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, bool *closed)
 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         if (session->connection_closed) {
 285                 *closed = true;
 286         }
 287
 288         /*
 289          * Create viewer streams for relay streams that are ready to be
 290          * used for a the given session id only.
 291          */
 292         rcu_read_lock();
 293         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 294                         node.node) {
 295                 struct relay_stream *stream;
 296
 297                 health_code_update();
 298
 299                 if (!ctf_trace_get(ctf_trace)) {
 300                         continue;
 301                 }
 302
 303                 cds_list_for_each_entry_rcu(stream, &ctf_trace->stream_list, stream_node) {
 304                         struct relay_viewer_stream *vstream;
 305
 306                         if (!stream_get(stream)) {
 307                                 continue;
 308                         }
 309                         /*
 310                          * stream published is protected by the session lock.
 311                          */
 312                         if (!stream->published) {
 313                                 goto next;
 314                         }
 315                         vstream = viewer_stream_get_by_id(stream->stream_handle);
 316                         if (!vstream) {
 317                                 vstream = viewer_stream_create(stream, seek_t);
 318                                 if (!vstream) {
 319                                         ret = -1;
 320                                         ctf_trace_put(ctf_trace);
 321                                         stream_put(stream);
 322                                         goto error_unlock;
 323                                 }
 324
 325                                 if (nb_created) {
 326                                         /* Update number of created stream counter. */
 327                                         (*nb_created)++;
 328                                 }
 329                                 /*
 330                                  * Ensure a self-reference is preserved even
 331                                  * after we have put our local reference.
 332                                  */
 333                                 viewer_stream_get(vstream);
 334                         } else {
 335                                 if (!vstream->sent_flag && nb_unsent) {
 336                                         /* Update number of unsent stream counter. */
 337                                         (*nb_unsent)++;
 338                                 }
 339                         }
 340                         /* Update number of total stream counter. */
 341                         if (nb_total) {
 342                                 if (stream->is_metadata) {
 343                                         if (!stream->closed ||
 344                                                         stream->metadata_received > vstream->metadata_sent) {
 345                                                 (*nb_total)++;
 346                                         }
 347                                 } else {
 348                                         if (!stream->closed ||
 349                                                 !(((int64_t) (stream->prev_seq - stream->last_net_seq_num)) >= 0)) {
 350
 351                                                 (*nb_total)++;
 352                                         }
 353                                 }
 354                         }
 355                         /* Put local reference. */
 356                         viewer_stream_put(vstream);
 357                 next:
 358                         stream_put(stream);
 359                 }
 360                 ctf_trace_put(ctf_trace);
 361         }
 362
 363         ret = 0;
 364
 365 error_unlock:
 366         rcu_read_unlock();
 367         pthread_mutex_unlock(&session->lock);
 368         return ret;
 369 }
 370
 371 int relayd_live_stop(void)
 372 {
 373         /* Stop dispatch thread */
 374         CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
 375         futex_nto1_wake(&viewer_conn_queue.futex);
 376         return 0;
 377 }
 378
 379 /*
 380  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 381  */
 382 static
 383 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 384 {
 385         int ret;
 386
 387         if (events == NULL || size == 0) {
 388                 ret = -1;
 389                 goto error;
 390         }
 391
 392         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 393         if (ret < 0) {
 394                 goto error;
 395         }
 396
 397         /* Add quit pipe */
 398         ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
 399         if (ret < 0) {
 400                 goto error;
 401         }
 402
 403         return 0;
 404
 405 error:
 406         return ret;
 407 }
 408
 409 /*
 410  * Check if the thread quit pipe was triggered.
 411  *
 412  * Return 1 if it was triggered else 0;
 413  */
 414 static
 415 int check_thread_quit_pipe(int fd, uint32_t events)
 416 {
 417         if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
 418                 return 1;
 419         }
 420
 421         return 0;
 422 }
 423
 424 /*
 425  * Create and init socket from uri.
 426  */
 427 static
 428 struct lttcomm_sock *init_socket(struct lttng_uri *uri)
 429 {
 430         int ret;
 431         struct lttcomm_sock *sock = NULL;
 432
 433         sock = lttcomm_alloc_sock_from_uri(uri);
 434         if (sock == NULL) {
 435                 ERR("Allocating socket");
 436                 goto error;
 437         }
 438
 439         ret = lttcomm_create_sock(sock);
 440         if (ret < 0) {
 441                 goto error;
 442         }
 443         DBG("Listening on sock %d for live", sock->fd);
 444
 445         ret = sock->ops->bind(sock);
 446         if (ret < 0) {
 447                 goto error;
 448         }
 449
 450         ret = sock->ops->listen(sock, -1);
 451         if (ret < 0) {
 452                 goto error;
 453
 454         }
 455
 456         return sock;
 457
 458 error:
 459         if (sock) {
 460                 lttcomm_destroy_sock(sock);
 461         }
 462         return NULL;
 463 }
 464
 465 /*
 466  * This thread manages the listening for new connections on the network
 467  */
 468 static
 469 void *thread_listener(void *data)
 470 {
 471         int i, ret, pollfd, err = -1;
 472         uint32_t revents, nb_fd;
 473         struct lttng_poll_event events;
 474         struct lttcomm_sock *live_control_sock;
 475
 476         DBG("[thread] Relay live listener started");
 477
 478         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_LISTENER);
 479
 480         health_code_update();
 481
 482         live_control_sock = init_socket(live_uri);
 483         if (!live_control_sock) {
 484                 goto error_sock_control;
 485         }
 486
 487         /* Pass 2 as size here for the thread quit pipe and control sockets. */
 488         ret = create_thread_poll_set(&events, 2);
 489         if (ret < 0) {
 490                 goto error_create_poll;
 491         }
 492
 493         /* Add the control socket */
 494         ret = lttng_poll_add(&events, live_control_sock->fd, LPOLLIN | LPOLLRDHUP);
 495         if (ret < 0) {
 496                 goto error_poll_add;
 497         }
 498
 499         lttng_relay_notify_ready();
 500
 501         if (testpoint(relayd_thread_live_listener)) {
 502                 goto error_testpoint;
 503         }
 504
 505         while (1) {
 506                 health_code_update();
 507
 508                 DBG("Listener accepting live viewers connections");
 509
 510 restart:
 511                 health_poll_entry();
 512                 ret = lttng_poll_wait(&events, -1);
 513                 health_poll_exit();
 514                 if (ret < 0) {
 515                         /*
 516                          * Restart interrupted system call.
 517                          */
 518                         if (errno == EINTR) {
 519                                 goto restart;
 520                         }
 521                         goto error;
 522                 }
 523                 nb_fd = ret;
 524
 525                 DBG("Relay new viewer connection received");
 526                 for (i = 0; i < nb_fd; i++) {
 527                         health_code_update();
 528
 529                         /* Fetch once the poll data */
 530                         revents = LTTNG_POLL_GETEV(&events, i);
 531                         pollfd = LTTNG_POLL_GETFD(&events, i);
 532
 533                         if (!revents) {
 534                                 /* No activity for this FD (poll implementation). */
 535                                 continue;
 536                         }
 537
 538                         /* Thread quit pipe has been closed. Killing thread. */
 539                         ret = check_thread_quit_pipe(pollfd, revents);
 540                         if (ret) {
 541                                 err = 0;
 542                                 goto exit;
 543                         }
 544
 545                         if (revents & LPOLLIN) {
 546                                 /*
 547                                  * A new connection is requested, therefore a
 548                                  * viewer connection is allocated in this
 549                                  * thread, enqueued to a global queue and
 550                                  * dequeued (and freed) in the worker thread.
 551                                  */
 552                                 int val = 1;
 553                                 struct relay_connection *new_conn;
 554                                 struct lttcomm_sock *newsock;
 555
 556                                 newsock = live_control_sock->ops->accept(live_control_sock);
 557                                 if (!newsock) {
 558                                         PERROR("accepting control sock");
 559                                         goto error;
 560                                 }
 561                                 DBG("Relay viewer connection accepted socket %d", newsock->fd);
 562
 563                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR, &val,
 564                                                 sizeof(val));
 565                                 if (ret < 0) {
 566                                         PERROR("setsockopt inet");
 567                                         lttcomm_destroy_sock(newsock);
 568                                         goto error;
 569                                 }
 570                                 new_conn = connection_create(newsock, RELAY_CONNECTION_UNKNOWN);
 571                                 if (!new_conn) {
 572                                         lttcomm_destroy_sock(newsock);
 573                                         goto error;
 574                                 }
 575                                 /* Ownership assumed by the connection. */
 576                                 newsock = NULL;
 577
 578                                 /* Enqueue request for the dispatcher thread. */
 579                                 cds_wfcq_enqueue(&viewer_conn_queue.head, &viewer_conn_queue.tail,
 580                                                  &new_conn->qnode);
 581
 582                                 /*
 583                                  * Wake the dispatch queue futex.
 584                                  * Implicit memory barrier with the
 585                                  * exchange in cds_wfcq_enqueue.
 586                                  */
 587                                 futex_nto1_wake(&viewer_conn_queue.futex);
 588                         } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 589                                 ERR("socket poll error");
 590                                 goto error;
 591                         } else {
 592                                 ERR("Unexpected poll events %u for sock %d", revents, pollfd);
 593                                 goto error;
 594                         }
 595                 }
 596         }
 597
 598 exit:
 599 error:
 600 error_poll_add:
 601 error_testpoint:
 602         lttng_poll_clean(&events);
 603 error_create_poll:
 604         if (live_control_sock->fd >= 0) {
 605                 ret = live_control_sock->ops->close(live_control_sock);
 606                 if (ret) {
 607                         PERROR("close");
 608                 }
 609         }
 610         lttcomm_destroy_sock(live_control_sock);
 611 error_sock_control:
 612         if (err) {
 613                 health_error();
 614                 DBG("Live viewer listener thread exited with error");
 615         }
 616         health_unregister(health_relayd);
 617         DBG("Live viewer listener thread cleanup complete");
 618         if (lttng_relay_stop_threads()) {
 619                 ERR("Error stopping threads");
 620         }
 621         return NULL;
 622 }
 623
 624 /*
 625  * This thread manages the dispatching of the requests to worker threads
 626  */
 627 static
 628 void *thread_dispatcher(void *data)
 629 {
 630         int err = -1;
 631         ssize_t ret;
 632         struct cds_wfcq_node *node;
 633         struct relay_connection *conn = NULL;
 634
 635         DBG("[thread] Live viewer relay dispatcher started");
 636
 637         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 638
 639         if (testpoint(relayd_thread_live_dispatcher)) {
 640                 goto error_testpoint;
 641         }
 642
 643         health_code_update();
 644
 645         while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 646                 health_code_update();
 647
 648                 /* Atomically prepare the queue futex */
 649                 futex_nto1_prepare(&viewer_conn_queue.futex);
 650
 651                 do {
 652                         health_code_update();
 653
 654                         /* Dequeue commands */
 655                         node = cds_wfcq_dequeue_blocking(&viewer_conn_queue.head,
 656                                                          &viewer_conn_queue.tail);
 657                         if (node == NULL) {
 658                                 DBG("Woken up but nothing in the live-viewer "
 659                                                 "relay command queue");
 660                                 /* Continue thread execution */
 661                                 break;
 662                         }
 663                         conn = caa_container_of(node, struct relay_connection, qnode);
 664                         DBG("Dispatching viewer request waiting on sock %d",
 665                                         conn->sock->fd);
 666
 667                         /*
 668                          * Inform worker thread of the new request. This
 669                          * call is blocking so we can be assured that
 670                          * the data will be read at some point in time
 671                          * or wait to the end of the world :)
 672                          */
 673                         ret = lttng_write(live_conn_pipe[1], &conn, sizeof(conn));
 674                         if (ret < 0) {
 675                                 PERROR("write conn pipe");
 676                                 connection_put(conn);
 677                                 goto error;
 678                         }
 679                 } while (node != NULL);
 680
 681                 /* Futex wait on queue. Blocking call on futex() */
 682                 health_poll_entry();
 683                 futex_nto1_wait(&viewer_conn_queue.futex);
 684                 health_poll_exit();
 685         }
 686
 687         /* Normal exit, no error */
 688         err = 0;
 689
 690 error:
 691 error_testpoint:
 692         if (err) {
 693                 health_error();
 694                 ERR("Health error occurred in %s", __func__);
 695         }
 696         health_unregister(health_relayd);
 697         DBG("Live viewer dispatch thread dying");
 698         if (lttng_relay_stop_threads()) {
 699                 ERR("Error stopping threads");
 700         }
 701         return NULL;
 702 }
 703
 704 /*
 705  * Establish connection with the viewer and check the versions.
 706  *
 707  * Return 0 on success or else negative value.
 708  */
 709 static
 710 int viewer_connect(struct relay_connection *conn)
 711 {
 712         int ret;
 713         struct lttng_viewer_connect reply, msg;
 714
 715         conn->version_check_done = 1;
 716
 717         health_code_update();
 718
 719         DBG("Viewer is establishing a connection to the relayd.");
 720
 721         ret = recv_request(conn->sock, &msg, sizeof(msg));
 722         if (ret < 0) {
 723                 goto end;
 724         }
 725
 726         health_code_update();
 727
 728         memset(&reply, 0, sizeof(reply));
 729         reply.major = RELAYD_VERSION_COMM_MAJOR;
 730         reply.minor = RELAYD_VERSION_COMM_MINOR;
 731
 732         /* Major versions must be the same */
 733         if (reply.major != be32toh(msg.major)) {
 734                 DBG("Incompatible major versions ([relayd] %u vs [client] %u)",
 735                                 reply.major, be32toh(msg.major));
 736                 ret = -1;
 737                 goto end;
 738         }
 739
 740         conn->major = reply.major;
 741         /* We adapt to the lowest compatible version */
 742         if (reply.minor <= be32toh(msg.minor)) {
 743                 conn->minor = reply.minor;
 744         } else {
 745                 conn->minor = be32toh(msg.minor);
 746         }
 747
 748         if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_COMMAND) {
 749                 conn->type = RELAY_VIEWER_COMMAND;
 750         } else if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_NOTIFICATION) {
 751                 conn->type = RELAY_VIEWER_NOTIFICATION;
 752         } else {
 753                 ERR("Unknown connection type : %u", be32toh(msg.type));
 754                 ret = -1;
 755                 goto end;
 756         }
 757
 758         reply.major = htobe32(reply.major);
 759         reply.minor = htobe32(reply.minor);
 760         if (conn->type == RELAY_VIEWER_COMMAND) {
 761                 /*
 762                  * Increment outside of htobe64 macro, because the argument can
 763                  * be used more than once within the macro, and thus the
 764                  * operation may be undefined.
 765                  */
 766                 pthread_mutex_lock(&last_relay_viewer_session_id_lock);
 767                 last_relay_viewer_session_id++;
 768                 pthread_mutex_unlock(&last_relay_viewer_session_id_lock);
 769                 reply.viewer_session_id = htobe64(last_relay_viewer_session_id);
 770         }
 771
 772         health_code_update();
 773
 774         ret = send_response(conn->sock, &reply, sizeof(reply));
 775         if (ret < 0) {
 776                 goto end;
 777         }
 778
 779         health_code_update();
 780
 781         DBG("Version check done using protocol %u.%u", conn->major, conn->minor);
 782         ret = 0;
 783
 784 end:
 785         return ret;
 786 }
 787
 788 /*
 789  * Send the viewer the list of current sessions.
 790  * We need to create a copy of the hash table content because otherwise
 791  * we cannot assume the number of entries stays the same between getting
 792  * the number of HT elements and iteration over the HT.
 793  *
 794  * Return 0 on success or else a negative value.
 795  */
 796 static
 797 int viewer_list_sessions(struct relay_connection *conn)
 798 {
 799         int ret;
 800         struct lttng_viewer_list_sessions session_list;
 801         struct lttng_ht_iter iter;
 802         struct relay_session *session;
 803         struct lttng_viewer_session *send_session_buf = NULL;
 804         uint32_t buf_count = SESSION_BUF_DEFAULT_COUNT;
 805         uint32_t count = 0;
 806
 807         DBG("List sessions received");
 808
 809         send_session_buf = zmalloc(SESSION_BUF_DEFAULT_COUNT * sizeof(*send_session_buf));
 810         if (!send_session_buf) {
 811                 return -1;
 812         }
 813
 814         rcu_read_lock();
 815         cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
 816                         session_n.node) {
 817                 struct lttng_viewer_session *send_session;
 818
 819                 health_code_update();
 820
 821                 if (count >= buf_count) {
 822                         struct lttng_viewer_session *newbuf;
 823                         uint32_t new_buf_count = buf_count << 1;
 824
 825                         newbuf = realloc(send_session_buf,
 826                                 new_buf_count * sizeof(*send_session_buf));
 827                         if (!newbuf) {
 828                                 ret = -1;
 829                                 rcu_read_unlock();
 830                                 goto end_free;
 831                         }
 832                         send_session_buf = newbuf;
 833                         buf_count = new_buf_count;
 834                 }
 835                 send_session = &send_session_buf[count];
 836                 strncpy(send_session->session_name, session->session_name,
 837                                 sizeof(send_session->session_name));
 838                 strncpy(send_session->hostname, session->hostname,
 839                                 sizeof(send_session->hostname));
 840                 send_session->id = htobe64(session->id);
 841                 send_session->live_timer = htobe32(session->live_timer);
 842                 if (session->viewer_attached) {
 843                         send_session->clients = htobe32(1);
 844                 } else {
 845                         send_session->clients = htobe32(0);
 846                 }
 847                 send_session->streams = htobe32(session->stream_count);
 848                 count++;
 849         }
 850         rcu_read_unlock();
 851
 852         session_list.sessions_count = htobe32(count);
 853
 854         health_code_update();
 855
 856         ret = send_response(conn->sock, &session_list, sizeof(session_list));
 857         if (ret < 0) {
 858                 goto end_free;
 859         }
 860
 861         health_code_update();
 862
 863         ret = send_response(conn->sock, send_session_buf,
 864                         count * sizeof(*send_session_buf));
 865         if (ret < 0) {
 866                 goto end_free;
 867         }
 868         health_code_update();
 869
 870         ret = 0;
 871 end_free:
 872         free(send_session_buf);
 873         return ret;
 874 }
 875
 876 /*
 877  * Send the viewer the list of current streams.
 878  */
 879 static
 880 int viewer_get_new_streams(struct relay_connection *conn)
 881 {
 882         int ret, send_streams = 0;
 883         uint32_t nb_created = 0, nb_unsent = 0, nb_streams = 0, nb_total = 0;
 884         struct lttng_viewer_new_streams_request request;
 885         struct lttng_viewer_new_streams_response response;
 886         struct relay_session *session;
 887         uint64_t session_id;
 888         bool closed = false;
 889
 890         assert(conn);
 891
 892         DBG("Get new streams received");
 893
 894         health_code_update();
 895
 896         /* Receive the request from the connected client. */
 897         ret = recv_request(conn->sock, &request, sizeof(request));
 898         if (ret < 0) {
 899                 goto error;
 900         }
 901         session_id = be64toh(request.session_id);
 902
 903         health_code_update();
 904
 905         memset(&response, 0, sizeof(response));
 906
 907         session = session_get_by_id(session_id);
 908         if (!session) {
 909                 DBG("Relay session %" PRIu64 " not found", session_id);
 910                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 911                 goto send_reply;
 912         }
 913
 914         if (!viewer_session_is_attached(conn->viewer_session, session)) {
 915                 send_streams = 0;
 916                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 917                 goto send_reply;
 918         }
 919
 920         send_streams = 1;
 921         response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 922
 923         ret = make_viewer_streams(session, LTTNG_VIEWER_SEEK_LAST, &nb_total, &nb_unsent,
 924                         &nb_created, &closed);
 925         if (ret < 0) {
 926                 goto end_put_session;
 927         }
 928         /* Only send back the newly created streams with the unsent ones. */
 929         nb_streams = nb_created + nb_unsent;
 930         response.streams_count = htobe32(nb_streams);
 931
 932         /*
 933          * If the session is closed, HUP when there are no more streams
 934          * with data.
 935          */
 936         if (closed && nb_total == 0) {
 937                 send_streams = 0;
 938                 response.streams_count = 0;
 939                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
 940                 goto send_reply;
 941         }
 942
 943 send_reply:
 944         health_code_update();
 945         ret = send_response(conn->sock, &response, sizeof(response));
 946         if (ret < 0) {
 947                 goto end_put_session;
 948         }
 949         health_code_update();
 950
 951         /*
 952          * Unknown or empty session, just return gracefully, the viewer
 953          * knows what is happening.
 954          */
 955         if (!send_streams || !nb_streams) {
 956                 ret = 0;
 957                 goto end_put_session;
 958         }
 959
 960         /*
 961          * Send stream and *DON'T* ignore the sent flag so every viewer
 962          * streams that were not sent from that point will be sent to
 963          * the viewer.
 964          */
 965         ret = send_viewer_streams(conn->sock, session, 0);
 966         if (ret < 0) {
 967                 goto end_put_session;
 968         }
 969
 970 end_put_session:
 971         if (session) {
 972                 session_put(session);
 973         }
 974 error:
 975         return ret;
 976 }
 977
 978 /*
 979  * Send the viewer the list of current sessions.
 980  */
 981 static
 982 int viewer_attach_session(struct relay_connection *conn)
 983 {
 984         int send_streams = 0;
 985         ssize_t ret;
 986         uint32_t nb_streams = 0;
 987         enum lttng_viewer_seek seek_type;
 988         struct lttng_viewer_attach_session_request request;
 989         struct lttng_viewer_attach_session_response response;
 990         struct relay_session *session = NULL;
 991         bool closed = false;
 992
 993         assert(conn);
 994
 995         health_code_update();
 996
 997         /* Receive the request from the connected client. */
 998         ret = recv_request(conn->sock, &request, sizeof(request));
 999         if (ret < 0) {
1000                 goto error;
1001         }
1002
1003         health_code_update();
1004
1005         memset(&response, 0, sizeof(response));
1006
1007         if (!conn->viewer_session) {
1008                 DBG("Client trying to attach before creating a live viewer session");
1009                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NO_SESSION);
1010                 goto send_reply;
1011         }
1012
1013         session = session_get_by_id(be64toh(request.session_id));
1014         if (!session) {
1015                 DBG("Relay session %" PRIu64 " not found",
1016                                 be64toh(request.session_id));
1017                 response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
1018                 goto send_reply;
1019         }
1020         DBG("Attach session ID %" PRIu64 " received",
1021                 be64toh(request.session_id));
1022
1023         if (session->live_timer == 0) {
1024                 DBG("Not live session");
1025                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NOT_LIVE);
1026                 goto send_reply;
1027         }
1028
1029         send_streams = 1;
1030         ret = viewer_session_attach(conn->viewer_session, session);
1031         if (ret) {
1032                 DBG("Already a viewer attached");
1033                 response.status = htobe32(LTTNG_VIEWER_ATTACH_ALREADY);
1034                 goto send_reply;
1035         }
1036
1037         switch (be32toh(request.seek)) {
1038         case LTTNG_VIEWER_SEEK_BEGINNING:
1039         case LTTNG_VIEWER_SEEK_LAST:
1040                 response.status = htobe32(LTTNG_VIEWER_ATTACH_OK);
1041                 seek_type = be32toh(request.seek);
1042                 break;
1043         default:
1044                 ERR("Wrong seek parameter");
1045                 response.status = htobe32(LTTNG_VIEWER_ATTACH_SEEK_ERR);
1046                 send_streams = 0;
1047                 goto send_reply;
1048         }
1049
1050         ret = make_viewer_streams(session, seek_type, &nb_streams, NULL,
1051                         NULL, &closed);
1052         if (ret < 0) {
1053                 goto end_put_session;
1054         }
1055         response.streams_count = htobe32(nb_streams);
1056
1057         /*
1058          * If the session is closed when the viewer is attaching, it
1059          * means some of the streams may have been concurrently removed,
1060          * so we don't allow the viewer to attach, even if there are
1061          * streams available.
1062          */
1063         if (closed) {
1064                 send_streams = 0;
1065                 response.streams_count = 0;
1066                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
1067                 goto send_reply;
1068         }
1069
1070 send_reply:
1071         health_code_update();
1072         ret = send_response(conn->sock, &response, sizeof(response));
1073         if (ret < 0) {
1074                 goto end_put_session;
1075         }
1076         health_code_update();
1077
1078         /*
1079          * Unknown or empty session, just return gracefully, the viewer
1080          * knows what is happening.
1081          */
1082         if (!send_streams || !nb_streams) {
1083                 ret = 0;
1084                 goto end_put_session;
1085         }
1086
1087         /* Send stream and ignore the sent flag. */
1088         ret = send_viewer_streams(conn->sock, session, 1);
1089         if (ret < 0) {
1090                 goto end_put_session;
1091         }
1092
1093 end_put_session:
1094         if (session) {
1095                 session_put(session);
1096         }
1097 error:
1098         return ret;
1099 }
1100
1101 /*
1102  * Open the index file if needed for the given vstream.
1103  *
1104  * If an index file is successfully opened, the vstream index_fd set with
1105  * it.
1106  *
1107  * Return 0 on success, a negative value on error (-ENOENT if not ready yet).
1108  *
1109  * Called with rstream lock held.
1110  */
1111 static int try_open_index(struct relay_viewer_stream *vstream,
1112                 struct relay_stream *rstream)
1113 {
1114         int ret = 0;
1115
1116         if (vstream->index_fd) {
1117                 goto end;
1118         }
1119
1120         /*
1121          * First time, we open the index file and at least one index is ready.
1122          */
1123         if (rstream->index_received_seqcount == 0) {
1124                 ret = -ENOENT;
1125                 goto end;
1126         }
1127         ret = index_open(vstream->path_name, vstream->channel_name,
1128                         vstream->stream->tracefile_count,
1129                         vstream->current_tracefile_id);
1130         if (ret >= 0) {
1131                 vstream->index_fd = stream_fd_create(ret);
1132                 if (!vstream->index_fd) {
1133                         if (close(ret)) {
1134                                 PERROR("close");
1135                         }
1136                         ret = -1;
1137                 } else {
1138                         ret = 0;
1139                 }
1140                 goto end;
1141         }
1142
1143 end:
1144         return ret;
1145 }
1146
1147 /*
1148  * Check the status of the index for the given stream. This function
1149  * updates the index structure if needed and can put (close) the vstream
1150  * in the HUP situation.
1151  *
1152  * Return 0 means that we can proceed with the index. A value of 1 means
1153  * that the index has been updated and is ready to be sent to the
1154  * client. A negative value indicates an error that can't be handled.
1155  *
1156  * Called with rstream lock held.
1157  */
1158 static int check_index_status(struct relay_viewer_stream *vstream,
1159                 struct relay_stream *rstream, struct ctf_trace *trace,
1160                 struct lttng_viewer_index *index)
1161 {
1162         int ret;
1163
1164         if (trace->session->connection_closed
1165                         && rstream->index_received_seqcount
1166                                 == vstream->index_sent_seqcount) {
1167                 /* Last index sent and session connection is closed. */
1168                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1169                 goto hup;
1170         } else if (rstream->beacon_ts_end != -1ULL &&
1171                         rstream->index_received_seqcount
1172                                 == vstream->index_sent_seqcount) {
1173                 /*
1174                  * We've received a synchronization beacon and the last index
1175                  * available has been sent, the index for now is inactive.
1176                  *
1177                  * In this case, we have received a beacon which allows us to
1178                  * inform the client of a time interval during which we can
1179                  * guarantee that there are no events to read (and never will
1180                  * be).
1181                  */
1182                 index->status = htobe32(LTTNG_VIEWER_INDEX_INACTIVE);
1183                 index->timestamp_end = htobe64(rstream->beacon_ts_end);
1184                 index->stream_id = htobe64(rstream->ctf_stream_id);
1185                 goto index_ready;
1186         } else if (rstream->index_received_seqcount
1187                         == vstream->index_sent_seqcount) {
1188                 /*
1189                  * This checks whether received == sent seqcount. In
1190                  * this case, we have not received a beacon. Therefore,
1191                  * we can only ask the client to retry later.
1192                  */
1193                 index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1194                 goto index_ready;
1195         } else if (!tracefile_array_seq_in_file(rstream->tfa,
1196                         vstream->current_tracefile_id,
1197                         vstream->index_sent_seqcount)) {
1198                 /*
1199                  * The next index we want to send cannot be read either
1200                  * because we need to perform a rotation, or due to
1201                  * the producer having overwritten its trace file.
1202                  */
1203                 DBG("Viewer stream %" PRIu64 " rotation",
1204                                 vstream->stream->stream_handle);
1205                 ret = viewer_stream_rotate(vstream);
1206                 if (ret < 0) {
1207                         goto end;
1208                 } else if (ret == 1) {
1209                         /* EOF across entire stream. */
1210                         index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1211                         goto hup;
1212                 }
1213                 /*
1214                  * If we have been pushed due to overwrite, it
1215                  * necessarily means there is data that can be read in
1216                  * the stream. If we rotated because we reached the end
1217                  * of a tracefile, it means the following tracefile
1218                  * needs to contain at least one index, else we would
1219                  * have already returned LTTNG_VIEWER_INDEX_RETRY to the
1220                  * viewer. The updated index_sent_seqcount needs to
1221                  * point to a readable index entry now.
1222                  *
1223                  * In the case where we "rotate" on a single file, we
1224                  * can end up in a case where the requested index is
1225                  * still unavailable.
1226                  */
1227                 if (rstream->tracefile_count == 1 &&
1228                                 !tracefile_array_seq_in_file(
1229                                         rstream->tfa,
1230                                         vstream->current_tracefile_id,
1231                                         vstream->index_sent_seqcount)) {
1232                         index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1233                         goto index_ready;
1234                 }
1235                 assert(tracefile_array_seq_in_file(rstream->tfa,
1236                                 vstream->current_tracefile_id,
1237                                 vstream->index_sent_seqcount));
1238         }
1239         /* ret == 0 means successful so we continue. */
1240         ret = 0;
1241 end:
1242         return ret;
1243
1244 hup:
1245         viewer_stream_put(vstream);
1246 index_ready:
1247         return 1;
1248 }
1249
1250 /*
1251  * Send the next index for a stream.
1252  *
1253  * Return 0 on success or else a negative value.
1254  */
1255 static
1256 int viewer_get_next_index(struct relay_connection *conn)
1257 {
1258         int ret;
1259         ssize_t read_ret;
1260         struct lttng_viewer_get_next_index request_index;
1261         struct lttng_viewer_index viewer_index;
1262         struct ctf_packet_index packet_index;
1263         struct relay_viewer_stream *vstream = NULL;
1264         struct relay_stream *rstream = NULL;
1265         struct ctf_trace *ctf_trace = NULL;
1266         struct relay_viewer_stream *metadata_viewer_stream = NULL;
1267
1268         assert(conn);
1269
1270         DBG("Viewer get next index");
1271
1272         memset(&viewer_index, 0, sizeof(viewer_index));
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         vstream = viewer_stream_get_by_id(be64toh(request_index.stream_id));
1282         if (!vstream) {
1283                 DBG("Client requested index of unknown stream id %" PRIu64,
1284                                 be64toh(request_index.stream_id));
1285                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1286                 goto send_reply;
1287         }
1288
1289         /* Use back. ref. Protected by refcounts. */
1290         rstream = vstream->stream;
1291         ctf_trace = rstream->trace;
1292
1293         /* metadata_viewer_stream may be NULL. */
1294         metadata_viewer_stream =
1295                         ctf_trace_get_viewer_metadata_stream(ctf_trace);
1296
1297         pthread_mutex_lock(&rstream->lock);
1298
1299         /*
1300          * The viewer should not ask for index on metadata stream.
1301          */
1302         if (rstream->is_metadata) {
1303                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1304                 goto send_reply;
1305         }
1306
1307         /* Try to open an index if one is needed for that stream. */
1308         ret = try_open_index(vstream, rstream);
1309         if (ret < 0) {
1310                 if (ret == -ENOENT) {
1311                         /*
1312                          * The index is created only when the first data
1313                          * packet arrives, it might not be ready at the
1314                          * beginning of the session
1315                          */
1316                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1317                 } else {
1318                         /* Unhandled error. */
1319                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1320                 }
1321                 goto send_reply;
1322         }
1323
1324         ret = check_index_status(vstream, rstream, ctf_trace, &viewer_index);
1325         if (ret < 0) {
1326                 goto error_put;
1327         } else if (ret == 1) {
1328                 /*
1329                  * We have no index to send and check_index_status has populated
1330                  * viewer_index's status.
1331                  */
1332                 goto send_reply;
1333         }
1334         /* At this point, ret is 0 thus we will be able to read the index. */
1335         assert(!ret);
1336
1337         /*
1338          * vstream->stream_fd may be NULL if it has been closed by
1339          * tracefile rotation, or if we are at the beginning of the
1340          * stream. We open the data stream file here to protect against
1341          * overwrite caused by tracefile rotation (in association with
1342          * unlink performed before overwrite).
1343          */
1344         if (!vstream->stream_fd) {
1345                 char fullpath[PATH_MAX];
1346
1347                 if (vstream->stream->tracefile_count > 0) {
1348                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64,
1349                                         vstream->path_name,
1350                                         vstream->channel_name,
1351                                         vstream->current_tracefile_id);
1352                 } else {
1353                         ret = snprintf(fullpath, PATH_MAX, "%s/%s",
1354                                         vstream->path_name,
1355                                         vstream->channel_name);
1356                 }
1357                 if (ret < 0) {
1358                         goto error_put;
1359                 }
1360                 ret = open(fullpath, O_RDONLY);
1361                 if (ret < 0) {
1362                         PERROR("Relay opening trace file");
1363                         goto error_put;
1364                 }
1365                 vstream->stream_fd = stream_fd_create(ret);
1366                 if (!vstream->stream_fd) {
1367                         if (close(ret)) {
1368                                 PERROR("close");
1369                         }
1370                         goto error_put;
1371                 }
1372         }
1373
1374         ret = check_new_streams(conn);
1375         if (ret < 0) {
1376                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1377                 goto send_reply;
1378         } else if (ret == 1) {
1379                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1380         }
1381
1382         read_ret = lttng_read(vstream->index_fd->fd, &packet_index,
1383                         sizeof(packet_index));
1384         if (read_ret < sizeof(packet_index)) {
1385                 ERR("Relay reading index file %d returned %zd",
1386                         vstream->index_fd->fd, read_ret);
1387                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1388                 goto send_reply;
1389         } else {
1390                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_OK);
1391                 vstream->index_sent_seqcount++;
1392         }
1393
1394         /*
1395          * Indexes are stored in big endian, no need to switch before sending.
1396          */
1397         DBG("Sending viewer index for stream %" PRIu64 " offset %" PRIu64,
1398                 rstream->stream_handle,
1399                 be64toh(packet_index.offset));
1400         viewer_index.offset = packet_index.offset;
1401         viewer_index.packet_size = packet_index.packet_size;
1402         viewer_index.content_size = packet_index.content_size;
1403         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1404         viewer_index.timestamp_end = packet_index.timestamp_end;
1405         viewer_index.events_discarded = packet_index.events_discarded;
1406         viewer_index.stream_id = packet_index.stream_id;
1407
1408 send_reply:
1409         if (rstream) {
1410                 pthread_mutex_unlock(&rstream->lock);
1411         }
1412
1413         if (metadata_viewer_stream) {
1414                 pthread_mutex_lock(&metadata_viewer_stream->stream->lock);
1415                 DBG("get next index metadata check: recv %" PRIu64
1416                                 " sent %" PRIu64,
1417                         metadata_viewer_stream->stream->metadata_received,
1418                         metadata_viewer_stream->metadata_sent);
1419                 if (!metadata_viewer_stream->stream->metadata_received ||
1420                                 metadata_viewer_stream->stream->metadata_received >
1421                                         metadata_viewer_stream->metadata_sent) {
1422                         viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1423                 }
1424                 pthread_mutex_unlock(&metadata_viewer_stream->stream->lock);
1425         }
1426
1427         viewer_index.flags = htobe32(viewer_index.flags);
1428         health_code_update();
1429
1430         ret = send_response(conn->sock, &viewer_index, sizeof(viewer_index));
1431         if (ret < 0) {
1432                 goto end;
1433         }
1434         health_code_update();
1435
1436         if (vstream) {
1437                 DBG("Index %" PRIu64 " for stream %" PRIu64 " sent",
1438                                 vstream->index_sent_seqcount,
1439                                 vstream->stream->stream_handle);
1440         }
1441 end:
1442         if (metadata_viewer_stream) {
1443                 viewer_stream_put(metadata_viewer_stream);
1444         }
1445         if (vstream) {
1446                 viewer_stream_put(vstream);
1447         }
1448         return ret;
1449
1450 error_put:
1451         pthread_mutex_unlock(&rstream->lock);
1452         if (metadata_viewer_stream) {
1453                 viewer_stream_put(metadata_viewer_stream);
1454         }
1455         viewer_stream_put(vstream);
1456         return ret;
1457 }
1458
1459 /*
1460  * Send the next index for a stream
1461  *
1462  * Return 0 on success or else a negative value.
1463  */
1464 static
1465 int viewer_get_packet(struct relay_connection *conn)
1466 {
1467         int ret, send_data = 0;
1468         char *data = NULL;
1469         uint32_t len = 0;
1470         ssize_t read_len;
1471         struct lttng_viewer_get_packet get_packet_info;
1472         struct lttng_viewer_trace_packet reply;
1473         struct relay_viewer_stream *vstream = NULL;
1474
1475         DBG2("Relay get data packet");
1476
1477         health_code_update();
1478
1479         ret = recv_request(conn->sock, &get_packet_info,
1480                         sizeof(get_packet_info));
1481         if (ret < 0) {
1482                 goto end;
1483         }
1484         health_code_update();
1485
1486         /* From this point on, the error label can be reached. */
1487         memset(&reply, 0, sizeof(reply));
1488
1489         vstream = viewer_stream_get_by_id(be64toh(get_packet_info.stream_id));
1490         if (!vstream) {
1491                 DBG("Client requested packet of unknown stream id %" PRIu64,
1492                                 be64toh(get_packet_info.stream_id));
1493                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1494                 goto send_reply_nolock;
1495         }
1496
1497         pthread_mutex_lock(&vstream->stream->lock);
1498
1499         len = be32toh(get_packet_info.len);
1500         data = zmalloc(len);
1501         if (!data) {
1502                 PERROR("relay data zmalloc");
1503                 goto error;
1504         }
1505
1506         ret = lseek(vstream->stream_fd->fd, be64toh(get_packet_info.offset),
1507                         SEEK_SET);
1508         if (ret < 0) {
1509                 PERROR("lseek fd %d to offset %" PRIu64, vstream->stream_fd->fd,
1510                         be64toh(get_packet_info.offset));
1511                 goto error;
1512         }
1513         read_len = lttng_read(vstream->stream_fd->fd, data, len);
1514         if (read_len < len) {
1515                 PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1516                                 vstream->stream_fd->fd,
1517                                 be64toh(get_packet_info.offset));
1518                 goto error;
1519         }
1520         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_OK);
1521         reply.len = htobe32(len);
1522         send_data = 1;
1523         goto send_reply;
1524
1525 error:
1526         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1527
1528 send_reply:
1529         if (vstream) {
1530                 pthread_mutex_unlock(&vstream->stream->lock);
1531         }
1532 send_reply_nolock:
1533         reply.flags = htobe32(reply.flags);
1534
1535         health_code_update();
1536
1537         ret = send_response(conn->sock, &reply, sizeof(reply));
1538         if (ret < 0) {
1539                 goto end_free;
1540         }
1541         health_code_update();
1542
1543         if (send_data) {
1544                 health_code_update();
1545                 ret = send_response(conn->sock, data, len);
1546                 if (ret < 0) {
1547                         goto end_free;
1548                 }
1549                 health_code_update();
1550         }
1551
1552         DBG("Sent %u bytes for stream %" PRIu64, len,
1553                         be64toh(get_packet_info.stream_id));
1554
1555 end_free:
1556         free(data);
1557 end:
1558         if (vstream) {
1559                 viewer_stream_put(vstream);
1560         }
1561         return ret;
1562 }
1563
1564 /*
1565  * Send the session's metadata
1566  *
1567  * Return 0 on success else a negative value.
1568  */
1569 static
1570 int viewer_get_metadata(struct relay_connection *conn)
1571 {
1572         int ret = 0;
1573         ssize_t read_len;
1574         uint64_t len = 0;
1575         char *data = NULL;
1576         struct lttng_viewer_get_metadata request;
1577         struct lttng_viewer_metadata_packet reply;
1578         struct relay_viewer_stream *vstream = NULL;
1579
1580         assert(conn);
1581
1582         DBG("Relay get metadata");
1583
1584         health_code_update();
1585
1586         ret = recv_request(conn->sock, &request, sizeof(request));
1587         if (ret < 0) {
1588                 goto end;
1589         }
1590         health_code_update();
1591
1592         memset(&reply, 0, sizeof(reply));
1593
1594         vstream = viewer_stream_get_by_id(be64toh(request.stream_id));
1595         if (!vstream) {
1596                 /*
1597                  * The metadata stream can be closed by a CLOSE command
1598                  * just before we attach. It can also be closed by
1599                  * per-pid tracing during tracing. Therefore, it is
1600                  * possible that we cannot find this viewer stream.
1601                  * Reply back to the client with an error if we cannot
1602                  * find it.
1603                  */
1604                 DBG("Client requested metadata of unknown stream id %" PRIu64,
1605                                 be64toh(request.stream_id));
1606                 reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1607                 goto send_reply;
1608         }
1609         pthread_mutex_lock(&vstream->stream->lock);
1610         if (!vstream->stream->is_metadata) {
1611                 ERR("Invalid metadata stream");
1612                 goto error;
1613         }
1614
1615         assert(vstream->metadata_sent <= vstream->stream->metadata_received);
1616
1617         len = vstream->stream->metadata_received - vstream->metadata_sent;
1618         if (len == 0) {
1619                 reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
1620                 goto send_reply;
1621         }
1622
1623         /* first time, we open the metadata file */
1624         if (!vstream->stream_fd) {
1625                 char fullpath[PATH_MAX];
1626
1627                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", vstream->path_name,
1628                                 vstream->channel_name);
1629                 if (ret < 0) {
1630                         goto error;
1631                 }
1632                 ret = open(fullpath, O_RDONLY);
1633                 if (ret < 0) {
1634                         PERROR("Relay opening metadata file");
1635                         goto error;
1636                 }
1637                 vstream->stream_fd = stream_fd_create(ret);
1638                 if (!vstream->stream_fd) {
1639                         if (close(ret)) {
1640                                 PERROR("close");
1641                         }
1642                         goto error;
1643                 }
1644         }
1645
1646         reply.len = htobe64(len);
1647         data = zmalloc(len);
1648         if (!data) {
1649                 PERROR("viewer metadata zmalloc");
1650                 goto error;
1651         }
1652
1653         read_len = lttng_read(vstream->stream_fd->fd, data, len);
1654         if (read_len < len) {
1655                 PERROR("Relay reading metadata file");
1656                 goto error;
1657         }
1658         vstream->metadata_sent += read_len;
1659         if (vstream->metadata_sent == vstream->stream->metadata_received
1660                         && vstream->stream->closed) {
1661                 /* Release ownership for the viewer metadata stream. */
1662                 viewer_stream_put(vstream);
1663         }
1664
1665         reply.status = htobe32(LTTNG_VIEWER_METADATA_OK);
1666
1667         goto send_reply;
1668
1669 error:
1670         reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1671
1672 send_reply:
1673         health_code_update();
1674         if (vstream) {
1675                 pthread_mutex_unlock(&vstream->stream->lock);
1676         }
1677         ret = send_response(conn->sock, &reply, sizeof(reply));
1678         if (ret < 0) {
1679                 goto end_free;
1680         }
1681         health_code_update();
1682
1683         if (len > 0) {
1684                 ret = send_response(conn->sock, data, len);
1685                 if (ret < 0) {
1686                         goto end_free;
1687                 }
1688         }
1689
1690         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1691                         be64toh(request.stream_id));
1692
1693         DBG("Metadata sent");
1694
1695 end_free:
1696         free(data);
1697 end:
1698         if (vstream) {
1699                 viewer_stream_put(vstream);
1700         }
1701         return ret;
1702 }
1703
1704 /*
1705  * Create a viewer session.
1706  *
1707  * Return 0 on success or else a negative value.
1708  */
1709 static
1710 int viewer_create_session(struct relay_connection *conn)
1711 {
1712         int ret;
1713         struct lttng_viewer_create_session_response resp;
1714
1715         DBG("Viewer create session received");
1716
1717         memset(&resp, 0, sizeof(resp));
1718         resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_OK);
1719         conn->viewer_session = viewer_session_create();
1720         if (!conn->viewer_session) {
1721                 ERR("Allocation viewer session");
1722                 resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_ERR);
1723                 goto send_reply;
1724         }
1725
1726 send_reply:
1727         health_code_update();
1728         ret = send_response(conn->sock, &resp, sizeof(resp));
1729         if (ret < 0) {
1730                 goto end;
1731         }
1732         health_code_update();
1733         ret = 0;
1734
1735 end:
1736         return ret;
1737 }
1738
1739
1740 /*
1741  * live_relay_unknown_command: send -1 if received unknown command
1742  */
1743 static
1744 void live_relay_unknown_command(struct relay_connection *conn)
1745 {
1746         struct lttcomm_relayd_generic_reply reply;
1747
1748         memset(&reply, 0, sizeof(reply));
1749         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1750         (void) send_response(conn->sock, &reply, sizeof(reply));
1751 }
1752
1753 /*
1754  * Process the commands received on the control socket
1755  */
1756 static
1757 int process_control(struct lttng_viewer_cmd *recv_hdr,
1758                 struct relay_connection *conn)
1759 {
1760         int ret = 0;
1761         uint32_t msg_value;
1762
1763         msg_value = be32toh(recv_hdr->cmd);
1764
1765         /*
1766          * Make sure we've done the version check before any command other then a
1767          * new client connection.
1768          */
1769         if (msg_value != LTTNG_VIEWER_CONNECT && !conn->version_check_done) {
1770                 ERR("Viewer conn value %" PRIu32 " before version check", msg_value);
1771                 ret = -1;
1772                 goto end;
1773         }
1774
1775         switch (msg_value) {
1776         case LTTNG_VIEWER_CONNECT:
1777                 ret = viewer_connect(conn);
1778                 break;
1779         case LTTNG_VIEWER_LIST_SESSIONS:
1780                 ret = viewer_list_sessions(conn);
1781                 break;
1782         case LTTNG_VIEWER_ATTACH_SESSION:
1783                 ret = viewer_attach_session(conn);
1784                 break;
1785         case LTTNG_VIEWER_GET_NEXT_INDEX:
1786                 ret = viewer_get_next_index(conn);
1787                 break;
1788         case LTTNG_VIEWER_GET_PACKET:
1789                 ret = viewer_get_packet(conn);
1790                 break;
1791         case LTTNG_VIEWER_GET_METADATA:
1792                 ret = viewer_get_metadata(conn);
1793                 break;
1794         case LTTNG_VIEWER_GET_NEW_STREAMS:
1795                 ret = viewer_get_new_streams(conn);
1796                 break;
1797         case LTTNG_VIEWER_CREATE_SESSION:
1798                 ret = viewer_create_session(conn);
1799                 break;
1800         default:
1801                 ERR("Received unknown viewer command (%u)",
1802                                 be32toh(recv_hdr->cmd));
1803                 live_relay_unknown_command(conn);
1804                 ret = -1;
1805                 goto end;
1806         }
1807
1808 end:
1809         return ret;
1810 }
1811
1812 static
1813 void cleanup_connection_pollfd(struct lttng_poll_event *events, int pollfd)
1814 {
1815         int ret;
1816
1817         (void) lttng_poll_del(events, pollfd);
1818
1819         ret = close(pollfd);
1820         if (ret < 0) {
1821                 ERR("Closing pollfd %d", pollfd);
1822         }
1823 }
1824
1825 /*
1826  * This thread does the actual work
1827  */
1828 static
1829 void *thread_worker(void *data)
1830 {
1831         int ret, err = -1;
1832         uint32_t nb_fd;
1833         struct lttng_poll_event events;
1834         struct lttng_ht *viewer_connections_ht;
1835         struct lttng_ht_iter iter;
1836         struct lttng_viewer_cmd recv_hdr;
1837         struct relay_connection *destroy_conn;
1838
1839         DBG("[thread] Live viewer relay worker started");
1840
1841         rcu_register_thread();
1842
1843         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1844
1845         if (testpoint(relayd_thread_live_worker)) {
1846                 goto error_testpoint;
1847         }
1848
1849         /* table of connections indexed on socket */
1850         viewer_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1851         if (!viewer_connections_ht) {
1852                 goto viewer_connections_ht_error;
1853         }
1854
1855         ret = create_thread_poll_set(&events, 2);
1856         if (ret < 0) {
1857                 goto error_poll_create;
1858         }
1859
1860         ret = lttng_poll_add(&events, live_conn_pipe[0], LPOLLIN | LPOLLRDHUP);
1861         if (ret < 0) {
1862                 goto error;
1863         }
1864
1865 restart:
1866         while (1) {
1867                 int i;
1868
1869                 health_code_update();
1870
1871                 /* Infinite blocking call, waiting for transmission */
1872                 DBG3("Relayd live viewer worker thread polling...");
1873                 health_poll_entry();
1874                 ret = lttng_poll_wait(&events, -1);
1875                 health_poll_exit();
1876                 if (ret < 0) {
1877                         /*
1878                          * Restart interrupted system call.
1879                          */
1880                         if (errno == EINTR) {
1881                                 goto restart;
1882                         }
1883                         goto error;
1884                 }
1885
1886                 nb_fd = ret;
1887
1888                 /*
1889                  * Process control. The control connection is prioritised so we don't
1890                  * starve it with high throughput tracing data on the data
1891                  * connection.
1892                  */
1893                 for (i = 0; i < nb_fd; i++) {
1894                         /* Fetch once the poll data */
1895                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1896                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1897
1898                         health_code_update();
1899
1900                         if (!revents) {
1901                                 /* No activity for this FD (poll implementation). */
1902                                 continue;
1903                         }
1904
1905                         /* Thread quit pipe has been closed. Killing thread. */
1906                         ret = check_thread_quit_pipe(pollfd, revents);
1907                         if (ret) {
1908                                 err = 0;
1909                                 goto exit;
1910                         }
1911
1912                         /* Inspect the relay conn pipe for new connection. */
1913                         if (pollfd == live_conn_pipe[0]) {
1914                                 if (revents & LPOLLIN) {
1915                                         struct relay_connection *conn;
1916
1917                                         ret = lttng_read(live_conn_pipe[0],
1918                                                         &conn, sizeof(conn));
1919                                         if (ret < 0) {
1920                                                 goto error;
1921                                         }
1922                                         lttng_poll_add(&events, conn->sock->fd,
1923                                                         LPOLLIN | LPOLLRDHUP);
1924                                         connection_ht_add(viewer_connections_ht, conn);
1925                                         DBG("Connection socket %d added to poll", conn->sock->fd);
1926                                 } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1927                                         ERR("Relay live pipe error");
1928                                         goto error;
1929                                 } else {
1930                                         ERR("Unexpected poll events %u for sock %d", revents, pollfd);
1931                                         goto error;
1932                                 }
1933                         } else {
1934                                 /* Connection activity. */
1935                                 struct relay_connection *conn;
1936
1937                                 conn = connection_get_by_sock(viewer_connections_ht, pollfd);
1938                                 if (!conn) {
1939                                         continue;
1940                                 }
1941
1942                                 if (revents & LPOLLIN) {
1943                                         ret = conn->sock->ops->recvmsg(conn->sock, &recv_hdr,
1944                                                         sizeof(recv_hdr), 0);
1945                                         if (ret <= 0) {
1946                                                 /* Connection closed. */
1947                                                 cleanup_connection_pollfd(&events, pollfd);
1948                                                 /* Put "create" ownership reference. */
1949                                                 connection_put(conn);
1950                                                 DBG("Viewer control conn closed with %d", pollfd);
1951                                         } else {
1952                                                 ret = process_control(&recv_hdr, conn);
1953                                                 if (ret < 0) {
1954                                                         /* Clear the session on error. */
1955                                                         cleanup_connection_pollfd(&events, pollfd);
1956                                                         /* Put "create" ownership reference. */
1957                                                         connection_put(conn);
1958                                                         DBG("Viewer connection closed with %d", pollfd);
1959                                                 }
1960                                         }
1961                                 } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1962                                         cleanup_connection_pollfd(&events, pollfd);
1963                                         /* Put "create" ownership reference. */
1964                                         connection_put(conn);
1965                                 } else {
1966                                         ERR("Unexpected poll events %u for sock %d", revents, pollfd);
1967                                         connection_put(conn);
1968                                         goto error;
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 }