src/bin/lttng-relayd/live.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #define _LGPL_SOURCE
  21 #include <getopt.h>
  22 #include <grp.h>
  23 #include <limits.h>
  24 #include <pthread.h>
  25 #include <signal.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <sys/mman.h>
  30 #include <sys/mount.h>
  31 #include <sys/resource.h>
  32 #include <sys/socket.h>
  33 #include <sys/stat.h>
  34 #include <sys/types.h>
  35 #include <sys/wait.h>
  36 #include <inttypes.h>
  37 #include <urcu/futex.h>
  38 #include <urcu/uatomic.h>
  39 #include <unistd.h>
  40 #include <fcntl.h>
  41 #include <config.h>
  42
  43 #include <lttng/lttng.h>
  44 #include <common/common.h>
  45 #include <common/compat/poll.h>
  46 #include <common/compat/socket.h>
  47 #include <common/compat/endian.h>
  48 #include <common/defaults.h>
  49 #include <common/futex.h>
  50 #include <common/index/index.h>
  51 #include <common/sessiond-comm/sessiond-comm.h>
  52 #include <common/sessiond-comm/inet.h>
  53 #include <common/sessiond-comm/relayd.h>
  54 #include <common/uri.h>
  55 #include <common/utils.h>
  56
  57 #include "cmd.h"
  58 #include "live.h"
  59 #include "lttng-relayd.h"
  60 #include "utils.h"
  61 #include "health-relayd.h"
  62 #include "testpoint.h"
  63 #include "viewer-stream.h"
  64 #include "stream.h"
  65 #include "session.h"
  66 #include "ctf-trace.h"
  67 #include "connection.h"
  68
  69 static struct lttng_uri *live_uri;
  70
  71 /*
  72  * This pipe is used to inform the worker thread that a command is queued and
  73  * ready to be processed.
  74  */
  75 static int live_conn_pipe[2] = { -1, -1 };
  76
  77 /* Shared between threads */
  78 static int live_dispatch_thread_exit;
  79
  80 static pthread_t live_listener_thread;
  81 static pthread_t live_dispatcher_thread;
  82 static pthread_t live_worker_thread;
  83
  84 /*
  85  * Relay command queue.
  86  *
  87  * The live_thread_listener and live_thread_dispatcher communicate with this
  88  * queue.
  89  */
  90 static struct relay_conn_queue viewer_conn_queue;
  91
  92 static uint64_t last_relay_viewer_session_id;
  93
  94 /*
  95  * Cleanup the daemon
  96  */
  97 static
  98 void cleanup_relayd_live(void)
  99 {
 100         DBG("Cleaning up");
 101
 102         free(live_uri);
 103 }
 104
 105 /*
 106  * Receive a request buffer using a given socket, destination allocated buffer
 107  * of length size.
 108  *
 109  * Return the size of the received message or else a negative value on error
 110  * with errno being set by recvmsg() syscall.
 111  */
 112 static
 113 ssize_t recv_request(struct lttcomm_sock *sock, void *buf, size_t size)
 114 {
 115         ssize_t ret;
 116
 117         assert(sock);
 118         assert(buf);
 119
 120         ret = sock->ops->recvmsg(sock, buf, size, 0);
 121         if (ret < 0 || ret != size) {
 122                 if (ret == 0) {
 123                         /* Orderly shutdown. Not necessary to print an error. */
 124                         DBG("Socket %d did an orderly shutdown", sock->fd);
 125                 } else {
 126                         ERR("Relay failed to receive request.");
 127                 }
 128                 ret = -1;
 129         }
 130
 131         return ret;
 132 }
 133
 134 /*
 135  * Send a response buffer using a given socket, source allocated buffer of
 136  * length size.
 137  *
 138  * Return the size of the sent message or else a negative value on error with
 139  * errno being set by sendmsg() syscall.
 140  */
 141 static
 142 ssize_t send_response(struct lttcomm_sock *sock, void *buf, size_t size)
 143 {
 144         ssize_t ret;
 145
 146         assert(sock);
 147         assert(buf);
 148
 149         ret = sock->ops->sendmsg(sock, buf, size, 0);
 150         if (ret < 0) {
 151                 ERR("Relayd failed to send response.");
 152         }
 153
 154         return ret;
 155 }
 156
 157 /*
 158  * Atomically check if new streams got added in one of the sessions attached
 159  * and reset the flag to 0.
 160  *
 161  * Returns 1 if new streams got added, 0 if nothing changed, a negative value
 162  * on error.
 163  */
 164 static
 165 int check_new_streams(struct relay_connection *conn)
 166 {
 167         struct relay_session *session;
 168         unsigned long current_val;
 169         int ret = 0;
 170
 171         if (!conn->viewer_session) {
 172                 goto end;
 173         }
 174         cds_list_for_each_entry(session,
 175                         &conn->viewer_session->sessions_head,
 176                         viewer_session_list) {
 177                 current_val = uatomic_cmpxchg(&session->new_streams, 1, 0);
 178                 ret = current_val;
 179                 if (ret == 1) {
 180                         goto end;
 181                 }
 182         }
 183
 184 end:
 185         return ret;
 186 }
 187
 188 /*
 189  * Send viewer streams to the given socket. The ignore_sent_flag indicates if
 190  * this function should ignore the sent flag or not.
 191  *
 192  * Return 0 on success or else a negative value.
 193  */
 194 static
 195 ssize_t send_viewer_streams(struct lttcomm_sock *sock,
 196                 struct relay_session *session, unsigned int ignore_sent_flag)
 197 {
 198         ssize_t ret;
 199         struct lttng_viewer_stream send_stream;
 200         struct lttng_ht_iter iter;
 201         struct relay_viewer_stream *vstream;
 202
 203         assert(session);
 204
 205         rcu_read_lock();
 206
 207         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
 208                         stream_n.node) {
 209                 struct ctf_trace *ctf_trace;
 210
 211                 health_code_update();
 212
 213                 /* Ignore if not the same session. */
 214                 if (vstream->session_id != session->id ||
 215                                 (!ignore_sent_flag && vstream->sent_flag)) {
 216                         continue;
 217                 }
 218
 219                 ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
 220                                 vstream->path_name);
 221                 assert(ctf_trace);
 222
 223                 send_stream.id = htobe64(vstream->stream_handle);
 224                 send_stream.ctf_trace_id = htobe64(ctf_trace->id);
 225                 send_stream.metadata_flag = htobe32(vstream->metadata_flag);
 226                 strncpy(send_stream.path_name, vstream->path_name,
 227                                 sizeof(send_stream.path_name));
 228                 strncpy(send_stream.channel_name, vstream->channel_name,
 229                                 sizeof(send_stream.channel_name));
 230
 231                 DBG("Sending stream %" PRIu64 " to viewer", vstream->stream_handle);
 232                 ret = send_response(sock, &send_stream, sizeof(send_stream));
 233                 if (ret < 0) {
 234                         goto end_unlock;
 235                 }
 236                 vstream->sent_flag = 1;
 237         }
 238
 239         ret = 0;
 240
 241 end_unlock:
 242         rcu_read_unlock();
 243         return ret;
 244 }
 245
 246 /*
 247  * Create every viewer stream possible for the given session with the seek
 248  * type. Three counters *can* be return which are in order the total amount of
 249  * viewer stream of the session, the number of unsent stream and the number of
 250  * stream created. Those counters can be NULL and thus will be ignored.
 251  *
 252  * Return 0 on success or else a negative value.
 253  */
 254 static
 255 int make_viewer_streams(struct relay_session *session,
 256                 enum lttng_viewer_seek seek_t, uint32_t *nb_total, uint32_t *nb_unsent,
 257                 uint32_t *nb_created)
 258 {
 259         int ret;
 260         struct lttng_ht_iter iter;
 261         struct ctf_trace *ctf_trace;
 262
 263         assert(session);
 264
 265         /*
 266          * This is to make sure we create viewer streams for a full received
 267          * channel. For instance, if we have 8 streams for a channel that are
 268          * concurrently being flagged ready, we can end up creating just a subset
 269          * of the 8 streams (the ones that are flagged). This lock avoids this
 270          * limbo state.
 271          */
 272         pthread_mutex_lock(&session->viewer_ready_lock);
 273
 274         /*
 275          * Create viewer streams for relay streams that are ready to be used for a
 276          * the given session id only.
 277          */
 278         rcu_read_lock();
 279         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 280                         node.node) {
 281                 struct relay_stream *stream;
 282
 283                 health_code_update();
 284
 285                 if (ctf_trace->invalid_flag) {
 286                         continue;
 287                 }
 288
 289                 cds_list_for_each_entry(stream, &ctf_trace->stream_list, trace_list) {
 290                         struct relay_viewer_stream *vstream;
 291
 292                         if (!stream->viewer_ready) {
 293                                 continue;
 294                         }
 295
 296                         vstream = viewer_stream_find_by_id(stream->stream_handle);
 297                         if (!vstream) {
 298                                 vstream = viewer_stream_create(stream, seek_t, ctf_trace);
 299                                 if (!vstream) {
 300                                         ret = -1;
 301                                         goto error_unlock;
 302                                 }
 303                                 /* Acquire reference to ctf_trace. */
 304                                 ctf_trace_get_ref(ctf_trace);
 305
 306                                 if (nb_created) {
 307                                         /* Update number of created stream counter. */
 308                                         (*nb_created)++;
 309                                 }
 310                         } else if (!vstream->sent_flag && nb_unsent) {
 311                                 /* Update number of unsent stream counter. */
 312                                 (*nb_unsent)++;
 313                         }
 314                         /* Update number of total stream counter. */
 315                         if (nb_total) {
 316                                 (*nb_total)++;
 317                         }
 318                 }
 319         }
 320
 321         ret = 0;
 322
 323 error_unlock:
 324         rcu_read_unlock();
 325         pthread_mutex_unlock(&session->viewer_ready_lock);
 326         return ret;
 327 }
 328
 329 /*
 330  * Write to writable pipe used to notify a thread.
 331  */
 332 static
 333 int notify_thread_pipe(int wpipe)
 334 {
 335         ssize_t ret;
 336
 337         ret = lttng_write(wpipe, "!", 1);
 338         if (ret < 1) {
 339                 PERROR("write poll pipe");
 340         }
 341
 342         return (int) ret;
 343 }
 344
 345 /*
 346  * Stop all threads by closing the thread quit pipe.
 347  */
 348 static
 349 int stop_threads(void)
 350 {
 351         int ret, retval = 0;
 352
 353         /* Stopping all threads */
 354         DBG("Terminating all live threads");
 355         ret = notify_thread_pipe(thread_quit_pipe[1]);
 356         if (ret < 0) {
 357                 ERR("write error on thread quit pipe");
 358                 retval = -1;
 359         }
 360
 361         /* Dispatch thread */
 362         CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
 363         futex_nto1_wake(&viewer_conn_queue.futex);
 364         return retval;
 365 }
 366
 367 /*
 368  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 369  */
 370 static
 371 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 372 {
 373         int ret;
 374
 375         if (events == NULL || size == 0) {
 376                 ret = -1;
 377                 goto error;
 378         }
 379
 380         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 381         if (ret < 0) {
 382                 goto error;
 383         }
 384
 385         /* Add quit pipe */
 386         ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
 387         if (ret < 0) {
 388                 goto error;
 389         }
 390
 391         return 0;
 392
 393 error:
 394         return ret;
 395 }
 396
 397 /*
 398  * Check if the thread quit pipe was triggered.
 399  *
 400  * Return 1 if it was triggered else 0;
 401  */
 402 static
 403 int check_thread_quit_pipe(int fd, uint32_t events)
 404 {
 405         if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
 406                 return 1;
 407         }
 408
 409         return 0;
 410 }
 411
 412 /*
 413  * Create and init socket from uri.
 414  */
 415 static
 416 struct lttcomm_sock *init_socket(struct lttng_uri *uri)
 417 {
 418         int ret;
 419         struct lttcomm_sock *sock = NULL;
 420
 421         sock = lttcomm_alloc_sock_from_uri(uri);
 422         if (sock == NULL) {
 423                 ERR("Allocating socket");
 424                 goto error;
 425         }
 426
 427         ret = lttcomm_create_sock(sock);
 428         if (ret < 0) {
 429                 goto error;
 430         }
 431         DBG("Listening on sock %d for live", sock->fd);
 432
 433         ret = sock->ops->bind(sock);
 434         if (ret < 0) {
 435                 goto error;
 436         }
 437
 438         ret = sock->ops->listen(sock, -1);
 439         if (ret < 0) {
 440                 goto error;
 441
 442         }
 443
 444         return sock;
 445
 446 error:
 447         if (sock) {
 448                 lttcomm_destroy_sock(sock);
 449         }
 450         return NULL;
 451 }
 452
 453 /*
 454  * This thread manages the listening for new connections on the network
 455  */
 456 static
 457 void *thread_listener(void *data)
 458 {
 459         int i, ret, pollfd, err = -1;
 460         uint32_t revents, nb_fd;
 461         struct lttng_poll_event events;
 462         struct lttcomm_sock *live_control_sock;
 463
 464         DBG("[thread] Relay live listener started");
 465
 466         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_LISTENER);
 467
 468         health_code_update();
 469
 470         live_control_sock = init_socket(live_uri);
 471         if (!live_control_sock) {
 472                 goto error_sock_control;
 473         }
 474
 475         /* Pass 2 as size here for the thread quit pipe and control sockets. */
 476         ret = create_thread_poll_set(&events, 2);
 477         if (ret < 0) {
 478                 goto error_create_poll;
 479         }
 480
 481         /* Add the control socket */
 482         ret = lttng_poll_add(&events, live_control_sock->fd, LPOLLIN | LPOLLRDHUP);
 483         if (ret < 0) {
 484                 goto error_poll_add;
 485         }
 486
 487         lttng_relay_notify_ready();
 488
 489         if (testpoint(relayd_thread_live_listener)) {
 490                 goto error_testpoint;
 491         }
 492
 493         while (1) {
 494                 health_code_update();
 495
 496                 DBG("Listener accepting live viewers connections");
 497
 498 restart:
 499                 health_poll_entry();
 500                 ret = lttng_poll_wait(&events, -1);
 501                 health_poll_exit();
 502                 if (ret < 0) {
 503                         /*
 504                          * Restart interrupted system call.
 505                          */
 506                         if (errno == EINTR) {
 507                                 goto restart;
 508                         }
 509                         goto error;
 510                 }
 511                 nb_fd = ret;
 512
 513                 DBG("Relay new viewer connection received");
 514                 for (i = 0; i < nb_fd; i++) {
 515                         health_code_update();
 516
 517                         /* Fetch once the poll data */
 518                         revents = LTTNG_POLL_GETEV(&events, i);
 519                         pollfd = LTTNG_POLL_GETFD(&events, i);
 520
 521                         /* Thread quit pipe has been closed. Killing thread. */
 522                         ret = check_thread_quit_pipe(pollfd, revents);
 523                         if (ret) {
 524                                 err = 0;
 525                                 goto exit;
 526                         }
 527
 528                         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 529                                 ERR("socket poll error");
 530                                 goto error;
 531                         } else if (revents & LPOLLIN) {
 532                                 /*
 533                                  * Get allocated in this thread, enqueued to a global queue,
 534                                  * dequeued and freed in the worker thread.
 535                                  */
 536                                 int val = 1;
 537                                 struct relay_connection *new_conn;
 538                                 struct lttcomm_sock *newsock;
 539
 540                                 new_conn = connection_create();
 541                                 if (!new_conn) {
 542                                         goto error;
 543                                 }
 544
 545                                 newsock = live_control_sock->ops->accept(live_control_sock);
 546                                 if (!newsock) {
 547                                         PERROR("accepting control sock");
 548                                         connection_free(new_conn);
 549                                         goto error;
 550                                 }
 551                                 DBG("Relay viewer connection accepted socket %d", newsock->fd);
 552
 553                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR, &val,
 554                                                 sizeof(val));
 555                                 if (ret < 0) {
 556                                         PERROR("setsockopt inet");
 557                                         lttcomm_destroy_sock(newsock);
 558                                         connection_free(new_conn);
 559                                         goto error;
 560                                 }
 561                                 new_conn->sock = newsock;
 562
 563                                 /* Enqueue request for the dispatcher thread. */
 564                                 cds_wfcq_enqueue(&viewer_conn_queue.head, &viewer_conn_queue.tail,
 565                                                  &new_conn->qnode);
 566
 567                                 /*
 568                                  * Wake the dispatch queue futex. Implicit memory barrier with
 569                                  * the exchange in cds_wfcq_enqueue.
 570                                  */
 571                                 futex_nto1_wake(&viewer_conn_queue.futex);
 572                         }
 573                 }
 574         }
 575
 576 exit:
 577 error:
 578 error_poll_add:
 579 error_testpoint:
 580         lttng_poll_clean(&events);
 581 error_create_poll:
 582         if (live_control_sock->fd >= 0) {
 583                 ret = live_control_sock->ops->close(live_control_sock);
 584                 if (ret) {
 585                         PERROR("close");
 586                 }
 587         }
 588         lttcomm_destroy_sock(live_control_sock);
 589 error_sock_control:
 590         if (err) {
 591                 health_error();
 592                 DBG("Live viewer listener thread exited with error");
 593         }
 594         health_unregister(health_relayd);
 595         DBG("Live viewer listener thread cleanup complete");
 596         if (stop_threads()) {
 597                 ERR("Error stopping live threads");
 598         }
 599         return NULL;
 600 }
 601
 602 /*
 603  * This thread manages the dispatching of the requests to worker threads
 604  */
 605 static
 606 void *thread_dispatcher(void *data)
 607 {
 608         int err = -1;
 609         ssize_t ret;
 610         struct cds_wfcq_node *node;
 611         struct relay_connection *conn = NULL;
 612
 613         DBG("[thread] Live viewer relay dispatcher started");
 614
 615         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 616
 617         if (testpoint(relayd_thread_live_dispatcher)) {
 618                 goto error_testpoint;
 619         }
 620
 621         health_code_update();
 622
 623         while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 624                 health_code_update();
 625
 626                 /* Atomically prepare the queue futex */
 627                 futex_nto1_prepare(&viewer_conn_queue.futex);
 628
 629                 do {
 630                         health_code_update();
 631
 632                         /* Dequeue commands */
 633                         node = cds_wfcq_dequeue_blocking(&viewer_conn_queue.head,
 634                                                          &viewer_conn_queue.tail);
 635                         if (node == NULL) {
 636                                 DBG("Woken up but nothing in the live-viewer "
 637                                                 "relay command queue");
 638                                 /* Continue thread execution */
 639                                 break;
 640                         }
 641                         conn = caa_container_of(node, struct relay_connection, qnode);
 642                         DBG("Dispatching viewer request waiting on sock %d",
 643                                         conn->sock->fd);
 644
 645                         /*
 646                          * Inform worker thread of the new request. This call is blocking
 647                          * so we can be assured that the data will be read at some point in
 648                          * time or wait to the end of the world :)
 649                          */
 650                         ret = lttng_write(live_conn_pipe[1], &conn, sizeof(conn));
 651                         if (ret < 0) {
 652                                 PERROR("write conn pipe");
 653                                 connection_destroy(conn);
 654                                 goto error;
 655                         }
 656                 } while (node != NULL);
 657
 658                 /* Futex wait on queue. Blocking call on futex() */
 659                 health_poll_entry();
 660                 futex_nto1_wait(&viewer_conn_queue.futex);
 661                 health_poll_exit();
 662         }
 663
 664         /* Normal exit, no error */
 665         err = 0;
 666
 667 error:
 668 error_testpoint:
 669         if (err) {
 670                 health_error();
 671                 ERR("Health error occurred in %s", __func__);
 672         }
 673         health_unregister(health_relayd);
 674         DBG("Live viewer dispatch thread dying");
 675         if (stop_threads()) {
 676                 ERR("Error stopping live threads");
 677         }
 678         return NULL;
 679 }
 680
 681 /*
 682  * Establish connection with the viewer and check the versions.
 683  *
 684  * Return 0 on success or else negative value.
 685  */
 686 static
 687 int viewer_connect(struct relay_connection *conn)
 688 {
 689         int ret;
 690         struct lttng_viewer_connect reply, msg;
 691
 692         assert(conn);
 693
 694         conn->version_check_done = 1;
 695
 696         health_code_update();
 697
 698         DBG("Viewer is establishing a connection to the relayd.");
 699
 700         ret = recv_request(conn->sock, &msg, sizeof(msg));
 701         if (ret < 0) {
 702                 goto end;
 703         }
 704
 705         health_code_update();
 706
 707         memset(&reply, 0, sizeof(reply));
 708         reply.major = RELAYD_VERSION_COMM_MAJOR;
 709         reply.minor = RELAYD_VERSION_COMM_MINOR;
 710
 711         /* Major versions must be the same */
 712         if (reply.major != be32toh(msg.major)) {
 713                 DBG("Incompatible major versions ([relayd] %u vs [client] %u)",
 714                                 reply.major, be32toh(msg.major));
 715                 ret = -1;
 716                 goto end;
 717         }
 718
 719         conn->major = reply.major;
 720         /* We adapt to the lowest compatible version */
 721         if (reply.minor <= be32toh(msg.minor)) {
 722                 conn->minor = reply.minor;
 723         } else {
 724                 conn->minor = be32toh(msg.minor);
 725         }
 726
 727         if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_COMMAND) {
 728                 conn->type = RELAY_VIEWER_COMMAND;
 729         } else if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_NOTIFICATION) {
 730                 conn->type = RELAY_VIEWER_NOTIFICATION;
 731         } else {
 732                 ERR("Unknown connection type : %u", be32toh(msg.type));
 733                 ret = -1;
 734                 goto end;
 735         }
 736
 737         reply.major = htobe32(reply.major);
 738         reply.minor = htobe32(reply.minor);
 739         if (conn->type == RELAY_VIEWER_COMMAND) {
 740                 reply.viewer_session_id = htobe64(++last_relay_viewer_session_id);
 741         }
 742
 743         health_code_update();
 744
 745         ret = send_response(conn->sock, &reply, sizeof(reply));
 746         if (ret < 0) {
 747                 goto end;
 748         }
 749
 750         health_code_update();
 751
 752         DBG("Version check done using protocol %u.%u", conn->major, conn->minor);
 753         ret = 0;
 754
 755 end:
 756         return ret;
 757 }
 758
 759 /*
 760  * Send the viewer the list of current sessions.
 761  *
 762  * Return 0 on success or else a negative value.
 763  */
 764 static
 765 int viewer_list_sessions(struct relay_connection *conn)
 766 {
 767         int ret;
 768         struct lttng_viewer_list_sessions session_list;
 769         unsigned long count;
 770         long approx_before, approx_after;
 771         struct lttng_ht_iter iter;
 772         struct lttng_viewer_session send_session;
 773         struct relay_session *session;
 774
 775         DBG("List sessions received");
 776
 777         rcu_read_lock();
 778         cds_lfht_count_nodes(conn->sessions_ht->ht, &approx_before, &count,
 779                         &approx_after);
 780         session_list.sessions_count = htobe32(count);
 781
 782         health_code_update();
 783
 784         ret = send_response(conn->sock, &session_list, sizeof(session_list));
 785         if (ret < 0) {
 786                 goto end_unlock;
 787         }
 788
 789         health_code_update();
 790
 791         cds_lfht_for_each_entry(conn->sessions_ht->ht, &iter.iter, session,
 792                         session_n.node) {
 793                 health_code_update();
 794
 795                 strncpy(send_session.session_name, session->session_name,
 796                                 sizeof(send_session.session_name));
 797                 strncpy(send_session.hostname, session->hostname,
 798                                 sizeof(send_session.hostname));
 799                 send_session.id = htobe64(session->id);
 800                 send_session.live_timer = htobe32(session->live_timer);
 801                 send_session.clients = htobe32(session->viewer_refcount);
 802                 send_session.streams = htobe32(session->stream_count);
 803
 804                 health_code_update();
 805
 806                 ret = send_response(conn->sock, &send_session, sizeof(send_session));
 807                 if (ret < 0) {
 808                         goto end_unlock;
 809                 }
 810         }
 811         health_code_update();
 812
 813         ret = 0;
 814 end_unlock:
 815         rcu_read_unlock();
 816         return ret;
 817 }
 818
 819 /*
 820  * Check if a connection is attached to a session.
 821  * Return 1 if attached, 0 if not attached, a negative value on error.
 822  */
 823 static
 824 int session_attached(struct relay_connection *conn, uint64_t session_id)
 825 {
 826         struct relay_session *session;
 827         int found = 0;
 828
 829         if (!conn->viewer_session) {
 830                 goto end;
 831         }
 832         cds_list_for_each_entry(session,
 833                         &conn->viewer_session->sessions_head,
 834                         viewer_session_list) {
 835                 if (session->id == session_id) {
 836                         found = 1;
 837                         goto end;
 838                 }
 839         }
 840
 841 end:
 842         return found;
 843 }
 844
 845 /*
 846  * Delete all streams for a specific session ID.
 847  */
 848 static void destroy_viewer_streams_by_session(struct relay_session *session)
 849 {
 850         struct relay_viewer_stream *stream;
 851         struct lttng_ht_iter iter;
 852
 853         assert(session);
 854
 855         rcu_read_lock();
 856         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, stream,
 857                         stream_n.node) {
 858                 struct ctf_trace *ctf_trace;
 859
 860                 health_code_update();
 861                 if (stream->session_id != session->id) {
 862                         continue;
 863                 }
 864
 865                 ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
 866                                 stream->path_name);
 867                 assert(ctf_trace);
 868
 869                 viewer_stream_delete(stream);
 870
 871                 if (stream->metadata_flag) {
 872                         ctf_trace->metadata_sent = 0;
 873                         ctf_trace->viewer_metadata_stream = NULL;
 874                 }
 875
 876                 viewer_stream_destroy(ctf_trace, stream);
 877         }
 878         rcu_read_unlock();
 879 }
 880
 881 static void try_destroy_streams(struct relay_session *session)
 882 {
 883         struct ctf_trace *ctf_trace;
 884         struct lttng_ht_iter iter;
 885
 886         assert(session);
 887
 888         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 889                         node.node) {
 890                 /* Attempt to destroy the ctf trace of that session. */
 891                 ctf_trace_try_destroy(session, ctf_trace);
 892         }
 893 }
 894
 895 /*
 896  * Cleanup a session.
 897  */
 898 static void cleanup_session(struct relay_connection *conn,
 899                 struct relay_session *session)
 900 {
 901         /*
 902          * Very important that this is done before destroying the session so we
 903          * can put back every viewer stream reference from the ctf_trace.
 904          */
 905         destroy_viewer_streams_by_session(session);
 906         try_destroy_streams(session);
 907         cds_list_del(&session->viewer_session_list);
 908         session_viewer_try_destroy(conn->sessions_ht, session);
 909 }
 910
 911 /*
 912  * Send the viewer the list of current sessions.
 913  */
 914 static
 915 int viewer_get_new_streams(struct relay_connection *conn)
 916 {
 917         int ret, send_streams = 0;
 918         uint32_t nb_created = 0, nb_unsent = 0, nb_streams = 0;
 919         struct lttng_viewer_new_streams_request request;
 920         struct lttng_viewer_new_streams_response response;
 921         struct relay_session *session;
 922         uint64_t session_id;
 923
 924         assert(conn);
 925
 926         DBG("Get new streams received");
 927
 928         health_code_update();
 929
 930         /* Receive the request from the connected client. */
 931         ret = recv_request(conn->sock, &request, sizeof(request));
 932         if (ret < 0) {
 933                 goto error;
 934         }
 935         session_id = be64toh(request.session_id);
 936
 937         health_code_update();
 938
 939         memset(&response, 0, sizeof(response));
 940
 941         rcu_read_lock();
 942         session = session_find_by_id(conn->sessions_ht, session_id);
 943         if (!session) {
 944                 DBG("Relay session %" PRIu64 " not found", session_id);
 945                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 946                 goto send_reply;
 947         }
 948
 949         if (!session_attached(conn, session_id)) {
 950                 send_streams = 0;
 951                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 952                 goto send_reply;
 953         }
 954
 955         send_streams = 1;
 956         response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 957
 958         ret = make_viewer_streams(session, LTTNG_VIEWER_SEEK_LAST, NULL, &nb_unsent,
 959                         &nb_created);
 960         if (ret < 0) {
 961                 goto end_unlock;
 962         }
 963         /* Only send back the newly created streams with the unsent ones. */
 964         nb_streams = nb_created + nb_unsent;
 965         response.streams_count = htobe32(nb_streams);
 966
 967         /*
 968          * If the session is closed and we have no new streams to send,
 969          * it means that the viewer has already received the whole trace
 970          * for this session and should now close it.
 971          */
 972         if (nb_streams == 0 && session->close_flag) {
 973                 send_streams = 0;
 974                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
 975                 /*
 976                  * Remove the session from the attached list of the connection
 977                  * and try to destroy it.
 978                  */
 979                 cds_list_del(&session->viewer_session_list);
 980                 cleanup_session(conn, session);
 981                 goto send_reply;
 982         }
 983
 984 send_reply:
 985         health_code_update();
 986         ret = send_response(conn->sock, &response, sizeof(response));
 987         if (ret < 0) {
 988                 goto end_unlock;
 989         }
 990         health_code_update();
 991
 992         /*
 993          * Unknown or empty session, just return gracefully, the viewer knows what
 994          * is happening.
 995          */
 996         if (!send_streams || !nb_streams) {
 997                 ret = 0;
 998                 goto end_unlock;
 999         }
1000
1001         /*
1002          * Send stream and *DON'T* ignore the sent flag so every viewer streams
1003          * that were not sent from that point will be sent to the viewer.
1004          */
1005         ret = send_viewer_streams(conn->sock, session, 0);
1006         if (ret < 0) {
1007                 goto end_unlock;
1008         }
1009
1010 end_unlock:
1011         rcu_read_unlock();
1012 error:
1013         return ret;
1014 }
1015
1016 /*
1017  * Send the viewer the list of current sessions.
1018  */
1019 static
1020 int viewer_attach_session(struct relay_connection *conn)
1021 {
1022         int send_streams = 0;
1023         ssize_t ret;
1024         uint32_t nb_streams = 0;
1025         enum lttng_viewer_seek seek_type;
1026         struct lttng_viewer_attach_session_request request;
1027         struct lttng_viewer_attach_session_response response;
1028         struct relay_session *session;
1029
1030         assert(conn);
1031
1032         health_code_update();
1033
1034         /* Receive the request from the connected client. */
1035         ret = recv_request(conn->sock, &request, sizeof(request));
1036         if (ret < 0) {
1037                 goto error;
1038         }
1039
1040         health_code_update();
1041
1042         memset(&response, 0, sizeof(response));
1043
1044         if (!conn->viewer_session) {
1045                 DBG("Client trying to attach before creating a live viewer session");
1046                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NO_SESSION);
1047                 goto send_reply;
1048         }
1049
1050         rcu_read_lock();
1051         session = session_find_by_id(conn->sessions_ht,
1052                         be64toh(request.session_id));
1053         if (!session) {
1054                 DBG("Relay session %" PRIu64 " not found",
1055                                 be64toh(request.session_id));
1056                 response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
1057                 goto send_reply;
1058         }
1059         session_viewer_attach(session);
1060         DBG("Attach session ID %" PRIu64 " received", be64toh(request.session_id));
1061
1062         if (uatomic_read(&session->viewer_refcount) > 1) {
1063                 DBG("Already a viewer attached");
1064                 response.status = htobe32(LTTNG_VIEWER_ATTACH_ALREADY);
1065                 session_viewer_detach(session);
1066                 goto send_reply;
1067         } else if (session->live_timer == 0) {
1068                 DBG("Not live session");
1069                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NOT_LIVE);
1070                 goto send_reply;
1071         } else {
1072                 send_streams = 1;
1073                 response.status = htobe32(LTTNG_VIEWER_ATTACH_OK);
1074                 cds_list_add(&session->viewer_session_list,
1075                                 &conn->viewer_session->sessions_head);
1076         }
1077
1078         switch (be32toh(request.seek)) {
1079         case LTTNG_VIEWER_SEEK_BEGINNING:
1080         case LTTNG_VIEWER_SEEK_LAST:
1081                 seek_type = be32toh(request.seek);
1082                 break;
1083         default:
1084                 ERR("Wrong seek parameter");
1085                 response.status = htobe32(LTTNG_VIEWER_ATTACH_SEEK_ERR);
1086                 send_streams = 0;
1087                 goto send_reply;
1088         }
1089
1090         ret = make_viewer_streams(session, seek_type, &nb_streams, NULL, NULL);
1091         if (ret < 0) {
1092                 goto end_unlock;
1093         }
1094         response.streams_count = htobe32(nb_streams);
1095
1096 send_reply:
1097         health_code_update();
1098         ret = send_response(conn->sock, &response, sizeof(response));
1099         if (ret < 0) {
1100                 goto end_unlock;
1101         }
1102         health_code_update();
1103
1104         /*
1105          * Unknown or empty session, just return gracefully, the viewer knows what
1106          * is happening.
1107          */
1108         if (!send_streams || !nb_streams) {
1109                 ret = 0;
1110                 goto end_unlock;
1111         }
1112
1113         /* Send stream and ignore the sent flag. */
1114         ret = send_viewer_streams(conn->sock, session, 1);
1115         if (ret < 0) {
1116                 goto end_unlock;
1117         }
1118
1119 end_unlock:
1120         rcu_read_unlock();
1121 error:
1122         return ret;
1123 }
1124
1125 /*
1126  * Open the index file if needed for the given vstream.
1127  *
1128  * If an index file is successfully opened, the index_read_fd of the stream is
1129  * set with it.
1130  *
1131  * Return 0 on success, a negative value on error (-ENOENT if not ready yet).
1132  */
1133 static int try_open_index(struct relay_viewer_stream *vstream,
1134                 struct relay_stream *rstream)
1135 {
1136         int ret = 0;
1137
1138         assert(vstream);
1139         assert(rstream);
1140
1141         if (vstream->index_read_fd >= 0) {
1142                 goto end;
1143         }
1144
1145         /*
1146          * First time, we open the index file and at least one index is ready.  The
1147          * race between the read and write of the total_index_received is
1148          * acceptable here since the client will be notified to simply come back
1149          * and get the next index.
1150          */
1151         if (rstream->total_index_received <= 0) {
1152                 ret = -ENOENT;
1153                 goto end;
1154         }
1155         ret = index_open(vstream->path_name, vstream->channel_name,
1156                         vstream->tracefile_count, vstream->tracefile_count_current);
1157         if (ret >= 0) {
1158                 vstream->index_read_fd = ret;
1159                 ret = 0;
1160                 goto end;
1161         }
1162
1163 end:
1164         return ret;
1165 }
1166
1167 /*
1168  * Check the status of the index for the given stream. This function updates
1169  * the index structure if needed and can destroy the vstream also for the HUP
1170  * situation.
1171  *
1172  * Return 0 means that we can proceed with the index. A value of 1 means that
1173  * the index has been updated and is ready to be send to the client. A negative
1174  * value indicates an error that can't be handled.
1175  */
1176 static int check_index_status(struct relay_viewer_stream *vstream,
1177                 struct relay_stream *rstream, struct ctf_trace *trace,
1178                 struct lttng_viewer_index *index)
1179 {
1180         int ret;
1181
1182         assert(vstream);
1183         assert(rstream);
1184         assert(index);
1185         assert(trace);
1186
1187         if (!rstream->close_flag) {
1188                 /* Rotate on abort (overwrite). */
1189                 if (vstream->abort_flag) {
1190                         DBG("Viewer stream %" PRIu64 " rotate because of overwrite",
1191                                         vstream->stream_handle);
1192                         ret = viewer_stream_rotate(vstream, rstream);
1193                         if (ret < 0) {
1194                                 goto error;
1195                         } else if (ret == 1) {
1196                                 /* EOF */
1197                                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1198                                 goto hup;
1199                         }
1200                         /* ret == 0 means successful so we continue. */
1201                 }
1202
1203                 /* Check if we are in the same trace file at this point. */
1204                 if (rstream->tracefile_count_current == vstream->tracefile_count_current) {
1205                         if (rstream->beacon_ts_end != -1ULL &&
1206                                         vstream->last_sent_index == rstream->total_index_received) {
1207                                 /*
1208                                  * We've received a synchronization beacon and the last index
1209                                  * available has been sent, the index for now is inactive.
1210                                  */
1211                                 index->status = htobe32(LTTNG_VIEWER_INDEX_INACTIVE);
1212                                 index->timestamp_end = htobe64(rstream->beacon_ts_end);
1213                                 index->stream_id = htobe64(rstream->ctf_stream_id);
1214                                 goto index_ready;
1215                         } else if (rstream->total_index_received <= vstream->last_sent_index
1216                                         && !vstream->close_write_flag) {
1217                                 /*
1218                                  * Reader and writer are working in the same tracefile, so we care
1219                                  * about the number of index received and sent. Otherwise, we read
1220                                  * up to EOF.
1221                                  */
1222                                 index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1223                                 goto index_ready;
1224                         }
1225                 }
1226                 /* Nothing to do with the index, continue with it. */
1227                 ret = 0;
1228         } else if (rstream->close_flag && vstream->close_write_flag &&
1229                         vstream->total_index_received == vstream->last_sent_index) {
1230                 /* Last index sent and current tracefile closed in write */
1231                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1232                 goto hup;
1233         } else {
1234                 vstream->close_write_flag = 1;
1235                 ret = 0;
1236         }
1237
1238 error:
1239         return ret;
1240
1241 hup:
1242         viewer_stream_delete(vstream);
1243         viewer_stream_destroy(trace, vstream);
1244 index_ready:
1245         return 1;
1246 }
1247
1248 /*
1249  * Send the next index for a stream.
1250  *
1251  * Return 0 on success or else a negative value.
1252  */
1253 static
1254 int viewer_get_next_index(struct relay_connection *conn)
1255 {
1256         int ret;
1257         ssize_t read_ret;
1258         struct lttng_viewer_get_next_index request_index;
1259         struct lttng_viewer_index viewer_index;
1260         struct ctf_packet_index packet_index;
1261         struct relay_viewer_stream *vstream;
1262         struct relay_stream *rstream;
1263         struct ctf_trace *ctf_trace;
1264         struct relay_session *session;
1265
1266         assert(conn);
1267
1268         DBG("Viewer get next index");
1269
1270         health_code_update();
1271
1272         ret = recv_request(conn->sock, &request_index, sizeof(request_index));
1273         if (ret < 0) {
1274                 goto end;
1275         }
1276         health_code_update();
1277
1278         rcu_read_lock();
1279         vstream = viewer_stream_find_by_id(be64toh(request_index.stream_id));
1280         if (!vstream) {
1281                 ret = -1;
1282                 goto end_unlock;
1283         }
1284
1285         session = session_find_by_id(conn->sessions_ht, vstream->session_id);
1286         if (!session) {
1287                 ret = -1;
1288                 goto end_unlock;
1289         }
1290
1291         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht, vstream->path_name);
1292         assert(ctf_trace);
1293
1294         memset(&viewer_index, 0, sizeof(viewer_index));
1295
1296         /*
1297          * The viewer should not ask for index on metadata stream.
1298          */
1299         if (vstream->metadata_flag) {
1300                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1301                 goto send_reply;
1302         }
1303
1304         rstream = stream_find_by_id(relay_streams_ht, vstream->stream_handle);
1305         assert(rstream);
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 packet arrives, it
1313                          * might not be ready at the beginning of the session
1314                          */
1315                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1316                 } else {
1317                         /* Unhandled error. */
1318                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1319                 }
1320                 goto send_reply;
1321         }
1322
1323         pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1324         ret = check_index_status(vstream, rstream, ctf_trace, &viewer_index);
1325         pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1326         if (ret < 0) {
1327                 goto end_unlock;
1328         } else if (ret == 1) {
1329                 /*
1330                  * This means the viewer index data structure has been populated by the
1331                  * check call thus we now send back the reply to the client.
1332                  */
1333                 goto send_reply;
1334         }
1335         /* At this point, ret MUST be 0 thus we continue with the get. */
1336         assert(!ret);
1337
1338         if (!ctf_trace->metadata_received ||
1339                         ctf_trace->metadata_received > ctf_trace->metadata_sent) {
1340                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1341         }
1342
1343         ret = check_new_streams(conn);
1344         if (ret < 0) {
1345                 goto end_unlock;
1346         } else if (ret == 1) {
1347                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1348         }
1349
1350         pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1351         pthread_mutex_lock(&vstream->overwrite_lock);
1352         if (vstream->abort_flag) {
1353                 /* The file is being overwritten by the writer, we cannot use it. */
1354                 pthread_mutex_unlock(&vstream->overwrite_lock);
1355                 ret = viewer_stream_rotate(vstream, rstream);
1356                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1357                 if (ret < 0) {
1358                         goto end_unlock;
1359                 } else if (ret == 1) {
1360                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1361                         viewer_stream_delete(vstream);
1362                         viewer_stream_destroy(ctf_trace, vstream);
1363                 } else {
1364                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1365                 }
1366                 goto send_reply;
1367         }
1368
1369         read_ret = lttng_read(vstream->index_read_fd, &packet_index,
1370                         sizeof(packet_index));
1371         pthread_mutex_unlock(&vstream->overwrite_lock);
1372         pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1373         if (read_ret < 0) {
1374                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1375                 viewer_stream_delete(vstream);
1376                 viewer_stream_destroy(ctf_trace, vstream);
1377                 goto send_reply;
1378         } else if (read_ret < sizeof(packet_index)) {
1379                 pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1380                 if (vstream->close_write_flag) {
1381                         ret = viewer_stream_rotate(vstream, rstream);
1382                         if (ret < 0) {
1383                                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1384                                 goto end_unlock;
1385                         } else if (ret == 1) {
1386                                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1387                                 viewer_stream_delete(vstream);
1388                                 viewer_stream_destroy(ctf_trace, vstream);
1389                         } else {
1390                                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1391                         }
1392                 } else {
1393                         ERR("Relay reading index file %d", vstream->index_read_fd);
1394                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1395                 }
1396                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1397                 goto send_reply;
1398         } else {
1399                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_OK);
1400                 vstream->last_sent_index++;
1401         }
1402
1403         /*
1404          * Indexes are stored in big endian, no need to switch before sending.
1405          */
1406         viewer_index.offset = packet_index.offset;
1407         viewer_index.packet_size = packet_index.packet_size;
1408         viewer_index.content_size = packet_index.content_size;
1409         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1410         viewer_index.timestamp_end = packet_index.timestamp_end;
1411         viewer_index.events_discarded = packet_index.events_discarded;
1412         viewer_index.stream_id = packet_index.stream_id;
1413
1414 send_reply:
1415         viewer_index.flags = htobe32(viewer_index.flags);
1416         health_code_update();
1417
1418         ret = send_response(conn->sock, &viewer_index, sizeof(viewer_index));
1419         if (ret < 0) {
1420                 goto end_unlock;
1421         }
1422         health_code_update();
1423
1424         DBG("Index %" PRIu64 " for stream %" PRIu64 " sent",
1425                         vstream->last_sent_index, vstream->stream_handle);
1426
1427 end_unlock:
1428         rcu_read_unlock();
1429
1430 end:
1431         return ret;
1432 }
1433
1434 /*
1435  * Send the next index for a stream
1436  *
1437  * Return 0 on success or else a negative value.
1438  */
1439 static
1440 int viewer_get_packet(struct relay_connection *conn)
1441 {
1442         int ret, send_data = 0;
1443         char *data = NULL;
1444         uint32_t len = 0;
1445         ssize_t read_len;
1446         struct lttng_viewer_get_packet get_packet_info;
1447         struct lttng_viewer_trace_packet reply;
1448         struct relay_viewer_stream *stream;
1449         struct relay_session *session;
1450         struct ctf_trace *ctf_trace;
1451
1452         assert(conn);
1453
1454         DBG2("Relay get data packet");
1455
1456         health_code_update();
1457
1458         ret = recv_request(conn->sock, &get_packet_info, sizeof(get_packet_info));
1459         if (ret < 0) {
1460                 goto end;
1461         }
1462         health_code_update();
1463
1464         /* From this point on, the error label can be reached. */
1465         memset(&reply, 0, sizeof(reply));
1466
1467         rcu_read_lock();
1468         stream = viewer_stream_find_by_id(be64toh(get_packet_info.stream_id));
1469         if (!stream) {
1470                 goto error;
1471         }
1472
1473         session = session_find_by_id(conn->sessions_ht, stream->session_id);
1474         if (!session) {
1475                 ret = -1;
1476                 goto error;
1477         }
1478
1479         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
1480                         stream->path_name);
1481         assert(ctf_trace);
1482
1483         /*
1484          * First time we read this stream, we need open the tracefile, we should
1485          * only arrive here if an index has already been sent to the viewer, so the
1486          * tracefile must exist, if it does not it is a fatal error.
1487          */
1488         if (stream->read_fd < 0) {
1489                 char fullpath[PATH_MAX];
1490
1491                 if (stream->tracefile_count > 0) {
1492                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64, stream->path_name,
1493                                         stream->channel_name,
1494                                         stream->tracefile_count_current);
1495                 } else {
1496                         ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1497                                         stream->channel_name);
1498                 }
1499                 if (ret < 0) {
1500                         goto error;
1501                 }
1502                 ret = open(fullpath, O_RDONLY);
1503                 if (ret < 0) {
1504                         PERROR("Relay opening trace file");
1505                         goto error;
1506                 }
1507                 stream->read_fd = ret;
1508         }
1509
1510         if (!ctf_trace->metadata_received ||
1511                         ctf_trace->metadata_received > ctf_trace->metadata_sent) {
1512                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1513                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1514                 goto send_reply;
1515         }
1516
1517         ret = check_new_streams(conn);
1518         if (ret < 0) {
1519                 goto end_unlock;
1520         } else if (ret == 1) {
1521                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1522                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1523                 goto send_reply;
1524         }
1525
1526         len = be32toh(get_packet_info.len);
1527         data = zmalloc(len);
1528         if (!data) {
1529                 PERROR("relay data zmalloc");
1530                 goto error;
1531         }
1532
1533         ret = lseek(stream->read_fd, be64toh(get_packet_info.offset), SEEK_SET);
1534         if (ret < 0) {
1535                 /*
1536                  * If the read fd was closed by the streaming side, the
1537                  * abort_flag will be set to 1, otherwise it is an error.
1538                  */
1539                 if (stream->abort_flag == 0) {
1540                         PERROR("lseek");
1541                         goto error;
1542                 }
1543                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_EOF);
1544                 goto send_reply;
1545         }
1546         read_len = lttng_read(stream->read_fd, data, len);
1547         if (read_len < len) {
1548                 /*
1549                  * If the read fd was closed by the streaming side, the
1550                  * abort_flag will be set to 1, otherwise it is an error.
1551                  */
1552                 if (stream->abort_flag == 0) {
1553                         PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1554                                         stream->read_fd,
1555                                         be64toh(get_packet_info.offset));
1556                         goto error;
1557                 } else {
1558                         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_EOF);
1559                         goto send_reply;
1560                 }
1561         }
1562         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_OK);
1563         reply.len = htobe32(len);
1564         send_data = 1;
1565         goto send_reply;
1566
1567 error:
1568         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1569
1570 send_reply:
1571         reply.flags = htobe32(reply.flags);
1572
1573         health_code_update();
1574
1575         ret = send_response(conn->sock, &reply, sizeof(reply));
1576         if (ret < 0) {
1577                 goto end_unlock;
1578         }
1579         health_code_update();
1580
1581         if (send_data) {
1582                 health_code_update();
1583                 ret = send_response(conn->sock, data, len);
1584                 if (ret < 0) {
1585                         goto end_unlock;
1586                 }
1587                 health_code_update();
1588         }
1589
1590         DBG("Sent %u bytes for stream %" PRIu64, len,
1591                         be64toh(get_packet_info.stream_id));
1592
1593 end_unlock:
1594         free(data);
1595         rcu_read_unlock();
1596
1597 end:
1598         return ret;
1599 }
1600
1601 /*
1602  * Send the session's metadata
1603  *
1604  * Return 0 on success else a negative value.
1605  */
1606 static
1607 int viewer_get_metadata(struct relay_connection *conn)
1608 {
1609         int ret = 0;
1610         ssize_t read_len;
1611         uint64_t len = 0;
1612         char *data = NULL;
1613         struct lttng_viewer_get_metadata request;
1614         struct lttng_viewer_metadata_packet reply;
1615         struct relay_viewer_stream *stream;
1616         struct ctf_trace *ctf_trace;
1617         struct relay_session *session;
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         rcu_read_lock();
1634         stream = viewer_stream_find_by_id(be64toh(request.stream_id));
1635         if (!stream || !stream->metadata_flag) {
1636                 ERR("Invalid metadata stream");
1637                 goto error;
1638         }
1639
1640         session = session_find_by_id(conn->sessions_ht, stream->session_id);
1641         if (!session) {
1642                 ret = -1;
1643                 goto error;
1644         }
1645
1646         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
1647                         stream->path_name);
1648         assert(ctf_trace);
1649         assert(ctf_trace->metadata_sent <= ctf_trace->metadata_received);
1650
1651         len = ctf_trace->metadata_received - ctf_trace->metadata_sent;
1652         if (len == 0) {
1653                 reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
1654                 goto send_reply;
1655         }
1656
1657         /* first time, we open the metadata file */
1658         if (stream->read_fd < 0) {
1659                 char fullpath[PATH_MAX];
1660
1661                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1662                                 stream->channel_name);
1663                 if (ret < 0) {
1664                         goto error;
1665                 }
1666                 ret = open(fullpath, O_RDONLY);
1667                 if (ret < 0) {
1668                         PERROR("Relay opening metadata file");
1669                         goto error;
1670                 }
1671                 stream->read_fd = ret;
1672         }
1673
1674         reply.len = htobe64(len);
1675         data = zmalloc(len);
1676         if (!data) {
1677                 PERROR("viewer metadata zmalloc");
1678                 goto error;
1679         }
1680
1681         read_len = lttng_read(stream->read_fd, data, len);
1682         if (read_len < len) {
1683                 PERROR("Relay reading metadata file");
1684                 goto error;
1685         }
1686         ctf_trace->metadata_sent += read_len;
1687         reply.status = htobe32(LTTNG_VIEWER_METADATA_OK);
1688         goto send_reply;
1689
1690 error:
1691         reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1692
1693 send_reply:
1694         health_code_update();
1695         ret = send_response(conn->sock, &reply, sizeof(reply));
1696         if (ret < 0) {
1697                 goto end_unlock;
1698         }
1699         health_code_update();
1700
1701         if (len > 0) {
1702                 ret = send_response(conn->sock, data, len);
1703                 if (ret < 0) {
1704                         goto end_unlock;
1705                 }
1706         }
1707
1708         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1709                         be64toh(request.stream_id));
1710
1711         DBG("Metadata sent");
1712
1713 end_unlock:
1714         free(data);
1715         rcu_read_unlock();
1716 end:
1717         return ret;
1718 }
1719
1720 /*
1721  * Create a viewer session.
1722  *
1723  * Return 0 on success or else a negative value.
1724  */
1725 static
1726 int viewer_create_session(struct relay_connection *conn)
1727 {
1728         int ret;
1729         struct lttng_viewer_create_session_response resp;
1730
1731         DBG("Viewer create session received");
1732
1733         memset(&resp, 0, sizeof(resp));
1734         resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_OK);
1735         conn->viewer_session = zmalloc(sizeof(*conn->viewer_session));
1736         if (!conn->viewer_session) {
1737                 ERR("Allocation viewer session");
1738                 resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_ERR);
1739                 goto send_reply;
1740         }
1741         CDS_INIT_LIST_HEAD(&conn->viewer_session->sessions_head);
1742
1743 send_reply:
1744         health_code_update();
1745         ret = send_response(conn->sock, &resp, sizeof(resp));
1746         if (ret < 0) {
1747                 goto end;
1748         }
1749         health_code_update();
1750         ret = 0;
1751
1752 end:
1753         return ret;
1754 }
1755
1756
1757 /*
1758  * live_relay_unknown_command: send -1 if received unknown command
1759  */
1760 static
1761 void live_relay_unknown_command(struct relay_connection *conn)
1762 {
1763         struct lttcomm_relayd_generic_reply reply;
1764
1765         memset(&reply, 0, sizeof(reply));
1766         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1767         (void) send_response(conn->sock, &reply, sizeof(reply));
1768 }
1769
1770 /*
1771  * Process the commands received on the control socket
1772  */
1773 static
1774 int process_control(struct lttng_viewer_cmd *recv_hdr,
1775                 struct relay_connection *conn)
1776 {
1777         int ret = 0;
1778         uint32_t msg_value;
1779
1780         assert(recv_hdr);
1781         assert(conn);
1782
1783         msg_value = be32toh(recv_hdr->cmd);
1784
1785         /*
1786          * Make sure we've done the version check before any command other then a
1787          * new client connection.
1788          */
1789         if (msg_value != LTTNG_VIEWER_CONNECT && !conn->version_check_done) {
1790                 ERR("Viewer conn value %" PRIu32 " before version check", msg_value);
1791                 ret = -1;
1792                 goto end;
1793         }
1794
1795         switch (msg_value) {
1796         case LTTNG_VIEWER_CONNECT:
1797                 ret = viewer_connect(conn);
1798                 break;
1799         case LTTNG_VIEWER_LIST_SESSIONS:
1800                 ret = viewer_list_sessions(conn);
1801                 break;
1802         case LTTNG_VIEWER_ATTACH_SESSION:
1803                 ret = viewer_attach_session(conn);
1804                 break;
1805         case LTTNG_VIEWER_GET_NEXT_INDEX:
1806                 ret = viewer_get_next_index(conn);
1807                 break;
1808         case LTTNG_VIEWER_GET_PACKET:
1809                 ret = viewer_get_packet(conn);
1810                 break;
1811         case LTTNG_VIEWER_GET_METADATA:
1812                 ret = viewer_get_metadata(conn);
1813                 break;
1814         case LTTNG_VIEWER_GET_NEW_STREAMS:
1815                 ret = viewer_get_new_streams(conn);
1816                 break;
1817         case LTTNG_VIEWER_CREATE_SESSION:
1818                 ret = viewer_create_session(conn);
1819                 break;
1820         default:
1821                 ERR("Received unknown viewer command (%u)", be32toh(recv_hdr->cmd));
1822                 live_relay_unknown_command(conn);
1823                 ret = -1;
1824                 goto end;
1825         }
1826
1827 end:
1828         return ret;
1829 }
1830
1831 static
1832 void cleanup_connection_pollfd(struct lttng_poll_event *events, int pollfd)
1833 {
1834         int ret;
1835
1836         assert(events);
1837
1838         (void) lttng_poll_del(events, pollfd);
1839
1840         ret = close(pollfd);
1841         if (ret < 0) {
1842                 ERR("Closing pollfd %d", pollfd);
1843         }
1844 }
1845
1846 /*
1847  * Delete and destroy a connection.
1848  *
1849  * RCU read side lock MUST be acquired.
1850  */
1851 static void destroy_connection(struct lttng_ht *relay_connections_ht,
1852                 struct relay_connection *conn)
1853 {
1854         struct relay_session *session, *tmp_session;
1855
1856         assert(relay_connections_ht);
1857         assert(conn);
1858
1859         connection_delete(relay_connections_ht, conn);
1860
1861         if (!conn->viewer_session) {
1862                 goto end;
1863         }
1864
1865         rcu_read_lock();
1866         cds_list_for_each_entry_safe(session, tmp_session,
1867                         &conn->viewer_session->sessions_head,
1868                         viewer_session_list) {
1869                 DBG("Cleaning connection of session ID %" PRIu64, session->id);
1870                 cleanup_session(conn, session);
1871         }
1872         rcu_read_unlock();
1873
1874 end:
1875         connection_destroy(conn);
1876 }
1877
1878 /*
1879  * This thread does the actual work
1880  */
1881 static
1882 void *thread_worker(void *data)
1883 {
1884         int ret, err = -1;
1885         uint32_t nb_fd;
1886         struct relay_connection *conn;
1887         struct lttng_poll_event events;
1888         struct lttng_ht *relay_connections_ht;
1889         struct lttng_ht_iter iter;
1890         struct lttng_viewer_cmd recv_hdr;
1891         struct relay_local_data *relay_ctx = (struct relay_local_data *) data;
1892         struct lttng_ht *sessions_ht = relay_ctx->sessions_ht;
1893
1894         DBG("[thread] Live viewer relay worker started");
1895
1896         rcu_register_thread();
1897
1898         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1899
1900         if (testpoint(relayd_thread_live_worker)) {
1901                 goto error_testpoint;
1902         }
1903
1904         /* table of connections indexed on socket */
1905         relay_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1906         if (!relay_connections_ht) {
1907                 goto relay_connections_ht_error;
1908         }
1909
1910         ret = create_thread_poll_set(&events, 2);
1911         if (ret < 0) {
1912                 goto error_poll_create;
1913         }
1914
1915         ret = lttng_poll_add(&events, live_conn_pipe[0], LPOLLIN | LPOLLRDHUP);
1916         if (ret < 0) {
1917                 goto error;
1918         }
1919
1920 restart:
1921         while (1) {
1922                 int i;
1923
1924                 health_code_update();
1925
1926                 /* Infinite blocking call, waiting for transmission */
1927                 DBG3("Relayd live viewer worker thread polling...");
1928                 health_poll_entry();
1929                 ret = lttng_poll_wait(&events, -1);
1930                 health_poll_exit();
1931                 if (ret < 0) {
1932                         /*
1933                          * Restart interrupted system call.
1934                          */
1935                         if (errno == EINTR) {
1936                                 goto restart;
1937                         }
1938                         goto error;
1939                 }
1940
1941                 nb_fd = ret;
1942
1943                 /*
1944                  * Process control. The control connection is prioritised so we don't
1945                  * starve it with high throughput tracing data on the data
1946                  * connection.
1947                  */
1948                 for (i = 0; i < nb_fd; i++) {
1949                         /* Fetch once the poll data */
1950                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1951                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1952
1953                         health_code_update();
1954
1955                         /* Thread quit pipe has been closed. Killing thread. */
1956                         ret = check_thread_quit_pipe(pollfd, revents);
1957                         if (ret) {
1958                                 err = 0;
1959                                 goto exit;
1960                         }
1961
1962                         /* Inspect the relay conn pipe for new connection */
1963                         if (pollfd == live_conn_pipe[0]) {
1964                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1965                                         ERR("Relay live pipe error");
1966                                         goto error;
1967                                 } else if (revents & LPOLLIN) {
1968                                         ret = lttng_read(live_conn_pipe[0], &conn, sizeof(conn));
1969                                         if (ret < 0) {
1970                                                 goto error;
1971                                         }
1972                                         conn->sessions_ht = sessions_ht;
1973                                         connection_init(conn);
1974                                         lttng_poll_add(&events, conn->sock->fd,
1975                                                         LPOLLIN | LPOLLRDHUP);
1976                                         rcu_read_lock();
1977                                         lttng_ht_add_unique_ulong(relay_connections_ht,
1978                                                         &conn->sock_n);
1979                                         rcu_read_unlock();
1980                                         DBG("Connection socket %d added", conn->sock->fd);
1981                                 }
1982                         } else {
1983                                 rcu_read_lock();
1984                                 conn = connection_find_by_sock(relay_connections_ht, pollfd);
1985                                 /* If not found, there is a synchronization issue. */
1986                                 assert(conn);
1987
1988                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1989                                         cleanup_connection_pollfd(&events, pollfd);
1990                                         destroy_connection(relay_connections_ht, conn);
1991                                 } else if (revents & LPOLLIN) {
1992                                         ret = conn->sock->ops->recvmsg(conn->sock, &recv_hdr,
1993                                                         sizeof(recv_hdr), 0);
1994                                         if (ret <= 0) {
1995                                                 /* Connection closed */
1996                                                 cleanup_connection_pollfd(&events, pollfd);
1997                                                 destroy_connection(relay_connections_ht, conn);
1998                                                 DBG("Viewer control conn closed with %d", pollfd);
1999                                         } else {
2000                                                 ret = process_control(&recv_hdr, conn);
2001                                                 if (ret < 0) {
2002                                                         /* Clear the session on error. */
2003                                                         cleanup_connection_pollfd(&events, pollfd);
2004                                                         destroy_connection(relay_connections_ht, conn);
2005                                                         DBG("Viewer connection closed with %d", pollfd);
2006                                                 }
2007                                         }
2008                                 }
2009                                 rcu_read_unlock();
2010                         }
2011                 }
2012         }
2013
2014 exit:
2015 error:
2016         lttng_poll_clean(&events);
2017
2018         /* Cleanup reamaining connection object. */
2019         rcu_read_lock();
2020         cds_lfht_for_each_entry(relay_connections_ht->ht, &iter.iter, conn,
2021                         sock_n.node) {
2022                 health_code_update();
2023                 destroy_connection(relay_connections_ht, conn);
2024         }
2025         rcu_read_unlock();
2026 error_poll_create:
2027         lttng_ht_destroy(relay_connections_ht);
2028 relay_connections_ht_error:
2029         /* Close relay conn pipes */
2030         utils_close_pipe(live_conn_pipe);
2031         if (err) {
2032                 DBG("Viewer worker thread exited with error");
2033         }
2034         DBG("Viewer worker thread cleanup complete");
2035 error_testpoint:
2036         if (err) {
2037                 health_error();
2038                 ERR("Health error occurred in %s", __func__);
2039         }
2040         health_unregister(health_relayd);
2041         if (stop_threads()) {
2042                 ERR("Error stopping live threads");
2043         }
2044         rcu_unregister_thread();
2045         return NULL;
2046 }
2047
2048 /*
2049  * Create the relay command pipe to wake thread_manage_apps.
2050  * Closed in cleanup().
2051  */
2052 static int create_conn_pipe(void)
2053 {
2054         return utils_create_pipe_cloexec(live_conn_pipe);
2055 }
2056
2057 int relayd_live_stop(void)
2058 {
2059         return stop_threads();
2060 }
2061
2062 int relayd_live_join(void)
2063 {
2064         int ret, retval = 0;
2065         void *status;
2066
2067         ret = pthread_join(live_listener_thread, &status);
2068         if (ret) {
2069                 errno = ret;
2070                 PERROR("pthread_join live listener");
2071                 retval = -1;
2072         }
2073
2074         ret = pthread_join(live_worker_thread, &status);
2075         if (ret) {
2076                 errno = ret;
2077                 PERROR("pthread_join live worker");
2078                 retval = -1;
2079         }
2080
2081         ret = pthread_join(live_dispatcher_thread, &status);
2082         if (ret) {
2083                 errno = ret;
2084                 PERROR("pthread_join live dispatcher");
2085                 retval = -1;
2086         }
2087
2088         cleanup_relayd_live();
2089
2090         return retval;
2091 }
2092
2093 /*
2094  * main
2095  */
2096 int relayd_live_create(struct lttng_uri *uri,
2097                 struct relay_local_data *relay_ctx)
2098 {
2099         int ret = 0, retval = 0;
2100         void *status;
2101         int is_root;
2102
2103         if (!uri) {
2104                 retval = -1;
2105                 goto exit_init_data;
2106         }
2107         live_uri = uri;
2108
2109         /* Check if daemon is UID = 0 */
2110         is_root = !getuid();
2111
2112         if (!is_root) {
2113                 if (live_uri->port < 1024) {
2114                         ERR("Need to be root to use ports < 1024");
2115                         retval = -1;
2116                         goto exit_init_data;
2117                 }
2118         }
2119
2120         /* Setup the thread apps communication pipe. */
2121         if (create_conn_pipe()) {
2122                 retval = -1;
2123                 goto exit_init_data;
2124         }
2125
2126         /* Init relay command queue. */
2127         cds_wfcq_init(&viewer_conn_queue.head, &viewer_conn_queue.tail);
2128
2129         /* Set up max poll set size */
2130         lttng_poll_set_max_size();
2131
2132         /* Setup the dispatcher thread */
2133         ret = pthread_create(&live_dispatcher_thread, NULL,
2134                         thread_dispatcher, (void *) NULL);
2135         if (ret) {
2136                 errno = ret;
2137                 PERROR("pthread_create viewer dispatcher");
2138                 retval = -1;
2139                 goto exit_dispatcher_thread;
2140         }
2141
2142         /* Setup the worker thread */
2143         ret = pthread_create(&live_worker_thread, NULL,
2144                         thread_worker, relay_ctx);
2145         if (ret) {
2146                 errno = ret;
2147                 PERROR("pthread_create viewer worker");
2148                 retval = -1;
2149                 goto exit_worker_thread;
2150         }
2151
2152         /* Setup the listener thread */
2153         ret = pthread_create(&live_listener_thread, NULL,
2154                         thread_listener, (void *) NULL);
2155         if (ret) {
2156                 errno = ret;
2157                 PERROR("pthread_create viewer listener");
2158                 retval = -1;
2159                 goto exit_listener_thread;
2160         }
2161
2162         /*
2163          * All OK, started all threads.
2164          */
2165         return retval;
2166
2167
2168         ret = pthread_join(live_listener_thread, &status);
2169         if (ret) {
2170                 errno = ret;
2171                 PERROR("pthread_join live listener");
2172                 retval = -1;
2173         }
2174 exit_listener_thread:
2175
2176         ret = pthread_join(live_worker_thread, &status);
2177         if (ret) {
2178                 errno = ret;
2179                 PERROR("pthread_join live worker");
2180                 retval = -1;
2181         }
2182 exit_worker_thread:
2183
2184         ret = pthread_join(live_dispatcher_thread, &status);
2185         if (ret) {
2186                 errno = ret;
2187                 PERROR("pthread_join live dispatcher");
2188                 retval = -1;
2189         }
2190 exit_dispatcher_thread:
2191
2192 exit_init_data:
2193         cleanup_relayd_live();
2194
2195         return retval;
2196 }