src/bin/lttng-relayd/live.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <getopt.h>
  21 #include <grp.h>
  22 #include <limits.h>
  23 #include <pthread.h>
  24 #include <signal.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sys/mman.h>
  29 #include <sys/mount.h>
  30 #include <sys/resource.h>
  31 #include <sys/socket.h>
  32 #include <sys/stat.h>
  33 #include <sys/types.h>
  34 #include <sys/wait.h>
  35 #include <inttypes.h>
  36 #include <urcu/futex.h>
  37 #include <urcu/uatomic.h>
  38 #include <unistd.h>
  39 #include <fcntl.h>
  40 #include <config.h>
  41
  42 #include <lttng/lttng.h>
  43 #include <common/common.h>
  44 #include <common/compat/poll.h>
  45 #include <common/compat/socket.h>
  46 #include <common/defaults.h>
  47 #include <common/futex.h>
  48 #include <common/sessiond-comm/sessiond-comm.h>
  49 #include <common/sessiond-comm/inet.h>
  50 #include <common/sessiond-comm/relayd.h>
  51 #include <common/uri.h>
  52 #include <common/utils.h>
  53
  54 #include "cmd.h"
  55 #include "live.h"
  56 #include "lttng-relayd.h"
  57 #include "lttng-viewer.h"
  58 #include "utils.h"
  59 #include "health-relayd.h"
  60
  61 static struct lttng_uri *live_uri;
  62
  63 /*
  64  * Quit pipe for all threads. This permits a single cancellation point
  65  * for all threads when receiving an event on the pipe.
  66  */
  67 static int live_thread_quit_pipe[2] = { -1, -1 };
  68
  69 /*
  70  * This pipe is used to inform the worker thread that a command is queued and
  71  * ready to be processed.
  72  */
  73 static int live_relay_cmd_pipe[2] = { -1, -1 };
  74
  75 /* Shared between threads */
  76 static int live_dispatch_thread_exit;
  77
  78 static pthread_t live_listener_thread;
  79 static pthread_t live_dispatcher_thread;
  80 static pthread_t live_worker_thread;
  81
  82 /*
  83  * Relay command queue.
  84  *
  85  * The live_thread_listener and live_thread_dispatcher communicate with this
  86  * queue.
  87  */
  88 static struct relay_cmd_queue viewer_cmd_queue;
  89
  90 static uint64_t last_relay_viewer_session_id;
  91
  92 /*
  93  * Cleanup the daemon
  94  */
  95 static
  96 void cleanup(void)
  97 {
  98         DBG("Cleaning up");
  99
 100         free(live_uri);
 101 }
 102
 103 /*
 104  * Write to writable pipe used to notify a thread.
 105  */
 106 static
 107 int notify_thread_pipe(int wpipe)
 108 {
 109         ssize_t ret;
 110
 111         ret = lttng_write(wpipe, "!", 1);
 112         if (ret < 1) {
 113                 PERROR("write poll pipe");
 114         }
 115
 116         return (int) ret;
 117 }
 118
 119 /*
 120  * Stop all threads by closing the thread quit pipe.
 121  */
 122 static
 123 void stop_threads(void)
 124 {
 125         int ret;
 126
 127         /* Stopping all threads */
 128         DBG("Terminating all live threads");
 129         ret = notify_thread_pipe(live_thread_quit_pipe[1]);
 130         if (ret < 0) {
 131                 ERR("write error on thread quit pipe");
 132         }
 133
 134         /* Dispatch thread */
 135         CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
 136         futex_nto1_wake(&viewer_cmd_queue.futex);
 137 }
 138
 139 /*
 140  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 141  */
 142 static
 143 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 144 {
 145         int ret;
 146
 147         if (events == NULL || size == 0) {
 148                 ret = -1;
 149                 goto error;
 150         }
 151
 152         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 153         if (ret < 0) {
 154                 goto error;
 155         }
 156
 157         /* Add quit pipe */
 158         ret = lttng_poll_add(events, live_thread_quit_pipe[0], LPOLLIN);
 159         if (ret < 0) {
 160                 goto error;
 161         }
 162
 163         return 0;
 164
 165 error:
 166         return ret;
 167 }
 168
 169 /*
 170  * Check if the thread quit pipe was triggered.
 171  *
 172  * Return 1 if it was triggered else 0;
 173  */
 174 static
 175 int check_thread_quit_pipe(int fd, uint32_t events)
 176 {
 177         if (fd == live_thread_quit_pipe[0] && (events & LPOLLIN)) {
 178                 return 1;
 179         }
 180
 181         return 0;
 182 }
 183
 184 /*
 185  * Create and init socket from uri.
 186  */
 187 static
 188 struct lttcomm_sock *init_socket(struct lttng_uri *uri)
 189 {
 190         int ret;
 191         struct lttcomm_sock *sock = NULL;
 192
 193         sock = lttcomm_alloc_sock_from_uri(uri);
 194         if (sock == NULL) {
 195                 ERR("Allocating socket");
 196                 goto error;
 197         }
 198
 199         ret = lttcomm_create_sock(sock);
 200         if (ret < 0) {
 201                 goto error;
 202         }
 203         DBG("Listening on sock %d for live", sock->fd);
 204
 205         ret = sock->ops->bind(sock);
 206         if (ret < 0) {
 207                 goto error;
 208         }
 209
 210         ret = sock->ops->listen(sock, -1);
 211         if (ret < 0) {
 212                 goto error;
 213
 214         }
 215
 216         return sock;
 217
 218 error:
 219         if (sock) {
 220                 lttcomm_destroy_sock(sock);
 221         }
 222         return NULL;
 223 }
 224
 225 /*
 226  * This thread manages the listening for new connections on the network
 227  */
 228 static
 229 void *thread_listener(void *data)
 230 {
 231         int i, ret, pollfd, err = -1;
 232         int val = 1;
 233         uint32_t revents, nb_fd;
 234         struct lttng_poll_event events;
 235         struct lttcomm_sock *live_control_sock;
 236
 237         DBG("[thread] Relay live listener started");
 238
 239         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_LISTENER);
 240
 241         health_code_update();
 242
 243         live_control_sock = init_socket(live_uri);
 244         if (!live_control_sock) {
 245                 goto error_sock_control;
 246         }
 247
 248         /*
 249          * Pass 3 as size here for the thread quit pipe, control and data socket.
 250          */
 251         ret = create_thread_poll_set(&events, 2);
 252         if (ret < 0) {
 253                 goto error_create_poll;
 254         }
 255
 256         /* Add the control socket */
 257         ret = lttng_poll_add(&events, live_control_sock->fd, LPOLLIN | LPOLLRDHUP);
 258         if (ret < 0) {
 259                 goto error_poll_add;
 260         }
 261
 262         while (1) {
 263                 health_code_update();
 264
 265                 DBG("Listener accepting live viewers connections");
 266
 267 restart:
 268                 health_poll_entry();
 269                 ret = lttng_poll_wait(&events, -1);
 270                 health_poll_exit();
 271                 if (ret < 0) {
 272                         /*
 273                          * Restart interrupted system call.
 274                          */
 275                         if (errno == EINTR) {
 276                                 goto restart;
 277                         }
 278                         goto error;
 279                 }
 280                 nb_fd = ret;
 281
 282                 DBG("Relay new viewer connection received");
 283                 for (i = 0; i < nb_fd; i++) {
 284                         health_code_update();
 285
 286                         /* Fetch once the poll data */
 287                         revents = LTTNG_POLL_GETEV(&events, i);
 288                         pollfd = LTTNG_POLL_GETFD(&events, i);
 289
 290                         /* Thread quit pipe has been closed. Killing thread. */
 291                         ret = check_thread_quit_pipe(pollfd, revents);
 292                         if (ret) {
 293                                 err = 0;
 294                                 goto exit;
 295                         }
 296
 297                         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 298                                 ERR("socket poll error");
 299                                 goto error;
 300                         } else if (revents & LPOLLIN) {
 301                                 /*
 302                                  * Get allocated in this thread, enqueued to a global queue,
 303                                  * dequeued and freed in the worker thread.
 304                                  */
 305                                 struct relay_command *relay_cmd;
 306                                 struct lttcomm_sock *newsock;
 307
 308                                 relay_cmd = zmalloc(sizeof(*relay_cmd));
 309                                 if (!relay_cmd) {
 310                                         PERROR("relay command zmalloc");
 311                                         goto error;
 312                                 }
 313
 314                                 assert(pollfd == live_control_sock->fd);
 315                                 newsock = live_control_sock->ops->accept(live_control_sock);
 316                                 if (!newsock) {
 317                                         PERROR("accepting control sock");
 318                                         free(relay_cmd);
 319                                         goto error;
 320                                 }
 321                                 DBG("Relay viewer connection accepted socket %d", newsock->fd);
 322                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR, &val,
 323                                                 sizeof(int));
 324                                 if (ret < 0) {
 325                                         PERROR("setsockopt inet");
 326                                         lttcomm_destroy_sock(newsock);
 327                                         free(relay_cmd);
 328                                         goto error;
 329                                 }
 330                                 relay_cmd->sock = newsock;
 331
 332                                 /*
 333                                  * Lock free enqueue the request.
 334                                  */
 335                                 cds_wfq_enqueue(&viewer_cmd_queue.queue, &relay_cmd->node);
 336
 337                                 /*
 338                                  * Wake the dispatch queue futex. Implicit memory
 339                                  * barrier with the exchange in cds_wfq_enqueue.
 340                                  */
 341                                 futex_nto1_wake(&viewer_cmd_queue.futex);
 342                         }
 343                 }
 344         }
 345
 346 exit:
 347 error:
 348 error_poll_add:
 349         lttng_poll_clean(&events);
 350 error_create_poll:
 351         if (live_control_sock->fd >= 0) {
 352                 ret = live_control_sock->ops->close(live_control_sock);
 353                 if (ret) {
 354                         PERROR("close");
 355                 }
 356         }
 357         lttcomm_destroy_sock(live_control_sock);
 358 error_sock_control:
 359         if (err) {
 360                 health_error();
 361                 DBG("Live viewer listener thread exited with error");
 362         }
 363         health_unregister(health_relayd);
 364         DBG("Live viewer listener thread cleanup complete");
 365         stop_threads();
 366         return NULL;
 367 }
 368
 369 /*
 370  * This thread manages the dispatching of the requests to worker threads
 371  */
 372 static
 373 void *thread_dispatcher(void *data)
 374 {
 375         int err = -1;
 376         ssize_t ret;
 377         struct cds_wfq_node *node;
 378         struct relay_command *relay_cmd = NULL;
 379
 380         DBG("[thread] Live viewer relay dispatcher started");
 381
 382         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 383
 384         health_code_update();
 385
 386         while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 387                 health_code_update();
 388
 389                 /* Atomically prepare the queue futex */
 390                 futex_nto1_prepare(&viewer_cmd_queue.futex);
 391
 392                 do {
 393                         health_code_update();
 394
 395                         /* Dequeue commands */
 396                         node = cds_wfq_dequeue_blocking(&viewer_cmd_queue.queue);
 397                         if (node == NULL) {
 398                                 DBG("Woken up but nothing in the live-viewer "
 399                                                 "relay command queue");
 400                                 /* Continue thread execution */
 401                                 break;
 402                         }
 403
 404                         relay_cmd = caa_container_of(node, struct relay_command, node);
 405                         DBG("Dispatching viewer request waiting on sock %d",
 406                                         relay_cmd->sock->fd);
 407
 408                         /*
 409                          * Inform worker thread of the new request. This call is blocking
 410                          * so we can be assured that the data will be read at some point in
 411                          * time or wait to the end of the world :)
 412                          */
 413                         ret = lttng_write(live_relay_cmd_pipe[1], relay_cmd,
 414                                         sizeof(*relay_cmd));
 415                         free(relay_cmd);
 416                         if (ret < sizeof(struct relay_command)) {
 417                                 PERROR("write cmd pipe");
 418                                 goto error;
 419                         }
 420                 } while (node != NULL);
 421
 422                 /* Futex wait on queue. Blocking call on futex() */
 423                 health_poll_entry();
 424                 futex_nto1_wait(&viewer_cmd_queue.futex);
 425                 health_poll_exit();
 426         }
 427
 428         /* Normal exit, no error */
 429         err = 0;
 430
 431 error:
 432         if (err) {
 433                 health_error();
 434                 ERR("Health error occurred in %s", __func__);
 435         }
 436         health_unregister(health_relayd);
 437         DBG("Live viewer dispatch thread dying");
 438         stop_threads();
 439         return NULL;
 440 }
 441
 442 /*
 443  * Establish connection with the viewer and check the versions.
 444  *
 445  * Return 0 on success or else negative value.
 446  */
 447 static
 448 int viewer_connect(struct relay_command *cmd)
 449 {
 450         int ret;
 451         struct lttng_viewer_connect reply, msg;
 452
 453         assert(cmd);
 454
 455         cmd->version_check_done = 1;
 456
 457         health_code_update();
 458
 459         /* Get version from the other side. */
 460         ret = cmd->sock->ops->recvmsg(cmd->sock, &msg, sizeof(msg), 0);
 461         if (ret < 0 || ret != sizeof(msg)) {
 462                 if (ret == 0) {
 463                         /* Orderly shutdown. Not necessary to print an error. */
 464                         DBG("Socket %d did an orderly shutdown", cmd->sock->fd);
 465                 } else {
 466                         ERR("Relay failed to receive the version values.");
 467                 }
 468                 ret = -1;
 469                 goto end;
 470         }
 471
 472         health_code_update();
 473
 474         reply.major = RELAYD_VERSION_COMM_MAJOR;
 475         reply.minor = RELAYD_VERSION_COMM_MINOR;
 476
 477         /* Major versions must be the same */
 478         if (reply.major != be32toh(msg.major)) {
 479                 DBG("Incompatible major versions (%u vs %u)", reply.major,
 480                                 be32toh(msg.major));
 481                 ret = 0;
 482                 goto end;
 483         }
 484
 485         cmd->major = reply.major;
 486         /* We adapt to the lowest compatible version */
 487         if (reply.minor <= be32toh(msg.minor)) {
 488                 cmd->minor = reply.minor;
 489         } else {
 490                 cmd->minor = be32toh(msg.minor);
 491         }
 492
 493         if (be32toh(msg.type) == VIEWER_CLIENT_COMMAND) {
 494                 cmd->type = RELAY_VIEWER_COMMAND;
 495         } else if (be32toh(msg.type) == VIEWER_CLIENT_NOTIFICATION) {
 496                 cmd->type = RELAY_VIEWER_NOTIFICATION;
 497         } else {
 498                 ERR("Unknown connection type : %u", be32toh(msg.type));
 499                 ret = -1;
 500                 goto end;
 501         }
 502
 503         reply.major = htobe32(reply.major);
 504         reply.minor = htobe32(reply.minor);
 505         if (cmd->type == RELAY_VIEWER_COMMAND) {
 506                 reply.viewer_session_id = htobe64(++last_relay_viewer_session_id);
 507         }
 508
 509         health_code_update();
 510
 511         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
 512                         sizeof(struct lttng_viewer_connect), 0);
 513         if (ret < 0) {
 514                 ERR("Relay sending version");
 515         }
 516
 517         health_code_update();
 518
 519         DBG("Version check done using protocol %u.%u", cmd->major, cmd->minor);
 520         ret = 0;
 521
 522 end:
 523         return ret;
 524 }
 525
 526 /*
 527  * Send the viewer the list of current sessions.
 528  *
 529  * Return 0 on success or else a negative value.
 530  */
 531 static
 532 int viewer_list_sessions(struct relay_command *cmd,
 533                 struct lttng_ht *sessions_ht)
 534 {
 535         int ret;
 536         struct lttng_viewer_list_sessions session_list;
 537         unsigned long count;
 538         long approx_before, approx_after;
 539         struct lttng_ht_node_ulong *node;
 540         struct lttng_ht_iter iter;
 541         struct lttng_viewer_session send_session;
 542         struct relay_session *session;
 543
 544         DBG("List sessions received");
 545
 546         if (cmd->version_check_done == 0) {
 547                 ERR("Trying to list sessions before version check");
 548                 ret = -1;
 549                 goto end_no_session;
 550         }
 551
 552         rcu_read_lock();
 553         cds_lfht_count_nodes(sessions_ht->ht, &approx_before, &count, &approx_after);
 554         session_list.sessions_count = htobe32(count);
 555
 556         health_code_update();
 557
 558         ret = cmd->sock->ops->sendmsg(cmd->sock, &session_list,
 559                         sizeof(session_list), 0);
 560         if (ret < 0) {
 561                 ERR("Relay sending sessions list");
 562                 goto end_unlock;
 563         }
 564
 565         health_code_update();
 566
 567         cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, node, node) {
 568                 health_code_update();
 569
 570                 node = lttng_ht_iter_get_node_ulong(&iter);
 571                 if (!node) {
 572                         goto end_unlock;
 573                 }
 574                 session = caa_container_of(node, struct relay_session, session_n);
 575
 576                 strncpy(send_session.session_name, session->session_name,
 577                                 sizeof(send_session.session_name));
 578                 strncpy(send_session.hostname, session->hostname,
 579                                 sizeof(send_session.hostname));
 580                 send_session.id = htobe64(session->id);
 581                 send_session.live_timer = htobe32(session->live_timer);
 582                 send_session.clients = htobe32(session->viewer_attached);
 583                 send_session.streams = htobe32(session->stream_count);
 584
 585                 health_code_update();
 586
 587                 ret = cmd->sock->ops->sendmsg(cmd->sock, &send_session,
 588                                 sizeof(send_session), 0);
 589                 if (ret < 0) {
 590                         ERR("Relay sending session info");
 591                         goto end_unlock;
 592                 }
 593         }
 594         health_code_update();
 595
 596         rcu_read_unlock();
 597         ret = 0;
 598         goto end;
 599
 600 end_unlock:
 601         rcu_read_unlock();
 602
 603 end:
 604 end_no_session:
 605         return ret;
 606 }
 607
 608 /*
 609  * Open index file using a given viewer stream.
 610  *
 611  * Return 0 on success or else a negative value.
 612  */
 613 static int open_index(struct relay_viewer_stream *stream)
 614 {
 615         int ret;
 616         char fullpath[PATH_MAX];
 617         struct lttng_packet_index_file_hdr hdr;
 618
 619         if (stream->tracefile_count > 0) {
 620                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 621                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, stream->path_name,
 622                                 stream->channel_name, stream->tracefile_count_current);
 623         } else {
 624                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 625                                 DEFAULT_INDEX_FILE_SUFFIX, stream->path_name,
 626                                 stream->channel_name);
 627         }
 628         if (ret < 0) {
 629                 PERROR("snprintf index path");
 630                 goto error;
 631         }
 632
 633         DBG("Opening index file %s in read only", fullpath);
 634         ret = open(fullpath, O_RDONLY);
 635         if (ret < 0) {
 636                 if (errno == ENOENT) {
 637                         ret = -ENOENT;
 638                         goto error;
 639                 } else {
 640                         PERROR("opening index in read-only");
 641                 }
 642                 goto error;
 643         }
 644         stream->index_read_fd = ret;
 645         DBG("Opening index file %s in read only, (fd: %d)", fullpath, ret);
 646
 647         ret = lttng_read(stream->index_read_fd, &hdr, sizeof(hdr));
 648         if (ret < sizeof(hdr)) {
 649                 PERROR("Reading index header");
 650                 goto error;
 651         }
 652         if (strncmp(hdr.magic, INDEX_MAGIC, sizeof(hdr.magic)) != 0) {
 653                 ERR("Invalid header magic");
 654                 ret = -1;
 655                 goto error;
 656         }
 657         if (be32toh(hdr.index_major) != INDEX_MAJOR ||
 658                         be32toh(hdr.index_minor) != INDEX_MINOR) {
 659                 ERR("Invalid header version");
 660                 ret = -1;
 661                 goto error;
 662         }
 663         ret = 0;
 664
 665 error:
 666         return ret;
 667 }
 668
 669 /*
 670  * Allocate and init a new viewer_stream.
 671  *
 672  * Copies the values from the stream passed in parameter and insert the new
 673  * stream in the viewer_streams_ht.
 674  *
 675  * MUST be called with rcu_read_lock held.
 676  *
 677  * Returns 0 on success or a negative value on error.
 678  */
 679 static
 680 int init_viewer_stream(struct relay_stream *stream, int seek_last)
 681 {
 682         int ret;
 683         struct relay_viewer_stream *viewer_stream;
 684
 685         assert(stream);
 686
 687         viewer_stream = zmalloc(sizeof(*viewer_stream));
 688         if (!viewer_stream) {
 689                 PERROR("relay viewer stream zmalloc");
 690                 ret = -1;
 691                 goto error;
 692         }
 693         viewer_stream->session_id = stream->session->id;
 694         viewer_stream->stream_handle = stream->stream_handle;
 695         viewer_stream->path_name = strndup(stream->path_name,
 696                         LTTNG_VIEWER_PATH_MAX);
 697         viewer_stream->channel_name = strndup(stream->channel_name,
 698                         LTTNG_VIEWER_NAME_MAX);
 699         viewer_stream->tracefile_count = stream->tracefile_count;
 700         viewer_stream->metadata_flag = stream->metadata_flag;
 701         if (seek_last) {
 702                 viewer_stream->tracefile_count_current =
 703                         stream->tracefile_count_current;
 704         } else {
 705                 viewer_stream->tracefile_count_current =
 706                         stream->oldest_tracefile_id;
 707         }
 708
 709         /*
 710          * The deletion of this ctf_trace object is only done in a call RCU of the
 711          * relay stream making it valid as long as we have the read side lock.
 712          */
 713         viewer_stream->ctf_trace = stream->ctf_trace;
 714         uatomic_inc(&viewer_stream->ctf_trace->refcount);
 715
 716         lttng_ht_node_init_u64(&viewer_stream->stream_n, stream->stream_handle);
 717         lttng_ht_add_unique_u64(viewer_streams_ht, &viewer_stream->stream_n);
 718
 719         viewer_stream->index_read_fd = -1;
 720         viewer_stream->read_fd = -1;
 721
 722         /*
 723          * This is to avoid a race between the initialization of this object and
 724          * the close of the given stream. If the stream is unable to find this
 725          * viewer stream when closing, this copy will at least take the latest
 726          * value.
 727          * We also need that for the seek_last.
 728          */
 729         viewer_stream->total_index_received = stream->total_index_received;
 730
 731         /*
 732          * If we never received an index for the current stream, delay
 733          * the opening of the index, otherwise open it right now.
 734          */
 735         if (viewer_stream->tracefile_count_current ==
 736                         stream->tracefile_count_current &&
 737                         viewer_stream->total_index_received == 0) {
 738                 viewer_stream->index_read_fd = -1;
 739         } else {
 740                 ret = open_index(viewer_stream);
 741                 if (ret < 0) {
 742                         goto error;
 743                 }
 744         }
 745
 746         if (seek_last && viewer_stream->index_read_fd > 0) {
 747                 ret = lseek(viewer_stream->index_read_fd,
 748                                 viewer_stream->total_index_received *
 749                                         sizeof(struct lttng_packet_index),
 750                                 SEEK_CUR);
 751                 if (ret < 0) {
 752                         goto error;
 753                 }
 754                 viewer_stream->last_sent_index =
 755                         viewer_stream->total_index_received;
 756         }
 757
 758         ret = 0;
 759
 760 error:
 761         return ret;
 762 }
 763
 764 /*
 765  * Rotate a stream to the next tracefile.
 766  *
 767  * Returns 0 on success, a negative value on error.
 768  */
 769 static
 770 int rotate_viewer_stream(struct relay_viewer_stream *viewer_stream,
 771                 struct relay_stream *stream)
 772 {
 773         int ret;
 774         uint64_t tracefile_id;
 775
 776         assert(viewer_stream);
 777
 778         tracefile_id = (viewer_stream->tracefile_count_current + 1) %
 779                 viewer_stream->tracefile_count;
 780
 781         if (stream) {
 782                 pthread_mutex_lock(&stream->viewer_stream_rotation_lock);
 783         }
 784         /*
 785          * The writer and the reader are not working in the same
 786          * tracefile, we can read up to EOF, we don't care about the
 787          * total_index_received.
 788          */
 789         if (!stream || (stream->tracefile_count_current != tracefile_id)) {
 790                 viewer_stream->close_write_flag = 1;
 791         } else {
 792                 /*
 793                  * We are opening a file that is still open in write, make
 794                  * sure we limit our reading to the number of indexes
 795                  * received.
 796                  */
 797                 viewer_stream->close_write_flag = 0;
 798                 if (stream) {
 799                         viewer_stream->total_index_received =
 800                                 stream->total_index_received;
 801                 }
 802         }
 803         viewer_stream->tracefile_count_current = tracefile_id;
 804         pthread_mutex_unlock(&stream->viewer_stream_rotation_lock);
 805
 806         if (viewer_stream->abort_flag == 0) {
 807                 ret = close(viewer_stream->index_read_fd);
 808                 if (ret < 0) {
 809                         PERROR("close index file");
 810                 }
 811                 ret = close(viewer_stream->read_fd);
 812                 if (ret < 0) {
 813                         PERROR("close tracefile");
 814                 }
 815         } else {
 816                 viewer_stream->abort_flag = 0;
 817         }
 818
 819         viewer_stream->read_fd = -1;
 820
 821         ret = open_index(viewer_stream);
 822         if (ret < 0) {
 823                 goto error;
 824         }
 825
 826         ret = 0;
 827
 828 error:
 829         return ret;
 830 }
 831
 832 /*
 833  * Send the viewer the list of current sessions.
 834  */
 835 static
 836 int viewer_attach_session(struct relay_command *cmd,
 837                 struct lttng_ht *sessions_ht)
 838 {
 839         int ret, send_streams = 0, nb_streams = 0;
 840         struct lttng_viewer_attach_session_request request;
 841         struct lttng_viewer_attach_session_response response;
 842         struct lttng_viewer_stream send_stream;
 843         struct relay_stream *stream;
 844         struct relay_viewer_stream *viewer_stream;
 845         struct lttng_ht_node_ulong *node;
 846         struct lttng_ht_node_u64 *node64;
 847         struct lttng_ht_iter iter;
 848         struct relay_session *session;
 849         int seek_last = 0;
 850
 851         assert(cmd);
 852         assert(sessions_ht);
 853
 854         DBG("Attach session received");
 855
 856         if (cmd->version_check_done == 0) {
 857                 ERR("Trying to attach session before version check");
 858                 ret = -1;
 859                 goto end_no_session;
 860         }
 861
 862         health_code_update();
 863
 864         ret = cmd->sock->ops->recvmsg(cmd->sock, &request, sizeof(request), 0);
 865         if (ret < 0 || ret != sizeof(request)) {
 866                 if (ret == 0) {
 867                         /* Orderly shutdown. Not necessary to print an error. */
 868                         DBG("Socket %d did an orderly shutdown", cmd->sock->fd);
 869                 } else {
 870                         ERR("Relay failed to receive the attach parameters.");
 871                 }
 872                 ret = -1;
 873                 goto error;
 874         }
 875
 876         health_code_update();
 877
 878         rcu_read_lock();
 879         lttng_ht_lookup(sessions_ht,
 880                         (void *)((unsigned long) be64toh(request.session_id)), &iter);
 881         node = lttng_ht_iter_get_node_ulong(&iter);
 882         if (node == NULL) {
 883                 DBG("Relay session %" PRIu64 " not found",
 884                                 be64toh(request.session_id));
 885                 response.status = htobe32(VIEWER_ATTACH_UNK);
 886                 goto send_reply;
 887         }
 888
 889         session = caa_container_of(node, struct relay_session, session_n);
 890         if (cmd->session_id == session->id) {
 891                 /* Same viewer already attached, just send the stream list. */
 892                 send_streams = 1;
 893                 response.status = htobe32(VIEWER_ATTACH_OK);
 894         } else if (session->viewer_attached != 0) {
 895                 DBG("Already a viewer attached");
 896                 response.status = htobe32(VIEWER_ATTACH_ALREADY);
 897                 goto send_reply;
 898         } else if (session->live_timer == 0) {
 899                 DBG("Not live session");
 900                 response.status = htobe32(VIEWER_ATTACH_NOT_LIVE);
 901                 goto send_reply;
 902         } else {
 903                 session->viewer_attached++;
 904                 send_streams = 1;
 905                 response.status = htobe32(VIEWER_ATTACH_OK);
 906                 cmd->session_id = session->id;
 907                 cmd->session = session;
 908         }
 909
 910         switch (be32toh(request.seek)) {
 911         case VIEWER_SEEK_BEGINNING:
 912                 /* Default behaviour. */
 913                 break;
 914         case VIEWER_SEEK_LAST:
 915                 seek_last = 1;
 916                 break;
 917         default:
 918                 ERR("Wrong seek parameter");
 919                 response.status = htobe32(VIEWER_ATTACH_SEEK_ERR);
 920                 send_streams = 0;
 921                 goto send_reply;
 922         }
 923
 924         if (send_streams) {
 925                 /* We should only be there if we have a session to attach to. */
 926                 assert(session);
 927
 928                 /*
 929                  * Fill the viewer_streams_ht to count the number of streams
 930                  * ready to be sent and avoid concurrency issues on the
 931                  * relay_streams_ht and don't rely on a total session stream count.
 932                  */
 933                 cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, node, node) {
 934                         struct relay_viewer_stream *vstream;
 935
 936                         health_code_update();
 937
 938                         node = lttng_ht_iter_get_node_ulong(&iter);
 939                         if (!node) {
 940                                 continue;
 941                         }
 942                         stream = caa_container_of(node, struct relay_stream, stream_n);
 943                         if (stream->session != cmd->session) {
 944                                 continue;
 945                         }
 946
 947                         /*
 948                          * Don't send streams with no ctf_trace, they are not ready to be
 949                          * read.
 950                          */
 951                         if (!stream->ctf_trace) {
 952                                 continue;
 953                         }
 954
 955                         vstream = live_find_viewer_stream_by_id(stream->stream_handle);
 956                         if (!vstream) {
 957                                 ret = init_viewer_stream(stream, seek_last);
 958                                 if (ret < 0) {
 959                                         goto end_unlock;
 960                                 }
 961                         }
 962                         nb_streams++;
 963                 }
 964                 response.streams_count = htobe32(nb_streams);
 965         }
 966
 967 send_reply:
 968         health_code_update();
 969         ret = cmd->sock->ops->sendmsg(cmd->sock, &response, sizeof(response), 0);
 970         if (ret < 0) {
 971                 ERR("Relay sending viewer attach response");
 972                 goto end_unlock;
 973         }
 974         health_code_update();
 975
 976         /*
 977          * Unknown or busy session, just return gracefully, the viewer knows what
 978          * is happening.
 979          */
 980         if (!send_streams) {
 981                 ret = 0;
 982                 goto end_unlock;
 983         }
 984
 985         /* We should only be there if we have a session to attach to. */
 986         assert(session);
 987         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, node, node) {
 988                 health_code_update();
 989
 990                 node64 = lttng_ht_iter_get_node_u64(&iter);
 991                 if (!node64) {
 992                         continue;
 993                 }
 994                 viewer_stream = caa_container_of(node64, struct relay_viewer_stream,
 995                                 stream_n);
 996                 if (viewer_stream->session_id != cmd->session->id) {
 997                         continue;
 998                 }
 999
1000                 send_stream.id = htobe64(viewer_stream->stream_handle);
1001                 send_stream.ctf_trace_id = htobe64(viewer_stream->ctf_trace->id);
1002                 send_stream.metadata_flag = htobe32(viewer_stream->metadata_flag);
1003                 strncpy(send_stream.path_name, viewer_stream->path_name,
1004                                 sizeof(send_stream.path_name));
1005                 strncpy(send_stream.channel_name, viewer_stream->channel_name,
1006                                 sizeof(send_stream.channel_name));
1007
1008                 ret = cmd->sock->ops->sendmsg(cmd->sock, &send_stream,
1009                                 sizeof(send_stream), 0);
1010                 if (ret < 0) {
1011                         ERR("Relay sending stream %" PRIu64, viewer_stream->stream_handle);
1012                         goto end_unlock;
1013                 }
1014                 DBG("Sent stream %" PRIu64 " to viewer", viewer_stream->stream_handle);
1015         }
1016         ret = 0;
1017
1018 end_unlock:
1019         rcu_read_unlock();
1020 end_no_session:
1021 error:
1022         return ret;
1023 }
1024
1025 /*
1026  * Get viewer stream from stream id.
1027  *
1028  * RCU read side lock MUST be acquired.
1029  */
1030 struct relay_viewer_stream *live_find_viewer_stream_by_id(uint64_t stream_id)
1031 {
1032         struct lttng_ht_node_u64 *node;
1033         struct lttng_ht_iter iter;
1034         struct relay_viewer_stream *stream = NULL;
1035
1036         lttng_ht_lookup(viewer_streams_ht, &stream_id, &iter);
1037         node = lttng_ht_iter_get_node_u64(&iter);
1038         if (node == NULL) {
1039                 DBG("Relay viewer stream %" PRIu64 " not found", stream_id);
1040                 goto end;
1041         }
1042         stream = caa_container_of(node, struct relay_viewer_stream, stream_n);
1043
1044 end:
1045         return stream;
1046 }
1047
1048 /*
1049  * Send the next index for a stream.
1050  *
1051  * Return 0 on success or else a negative value.
1052  */
1053 static
1054 int viewer_get_next_index(struct relay_command *cmd,
1055                 struct lttng_ht *sessions_ht)
1056 {
1057         int ret;
1058         struct lttng_viewer_get_next_index request_index;
1059         struct lttng_viewer_index viewer_index;
1060         struct lttng_packet_index packet_index;
1061         struct relay_viewer_stream *vstream;
1062         struct relay_stream *rstream;
1063
1064         assert(cmd);
1065         assert(sessions_ht);
1066
1067         DBG("Viewer get next index");
1068
1069         if (cmd->version_check_done == 0) {
1070                 ERR("Trying to request index before version check");
1071                 ret = -1;
1072                 goto end_no_session;
1073         }
1074
1075         health_code_update();
1076         ret = cmd->sock->ops->recvmsg(cmd->sock, &request_index,
1077                         sizeof(request_index), 0);
1078         if (ret < 0 || ret != sizeof(request_index)) {
1079                 ret = -1;
1080                 ERR("Relay didn't receive the whole packet");
1081                 goto end;
1082         }
1083         health_code_update();
1084
1085         rcu_read_lock();
1086         vstream = live_find_viewer_stream_by_id(be64toh(request_index.stream_id));
1087         if (!vstream) {
1088                 ret = -1;
1089                 goto end_unlock;
1090         }
1091
1092         memset(&viewer_index, 0, sizeof(viewer_index));
1093
1094         /*
1095          * The viewer should not ask for index on metadata stream.
1096          */
1097         if (vstream->metadata_flag) {
1098                 viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1099                 goto send_reply;
1100         }
1101
1102         /* First time, we open the index file */
1103         if (vstream->index_read_fd < 0) {
1104                 ret = open_index(vstream);
1105                 if (ret == -ENOENT) {
1106                         /*
1107                          * The index is created only when the first data packet arrives, it
1108                          * might not be ready at the beginning of the session
1109                          */
1110                         viewer_index.status = htobe32(VIEWER_INDEX_RETRY);
1111                         goto send_reply;
1112                 } else if (ret < 0) {
1113                         viewer_index.status = htobe32(VIEWER_INDEX_ERR);
1114                         goto send_reply;
1115                 }
1116         }
1117
1118         rstream = relay_stream_find_by_id(vstream->stream_handle);
1119         if (rstream) {
1120                 if (vstream->abort_flag) {
1121                         /* Rotate on abort (overwrite). */
1122                         DBG("Viewer rotate because of overwrite");
1123                         ret = rotate_viewer_stream(vstream, rstream);
1124                         if (ret < 0) {
1125                                 goto end_unlock;
1126                         }
1127                 }
1128                 if (rstream->beacon_ts_end != -1ULL &&
1129                                 vstream->last_sent_index == rstream->total_index_received) {
1130                         viewer_index.status = htobe32(VIEWER_INDEX_INACTIVE);
1131                         viewer_index.timestamp_end = htobe64(rstream->beacon_ts_end);
1132                         goto send_reply;
1133                 }
1134                 /*
1135                  * Reader and writer are working in the same tracefile, so we care
1136                  * about the number of index received and sent. Otherwise, we read
1137                  * up to EOF.
1138                  */
1139                 pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1140                 if (rstream->tracefile_count_current == vstream->tracefile_count_current
1141                                 && rstream->total_index_received <= vstream->last_sent_index
1142                                 && !vstream->close_write_flag) {
1143                         pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1144                         /* No new index to send, retry later. */
1145                         viewer_index.status = htobe32(VIEWER_INDEX_RETRY);
1146                         goto send_reply;
1147                 }
1148                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1149         } else if (!rstream && vstream->close_write_flag &&
1150                         vstream->total_index_received == vstream->last_sent_index) {
1151                 /* Last index sent and current tracefile closed in write */
1152                 viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1153                 goto send_reply;
1154         } else {
1155                 vstream->close_write_flag = 1;
1156         }
1157
1158         if (!vstream->ctf_trace->metadata_received ||
1159                         vstream->ctf_trace->metadata_received >
1160                         vstream->ctf_trace->metadata_sent) {
1161                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1162         }
1163
1164         ret = lttng_read(vstream->index_read_fd, &packet_index,
1165                         sizeof(packet_index));
1166         if (ret < sizeof(packet_index)) {
1167                 /*
1168                  * The tracefile is closed in write, so we read up to EOF.
1169                  */
1170                 if (vstream->close_write_flag == 1) {
1171                         viewer_index.status = htobe32(VIEWER_INDEX_RETRY);
1172                         /* Rotate on normal EOF */
1173                         ret = rotate_viewer_stream(vstream, rstream);
1174                         if (ret < 0) {
1175                                 goto end_unlock;
1176                         }
1177                 } else {
1178                         /*
1179                          * If the read fd was closed by the streaming side, the
1180                          * abort_flag will be set to 1, otherwise it is an error.
1181                          */
1182                         if (vstream->abort_flag != 1) {
1183                                 PERROR("Relay reading index file");
1184                                 viewer_index.status = htobe32(VIEWER_INDEX_ERR);
1185                                 goto send_reply;
1186                         } else {
1187                                 viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1188                         }
1189                 }
1190                 goto send_reply;
1191         } else {
1192                 viewer_index.status = htobe32(VIEWER_INDEX_OK);
1193                 vstream->last_sent_index++;
1194         }
1195
1196         /*
1197          * Indexes are stored in big endian, no need to switch before sending.
1198          */
1199         viewer_index.offset = packet_index.offset;
1200         viewer_index.packet_size = packet_index.packet_size;
1201         viewer_index.content_size = packet_index.content_size;
1202         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1203         viewer_index.timestamp_end = packet_index.timestamp_end;
1204         viewer_index.events_discarded = packet_index.events_discarded;
1205         viewer_index.stream_id = packet_index.stream_id;
1206
1207 send_reply:
1208         viewer_index.flags = htobe32(viewer_index.flags);
1209         health_code_update();
1210         ret = cmd->sock->ops->sendmsg(cmd->sock, &viewer_index,
1211                         sizeof(viewer_index), 0);
1212         if (ret < 0) {
1213                 ERR("Relay index to viewer");
1214                 goto end_unlock;
1215         }
1216         health_code_update();
1217
1218         DBG("Index %" PRIu64 "for stream %" PRIu64 "sent",
1219                         vstream->last_sent_index, vstream->stream_handle);
1220
1221 end_unlock:
1222         rcu_read_unlock();
1223
1224 end_no_session:
1225 end:
1226         return ret;
1227 }
1228
1229 /*
1230  * Send the next index for a stream
1231  *
1232  * Return 0 on success or else a negative value.
1233  */
1234 static
1235 int viewer_get_packet(struct relay_command *cmd)
1236 {
1237         int ret, send_data = 0;
1238         char *data = NULL;
1239         uint32_t len = 0;
1240         ssize_t read_len;
1241         struct lttng_viewer_get_packet get_packet_info;
1242         struct lttng_viewer_trace_packet reply;
1243         struct relay_viewer_stream *stream;
1244
1245         assert(cmd);
1246
1247         DBG2("Relay get data packet");
1248
1249         if (cmd->version_check_done == 0) {
1250                 ERR("Trying to get packet before version check");
1251                 ret = -1;
1252                 goto end;
1253         }
1254
1255         health_code_update();
1256         ret = cmd->sock->ops->recvmsg(cmd->sock, &get_packet_info,
1257                         sizeof(get_packet_info), 0);
1258         if (ret < 0 || ret != sizeof(get_packet_info)) {
1259                 ret = -1;
1260                 ERR("Relay didn't receive the whole packet");
1261                 goto end;
1262         }
1263         health_code_update();
1264
1265         /* From this point on, the error label can be reached. */
1266         memset(&reply, 0, sizeof(reply));
1267
1268         rcu_read_lock();
1269         stream = live_find_viewer_stream_by_id(be64toh(get_packet_info.stream_id));
1270         if (!stream) {
1271                 goto error;
1272         }
1273         assert(stream->ctf_trace);
1274
1275         /*
1276          * First time we read this stream, we need open the tracefile, we should
1277          * only arrive here if an index has already been sent to the viewer, so the
1278          * tracefile must exist, if it does not it is a fatal error.
1279          */
1280         if (stream->read_fd < 0) {
1281                 char fullpath[PATH_MAX];
1282
1283                 if (stream->tracefile_count > 0) {
1284                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64, stream->path_name,
1285                                         stream->channel_name,
1286                                         stream->tracefile_count_current);
1287                 } else {
1288                         ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1289                                         stream->channel_name);
1290                 }
1291                 if (ret < 0) {
1292                         goto error;
1293                 }
1294                 ret = open(fullpath, O_RDONLY);
1295                 if (ret < 0) {
1296                         PERROR("Relay opening trace file");
1297                         goto error;
1298                 }
1299                 stream->read_fd = ret;
1300         }
1301
1302         if (!stream->ctf_trace->metadata_received ||
1303                         stream->ctf_trace->metadata_received >
1304                         stream->ctf_trace->metadata_sent) {
1305                 reply.status = htobe32(VIEWER_GET_PACKET_ERR);
1306                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1307                 goto send_reply;
1308         }
1309
1310         len = be32toh(get_packet_info.len);
1311         data = zmalloc(len);
1312         if (!data) {
1313                 PERROR("relay data zmalloc");
1314                 goto error;
1315         }
1316
1317         ret = lseek(stream->read_fd, be64toh(get_packet_info.offset), SEEK_SET);
1318         if (ret < 0) {
1319                 /*
1320                  * If the read fd was closed by the streaming side, the
1321                  * abort_flag will be set to 1, otherwise it is an error.
1322                  */
1323                 if (stream->abort_flag == 0) {
1324                         PERROR("lseek");
1325                         goto error;
1326                 }
1327                 reply.status = htobe32(VIEWER_GET_PACKET_EOF);
1328                 goto send_reply;
1329         }
1330         read_len = lttng_read(stream->read_fd, data, len);
1331         if (read_len < len) {
1332                 /*
1333                  * If the read fd was closed by the streaming side, the
1334                  * abort_flag will be set to 1, otherwise it is an error.
1335                  */
1336                 if (stream->abort_flag == 0) {
1337                         PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1338                                         stream->read_fd,
1339                                         be64toh(get_packet_info.offset));
1340                         goto error;
1341                 } else {
1342                         reply.status = htobe32(VIEWER_GET_PACKET_EOF);
1343                         goto send_reply;
1344                 }
1345         }
1346         reply.status = htobe32(VIEWER_GET_PACKET_OK);
1347         reply.len = htobe32(len);
1348         send_data = 1;
1349         goto send_reply;
1350
1351 error:
1352         reply.status = htobe32(VIEWER_GET_PACKET_ERR);
1353
1354 send_reply:
1355         reply.flags = htobe32(reply.flags);
1356
1357         health_code_update();
1358         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
1359         if (ret < 0) {
1360                 ERR("Relay data header to viewer");
1361                 goto end_unlock;
1362         }
1363         health_code_update();
1364
1365         if (send_data) {
1366                 health_code_update();
1367                 ret = cmd->sock->ops->sendmsg(cmd->sock, data, len, 0);
1368                 if (ret < 0) {
1369                         ERR("Relay send data to viewer");
1370                         goto end_unlock;
1371                 }
1372                 health_code_update();
1373         }
1374
1375         DBG("Sent %u bytes for stream %" PRIu64, len,
1376                         be64toh(get_packet_info.stream_id));
1377
1378 end_unlock:
1379         free(data);
1380         rcu_read_unlock();
1381
1382 end:
1383         return ret;
1384 }
1385
1386 /*
1387  * Send the session's metadata
1388  *
1389  * Return 0 on success else a negative value.
1390  */
1391 static
1392 int viewer_get_metadata(struct relay_command *cmd)
1393 {
1394         int ret = 0;
1395         ssize_t read_len;
1396         uint64_t len = 0;
1397         char *data = NULL;
1398         struct lttng_viewer_get_metadata request;
1399         struct lttng_viewer_metadata_packet reply;
1400         struct relay_viewer_stream *stream;
1401
1402         assert(cmd);
1403
1404         DBG("Relay get metadata");
1405
1406         if (cmd->version_check_done == 0) {
1407                 ERR("Trying to get metadata before version check");
1408                 ret = -1;
1409                 goto end;
1410         }
1411
1412         health_code_update();
1413         ret = cmd->sock->ops->recvmsg(cmd->sock, &request,
1414                         sizeof(request), 0);
1415         if (ret < 0 || ret != sizeof(request)) {
1416                 ret = -1;
1417                 ERR("Relay didn't receive the whole packet");
1418                 goto end;
1419         }
1420         health_code_update();
1421
1422         rcu_read_lock();
1423         stream = live_find_viewer_stream_by_id(be64toh(request.stream_id));
1424         if (!stream || !stream->metadata_flag) {
1425                 ERR("Invalid metadata stream");
1426                 goto error;
1427         }
1428         assert(stream->ctf_trace);
1429         assert(stream->ctf_trace->metadata_sent <=
1430                         stream->ctf_trace->metadata_received);
1431
1432         len = stream->ctf_trace->metadata_received -
1433                 stream->ctf_trace->metadata_sent;
1434         if (len == 0) {
1435                 reply.status = htobe32(VIEWER_NO_NEW_METADATA);
1436                 goto send_reply;
1437         }
1438
1439         /* first time, we open the metadata file */
1440         if (stream->read_fd < 0) {
1441                 char fullpath[PATH_MAX];
1442
1443                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1444                                 stream->channel_name);
1445                 if (ret < 0) {
1446                         goto error;
1447                 }
1448                 ret = open(fullpath, O_RDONLY);
1449                 if (ret < 0) {
1450                         PERROR("Relay opening metadata file");
1451                         goto error;
1452                 }
1453                 stream->read_fd = ret;
1454         }
1455
1456         reply.len = htobe64(len);
1457         data = zmalloc(len);
1458         if (!data) {
1459                 PERROR("viewer metadata zmalloc");
1460                 goto error;
1461         }
1462
1463         read_len = lttng_read(stream->read_fd, data, len);
1464         if (read_len < len) {
1465                 PERROR("Relay reading metadata file");
1466                 goto error;
1467         }
1468         stream->ctf_trace->metadata_sent += read_len;
1469         reply.status = htobe32(VIEWER_METADATA_OK);
1470         goto send_reply;
1471
1472 error:
1473         reply.status = htobe32(VIEWER_METADATA_ERR);
1474
1475 send_reply:
1476         health_code_update();
1477         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
1478         if (ret < 0) {
1479                 ERR("Relay data header to viewer");
1480                 goto end_unlock;
1481         }
1482         health_code_update();
1483
1484         if (len > 0) {
1485                 ret = cmd->sock->ops->sendmsg(cmd->sock, data, len, 0);
1486                 if (ret < 0) {
1487                         ERR("Relay send data to viewer");
1488                         goto end_unlock;
1489                 }
1490         }
1491
1492         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1493                         be64toh(request.stream_id));
1494
1495         DBG("Metadata sent");
1496
1497 end_unlock:
1498         free(data);
1499         rcu_read_unlock();
1500 end:
1501         return ret;
1502 }
1503
1504 /*
1505  * live_relay_unknown_command: send -1 if received unknown command
1506  */
1507 static
1508 void live_relay_unknown_command(struct relay_command *cmd)
1509 {
1510         struct lttcomm_relayd_generic_reply reply;
1511         int ret;
1512
1513         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1514         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
1515                         sizeof(struct lttcomm_relayd_generic_reply), 0);
1516         if (ret < 0) {
1517                 ERR("Relay sending unknown command");
1518         }
1519 }
1520
1521 /*
1522  * Process the commands received on the control socket
1523  */
1524 static
1525 int process_control(struct lttng_viewer_cmd *recv_hdr,
1526                 struct relay_command *cmd, struct lttng_ht *sessions_ht)
1527 {
1528         int ret = 0;
1529
1530         switch (be32toh(recv_hdr->cmd)) {
1531         case VIEWER_CONNECT:
1532                 ret = viewer_connect(cmd);
1533                 break;
1534         case VIEWER_LIST_SESSIONS:
1535                 ret = viewer_list_sessions(cmd, sessions_ht);
1536                 break;
1537         case VIEWER_ATTACH_SESSION:
1538                 ret = viewer_attach_session(cmd, sessions_ht);
1539                 break;
1540         case VIEWER_GET_NEXT_INDEX:
1541                 ret = viewer_get_next_index(cmd, sessions_ht);
1542                 break;
1543         case VIEWER_GET_PACKET:
1544                 ret = viewer_get_packet(cmd);
1545                 break;
1546         case VIEWER_GET_METADATA:
1547                 ret = viewer_get_metadata(cmd);
1548                 break;
1549         default:
1550                 ERR("Received unknown viewer command (%u)", be32toh(recv_hdr->cmd));
1551                 live_relay_unknown_command(cmd);
1552                 ret = -1;
1553                 goto end;
1554         }
1555
1556 end:
1557         return ret;
1558 }
1559
1560 static
1561 void cleanup_poll_connection(struct lttng_poll_event *events, int pollfd)
1562 {
1563         int ret;
1564
1565         assert(events);
1566
1567         lttng_poll_del(events, pollfd);
1568
1569         ret = close(pollfd);
1570         if (ret < 0) {
1571                 ERR("Closing pollfd %d", pollfd);
1572         }
1573 }
1574
1575 /*
1576  * Create and add connection to the given hash table.
1577  *
1578  * Return poll add value or else -1 on error.
1579  */
1580 static
1581 int add_connection(int fd, struct lttng_poll_event *events,
1582                 struct lttng_ht *relay_connections_ht)
1583 {
1584         int ret;
1585         struct relay_command *relay_connection;
1586
1587         assert(events);
1588         assert(relay_connections_ht);
1589
1590         relay_connection = zmalloc(sizeof(struct relay_command));
1591         if (relay_connection == NULL) {
1592                 PERROR("Relay command zmalloc");
1593                 goto error;
1594         }
1595
1596         ret = lttng_read(fd, relay_connection, sizeof(*relay_connection));
1597         if (ret < sizeof(*relay_connection)) {
1598                 PERROR("read relay cmd pipe");
1599                 goto error_read;
1600         }
1601
1602         lttng_ht_node_init_ulong(&relay_connection->sock_n,
1603                         (unsigned long) relay_connection->sock->fd);
1604         rcu_read_lock();
1605         lttng_ht_add_unique_ulong(relay_connections_ht,
1606                         &relay_connection->sock_n);
1607         rcu_read_unlock();
1608
1609         return lttng_poll_add(events, relay_connection->sock->fd,
1610                         LPOLLIN | LPOLLRDHUP);
1611
1612 error_read:
1613         free(relay_connection);
1614 error:
1615         return -1;
1616 }
1617
1618 static
1619 void deferred_free_connection(struct rcu_head *head)
1620 {
1621         struct relay_command *relay_connection =
1622                 caa_container_of(head, struct relay_command, rcu_node);
1623
1624         if (relay_connection->session &&
1625                         relay_connection->session->viewer_attached > 0) {
1626                 relay_connection->session->viewer_attached--;
1627         }
1628         lttcomm_destroy_sock(relay_connection->sock);
1629         free(relay_connection);
1630 }
1631
1632 static
1633 void deferred_free_viewer_stream(struct rcu_head *head)
1634 {
1635         struct relay_viewer_stream *stream =
1636                 caa_container_of(head, struct relay_viewer_stream, rcu_node);
1637
1638         if (stream->ctf_trace) {
1639                 uatomic_dec(&stream->ctf_trace->refcount);
1640                 assert(uatomic_read(&stream->ctf_trace->refcount) >= 0);
1641                 if (uatomic_read(&stream->ctf_trace->refcount) == 0) {
1642                         DBG("Freeing ctf_trace %" PRIu64, stream->ctf_trace->id);
1643                         free(stream->ctf_trace);
1644                 }
1645         }
1646
1647         free(stream->path_name);
1648         free(stream->channel_name);
1649         free(stream);
1650 }
1651
1652 static
1653 void viewer_del_streams(uint64_t session_id)
1654 {
1655         int ret;
1656         struct relay_viewer_stream *stream;
1657         struct lttng_ht_node_u64 *node;
1658         struct lttng_ht_iter iter;
1659
1660         rcu_read_lock();
1661         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, node, node) {
1662                 health_code_update();
1663
1664                 node = lttng_ht_iter_get_node_u64(&iter);
1665                 if (!node) {
1666                         continue;
1667                 }
1668
1669                 stream = caa_container_of(node, struct relay_viewer_stream, stream_n);
1670                 if (stream->session_id != session_id) {
1671                         continue;
1672                 }
1673
1674                 if (stream->read_fd >= 0) {
1675                         ret = close(stream->read_fd);
1676                         if (ret < 0) {
1677                                 PERROR("close read_fd");
1678                         }
1679                 }
1680                 if (stream->index_read_fd >= 0) {
1681                         ret = close(stream->index_read_fd);
1682                         if (ret < 0) {
1683                                 PERROR("close index_read_fd");
1684                         }
1685                 }
1686                 if (stream->metadata_flag && stream->ctf_trace) {
1687                         stream->ctf_trace->metadata_sent = 0;
1688                 }
1689                 ret = lttng_ht_del(viewer_streams_ht, &iter);
1690                 assert(!ret);
1691                 call_rcu(&stream->rcu_node, deferred_free_viewer_stream);
1692         }
1693         rcu_read_unlock();
1694 }
1695
1696 /*
1697  * Delete and free a connection.
1698  *
1699  * RCU read side lock MUST be acquired.
1700  */
1701 static
1702 void del_connection(struct lttng_ht *relay_connections_ht,
1703                 struct lttng_ht_iter *iter, struct relay_command *relay_connection)
1704 {
1705         int ret;
1706
1707         assert(relay_connections_ht);
1708         assert(iter);
1709         assert(relay_connection);
1710
1711         ret = lttng_ht_del(relay_connections_ht, iter);
1712         assert(!ret);
1713
1714         viewer_del_streams(relay_connection->session_id);
1715
1716         call_rcu(&relay_connection->rcu_node, deferred_free_connection);
1717 }
1718
1719 /*
1720  * This thread does the actual work
1721  */
1722 static
1723 void *thread_worker(void *data)
1724 {
1725         int ret, err = -1;
1726         uint32_t nb_fd;
1727         struct relay_command *relay_connection;
1728         struct lttng_poll_event events;
1729         struct lttng_ht *relay_connections_ht;
1730         struct lttng_ht_node_ulong *node;
1731         struct lttng_ht_iter iter;
1732         struct lttng_viewer_cmd recv_hdr;
1733         struct relay_local_data *relay_ctx = (struct relay_local_data *) data;
1734         struct lttng_ht *sessions_ht = relay_ctx->sessions_ht;
1735
1736         DBG("[thread] Live viewer relay worker started");
1737
1738         rcu_register_thread();
1739
1740         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1741
1742         /* table of connections indexed on socket */
1743         relay_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1744         if (!relay_connections_ht) {
1745                 goto relay_connections_ht_error;
1746         }
1747
1748         ret = create_thread_poll_set(&events, 2);
1749         if (ret < 0) {
1750                 goto error_poll_create;
1751         }
1752
1753         ret = lttng_poll_add(&events, live_relay_cmd_pipe[0], LPOLLIN | LPOLLRDHUP);
1754         if (ret < 0) {
1755                 goto error;
1756         }
1757
1758 restart:
1759         while (1) {
1760                 int i;
1761
1762                 health_code_update();
1763
1764                 /* Infinite blocking call, waiting for transmission */
1765                 DBG3("Relayd live viewer worker thread polling...");
1766                 health_poll_entry();
1767                 ret = lttng_poll_wait(&events, -1);
1768                 health_poll_exit();
1769                 if (ret < 0) {
1770                         /*
1771                          * Restart interrupted system call.
1772                          */
1773                         if (errno == EINTR) {
1774                                 goto restart;
1775                         }
1776                         goto error;
1777                 }
1778
1779                 nb_fd = ret;
1780
1781                 /*
1782                  * Process control. The control connection is prioritised so we don't
1783                  * starve it with high throughput tracing data on the data
1784                  * connection.
1785                  */
1786                 for (i = 0; i < nb_fd; i++) {
1787                         /* Fetch once the poll data */
1788                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1789                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1790
1791                         health_code_update();
1792
1793                         /* Thread quit pipe has been closed. Killing thread. */
1794                         ret = check_thread_quit_pipe(pollfd, revents);
1795                         if (ret) {
1796                                 err = 0;
1797                                 goto exit;
1798                         }
1799
1800                         /* Inspect the relay cmd pipe for new connection */
1801                         if (pollfd == live_relay_cmd_pipe[0]) {
1802                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1803                                         ERR("Relay live pipe error");
1804                                         goto error;
1805                                 } else if (revents & LPOLLIN) {
1806                                         DBG("Relay live viewer command received");
1807                                         ret = add_connection(live_relay_cmd_pipe[0],
1808                                                         &events, relay_connections_ht);
1809                                         if (ret < 0) {
1810                                                 goto error;
1811                                         }
1812                                 }
1813                         } else if (revents) {
1814                                 rcu_read_lock();
1815                                 lttng_ht_lookup(relay_connections_ht,
1816                                                 (void *)((unsigned long) pollfd), &iter);
1817                                 node = lttng_ht_iter_get_node_ulong(&iter);
1818                                 if (node == NULL) {
1819                                         DBG2("Relay viewer sock %d not found", pollfd);
1820                                         rcu_read_unlock();
1821                                         goto error;
1822                                 }
1823                                 relay_connection = caa_container_of(node, struct relay_command,
1824                                                 sock_n);
1825
1826                                 if (revents & (LPOLLERR)) {
1827                                         cleanup_poll_connection(&events, pollfd);
1828                                         del_connection(relay_connections_ht, &iter,
1829                                                         relay_connection);
1830                                 } else if (revents & (LPOLLHUP | LPOLLRDHUP)) {
1831                                         DBG("Viewer socket %d hung up", pollfd);
1832                                         cleanup_poll_connection(&events, pollfd);
1833                                         del_connection(relay_connections_ht, &iter,
1834                                                         relay_connection);
1835                                 } else if (revents & LPOLLIN) {
1836                                         ret = relay_connection->sock->ops->recvmsg(
1837                                                         relay_connection->sock, &recv_hdr,
1838                                                         sizeof(struct lttng_viewer_cmd),
1839                                                         0);
1840                                         /* connection closed */
1841                                         if (ret <= 0) {
1842                                                 cleanup_poll_connection(&events, pollfd);
1843                                                 del_connection(relay_connections_ht, &iter,
1844                                                                 relay_connection);
1845                                                 DBG("Viewer control connection closed with %d",
1846                                                                 pollfd);
1847                                         } else {
1848                                                 if (relay_connection->session) {
1849                                                         DBG2("Relay viewer worker receiving data for "
1850                                                                         "session: %" PRIu64,
1851                                                                         relay_connection->session->id);
1852                                                 }
1853                                                 ret = process_control(&recv_hdr, relay_connection,
1854                                                                 sessions_ht);
1855                                                 if (ret < 0) {
1856                                                         /* Clear the session on error. */
1857                                                         cleanup_poll_connection(&events, pollfd);
1858                                                         del_connection(relay_connections_ht, &iter,
1859                                                                         relay_connection);
1860                                                         DBG("Viewer connection closed with %d", pollfd);
1861                                                 }
1862                                         }
1863                                 }
1864                                 rcu_read_unlock();
1865                         }
1866                 }
1867         }
1868
1869 exit:
1870 error:
1871         lttng_poll_clean(&events);
1872
1873         /* empty the hash table and free the memory */
1874         rcu_read_lock();
1875         cds_lfht_for_each_entry(relay_connections_ht->ht, &iter.iter, node, node) {
1876                 health_code_update();
1877
1878                 node = lttng_ht_iter_get_node_ulong(&iter);
1879                 if (!node) {
1880                         continue;
1881                 }
1882
1883                 relay_connection = caa_container_of(node, struct relay_command,
1884                                 sock_n);
1885                 del_connection(relay_connections_ht, &iter, relay_connection);
1886         }
1887         rcu_read_unlock();
1888 error_poll_create:
1889         lttng_ht_destroy(relay_connections_ht);
1890 relay_connections_ht_error:
1891         /* Close relay cmd pipes */
1892         utils_close_pipe(live_relay_cmd_pipe);
1893         if (err) {
1894                 DBG("Viewer worker thread exited with error");
1895         }
1896         DBG("Viewer worker thread cleanup complete");
1897         if (err) {
1898                 health_error();
1899                 ERR("Health error occurred in %s", __func__);
1900         }
1901         health_unregister(health_relayd);
1902         stop_threads();
1903         rcu_unregister_thread();
1904         return NULL;
1905 }
1906
1907 /*
1908  * Create the relay command pipe to wake thread_manage_apps.
1909  * Closed in cleanup().
1910  */
1911 static int create_relay_cmd_pipe(void)
1912 {
1913         int ret;
1914
1915         ret = utils_create_pipe_cloexec(live_relay_cmd_pipe);
1916
1917         return ret;
1918 }
1919
1920 void live_stop_threads(void)
1921 {
1922         int ret;
1923         void *status;
1924
1925         stop_threads();
1926
1927         ret = pthread_join(live_listener_thread, &status);
1928         if (ret != 0) {
1929                 PERROR("pthread_join live listener");
1930                 goto error;     /* join error, exit without cleanup */
1931         }
1932
1933         ret = pthread_join(live_worker_thread, &status);
1934         if (ret != 0) {
1935                 PERROR("pthread_join live worker");
1936                 goto error;     /* join error, exit without cleanup */
1937         }
1938
1939         ret = pthread_join(live_dispatcher_thread, &status);
1940         if (ret != 0) {
1941                 PERROR("pthread_join live dispatcher");
1942                 goto error;     /* join error, exit without cleanup */
1943         }
1944
1945         cleanup();
1946
1947 error:
1948         return;
1949 }
1950
1951 /*
1952  * main
1953  */
1954 int live_start_threads(struct lttng_uri *uri,
1955                 struct relay_local_data *relay_ctx, int quit_pipe[2])
1956 {
1957         int ret = 0;
1958         void *status;
1959         int is_root;
1960
1961         assert(uri);
1962         live_uri = uri;
1963
1964         live_thread_quit_pipe[0] = quit_pipe[0];
1965         live_thread_quit_pipe[1] = quit_pipe[1];
1966
1967         /* Check if daemon is UID = 0 */
1968         is_root = !getuid();
1969
1970         if (!is_root) {
1971                 if (live_uri->port < 1024) {
1972                         ERR("Need to be root to use ports < 1024");
1973                         ret = -1;
1974                         goto exit;
1975                 }
1976         }
1977
1978         /* Setup the thread apps communication pipe. */
1979         if ((ret = create_relay_cmd_pipe()) < 0) {
1980                 goto exit;
1981         }
1982
1983         /* Init relay command queue. */
1984         cds_wfq_init(&viewer_cmd_queue.queue);
1985
1986         /* Set up max poll set size */
1987         lttng_poll_set_max_size();
1988
1989         /* Setup the dispatcher thread */
1990         ret = pthread_create(&live_dispatcher_thread, NULL,
1991                         thread_dispatcher, (void *) NULL);
1992         if (ret != 0) {
1993                 PERROR("pthread_create viewer dispatcher");
1994                 goto exit_dispatcher;
1995         }
1996
1997         /* Setup the worker thread */
1998         ret = pthread_create(&live_worker_thread, NULL,
1999                         thread_worker, relay_ctx);
2000         if (ret != 0) {
2001                 PERROR("pthread_create viewer worker");
2002                 goto exit_worker;
2003         }
2004
2005         /* Setup the listener thread */
2006         ret = pthread_create(&live_listener_thread, NULL,
2007                         thread_listener, (void *) NULL);
2008         if (ret != 0) {
2009                 PERROR("pthread_create viewer listener");
2010                 goto exit_listener;
2011         }
2012
2013         ret = 0;
2014         goto end;
2015
2016 exit_listener:
2017         ret = pthread_join(live_listener_thread, &status);
2018         if (ret != 0) {
2019                 PERROR("pthread_join live listener");
2020                 goto error;     /* join error, exit without cleanup */
2021         }
2022
2023 exit_worker:
2024         ret = pthread_join(live_worker_thread, &status);
2025         if (ret != 0) {
2026                 PERROR("pthread_join live worker");
2027                 goto error;     /* join error, exit without cleanup */
2028         }
2029
2030 exit_dispatcher:
2031         ret = pthread_join(live_dispatcher_thread, &status);
2032         if (ret != 0) {
2033                 PERROR("pthread_join live dispatcher");
2034                 goto error;     /* join error, exit without cleanup */
2035         }
2036
2037 exit:
2038         cleanup();
2039
2040 end:
2041 error:
2042         return ret;
2043 }