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/sessiond-comm/sessiond-comm.h>
  49 #include <common/sessiond-comm/inet.h>
  50 #include <common/sessiond-comm/relayd.h>
  51 #include <common/uri.h>
  52 #include <common/utils.h>
  53
  54 #include "cmd.h"
  55 #include "live.h"
  56 #include "lttng-relayd.h"
  57 #include "lttng-viewer.h"
  58 #include "utils.h"
  59 #include "health-relayd.h"
  60
  61 static struct lttng_uri *live_uri;
  62
  63 /*
  64  * This pipe is used to inform the worker thread that a command is queued and
  65  * ready to be processed.
  66  */
  67 static int live_relay_cmd_pipe[2] = { -1, -1 };
  68
  69 /* Shared between threads */
  70 static int live_dispatch_thread_exit;
  71
  72 static pthread_t live_listener_thread;
  73 static pthread_t live_dispatcher_thread;
  74 static pthread_t live_worker_thread;
  75
  76 /*
  77  * Relay command queue.
  78  *
  79  * The live_thread_listener and live_thread_dispatcher communicate with this
  80  * queue.
  81  */
  82 static struct relay_cmd_queue viewer_cmd_queue;
  83
  84 static uint64_t last_relay_viewer_session_id;
  85
  86 /*
  87  * Cleanup the daemon
  88  */
  89 static
  90 void cleanup(void)
  91 {
  92         DBG("Cleaning up");
  93
  94         free(live_uri);
  95 }
  96
  97 /*
  98  * Write to writable pipe used to notify a thread.
  99  */
 100 static
 101 int notify_thread_pipe(int wpipe)
 102 {
 103         ssize_t ret;
 104
 105         ret = lttng_write(wpipe, "!", 1);
 106         if (ret < 1) {
 107                 PERROR("write poll pipe");
 108         }
 109
 110         return (int) ret;
 111 }
 112
 113 /*
 114  * Stop all threads by closing the thread quit pipe.
 115  */
 116 static
 117 void stop_threads(void)
 118 {
 119         int ret;
 120
 121         /* Stopping all threads */
 122         DBG("Terminating all live threads");
 123         ret = notify_thread_pipe(thread_quit_pipe[1]);
 124         if (ret < 0) {
 125                 ERR("write error on thread quit pipe");
 126         }
 127
 128         /* Dispatch thread */
 129         CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
 130         futex_nto1_wake(&viewer_cmd_queue.futex);
 131 }
 132
 133 /*
 134  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 135  */
 136 static
 137 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 138 {
 139         int ret;
 140
 141         if (events == NULL || size == 0) {
 142                 ret = -1;
 143                 goto error;
 144         }
 145
 146         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 147         if (ret < 0) {
 148                 goto error;
 149         }
 150
 151         /* Add quit pipe */
 152         ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
 153         if (ret < 0) {
 154                 goto error;
 155         }
 156
 157         return 0;
 158
 159 error:
 160         return ret;
 161 }
 162
 163 /*
 164  * Check if the thread quit pipe was triggered.
 165  *
 166  * Return 1 if it was triggered else 0;
 167  */
 168 static
 169 int check_thread_quit_pipe(int fd, uint32_t events)
 170 {
 171         if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
 172                 return 1;
 173         }
 174
 175         return 0;
 176 }
 177
 178 /*
 179  * Create and init socket from uri.
 180  */
 181 static
 182 struct lttcomm_sock *init_socket(struct lttng_uri *uri)
 183 {
 184         int ret;
 185         struct lttcomm_sock *sock = NULL;
 186
 187         sock = lttcomm_alloc_sock_from_uri(uri);
 188         if (sock == NULL) {
 189                 ERR("Allocating socket");
 190                 goto error;
 191         }
 192
 193         ret = lttcomm_create_sock(sock);
 194         if (ret < 0) {
 195                 goto error;
 196         }
 197         DBG("Listening on sock %d for live", sock->fd);
 198
 199         ret = sock->ops->bind(sock);
 200         if (ret < 0) {
 201                 goto error;
 202         }
 203
 204         ret = sock->ops->listen(sock, -1);
 205         if (ret < 0) {
 206                 goto error;
 207
 208         }
 209
 210         return sock;
 211
 212 error:
 213         if (sock) {
 214                 lttcomm_destroy_sock(sock);
 215         }
 216         return NULL;
 217 }
 218
 219 /*
 220  * This thread manages the listening for new connections on the network
 221  */
 222 static
 223 void *thread_listener(void *data)
 224 {
 225         int i, ret, pollfd, err = -1;
 226         int val = 1;
 227         uint32_t revents, nb_fd;
 228         struct lttng_poll_event events;
 229         struct lttcomm_sock *live_control_sock;
 230
 231         DBG("[thread] Relay live listener started");
 232
 233         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_LISTENER);
 234
 235         health_code_update();
 236
 237         live_control_sock = init_socket(live_uri);
 238         if (!live_control_sock) {
 239                 goto error_sock_control;
 240         }
 241
 242         /* Pass 2 as size here for the thread quit pipe and control sockets. */
 243         ret = create_thread_poll_set(&events, 2);
 244         if (ret < 0) {
 245                 goto error_create_poll;
 246         }
 247
 248         /* Add the control socket */
 249         ret = lttng_poll_add(&events, live_control_sock->fd, LPOLLIN | LPOLLRDHUP);
 250         if (ret < 0) {
 251                 goto error_poll_add;
 252         }
 253
 254         lttng_relay_notify_ready();
 255
 256         while (1) {
 257                 health_code_update();
 258
 259                 DBG("Listener accepting live viewers connections");
 260
 261 restart:
 262                 health_poll_entry();
 263                 ret = lttng_poll_wait(&events, -1);
 264                 health_poll_exit();
 265                 if (ret < 0) {
 266                         /*
 267                          * Restart interrupted system call.
 268                          */
 269                         if (errno == EINTR) {
 270                                 goto restart;
 271                         }
 272                         goto error;
 273                 }
 274                 nb_fd = ret;
 275
 276                 DBG("Relay new viewer connection received");
 277                 for (i = 0; i < nb_fd; i++) {
 278                         health_code_update();
 279
 280                         /* Fetch once the poll data */
 281                         revents = LTTNG_POLL_GETEV(&events, i);
 282                         pollfd = LTTNG_POLL_GETFD(&events, i);
 283
 284                         /* Thread quit pipe has been closed. Killing thread. */
 285                         ret = check_thread_quit_pipe(pollfd, revents);
 286                         if (ret) {
 287                                 err = 0;
 288                                 goto exit;
 289                         }
 290
 291                         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 292                                 ERR("socket poll error");
 293                                 goto error;
 294                         } else if (revents & LPOLLIN) {
 295                                 /*
 296                                  * Get allocated in this thread, enqueued to a global queue,
 297                                  * dequeued and freed in the worker thread.
 298                                  */
 299                                 struct relay_command *relay_cmd;
 300                                 struct lttcomm_sock *newsock;
 301
 302                                 relay_cmd = zmalloc(sizeof(*relay_cmd));
 303                                 if (!relay_cmd) {
 304                                         PERROR("relay command zmalloc");
 305                                         goto error;
 306                                 }
 307
 308                                 assert(pollfd == live_control_sock->fd);
 309                                 newsock = live_control_sock->ops->accept(live_control_sock);
 310                                 if (!newsock) {
 311                                         PERROR("accepting control sock");
 312                                         free(relay_cmd);
 313                                         goto error;
 314                                 }
 315                                 DBG("Relay viewer connection accepted socket %d", newsock->fd);
 316                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR, &val,
 317                                                 sizeof(int));
 318                                 if (ret < 0) {
 319                                         PERROR("setsockopt inet");
 320                                         lttcomm_destroy_sock(newsock);
 321                                         free(relay_cmd);
 322                                         goto error;
 323                                 }
 324                                 relay_cmd->sock = newsock;
 325
 326                                 /*
 327                                  * Lock free enqueue the request.
 328                                  */
 329                                 cds_wfq_enqueue(&viewer_cmd_queue.queue, &relay_cmd->node);
 330
 331                                 /*
 332                                  * Wake the dispatch queue futex. Implicit memory
 333                                  * barrier with the exchange in cds_wfq_enqueue.
 334                                  */
 335                                 futex_nto1_wake(&viewer_cmd_queue.futex);
 336                         }
 337                 }
 338         }
 339
 340 exit:
 341 error:
 342 error_poll_add:
 343         lttng_poll_clean(&events);
 344 error_create_poll:
 345         if (live_control_sock->fd >= 0) {
 346                 ret = live_control_sock->ops->close(live_control_sock);
 347                 if (ret) {
 348                         PERROR("close");
 349                 }
 350         }
 351         lttcomm_destroy_sock(live_control_sock);
 352 error_sock_control:
 353         if (err) {
 354                 health_error();
 355                 DBG("Live viewer listener thread exited with error");
 356         }
 357         health_unregister(health_relayd);
 358         DBG("Live viewer listener thread cleanup complete");
 359         stop_threads();
 360         return NULL;
 361 }
 362
 363 /*
 364  * This thread manages the dispatching of the requests to worker threads
 365  */
 366 static
 367 void *thread_dispatcher(void *data)
 368 {
 369         int err = -1;
 370         ssize_t ret;
 371         struct cds_wfq_node *node;
 372         struct relay_command *relay_cmd = NULL;
 373
 374         DBG("[thread] Live viewer relay dispatcher started");
 375
 376         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 377
 378         health_code_update();
 379
 380         while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
 381                 health_code_update();
 382
 383                 /* Atomically prepare the queue futex */
 384                 futex_nto1_prepare(&viewer_cmd_queue.futex);
 385
 386                 do {
 387                         health_code_update();
 388
 389                         /* Dequeue commands */
 390                         node = cds_wfq_dequeue_blocking(&viewer_cmd_queue.queue);
 391                         if (node == NULL) {
 392                                 DBG("Woken up but nothing in the live-viewer "
 393                                                 "relay command queue");
 394                                 /* Continue thread execution */
 395                                 break;
 396                         }
 397
 398                         relay_cmd = caa_container_of(node, struct relay_command, node);
 399                         DBG("Dispatching viewer request waiting on sock %d",
 400                                         relay_cmd->sock->fd);
 401
 402                         /*
 403                          * Inform worker thread of the new request. This call is blocking
 404                          * so we can be assured that the data will be read at some point in
 405                          * time or wait to the end of the world :)
 406                          */
 407                         ret = lttng_write(live_relay_cmd_pipe[1], relay_cmd,
 408                                         sizeof(*relay_cmd));
 409                         free(relay_cmd);
 410                         if (ret < sizeof(struct relay_command)) {
 411                                 PERROR("write cmd pipe");
 412                                 goto error;
 413                         }
 414                 } while (node != NULL);
 415
 416                 /* Futex wait on queue. Blocking call on futex() */
 417                 health_poll_entry();
 418                 futex_nto1_wait(&viewer_cmd_queue.futex);
 419                 health_poll_exit();
 420         }
 421
 422         /* Normal exit, no error */
 423         err = 0;
 424
 425 error:
 426         if (err) {
 427                 health_error();
 428                 ERR("Health error occurred in %s", __func__);
 429         }
 430         health_unregister(health_relayd);
 431         DBG("Live viewer dispatch thread dying");
 432         stop_threads();
 433         return NULL;
 434 }
 435
 436 /*
 437  * Establish connection with the viewer and check the versions.
 438  *
 439  * Return 0 on success or else negative value.
 440  */
 441 static
 442 int viewer_connect(struct relay_command *cmd)
 443 {
 444         int ret;
 445         struct lttng_viewer_connect reply, msg;
 446
 447         assert(cmd);
 448
 449         cmd->version_check_done = 1;
 450
 451         health_code_update();
 452
 453         /* Get version from the other side. */
 454         ret = cmd->sock->ops->recvmsg(cmd->sock, &msg, sizeof(msg), 0);
 455         if (ret < 0 || ret != sizeof(msg)) {
 456                 if (ret == 0) {
 457                         /* Orderly shutdown. Not necessary to print an error. */
 458                         DBG("Socket %d did an orderly shutdown", cmd->sock->fd);
 459                 } else {
 460                         ERR("Relay failed to receive the version values.");
 461                 }
 462                 ret = -1;
 463                 goto end;
 464         }
 465
 466         health_code_update();
 467
 468         reply.major = RELAYD_VERSION_COMM_MAJOR;
 469         reply.minor = RELAYD_VERSION_COMM_MINOR;
 470
 471         /* Major versions must be the same */
 472         if (reply.major != be32toh(msg.major)) {
 473                 DBG("Incompatible major versions (%u vs %u)", reply.major,
 474                                 be32toh(msg.major));
 475                 ret = -1;
 476                 goto end;
 477         }
 478
 479         cmd->major = reply.major;
 480         /* We adapt to the lowest compatible version */
 481         if (reply.minor <= be32toh(msg.minor)) {
 482                 cmd->minor = reply.minor;
 483         } else {
 484                 cmd->minor = be32toh(msg.minor);
 485         }
 486
 487         if (be32toh(msg.type) == VIEWER_CLIENT_COMMAND) {
 488                 cmd->type = RELAY_VIEWER_COMMAND;
 489         } else if (be32toh(msg.type) == VIEWER_CLIENT_NOTIFICATION) {
 490                 cmd->type = RELAY_VIEWER_NOTIFICATION;
 491         } else {
 492                 ERR("Unknown connection type : %u", be32toh(msg.type));
 493                 ret = -1;
 494                 goto end;
 495         }
 496
 497         reply.major = htobe32(reply.major);
 498         reply.minor = htobe32(reply.minor);
 499         if (cmd->type == RELAY_VIEWER_COMMAND) {
 500                 reply.viewer_session_id = htobe64(++last_relay_viewer_session_id);
 501         }
 502
 503         health_code_update();
 504
 505         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
 506                         sizeof(struct lttng_viewer_connect), 0);
 507         if (ret < 0) {
 508                 ERR("Relay sending version");
 509         }
 510
 511         health_code_update();
 512
 513         DBG("Version check done using protocol %u.%u", cmd->major, cmd->minor);
 514         ret = 0;
 515
 516 end:
 517         return ret;
 518 }
 519
 520 /*
 521  * Send the viewer the list of current sessions.
 522  *
 523  * Return 0 on success or else a negative value.
 524  */
 525 static
 526 int viewer_list_sessions(struct relay_command *cmd,
 527                 struct lttng_ht *sessions_ht)
 528 {
 529         int ret;
 530         struct lttng_viewer_list_sessions session_list;
 531         unsigned long count;
 532         long approx_before, approx_after;
 533         struct lttng_ht_node_ulong *node;
 534         struct lttng_ht_iter iter;
 535         struct lttng_viewer_session send_session;
 536         struct relay_session *session;
 537
 538         DBG("List sessions received");
 539
 540         if (cmd->version_check_done == 0) {
 541                 ERR("Trying to list sessions before version check");
 542                 ret = -1;
 543                 goto end_no_session;
 544         }
 545
 546         rcu_read_lock();
 547         cds_lfht_count_nodes(sessions_ht->ht, &approx_before, &count, &approx_after);
 548         session_list.sessions_count = htobe32(count);
 549
 550         health_code_update();
 551
 552         ret = cmd->sock->ops->sendmsg(cmd->sock, &session_list,
 553                         sizeof(session_list), 0);
 554         if (ret < 0) {
 555                 ERR("Relay sending sessions list");
 556                 goto end_unlock;
 557         }
 558
 559         health_code_update();
 560
 561         cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, node, node) {
 562                 health_code_update();
 563
 564                 node = lttng_ht_iter_get_node_ulong(&iter);
 565                 if (!node) {
 566                         goto end_unlock;
 567                 }
 568                 session = caa_container_of(node, struct relay_session, session_n);
 569
 570                 strncpy(send_session.session_name, session->session_name,
 571                                 sizeof(send_session.session_name));
 572                 strncpy(send_session.hostname, session->hostname,
 573                                 sizeof(send_session.hostname));
 574                 send_session.id = htobe64(session->id);
 575                 send_session.live_timer = htobe32(session->live_timer);
 576                 send_session.clients = htobe32(session->viewer_attached);
 577                 send_session.streams = htobe32(session->stream_count);
 578
 579                 health_code_update();
 580
 581                 ret = cmd->sock->ops->sendmsg(cmd->sock, &send_session,
 582                                 sizeof(send_session), 0);
 583                 if (ret < 0) {
 584                         ERR("Relay sending session info");
 585                         goto end_unlock;
 586                 }
 587         }
 588         health_code_update();
 589
 590         rcu_read_unlock();
 591         ret = 0;
 592         goto end;
 593
 594 end_unlock:
 595         rcu_read_unlock();
 596
 597 end:
 598 end_no_session:
 599         return ret;
 600 }
 601
 602 /*
 603  * Open index file using a given viewer stream.
 604  *
 605  * Return 0 on success or else a negative value.
 606  */
 607 static int open_index(struct relay_viewer_stream *stream)
 608 {
 609         int ret;
 610         char fullpath[PATH_MAX];
 611         struct ctf_packet_index_file_hdr hdr;
 612
 613         if (stream->tracefile_count > 0) {
 614                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 615                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, stream->path_name,
 616                                 stream->channel_name, stream->tracefile_count_current);
 617         } else {
 618                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 619                                 DEFAULT_INDEX_FILE_SUFFIX, stream->path_name,
 620                                 stream->channel_name);
 621         }
 622         if (ret < 0) {
 623                 PERROR("snprintf index path");
 624                 goto error;
 625         }
 626
 627         DBG("Opening index file %s in read only", fullpath);
 628         ret = open(fullpath, O_RDONLY);
 629         if (ret < 0) {
 630                 if (errno == ENOENT) {
 631                         ret = -ENOENT;
 632                         goto error;
 633                 } else {
 634                         PERROR("opening index in read-only");
 635                 }
 636                 goto error;
 637         }
 638         stream->index_read_fd = ret;
 639         DBG("Opening index file %s in read only, (fd: %d)", fullpath, ret);
 640
 641         ret = lttng_read(stream->index_read_fd, &hdr, sizeof(hdr));
 642         if (ret < sizeof(hdr)) {
 643                 PERROR("Reading index header");
 644                 goto error;
 645         }
 646         if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 647                 ERR("Invalid header magic");
 648                 ret = -1;
 649                 goto error;
 650         }
 651         if (be32toh(hdr.index_major) != CTF_INDEX_MAJOR ||
 652                         be32toh(hdr.index_minor) != CTF_INDEX_MINOR) {
 653                 ERR("Invalid header version");
 654                 ret = -1;
 655                 goto error;
 656         }
 657         ret = 0;
 658
 659 error:
 660         return ret;
 661 }
 662
 663 /*
 664  * Allocate and init a new viewer_stream.
 665  *
 666  * Copies the values from the stream passed in parameter and insert the new
 667  * stream in the viewer_streams_ht.
 668  *
 669  * MUST be called with rcu_read_lock held.
 670  *
 671  * Returns 0 on success or a negative value on error.
 672  */
 673 static
 674 int init_viewer_stream(struct relay_stream *stream, int seek_last)
 675 {
 676         int ret;
 677         struct relay_viewer_stream *viewer_stream;
 678
 679         assert(stream);
 680
 681         viewer_stream = zmalloc(sizeof(*viewer_stream));
 682         if (!viewer_stream) {
 683                 PERROR("relay viewer stream zmalloc");
 684                 ret = -1;
 685                 goto error;
 686         }
 687         viewer_stream->session_id = stream->session->id;
 688         viewer_stream->stream_handle = stream->stream_handle;
 689         viewer_stream->path_name = strndup(stream->path_name,
 690                         LTTNG_VIEWER_PATH_MAX);
 691         viewer_stream->channel_name = strndup(stream->channel_name,
 692                         LTTNG_VIEWER_NAME_MAX);
 693         viewer_stream->tracefile_count = stream->tracefile_count;
 694         viewer_stream->metadata_flag = stream->metadata_flag;
 695         viewer_stream->tracefile_count_last = -1ULL;
 696         if (seek_last) {
 697                 viewer_stream->tracefile_count_current =
 698                         stream->tracefile_count_current;
 699         } else {
 700                 viewer_stream->tracefile_count_current =
 701                         stream->oldest_tracefile_id;
 702         }
 703
 704         viewer_stream->ctf_trace = stream->ctf_trace;
 705         if (viewer_stream->metadata_flag) {
 706                 viewer_stream->ctf_trace->viewer_metadata_stream =
 707                         viewer_stream;
 708         }
 709         uatomic_inc(&viewer_stream->ctf_trace->refcount);
 710
 711         lttng_ht_node_init_u64(&viewer_stream->stream_n, stream->stream_handle);
 712         lttng_ht_add_unique_u64(viewer_streams_ht, &viewer_stream->stream_n);
 713
 714         viewer_stream->index_read_fd = -1;
 715         viewer_stream->read_fd = -1;
 716
 717         /*
 718          * This is to avoid a race between the initialization of this object and
 719          * the close of the given stream. If the stream is unable to find this
 720          * viewer stream when closing, this copy will at least take the latest
 721          * value.
 722          * We also need that for the seek_last.
 723          */
 724         viewer_stream->total_index_received = stream->total_index_received;
 725
 726         /*
 727          * If we never received an index for the current stream, delay
 728          * the opening of the index, otherwise open it right now.
 729          */
 730         if (viewer_stream->tracefile_count_current ==
 731                         stream->tracefile_count_current &&
 732                         viewer_stream->total_index_received == 0) {
 733                 viewer_stream->index_read_fd = -1;
 734         } else {
 735                 ret = open_index(viewer_stream);
 736                 if (ret < 0) {
 737                         goto error;
 738                 }
 739         }
 740
 741         if (seek_last && viewer_stream->index_read_fd > 0) {
 742                 ret = lseek(viewer_stream->index_read_fd,
 743                                 viewer_stream->total_index_received *
 744                                         sizeof(struct ctf_packet_index),
 745                                 SEEK_CUR);
 746                 if (ret < 0) {
 747                         goto error;
 748                 }
 749                 viewer_stream->last_sent_index =
 750                         viewer_stream->total_index_received;
 751         }
 752
 753         ret = 0;
 754
 755 error:
 756         return ret;
 757 }
 758
 759 /*
 760  * Rotate a stream to the next tracefile.
 761  *
 762  * Returns 0 on success, 1 on EOF, a negative value on error.
 763  */
 764 static
 765 int rotate_viewer_stream(struct relay_viewer_stream *viewer_stream,
 766                 struct relay_stream *stream)
 767 {
 768         int ret;
 769         uint64_t tracefile_id;
 770
 771         assert(viewer_stream);
 772
 773         tracefile_id = (viewer_stream->tracefile_count_current + 1) %
 774                 viewer_stream->tracefile_count;
 775         /*
 776          * Detect the last tracefile to open.
 777          */
 778         if (viewer_stream->tracefile_count_last != -1ULL &&
 779                         viewer_stream->tracefile_count_last ==
 780                         viewer_stream->tracefile_count_current) {
 781                 ret = 1;
 782                 goto end;
 783         }
 784
 785         if (stream) {
 786                 pthread_mutex_lock(&stream->viewer_stream_rotation_lock);
 787         }
 788         /*
 789          * The writer and the reader are not working in the same
 790          * tracefile, we can read up to EOF, we don't care about the
 791          * total_index_received.
 792          */
 793         if (!stream || (stream->tracefile_count_current != tracefile_id)) {
 794                 viewer_stream->close_write_flag = 1;
 795         } else {
 796                 /*
 797                  * We are opening a file that is still open in write, make
 798                  * sure we limit our reading to the number of indexes
 799                  * received.
 800                  */
 801                 viewer_stream->close_write_flag = 0;
 802                 if (stream) {
 803                         viewer_stream->total_index_received =
 804                                 stream->total_index_received;
 805                 }
 806         }
 807         viewer_stream->tracefile_count_current = tracefile_id;
 808
 809         ret = close(viewer_stream->index_read_fd);
 810         if (ret < 0) {
 811                 PERROR("close index file %d",
 812                                 viewer_stream->index_read_fd);
 813         }
 814         viewer_stream->index_read_fd = -1;
 815         ret = close(viewer_stream->read_fd);
 816         if (ret < 0) {
 817                 PERROR("close tracefile %d",
 818                                 viewer_stream->read_fd);
 819         }
 820         viewer_stream->read_fd = -1;
 821
 822         pthread_mutex_lock(&viewer_stream->overwrite_lock);
 823         viewer_stream->abort_flag = 0;
 824         pthread_mutex_unlock(&viewer_stream->overwrite_lock);
 825
 826         viewer_stream->index_read_fd = -1;
 827         viewer_stream->read_fd = -1;
 828
 829         if (stream) {
 830                 pthread_mutex_unlock(&stream->viewer_stream_rotation_lock);
 831         }
 832         ret = open_index(viewer_stream);
 833         if (ret < 0) {
 834                 goto error;
 835         }
 836
 837         ret = 0;
 838
 839 end:
 840 error:
 841         return ret;
 842 }
 843
 844 /*
 845  * Send the viewer the list of current sessions.
 846  */
 847 static
 848 int viewer_attach_session(struct relay_command *cmd,
 849                 struct lttng_ht *sessions_ht)
 850 {
 851         int ret, send_streams = 0;
 852         uint32_t nb_streams = 0, nb_streams_ready = 0;
 853         struct lttng_viewer_attach_session_request request;
 854         struct lttng_viewer_attach_session_response response;
 855         struct lttng_viewer_stream send_stream;
 856         struct relay_stream *stream;
 857         struct relay_viewer_stream *viewer_stream;
 858         struct lttng_ht_node_ulong *node;
 859         struct lttng_ht_node_u64 *node64;
 860         struct lttng_ht_iter iter;
 861         struct relay_session *session;
 862         int seek_last = 0;
 863
 864         assert(cmd);
 865         assert(sessions_ht);
 866
 867         DBG("Attach session received");
 868
 869         if (cmd->version_check_done == 0) {
 870                 ERR("Trying to attach session before version check");
 871                 ret = -1;
 872                 goto end_no_session;
 873         }
 874
 875         health_code_update();
 876
 877         ret = cmd->sock->ops->recvmsg(cmd->sock, &request, sizeof(request), 0);
 878         if (ret < 0 || ret != sizeof(request)) {
 879                 if (ret == 0) {
 880                         /* Orderly shutdown. Not necessary to print an error. */
 881                         DBG("Socket %d did an orderly shutdown", cmd->sock->fd);
 882                 } else {
 883                         ERR("Relay failed to receive the attach parameters.");
 884                 }
 885                 ret = -1;
 886                 goto error;
 887         }
 888
 889         health_code_update();
 890
 891         rcu_read_lock();
 892         lttng_ht_lookup(sessions_ht,
 893                         (void *)((unsigned long) be64toh(request.session_id)), &iter);
 894         node = lttng_ht_iter_get_node_ulong(&iter);
 895         if (node == NULL) {
 896                 DBG("Relay session %" PRIu64 " not found",
 897                                 be64toh(request.session_id));
 898                 response.status = htobe32(VIEWER_ATTACH_UNK);
 899                 goto send_reply;
 900         }
 901
 902         session = caa_container_of(node, struct relay_session, session_n);
 903         if (cmd->session_id == session->id) {
 904                 /* Same viewer already attached, just send the stream list. */
 905                 send_streams = 1;
 906                 response.status = htobe32(VIEWER_ATTACH_OK);
 907         } else if (session->viewer_attached != 0) {
 908                 DBG("Already a viewer attached");
 909                 response.status = htobe32(VIEWER_ATTACH_ALREADY);
 910                 goto send_reply;
 911         } else if (session->live_timer == 0) {
 912                 DBG("Not live session");
 913                 response.status = htobe32(VIEWER_ATTACH_NOT_LIVE);
 914                 goto send_reply;
 915         } else {
 916                 session->viewer_attached++;
 917                 send_streams = 1;
 918                 response.status = htobe32(VIEWER_ATTACH_OK);
 919                 cmd->session_id = session->id;
 920                 cmd->session = session;
 921         }
 922
 923         switch (be32toh(request.seek)) {
 924         case VIEWER_SEEK_BEGINNING:
 925                 /* Default behaviour. */
 926                 break;
 927         case VIEWER_SEEK_LAST:
 928                 seek_last = 1;
 929                 break;
 930         default:
 931                 ERR("Wrong seek parameter");
 932                 response.status = htobe32(VIEWER_ATTACH_SEEK_ERR);
 933                 send_streams = 0;
 934                 goto send_reply;
 935         }
 936
 937         if (send_streams) {
 938                 /* We should only be there if we have a session to attach to. */
 939                 assert(session);
 940
 941                 /*
 942                  * Fill the viewer_streams_ht to count the number of streams
 943                  * ready to be sent and avoid concurrency issues on the
 944                  * relay_streams_ht and don't rely on a total session stream count.
 945                  */
 946                 cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, node, node) {
 947                         struct relay_viewer_stream *vstream;
 948
 949                         health_code_update();
 950
 951                         node = lttng_ht_iter_get_node_ulong(&iter);
 952                         if (!node) {
 953                                 continue;
 954                         }
 955                         stream = caa_container_of(node, struct relay_stream, stream_n);
 956                         if (stream->session != cmd->session) {
 957                                 continue;
 958                         }
 959                         nb_streams++;
 960
 961                         /*
 962                          * Don't send streams with no ctf_trace, they are not
 963                          * ready to be read.
 964                          */
 965                         if (!stream->ctf_trace || !stream->viewer_ready) {
 966                                 continue;
 967                         }
 968                         nb_streams_ready++;
 969
 970                         vstream = live_find_viewer_stream_by_id(stream->stream_handle);
 971                         if (!vstream) {
 972                                 ret = init_viewer_stream(stream, seek_last);
 973                                 if (ret < 0) {
 974                                         goto end_unlock;
 975                                 }
 976                         }
 977                 }
 978
 979                 /* We must have the same amount of existing stream and ready stream. */
 980                 if (nb_streams != nb_streams_ready) {
 981                         nb_streams = 0;
 982                 }
 983                 response.streams_count = htobe32(nb_streams);
 984         }
 985
 986 send_reply:
 987         health_code_update();
 988         ret = cmd->sock->ops->sendmsg(cmd->sock, &response, sizeof(response), 0);
 989         if (ret < 0) {
 990                 ERR("Relay sending viewer attach response");
 991                 goto end_unlock;
 992         }
 993         health_code_update();
 994
 995         /*
 996          * Unknown or empty session, just return gracefully, the viewer knows what
 997          * is happening.
 998          */
 999         if (!send_streams || !nb_streams) {
1000                 ret = 0;
1001                 goto end_unlock;
1002         }
1003
1004         /* We should only be there if we have a session to attach to. */
1005         assert(session);
1006         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, node, node) {
1007                 health_code_update();
1008
1009                 node64 = lttng_ht_iter_get_node_u64(&iter);
1010                 if (!node64) {
1011                         continue;
1012                 }
1013                 viewer_stream = caa_container_of(node64, struct relay_viewer_stream,
1014                                 stream_n);
1015                 if (viewer_stream->session_id != cmd->session->id) {
1016                         continue;
1017                 }
1018
1019                 send_stream.id = htobe64(viewer_stream->stream_handle);
1020                 send_stream.ctf_trace_id = htobe64(viewer_stream->ctf_trace->id);
1021                 send_stream.metadata_flag = htobe32(viewer_stream->metadata_flag);
1022                 strncpy(send_stream.path_name, viewer_stream->path_name,
1023                                 sizeof(send_stream.path_name));
1024                 strncpy(send_stream.channel_name, viewer_stream->channel_name,
1025                                 sizeof(send_stream.channel_name));
1026
1027                 ret = cmd->sock->ops->sendmsg(cmd->sock, &send_stream,
1028                                 sizeof(send_stream), 0);
1029                 if (ret < 0) {
1030                         ERR("Relay sending stream %" PRIu64, viewer_stream->stream_handle);
1031                         goto end_unlock;
1032                 }
1033                 DBG("Sent stream %" PRIu64 " to viewer", viewer_stream->stream_handle);
1034         }
1035         ret = 0;
1036
1037 end_unlock:
1038         rcu_read_unlock();
1039 end_no_session:
1040 error:
1041         return ret;
1042 }
1043
1044 /*
1045  * Get viewer stream from stream id.
1046  *
1047  * RCU read side lock MUST be acquired.
1048  */
1049 struct relay_viewer_stream *live_find_viewer_stream_by_id(uint64_t stream_id)
1050 {
1051         struct lttng_ht_node_u64 *node;
1052         struct lttng_ht_iter iter;
1053         struct relay_viewer_stream *stream = NULL;
1054
1055         lttng_ht_lookup(viewer_streams_ht, &stream_id, &iter);
1056         node = lttng_ht_iter_get_node_u64(&iter);
1057         if (node == NULL) {
1058                 DBG("Relay viewer stream %" PRIu64 " not found", stream_id);
1059                 goto end;
1060         }
1061         stream = caa_container_of(node, struct relay_viewer_stream, stream_n);
1062
1063 end:
1064         return stream;
1065 }
1066
1067 static
1068 void deferred_free_viewer_stream(struct rcu_head *head)
1069 {
1070         struct relay_viewer_stream *stream =
1071                 caa_container_of(head, struct relay_viewer_stream, rcu_node);
1072
1073         free(stream->path_name);
1074         free(stream->channel_name);
1075         free(stream);
1076 }
1077
1078 static
1079 void delete_viewer_stream(struct relay_viewer_stream *vstream)
1080 {
1081         int delret;
1082         struct lttng_ht_iter iter;
1083
1084         iter.iter.node = &vstream->stream_n.node;
1085         delret = lttng_ht_del(viewer_streams_ht, &iter);
1086         assert(!delret);
1087 }
1088
1089 static
1090 void destroy_viewer_stream(struct relay_viewer_stream *vstream)
1091 {
1092         unsigned long ret_ref;
1093         int ret;
1094
1095         assert(vstream);
1096         ret_ref = uatomic_add_return(&vstream->ctf_trace->refcount, -1);
1097         assert(ret_ref >= 0);
1098
1099         if (vstream->read_fd >= 0) {
1100                 ret = close(vstream->read_fd);
1101                 if (ret < 0) {
1102                         PERROR("close read_fd");
1103                 }
1104         }
1105         if (vstream->index_read_fd >= 0) {
1106                 ret = close(vstream->index_read_fd);
1107                 if (ret < 0) {
1108                         PERROR("close index_read_fd");
1109                 }
1110         }
1111
1112         /*
1113          * If the only stream left in the HT is the metadata stream,
1114          * we need to remove it because we won't detect a EOF for this
1115          * stream.
1116          */
1117         if (ret_ref == 1 && vstream->ctf_trace->viewer_metadata_stream) {
1118                 delete_viewer_stream(vstream->ctf_trace->viewer_metadata_stream);
1119                 destroy_viewer_stream(vstream->ctf_trace->viewer_metadata_stream);
1120                 vstream->ctf_trace->metadata_stream = NULL;
1121                 DBG("Freeing ctf_trace %" PRIu64, vstream->ctf_trace->id);
1122                 /*
1123                  * The streaming-side is already closed and we can't receive a new
1124                  * stream concurrently at this point (since the session is being
1125                  * destroyed), so when we detect the refcount equals 0, we are the
1126                  * only owners of the ctf_trace and we can free it ourself.
1127                  */
1128                 free(vstream->ctf_trace);
1129         }
1130
1131         call_rcu(&vstream->rcu_node, deferred_free_viewer_stream);
1132 }
1133
1134 /*
1135  * Send the next index for a stream.
1136  *
1137  * Return 0 on success or else a negative value.
1138  */
1139 static
1140 int viewer_get_next_index(struct relay_command *cmd,
1141                 struct lttng_ht *sessions_ht)
1142 {
1143         int ret;
1144         struct lttng_viewer_get_next_index request_index;
1145         struct lttng_viewer_index viewer_index;
1146         struct ctf_packet_index packet_index;
1147         struct relay_viewer_stream *vstream;
1148         struct relay_stream *rstream;
1149
1150         assert(cmd);
1151         assert(sessions_ht);
1152
1153         DBG("Viewer get next index");
1154
1155         if (cmd->version_check_done == 0) {
1156                 ERR("Trying to request index before version check");
1157                 ret = -1;
1158                 goto end_no_session;
1159         }
1160
1161         health_code_update();
1162         ret = cmd->sock->ops->recvmsg(cmd->sock, &request_index,
1163                         sizeof(request_index), 0);
1164         if (ret < 0 || ret != sizeof(request_index)) {
1165                 ret = -1;
1166                 ERR("Relay didn't receive the whole packet");
1167                 goto end;
1168         }
1169         health_code_update();
1170
1171         rcu_read_lock();
1172         vstream = live_find_viewer_stream_by_id(be64toh(request_index.stream_id));
1173         if (!vstream) {
1174                 ret = -1;
1175                 goto end_unlock;
1176         }
1177
1178         memset(&viewer_index, 0, sizeof(viewer_index));
1179
1180         /*
1181          * The viewer should not ask for index on metadata stream.
1182          */
1183         if (vstream->metadata_flag) {
1184                 viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1185                 goto send_reply;
1186         }
1187
1188         /* First time, we open the index file */
1189         if (vstream->index_read_fd < 0) {
1190                 ret = open_index(vstream);
1191                 if (ret == -ENOENT) {
1192                         /*
1193                          * The index is created only when the first data packet arrives, it
1194                          * might not be ready at the beginning of the session
1195                          */
1196                         viewer_index.status = htobe32(VIEWER_INDEX_RETRY);
1197                         goto send_reply;
1198                 } else if (ret < 0) {
1199                         viewer_index.status = htobe32(VIEWER_INDEX_ERR);
1200                         goto send_reply;
1201                 }
1202         }
1203
1204         rstream = relay_stream_find_by_id(vstream->stream_handle);
1205         if (rstream) {
1206                 if (vstream->abort_flag) {
1207                         /* Rotate on abort (overwrite). */
1208                         DBG("Viewer rotate because of overwrite");
1209                         ret = rotate_viewer_stream(vstream, rstream);
1210                         if (ret < 0) {
1211                                 goto end_unlock;
1212                         } else if (ret == 1) {
1213                                 viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1214                                 delete_viewer_stream(vstream);
1215                                 destroy_viewer_stream(vstream);
1216                                 goto send_reply;
1217                         }
1218                 }
1219                 pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
1220                 if (rstream->tracefile_count_current == vstream->tracefile_count_current) {
1221                         if (rstream->beacon_ts_end != -1ULL &&
1222                                 vstream->last_sent_index == rstream->total_index_received) {
1223                                 viewer_index.status = htobe32(VIEWER_INDEX_INACTIVE);
1224                                 viewer_index.timestamp_end = htobe64(rstream->beacon_ts_end);
1225                                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1226                                 goto send_reply;
1227                         /*
1228                          * Reader and writer are working in the same tracefile, so we care
1229                          * about the number of index received and sent. Otherwise, we read
1230                          * up to EOF.
1231                          */
1232                         } else if (rstream->total_index_received <= vstream->last_sent_index
1233                                         && !vstream->close_write_flag) {
1234                                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1235                                 /* No new index to send, retry later. */
1236                                 viewer_index.status = htobe32(VIEWER_INDEX_RETRY);
1237                                 goto send_reply;
1238                         }
1239                 }
1240                 pthread_mutex_unlock(&rstream->viewer_stream_rotation_lock);
1241         } else if (!rstream && vstream->close_write_flag &&
1242                         vstream->total_index_received == vstream->last_sent_index) {
1243                 /* Last index sent and current tracefile closed in write */
1244                 viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1245                 delete_viewer_stream(vstream);
1246                 destroy_viewer_stream(vstream);
1247                 goto send_reply;
1248         } else {
1249                 vstream->close_write_flag = 1;
1250         }
1251
1252         if (!vstream->ctf_trace->metadata_received ||
1253                         vstream->ctf_trace->metadata_received >
1254                         vstream->ctf_trace->metadata_sent) {
1255                 viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1256         }
1257
1258         pthread_mutex_lock(&vstream->overwrite_lock);
1259         if (vstream->abort_flag) {
1260                 /*
1261                  * The file is being overwritten by the writer, we cannot
1262                  * use it.
1263                  */
1264                 viewer_index.status = htobe32(VIEWER_INDEX_RETRY);
1265                 pthread_mutex_unlock(&vstream->overwrite_lock);
1266                 ret = rotate_viewer_stream(vstream, rstream);
1267                 if (ret < 0) {
1268                         goto end_unlock;
1269                 } else if (ret == 1) {
1270                         viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1271                         delete_viewer_stream(vstream);
1272                         destroy_viewer_stream(vstream);
1273                         goto send_reply;
1274                 }
1275                 goto send_reply;
1276         }
1277         ret = lttng_read(vstream->index_read_fd, &packet_index,
1278                         sizeof(packet_index));
1279         pthread_mutex_unlock(&vstream->overwrite_lock);
1280         if (ret < sizeof(packet_index)) {
1281                 /*
1282                  * The tracefile is closed in write, so we read up to EOF.
1283                  */
1284                 if (vstream->close_write_flag == 1) {
1285                         viewer_index.status = htobe32(VIEWER_INDEX_RETRY);
1286                         /* Rotate on normal EOF */
1287                         ret = rotate_viewer_stream(vstream, rstream);
1288                         if (ret < 0) {
1289                                 goto end_unlock;
1290                         } else if (ret == 1) {
1291                                 viewer_index.status = htobe32(VIEWER_INDEX_HUP);
1292                                 delete_viewer_stream(vstream);
1293                                 destroy_viewer_stream(vstream);
1294                                 goto send_reply;
1295                         }
1296                 } else {
1297                         PERROR("Relay reading index file %d",
1298                                         vstream->index_read_fd);
1299                         viewer_index.status = htobe32(VIEWER_INDEX_ERR);
1300                 }
1301                 goto send_reply;
1302         } else {
1303                 viewer_index.status = htobe32(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         ret = cmd->sock->ops->sendmsg(cmd->sock, &viewer_index,
1322                         sizeof(viewer_index), 0);
1323         if (ret < 0) {
1324                 ERR("Relay index to viewer");
1325                 goto end_unlock;
1326         }
1327         health_code_update();
1328
1329         DBG("Index %" PRIu64 "for stream %" PRIu64 "sent",
1330                         vstream->last_sent_index, vstream->stream_handle);
1331
1332 end_unlock:
1333         rcu_read_unlock();
1334
1335 end_no_session:
1336 end:
1337         return ret;
1338 }
1339
1340 /*
1341  * Send the next index for a stream
1342  *
1343  * Return 0 on success or else a negative value.
1344  */
1345 static
1346 int viewer_get_packet(struct relay_command *cmd)
1347 {
1348         int ret, send_data = 0;
1349         char *data = NULL;
1350         uint32_t len = 0;
1351         ssize_t read_len;
1352         struct lttng_viewer_get_packet get_packet_info;
1353         struct lttng_viewer_trace_packet reply;
1354         struct relay_viewer_stream *stream;
1355
1356         assert(cmd);
1357
1358         DBG2("Relay get data packet");
1359
1360         if (cmd->version_check_done == 0) {
1361                 ERR("Trying to get packet before version check");
1362                 ret = -1;
1363                 goto end;
1364         }
1365
1366         health_code_update();
1367         ret = cmd->sock->ops->recvmsg(cmd->sock, &get_packet_info,
1368                         sizeof(get_packet_info), 0);
1369         if (ret < 0 || ret != sizeof(get_packet_info)) {
1370                 ret = -1;
1371                 ERR("Relay didn't receive the whole packet");
1372                 goto end;
1373         }
1374         health_code_update();
1375
1376         /* From this point on, the error label can be reached. */
1377         memset(&reply, 0, sizeof(reply));
1378
1379         rcu_read_lock();
1380         stream = live_find_viewer_stream_by_id(be64toh(get_packet_info.stream_id));
1381         if (!stream) {
1382                 goto error;
1383         }
1384         assert(stream->ctf_trace);
1385
1386         /*
1387          * First time we read this stream, we need open the tracefile, we should
1388          * only arrive here if an index has already been sent to the viewer, so the
1389          * tracefile must exist, if it does not it is a fatal error.
1390          */
1391         if (stream->read_fd < 0) {
1392                 char fullpath[PATH_MAX];
1393
1394                 if (stream->tracefile_count > 0) {
1395                         ret = snprintf(fullpath, PATH_MAX, "%s/%s_%" PRIu64, stream->path_name,
1396                                         stream->channel_name,
1397                                         stream->tracefile_count_current);
1398                 } else {
1399                         ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1400                                         stream->channel_name);
1401                 }
1402                 if (ret < 0) {
1403                         goto error;
1404                 }
1405                 ret = open(fullpath, O_RDONLY);
1406                 if (ret < 0) {
1407                         PERROR("Relay opening trace file");
1408                         goto error;
1409                 }
1410                 stream->read_fd = ret;
1411         }
1412
1413         if (!stream->ctf_trace->metadata_received ||
1414                         stream->ctf_trace->metadata_received >
1415                         stream->ctf_trace->metadata_sent) {
1416                 reply.status = htobe32(VIEWER_GET_PACKET_ERR);
1417                 reply.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
1418                 goto send_reply;
1419         }
1420
1421         len = be32toh(get_packet_info.len);
1422         data = zmalloc(len);
1423         if (!data) {
1424                 PERROR("relay data zmalloc");
1425                 goto error;
1426         }
1427
1428         ret = lseek(stream->read_fd, be64toh(get_packet_info.offset), SEEK_SET);
1429         if (ret < 0) {
1430                 /*
1431                  * If the read fd was closed by the streaming side, the
1432                  * abort_flag will be set to 1, otherwise it is an error.
1433                  */
1434                 if (stream->abort_flag == 0) {
1435                         PERROR("lseek");
1436                         goto error;
1437                 }
1438                 reply.status = htobe32(VIEWER_GET_PACKET_EOF);
1439                 goto send_reply;
1440         }
1441         read_len = lttng_read(stream->read_fd, data, len);
1442         if (read_len < len) {
1443                 /*
1444                  * If the read fd was closed by the streaming side, the
1445                  * abort_flag will be set to 1, otherwise it is an error.
1446                  */
1447                 if (stream->abort_flag == 0) {
1448                         PERROR("Relay reading trace file, fd: %d, offset: %" PRIu64,
1449                                         stream->read_fd,
1450                                         be64toh(get_packet_info.offset));
1451                         goto error;
1452                 } else {
1453                         reply.status = htobe32(VIEWER_GET_PACKET_EOF);
1454                         goto send_reply;
1455                 }
1456         }
1457         reply.status = htobe32(VIEWER_GET_PACKET_OK);
1458         reply.len = htobe32(len);
1459         send_data = 1;
1460         goto send_reply;
1461
1462 error:
1463         reply.status = htobe32(VIEWER_GET_PACKET_ERR);
1464
1465 send_reply:
1466         reply.flags = htobe32(reply.flags);
1467
1468         health_code_update();
1469         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
1470         if (ret < 0) {
1471                 ERR("Relay data header to viewer");
1472                 goto end_unlock;
1473         }
1474         health_code_update();
1475
1476         if (send_data) {
1477                 health_code_update();
1478                 ret = cmd->sock->ops->sendmsg(cmd->sock, data, len, 0);
1479                 if (ret < 0) {
1480                         ERR("Relay send data to viewer");
1481                         goto end_unlock;
1482                 }
1483                 health_code_update();
1484         }
1485
1486         DBG("Sent %u bytes for stream %" PRIu64, len,
1487                         be64toh(get_packet_info.stream_id));
1488
1489 end_unlock:
1490         free(data);
1491         rcu_read_unlock();
1492
1493 end:
1494         return ret;
1495 }
1496
1497 /*
1498  * Send the session's metadata
1499  *
1500  * Return 0 on success else a negative value.
1501  */
1502 static
1503 int viewer_get_metadata(struct relay_command *cmd)
1504 {
1505         int ret = 0;
1506         ssize_t read_len;
1507         uint64_t len = 0;
1508         char *data = NULL;
1509         struct lttng_viewer_get_metadata request;
1510         struct lttng_viewer_metadata_packet reply;
1511         struct relay_viewer_stream *stream;
1512
1513         assert(cmd);
1514
1515         DBG("Relay get metadata");
1516
1517         if (cmd->version_check_done == 0) {
1518                 ERR("Trying to get metadata before version check");
1519                 ret = -1;
1520                 goto end;
1521         }
1522
1523         health_code_update();
1524         ret = cmd->sock->ops->recvmsg(cmd->sock, &request,
1525                         sizeof(request), 0);
1526         if (ret < 0 || ret != sizeof(request)) {
1527                 ret = -1;
1528                 ERR("Relay didn't receive the whole packet");
1529                 goto end;
1530         }
1531         health_code_update();
1532
1533         rcu_read_lock();
1534         stream = live_find_viewer_stream_by_id(be64toh(request.stream_id));
1535         if (!stream || !stream->metadata_flag) {
1536                 ERR("Invalid metadata stream");
1537                 goto error;
1538         }
1539         assert(stream->ctf_trace);
1540         assert(stream->ctf_trace->metadata_sent <=
1541                         stream->ctf_trace->metadata_received);
1542
1543         len = stream->ctf_trace->metadata_received -
1544                 stream->ctf_trace->metadata_sent;
1545         if (len == 0) {
1546                 reply.status = htobe32(VIEWER_NO_NEW_METADATA);
1547                 goto send_reply;
1548         }
1549
1550         /* first time, we open the metadata file */
1551         if (stream->read_fd < 0) {
1552                 char fullpath[PATH_MAX];
1553
1554                 ret = snprintf(fullpath, PATH_MAX, "%s/%s", stream->path_name,
1555                                 stream->channel_name);
1556                 if (ret < 0) {
1557                         goto error;
1558                 }
1559                 ret = open(fullpath, O_RDONLY);
1560                 if (ret < 0) {
1561                         PERROR("Relay opening metadata file");
1562                         goto error;
1563                 }
1564                 stream->read_fd = ret;
1565         }
1566
1567         reply.len = htobe64(len);
1568         data = zmalloc(len);
1569         if (!data) {
1570                 PERROR("viewer metadata zmalloc");
1571                 goto error;
1572         }
1573
1574         read_len = lttng_read(stream->read_fd, data, len);
1575         if (read_len < len) {
1576                 PERROR("Relay reading metadata file");
1577                 goto error;
1578         }
1579         stream->ctf_trace->metadata_sent += read_len;
1580         reply.status = htobe32(VIEWER_METADATA_OK);
1581         goto send_reply;
1582
1583 error:
1584         reply.status = htobe32(VIEWER_METADATA_ERR);
1585
1586 send_reply:
1587         health_code_update();
1588         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
1589         if (ret < 0) {
1590                 ERR("Relay data header to viewer");
1591                 goto end_unlock;
1592         }
1593         health_code_update();
1594
1595         if (len > 0) {
1596                 ret = cmd->sock->ops->sendmsg(cmd->sock, data, len, 0);
1597                 if (ret < 0) {
1598                         ERR("Relay send data to viewer");
1599                         goto end_unlock;
1600                 }
1601         }
1602
1603         DBG("Sent %" PRIu64 " bytes of metadata for stream %" PRIu64, len,
1604                         be64toh(request.stream_id));
1605
1606         DBG("Metadata sent");
1607
1608 end_unlock:
1609         free(data);
1610         rcu_read_unlock();
1611 end:
1612         return ret;
1613 }
1614
1615 /*
1616  * live_relay_unknown_command: send -1 if received unknown command
1617  */
1618 static
1619 void live_relay_unknown_command(struct relay_command *cmd)
1620 {
1621         struct lttcomm_relayd_generic_reply reply;
1622         int ret;
1623
1624         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1625         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
1626                         sizeof(struct lttcomm_relayd_generic_reply), 0);
1627         if (ret < 0) {
1628                 ERR("Relay sending unknown command");
1629         }
1630 }
1631
1632 /*
1633  * Process the commands received on the control socket
1634  */
1635 static
1636 int process_control(struct lttng_viewer_cmd *recv_hdr,
1637                 struct relay_command *cmd, struct lttng_ht *sessions_ht)
1638 {
1639         int ret = 0;
1640
1641         switch (be32toh(recv_hdr->cmd)) {
1642         case VIEWER_CONNECT:
1643                 ret = viewer_connect(cmd);
1644                 break;
1645         case VIEWER_LIST_SESSIONS:
1646                 ret = viewer_list_sessions(cmd, sessions_ht);
1647                 break;
1648         case VIEWER_ATTACH_SESSION:
1649                 ret = viewer_attach_session(cmd, sessions_ht);
1650                 break;
1651         case VIEWER_GET_NEXT_INDEX:
1652                 ret = viewer_get_next_index(cmd, sessions_ht);
1653                 break;
1654         case VIEWER_GET_PACKET:
1655                 ret = viewer_get_packet(cmd);
1656                 break;
1657         case VIEWER_GET_METADATA:
1658                 ret = viewer_get_metadata(cmd);
1659                 break;
1660         default:
1661                 ERR("Received unknown viewer command (%u)", be32toh(recv_hdr->cmd));
1662                 live_relay_unknown_command(cmd);
1663                 ret = -1;
1664                 goto end;
1665         }
1666
1667 end:
1668         return ret;
1669 }
1670
1671 static
1672 void cleanup_poll_connection(struct lttng_poll_event *events, int pollfd)
1673 {
1674         int ret;
1675
1676         assert(events);
1677
1678         lttng_poll_del(events, pollfd);
1679
1680         ret = close(pollfd);
1681         if (ret < 0) {
1682                 ERR("Closing pollfd %d", pollfd);
1683         }
1684 }
1685
1686 /*
1687  * Create and add connection to the given hash table.
1688  *
1689  * Return poll add value or else -1 on error.
1690  */
1691 static
1692 int add_connection(int fd, struct lttng_poll_event *events,
1693                 struct lttng_ht *relay_connections_ht)
1694 {
1695         int ret;
1696         struct relay_command *relay_connection;
1697
1698         assert(events);
1699         assert(relay_connections_ht);
1700
1701         relay_connection = zmalloc(sizeof(struct relay_command));
1702         if (relay_connection == NULL) {
1703                 PERROR("Relay command zmalloc");
1704                 goto error;
1705         }
1706
1707         ret = lttng_read(fd, relay_connection, sizeof(*relay_connection));
1708         if (ret < sizeof(*relay_connection)) {
1709                 PERROR("read relay cmd pipe");
1710                 goto error_read;
1711         }
1712
1713         lttng_ht_node_init_ulong(&relay_connection->sock_n,
1714                         (unsigned long) relay_connection->sock->fd);
1715         rcu_read_lock();
1716         lttng_ht_add_unique_ulong(relay_connections_ht,
1717                         &relay_connection->sock_n);
1718         rcu_read_unlock();
1719
1720         return lttng_poll_add(events, relay_connection->sock->fd,
1721                         LPOLLIN | LPOLLRDHUP);
1722
1723 error_read:
1724         free(relay_connection);
1725 error:
1726         return -1;
1727 }
1728
1729 static
1730 void deferred_free_connection(struct rcu_head *head)
1731 {
1732         struct relay_command *relay_connection =
1733                 caa_container_of(head, struct relay_command, rcu_node);
1734
1735         if (relay_connection->session &&
1736                         relay_connection->session->viewer_attached > 0) {
1737                 relay_connection->session->viewer_attached--;
1738         }
1739         lttcomm_destroy_sock(relay_connection->sock);
1740         free(relay_connection);
1741 }
1742
1743 /*
1744  * Delete all streams for a specific session ID.
1745  */
1746 static
1747 void viewer_del_streams(uint64_t session_id)
1748 {
1749         struct relay_viewer_stream *stream;
1750         struct lttng_ht_iter iter;
1751
1752         rcu_read_lock();
1753         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, stream,
1754                         stream_n.node) {
1755                 health_code_update();
1756
1757                 if (stream->session_id != session_id) {
1758                         continue;
1759                 }
1760
1761                 delete_viewer_stream(stream);
1762                 assert(stream->ctf_trace);
1763
1764                 if (stream->metadata_flag) {
1765                         /*
1766                          * The metadata viewer stream is destroyed once the refcount on the
1767                          * ctf trace goes to 0 in the destroy stream function thus there is
1768                          * no explicit call to that function here.
1769                          */
1770                         stream->ctf_trace->metadata_sent = 0;
1771                         stream->ctf_trace->viewer_metadata_stream = NULL;
1772                 } else {
1773                         destroy_viewer_stream(stream);
1774                 }
1775         }
1776         rcu_read_unlock();
1777 }
1778
1779 /*
1780  * Delete and free a connection.
1781  *
1782  * RCU read side lock MUST be acquired.
1783  */
1784 static
1785 void del_connection(struct lttng_ht *relay_connections_ht,
1786                 struct lttng_ht_iter *iter, struct relay_command *relay_connection)
1787 {
1788         int ret;
1789
1790         assert(relay_connections_ht);
1791         assert(iter);
1792         assert(relay_connection);
1793
1794         DBG("Cleaning connection of session ID %" PRIu64,
1795                         relay_connection->session_id);
1796
1797         ret = lttng_ht_del(relay_connections_ht, iter);
1798         assert(!ret);
1799
1800         viewer_del_streams(relay_connection->session_id);
1801
1802         call_rcu(&relay_connection->rcu_node, deferred_free_connection);
1803 }
1804
1805 /*
1806  * This thread does the actual work
1807  */
1808 static
1809 void *thread_worker(void *data)
1810 {
1811         int ret, err = -1;
1812         uint32_t nb_fd;
1813         struct relay_command *relay_connection;
1814         struct lttng_poll_event events;
1815         struct lttng_ht *relay_connections_ht;
1816         struct lttng_ht_node_ulong *node;
1817         struct lttng_ht_iter iter;
1818         struct lttng_viewer_cmd recv_hdr;
1819         struct relay_local_data *relay_ctx = (struct relay_local_data *) data;
1820         struct lttng_ht *sessions_ht = relay_ctx->sessions_ht;
1821
1822         DBG("[thread] Live viewer relay worker started");
1823
1824         rcu_register_thread();
1825
1826         health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
1827
1828         /* table of connections indexed on socket */
1829         relay_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1830         if (!relay_connections_ht) {
1831                 goto relay_connections_ht_error;
1832         }
1833
1834         ret = create_thread_poll_set(&events, 2);
1835         if (ret < 0) {
1836                 goto error_poll_create;
1837         }
1838
1839         ret = lttng_poll_add(&events, live_relay_cmd_pipe[0], LPOLLIN | LPOLLRDHUP);
1840         if (ret < 0) {
1841                 goto error;
1842         }
1843
1844 restart:
1845         while (1) {
1846                 int i;
1847
1848                 health_code_update();
1849
1850                 /* Infinite blocking call, waiting for transmission */
1851                 DBG3("Relayd live viewer worker thread polling...");
1852                 health_poll_entry();
1853                 ret = lttng_poll_wait(&events, -1);
1854                 health_poll_exit();
1855                 if (ret < 0) {
1856                         /*
1857                          * Restart interrupted system call.
1858                          */
1859                         if (errno == EINTR) {
1860                                 goto restart;
1861                         }
1862                         goto error;
1863                 }
1864
1865                 nb_fd = ret;
1866
1867                 /*
1868                  * Process control. The control connection is prioritised so we don't
1869                  * starve it with high throughput tracing data on the data
1870                  * connection.
1871                  */
1872                 for (i = 0; i < nb_fd; i++) {
1873                         /* Fetch once the poll data */
1874                         uint32_t revents = LTTNG_POLL_GETEV(&events, i);
1875                         int pollfd = LTTNG_POLL_GETFD(&events, i);
1876
1877                         health_code_update();
1878
1879                         /* Thread quit pipe has been closed. Killing thread. */
1880                         ret = check_thread_quit_pipe(pollfd, revents);
1881                         if (ret) {
1882                                 err = 0;
1883                                 goto exit;
1884                         }
1885
1886                         /* Inspect the relay cmd pipe for new connection */
1887                         if (pollfd == live_relay_cmd_pipe[0]) {
1888                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1889                                         ERR("Relay live pipe error");
1890                                         goto error;
1891                                 } else if (revents & LPOLLIN) {
1892                                         DBG("Relay live viewer command received");
1893                                         ret = add_connection(live_relay_cmd_pipe[0],
1894                                                         &events, relay_connections_ht);
1895                                         if (ret < 0) {
1896                                                 goto error;
1897                                         }
1898                                 }
1899                         } else if (revents) {
1900                                 rcu_read_lock();
1901                                 lttng_ht_lookup(relay_connections_ht,
1902                                                 (void *)((unsigned long) pollfd), &iter);
1903                                 node = lttng_ht_iter_get_node_ulong(&iter);
1904                                 if (node == NULL) {
1905                                         DBG2("Relay viewer sock %d not found", pollfd);
1906                                         rcu_read_unlock();
1907                                         goto error;
1908                                 }
1909                                 relay_connection = caa_container_of(node, struct relay_command,
1910                                                 sock_n);
1911
1912                                 if (revents & (LPOLLERR)) {
1913                                         cleanup_poll_connection(&events, pollfd);
1914                                         del_connection(relay_connections_ht, &iter,
1915                                                         relay_connection);
1916                                 } else if (revents & (LPOLLHUP | LPOLLRDHUP)) {
1917                                         DBG("Viewer socket %d hung up", pollfd);
1918                                         cleanup_poll_connection(&events, pollfd);
1919                                         del_connection(relay_connections_ht, &iter,
1920                                                         relay_connection);
1921                                 } else if (revents & LPOLLIN) {
1922                                         ret = relay_connection->sock->ops->recvmsg(
1923                                                         relay_connection->sock, &recv_hdr,
1924                                                         sizeof(struct lttng_viewer_cmd),
1925                                                         0);
1926                                         /* connection closed */
1927                                         if (ret <= 0) {
1928                                                 cleanup_poll_connection(&events, pollfd);
1929                                                 del_connection(relay_connections_ht, &iter,
1930                                                                 relay_connection);
1931                                                 DBG("Viewer control connection closed with %d",
1932                                                                 pollfd);
1933                                         } else {
1934                                                 if (relay_connection->session) {
1935                                                         DBG2("Relay viewer worker receiving data for "
1936                                                                         "session: %" PRIu64,
1937                                                                         relay_connection->session->id);
1938                                                 }
1939                                                 ret = process_control(&recv_hdr, relay_connection,
1940                                                                 sessions_ht);
1941                                                 if (ret < 0) {
1942                                                         /* Clear the session on error. */
1943                                                         cleanup_poll_connection(&events, pollfd);
1944                                                         del_connection(relay_connections_ht, &iter,
1945                                                                         relay_connection);
1946                                                         DBG("Viewer connection closed with %d", pollfd);
1947                                                 }
1948                                         }
1949                                 }
1950                                 rcu_read_unlock();
1951                         }
1952                 }
1953         }
1954
1955 exit:
1956 error:
1957         lttng_poll_clean(&events);
1958
1959         /* empty the hash table and free the memory */
1960         rcu_read_lock();
1961         cds_lfht_for_each_entry(relay_connections_ht->ht, &iter.iter, node, node) {
1962                 health_code_update();
1963
1964                 node = lttng_ht_iter_get_node_ulong(&iter);
1965                 if (!node) {
1966                         continue;
1967                 }
1968
1969                 relay_connection = caa_container_of(node, struct relay_command,
1970                                 sock_n);
1971                 del_connection(relay_connections_ht, &iter, relay_connection);
1972         }
1973         rcu_read_unlock();
1974 error_poll_create:
1975         lttng_ht_destroy(relay_connections_ht);
1976 relay_connections_ht_error:
1977         /* Close relay cmd pipes */
1978         utils_close_pipe(live_relay_cmd_pipe);
1979         if (err) {
1980                 DBG("Viewer worker thread exited with error");
1981         }
1982         DBG("Viewer worker thread cleanup complete");
1983         if (err) {
1984                 health_error();
1985                 ERR("Health error occurred in %s", __func__);
1986         }
1987         health_unregister(health_relayd);
1988         stop_threads();
1989         rcu_unregister_thread();
1990         return NULL;
1991 }
1992
1993 /*
1994  * Create the relay command pipe to wake thread_manage_apps.
1995  * Closed in cleanup().
1996  */
1997 static int create_relay_cmd_pipe(void)
1998 {
1999         int ret;
2000
2001         ret = utils_create_pipe_cloexec(live_relay_cmd_pipe);
2002
2003         return ret;
2004 }
2005
2006 void live_stop_threads(void)
2007 {
2008         int ret;
2009         void *status;
2010
2011         stop_threads();
2012
2013         ret = pthread_join(live_listener_thread, &status);
2014         if (ret != 0) {
2015                 PERROR("pthread_join live listener");
2016                 goto error;     /* join error, exit without cleanup */
2017         }
2018
2019         ret = pthread_join(live_worker_thread, &status);
2020         if (ret != 0) {
2021                 PERROR("pthread_join live worker");
2022                 goto error;     /* join error, exit without cleanup */
2023         }
2024
2025         ret = pthread_join(live_dispatcher_thread, &status);
2026         if (ret != 0) {
2027                 PERROR("pthread_join live dispatcher");
2028                 goto error;     /* join error, exit without cleanup */
2029         }
2030
2031         cleanup();
2032
2033 error:
2034         return;
2035 }
2036
2037 /*
2038  * main
2039  */
2040 int live_start_threads(struct lttng_uri *uri,
2041                 struct relay_local_data *relay_ctx)
2042 {
2043         int ret = 0;
2044         void *status;
2045         int is_root;
2046
2047         assert(uri);
2048         live_uri = uri;
2049
2050         /* Check if daemon is UID = 0 */
2051         is_root = !getuid();
2052
2053         if (!is_root) {
2054                 if (live_uri->port < 1024) {
2055                         ERR("Need to be root to use ports < 1024");
2056                         ret = -1;
2057                         goto exit;
2058                 }
2059         }
2060
2061         /* Setup the thread apps communication pipe. */
2062         if ((ret = create_relay_cmd_pipe()) < 0) {
2063                 goto exit;
2064         }
2065
2066         /* Init relay command queue. */
2067         cds_wfq_init(&viewer_cmd_queue.queue);
2068
2069         /* Set up max poll set size */
2070         lttng_poll_set_max_size();
2071
2072         /* Setup the dispatcher thread */
2073         ret = pthread_create(&live_dispatcher_thread, NULL,
2074                         thread_dispatcher, (void *) NULL);
2075         if (ret != 0) {
2076                 PERROR("pthread_create viewer dispatcher");
2077                 goto exit_dispatcher;
2078         }
2079
2080         /* Setup the worker thread */
2081         ret = pthread_create(&live_worker_thread, NULL,
2082                         thread_worker, relay_ctx);
2083         if (ret != 0) {
2084                 PERROR("pthread_create viewer worker");
2085                 goto exit_worker;
2086         }
2087
2088         /* Setup the listener thread */
2089         ret = pthread_create(&live_listener_thread, NULL,
2090                         thread_listener, (void *) NULL);
2091         if (ret != 0) {
2092                 PERROR("pthread_create viewer listener");
2093                 goto exit_listener;
2094         }
2095
2096         ret = 0;
2097         goto end;
2098
2099 exit_listener:
2100         ret = pthread_join(live_listener_thread, &status);
2101         if (ret != 0) {
2102                 PERROR("pthread_join live listener");
2103                 goto error;     /* join error, exit without cleanup */
2104         }
2105
2106 exit_worker:
2107         ret = pthread_join(live_worker_thread, &status);
2108         if (ret != 0) {
2109                 PERROR("pthread_join live worker");
2110                 goto error;     /* join error, exit without cleanup */
2111         }
2112
2113 exit_dispatcher:
2114         ret = pthread_join(live_dispatcher_thread, &status);
2115         if (ret != 0) {
2116                 PERROR("pthread_join live dispatcher");
2117                 goto error;     /* join error, exit without cleanup */
2118         }
2119
2120 exit:
2121         cleanup();
2122
2123 end:
2124 error:
2125         return ret;
2126 }