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