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(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 /*
 330  * Write to writable pipe used to notify a thread.
 331  */
 332 static
 333 int notify_thread_pipe(int wpipe)
 334 {
 335         ssize_t ret;
 336
 337         ret = lttng_write(wpipe, "!", 1);
 338         if (ret < 1) {
 339                 PERROR("write poll pipe");
 340         }
 341
 342         return (int) ret;
 343 }
 344
 345 /*
 346  * Stop all threads by closing the thread quit pipe.
 347  */
 348 static
 349 void stop_threads(void)
 350 {
 351         int ret;
 352
 353         /* Stopping all threads */
 354         DBG("Terminating all live threads");
 355         ret = notify_thread_pipe(thread_quit_pipe[1]);
 356         if (ret < 0) {
 357                 ERR("write error on thread quit pipe");
 358         }
 359
 360         /* Dispatch thread */
 361         CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
 362         futex_nto1_wake(&viewer_conn_queue.futex);
 363 }
 364
 365 /*
 366  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 367  */
 368 static
 369 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 370 {
 371         int ret;
 372
 373         if (events == NULL || size == 0) {
 374                 ret = -1;
 375                 goto error;
 376         }
 377
 378         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 379         if (ret < 0) {
 380                 goto error;
 381         }
 382
 383         /* Add quit pipe */
 384         ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
 385         if (ret < 0) {
 386                 goto error;
 387         }
 388
 389         return 0;
 390
 391 error:
 392         return ret;
 393 }
 394
 395 /*
 396  * Check if the thread quit pipe was triggered.
 397  *
 398  * Return 1 if it was triggered else 0;
 399  */
 400 static
 401 int check_thread_quit_pipe(int fd, uint32_t events)
 402 {
 403         if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
 404                 return 1;
 405         }
 406
 407         return 0;
 408 }
 409
 410 /*
 411  * Create and init socket from uri.
 412  */
 413 static
 414 struct lttcomm_sock *init_socket(struct lttng_uri *uri)
 415 {
 416         int ret;
 417         struct lttcomm_sock *sock = NULL;
 418
 419         sock = lttcomm_alloc_sock_from_uri(uri);
 420         if (sock == NULL) {
 421                 ERR("Allocating socket");
 422                 goto error;
 423         }
 424
 425         ret = lttcomm_create_sock(sock);
 426         if (ret < 0) {
 427                 goto error;
 428         }
 429         DBG("Listening on sock %d for live", sock->fd);
 430
 431         ret = sock->ops->bind(sock);
 432         if (ret < 0) {
 433                 goto error;
 434         }
 435
 436         ret = sock->ops->listen(sock, -1);
 437         if (ret < 0) {
 438                 goto error;
 439
 440         }
 441
 442         return sock;
 443
 444 error:
 445         if (sock) {
 446                 lttcomm_destroy_sock(sock);
 447         }
 448         return NULL;
 449 }
 450
 451 /*
 452  * This thread manages the listening for new connections on the network
 453  */
 454 static
 455 void *thread_listener(void *data)
 456 {
 457         int i, ret, pollfd, err = -1;
 458         uint32_t revents, nb_fd;
 459         struct lttng_poll_event events;
 460         struct lttcomm_sock *live_control_sock;
 461
 462         DBG("[thread] Relay live listener started");
 463
 464         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_LISTENER);
 465
 466         health_code_update();
 467
 468         live_control_sock = init_socket(live_uri);
 469         if (!live_control_sock) {
 470                 goto error_sock_control;
 471         }
 472
 473         /* Pass 2 as size here for the thread quit pipe and control sockets. */
 474         ret = create_thread_poll_set(&events, 2);
 475         if (ret < 0) {
 476                 goto error_create_poll;
 477         }
 478
 479         /* Add the control socket */
 480         ret = lttng_poll_add(&events, live_control_sock->fd, LPOLLIN | LPOLLRDHUP);
 481         if (ret < 0) {
 482                 goto error_poll_add;
 483         }
 484
 485         lttng_relay_notify_ready();
 486
 487         if (testpoint(relayd_thread_live_listener)) {
 488                 goto error_testpoint;
 489         }
 490
 491         while (1) {
 492                 health_code_update();
 493
 494                 DBG("Listener accepting live viewers connections");
 495
 496 restart:
 497                 health_poll_entry();
 498                 ret = lttng_poll_wait(&events, -1);
 499                 health_poll_exit();
 500                 if (ret < 0) {
 501                         /*
 502                          * Restart interrupted system call.
 503                          */
 504                         if (errno == EINTR) {
 505                                 goto restart;
 506                         }
 507                         goto error;
 508                 }
 509                 nb_fd = ret;
 510
 511                 DBG("Relay new viewer connection received");
 512                 for (i = 0; i < nb_fd; i++) {
 513                         health_code_update();
 514
 515                         /* Fetch once the poll data */
 516                         revents = LTTNG_POLL_GETEV(&events, i);
 517                         pollfd = LTTNG_POLL_GETFD(&events, i);
 518
 519                         /* Thread quit pipe has been closed. Killing thread. */
 520                         ret = check_thread_quit_pipe(pollfd, revents);
 521                         if (ret) {
 522                                 err = 0;
 523                                 goto exit;
 524                         }
 525
 526                         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 527                                 ERR("socket poll error");
 528                                 goto error;
 529                         } else if (revents & LPOLLIN) {
 530                                 /*
 531                                  * Get allocated in this thread, enqueued to a global queue,
 532                                  * dequeued and freed in the worker thread.
 533                                  */
 534                                 int val = 1;
 535                                 struct relay_connection *new_conn;
 536                                 struct lttcomm_sock *newsock;
 537
 538                                 new_conn = connection_create();
 539                                 if (!new_conn) {
 540                                         goto error;
 541                                 }
 542
 543                                 newsock = live_control_sock->ops->accept(live_control_sock);
 544                                 if (!newsock) {
 545                                         PERROR("accepting control sock");
 546                                         connection_free(new_conn);
 547                                         goto error;
 548                                 }
 549                                 DBG("Relay viewer connection accepted socket %d", newsock->fd);
 550
 551                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR, &val,
 552                                                 sizeof(val));
 553                                 if (ret < 0) {
 554                                         PERROR("setsockopt inet");
 555                                         lttcomm_destroy_sock(newsock);
 556                                         connection_free(new_conn);
 557                                         goto error;
 558                                 }
 559                                 new_conn->sock = newsock;
 560
 561                                 /* Enqueue request for the dispatcher thread. */
 562                                 cds_wfcq_enqueue(&viewer_conn_queue.head, &viewer_conn_queue.tail,
 563                                                  &new_conn->qnode);
 564
 565                                 /*
 566                                  * Wake the dispatch queue futex. Implicit memory barrier with
 567                                  * the exchange in cds_wfcq_enqueue.
 568                                  */
 569                                 futex_nto1_wake(&viewer_conn_queue.futex);
 570                         }
 571                 }
 572         }
 573
 574 exit:
 575 error:
 576 error_poll_add:
 577 error_testpoint:
 578         lttng_poll_clean(&events);
 579 error_create_poll:
 580         if (live_control_sock->fd >= 0) {
 581                 ret = live_control_sock->ops->close(live_control_sock);
 582                 if (ret) {
 583                         PERROR("close");
 584                 }
 585         }
 586         lttcomm_destroy_sock(live_control_sock);
 587 error_sock_control:
 588         if (err) {
 589                 health_error();
 590                 DBG("Live viewer listener thread exited with error");
 591         }
 592         health_unregister(health_relayd);
 593         DBG("Live viewer listener thread cleanup complete");
 594         stop_threads();
 595         return NULL;
 596 }
 597
 598 /*
 599  * This thread manages the dispatching of the requests to worker threads
 600  */
 601 static
 602 void *thread_dispatcher(void *data)
 603 {
 604         int err = -1;
 605         ssize_t ret;
 606         struct cds_wfcq_node *node;
 607         struct relay_connection *conn = NULL;
 608
 609         DBG("[thread] Live viewer relay dispatcher started");
 610
 611         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 612
 613         if (testpoint(relayd_thread_live_dispatcher)) {
 614                 goto error_testpoint;
 615         }
 616
 617         health_code_update();
 618
 619         while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 620                 health_code_update();
 621
 622                 /* Atomically prepare the queue futex */
 623                 futex_nto1_prepare(&viewer_conn_queue.futex);
 624
 625                 do {
 626                         health_code_update();
 627
 628                         /* Dequeue commands */
 629                         node = cds_wfcq_dequeue_blocking(&viewer_conn_queue.head,
 630                                                          &viewer_conn_queue.tail);
 631                         if (node == NULL) {
 632                                 DBG("Woken up but nothing in the live-viewer "
 633                                                 "relay command queue");
 634                                 /* Continue thread execution */
 635                                 break;
 636                         }
 637                         conn = caa_container_of(node, struct relay_connection, qnode);
 638                         DBG("Dispatching viewer request waiting on sock %d",
 639                                         conn->sock->fd);
 640
 641                         /*
 642                          * Inform worker thread of the new request. This call is blocking
 643                          * so we can be assured that the data will be read at some point in
 644                          * time or wait to the end of the world :)
 645                          */
 646                         ret = lttng_write(live_conn_pipe[1], &conn, sizeof(conn));
 647                         if (ret < 0) {
 648                                 PERROR("write conn pipe");
 649                                 connection_destroy(conn);
 650                                 goto error;
 651                         }
 652                 } while (node != NULL);
 653
 654                 /* Futex wait on queue. Blocking call on futex() */
 655                 health_poll_entry();
 656                 futex_nto1_wait(&viewer_conn_queue.futex);
 657                 health_poll_exit();
 658         }
 659
 660         /* Normal exit, no error */
 661         err = 0;
 662
 663 error:
 664 error_testpoint:
 665         if (err) {
 666                 health_error();
 667                 ERR("Health error occurred in %s", __func__);
 668         }
 669         health_unregister(health_relayd);
 670         DBG("Live viewer dispatch thread dying");
 671         stop_threads();
 672         return NULL;
 673 }
 674
 675 /*
 676  * Establish connection with the viewer and check the versions.
 677  *
 678  * Return 0 on success or else negative value.
 679  */
 680 static
 681 int viewer_connect(struct relay_connection *conn)
 682 {
 683         int ret;
 684         struct lttng_viewer_connect reply, msg;
 685
 686         assert(conn);
 687
 688         conn->version_check_done = 1;
 689
 690         health_code_update();
 691
 692         DBG("Viewer is establishing a connection to the relayd.");
 693
 694         ret = recv_request(conn->sock, &msg, sizeof(msg));
 695         if (ret < 0) {
 696                 goto end;
 697         }
 698
 699         health_code_update();
 700
 701         memset(&reply, 0, sizeof(reply));
 702         reply.major = RELAYD_VERSION_COMM_MAJOR;
 703         reply.minor = RELAYD_VERSION_COMM_MINOR;
 704
 705         /* Major versions must be the same */
 706         if (reply.major != be32toh(msg.major)) {
 707                 DBG("Incompatible major versions ([relayd] %u vs [client] %u)",
 708                                 reply.major, be32toh(msg.major));
 709                 ret = -1;
 710                 goto end;
 711         }
 712
 713         conn->major = reply.major;
 714         /* We adapt to the lowest compatible version */
 715         if (reply.minor <= be32toh(msg.minor)) {
 716                 conn->minor = reply.minor;
 717         } else {
 718                 conn->minor = be32toh(msg.minor);
 719         }
 720
 721         if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_COMMAND) {
 722                 conn->type = RELAY_VIEWER_COMMAND;
 723         } else if (be32toh(msg.type) == LTTNG_VIEWER_CLIENT_NOTIFICATION) {
 724                 conn->type = RELAY_VIEWER_NOTIFICATION;
 725         } else {
 726                 ERR("Unknown connection type : %u", be32toh(msg.type));
 727                 ret = -1;
 728                 goto end;
 729         }
 730
 731         reply.major = htobe32(reply.major);
 732         reply.minor = htobe32(reply.minor);
 733         if (conn->type == RELAY_VIEWER_COMMAND) {
 734                 reply.viewer_session_id = htobe64(++last_relay_viewer_session_id);
 735         }
 736
 737         health_code_update();
 738
 739         ret = send_response(conn->sock, &reply, sizeof(reply));
 740         if (ret < 0) {
 741                 goto end;
 742         }
 743
 744         health_code_update();
 745
 746         DBG("Version check done using protocol %u.%u", conn->major, conn->minor);
 747         ret = 0;
 748
 749 end:
 750         return ret;
 751 }
 752
 753 /*
 754  * Send the viewer the list of current sessions.
 755  *
 756  * Return 0 on success or else a negative value.
 757  */
 758 static
 759 int viewer_list_sessions(struct relay_connection *conn)
 760 {
 761         int ret;
 762         struct lttng_viewer_list_sessions session_list;
 763         unsigned long count;
 764         long approx_before, approx_after;
 765         struct lttng_ht_iter iter;
 766         struct lttng_viewer_session send_session;
 767         struct relay_session *session;
 768
 769         DBG("List sessions received");
 770
 771         rcu_read_lock();
 772         cds_lfht_count_nodes(conn->sessions_ht->ht, &approx_before, &count,
 773                         &approx_after);
 774         session_list.sessions_count = htobe32(count);
 775
 776         health_code_update();
 777
 778         ret = send_response(conn->sock, &session_list, sizeof(session_list));
 779         if (ret < 0) {
 780                 goto end_unlock;
 781         }
 782
 783         health_code_update();
 784
 785         cds_lfht_for_each_entry(conn->sessions_ht->ht, &iter.iter, session,
 786                         session_n.node) {
 787                 health_code_update();
 788
 789                 strncpy(send_session.session_name, session->session_name,
 790                                 sizeof(send_session.session_name));
 791                 strncpy(send_session.hostname, session->hostname,
 792                                 sizeof(send_session.hostname));
 793                 send_session.id = htobe64(session->id);
 794                 send_session.live_timer = htobe32(session->live_timer);
 795                 send_session.clients = htobe32(session->viewer_refcount);
 796                 send_session.streams = htobe32(session->stream_count);
 797
 798                 health_code_update();
 799
 800                 ret = send_response(conn->sock, &send_session, sizeof(send_session));
 801                 if (ret < 0) {
 802                         goto end_unlock;
 803                 }
 804         }
 805         health_code_update();
 806
 807         rcu_read_unlock();
 808         ret = 0;
 809         goto end;
 810
 811 end_unlock:
 812         rcu_read_unlock();
 813
 814 end:
 815         return ret;
 816 }
 817
 818 /*
 819  * Check if a connection is attached to a session.
 820  * Return 1 if attached, 0 if not attached, a negative value on error.
 821  */
 822 static
 823 int session_attached(struct relay_connection *conn, uint64_t session_id)
 824 {
 825         struct relay_session *session;
 826         int found = 0;
 827
 828         if (!conn->viewer_session) {
 829                 goto end;
 830         }
 831         cds_list_for_each_entry(session,
 832                         &conn->viewer_session->sessions_head,
 833                         viewer_session_list) {
 834                 if (session->id == session_id) {
 835                         found = 1;
 836                         goto end;
 837                 }
 838         }
 839
 840 end:
 841         return found;
 842 }
 843
 844 /*
 845  * Delete all streams for a specific session ID.
 846  */
 847 static void destroy_viewer_streams_by_session(struct relay_session *session)
 848 {
 849         struct relay_viewer_stream *stream;
 850         struct lttng_ht_iter iter;
 851
 852         assert(session);
 853
 854         rcu_read_lock();
 855         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, stream,
 856                         stream_n.node) {
 857                 struct ctf_trace *ctf_trace;
 858
 859                 health_code_update();
 860                 if (stream->session_id != session->id) {
 861                         continue;
 862                 }
 863
 864                 ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
 865                                 stream->path_name);
 866                 assert(ctf_trace);
 867
 868                 viewer_stream_delete(stream);
 869
 870                 if (stream->metadata_flag) {
 871                         ctf_trace->metadata_sent = 0;
 872                         ctf_trace->viewer_metadata_stream = NULL;
 873                 }
 874
 875                 viewer_stream_destroy(ctf_trace, stream);
 876         }
 877         rcu_read_unlock();
 878 }
 879
 880 static void try_destroy_streams(struct relay_session *session)
 881 {
 882         struct ctf_trace *ctf_trace;
 883         struct lttng_ht_iter iter;
 884
 885         assert(session);
 886
 887         cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
 888                         node.node) {
 889                 /* Attempt to destroy the ctf trace of that session. */
 890                 ctf_trace_try_destroy(session, ctf_trace);
 891         }
 892 }
 893
 894 /*
 895  * Cleanup a session.
 896  */
 897 static void cleanup_session(struct relay_connection *conn,
 898                 struct relay_session *session)
 899 {
 900         /*
 901          * Very important that this is done before destroying the session so we
 902          * can put back every viewer stream reference from the ctf_trace.
 903          */
 904         destroy_viewer_streams_by_session(session);
 905         try_destroy_streams(session);
 906         cds_list_del(&session->viewer_session_list);
 907         session_viewer_try_destroy(conn->sessions_ht, session);
 908 }
 909
 910 /*
 911  * Send the viewer the list of current sessions.
 912  */
 913 static
 914 int viewer_get_new_streams(struct relay_connection *conn)
 915 {
 916         int ret, send_streams = 0;
 917         uint32_t nb_created = 0, nb_unsent = 0, nb_streams = 0;
 918         struct lttng_viewer_new_streams_request request;
 919         struct lttng_viewer_new_streams_response response;
 920         struct relay_session *session;
 921         uint64_t session_id;
 922
 923         assert(conn);
 924
 925         DBG("Get new streams received");
 926
 927         health_code_update();
 928
 929         /* Receive the request from the connected client. */
 930         ret = recv_request(conn->sock, &request, sizeof(request));
 931         if (ret < 0) {
 932                 goto error;
 933         }
 934         session_id = be64toh(request.session_id);
 935
 936         health_code_update();
 937
 938         memset(&response, 0, sizeof(response));
 939
 940         rcu_read_lock();
 941         session = session_find_by_id(conn->sessions_ht, session_id);
 942         if (!session) {
 943                 DBG("Relay session %" PRIu64 " not found", session_id);
 944                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 945                 goto send_reply;
 946         }
 947
 948         if (!session_attached(conn, session_id)) {
 949                 send_streams = 0;
 950                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_ERR);
 951                 goto send_reply;
 952         }
 953
 954         send_streams = 1;
 955         response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_OK);
 956
 957         ret = make_viewer_streams(session, LTTNG_VIEWER_SEEK_LAST, NULL, &nb_unsent,
 958                         &nb_created);
 959         if (ret < 0) {
 960                 goto end_unlock;
 961         }
 962         /* Only send back the newly created streams with the unsent ones. */
 963         nb_streams = nb_created + nb_unsent;
 964         response.streams_count = htobe32(nb_streams);
 965
 966         /*
 967          * If the session is closed and we have no new streams to send,
 968          * it means that the viewer has already received the whole trace
 969          * for this session and should now close it.
 970          */
 971         if (nb_streams == 0 && session->close_flag) {
 972                 send_streams = 0;
 973                 response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_HUP);
 974                 /*
 975                  * Remove the session from the attached list of the connection
 976                  * and try to destroy it.
 977                  */
 978                 cds_list_del(&session->viewer_session_list);
 979                 cleanup_session(conn, session);
 980                 goto send_reply;
 981         }
 982
 983 send_reply:
 984         health_code_update();
 985         ret = send_response(conn->sock, &response, sizeof(response));
 986         if (ret < 0) {
 987                 goto end_unlock;
 988         }
 989         health_code_update();
 990
 991         /*
 992          * Unknown or empty session, just return gracefully, the viewer knows what
 993          * is happening.
 994          */
 995         if (!send_streams || !nb_streams) {
 996                 ret = 0;
 997                 goto end_unlock;
 998         }
 999
1000         /*
1001          * Send stream and *DON'T* ignore the sent flag so every viewer streams
1002          * that were not sent from that point will be sent to the viewer.
1003          */
1004         ret = send_viewer_streams(conn->sock, session, 0);
1005         if (ret < 0) {
1006                 goto end_unlock;
1007         }
1008
1009 end_unlock:
1010         rcu_read_unlock();
1011 error:
1012         return ret;
1013 }
1014
1015 /*
1016  * Send the viewer the list of current sessions.
1017  */
1018 static
1019 int viewer_attach_session(struct relay_connection *conn)
1020 {
1021         int send_streams = 0;
1022         ssize_t ret;
1023         uint32_t nb_streams = 0;
1024         enum lttng_viewer_seek seek_type;
1025         struct lttng_viewer_attach_session_request request;
1026         struct lttng_viewer_attach_session_response response;
1027         struct relay_session *session;
1028
1029         assert(conn);
1030
1031         health_code_update();
1032
1033         /* Receive the request from the connected client. */
1034         ret = recv_request(conn->sock, &request, sizeof(request));
1035         if (ret < 0) {
1036                 goto error;
1037         }
1038
1039         health_code_update();
1040
1041         memset(&response, 0, sizeof(response));
1042
1043         if (!conn->viewer_session) {
1044                 DBG("Client trying to attach before creating a live viewer session");
1045                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NO_SESSION);
1046                 goto send_reply;
1047         }
1048
1049         rcu_read_lock();
1050         session = session_find_by_id(conn->sessions_ht,
1051                         be64toh(request.session_id));
1052         if (!session) {
1053                 DBG("Relay session %" PRIu64 " not found",
1054                                 be64toh(request.session_id));
1055                 response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
1056                 goto send_reply;
1057         }
1058         session_viewer_attach(session);
1059         DBG("Attach session ID %" PRIu64 " received", be64toh(request.session_id));
1060
1061         if (uatomic_read(&session->viewer_refcount) > 1) {
1062                 DBG("Already a viewer attached");
1063                 response.status = htobe32(LTTNG_VIEWER_ATTACH_ALREADY);
1064                 session_viewer_detach(session);
1065                 goto send_reply;
1066         } else if (session->live_timer == 0) {
1067                 DBG("Not live session");
1068                 response.status = htobe32(LTTNG_VIEWER_ATTACH_NOT_LIVE);
1069                 goto send_reply;
1070         } else {
1071                 send_streams = 1;
1072                 response.status = htobe32(LTTNG_VIEWER_ATTACH_OK);
1073                 cds_list_add(&session->viewer_session_list,
1074                                 &conn->viewer_session->sessions_head);
1075         }
1076
1077         switch (be32toh(request.seek)) {
1078         case LTTNG_VIEWER_SEEK_BEGINNING:
1079         case LTTNG_VIEWER_SEEK_LAST:
1080                 seek_type = be32toh(request.seek);
1081                 break;
1082         default:
1083                 ERR("Wrong seek parameter");
1084                 response.status = htobe32(LTTNG_VIEWER_ATTACH_SEEK_ERR);
1085                 send_streams = 0;
1086                 goto send_reply;
1087         }
1088
1089         ret = make_viewer_streams(session, seek_type, &nb_streams, NULL, NULL);
1090         if (ret < 0) {
1091                 goto end_unlock;
1092         }
1093         response.streams_count = htobe32(nb_streams);
1094
1095 send_reply:
1096         health_code_update();
1097         ret = send_response(conn->sock, &response, sizeof(response));
1098         if (ret < 0) {
1099                 goto end_unlock;
1100         }
1101         health_code_update();
1102
1103         /*
1104          * Unknown or empty session, just return gracefully, the viewer knows what
1105          * is happening.
1106          */
1107         if (!send_streams || !nb_streams) {
1108                 ret = 0;
1109                 goto end_unlock;
1110         }
1111
1112         /* Send stream and ignore the sent flag. */
1113         ret = send_viewer_streams(conn->sock, session, 1);
1114         if (ret < 0) {
1115                 goto end_unlock;
1116         }
1117
1118 end_unlock:
1119         rcu_read_unlock();
1120 error:
1121         return ret;
1122 }
1123
1124 /*
1125  * Open the index file if needed for the given vstream.
1126  *
1127  * If an index file is successfully opened, the index_read_fd of the stream is
1128  * set with it.
1129  *
1130  * Return 0 on success, a negative value on error (-ENOENT if not ready yet).
1131  */
1132 static int try_open_index(struct relay_viewer_stream *vstream,
1133                 struct relay_stream *rstream)
1134 {
1135         int ret = 0;
1136
1137         assert(vstream);
1138         assert(rstream);
1139
1140         if (vstream->index_read_fd >= 0) {
1141                 goto end;
1142         }
1143
1144         /*
1145          * First time, we open the index file and at least one index is ready.  The
1146          * race between the read and write of the total_index_received is
1147          * acceptable here since the client will be notified to simply come back
1148          * and get the next index.
1149          */
1150         if (rstream->total_index_received <= 0) {
1151                 ret = -ENOENT;
1152                 goto end;
1153         }
1154         ret = index_open(vstream->path_name, vstream->channel_name,
1155                         vstream->tracefile_count, vstream->tracefile_count_current);
1156         if (ret >= 0) {
1157                 vstream->index_read_fd = ret;
1158                 ret = 0;
1159                 goto end;
1160         }
1161
1162 end:
1163         return ret;
1164 }
1165
1166 /*
1167  * Check the status of the index for the given stream. This function updates
1168  * the index structure if needed and can destroy the vstream also for the HUP
1169  * situation.
1170  *
1171  * Return 0 means that we can proceed with the index. A value of 1 means that
1172  * the index has been updated and is ready to be send to the client. A negative
1173  * value indicates an error that can't be handled.
1174  */
1175 static int check_index_status(struct relay_viewer_stream *vstream,
1176                 struct relay_stream *rstream, struct ctf_trace *trace,
1177                 struct lttng_viewer_index *index)
1178 {
1179         int ret;
1180
1181         assert(vstream);
1182         assert(rstream);
1183         assert(index);
1184         assert(trace);
1185
1186         if (!rstream->close_flag) {
1187                 /* Rotate on abort (overwrite). */
1188                 if (vstream->abort_flag) {
1189                         DBG("Viewer stream %" PRIu64 " rotate because of overwrite",
1190                                         vstream->stream_handle);
1191                         ret = viewer_stream_rotate(vstream, rstream);
1192                         if (ret < 0) {
1193                                 goto error;
1194                         } else if (ret == 1) {
1195                                 /* EOF */
1196                                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1197                                 goto hup;
1198                         }
1199                         /* ret == 0 means successful so we continue. */
1200                 }
1201
1202                 /* Check if we are in the same trace file at this point. */
1203                 if (rstream->tracefile_count_current == vstream->tracefile_count_current) {
1204                         if (rstream->beacon_ts_end != -1ULL &&
1205                                         vstream->last_sent_index == rstream->total_index_received) {
1206                                 /*
1207                                  * We've received a synchronization beacon and the last index
1208                                  * available has been sent, the index for now is inactive.
1209                                  */
1210                                 index->status = htobe32(LTTNG_VIEWER_INDEX_INACTIVE);
1211                                 index->timestamp_end = htobe64(rstream->beacon_ts_end);
1212                                 index->stream_id = htobe64(rstream->ctf_stream_id);
1213                                 goto index_ready;
1214                         } else if (rstream->total_index_received <= vstream->last_sent_index
1215                                         && !vstream->close_write_flag) {
1216                                 /*
1217                                  * Reader and writer are working in the same tracefile, so we care
1218                                  * about the number of index received and sent. Otherwise, we read
1219                                  * up to EOF.
1220                                  */
1221                                 index->status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1222                                 goto index_ready;
1223                         }
1224                 }
1225                 /* Nothing to do with the index, continue with it. */
1226                 ret = 0;
1227         } else if (rstream->close_flag && vstream->close_write_flag &&
1228                         vstream->total_index_received == vstream->last_sent_index) {
1229                 /* Last index sent and current tracefile closed in write */
1230                 index->status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1231                 goto hup;
1232         } else {
1233                 vstream->close_write_flag = 1;
1234                 ret = 0;
1235         }
1236
1237 error:
1238         return ret;
1239
1240 hup:
1241         viewer_stream_delete(vstream);
1242         viewer_stream_destroy(trace, vstream);
1243 index_ready:
1244         return 1;
1245 }
1246
1247 /*
1248  * Send the next index for a stream.
1249  *
1250  * Return 0 on success or else a negative value.
1251  */
1252 static
1253 int viewer_get_next_index(struct relay_connection *conn)
1254 {
1255         int ret;
1256         ssize_t read_ret;
1257         struct lttng_viewer_get_next_index request_index;
1258         struct lttng_viewer_index viewer_index;
1259         struct ctf_packet_index packet_index;
1260         struct relay_viewer_stream *vstream;
1261         struct relay_stream *rstream;
1262         struct ctf_trace *ctf_trace;
1263         struct relay_session *session;
1264
1265         assert(conn);
1266
1267         DBG("Viewer get next index");
1268
1269         health_code_update();
1270
1271         ret = recv_request(conn->sock, &request_index, sizeof(request_index));
1272         if (ret < 0) {
1273                 goto end;
1274         }
1275         health_code_update();
1276
1277         rcu_read_lock();
1278         vstream = viewer_stream_find_by_id(be64toh(request_index.stream_id));
1279         if (!vstream) {
1280                 ret = -1;
1281                 goto end_unlock;
1282         }
1283
1284         session = session_find_by_id(conn->sessions_ht, vstream->session_id);
1285         if (!session) {
1286                 ret = -1;
1287                 goto end_unlock;
1288         }
1289
1290         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht, vstream->path_name);
1291         assert(ctf_trace);
1292
1293         memset(&viewer_index, 0, sizeof(viewer_index));
1294
1295         /*
1296          * The viewer should not ask for index on metadata stream.
1297          */
1298         if (vstream->metadata_flag) {
1299                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1300                 goto send_reply;
1301         }
1302
1303         rstream = stream_find_by_id(relay_streams_ht, vstream->stream_handle);
1304         assert(rstream);
1305
1306         /* Try to open an index if one is needed for that stream. */
1307         ret = try_open_index(vstream, rstream);
1308         if (ret < 0) {
1309                 if (ret == -ENOENT) {
1310                         /*
1311                          * The index is created only when the first data packet arrives, it
1312                          * might not be ready at the beginning of the session
1313                          */
1314                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1315                 } else {
1316                         /* Unhandled error. */
1317                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1318                 }
1319                 goto send_reply;
1320         }
1321
1322         pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1323         ret = check_index_status(vstream, rstream, ctf_trace, &viewer_index);
1324         pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1325         if (ret < 0) {
1326                 goto end_unlock;
1327         } else if (ret == 1) {
1328                 /*
1329                  * This means the viewer index data structure has been populated by the
1330                  * check call thus we now send back the reply to the client.
1331                  */
1332                 goto send_reply;
1333         }
1334         /* At this point, ret MUST be 0 thus we continue with the get. */
1335         assert(!ret);
1336
1337         if (!ctf_trace->metadata_received ||
1338                         ctf_trace->metadata_received > ctf_trace->metadata_sent) {
1339                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1340         }
1341
1342         ret = check_new_streams(conn);
1343         if (ret < 0) {
1344                 goto end_unlock;
1345         } else if (ret == 1) {
1346                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1347         }
1348
1349         pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1350         pthread_mutex_lock(&vstream->overwrite_lock);
1351         if (vstream->abort_flag) {
1352                 /* The file is being overwritten by the writer, we cannot use it. */
1353                 pthread_mutex_unlock(&vstream->overwrite_lock);
1354                 ret = viewer_stream_rotate(vstream, rstream);
1355                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1356                 if (ret < 0) {
1357                         goto end_unlock;
1358                 } else if (ret == 1) {
1359                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1360                         viewer_stream_delete(vstream);
1361                         viewer_stream_destroy(ctf_trace, vstream);
1362                 } else {
1363                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1364                 }
1365                 goto send_reply;
1366         }
1367
1368         read_ret = lttng_read(vstream->index_read_fd, &packet_index,
1369                         sizeof(packet_index));
1370         pthread_mutex_unlock(&vstream->overwrite_lock);
1371         pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1372         if (read_ret < 0) {
1373                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1374                 viewer_stream_delete(vstream);
1375                 viewer_stream_destroy(ctf_trace, vstream);
1376                 goto send_reply;
1377         } else if (read_ret < sizeof(packet_index)) {
1378                 pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1379                 if (vstream->close_write_flag) {
1380                         ret = viewer_stream_rotate(vstream, rstream);
1381                         if (ret < 0) {
1382                                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1383                                 goto end_unlock;
1384                         } else if (ret == 1) {
1385                                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_HUP);
1386                                 viewer_stream_delete(vstream);
1387                                 viewer_stream_destroy(ctf_trace, vstream);
1388                         } else {
1389                                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
1390                         }
1391                 } else {
1392                         ERR("Relay reading index file %d", vstream->index_read_fd);
1393                         viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
1394                 }
1395                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1396                 goto send_reply;
1397         } else {
1398                 viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_OK);
1399                 vstream->last_sent_index++;
1400         }
1401
1402         /*
1403          * Indexes are stored in big endian, no need to switch before sending.
1404          */
1405         viewer_index.offset = packet_index.offset;
1406         viewer_index.packet_size = packet_index.packet_size;
1407         viewer_index.content_size = packet_index.content_size;
1408         viewer_index.timestamp_begin = packet_index.timestamp_begin;
1409         viewer_index.timestamp_end = packet_index.timestamp_end;
1410         viewer_index.events_discarded = packet_index.events_discarded;
1411         viewer_index.stream_id = packet_index.stream_id;
1412
1413 send_reply:
1414         viewer_index.flags = htobe32(viewer_index.flags);
1415         health_code_update();
1416
1417         ret = send_response(conn->sock, &viewer_index, sizeof(viewer_index));
1418         if (ret < 0) {
1419                 goto end_unlock;
1420         }
1421         health_code_update();
1422
1423         DBG("Index %" PRIu64 " for stream %" PRIu64 " sent",
1424                         vstream->last_sent_index, vstream->stream_handle);
1425
1426 end_unlock:
1427         rcu_read_unlock();
1428
1429 end:
1430         return ret;
1431 }
1432
1433 /*
1434  * Send the next index for a stream
1435  *
1436  * Return 0 on success or else a negative value.
1437  */
1438 static
1439 int viewer_get_packet(struct relay_connection *conn)
1440 {
1441         int ret, send_data = 0;
1442         char *data = NULL;
1443         uint32_t len = 0;
1444         ssize_t read_len;
1445         struct lttng_viewer_get_packet get_packet_info;
1446         struct lttng_viewer_trace_packet reply;
1447         struct relay_viewer_stream *stream;
1448         struct relay_session *session;
1449         struct ctf_trace *ctf_trace;
1450
1451         assert(conn);
1452
1453         DBG2("Relay get data packet");
1454
1455         health_code_update();
1456
1457         ret = recv_request(conn->sock, &get_packet_info, sizeof(get_packet_info));
1458         if (ret < 0) {
1459                 goto end;
1460         }
1461         health_code_update();
1462
1463         /* From this point on, the error label can be reached. */
1464         memset(&reply, 0, sizeof(reply));
1465
1466         rcu_read_lock();
1467         stream = viewer_stream_find_by_id(be64toh(get_packet_info.stream_id));
1468         if (!stream) {
1469                 goto error;
1470         }
1471
1472         session = session_find_by_id(conn->sessions_ht, stream->session_id);
1473         if (!session) {
1474                 ret = -1;
1475                 goto error;
1476         }
1477
1478         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
1479                         stream->path_name);
1480         assert(ctf_trace);
1481
1482         /*
1483          * First time we read this stream, we need open the tracefile, we should
1484          * only arrive here if an index has already been sent to the viewer, so the
1485          * tracefile must exist, if it does not it is a fatal error.
1486          */
1487         if (stream->read_fd < 0) {
1488                 char fullpath[PATH_MAX];
1489
1490                 if (stream->tracefile_count > 0) {
1491                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64, stream->path_name,
1492                                         stream->channel_name,
1493                                         stream->tracefile_count_current);
1494                 } else {
1495                         ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1496                                         stream->channel_name);
1497                 }
1498                 if (ret < 0) {
1499                         goto error;
1500                 }
1501                 ret = open(fullpath, O_RDONLY);
1502                 if (ret < 0) {
1503                         PERROR("Relay opening trace file");
1504                         goto error;
1505                 }
1506                 stream->read_fd = ret;
1507         }
1508
1509         if (!ctf_trace->metadata_received ||
1510                         ctf_trace->metadata_received > ctf_trace->metadata_sent) {
1511                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1512                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1513                 goto send_reply;
1514         }
1515
1516         ret = check_new_streams(conn);
1517         if (ret < 0) {
1518                 goto end_unlock;
1519         } else if (ret == 1) {
1520                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1521                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
1522                 goto send_reply;
1523         }
1524
1525         len = be32toh(get_packet_info.len);
1526         data = zmalloc(len);
1527         if (!data) {
1528                 PERROR("relay data zmalloc");
1529                 goto error;
1530         }
1531
1532         ret = lseek(stream->read_fd, be64toh(get_packet_info.offset), SEEK_SET);
1533         if (ret < 0) {
1534                 /*
1535                  * If the read fd was closed by the streaming side, the
1536                  * abort_flag will be set to 1, otherwise it is an error.
1537                  */
1538                 if (stream->abort_flag == 0) {
1539                         PERROR("lseek");
1540                         goto error;
1541                 }
1542                 reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_EOF);
1543                 goto send_reply;
1544         }
1545         read_len = lttng_read(stream->read_fd, data, len);
1546         if (read_len < len) {
1547                 /*
1548                  * If the read fd was closed by the streaming side, the
1549                  * abort_flag will be set to 1, otherwise it is an error.
1550                  */
1551                 if (stream->abort_flag == 0) {
1552                         PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1553                                         stream->read_fd,
1554                                         be64toh(get_packet_info.offset));
1555                         goto error;
1556                 } else {
1557                         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_EOF);
1558                         goto send_reply;
1559                 }
1560         }
1561         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_OK);
1562         reply.len = htobe32(len);
1563         send_data = 1;
1564         goto send_reply;
1565
1566 error:
1567         reply.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
1568
1569 send_reply:
1570         reply.flags = htobe32(reply.flags);
1571
1572         health_code_update();
1573
1574         ret = send_response(conn->sock, &reply, sizeof(reply));
1575         if (ret < 0) {
1576                 goto end_unlock;
1577         }
1578         health_code_update();
1579
1580         if (send_data) {
1581                 health_code_update();
1582                 ret = send_response(conn->sock, data, len);
1583                 if (ret < 0) {
1584                         goto end_unlock;
1585                 }
1586                 health_code_update();
1587         }
1588
1589         DBG("Sent %u bytes for stream %" PRIu64, len,
1590                         be64toh(get_packet_info.stream_id));
1591
1592 end_unlock:
1593         free(data);
1594         rcu_read_unlock();
1595
1596 end:
1597         return ret;
1598 }
1599
1600 /*
1601  * Send the session's metadata
1602  *
1603  * Return 0 on success else a negative value.
1604  */
1605 static
1606 int viewer_get_metadata(struct relay_connection *conn)
1607 {
1608         int ret = 0;
1609         ssize_t read_len;
1610         uint64_t len = 0;
1611         char *data = NULL;
1612         struct lttng_viewer_get_metadata request;
1613         struct lttng_viewer_metadata_packet reply;
1614         struct relay_viewer_stream *stream;
1615         struct ctf_trace *ctf_trace;
1616         struct relay_session *session;
1617
1618         assert(conn);
1619
1620         DBG("Relay get metadata");
1621
1622         health_code_update();
1623
1624         ret = recv_request(conn->sock, &request, sizeof(request));
1625         if (ret < 0) {
1626                 goto end;
1627         }
1628         health_code_update();
1629
1630         memset(&reply, 0, sizeof(reply));
1631
1632         rcu_read_lock();
1633         stream = viewer_stream_find_by_id(be64toh(request.stream_id));
1634         if (!stream || !stream->metadata_flag) {
1635                 ERR("Invalid metadata stream");
1636                 goto error;
1637         }
1638
1639         session = session_find_by_id(conn->sessions_ht, stream->session_id);
1640         if (!session) {
1641                 ret = -1;
1642                 goto error;
1643         }
1644
1645         ctf_trace = ctf_trace_find_by_path(session->ctf_traces_ht,
1646                         stream->path_name);
1647         assert(ctf_trace);
1648         assert(ctf_trace->metadata_sent <= ctf_trace->metadata_received);
1649
1650         len = ctf_trace->metadata_received - ctf_trace->metadata_sent;
1651         if (len == 0) {
1652                 reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
1653                 goto send_reply;
1654         }
1655
1656         /* first time, we open the metadata file */
1657         if (stream->read_fd < 0) {
1658                 char fullpath[PATH_MAX];
1659
1660                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1661                                 stream->channel_name);
1662                 if (ret < 0) {
1663                         goto error;
1664                 }
1665                 ret = open(fullpath, O_RDONLY);
1666                 if (ret < 0) {
1667                         PERROR("Relay opening metadata file");
1668                         goto error;
1669                 }
1670                 stream->read_fd = ret;
1671         }
1672
1673         reply.len = htobe64(len);
1674         data = zmalloc(len);
1675         if (!data) {
1676                 PERROR("viewer metadata zmalloc");
1677                 goto error;
1678         }
1679
1680         read_len = lttng_read(stream->read_fd, data, len);
1681         if (read_len < len) {
1682                 PERROR("Relay reading metadata file");
1683                 goto error;
1684         }
1685         ctf_trace->metadata_sent += read_len;
1686         reply.status = htobe32(LTTNG_VIEWER_METADATA_OK);
1687         goto send_reply;
1688
1689 error:
1690         reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
1691
1692 send_reply:
1693         health_code_update();
1694         ret = send_response(conn->sock, &reply, sizeof(reply));
1695         if (ret < 0) {
1696                 goto end_unlock;
1697         }
1698         health_code_update();
1699
1700         if (len > 0) {
1701                 ret = send_response(conn->sock, data, len);
1702                 if (ret < 0) {
1703                         goto end_unlock;
1704                 }
1705         }
1706
1707         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1708                         be64toh(request.stream_id));
1709
1710         DBG("Metadata sent");
1711
1712 end_unlock:
1713         free(data);
1714         rcu_read_unlock();
1715 end:
1716         return ret;
1717 }
1718
1719 /*
1720  * Create a viewer session.
1721  *
1722  * Return 0 on success or else a negative value.
1723  */
1724 static
1725 int viewer_create_session(struct relay_connection *conn)
1726 {
1727         int ret;
1728         struct lttng_viewer_create_session_response resp;
1729
1730         DBG("Viewer create session received");
1731
1732         memset(&resp, 0, sizeof(resp));
1733         resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_OK);
1734         conn->viewer_session = zmalloc(sizeof(*conn->viewer_session));
1735         if (!conn->viewer_session) {
1736                 ERR("Allocation viewer session");
1737                 resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_ERR);
1738                 goto send_reply;
1739         }
1740         CDS_INIT_LIST_HEAD(&conn->viewer_session->sessions_head);
1741
1742 send_reply:
1743         health_code_update();
1744         ret = send_response(conn->sock, &resp, sizeof(resp));
1745         if (ret < 0) {
1746                 goto end;
1747         }
1748         health_code_update();
1749         ret = 0;
1750
1751 end:
1752         return ret;
1753 }
1754
1755
1756 /*
1757  * live_relay_unknown_command: send -1 if received unknown command
1758  */
1759 static
1760 void live_relay_unknown_command(struct relay_connection *conn)
1761 {
1762         struct lttcomm_relayd_generic_reply reply;
1763
1764         memset(&reply, 0, sizeof(reply));
1765         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1766         (void) send_response(conn->sock, &reply, sizeof(reply));
1767 }
1768
1769 /*
1770  * Process the commands received on the control socket
1771  */
1772 static
1773 int process_control(struct lttng_viewer_cmd *recv_hdr,
1774                 struct relay_connection *conn)
1775 {
1776         int ret = 0;
1777         uint32_t msg_value;
1778
1779         assert(recv_hdr);
1780         assert(conn);
1781
1782         msg_value = be32toh(recv_hdr->cmd);
1783
1784         /*
1785          * Make sure we've done the version check before any command other then a
1786          * new client connection.
1787          */
1788         if (msg_value != LTTNG_VIEWER_CONNECT && !conn->version_check_done) {
1789                 ERR("Viewer conn value %" PRIu32 " before version check", msg_value);
1790                 ret = -1;
1791                 goto end;
1792         }
1793
1794         switch (msg_value) {
1795         case LTTNG_VIEWER_CONNECT:
1796                 ret = viewer_connect(conn);
1797                 break;
1798         case LTTNG_VIEWER_LIST_SESSIONS:
1799                 ret = viewer_list_sessions(conn);
1800                 break;
1801         case LTTNG_VIEWER_ATTACH_SESSION:
1802                 ret = viewer_attach_session(conn);
1803                 break;
1804         case LTTNG_VIEWER_GET_NEXT_INDEX:
1805                 ret = viewer_get_next_index(conn);
1806                 break;
1807         case LTTNG_VIEWER_GET_PACKET:
1808                 ret = viewer_get_packet(conn);
1809                 break;
1810         case LTTNG_VIEWER_GET_METADATA:
1811                 ret = viewer_get_metadata(conn);
1812                 break;
1813         case LTTNG_VIEWER_GET_NEW_STREAMS:
1814                 ret = viewer_get_new_streams(conn);
1815                 break;
1816         case LTTNG_VIEWER_CREATE_SESSION:
1817                 ret = viewer_create_session(conn);
1818                 break;
1819         default:
1820                 ERR("Received unknown viewer command (%u)", be32toh(recv_hdr->cmd));
1821                 live_relay_unknown_command(conn);
1822                 ret = -1;
1823                 goto end;
1824         }
1825
1826 end:
1827         return ret;
1828 }
1829
1830 static
1831 void cleanup_connection_pollfd(struct lttng_poll_event *events, int pollfd)
1832 {
1833         int ret;
1834
1835         assert(events);
1836
1837         (void) lttng_poll_del(events, pollfd);
1838
1839         ret = close(pollfd);
1840         if (ret < 0) {
1841                 ERR("Closing pollfd %d", pollfd);
1842         }
1843 }
1844
1845 /*
1846  * Delete and destroy a connection.
1847  *
1848  * RCU read side lock MUST be acquired.
1849  */
1850 static void destroy_connection(struct lttng_ht *relay_connections_ht,
1851                 struct relay_connection *conn)
1852 {
1853         struct relay_session *session, *tmp_session;
1854
1855         assert(relay_connections_ht);
1856         assert(conn);
1857
1858         connection_delete(relay_connections_ht, conn);
1859
1860         if (!conn->viewer_session) {
1861                 goto end;
1862         }
1863
1864         rcu_read_lock();
1865         cds_list_for_each_entry_safe(session, tmp_session,
1866                         &conn->viewer_session->sessions_head,
1867                         viewer_session_list) {
1868                 DBG("Cleaning connection of session ID %" PRIu64, session->id);
1869                 cleanup_session(conn, session);
1870         }
1871         rcu_read_unlock();
1872
1873 end:
1874         connection_destroy(conn);
1875 }
1876
1877 /*
1878  * This thread does the actual work
1879  */
1880 static
1881 void *thread_worker(void *data)
1882 {
1883         int ret, err = -1;
1884         uint32_t nb_fd;
1885         struct relay_connection *conn;
1886         struct lttng_poll_event events;
1887         struct lttng_ht *relay_connections_ht;
1888         struct lttng_ht_iter iter;
1889         struct lttng_viewer_cmd recv_hdr;
1890         struct relay_local_data *relay_ctx = (struct relay_local_data *) data;
1891         struct lttng_ht *sessions_ht = relay_ctx->sessions_ht;
1892
1893         DBG("[thread] Live viewer relay worker started");
1894
1895         rcu_register_thread();
1896
1897         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1898
1899         if (testpoint(relayd_thread_live_worker)) {
1900                 goto error_testpoint;
1901         }
1902
1903         /* table of connections indexed on socket */
1904         relay_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1905         if (!relay_connections_ht) {
1906                 goto relay_connections_ht_error;
1907         }
1908
1909         ret = create_thread_poll_set(&events, 2);
1910         if (ret < 0) {
1911                 goto error_poll_create;
1912         }
1913
1914         ret = lttng_poll_add(&events, live_conn_pipe[0], LPOLLIN | LPOLLRDHUP);
1915         if (ret < 0) {
1916                 goto error;
1917         }
1918
1919 restart:
1920         while (1) {
1921                 int i;
1922
1923                 health_code_update();
1924
1925                 /* Infinite blocking call, waiting for transmission */
1926                 DBG3("Relayd live viewer worker thread polling...");
1927                 health_poll_entry();
1928                 ret = lttng_poll_wait(&events, -1);
1929                 health_poll_exit();
1930                 if (ret < 0) {
1931                         /*
1932                          * Restart interrupted system call.
1933                          */
1934                         if (errno == EINTR) {
1935                                 goto restart;
1936                         }
1937                         goto error;
1938                 }
1939
1940                 nb_fd = ret;
1941
1942                 /*
1943                  * Process control. The control connection is prioritised so we don't
1944                  * starve it with high throughput tracing data on the data
1945                  * connection.
1946                  */
1947                 for (i = 0; i < nb_fd; i++) {
1948                         /* Fetch once the poll data */
1949                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1950                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1951
1952                         health_code_update();
1953
1954                         /* Thread quit pipe has been closed. Killing thread. */
1955                         ret = check_thread_quit_pipe(pollfd, revents);
1956                         if (ret) {
1957                                 err = 0;
1958                                 goto exit;
1959                         }
1960
1961                         /* Inspect the relay conn pipe for new connection */
1962                         if (pollfd == live_conn_pipe[0]) {
1963                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1964                                         ERR("Relay live pipe error");
1965                                         goto error;
1966                                 } else if (revents & LPOLLIN) {
1967                                         ret = lttng_read(live_conn_pipe[0], &conn, sizeof(conn));
1968                                         if (ret < 0) {
1969                                                 goto error;
1970                                         }
1971                                         conn->sessions_ht = sessions_ht;
1972                                         connection_init(conn);
1973                                         lttng_poll_add(&events, conn->sock->fd,
1974                                                         LPOLLIN | LPOLLRDHUP);
1975                                         rcu_read_lock();
1976                                         lttng_ht_add_unique_ulong(relay_connections_ht,
1977                                                         &conn->sock_n);
1978                                         rcu_read_unlock();
1979                                         DBG("Connection socket %d added", conn->sock->fd);
1980                                 }
1981                         } else {
1982                                 rcu_read_lock();
1983                                 conn = connection_find_by_sock(relay_connections_ht, pollfd);
1984                                 /* If not found, there is a synchronization issue. */
1985                                 assert(conn);
1986
1987                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1988                                         cleanup_connection_pollfd(&events, pollfd);
1989                                         destroy_connection(relay_connections_ht, conn);
1990                                 } else if (revents & LPOLLIN) {
1991                                         ret = conn->sock->ops->recvmsg(conn->sock, &recv_hdr,
1992                                                         sizeof(recv_hdr), 0);
1993                                         if (ret <= 0) {
1994                                                 /* Connection closed */
1995                                                 cleanup_connection_pollfd(&events, pollfd);
1996                                                 destroy_connection(relay_connections_ht, conn);
1997                                                 DBG("Viewer control conn closed with %d", pollfd);
1998                                         } else {
1999                                                 ret = process_control(&recv_hdr, conn);
2000                                                 if (ret < 0) {
2001                                                         /* Clear the session on error. */
2002                                                         cleanup_connection_pollfd(&events, pollfd);
2003                                                         destroy_connection(relay_connections_ht, conn);
2004                                                         DBG("Viewer connection closed with %d", pollfd);
2005                                                 }
2006                                         }
2007                                 }
2008                                 rcu_read_unlock();
2009                         }
2010                 }
2011         }
2012
2013 exit:
2014 error:
2015         lttng_poll_clean(&events);
2016
2017         /* Cleanup reamaining connection object. */
2018         rcu_read_lock();
2019         cds_lfht_for_each_entry(relay_connections_ht->ht, &iter.iter, conn,
2020                         sock_n.node) {
2021                 health_code_update();
2022                 destroy_connection(relay_connections_ht, conn);
2023         }
2024         rcu_read_unlock();
2025 error_poll_create:
2026         lttng_ht_destroy(relay_connections_ht);
2027 relay_connections_ht_error:
2028         /* Close relay conn pipes */
2029         utils_close_pipe(live_conn_pipe);
2030         if (err) {
2031                 DBG("Viewer worker thread exited with error");
2032         }
2033         DBG("Viewer worker thread cleanup complete");
2034 error_testpoint:
2035         if (err) {
2036                 health_error();
2037                 ERR("Health error occurred in %s", __func__);
2038         }
2039         health_unregister(health_relayd);
2040         stop_threads();
2041         rcu_unregister_thread();
2042         return NULL;
2043 }
2044
2045 /*
2046  * Create the relay command pipe to wake thread_manage_apps.
2047  * Closed in cleanup().
2048  */
2049 static int create_conn_pipe(void)
2050 {
2051         int ret;
2052
2053         ret = utils_create_pipe_cloexec(live_conn_pipe);
2054
2055         return ret;
2056 }
2057
2058 void live_stop_threads(void)
2059 {
2060         int ret;
2061         void *status;
2062
2063         stop_threads();
2064
2065         ret = pthread_join(live_listener_thread, &status);
2066         if (ret != 0) {
2067                 PERROR("pthread_join live listener");
2068                 goto error;     /* join error, exit without cleanup */
2069         }
2070
2071         ret = pthread_join(live_worker_thread, &status);
2072         if (ret != 0) {
2073                 PERROR("pthread_join live worker");
2074                 goto error;     /* join error, exit without cleanup */
2075         }
2076
2077         ret = pthread_join(live_dispatcher_thread, &status);
2078         if (ret != 0) {
2079                 PERROR("pthread_join live dispatcher");
2080                 goto error;     /* join error, exit without cleanup */
2081         }
2082
2083         cleanup();
2084
2085 error:
2086         return;
2087 }
2088
2089 /*
2090  * main
2091  */
2092 int live_start_threads(struct lttng_uri *uri,
2093                 struct relay_local_data *relay_ctx)
2094 {
2095         int ret = 0;
2096         void *status;
2097         int is_root;
2098
2099         assert(uri);
2100         live_uri = uri;
2101
2102         /* Check if daemon is UID = 0 */
2103         is_root = !getuid();
2104
2105         if (!is_root) {
2106                 if (live_uri->port < 1024) {
2107                         ERR("Need to be root to use ports < 1024");
2108                         ret = -1;
2109                         goto exit;
2110                 }
2111         }
2112
2113         /* Setup the thread apps communication pipe. */
2114         if ((ret = create_conn_pipe()) < 0) {
2115                 goto exit;
2116         }
2117
2118         /* Init relay command queue. */
2119         cds_wfcq_init(&viewer_conn_queue.head, &viewer_conn_queue.tail);
2120
2121         /* Set up max poll set size */
2122         lttng_poll_set_max_size();
2123
2124         /* Setup the dispatcher thread */
2125         ret = pthread_create(&live_dispatcher_thread, NULL,
2126                         thread_dispatcher, (void *) NULL);
2127         if (ret != 0) {
2128                 PERROR("pthread_create viewer dispatcher");
2129                 goto exit_dispatcher;
2130         }
2131
2132         /* Setup the worker thread */
2133         ret = pthread_create(&live_worker_thread, NULL,
2134                         thread_worker, relay_ctx);
2135         if (ret != 0) {
2136                 PERROR("pthread_create viewer worker");
2137                 goto exit_worker;
2138         }
2139
2140         /* Setup the listener thread */
2141         ret = pthread_create(&live_listener_thread, NULL,
2142                         thread_listener, (void *) NULL);
2143         if (ret != 0) {
2144                 PERROR("pthread_create viewer listener");
2145                 goto exit_listener;
2146         }
2147
2148         ret = 0;
2149         goto end;
2150
2151 exit_listener:
2152         ret = pthread_join(live_listener_thread, &status);
2153         if (ret != 0) {
2154                 PERROR("pthread_join live listener");
2155                 goto error;     /* join error, exit without cleanup */
2156         }
2157
2158 exit_worker:
2159         ret = pthread_join(live_worker_thread, &status);
2160         if (ret != 0) {
2161                 PERROR("pthread_join live worker");
2162                 goto error;     /* join error, exit without cleanup */
2163         }
2164
2165 exit_dispatcher:
2166         ret = pthread_join(live_dispatcher_thread, &status);
2167         if (ret != 0) {
2168                 PERROR("pthread_join live dispatcher");
2169                 goto error;     /* join error, exit without cleanup */
2170         }
2171
2172 exit:
2173         cleanup();
2174
2175 end:
2176 error:
2177         return ret;
2178 }