src/bin/lttng-relayd/live.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _GNU_SOURCE
  21 #include <getopt.h>
  22 #include <grp.h>
  23 #include <limits.h>
  24 #include <pthread.h>
  25 #include <signal.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <sys/mman.h>
  30 #include <sys/mount.h>
  31 #include <sys/resource.h>
  32 #include <sys/socket.h>
  33 #include <sys/stat.h>
  34 #include <sys/types.h>
  35 #include <sys/wait.h>
  36 #include <inttypes.h>
  37 #include <urcu/futex.h>
  38 #include <urcu/uatomic.h>
  39 #include <urcu/rculist.h>
  40 #include <unistd.h>
  41 #include <fcntl.h>
  42 #include <config.h>
  43
  44 #include <lttng/lttng.h>
  45 #include <common/common.h>
  46 #include <common/compat/poll.h>
  47 #include <common/compat/socket.h>
  48 #include <common/compat/endian.h>
  49 #include <common/defaults.h>
  50 #include <common/futex.h>
  51 #include <common/index/index.h>
  52 #include <common/sessiond-comm/sessiond-comm.h>
  53 #include <common/sessiond-comm/inet.h>
  54 #include <common/sessiond-comm/relayd.h>
  55 #include <common/uri.h>
  56 #include <common/utils.h>
  57
  58 #include "cmd.h"
  59 #include "live.h"
  60 #include "lttng-relayd.h"
  61 #include "utils.h"
  62 #include "health-relayd.h"
  63 #include "testpoint.h"
  64 #include "viewer-stream.h"
  65 #include "stream.h"
  66 #include "session.h"
  67 #include "ctf-trace.h"
  68 #include "connection.h"
  69 #include "viewer-session.h"
  70
  71 #define SESSION_BUF_DEFAULT_COUNT       16
  72
  73 static struct lttng_uri *live_uri;
  74
  75 /*
  76  * This pipe is used to inform the worker thread that a command is queued and
  77  * ready to be processed.
  78  */
  79 static int live_conn_pipe[2] = { -1, -1 };
  80
  81 /* Shared between threads */
  82 static int live_dispatch_thread_exit;
  83
  84 static pthread_t live_listener_thread;
  85 static pthread_t live_dispatcher_thread;
  86 static pthread_t live_worker_thread;
  87
  88 /*
  89  * Relay command queue.
  90  *
  91  * The live_thread_listener and live_thread_dispatcher communicate with this
  92  * queue.
  93  */
  94 static struct relay_conn_queue viewer_conn_queue;
  95
  96 static uint64_t last_relay_viewer_session_id;
  97 static pthread_mutex_t last_relay_viewer_session_id_lock =
  98                 PTHREAD_MUTEX_INITIALIZER;
  99
 100 /*
 101  * Cleanup the daemon
 102  */
 103 static
 104 void cleanup_relayd_live(void)
 105 {
 106         DBG("Cleaning up");
 107
 108         free(live_uri);
 109 }
 110
 111 /*
 112  * Receive a request buffer using a given socket, destination allocated buffer
 113  * of length size.
 114  *
 115  * Return the size of the received message or else a negative value on error
 116  * with errno being set by recvmsg() syscall.
 117  */
 118 static
 119 ssize_t recv_request(struct lttcomm_sock *sock, void *buf, size_t size)
 120 {
 121         ssize_t ret;
 122
 123         ret = sock->ops->recvmsg(sock, buf, size, 0);
 124         if (ret < 0 || ret != size) {
 125                 if (ret == 0) {
 126                         /* Orderly shutdown. Not necessary to print an error. */
 127                         DBG("Socket %d did an orderly shutdown", sock->fd);
 128                 } else {
 129                         ERR("Relay failed to receive request.");
 130                 }
 131                 ret = -1;
 132         }
 133
 134         return ret;
 135 }
 136
 137 /*
 138  * Send a response buffer using a given socket, source allocated buffer of
 139  * length size.
 140  *
 141  * Return the size of the sent message or else a negative value on error with
 142  * errno being set by sendmsg() syscall.
 143  */
 144 static
 145 ssize_t send_response(struct lttcomm_sock *sock, void *buf, size_t size)
 146 {
 147         ssize_t ret;
 148
 149         ret = sock->ops->sendmsg(sock, buf, size, 0);
 150         if (ret < 0) {
 151                 ERR("Relayd failed to send response.");
 152         }
 153
 154         return ret;
 155 }
 156
 157 /*
 158  * Atomically check if new streams got added in one of the sessions attached
 159  * and reset the flag to 0.
 160  *
 161  * Returns 1 if new streams got added, 0 if nothing changed, a negative value
 162  * on error.
 163  */
 164 static
 165 int check_new_streams(struct relay_connection *conn)
 166 {
 167         struct relay_session *session;
 168         unsigned long current_val;
 169         int ret = 0;
 170
 171         if (!conn->viewer_session) {
 172                 goto end;
 173         }
 174         rcu_read_lock();
 175         cds_list_for_each_entry_rcu(session,
 176                         &conn->viewer_session->session_list,
 177                         viewer_session_node) {
 178                 if (!session_get(session)) {
 179                         continue;
 180                 }
 181                 current_val = uatomic_cmpxchg(&session->new_streams, 1, 0);
 182                 ret = current_val;
 183                 session_put(session);
 184                 if (ret == 1) {
 185                         goto end;
 186                 }
 187         }
 188 end:
 189         rcu_read_unlock();
 190         return ret;
 191 }
 192
 193 /*
 194  * Send viewer streams to the given socket. The ignore_sent_flag indicates if
 195  * this function should ignore the sent flag or not.
 196  *
 197  * Return 0 on success or else a negative value.
 198  */
 199 static
 200 ssize_t send_viewer_streams(struct lttcomm_sock *sock,
 201                 struct relay_session *session, unsigned int ignore_sent_flag)
 202 {
 203         ssize_t ret;
 204         struct lttng_viewer_stream send_stream;
 205         struct lttng_ht_iter iter;
 206         struct relay_viewer_stream *vstream;
 207
 208         rcu_read_lock();
 209
 210         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
 211                         stream_n.node) {
 212                 struct ctf_trace *ctf_trace;
 213
 214                 health_code_update();
 215
 216                 if (!viewer_stream_get(vstream)) {
 217                         continue;
 218                 }
 219
 220                 pthread_mutex_lock(&vstream->stream->lock);
 221                 /* Ignore if not the same session. */
 222                 if (vstream->stream->trace->session->id != session->id ||
 223                                 (!ignore_sent_flag && vstream->sent_flag)) {
 224                         pthread_mutex_unlock(&vstream->stream->lock);
 225                         viewer_stream_put(vstream);
 226                         continue;
 227                 }
 228
 229                 ctf_trace = vstream->stream->trace;
 230                 send_stream.id = htobe64(vstream->stream->stream_handle);
 231                 send_stream.ctf_trace_id = htobe64(ctf_trace->id);
 232                 send_stream.metadata_flag = htobe32(
 233                                 vstream->stream->is_metadata);
 234                 strncpy(send_stream.path_name, vstream->path_name,
 235                                 sizeof(send_stream.path_name));
 236                 strncpy(send_stream.channel_name, vstream->channel_name,
 237                                 sizeof(send_stream.channel_name));
 238
 239                 DBG("Sending stream %" PRIu64 " to viewer",
 240                                 vstream->stream->stream_handle);
 241                 vstream->sent_flag = 1;
 242                 pthread_mutex_unlock(&vstream->stream->lock);
 243
 244                 ret = send_response(sock, &send_stream, sizeof(send_stream));
 245                 viewer_stream_put(vstream);
 246                 if (ret < 0) {
 247                         goto end_unlock;
 248                 }
 249         }
 250
 251         ret = 0;
 252
 253 end_unlock:
 254         rcu_read_unlock();
 255         return ret;
 256 }
 257
 258 /*
 259  * Create every viewer stream possible for the given session with the seek
 260  * type. Three counters *can* be return which are in order the total amount of
 261  * viewer stream of the session, the number of unsent stream and the number of
 262  * stream created. Those counters can be NULL and thus will be ignored.
 263  *
 264  * Return 0 on success or else a negative value.
 265  */
 266 static
 267 int make_viewer_streams(struct relay_session *session,
 268                 enum lttng_viewer_seek seek_t, uint32_t *nb_total, uint32_t *nb_unsent,
 269                 uint32_t *nb_created, bool *closed)
 270 {
 271         int ret;
 272         struct lttng_ht_iter iter;
 273         struct ctf_trace *ctf_trace;
 274
 275         assert(session);
 276
 277         /*
 278          * Hold the session lock to ensure that we see either none or
 279          * all initial streams for a session, but no intermediate state.
 280          */
 281         pthread_mutex_lock(&session->lock);
 282
 283         if (session->connection_closed) {
 284                 *closed = true;
 285         }
 286
 287         /*
 288          * Create viewer streams for relay streams that are ready to be
 289          * used for a the given session id only.
 290          */
 291         rcu_read_lock();
 292         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 293                         node.node) {
 294                 struct relay_stream *stream;
 295
 296                 health_code_update();
 297
 298                 if (!ctf_trace_get(ctf_trace)) {
 299                         continue;
 300                 }
 301
 302                 cds_list_for_each_entry_rcu(stream, &ctf_trace->stream_list, stream_node) {
 303                         struct relay_viewer_stream *vstream;
 304
 305                         if (!stream_get(stream)) {
 306                                 continue;
 307                         }
 308                         /*
 309                          * stream published is protected by the session lock.
 310                          */
 311                         if (!stream->published) {
 312                                 goto next;
 313                         }
 314                         vstream = viewer_stream_get_by_id(stream->stream_handle);
 315                         if (!vstream) {
 316                                 vstream = viewer_stream_create(stream, seek_t);
 317                                 if (!vstream) {
 318                                         ret = -1;
 319                                         ctf_trace_put(ctf_trace);
 320                                         stream_put(stream);
 321                                         goto error_unlock;
 322                                 }
 323
 324                                 if (nb_created) {
 325                                         /* Update number of created stream counter. */
 326                                         (*nb_created)++;
 327                                 }
 328                                 /*
 329                                  * Ensure a self-reference is preserved even
 330                                  * after we have put our local reference.
 331                                  */
 332                                 viewer_stream_get(vstream);
 333                         } else {
 334                                 if (!vstream->sent_flag && nb_unsent) {
 335                                         /* Update number of unsent stream counter. */
 336                                         (*nb_unsent)++;
 337                                 }
 338                         }
 339                         /* Update number of total stream counter. */
 340                         if (nb_total) {
 341                                 if (stream->is_metadata) {
 342                                         if (!stream->closed ||
 343                                                         stream->metadata_received > vstream->metadata_sent) {
 344                                                 (*nb_total)++;
 345                                         }
 346                                 } else {
 347                                         if (!stream->closed ||
 348                                                 !(((int64_t) (stream->prev_seq - stream->last_net_seq_num)) >= 0)) {
 349
 350                                                 (*nb_total)++;
 351                                         }
 352                                 }
 353                         }
 354                         /* Put local reference. */
 355                         viewer_stream_put(vstream);
 356                 next:
 357                         stream_put(stream);
 358                 }
 359                 ctf_trace_put(ctf_trace);
 360         }
 361
 362         ret = 0;
 363
 364 error_unlock:
 365         rcu_read_unlock();
 366         pthread_mutex_unlock(&session->lock);
 367         return ret;
 368 }
 369
 370 int relayd_live_stop(void)
 371 {
 372         /* Stop dispatch thread */
 373         CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
 374         futex_nto1_wake(&viewer_conn_queue.futex);
 375         return 0;
 376 }
 377
 378 /*
 379  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 380  */
 381 static
 382 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 383 {
 384         int ret;
 385
 386         if (events == NULL || size == 0) {
 387                 ret = -1;
 388                 goto error;
 389         }
 390
 391         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 392         if (ret < 0) {
 393                 goto error;
 394         }
 395
 396         /* Add quit pipe */
 397         ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
 398         if (ret < 0) {
 399                 goto error;
 400         }
 401
 402         return 0;
 403
 404 error:
 405         return ret;
 406 }
 407
 408 /*
 409  * Check if the thread quit pipe was triggered.
 410  *
 411  * Return 1 if it was triggered else 0;
 412  */
 413 static
 414 int check_thread_quit_pipe(int fd, uint32_t events)
 415 {
 416         if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
 417                 return 1;
 418         }
 419
 420         return 0;
 421 }
 422
 423 /*
 424  * Create and init socket from uri.
 425  */
 426 static
 427 struct lttcomm_sock *init_socket(struct lttng_uri *uri)
 428 {
 429         int ret;
 430         struct lttcomm_sock *sock = NULL;
 431
 432         sock = lttcomm_alloc_sock_from_uri(uri);
 433         if (sock == NULL) {
 434                 ERR("Allocating socket");
 435                 goto error;
 436         }
 437
 438         ret = lttcomm_create_sock(sock);
 439         if (ret < 0) {
 440                 goto error;
 441         }
 442         DBG("Listening on sock %d for live", sock->fd);
 443
 444         ret = sock->ops->bind(sock);
 445         if (ret < 0) {
 446                 goto error;
 447         }
 448
 449         ret = sock->ops->listen(sock, -1);
 450         if (ret < 0) {
 451                 goto error;
 452
 453         }
 454
 455         return sock;
 456
 457 error:
 458         if (sock) {
 459                 lttcomm_destroy_sock(sock);
 460         }
 461         return NULL;
 462 }
 463
 464 /*
 465  * This thread manages the listening for new connections on the network
 466  */
 467 static
 468 void *thread_listener(void *data)
 469 {
 470         int i, ret, pollfd, err = -1;
 471         uint32_t revents, nb_fd;
 472         struct lttng_poll_event events;
 473         struct lttcomm_sock *live_control_sock;
 474
 475         DBG("[thread] Relay live listener started");
 476
 477         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_LISTENER);
 478
 479         health_code_update();
 480
 481         live_control_sock = init_socket(live_uri);
 482         if (!live_control_sock) {
 483                 goto error_sock_control;
 484         }
 485
 486         /* Pass 2 as size here for the thread quit pipe and control sockets. */
 487         ret = create_thread_poll_set(&events, 2);
 488         if (ret < 0) {
 489                 goto error_create_poll;
 490         }
 491
 492         /* Add the control socket */
 493         ret = lttng_poll_add(&events, live_control_sock->fd, LPOLLIN | LPOLLRDHUP);
 494         if (ret < 0) {
 495                 goto error_poll_add;
 496         }
 497
 498         lttng_relay_notify_ready();
 499
 500         if (testpoint(relayd_thread_live_listener)) {
 501                 goto error_testpoint;
 502         }
 503
 504         while (1) {
 505                 health_code_update();
 506
 507                 DBG("Listener accepting live viewers connections");
 508
 509 restart:
 510                 health_poll_entry();
 511                 ret = lttng_poll_wait(&events, -1);
 512                 health_poll_exit();
 513                 if (ret < 0) {
 514                         /*
 515                          * Restart interrupted system call.
 516                          */
 517                         if (errno == EINTR) {
 518                                 goto restart;
 519                         }
 520                         goto error;
 521                 }
 522                 nb_fd = ret;
 523
 524                 DBG("Relay new viewer connection received");
 525                 for (i = 0; i < nb_fd; i++) {
 526                         health_code_update();
 527
 528                         /* Fetch once the poll data */
 529                         revents = LTTNG_POLL_GETEV(&events, i);
 530                         pollfd = LTTNG_POLL_GETFD(&events, i);
 531
 532                         if (!revents) {
 533                                 /* No activity for this FD (poll implementation). */
 534                                 continue;
 535                         }
 536
 537                         /* Thread quit pipe has been closed. Killing thread. */
 538                         ret = check_thread_quit_pipe(pollfd, revents);
 539                         if (ret) {
 540                                 err = 0;
 541                                 goto exit;
 542                         }
 543
 544                         if (revents & LPOLLIN) {
 545                                 /*
 546                                  * A new connection is requested, therefore a
 547                                  * viewer connection is allocated in this
 548                                  * thread, enqueued to a global queue and
 549                                  * dequeued (and freed) in the worker thread.
 550                                  */
 551                                 int val = 1;
 552                                 struct relay_connection *new_conn;
 553                                 struct lttcomm_sock *newsock;
 554
 555                                 newsock = live_control_sock->ops->accept(live_control_sock);
 556                                 if (!newsock) {
 557                                         PERROR("accepting control sock");
 558                                         goto error;
 559                                 }
 560                                 DBG("Relay viewer connection accepted socket %d", newsock->fd);
 561
 562                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR, &val,
 563                                                 sizeof(val));
 564                                 if (ret < 0) {
 565                                         PERROR("setsockopt inet");
 566                                         lttcomm_destroy_sock(newsock);
 567                                         goto error;
 568                                 }
 569                                 new_conn = connection_create(newsock, RELAY_CONNECTION_UNKNOWN);
 570                                 if (!new_conn) {
 571                                         lttcomm_destroy_sock(newsock);
 572                                         goto error;
 573                                 }
 574                                 /* Ownership assumed by the connection. */
 575                                 newsock = NULL;
 576
 577                                 /* Enqueue request for the dispatcher thread. */
 578                                 cds_wfcq_enqueue(&viewer_conn_queue.head, &viewer_conn_queue.tail,
 579                                                  &new_conn->qnode);
 580
 581                                 /*
 582                                  * Wake the dispatch queue futex.
 583                                  * Implicit memory barrier with the
 584                                  * exchange in cds_wfcq_enqueue.
 585                                  */
 586                                 futex_nto1_wake(&viewer_conn_queue.futex);
 587                         } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 588                                 ERR("socket poll error");
 589                                 goto error;
 590                         } else {
 591                                 ERR("Unexpected poll events %u for sock %d", revents, pollfd);
 592                                 goto error;
 593                         }
 594                 }
 595         }
 596
 597 exit:
 598 error:
 599 error_poll_add:
 600 error_testpoint:
 601         lttng_poll_clean(&events);
 602 error_create_poll:
 603         if (live_control_sock->fd >= 0) {
 604                 ret = live_control_sock->ops->close(live_control_sock);
 605                 if (ret) {
 606                         PERROR("close");
 607                 }
 608         }
 609         lttcomm_destroy_sock(live_control_sock);
 610 error_sock_control:
 611         if (err) {
 612                 health_error();
 613                 DBG("Live viewer listener thread exited with error");
 614         }
 615         health_unregister(health_relayd);
 616         DBG("Live viewer listener thread cleanup complete");
 617         if (lttng_relay_stop_threads()) {
 618                 ERR("Error stopping threads");
 619         }
 620         return NULL;
 621 }
 622
 623 /*
 624  * This thread manages the dispatching of the requests to worker threads
 625  */
 626 static
 627 void *thread_dispatcher(void *data)
 628 {
 629         int err = -1;
 630         ssize_t ret;
 631         struct cds_wfcq_node *node;
 632         struct relay_connection *conn = NULL;
 633
 634         DBG("[thread] Live viewer relay dispatcher started");
 635
 636         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 637
 638         if (testpoint(relayd_thread_live_dispatcher)) {
 639                 goto error_testpoint;
 640         }
 641
 642         health_code_update();
 643
 644         while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 645                 health_code_update();
 646
 647                 /* Atomically prepare the queue futex */
 648                 futex_nto1_prepare(&viewer_conn_queue.futex);
 649
 650                 do {
 651                         health_code_update();
 652
 653                         /* Dequeue commands */
 654                         node = cds_wfcq_dequeue_blocking(&viewer_conn_queue.head,
 655                                                          &viewer_conn_queue.tail);
 656                         if (node == NULL) {
 657                                 DBG("Woken up but nothing in the live-viewer "
 658                                                 "relay command queue");
 659                                 /* Continue thread execution */
 660                                 break;
 661                         }
 662                         conn = caa_container_of(node, struct relay_connection, qnode);
 663                         DBG("Dispatching viewer request waiting on sock %d",
 664                                         conn->sock->fd);
 665
 666                         /*
 667                          * Inform worker thread of the new request. This
 668                          * call is blocking so we can be assured that
 669                          * the data will be read at some point in time
 670                          * or wait to the end of the world :)
 671                          */
 672                         ret = lttng_write(live_conn_pipe[1], &conn, sizeof(conn));
 673                         if (ret < 0) {
 674                                 PERROR("write conn pipe");
 675                                 connection_put(conn);
 676                                 goto error;
 677                         }
 678                 } while (node != NULL);
 679
 680                 /* Futex wait on queue. Blocking call on futex() */
 681                 health_poll_entry();
 682                 futex_nto1_wait(&viewer_conn_queue.futex);
 683                 health_poll_exit();
 684         }
 685
 686         /* Normal exit, no error */
 687         err = 0;
 688
 689 error:
 690 error_testpoint:
 691         if (err) {
 692                 health_error();
 693                 ERR("Health error occurred in %s", __func__);
 694         }
 695         health_unregister(health_relayd);
 696         DBG("Live viewer dispatch thread dying");
 697         if (lttng_relay_stop_threads()) {
 698                 ERR("Error stopping threads");
 699         }
 700         return NULL;
 701 }
 702
 703 /*
 704  * Establish connection with the viewer and check the versions.
 705  *
 706  * Return 0 on success or else negative value.
 707  */
 708 static
 709 int viewer_connect(struct relay_connection *conn)
 710 {
 711         int ret;
 712         struct lttng_viewer_connect reply, msg;
 713
 714         conn->version_check_done = 1;
 715
 716         health_code_update();
 717
 718         DBG("Viewer is establishing a connection to the relayd.");
 719
 720         ret = recv_request(conn->sock, &msg, sizeof(msg));
 721         if (ret < 0) {
 722                 goto end;
 723         }
 724
 725         health_code_update();
 726
 727         memset(&reply, 0, sizeof(reply));
 728         reply.major = RELAYD_VERSION_COMM_MAJOR;
 729         reply.minor = RELAYD_VERSION_COMM_MINOR;
 730
 731         /* Major versions must be the same */
 732         if (reply.major != be32toh(msg.major)) {
 733                 DBG("Incompatible major versions ([relayd] %u vs [client] %u)",
 734                                 reply.major, be32toh(msg.major));
 735                 ret = -1;
 736                 goto end;
 737         }
 738
 739         conn->major = reply.major;
 740         /* We adapt to the lowest compatible version */
 741         if (reply.minor <= be32toh(msg.minor)) {
 742                 conn->minor = reply.minor;
 743         } else {
 744                 conn->minor = be32toh(msg.minor);
 745         }
 746
 747         if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_COMMAND) {
 748                 conn->type = RELAY_VIEWER_COMMAND;
 749         } else if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_NOTIFICATION) {
 750                 conn->type = RELAY_VIEWER_NOTIFICATION;
 751         } else {
 752                 ERR("Unknown connection type : %u", be32toh(msg.type));
 753                 ret = -1;
 754                 goto end;
 755         }
 756
 757         reply.major = htobe32(reply.major);
 758         reply.minor = htobe32(reply.minor);
 759         if (conn->type == RELAY_VIEWER_COMMAND) {
 760                 /*
 761                  * Increment outside of htobe64 macro, because the argument can
 762                  * be used more than once within the macro, and thus the
 763                  * operation may be undefined.
 764                  */
 765                 pthread_mutex_lock(&last_relay_viewer_session_id_lock);
 766                 last_relay_viewer_session_id++;
 767                 pthread_mutex_unlock(&last_relay_viewer_session_id_lock);
 768                 reply.viewer_session_id = htobe64(last_relay_viewer_session_id);
 769         }
 770
 771         health_code_update();
 772
 773         ret = send_response(conn->sock, &reply, sizeof(reply));
 774         if (ret < 0) {
 775                 goto end;
 776         }
 777
 778         health_code_update();
 779
 780         DBG("Version check done using protocol %u.%u", conn->major, conn->minor);
 781         ret = 0;
 782
 783 end:
 784         return ret;
 785 }
 786
 787 /*
 788  * Send the viewer the list of current sessions.
 789  * We need to create a copy of the hash table content because otherwise
 790  * we cannot assume the number of entries stays the same between getting
 791  * the number of HT elements and iteration over the HT.
 792  *
 793  * Return 0 on success or else a negative value.
 794  */
 795 static
 796 int viewer_list_sessions(struct relay_connection *conn)
 797 {
 798         int ret;
 799         struct lttng_viewer_list_sessions session_list;
 800         struct lttng_ht_iter iter;
 801         struct relay_session *session;
 802         struct lttng_viewer_session *send_session_buf = NULL;
 803         uint32_t buf_count = SESSION_BUF_DEFAULT_COUNT;
 804         uint32_t count = 0;
 805
 806         DBG("List sessions received");
 807
 808         send_session_buf = zmalloc(SESSION_BUF_DEFAULT_COUNT * sizeof(*send_session_buf));
 809         if (!send_session_buf) {
 810                 return -1;
 811         }
 812
 813         rcu_read_lock();
 814         cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
 815                         session_n.node) {
 816                 struct lttng_viewer_session *send_session;
 817
 818                 health_code_update();
 819
 820                 if (count >= buf_count) {
 821                         struct lttng_viewer_session *newbuf;
 822                         uint32_t new_buf_count = buf_count << 1;
 823
 824                         newbuf = realloc(send_session_buf,
 825                                 new_buf_count * sizeof(*send_session_buf));
 826                         if (!newbuf) {
 827                                 ret = -1;
 828                                 rcu_read_unlock();
 829                                 goto end_free;
 830                         }
 831                         send_session_buf = newbuf;
 832                         buf_count = new_buf_count;
 833                 }
 834                 send_session = &send_session_buf[count];
 835                 strncpy(send_session->session_name, session->session_name,
 836                                 sizeof(send_session->session_name));
 837                 strncpy(send_session->hostname, session->hostname,
 838                                 sizeof(send_session->hostname));
 839                 send_session->id = htobe64(session->id);
 840                 send_session->live_timer = htobe32(session->live_timer);
 841                 if (session->viewer_attached) {
 842                         send_session->clients = htobe32(1);
 843                 } else {
 844                         send_session->clients = htobe32(0);
 845                 }
 846                 send_session->streams = htobe32(session->stream_count);
 847                 count++;
 848         }
 849         rcu_read_unlock();
 850
 851         session_list.sessions_count = htobe32(count);
 852
 853         health_code_update();
 854
 855         ret = send_response(conn->sock, &session_list, sizeof(session_list));
 856         if (ret < 0) {
 857                 goto end_free;
 858         }
 859
 860         health_code_update();
 861
 862         ret = send_response(conn->sock, send_session_buf,
 863                         count * sizeof(*send_session_buf));
 864         if (ret < 0) {
 865                 goto end_free;
 866         }
 867         health_code_update();
 868
 869         ret = 0;
 870 end_free:
 871         free(send_session_buf);
 872         return ret;
 873 }
 874
 875 /*
 876  * Send the viewer the list of current streams.
 877  */
 878 static
 879 int viewer_get_new_streams(struct relay_connection *conn)
 880 {
 881         int ret, send_streams = 0;
 882         uint32_t nb_created = 0, nb_unsent = 0, nb_streams = 0, nb_total = 0;
 883         struct lttng_viewer_new_streams_request request;
 884         struct lttng_viewer_new_streams_response response;
 885         struct relay_session *session;
 886         uint64_t session_id;
 887         bool closed = false;
 888
 889         assert(conn);
 890
 891         DBG("Get new streams received");
 892
 893         health_code_update();
 894
 895         /* Receive the request from the connected client. */
 896         ret = recv_request(conn->sock, &request, sizeof(request));
 897         if (ret < 0) {
 898                 goto error;
 899         }
 900         session_id = be64toh(request.session_id);
 901
 902         health_code_update();
 903
 904         memset(&response, 0, sizeof(response));
 905
 906         session = session_get_by_id(session_id);
 907         if (!session) {
 908                 DBG("Relay session %" PRIu64 " not found", session_id);
 909                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 910                 goto send_reply;
 911         }
 912
 913         if (!viewer_session_is_attached(conn->viewer_session, session)) {
 914                 send_streams = 0;
 915                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 916                 goto send_reply;
 917         }
 918
 919         send_streams = 1;
 920         response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 921
 922         ret = make_viewer_streams(session, LTTNG_VIEWER_SEEK_LAST, &nb_total, &nb_unsent,
 923                         &nb_created, &closed);
 924         if (ret < 0) {
 925                 goto end_put_session;
 926         }
 927         /* Only send back the newly created streams with the unsent ones. */
 928         nb_streams = nb_created + nb_unsent;
 929         response.streams_count = htobe32(nb_streams);
 930
 931         /*
 932          * If the session is closed, HUP when there are no more streams
 933          * with data.
 934          */
 935         if (closed && nb_total == 0) {
 936                 send_streams = 0;
 937                 response.streams_count = 0;
 938                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
 939                 goto send_reply;
 940         }
 941
 942 send_reply:
 943         health_code_update();
 944         ret = send_response(conn->sock, &response, sizeof(response));
 945         if (ret < 0) {
 946                 goto end_put_session;
 947         }
 948         health_code_update();
 949
 950         /*
 951          * Unknown or empty session, just return gracefully, the viewer
 952          * knows what is happening.
 953          */
 954         if (!send_streams || !nb_streams) {
 955                 ret = 0;
 956                 goto end_put_session;
 957         }
 958
 959         /*
 960          * Send stream and *DON'T* ignore the sent flag so every viewer
 961          * streams that were not sent from that point will be sent to
 962          * the viewer.
 963          */
 964         ret = send_viewer_streams(conn->sock, session, 0);
 965         if (ret < 0) {
 966                 goto end_put_session;
 967         }
 968
 969 end_put_session:
 970         if (session) {
 971                 session_put(session);
 972         }
 973 error:
 974         return ret;
 975 }
 976
 977 /*
 978  * Send the viewer the list of current sessions.
 979  */
 980 static
 981 int viewer_attach_session(struct relay_connection *conn)
 982 {
 983         int send_streams = 0;
 984         ssize_t ret;
 985         uint32_t nb_streams = 0;
 986         enum lttng_viewer_seek seek_type;
 987         struct lttng_viewer_attach_session_request request;
 988         struct lttng_viewer_attach_session_response response;
 989         struct relay_session *session = NULL;
 990         bool closed = false;
 991
 992         assert(conn);
 993
 994         health_code_update();
 995
 996         /* Receive the request from the connected client. */
 997         ret = recv_request(conn->sock, &request, sizeof(request));
 998         if (ret < 0) {
 999                 goto error;
1000         }
1001
1002         health_code_update();
1003
1004         memset(&response, 0, sizeof(response));
1005
1006         if (!conn->viewer_session) {
1007                 DBG("Client trying to attach before creating a live viewer session");
1008                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NO_SESSION);
1009                 goto send_reply;
1010         }
1011
1012         session = session_get_by_id(be64toh(request.session_id));
1013         if (!session) {
1014                 DBG("Relay session %" PRIu64 " not found",
1015                                 be64toh(request.session_id));
1016                 response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
1017                 goto send_reply;
1018         }
1019         DBG("Attach session ID %" PRIu64 " received",
1020                 be64toh(request.session_id));
1021
1022         if (session->live_timer == 0) {
1023                 DBG("Not live session");
1024                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NOT_LIVE);
1025                 goto send_reply;
1026         }
1027
1028         send_streams = 1;
1029         ret = viewer_session_attach(conn->viewer_session, session);
1030         if (ret) {
1031                 DBG("Already a viewer attached");
1032                 response.status = htobe32(LTTNG_VIEWER_ATTACH_ALREADY);
1033                 goto send_reply;
1034         }
1035
1036         switch (be32toh(request.seek)) {
1037         case LTTNG_VIEWER_SEEK_BEGINNING:
1038         case LTTNG_VIEWER_SEEK_LAST:
1039                 response.status = htobe32(LTTNG_VIEWER_ATTACH_OK);
1040                 seek_type = be32toh(request.seek);
1041                 break;
1042         default:
1043                 ERR("Wrong seek parameter");
1044                 response.status = htobe32(LTTNG_VIEWER_ATTACH_SEEK_ERR);
1045                 send_streams = 0;
1046                 goto send_reply;
1047         }
1048
1049         ret = make_viewer_streams(session, seek_type, &nb_streams, NULL,
1050                         NULL, &closed);
1051         if (ret < 0) {
1052                 goto end_put_session;
1053         }
1054         response.streams_count = htobe32(nb_streams);
1055
1056         /*
1057          * If the session is closed when the viewer is attaching, it
1058          * means some of the streams may have been concurrently removed,
1059          * so we don't allow the viewer to attach, even if there are
1060          * streams available.
1061          */
1062         if (closed) {
1063                 send_streams = 0;
1064                 response.streams_count = 0;
1065                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
1066                 goto send_reply;
1067         }
1068
1069 send_reply:
1070         health_code_update();
1071         ret = send_response(conn->sock, &response, sizeof(response));
1072         if (ret < 0) {
1073                 goto end_put_session;
1074         }
1075         health_code_update();
1076
1077         /*
1078          * Unknown or empty session, just return gracefully, the viewer
1079          * knows what is happening.
1080          */
1081         if (!send_streams || !nb_streams) {
1082                 ret = 0;
1083                 goto end_put_session;
1084         }
1085
1086         /* Send stream and ignore the sent flag. */
1087         ret = send_viewer_streams(conn->sock, session, 1);
1088         if (ret < 0) {
1089                 goto end_put_session;
1090         }
1091
1092 end_put_session:
1093         if (session) {
1094                 session_put(session);
1095         }
1096 error:
1097         return ret;
1098 }
1099
1100 /*
1101  * Open the index file if needed for the given vstream.
1102  *
1103  * If an index file is successfully opened, the vstream index_fd set with
1104  * it.
1105  *
1106  * Return 0 on success, a negative value on error (-ENOENT if not ready yet).
1107  *
1108  * Called with rstream lock held.
1109  */
1110 static int try_open_index(struct relay_viewer_stream *vstream,
1111                 struct relay_stream *rstream)
1112 {
1113         int ret = 0;
1114
1115         if (vstream->index_fd) {
1116                 goto end;
1117         }
1118
1119         /*
1120          * First time, we open the index file and at least one index is ready.
1121          */
1122         if (rstream->index_received_seqcount == 0) {
1123                 ret = -ENOENT;
1124                 goto end;
1125         }
1126         ret = index_open(vstream->path_name, vstream->channel_name,
1127                         vstream->stream->tracefile_count,
1128                         vstream->current_tracefile_id);
1129         if (ret >= 0) {
1130                 vstream->index_fd = stream_fd_create(ret);
1131                 if (!vstream->index_fd) {
1132                         if (close(ret)) {
1133                                 PERROR("close");
1134                         }
1135                         ret = -1;
1136                 } else {
1137                         ret = 0;
1138                 }
1139                 goto end;
1140         }
1141
1142 end:
1143         return ret;
1144 }
1145
1146 /*
1147  * Check the status of the index for the given stream. This function
1148  * updates the index structure if needed and can put (close) the vstream
1149  * in the HUP situation.
1150  *
1151  * Return 0 means that we can proceed with the index. A value of 1 means
1152  * that the index has been updated and is ready to be sent to the
1153  * client. A negative value indicates an error that can't be handled.
1154  *
1155  * Called with rstream lock held.
1156  */
1157 static int check_index_status(struct relay_viewer_stream *vstream,
1158                 struct relay_stream *rstream, struct ctf_trace *trace,
1159                 struct lttng_viewer_index *index)
1160 {
1161         int ret;
1162
1163         if (trace->session->connection_closed
1164                         && rstream->index_received_seqcount
1165                                 == vstream->index_sent_seqcount) {
1166                 /* Last index sent and session connection is closed. */
1167                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1168                 goto hup;
1169         } else if (rstream->beacon_ts_end != -1ULL &&
1170                         rstream->index_received_seqcount
1171                                 == vstream->index_sent_seqcount) {
1172                 /*
1173                  * We've received a synchronization beacon and the last index
1174                  * available has been sent, the index for now is inactive.
1175                  *
1176                  * In this case, we have received a beacon which allows us to
1177                  * inform the client of a time interval during which we can
1178                  * guarantee that there are no events to read (and never will
1179                  * be).
1180                  */
1181                 index->status = htobe32(LTTNG_VIEWER_INDEX_INACTIVE);
1182                 index->timestamp_end = htobe64(rstream->beacon_ts_end);
1183                 index->stream_id = htobe64(rstream->ctf_stream_id);
1184                 goto index_ready;
1185         } else if (rstream->index_received_seqcount
1186                         == vstream->index_sent_seqcount) {
1187                 /*
1188                  * This checks whether received == sent seqcount. In
1189                  * this case, we have not received a beacon. Therefore,
1190                  * we can only ask the client to retry later.
1191                  */
1192                 index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1193                 goto index_ready;
1194         } else if (!tracefile_array_seq_in_file(rstream->tfa,
1195                         vstream->current_tracefile_id,
1196                         vstream->index_sent_seqcount)) {
1197                 /*
1198                  * The next index we want to send cannot be read either
1199                  * because we need to perform a rotation, or due to
1200                  * the producer having overwritten its trace file.
1201                  */
1202                 DBG("Viewer stream %" PRIu64 " rotation",
1203                                 vstream->stream->stream_handle);
1204                 ret = viewer_stream_rotate(vstream);
1205                 if (ret < 0) {
1206                         goto end;
1207                 } else if (ret == 1) {
1208                         /* EOF across entire stream. */
1209                         index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1210                         goto hup;
1211                 }
1212                 /*
1213                  * If we have been pushed due to overwrite, it
1214                  * necessarily means there is data that can be read in
1215                  * the stream. If we rotated because we reached the end
1216                  * of a tracefile, it means the following tracefile
1217                  * needs to contain at least one index, else we would
1218                  * have already returned LTTNG_VIEWER_INDEX_RETRY to the
1219                  * viewer. The updated index_sent_seqcount needs to
1220                  * point to a readable index entry now.
1221                  *
1222                  * In the case where we "rotate" on a single file, we
1223                  * can end up in a case where the requested index is
1224                  * still unavailable.
1225                  */
1226                 if (rstream->tracefile_count == 1 &&
1227                                 !tracefile_array_seq_in_file(
1228                                         rstream->tfa,
1229                                         vstream->current_tracefile_id,
1230                                         vstream->index_sent_seqcount)) {
1231                         index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1232                         goto index_ready;
1233                 }
1234                 assert(tracefile_array_seq_in_file(rstream->tfa,
1235                                 vstream->current_tracefile_id,
1236                                 vstream->index_sent_seqcount));
1237         }
1238         /* ret == 0 means successful so we continue. */
1239         ret = 0;
1240 end:
1241         return ret;
1242
1243 hup:
1244         viewer_stream_put(vstream);
1245 index_ready:
1246         return 1;
1247 }
1248
1249 /*
1250  * Send the next index for a stream.
1251  *
1252  * Return 0 on success or else a negative value.
1253  */
1254 static
1255 int viewer_get_next_index(struct relay_connection *conn)
1256 {
1257         int ret;
1258         ssize_t read_ret;
1259         struct lttng_viewer_get_next_index request_index;
1260         struct lttng_viewer_index viewer_index;
1261         struct ctf_packet_index packet_index;
1262         struct relay_viewer_stream *vstream = NULL;
1263         struct relay_stream *rstream = NULL;
1264         struct ctf_trace *ctf_trace = NULL;
1265         struct relay_viewer_stream *metadata_viewer_stream = NULL;
1266
1267         assert(conn);
1268
1269         DBG("Viewer get next index");
1270
1271         memset(&viewer_index, 0, sizeof(viewer_index));
1272         health_code_update();
1273
1274         ret = recv_request(conn->sock, &request_index, sizeof(request_index));
1275         if (ret < 0) {
1276                 goto end;
1277         }
1278         health_code_update();
1279
1280         vstream = viewer_stream_get_by_id(be64toh(request_index.stream_id));
1281         if (!vstream) {
1282                 DBG("Client requested index of unknown stream id %" PRIu64,
1283                                 be64toh(request_index.stream_id));
1284                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1285                 goto send_reply;
1286         }
1287
1288         /* Use back. ref. Protected by refcounts. */
1289         rstream = vstream->stream;
1290         ctf_trace = rstream->trace;
1291
1292         /* metadata_viewer_stream may be NULL. */
1293         metadata_viewer_stream =
1294                         ctf_trace_get_viewer_metadata_stream(ctf_trace);
1295
1296         pthread_mutex_lock(&rstream->lock);
1297
1298         /*
1299          * The viewer should not ask for index on metadata stream.
1300          */
1301         if (rstream->is_metadata) {
1302                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1303                 goto send_reply;
1304         }
1305
1306         /* Try to open an index if one is needed for that stream. */
1307         ret = try_open_index(vstream, rstream);
1308         if (ret < 0) {
1309                 if (ret == -ENOENT) {
1310                         /*
1311                          * The index is created only when the first data
1312                          * packet arrives, it might not be ready at the
1313                          * beginning of the session
1314                          */
1315                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1316                 } else {
1317                         /* Unhandled error. */
1318                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1319                 }
1320                 goto send_reply;
1321         }
1322
1323         ret = check_index_status(vstream, rstream, ctf_trace, &viewer_index);
1324         if (ret < 0) {
1325                 goto error_put;
1326         } else if (ret == 1) {
1327                 /*
1328                  * We have no index to send and check_index_status has populated
1329                  * viewer_index's status.
1330                  */
1331                 goto send_reply;
1332         }
1333         /* At this point, ret is 0 thus we will be able to read the index. */
1334         assert(!ret);
1335
1336         /*
1337          * vstream->stream_fd may be NULL if it has been closed by
1338          * tracefile rotation, or if we are at the beginning of the
1339          * stream. We open the data stream file here to protect against
1340          * overwrite caused by tracefile rotation (in association with
1341          * unlink performed before overwrite).
1342          */
1343         if (!vstream->stream_fd) {
1344                 char fullpath[PATH_MAX];
1345
1346                 if (vstream->stream->tracefile_count > 0) {
1347                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64,
1348                                         vstream->path_name,
1349                                         vstream->channel_name,
1350                                         vstream->current_tracefile_id);
1351                 } else {
1352                         ret = snprintf(fullpath, PATH_MAX, "%s/%s",
1353                                         vstream->path_name,
1354                                         vstream->channel_name);
1355                 }
1356                 if (ret < 0) {
1357                         goto error_put;
1358                 }
1359                 ret = open(fullpath, O_RDONLY);
1360                 if (ret < 0) {
1361                         PERROR("Relay opening trace file");
1362                         goto error_put;
1363                 }
1364                 vstream->stream_fd = stream_fd_create(ret);
1365                 if (!vstream->stream_fd) {
1366                         if (close(ret)) {
1367                                 PERROR("close");
1368                         }
1369                         goto error_put;
1370                 }
1371         }
1372
1373         ret = check_new_streams(conn);
1374         if (ret < 0) {
1375                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1376                 goto send_reply;
1377         } else if (ret == 1) {
1378                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1379         }
1380
1381         read_ret = lttng_read(vstream->index_fd->fd, &packet_index,
1382                         sizeof(packet_index));
1383         if (read_ret < sizeof(packet_index)) {
1384                 ERR("Relay reading index file %d returned %zd",
1385                         vstream->index_fd->fd, read_ret);
1386                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1387                 goto send_reply;
1388         } else {
1389                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_OK);
1390                 vstream->index_sent_seqcount++;
1391         }
1392
1393         /*
1394          * Indexes are stored in big endian, no need to switch before sending.
1395          */
1396         DBG("Sending viewer index for stream %" PRIu64 " offset %" PRIu64,
1397                 rstream->stream_handle,
1398                 be64toh(packet_index.offset));
1399         viewer_index.offset = packet_index.offset;
1400         viewer_index.packet_size = packet_index.packet_size;
1401         viewer_index.content_size = packet_index.content_size;
1402         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1403         viewer_index.timestamp_end = packet_index.timestamp_end;
1404         viewer_index.events_discarded = packet_index.events_discarded;
1405         viewer_index.stream_id = packet_index.stream_id;
1406
1407 send_reply:
1408         if (rstream) {
1409                 pthread_mutex_unlock(&rstream->lock);
1410         }
1411
1412         if (metadata_viewer_stream) {
1413                 pthread_mutex_lock(&metadata_viewer_stream->stream->lock);
1414                 DBG("get next index metadata check: recv %" PRIu64
1415                                 " sent %" PRIu64,
1416                         metadata_viewer_stream->stream->metadata_received,
1417                         metadata_viewer_stream->metadata_sent);
1418                 if (!metadata_viewer_stream->stream->metadata_received ||
1419                                 metadata_viewer_stream->stream->metadata_received >
1420                                         metadata_viewer_stream->metadata_sent) {
1421                         viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1422                 }
1423                 pthread_mutex_unlock(&metadata_viewer_stream->stream->lock);
1424         }
1425
1426         viewer_index.flags = htobe32(viewer_index.flags);
1427         health_code_update();
1428
1429         ret = send_response(conn->sock, &viewer_index, sizeof(viewer_index));
1430         if (ret < 0) {
1431                 goto end;
1432         }
1433         health_code_update();
1434
1435         if (vstream) {
1436                 DBG("Index %" PRIu64 " for stream %" PRIu64 " sent",
1437                                 vstream->index_sent_seqcount,
1438                                 vstream->stream->stream_handle);
1439         }
1440 end:
1441         if (metadata_viewer_stream) {
1442                 viewer_stream_put(metadata_viewer_stream);
1443         }
1444         if (vstream) {
1445                 viewer_stream_put(vstream);
1446         }
1447         return ret;
1448
1449 error_put:
1450         pthread_mutex_unlock(&rstream->lock);
1451         if (metadata_viewer_stream) {
1452                 viewer_stream_put(metadata_viewer_stream);
1453         }
1454         viewer_stream_put(vstream);
1455         return ret;
1456 }
1457
1458 /*
1459  * Send the next index for a stream
1460  *
1461  * Return 0 on success or else a negative value.
1462  */
1463 static
1464 int viewer_get_packet(struct relay_connection *conn)
1465 {
1466         int ret, send_data = 0;
1467         char *data = NULL;
1468         uint32_t len = 0;
1469         ssize_t read_len;
1470         struct lttng_viewer_get_packet get_packet_info;
1471         struct lttng_viewer_trace_packet reply;
1472         struct relay_viewer_stream *vstream = NULL;
1473
1474         DBG2("Relay get data packet");
1475
1476         health_code_update();
1477
1478         ret = recv_request(conn->sock, &get_packet_info,
1479                         sizeof(get_packet_info));
1480         if (ret < 0) {
1481                 goto end;
1482         }
1483         health_code_update();
1484
1485         /* From this point on, the error label can be reached. */
1486         memset(&reply, 0, sizeof(reply));
1487
1488         vstream = viewer_stream_get_by_id(be64toh(get_packet_info.stream_id));
1489         if (!vstream) {
1490                 DBG("Client requested packet of unknown stream id %" PRIu64,
1491                                 be64toh(get_packet_info.stream_id));
1492                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1493                 goto send_reply_nolock;
1494         }
1495
1496         pthread_mutex_lock(&vstream->stream->lock);
1497
1498         len = be32toh(get_packet_info.len);
1499         data = zmalloc(len);
1500         if (!data) {
1501                 PERROR("relay data zmalloc");
1502                 goto error;
1503         }
1504
1505         ret = lseek(vstream->stream_fd->fd, be64toh(get_packet_info.offset),
1506                         SEEK_SET);
1507         if (ret < 0) {
1508                 PERROR("lseek fd %d to offset %" PRIu64, vstream->stream_fd->fd,
1509                         be64toh(get_packet_info.offset));
1510                 goto error;
1511         }
1512         read_len = lttng_read(vstream->stream_fd->fd, data, len);
1513         if (read_len < len) {
1514                 PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1515                                 vstream->stream_fd->fd,
1516                                 be64toh(get_packet_info.offset));
1517                 goto error;
1518         }
1519         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_OK);
1520         reply.len = htobe32(len);
1521         send_data = 1;
1522         goto send_reply;
1523
1524 error:
1525         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1526
1527 send_reply:
1528         if (vstream) {
1529                 pthread_mutex_unlock(&vstream->stream->lock);
1530         }
1531 send_reply_nolock:
1532         reply.flags = htobe32(reply.flags);
1533
1534         health_code_update();
1535
1536         ret = send_response(conn->sock, &reply, sizeof(reply));
1537         if (ret < 0) {
1538                 goto end_free;
1539         }
1540         health_code_update();
1541
1542         if (send_data) {
1543                 health_code_update();
1544                 ret = send_response(conn->sock, data, len);
1545                 if (ret < 0) {
1546                         goto end_free;
1547                 }
1548                 health_code_update();
1549         }
1550
1551         DBG("Sent %u bytes for stream %" PRIu64, len,
1552                         be64toh(get_packet_info.stream_id));
1553
1554 end_free:
1555         free(data);
1556 end:
1557         if (vstream) {
1558                 viewer_stream_put(vstream);
1559         }
1560         return ret;
1561 }
1562
1563 /*
1564  * Send the session's metadata
1565  *
1566  * Return 0 on success else a negative value.
1567  */
1568 static
1569 int viewer_get_metadata(struct relay_connection *conn)
1570 {
1571         int ret = 0;
1572         ssize_t read_len;
1573         uint64_t len = 0;
1574         char *data = NULL;
1575         struct lttng_viewer_get_metadata request;
1576         struct lttng_viewer_metadata_packet reply;
1577         struct relay_viewer_stream *vstream = NULL;
1578
1579         assert(conn);
1580
1581         DBG("Relay get metadata");
1582
1583         health_code_update();
1584
1585         ret = recv_request(conn->sock, &request, sizeof(request));
1586         if (ret < 0) {
1587                 goto end;
1588         }
1589         health_code_update();
1590
1591         memset(&reply, 0, sizeof(reply));
1592
1593         vstream = viewer_stream_get_by_id(be64toh(request.stream_id));
1594         if (!vstream) {
1595                 /*
1596                  * The metadata stream can be closed by a CLOSE command
1597                  * just before we attach. It can also be closed by
1598                  * per-pid tracing during tracing. Therefore, it is
1599                  * possible that we cannot find this viewer stream.
1600                  * Reply back to the client with an error if we cannot
1601                  * find it.
1602                  */
1603                 DBG("Client requested metadata of unknown stream id %" PRIu64,
1604                                 be64toh(request.stream_id));
1605                 reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1606                 goto send_reply;
1607         }
1608         pthread_mutex_lock(&vstream->stream->lock);
1609         if (!vstream->stream->is_metadata) {
1610                 ERR("Invalid metadata stream");
1611                 goto error;
1612         }
1613
1614         assert(vstream->metadata_sent <= vstream->stream->metadata_received);
1615
1616         len = vstream->stream->metadata_received - vstream->metadata_sent;
1617         if (len == 0) {
1618                 reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
1619                 goto send_reply;
1620         }
1621
1622         /* first time, we open the metadata file */
1623         if (!vstream->stream_fd) {
1624                 char fullpath[PATH_MAX];
1625
1626                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", vstream->path_name,
1627                                 vstream->channel_name);
1628                 if (ret < 0) {
1629                         goto error;
1630                 }
1631                 ret = open(fullpath, O_RDONLY);
1632                 if (ret < 0) {
1633                         PERROR("Relay opening metadata file");
1634                         goto error;
1635                 }
1636                 vstream->stream_fd = stream_fd_create(ret);
1637                 if (!vstream->stream_fd) {
1638                         if (close(ret)) {
1639                                 PERROR("close");
1640                         }
1641                         goto error;
1642                 }
1643         }
1644
1645         reply.len = htobe64(len);
1646         data = zmalloc(len);
1647         if (!data) {
1648                 PERROR("viewer metadata zmalloc");
1649                 goto error;
1650         }
1651
1652         read_len = lttng_read(vstream->stream_fd->fd, data, len);
1653         if (read_len < len) {
1654                 PERROR("Relay reading metadata file");
1655                 goto error;
1656         }
1657         vstream->metadata_sent += read_len;
1658         if (vstream->metadata_sent == vstream->stream->metadata_received
1659                         && vstream->stream->closed) {
1660                 /* Release ownership for the viewer metadata stream. */
1661                 viewer_stream_put(vstream);
1662         }
1663
1664         reply.status = htobe32(LTTNG_VIEWER_METADATA_OK);
1665
1666         goto send_reply;
1667
1668 error:
1669         reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1670
1671 send_reply:
1672         health_code_update();
1673         if (vstream) {
1674                 pthread_mutex_unlock(&vstream->stream->lock);
1675         }
1676         ret = send_response(conn->sock, &reply, sizeof(reply));
1677         if (ret < 0) {
1678                 goto end_free;
1679         }
1680         health_code_update();
1681
1682         if (len > 0) {
1683                 ret = send_response(conn->sock, data, len);
1684                 if (ret < 0) {
1685                         goto end_free;
1686                 }
1687         }
1688
1689         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1690                         be64toh(request.stream_id));
1691
1692         DBG("Metadata sent");
1693
1694 end_free:
1695         free(data);
1696 end:
1697         if (vstream) {
1698                 viewer_stream_put(vstream);
1699         }
1700         return ret;
1701 }
1702
1703 /*
1704  * Create a viewer session.
1705  *
1706  * Return 0 on success or else a negative value.
1707  */
1708 static
1709 int viewer_create_session(struct relay_connection *conn)
1710 {
1711         int ret;
1712         struct lttng_viewer_create_session_response resp;
1713
1714         DBG("Viewer create session received");
1715
1716         memset(&resp, 0, sizeof(resp));
1717         resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_OK);
1718         conn->viewer_session = viewer_session_create();
1719         if (!conn->viewer_session) {
1720                 ERR("Allocation viewer session");
1721                 resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_ERR);
1722                 goto send_reply;
1723         }
1724
1725 send_reply:
1726         health_code_update();
1727         ret = send_response(conn->sock, &resp, sizeof(resp));
1728         if (ret < 0) {
1729                 goto end;
1730         }
1731         health_code_update();
1732         ret = 0;
1733
1734 end:
1735         return ret;
1736 }
1737
1738
1739 /*
1740  * live_relay_unknown_command: send -1 if received unknown command
1741  */
1742 static
1743 void live_relay_unknown_command(struct relay_connection *conn)
1744 {
1745         struct lttcomm_relayd_generic_reply reply;
1746
1747         memset(&reply, 0, sizeof(reply));
1748         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1749         (void) send_response(conn->sock, &reply, sizeof(reply));
1750 }
1751
1752 /*
1753  * Process the commands received on the control socket
1754  */
1755 static
1756 int process_control(struct lttng_viewer_cmd *recv_hdr,
1757                 struct relay_connection *conn)
1758 {
1759         int ret = 0;
1760         uint32_t msg_value;
1761
1762         msg_value = be32toh(recv_hdr->cmd);
1763
1764         /*
1765          * Make sure we've done the version check before any command other then a
1766          * new client connection.
1767          */
1768         if (msg_value != LTTNG_VIEWER_CONNECT && !conn->version_check_done) {
1769                 ERR("Viewer conn value %" PRIu32 " before version check", msg_value);
1770                 ret = -1;
1771                 goto end;
1772         }
1773
1774         switch (msg_value) {
1775         case LTTNG_VIEWER_CONNECT:
1776                 ret = viewer_connect(conn);
1777                 break;
1778         case LTTNG_VIEWER_LIST_SESSIONS:
1779                 ret = viewer_list_sessions(conn);
1780                 break;
1781         case LTTNG_VIEWER_ATTACH_SESSION:
1782                 ret = viewer_attach_session(conn);
1783                 break;
1784         case LTTNG_VIEWER_GET_NEXT_INDEX:
1785                 ret = viewer_get_next_index(conn);
1786                 break;
1787         case LTTNG_VIEWER_GET_PACKET:
1788                 ret = viewer_get_packet(conn);
1789                 break;
1790         case LTTNG_VIEWER_GET_METADATA:
1791                 ret = viewer_get_metadata(conn);
1792                 break;
1793         case LTTNG_VIEWER_GET_NEW_STREAMS:
1794                 ret = viewer_get_new_streams(conn);
1795                 break;
1796         case LTTNG_VIEWER_CREATE_SESSION:
1797                 ret = viewer_create_session(conn);
1798                 break;
1799         default:
1800                 ERR("Received unknown viewer command (%u)",
1801                                 be32toh(recv_hdr->cmd));
1802                 live_relay_unknown_command(conn);
1803                 ret = -1;
1804                 goto end;
1805         }
1806
1807 end:
1808         return ret;
1809 }
1810
1811 static
1812 void cleanup_connection_pollfd(struct lttng_poll_event *events, int pollfd)
1813 {
1814         int ret;
1815
1816         (void) lttng_poll_del(events, pollfd);
1817
1818         ret = close(pollfd);
1819         if (ret < 0) {
1820                 ERR("Closing pollfd %d", pollfd);
1821         }
1822 }
1823
1824 /*
1825  * This thread does the actual work
1826  */
1827 static
1828 void *thread_worker(void *data)
1829 {
1830         int ret, err = -1;
1831         uint32_t nb_fd;
1832         struct lttng_poll_event events;
1833         struct lttng_ht *viewer_connections_ht;
1834         struct lttng_ht_iter iter;
1835         struct lttng_viewer_cmd recv_hdr;
1836         struct relay_connection *destroy_conn;
1837
1838         DBG("[thread] Live viewer relay worker started");
1839
1840         rcu_register_thread();
1841
1842         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1843
1844         if (testpoint(relayd_thread_live_worker)) {
1845                 goto error_testpoint;
1846         }
1847
1848         /* table of connections indexed on socket */
1849         viewer_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1850         if (!viewer_connections_ht) {
1851                 goto viewer_connections_ht_error;
1852         }
1853
1854         ret = create_thread_poll_set(&events, 2);
1855         if (ret < 0) {
1856                 goto error_poll_create;
1857         }
1858
1859         ret = lttng_poll_add(&events, live_conn_pipe[0], LPOLLIN | LPOLLRDHUP);
1860         if (ret < 0) {
1861                 goto error;
1862         }
1863
1864 restart:
1865         while (1) {
1866                 int i;
1867
1868                 health_code_update();
1869
1870                 /* Infinite blocking call, waiting for transmission */
1871                 DBG3("Relayd live viewer worker thread polling...");
1872                 health_poll_entry();
1873                 ret = lttng_poll_wait(&events, -1);
1874                 health_poll_exit();
1875                 if (ret < 0) {
1876                         /*
1877                          * Restart interrupted system call.
1878                          */
1879                         if (errno == EINTR) {
1880                                 goto restart;
1881                         }
1882                         goto error;
1883                 }
1884
1885                 nb_fd = ret;
1886
1887                 /*
1888                  * Process control. The control connection is prioritised so we don't
1889                  * starve it with high throughput tracing data on the data
1890                  * connection.
1891                  */
1892                 for (i = 0; i < nb_fd; i++) {
1893                         /* Fetch once the poll data */
1894                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1895                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1896
1897                         health_code_update();
1898
1899                         if (!revents) {
1900                                 /* No activity for this FD (poll implementation). */
1901                                 continue;
1902                         }
1903
1904                         /* Thread quit pipe has been closed. Killing thread. */
1905                         ret = check_thread_quit_pipe(pollfd, revents);
1906                         if (ret) {
1907                                 err = 0;
1908                                 goto exit;
1909                         }
1910
1911                         /* Inspect the relay conn pipe for new connection. */
1912                         if (pollfd == live_conn_pipe[0]) {
1913                                 if (revents & LPOLLIN) {
1914                                         struct relay_connection *conn;
1915
1916                                         ret = lttng_read(live_conn_pipe[0],
1917                                                         &conn, sizeof(conn));
1918                                         if (ret < 0) {
1919                                                 goto error;
1920                                         }
1921                                         lttng_poll_add(&events, conn->sock->fd,
1922                                                         LPOLLIN | LPOLLRDHUP);
1923                                         connection_ht_add(viewer_connections_ht, conn);
1924                                         DBG("Connection socket %d added to poll", conn->sock->fd);
1925                                 } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1926                                         ERR("Relay live pipe error");
1927                                         goto error;
1928                                 } else {
1929                                         ERR("Unexpected poll events %u for sock %d", revents, pollfd);
1930                                         goto error;
1931                                 }
1932                         } else {
1933                                 /* Connection activity. */
1934                                 struct relay_connection *conn;
1935
1936                                 conn = connection_get_by_sock(viewer_connections_ht, pollfd);
1937                                 if (!conn) {
1938                                         continue;
1939                                 }
1940
1941                                 if (revents & LPOLLIN) {
1942                                         ret = conn->sock->ops->recvmsg(conn->sock, &recv_hdr,
1943                                                         sizeof(recv_hdr), 0);
1944                                         if (ret <= 0) {
1945                                                 /* Connection closed. */
1946                                                 cleanup_connection_pollfd(&events, pollfd);
1947                                                 /* Put "create" ownership reference. */
1948                                                 connection_put(conn);
1949                                                 DBG("Viewer control conn closed with %d", pollfd);
1950                                         } else {
1951                                                 ret = process_control(&recv_hdr, conn);
1952                                                 if (ret < 0) {
1953                                                         /* Clear the session on error. */
1954                                                         cleanup_connection_pollfd(&events, pollfd);
1955                                                         /* Put "create" ownership reference. */
1956                                                         connection_put(conn);
1957                                                         DBG("Viewer connection closed with %d", pollfd);
1958                                                 }
1959                                         }
1960                                 } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1961                                         cleanup_connection_pollfd(&events, pollfd);
1962                                         /* Put "create" ownership reference. */
1963                                         connection_put(conn);
1964                                 } else {
1965                                         ERR("Unexpected poll events %u for sock %d", revents, pollfd);
1966                                         connection_put(conn);
1967                                         goto error;
1968                                 }
1969                                 /* Put local "get_by_sock" reference. */
1970                                 connection_put(conn);
1971                         }
1972                 }
1973         }
1974
1975 exit:
1976 error:
1977         lttng_poll_clean(&events);
1978
1979         /* Cleanup reamaining connection object. */
1980         rcu_read_lock();
1981         cds_lfht_for_each_entry(viewer_connections_ht->ht, &iter.iter,
1982                         destroy_conn,
1983                         sock_n.node) {
1984                 health_code_update();
1985                 connection_put(destroy_conn);
1986         }
1987         rcu_read_unlock();
1988 error_poll_create:
1989         lttng_ht_destroy(viewer_connections_ht);
1990 viewer_connections_ht_error:
1991         /* Close relay conn pipes */
1992         utils_close_pipe(live_conn_pipe);
1993         if (err) {
1994                 DBG("Viewer worker thread exited with error");
1995         }
1996         DBG("Viewer worker thread cleanup complete");
1997 error_testpoint:
1998         if (err) {
1999                 health_error();
2000                 ERR("Health error occurred in %s", __func__);
2001         }
2002         health_unregister(health_relayd);
2003         if (lttng_relay_stop_threads()) {
2004                 ERR("Error stopping threads");
2005         }
2006         rcu_unregister_thread();
2007         return NULL;
2008 }
2009
2010 /*
2011  * Create the relay command pipe to wake thread_manage_apps.
2012  * Closed in cleanup().
2013  */
2014 static int create_conn_pipe(void)
2015 {
2016         return utils_create_pipe_cloexec(live_conn_pipe);
2017 }
2018
2019 int relayd_live_join(void)
2020 {
2021         int ret, retval = 0;
2022         void *status;
2023
2024         ret = pthread_join(live_listener_thread, &status);
2025         if (ret) {
2026                 errno = ret;
2027                 PERROR("pthread_join live listener");
2028                 retval = -1;
2029         }
2030
2031         ret = pthread_join(live_worker_thread, &status);
2032         if (ret) {
2033                 errno = ret;
2034                 PERROR("pthread_join live worker");
2035                 retval = -1;
2036         }
2037
2038         ret = pthread_join(live_dispatcher_thread, &status);
2039         if (ret) {
2040                 errno = ret;
2041                 PERROR("pthread_join live dispatcher");
2042                 retval = -1;
2043         }
2044
2045         cleanup_relayd_live();
2046
2047         return retval;
2048 }
2049
2050 /*
2051  * main
2052  */
2053 int relayd_live_create(struct lttng_uri *uri)
2054 {
2055         int ret = 0, retval = 0;
2056         void *status;
2057         int is_root;
2058
2059         if (!uri) {
2060                 retval = -1;
2061                 goto exit_init_data;
2062         }
2063         live_uri = uri;
2064
2065         /* Check if daemon is UID = 0 */
2066         is_root = !getuid();
2067
2068         if (!is_root) {
2069                 if (live_uri->port < 1024) {
2070                         ERR("Need to be root to use ports < 1024");
2071                         retval = -1;
2072                         goto exit_init_data;
2073                 }
2074         }
2075
2076         /* Setup the thread apps communication pipe. */
2077         if (create_conn_pipe()) {
2078                 retval = -1;
2079                 goto exit_init_data;
2080         }
2081
2082         /* Init relay command queue. */
2083         cds_wfcq_init(&viewer_conn_queue.head, &viewer_conn_queue.tail);
2084
2085         /* Set up max poll set size */
2086         lttng_poll_set_max_size();
2087
2088         /* Setup the dispatcher thread */
2089         ret = pthread_create(&live_dispatcher_thread, NULL,
2090                         thread_dispatcher, (void *) NULL);
2091         if (ret) {
2092                 errno = ret;
2093                 PERROR("pthread_create viewer dispatcher");
2094                 retval = -1;
2095                 goto exit_dispatcher_thread;
2096         }
2097
2098         /* Setup the worker thread */
2099         ret = pthread_create(&live_worker_thread, NULL,
2100                         thread_worker, NULL);
2101         if (ret) {
2102                 errno = ret;
2103                 PERROR("pthread_create viewer worker");
2104                 retval = -1;
2105                 goto exit_worker_thread;
2106         }
2107
2108         /* Setup the listener thread */
2109         ret = pthread_create(&live_listener_thread, NULL,
2110                         thread_listener, (void *) NULL);
2111         if (ret) {
2112                 errno = ret;
2113                 PERROR("pthread_create viewer listener");
2114                 retval = -1;
2115                 goto exit_listener_thread;
2116         }
2117
2118         /*
2119          * All OK, started all threads.
2120          */
2121         return retval;
2122
2123         /*
2124          * Join on the live_listener_thread should anything be added after
2125          * the live_listener thread's creation.
2126          */
2127
2128 exit_listener_thread:
2129
2130         ret = pthread_join(live_worker_thread, &status);
2131         if (ret) {
2132                 errno = ret;
2133                 PERROR("pthread_join live worker");
2134                 retval = -1;
2135         }
2136 exit_worker_thread:
2137
2138         ret = pthread_join(live_dispatcher_thread, &status);
2139         if (ret) {
2140                 errno = ret;
2141                 PERROR("pthread_join live dispatcher");
2142                 retval = -1;
2143         }
2144 exit_dispatcher_thread:
2145
2146 exit_init_data:
2147         cleanup_relayd_live();
2148
2149         return retval;
2150 }