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