src/bin/lttng-relayd/live.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <getopt.h>
  21 #include <grp.h>
  22 #include <limits.h>
  23 #include <pthread.h>
  24 #include <signal.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sys/mman.h>
  29 #include <sys/mount.h>
  30 #include <sys/resource.h>
  31 #include <sys/socket.h>
  32 #include <sys/stat.h>
  33 #include <sys/types.h>
  34 #include <sys/wait.h>
  35 #include <inttypes.h>
  36 #include <urcu/futex.h>
  37 #include <urcu/uatomic.h>
  38 #include <unistd.h>
  39 #include <fcntl.h>
  40 #include <config.h>
  41
  42 #include <lttng/lttng.h>
  43 #include <common/common.h>
  44 #include <common/compat/poll.h>
  45 #include <common/compat/socket.h>
  46 #include <common/compat/endian.h>
  47 #include <common/defaults.h>
  48 #include <common/futex.h>
  49 #include <common/index/index.h>
  50 #include <common/sessiond-comm/sessiond-comm.h>
  51 #include <common/sessiond-comm/inet.h>
  52 #include <common/sessiond-comm/relayd.h>
  53 #include <common/uri.h>
  54 #include <common/utils.h>
  55
  56 #include "cmd.h"
  57 #include "live.h"
  58 #include "lttng-relayd.h"
  59 #include "utils.h"
  60 #include "health-relayd.h"
  61 #include "testpoint.h"
  62 #include "viewer-stream.h"
  63 #include "stream.h"
  64 #include "session.h"
  65 #include "ctf-trace.h"
  66 #include "connection.h"
  67
  68 static struct lttng_uri *live_uri;
  69
  70 /*
  71  * This pipe is used to inform the worker thread that a command is queued and
  72  * ready to be processed.
  73  */
  74 static int live_conn_pipe[2] = { -1, -1 };
  75
  76 /* Shared between threads */
  77 static int live_dispatch_thread_exit;
  78
  79 static pthread_t live_listener_thread;
  80 static pthread_t live_dispatcher_thread;
  81 static pthread_t live_worker_thread;
  82
  83 /*
  84  * Relay command queue.
  85  *
  86  * The live_thread_listener and live_thread_dispatcher communicate with this
  87  * queue.
  88  */
  89 static struct relay_conn_queue viewer_conn_queue;
  90
  91 static uint64_t last_relay_viewer_session_id;
  92
  93 /*
  94  * Cleanup the daemon
  95  */
  96 static
  97 void cleanup_relayd_live(void)
  98 {
  99         DBG("Cleaning up");
 100
 101         free(live_uri);
 102 }
 103
 104 /*
 105  * Receive a request buffer using a given socket, destination allocated buffer
 106  * of length size.
 107  *
 108  * Return the size of the received message or else a negative value on error
 109  * with errno being set by recvmsg() syscall.
 110  */
 111 static
 112 ssize_t recv_request(struct lttcomm_sock *sock, void *buf, size_t size)
 113 {
 114         ssize_t ret;
 115
 116         assert(sock);
 117         assert(buf);
 118
 119         ret = sock->ops->recvmsg(sock, buf, size, 0);
 120         if (ret < 0 || ret != size) {
 121                 if (ret == 0) {
 122                         /* Orderly shutdown. Not necessary to print an error. */
 123                         DBG("Socket %d did an orderly shutdown", sock->fd);
 124                 } else {
 125                         ERR("Relay failed to receive request.");
 126                 }
 127                 ret = -1;
 128         }
 129
 130         return ret;
 131 }
 132
 133 /*
 134  * Send a response buffer using a given socket, source allocated buffer of
 135  * length size.
 136  *
 137  * Return the size of the sent message or else a negative value on error with
 138  * errno being set by sendmsg() syscall.
 139  */
 140 static
 141 ssize_t send_response(struct lttcomm_sock *sock, void *buf, size_t size)
 142 {
 143         ssize_t ret;
 144
 145         assert(sock);
 146         assert(buf);
 147
 148         ret = sock->ops->sendmsg(sock, buf, size, 0);
 149         if (ret < 0) {
 150                 ERR("Relayd failed to send response.");
 151         }
 152
 153         return ret;
 154 }
 155
 156 /*
 157  * Atomically check if new streams got added in one of the sessions attached
 158  * and reset the flag to 0.
 159  *
 160  * Returns 1 if new streams got added, 0 if nothing changed, a negative value
 161  * on error.
 162  */
 163 static
 164 int check_new_streams(struct relay_connection *conn)
 165 {
 166         struct relay_session *session;
 167         unsigned long current_val;
 168         int ret = 0;
 169
 170         if (!conn->viewer_session) {
 171                 goto end;
 172         }
 173         cds_list_for_each_entry(session,
 174                         &conn->viewer_session->sessions_head,
 175                         viewer_session_list) {
 176                 current_val = uatomic_cmpxchg(&session->new_streams, 1, 0);
 177                 ret = current_val;
 178                 if (ret == 1) {
 179                         goto end;
 180                 }
 181         }
 182
 183 end:
 184         return ret;
 185 }
 186
 187 /*
 188  * Send viewer streams to the given socket. The ignore_sent_flag indicates if
 189  * this function should ignore the sent flag or not.
 190  *
 191  * Return 0 on success or else a negative value.
 192  */
 193 static
 194 ssize_t send_viewer_streams(struct lttcomm_sock *sock,
 195                 struct relay_session *session, unsigned int ignore_sent_flag)
 196 {
 197         ssize_t ret;
 198         struct lttng_viewer_stream send_stream;
 199         struct lttng_ht_iter iter;
 200         struct relay_viewer_stream *vstream;
 201
 202         assert(session);
 203
 204         rcu_read_lock();
 205
 206         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
 207                         stream_n.node) {
 208                 struct ctf_trace *ctf_trace;
 209
 210                 health_code_update();
 211
 212                 /* Ignore if not the same session. */
 213                 if (vstream->session_id != session->id ||
 214                                 (!ignore_sent_flag && vstream->sent_flag)) {
 215                         continue;
 216                 }
 217
 218                 ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
 219                                 vstream->path_name);
 220                 assert(ctf_trace);
 221
 222                 send_stream.id = htobe64(vstream->stream_handle);
 223                 send_stream.ctf_trace_id = htobe64(ctf_trace->id);
 224                 send_stream.metadata_flag = htobe32(vstream->metadata_flag);
 225                 strncpy(send_stream.path_name, vstream->path_name,
 226                                 sizeof(send_stream.path_name));
 227                 strncpy(send_stream.channel_name, vstream->channel_name,
 228                                 sizeof(send_stream.channel_name));
 229
 230                 DBG("Sending stream %" PRIu64 " to viewer", vstream->stream_handle);
 231                 ret = send_response(sock, &send_stream, sizeof(send_stream));
 232                 if (ret < 0) {
 233                         goto end_unlock;
 234                 }
 235                 vstream->sent_flag = 1;
 236         }
 237
 238         ret = 0;
 239
 240 end_unlock:
 241         rcu_read_unlock();
 242         return ret;
 243 }
 244
 245 /*
 246  * Create every viewer stream possible for the given session with the seek
 247  * type. Three counters *can* be return which are in order the total amount of
 248  * viewer stream of the session, the number of unsent stream and the number of
 249  * stream created. Those counters can be NULL and thus will be ignored.
 250  *
 251  * Return 0 on success or else a negative value.
 252  */
 253 static
 254 int make_viewer_streams(struct relay_session *session,
 255                 enum lttng_viewer_seek seek_t, uint32_t *nb_total, uint32_t *nb_unsent,
 256                 uint32_t *nb_created)
 257 {
 258         int ret;
 259         struct lttng_ht_iter iter;
 260         struct ctf_trace *ctf_trace;
 261
 262         assert(session);
 263
 264         /*
 265          * This is to make sure we create viewer streams for a full received
 266          * channel. For instance, if we have 8 streams for a channel that are
 267          * concurrently being flagged ready, we can end up creating just a subset
 268          * of the 8 streams (the ones that are flagged). This lock avoids this
 269          * limbo state.
 270          */
 271         pthread_mutex_lock(&session->viewer_ready_lock);
 272
 273         /*
 274          * Create viewer streams for relay streams that are ready to be used for a
 275          * the given session id only.
 276          */
 277         rcu_read_lock();
 278         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 279                         node.node) {
 280                 struct relay_stream *stream;
 281
 282                 health_code_update();
 283
 284                 if (ctf_trace->invalid_flag) {
 285                         continue;
 286                 }
 287
 288                 cds_list_for_each_entry(stream, &ctf_trace->stream_list, trace_list) {
 289                         struct relay_viewer_stream *vstream;
 290
 291                         if (!stream->viewer_ready) {
 292                                 continue;
 293                         }
 294
 295                         vstream = viewer_stream_find_by_id(stream->stream_handle);
 296                         if (!vstream) {
 297                                 vstream = viewer_stream_create(stream, seek_t, ctf_trace);
 298                                 if (!vstream) {
 299                                         ret = -1;
 300                                         goto error_unlock;
 301                                 }
 302                                 /* Acquire reference to ctf_trace. */
 303                                 ctf_trace_get_ref(ctf_trace);
 304
 305                                 if (nb_created) {
 306                                         /* Update number of created stream counter. */
 307                                         (*nb_created)++;
 308                                 }
 309                         } else if (!vstream->sent_flag && nb_unsent) {
 310                                 /* Update number of unsent stream counter. */
 311                                 (*nb_unsent)++;
 312                         }
 313                         /* Update number of total stream counter. */
 314                         if (nb_total) {
 315                                 (*nb_total)++;
 316                         }
 317                 }
 318         }
 319
 320         ret = 0;
 321
 322 error_unlock:
 323         rcu_read_unlock();
 324         pthread_mutex_unlock(&session->viewer_ready_lock);
 325         return ret;
 326 }
 327
 328 int relayd_live_stop(void)
 329 {
 330         /* Stop dispatch thread */
 331         CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
 332         futex_nto1_wake(&viewer_conn_queue.futex);
 333         return 0;
 334 }
 335
 336 /*
 337  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 338  */
 339 static
 340 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 341 {
 342         int ret;
 343
 344         if (events == NULL || size == 0) {
 345                 ret = -1;
 346                 goto error;
 347         }
 348
 349         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 350         if (ret < 0) {
 351                 goto error;
 352         }
 353
 354         /* Add quit pipe */
 355         ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
 356         if (ret < 0) {
 357                 goto error;
 358         }
 359
 360         return 0;
 361
 362 error:
 363         return ret;
 364 }
 365
 366 /*
 367  * Check if the thread quit pipe was triggered.
 368  *
 369  * Return 1 if it was triggered else 0;
 370  */
 371 static
 372 int check_thread_quit_pipe(int fd, uint32_t events)
 373 {
 374         if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
 375                 return 1;
 376         }
 377
 378         return 0;
 379 }
 380
 381 /*
 382  * Create and init socket from uri.
 383  */
 384 static
 385 struct lttcomm_sock *init_socket(struct lttng_uri *uri)
 386 {
 387         int ret;
 388         struct lttcomm_sock *sock = NULL;
 389
 390         sock = lttcomm_alloc_sock_from_uri(uri);
 391         if (sock == NULL) {
 392                 ERR("Allocating socket");
 393                 goto error;
 394         }
 395
 396         ret = lttcomm_create_sock(sock);
 397         if (ret < 0) {
 398                 goto error;
 399         }
 400         DBG("Listening on sock %d for live", sock->fd);
 401
 402         ret = sock->ops->bind(sock);
 403         if (ret < 0) {
 404                 goto error;
 405         }
 406
 407         ret = sock->ops->listen(sock, -1);
 408         if (ret < 0) {
 409                 goto error;
 410
 411         }
 412
 413         return sock;
 414
 415 error:
 416         if (sock) {
 417                 lttcomm_destroy_sock(sock);
 418         }
 419         return NULL;
 420 }
 421
 422 /*
 423  * This thread manages the listening for new connections on the network
 424  */
 425 static
 426 void *thread_listener(void *data)
 427 {
 428         int i, ret, pollfd, err = -1;
 429         uint32_t revents, nb_fd;
 430         struct lttng_poll_event events;
 431         struct lttcomm_sock *live_control_sock;
 432
 433         DBG("[thread] Relay live listener started");
 434
 435         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_LISTENER);
 436
 437         health_code_update();
 438
 439         live_control_sock = init_socket(live_uri);
 440         if (!live_control_sock) {
 441                 goto error_sock_control;
 442         }
 443
 444         /* Pass 2 as size here for the thread quit pipe and control sockets. */
 445         ret = create_thread_poll_set(&events, 2);
 446         if (ret < 0) {
 447                 goto error_create_poll;
 448         }
 449
 450         /* Add the control socket */
 451         ret = lttng_poll_add(&events, live_control_sock->fd, LPOLLIN | LPOLLRDHUP);
 452         if (ret < 0) {
 453                 goto error_poll_add;
 454         }
 455
 456         lttng_relay_notify_ready();
 457
 458         if (testpoint(relayd_thread_live_listener)) {
 459                 goto error_testpoint;
 460         }
 461
 462         while (1) {
 463                 health_code_update();
 464
 465                 DBG("Listener accepting live viewers connections");
 466
 467 restart:
 468                 health_poll_entry();
 469                 ret = lttng_poll_wait(&events, -1);
 470                 health_poll_exit();
 471                 if (ret < 0) {
 472                         /*
 473                          * Restart interrupted system call.
 474                          */
 475                         if (errno == EINTR) {
 476                                 goto restart;
 477                         }
 478                         goto error;
 479                 }
 480                 nb_fd = ret;
 481
 482                 DBG("Relay new viewer connection received");
 483                 for (i = 0; i < nb_fd; i++) {
 484                         health_code_update();
 485
 486                         /* Fetch once the poll data */
 487                         revents = LTTNG_POLL_GETEV(&events, i);
 488                         pollfd = LTTNG_POLL_GETFD(&events, i);
 489
 490                         if (!revents) {
 491                                 /* No activity for this FD (poll implementation). */
 492                                 continue;
 493                         }
 494
 495                         /* Thread quit pipe has been closed. Killing thread. */
 496                         ret = check_thread_quit_pipe(pollfd, revents);
 497                         if (ret) {
 498                                 err = 0;
 499                                 goto exit;
 500                         }
 501
 502                         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 503                                 ERR("socket poll error");
 504                                 goto error;
 505                         } else if (revents & LPOLLIN) {
 506                                 /*
 507                                  * Get allocated in this thread, enqueued to a global queue,
 508                                  * dequeued and freed in the worker thread.
 509                                  */
 510                                 int val = 1;
 511                                 struct relay_connection *new_conn;
 512                                 struct lttcomm_sock *newsock;
 513
 514                                 new_conn = connection_create();
 515                                 if (!new_conn) {
 516                                         goto error;
 517                                 }
 518
 519                                 newsock = live_control_sock->ops->accept(live_control_sock);
 520                                 if (!newsock) {
 521                                         PERROR("accepting control sock");
 522                                         connection_free(new_conn);
 523                                         goto error;
 524                                 }
 525                                 DBG("Relay viewer connection accepted socket %d", newsock->fd);
 526
 527                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR, &val,
 528                                                 sizeof(val));
 529                                 if (ret < 0) {
 530                                         PERROR("setsockopt inet");
 531                                         lttcomm_destroy_sock(newsock);
 532                                         connection_free(new_conn);
 533                                         goto error;
 534                                 }
 535                                 new_conn->sock = newsock;
 536
 537                                 /* Enqueue request for the dispatcher thread. */
 538                                 cds_wfcq_enqueue(&viewer_conn_queue.head, &viewer_conn_queue.tail,
 539                                                  &new_conn->qnode);
 540
 541                                 /*
 542                                  * Wake the dispatch queue futex. Implicit memory barrier with
 543                                  * the exchange in cds_wfcq_enqueue.
 544                                  */
 545                                 futex_nto1_wake(&viewer_conn_queue.futex);
 546                         }
 547                 }
 548         }
 549
 550 exit:
 551 error:
 552 error_poll_add:
 553 error_testpoint:
 554         lttng_poll_clean(&events);
 555 error_create_poll:
 556         if (live_control_sock->fd >= 0) {
 557                 ret = live_control_sock->ops->close(live_control_sock);
 558                 if (ret) {
 559                         PERROR("close");
 560                 }
 561         }
 562         lttcomm_destroy_sock(live_control_sock);
 563 error_sock_control:
 564         if (err) {
 565                 health_error();
 566                 DBG("Live viewer listener thread exited with error");
 567         }
 568         health_unregister(health_relayd);
 569         DBG("Live viewer listener thread cleanup complete");
 570         if (lttng_relay_stop_threads()) {
 571                 ERR("Error stopping threads");
 572         }
 573         return NULL;
 574 }
 575
 576 /*
 577  * This thread manages the dispatching of the requests to worker threads
 578  */
 579 static
 580 void *thread_dispatcher(void *data)
 581 {
 582         int err = -1;
 583         ssize_t ret;
 584         struct cds_wfcq_node *node;
 585         struct relay_connection *conn = NULL;
 586
 587         DBG("[thread] Live viewer relay dispatcher started");
 588
 589         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 590
 591         if (testpoint(relayd_thread_live_dispatcher)) {
 592                 goto error_testpoint;
 593         }
 594
 595         health_code_update();
 596
 597         while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 598                 health_code_update();
 599
 600                 /* Atomically prepare the queue futex */
 601                 futex_nto1_prepare(&viewer_conn_queue.futex);
 602
 603                 do {
 604                         health_code_update();
 605
 606                         /* Dequeue commands */
 607                         node = cds_wfcq_dequeue_blocking(&viewer_conn_queue.head,
 608                                                          &viewer_conn_queue.tail);
 609                         if (node == NULL) {
 610                                 DBG("Woken up but nothing in the live-viewer "
 611                                                 "relay command queue");
 612                                 /* Continue thread execution */
 613                                 break;
 614                         }
 615                         conn = caa_container_of(node, struct relay_connection, qnode);
 616                         DBG("Dispatching viewer request waiting on sock %d",
 617                                         conn->sock->fd);
 618
 619                         /*
 620                          * Inform worker thread of the new request. This call is blocking
 621                          * so we can be assured that the data will be read at some point in
 622                          * time or wait to the end of the world :)
 623                          */
 624                         ret = lttng_write(live_conn_pipe[1], &conn, sizeof(conn));
 625                         if (ret < 0) {
 626                                 PERROR("write conn pipe");
 627                                 connection_destroy(conn);
 628                                 goto error;
 629                         }
 630                 } while (node != NULL);
 631
 632                 /* Futex wait on queue. Blocking call on futex() */
 633                 health_poll_entry();
 634                 futex_nto1_wait(&viewer_conn_queue.futex);
 635                 health_poll_exit();
 636         }
 637
 638         /* Normal exit, no error */
 639         err = 0;
 640
 641 error:
 642 error_testpoint:
 643         if (err) {
 644                 health_error();
 645                 ERR("Health error occurred in %s", __func__);
 646         }
 647         health_unregister(health_relayd);
 648         DBG("Live viewer dispatch thread dying");
 649         if (lttng_relay_stop_threads()) {
 650                 ERR("Error stopping threads");
 651         }
 652         return NULL;
 653 }
 654
 655 /*
 656  * Establish connection with the viewer and check the versions.
 657  *
 658  * Return 0 on success or else negative value.
 659  */
 660 static
 661 int viewer_connect(struct relay_connection *conn)
 662 {
 663         int ret;
 664         struct lttng_viewer_connect reply, msg;
 665
 666         assert(conn);
 667
 668         conn->version_check_done = 1;
 669
 670         health_code_update();
 671
 672         DBG("Viewer is establishing a connection to the relayd.");
 673
 674         ret = recv_request(conn->sock, &msg, sizeof(msg));
 675         if (ret < 0) {
 676                 goto end;
 677         }
 678
 679         health_code_update();
 680
 681         memset(&reply, 0, sizeof(reply));
 682         reply.major = RELAYD_VERSION_COMM_MAJOR;
 683         reply.minor = RELAYD_VERSION_COMM_MINOR;
 684
 685         /* Major versions must be the same */
 686         if (reply.major != be32toh(msg.major)) {
 687                 DBG("Incompatible major versions ([relayd] %u vs [client] %u)",
 688                                 reply.major, be32toh(msg.major));
 689                 ret = -1;
 690                 goto end;
 691         }
 692
 693         conn->major = reply.major;
 694         /* We adapt to the lowest compatible version */
 695         if (reply.minor <= be32toh(msg.minor)) {
 696                 conn->minor = reply.minor;
 697         } else {
 698                 conn->minor = be32toh(msg.minor);
 699         }
 700
 701         if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_COMMAND) {
 702                 conn->type = RELAY_VIEWER_COMMAND;
 703         } else if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_NOTIFICATION) {
 704                 conn->type = RELAY_VIEWER_NOTIFICATION;
 705         } else {
 706                 ERR("Unknown connection type : %u", be32toh(msg.type));
 707                 ret = -1;
 708                 goto end;
 709         }
 710
 711         reply.major = htobe32(reply.major);
 712         reply.minor = htobe32(reply.minor);
 713         if (conn->type == RELAY_VIEWER_COMMAND) {
 714                 /*
 715                  * Increment outside of htobe64 macro, because can be used more than once
 716                  * within the macro, and thus the operation may be undefined.
 717                  */
 718                 last_relay_viewer_session_id++;
 719                 reply.viewer_session_id = htobe64(last_relay_viewer_session_id);
 720         }
 721
 722         health_code_update();
 723
 724         ret = send_response(conn->sock, &reply, sizeof(reply));
 725         if (ret < 0) {
 726                 goto end;
 727         }
 728
 729         health_code_update();
 730
 731         DBG("Version check done using protocol %u.%u", conn->major, conn->minor);
 732         ret = 0;
 733
 734 end:
 735         return ret;
 736 }
 737
 738 /*
 739  * Send the viewer the list of current sessions.
 740  *
 741  * Return 0 on success or else a negative value.
 742  */
 743 static
 744 int viewer_list_sessions(struct relay_connection *conn)
 745 {
 746         int ret;
 747         struct lttng_viewer_list_sessions session_list;
 748         unsigned long count;
 749         long approx_before, approx_after;
 750         struct lttng_ht_iter iter;
 751         struct lttng_viewer_session send_session;
 752         struct relay_session *session;
 753
 754         DBG("List sessions received");
 755
 756         rcu_read_lock();
 757         cds_lfht_count_nodes(conn->sessions_ht->ht, &approx_before, &count,
 758                         &approx_after);
 759         session_list.sessions_count = htobe32(count);
 760
 761         health_code_update();
 762
 763         ret = send_response(conn->sock, &session_list, sizeof(session_list));
 764         if (ret < 0) {
 765                 goto end_unlock;
 766         }
 767
 768         health_code_update();
 769
 770         cds_lfht_for_each_entry(conn->sessions_ht->ht, &iter.iter, session,
 771                         session_n.node) {
 772                 health_code_update();
 773
 774                 strncpy(send_session.session_name, session->session_name,
 775                                 sizeof(send_session.session_name));
 776                 strncpy(send_session.hostname, session->hostname,
 777                                 sizeof(send_session.hostname));
 778                 send_session.id = htobe64(session->id);
 779                 send_session.live_timer = htobe32(session->live_timer);
 780                 send_session.clients = htobe32(session->viewer_refcount);
 781                 send_session.streams = htobe32(session->stream_count);
 782
 783                 health_code_update();
 784
 785                 ret = send_response(conn->sock, &send_session, sizeof(send_session));
 786                 if (ret < 0) {
 787                         goto end_unlock;
 788                 }
 789         }
 790         health_code_update();
 791
 792         ret = 0;
 793 end_unlock:
 794         rcu_read_unlock();
 795         return ret;
 796 }
 797
 798 /*
 799  * Check if a connection is attached to a session.
 800  * Return 1 if attached, 0 if not attached, a negative value on error.
 801  */
 802 static
 803 int session_attached(struct relay_connection *conn, uint64_t session_id)
 804 {
 805         struct relay_session *session;
 806         int found = 0;
 807
 808         if (!conn->viewer_session) {
 809                 goto end;
 810         }
 811         cds_list_for_each_entry(session,
 812                         &conn->viewer_session->sessions_head,
 813                         viewer_session_list) {
 814                 if (session->id == session_id) {
 815                         found = 1;
 816                         goto end;
 817                 }
 818         }
 819
 820 end:
 821         return found;
 822 }
 823
 824 /*
 825  * Delete all streams for a specific session ID.
 826  */
 827 static void destroy_viewer_streams_by_session(struct relay_session *session)
 828 {
 829         struct relay_viewer_stream *stream;
 830         struct lttng_ht_iter iter;
 831
 832         assert(session);
 833
 834         rcu_read_lock();
 835         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, stream,
 836                         stream_n.node) {
 837                 struct ctf_trace *ctf_trace;
 838
 839                 health_code_update();
 840                 if (stream->session_id != session->id) {
 841                         continue;
 842                 }
 843
 844                 ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
 845                                 stream->path_name);
 846                 assert(ctf_trace);
 847
 848                 viewer_stream_delete(stream);
 849
 850                 if (stream->metadata_flag) {
 851                         ctf_trace->metadata_sent = 0;
 852                         ctf_trace->viewer_metadata_stream = NULL;
 853                 }
 854
 855                 viewer_stream_destroy(ctf_trace, stream);
 856         }
 857         rcu_read_unlock();
 858 }
 859
 860 static void try_destroy_streams(struct relay_session *session)
 861 {
 862         struct ctf_trace *ctf_trace;
 863         struct lttng_ht_iter iter;
 864
 865         assert(session);
 866
 867         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 868                         node.node) {
 869                 /* Attempt to destroy the ctf trace of that session. */
 870                 ctf_trace_try_destroy(session, ctf_trace);
 871         }
 872 }
 873
 874 /*
 875  * Cleanup a session.
 876  */
 877 static void cleanup_session(struct relay_connection *conn,
 878                 struct relay_session *session)
 879 {
 880         /*
 881          * Very important that this is done before destroying the session so we
 882          * can put back every viewer stream reference from the ctf_trace.
 883          */
 884         destroy_viewer_streams_by_session(session);
 885         try_destroy_streams(session);
 886         cds_list_del(&session->viewer_session_list);
 887         session_viewer_try_destroy(conn->sessions_ht, session);
 888 }
 889
 890 /*
 891  * Send the viewer the list of current sessions.
 892  */
 893 static
 894 int viewer_get_new_streams(struct relay_connection *conn)
 895 {
 896         int ret, send_streams = 0;
 897         uint32_t nb_created = 0, nb_unsent = 0, nb_streams = 0;
 898         struct lttng_viewer_new_streams_request request;
 899         struct lttng_viewer_new_streams_response response;
 900         struct relay_session *session;
 901         uint64_t session_id;
 902
 903         assert(conn);
 904
 905         DBG("Get new streams received");
 906
 907         health_code_update();
 908
 909         /* Receive the request from the connected client. */
 910         ret = recv_request(conn->sock, &request, sizeof(request));
 911         if (ret < 0) {
 912                 goto error;
 913         }
 914         session_id = be64toh(request.session_id);
 915
 916         health_code_update();
 917
 918         memset(&response, 0, sizeof(response));
 919
 920         rcu_read_lock();
 921         session = session_find_by_id(conn->sessions_ht, session_id);
 922         if (!session) {
 923                 DBG("Relay session %" PRIu64 " not found", session_id);
 924                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 925                 goto send_reply;
 926         }
 927
 928         if (!session_attached(conn, session_id)) {
 929                 send_streams = 0;
 930                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 931                 goto send_reply;
 932         }
 933
 934         send_streams = 1;
 935         response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 936
 937         ret = make_viewer_streams(session, LTTNG_VIEWER_SEEK_LAST, NULL, &nb_unsent,
 938                         &nb_created);
 939         if (ret < 0) {
 940                 goto end_unlock;
 941         }
 942         /* Only send back the newly created streams with the unsent ones. */
 943         nb_streams = nb_created + nb_unsent;
 944         response.streams_count = htobe32(nb_streams);
 945
 946         /*
 947          * If the session is closed and we have no new streams to send,
 948          * it means that the viewer has already received the whole trace
 949          * for this session and should now close it.
 950          */
 951         if (nb_streams == 0 && session->close_flag) {
 952                 send_streams = 0;
 953                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
 954                 /*
 955                  * Remove the session from the attached list of the connection
 956                  * and try to destroy it.
 957                  */
 958                 cds_list_del(&session->viewer_session_list);
 959                 cleanup_session(conn, session);
 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_unlock;
 968         }
 969         health_code_update();
 970
 971         /*
 972          * Unknown or empty session, just return gracefully, the viewer knows what
 973          * is happening.
 974          */
 975         if (!send_streams || !nb_streams) {
 976                 ret = 0;
 977                 goto end_unlock;
 978         }
 979
 980         /*
 981          * Send stream and *DON'T* ignore the sent flag so every viewer streams
 982          * that were not sent from that point will be sent to the viewer.
 983          */
 984         ret = send_viewer_streams(conn->sock, session, 0);
 985         if (ret < 0) {
 986                 goto end_unlock;
 987         }
 988
 989 end_unlock:
 990         rcu_read_unlock();
 991 error:
 992         return ret;
 993 }
 994
 995 /*
 996  * Send the viewer the list of current sessions.
 997  */
 998 static
 999 int viewer_attach_session(struct relay_connection *conn)
1000 {
1001         int send_streams = 0;
1002         ssize_t ret;
1003         uint32_t nb_streams = 0;
1004         enum lttng_viewer_seek seek_type;
1005         struct lttng_viewer_attach_session_request request;
1006         struct lttng_viewer_attach_session_response response;
1007         struct relay_session *session;
1008
1009         assert(conn);
1010
1011         health_code_update();
1012
1013         /* Receive the request from the connected client. */
1014         ret = recv_request(conn->sock, &request, sizeof(request));
1015         if (ret < 0) {
1016                 goto error;
1017         }
1018
1019         health_code_update();
1020
1021         memset(&response, 0, sizeof(response));
1022
1023         if (!conn->viewer_session) {
1024                 DBG("Client trying to attach before creating a live viewer session");
1025                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NO_SESSION);
1026                 goto send_reply;
1027         }
1028
1029         rcu_read_lock();
1030         session = session_find_by_id(conn->sessions_ht,
1031                         be64toh(request.session_id));
1032         if (!session) {
1033                 DBG("Relay session %" PRIu64 " not found",
1034                                 be64toh(request.session_id));
1035                 response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
1036                 goto send_reply;
1037         }
1038         session_viewer_attach(session);
1039         DBG("Attach session ID %" PRIu64 " received", be64toh(request.session_id));
1040
1041         if (uatomic_read(&session->viewer_refcount) > 1) {
1042                 DBG("Already a viewer attached");
1043                 response.status = htobe32(LTTNG_VIEWER_ATTACH_ALREADY);
1044                 session_viewer_detach(session);
1045                 goto send_reply;
1046         } else if (session->live_timer == 0) {
1047                 DBG("Not live session");
1048                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NOT_LIVE);
1049                 goto send_reply;
1050         } else {
1051                 send_streams = 1;
1052                 response.status = htobe32(LTTNG_VIEWER_ATTACH_OK);
1053                 cds_list_add(&session->viewer_session_list,
1054                                 &conn->viewer_session->sessions_head);
1055         }
1056
1057         switch (be32toh(request.seek)) {
1058         case LTTNG_VIEWER_SEEK_BEGINNING:
1059         case LTTNG_VIEWER_SEEK_LAST:
1060                 seek_type = be32toh(request.seek);
1061                 break;
1062         default:
1063                 ERR("Wrong seek parameter");
1064                 response.status = htobe32(LTTNG_VIEWER_ATTACH_SEEK_ERR);
1065                 send_streams = 0;
1066                 goto send_reply;
1067         }
1068
1069         ret = make_viewer_streams(session, seek_type, &nb_streams, NULL, NULL);
1070         if (ret < 0) {
1071                 goto end_unlock;
1072         }
1073         response.streams_count = htobe32(nb_streams);
1074
1075 send_reply:
1076         health_code_update();
1077         ret = send_response(conn->sock, &response, sizeof(response));
1078         if (ret < 0) {
1079                 goto end_unlock;
1080         }
1081         health_code_update();
1082
1083         /*
1084          * Unknown or empty session, just return gracefully, the viewer knows what
1085          * is happening.
1086          */
1087         if (!send_streams || !nb_streams) {
1088                 ret = 0;
1089                 goto end_unlock;
1090         }
1091
1092         /* Send stream and ignore the sent flag. */
1093         ret = send_viewer_streams(conn->sock, session, 1);
1094         if (ret < 0) {
1095                 goto end_unlock;
1096         }
1097
1098 end_unlock:
1099         rcu_read_unlock();
1100 error:
1101         return ret;
1102 }
1103
1104 /*
1105  * Open the index file if needed for the given vstream.
1106  *
1107  * If an index file is successfully opened, the index_read_fd of the stream is
1108  * set with it.
1109  *
1110  * Return 0 on success, a negative value on error (-ENOENT if not ready yet).
1111  */
1112 static int try_open_index(struct relay_viewer_stream *vstream,
1113                 struct relay_stream *rstream)
1114 {
1115         int ret = 0;
1116
1117         assert(vstream);
1118         assert(rstream);
1119
1120         if (vstream->index_read_fd >= 0) {
1121                 goto end;
1122         }
1123
1124         /*
1125          * First time, we open the index file and at least one index is ready.  The
1126          * race between the read and write of the total_index_received is
1127          * acceptable here since the client will be notified to simply come back
1128          * and get the next index.
1129          */
1130         if (rstream->total_index_received <= 0) {
1131                 ret = -ENOENT;
1132                 goto end;
1133         }
1134         ret = index_open(vstream->path_name, vstream->channel_name,
1135                         vstream->tracefile_count, vstream->tracefile_count_current);
1136         if (ret >= 0) {
1137                 vstream->index_read_fd = ret;
1138                 ret = 0;
1139                 goto end;
1140         }
1141
1142 end:
1143         return ret;
1144 }
1145
1146 /*
1147  * Check the status of the index for the given stream. This function updates
1148  * the index structure if needed and can destroy the vstream also for the HUP
1149  * situation.
1150  *
1151  * Return 0 means that we can proceed with the index. A value of 1 means that
1152  * the index has been updated and is ready to be send to the client. A negative
1153  * value indicates an error that can't be handled.
1154  */
1155 static int check_index_status(struct relay_viewer_stream *vstream,
1156                 struct relay_stream *rstream, struct ctf_trace *trace,
1157                 struct lttng_viewer_index *index)
1158 {
1159         int ret;
1160
1161         assert(vstream);
1162         assert(rstream);
1163         assert(index);
1164         assert(trace);
1165
1166         if (!rstream->close_flag) {
1167                 /* Rotate on abort (overwrite). */
1168                 if (vstream->abort_flag) {
1169                         DBG("Viewer stream %" PRIu64 " rotate because of overwrite",
1170                                         vstream->stream_handle);
1171                         ret = viewer_stream_rotate(vstream, rstream);
1172                         if (ret < 0) {
1173                                 goto error;
1174                         } else if (ret == 1) {
1175                                 /* EOF */
1176                                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1177                                 goto hup;
1178                         }
1179                         /* ret == 0 means successful so we continue. */
1180                 }
1181
1182                 /* Check if we are in the same trace file at this point. */
1183                 if (rstream->tracefile_count_current == vstream->tracefile_count_current) {
1184                         if (rstream->beacon_ts_end != -1ULL &&
1185                                         vstream->last_sent_index == rstream->total_index_received) {
1186                                 /*
1187                                  * We've received a synchronization beacon and the last index
1188                                  * available has been sent, the index for now is inactive.
1189                                  */
1190                                 index->status = htobe32(LTTNG_VIEWER_INDEX_INACTIVE);
1191                                 index->timestamp_end = htobe64(rstream->beacon_ts_end);
1192                                 index->stream_id = htobe64(rstream->ctf_stream_id);
1193                                 goto index_ready;
1194                         } else if (rstream->total_index_received <= vstream->last_sent_index
1195                                         && !vstream->close_write_flag) {
1196                                 /*
1197                                  * Reader and writer are working in the same tracefile, so we care
1198                                  * about the number of index received and sent. Otherwise, we read
1199                                  * up to EOF.
1200                                  */
1201                                 index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1202                                 goto index_ready;
1203                         }
1204                 }
1205                 /* Nothing to do with the index, continue with it. */
1206                 ret = 0;
1207         } else if (rstream->close_flag && vstream->close_write_flag &&
1208                         vstream->total_index_received == vstream->last_sent_index) {
1209                 /* Last index sent and current tracefile closed in write */
1210                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1211                 goto hup;
1212         } else {
1213                 vstream->close_write_flag = 1;
1214                 ret = 0;
1215         }
1216
1217 error:
1218         return ret;
1219
1220 hup:
1221         viewer_stream_delete(vstream);
1222         viewer_stream_destroy(trace, vstream);
1223 index_ready:
1224         return 1;
1225 }
1226
1227 /*
1228  * Send the next index for a stream.
1229  *
1230  * Return 0 on success or else a negative value.
1231  */
1232 static
1233 int viewer_get_next_index(struct relay_connection *conn)
1234 {
1235         int ret;
1236         ssize_t read_ret;
1237         struct lttng_viewer_get_next_index request_index;
1238         struct lttng_viewer_index viewer_index;
1239         struct ctf_packet_index packet_index;
1240         struct relay_viewer_stream *vstream;
1241         struct relay_stream *rstream;
1242         struct ctf_trace *ctf_trace;
1243         struct relay_session *session;
1244
1245         assert(conn);
1246
1247         DBG("Viewer get next index");
1248
1249         health_code_update();
1250
1251         ret = recv_request(conn->sock, &request_index, sizeof(request_index));
1252         if (ret < 0) {
1253                 goto end;
1254         }
1255         health_code_update();
1256
1257         rcu_read_lock();
1258         vstream = viewer_stream_find_by_id(be64toh(request_index.stream_id));
1259         if (!vstream) {
1260                 ret = -1;
1261                 goto end_unlock;
1262         }
1263
1264         session = session_find_by_id(conn->sessions_ht, vstream->session_id);
1265         if (!session) {
1266                 ret = -1;
1267                 goto end_unlock;
1268         }
1269
1270         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht, vstream->path_name);
1271         assert(ctf_trace);
1272
1273         memset(&viewer_index, 0, sizeof(viewer_index));
1274
1275         /*
1276          * The viewer should not ask for index on metadata stream.
1277          */
1278         if (vstream->metadata_flag) {
1279                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1280                 goto send_reply;
1281         }
1282
1283         rstream = stream_find_by_id(relay_streams_ht, vstream->stream_handle);
1284         assert(rstream);
1285
1286         /* Try to open an index if one is needed for that stream. */
1287         ret = try_open_index(vstream, rstream);
1288         if (ret < 0) {
1289                 if (ret == -ENOENT) {
1290                         /*
1291                          * The index is created only when the first data packet arrives, it
1292                          * might not be ready at the beginning of the session
1293                          */
1294                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1295                 } else {
1296                         /* Unhandled error. */
1297                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1298                 }
1299                 goto send_reply;
1300         }
1301
1302         pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1303         ret = check_index_status(vstream, rstream, ctf_trace, &viewer_index);
1304         pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1305         if (ret < 0) {
1306                 goto end_unlock;
1307         } else if (ret == 1) {
1308                 /*
1309                  * This means the viewer index data structure has been populated by the
1310                  * check call thus we now send back the reply to the client.
1311                  */
1312                 goto send_reply;
1313         }
1314         /* At this point, ret MUST be 0 thus we continue with the get. */
1315         assert(!ret);
1316
1317         if (!ctf_trace->metadata_received ||
1318                         ctf_trace->metadata_received > ctf_trace->metadata_sent) {
1319                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1320         }
1321
1322         ret = check_new_streams(conn);
1323         if (ret < 0) {
1324                 goto end_unlock;
1325         } else if (ret == 1) {
1326                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1327         }
1328
1329         pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1330         pthread_mutex_lock(&vstream->overwrite_lock);
1331         if (vstream->abort_flag) {
1332                 /* The file is being overwritten by the writer, we cannot use it. */
1333                 pthread_mutex_unlock(&vstream->overwrite_lock);
1334                 ret = viewer_stream_rotate(vstream, rstream);
1335                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1336                 if (ret < 0) {
1337                         goto end_unlock;
1338                 } else if (ret == 1) {
1339                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1340                         viewer_stream_delete(vstream);
1341                         viewer_stream_destroy(ctf_trace, vstream);
1342                 } else {
1343                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1344                 }
1345                 goto send_reply;
1346         }
1347
1348         read_ret = lttng_read(vstream->index_read_fd, &packet_index,
1349                         sizeof(packet_index));
1350         pthread_mutex_unlock(&vstream->overwrite_lock);
1351         pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1352         if (read_ret < 0) {
1353                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1354                 viewer_stream_delete(vstream);
1355                 viewer_stream_destroy(ctf_trace, vstream);
1356                 goto send_reply;
1357         } else if (read_ret < sizeof(packet_index)) {
1358                 pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1359                 if (vstream->close_write_flag) {
1360                         ret = viewer_stream_rotate(vstream, rstream);
1361                         if (ret < 0) {
1362                                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1363                                 goto end_unlock;
1364                         } else if (ret == 1) {
1365                                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1366                                 viewer_stream_delete(vstream);
1367                                 viewer_stream_destroy(ctf_trace, vstream);
1368                         } else {
1369                                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1370                         }
1371                 } else {
1372                         ERR("Relay reading index file %d", vstream->index_read_fd);
1373                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1374                 }
1375                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1376                 goto send_reply;
1377         } else {
1378                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_OK);
1379                 vstream->last_sent_index++;
1380         }
1381
1382         /*
1383          * Indexes are stored in big endian, no need to switch before sending.
1384          */
1385         viewer_index.offset = packet_index.offset;
1386         viewer_index.packet_size = packet_index.packet_size;
1387         viewer_index.content_size = packet_index.content_size;
1388         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1389         viewer_index.timestamp_end = packet_index.timestamp_end;
1390         viewer_index.events_discarded = packet_index.events_discarded;
1391         viewer_index.stream_id = packet_index.stream_id;
1392
1393 send_reply:
1394         viewer_index.flags = htobe32(viewer_index.flags);
1395         health_code_update();
1396
1397         ret = send_response(conn->sock, &viewer_index, sizeof(viewer_index));
1398         if (ret < 0) {
1399                 goto end_unlock;
1400         }
1401         health_code_update();
1402
1403         DBG("Index %" PRIu64 " for stream %" PRIu64 " sent",
1404                         vstream->last_sent_index, vstream->stream_handle);
1405
1406 end_unlock:
1407         rcu_read_unlock();
1408
1409 end:
1410         return ret;
1411 }
1412
1413 /*
1414  * Send the next index for a stream
1415  *
1416  * Return 0 on success or else a negative value.
1417  */
1418 static
1419 int viewer_get_packet(struct relay_connection *conn)
1420 {
1421         int ret, send_data = 0;
1422         char *data = NULL;
1423         uint32_t len = 0;
1424         ssize_t read_len;
1425         struct lttng_viewer_get_packet get_packet_info;
1426         struct lttng_viewer_trace_packet reply;
1427         struct relay_viewer_stream *stream;
1428         struct relay_session *session;
1429         struct ctf_trace *ctf_trace;
1430
1431         assert(conn);
1432
1433         DBG2("Relay get data packet");
1434
1435         health_code_update();
1436
1437         ret = recv_request(conn->sock, &get_packet_info, sizeof(get_packet_info));
1438         if (ret < 0) {
1439                 goto end;
1440         }
1441         health_code_update();
1442
1443         /* From this point on, the error label can be reached. */
1444         memset(&reply, 0, sizeof(reply));
1445
1446         rcu_read_lock();
1447         stream = viewer_stream_find_by_id(be64toh(get_packet_info.stream_id));
1448         if (!stream) {
1449                 goto error;
1450         }
1451
1452         session = session_find_by_id(conn->sessions_ht, stream->session_id);
1453         if (!session) {
1454                 ret = -1;
1455                 goto error;
1456         }
1457
1458         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
1459                         stream->path_name);
1460         assert(ctf_trace);
1461
1462         /*
1463          * First time we read this stream, we need open the tracefile, we should
1464          * only arrive here if an index has already been sent to the viewer, so the
1465          * tracefile must exist, if it does not it is a fatal error.
1466          */
1467         if (stream->read_fd < 0) {
1468                 char fullpath[PATH_MAX];
1469
1470                 if (stream->tracefile_count > 0) {
1471                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64, stream->path_name,
1472                                         stream->channel_name,
1473                                         stream->tracefile_count_current);
1474                 } else {
1475                         ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1476                                         stream->channel_name);
1477                 }
1478                 if (ret < 0) {
1479                         goto error;
1480                 }
1481                 ret = open(fullpath, O_RDONLY);
1482                 if (ret < 0) {
1483                         PERROR("Relay opening trace file");
1484                         goto error;
1485                 }
1486                 stream->read_fd = ret;
1487         }
1488
1489         if (!ctf_trace->metadata_received ||
1490                         ctf_trace->metadata_received > ctf_trace->metadata_sent) {
1491                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1492                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1493                 goto send_reply;
1494         }
1495
1496         ret = check_new_streams(conn);
1497         if (ret < 0) {
1498                 goto end_unlock;
1499         } else if (ret == 1) {
1500                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1501                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1502                 goto send_reply;
1503         }
1504
1505         len = be32toh(get_packet_info.len);
1506         data = zmalloc(len);
1507         if (!data) {
1508                 PERROR("relay data zmalloc");
1509                 goto error;
1510         }
1511
1512         ret = lseek(stream->read_fd, be64toh(get_packet_info.offset), SEEK_SET);
1513         if (ret < 0) {
1514                 /*
1515                  * If the read fd was closed by the streaming side, the
1516                  * abort_flag will be set to 1, otherwise it is an error.
1517                  */
1518                 if (stream->abort_flag == 0) {
1519                         PERROR("lseek");
1520                         goto error;
1521                 }
1522                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_EOF);
1523                 goto send_reply;
1524         }
1525         read_len = lttng_read(stream->read_fd, data, len);
1526         if (read_len < len) {
1527                 /*
1528                  * If the read fd was closed by the streaming side, the
1529                  * abort_flag will be set to 1, otherwise it is an error.
1530                  */
1531                 if (stream->abort_flag == 0) {
1532                         PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1533                                         stream->read_fd,
1534                                         be64toh(get_packet_info.offset));
1535                         goto error;
1536                 } else {
1537                         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_EOF);
1538                         goto send_reply;
1539                 }
1540         }
1541         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_OK);
1542         reply.len = htobe32(len);
1543         send_data = 1;
1544         goto send_reply;
1545
1546 error:
1547         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1548
1549 send_reply:
1550         reply.flags = htobe32(reply.flags);
1551
1552         health_code_update();
1553
1554         ret = send_response(conn->sock, &reply, sizeof(reply));
1555         if (ret < 0) {
1556                 goto end_unlock;
1557         }
1558         health_code_update();
1559
1560         if (send_data) {
1561                 health_code_update();
1562                 ret = send_response(conn->sock, data, len);
1563                 if (ret < 0) {
1564                         goto end_unlock;
1565                 }
1566                 health_code_update();
1567         }
1568
1569         DBG("Sent %u bytes for stream %" PRIu64, len,
1570                         be64toh(get_packet_info.stream_id));
1571
1572 end_unlock:
1573         free(data);
1574         rcu_read_unlock();
1575
1576 end:
1577         return ret;
1578 }
1579
1580 /*
1581  * Send the session's metadata
1582  *
1583  * Return 0 on success else a negative value.
1584  */
1585 static
1586 int viewer_get_metadata(struct relay_connection *conn)
1587 {
1588         int ret = 0;
1589         ssize_t read_len;
1590         uint64_t len = 0;
1591         char *data = NULL;
1592         struct lttng_viewer_get_metadata request;
1593         struct lttng_viewer_metadata_packet reply;
1594         struct relay_viewer_stream *stream;
1595         struct ctf_trace *ctf_trace;
1596         struct relay_session *session;
1597
1598         assert(conn);
1599
1600         DBG("Relay get metadata");
1601
1602         health_code_update();
1603
1604         ret = recv_request(conn->sock, &request, sizeof(request));
1605         if (ret < 0) {
1606                 goto end;
1607         }
1608         health_code_update();
1609
1610         memset(&reply, 0, sizeof(reply));
1611
1612         rcu_read_lock();
1613         stream = viewer_stream_find_by_id(be64toh(request.stream_id));
1614         if (!stream || !stream->metadata_flag) {
1615                 ERR("Invalid metadata stream");
1616                 goto error;
1617         }
1618
1619         session = session_find_by_id(conn->sessions_ht, stream->session_id);
1620         if (!session) {
1621                 ret = -1;
1622                 goto error;
1623         }
1624
1625         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
1626                         stream->path_name);
1627         assert(ctf_trace);
1628         assert(ctf_trace->metadata_sent <= ctf_trace->metadata_received);
1629
1630         len = ctf_trace->metadata_received - ctf_trace->metadata_sent;
1631         if (len == 0) {
1632                 reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
1633                 goto send_reply;
1634         }
1635
1636         /* first time, we open the metadata file */
1637         if (stream->read_fd < 0) {
1638                 char fullpath[PATH_MAX];
1639
1640                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1641                                 stream->channel_name);
1642                 if (ret < 0) {
1643                         goto error;
1644                 }
1645                 ret = open(fullpath, O_RDONLY);
1646                 if (ret < 0) {
1647                         PERROR("Relay opening metadata file");
1648                         goto error;
1649                 }
1650                 stream->read_fd = ret;
1651         }
1652
1653         reply.len = htobe64(len);
1654         data = zmalloc(len);
1655         if (!data) {
1656                 PERROR("viewer metadata zmalloc");
1657                 goto error;
1658         }
1659
1660         read_len = lttng_read(stream->read_fd, data, len);
1661         if (read_len < len) {
1662                 PERROR("Relay reading metadata file");
1663                 goto error;
1664         }
1665         ctf_trace->metadata_sent += read_len;
1666         reply.status = htobe32(LTTNG_VIEWER_METADATA_OK);
1667         goto send_reply;
1668
1669 error:
1670         reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1671
1672 send_reply:
1673         health_code_update();
1674         ret = send_response(conn->sock, &reply, sizeof(reply));
1675         if (ret < 0) {
1676                 goto end_unlock;
1677         }
1678         health_code_update();
1679
1680         if (len > 0) {
1681                 ret = send_response(conn->sock, data, len);
1682                 if (ret < 0) {
1683                         goto end_unlock;
1684                 }
1685         }
1686
1687         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1688                         be64toh(request.stream_id));
1689
1690         DBG("Metadata sent");
1691
1692 end_unlock:
1693         free(data);
1694         rcu_read_unlock();
1695 end:
1696         return ret;
1697 }
1698
1699 /*
1700  * Create a viewer session.
1701  *
1702  * Return 0 on success or else a negative value.
1703  */
1704 static
1705 int viewer_create_session(struct relay_connection *conn)
1706 {
1707         int ret;
1708         struct lttng_viewer_create_session_response resp;
1709
1710         DBG("Viewer create session received");
1711
1712         memset(&resp, 0, sizeof(resp));
1713         resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_OK);
1714         conn->viewer_session = zmalloc(sizeof(*conn->viewer_session));
1715         if (!conn->viewer_session) {
1716                 ERR("Allocation viewer session");
1717                 resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_ERR);
1718                 goto send_reply;
1719         }
1720         CDS_INIT_LIST_HEAD(&conn->viewer_session->sessions_head);
1721
1722 send_reply:
1723         health_code_update();
1724         ret = send_response(conn->sock, &resp, sizeof(resp));
1725         if (ret < 0) {
1726                 goto end;
1727         }
1728         health_code_update();
1729         ret = 0;
1730
1731 end:
1732         return ret;
1733 }
1734
1735
1736 /*
1737  * live_relay_unknown_command: send -1 if received unknown command
1738  */
1739 static
1740 void live_relay_unknown_command(struct relay_connection *conn)
1741 {
1742         struct lttcomm_relayd_generic_reply reply;
1743
1744         memset(&reply, 0, sizeof(reply));
1745         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1746         (void) send_response(conn->sock, &reply, sizeof(reply));
1747 }
1748
1749 /*
1750  * Process the commands received on the control socket
1751  */
1752 static
1753 int process_control(struct lttng_viewer_cmd *recv_hdr,
1754                 struct relay_connection *conn)
1755 {
1756         int ret = 0;
1757         uint32_t msg_value;
1758
1759         assert(recv_hdr);
1760         assert(conn);
1761
1762         msg_value = be32toh(recv_hdr->cmd);
1763
1764         /*
1765          * Make sure we've done the version check before any command other then a
1766          * new client connection.
1767          */
1768         if (msg_value != LTTNG_VIEWER_CONNECT && !conn->version_check_done) {
1769                 ERR("Viewer conn value %" PRIu32 " before version check", msg_value);
1770                 ret = -1;
1771                 goto end;
1772         }
1773
1774         switch (msg_value) {
1775         case LTTNG_VIEWER_CONNECT:
1776                 ret = viewer_connect(conn);
1777                 break;
1778         case LTTNG_VIEWER_LIST_SESSIONS:
1779                 ret = viewer_list_sessions(conn);
1780                 break;
1781         case LTTNG_VIEWER_ATTACH_SESSION:
1782                 ret = viewer_attach_session(conn);
1783                 break;
1784         case LTTNG_VIEWER_GET_NEXT_INDEX:
1785                 ret = viewer_get_next_index(conn);
1786                 break;
1787         case LTTNG_VIEWER_GET_PACKET:
1788                 ret = viewer_get_packet(conn);
1789                 break;
1790         case LTTNG_VIEWER_GET_METADATA:
1791                 ret = viewer_get_metadata(conn);
1792                 break;
1793         case LTTNG_VIEWER_GET_NEW_STREAMS:
1794                 ret = viewer_get_new_streams(conn);
1795                 break;
1796         case LTTNG_VIEWER_CREATE_SESSION:
1797                 ret = viewer_create_session(conn);
1798                 break;
1799         default:
1800                 ERR("Received unknown viewer command (%u)", be32toh(recv_hdr->cmd));
1801                 live_relay_unknown_command(conn);
1802                 ret = -1;
1803                 goto end;
1804         }
1805
1806 end:
1807         return ret;
1808 }
1809
1810 static
1811 void cleanup_connection_pollfd(struct lttng_poll_event *events, int pollfd)
1812 {
1813         int ret;
1814
1815         assert(events);
1816
1817         (void) lttng_poll_del(events, pollfd);
1818
1819         ret = close(pollfd);
1820         if (ret < 0) {
1821                 ERR("Closing pollfd %d", pollfd);
1822         }
1823 }
1824
1825 /*
1826  * Delete and destroy a connection.
1827  *
1828  * RCU read side lock MUST be acquired.
1829  */
1830 static void destroy_connection(struct lttng_ht *relay_connections_ht,
1831                 struct relay_connection *conn)
1832 {
1833         struct relay_session *session, *tmp_session;
1834
1835         assert(relay_connections_ht);
1836         assert(conn);
1837
1838         connection_delete(relay_connections_ht, conn);
1839
1840         if (!conn->viewer_session) {
1841                 goto end;
1842         }
1843
1844         rcu_read_lock();
1845         cds_list_for_each_entry_safe(session, tmp_session,
1846                         &conn->viewer_session->sessions_head,
1847                         viewer_session_list) {
1848                 DBG("Cleaning connection of session ID %" PRIu64, session->id);
1849                 cleanup_session(conn, session);
1850         }
1851         rcu_read_unlock();
1852
1853 end:
1854         connection_destroy(conn);
1855 }
1856
1857 /*
1858  * This thread does the actual work
1859  */
1860 static
1861 void *thread_worker(void *data)
1862 {
1863         int ret, err = -1;
1864         uint32_t nb_fd;
1865         struct relay_connection *conn;
1866         struct lttng_poll_event events;
1867         struct lttng_ht *relay_connections_ht;
1868         struct lttng_ht_iter iter;
1869         struct lttng_viewer_cmd recv_hdr;
1870         struct relay_local_data *relay_ctx = (struct relay_local_data *) data;
1871         struct lttng_ht *sessions_ht = relay_ctx->sessions_ht;
1872
1873         DBG("[thread] Live viewer relay worker started");
1874
1875         rcu_register_thread();
1876
1877         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1878
1879         if (testpoint(relayd_thread_live_worker)) {
1880                 goto error_testpoint;
1881         }
1882
1883         /* table of connections indexed on socket */
1884         relay_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1885         if (!relay_connections_ht) {
1886                 goto relay_connections_ht_error;
1887         }
1888
1889         ret = create_thread_poll_set(&events, 2);
1890         if (ret < 0) {
1891                 goto error_poll_create;
1892         }
1893
1894         ret = lttng_poll_add(&events, live_conn_pipe[0], LPOLLIN | LPOLLRDHUP);
1895         if (ret < 0) {
1896                 goto error;
1897         }
1898
1899 restart:
1900         while (1) {
1901                 int i;
1902
1903                 health_code_update();
1904
1905                 /* Infinite blocking call, waiting for transmission */
1906                 DBG3("Relayd live viewer worker thread polling...");
1907                 health_poll_entry();
1908                 ret = lttng_poll_wait(&events, -1);
1909                 health_poll_exit();
1910                 if (ret < 0) {
1911                         /*
1912                          * Restart interrupted system call.
1913                          */
1914                         if (errno == EINTR) {
1915                                 goto restart;
1916                         }
1917                         goto error;
1918                 }
1919
1920                 nb_fd = ret;
1921
1922                 /*
1923                  * Process control. The control connection is prioritised so we don't
1924                  * starve it with high throughput tracing data on the data
1925                  * connection.
1926                  */
1927                 for (i = 0; i < nb_fd; i++) {
1928                         /* Fetch once the poll data */
1929                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1930                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1931
1932                         health_code_update();
1933
1934                         if (!revents) {
1935                                 /* No activity for this FD (poll implementation). */
1936                                 continue;
1937                         }
1938
1939                         /* Thread quit pipe has been closed. Killing thread. */
1940                         ret = check_thread_quit_pipe(pollfd, revents);
1941                         if (ret) {
1942                                 err = 0;
1943                                 goto exit;
1944                         }
1945
1946                         /* Inspect the relay conn pipe for new connection */
1947                         if (pollfd == live_conn_pipe[0]) {
1948                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1949                                         ERR("Relay live pipe error");
1950                                         goto error;
1951                                 } else if (revents & LPOLLIN) {
1952                                         ret = lttng_read(live_conn_pipe[0], &conn, sizeof(conn));
1953                                         if (ret < 0) {
1954                                                 goto error;
1955                                         }
1956                                         conn->sessions_ht = sessions_ht;
1957                                         connection_init(conn);
1958                                         lttng_poll_add(&events, conn->sock->fd,
1959                                                         LPOLLIN | LPOLLRDHUP);
1960                                         rcu_read_lock();
1961                                         lttng_ht_add_unique_ulong(relay_connections_ht,
1962                                                         &conn->sock_n);
1963                                         rcu_read_unlock();
1964                                         DBG("Connection socket %d added", conn->sock->fd);
1965                                 }
1966                         } else {
1967                                 rcu_read_lock();
1968                                 conn = connection_find_by_sock(relay_connections_ht, pollfd);
1969                                 /* If not found, there is a synchronization issue. */
1970                                 assert(conn);
1971
1972                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1973                                         cleanup_connection_pollfd(&events, pollfd);
1974                                         destroy_connection(relay_connections_ht, conn);
1975                                 } else if (revents & LPOLLIN) {
1976                                         ret = conn->sock->ops->recvmsg(conn->sock, &recv_hdr,
1977                                                         sizeof(recv_hdr), 0);
1978                                         if (ret <= 0) {
1979                                                 /* Connection closed */
1980                                                 cleanup_connection_pollfd(&events, pollfd);
1981                                                 destroy_connection(relay_connections_ht, conn);
1982                                                 DBG("Viewer control conn closed with %d", pollfd);
1983                                         } else {
1984                                                 ret = process_control(&recv_hdr, conn);
1985                                                 if (ret < 0) {
1986                                                         /* Clear the session on error. */
1987                                                         cleanup_connection_pollfd(&events, pollfd);
1988                                                         destroy_connection(relay_connections_ht, conn);
1989                                                         DBG("Viewer connection closed with %d", pollfd);
1990                                                 }
1991                                         }
1992                                 }
1993                                 rcu_read_unlock();
1994                         }
1995                 }
1996         }
1997
1998 exit:
1999 error:
2000         lttng_poll_clean(&events);
2001
2002         /* Cleanup reamaining connection object. */
2003         rcu_read_lock();
2004         cds_lfht_for_each_entry(relay_connections_ht->ht, &iter.iter, conn,
2005                         sock_n.node) {
2006                 health_code_update();
2007                 destroy_connection(relay_connections_ht, conn);
2008         }
2009         rcu_read_unlock();
2010 error_poll_create:
2011         lttng_ht_destroy(relay_connections_ht);
2012 relay_connections_ht_error:
2013         /* Close relay conn pipes */
2014         utils_close_pipe(live_conn_pipe);
2015         if (err) {
2016                 DBG("Viewer worker thread exited with error");
2017         }
2018         DBG("Viewer worker thread cleanup complete");
2019 error_testpoint:
2020         if (err) {
2021                 health_error();
2022                 ERR("Health error occurred in %s", __func__);
2023         }
2024         health_unregister(health_relayd);
2025         if (lttng_relay_stop_threads()) {
2026                 ERR("Error stopping threads");
2027         }
2028         rcu_unregister_thread();
2029         return NULL;
2030 }
2031
2032 /*
2033  * Create the relay command pipe to wake thread_manage_apps.
2034  * Closed in cleanup().
2035  */
2036 static int create_conn_pipe(void)
2037 {
2038         return utils_create_pipe_cloexec(live_conn_pipe);
2039 }
2040
2041 int relayd_live_join(void)
2042 {
2043         int ret, retval = 0;
2044         void *status;
2045
2046         ret = pthread_join(live_listener_thread, &status);
2047         if (ret) {
2048                 errno = ret;
2049                 PERROR("pthread_join live listener");
2050                 retval = -1;
2051         }
2052
2053         ret = pthread_join(live_worker_thread, &status);
2054         if (ret) {
2055                 errno = ret;
2056                 PERROR("pthread_join live worker");
2057                 retval = -1;
2058         }
2059
2060         ret = pthread_join(live_dispatcher_thread, &status);
2061         if (ret) {
2062                 errno = ret;
2063                 PERROR("pthread_join live dispatcher");
2064                 retval = -1;
2065         }
2066
2067         cleanup_relayd_live();
2068
2069         return retval;
2070 }
2071
2072 /*
2073  * main
2074  */
2075 int relayd_live_create(struct lttng_uri *uri,
2076                 struct relay_local_data *relay_ctx)
2077 {
2078         int ret = 0, retval = 0;
2079         void *status;
2080         int is_root;
2081
2082         if (!uri) {
2083                 retval = -1;
2084                 goto exit_init_data;
2085         }
2086         live_uri = uri;
2087
2088         /* Check if daemon is UID = 0 */
2089         is_root = !getuid();
2090
2091         if (!is_root) {
2092                 if (live_uri->port < 1024) {
2093                         ERR("Need to be root to use ports < 1024");
2094                         retval = -1;
2095                         goto exit_init_data;
2096                 }
2097         }
2098
2099         /* Setup the thread apps communication pipe. */
2100         if (create_conn_pipe()) {
2101                 retval = -1;
2102                 goto exit_init_data;
2103         }
2104
2105         /* Init relay command queue. */
2106         cds_wfcq_init(&viewer_conn_queue.head, &viewer_conn_queue.tail);
2107
2108         /* Set up max poll set size */
2109         lttng_poll_set_max_size();
2110
2111         /* Setup the dispatcher thread */
2112         ret = pthread_create(&live_dispatcher_thread, NULL,
2113                         thread_dispatcher, (void *) NULL);
2114         if (ret) {
2115                 errno = ret;
2116                 PERROR("pthread_create viewer dispatcher");
2117                 retval = -1;
2118                 goto exit_dispatcher_thread;
2119         }
2120
2121         /* Setup the worker thread */
2122         ret = pthread_create(&live_worker_thread, NULL,
2123                         thread_worker, relay_ctx);
2124         if (ret) {
2125                 errno = ret;
2126                 PERROR("pthread_create viewer worker");
2127                 retval = -1;
2128                 goto exit_worker_thread;
2129         }
2130
2131         /* Setup the listener thread */
2132         ret = pthread_create(&live_listener_thread, NULL,
2133                         thread_listener, (void *) NULL);
2134         if (ret) {
2135                 errno = ret;
2136                 PERROR("pthread_create viewer listener");
2137                 retval = -1;
2138                 goto exit_listener_thread;
2139         }
2140
2141         /*
2142          * All OK, started all threads.
2143          */
2144         return retval;
2145
2146
2147         ret = pthread_join(live_listener_thread, &status);
2148         if (ret) {
2149                 errno = ret;
2150                 PERROR("pthread_join live listener");
2151                 retval = -1;
2152         }
2153 exit_listener_thread:
2154
2155         ret = pthread_join(live_worker_thread, &status);
2156         if (ret) {
2157                 errno = ret;
2158                 PERROR("pthread_join live worker");
2159                 retval = -1;
2160         }
2161 exit_worker_thread:
2162
2163         ret = pthread_join(live_dispatcher_thread, &status);
2164         if (ret) {
2165                 errno = ret;
2166                 PERROR("pthread_join live dispatcher");
2167                 retval = -1;
2168         }
2169 exit_dispatcher_thread:
2170
2171 exit_init_data:
2172         cleanup_relayd_live();
2173
2174         return retval;
2175 }