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                 if (lttng_strncpy(send_stream.path_name, vstream->path_name,
 236                                 sizeof(send_stream.path_name))) {
 237                         pthread_mutex_unlock(&vstream->stream->lock);
 238                         viewer_stream_put(vstream);
 239                         ret = -1;       /* Error. */
 240                         goto end_unlock;
 241                 }
 242                 if (lttng_strncpy(send_stream.channel_name,
 243                                 vstream->channel_name,
 244                                 sizeof(send_stream.channel_name))) {
 245                         pthread_mutex_unlock(&vstream->stream->lock);
 246                         viewer_stream_put(vstream);
 247                         ret = -1;       /* Error. */
 248                         goto end_unlock;
 249                 }
 250
 251                 DBG("Sending stream %" PRIu64 " to viewer",
 252                                 vstream->stream->stream_handle);
 253                 vstream->sent_flag = 1;
 254                 pthread_mutex_unlock(&vstream->stream->lock);
 255
 256                 ret = send_response(sock, &send_stream, sizeof(send_stream));
 257                 viewer_stream_put(vstream);
 258                 if (ret < 0) {
 259                         goto end_unlock;
 260                 }
 261         }
 262
 263         ret = 0;
 264
 265 end_unlock:
 266         rcu_read_unlock();
 267         return ret;
 268 }
 269
 270 /*
 271  * Create every viewer stream possible for the given session with the seek
 272  * type. Three counters *can* be return which are in order the total amount of
 273  * viewer stream of the session, the number of unsent stream and the number of
 274  * stream created. Those counters can be NULL and thus will be ignored.
 275  *
 276  * Return 0 on success or else a negative value.
 277  */
 278 static
 279 int make_viewer_streams(struct relay_session *session,
 280                 enum lttng_viewer_seek seek_t, uint32_t *nb_total, uint32_t *nb_unsent,
 281                 uint32_t *nb_created, bool *closed)
 282 {
 283         int ret;
 284         struct lttng_ht_iter iter;
 285         struct ctf_trace *ctf_trace;
 286
 287         assert(session);
 288
 289         /*
 290          * Hold the session lock to ensure that we see either none or
 291          * all initial streams for a session, but no intermediate state.
 292          */
 293         pthread_mutex_lock(&session->lock);
 294
 295         if (session->connection_closed) {
 296                 *closed = true;
 297         }
 298
 299         /*
 300          * Create viewer streams for relay streams that are ready to be
 301          * used for a the given session id only.
 302          */
 303         rcu_read_lock();
 304         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 305                         node.node) {
 306                 struct relay_stream *stream;
 307
 308                 health_code_update();
 309
 310                 if (!ctf_trace_get(ctf_trace)) {
 311                         continue;
 312                 }
 313
 314                 cds_list_for_each_entry_rcu(stream, &ctf_trace->stream_list, stream_node) {
 315                         struct relay_viewer_stream *vstream;
 316
 317                         if (!stream_get(stream)) {
 318                                 continue;
 319                         }
 320                         /*
 321                          * stream published is protected by the session lock.
 322                          */
 323                         if (!stream->published) {
 324                                 goto next;
 325                         }
 326                         vstream = viewer_stream_get_by_id(stream->stream_handle);
 327                         if (!vstream) {
 328                                 vstream = viewer_stream_create(stream, seek_t);
 329                                 if (!vstream) {
 330                                         ret = -1;
 331                                         ctf_trace_put(ctf_trace);
 332                                         stream_put(stream);
 333                                         goto error_unlock;
 334                                 }
 335
 336                                 if (nb_created) {
 337                                         /* Update number of created stream counter. */
 338                                         (*nb_created)++;
 339                                 }
 340                                 /*
 341                                  * Ensure a self-reference is preserved even
 342                                  * after we have put our local reference.
 343                                  */
 344                                 viewer_stream_get(vstream);
 345                         } else {
 346                                 if (!vstream->sent_flag && nb_unsent) {
 347                                         /* Update number of unsent stream counter. */
 348                                         (*nb_unsent)++;
 349                                 }
 350                         }
 351                         /* Update number of total stream counter. */
 352                         if (nb_total) {
 353                                 if (stream->is_metadata) {
 354                                         if (!stream->closed ||
 355                                                         stream->metadata_received > vstream->metadata_sent) {
 356                                                 (*nb_total)++;
 357                                         }
 358                                 } else {
 359                                         if (!stream->closed ||
 360                                                 !(((int64_t) (stream->prev_seq - stream->last_net_seq_num)) >= 0)) {
 361
 362                                                 (*nb_total)++;
 363                                         }
 364                                 }
 365                         }
 366                         /* Put local reference. */
 367                         viewer_stream_put(vstream);
 368                 next:
 369                         stream_put(stream);
 370                 }
 371                 ctf_trace_put(ctf_trace);
 372         }
 373
 374         ret = 0;
 375
 376 error_unlock:
 377         rcu_read_unlock();
 378         pthread_mutex_unlock(&session->lock);
 379         return ret;
 380 }
 381
 382 int relayd_live_stop(void)
 383 {
 384         /* Stop dispatch thread */
 385         CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
 386         futex_nto1_wake(&viewer_conn_queue.futex);
 387         return 0;
 388 }
 389
 390 /*
 391  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 392  */
 393 static
 394 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 395 {
 396         int ret;
 397
 398         if (events == NULL || size == 0) {
 399                 ret = -1;
 400                 goto error;
 401         }
 402
 403         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 404         if (ret < 0) {
 405                 goto error;
 406         }
 407
 408         /* Add quit pipe */
 409         ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
 410         if (ret < 0) {
 411                 goto error;
 412         }
 413
 414         return 0;
 415
 416 error:
 417         return ret;
 418 }
 419
 420 /*
 421  * Check if the thread quit pipe was triggered.
 422  *
 423  * Return 1 if it was triggered else 0;
 424  */
 425 static
 426 int check_thread_quit_pipe(int fd, uint32_t events)
 427 {
 428         if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
 429                 return 1;
 430         }
 431
 432         return 0;
 433 }
 434
 435 /*
 436  * Create and init socket from uri.
 437  */
 438 static
 439 struct lttcomm_sock *init_socket(struct lttng_uri *uri)
 440 {
 441         int ret;
 442         struct lttcomm_sock *sock = NULL;
 443
 444         sock = lttcomm_alloc_sock_from_uri(uri);
 445         if (sock == NULL) {
 446                 ERR("Allocating socket");
 447                 goto error;
 448         }
 449
 450         ret = lttcomm_create_sock(sock);
 451         if (ret < 0) {
 452                 goto error;
 453         }
 454         DBG("Listening on sock %d for live", sock->fd);
 455
 456         ret = sock->ops->bind(sock);
 457         if (ret < 0) {
 458                 goto error;
 459         }
 460
 461         ret = sock->ops->listen(sock, -1);
 462         if (ret < 0) {
 463                 goto error;
 464
 465         }
 466
 467         return sock;
 468
 469 error:
 470         if (sock) {
 471                 lttcomm_destroy_sock(sock);
 472         }
 473         return NULL;
 474 }
 475
 476 /*
 477  * This thread manages the listening for new connections on the network
 478  */
 479 static
 480 void *thread_listener(void *data)
 481 {
 482         int i, ret, pollfd, err = -1;
 483         uint32_t revents, nb_fd;
 484         struct lttng_poll_event events;
 485         struct lttcomm_sock *live_control_sock;
 486
 487         DBG("[thread] Relay live listener started");
 488
 489         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_LISTENER);
 490
 491         health_code_update();
 492
 493         live_control_sock = init_socket(live_uri);
 494         if (!live_control_sock) {
 495                 goto error_sock_control;
 496         }
 497
 498         /* Pass 2 as size here for the thread quit pipe and control sockets. */
 499         ret = create_thread_poll_set(&events, 2);
 500         if (ret < 0) {
 501                 goto error_create_poll;
 502         }
 503
 504         /* Add the control socket */
 505         ret = lttng_poll_add(&events, live_control_sock->fd, LPOLLIN | LPOLLRDHUP);
 506         if (ret < 0) {
 507                 goto error_poll_add;
 508         }
 509
 510         lttng_relay_notify_ready();
 511
 512         if (testpoint(relayd_thread_live_listener)) {
 513                 goto error_testpoint;
 514         }
 515
 516         while (1) {
 517                 health_code_update();
 518
 519                 DBG("Listener accepting live viewers connections");
 520
 521 restart:
 522                 health_poll_entry();
 523                 ret = lttng_poll_wait(&events, -1);
 524                 health_poll_exit();
 525                 if (ret < 0) {
 526                         /*
 527                          * Restart interrupted system call.
 528                          */
 529                         if (errno == EINTR) {
 530                                 goto restart;
 531                         }
 532                         goto error;
 533                 }
 534                 nb_fd = ret;
 535
 536                 DBG("Relay new viewer connection received");
 537                 for (i = 0; i < nb_fd; i++) {
 538                         health_code_update();
 539
 540                         /* Fetch once the poll data */
 541                         revents = LTTNG_POLL_GETEV(&events, i);
 542                         pollfd = LTTNG_POLL_GETFD(&events, i);
 543
 544                         if (!revents) {
 545                                 /* No activity for this FD (poll implementation). */
 546                                 continue;
 547                         }
 548
 549                         /* Thread quit pipe has been closed. Killing thread. */
 550                         ret = check_thread_quit_pipe(pollfd, revents);
 551                         if (ret) {
 552                                 err = 0;
 553                                 goto exit;
 554                         }
 555
 556                         if (revents & LPOLLIN) {
 557                                 /*
 558                                  * A new connection is requested, therefore a
 559                                  * viewer connection is allocated in this
 560                                  * thread, enqueued to a global queue and
 561                                  * dequeued (and freed) in the worker thread.
 562                                  */
 563                                 int val = 1;
 564                                 struct relay_connection *new_conn;
 565                                 struct lttcomm_sock *newsock;
 566
 567                                 newsock = live_control_sock->ops->accept(live_control_sock);
 568                                 if (!newsock) {
 569                                         PERROR("accepting control sock");
 570                                         goto error;
 571                                 }
 572                                 DBG("Relay viewer connection accepted socket %d", newsock->fd);
 573
 574                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR, &val,
 575                                                 sizeof(val));
 576                                 if (ret < 0) {
 577                                         PERROR("setsockopt inet");
 578                                         lttcomm_destroy_sock(newsock);
 579                                         goto error;
 580                                 }
 581                                 new_conn = connection_create(newsock, RELAY_CONNECTION_UNKNOWN);
 582                                 if (!new_conn) {
 583                                         lttcomm_destroy_sock(newsock);
 584                                         goto error;
 585                                 }
 586                                 /* Ownership assumed by the connection. */
 587                                 newsock = NULL;
 588
 589                                 /* Enqueue request for the dispatcher thread. */
 590                                 cds_wfcq_enqueue(&viewer_conn_queue.head, &viewer_conn_queue.tail,
 591                                                  &new_conn->qnode);
 592
 593                                 /*
 594                                  * Wake the dispatch queue futex.
 595                                  * Implicit memory barrier with the
 596                                  * exchange in cds_wfcq_enqueue.
 597                                  */
 598                                 futex_nto1_wake(&viewer_conn_queue.futex);
 599                         } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 600                                 ERR("socket poll error");
 601                                 goto error;
 602                         } else {
 603                                 ERR("Unexpected poll events %u for sock %d", revents, pollfd);
 604                                 goto error;
 605                         }
 606                 }
 607         }
 608
 609 exit:
 610 error:
 611 error_poll_add:
 612 error_testpoint:
 613         lttng_poll_clean(&events);
 614 error_create_poll:
 615         if (live_control_sock->fd >= 0) {
 616                 ret = live_control_sock->ops->close(live_control_sock);
 617                 if (ret) {
 618                         PERROR("close");
 619                 }
 620         }
 621         lttcomm_destroy_sock(live_control_sock);
 622 error_sock_control:
 623         if (err) {
 624                 health_error();
 625                 DBG("Live viewer listener thread exited with error");
 626         }
 627         health_unregister(health_relayd);
 628         DBG("Live viewer listener thread cleanup complete");
 629         if (lttng_relay_stop_threads()) {
 630                 ERR("Error stopping threads");
 631         }
 632         return NULL;
 633 }
 634
 635 /*
 636  * This thread manages the dispatching of the requests to worker threads
 637  */
 638 static
 639 void *thread_dispatcher(void *data)
 640 {
 641         int err = -1;
 642         ssize_t ret;
 643         struct cds_wfcq_node *node;
 644         struct relay_connection *conn = NULL;
 645
 646         DBG("[thread] Live viewer relay dispatcher started");
 647
 648         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 649
 650         if (testpoint(relayd_thread_live_dispatcher)) {
 651                 goto error_testpoint;
 652         }
 653
 654         health_code_update();
 655
 656         while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 657                 health_code_update();
 658
 659                 /* Atomically prepare the queue futex */
 660                 futex_nto1_prepare(&viewer_conn_queue.futex);
 661
 662                 do {
 663                         health_code_update();
 664
 665                         /* Dequeue commands */
 666                         node = cds_wfcq_dequeue_blocking(&viewer_conn_queue.head,
 667                                                          &viewer_conn_queue.tail);
 668                         if (node == NULL) {
 669                                 DBG("Woken up but nothing in the live-viewer "
 670                                                 "relay command queue");
 671                                 /* Continue thread execution */
 672                                 break;
 673                         }
 674                         conn = caa_container_of(node, struct relay_connection, qnode);
 675                         DBG("Dispatching viewer request waiting on sock %d",
 676                                         conn->sock->fd);
 677
 678                         /*
 679                          * Inform worker thread of the new request. This
 680                          * call is blocking so we can be assured that
 681                          * the data will be read at some point in time
 682                          * or wait to the end of the world :)
 683                          */
 684                         ret = lttng_write(live_conn_pipe[1], &conn, sizeof(conn));
 685                         if (ret < 0) {
 686                                 PERROR("write conn pipe");
 687                                 connection_put(conn);
 688                                 goto error;
 689                         }
 690                 } while (node != NULL);
 691
 692                 /* Futex wait on queue. Blocking call on futex() */
 693                 health_poll_entry();
 694                 futex_nto1_wait(&viewer_conn_queue.futex);
 695                 health_poll_exit();
 696         }
 697
 698         /* Normal exit, no error */
 699         err = 0;
 700
 701 error:
 702 error_testpoint:
 703         if (err) {
 704                 health_error();
 705                 ERR("Health error occurred in %s", __func__);
 706         }
 707         health_unregister(health_relayd);
 708         DBG("Live viewer dispatch thread dying");
 709         if (lttng_relay_stop_threads()) {
 710                 ERR("Error stopping threads");
 711         }
 712         return NULL;
 713 }
 714
 715 /*
 716  * Establish connection with the viewer and check the versions.
 717  *
 718  * Return 0 on success or else negative value.
 719  */
 720 static
 721 int viewer_connect(struct relay_connection *conn)
 722 {
 723         int ret;
 724         struct lttng_viewer_connect reply, msg;
 725
 726         conn->version_check_done = 1;
 727
 728         health_code_update();
 729
 730         DBG("Viewer is establishing a connection to the relayd.");
 731
 732         ret = recv_request(conn->sock, &msg, sizeof(msg));
 733         if (ret < 0) {
 734                 goto end;
 735         }
 736
 737         health_code_update();
 738
 739         memset(&reply, 0, sizeof(reply));
 740         reply.major = RELAYD_VERSION_COMM_MAJOR;
 741         reply.minor = RELAYD_VERSION_COMM_MINOR;
 742
 743         /* Major versions must be the same */
 744         if (reply.major != be32toh(msg.major)) {
 745                 DBG("Incompatible major versions ([relayd] %u vs [client] %u)",
 746                                 reply.major, be32toh(msg.major));
 747                 ret = -1;
 748                 goto end;
 749         }
 750
 751         conn->major = reply.major;
 752         /* We adapt to the lowest compatible version */
 753         if (reply.minor <= be32toh(msg.minor)) {
 754                 conn->minor = reply.minor;
 755         } else {
 756                 conn->minor = be32toh(msg.minor);
 757         }
 758
 759         if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_COMMAND) {
 760                 conn->type = RELAY_VIEWER_COMMAND;
 761         } else if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_NOTIFICATION) {
 762                 conn->type = RELAY_VIEWER_NOTIFICATION;
 763         } else {
 764                 ERR("Unknown connection type : %u", be32toh(msg.type));
 765                 ret = -1;
 766                 goto end;
 767         }
 768
 769         reply.major = htobe32(reply.major);
 770         reply.minor = htobe32(reply.minor);
 771         if (conn->type == RELAY_VIEWER_COMMAND) {
 772                 /*
 773                  * Increment outside of htobe64 macro, because the argument can
 774                  * be used more than once within the macro, and thus the
 775                  * operation may be undefined.
 776                  */
 777                 pthread_mutex_lock(&last_relay_viewer_session_id_lock);
 778                 last_relay_viewer_session_id++;
 779                 pthread_mutex_unlock(&last_relay_viewer_session_id_lock);
 780                 reply.viewer_session_id = htobe64(last_relay_viewer_session_id);
 781         }
 782
 783         health_code_update();
 784
 785         ret = send_response(conn->sock, &reply, sizeof(reply));
 786         if (ret < 0) {
 787                 goto end;
 788         }
 789
 790         health_code_update();
 791
 792         DBG("Version check done using protocol %u.%u", conn->major, conn->minor);
 793         ret = 0;
 794
 795 end:
 796         return ret;
 797 }
 798
 799 /*
 800  * Send the viewer the list of current sessions.
 801  * We need to create a copy of the hash table content because otherwise
 802  * we cannot assume the number of entries stays the same between getting
 803  * the number of HT elements and iteration over the HT.
 804  *
 805  * Return 0 on success or else a negative value.
 806  */
 807 static
 808 int viewer_list_sessions(struct relay_connection *conn)
 809 {
 810         int ret;
 811         struct lttng_viewer_list_sessions session_list;
 812         struct lttng_ht_iter iter;
 813         struct relay_session *session;
 814         struct lttng_viewer_session *send_session_buf = NULL;
 815         uint32_t buf_count = SESSION_BUF_DEFAULT_COUNT;
 816         uint32_t count = 0;
 817
 818         DBG("List sessions received");
 819
 820         send_session_buf = zmalloc(SESSION_BUF_DEFAULT_COUNT * sizeof(*send_session_buf));
 821         if (!send_session_buf) {
 822                 return -1;
 823         }
 824
 825         rcu_read_lock();
 826         cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
 827                         session_n.node) {
 828                 struct lttng_viewer_session *send_session;
 829
 830                 health_code_update();
 831
 832                 if (count >= buf_count) {
 833                         struct lttng_viewer_session *newbuf;
 834                         uint32_t new_buf_count = buf_count << 1;
 835
 836                         newbuf = realloc(send_session_buf,
 837                                 new_buf_count * sizeof(*send_session_buf));
 838                         if (!newbuf) {
 839                                 ret = -1;
 840                                 rcu_read_unlock();
 841                                 goto end_free;
 842                         }
 843                         send_session_buf = newbuf;
 844                         buf_count = new_buf_count;
 845                 }
 846                 send_session = &send_session_buf[count];
 847                 if (lttng_strncpy(send_session->session_name,
 848                                 session->session_name,
 849                                 sizeof(send_session->session_name))) {
 850                         ret = -1;
 851                         rcu_read_unlock();
 852                         goto end_free;
 853                 }
 854                 if (lttng_strncpy(send_session->hostname, session->hostname,
 855                                 sizeof(send_session->hostname))) {
 856                         ret = -1;
 857                         rcu_read_unlock();
 858                         goto end_free;
 859                 }
 860                 send_session->id = htobe64(session->id);
 861                 send_session->live_timer = htobe32(session->live_timer);
 862                 if (session->viewer_attached) {
 863                         send_session->clients = htobe32(1);
 864                 } else {
 865                         send_session->clients = htobe32(0);
 866                 }
 867                 send_session->streams = htobe32(session->stream_count);
 868                 count++;
 869         }
 870         rcu_read_unlock();
 871
 872         session_list.sessions_count = htobe32(count);
 873
 874         health_code_update();
 875
 876         ret = send_response(conn->sock, &session_list, sizeof(session_list));
 877         if (ret < 0) {
 878                 goto end_free;
 879         }
 880
 881         health_code_update();
 882
 883         ret = send_response(conn->sock, send_session_buf,
 884                         count * sizeof(*send_session_buf));
 885         if (ret < 0) {
 886                 goto end_free;
 887         }
 888         health_code_update();
 889
 890         ret = 0;
 891 end_free:
 892         free(send_session_buf);
 893         return ret;
 894 }
 895
 896 /*
 897  * Send the viewer the list of current streams.
 898  */
 899 static
 900 int viewer_get_new_streams(struct relay_connection *conn)
 901 {
 902         int ret, send_streams = 0;
 903         uint32_t nb_created = 0, nb_unsent = 0, nb_streams = 0, nb_total = 0;
 904         struct lttng_viewer_new_streams_request request;
 905         struct lttng_viewer_new_streams_response response;
 906         struct relay_session *session;
 907         uint64_t session_id;
 908         bool closed = false;
 909
 910         assert(conn);
 911
 912         DBG("Get new streams received");
 913
 914         health_code_update();
 915
 916         /* Receive the request from the connected client. */
 917         ret = recv_request(conn->sock, &request, sizeof(request));
 918         if (ret < 0) {
 919                 goto error;
 920         }
 921         session_id = be64toh(request.session_id);
 922
 923         health_code_update();
 924
 925         memset(&response, 0, sizeof(response));
 926
 927         session = session_get_by_id(session_id);
 928         if (!session) {
 929                 DBG("Relay session %" PRIu64 " not found", session_id);
 930                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 931                 goto send_reply;
 932         }
 933
 934         if (!viewer_session_is_attached(conn->viewer_session, session)) {
 935                 send_streams = 0;
 936                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 937                 goto send_reply;
 938         }
 939
 940         send_streams = 1;
 941         response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 942
 943         ret = make_viewer_streams(session, LTTNG_VIEWER_SEEK_LAST, &nb_total, &nb_unsent,
 944                         &nb_created, &closed);
 945         if (ret < 0) {
 946                 goto end_put_session;
 947         }
 948         /* Only send back the newly created streams with the unsent ones. */
 949         nb_streams = nb_created + nb_unsent;
 950         response.streams_count = htobe32(nb_streams);
 951
 952         /*
 953          * If the session is closed, HUP when there are no more streams
 954          * with data.
 955          */
 956         if (closed && nb_total == 0) {
 957                 send_streams = 0;
 958                 response.streams_count = 0;
 959                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
 960                 goto send_reply;
 961         }
 962
 963 send_reply:
 964         health_code_update();
 965         ret = send_response(conn->sock, &response, sizeof(response));
 966         if (ret < 0) {
 967                 goto end_put_session;
 968         }
 969         health_code_update();
 970
 971         /*
 972          * Unknown or empty session, just return gracefully, the viewer
 973          * knows what is happening.
 974          */
 975         if (!send_streams || !nb_streams) {
 976                 ret = 0;
 977                 goto end_put_session;
 978         }
 979
 980         /*
 981          * Send stream and *DON'T* ignore the sent flag so every viewer
 982          * streams that were not sent from that point will be sent to
 983          * the viewer.
 984          */
 985         ret = send_viewer_streams(conn->sock, session, 0);
 986         if (ret < 0) {
 987                 goto end_put_session;
 988         }
 989
 990 end_put_session:
 991         if (session) {
 992                 session_put(session);
 993         }
 994 error:
 995         return ret;
 996 }
 997
 998 /*
 999  * Send the viewer the list of current sessions.
1000  */
1001 static
1002 int viewer_attach_session(struct relay_connection *conn)
1003 {
1004         int send_streams = 0;
1005         ssize_t ret;
1006         uint32_t nb_streams = 0;
1007         enum lttng_viewer_seek seek_type;
1008         struct lttng_viewer_attach_session_request request;
1009         struct lttng_viewer_attach_session_response response;
1010         struct relay_session *session = NULL;
1011         bool closed = false;
1012
1013         assert(conn);
1014
1015         health_code_update();
1016
1017         /* Receive the request from the connected client. */
1018         ret = recv_request(conn->sock, &request, sizeof(request));
1019         if (ret < 0) {
1020                 goto error;
1021         }
1022
1023         health_code_update();
1024
1025         memset(&response, 0, sizeof(response));
1026
1027         if (!conn->viewer_session) {
1028                 DBG("Client trying to attach before creating a live viewer session");
1029                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NO_SESSION);
1030                 goto send_reply;
1031         }
1032
1033         session = session_get_by_id(be64toh(request.session_id));
1034         if (!session) {
1035                 DBG("Relay session %" PRIu64 " not found",
1036                                 be64toh(request.session_id));
1037                 response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
1038                 goto send_reply;
1039         }
1040         DBG("Attach session ID %" PRIu64 " received",
1041                 be64toh(request.session_id));
1042
1043         if (session->live_timer == 0) {
1044                 DBG("Not live session");
1045                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NOT_LIVE);
1046                 goto send_reply;
1047         }
1048
1049         send_streams = 1;
1050         ret = viewer_session_attach(conn->viewer_session, session);
1051         if (ret) {
1052                 DBG("Already a viewer attached");
1053                 response.status = htobe32(LTTNG_VIEWER_ATTACH_ALREADY);
1054                 goto send_reply;
1055         }
1056
1057         switch (be32toh(request.seek)) {
1058         case LTTNG_VIEWER_SEEK_BEGINNING:
1059         case LTTNG_VIEWER_SEEK_LAST:
1060                 response.status = htobe32(LTTNG_VIEWER_ATTACH_OK);
1061                 seek_type = be32toh(request.seek);
1062                 break;
1063         default:
1064                 ERR("Wrong seek parameter");
1065                 response.status = htobe32(LTTNG_VIEWER_ATTACH_SEEK_ERR);
1066                 send_streams = 0;
1067                 goto send_reply;
1068         }
1069
1070         ret = make_viewer_streams(session, seek_type, &nb_streams, NULL,
1071                         NULL, &closed);
1072         if (ret < 0) {
1073                 goto end_put_session;
1074         }
1075         response.streams_count = htobe32(nb_streams);
1076
1077         /*
1078          * If the session is closed when the viewer is attaching, it
1079          * means some of the streams may have been concurrently removed,
1080          * so we don't allow the viewer to attach, even if there are
1081          * streams available.
1082          */
1083         if (closed) {
1084                 send_streams = 0;
1085                 response.streams_count = 0;
1086                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
1087                 goto send_reply;
1088         }
1089
1090 send_reply:
1091         health_code_update();
1092         ret = send_response(conn->sock, &response, sizeof(response));
1093         if (ret < 0) {
1094                 goto end_put_session;
1095         }
1096         health_code_update();
1097
1098         /*
1099          * Unknown or empty session, just return gracefully, the viewer
1100          * knows what is happening.
1101          */
1102         if (!send_streams || !nb_streams) {
1103                 ret = 0;
1104                 goto end_put_session;
1105         }
1106
1107         /* Send stream and ignore the sent flag. */
1108         ret = send_viewer_streams(conn->sock, session, 1);
1109         if (ret < 0) {
1110                 goto end_put_session;
1111         }
1112
1113 end_put_session:
1114         if (session) {
1115                 session_put(session);
1116         }
1117 error:
1118         return ret;
1119 }
1120
1121 /*
1122  * Open the index file if needed for the given vstream.
1123  *
1124  * If an index file is successfully opened, the vstream index_fd set with
1125  * it.
1126  *
1127  * Return 0 on success, a negative value on error (-ENOENT if not ready yet).
1128  *
1129  * Called with rstream lock held.
1130  */
1131 static int try_open_index(struct relay_viewer_stream *vstream,
1132                 struct relay_stream *rstream)
1133 {
1134         int ret = 0;
1135
1136         if (vstream->index_fd) {
1137                 goto end;
1138         }
1139
1140         /*
1141          * First time, we open the index file and at least one index is ready.
1142          */
1143         if (rstream->index_received_seqcount == 0) {
1144                 ret = -ENOENT;
1145                 goto end;
1146         }
1147         ret = index_open(vstream->path_name, vstream->channel_name,
1148                         vstream->stream->tracefile_count,
1149                         vstream->current_tracefile_id);
1150         if (ret >= 0) {
1151                 vstream->index_fd = stream_fd_create(ret);
1152                 if (!vstream->index_fd) {
1153                         if (close(ret)) {
1154                                 PERROR("close");
1155                         }
1156                         ret = -1;
1157                 } else {
1158                         ret = 0;
1159                 }
1160                 goto end;
1161         }
1162
1163 end:
1164         return ret;
1165 }
1166
1167 /*
1168  * Check the status of the index for the given stream. This function
1169  * updates the index structure if needed and can put (close) the vstream
1170  * in the HUP situation.
1171  *
1172  * Return 0 means that we can proceed with the index. A value of 1 means
1173  * that the index has been updated and is ready to be sent to the
1174  * client. A negative value indicates an error that can't be handled.
1175  *
1176  * Called with rstream lock held.
1177  */
1178 static int check_index_status(struct relay_viewer_stream *vstream,
1179                 struct relay_stream *rstream, struct ctf_trace *trace,
1180                 struct lttng_viewer_index *index)
1181 {
1182         int ret;
1183
1184         if (trace->session->connection_closed
1185                         && rstream->index_received_seqcount
1186                                 == vstream->index_sent_seqcount) {
1187                 /* Last index sent and session connection is closed. */
1188                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1189                 goto hup;
1190         } else if (rstream->beacon_ts_end != -1ULL &&
1191                         rstream->index_received_seqcount
1192                                 == vstream->index_sent_seqcount) {
1193                 /*
1194                  * We've received a synchronization beacon and the last index
1195                  * available has been sent, the index for now is inactive.
1196                  *
1197                  * In this case, we have received a beacon which allows us to
1198                  * inform the client of a time interval during which we can
1199                  * guarantee that there are no events to read (and never will
1200                  * be).
1201                  */
1202                 index->status = htobe32(LTTNG_VIEWER_INDEX_INACTIVE);
1203                 index->timestamp_end = htobe64(rstream->beacon_ts_end);
1204                 index->stream_id = htobe64(rstream->ctf_stream_id);
1205                 goto index_ready;
1206         } else if (rstream->index_received_seqcount
1207                         == vstream->index_sent_seqcount) {
1208                 /*
1209                  * This checks whether received == sent seqcount. In
1210                  * this case, we have not received a beacon. Therefore,
1211                  * we can only ask the client to retry later.
1212                  */
1213                 index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1214                 goto index_ready;
1215         } else if (!tracefile_array_seq_in_file(rstream->tfa,
1216                         vstream->current_tracefile_id,
1217                         vstream->index_sent_seqcount)) {
1218                 /*
1219                  * The next index we want to send cannot be read either
1220                  * because we need to perform a rotation, or due to
1221                  * the producer having overwritten its trace file.
1222                  */
1223                 DBG("Viewer stream %" PRIu64 " rotation",
1224                                 vstream->stream->stream_handle);
1225                 ret = viewer_stream_rotate(vstream);
1226                 if (ret < 0) {
1227                         goto end;
1228                 } else if (ret == 1) {
1229                         /* EOF across entire stream. */
1230                         index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1231                         goto hup;
1232                 }
1233                 /*
1234                  * If we have been pushed due to overwrite, it
1235                  * necessarily means there is data that can be read in
1236                  * the stream. If we rotated because we reached the end
1237                  * of a tracefile, it means the following tracefile
1238                  * needs to contain at least one index, else we would
1239                  * have already returned LTTNG_VIEWER_INDEX_RETRY to the
1240                  * viewer. The updated index_sent_seqcount needs to
1241                  * point to a readable index entry now.
1242                  *
1243                  * In the case where we "rotate" on a single file, we
1244                  * can end up in a case where the requested index is
1245                  * still unavailable.
1246                  */
1247                 if (rstream->tracefile_count == 1 &&
1248                                 !tracefile_array_seq_in_file(
1249                                         rstream->tfa,
1250                                         vstream->current_tracefile_id,
1251                                         vstream->index_sent_seqcount)) {
1252                         index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1253                         goto index_ready;
1254                 }
1255                 assert(tracefile_array_seq_in_file(rstream->tfa,
1256                                 vstream->current_tracefile_id,
1257                                 vstream->index_sent_seqcount));
1258         }
1259         /* ret == 0 means successful so we continue. */
1260         ret = 0;
1261 end:
1262         return ret;
1263
1264 hup:
1265         viewer_stream_put(vstream);
1266 index_ready:
1267         return 1;
1268 }
1269
1270 /*
1271  * Send the next index for a stream.
1272  *
1273  * Return 0 on success or else a negative value.
1274  */
1275 static
1276 int viewer_get_next_index(struct relay_connection *conn)
1277 {
1278         int ret;
1279         ssize_t read_ret;
1280         struct lttng_viewer_get_next_index request_index;
1281         struct lttng_viewer_index viewer_index;
1282         struct ctf_packet_index packet_index;
1283         struct relay_viewer_stream *vstream = NULL;
1284         struct relay_stream *rstream = NULL;
1285         struct ctf_trace *ctf_trace = NULL;
1286         struct relay_viewer_stream *metadata_viewer_stream = NULL;
1287
1288         assert(conn);
1289
1290         DBG("Viewer get next index");
1291
1292         memset(&viewer_index, 0, sizeof(viewer_index));
1293         health_code_update();
1294
1295         ret = recv_request(conn->sock, &request_index, sizeof(request_index));
1296         if (ret < 0) {
1297                 goto end;
1298         }
1299         health_code_update();
1300
1301         vstream = viewer_stream_get_by_id(be64toh(request_index.stream_id));
1302         if (!vstream) {
1303                 DBG("Client requested index of unknown stream id %" PRIu64,
1304                                 be64toh(request_index.stream_id));
1305                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1306                 goto send_reply;
1307         }
1308
1309         /* Use back. ref. Protected by refcounts. */
1310         rstream = vstream->stream;
1311         ctf_trace = rstream->trace;
1312
1313         /* metadata_viewer_stream may be NULL. */
1314         metadata_viewer_stream =
1315                         ctf_trace_get_viewer_metadata_stream(ctf_trace);
1316
1317         pthread_mutex_lock(&rstream->lock);
1318
1319         /*
1320          * The viewer should not ask for index on metadata stream.
1321          */
1322         if (rstream->is_metadata) {
1323                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1324                 goto send_reply;
1325         }
1326
1327         /* Try to open an index if one is needed for that stream. */
1328         ret = try_open_index(vstream, rstream);
1329         if (ret < 0) {
1330                 if (ret == -ENOENT) {
1331                         /*
1332                          * The index is created only when the first data
1333                          * packet arrives, it might not be ready at the
1334                          * beginning of the session
1335                          */
1336                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1337                 } else {
1338                         /* Unhandled error. */
1339                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1340                 }
1341                 goto send_reply;
1342         }
1343
1344         ret = check_index_status(vstream, rstream, ctf_trace, &viewer_index);
1345         if (ret < 0) {
1346                 goto error_put;
1347         } else if (ret == 1) {
1348                 /*
1349                  * We have no index to send and check_index_status has populated
1350                  * viewer_index's status.
1351                  */
1352                 goto send_reply;
1353         }
1354         /* At this point, ret is 0 thus we will be able to read the index. */
1355         assert(!ret);
1356
1357         /*
1358          * vstream->stream_fd may be NULL if it has been closed by
1359          * tracefile rotation, or if we are at the beginning of the
1360          * stream. We open the data stream file here to protect against
1361          * overwrite caused by tracefile rotation (in association with
1362          * unlink performed before overwrite).
1363          */
1364         if (!vstream->stream_fd) {
1365                 char fullpath[PATH_MAX];
1366
1367                 if (vstream->stream->tracefile_count > 0) {
1368                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64,
1369                                         vstream->path_name,
1370                                         vstream->channel_name,
1371                                         vstream->current_tracefile_id);
1372                 } else {
1373                         ret = snprintf(fullpath, PATH_MAX, "%s/%s",
1374                                         vstream->path_name,
1375                                         vstream->channel_name);
1376                 }
1377                 if (ret < 0) {
1378                         goto error_put;
1379                 }
1380                 ret = open(fullpath, O_RDONLY);
1381                 if (ret < 0) {
1382                         PERROR("Relay opening trace file");
1383                         goto error_put;
1384                 }
1385                 vstream->stream_fd = stream_fd_create(ret);
1386                 if (!vstream->stream_fd) {
1387                         if (close(ret)) {
1388                                 PERROR("close");
1389                         }
1390                         goto error_put;
1391                 }
1392         }
1393
1394         ret = check_new_streams(conn);
1395         if (ret < 0) {
1396                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1397                 goto send_reply;
1398         } else if (ret == 1) {
1399                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1400         }
1401
1402         read_ret = lttng_read(vstream->index_fd->fd, &packet_index,
1403                         sizeof(packet_index));
1404         if (read_ret < sizeof(packet_index)) {
1405                 ERR("Relay reading index file %d returned %zd",
1406                         vstream->index_fd->fd, read_ret);
1407                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1408                 goto send_reply;
1409         } else {
1410                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_OK);
1411                 vstream->index_sent_seqcount++;
1412         }
1413
1414         /*
1415          * Indexes are stored in big endian, no need to switch before sending.
1416          */
1417         DBG("Sending viewer index for stream %" PRIu64 " offset %" PRIu64,
1418                 rstream->stream_handle,
1419                 be64toh(packet_index.offset));
1420         viewer_index.offset = packet_index.offset;
1421         viewer_index.packet_size = packet_index.packet_size;
1422         viewer_index.content_size = packet_index.content_size;
1423         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1424         viewer_index.timestamp_end = packet_index.timestamp_end;
1425         viewer_index.events_discarded = packet_index.events_discarded;
1426         viewer_index.stream_id = packet_index.stream_id;
1427
1428 send_reply:
1429         if (rstream) {
1430                 pthread_mutex_unlock(&rstream->lock);
1431         }
1432
1433         if (metadata_viewer_stream) {
1434                 pthread_mutex_lock(&metadata_viewer_stream->stream->lock);
1435                 DBG("get next index metadata check: recv %" PRIu64
1436                                 " sent %" PRIu64,
1437                         metadata_viewer_stream->stream->metadata_received,
1438                         metadata_viewer_stream->metadata_sent);
1439                 if (!metadata_viewer_stream->stream->metadata_received ||
1440                                 metadata_viewer_stream->stream->metadata_received >
1441                                         metadata_viewer_stream->metadata_sent) {
1442                         viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1443                 }
1444                 pthread_mutex_unlock(&metadata_viewer_stream->stream->lock);
1445         }
1446
1447         viewer_index.flags = htobe32(viewer_index.flags);
1448         health_code_update();
1449
1450         ret = send_response(conn->sock, &viewer_index, sizeof(viewer_index));
1451         if (ret < 0) {
1452                 goto end;
1453         }
1454         health_code_update();
1455
1456         if (vstream) {
1457                 DBG("Index %" PRIu64 " for stream %" PRIu64 " sent",
1458                                 vstream->index_sent_seqcount,
1459                                 vstream->stream->stream_handle);
1460         }
1461 end:
1462         if (metadata_viewer_stream) {
1463                 viewer_stream_put(metadata_viewer_stream);
1464         }
1465         if (vstream) {
1466                 viewer_stream_put(vstream);
1467         }
1468         return ret;
1469
1470 error_put:
1471         pthread_mutex_unlock(&rstream->lock);
1472         if (metadata_viewer_stream) {
1473                 viewer_stream_put(metadata_viewer_stream);
1474         }
1475         viewer_stream_put(vstream);
1476         return ret;
1477 }
1478
1479 /*
1480  * Send the next index for a stream
1481  *
1482  * Return 0 on success or else a negative value.
1483  */
1484 static
1485 int viewer_get_packet(struct relay_connection *conn)
1486 {
1487         int ret, send_data = 0;
1488         char *data = NULL;
1489         uint32_t len = 0;
1490         ssize_t read_len;
1491         struct lttng_viewer_get_packet get_packet_info;
1492         struct lttng_viewer_trace_packet reply;
1493         struct relay_viewer_stream *vstream = NULL;
1494
1495         DBG2("Relay get data packet");
1496
1497         health_code_update();
1498
1499         ret = recv_request(conn->sock, &get_packet_info,
1500                         sizeof(get_packet_info));
1501         if (ret < 0) {
1502                 goto end;
1503         }
1504         health_code_update();
1505
1506         /* From this point on, the error label can be reached. */
1507         memset(&reply, 0, sizeof(reply));
1508
1509         vstream = viewer_stream_get_by_id(be64toh(get_packet_info.stream_id));
1510         if (!vstream) {
1511                 DBG("Client requested packet of unknown stream id %" PRIu64,
1512                                 be64toh(get_packet_info.stream_id));
1513                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1514                 goto send_reply_nolock;
1515         }
1516
1517         pthread_mutex_lock(&vstream->stream->lock);
1518
1519         len = be32toh(get_packet_info.len);
1520         data = zmalloc(len);
1521         if (!data) {
1522                 PERROR("relay data zmalloc");
1523                 goto error;
1524         }
1525
1526         ret = lseek(vstream->stream_fd->fd, be64toh(get_packet_info.offset),
1527                         SEEK_SET);
1528         if (ret < 0) {
1529                 PERROR("lseek fd %d to offset %" PRIu64, vstream->stream_fd->fd,
1530                         be64toh(get_packet_info.offset));
1531                 goto error;
1532         }
1533         read_len = lttng_read(vstream->stream_fd->fd, data, len);
1534         if (read_len < len) {
1535                 PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1536                                 vstream->stream_fd->fd,
1537                                 be64toh(get_packet_info.offset));
1538                 goto error;
1539         }
1540         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_OK);
1541         reply.len = htobe32(len);
1542         send_data = 1;
1543         goto send_reply;
1544
1545 error:
1546         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1547
1548 send_reply:
1549         if (vstream) {
1550                 pthread_mutex_unlock(&vstream->stream->lock);
1551         }
1552 send_reply_nolock:
1553         reply.flags = htobe32(reply.flags);
1554
1555         health_code_update();
1556
1557         ret = send_response(conn->sock, &reply, sizeof(reply));
1558         if (ret < 0) {
1559                 goto end_free;
1560         }
1561         health_code_update();
1562
1563         if (send_data) {
1564                 health_code_update();
1565                 ret = send_response(conn->sock, data, len);
1566                 if (ret < 0) {
1567                         goto end_free;
1568                 }
1569                 health_code_update();
1570         }
1571
1572         DBG("Sent %u bytes for stream %" PRIu64, len,
1573                         be64toh(get_packet_info.stream_id));
1574
1575 end_free:
1576         free(data);
1577 end:
1578         if (vstream) {
1579                 viewer_stream_put(vstream);
1580         }
1581         return ret;
1582 }
1583
1584 /*
1585  * Send the session's metadata
1586  *
1587  * Return 0 on success else a negative value.
1588  */
1589 static
1590 int viewer_get_metadata(struct relay_connection *conn)
1591 {
1592         int ret = 0;
1593         ssize_t read_len;
1594         uint64_t len = 0;
1595         char *data = NULL;
1596         struct lttng_viewer_get_metadata request;
1597         struct lttng_viewer_metadata_packet reply;
1598         struct relay_viewer_stream *vstream = NULL;
1599
1600         assert(conn);
1601
1602         DBG("Relay get metadata");
1603
1604         health_code_update();
1605
1606         ret = recv_request(conn->sock, &request, sizeof(request));
1607         if (ret < 0) {
1608                 goto end;
1609         }
1610         health_code_update();
1611
1612         memset(&reply, 0, sizeof(reply));
1613
1614         vstream = viewer_stream_get_by_id(be64toh(request.stream_id));
1615         if (!vstream) {
1616                 /*
1617                  * The metadata stream can be closed by a CLOSE command
1618                  * just before we attach. It can also be closed by
1619                  * per-pid tracing during tracing. Therefore, it is
1620                  * possible that we cannot find this viewer stream.
1621                  * Reply back to the client with an error if we cannot
1622                  * find it.
1623                  */
1624                 DBG("Client requested metadata of unknown stream id %" PRIu64,
1625                                 be64toh(request.stream_id));
1626                 reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1627                 goto send_reply;
1628         }
1629         pthread_mutex_lock(&vstream->stream->lock);
1630         if (!vstream->stream->is_metadata) {
1631                 ERR("Invalid metadata stream");
1632                 goto error;
1633         }
1634
1635         assert(vstream->metadata_sent <= vstream->stream->metadata_received);
1636
1637         len = vstream->stream->metadata_received - vstream->metadata_sent;
1638         if (len == 0) {
1639                 reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
1640                 goto send_reply;
1641         }
1642
1643         /* first time, we open the metadata file */
1644         if (!vstream->stream_fd) {
1645                 char fullpath[PATH_MAX];
1646
1647                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", vstream->path_name,
1648                                 vstream->channel_name);
1649                 if (ret < 0) {
1650                         goto error;
1651                 }
1652                 ret = open(fullpath, O_RDONLY);
1653                 if (ret < 0) {
1654                         PERROR("Relay opening metadata file");
1655                         goto error;
1656                 }
1657                 vstream->stream_fd = stream_fd_create(ret);
1658                 if (!vstream->stream_fd) {
1659                         if (close(ret)) {
1660                                 PERROR("close");
1661                         }
1662                         goto error;
1663                 }
1664         }
1665
1666         reply.len = htobe64(len);
1667         data = zmalloc(len);
1668         if (!data) {
1669                 PERROR("viewer metadata zmalloc");
1670                 goto error;
1671         }
1672
1673         read_len = lttng_read(vstream->stream_fd->fd, data, len);
1674         if (read_len < len) {
1675                 PERROR("Relay reading metadata file");
1676                 goto error;
1677         }
1678         vstream->metadata_sent += read_len;
1679         if (vstream->metadata_sent == vstream->stream->metadata_received
1680                         && vstream->stream->closed) {
1681                 /* Release ownership for the viewer metadata stream. */
1682                 viewer_stream_put(vstream);
1683         }
1684
1685         reply.status = htobe32(LTTNG_VIEWER_METADATA_OK);
1686
1687         goto send_reply;
1688
1689 error:
1690         reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1691
1692 send_reply:
1693         health_code_update();
1694         if (vstream) {
1695                 pthread_mutex_unlock(&vstream->stream->lock);
1696         }
1697         ret = send_response(conn->sock, &reply, sizeof(reply));
1698         if (ret < 0) {
1699                 goto end_free;
1700         }
1701         health_code_update();
1702
1703         if (len > 0) {
1704                 ret = send_response(conn->sock, data, len);
1705                 if (ret < 0) {
1706                         goto end_free;
1707                 }
1708         }
1709
1710         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1711                         be64toh(request.stream_id));
1712
1713         DBG("Metadata sent");
1714
1715 end_free:
1716         free(data);
1717 end:
1718         if (vstream) {
1719                 viewer_stream_put(vstream);
1720         }
1721         return ret;
1722 }
1723
1724 /*
1725  * Create a viewer session.
1726  *
1727  * Return 0 on success or else a negative value.
1728  */
1729 static
1730 int viewer_create_session(struct relay_connection *conn)
1731 {
1732         int ret;
1733         struct lttng_viewer_create_session_response resp;
1734
1735         DBG("Viewer create session received");
1736
1737         memset(&resp, 0, sizeof(resp));
1738         resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_OK);
1739         conn->viewer_session = viewer_session_create();
1740         if (!conn->viewer_session) {
1741                 ERR("Allocation viewer session");
1742                 resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_ERR);
1743                 goto send_reply;
1744         }
1745
1746 send_reply:
1747         health_code_update();
1748         ret = send_response(conn->sock, &resp, sizeof(resp));
1749         if (ret < 0) {
1750                 goto end;
1751         }
1752         health_code_update();
1753         ret = 0;
1754
1755 end:
1756         return ret;
1757 }
1758
1759
1760 /*
1761  * live_relay_unknown_command: send -1 if received unknown command
1762  */
1763 static
1764 void live_relay_unknown_command(struct relay_connection *conn)
1765 {
1766         struct lttcomm_relayd_generic_reply reply;
1767
1768         memset(&reply, 0, sizeof(reply));
1769         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1770         (void) send_response(conn->sock, &reply, sizeof(reply));
1771 }
1772
1773 /*
1774  * Process the commands received on the control socket
1775  */
1776 static
1777 int process_control(struct lttng_viewer_cmd *recv_hdr,
1778                 struct relay_connection *conn)
1779 {
1780         int ret = 0;
1781         uint32_t msg_value;
1782
1783         msg_value = be32toh(recv_hdr->cmd);
1784
1785         /*
1786          * Make sure we've done the version check before any command other then a
1787          * new client connection.
1788          */
1789         if (msg_value != LTTNG_VIEWER_CONNECT && !conn->version_check_done) {
1790                 ERR("Viewer conn value %" PRIu32 " before version check", msg_value);
1791                 ret = -1;
1792                 goto end;
1793         }
1794
1795         switch (msg_value) {
1796         case LTTNG_VIEWER_CONNECT:
1797                 ret = viewer_connect(conn);
1798                 break;
1799         case LTTNG_VIEWER_LIST_SESSIONS:
1800                 ret = viewer_list_sessions(conn);
1801                 break;
1802         case LTTNG_VIEWER_ATTACH_SESSION:
1803                 ret = viewer_attach_session(conn);
1804                 break;
1805         case LTTNG_VIEWER_GET_NEXT_INDEX:
1806                 ret = viewer_get_next_index(conn);
1807                 break;
1808         case LTTNG_VIEWER_GET_PACKET:
1809                 ret = viewer_get_packet(conn);
1810                 break;
1811         case LTTNG_VIEWER_GET_METADATA:
1812                 ret = viewer_get_metadata(conn);
1813                 break;
1814         case LTTNG_VIEWER_GET_NEW_STREAMS:
1815                 ret = viewer_get_new_streams(conn);
1816                 break;
1817         case LTTNG_VIEWER_CREATE_SESSION:
1818                 ret = viewer_create_session(conn);
1819                 break;
1820         default:
1821                 ERR("Received unknown viewer command (%u)",
1822                                 be32toh(recv_hdr->cmd));
1823                 live_relay_unknown_command(conn);
1824                 ret = -1;
1825                 goto end;
1826         }
1827
1828 end:
1829         return ret;
1830 }
1831
1832 static
1833 void cleanup_connection_pollfd(struct lttng_poll_event *events, int pollfd)
1834 {
1835         int ret;
1836
1837         (void) lttng_poll_del(events, pollfd);
1838
1839         ret = close(pollfd);
1840         if (ret < 0) {
1841                 ERR("Closing pollfd %d", pollfd);
1842         }
1843 }
1844
1845 /*
1846  * This thread does the actual work
1847  */
1848 static
1849 void *thread_worker(void *data)
1850 {
1851         int ret, err = -1;
1852         uint32_t nb_fd;
1853         struct lttng_poll_event events;
1854         struct lttng_ht *viewer_connections_ht;
1855         struct lttng_ht_iter iter;
1856         struct lttng_viewer_cmd recv_hdr;
1857         struct relay_connection *destroy_conn;
1858
1859         DBG("[thread] Live viewer relay worker started");
1860
1861         rcu_register_thread();
1862
1863         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1864
1865         if (testpoint(relayd_thread_live_worker)) {
1866                 goto error_testpoint;
1867         }
1868
1869         /* table of connections indexed on socket */
1870         viewer_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1871         if (!viewer_connections_ht) {
1872                 goto viewer_connections_ht_error;
1873         }
1874
1875         ret = create_thread_poll_set(&events, 2);
1876         if (ret < 0) {
1877                 goto error_poll_create;
1878         }
1879
1880         ret = lttng_poll_add(&events, live_conn_pipe[0], LPOLLIN | LPOLLRDHUP);
1881         if (ret < 0) {
1882                 goto error;
1883         }
1884
1885 restart:
1886         while (1) {
1887                 int i;
1888
1889                 health_code_update();
1890
1891                 /* Infinite blocking call, waiting for transmission */
1892                 DBG3("Relayd live viewer worker thread polling...");
1893                 health_poll_entry();
1894                 ret = lttng_poll_wait(&events, -1);
1895                 health_poll_exit();
1896                 if (ret < 0) {
1897                         /*
1898                          * Restart interrupted system call.
1899                          */
1900                         if (errno == EINTR) {
1901                                 goto restart;
1902                         }
1903                         goto error;
1904                 }
1905
1906                 nb_fd = ret;
1907
1908                 /*
1909                  * Process control. The control connection is prioritised so we don't
1910                  * starve it with high throughput tracing data on the data
1911                  * connection.
1912                  */
1913                 for (i = 0; i < nb_fd; i++) {
1914                         /* Fetch once the poll data */
1915                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1916                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1917
1918                         health_code_update();
1919
1920                         if (!revents) {
1921                                 /* No activity for this FD (poll implementation). */
1922                                 continue;
1923                         }
1924
1925                         /* Thread quit pipe has been closed. Killing thread. */
1926                         ret = check_thread_quit_pipe(pollfd, revents);
1927                         if (ret) {
1928                                 err = 0;
1929                                 goto exit;
1930                         }
1931
1932                         /* Inspect the relay conn pipe for new connection. */
1933                         if (pollfd == live_conn_pipe[0]) {
1934                                 if (revents & LPOLLIN) {
1935                                         struct relay_connection *conn;
1936
1937                                         ret = lttng_read(live_conn_pipe[0],
1938                                                         &conn, sizeof(conn));
1939                                         if (ret < 0) {
1940                                                 goto error;
1941                                         }
1942                                         lttng_poll_add(&events, conn->sock->fd,
1943                                                         LPOLLIN | LPOLLRDHUP);
1944                                         connection_ht_add(viewer_connections_ht, conn);
1945                                         DBG("Connection socket %d added to poll", conn->sock->fd);
1946                                 } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1947                                         ERR("Relay live pipe error");
1948                                         goto error;
1949                                 } else {
1950                                         ERR("Unexpected poll events %u for sock %d", revents, pollfd);
1951                                         goto error;
1952                                 }
1953                         } else {
1954                                 /* Connection activity. */
1955                                 struct relay_connection *conn;
1956
1957                                 conn = connection_get_by_sock(viewer_connections_ht, pollfd);
1958                                 if (!conn) {
1959                                         continue;
1960                                 }
1961
1962                                 if (revents & LPOLLIN) {
1963                                         ret = conn->sock->ops->recvmsg(conn->sock, &recv_hdr,
1964                                                         sizeof(recv_hdr), 0);
1965                                         if (ret <= 0) {
1966                                                 /* Connection closed. */
1967                                                 cleanup_connection_pollfd(&events, pollfd);
1968                                                 /* Put "create" ownership reference. */
1969                                                 connection_put(conn);
1970                                                 DBG("Viewer control conn closed with %d", pollfd);
1971                                         } else {
1972                                                 ret = process_control(&recv_hdr, conn);
1973                                                 if (ret < 0) {
1974                                                         /* Clear the session on error. */
1975                                                         cleanup_connection_pollfd(&events, pollfd);
1976                                                         /* Put "create" ownership reference. */
1977                                                         connection_put(conn);
1978                                                         DBG("Viewer connection closed with %d", pollfd);
1979                                                 }
1980                                         }
1981                                 } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1982                                         cleanup_connection_pollfd(&events, pollfd);
1983                                         /* Put "create" ownership reference. */
1984                                         connection_put(conn);
1985                                 } else {
1986                                         ERR("Unexpected poll events %u for sock %d", revents, pollfd);
1987                                         connection_put(conn);
1988                                         goto error;
1989                                 }
1990                                 /* Put local "get_by_sock" reference. */
1991                                 connection_put(conn);
1992                         }
1993                 }
1994         }
1995
1996 exit:
1997 error:
1998         lttng_poll_clean(&events);
1999
2000         /* Cleanup reamaining connection object. */
2001         rcu_read_lock();
2002         cds_lfht_for_each_entry(viewer_connections_ht->ht, &iter.iter,
2003                         destroy_conn,
2004                         sock_n.node) {
2005                 health_code_update();
2006                 connection_put(destroy_conn);
2007         }
2008         rcu_read_unlock();
2009 error_poll_create:
2010         lttng_ht_destroy(viewer_connections_ht);
2011 viewer_connections_ht_error:
2012         /* Close relay conn pipes */
2013         utils_close_pipe(live_conn_pipe);
2014         if (err) {
2015                 DBG("Viewer worker thread exited with error");
2016         }
2017         DBG("Viewer worker thread cleanup complete");
2018 error_testpoint:
2019         if (err) {
2020                 health_error();
2021                 ERR("Health error occurred in %s", __func__);
2022         }
2023         health_unregister(health_relayd);
2024         if (lttng_relay_stop_threads()) {
2025                 ERR("Error stopping threads");
2026         }
2027         rcu_unregister_thread();
2028         return NULL;
2029 }
2030
2031 /*
2032  * Create the relay command pipe to wake thread_manage_apps.
2033  * Closed in cleanup().
2034  */
2035 static int create_conn_pipe(void)
2036 {
2037         return utils_create_pipe_cloexec(live_conn_pipe);
2038 }
2039
2040 int relayd_live_join(void)
2041 {
2042         int ret, retval = 0;
2043         void *status;
2044
2045         ret = pthread_join(live_listener_thread, &status);
2046         if (ret) {
2047                 errno = ret;
2048                 PERROR("pthread_join live listener");
2049                 retval = -1;
2050         }
2051
2052         ret = pthread_join(live_worker_thread, &status);
2053         if (ret) {
2054                 errno = ret;
2055                 PERROR("pthread_join live worker");
2056                 retval = -1;
2057         }
2058
2059         ret = pthread_join(live_dispatcher_thread, &status);
2060         if (ret) {
2061                 errno = ret;
2062                 PERROR("pthread_join live dispatcher");
2063                 retval = -1;
2064         }
2065
2066         cleanup_relayd_live();
2067
2068         return retval;
2069 }
2070
2071 /*
2072  * main
2073  */
2074 int relayd_live_create(struct lttng_uri *uri)
2075 {
2076         int ret = 0, retval = 0;
2077         void *status;
2078         int is_root;
2079
2080         if (!uri) {
2081                 retval = -1;
2082                 goto exit_init_data;
2083         }
2084         live_uri = uri;
2085
2086         /* Check if daemon is UID = 0 */
2087         is_root = !getuid();
2088
2089         if (!is_root) {
2090                 if (live_uri->port < 1024) {
2091                         ERR("Need to be root to use ports < 1024");
2092                         retval = -1;
2093                         goto exit_init_data;
2094                 }
2095         }
2096
2097         /* Setup the thread apps communication pipe. */
2098         if (create_conn_pipe()) {
2099                 retval = -1;
2100                 goto exit_init_data;
2101         }
2102
2103         /* Init relay command queue. */
2104         cds_wfcq_init(&viewer_conn_queue.head, &viewer_conn_queue.tail);
2105
2106         /* Set up max poll set size */
2107         if (lttng_poll_set_max_size()) {
2108                 retval = -1;
2109                 goto exit_init_data;
2110         }
2111
2112         /* Setup the dispatcher thread */
2113         ret = pthread_create(&live_dispatcher_thread, NULL,
2114                         thread_dispatcher, (void *) NULL);
2115         if (ret) {
2116                 errno = ret;
2117                 PERROR("pthread_create viewer dispatcher");
2118                 retval = -1;
2119                 goto exit_dispatcher_thread;
2120         }
2121
2122         /* Setup the worker thread */
2123         ret = pthread_create(&live_worker_thread, NULL,
2124                         thread_worker, NULL);
2125         if (ret) {
2126                 errno = ret;
2127                 PERROR("pthread_create viewer worker");
2128                 retval = -1;
2129                 goto exit_worker_thread;
2130         }
2131
2132         /* Setup the listener thread */
2133         ret = pthread_create(&live_listener_thread, NULL,
2134                         thread_listener, (void *) NULL);
2135         if (ret) {
2136                 errno = ret;
2137                 PERROR("pthread_create viewer listener");
2138                 retval = -1;
2139                 goto exit_listener_thread;
2140         }
2141
2142         /*
2143          * All OK, started all threads.
2144          */
2145         return retval;
2146
2147         /*
2148          * Join on the live_listener_thread should anything be added after
2149          * the live_listener thread's creation.
2150          */
2151
2152 exit_listener_thread:
2153
2154         ret = pthread_join(live_worker_thread, &status);
2155         if (ret) {
2156                 errno = ret;
2157                 PERROR("pthread_join live worker");
2158                 retval = -1;
2159         }
2160 exit_worker_thread:
2161
2162         ret = pthread_join(live_dispatcher_thread, &status);
2163         if (ret) {
2164                 errno = ret;
2165                 PERROR("pthread_join live dispatcher");
2166                 retval = -1;
2167         }
2168 exit_dispatcher_thread:
2169
2170 exit_init_data:
2171         cleanup_relayd_live();
2172
2173         return retval;
2174 }