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
 311                          * lock.
 312                          */
 313                         if (!stream->published) {
 314                                 goto next;
 315                         }
 316                         vstream = viewer_stream_get_by_id(stream->stream_handle);
 317                         if (!vstream) {
 318                                 vstream = viewer_stream_create(stream, seek_t);
 319                                 if (!vstream) {
 320                                         ret = -1;
 321                                         ctf_trace_put(ctf_trace);
 322                                         stream_put(stream);
 323                                         goto error_unlock;
 324                                 }
 325
 326                                 if (nb_created) {
 327                                         /* Update number of created stream counter. */
 328                                         (*nb_created)++;
 329                                 }
 330                         } else {
 331                                 if (!vstream->sent_flag && nb_unsent) {
 332                                         /* Update number of unsent stream counter. */
 333                                         (*nb_unsent)++;
 334                                 }
 335                                 viewer_stream_put(vstream);
 336                         }
 337                         /* Update number of total stream counter. */
 338                         if (nb_total) {
 339                                 (*nb_total)++;
 340                         }
 341                 next:
 342                         stream_put(stream);
 343                 }
 344                 ctf_trace_put(ctf_trace);
 345         }
 346
 347         ret = 0;
 348
 349 error_unlock:
 350         rcu_read_unlock();
 351         pthread_mutex_unlock(&session->lock);
 352         return ret;
 353 }
 354
 355 int relayd_live_stop(void)
 356 {
 357         /* Stop dispatch thread */
 358         CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
 359         futex_nto1_wake(&viewer_conn_queue.futex);
 360         return 0;
 361 }
 362
 363 /*
 364  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 365  */
 366 static
 367 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 368 {
 369         int ret;
 370
 371         if (events == NULL || size == 0) {
 372                 ret = -1;
 373                 goto error;
 374         }
 375
 376         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 377         if (ret < 0) {
 378                 goto error;
 379         }
 380
 381         /* Add quit pipe */
 382         ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
 383         if (ret < 0) {
 384                 goto error;
 385         }
 386
 387         return 0;
 388
 389 error:
 390         return ret;
 391 }
 392
 393 /*
 394  * Check if the thread quit pipe was triggered.
 395  *
 396  * Return 1 if it was triggered else 0;
 397  */
 398 static
 399 int check_thread_quit_pipe(int fd, uint32_t events)
 400 {
 401         if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
 402                 return 1;
 403         }
 404
 405         return 0;
 406 }
 407
 408 /*
 409  * Create and init socket from uri.
 410  */
 411 static
 412 struct lttcomm_sock *init_socket(struct lttng_uri *uri)
 413 {
 414         int ret;
 415         struct lttcomm_sock *sock = NULL;
 416
 417         sock = lttcomm_alloc_sock_from_uri(uri);
 418         if (sock == NULL) {
 419                 ERR("Allocating socket");
 420                 goto error;
 421         }
 422
 423         ret = lttcomm_create_sock(sock);
 424         if (ret < 0) {
 425                 goto error;
 426         }
 427         DBG("Listening on sock %d for live", sock->fd);
 428
 429         ret = sock->ops->bind(sock);
 430         if (ret < 0) {
 431                 goto error;
 432         }
 433
 434         ret = sock->ops->listen(sock, -1);
 435         if (ret < 0) {
 436                 goto error;
 437
 438         }
 439
 440         return sock;
 441
 442 error:
 443         if (sock) {
 444                 lttcomm_destroy_sock(sock);
 445         }
 446         return NULL;
 447 }
 448
 449 /*
 450  * This thread manages the listening for new connections on the network
 451  */
 452 static
 453 void *thread_listener(void *data)
 454 {
 455         int i, ret, pollfd, err = -1;
 456         uint32_t revents, nb_fd;
 457         struct lttng_poll_event events;
 458         struct lttcomm_sock *live_control_sock;
 459
 460         DBG("[thread] Relay live listener started");
 461
 462         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_LISTENER);
 463
 464         health_code_update();
 465
 466         live_control_sock = init_socket(live_uri);
 467         if (!live_control_sock) {
 468                 goto error_sock_control;
 469         }
 470
 471         /* Pass 2 as size here for the thread quit pipe and control sockets. */
 472         ret = create_thread_poll_set(&events, 2);
 473         if (ret < 0) {
 474                 goto error_create_poll;
 475         }
 476
 477         /* Add the control socket */
 478         ret = lttng_poll_add(&events, live_control_sock->fd, LPOLLIN | LPOLLRDHUP);
 479         if (ret < 0) {
 480                 goto error_poll_add;
 481         }
 482
 483         lttng_relay_notify_ready();
 484
 485         if (testpoint(relayd_thread_live_listener)) {
 486                 goto error_testpoint;
 487         }
 488
 489         while (1) {
 490                 health_code_update();
 491
 492                 DBG("Listener accepting live viewers connections");
 493
 494 restart:
 495                 health_poll_entry();
 496                 ret = lttng_poll_wait(&events, -1);
 497                 health_poll_exit();
 498                 if (ret < 0) {
 499                         /*
 500                          * Restart interrupted system call.
 501                          */
 502                         if (errno == EINTR) {
 503                                 goto restart;
 504                         }
 505                         goto error;
 506                 }
 507                 nb_fd = ret;
 508
 509                 DBG("Relay new viewer connection received");
 510                 for (i = 0; i < nb_fd; i++) {
 511                         health_code_update();
 512
 513                         /* Fetch once the poll data */
 514                         revents = LTTNG_POLL_GETEV(&events, i);
 515                         pollfd = LTTNG_POLL_GETFD(&events, i);
 516
 517                         if (!revents) {
 518                                 /* No activity for this FD (poll implementation). */
 519                                 continue;
 520                         }
 521
 522                         /* Thread quit pipe has been closed. Killing thread. */
 523                         ret = check_thread_quit_pipe(pollfd, revents);
 524                         if (ret) {
 525                                 err = 0;
 526                                 goto exit;
 527                         }
 528
 529                         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 530                                 ERR("socket poll error");
 531                                 goto error;
 532                         } else if (revents & LPOLLIN) {
 533                                 /*
 534                                  * A new connection is requested, therefore a
 535                                  * viewer connection is allocated in this
 536                                  * thread, enqueued to a global queue and
 537                                  * dequeued (and freed) in the worker thread.
 538                                  */
 539                                 int val = 1;
 540                                 struct relay_connection *new_conn;
 541                                 struct lttcomm_sock *newsock;
 542
 543                                 newsock = live_control_sock->ops->accept(live_control_sock);
 544                                 if (!newsock) {
 545                                         PERROR("accepting control sock");
 546                                         goto error;
 547                                 }
 548                                 DBG("Relay viewer connection accepted socket %d", newsock->fd);
 549
 550                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR, &val,
 551                                                 sizeof(val));
 552                                 if (ret < 0) {
 553                                         PERROR("setsockopt inet");
 554                                         lttcomm_destroy_sock(newsock);
 555                                         goto error;
 556                                 }
 557                                 new_conn = connection_create(newsock, RELAY_CONNECTION_UNKNOWN);
 558                                 if (!new_conn) {
 559                                         lttcomm_destroy_sock(newsock);
 560                                         goto error;
 561                                 }
 562                                 /* Ownership assumed by the connection. */
 563                                 newsock = NULL;
 564
 565                                 /* Enqueue request for the dispatcher thread. */
 566                                 cds_wfcq_enqueue(&viewer_conn_queue.head, &viewer_conn_queue.tail,
 567                                                  &new_conn->qnode);
 568
 569                                 /*
 570                                  * Wake the dispatch queue futex.
 571                                  * Implicit memory barrier with the
 572                                  * exchange in cds_wfcq_enqueue.
 573                                  */
 574                                 futex_nto1_wake(&viewer_conn_queue.futex);
 575                         }
 576                 }
 577         }
 578
 579 exit:
 580 error:
 581 error_poll_add:
 582 error_testpoint:
 583         lttng_poll_clean(&events);
 584 error_create_poll:
 585         if (live_control_sock->fd >= 0) {
 586                 ret = live_control_sock->ops->close(live_control_sock);
 587                 if (ret) {
 588                         PERROR("close");
 589                 }
 590         }
 591         lttcomm_destroy_sock(live_control_sock);
 592 error_sock_control:
 593         if (err) {
 594                 health_error();
 595                 DBG("Live viewer listener thread exited with error");
 596         }
 597         health_unregister(health_relayd);
 598         DBG("Live viewer listener thread cleanup complete");
 599         if (lttng_relay_stop_threads()) {
 600                 ERR("Error stopping threads");
 601         }
 602         return NULL;
 603 }
 604
 605 /*
 606  * This thread manages the dispatching of the requests to worker threads
 607  */
 608 static
 609 void *thread_dispatcher(void *data)
 610 {
 611         int err = -1;
 612         ssize_t ret;
 613         struct cds_wfcq_node *node;
 614         struct relay_connection *conn = NULL;
 615
 616         DBG("[thread] Live viewer relay dispatcher started");
 617
 618         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 619
 620         if (testpoint(relayd_thread_live_dispatcher)) {
 621                 goto error_testpoint;
 622         }
 623
 624         health_code_update();
 625
 626         while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 627                 health_code_update();
 628
 629                 /* Atomically prepare the queue futex */
 630                 futex_nto1_prepare(&viewer_conn_queue.futex);
 631
 632                 do {
 633                         health_code_update();
 634
 635                         /* Dequeue commands */
 636                         node = cds_wfcq_dequeue_blocking(&viewer_conn_queue.head,
 637                                                          &viewer_conn_queue.tail);
 638                         if (node == NULL) {
 639                                 DBG("Woken up but nothing in the live-viewer "
 640                                                 "relay command queue");
 641                                 /* Continue thread execution */
 642                                 break;
 643                         }
 644                         conn = caa_container_of(node, struct relay_connection, qnode);
 645                         DBG("Dispatching viewer request waiting on sock %d",
 646                                         conn->sock->fd);
 647
 648                         /*
 649                          * Inform worker thread of the new request. This
 650                          * call is blocking so we can be assured that
 651                          * the data will be read at some point in time
 652                          * or wait to the end of the world :)
 653                          */
 654                         ret = lttng_write(live_conn_pipe[1], &conn, sizeof(conn));
 655                         if (ret < 0) {
 656                                 PERROR("write conn pipe");
 657                                 connection_put(conn);
 658                                 goto error;
 659                         }
 660                 } while (node != NULL);
 661
 662                 /* Futex wait on queue. Blocking call on futex() */
 663                 health_poll_entry();
 664                 futex_nto1_wait(&viewer_conn_queue.futex);
 665                 health_poll_exit();
 666         }
 667
 668         /* Normal exit, no error */
 669         err = 0;
 670
 671 error:
 672 error_testpoint:
 673         if (err) {
 674                 health_error();
 675                 ERR("Health error occurred in %s", __func__);
 676         }
 677         health_unregister(health_relayd);
 678         DBG("Live viewer dispatch thread dying");
 679         if (lttng_relay_stop_threads()) {
 680                 ERR("Error stopping threads");
 681         }
 682         return NULL;
 683 }
 684
 685 /*
 686  * Establish connection with the viewer and check the versions.
 687  *
 688  * Return 0 on success or else negative value.
 689  */
 690 static
 691 int viewer_connect(struct relay_connection *conn)
 692 {
 693         int ret;
 694         struct lttng_viewer_connect reply, msg;
 695
 696         conn->version_check_done = 1;
 697
 698         health_code_update();
 699
 700         DBG("Viewer is establishing a connection to the relayd.");
 701
 702         ret = recv_request(conn->sock, &msg, sizeof(msg));
 703         if (ret < 0) {
 704                 goto end;
 705         }
 706
 707         health_code_update();
 708
 709         memset(&reply, 0, sizeof(reply));
 710         reply.major = RELAYD_VERSION_COMM_MAJOR;
 711         reply.minor = RELAYD_VERSION_COMM_MINOR;
 712
 713         /* Major versions must be the same */
 714         if (reply.major != be32toh(msg.major)) {
 715                 DBG("Incompatible major versions ([relayd] %u vs [client] %u)",
 716                                 reply.major, be32toh(msg.major));
 717                 ret = -1;
 718                 goto end;
 719         }
 720
 721         conn->major = reply.major;
 722         /* We adapt to the lowest compatible version */
 723         if (reply.minor <= be32toh(msg.minor)) {
 724                 conn->minor = reply.minor;
 725         } else {
 726                 conn->minor = be32toh(msg.minor);
 727         }
 728
 729         if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_COMMAND) {
 730                 conn->type = RELAY_VIEWER_COMMAND;
 731         } else if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_NOTIFICATION) {
 732                 conn->type = RELAY_VIEWER_NOTIFICATION;
 733         } else {
 734                 ERR("Unknown connection type : %u", be32toh(msg.type));
 735                 ret = -1;
 736                 goto end;
 737         }
 738
 739         reply.major = htobe32(reply.major);
 740         reply.minor = htobe32(reply.minor);
 741         if (conn->type == RELAY_VIEWER_COMMAND) {
 742                 /*
 743                  * Increment outside of htobe64 macro, because the argument can
 744                  * be used more than once within the macro, and thus the
 745                  * operation may be undefined.
 746                  */
 747                 pthread_mutex_lock(&last_relay_viewer_session_id_lock);
 748                 last_relay_viewer_session_id++;
 749                 pthread_mutex_unlock(&last_relay_viewer_session_id_lock);
 750                 reply.viewer_session_id = htobe64(last_relay_viewer_session_id);
 751         }
 752
 753         health_code_update();
 754
 755         ret = send_response(conn->sock, &reply, sizeof(reply));
 756         if (ret < 0) {
 757                 goto end;
 758         }
 759
 760         health_code_update();
 761
 762         DBG("Version check done using protocol %u.%u", conn->major, conn->minor);
 763         ret = 0;
 764
 765 end:
 766         return ret;
 767 }
 768
 769 /*
 770  * Send the viewer the list of current sessions.
 771  * We need to create a copy of the hash table content because otherwise
 772  * we cannot assume the number of entries stays the same between getting
 773  * the number of HT elements and iteration over the HT.
 774  *
 775  * Return 0 on success or else a negative value.
 776  */
 777 static
 778 int viewer_list_sessions(struct relay_connection *conn)
 779 {
 780         int ret;
 781         struct lttng_viewer_list_sessions session_list;
 782         struct lttng_ht_iter iter;
 783         struct relay_session *session;
 784         struct lttng_viewer_session *send_session_buf = NULL;
 785         uint32_t buf_count = SESSION_BUF_DEFAULT_COUNT;
 786         uint32_t count = 0;
 787
 788         DBG("List sessions received");
 789
 790         send_session_buf = zmalloc(SESSION_BUF_DEFAULT_COUNT * sizeof(*send_session_buf));
 791         if (!send_session_buf) {
 792                 return -1;
 793         }
 794
 795         rcu_read_lock();
 796         cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
 797                         session_n.node) {
 798                 struct lttng_viewer_session *send_session;
 799
 800                 health_code_update();
 801
 802                 if (count >= buf_count) {
 803                         struct lttng_viewer_session *newbuf;
 804                         uint32_t new_buf_count = buf_count << 1;
 805
 806                         newbuf = realloc(send_session_buf,
 807                                 new_buf_count * sizeof(*send_session_buf));
 808                         if (!newbuf) {
 809                                 ret = -1;
 810                                 rcu_read_unlock();
 811                                 goto end_free;
 812                         }
 813                         send_session_buf = newbuf;
 814                         buf_count = new_buf_count;
 815                 }
 816                 send_session = &send_session_buf[count];
 817                 strncpy(send_session->session_name, session->session_name,
 818                                 sizeof(send_session->session_name));
 819                 strncpy(send_session->hostname, session->hostname,
 820                                 sizeof(send_session->hostname));
 821                 send_session->id = htobe64(session->id);
 822                 send_session->live_timer = htobe32(session->live_timer);
 823                 if (session->viewer_attached) {
 824                         send_session->clients = htobe32(1);
 825                 } else {
 826                         send_session->clients = htobe32(0);
 827                 }
 828                 send_session->streams = htobe32(session->stream_count);
 829                 count++;
 830         }
 831         rcu_read_unlock();
 832
 833         session_list.sessions_count = htobe32(count);
 834
 835         health_code_update();
 836
 837         ret = send_response(conn->sock, &session_list, sizeof(session_list));
 838         if (ret < 0) {
 839                 goto end_free;
 840         }
 841
 842         health_code_update();
 843
 844         ret = send_response(conn->sock, send_session_buf,
 845                         count * sizeof(*send_session_buf));
 846         if (ret < 0) {
 847                 goto end_free;
 848         }
 849         health_code_update();
 850
 851         ret = 0;
 852 end_free:
 853         free(send_session_buf);
 854         return ret;
 855 }
 856
 857 /*
 858  * Send the viewer the list of current streams.
 859  */
 860 static
 861 int viewer_get_new_streams(struct relay_connection *conn)
 862 {
 863         int ret, send_streams = 0;
 864         uint32_t nb_created = 0, nb_unsent = 0, nb_streams = 0, nb_total = 0;
 865         struct lttng_viewer_new_streams_request request;
 866         struct lttng_viewer_new_streams_response response;
 867         struct relay_session *session;
 868         uint64_t session_id;
 869         bool closed = false;
 870
 871         assert(conn);
 872
 873         DBG("Get new streams received");
 874
 875         health_code_update();
 876
 877         /* Receive the request from the connected client. */
 878         ret = recv_request(conn->sock, &request, sizeof(request));
 879         if (ret < 0) {
 880                 goto error;
 881         }
 882         session_id = be64toh(request.session_id);
 883
 884         health_code_update();
 885
 886         memset(&response, 0, sizeof(response));
 887
 888         session = session_get_by_id(session_id);
 889         if (!session) {
 890                 DBG("Relay session %" PRIu64 " not found", session_id);
 891                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 892                 goto send_reply;
 893         }
 894
 895         if (!viewer_session_is_attached(conn->viewer_session, session)) {
 896                 send_streams = 0;
 897                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 898                 goto send_reply;
 899         }
 900
 901         send_streams = 1;
 902         response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 903
 904         ret = make_viewer_streams(session, LTTNG_VIEWER_SEEK_LAST, &nb_total, &nb_unsent,
 905                         &nb_created, &closed);
 906         if (ret < 0) {
 907                 goto end_put_session;
 908         }
 909         /* Only send back the newly created streams with the unsent ones. */
 910         nb_streams = nb_created + nb_unsent;
 911         response.streams_count = htobe32(nb_streams);
 912
 913         /*
 914          * If the session is closed, HUP when there are no more streams.
 915          */
 916         if (closed && nb_total == 0) {
 917                 send_streams = 0;
 918                 response.streams_count = 0;
 919                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
 920                 goto send_reply;
 921         }
 922
 923 send_reply:
 924         health_code_update();
 925         ret = send_response(conn->sock, &response, sizeof(response));
 926         if (ret < 0) {
 927                 goto end_put_session;
 928         }
 929         health_code_update();
 930
 931         /*
 932          * Unknown or empty session, just return gracefully, the viewer
 933          * knows what is happening.
 934          */
 935         if (!send_streams || !nb_streams) {
 936                 ret = 0;
 937                 goto end_put_session;
 938         }
 939
 940         /*
 941          * Send stream and *DON'T* ignore the sent flag so every viewer
 942          * streams that were not sent from that point will be sent to
 943          * the viewer.
 944          */
 945         ret = send_viewer_streams(conn->sock, session, 0);
 946         if (ret < 0) {
 947                 goto end_put_session;
 948         }
 949
 950 end_put_session:
 951         if (session) {
 952                 session_put(session);
 953         }
 954 error:
 955         return ret;
 956 }
 957
 958 /*
 959  * Send the viewer the list of current sessions.
 960  */
 961 static
 962 int viewer_attach_session(struct relay_connection *conn)
 963 {
 964         int send_streams = 0;
 965         ssize_t ret;
 966         uint32_t nb_streams = 0;
 967         enum lttng_viewer_seek seek_type;
 968         struct lttng_viewer_attach_session_request request;
 969         struct lttng_viewer_attach_session_response response;
 970         struct relay_session *session = NULL;
 971         bool closed = false;
 972
 973         assert(conn);
 974
 975         health_code_update();
 976
 977         /* Receive the request from the connected client. */
 978         ret = recv_request(conn->sock, &request, sizeof(request));
 979         if (ret < 0) {
 980                 goto error;
 981         }
 982
 983         health_code_update();
 984
 985         memset(&response, 0, sizeof(response));
 986
 987         if (!conn->viewer_session) {
 988                 DBG("Client trying to attach before creating a live viewer session");
 989                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NO_SESSION);
 990                 goto send_reply;
 991         }
 992
 993         session = session_get_by_id(be64toh(request.session_id));
 994         if (!session) {
 995                 DBG("Relay session %" PRIu64 " not found",
 996                                 be64toh(request.session_id));
 997                 response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
 998                 goto send_reply;
 999         }
1000         DBG("Attach session ID %" PRIu64 " received",
1001                 be64toh(request.session_id));
1002
1003         if (session->live_timer == 0) {
1004                 DBG("Not live session");
1005                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NOT_LIVE);
1006                 goto send_reply;
1007         }
1008
1009         send_streams = 1;
1010         ret = viewer_session_attach(conn->viewer_session, session);
1011         if (ret) {
1012                 DBG("Already a viewer attached");
1013                 response.status = htobe32(LTTNG_VIEWER_ATTACH_ALREADY);
1014                 goto send_reply;
1015         }
1016
1017         switch (be32toh(request.seek)) {
1018         case LTTNG_VIEWER_SEEK_BEGINNING:
1019         case LTTNG_VIEWER_SEEK_LAST:
1020                 response.status = htobe32(LTTNG_VIEWER_ATTACH_OK);
1021                 seek_type = be32toh(request.seek);
1022                 break;
1023         default:
1024                 ERR("Wrong seek parameter");
1025                 response.status = htobe32(LTTNG_VIEWER_ATTACH_SEEK_ERR);
1026                 send_streams = 0;
1027                 goto send_reply;
1028         }
1029
1030         ret = make_viewer_streams(session, seek_type, &nb_streams, NULL,
1031                         NULL, &closed);
1032         if (ret < 0) {
1033                 goto end_put_session;
1034         }
1035         response.streams_count = htobe32(nb_streams);
1036
1037         /*
1038          * If the session is closed when the viewer is attaching, it
1039          * means some of the streams may have been concurrently removed,
1040          * so we don't allow the viewer to attach, even if there are
1041          * streams available.
1042          */
1043         if (closed) {
1044                 send_streams = 0;
1045                 response.streams_count = 0;
1046                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
1047                 goto send_reply;
1048         }
1049
1050 send_reply:
1051         health_code_update();
1052         ret = send_response(conn->sock, &response, sizeof(response));
1053         if (ret < 0) {
1054                 goto end_put_session;
1055         }
1056         health_code_update();
1057
1058         /*
1059          * Unknown or empty session, just return gracefully, the viewer
1060          * knows what is happening.
1061          */
1062         if (!send_streams || !nb_streams) {
1063                 ret = 0;
1064                 goto end_put_session;
1065         }
1066
1067         /* Send stream and ignore the sent flag. */
1068         ret = send_viewer_streams(conn->sock, session, 1);
1069         if (ret < 0) {
1070                 goto end_put_session;
1071         }
1072
1073 end_put_session:
1074         if (session) {
1075                 session_put(session);
1076         }
1077 error:
1078         return ret;
1079 }
1080
1081 /*
1082  * Open the index file if needed for the given vstream.
1083  *
1084  * If an index file is successfully opened, the vstream index_fd set with
1085  * it.
1086  *
1087  * Return 0 on success, a negative value on error (-ENOENT if not ready yet).
1088  *
1089  * Called with rstream lock held.
1090  */
1091 static int try_open_index(struct relay_viewer_stream *vstream,
1092                 struct relay_stream *rstream)
1093 {
1094         int ret = 0;
1095
1096         if (vstream->index_fd) {
1097                 goto end;
1098         }
1099
1100         /*
1101          * First time, we open the index file and at least one index is ready.
1102          */
1103         if (rstream->total_index_received == 0) {
1104                 ret = -ENOENT;
1105                 goto end;
1106         }
1107         ret = index_open(vstream->path_name, vstream->channel_name,
1108                         vstream->stream->tracefile_count,
1109                         vstream->current_tracefile_id);
1110         if (ret >= 0) {
1111                 vstream->index_fd = stream_fd_create(ret);
1112                 if (!vstream->index_fd) {
1113                         if (close(ret)) {
1114                                 PERROR("close");
1115                         }
1116                         ret = -1;
1117                 } else {
1118                         ret = 0;
1119                 }
1120                 goto end;
1121         }
1122
1123 end:
1124         return ret;
1125 }
1126
1127 /*
1128  * Check the status of the index for the given stream. This function
1129  * updates the index structure if needed and can put (close) the vstream
1130  * in the HUP situation.
1131  *
1132  * Return 0 means that we can proceed with the index. A value of 1 means
1133  * that the index has been updated and is ready to be sent to the
1134  * client. A negative value indicates an error that can't be handled.
1135  *
1136  * Called with rstream lock held.
1137  */
1138 static int check_index_status(struct relay_viewer_stream *vstream,
1139                 struct relay_stream *rstream, struct ctf_trace *trace,
1140                 struct lttng_viewer_index *index)
1141 {
1142         int ret;
1143
1144         if (trace->session->connection_closed
1145                         && rstream->total_index_received
1146                                 == vstream->last_sent_index) {
1147                 /* Last index sent and session connection is closed. */
1148                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1149                 goto hup;
1150         } else if (rstream->beacon_ts_end != -1ULL &&
1151                         rstream->total_index_received
1152                                 == vstream->last_sent_index) {
1153                 /*
1154                  * We've received a synchronization beacon and the last index
1155                  * available has been sent, the index for now is inactive.
1156                  *
1157                  * In this case, we have received a beacon which allows us to
1158                  * inform the client of a time interval during which we can
1159                  * guarantee that there are no events to read (and never will
1160                  * be).
1161                  */
1162                 index->status = htobe32(LTTNG_VIEWER_INDEX_INACTIVE);
1163                 index->timestamp_end = htobe64(rstream->beacon_ts_end);
1164                 index->stream_id = htobe64(rstream->ctf_stream_id);
1165                 goto index_ready;
1166         } else if (rstream->total_index_received <= vstream->last_sent_index) {
1167                 /*
1168                  * This actually checks the case where recv == last_sent.
1169                  * In this case, we have not received a beacon. Therefore, we
1170                  * can only ask the client to retry later.
1171                  */
1172                 index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1173                 goto index_ready;
1174         } else if (!viewer_stream_is_tracefile_seq_readable(vstream,
1175                         vstream->current_tracefile_seq)) {
1176                 /*
1177                  * The producer has overwritten our current file. We
1178                  * need to rotate.
1179                  */
1180                 DBG("Viewer stream %" PRIu64 " rotation due to overwrite",
1181                                 vstream->stream->stream_handle);
1182                 ret = viewer_stream_rotate(vstream);
1183                 if (ret < 0) {
1184                         goto end;
1185                 } else if (ret == 1) {
1186                         /* EOF across entire stream. */
1187                         index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1188                         goto hup;
1189                 }
1190                 assert(viewer_stream_is_tracefile_seq_readable(vstream,
1191                         vstream->current_tracefile_seq));
1192                 /* ret == 0 means successful so we continue. */
1193                 ret = 0;
1194         } else {
1195                 ssize_t read_ret;
1196                 char tmp[1];
1197
1198                 /*
1199                  * Use EOF on current index file to find out when we
1200                  * need to rotate.
1201                  */
1202                 read_ret = lttng_read(vstream->index_fd->fd, tmp, 1);
1203                 if (read_ret == 1) {
1204                         off_t seek_ret;
1205
1206                         /* There is still data to read. Rewind position. */
1207                         seek_ret = lseek(vstream->index_fd->fd, -1, SEEK_CUR);
1208                         if (seek_ret < 0) {
1209                                 ret = -1;
1210                                 goto end;
1211                         }
1212                         ret = 0;
1213                 } else if (read_ret == 0) {
1214                         /* EOF. We need to rotate. */
1215                         DBG("Viewer stream %" PRIu64 " rotation due to EOF",
1216                                         vstream->stream->stream_handle);
1217                         ret = viewer_stream_rotate(vstream);
1218                         if (ret < 0) {
1219                                 goto end;
1220                         } else if (ret == 1) {
1221                                 /* EOF across entire stream. */
1222                                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1223                                 goto hup;
1224                         }
1225                         assert(viewer_stream_is_tracefile_seq_readable(vstream,
1226                                 vstream->current_tracefile_seq));
1227                         /* ret == 0 means successful so we continue. */
1228                         ret = 0;
1229                 } else {
1230                         /* Error reading index. */
1231                         ret = -1;
1232                 }
1233         }
1234 end:
1235         return ret;
1236
1237 hup:
1238         viewer_stream_put(vstream);
1239 index_ready:
1240         return 1;
1241 }
1242
1243 /*
1244  * Send the next index for a stream.
1245  *
1246  * Return 0 on success or else a negative value.
1247  */
1248 static
1249 int viewer_get_next_index(struct relay_connection *conn)
1250 {
1251         int ret;
1252         ssize_t read_ret;
1253         struct lttng_viewer_get_next_index request_index;
1254         struct lttng_viewer_index viewer_index;
1255         struct ctf_packet_index packet_index;
1256         struct relay_viewer_stream *vstream = NULL;
1257         struct relay_stream *rstream = NULL;
1258         struct ctf_trace *ctf_trace = NULL;
1259         struct relay_viewer_stream *metadata_viewer_stream = NULL;
1260
1261         assert(conn);
1262
1263         DBG("Viewer get next index");
1264
1265         memset(&viewer_index, 0, sizeof(viewer_index));
1266         health_code_update();
1267
1268         ret = recv_request(conn->sock, &request_index, sizeof(request_index));
1269         if (ret < 0) {
1270                 goto end;
1271         }
1272         health_code_update();
1273
1274         vstream = viewer_stream_get_by_id(be64toh(request_index.stream_id));
1275         if (!vstream) {
1276                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1277                 goto send_reply;
1278         }
1279
1280         /* Use back. ref. Protected by refcounts. */
1281         rstream = vstream->stream;
1282         ctf_trace = rstream->trace;
1283
1284         /* metadata_viewer_stream may be NULL. */
1285         metadata_viewer_stream =
1286                         ctf_trace_get_viewer_metadata_stream(ctf_trace);
1287
1288         pthread_mutex_lock(&rstream->lock);
1289
1290         /*
1291          * The viewer should not ask for index on metadata stream.
1292          */
1293         if (rstream->is_metadata) {
1294                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1295                 goto send_reply;
1296         }
1297
1298         /* Try to open an index if one is needed for that stream. */
1299         ret = try_open_index(vstream, rstream);
1300         if (ret < 0) {
1301                 if (ret == -ENOENT) {
1302                         /*
1303                          * The index is created only when the first data
1304                          * packet arrives, it might not be ready at the
1305                          * beginning of the session
1306                          */
1307                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1308                 } else {
1309                         /* Unhandled error. */
1310                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1311                 }
1312                 goto send_reply;
1313         }
1314
1315         ret = check_index_status(vstream, rstream, ctf_trace, &viewer_index);
1316         if (ret < 0) {
1317                 goto error_put;
1318         } else if (ret == 1) {
1319                 /*
1320                  * We have no index to send and check_index_status has populated
1321                  * viewer_index's status.
1322                  */
1323                 goto send_reply;
1324         }
1325         /* At this point, ret is 0 thus we will be able to read the index. */
1326         assert(!ret);
1327
1328         /*
1329          * vstream->stream_fd may be NULL if it has been closed by
1330          * tracefile rotation, or if we are at the beginning of the
1331          * stream. We open the data stream file here to protect against
1332          * overwrite caused by tracefile rotation (in association with
1333          * unlink performed before overwrite).
1334          */
1335         if (!vstream->stream_fd) {
1336                 char fullpath[PATH_MAX];
1337
1338                 if (vstream->stream->tracefile_count > 0) {
1339                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64,
1340                                         vstream->path_name,
1341                                         vstream->channel_name,
1342                                         vstream->current_tracefile_id);
1343                 } else {
1344                         ret = snprintf(fullpath, PATH_MAX, "%s/%s",
1345                                         vstream->path_name,
1346                                         vstream->channel_name);
1347                 }
1348                 if (ret < 0) {
1349                         goto error_put;
1350                 }
1351                 ret = open(fullpath, O_RDONLY);
1352                 if (ret < 0) {
1353                         PERROR("Relay opening trace file");
1354                         goto error_put;
1355                 }
1356                 vstream->stream_fd = stream_fd_create(ret);
1357                 if (!vstream->stream_fd) {
1358                         if (close(ret)) {
1359                                 PERROR("close");
1360                         }
1361                         goto error_put;
1362                 }
1363         }
1364
1365         ret = check_new_streams(conn);
1366         if (ret < 0) {
1367                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1368                 goto send_reply;
1369         } else if (ret == 1) {
1370                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1371         }
1372
1373         read_ret = lttng_read(vstream->index_fd->fd, &packet_index,
1374                         sizeof(packet_index));
1375         if (read_ret < sizeof(packet_index)) {
1376                 ERR("Relay reading index file %d returned %zd",
1377                         vstream->index_fd->fd, read_ret);
1378                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1379                 goto send_reply;
1380         } else {
1381                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_OK);
1382                 vstream->last_sent_index++;
1383         }
1384
1385         /*
1386          * Indexes are stored in big endian, no need to switch before sending.
1387          */
1388         DBG("Sending viewer index for stream %" PRIu64 " offset %" PRIu64,
1389                 rstream->stream_handle,
1390                 be64toh(packet_index.offset));
1391         viewer_index.offset = packet_index.offset;
1392         viewer_index.packet_size = packet_index.packet_size;
1393         viewer_index.content_size = packet_index.content_size;
1394         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1395         viewer_index.timestamp_end = packet_index.timestamp_end;
1396         viewer_index.events_discarded = packet_index.events_discarded;
1397         viewer_index.stream_id = packet_index.stream_id;
1398
1399 send_reply:
1400         if (rstream) {
1401                 pthread_mutex_unlock(&rstream->lock);
1402         }
1403
1404         if (metadata_viewer_stream) {
1405                 pthread_mutex_lock(&metadata_viewer_stream->stream->lock);
1406                 DBG("get next index metadata check: recv %" PRIu64
1407                                 " sent %" PRIu64,
1408                         metadata_viewer_stream->stream->metadata_received,
1409                         metadata_viewer_stream->metadata_sent);
1410                 if (!metadata_viewer_stream->stream->metadata_received ||
1411                                 metadata_viewer_stream->stream->metadata_received >
1412                                         metadata_viewer_stream->metadata_sent) {
1413                         viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1414                 }
1415                 pthread_mutex_unlock(&metadata_viewer_stream->stream->lock);
1416         }
1417
1418         viewer_index.flags = htobe32(viewer_index.flags);
1419         health_code_update();
1420
1421         ret = send_response(conn->sock, &viewer_index, sizeof(viewer_index));
1422         if (ret < 0) {
1423                 goto end;
1424         }
1425         health_code_update();
1426
1427         DBG("Index %" PRIu64 " for stream %" PRIu64 " sent",
1428                         vstream->last_sent_index,
1429                         vstream->stream->stream_handle);
1430 end:
1431         if (metadata_viewer_stream) {
1432                 viewer_stream_put(metadata_viewer_stream);
1433         }
1434         if (vstream) {
1435                 viewer_stream_put(vstream);
1436         }
1437         return ret;
1438
1439 error_put:
1440         pthread_mutex_unlock(&rstream->lock);
1441         if (metadata_viewer_stream) {
1442                 viewer_stream_put(metadata_viewer_stream);
1443         }
1444         viewer_stream_put(vstream);
1445         return ret;
1446 }
1447
1448 /*
1449  * Send the next index for a stream
1450  *
1451  * Return 0 on success or else a negative value.
1452  */
1453 static
1454 int viewer_get_packet(struct relay_connection *conn)
1455 {
1456         int ret, send_data = 0;
1457         char *data = NULL;
1458         uint32_t len = 0;
1459         ssize_t read_len;
1460         struct lttng_viewer_get_packet get_packet_info;
1461         struct lttng_viewer_trace_packet reply;
1462         struct relay_viewer_stream *vstream = NULL;
1463         struct ctf_trace *ctf_trace;
1464         struct relay_viewer_stream *metadata_viewer_stream = NULL;
1465
1466         DBG2("Relay get data packet");
1467
1468         health_code_update();
1469
1470         ret = recv_request(conn->sock, &get_packet_info,
1471                         sizeof(get_packet_info));
1472         if (ret < 0) {
1473                 goto end;
1474         }
1475         health_code_update();
1476
1477         /* From this point on, the error label can be reached. */
1478         memset(&reply, 0, sizeof(reply));
1479
1480         vstream = viewer_stream_get_by_id(be64toh(get_packet_info.stream_id));
1481         if (!vstream) {
1482                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1483                 goto send_reply_nolock;
1484         }
1485
1486         ctf_trace = vstream->stream->trace;
1487
1488         /* metadata_viewer_stream may be NULL. */
1489         metadata_viewer_stream =
1490                         ctf_trace_get_viewer_metadata_stream(ctf_trace);
1491
1492         if (metadata_viewer_stream) {
1493                 bool get_packet_err = false;
1494
1495                 pthread_mutex_lock(&metadata_viewer_stream->stream->lock);
1496                 DBG("get packet metadata check: recv %" PRIu64 " sent %" PRIu64,
1497                         metadata_viewer_stream->stream->metadata_received,
1498                         metadata_viewer_stream->metadata_sent);
1499                 if (!metadata_viewer_stream->stream->metadata_received ||
1500                                 metadata_viewer_stream->stream->metadata_received >
1501                                         metadata_viewer_stream->metadata_sent) {
1502                         /*
1503                          * We prevent the client from reading a data stream as
1504                          * long as there is metadata left to consume. This
1505                          * ensures that the client won't receive data of which
1506                          * it can't make sense.
1507                          */
1508                         get_packet_err = true;
1509                 }
1510                 pthread_mutex_unlock(&metadata_viewer_stream->stream->lock);
1511                 viewer_stream_put(metadata_viewer_stream);
1512                 if (get_packet_err) {
1513                         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1514                         reply.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1515                         goto send_reply_nolock;
1516                 }
1517         }
1518
1519         pthread_mutex_lock(&vstream->stream->lock);
1520         /*
1521          * The vstream->stream_fd used here has been opened by
1522          * get_next_index. It is opened there because this is what
1523          * allows us to grab a reference to the file with stream lock
1524          * held, thus protecting us against overwrite caused by
1525          * tracefile rotation. Since tracefile rotation unlinks the old
1526          * data file, we are ensured that we won't have our data
1527          * overwritten under us.
1528          */
1529         ret = check_new_streams(conn);
1530         if (ret < 0) {
1531                 goto end_free;
1532         } else if (ret == 1) {
1533                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1534                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1535                 goto send_reply;
1536         }
1537
1538         len = be32toh(get_packet_info.len);
1539         data = zmalloc(len);
1540         if (!data) {
1541                 PERROR("relay data zmalloc");
1542                 goto error;
1543         }
1544
1545         ret = lseek(vstream->stream_fd->fd, be64toh(get_packet_info.offset),
1546                         SEEK_SET);
1547         if (ret < 0) {
1548                 PERROR("lseek fd %d to offset %" PRIu64, vstream->stream_fd->fd,
1549                         be64toh(get_packet_info.offset));
1550                 goto error;
1551         }
1552         read_len = lttng_read(vstream->stream_fd->fd, data, len);
1553         if (read_len < len) {
1554                 PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1555                                 vstream->stream_fd->fd,
1556                                 be64toh(get_packet_info.offset));
1557                 goto error;
1558         }
1559         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_OK);
1560         reply.len = htobe32(len);
1561         send_data = 1;
1562         goto send_reply;
1563
1564 error:
1565         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1566
1567 send_reply:
1568         if (vstream) {
1569                 pthread_mutex_unlock(&vstream->stream->lock);
1570         }
1571 send_reply_nolock:
1572         reply.flags = htobe32(reply.flags);
1573
1574         health_code_update();
1575
1576         ret = send_response(conn->sock, &reply, sizeof(reply));
1577         if (ret < 0) {
1578                 goto end_free;
1579         }
1580         health_code_update();
1581
1582         if (send_data) {
1583                 health_code_update();
1584                 ret = send_response(conn->sock, data, len);
1585                 if (ret < 0) {
1586                         goto end_free;
1587                 }
1588                 health_code_update();
1589         }
1590
1591         DBG("Sent %u bytes for stream %" PRIu64, len,
1592                         be64toh(get_packet_info.stream_id));
1593
1594 end_free:
1595         free(data);
1596 end:
1597         if (vstream) {
1598                 viewer_stream_put(vstream);
1599         }
1600         return ret;
1601 }
1602
1603 /*
1604  * Send the session's metadata
1605  *
1606  * Return 0 on success else a negative value.
1607  */
1608 static
1609 int viewer_get_metadata(struct relay_connection *conn)
1610 {
1611         int ret = 0;
1612         ssize_t read_len;
1613         uint64_t len = 0;
1614         char *data = NULL;
1615         struct lttng_viewer_get_metadata request;
1616         struct lttng_viewer_metadata_packet reply;
1617         struct relay_viewer_stream *vstream = NULL;
1618
1619         assert(conn);
1620
1621         DBG("Relay get metadata");
1622
1623         health_code_update();
1624
1625         ret = recv_request(conn->sock, &request, sizeof(request));
1626         if (ret < 0) {
1627                 goto end;
1628         }
1629         health_code_update();
1630
1631         memset(&reply, 0, sizeof(reply));
1632
1633         vstream = viewer_stream_get_by_id(be64toh(request.stream_id));
1634         if (!vstream) {
1635                 /*
1636                  * The metadata stream can be closed by a CLOSE command
1637                  * just before we attach. It can also be closed by
1638                  * per-pid tracing during tracing. Therefore, it is
1639                  * possible that we cannot find this viewer stream.
1640                  * Reply back to the client with an error if we cannot
1641                  * find it.
1642                  */
1643                 reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1644                 goto send_reply;
1645         }
1646         pthread_mutex_lock(&vstream->stream->lock);
1647         if (!vstream->stream->is_metadata) {
1648                 ERR("Invalid metadata stream");
1649                 goto error;
1650         }
1651
1652         assert(vstream->metadata_sent <= vstream->stream->metadata_received);
1653
1654         len = vstream->stream->metadata_received - vstream->metadata_sent;
1655         if (len == 0) {
1656                 reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
1657                 goto send_reply;
1658         }
1659
1660         /* first time, we open the metadata file */
1661         if (!vstream->stream_fd) {
1662                 char fullpath[PATH_MAX];
1663
1664                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", vstream->path_name,
1665                                 vstream->channel_name);
1666                 if (ret < 0) {
1667                         goto error;
1668                 }
1669                 ret = open(fullpath, O_RDONLY);
1670                 if (ret < 0) {
1671                         PERROR("Relay opening metadata file");
1672                         goto error;
1673                 }
1674                 vstream->stream_fd = stream_fd_create(ret);
1675                 if (!vstream->stream_fd) {
1676                         if (close(ret)) {
1677                                 PERROR("close");
1678                         }
1679                         goto error;
1680                 }
1681         }
1682
1683         reply.len = htobe64(len);
1684         data = zmalloc(len);
1685         if (!data) {
1686                 PERROR("viewer metadata zmalloc");
1687                 goto error;
1688         }
1689
1690         read_len = lttng_read(vstream->stream_fd->fd, data, len);
1691         if (read_len < len) {
1692                 PERROR("Relay reading metadata file");
1693                 goto error;
1694         }
1695         vstream->metadata_sent += read_len;
1696         if (vstream->metadata_sent == vstream->stream->metadata_received
1697                         && vstream->stream->closed) {
1698                 /* Release ownership for the viewer metadata stream. */
1699                 viewer_stream_put(vstream);
1700         }
1701
1702         reply.status = htobe32(LTTNG_VIEWER_METADATA_OK);
1703
1704         goto send_reply;
1705
1706 error:
1707         reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1708
1709 send_reply:
1710         health_code_update();
1711         if (vstream) {
1712                 pthread_mutex_unlock(&vstream->stream->lock);
1713         }
1714         ret = send_response(conn->sock, &reply, sizeof(reply));
1715         if (ret < 0) {
1716                 goto end_free;
1717         }
1718         health_code_update();
1719
1720         if (len > 0) {
1721                 ret = send_response(conn->sock, data, len);
1722                 if (ret < 0) {
1723                         goto end_free;
1724                 }
1725         }
1726
1727         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1728                         be64toh(request.stream_id));
1729
1730         DBG("Metadata sent");
1731
1732 end_free:
1733         free(data);
1734 end:
1735         if (vstream) {
1736                 viewer_stream_put(vstream);
1737         }
1738         return ret;
1739 }
1740
1741 /*
1742  * Create a viewer session.
1743  *
1744  * Return 0 on success or else a negative value.
1745  */
1746 static
1747 int viewer_create_session(struct relay_connection *conn)
1748 {
1749         int ret;
1750         struct lttng_viewer_create_session_response resp;
1751
1752         DBG("Viewer create session received");
1753
1754         memset(&resp, 0, sizeof(resp));
1755         resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_OK);
1756         conn->viewer_session = viewer_session_create();
1757         if (!conn->viewer_session) {
1758                 ERR("Allocation viewer session");
1759                 resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_ERR);
1760                 goto send_reply;
1761         }
1762
1763 send_reply:
1764         health_code_update();
1765         ret = send_response(conn->sock, &resp, sizeof(resp));
1766         if (ret < 0) {
1767                 goto end;
1768         }
1769         health_code_update();
1770         ret = 0;
1771
1772 end:
1773         return ret;
1774 }
1775
1776
1777 /*
1778  * live_relay_unknown_command: send -1 if received unknown command
1779  */
1780 static
1781 void live_relay_unknown_command(struct relay_connection *conn)
1782 {
1783         struct lttcomm_relayd_generic_reply reply;
1784
1785         memset(&reply, 0, sizeof(reply));
1786         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1787         (void) send_response(conn->sock, &reply, sizeof(reply));
1788 }
1789
1790 /*
1791  * Process the commands received on the control socket
1792  */
1793 static
1794 int process_control(struct lttng_viewer_cmd *recv_hdr,
1795                 struct relay_connection *conn)
1796 {
1797         int ret = 0;
1798         uint32_t msg_value;
1799
1800         msg_value = be32toh(recv_hdr->cmd);
1801
1802         /*
1803          * Make sure we've done the version check before any command other then a
1804          * new client connection.
1805          */
1806         if (msg_value != LTTNG_VIEWER_CONNECT && !conn->version_check_done) {
1807                 ERR("Viewer conn value %" PRIu32 " before version check", msg_value);
1808                 ret = -1;
1809                 goto end;
1810         }
1811
1812         switch (msg_value) {
1813         case LTTNG_VIEWER_CONNECT:
1814                 ret = viewer_connect(conn);
1815                 break;
1816         case LTTNG_VIEWER_LIST_SESSIONS:
1817                 ret = viewer_list_sessions(conn);
1818                 break;
1819         case LTTNG_VIEWER_ATTACH_SESSION:
1820                 ret = viewer_attach_session(conn);
1821                 break;
1822         case LTTNG_VIEWER_GET_NEXT_INDEX:
1823                 ret = viewer_get_next_index(conn);
1824                 break;
1825         case LTTNG_VIEWER_GET_PACKET:
1826                 ret = viewer_get_packet(conn);
1827                 break;
1828         case LTTNG_VIEWER_GET_METADATA:
1829                 ret = viewer_get_metadata(conn);
1830                 break;
1831         case LTTNG_VIEWER_GET_NEW_STREAMS:
1832                 ret = viewer_get_new_streams(conn);
1833                 break;
1834         case LTTNG_VIEWER_CREATE_SESSION:
1835                 ret = viewer_create_session(conn);
1836                 break;
1837         default:
1838                 ERR("Received unknown viewer command (%u)",
1839                                 be32toh(recv_hdr->cmd));
1840                 live_relay_unknown_command(conn);
1841                 ret = -1;
1842                 goto end;
1843         }
1844
1845 end:
1846         return ret;
1847 }
1848
1849 static
1850 void cleanup_connection_pollfd(struct lttng_poll_event *events, int pollfd)
1851 {
1852         int ret;
1853
1854         (void) lttng_poll_del(events, pollfd);
1855
1856         ret = close(pollfd);
1857         if (ret < 0) {
1858                 ERR("Closing pollfd %d", pollfd);
1859         }
1860 }
1861
1862 /*
1863  * This thread does the actual work
1864  */
1865 static
1866 void *thread_worker(void *data)
1867 {
1868         int ret, err = -1;
1869         uint32_t nb_fd;
1870         struct lttng_poll_event events;
1871         struct lttng_ht *viewer_connections_ht;
1872         struct lttng_ht_iter iter;
1873         struct lttng_viewer_cmd recv_hdr;
1874         struct relay_connection *destroy_conn;
1875
1876         DBG("[thread] Live viewer relay worker started");
1877
1878         rcu_register_thread();
1879
1880         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1881
1882         if (testpoint(relayd_thread_live_worker)) {
1883                 goto error_testpoint;
1884         }
1885
1886         /* table of connections indexed on socket */
1887         viewer_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1888         if (!viewer_connections_ht) {
1889                 goto viewer_connections_ht_error;
1890         }
1891
1892         ret = create_thread_poll_set(&events, 2);
1893         if (ret < 0) {
1894                 goto error_poll_create;
1895         }
1896
1897         ret = lttng_poll_add(&events, live_conn_pipe[0], LPOLLIN | LPOLLRDHUP);
1898         if (ret < 0) {
1899                 goto error;
1900         }
1901
1902 restart:
1903         while (1) {
1904                 int i;
1905
1906                 health_code_update();
1907
1908                 /* Infinite blocking call, waiting for transmission */
1909                 DBG3("Relayd live viewer worker thread polling...");
1910                 health_poll_entry();
1911                 ret = lttng_poll_wait(&events, -1);
1912                 health_poll_exit();
1913                 if (ret < 0) {
1914                         /*
1915                          * Restart interrupted system call.
1916                          */
1917                         if (errno == EINTR) {
1918                                 goto restart;
1919                         }
1920                         goto error;
1921                 }
1922
1923                 nb_fd = ret;
1924
1925                 /*
1926                  * Process control. The control connection is prioritised so we don't
1927                  * starve it with high throughput tracing data on the data
1928                  * connection.
1929                  */
1930                 for (i = 0; i < nb_fd; i++) {
1931                         /* Fetch once the poll data */
1932                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1933                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1934
1935                         health_code_update();
1936
1937                         if (!revents) {
1938                                 /* No activity for this FD (poll implementation). */
1939                                 continue;
1940                         }
1941
1942                         /* Thread quit pipe has been closed. Killing thread. */
1943                         ret = check_thread_quit_pipe(pollfd, revents);
1944                         if (ret) {
1945                                 err = 0;
1946                                 goto exit;
1947                         }
1948
1949                         /* Inspect the relay conn pipe for new connection. */
1950                         if (pollfd == live_conn_pipe[0]) {
1951                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1952                                         ERR("Relay live pipe error");
1953                                         goto error;
1954                                 } else if (revents & LPOLLIN) {
1955                                         struct relay_connection *conn;
1956
1957                                         ret = lttng_read(live_conn_pipe[0],
1958                                                         &conn, sizeof(conn));
1959                                         if (ret < 0) {
1960                                                 goto error;
1961                                         }
1962                                         lttng_poll_add(&events, conn->sock->fd,
1963                                                         LPOLLIN | LPOLLRDHUP);
1964                                         connection_ht_add(viewer_connections_ht, conn);
1965                                         DBG("Connection socket %d added to poll", conn->sock->fd);
1966                                 }
1967                         } else {
1968                                 /* Connection activity. */
1969                                 struct relay_connection *conn;
1970
1971                                 conn = connection_get_by_sock(viewer_connections_ht, pollfd);
1972                                 if (!conn) {
1973                                         continue;
1974                                 }
1975
1976                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1977                                         cleanup_connection_pollfd(&events, pollfd);
1978                                         /* Put "create" ownership reference. */
1979                                         connection_put(conn);
1980                                 } else if (revents & LPOLLIN) {
1981                                         ret = conn->sock->ops->recvmsg(conn->sock, &recv_hdr,
1982                                                         sizeof(recv_hdr), 0);
1983                                         if (ret <= 0) {
1984                                                 /* Connection closed. */
1985                                                 cleanup_connection_pollfd(&events, pollfd);
1986                                                 /* Put "create" ownership reference. */
1987                                                 connection_put(conn);
1988                                                 DBG("Viewer control conn closed with %d", pollfd);
1989                                         } else {
1990                                                 ret = process_control(&recv_hdr, conn);
1991                                                 if (ret < 0) {
1992                                                         /* Clear the session on error. */
1993                                                         cleanup_connection_pollfd(&events, pollfd);
1994                                                         /* Put "create" ownership reference. */
1995                                                         connection_put(conn);
1996                                                         DBG("Viewer connection closed with %d", pollfd);
1997                                                 }
1998                                         }
1999                                 }
2000                                 /* Put local "get_by_sock" reference. */
2001                                 connection_put(conn);
2002                         }
2003                 }
2004         }
2005
2006 exit:
2007 error:
2008         lttng_poll_clean(&events);
2009
2010         /* Cleanup reamaining connection object. */
2011         rcu_read_lock();
2012         cds_lfht_for_each_entry(viewer_connections_ht->ht, &iter.iter,
2013                         destroy_conn,
2014                         sock_n.node) {
2015                 health_code_update();
2016                 connection_put(destroy_conn);
2017         }
2018         rcu_read_unlock();
2019 error_poll_create:
2020         lttng_ht_destroy(viewer_connections_ht);
2021 viewer_connections_ht_error:
2022         /* Close relay conn pipes */
2023         utils_close_pipe(live_conn_pipe);
2024         if (err) {
2025                 DBG("Viewer worker thread exited with error");
2026         }
2027         DBG("Viewer worker thread cleanup complete");
2028 error_testpoint:
2029         if (err) {
2030                 health_error();
2031                 ERR("Health error occurred in %s", __func__);
2032         }
2033         health_unregister(health_relayd);
2034         if (lttng_relay_stop_threads()) {
2035                 ERR("Error stopping threads");
2036         }
2037         rcu_unregister_thread();
2038         return NULL;
2039 }
2040
2041 /*
2042  * Create the relay command pipe to wake thread_manage_apps.
2043  * Closed in cleanup().
2044  */
2045 static int create_conn_pipe(void)
2046 {
2047         return utils_create_pipe_cloexec(live_conn_pipe);
2048 }
2049
2050 int relayd_live_join(void)
2051 {
2052         int ret, retval = 0;
2053         void *status;
2054
2055         ret = pthread_join(live_listener_thread, &status);
2056         if (ret) {
2057                 errno = ret;
2058                 PERROR("pthread_join live listener");
2059                 retval = -1;
2060         }
2061
2062         ret = pthread_join(live_worker_thread, &status);
2063         if (ret) {
2064                 errno = ret;
2065                 PERROR("pthread_join live worker");
2066                 retval = -1;
2067         }
2068
2069         ret = pthread_join(live_dispatcher_thread, &status);
2070         if (ret) {
2071                 errno = ret;
2072                 PERROR("pthread_join live dispatcher");
2073                 retval = -1;
2074         }
2075
2076         cleanup_relayd_live();
2077
2078         return retval;
2079 }
2080
2081 /*
2082  * main
2083  */
2084 int relayd_live_create(struct lttng_uri *uri)
2085 {
2086         int ret = 0, retval = 0;
2087         void *status;
2088         int is_root;
2089
2090         if (!uri) {
2091                 retval = -1;
2092                 goto exit_init_data;
2093         }
2094         live_uri = uri;
2095
2096         /* Check if daemon is UID = 0 */
2097         is_root = !getuid();
2098
2099         if (!is_root) {
2100                 if (live_uri->port < 1024) {
2101                         ERR("Need to be root to use ports < 1024");
2102                         retval = -1;
2103                         goto exit_init_data;
2104                 }
2105         }
2106
2107         /* Setup the thread apps communication pipe. */
2108         if (create_conn_pipe()) {
2109                 retval = -1;
2110                 goto exit_init_data;
2111         }
2112
2113         /* Init relay command queue. */
2114         cds_wfcq_init(&viewer_conn_queue.head, &viewer_conn_queue.tail);
2115
2116         /* Set up max poll set size */
2117         if (lttng_poll_set_max_size()) {
2118                 retval = -1;
2119                 goto exit_init_data;
2120         }
2121
2122         /* Setup the dispatcher thread */
2123         ret = pthread_create(&live_dispatcher_thread, NULL,
2124                         thread_dispatcher, (void *) NULL);
2125         if (ret) {
2126                 errno = ret;
2127                 PERROR("pthread_create viewer dispatcher");
2128                 retval = -1;
2129                 goto exit_dispatcher_thread;
2130         }
2131
2132         /* Setup the worker thread */
2133         ret = pthread_create(&live_worker_thread, NULL,
2134                         thread_worker, NULL);
2135         if (ret) {
2136                 errno = ret;
2137                 PERROR("pthread_create viewer worker");
2138                 retval = -1;
2139                 goto exit_worker_thread;
2140         }
2141
2142         /* Setup the listener thread */
2143         ret = pthread_create(&live_listener_thread, NULL,
2144                         thread_listener, (void *) NULL);
2145         if (ret) {
2146                 errno = ret;
2147                 PERROR("pthread_create viewer listener");
2148                 retval = -1;
2149                 goto exit_listener_thread;
2150         }
2151
2152         /*
2153          * All OK, started all threads.
2154          */
2155         return retval;
2156
2157         /*
2158          * Join on the live_listener_thread should anything be added after
2159          * the live_listener thread's creation.
2160          */
2161
2162 exit_listener_thread:
2163
2164         ret = pthread_join(live_worker_thread, &status);
2165         if (ret) {
2166                 errno = ret;
2167                 PERROR("pthread_join live worker");
2168                 retval = -1;
2169         }
2170 exit_worker_thread:
2171
2172         ret = pthread_join(live_dispatcher_thread, &status);
2173         if (ret) {
2174                 errno = ret;
2175                 PERROR("pthread_join live dispatcher");
2176                 retval = -1;
2177         }
2178 exit_dispatcher_thread:
2179
2180 exit_init_data:
2181         cleanup_relayd_live();
2182
2183         return retval;
2184 }