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 #define _LGPL_SOURCE
  21 #include <getopt.h>
  22 #include <grp.h>
  23 #include <limits.h>
  24 #include <pthread.h>
  25 #include <signal.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <sys/mman.h>
  30 #include <sys/mount.h>
  31 #include <sys/resource.h>
  32 #include <sys/socket.h>
  33 #include <sys/stat.h>
  34 #include <sys/types.h>
  35 #include <sys/wait.h>
  36 #include <inttypes.h>
  37 #include <urcu/futex.h>
  38 #include <urcu/uatomic.h>
  39 #include <unistd.h>
  40 #include <fcntl.h>
  41 #include <config.h>
  42
  43 #include <lttng/lttng.h>
  44 #include <common/common.h>
  45 #include <common/compat/poll.h>
  46 #include <common/compat/socket.h>
  47 #include <common/compat/endian.h>
  48 #include <common/defaults.h>
  49 #include <common/futex.h>
  50 #include <common/index/index.h>
  51 #include <common/sessiond-comm/sessiond-comm.h>
  52 #include <common/sessiond-comm/inet.h>
  53 #include <common/sessiond-comm/relayd.h>
  54 #include <common/uri.h>
  55 #include <common/utils.h>
  56
  57 #include "cmd.h"
  58 #include "live.h"
  59 #include "lttng-relayd.h"
  60 #include "utils.h"
  61 #include "health-relayd.h"
  62 #include "testpoint.h"
  63 #include "viewer-stream.h"
  64 #include "stream.h"
  65 #include "session.h"
  66 #include "ctf-trace.h"
  67 #include "connection.h"
  68
  69 static struct lttng_uri *live_uri;
  70
  71 /*
  72  * This pipe is used to inform the worker thread that a command is queued and
  73  * ready to be processed.
  74  */
  75 static int live_conn_pipe[2] = { -1, -1 };
  76
  77 /* Shared between threads */
  78 static int live_dispatch_thread_exit;
  79
  80 static pthread_t live_listener_thread;
  81 static pthread_t live_dispatcher_thread;
  82 static pthread_t live_worker_thread;
  83
  84 /*
  85  * Relay command queue.
  86  *
  87  * The live_thread_listener and live_thread_dispatcher communicate with this
  88  * queue.
  89  */
  90 static struct relay_conn_queue viewer_conn_queue;
  91
  92 static uint64_t last_relay_viewer_session_id;
  93
  94 /*
  95  * Cleanup the daemon
  96  */
  97 static
  98 void cleanup_relayd_live(void)
  99 {
 100         DBG("Cleaning up");
 101
 102         free(live_uri);
 103 }
 104
 105 /*
 106  * Receive a request buffer using a given socket, destination allocated buffer
 107  * of length size.
 108  *
 109  * Return the size of the received message or else a negative value on error
 110  * with errno being set by recvmsg() syscall.
 111  */
 112 static
 113 ssize_t recv_request(struct lttcomm_sock *sock, void *buf, size_t size)
 114 {
 115         ssize_t ret;
 116
 117         assert(sock);
 118         assert(buf);
 119
 120         ret = sock->ops->recvmsg(sock, buf, size, 0);
 121         if (ret < 0 || ret != size) {
 122                 if (ret == 0) {
 123                         /* Orderly shutdown. Not necessary to print an error. */
 124                         DBG("Socket %d did an orderly shutdown", sock->fd);
 125                 } else {
 126                         ERR("Relay failed to receive request.");
 127                 }
 128                 ret = -1;
 129         }
 130
 131         return ret;
 132 }
 133
 134 /*
 135  * Send a response buffer using a given socket, source allocated buffer of
 136  * length size.
 137  *
 138  * Return the size of the sent message or else a negative value on error with
 139  * errno being set by sendmsg() syscall.
 140  */
 141 static
 142 ssize_t send_response(struct lttcomm_sock *sock, void *buf, size_t size)
 143 {
 144         ssize_t ret;
 145
 146         assert(sock);
 147         assert(buf);
 148
 149         ret = sock->ops->sendmsg(sock, buf, size, 0);
 150         if (ret < 0) {
 151                 ERR("Relayd failed to send response.");
 152         }
 153
 154         return ret;
 155 }
 156
 157 /*
 158  * Atomically check if new streams got added in one of the sessions attached
 159  * and reset the flag to 0.
 160  *
 161  * Returns 1 if new streams got added, 0 if nothing changed, a negative value
 162  * on error.
 163  */
 164 static
 165 int check_new_streams(struct relay_connection *conn)
 166 {
 167         struct relay_session *session;
 168         unsigned long current_val;
 169         int ret = 0;
 170
 171         if (!conn->viewer_session) {
 172                 goto end;
 173         }
 174         cds_list_for_each_entry(session,
 175                         &conn->viewer_session->sessions_head,
 176                         viewer_session_list) {
 177                 current_val = uatomic_cmpxchg(&session->new_streams, 1, 0);
 178                 ret = current_val;
 179                 if (ret == 1) {
 180                         goto end;
 181                 }
 182         }
 183
 184 end:
 185         return ret;
 186 }
 187
 188 /*
 189  * Send viewer streams to the given socket. The ignore_sent_flag indicates if
 190  * this function should ignore the sent flag or not.
 191  *
 192  * Return 0 on success or else a negative value.
 193  */
 194 static
 195 ssize_t send_viewer_streams(struct lttcomm_sock *sock,
 196                 struct relay_session *session, unsigned int ignore_sent_flag)
 197 {
 198         ssize_t ret;
 199         struct lttng_viewer_stream send_stream;
 200         struct lttng_ht_iter iter;
 201         struct relay_viewer_stream *vstream;
 202
 203         assert(session);
 204
 205         rcu_read_lock();
 206
 207         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
 208                         stream_n.node) {
 209                 struct ctf_trace *ctf_trace;
 210
 211                 health_code_update();
 212
 213                 /* Ignore if not the same session. */
 214                 if (vstream->session_id != session->id ||
 215                                 (!ignore_sent_flag && vstream->sent_flag)) {
 216                         continue;
 217                 }
 218
 219                 ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
 220                                 vstream->path_name);
 221                 assert(ctf_trace);
 222
 223                 send_stream.id = htobe64(vstream->stream_handle);
 224                 send_stream.ctf_trace_id = htobe64(ctf_trace->id);
 225                 send_stream.metadata_flag = htobe32(vstream->metadata_flag);
 226                 strncpy(send_stream.path_name, vstream->path_name,
 227                                 sizeof(send_stream.path_name));
 228                 strncpy(send_stream.channel_name, vstream->channel_name,
 229                                 sizeof(send_stream.channel_name));
 230
 231                 DBG("Sending stream %" PRIu64 " to viewer", vstream->stream_handle);
 232                 ret = send_response(sock, &send_stream, sizeof(send_stream));
 233                 if (ret < 0) {
 234                         goto end_unlock;
 235                 }
 236                 vstream->sent_flag = 1;
 237         }
 238
 239         ret = 0;
 240
 241 end_unlock:
 242         rcu_read_unlock();
 243         return ret;
 244 }
 245
 246 /*
 247  * Create every viewer stream possible for the given session with the seek
 248  * type. Three counters *can* be return which are in order the total amount of
 249  * viewer stream of the session, the number of unsent stream and the number of
 250  * stream created. Those counters can be NULL and thus will be ignored.
 251  *
 252  * Return 0 on success or else a negative value.
 253  */
 254 static
 255 int make_viewer_streams(struct relay_session *session,
 256                 enum lttng_viewer_seek seek_t, uint32_t *nb_total, uint32_t *nb_unsent,
 257                 uint32_t *nb_created)
 258 {
 259         int ret;
 260         struct lttng_ht_iter iter;
 261         struct ctf_trace *ctf_trace;
 262
 263         assert(session);
 264
 265         /*
 266          * This is to make sure we create viewer streams for a full received
 267          * channel. For instance, if we have 8 streams for a channel that are
 268          * concurrently being flagged ready, we can end up creating just a subset
 269          * of the 8 streams (the ones that are flagged). This lock avoids this
 270          * limbo state.
 271          */
 272         pthread_mutex_lock(&session->viewer_ready_lock);
 273
 274         /*
 275          * Create viewer streams for relay streams that are ready to be used for a
 276          * the given session id only.
 277          */
 278         rcu_read_lock();
 279         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 280                         node.node) {
 281                 struct relay_stream *stream;
 282
 283                 health_code_update();
 284
 285                 if (ctf_trace->invalid_flag) {
 286                         continue;
 287                 }
 288
 289                 cds_list_for_each_entry(stream, &ctf_trace->stream_list, trace_list) {
 290                         struct relay_viewer_stream *vstream;
 291
 292                         if (!stream->viewer_ready) {
 293                                 continue;
 294                         }
 295
 296                         vstream = viewer_stream_find_by_id(stream->stream_handle);
 297                         if (!vstream) {
 298                                 vstream = viewer_stream_create(stream, seek_t, ctf_trace);
 299                                 if (!vstream) {
 300                                         ret = -1;
 301                                         goto error_unlock;
 302                                 }
 303                                 /* Acquire reference to ctf_trace. */
 304                                 ctf_trace_get_ref(ctf_trace);
 305
 306                                 if (nb_created) {
 307                                         /* Update number of created stream counter. */
 308                                         (*nb_created)++;
 309                                 }
 310                         } else if (!vstream->sent_flag && nb_unsent) {
 311                                 /* Update number of unsent stream counter. */
 312                                 (*nb_unsent)++;
 313                         }
 314                         /* Update number of total stream counter. */
 315                         if (nb_total) {
 316                                 (*nb_total)++;
 317                         }
 318                 }
 319         }
 320
 321         ret = 0;
 322
 323 error_unlock:
 324         rcu_read_unlock();
 325         pthread_mutex_unlock(&session->viewer_ready_lock);
 326         return ret;
 327 }
 328
 329 int relayd_live_stop(void)
 330 {
 331         /* Stop dispatch thread */
 332         CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
 333         futex_nto1_wake(&viewer_conn_queue.futex);
 334         return 0;
 335 }
 336
 337 /*
 338  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 339  */
 340 static
 341 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 342 {
 343         int ret;
 344
 345         if (events == NULL || size == 0) {
 346                 ret = -1;
 347                 goto error;
 348         }
 349
 350         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 351         if (ret < 0) {
 352                 goto error;
 353         }
 354
 355         /* Add quit pipe */
 356         ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
 357         if (ret < 0) {
 358                 goto error;
 359         }
 360
 361         return 0;
 362
 363 error:
 364         return ret;
 365 }
 366
 367 /*
 368  * Check if the thread quit pipe was triggered.
 369  *
 370  * Return 1 if it was triggered else 0;
 371  */
 372 static
 373 int check_thread_quit_pipe(int fd, uint32_t events)
 374 {
 375         if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
 376                 return 1;
 377         }
 378
 379         return 0;
 380 }
 381
 382 /*
 383  * Create and init socket from uri.
 384  */
 385 static
 386 struct lttcomm_sock *init_socket(struct lttng_uri *uri)
 387 {
 388         int ret;
 389         struct lttcomm_sock *sock = NULL;
 390
 391         sock = lttcomm_alloc_sock_from_uri(uri);
 392         if (sock == NULL) {
 393                 ERR("Allocating socket");
 394                 goto error;
 395         }
 396
 397         ret = lttcomm_create_sock(sock);
 398         if (ret < 0) {
 399                 goto error;
 400         }
 401         DBG("Listening on sock %d for live", sock->fd);
 402
 403         ret = sock->ops->bind(sock);
 404         if (ret < 0) {
 405                 goto error;
 406         }
 407
 408         ret = sock->ops->listen(sock, -1);
 409         if (ret < 0) {
 410                 goto error;
 411
 412         }
 413
 414         return sock;
 415
 416 error:
 417         if (sock) {
 418                 lttcomm_destroy_sock(sock);
 419         }
 420         return NULL;
 421 }
 422
 423 /*
 424  * This thread manages the listening for new connections on the network
 425  */
 426 static
 427 void *thread_listener(void *data)
 428 {
 429         int i, ret, pollfd, err = -1;
 430         uint32_t revents, nb_fd;
 431         struct lttng_poll_event events;
 432         struct lttcomm_sock *live_control_sock;
 433
 434         DBG("[thread] Relay live listener started");
 435
 436         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_LISTENER);
 437
 438         health_code_update();
 439
 440         live_control_sock = init_socket(live_uri);
 441         if (!live_control_sock) {
 442                 goto error_sock_control;
 443         }
 444
 445         /* Pass 2 as size here for the thread quit pipe and control sockets. */
 446         ret = create_thread_poll_set(&events, 2);
 447         if (ret < 0) {
 448                 goto error_create_poll;
 449         }
 450
 451         /* Add the control socket */
 452         ret = lttng_poll_add(&events, live_control_sock->fd, LPOLLIN | LPOLLRDHUP);
 453         if (ret < 0) {
 454                 goto error_poll_add;
 455         }
 456
 457         lttng_relay_notify_ready();
 458
 459         if (testpoint(relayd_thread_live_listener)) {
 460                 goto error_testpoint;
 461         }
 462
 463         while (1) {
 464                 health_code_update();
 465
 466                 DBG("Listener accepting live viewers connections");
 467
 468 restart:
 469                 health_poll_entry();
 470                 ret = lttng_poll_wait(&events, -1);
 471                 health_poll_exit();
 472                 if (ret < 0) {
 473                         /*
 474                          * Restart interrupted system call.
 475                          */
 476                         if (errno == EINTR) {
 477                                 goto restart;
 478                         }
 479                         goto error;
 480                 }
 481                 nb_fd = ret;
 482
 483                 DBG("Relay new viewer connection received");
 484                 for (i = 0; i < nb_fd; i++) {
 485                         health_code_update();
 486
 487                         /* Fetch once the poll data */
 488                         revents = LTTNG_POLL_GETEV(&events, i);
 489                         pollfd = LTTNG_POLL_GETFD(&events, i);
 490
 491                         if (!revents) {
 492                                 /* No activity for this FD (poll implementation). */
 493                                 continue;
 494                         }
 495
 496                         /* Thread quit pipe has been closed. Killing thread. */
 497                         ret = check_thread_quit_pipe(pollfd, revents);
 498                         if (ret) {
 499                                 err = 0;
 500                                 goto exit;
 501                         }
 502
 503                         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 504                                 ERR("socket poll error");
 505                                 goto error;
 506                         } else if (revents & LPOLLIN) {
 507                                 /*
 508                                  * Get allocated in this thread, enqueued to a global queue,
 509                                  * dequeued and freed in the worker thread.
 510                                  */
 511                                 int val = 1;
 512                                 struct relay_connection *new_conn;
 513                                 struct lttcomm_sock *newsock;
 514
 515                                 new_conn = connection_create();
 516                                 if (!new_conn) {
 517                                         goto error;
 518                                 }
 519
 520                                 newsock = live_control_sock->ops->accept(live_control_sock);
 521                                 if (!newsock) {
 522                                         PERROR("accepting control sock");
 523                                         connection_free(new_conn);
 524                                         goto error;
 525                                 }
 526                                 DBG("Relay viewer connection accepted socket %d", newsock->fd);
 527
 528                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR, &val,
 529                                                 sizeof(val));
 530                                 if (ret < 0) {
 531                                         PERROR("setsockopt inet");
 532                                         lttcomm_destroy_sock(newsock);
 533                                         connection_free(new_conn);
 534                                         goto error;
 535                                 }
 536                                 new_conn->sock = newsock;
 537
 538                                 /* Enqueue request for the dispatcher thread. */
 539                                 cds_wfcq_enqueue(&viewer_conn_queue.head, &viewer_conn_queue.tail,
 540                                                  &new_conn->qnode);
 541
 542                                 /*
 543                                  * Wake the dispatch queue futex. Implicit memory barrier with
 544                                  * the exchange in cds_wfcq_enqueue.
 545                                  */
 546                                 futex_nto1_wake(&viewer_conn_queue.futex);
 547                         }
 548                 }
 549         }
 550
 551 exit:
 552 error:
 553 error_poll_add:
 554 error_testpoint:
 555         lttng_poll_clean(&events);
 556 error_create_poll:
 557         if (live_control_sock->fd >= 0) {
 558                 ret = live_control_sock->ops->close(live_control_sock);
 559                 if (ret) {
 560                         PERROR("close");
 561                 }
 562         }
 563         lttcomm_destroy_sock(live_control_sock);
 564 error_sock_control:
 565         if (err) {
 566                 health_error();
 567                 DBG("Live viewer listener thread exited with error");
 568         }
 569         health_unregister(health_relayd);
 570         DBG("Live viewer listener thread cleanup complete");
 571         if (lttng_relay_stop_threads()) {
 572                 ERR("Error stopping threads");
 573         }
 574         return NULL;
 575 }
 576
 577 /*
 578  * This thread manages the dispatching of the requests to worker threads
 579  */
 580 static
 581 void *thread_dispatcher(void *data)
 582 {
 583         int err = -1;
 584         ssize_t ret;
 585         struct cds_wfcq_node *node;
 586         struct relay_connection *conn = NULL;
 587
 588         DBG("[thread] Live viewer relay dispatcher started");
 589
 590         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 591
 592         if (testpoint(relayd_thread_live_dispatcher)) {
 593                 goto error_testpoint;
 594         }
 595
 596         health_code_update();
 597
 598         while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 599                 health_code_update();
 600
 601                 /* Atomically prepare the queue futex */
 602                 futex_nto1_prepare(&viewer_conn_queue.futex);
 603
 604                 do {
 605                         health_code_update();
 606
 607                         /* Dequeue commands */
 608                         node = cds_wfcq_dequeue_blocking(&viewer_conn_queue.head,
 609                                                          &viewer_conn_queue.tail);
 610                         if (node == NULL) {
 611                                 DBG("Woken up but nothing in the live-viewer "
 612                                                 "relay command queue");
 613                                 /* Continue thread execution */
 614                                 break;
 615                         }
 616                         conn = caa_container_of(node, struct relay_connection, qnode);
 617                         DBG("Dispatching viewer request waiting on sock %d",
 618                                         conn->sock->fd);
 619
 620                         /*
 621                          * Inform worker thread of the new request. This call is blocking
 622                          * so we can be assured that the data will be read at some point in
 623                          * time or wait to the end of the world :)
 624                          */
 625                         ret = lttng_write(live_conn_pipe[1], &conn, sizeof(conn));
 626                         if (ret < 0) {
 627                                 PERROR("write conn pipe");
 628                                 connection_destroy(conn);
 629                                 goto error;
 630                         }
 631                 } while (node != NULL);
 632
 633                 /* Futex wait on queue. Blocking call on futex() */
 634                 health_poll_entry();
 635                 futex_nto1_wait(&viewer_conn_queue.futex);
 636                 health_poll_exit();
 637         }
 638
 639         /* Normal exit, no error */
 640         err = 0;
 641
 642 error:
 643 error_testpoint:
 644         if (err) {
 645                 health_error();
 646                 ERR("Health error occurred in %s", __func__);
 647         }
 648         health_unregister(health_relayd);
 649         DBG("Live viewer dispatch thread dying");
 650         if (lttng_relay_stop_threads()) {
 651                 ERR("Error stopping threads");
 652         }
 653         return NULL;
 654 }
 655
 656 /*
 657  * Establish connection with the viewer and check the versions.
 658  *
 659  * Return 0 on success or else negative value.
 660  */
 661 static
 662 int viewer_connect(struct relay_connection *conn)
 663 {
 664         int ret;
 665         struct lttng_viewer_connect reply, msg;
 666
 667         assert(conn);
 668
 669         conn->version_check_done = 1;
 670
 671         health_code_update();
 672
 673         DBG("Viewer is establishing a connection to the relayd.");
 674
 675         ret = recv_request(conn->sock, &msg, sizeof(msg));
 676         if (ret < 0) {
 677                 goto end;
 678         }
 679
 680         health_code_update();
 681
 682         memset(&reply, 0, sizeof(reply));
 683         reply.major = RELAYD_VERSION_COMM_MAJOR;
 684         reply.minor = RELAYD_VERSION_COMM_MINOR;
 685
 686         /* Major versions must be the same */
 687         if (reply.major != be32toh(msg.major)) {
 688                 DBG("Incompatible major versions ([relayd] %u vs [client] %u)",
 689                                 reply.major, be32toh(msg.major));
 690                 ret = -1;
 691                 goto end;
 692         }
 693
 694         conn->major = reply.major;
 695         /* We adapt to the lowest compatible version */
 696         if (reply.minor <= be32toh(msg.minor)) {
 697                 conn->minor = reply.minor;
 698         } else {
 699                 conn->minor = be32toh(msg.minor);
 700         }
 701
 702         if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_COMMAND) {
 703                 conn->type = RELAY_VIEWER_COMMAND;
 704         } else if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_NOTIFICATION) {
 705                 conn->type = RELAY_VIEWER_NOTIFICATION;
 706         } else {
 707                 ERR("Unknown connection type : %u", be32toh(msg.type));
 708                 ret = -1;
 709                 goto end;
 710         }
 711
 712         reply.major = htobe32(reply.major);
 713         reply.minor = htobe32(reply.minor);
 714         if (conn->type == RELAY_VIEWER_COMMAND) {
 715                 /*
 716                  * Increment outside of htobe64 macro, because can be used more than once
 717                  * within the macro, and thus the operation may be undefined.
 718                  */
 719                 last_relay_viewer_session_id++;
 720                 reply.viewer_session_id = htobe64(last_relay_viewer_session_id);
 721         }
 722
 723         health_code_update();
 724
 725         ret = send_response(conn->sock, &reply, sizeof(reply));
 726         if (ret < 0) {
 727                 goto end;
 728         }
 729
 730         health_code_update();
 731
 732         DBG("Version check done using protocol %u.%u", conn->major, conn->minor);
 733         ret = 0;
 734
 735 end:
 736         return ret;
 737 }
 738
 739 /*
 740  * Send the viewer the list of current sessions.
 741  *
 742  * Return 0 on success or else a negative value.
 743  */
 744 static
 745 int viewer_list_sessions(struct relay_connection *conn)
 746 {
 747         int ret;
 748         struct lttng_viewer_list_sessions session_list;
 749         unsigned long count;
 750         long approx_before, approx_after;
 751         struct lttng_ht_iter iter;
 752         struct lttng_viewer_session send_session;
 753         struct relay_session *session;
 754
 755         DBG("List sessions received");
 756
 757         rcu_read_lock();
 758         cds_lfht_count_nodes(conn->sessions_ht->ht, &approx_before, &count,
 759                         &approx_after);
 760         session_list.sessions_count = htobe32(count);
 761
 762         health_code_update();
 763
 764         ret = send_response(conn->sock, &session_list, sizeof(session_list));
 765         if (ret < 0) {
 766                 goto end_unlock;
 767         }
 768
 769         health_code_update();
 770
 771         cds_lfht_for_each_entry(conn->sessions_ht->ht, &iter.iter, session,
 772                         session_n.node) {
 773                 health_code_update();
 774
 775                 strncpy(send_session.session_name, session->session_name,
 776                                 sizeof(send_session.session_name));
 777                 strncpy(send_session.hostname, session->hostname,
 778                                 sizeof(send_session.hostname));
 779                 send_session.id = htobe64(session->id);
 780                 send_session.live_timer = htobe32(session->live_timer);
 781                 send_session.clients = htobe32(session->viewer_refcount);
 782                 send_session.streams = htobe32(session->stream_count);
 783
 784                 health_code_update();
 785
 786                 ret = send_response(conn->sock, &send_session, sizeof(send_session));
 787                 if (ret < 0) {
 788                         goto end_unlock;
 789                 }
 790         }
 791         health_code_update();
 792
 793         ret = 0;
 794 end_unlock:
 795         rcu_read_unlock();
 796         return ret;
 797 }
 798
 799 /*
 800  * Check if a connection is attached to a session.
 801  * Return 1 if attached, 0 if not attached, a negative value on error.
 802  */
 803 static
 804 int session_attached(struct relay_connection *conn, uint64_t session_id)
 805 {
 806         struct relay_session *session;
 807         int found = 0;
 808
 809         if (!conn->viewer_session) {
 810                 goto end;
 811         }
 812         cds_list_for_each_entry(session,
 813                         &conn->viewer_session->sessions_head,
 814                         viewer_session_list) {
 815                 if (session->id == session_id) {
 816                         found = 1;
 817                         goto end;
 818                 }
 819         }
 820
 821 end:
 822         return found;
 823 }
 824
 825 /*
 826  * Delete all streams for a specific session ID.
 827  */
 828 static void destroy_viewer_streams_by_session(struct relay_session *session)
 829 {
 830         struct relay_viewer_stream *stream;
 831         struct lttng_ht_iter iter;
 832
 833         assert(session);
 834
 835         rcu_read_lock();
 836         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, stream,
 837                         stream_n.node) {
 838                 struct ctf_trace *ctf_trace;
 839
 840                 health_code_update();
 841                 if (stream->session_id != session->id) {
 842                         continue;
 843                 }
 844
 845                 ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
 846                                 stream->path_name);
 847                 assert(ctf_trace);
 848
 849                 viewer_stream_delete(stream);
 850
 851                 if (stream->metadata_flag) {
 852                         ctf_trace->metadata_sent = 0;
 853                         ctf_trace->viewer_metadata_stream = NULL;
 854                 }
 855
 856                 viewer_stream_destroy(ctf_trace, stream);
 857         }
 858         rcu_read_unlock();
 859 }
 860
 861 static void try_destroy_streams(struct relay_session *session)
 862 {
 863         struct ctf_trace *ctf_trace;
 864         struct lttng_ht_iter iter;
 865
 866         assert(session);
 867
 868         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 869                         node.node) {
 870                 /* Attempt to destroy the ctf trace of that session. */
 871                 ctf_trace_try_destroy(session, ctf_trace);
 872         }
 873 }
 874
 875 /*
 876  * Cleanup a session.
 877  */
 878 static void cleanup_session(struct relay_connection *conn,
 879                 struct relay_session *session)
 880 {
 881         /*
 882          * Very important that this is done before destroying the session so we
 883          * can put back every viewer stream reference from the ctf_trace.
 884          */
 885         destroy_viewer_streams_by_session(session);
 886         try_destroy_streams(session);
 887         cds_list_del(&session->viewer_session_list);
 888         session_viewer_try_destroy(conn->sessions_ht, session);
 889 }
 890
 891 /*
 892  * Send the viewer the list of current sessions.
 893  */
 894 static
 895 int viewer_get_new_streams(struct relay_connection *conn)
 896 {
 897         int ret, send_streams = 0;
 898         uint32_t nb_created = 0, nb_unsent = 0, nb_streams = 0;
 899         struct lttng_viewer_new_streams_request request;
 900         struct lttng_viewer_new_streams_response response;
 901         struct relay_session *session;
 902         uint64_t session_id;
 903
 904         assert(conn);
 905
 906         DBG("Get new streams received");
 907
 908         health_code_update();
 909
 910         /* Receive the request from the connected client. */
 911         ret = recv_request(conn->sock, &request, sizeof(request));
 912         if (ret < 0) {
 913                 goto error;
 914         }
 915         session_id = be64toh(request.session_id);
 916
 917         health_code_update();
 918
 919         memset(&response, 0, sizeof(response));
 920
 921         rcu_read_lock();
 922         session = session_find_by_id(conn->sessions_ht, session_id);
 923         if (!session) {
 924                 DBG("Relay session %" PRIu64 " not found", session_id);
 925                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 926                 goto send_reply;
 927         }
 928
 929         if (!session_attached(conn, session_id)) {
 930                 send_streams = 0;
 931                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 932                 goto send_reply;
 933         }
 934
 935         send_streams = 1;
 936         response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 937
 938         ret = make_viewer_streams(session, LTTNG_VIEWER_SEEK_LAST, NULL, &nb_unsent,
 939                         &nb_created);
 940         if (ret < 0) {
 941                 goto end_unlock;
 942         }
 943         /* Only send back the newly created streams with the unsent ones. */
 944         nb_streams = nb_created + nb_unsent;
 945         response.streams_count = htobe32(nb_streams);
 946
 947         /*
 948          * If the session is closed and we have no new streams to send,
 949          * it means that the viewer has already received the whole trace
 950          * for this session and should now close it.
 951          */
 952         if (nb_streams == 0 && session->close_flag) {
 953                 send_streams = 0;
 954                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
 955                 /*
 956                  * Remove the session from the attached list of the connection
 957                  * and try to destroy it.
 958                  */
 959                 cds_list_del(&session->viewer_session_list);
 960                 cleanup_session(conn, session);
 961                 goto send_reply;
 962         }
 963
 964 send_reply:
 965         health_code_update();
 966         ret = send_response(conn->sock, &response, sizeof(response));
 967         if (ret < 0) {
 968                 goto end_unlock;
 969         }
 970         health_code_update();
 971
 972         /*
 973          * Unknown or empty session, just return gracefully, the viewer knows what
 974          * is happening.
 975          */
 976         if (!send_streams || !nb_streams) {
 977                 ret = 0;
 978                 goto end_unlock;
 979         }
 980
 981         /*
 982          * Send stream and *DON'T* ignore the sent flag so every viewer streams
 983          * that were not sent from that point will be sent to the viewer.
 984          */
 985         ret = send_viewer_streams(conn->sock, session, 0);
 986         if (ret < 0) {
 987                 goto end_unlock;
 988         }
 989
 990 end_unlock:
 991         rcu_read_unlock();
 992 error:
 993         return ret;
 994 }
 995
 996 /*
 997  * Send the viewer the list of current sessions.
 998  */
 999 static
1000 int viewer_attach_session(struct relay_connection *conn)
1001 {
1002         int send_streams = 0;
1003         ssize_t ret;
1004         uint32_t nb_streams = 0;
1005         enum lttng_viewer_seek seek_type;
1006         struct lttng_viewer_attach_session_request request;
1007         struct lttng_viewer_attach_session_response response;
1008         struct relay_session *session;
1009
1010         assert(conn);
1011
1012         health_code_update();
1013
1014         /* Receive the request from the connected client. */
1015         ret = recv_request(conn->sock, &request, sizeof(request));
1016         if (ret < 0) {
1017                 goto error;
1018         }
1019
1020         health_code_update();
1021
1022         memset(&response, 0, sizeof(response));
1023
1024         if (!conn->viewer_session) {
1025                 DBG("Client trying to attach before creating a live viewer session");
1026                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NO_SESSION);
1027                 goto send_reply;
1028         }
1029
1030         rcu_read_lock();
1031         session = session_find_by_id(conn->sessions_ht,
1032                         be64toh(request.session_id));
1033         if (!session) {
1034                 DBG("Relay session %" PRIu64 " not found",
1035                                 be64toh(request.session_id));
1036                 response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
1037                 goto send_reply;
1038         }
1039         session_viewer_attach(session);
1040         DBG("Attach session ID %" PRIu64 " received", be64toh(request.session_id));
1041
1042         if (uatomic_read(&session->viewer_refcount) > 1) {
1043                 DBG("Already a viewer attached");
1044                 response.status = htobe32(LTTNG_VIEWER_ATTACH_ALREADY);
1045                 session_viewer_detach(session);
1046                 goto send_reply;
1047         } else if (session->live_timer == 0) {
1048                 DBG("Not live session");
1049                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NOT_LIVE);
1050                 goto send_reply;
1051         } else {
1052                 send_streams = 1;
1053                 response.status = htobe32(LTTNG_VIEWER_ATTACH_OK);
1054                 cds_list_add(&session->viewer_session_list,
1055                                 &conn->viewer_session->sessions_head);
1056         }
1057
1058         switch (be32toh(request.seek)) {
1059         case LTTNG_VIEWER_SEEK_BEGINNING:
1060         case LTTNG_VIEWER_SEEK_LAST:
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, NULL);
1071         if (ret < 0) {
1072                 goto end_unlock;
1073         }
1074         response.streams_count = htobe32(nb_streams);
1075
1076 send_reply:
1077         health_code_update();
1078         ret = send_response(conn->sock, &response, sizeof(response));
1079         if (ret < 0) {
1080                 goto end_unlock;
1081         }
1082         health_code_update();
1083
1084         /*
1085          * Unknown or empty session, just return gracefully, the viewer knows what
1086          * is happening.
1087          */
1088         if (!send_streams || !nb_streams) {
1089                 ret = 0;
1090                 goto end_unlock;
1091         }
1092
1093         /* Send stream and ignore the sent flag. */
1094         ret = send_viewer_streams(conn->sock, session, 1);
1095         if (ret < 0) {
1096                 goto end_unlock;
1097         }
1098
1099 end_unlock:
1100         rcu_read_unlock();
1101 error:
1102         return ret;
1103 }
1104
1105 /*
1106  * Open the index file if needed for the given vstream.
1107  *
1108  * If an index file is successfully opened, the index_read_fd of the stream is
1109  * set with it.
1110  *
1111  * Return 0 on success, a negative value on error (-ENOENT if not ready yet).
1112  */
1113 static int try_open_index(struct relay_viewer_stream *vstream,
1114                 struct relay_stream *rstream)
1115 {
1116         int ret = 0;
1117
1118         assert(vstream);
1119         assert(rstream);
1120
1121         if (vstream->index_read_fd >= 0) {
1122                 goto end;
1123         }
1124
1125         /*
1126          * First time, we open the index file and at least one index is ready.  The
1127          * race between the read and write of the total_index_received is
1128          * acceptable here since the client will be notified to simply come back
1129          * and get the next index.
1130          */
1131         if (rstream->total_index_received <= 0) {
1132                 ret = -ENOENT;
1133                 goto end;
1134         }
1135         ret = index_open(vstream->path_name, vstream->channel_name,
1136                         vstream->tracefile_count, vstream->tracefile_count_current);
1137         if (ret >= 0) {
1138                 vstream->index_read_fd = ret;
1139                 ret = 0;
1140                 goto end;
1141         }
1142
1143 end:
1144         return ret;
1145 }
1146
1147 /*
1148  * Check the status of the index for the given stream. This function updates
1149  * the index structure if needed and can destroy the vstream also for the HUP
1150  * situation.
1151  *
1152  * Return 0 means that we can proceed with the index. A value of 1 means that
1153  * the index has been updated and is ready to be send to the client. A negative
1154  * value indicates an error that can't be handled.
1155  */
1156 static int check_index_status(struct relay_viewer_stream *vstream,
1157                 struct relay_stream *rstream, struct ctf_trace *trace,
1158                 struct lttng_viewer_index *index)
1159 {
1160         int ret;
1161
1162         assert(vstream);
1163         assert(rstream);
1164         assert(index);
1165         assert(trace);
1166
1167         if (!rstream->close_flag) {
1168                 /* Rotate on abort (overwrite). */
1169                 if (vstream->abort_flag) {
1170                         DBG("Viewer stream %" PRIu64 " rotate because of overwrite",
1171                                         vstream->stream_handle);
1172                         ret = viewer_stream_rotate(vstream, rstream);
1173                         if (ret < 0) {
1174                                 goto error;
1175                         } else if (ret == 1) {
1176                                 /* EOF */
1177                                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1178                                 goto hup;
1179                         }
1180                         /* ret == 0 means successful so we continue. */
1181                 }
1182
1183                 /* Check if we are in the same trace file at this point. */
1184                 if (rstream->tracefile_count_current == vstream->tracefile_count_current) {
1185                         if (rstream->beacon_ts_end != -1ULL &&
1186                                         vstream->last_sent_index == rstream->total_index_received) {
1187                                 /*
1188                                  * We've received a synchronization beacon and the last index
1189                                  * available has been sent, the index for now is inactive.
1190                                  */
1191                                 index->status = htobe32(LTTNG_VIEWER_INDEX_INACTIVE);
1192                                 index->timestamp_end = htobe64(rstream->beacon_ts_end);
1193                                 index->stream_id = htobe64(rstream->ctf_stream_id);
1194                                 goto index_ready;
1195                         } else if (rstream->total_index_received <= vstream->last_sent_index
1196                                         && !vstream->close_write_flag) {
1197                                 /*
1198                                  * Reader and writer are working in the same tracefile, so we care
1199                                  * about the number of index received and sent. Otherwise, we read
1200                                  * up to EOF.
1201                                  */
1202                                 index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1203                                 goto index_ready;
1204                         }
1205                 }
1206                 /* Nothing to do with the index, continue with it. */
1207                 ret = 0;
1208         } else if (rstream->close_flag && vstream->close_write_flag &&
1209                         vstream->total_index_received == vstream->last_sent_index) {
1210                 /* Last index sent and current tracefile closed in write */
1211                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1212                 goto hup;
1213         } else {
1214                 vstream->close_write_flag = 1;
1215                 ret = 0;
1216         }
1217
1218 error:
1219         return ret;
1220
1221 hup:
1222         viewer_stream_delete(vstream);
1223         viewer_stream_destroy(trace, vstream);
1224 index_ready:
1225         return 1;
1226 }
1227
1228 /*
1229  * Send the next index for a stream.
1230  *
1231  * Return 0 on success or else a negative value.
1232  */
1233 static
1234 int viewer_get_next_index(struct relay_connection *conn)
1235 {
1236         int ret;
1237         ssize_t read_ret;
1238         struct lttng_viewer_get_next_index request_index;
1239         struct lttng_viewer_index viewer_index;
1240         struct ctf_packet_index packet_index;
1241         struct relay_viewer_stream *vstream;
1242         struct relay_stream *rstream;
1243         struct ctf_trace *ctf_trace;
1244         struct relay_session *session;
1245
1246         assert(conn);
1247
1248         DBG("Viewer get next index");
1249
1250         health_code_update();
1251
1252         ret = recv_request(conn->sock, &request_index, sizeof(request_index));
1253         if (ret < 0) {
1254                 goto end;
1255         }
1256         health_code_update();
1257
1258         rcu_read_lock();
1259         vstream = viewer_stream_find_by_id(be64toh(request_index.stream_id));
1260         if (!vstream) {
1261                 ret = -1;
1262                 goto end_unlock;
1263         }
1264
1265         session = session_find_by_id(conn->sessions_ht, vstream->session_id);
1266         if (!session) {
1267                 ret = -1;
1268                 goto end_unlock;
1269         }
1270
1271         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht, vstream->path_name);
1272         assert(ctf_trace);
1273
1274         memset(&viewer_index, 0, sizeof(viewer_index));
1275
1276         /*
1277          * The viewer should not ask for index on metadata stream.
1278          */
1279         if (vstream->metadata_flag) {
1280                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1281                 goto send_reply;
1282         }
1283
1284         rstream = stream_find_by_id(relay_streams_ht, vstream->stream_handle);
1285         assert(rstream);
1286
1287         /* Try to open an index if one is needed for that stream. */
1288         ret = try_open_index(vstream, rstream);
1289         if (ret < 0) {
1290                 if (ret == -ENOENT) {
1291                         /*
1292                          * The index is created only when the first data packet arrives, it
1293                          * might not be ready at the beginning of the session
1294                          */
1295                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1296                 } else {
1297                         /* Unhandled error. */
1298                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1299                 }
1300                 goto send_reply;
1301         }
1302
1303         pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1304         ret = check_index_status(vstream, rstream, ctf_trace, &viewer_index);
1305         pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1306         if (ret < 0) {
1307                 goto end_unlock;
1308         } else if (ret == 1) {
1309                 /*
1310                  * This means the viewer index data structure has been populated by the
1311                  * check call thus we now send back the reply to the client.
1312                  */
1313                 goto send_reply;
1314         }
1315         /* At this point, ret MUST be 0 thus we continue with the get. */
1316         assert(!ret);
1317
1318         if (!ctf_trace->metadata_received ||
1319                         ctf_trace->metadata_received > ctf_trace->metadata_sent) {
1320                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1321         }
1322
1323         ret = check_new_streams(conn);
1324         if (ret < 0) {
1325                 goto end_unlock;
1326         } else if (ret == 1) {
1327                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1328         }
1329
1330         pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1331         pthread_mutex_lock(&vstream->overwrite_lock);
1332         if (vstream->abort_flag) {
1333                 /* The file is being overwritten by the writer, we cannot use it. */
1334                 pthread_mutex_unlock(&vstream->overwrite_lock);
1335                 ret = viewer_stream_rotate(vstream, rstream);
1336                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1337                 if (ret < 0) {
1338                         goto end_unlock;
1339                 } else if (ret == 1) {
1340                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1341                         viewer_stream_delete(vstream);
1342                         viewer_stream_destroy(ctf_trace, vstream);
1343                 } else {
1344                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1345                 }
1346                 goto send_reply;
1347         }
1348
1349         read_ret = lttng_read(vstream->index_read_fd, &packet_index,
1350                         sizeof(packet_index));
1351         pthread_mutex_unlock(&vstream->overwrite_lock);
1352         pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1353         if (read_ret < 0) {
1354                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1355                 viewer_stream_delete(vstream);
1356                 viewer_stream_destroy(ctf_trace, vstream);
1357                 goto send_reply;
1358         } else if (read_ret < sizeof(packet_index)) {
1359                 pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1360                 if (vstream->close_write_flag) {
1361                         ret = viewer_stream_rotate(vstream, rstream);
1362                         if (ret < 0) {
1363                                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1364                                 goto end_unlock;
1365                         } else if (ret == 1) {
1366                                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1367                                 viewer_stream_delete(vstream);
1368                                 viewer_stream_destroy(ctf_trace, vstream);
1369                         } else {
1370                                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1371                         }
1372                 } else {
1373                         ERR("Relay reading index file %d", vstream->index_read_fd);
1374                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1375                 }
1376                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1377                 goto send_reply;
1378         } else {
1379                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_OK);
1380                 vstream->last_sent_index++;
1381         }
1382
1383         /*
1384          * Indexes are stored in big endian, no need to switch before sending.
1385          */
1386         viewer_index.offset = packet_index.offset;
1387         viewer_index.packet_size = packet_index.packet_size;
1388         viewer_index.content_size = packet_index.content_size;
1389         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1390         viewer_index.timestamp_end = packet_index.timestamp_end;
1391         viewer_index.events_discarded = packet_index.events_discarded;
1392         viewer_index.stream_id = packet_index.stream_id;
1393
1394 send_reply:
1395         viewer_index.flags = htobe32(viewer_index.flags);
1396         health_code_update();
1397
1398         ret = send_response(conn->sock, &viewer_index, sizeof(viewer_index));
1399         if (ret < 0) {
1400                 goto end_unlock;
1401         }
1402         health_code_update();
1403
1404         DBG("Index %" PRIu64 " for stream %" PRIu64 " sent",
1405                         vstream->last_sent_index, vstream->stream_handle);
1406
1407 end_unlock:
1408         rcu_read_unlock();
1409
1410 end:
1411         return ret;
1412 }
1413
1414 /*
1415  * Send the next index for a stream
1416  *
1417  * Return 0 on success or else a negative value.
1418  */
1419 static
1420 int viewer_get_packet(struct relay_connection *conn)
1421 {
1422         int ret, send_data = 0;
1423         char *data = NULL;
1424         uint32_t len = 0;
1425         ssize_t read_len;
1426         struct lttng_viewer_get_packet get_packet_info;
1427         struct lttng_viewer_trace_packet reply;
1428         struct relay_viewer_stream *stream;
1429         struct relay_session *session;
1430         struct ctf_trace *ctf_trace;
1431
1432         assert(conn);
1433
1434         DBG2("Relay get data packet");
1435
1436         health_code_update();
1437
1438         ret = recv_request(conn->sock, &get_packet_info, sizeof(get_packet_info));
1439         if (ret < 0) {
1440                 goto end;
1441         }
1442         health_code_update();
1443
1444         /* From this point on, the error label can be reached. */
1445         memset(&reply, 0, sizeof(reply));
1446
1447         rcu_read_lock();
1448         stream = viewer_stream_find_by_id(be64toh(get_packet_info.stream_id));
1449         if (!stream) {
1450                 goto error;
1451         }
1452
1453         session = session_find_by_id(conn->sessions_ht, stream->session_id);
1454         if (!session) {
1455                 ret = -1;
1456                 goto error;
1457         }
1458
1459         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
1460                         stream->path_name);
1461         assert(ctf_trace);
1462
1463         /*
1464          * First time we read this stream, we need open the tracefile, we should
1465          * only arrive here if an index has already been sent to the viewer, so the
1466          * tracefile must exist, if it does not it is a fatal error.
1467          */
1468         if (stream->read_fd < 0) {
1469                 char fullpath[PATH_MAX];
1470
1471                 if (stream->tracefile_count > 0) {
1472                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64, stream->path_name,
1473                                         stream->channel_name,
1474                                         stream->tracefile_count_current);
1475                 } else {
1476                         ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1477                                         stream->channel_name);
1478                 }
1479                 if (ret < 0) {
1480                         goto error;
1481                 }
1482                 ret = open(fullpath, O_RDONLY);
1483                 if (ret < 0) {
1484                         PERROR("Relay opening trace file");
1485                         goto error;
1486                 }
1487                 stream->read_fd = ret;
1488         }
1489
1490         if (!ctf_trace->metadata_received ||
1491                         ctf_trace->metadata_received > ctf_trace->metadata_sent) {
1492                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1493                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1494                 goto send_reply;
1495         }
1496
1497         ret = check_new_streams(conn);
1498         if (ret < 0) {
1499                 goto end_unlock;
1500         } else if (ret == 1) {
1501                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1502                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1503                 goto send_reply;
1504         }
1505
1506         len = be32toh(get_packet_info.len);
1507         data = zmalloc(len);
1508         if (!data) {
1509                 PERROR("relay data zmalloc");
1510                 goto error;
1511         }
1512
1513         ret = lseek(stream->read_fd, be64toh(get_packet_info.offset), SEEK_SET);
1514         if (ret < 0) {
1515                 /*
1516                  * If the read fd was closed by the streaming side, the
1517                  * abort_flag will be set to 1, otherwise it is an error.
1518                  */
1519                 if (stream->abort_flag == 0) {
1520                         PERROR("lseek");
1521                         goto error;
1522                 }
1523                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_EOF);
1524                 goto send_reply;
1525         }
1526         read_len = lttng_read(stream->read_fd, data, len);
1527         if (read_len < len) {
1528                 /*
1529                  * If the read fd was closed by the streaming side, the
1530                  * abort_flag will be set to 1, otherwise it is an error.
1531                  */
1532                 if (stream->abort_flag == 0) {
1533                         PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1534                                         stream->read_fd,
1535                                         be64toh(get_packet_info.offset));
1536                         goto error;
1537                 } else {
1538                         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_EOF);
1539                         goto send_reply;
1540                 }
1541         }
1542         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_OK);
1543         reply.len = htobe32(len);
1544         send_data = 1;
1545         goto send_reply;
1546
1547 error:
1548         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1549
1550 send_reply:
1551         reply.flags = htobe32(reply.flags);
1552
1553         health_code_update();
1554
1555         ret = send_response(conn->sock, &reply, sizeof(reply));
1556         if (ret < 0) {
1557                 goto end_unlock;
1558         }
1559         health_code_update();
1560
1561         if (send_data) {
1562                 health_code_update();
1563                 ret = send_response(conn->sock, data, len);
1564                 if (ret < 0) {
1565                         goto end_unlock;
1566                 }
1567                 health_code_update();
1568         }
1569
1570         DBG("Sent %u bytes for stream %" PRIu64, len,
1571                         be64toh(get_packet_info.stream_id));
1572
1573 end_unlock:
1574         free(data);
1575         rcu_read_unlock();
1576
1577 end:
1578         return ret;
1579 }
1580
1581 /*
1582  * Send the session's metadata
1583  *
1584  * Return 0 on success else a negative value.
1585  */
1586 static
1587 int viewer_get_metadata(struct relay_connection *conn)
1588 {
1589         int ret = 0;
1590         ssize_t read_len;
1591         uint64_t len = 0;
1592         char *data = NULL;
1593         struct lttng_viewer_get_metadata request;
1594         struct lttng_viewer_metadata_packet reply;
1595         struct relay_viewer_stream *stream;
1596         struct ctf_trace *ctf_trace;
1597         struct relay_session *session;
1598
1599         assert(conn);
1600
1601         DBG("Relay get metadata");
1602
1603         health_code_update();
1604
1605         ret = recv_request(conn->sock, &request, sizeof(request));
1606         if (ret < 0) {
1607                 goto end;
1608         }
1609         health_code_update();
1610
1611         memset(&reply, 0, sizeof(reply));
1612
1613         rcu_read_lock();
1614         stream = viewer_stream_find_by_id(be64toh(request.stream_id));
1615         if (!stream || !stream->metadata_flag) {
1616                 ERR("Invalid metadata stream");
1617                 goto error;
1618         }
1619
1620         session = session_find_by_id(conn->sessions_ht, stream->session_id);
1621         if (!session) {
1622                 ret = -1;
1623                 goto error;
1624         }
1625
1626         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
1627                         stream->path_name);
1628         assert(ctf_trace);
1629         assert(ctf_trace->metadata_sent <= ctf_trace->metadata_received);
1630
1631         len = ctf_trace->metadata_received - ctf_trace->metadata_sent;
1632         if (len == 0) {
1633                 reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
1634                 goto send_reply;
1635         }
1636
1637         /* first time, we open the metadata file */
1638         if (stream->read_fd < 0) {
1639                 char fullpath[PATH_MAX];
1640
1641                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1642                                 stream->channel_name);
1643                 if (ret < 0) {
1644                         goto error;
1645                 }
1646                 ret = open(fullpath, O_RDONLY);
1647                 if (ret < 0) {
1648                         PERROR("Relay opening metadata file");
1649                         goto error;
1650                 }
1651                 stream->read_fd = ret;
1652         }
1653
1654         reply.len = htobe64(len);
1655         data = zmalloc(len);
1656         if (!data) {
1657                 PERROR("viewer metadata zmalloc");
1658                 goto error;
1659         }
1660
1661         read_len = lttng_read(stream->read_fd, data, len);
1662         if (read_len < len) {
1663                 PERROR("Relay reading metadata file");
1664                 goto error;
1665         }
1666         ctf_trace->metadata_sent += read_len;
1667         reply.status = htobe32(LTTNG_VIEWER_METADATA_OK);
1668         goto send_reply;
1669
1670 error:
1671         reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1672
1673 send_reply:
1674         health_code_update();
1675         ret = send_response(conn->sock, &reply, sizeof(reply));
1676         if (ret < 0) {
1677                 goto end_unlock;
1678         }
1679         health_code_update();
1680
1681         if (len > 0) {
1682                 ret = send_response(conn->sock, data, len);
1683                 if (ret < 0) {
1684                         goto end_unlock;
1685                 }
1686         }
1687
1688         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1689                         be64toh(request.stream_id));
1690
1691         DBG("Metadata sent");
1692
1693 end_unlock:
1694         free(data);
1695         rcu_read_unlock();
1696 end:
1697         return ret;
1698 }
1699
1700 /*
1701  * Create a viewer session.
1702  *
1703  * Return 0 on success or else a negative value.
1704  */
1705 static
1706 int viewer_create_session(struct relay_connection *conn)
1707 {
1708         int ret;
1709         struct lttng_viewer_create_session_response resp;
1710
1711         DBG("Viewer create session received");
1712
1713         memset(&resp, 0, sizeof(resp));
1714         resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_OK);
1715         conn->viewer_session = zmalloc(sizeof(*conn->viewer_session));
1716         if (!conn->viewer_session) {
1717                 ERR("Allocation viewer session");
1718                 resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_ERR);
1719                 goto send_reply;
1720         }
1721         CDS_INIT_LIST_HEAD(&conn->viewer_session->sessions_head);
1722
1723 send_reply:
1724         health_code_update();
1725         ret = send_response(conn->sock, &resp, sizeof(resp));
1726         if (ret < 0) {
1727                 goto end;
1728         }
1729         health_code_update();
1730         ret = 0;
1731
1732 end:
1733         return ret;
1734 }
1735
1736
1737 /*
1738  * live_relay_unknown_command: send -1 if received unknown command
1739  */
1740 static
1741 void live_relay_unknown_command(struct relay_connection *conn)
1742 {
1743         struct lttcomm_relayd_generic_reply reply;
1744
1745         memset(&reply, 0, sizeof(reply));
1746         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1747         (void) send_response(conn->sock, &reply, sizeof(reply));
1748 }
1749
1750 /*
1751  * Process the commands received on the control socket
1752  */
1753 static
1754 int process_control(struct lttng_viewer_cmd *recv_hdr,
1755                 struct relay_connection *conn)
1756 {
1757         int ret = 0;
1758         uint32_t msg_value;
1759
1760         assert(recv_hdr);
1761         assert(conn);
1762
1763         msg_value = be32toh(recv_hdr->cmd);
1764
1765         /*
1766          * Make sure we've done the version check before any command other then a
1767          * new client connection.
1768          */
1769         if (msg_value != LTTNG_VIEWER_CONNECT && !conn->version_check_done) {
1770                 ERR("Viewer conn value %" PRIu32 " before version check", msg_value);
1771                 ret = -1;
1772                 goto end;
1773         }
1774
1775         switch (msg_value) {
1776         case LTTNG_VIEWER_CONNECT:
1777                 ret = viewer_connect(conn);
1778                 break;
1779         case LTTNG_VIEWER_LIST_SESSIONS:
1780                 ret = viewer_list_sessions(conn);
1781                 break;
1782         case LTTNG_VIEWER_ATTACH_SESSION:
1783                 ret = viewer_attach_session(conn);
1784                 break;
1785         case LTTNG_VIEWER_GET_NEXT_INDEX:
1786                 ret = viewer_get_next_index(conn);
1787                 break;
1788         case LTTNG_VIEWER_GET_PACKET:
1789                 ret = viewer_get_packet(conn);
1790                 break;
1791         case LTTNG_VIEWER_GET_METADATA:
1792                 ret = viewer_get_metadata(conn);
1793                 break;
1794         case LTTNG_VIEWER_GET_NEW_STREAMS:
1795                 ret = viewer_get_new_streams(conn);
1796                 break;
1797         case LTTNG_VIEWER_CREATE_SESSION:
1798                 ret = viewer_create_session(conn);
1799                 break;
1800         default:
1801                 ERR("Received unknown viewer command (%u)", be32toh(recv_hdr->cmd));
1802                 live_relay_unknown_command(conn);
1803                 ret = -1;
1804                 goto end;
1805         }
1806
1807 end:
1808         return ret;
1809 }
1810
1811 static
1812 void cleanup_connection_pollfd(struct lttng_poll_event *events, int pollfd)
1813 {
1814         int ret;
1815
1816         assert(events);
1817
1818         (void) lttng_poll_del(events, pollfd);
1819
1820         ret = close(pollfd);
1821         if (ret < 0) {
1822                 ERR("Closing pollfd %d", pollfd);
1823         }
1824 }
1825
1826 /*
1827  * Delete and destroy a connection.
1828  *
1829  * RCU read side lock MUST be acquired.
1830  */
1831 static void destroy_connection(struct lttng_ht *relay_connections_ht,
1832                 struct relay_connection *conn)
1833 {
1834         struct relay_session *session, *tmp_session;
1835
1836         assert(relay_connections_ht);
1837         assert(conn);
1838
1839         connection_delete(relay_connections_ht, conn);
1840
1841         if (!conn->viewer_session) {
1842                 goto end;
1843         }
1844
1845         rcu_read_lock();
1846         cds_list_for_each_entry_safe(session, tmp_session,
1847                         &conn->viewer_session->sessions_head,
1848                         viewer_session_list) {
1849                 DBG("Cleaning connection of session ID %" PRIu64, session->id);
1850                 cleanup_session(conn, session);
1851         }
1852         rcu_read_unlock();
1853
1854 end:
1855         connection_destroy(conn);
1856 }
1857
1858 /*
1859  * This thread does the actual work
1860  */
1861 static
1862 void *thread_worker(void *data)
1863 {
1864         int ret, err = -1;
1865         uint32_t nb_fd;
1866         struct relay_connection *conn;
1867         struct lttng_poll_event events;
1868         struct lttng_ht *relay_connections_ht;
1869         struct lttng_ht_iter iter;
1870         struct lttng_viewer_cmd recv_hdr;
1871         struct relay_local_data *relay_ctx = (struct relay_local_data *) data;
1872         struct lttng_ht *sessions_ht = relay_ctx->sessions_ht;
1873
1874         DBG("[thread] Live viewer relay worker started");
1875
1876         rcu_register_thread();
1877
1878         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1879
1880         if (testpoint(relayd_thread_live_worker)) {
1881                 goto error_testpoint;
1882         }
1883
1884         /* table of connections indexed on socket */
1885         relay_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1886         if (!relay_connections_ht) {
1887                 goto relay_connections_ht_error;
1888         }
1889
1890         ret = create_thread_poll_set(&events, 2);
1891         if (ret < 0) {
1892                 goto error_poll_create;
1893         }
1894
1895         ret = lttng_poll_add(&events, live_conn_pipe[0], LPOLLIN | LPOLLRDHUP);
1896         if (ret < 0) {
1897                 goto error;
1898         }
1899
1900 restart:
1901         while (1) {
1902                 int i;
1903
1904                 health_code_update();
1905
1906                 /* Infinite blocking call, waiting for transmission */
1907                 DBG3("Relayd live viewer worker thread polling...");
1908                 health_poll_entry();
1909                 ret = lttng_poll_wait(&events, -1);
1910                 health_poll_exit();
1911                 if (ret < 0) {
1912                         /*
1913                          * Restart interrupted system call.
1914                          */
1915                         if (errno == EINTR) {
1916                                 goto restart;
1917                         }
1918                         goto error;
1919                 }
1920
1921                 nb_fd = ret;
1922
1923                 /*
1924                  * Process control. The control connection is prioritised so we don't
1925                  * starve it with high throughput tracing data on the data
1926                  * connection.
1927                  */
1928                 for (i = 0; i < nb_fd; i++) {
1929                         /* Fetch once the poll data */
1930                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1931                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1932
1933                         health_code_update();
1934
1935                         if (!revents) {
1936                                 /* No activity for this FD (poll implementation). */
1937                                 continue;
1938                         }
1939
1940                         /* Thread quit pipe has been closed. Killing thread. */
1941                         ret = check_thread_quit_pipe(pollfd, revents);
1942                         if (ret) {
1943                                 err = 0;
1944                                 goto exit;
1945                         }
1946
1947                         /* Inspect the relay conn pipe for new connection */
1948                         if (pollfd == live_conn_pipe[0]) {
1949                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1950                                         ERR("Relay live pipe error");
1951                                         goto error;
1952                                 } else if (revents & LPOLLIN) {
1953                                         ret = lttng_read(live_conn_pipe[0], &conn, sizeof(conn));
1954                                         if (ret < 0) {
1955                                                 goto error;
1956                                         }
1957                                         conn->sessions_ht = sessions_ht;
1958                                         connection_init(conn);
1959                                         lttng_poll_add(&events, conn->sock->fd,
1960                                                         LPOLLIN | LPOLLRDHUP);
1961                                         rcu_read_lock();
1962                                         lttng_ht_add_unique_ulong(relay_connections_ht,
1963                                                         &conn->sock_n);
1964                                         rcu_read_unlock();
1965                                         DBG("Connection socket %d added", conn->sock->fd);
1966                                 }
1967                         } else {
1968                                 rcu_read_lock();
1969                                 conn = connection_find_by_sock(relay_connections_ht, pollfd);
1970                                 /* If not found, there is a synchronization issue. */
1971                                 assert(conn);
1972
1973                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1974                                         cleanup_connection_pollfd(&events, pollfd);
1975                                         destroy_connection(relay_connections_ht, conn);
1976                                 } else if (revents & LPOLLIN) {
1977                                         ret = conn->sock->ops->recvmsg(conn->sock, &recv_hdr,
1978                                                         sizeof(recv_hdr), 0);
1979                                         if (ret <= 0) {
1980                                                 /* Connection closed */
1981                                                 cleanup_connection_pollfd(&events, pollfd);
1982                                                 destroy_connection(relay_connections_ht, conn);
1983                                                 DBG("Viewer control conn closed with %d", pollfd);
1984                                         } else {
1985                                                 ret = process_control(&recv_hdr, conn);
1986                                                 if (ret < 0) {
1987                                                         /* Clear the session on error. */
1988                                                         cleanup_connection_pollfd(&events, pollfd);
1989                                                         destroy_connection(relay_connections_ht, conn);
1990                                                         DBG("Viewer connection closed with %d", pollfd);
1991                                                 }
1992                                         }
1993                                 }
1994                                 rcu_read_unlock();
1995                         }
1996                 }
1997         }
1998
1999 exit:
2000 error:
2001         lttng_poll_clean(&events);
2002
2003         /* Cleanup reamaining connection object. */
2004         rcu_read_lock();
2005         cds_lfht_for_each_entry(relay_connections_ht->ht, &iter.iter, conn,
2006                         sock_n.node) {
2007                 health_code_update();
2008                 destroy_connection(relay_connections_ht, conn);
2009         }
2010         rcu_read_unlock();
2011 error_poll_create:
2012         lttng_ht_destroy(relay_connections_ht);
2013 relay_connections_ht_error:
2014         /* Close relay conn pipes */
2015         utils_close_pipe(live_conn_pipe);
2016         if (err) {
2017                 DBG("Viewer worker thread exited with error");
2018         }
2019         DBG("Viewer worker thread cleanup complete");
2020 error_testpoint:
2021         if (err) {
2022                 health_error();
2023                 ERR("Health error occurred in %s", __func__);
2024         }
2025         health_unregister(health_relayd);
2026         if (lttng_relay_stop_threads()) {
2027                 ERR("Error stopping threads");
2028         }
2029         rcu_unregister_thread();
2030         return NULL;
2031 }
2032
2033 /*
2034  * Create the relay command pipe to wake thread_manage_apps.
2035  * Closed in cleanup().
2036  */
2037 static int create_conn_pipe(void)
2038 {
2039         return utils_create_pipe_cloexec(live_conn_pipe);
2040 }
2041
2042 int relayd_live_join(void)
2043 {
2044         int ret, retval = 0;
2045         void *status;
2046
2047         ret = pthread_join(live_listener_thread, &status);
2048         if (ret) {
2049                 errno = ret;
2050                 PERROR("pthread_join live listener");
2051                 retval = -1;
2052         }
2053
2054         ret = pthread_join(live_worker_thread, &status);
2055         if (ret) {
2056                 errno = ret;
2057                 PERROR("pthread_join live worker");
2058                 retval = -1;
2059         }
2060
2061         ret = pthread_join(live_dispatcher_thread, &status);
2062         if (ret) {
2063                 errno = ret;
2064                 PERROR("pthread_join live dispatcher");
2065                 retval = -1;
2066         }
2067
2068         cleanup_relayd_live();
2069
2070         return retval;
2071 }
2072
2073 /*
2074  * main
2075  */
2076 int relayd_live_create(struct lttng_uri *uri,
2077                 struct relay_local_data *relay_ctx)
2078 {
2079         int ret = 0, retval = 0;
2080         void *status;
2081         int is_root;
2082
2083         if (!uri) {
2084                 retval = -1;
2085                 goto exit_init_data;
2086         }
2087         live_uri = uri;
2088
2089         /* Check if daemon is UID = 0 */
2090         is_root = !getuid();
2091
2092         if (!is_root) {
2093                 if (live_uri->port < 1024) {
2094                         ERR("Need to be root to use ports < 1024");
2095                         retval = -1;
2096                         goto exit_init_data;
2097                 }
2098         }
2099
2100         /* Setup the thread apps communication pipe. */
2101         if (create_conn_pipe()) {
2102                 retval = -1;
2103                 goto exit_init_data;
2104         }
2105
2106         /* Init relay command queue. */
2107         cds_wfcq_init(&viewer_conn_queue.head, &viewer_conn_queue.tail);
2108
2109         /* Set up max poll set size */
2110         if (lttng_poll_set_max_size()) {
2111                 retval = -1;
2112                 goto exit_init_data;
2113         }
2114
2115         /* Setup the dispatcher thread */
2116         ret = pthread_create(&live_dispatcher_thread, NULL,
2117                         thread_dispatcher, (void *) NULL);
2118         if (ret) {
2119                 errno = ret;
2120                 PERROR("pthread_create viewer dispatcher");
2121                 retval = -1;
2122                 goto exit_dispatcher_thread;
2123         }
2124
2125         /* Setup the worker thread */
2126         ret = pthread_create(&live_worker_thread, NULL,
2127                         thread_worker, relay_ctx);
2128         if (ret) {
2129                 errno = ret;
2130                 PERROR("pthread_create viewer worker");
2131                 retval = -1;
2132                 goto exit_worker_thread;
2133         }
2134
2135         /* Setup the listener thread */
2136         ret = pthread_create(&live_listener_thread, NULL,
2137                         thread_listener, (void *) NULL);
2138         if (ret) {
2139                 errno = ret;
2140                 PERROR("pthread_create viewer listener");
2141                 retval = -1;
2142                 goto exit_listener_thread;
2143         }
2144
2145         /*
2146          * All OK, started all threads.
2147          */
2148         return retval;
2149
2150         /*
2151          * Join on the live_listener_thread should anything be added after
2152          * the live_listener thread's creation.
2153          */
2154
2155 exit_listener_thread:
2156
2157         ret = pthread_join(live_worker_thread, &status);
2158         if (ret) {
2159                 errno = ret;
2160                 PERROR("pthread_join live worker");
2161                 retval = -1;
2162         }
2163 exit_worker_thread:
2164
2165         ret = pthread_join(live_dispatcher_thread, &status);
2166         if (ret) {
2167                 errno = ret;
2168                 PERROR("pthread_join live dispatcher");
2169                 retval = -1;
2170         }
2171 exit_dispatcher_thread:
2172
2173 exit_init_data:
2174         cleanup_relayd_live();
2175
2176         return retval;
2177 }