src/bin/lttng-relayd/live.c

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