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 = -1;
 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 ctf_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 (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 653                 ERR("Invalid header magic");
 654                 ret = -1;
 655                 goto error;
 656         }
 657         if (be32toh(hdr.index_major) != CTF_INDEX_MAJOR ||
 658                         be32toh(hdr.index_minor) != CTF_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         viewer_stream->tracefile_count_last = -1ULL;
 702         if (seek_last) {
 703                 viewer_stream->tracefile_count_current =
 704                         stream->tracefile_count_current;
 705         } else {
 706                 viewer_stream->tracefile_count_current =
 707                         stream->oldest_tracefile_id;
 708         }
 709
 710         viewer_stream->ctf_trace = stream->ctf_trace;
 711         if (viewer_stream->metadata_flag) {
 712                 viewer_stream->ctf_trace->viewer_metadata_stream =
 713                         viewer_stream;
 714         }
 715         uatomic_inc(&viewer_stream->ctf_trace->refcount);
 716
 717         lttng_ht_node_init_u64(&viewer_stream->stream_n, stream->stream_handle);
 718         lttng_ht_add_unique_u64(viewer_streams_ht, &viewer_stream->stream_n);
 719
 720         viewer_stream->index_read_fd = -1;
 721         viewer_stream->read_fd = -1;
 722
 723         /*
 724          * This is to avoid a race between the initialization of this object and
 725          * the close of the given stream. If the stream is unable to find this
 726          * viewer stream when closing, this copy will at least take the latest
 727          * value.
 728          * We also need that for the seek_last.
 729          */
 730         viewer_stream->total_index_received = stream->total_index_received;
 731
 732         /*
 733          * If we never received an index for the current stream, delay
 734          * the opening of the index, otherwise open it right now.
 735          */
 736         if (viewer_stream->tracefile_count_current ==
 737                         stream->tracefile_count_current &&
 738                         viewer_stream->total_index_received == 0) {
 739                 viewer_stream->index_read_fd = -1;
 740         } else {
 741                 ret = open_index(viewer_stream);
 742                 if (ret < 0) {
 743                         goto error;
 744                 }
 745         }
 746
 747         if (seek_last && viewer_stream->index_read_fd > 0) {
 748                 ret = lseek(viewer_stream->index_read_fd,
 749                                 viewer_stream->total_index_received *
 750                                         sizeof(struct ctf_packet_index),
 751                                 SEEK_CUR);
 752                 if (ret < 0) {
 753                         goto error;
 754                 }
 755                 viewer_stream->last_sent_index =
 756                         viewer_stream->total_index_received;
 757         }
 758
 759         ret = 0;
 760
 761 error:
 762         return ret;
 763 }
 764
 765 /*
 766  * Rotate a stream to the next tracefile.
 767  *
 768  * Returns 0 on success, 1 on EOF, a negative value on error.
 769  */
 770 static
 771 int rotate_viewer_stream(struct relay_viewer_stream *viewer_stream,
 772                 struct relay_stream *stream)
 773 {
 774         int ret;
 775         uint64_t tracefile_id;
 776
 777         assert(viewer_stream);
 778
 779         tracefile_id = (viewer_stream->tracefile_count_current + 1) %
 780                 viewer_stream->tracefile_count;
 781         /*
 782          * Detect the last tracefile to open.
 783          */
 784         if (viewer_stream->tracefile_count_last != -1ULL &&
 785                         viewer_stream->tracefile_count_last ==
 786                         viewer_stream->tracefile_count_current) {
 787                 ret = 1;
 788                 goto end;
 789         }
 790
 791         if (stream) {
 792                 pthread_mutex_lock(&stream->viewer_stream_rotation_lock);
 793         }
 794         /*
 795          * The writer and the reader are not working in the same
 796          * tracefile, we can read up to EOF, we don't care about the
 797          * total_index_received.
 798          */
 799         if (!stream || (stream->tracefile_count_current != tracefile_id)) {
 800                 viewer_stream->close_write_flag = 1;
 801         } else {
 802                 /*
 803                  * We are opening a file that is still open in write, make
 804                  * sure we limit our reading to the number of indexes
 805                  * received.
 806                  */
 807                 viewer_stream->close_write_flag = 0;
 808                 if (stream) {
 809                         viewer_stream->total_index_received =
 810                                 stream->total_index_received;
 811                 }
 812         }
 813         viewer_stream->tracefile_count_current = tracefile_id;
 814
 815         ret = close(viewer_stream->index_read_fd);
 816         if (ret < 0) {
 817                 PERROR("close index file %d",
 818                                 viewer_stream->index_read_fd);
 819         }
 820         viewer_stream->index_read_fd = -1;
 821         ret = close(viewer_stream->read_fd);
 822         if (ret < 0) {
 823                 PERROR("close tracefile %d",
 824                                 viewer_stream->read_fd);
 825         }
 826         viewer_stream->read_fd = -1;
 827
 828         pthread_mutex_lock(&viewer_stream->overwrite_lock);
 829         viewer_stream->abort_flag = 0;
 830         pthread_mutex_unlock(&viewer_stream->overwrite_lock);
 831
 832         viewer_stream->index_read_fd = -1;
 833         viewer_stream->read_fd = -1;
 834
 835         if (stream) {
 836                 pthread_mutex_unlock(&stream->viewer_stream_rotation_lock);
 837         }
 838         ret = open_index(viewer_stream);
 839         if (ret < 0) {
 840                 goto error;
 841         }
 842
 843         ret = 0;
 844
 845 end:
 846 error:
 847         return ret;
 848 }
 849
 850 /*
 851  * Send the viewer the list of current sessions.
 852  */
 853 static
 854 int viewer_attach_session(struct relay_command *cmd,
 855                 struct lttng_ht *sessions_ht)
 856 {
 857         int ret, send_streams = 0, nb_streams = 0;
 858         struct lttng_viewer_attach_session_request request;
 859         struct lttng_viewer_attach_session_response response;
 860         struct lttng_viewer_stream send_stream;
 861         struct relay_stream *stream;
 862         struct relay_viewer_stream *viewer_stream;
 863         struct lttng_ht_node_ulong *node;
 864         struct lttng_ht_node_u64 *node64;
 865         struct lttng_ht_iter iter;
 866         struct relay_session *session;
 867         int seek_last = 0;
 868
 869         assert(cmd);
 870         assert(sessions_ht);
 871
 872         DBG("Attach session received");
 873
 874         if (cmd->version_check_done == 0) {
 875                 ERR("Trying to attach session before version check");
 876                 ret = -1;
 877                 goto end_no_session;
 878         }
 879
 880         health_code_update();
 881
 882         ret = cmd->sock->ops->recvmsg(cmd->sock, &request, sizeof(request), 0);
 883         if (ret < 0 || ret != sizeof(request)) {
 884                 if (ret == 0) {
 885                         /* Orderly shutdown. Not necessary to print an error. */
 886                         DBG("Socket %d did an orderly shutdown", cmd->sock->fd);
 887                 } else {
 888                         ERR("Relay failed to receive the attach parameters.");
 889                 }
 890                 ret = -1;
 891                 goto error;
 892         }
 893
 894         health_code_update();
 895
 896         rcu_read_lock();
 897         lttng_ht_lookup(sessions_ht,
 898                         (void *)((unsigned long) be64toh(request.session_id)), &iter);
 899         node = lttng_ht_iter_get_node_ulong(&iter);
 900         if (node == NULL) {
 901                 DBG("Relay session %" PRIu64 " not found",
 902                                 be64toh(request.session_id));
 903                 response.status = htobe32(VIEWER_ATTACH_UNK);
 904                 goto send_reply;
 905         }
 906
 907         session = caa_container_of(node, struct relay_session, session_n);
 908         if (cmd->session_id == session->id) {
 909                 /* Same viewer already attached, just send the stream list. */
 910                 send_streams = 1;
 911                 response.status = htobe32(VIEWER_ATTACH_OK);
 912         } else if (session->viewer_attached != 0) {
 913                 DBG("Already a viewer attached");
 914                 response.status = htobe32(VIEWER_ATTACH_ALREADY);
 915                 goto send_reply;
 916         } else if (session->live_timer == 0) {
 917                 DBG("Not live session");
 918                 response.status = htobe32(VIEWER_ATTACH_NOT_LIVE);
 919                 goto send_reply;
 920         } else {
 921                 session->viewer_attached++;
 922                 send_streams = 1;
 923                 response.status = htobe32(VIEWER_ATTACH_OK);
 924                 cmd->session_id = session->id;
 925                 cmd->session = session;
 926         }
 927
 928         switch (be32toh(request.seek)) {
 929         case VIEWER_SEEK_BEGINNING:
 930                 /* Default behaviour. */
 931                 break;
 932         case VIEWER_SEEK_LAST:
 933                 seek_last = 1;
 934                 break;
 935         default:
 936                 ERR("Wrong seek parameter");
 937                 response.status = htobe32(VIEWER_ATTACH_SEEK_ERR);
 938                 send_streams = 0;
 939                 goto send_reply;
 940         }
 941
 942         if (send_streams) {
 943                 /* We should only be there if we have a session to attach to. */
 944                 assert(session);
 945
 946                 /*
 947                  * Fill the viewer_streams_ht to count the number of streams
 948                  * ready to be sent and avoid concurrency issues on the
 949                  * relay_streams_ht and don't rely on a total session stream count.
 950                  */
 951                 cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, node, node) {
 952                         struct relay_viewer_stream *vstream;
 953
 954                         health_code_update();
 955
 956                         node = lttng_ht_iter_get_node_ulong(&iter);
 957                         if (!node) {
 958                                 continue;
 959                         }
 960                         stream = caa_container_of(node, struct relay_stream, stream_n);
 961                         if (stream->session != cmd->session) {
 962                                 continue;
 963                         }
 964
 965                         /*
 966                          * Don't send streams with no ctf_trace, they are not ready to be
 967                          * read.
 968                          */
 969                         if (!stream->ctf_trace) {
 970                                 continue;
 971                         }
 972
 973                         vstream = live_find_viewer_stream_by_id(stream->stream_handle);
 974                         if (!vstream) {
 975                                 ret = init_viewer_stream(stream, seek_last);
 976                                 if (ret < 0) {
 977                                         goto end_unlock;
 978                                 }
 979                         }
 980                         nb_streams++;
 981                 }
 982                 response.streams_count = htobe32(nb_streams);
 983         }
 984
 985 send_reply:
 986         health_code_update();
 987         ret = cmd->sock->ops->sendmsg(cmd->sock, &response, sizeof(response), 0);
 988         if (ret < 0) {
 989                 ERR("Relay sending viewer attach response");
 990                 goto end_unlock;
 991         }
 992         health_code_update();
 993
 994         /*
 995          * Unknown or empty session, just return gracefully, the viewer knows what
 996          * is happening.
 997          */
 998         if (!send_streams || !nb_streams) {
 999                 ret = 0;
1000                 goto end_unlock;
1001         }
1002
1003         /* We should only be there if we have a session to attach to. */
1004         assert(session);
1005         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, node, node) {
1006                 health_code_update();
1007
1008                 node64 = lttng_ht_iter_get_node_u64(&iter);
1009                 if (!node64) {
1010                         continue;
1011                 }
1012                 viewer_stream = caa_container_of(node64, struct relay_viewer_stream,
1013                                 stream_n);
1014                 if (viewer_stream->session_id != cmd->session->id) {
1015                         continue;
1016                 }
1017
1018                 send_stream.id = htobe64(viewer_stream->stream_handle);
1019                 send_stream.ctf_trace_id = htobe64(viewer_stream->ctf_trace->id);
1020                 send_stream.metadata_flag = htobe32(viewer_stream->metadata_flag);
1021                 strncpy(send_stream.path_name, viewer_stream->path_name,
1022                                 sizeof(send_stream.path_name));
1023                 strncpy(send_stream.channel_name, viewer_stream->channel_name,
1024                                 sizeof(send_stream.channel_name));
1025
1026                 ret = cmd->sock->ops->sendmsg(cmd->sock, &send_stream,
1027                                 sizeof(send_stream), 0);
1028                 if (ret < 0) {
1029                         ERR("Relay sending stream %" PRIu64, viewer_stream->stream_handle);
1030                         goto end_unlock;
1031                 }
1032                 DBG("Sent stream %" PRIu64 " to viewer", viewer_stream->stream_handle);
1033         }
1034         ret = 0;
1035
1036 end_unlock:
1037         rcu_read_unlock();
1038 end_no_session:
1039 error:
1040         return ret;
1041 }
1042
1043 /*
1044  * Get viewer stream from stream id.
1045  *
1046  * RCU read side lock MUST be acquired.
1047  */
1048 struct relay_viewer_stream *live_find_viewer_stream_by_id(uint64_t stream_id)
1049 {
1050         struct lttng_ht_node_u64 *node;
1051         struct lttng_ht_iter iter;
1052         struct relay_viewer_stream *stream = NULL;
1053
1054         lttng_ht_lookup(viewer_streams_ht, &stream_id, &iter);
1055         node = lttng_ht_iter_get_node_u64(&iter);
1056         if (node == NULL) {
1057                 DBG("Relay viewer stream %" PRIu64 " not found", stream_id);
1058                 goto end;
1059         }
1060         stream = caa_container_of(node, struct relay_viewer_stream, stream_n);
1061
1062 end:
1063         return stream;
1064 }
1065
1066 static
1067 void deferred_free_viewer_stream(struct rcu_head *head)
1068 {
1069         struct relay_viewer_stream *stream =
1070                 caa_container_of(head, struct relay_viewer_stream, rcu_node);
1071
1072         free(stream->path_name);
1073         free(stream->channel_name);
1074         free(stream);
1075 }
1076
1077 static
1078 void delete_viewer_stream(struct relay_viewer_stream *vstream)
1079 {
1080         int delret;
1081         struct lttng_ht_iter iter;
1082
1083         iter.iter.node = &vstream->stream_n.node;
1084         delret = lttng_ht_del(viewer_streams_ht, &iter);
1085         assert(!delret);
1086 }
1087
1088 static
1089 void destroy_viewer_stream(struct relay_viewer_stream *vstream)
1090 {
1091         unsigned long ret_ref;
1092         int ret;
1093
1094         assert(vstream);
1095         ret_ref = uatomic_add_return(&vstream->ctf_trace->refcount, -1);
1096         assert(ret_ref >= 0);
1097
1098         if (vstream->read_fd >= 0) {
1099                 ret = close(vstream->read_fd);
1100                 if (ret < 0) {
1101                         PERROR("close read_fd");
1102                 }
1103         }
1104         if (vstream->index_read_fd >= 0) {
1105                 ret = close(vstream->index_read_fd);
1106                 if (ret < 0) {
1107                         PERROR("close index_read_fd");
1108                 }
1109         }
1110
1111         /*
1112          * If the only stream left in the HT is the metadata stream,
1113          * we need to remove it because we won't detect a EOF for this
1114          * stream.
1115          */
1116         if (ret_ref == 1 && vstream->ctf_trace->metadata_stream) {
1117                 destroy_viewer_stream(vstream->ctf_trace->viewer_metadata_stream);
1118                 vstream->ctf_trace->metadata_stream = NULL;
1119                 DBG("Freeing ctf_trace %" PRIu64, vstream->ctf_trace->id);
1120                 /*
1121                  * The streaming-side is already closed and we can't receive a new
1122                  * stream concurrently at this point (since the session is being
1123                  * destroyed), so when we detect the refcount equals 0, we are the
1124                  * only owners of the ctf_trace and we can free it ourself.
1125                  */
1126                 free(vstream->ctf_trace);
1127         }
1128
1129         call_rcu(&vstream->rcu_node, deferred_free_viewer_stream);
1130 }
1131
1132 /*
1133  * Send the next index for a stream.
1134  *
1135  * Return 0 on success or else a negative value.
1136  */
1137 static
1138 int viewer_get_next_index(struct relay_command *cmd,
1139                 struct lttng_ht *sessions_ht)
1140 {
1141         int ret;
1142         struct lttng_viewer_get_next_index request_index;
1143         struct lttng_viewer_index viewer_index;
1144         struct ctf_packet_index packet_index;
1145         struct relay_viewer_stream *vstream;
1146         struct relay_stream *rstream;
1147
1148         assert(cmd);
1149         assert(sessions_ht);
1150
1151         DBG("Viewer get next index");
1152
1153         if (cmd->version_check_done == 0) {
1154                 ERR("Trying to request index before version check");
1155                 ret = -1;
1156                 goto end_no_session;
1157         }
1158
1159         health_code_update();
1160         ret = cmd->sock->ops->recvmsg(cmd->sock, &request_index,
1161                         sizeof(request_index), 0);
1162         if (ret < 0 || ret != sizeof(request_index)) {
1163                 ret = -1;
1164                 ERR("Relay didn't receive the whole packet");
1165                 goto end;
1166         }
1167         health_code_update();
1168
1169         rcu_read_lock();
1170         vstream = live_find_viewer_stream_by_id(be64toh(request_index.stream_id));
1171         if (!vstream) {
1172                 ret = -1;
1173                 goto end_unlock;
1174         }
1175
1176         memset(&viewer_index, 0, sizeof(viewer_index));
1177
1178         /*
1179          * The viewer should not ask for index on metadata stream.
1180          */
1181         if (vstream->metadata_flag) {
1182                 viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1183                 goto send_reply;
1184         }
1185
1186         /* First time, we open the index file */
1187         if (vstream->index_read_fd < 0) {
1188                 ret = open_index(vstream);
1189                 if (ret == -ENOENT) {
1190                         /*
1191                          * The index is created only when the first data packet arrives, it
1192                          * might not be ready at the beginning of the session
1193                          */
1194                         viewer_index.status = htobe32(VIEWER_INDEX_RETRY);
1195                         goto send_reply;
1196                 } else if (ret < 0) {
1197                         viewer_index.status = htobe32(VIEWER_INDEX_ERR);
1198                         goto send_reply;
1199                 }
1200         }
1201
1202         rstream = relay_stream_find_by_id(vstream->stream_handle);
1203         if (rstream) {
1204                 if (vstream->abort_flag) {
1205                         /* Rotate on abort (overwrite). */
1206                         DBG("Viewer rotate because of overwrite");
1207                         ret = rotate_viewer_stream(vstream, rstream);
1208                         if (ret < 0) {
1209                                 goto end_unlock;
1210                         } else if (ret == 1) {
1211                                 viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1212                                 delete_viewer_stream(vstream);
1213                                 destroy_viewer_stream(vstream);
1214                                 goto send_reply;
1215                         }
1216                 }
1217                 pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1218                 if (rstream->tracefile_count_current == vstream->tracefile_count_current) {
1219                         if (rstream->beacon_ts_end != -1ULL &&
1220                                 vstream->last_sent_index == rstream->total_index_received) {
1221                                 viewer_index.status = htobe32(VIEWER_INDEX_INACTIVE);
1222                                 viewer_index.timestamp_end = htobe64(rstream->beacon_ts_end);
1223                                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1224                                 goto send_reply;
1225                         /*
1226                          * Reader and writer are working in the same tracefile, so we care
1227                          * about the number of index received and sent. Otherwise, we read
1228                          * up to EOF.
1229                          */
1230                         } else if (rstream->total_index_received <= vstream->last_sent_index
1231                                         && !vstream->close_write_flag) {
1232                                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1233                                 /* No new index to send, retry later. */
1234                                 viewer_index.status = htobe32(VIEWER_INDEX_RETRY);
1235                                 goto send_reply;
1236                         }
1237                 }
1238                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1239         } else if (!rstream && vstream->close_write_flag &&
1240                         vstream->total_index_received == vstream->last_sent_index) {
1241                 /* Last index sent and current tracefile closed in write */
1242                 viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1243                 delete_viewer_stream(vstream);
1244                 destroy_viewer_stream(vstream);
1245                 goto send_reply;
1246         } else {
1247                 vstream->close_write_flag = 1;
1248         }
1249
1250         if (!vstream->ctf_trace->metadata_received ||
1251                         vstream->ctf_trace->metadata_received >
1252                         vstream->ctf_trace->metadata_sent) {
1253                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1254         }
1255
1256         pthread_mutex_lock(&vstream->overwrite_lock);
1257         if (vstream->abort_flag) {
1258                 /*
1259                  * The file is being overwritten by the writer, we cannot
1260                  * use it.
1261                  */
1262                 viewer_index.status = htobe32(VIEWER_INDEX_RETRY);
1263                 pthread_mutex_unlock(&vstream->overwrite_lock);
1264                 ret = rotate_viewer_stream(vstream, rstream);
1265                 if (ret < 0) {
1266                         goto end_unlock;
1267                 } else if (ret == 1) {
1268                         viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1269                         delete_viewer_stream(vstream);
1270                         destroy_viewer_stream(vstream);
1271                         goto send_reply;
1272                 }
1273                 goto send_reply;
1274         }
1275         ret = lttng_read(vstream->index_read_fd, &packet_index,
1276                         sizeof(packet_index));
1277         pthread_mutex_unlock(&vstream->overwrite_lock);
1278         if (ret < sizeof(packet_index)) {
1279                 /*
1280                  * The tracefile is closed in write, so we read up to EOF.
1281                  */
1282                 if (vstream->close_write_flag == 1) {
1283                         viewer_index.status = htobe32(VIEWER_INDEX_RETRY);
1284                         /* Rotate on normal EOF */
1285                         ret = rotate_viewer_stream(vstream, rstream);
1286                         if (ret < 0) {
1287                                 goto end_unlock;
1288                         } else if (ret == 1) {
1289                                 viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1290                                 delete_viewer_stream(vstream);
1291                                 destroy_viewer_stream(vstream);
1292                                 goto send_reply;
1293                         }
1294                 } else {
1295                         PERROR("Relay reading index file %d",
1296                                         vstream->index_read_fd);
1297                         viewer_index.status = htobe32(VIEWER_INDEX_ERR);
1298                 }
1299                 goto send_reply;
1300         } else {
1301                 viewer_index.status = htobe32(VIEWER_INDEX_OK);
1302                 vstream->last_sent_index++;
1303         }
1304
1305         /*
1306          * Indexes are stored in big endian, no need to switch before sending.
1307          */
1308         viewer_index.offset = packet_index.offset;
1309         viewer_index.packet_size = packet_index.packet_size;
1310         viewer_index.content_size = packet_index.content_size;
1311         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1312         viewer_index.timestamp_end = packet_index.timestamp_end;
1313         viewer_index.events_discarded = packet_index.events_discarded;
1314         viewer_index.stream_id = packet_index.stream_id;
1315
1316 send_reply:
1317         viewer_index.flags = htobe32(viewer_index.flags);
1318         health_code_update();
1319         ret = cmd->sock->ops->sendmsg(cmd->sock, &viewer_index,
1320                         sizeof(viewer_index), 0);
1321         if (ret < 0) {
1322                 ERR("Relay index to viewer");
1323                 goto end_unlock;
1324         }
1325         health_code_update();
1326
1327         DBG("Index %" PRIu64 "for stream %" PRIu64 "sent",
1328                         vstream->last_sent_index, vstream->stream_handle);
1329
1330 end_unlock:
1331         rcu_read_unlock();
1332
1333 end_no_session:
1334 end:
1335         return ret;
1336 }
1337
1338 /*
1339  * Send the next index for a stream
1340  *
1341  * Return 0 on success or else a negative value.
1342  */
1343 static
1344 int viewer_get_packet(struct relay_command *cmd)
1345 {
1346         int ret, send_data = 0;
1347         char *data = NULL;
1348         uint32_t len = 0;
1349         ssize_t read_len;
1350         struct lttng_viewer_get_packet get_packet_info;
1351         struct lttng_viewer_trace_packet reply;
1352         struct relay_viewer_stream *stream;
1353
1354         assert(cmd);
1355
1356         DBG2("Relay get data packet");
1357
1358         if (cmd->version_check_done == 0) {
1359                 ERR("Trying to get packet before version check");
1360                 ret = -1;
1361                 goto end;
1362         }
1363
1364         health_code_update();
1365         ret = cmd->sock->ops->recvmsg(cmd->sock, &get_packet_info,
1366                         sizeof(get_packet_info), 0);
1367         if (ret < 0 || ret != sizeof(get_packet_info)) {
1368                 ret = -1;
1369                 ERR("Relay didn't receive the whole packet");
1370                 goto end;
1371         }
1372         health_code_update();
1373
1374         /* From this point on, the error label can be reached. */
1375         memset(&reply, 0, sizeof(reply));
1376
1377         rcu_read_lock();
1378         stream = live_find_viewer_stream_by_id(be64toh(get_packet_info.stream_id));
1379         if (!stream) {
1380                 goto error;
1381         }
1382         assert(stream->ctf_trace);
1383
1384         /*
1385          * First time we read this stream, we need open the tracefile, we should
1386          * only arrive here if an index has already been sent to the viewer, so the
1387          * tracefile must exist, if it does not it is a fatal error.
1388          */
1389         if (stream->read_fd < 0) {
1390                 char fullpath[PATH_MAX];
1391
1392                 if (stream->tracefile_count > 0) {
1393                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64, stream->path_name,
1394                                         stream->channel_name,
1395                                         stream->tracefile_count_current);
1396                 } else {
1397                         ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1398                                         stream->channel_name);
1399                 }
1400                 if (ret < 0) {
1401                         goto error;
1402                 }
1403                 ret = open(fullpath, O_RDONLY);
1404                 if (ret < 0) {
1405                         PERROR("Relay opening trace file");
1406                         goto error;
1407                 }
1408                 stream->read_fd = ret;
1409         }
1410
1411         if (!stream->ctf_trace->metadata_received ||
1412                         stream->ctf_trace->metadata_received >
1413                         stream->ctf_trace->metadata_sent) {
1414                 reply.status = htobe32(VIEWER_GET_PACKET_ERR);
1415                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1416                 goto send_reply;
1417         }
1418
1419         len = be32toh(get_packet_info.len);
1420         data = zmalloc(len);
1421         if (!data) {
1422                 PERROR("relay data zmalloc");
1423                 goto error;
1424         }
1425
1426         ret = lseek(stream->read_fd, be64toh(get_packet_info.offset), SEEK_SET);
1427         if (ret < 0) {
1428                 /*
1429                  * If the read fd was closed by the streaming side, the
1430                  * abort_flag will be set to 1, otherwise it is an error.
1431                  */
1432                 if (stream->abort_flag == 0) {
1433                         PERROR("lseek");
1434                         goto error;
1435                 }
1436                 reply.status = htobe32(VIEWER_GET_PACKET_EOF);
1437                 goto send_reply;
1438         }
1439         read_len = lttng_read(stream->read_fd, data, len);
1440         if (read_len < len) {
1441                 /*
1442                  * If the read fd was closed by the streaming side, the
1443                  * abort_flag will be set to 1, otherwise it is an error.
1444                  */
1445                 if (stream->abort_flag == 0) {
1446                         PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1447                                         stream->read_fd,
1448                                         be64toh(get_packet_info.offset));
1449                         goto error;
1450                 } else {
1451                         reply.status = htobe32(VIEWER_GET_PACKET_EOF);
1452                         goto send_reply;
1453                 }
1454         }
1455         reply.status = htobe32(VIEWER_GET_PACKET_OK);
1456         reply.len = htobe32(len);
1457         send_data = 1;
1458         goto send_reply;
1459
1460 error:
1461         reply.status = htobe32(VIEWER_GET_PACKET_ERR);
1462
1463 send_reply:
1464         reply.flags = htobe32(reply.flags);
1465
1466         health_code_update();
1467         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
1468         if (ret < 0) {
1469                 ERR("Relay data header to viewer");
1470                 goto end_unlock;
1471         }
1472         health_code_update();
1473
1474         if (send_data) {
1475                 health_code_update();
1476                 ret = cmd->sock->ops->sendmsg(cmd->sock, data, len, 0);
1477                 if (ret < 0) {
1478                         ERR("Relay send data to viewer");
1479                         goto end_unlock;
1480                 }
1481                 health_code_update();
1482         }
1483
1484         DBG("Sent %u bytes for stream %" PRIu64, len,
1485                         be64toh(get_packet_info.stream_id));
1486
1487 end_unlock:
1488         free(data);
1489         rcu_read_unlock();
1490
1491 end:
1492         return ret;
1493 }
1494
1495 /*
1496  * Send the session's metadata
1497  *
1498  * Return 0 on success else a negative value.
1499  */
1500 static
1501 int viewer_get_metadata(struct relay_command *cmd)
1502 {
1503         int ret = 0;
1504         ssize_t read_len;
1505         uint64_t len = 0;
1506         char *data = NULL;
1507         struct lttng_viewer_get_metadata request;
1508         struct lttng_viewer_metadata_packet reply;
1509         struct relay_viewer_stream *stream;
1510
1511         assert(cmd);
1512
1513         DBG("Relay get metadata");
1514
1515         if (cmd->version_check_done == 0) {
1516                 ERR("Trying to get metadata before version check");
1517                 ret = -1;
1518                 goto end;
1519         }
1520
1521         health_code_update();
1522         ret = cmd->sock->ops->recvmsg(cmd->sock, &request,
1523                         sizeof(request), 0);
1524         if (ret < 0 || ret != sizeof(request)) {
1525                 ret = -1;
1526                 ERR("Relay didn't receive the whole packet");
1527                 goto end;
1528         }
1529         health_code_update();
1530
1531         rcu_read_lock();
1532         stream = live_find_viewer_stream_by_id(be64toh(request.stream_id));
1533         if (!stream || !stream->metadata_flag) {
1534                 ERR("Invalid metadata stream");
1535                 goto error;
1536         }
1537         assert(stream->ctf_trace);
1538         assert(stream->ctf_trace->metadata_sent <=
1539                         stream->ctf_trace->metadata_received);
1540
1541         len = stream->ctf_trace->metadata_received -
1542                 stream->ctf_trace->metadata_sent;
1543         if (len == 0) {
1544                 reply.status = htobe32(VIEWER_NO_NEW_METADATA);
1545                 goto send_reply;
1546         }
1547
1548         /* first time, we open the metadata file */
1549         if (stream->read_fd < 0) {
1550                 char fullpath[PATH_MAX];
1551
1552                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1553                                 stream->channel_name);
1554                 if (ret < 0) {
1555                         goto error;
1556                 }
1557                 ret = open(fullpath, O_RDONLY);
1558                 if (ret < 0) {
1559                         PERROR("Relay opening metadata file");
1560                         goto error;
1561                 }
1562                 stream->read_fd = ret;
1563         }
1564
1565         reply.len = htobe64(len);
1566         data = zmalloc(len);
1567         if (!data) {
1568                 PERROR("viewer metadata zmalloc");
1569                 goto error;
1570         }
1571
1572         read_len = lttng_read(stream->read_fd, data, len);
1573         if (read_len < len) {
1574                 PERROR("Relay reading metadata file");
1575                 goto error;
1576         }
1577         stream->ctf_trace->metadata_sent += read_len;
1578         reply.status = htobe32(VIEWER_METADATA_OK);
1579         goto send_reply;
1580
1581 error:
1582         reply.status = htobe32(VIEWER_METADATA_ERR);
1583
1584 send_reply:
1585         health_code_update();
1586         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
1587         if (ret < 0) {
1588                 ERR("Relay data header to viewer");
1589                 goto end_unlock;
1590         }
1591         health_code_update();
1592
1593         if (len > 0) {
1594                 ret = cmd->sock->ops->sendmsg(cmd->sock, data, len, 0);
1595                 if (ret < 0) {
1596                         ERR("Relay send data to viewer");
1597                         goto end_unlock;
1598                 }
1599         }
1600
1601         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1602                         be64toh(request.stream_id));
1603
1604         DBG("Metadata sent");
1605
1606 end_unlock:
1607         free(data);
1608         rcu_read_unlock();
1609 end:
1610         return ret;
1611 }
1612
1613 /*
1614  * live_relay_unknown_command: send -1 if received unknown command
1615  */
1616 static
1617 void live_relay_unknown_command(struct relay_command *cmd)
1618 {
1619         struct lttcomm_relayd_generic_reply reply;
1620         int ret;
1621
1622         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1623         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
1624                         sizeof(struct lttcomm_relayd_generic_reply), 0);
1625         if (ret < 0) {
1626                 ERR("Relay sending unknown command");
1627         }
1628 }
1629
1630 /*
1631  * Process the commands received on the control socket
1632  */
1633 static
1634 int process_control(struct lttng_viewer_cmd *recv_hdr,
1635                 struct relay_command *cmd, struct lttng_ht *sessions_ht)
1636 {
1637         int ret = 0;
1638
1639         switch (be32toh(recv_hdr->cmd)) {
1640         case VIEWER_CONNECT:
1641                 ret = viewer_connect(cmd);
1642                 break;
1643         case VIEWER_LIST_SESSIONS:
1644                 ret = viewer_list_sessions(cmd, sessions_ht);
1645                 break;
1646         case VIEWER_ATTACH_SESSION:
1647                 ret = viewer_attach_session(cmd, sessions_ht);
1648                 break;
1649         case VIEWER_GET_NEXT_INDEX:
1650                 ret = viewer_get_next_index(cmd, sessions_ht);
1651                 break;
1652         case VIEWER_GET_PACKET:
1653                 ret = viewer_get_packet(cmd);
1654                 break;
1655         case VIEWER_GET_METADATA:
1656                 ret = viewer_get_metadata(cmd);
1657                 break;
1658         default:
1659                 ERR("Received unknown viewer command (%u)", be32toh(recv_hdr->cmd));
1660                 live_relay_unknown_command(cmd);
1661                 ret = -1;
1662                 goto end;
1663         }
1664
1665 end:
1666         return ret;
1667 }
1668
1669 static
1670 void cleanup_poll_connection(struct lttng_poll_event *events, int pollfd)
1671 {
1672         int ret;
1673
1674         assert(events);
1675
1676         lttng_poll_del(events, pollfd);
1677
1678         ret = close(pollfd);
1679         if (ret < 0) {
1680                 ERR("Closing pollfd %d", pollfd);
1681         }
1682 }
1683
1684 /*
1685  * Create and add connection to the given hash table.
1686  *
1687  * Return poll add value or else -1 on error.
1688  */
1689 static
1690 int add_connection(int fd, struct lttng_poll_event *events,
1691                 struct lttng_ht *relay_connections_ht)
1692 {
1693         int ret;
1694         struct relay_command *relay_connection;
1695
1696         assert(events);
1697         assert(relay_connections_ht);
1698
1699         relay_connection = zmalloc(sizeof(struct relay_command));
1700         if (relay_connection == NULL) {
1701                 PERROR("Relay command zmalloc");
1702                 goto error;
1703         }
1704
1705         ret = lttng_read(fd, relay_connection, sizeof(*relay_connection));
1706         if (ret < sizeof(*relay_connection)) {
1707                 PERROR("read relay cmd pipe");
1708                 goto error_read;
1709         }
1710
1711         lttng_ht_node_init_ulong(&relay_connection->sock_n,
1712                         (unsigned long) relay_connection->sock->fd);
1713         rcu_read_lock();
1714         lttng_ht_add_unique_ulong(relay_connections_ht,
1715                         &relay_connection->sock_n);
1716         rcu_read_unlock();
1717
1718         return lttng_poll_add(events, relay_connection->sock->fd,
1719                         LPOLLIN | LPOLLRDHUP);
1720
1721 error_read:
1722         free(relay_connection);
1723 error:
1724         return -1;
1725 }
1726
1727 static
1728 void deferred_free_connection(struct rcu_head *head)
1729 {
1730         struct relay_command *relay_connection =
1731                 caa_container_of(head, struct relay_command, rcu_node);
1732
1733         if (relay_connection->session &&
1734                         relay_connection->session->viewer_attached > 0) {
1735                 relay_connection->session->viewer_attached--;
1736         }
1737         lttcomm_destroy_sock(relay_connection->sock);
1738         free(relay_connection);
1739 }
1740
1741 /*
1742  * Delete all streams for a specific session ID.
1743  */
1744 static
1745 void viewer_del_streams(uint64_t session_id)
1746 {
1747         struct relay_viewer_stream *stream;
1748         struct lttng_ht_iter iter;
1749
1750         rcu_read_lock();
1751         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, stream,
1752                         stream_n.node) {
1753                 health_code_update();
1754
1755                 if (stream->session_id != session_id) {
1756                         continue;
1757                 }
1758
1759                 delete_viewer_stream(stream);
1760                 assert(stream->ctf_trace);
1761
1762                 if (stream->metadata_flag) {
1763                         /*
1764                          * The metadata viewer stream is destroyed once the refcount on the
1765                          * ctf trace goes to 0 in the destroy stream function thus there is
1766                          * no explicit call to that function here.
1767                          */
1768                         stream->ctf_trace->metadata_sent = 0;
1769                         stream->ctf_trace->viewer_metadata_stream = NULL;
1770                 } else {
1771                         destroy_viewer_stream(stream);
1772                 }
1773         }
1774         rcu_read_unlock();
1775 }
1776
1777 /*
1778  * Delete and free a connection.
1779  *
1780  * RCU read side lock MUST be acquired.
1781  */
1782 static
1783 void del_connection(struct lttng_ht *relay_connections_ht,
1784                 struct lttng_ht_iter *iter, struct relay_command *relay_connection)
1785 {
1786         int ret;
1787
1788         assert(relay_connections_ht);
1789         assert(iter);
1790         assert(relay_connection);
1791
1792         DBG("Cleaning connection of session ID %" PRIu64,
1793                         relay_connection->session_id);
1794
1795         ret = lttng_ht_del(relay_connections_ht, iter);
1796         assert(!ret);
1797
1798         viewer_del_streams(relay_connection->session_id);
1799
1800         call_rcu(&relay_connection->rcu_node, deferred_free_connection);
1801 }
1802
1803 /*
1804  * This thread does the actual work
1805  */
1806 static
1807 void *thread_worker(void *data)
1808 {
1809         int ret, err = -1;
1810         uint32_t nb_fd;
1811         struct relay_command *relay_connection;
1812         struct lttng_poll_event events;
1813         struct lttng_ht *relay_connections_ht;
1814         struct lttng_ht_node_ulong *node;
1815         struct lttng_ht_iter iter;
1816         struct lttng_viewer_cmd recv_hdr;
1817         struct relay_local_data *relay_ctx = (struct relay_local_data *) data;
1818         struct lttng_ht *sessions_ht = relay_ctx->sessions_ht;
1819
1820         DBG("[thread] Live viewer relay worker started");
1821
1822         rcu_register_thread();
1823
1824         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1825
1826         /* table of connections indexed on socket */
1827         relay_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1828         if (!relay_connections_ht) {
1829                 goto relay_connections_ht_error;
1830         }
1831
1832         ret = create_thread_poll_set(&events, 2);
1833         if (ret < 0) {
1834                 goto error_poll_create;
1835         }
1836
1837         ret = lttng_poll_add(&events, live_relay_cmd_pipe[0], LPOLLIN | LPOLLRDHUP);
1838         if (ret < 0) {
1839                 goto error;
1840         }
1841
1842 restart:
1843         while (1) {
1844                 int i;
1845
1846                 health_code_update();
1847
1848                 /* Infinite blocking call, waiting for transmission */
1849                 DBG3("Relayd live viewer worker thread polling...");
1850                 health_poll_entry();
1851                 ret = lttng_poll_wait(&events, -1);
1852                 health_poll_exit();
1853                 if (ret < 0) {
1854                         /*
1855                          * Restart interrupted system call.
1856                          */
1857                         if (errno == EINTR) {
1858                                 goto restart;
1859                         }
1860                         goto error;
1861                 }
1862
1863                 nb_fd = ret;
1864
1865                 /*
1866                  * Process control. The control connection is prioritised so we don't
1867                  * starve it with high throughput tracing data on the data
1868                  * connection.
1869                  */
1870                 for (i = 0; i < nb_fd; i++) {
1871                         /* Fetch once the poll data */
1872                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1873                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1874
1875                         health_code_update();
1876
1877                         /* Thread quit pipe has been closed. Killing thread. */
1878                         ret = check_thread_quit_pipe(pollfd, revents);
1879                         if (ret) {
1880                                 err = 0;
1881                                 goto exit;
1882                         }
1883
1884                         /* Inspect the relay cmd pipe for new connection */
1885                         if (pollfd == live_relay_cmd_pipe[0]) {
1886                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1887                                         ERR("Relay live pipe error");
1888                                         goto error;
1889                                 } else if (revents & LPOLLIN) {
1890                                         DBG("Relay live viewer command received");
1891                                         ret = add_connection(live_relay_cmd_pipe[0],
1892                                                         &events, relay_connections_ht);
1893                                         if (ret < 0) {
1894                                                 goto error;
1895                                         }
1896                                 }
1897                         } else if (revents) {
1898                                 rcu_read_lock();
1899                                 lttng_ht_lookup(relay_connections_ht,
1900                                                 (void *)((unsigned long) pollfd), &iter);
1901                                 node = lttng_ht_iter_get_node_ulong(&iter);
1902                                 if (node == NULL) {
1903                                         DBG2("Relay viewer sock %d not found", pollfd);
1904                                         rcu_read_unlock();
1905                                         goto error;
1906                                 }
1907                                 relay_connection = caa_container_of(node, struct relay_command,
1908                                                 sock_n);
1909
1910                                 if (revents & (LPOLLERR)) {
1911                                         cleanup_poll_connection(&events, pollfd);
1912                                         del_connection(relay_connections_ht, &iter,
1913                                                         relay_connection);
1914                                 } else if (revents & (LPOLLHUP | LPOLLRDHUP)) {
1915                                         DBG("Viewer socket %d hung up", pollfd);
1916                                         cleanup_poll_connection(&events, pollfd);
1917                                         del_connection(relay_connections_ht, &iter,
1918                                                         relay_connection);
1919                                 } else if (revents & LPOLLIN) {
1920                                         ret = relay_connection->sock->ops->recvmsg(
1921                                                         relay_connection->sock, &recv_hdr,
1922                                                         sizeof(struct lttng_viewer_cmd),
1923                                                         0);
1924                                         /* connection closed */
1925                                         if (ret <= 0) {
1926                                                 cleanup_poll_connection(&events, pollfd);
1927                                                 del_connection(relay_connections_ht, &iter,
1928                                                                 relay_connection);
1929                                                 DBG("Viewer control connection closed with %d",
1930                                                                 pollfd);
1931                                         } else {
1932                                                 if (relay_connection->session) {
1933                                                         DBG2("Relay viewer worker receiving data for "
1934                                                                         "session: %" PRIu64,
1935                                                                         relay_connection->session->id);
1936                                                 }
1937                                                 ret = process_control(&recv_hdr, relay_connection,
1938                                                                 sessions_ht);
1939                                                 if (ret < 0) {
1940                                                         /* Clear the session on error. */
1941                                                         cleanup_poll_connection(&events, pollfd);
1942                                                         del_connection(relay_connections_ht, &iter,
1943                                                                         relay_connection);
1944                                                         DBG("Viewer connection closed with %d", pollfd);
1945                                                 }
1946                                         }
1947                                 }
1948                                 rcu_read_unlock();
1949                         }
1950                 }
1951         }
1952
1953 exit:
1954 error:
1955         lttng_poll_clean(&events);
1956
1957         /* empty the hash table and free the memory */
1958         rcu_read_lock();
1959         cds_lfht_for_each_entry(relay_connections_ht->ht, &iter.iter, node, node) {
1960                 health_code_update();
1961
1962                 node = lttng_ht_iter_get_node_ulong(&iter);
1963                 if (!node) {
1964                         continue;
1965                 }
1966
1967                 relay_connection = caa_container_of(node, struct relay_command,
1968                                 sock_n);
1969                 del_connection(relay_connections_ht, &iter, relay_connection);
1970         }
1971         rcu_read_unlock();
1972 error_poll_create:
1973         lttng_ht_destroy(relay_connections_ht);
1974 relay_connections_ht_error:
1975         /* Close relay cmd pipes */
1976         utils_close_pipe(live_relay_cmd_pipe);
1977         if (err) {
1978                 DBG("Viewer worker thread exited with error");
1979         }
1980         DBG("Viewer worker thread cleanup complete");
1981         if (err) {
1982                 health_error();
1983                 ERR("Health error occurred in %s", __func__);
1984         }
1985         health_unregister(health_relayd);
1986         stop_threads();
1987         rcu_unregister_thread();
1988         return NULL;
1989 }
1990
1991 /*
1992  * Create the relay command pipe to wake thread_manage_apps.
1993  * Closed in cleanup().
1994  */
1995 static int create_relay_cmd_pipe(void)
1996 {
1997         int ret;
1998
1999         ret = utils_create_pipe_cloexec(live_relay_cmd_pipe);
2000
2001         return ret;
2002 }
2003
2004 void live_stop_threads(void)
2005 {
2006         int ret;
2007         void *status;
2008
2009         stop_threads();
2010
2011         ret = pthread_join(live_listener_thread, &status);
2012         if (ret != 0) {
2013                 PERROR("pthread_join live listener");
2014                 goto error;     /* join error, exit without cleanup */
2015         }
2016
2017         ret = pthread_join(live_worker_thread, &status);
2018         if (ret != 0) {
2019                 PERROR("pthread_join live worker");
2020                 goto error;     /* join error, exit without cleanup */
2021         }
2022
2023         ret = pthread_join(live_dispatcher_thread, &status);
2024         if (ret != 0) {
2025                 PERROR("pthread_join live dispatcher");
2026                 goto error;     /* join error, exit without cleanup */
2027         }
2028
2029         cleanup();
2030
2031 error:
2032         return;
2033 }
2034
2035 /*
2036  * main
2037  */
2038 int live_start_threads(struct lttng_uri *uri,
2039                 struct relay_local_data *relay_ctx, int quit_pipe[2])
2040 {
2041         int ret = 0;
2042         void *status;
2043         int is_root;
2044
2045         assert(uri);
2046         live_uri = uri;
2047
2048         live_thread_quit_pipe[0] = quit_pipe[0];
2049         live_thread_quit_pipe[1] = quit_pipe[1];
2050
2051         /* Check if daemon is UID = 0 */
2052         is_root = !getuid();
2053
2054         if (!is_root) {
2055                 if (live_uri->port < 1024) {
2056                         ERR("Need to be root to use ports < 1024");
2057                         ret = -1;
2058                         goto exit;
2059                 }
2060         }
2061
2062         /* Setup the thread apps communication pipe. */
2063         if ((ret = create_relay_cmd_pipe()) < 0) {
2064                 goto exit;
2065         }
2066
2067         /* Init relay command queue. */
2068         cds_wfq_init(&viewer_cmd_queue.queue);
2069
2070         /* Set up max poll set size */
2071         lttng_poll_set_max_size();
2072
2073         /* Setup the dispatcher thread */
2074         ret = pthread_create(&live_dispatcher_thread, NULL,
2075                         thread_dispatcher, (void *) NULL);
2076         if (ret != 0) {
2077                 PERROR("pthread_create viewer dispatcher");
2078                 goto exit_dispatcher;
2079         }
2080
2081         /* Setup the worker thread */
2082         ret = pthread_create(&live_worker_thread, NULL,
2083                         thread_worker, relay_ctx);
2084         if (ret != 0) {
2085                 PERROR("pthread_create viewer worker");
2086                 goto exit_worker;
2087         }
2088
2089         /* Setup the listener thread */
2090         ret = pthread_create(&live_listener_thread, NULL,
2091                         thread_listener, (void *) NULL);
2092         if (ret != 0) {
2093                 PERROR("pthread_create viewer listener");
2094                 goto exit_listener;
2095         }
2096
2097         ret = 0;
2098         goto end;
2099
2100 exit_listener:
2101         ret = pthread_join(live_listener_thread, &status);
2102         if (ret != 0) {
2103                 PERROR("pthread_join live listener");
2104                 goto error;     /* join error, exit without cleanup */
2105         }
2106
2107 exit_worker:
2108         ret = pthread_join(live_worker_thread, &status);
2109         if (ret != 0) {
2110                 PERROR("pthread_join live worker");
2111                 goto error;     /* join error, exit without cleanup */
2112         }
2113
2114 exit_dispatcher:
2115         ret = pthread_join(live_dispatcher_thread, &status);
2116         if (ret != 0) {
2117                 PERROR("pthread_join live dispatcher");
2118                 goto error;     /* join error, exit without cleanup */
2119         }
2120
2121 exit:
2122         cleanup();
2123
2124 end:
2125 error:
2126         return ret;
2127 }