ret = -1;
1795                 goto end;
1796         }
1797
1798         switch (msg_value) {
1799         case LTTNG_VIEWER_CONNECT:
1800                 ret = viewer_connect(conn);
1801                 break;
1802         case LTTNG_VIEWER_LIST_SESSIONS:
1803                 ret = viewer_list_sessions(conn);
1804                 break;
1805         case LTTNG_VIEWER_ATTACH_SESSION:
1806                 ret = viewer_attach_session(conn);
1807                 break;
1808         case LTTNG_VIEWER_GET_NEXT_INDEX:
1809                 ret = viewer_get_next_index(conn);
1810                 break;
1811         case LTTNG_VIEWER_GET_PACKET:
1812                 ret = viewer_get_packet(conn);
1813                 break;
1814         case LTTNG_VIEWER_GET_METADATA:
1815                 ret = viewer_get_metadata(conn);
1816                 break;
1817         case LTTNG_VIEWER_GET_NEW_STREAMS:
1818                 ret = viewer_get_new_streams(conn);
1819                 break;
1820         case LTTNG_VIEWER_CREATE_SESSION:
1821                 ret = viewer_create_session(conn);
1822                 break;
1823         default:
1824                 ERR("Received unknown viewer command (%u)", be32toh(recv_hdr->cmd));
1825                 live_relay_unknown_command(conn);
1826                 ret = -1;
1827                 goto end;
1828         }
1829
1830 end:
1831         return ret;
1832 }
1833
1834 static
1835 void cleanup_connection_pollfd(struct lttng_poll_event *events, int pollfd)
1836 {
1837         int ret;
1838
1839         assert(events);
1840
1841         (void) lttng_poll_del(events, pollfd);
1842
1843         ret = close(pollfd);
1844         if (ret < 0) {
1845                 ERR("Closing pollfd %d", pollfd);
1846         }
1847 }
1848
1849 /*
1850  * Delete and destroy a connection.
1851  *
1852  * RCU read side lock MUST be acquired.
1853  */
1854 static void destroy_connection(struct lttng_ht *relay_connections_ht,
1855                 struct relay_connection *conn)
1856 {
1857         struct relay_session *session, *tmp_session;
1858
1859         assert(relay_connections_ht);
1860         assert(conn);
1861
1862         connection_delete(relay_connections_ht, conn);
1863
1864         if (!conn->viewer_session) {
1865                 goto end;
1866         }
1867
1868         rcu_read_lock();
1869         cds_list_for_each_entry_safe(session, tmp_session,
1870                         &conn->viewer_session->sessions_head,
1871                         viewer_session_list) {
1872                 DBG("Cleaning connection of session ID %" PRIu64, session->id);
1873                 cleanup_session(conn, session);
1874         }
1875         rcu_read_unlock();
1876
1877 end:
1878         connection_destroy(conn);
1879 }
1880
1881 /*
1882  * This thread does the actual work
1883  */
1884 static
1885 void *thread_worker(void *data)
1886 {
1887         int ret, err = -1;
1888         uint32_t nb_fd;
1889         struct relay_connection *conn;
1890         struct lttng_poll_event events;
1891         struct lttng_ht *relay_connections_ht;
1892         struct lttng_ht_iter iter;
1893         struct lttng_viewer_cmd recv_hdr;
1894         struct relay_local_data *relay_ctx = (struct relay_local_data *) data;
1895         struct lttng_ht *sessions_ht = relay_ctx->sessions_ht;
1896
1897         DBG("[thread] Live viewer relay worker started");
1898
1899         rcu_register_thread();
1900
1901         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1902
1903         if (testpoint(relayd_thread_live_worker)) {
1904                 goto error_testpoint;
1905         }
1906
1907         /* table of connections indexed on socket */
1908         relay_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1909         if (!relay_connections_ht) {
1910                 goto relay_connections_ht_error;
1911         }
1912
1913         ret = create_thread_poll_set(&events, 2);
1914         if (ret < 0) {
1915                 goto error_poll_create;
1916         }
1917
1918         ret = lttng_poll_add(&events, live_conn_pipe[0], LPOLLIN | LPOLLRDHUP);
1919         if (ret < 0) {
1920                 goto error;
1921         }
1922
1923 restart:
1924         while (1) {
1925                 int i;
1926
1927                 health_code_update();
1928
1929                 /* Infinite blocking call, waiting for transmission */
1930                 DBG3("Relayd live viewer worker thread polling...");
1931                 health_poll_entry();
1932                 ret = lttng_poll_wait(&events, -1);
1933                 health_poll_exit();
1934                 if (ret < 0) {
1935                         /*
1936                          * Restart interrupted system call.
1937                          */
1938                         if (errno == EINTR) {
1939                                 goto restart;
1940                         }
1941                         goto error;
1942                 }
1943
1944                 nb_fd = ret;
1945
1946                 /*
1947                  * Process control. The control connection is prioritised so we don't
1948                  * starve it with high throughput tracing data on the data
1949                  * connection.
1950                  */
1951                 for (i = 0; i < nb_fd; i++) {
1952                         /* Fetch once the poll data */
1953                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1954                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1955
1956                         health_code_update();
1957
1958                         if (!revents) {
1959                                 /* No activity for this FD (poll implementation). */
1960                                 continue;
1961                         }
1962
1963                         /* Thread quit pipe has been closed. Killing thread. */
1964                         ret = check_thread_quit_pipe(pollfd, revents);
1965                         if (ret) {
1966                                 err = 0;
1967                                 goto exit;
1968                         }
1969
1970                         /* Inspect the relay conn pipe for new connection */
1971                         if (pollfd == live_conn_pipe[0]) {
1972                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1973                                         ERR("Relay live pipe error");
1974                                         goto error;
1975                                 } else if (revents & LPOLLIN) {
1976                                         ret = lttng_read(live_conn_pipe[0], &conn, sizeof(conn));
1977                                         if (ret < 0) {
1978                                                 goto error;
1979                                         }
1980                                         conn->sessions_ht = sessions_ht;
1981                                         connection_init(conn);
1982                                         lttng_poll_add(&events, conn->sock->fd,
1983                                                         LPOLLIN | LPOLLRDHUP);
1984                                         rcu_read_lock();
1985                                         lttng_ht_add_unique_ulong(relay_connections_ht,
1986                                                         &conn->sock_n);
1987                                         rcu_read_unlock();
1988                                         DBG("Connection socket %d added", conn->sock->fd);
1989                                 }
1990                         } else {
1991                                 rcu_read_lock();
1992                                 conn = connection_find_by_sock(relay_connections_ht, pollfd);
1993                                 /* If not found, there is a synchronization issue. */
1994                                 assert(conn);
1995
1996                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1997                                         cleanup_connection_pollfd(&events, pollfd);
1998                                         destroy_connection(relay_connections_ht, conn);
1999                                 } else if (revents & LPOLLIN) {
2000                                         ret = conn->sock->ops->recvmsg(conn->sock, &recv_hdr,
2001                                                         sizeof(recv_hdr), 0);
2002                                         if (ret <= 0) {
2003                                                 /* Connection closed */
2004                                                 cleanup_connection_pollfd(&events, pollfd);
2005                                                 destroy_connection(relay_connections_ht, conn);
2006                                                 DBG("Viewer control conn closed with %d", pollfd);
2007                                         } else {
2008                                                 ret = process_control(&recv_hdr, conn);
2009                                                 if (ret < 0) {
2010                                                         /* Clear the session on error. */
2011                                                         cleanup_connection_pollfd(&events, pollfd);
2012                                                         destroy_connection(relay_connections_ht, conn);
2013                                                         DBG("Viewer connection closed with %d", pollfd);
2014                                                 }
2015                                         }
2016                                 }
2017                                 rcu_read_unlock();
2018                         }
2019                 }
2020         }
2021
2022 exit:
2023 error:
2024         lttng_poll_clean(&events);
2025
2026         /* Cleanup reamaining connection object. */
2027         rcu_read_lock();
2028         cds_lfht_for_each_entry(relay_connections_ht->ht, &iter.iter, conn,
2029                         sock_n.node) {
2030                 health_code_update();
2031                 destroy_connection(relay_connections_ht, conn);
2032         }
2033         rcu_read_unlock();
2034 error_poll_create:
2035         lttng_ht_destroy(relay_connections_ht);
2036 relay_connections_ht_error:
2037         /* Close relay conn pipes */
2038         utils_close_pipe(live_conn_pipe);
2039         if (err) {
2040                 DBG("Viewer worker thread exited with error");
2041         }
2042         DBG("Viewer worker thread cleanup complete");
2043 error_testpoint:
2044         if (err) {
2045                 health_error();
2046                 ERR("Health error occurred in %s", __func__);
2047         }
2048         health_unregister(health_relayd);
2049         stop_threads();
2050         rcu_unregister_thread();
2051         return NULL;
2052 }
2053
2054 /*
2055  * Create the relay command pipe to wake thread_manage_apps.
2056  * Closed in cleanup().
2057  */
2058 static int create_conn_pipe(void)
2059 {
2060         int ret;
2061
2062         ret = utils_create_pipe_cloexec(live_conn_pipe);
2063
2064         return ret;
2065 }
2066
2067 void live_stop_threads(void)
2068 {
2069         int ret;
2070         void *status;
2071
2072         stop_threads();
2073
2074         ret = pthread_join(live_listener_thread, &status);
2075         if (ret != 0) {
2076                 PERROR("pthread_join live listener");
2077                 goto error;     /* join error, exit without cleanup */
2078         }
2079
2080         ret = pthread_join(live_worker_thread, &status);
2081         if (ret != 0) {
2082                 PERROR("pthread_join live worker");
2083                 goto error;     /* join error, exit without cleanup */
2084         }
2085
2086         ret = pthread_join(live_dispatcher_thread, &status);
2087         if (ret != 0) {
2088                 PERROR("pthread_join live dispatcher");
2089                 goto error;     /* join error, exit without cleanup */
2090         }
2091
2092         cleanup();
2093
2094 error:
2095         return;
2096 }
2097
2098 /*
2099  * main
2100  */
2101 int live_start_threads(struct lttng_uri *uri,
2102                 struct relay_local_data *relay_ctx)
2103 {
2104         int ret = 0;
2105         void *status;
2106         int is_root;
2107
2108         assert(uri);
2109         live_uri = uri;
2110
2111         /* Check if daemon is UID = 0 */
2112         is_root = !getuid();
2113
2114         if (!is_root) {
2115                 if (live_uri->port < 1024) {
2116                         ERR("Need to be root to use ports < 1024");
2117                         ret = -1;
2118                         goto exit;
2119                 }
2120         }
2121
2122         /* Setup the thread apps communication pipe. */
2123         if ((ret = create_conn_pipe()) < 0) {
2124                 goto exit;
2125         }
2126
2127         /* Init relay command queue. */
2128         cds_wfcq_init(&viewer_conn_queue.head, &viewer_conn_queue.tail);
2129
2130         /* Set up max poll set size */
2131         lttng_poll_set_max_size();
2132
2133         /* Setup the dispatcher thread */
2134         ret = pthread_create(&live_dispatcher_thread, NULL,
2135                         thread_dispatcher, (void *) NULL);
2136         if (ret != 0) {
2137                 PERROR("pthread_create viewer dispatcher");
2138                 goto exit_dispatcher;
2139         }
2140
2141         /* Setup the worker thread */
2142         ret = pthread_create(&live_worker_thread, NULL,
2143                         thread_worker, relay_ctx);
2144         if (ret != 0) {
2145                 PERROR("pthread_create viewer worker");
2146                 goto exit_worker;
2147         }
2148
2149         /* Setup the listener thread */
2150         ret = pthread_create(&live_listener_thread, NULL,
2151                         thread_listener, (void *) NULL);
2152         if (ret != 0) {
2153                 PERROR("pthread_create viewer listener");
2154                 goto exit_listener;
2155         }
2156
2157         ret = 0;
2158         goto end;
2159
2160 exit_listener:
2161         ret = pthread_join(live_listener_thread, &status);
2162         if (ret != 0) {
2163                 PERROR("pthread_join live listener");
2164                 goto error;     /* join error, exit without cleanup */
2165         }
2166
2167 exit_worker:
2168         ret = pthread_join(live_worker_thread, &status);
2169         if (ret != 0) {
2170                 PERROR("pthread_join live worker");
2171                 goto error;     /* join error, exit without cleanup */
2172         }
2173
2174 exit_dispatcher:
2175         ret = pthread_join(live_dispatcher_thread, &status);
2176         if (ret != 0) {
2177                 PERROR("pthread_join live dispatcher");
2178                 goto error;     /* join error, exit without cleanup */
2179         }
2180
2181 exit:
2182         cleanup();
2183
2184 end:
2185 error:
2186         return ret;
2187 }