src/bin/lttng-relayd/live.c

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