src/bin/lttng-relayd/main.c

   1 /*
   2  * Copyright (C) 2012 - 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/hashtable/hashtable.h>
  51 #include <common/sessiond-comm/relayd.h>
  52 #include <common/uri.h>
  53 #include <common/utils.h>
  54
  55 #include "lttng-relayd.h"
  56
  57 /* command line options */
  58 static int opt_daemon;
  59 static char *opt_output_path;
  60 static struct lttng_uri *control_uri;
  61 static struct lttng_uri *data_uri;
  62
  63 const char *progname;
  64 static int is_root;                     /* Set to 1 if the daemon is running as root */
  65
  66 /*
  67  * Quit pipe for all threads. This permits a single cancellation point
  68  * for all threads when receiving an event on the pipe.
  69  */
  70 static int thread_quit_pipe[2] = { -1, -1 };
  71
  72 /*
  73  * This pipe is used to inform the worker thread that a command is queued and
  74  * ready to be processed.
  75  */
  76 static int relay_cmd_pipe[2] = { -1, -1 };
  77
  78 /* Shared between threads */
  79 static int dispatch_thread_exit;
  80
  81 static pthread_t listener_thread;
  82 static pthread_t dispatcher_thread;
  83 static pthread_t worker_thread;
  84
  85 static uint64_t last_relay_stream_id;
  86 static uint64_t last_relay_session_id;
  87
  88 /*
  89  * Relay command queue.
  90  *
  91  * The relay_thread_listener and relay_thread_dispatcher communicate with this
  92  * queue.
  93  */
  94 static struct relay_cmd_queue relay_cmd_queue;
  95
  96 /* buffer allocated at startup, used to store the trace data */
  97 static char *data_buffer;
  98 static unsigned int data_buffer_size;
  99
 100 /*
 101  * usage function on stderr
 102  */
 103 static
 104 void usage(void)
 105 {
 106         fprintf(stderr, "Usage: %s OPTIONS\n\nOptions:\n", progname);
 107         fprintf(stderr, "  -h, --help                         Display this usage.\n");
 108         fprintf(stderr, "  -d, --daemonize                    Start as a daemon.\n");
 109         fprintf(stderr, "  -C, --control-port                 Control port listening (URI)\n");
 110         fprintf(stderr, "  -D, --data-port                    Data port listening (URI)\n");
 111         fprintf(stderr, "  -o, --output                       Output path for traces (PATH)\n");
 112         fprintf(stderr, "  -v, --verbose                      Verbose mode. Activate DBG() macro.\n");
 113 }
 114
 115 static
 116 int parse_args(int argc, char **argv)
 117 {
 118         int c;
 119         int ret = 0;
 120         char *default_address;
 121
 122         static struct option long_options[] = {
 123                 { "control-port", 1, 0, 'C', },
 124                 { "data-port", 1, 0, 'D', },
 125                 { "daemonize", 0, 0, 'd', },
 126                 { "help", 0, 0, 'h', },
 127                 { "output", 1, 0, 'o', },
 128                 { "verbose", 0, 0, 'v', },
 129                 { NULL, 0, 0, 0, },
 130         };
 131
 132         while (1) {
 133                 int option_index = 0;
 134                 c = getopt_long(argc, argv, "dhv" "C:D:o:",
 135                                 long_options, &option_index);
 136                 if (c == -1) {
 137                         break;
 138                 }
 139
 140                 switch (c) {
 141                 case 0:
 142                         fprintf(stderr, "option %s", long_options[option_index].name);
 143                         if (optarg) {
 144                                 fprintf(stderr, " with arg %s\n", optarg);
 145                         }
 146                         break;
 147                 case 'C':
 148                         ret = uri_parse(optarg, &control_uri);
 149                         if (ret < 0) {
 150                                 ERR("Invalid control URI specified");
 151                                 goto exit;
 152                         }
 153                         if (control_uri->port == 0) {
 154                                 control_uri->port = DEFAULT_NETWORK_CONTROL_PORT;
 155                         }
 156                         break;
 157                 case 'D':
 158                         ret = uri_parse(optarg, &data_uri);
 159                         if (ret < 0) {
 160                                 ERR("Invalid data URI specified");
 161                                 goto exit;
 162                         }
 163                         if (data_uri->port == 0) {
 164                                 data_uri->port = DEFAULT_NETWORK_DATA_PORT;
 165                         }
 166                         break;
 167                 case 'd':
 168                         opt_daemon = 1;
 169                         break;
 170                 case 'h':
 171                         usage();
 172                         exit(EXIT_FAILURE);
 173                 case 'o':
 174                         ret = asprintf(&opt_output_path, "%s", optarg);
 175                         if (ret < 0) {
 176                                 PERROR("asprintf opt_output_path");
 177                                 goto exit;
 178                         }
 179                         break;
 180                 case 'v':
 181                         /* Verbose level can increase using multiple -v */
 182                         lttng_opt_verbose += 1;
 183                         break;
 184                 default:
 185                         /* Unknown option or other error.
 186                          * Error is printed by getopt, just return */
 187                         ret = -1;
 188                         goto exit;
 189                 }
 190         }
 191
 192         /* assign default values */
 193         if (control_uri == NULL) {
 194                 ret = asprintf(&default_address, "tcp://0.0.0.0:%d",
 195                                 DEFAULT_NETWORK_CONTROL_PORT);
 196                 if (ret < 0) {
 197                         PERROR("asprintf default data address");
 198                         goto exit;
 199                 }
 200
 201                 ret = uri_parse(default_address, &control_uri);
 202                 free(default_address);
 203                 if (ret < 0) {
 204                         ERR("Invalid control URI specified");
 205                         goto exit;
 206                 }
 207         }
 208         if (data_uri == NULL) {
 209                 ret = asprintf(&default_address, "tcp://0.0.0.0:%d",
 210                                 DEFAULT_NETWORK_DATA_PORT);
 211                 if (ret < 0) {
 212                         PERROR("asprintf default data address");
 213                         goto exit;
 214                 }
 215
 216                 ret = uri_parse(default_address, &data_uri);
 217                 free(default_address);
 218                 if (ret < 0) {
 219                         ERR("Invalid data URI specified");
 220                         goto exit;
 221                 }
 222         }
 223
 224 exit:
 225         return ret;
 226 }
 227
 228 /*
 229  * Cleanup the daemon
 230  */
 231 static
 232 void cleanup(void)
 233 {
 234         DBG("Cleaning up");
 235
 236         /* free the dynamically allocated opt_output_path */
 237         free(opt_output_path);
 238
 239         /* Close thread quit pipes */
 240         utils_close_pipe(thread_quit_pipe);
 241
 242         uri_free(control_uri);
 243         uri_free(data_uri);
 244 }
 245
 246 /*
 247  * Write to writable pipe used to notify a thread.
 248  */
 249 static
 250 int notify_thread_pipe(int wpipe)
 251 {
 252         int ret;
 253
 254         do {
 255                 ret = write(wpipe, "!", 1);
 256         } while (ret < 0 && errno == EINTR);
 257         if (ret < 0) {
 258                 PERROR("write poll pipe");
 259         }
 260
 261         return ret;
 262 }
 263
 264 /*
 265  * Stop all threads by closing the thread quit pipe.
 266  */
 267 static
 268 void stop_threads(void)
 269 {
 270         int ret;
 271
 272         /* Stopping all threads */
 273         DBG("Terminating all threads");
 274         ret = notify_thread_pipe(thread_quit_pipe[1]);
 275         if (ret < 0) {
 276                 ERR("write error on thread quit pipe");
 277         }
 278
 279         /* Dispatch thread */
 280         CMM_STORE_SHARED(dispatch_thread_exit, 1);
 281         futex_nto1_wake(&relay_cmd_queue.futex);
 282 }
 283
 284 /*
 285  * Signal handler for the daemon
 286  *
 287  * Simply stop all worker threads, leaving main() return gracefully after
 288  * joining all threads and calling cleanup().
 289  */
 290 static
 291 void sighandler(int sig)
 292 {
 293         switch (sig) {
 294         case SIGPIPE:
 295                 DBG("SIGPIPE caught");
 296                 return;
 297         case SIGINT:
 298                 DBG("SIGINT caught");
 299                 stop_threads();
 300                 break;
 301         case SIGTERM:
 302                 DBG("SIGTERM caught");
 303                 stop_threads();
 304                 break;
 305         default:
 306                 break;
 307         }
 308 }
 309
 310 /*
 311  * Setup signal handler for :
 312  *              SIGINT, SIGTERM, SIGPIPE
 313  */
 314 static
 315 int set_signal_handler(void)
 316 {
 317         int ret = 0;
 318         struct sigaction sa;
 319         sigset_t sigset;
 320
 321         if ((ret = sigemptyset(&sigset)) < 0) {
 322                 PERROR("sigemptyset");
 323                 return ret;
 324         }
 325
 326         sa.sa_handler = sighandler;
 327         sa.sa_mask = sigset;
 328         sa.sa_flags = 0;
 329         if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
 330                 PERROR("sigaction");
 331                 return ret;
 332         }
 333
 334         if ((ret = sigaction(SIGINT, &sa, NULL)) < 0) {
 335                 PERROR("sigaction");
 336                 return ret;
 337         }
 338
 339         if ((ret = sigaction(SIGPIPE, &sa, NULL)) < 0) {
 340                 PERROR("sigaction");
 341                 return ret;
 342         }
 343
 344         DBG("Signal handler set for SIGTERM, SIGPIPE and SIGINT");
 345
 346         return ret;
 347 }
 348
 349 /*
 350  * Init thread quit pipe.
 351  *
 352  * Return -1 on error or 0 if all pipes are created.
 353  */
 354 static
 355 int init_thread_quit_pipe(void)
 356 {
 357         int ret;
 358
 359         ret = utils_create_pipe_cloexec(thread_quit_pipe);
 360
 361         return ret;
 362 }
 363
 364 /*
 365  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
 366  */
 367 static
 368 int create_thread_poll_set(struct lttng_poll_event *events, int size)
 369 {
 370         int ret;
 371
 372         if (events == NULL || size == 0) {
 373                 ret = -1;
 374                 goto error;
 375         }
 376
 377         ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
 378         if (ret < 0) {
 379                 goto error;
 380         }
 381
 382         /* Add quit pipe */
 383         ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN);
 384         if (ret < 0) {
 385                 goto error;
 386         }
 387
 388         return 0;
 389
 390 error:
 391         return ret;
 392 }
 393
 394 /*
 395  * Check if the thread quit pipe was triggered.
 396  *
 397  * Return 1 if it was triggered else 0;
 398  */
 399 static
 400 int check_thread_quit_pipe(int fd, uint32_t events)
 401 {
 402         if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
 403                 return 1;
 404         }
 405
 406         return 0;
 407 }
 408
 409 /*
 410  * Create and init socket from uri.
 411  */
 412 static
 413 struct lttcomm_sock *relay_init_sock(struct lttng_uri *uri)
 414 {
 415         int ret;
 416         struct lttcomm_sock *sock = NULL;
 417
 418         sock = lttcomm_alloc_sock_from_uri(uri);
 419         if (sock == NULL) {
 420                 ERR("Allocating socket");
 421                 goto error;
 422         }
 423
 424         ret = lttcomm_create_sock(sock);
 425         if (ret < 0) {
 426                 goto error;
 427         }
 428         DBG("Listening on sock %d", sock->fd);
 429
 430         ret = sock->ops->bind(sock);
 431         if (ret < 0) {
 432                 goto error;
 433         }
 434
 435         ret = sock->ops->listen(sock, -1);
 436         if (ret < 0) {
 437                 goto error;
 438
 439         }
 440
 441         return sock;
 442
 443 error:
 444         if (sock) {
 445                 lttcomm_destroy_sock(sock);
 446         }
 447         return NULL;
 448 }
 449
 450 /*
 451  * Return nonzero if stream needs to be closed.
 452  */
 453 static
 454 int close_stream_check(struct relay_stream *stream)
 455 {
 456
 457         if (stream->close_flag && stream->prev_seq == stream->last_net_seq_num) {
 458                 return 1;
 459         }
 460         return 0;
 461 }
 462
 463 /*
 464  * This thread manages the listening for new connections on the network
 465  */
 466 static
 467 void *relay_thread_listener(void *data)
 468 {
 469         int i, ret, pollfd, err = -1;
 470         int val = 1;
 471         uint32_t revents, nb_fd;
 472         struct lttng_poll_event events;
 473         struct lttcomm_sock *control_sock, *data_sock;
 474
 475         DBG("[thread] Relay listener started");
 476
 477         control_sock = relay_init_sock(control_uri);
 478         if (!control_sock) {
 479                 goto error_sock_control;
 480         }
 481
 482         data_sock = relay_init_sock(data_uri);
 483         if (!data_sock) {
 484                 goto error_sock_relay;
 485         }
 486
 487         /*
 488          * Pass 3 as size here for the thread quit pipe, control and data socket.
 489          */
 490         ret = create_thread_poll_set(&events, 3);
 491         if (ret < 0) {
 492                 goto error_create_poll;
 493         }
 494
 495         /* Add the control socket */
 496         ret = lttng_poll_add(&events, control_sock->fd, LPOLLIN | LPOLLRDHUP);
 497         if (ret < 0) {
 498                 goto error_poll_add;
 499         }
 500
 501         /* Add the data socket */
 502         ret = lttng_poll_add(&events, data_sock->fd, LPOLLIN | LPOLLRDHUP);
 503         if (ret < 0) {
 504                 goto error_poll_add;
 505         }
 506
 507         while (1) {
 508                 DBG("Listener accepting connections");
 509
 510                 nb_fd = LTTNG_POLL_GETNB(&events);
 511
 512 restart:
 513                 ret = lttng_poll_wait(&events, -1);
 514                 if (ret < 0) {
 515                         /*
 516                          * Restart interrupted system call.
 517                          */
 518                         if (errno == EINTR) {
 519                                 goto restart;
 520                         }
 521                         goto error;
 522                 }
 523
 524                 DBG("Relay new connection received");
 525                 for (i = 0; i < nb_fd; i++) {
 526                         /* Fetch once the poll data */
 527                         revents = LTTNG_POLL_GETEV(&events, i);
 528                         pollfd = LTTNG_POLL_GETFD(&events, i);
 529
 530                         /* Thread quit pipe has been closed. Killing thread. */
 531                         ret = check_thread_quit_pipe(pollfd, revents);
 532                         if (ret) {
 533                                 err = 0;
 534                                 goto exit;
 535                         }
 536
 537                         if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 538                                 ERR("socket poll error");
 539                                 goto error;
 540                         } else if (revents & LPOLLIN) {
 541                                 /*
 542                                  * Get allocated in this thread,
 543                                  * enqueued to a global queue, dequeued
 544                                  * and freed in the worker thread.
 545                                  */
 546                                 struct relay_command *relay_cmd;
 547                                 struct lttcomm_sock *newsock;
 548
 549                                 relay_cmd = zmalloc(sizeof(struct relay_command));
 550                                 if (relay_cmd == NULL) {
 551                                         PERROR("relay command zmalloc");
 552                                         goto error;
 553                                 }
 554
 555                                 if (pollfd == data_sock->fd) {
 556                                         newsock = data_sock->ops->accept(data_sock);
 557                                         if (!newsock) {
 558                                                 PERROR("accepting data sock");
 559                                                 free(relay_cmd);
 560                                                 goto error;
 561                                         }
 562                                         relay_cmd->type = RELAY_DATA;
 563                                         DBG("Relay data connection accepted, socket %d", newsock->fd);
 564                                 } else {
 565                                         assert(pollfd == control_sock->fd);
 566                                         newsock = control_sock->ops->accept(control_sock);
 567                                         if (!newsock) {
 568                                                 PERROR("accepting control sock");
 569                                                 free(relay_cmd);
 570                                                 goto error;
 571                                         }
 572                                         relay_cmd->type = RELAY_CONTROL;
 573                                         DBG("Relay control connection accepted, socket %d", newsock->fd);
 574                                 }
 575                                 ret = setsockopt(newsock->fd, SOL_SOCKET, SO_REUSEADDR,
 576                                                 &val, sizeof(int));
 577                                 if (ret < 0) {
 578                                         PERROR("setsockopt inet");
 579                                         lttcomm_destroy_sock(newsock);
 580                                         free(relay_cmd);
 581                                         goto error;
 582                                 }
 583                                 relay_cmd->sock = newsock;
 584                                 /*
 585                                  * Lock free enqueue the request.
 586                                  */
 587                                 cds_wfq_enqueue(&relay_cmd_queue.queue, &relay_cmd->node);
 588
 589                                 /*
 590                                  * Wake the dispatch queue futex. Implicit memory
 591                                  * barrier with the exchange in cds_wfq_enqueue.
 592                                  */
 593                                 futex_nto1_wake(&relay_cmd_queue.futex);
 594                         }
 595                 }
 596         }
 597
 598 exit:
 599 error:
 600 error_poll_add:
 601         lttng_poll_clean(&events);
 602 error_create_poll:
 603         if (data_sock->fd >= 0) {
 604                 ret = data_sock->ops->close(data_sock);
 605                 if (ret) {
 606                         PERROR("close");
 607                 }
 608         }
 609         lttcomm_destroy_sock(data_sock);
 610 error_sock_relay:
 611         if (control_sock->fd >= 0) {
 612                 ret = control_sock->ops->close(control_sock);
 613                 if (ret) {
 614                         PERROR("close");
 615                 }
 616         }
 617         lttcomm_destroy_sock(control_sock);
 618 error_sock_control:
 619         if (err) {
 620                 DBG("Thread exited with error");
 621         }
 622         DBG("Relay listener thread cleanup complete");
 623         stop_threads();
 624         return NULL;
 625 }
 626
 627 /*
 628  * This thread manages the dispatching of the requests to worker threads
 629  */
 630 static
 631 void *relay_thread_dispatcher(void *data)
 632 {
 633         int ret;
 634         struct cds_wfq_node *node;
 635         struct relay_command *relay_cmd = NULL;
 636
 637         DBG("[thread] Relay dispatcher started");
 638
 639         while (!CMM_LOAD_SHARED(dispatch_thread_exit)) {
 640                 /* Atomically prepare the queue futex */
 641                 futex_nto1_prepare(&relay_cmd_queue.futex);
 642
 643                 do {
 644                         /* Dequeue commands */
 645                         node = cds_wfq_dequeue_blocking(&relay_cmd_queue.queue);
 646                         if (node == NULL) {
 647                                 DBG("Woken up but nothing in the relay command queue");
 648                                 /* Continue thread execution */
 649                                 break;
 650                         }
 651
 652                         relay_cmd = caa_container_of(node, struct relay_command, node);
 653                         DBG("Dispatching request waiting on sock %d", relay_cmd->sock->fd);
 654
 655                         /*
 656                          * Inform worker thread of the new request. This
 657                          * call is blocking so we can be assured that the data will be read
 658                          * at some point in time or wait to the end of the world :)
 659                          */
 660                         do {
 661                                 ret = write(relay_cmd_pipe[1], relay_cmd,
 662                                                 sizeof(struct relay_command));
 663                         } while (ret < 0 && errno == EINTR);
 664                         free(relay_cmd);
 665                         if (ret < 0) {
 666                                 PERROR("write cmd pipe");
 667                                 goto error;
 668                         }
 669                 } while (node != NULL);
 670
 671                 /* Futex wait on queue. Blocking call on futex() */
 672                 futex_nto1_wait(&relay_cmd_queue.futex);
 673         }
 674
 675 error:
 676         DBG("Dispatch thread dying");
 677         stop_threads();
 678         return NULL;
 679 }
 680
 681 /*
 682  * Return the realpath(3) of the path even if the last directory token does not
 683  * exist. For example, with /tmp/test1/test2, if test2/ does not exist but the
 684  * /tmp/test1 does, the real path is returned. In normal time, realpath(3)
 685  * fails if the end point directory does not exist.
 686  */
 687 static
 688 char *expand_full_path(const char *path)
 689 {
 690         const char *end_path = path;
 691         char *next, *cut_path, *expanded_path, *respath;
 692
 693         /* Find last token delimited by '/' */
 694         while ((next = strpbrk(end_path + 1, "/"))) {
 695                 end_path = next;
 696         }
 697
 698         /* Cut last token from original path */
 699         cut_path = strndup(path, end_path - path);
 700
 701         expanded_path = malloc(PATH_MAX);
 702         if (expanded_path == NULL) {
 703                 respath = NULL;
 704                 goto end;
 705         }
 706
 707         respath = realpath(cut_path, expanded_path);
 708         if (respath == NULL) {
 709                 switch (errno) {
 710                 case ENOENT:
 711                         ERR("%s: No such file or directory", cut_path);
 712                         break;
 713                 default:
 714                         PERROR("realpath");
 715                         break;
 716                 }
 717                 free(expanded_path);
 718         } else {
 719                 /* Add end part to expanded path */
 720                 strcat(respath, end_path);
 721         }
 722 end:
 723         free(cut_path);
 724         return respath;
 725 }
 726
 727
 728 /*
 729  *  config_get_default_path
 730  *
 731  *  Returns the HOME directory path. Caller MUST NOT free(3) the return pointer.
 732  */
 733 static
 734 char *config_get_default_path(void)
 735 {
 736         return getenv("HOME");
 737 }
 738
 739 /*
 740  * Create recursively directory using the FULL path.
 741  */
 742 static
 743 int mkdir_recursive(char *path, mode_t mode)
 744 {
 745         char *p, tmp[PATH_MAX];
 746         struct stat statbuf;
 747         size_t len;
 748         int ret;
 749
 750         ret = snprintf(tmp, sizeof(tmp), "%s", path);
 751         if (ret < 0) {
 752                 PERROR("snprintf mkdir");
 753                 goto error;
 754         }
 755
 756         len = ret;
 757         if (tmp[len - 1] == '/') {
 758                 tmp[len - 1] = 0;
 759         }
 760
 761         for (p = tmp + 1; *p; p++) {
 762                 if (*p == '/') {
 763                         *p = 0;
 764                         if (tmp[strlen(tmp) - 1] == '.' &&
 765                                         tmp[strlen(tmp) - 2] == '.' &&
 766                                         tmp[strlen(tmp) - 3] == '/') {
 767                                 ERR("Using '/../' is not permitted in the trace path (%s)",
 768                                                 tmp);
 769                                 ret = -1;
 770                                 goto error;
 771                         }
 772                         ret = stat(tmp, &statbuf);
 773                         if (ret < 0) {
 774                                 ret = mkdir(tmp, mode);
 775                                 if (ret < 0) {
 776                                         if (errno != EEXIST) {
 777                                                 PERROR("mkdir recursive");
 778                                                 ret = -errno;
 779                                                 goto error;
 780                                         }
 781                                 }
 782                         }
 783                         *p = '/';
 784                 }
 785         }
 786
 787         ret = mkdir(tmp, mode);
 788         if (ret < 0) {
 789                 if (errno != EEXIST) {
 790                         PERROR("mkdir recursive last piece");
 791                         ret = -errno;
 792                 } else {
 793                         ret = 0;
 794                 }
 795         }
 796
 797 error:
 798         return ret;
 799 }
 800
 801 static
 802 char *create_output_path_auto(char *path_name)
 803 {
 804         int ret;
 805         char *traces_path = NULL;
 806         char *alloc_path = NULL;
 807         char *default_path;
 808
 809         default_path = config_get_default_path();
 810         if (default_path == NULL) {
 811                 ERR("Home path not found.\n \
 812                                 Please specify an output path using -o, --output PATH");
 813                 goto exit;
 814         }
 815         alloc_path = strdup(default_path);
 816         if (alloc_path == NULL) {
 817                 PERROR("Path allocation");
 818                 goto exit;
 819         }
 820         ret = asprintf(&traces_path, "%s/" DEFAULT_TRACE_DIR_NAME
 821                         "/%s", alloc_path, path_name);
 822         if (ret < 0) {
 823                 PERROR("asprintf trace dir name");
 824                 goto exit;
 825         }
 826 exit:
 827         free(alloc_path);
 828         return traces_path;
 829 }
 830
 831 static
 832 char *create_output_path_noauto(char *path_name)
 833 {
 834         int ret;
 835         char *traces_path = NULL;
 836         char *full_path;
 837
 838         full_path = expand_full_path(opt_output_path);
 839         ret = asprintf(&traces_path, "%s/%s", full_path, path_name);
 840         if (ret < 0) {
 841                 PERROR("asprintf trace dir name");
 842                 goto exit;
 843         }
 844 exit:
 845         free(full_path);
 846         return traces_path;
 847 }
 848
 849 /*
 850  * create_output_path: create the output trace directory
 851  */
 852 static
 853 char *create_output_path(char *path_name)
 854 {
 855         if (opt_output_path == NULL) {
 856                 return create_output_path_auto(path_name);
 857         } else {
 858                 return create_output_path_noauto(path_name);
 859         }
 860 }
 861
 862 static
 863 void deferred_free_stream(struct rcu_head *head)
 864 {
 865         struct relay_stream *stream =
 866                 caa_container_of(head, struct relay_stream, rcu_node);
 867         free(stream);
 868 }
 869
 870 /*
 871  * relay_delete_session: Free all memory associated with a session and
 872  * close all the FDs
 873  */
 874 static
 875 void relay_delete_session(struct relay_command *cmd, struct lttng_ht *streams_ht)
 876 {
 877         struct lttng_ht_iter iter;
 878         struct lttng_ht_node_ulong *node;
 879         struct relay_stream *stream;
 880         int ret;
 881
 882         if (!cmd->session) {
 883                 return;
 884         }
 885
 886         DBG("Relay deleting session %" PRIu64, cmd->session->id);
 887
 888         lttcomm_destroy_sock(cmd->session->sock);
 889
 890         rcu_read_lock();
 891         cds_lfht_for_each_entry(streams_ht->ht, &iter.iter, node, node) {
 892                 node = lttng_ht_iter_get_node_ulong(&iter);
 893                 if (node) {
 894                         stream = caa_container_of(node,
 895                                         struct relay_stream, stream_n);
 896                         if (stream->session == cmd->session) {
 897                                 close(stream->fd);
 898                                 ret = lttng_ht_del(streams_ht, &iter);
 899                                 assert(!ret);
 900                                 call_rcu(&stream->rcu_node,
 901                                         deferred_free_stream);
 902                         }
 903                 }
 904         }
 905         rcu_read_unlock();
 906
 907         free(cmd->session);
 908 }
 909
 910 /*
 911  * relay_add_stream: allocate a new stream for a session
 912  */
 913 static
 914 int relay_add_stream(struct lttcomm_relayd_hdr *recv_hdr,
 915                 struct relay_command *cmd, struct lttng_ht *streams_ht)
 916 {
 917         struct relay_session *session = cmd->session;
 918         struct lttcomm_relayd_add_stream stream_info;
 919         struct relay_stream *stream = NULL;
 920         struct lttcomm_relayd_status_stream reply;
 921         char *path = NULL, *root_path = NULL;
 922         int ret, send_ret;
 923
 924         if (!session || session->version_check_done == 0) {
 925                 ERR("Trying to add a stream before version check");
 926                 ret = -1;
 927                 goto end_no_session;
 928         }
 929
 930         /* FIXME : use data_size for something ? */
 931         ret = cmd->sock->ops->recvmsg(cmd->sock, &stream_info,
 932                         sizeof(struct lttcomm_relayd_add_stream), MSG_WAITALL);
 933         if (ret < sizeof(struct lttcomm_relayd_add_stream)) {
 934                 ERR("Relay didn't receive valid add_stream struct size : %d", ret);
 935                 ret = -1;
 936                 goto end_no_session;
 937         }
 938         stream = zmalloc(sizeof(struct relay_stream));
 939         if (stream == NULL) {
 940                 PERROR("relay stream zmalloc");
 941                 ret = -1;
 942                 goto end_no_session;
 943         }
 944
 945         rcu_read_lock();
 946         stream->stream_handle = ++last_relay_stream_id;
 947         stream->prev_seq = -1ULL;
 948         stream->session = session;
 949
 950         root_path = create_output_path(stream_info.pathname);
 951         if (!root_path) {
 952                 ret = -1;
 953                 goto end;
 954         }
 955         ret = mkdir_recursive(root_path, S_IRWXU | S_IRWXG);
 956         if (ret < 0) {
 957                 ERR("relay creating output directory");
 958                 goto end;
 959         }
 960
 961         ret = asprintf(&path, "%s/%s", root_path, stream_info.channel_name);
 962         if (ret < 0) {
 963                 PERROR("asprintf stream path");
 964                 goto end;
 965         }
 966
 967         ret = open(path, O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG|S_IRWXO);
 968         if (ret < 0) {
 969                 PERROR("Relay creating trace file");
 970                 goto end;
 971         }
 972
 973         stream->fd = ret;
 974         DBG("Tracefile %s created", path);
 975
 976         lttng_ht_node_init_ulong(&stream->stream_n,
 977                         (unsigned long) stream->stream_handle);
 978         lttng_ht_add_unique_ulong(streams_ht,
 979                         &stream->stream_n);
 980
 981         DBG("Relay new stream added %s", stream_info.channel_name);
 982
 983 end:
 984         free(path);
 985         free(root_path);
 986         /* send the session id to the client or a negative return code on error */
 987         if (ret < 0) {
 988                 reply.ret_code = htobe32(LTTNG_ERR_UNK);
 989         } else {
 990                 reply.ret_code = htobe32(LTTNG_OK);
 991         }
 992         reply.handle = htobe64(stream->stream_handle);
 993         send_ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
 994                         sizeof(struct lttcomm_relayd_status_stream), 0);
 995         if (send_ret < 0) {
 996                 ERR("Relay sending stream id");
 997         }
 998         rcu_read_unlock();
 999
1000 end_no_session:
1001         return ret;
1002 }
1003
1004 /*
1005  * relay_close_stream: close a specific stream
1006  */
1007 static
1008 int relay_close_stream(struct lttcomm_relayd_hdr *recv_hdr,
1009                 struct relay_command *cmd, struct lttng_ht *streams_ht)
1010 {
1011         struct relay_session *session = cmd->session;
1012         struct lttcomm_relayd_close_stream stream_info;
1013         struct lttcomm_relayd_generic_reply reply;
1014         struct relay_stream *stream;
1015         int ret, send_ret;
1016         struct lttng_ht_node_ulong *node;
1017         struct lttng_ht_iter iter;
1018
1019         DBG("Close stream received");
1020
1021         if (!session || session->version_check_done == 0) {
1022                 ERR("Trying to close a stream before version check");
1023                 ret = -1;
1024                 goto end_no_session;
1025         }
1026
1027         ret = cmd->sock->ops->recvmsg(cmd->sock, &stream_info,
1028                         sizeof(struct lttcomm_relayd_close_stream), MSG_WAITALL);
1029         if (ret < sizeof(struct lttcomm_relayd_close_stream)) {
1030                 ERR("Relay didn't receive valid add_stream struct size : %d", ret);
1031                 ret = -1;
1032                 goto end_no_session;
1033         }
1034
1035         rcu_read_lock();
1036         lttng_ht_lookup(streams_ht,
1037                         (void *)((unsigned long) be64toh(stream_info.stream_id)),
1038                         &iter);
1039         node = lttng_ht_iter_get_node_ulong(&iter);
1040         if (node == NULL) {
1041                 DBG("Relay stream %" PRIu64 " not found", be64toh(stream_info.stream_id));
1042                 ret = -1;
1043                 goto end_unlock;
1044         }
1045
1046         stream = caa_container_of(node, struct relay_stream, stream_n);
1047         if (!stream) {
1048                 ret = -1;
1049                 goto end_unlock;
1050         }
1051
1052         stream->last_net_seq_num = be64toh(stream_info.last_net_seq_num);
1053         stream->close_flag = 1;
1054
1055         if (close_stream_check(stream)) {
1056                 int delret;
1057
1058                 close(stream->fd);
1059                 delret = lttng_ht_del(streams_ht, &iter);
1060                 assert(!delret);
1061                 call_rcu(&stream->rcu_node,
1062                                 deferred_free_stream);
1063                 DBG("Closed tracefile %d from close stream", stream->fd);
1064         }
1065
1066 end_unlock:
1067         rcu_read_unlock();
1068
1069         if (ret < 0) {
1070                 reply.ret_code = htobe32(LTTNG_ERR_UNK);
1071         } else {
1072                 reply.ret_code = htobe32(LTTNG_OK);
1073         }
1074         send_ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
1075                         sizeof(struct lttcomm_relayd_generic_reply), 0);
1076         if (send_ret < 0) {
1077                 ERR("Relay sending stream id");
1078         }
1079
1080 end_no_session:
1081         return ret;
1082 }
1083
1084 /*
1085  * relay_unknown_command: send -1 if received unknown command
1086  */
1087 static
1088 void relay_unknown_command(struct relay_command *cmd)
1089 {
1090         struct lttcomm_relayd_generic_reply reply;
1091         int ret;
1092
1093         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1094         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
1095                         sizeof(struct lttcomm_relayd_generic_reply), 0);
1096         if (ret < 0) {
1097                 ERR("Relay sending unknown command");
1098         }
1099 }
1100
1101 /*
1102  * relay_start: send an acknowledgment to the client to tell if we are
1103  * ready to receive data. We are ready if a session is established.
1104  */
1105 static
1106 int relay_start(struct lttcomm_relayd_hdr *recv_hdr,
1107                 struct relay_command *cmd)
1108 {
1109         int ret = htobe32(LTTNG_OK);
1110         struct lttcomm_relayd_generic_reply reply;
1111         struct relay_session *session = cmd->session;
1112
1113         if (!session) {
1114                 DBG("Trying to start the streaming without a session established");
1115                 ret = htobe32(LTTNG_ERR_UNK);
1116         }
1117
1118         reply.ret_code = ret;
1119         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
1120                         sizeof(struct lttcomm_relayd_generic_reply), 0);
1121         if (ret < 0) {
1122                 ERR("Relay sending start ack");
1123         }
1124
1125         return ret;
1126 }
1127
1128 /*
1129  * Get stream from stream id.
1130  * Need to be called with RCU read-side lock held.
1131  */
1132 static
1133 struct relay_stream *relay_stream_from_stream_id(uint64_t stream_id,
1134                 struct lttng_ht *streams_ht)
1135 {
1136         struct lttng_ht_node_ulong *node;
1137         struct lttng_ht_iter iter;
1138         struct relay_stream *ret;
1139
1140         lttng_ht_lookup(streams_ht,
1141                         (void *)((unsigned long) stream_id),
1142                         &iter);
1143         node = lttng_ht_iter_get_node_ulong(&iter);
1144         if (node == NULL) {
1145                 DBG("Relay stream %" PRIu64 " not found", stream_id);
1146                 ret = NULL;
1147                 goto end;
1148         }
1149
1150         ret = caa_container_of(node, struct relay_stream, stream_n);
1151
1152 end:
1153         return ret;
1154 }
1155
1156 /*
1157  * Append padding to the file pointed by the file descriptor fd.
1158  */
1159 static int write_padding_to_file(int fd, uint32_t size)
1160 {
1161         int ret = 0;
1162         char *zeros;
1163
1164         if (size == 0) {
1165                 goto end;
1166         }
1167
1168         zeros = zmalloc(size);
1169         if (zeros == NULL) {
1170                 PERROR("zmalloc zeros for padding");
1171                 ret = -1;
1172                 goto end;
1173         }
1174
1175         do {
1176                 ret = write(fd, zeros, size);
1177         } while (ret < 0 && errno == EINTR);
1178         if (ret < 0) {
1179                 PERROR("write padding to file");
1180         }
1181
1182         free(zeros);
1183
1184 end:
1185         return ret;
1186 }
1187
1188 /*
1189  * relay_recv_metadata: receive the metada for the session.
1190  */
1191 static
1192 int relay_recv_metadata(struct lttcomm_relayd_hdr *recv_hdr,
1193                 struct relay_command *cmd, struct lttng_ht *streams_ht)
1194 {
1195         int ret = htobe32(LTTNG_OK);
1196         struct relay_session *session = cmd->session;
1197         struct lttcomm_relayd_metadata_payload *metadata_struct;
1198         struct relay_stream *metadata_stream;
1199         uint64_t data_size, payload_size;
1200
1201         if (!session) {
1202                 ERR("Metadata sent before version check");
1203                 ret = -1;
1204                 goto end;
1205         }
1206
1207         data_size = payload_size = be64toh(recv_hdr->data_size);
1208         if (data_size < sizeof(struct lttcomm_relayd_metadata_payload)) {
1209                 ERR("Incorrect data size");
1210                 ret = -1;
1211                 goto end;
1212         }
1213         payload_size -= sizeof(struct lttcomm_relayd_metadata_payload);
1214
1215         if (data_buffer_size < data_size) {
1216                 /* In case the realloc fails, we can free the memory */
1217                 char *tmp_data_ptr = data_buffer;
1218                 data_buffer = realloc(data_buffer, data_size);
1219                 if (!data_buffer) {
1220                         ERR("Allocating data buffer");
1221                         free(tmp_data_ptr);
1222                         ret = -1;
1223                         goto end;
1224                 }
1225                 data_buffer_size = data_size;
1226         }
1227         memset(data_buffer, 0, data_size);
1228         DBG2("Relay receiving metadata, waiting for %" PRIu64 " bytes", data_size);
1229         ret = cmd->sock->ops->recvmsg(cmd->sock, data_buffer, data_size,
1230                         MSG_WAITALL);
1231         if (ret < 0 || ret != data_size) {
1232                 ret = -1;
1233                 ERR("Relay didn't receive the whole metadata");
1234                 goto end;
1235         }
1236         metadata_struct = (struct lttcomm_relayd_metadata_payload *) data_buffer;
1237
1238         rcu_read_lock();
1239         metadata_stream = relay_stream_from_stream_id(
1240                         be64toh(metadata_struct->stream_id), streams_ht);
1241         if (!metadata_stream) {
1242                 ret = -1;
1243                 goto end_unlock;
1244         }
1245
1246         do {
1247                 ret = write(metadata_stream->fd, metadata_struct->payload,
1248                                 payload_size);
1249         } while (ret < 0 && errno == EINTR);
1250         if (ret < payload_size) {
1251                 ERR("Relay error writing metadata on file");
1252                 ret = -1;
1253                 goto end_unlock;
1254         }
1255
1256         ret = write_padding_to_file(metadata_stream->fd,
1257                         be32toh(metadata_struct->padding_size));
1258         if (ret < 0) {
1259                 goto end_unlock;
1260         }
1261
1262         DBG2("Relay metadata written");
1263
1264 end_unlock:
1265         rcu_read_unlock();
1266 end:
1267         return ret;
1268 }
1269
1270 /*
1271  * relay_send_version: send relayd version number
1272  */
1273 static
1274 int relay_send_version(struct lttcomm_relayd_hdr *recv_hdr,
1275                 struct relay_command *cmd)
1276 {
1277         int ret;
1278         struct lttcomm_relayd_version reply;
1279         struct relay_session *session;
1280
1281         if (cmd->session == NULL) {
1282                 session = zmalloc(sizeof(struct relay_session));
1283                 if (session == NULL) {
1284                         PERROR("relay session zmalloc");
1285                         ret = -1;
1286                         goto end;
1287                 }
1288                 session->id = ++last_relay_session_id;
1289                 DBG("Created session %" PRIu64, session->id);
1290                 cmd->session = session;
1291         } else {
1292                 session = cmd->session;
1293         }
1294         session->version_check_done = 1;
1295
1296         ret = sscanf(VERSION, "%u.%u", &reply.major, &reply.minor);
1297         if (ret < 2) {
1298                 ERR("Error in scanning version");
1299                 ret = -1;
1300                 goto end;
1301         }
1302         reply.major = htobe32(reply.major);
1303         reply.minor = htobe32(reply.minor);
1304         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
1305                         sizeof(struct lttcomm_relayd_version), 0);
1306         if (ret < 0) {
1307                 ERR("Relay sending version");
1308         }
1309         DBG("Version check done (%u.%u)", be32toh(reply.major),
1310                         be32toh(reply.minor));
1311
1312 end:
1313         return ret;
1314 }
1315
1316 /*
1317  * Check for data pending for a given stream id from the session daemon.
1318  */
1319 static
1320 int relay_data_pending(struct lttcomm_relayd_hdr *recv_hdr,
1321                 struct relay_command *cmd, struct lttng_ht *streams_ht)
1322 {
1323         struct relay_session *session = cmd->session;
1324         struct lttcomm_relayd_data_pending msg;
1325         struct lttcomm_relayd_generic_reply reply;
1326         struct relay_stream *stream;
1327         int ret;
1328         struct lttng_ht_node_ulong *node;
1329         struct lttng_ht_iter iter;
1330         uint64_t last_net_seq_num, stream_id;
1331
1332         DBG("Data pending command received");
1333
1334         if (!session || session->version_check_done == 0) {
1335                 ERR("Trying to check for data before version check");
1336                 ret = -1;
1337                 goto end_no_session;
1338         }
1339
1340         ret = cmd->sock->ops->recvmsg(cmd->sock, &msg, sizeof(msg), MSG_WAITALL);
1341         if (ret < sizeof(msg)) {
1342                 ERR("Relay didn't receive valid data_pending struct size : %d", ret);
1343                 ret = -1;
1344                 goto end_no_session;
1345         }
1346
1347         stream_id = be64toh(msg.stream_id);
1348         last_net_seq_num = be64toh(msg.last_net_seq_num);
1349
1350         rcu_read_lock();
1351         lttng_ht_lookup(streams_ht, (void *)((unsigned long) stream_id), &iter);
1352         node = lttng_ht_iter_get_node_ulong(&iter);
1353         if (node == NULL) {
1354                 DBG("Relay stream %" PRIu64 " not found", stream_id);
1355                 ret = -1;
1356                 goto end_unlock;
1357         }
1358
1359         stream = caa_container_of(node, struct relay_stream, stream_n);
1360         assert(stream);
1361
1362         DBG("Data pending for stream id %" PRIu64 " prev_seq %" PRIu64
1363                         " and last_seq %" PRIu64, stream_id, stream->prev_seq,
1364                         last_net_seq_num);
1365
1366         /* Avoid wrapping issue */
1367         if (((int64_t) (stream->prev_seq - last_net_seq_num)) <= 0) {
1368                 /* Data has in fact been written and is NOT pending */
1369                 ret = 0;
1370         } else {
1371                 /* Data still being streamed thus pending */
1372                 ret = 1;
1373         }
1374
1375 end_unlock:
1376         rcu_read_unlock();
1377
1378         reply.ret_code = htobe32(ret);
1379         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
1380         if (ret < 0) {
1381                 ERR("Relay data pending ret code failed");
1382         }
1383
1384 end_no_session:
1385         return ret;
1386 }
1387
1388 /*
1389  * Wait for the control socket to reach a quiescent state.
1390  *
1391  * Note that for now, when receiving this command from the session daemon, this
1392  * means that every subsequent commands or data received on the control socket
1393  * has been handled. So, this is why we simply return OK here.
1394  */
1395 static
1396 int relay_quiescent_control(struct lttcomm_relayd_hdr *recv_hdr,
1397                 struct relay_command *cmd)
1398 {
1399         int ret;
1400         struct lttcomm_relayd_generic_reply reply;
1401
1402         DBG("Checking quiescent state on control socket");
1403
1404         reply.ret_code = htobe32(LTTNG_OK);
1405         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
1406         if (ret < 0) {
1407                 ERR("Relay data quiescent control ret code failed");
1408         }
1409
1410         return ret;
1411 }
1412
1413 /*
1414  * relay_process_control: Process the commands received on the control socket
1415  */
1416 static
1417 int relay_process_control(struct lttcomm_relayd_hdr *recv_hdr,
1418                 struct relay_command *cmd, struct lttng_ht *streams_ht)
1419 {
1420         int ret = 0;
1421
1422         switch (be32toh(recv_hdr->cmd)) {
1423                 /*
1424         case RELAYD_CREATE_SESSION:
1425                 ret = relay_create_session(recv_hdr, cmd);
1426                 break;
1427                 */
1428         case RELAYD_ADD_STREAM:
1429                 ret = relay_add_stream(recv_hdr, cmd, streams_ht);
1430                 break;
1431         case RELAYD_START_DATA:
1432                 ret = relay_start(recv_hdr, cmd);
1433                 break;
1434         case RELAYD_SEND_METADATA:
1435                 ret = relay_recv_metadata(recv_hdr, cmd, streams_ht);
1436                 break;
1437         case RELAYD_VERSION:
1438                 ret = relay_send_version(recv_hdr, cmd);
1439                 break;
1440         case RELAYD_CLOSE_STREAM:
1441                 ret = relay_close_stream(recv_hdr, cmd, streams_ht);
1442                 break;
1443         case RELAYD_DATA_PENDING:
1444                 ret = relay_data_pending(recv_hdr, cmd, streams_ht);
1445                 break;
1446         case RELAYD_QUIESCENT_CONTROL:
1447                 ret = relay_quiescent_control(recv_hdr, cmd);
1448                 break;
1449         case RELAYD_UPDATE_SYNC_INFO:
1450         default:
1451                 ERR("Received unknown command (%u)", be32toh(recv_hdr->cmd));
1452                 relay_unknown_command(cmd);
1453                 ret = -1;
1454                 goto end;
1455         }
1456
1457 end:
1458         return ret;
1459 }
1460
1461 /*
1462  * relay_process_data: Process the data received on the data socket
1463  */
1464 static
1465 int relay_process_data(struct relay_command *cmd, struct lttng_ht *streams_ht)
1466 {
1467         int ret = 0;
1468         struct relay_stream *stream;
1469         struct lttcomm_relayd_data_hdr data_hdr;
1470         uint64_t stream_id;
1471         uint64_t net_seq_num;
1472         uint32_t data_size;
1473
1474         ret = cmd->sock->ops->recvmsg(cmd->sock, &data_hdr,
1475                         sizeof(struct lttcomm_relayd_data_hdr), MSG_WAITALL);
1476         if (ret <= 0) {
1477                 ERR("Connections seems to be closed");
1478                 ret = -1;
1479                 goto end;
1480         }
1481
1482         stream_id = be64toh(data_hdr.stream_id);
1483
1484         rcu_read_lock();
1485         stream = relay_stream_from_stream_id(stream_id, streams_ht);
1486         if (!stream) {
1487                 ret = -1;
1488                 goto end_unlock;
1489         }
1490
1491         data_size = be32toh(data_hdr.data_size);
1492         if (data_buffer_size < data_size) {
1493                 char *tmp_data_ptr = data_buffer;
1494                 data_buffer = realloc(data_buffer, data_size);
1495                 if (!data_buffer) {
1496                         ERR("Allocating data buffer");
1497                         free(tmp_data_ptr);
1498                         ret = -1;
1499                         goto end_unlock;
1500                 }
1501                 data_buffer_size = data_size;
1502         }
1503         memset(data_buffer, 0, data_size);
1504
1505         net_seq_num = be64toh(data_hdr.net_seq_num);
1506
1507         DBG3("Receiving data of size %u for stream id %" PRIu64 " seqnum %" PRIu64,
1508                 data_size, stream_id, net_seq_num);
1509         ret = cmd->sock->ops->recvmsg(cmd->sock, data_buffer, data_size, MSG_WAITALL);
1510         if (ret <= 0) {
1511                 ret = -1;
1512                 goto end_unlock;
1513         }
1514
1515         do {
1516                 ret = write(stream->fd, data_buffer, data_size);
1517         } while (ret < 0 && errno == EINTR);
1518         if (ret < data_size) {
1519                 ERR("Relay error writing data to file");
1520                 ret = -1;
1521                 goto end_unlock;
1522         }
1523
1524         DBG2("Relay wrote %d bytes to tracefile for stream id %" PRIu64,
1525                         ret, stream->stream_handle);
1526
1527         ret = write_padding_to_file(stream->fd, be32toh(data_hdr.padding_size));
1528         if (ret < 0) {
1529                 goto end_unlock;
1530         }
1531
1532         stream->prev_seq = net_seq_num;
1533
1534         /* Check if we need to close the FD */
1535         if (close_stream_check(stream)) {
1536                 struct lttng_ht_iter iter;
1537
1538                 close(stream->fd);
1539                 iter.iter.node = &stream->stream_n.node;
1540                 ret = lttng_ht_del(streams_ht, &iter);
1541                 assert(!ret);
1542                 call_rcu(&stream->rcu_node,
1543                         deferred_free_stream);
1544                 DBG("Closed tracefile %d after recv data", stream->fd);
1545         }
1546
1547 end_unlock:
1548         rcu_read_unlock();
1549 end:
1550         return ret;
1551 }
1552
1553 static
1554 void relay_cleanup_poll_connection(struct lttng_poll_event *events, int pollfd)
1555 {
1556         int ret;
1557
1558         lttng_poll_del(events, pollfd);
1559
1560         ret = close(pollfd);
1561         if (ret < 0) {
1562                 ERR("Closing pollfd %d", pollfd);
1563         }
1564 }
1565
1566 static
1567 int relay_add_connection(int fd, struct lttng_poll_event *events,
1568                 struct lttng_ht *relay_connections_ht)
1569 {
1570         struct relay_command *relay_connection;
1571         int ret;
1572
1573         relay_connection = zmalloc(sizeof(struct relay_command));
1574         if (relay_connection == NULL) {
1575                 PERROR("Relay command zmalloc");
1576                 goto error;
1577         }
1578         ret = read(fd, relay_connection, sizeof(struct relay_command));
1579         if (ret < 0 || ret < sizeof(struct relay_command)) {
1580                 PERROR("read relay cmd pipe");
1581                 goto error_read;
1582         }
1583
1584         lttng_ht_node_init_ulong(&relay_connection->sock_n,
1585                         (unsigned long) relay_connection->sock->fd);
1586         rcu_read_lock();
1587         lttng_ht_add_unique_ulong(relay_connections_ht,
1588                         &relay_connection->sock_n);
1589         rcu_read_unlock();
1590         return lttng_poll_add(events,
1591                         relay_connection->sock->fd,
1592                         LPOLLIN | LPOLLRDHUP);
1593
1594 error_read:
1595         free(relay_connection);
1596 error:
1597         return -1;
1598 }
1599
1600 static
1601 void deferred_free_connection(struct rcu_head *head)
1602 {
1603         struct relay_command *relay_connection =
1604                 caa_container_of(head, struct relay_command, rcu_node);
1605
1606         lttcomm_destroy_sock(relay_connection->sock);
1607         free(relay_connection);
1608 }
1609
1610 static
1611 void relay_del_connection(struct lttng_ht *relay_connections_ht,
1612                 struct lttng_ht *streams_ht, struct lttng_ht_iter *iter,
1613                 struct relay_command *relay_connection)
1614 {
1615         int ret;
1616
1617         ret = lttng_ht_del(relay_connections_ht, iter);
1618         assert(!ret);
1619         if (relay_connection->type == RELAY_CONTROL) {
1620                 relay_delete_session(relay_connection, streams_ht);
1621         }
1622
1623         call_rcu(&relay_connection->rcu_node,
1624                 deferred_free_connection);
1625 }
1626
1627 /*
1628  * This thread does the actual work
1629  */
1630 static
1631 void *relay_thread_worker(void *data)
1632 {
1633         int i, ret, pollfd, err = -1;
1634         uint32_t revents, nb_fd;
1635         struct relay_command *relay_connection;
1636         struct lttng_poll_event events;
1637         struct lttng_ht *relay_connections_ht;
1638         struct lttng_ht_node_ulong *node;
1639         struct lttng_ht_iter iter;
1640         struct lttng_ht *streams_ht;
1641         struct lttcomm_relayd_hdr recv_hdr;
1642
1643         DBG("[thread] Relay worker started");
1644
1645         rcu_register_thread();
1646
1647         /* table of connections indexed on socket */
1648         relay_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1649         if (!relay_connections_ht) {
1650                 goto relay_connections_ht_error;
1651         }
1652
1653         /* tables of streams indexed by stream ID */
1654         streams_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1655         if (!streams_ht) {
1656                 goto streams_ht_error;
1657         }
1658
1659         ret = create_thread_poll_set(&events, 2);
1660         if (ret < 0) {
1661                 goto error_poll_create;
1662         }
1663
1664         ret = lttng_poll_add(&events, relay_cmd_pipe[0], LPOLLIN | LPOLLRDHUP);
1665         if (ret < 0) {
1666                 goto error;
1667         }
1668
1669         while (1) {
1670                 /* Zeroed the events structure */
1671                 lttng_poll_reset(&events);
1672
1673                 nb_fd = LTTNG_POLL_GETNB(&events);
1674
1675                 /* Infinite blocking call, waiting for transmission */
1676         restart:
1677                 DBG3("Relayd worker thread polling...");
1678                 ret = lttng_poll_wait(&events, -1);
1679                 if (ret < 0) {
1680                         /*
1681                          * Restart interrupted system call.
1682                          */
1683                         if (errno == EINTR) {
1684                                 goto restart;
1685                         }
1686                         goto error;
1687                 }
1688
1689                 for (i = 0; i < nb_fd; i++) {
1690                         /* Fetch once the poll data */
1691                         revents = LTTNG_POLL_GETEV(&events, i);
1692                         pollfd = LTTNG_POLL_GETFD(&events, i);
1693
1694                         /* Thread quit pipe has been closed. Killing thread. */
1695                         ret = check_thread_quit_pipe(pollfd, revents);
1696                         if (ret) {
1697                                 err = 0;
1698                                 goto exit;
1699                         }
1700
1701                         /* Inspect the relay cmd pipe for new connection */
1702                         if (pollfd == relay_cmd_pipe[0]) {
1703                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1704                                         ERR("Relay pipe error");
1705                                         goto error;
1706                                 } else if (revents & LPOLLIN) {
1707                                         DBG("Relay command received");
1708                                         ret = relay_add_connection(relay_cmd_pipe[0],
1709                                                         &events, relay_connections_ht);
1710                                         if (ret < 0) {
1711                                                 goto error;
1712                                         }
1713                                 }
1714                         } else if (revents > 0) {
1715                                 rcu_read_lock();
1716                                 lttng_ht_lookup(relay_connections_ht,
1717                                                 (void *)((unsigned long) pollfd),
1718                                                 &iter);
1719                                 node = lttng_ht_iter_get_node_ulong(&iter);
1720                                 if (node == NULL) {
1721                                         DBG2("Relay sock %d not found", pollfd);
1722                                         rcu_read_unlock();
1723                                         goto error;
1724                                 }
1725                                 relay_connection = caa_container_of(node,
1726                                                 struct relay_command, sock_n);
1727
1728                                 if (revents & (LPOLLERR)) {
1729                                         ERR("POLL ERROR");
1730                                         relay_cleanup_poll_connection(&events, pollfd);
1731                                         relay_del_connection(relay_connections_ht,
1732                                                         streams_ht, &iter,
1733                                                         relay_connection);
1734                                 } else if (revents & (LPOLLHUP | LPOLLRDHUP)) {
1735                                         DBG("Socket %d hung up", pollfd);
1736                                         relay_cleanup_poll_connection(&events, pollfd);
1737                                         relay_del_connection(relay_connections_ht,
1738                                                         streams_ht, &iter,
1739                                                         relay_connection);
1740                                 } else if (revents & LPOLLIN) {
1741                                         /* control socket */
1742                                         if (relay_connection->type == RELAY_CONTROL) {
1743                                                 ret = relay_connection->sock->ops->recvmsg(
1744                                                                 relay_connection->sock, &recv_hdr,
1745                                                                 sizeof(struct lttcomm_relayd_hdr), MSG_WAITALL);
1746                                                 /* connection closed */
1747                                                 if (ret <= 0) {
1748                                                         relay_cleanup_poll_connection(&events, pollfd);
1749                                                         relay_del_connection(relay_connections_ht,
1750                                                                         streams_ht, &iter,
1751                                                                         relay_connection);
1752                                                         DBG("Control connection closed with %d", pollfd);
1753                                                 } else {
1754                                                         if (relay_connection->session) {
1755                                                                 DBG2("Relay worker receiving data for session : %" PRIu64,
1756                                                                                 relay_connection->session->id);
1757                                                         }
1758                                                         ret = relay_process_control(&recv_hdr,
1759                                                                         relay_connection,
1760                                                                         streams_ht);
1761                                                         /*
1762                                                          * there was an error in processing a control
1763                                                          * command: clear the session
1764                                                          * */
1765                                                         if (ret < 0) {
1766                                                                 relay_cleanup_poll_connection(&events, pollfd);
1767                                                                 relay_del_connection(relay_connections_ht,
1768                                                                                 streams_ht, &iter,
1769                                                                                 relay_connection);
1770                                                                 DBG("Connection closed with %d", pollfd);
1771                                                         }
1772                                                 }
1773                                                 /* data socket */
1774                                         } else if (relay_connection->type == RELAY_DATA) {
1775                                                 ret = relay_process_data(relay_connection, streams_ht);
1776                                                 /* connection closed */
1777                                                 if (ret < 0) {
1778                                                         relay_cleanup_poll_connection(&events, pollfd);
1779                                                         relay_del_connection(relay_connections_ht,
1780                                                                         streams_ht, &iter,
1781                                                                         relay_connection);
1782                                                         DBG("Data connection closed with %d", pollfd);
1783                                                 }
1784                                         }
1785                                 }
1786                                 rcu_read_unlock();
1787                         }
1788                 }
1789         }
1790
1791 exit:
1792 error:
1793         lttng_poll_clean(&events);
1794
1795         /* empty the hash table and free the memory */
1796         rcu_read_lock();
1797         cds_lfht_for_each_entry(relay_connections_ht->ht, &iter.iter, node, node) {
1798                 node = lttng_ht_iter_get_node_ulong(&iter);
1799                 if (node) {
1800                         relay_connection = caa_container_of(node,
1801                                         struct relay_command, sock_n);
1802                         relay_del_connection(relay_connections_ht,
1803                                         streams_ht, &iter,
1804                                         relay_connection);
1805                 }
1806         }
1807         rcu_read_unlock();
1808 error_poll_create:
1809         lttng_ht_destroy(streams_ht);
1810 streams_ht_error:
1811         lttng_ht_destroy(relay_connections_ht);
1812 relay_connections_ht_error:
1813         /* Close relay cmd pipes */
1814         utils_close_pipe(relay_cmd_pipe);
1815         if (err) {
1816                 DBG("Thread exited with error");
1817         }
1818         DBG("Worker thread cleanup complete");
1819         free(data_buffer);
1820         stop_threads();
1821         rcu_unregister_thread();
1822         return NULL;
1823 }
1824
1825 /*
1826  * Create the relay command pipe to wake thread_manage_apps.
1827  * Closed in cleanup().
1828  */
1829 static int create_relay_cmd_pipe(void)
1830 {
1831         int ret;
1832
1833         ret = utils_create_pipe_cloexec(relay_cmd_pipe);
1834
1835         return ret;
1836 }
1837
1838 /*
1839  * main
1840  */
1841 int main(int argc, char **argv)
1842 {
1843         int ret = 0;
1844         void *status;
1845
1846         /* Create thread quit pipe */
1847         if ((ret = init_thread_quit_pipe()) < 0) {
1848                 goto error;
1849         }
1850
1851         /* Parse arguments */
1852         progname = argv[0];
1853         if ((ret = parse_args(argc, argv) < 0)) {
1854                 goto exit;
1855         }
1856
1857         if ((ret = set_signal_handler()) < 0) {
1858                 goto exit;
1859         }
1860
1861         /* Daemonize */
1862         if (opt_daemon) {
1863                 ret = daemon(0, 0);
1864                 if (ret < 0) {
1865                         PERROR("daemon");
1866                         goto exit;
1867                 }
1868         }
1869
1870         /* Check if daemon is UID = 0 */
1871         is_root = !getuid();
1872
1873         if (!is_root) {
1874                 if (control_uri->port < 1024 || data_uri->port < 1024) {
1875                         ERR("Need to be root to use ports < 1024");
1876                         ret = -1;
1877                         goto exit;
1878                 }
1879         }
1880
1881         /* Setup the thread apps communication pipe. */
1882         if ((ret = create_relay_cmd_pipe()) < 0) {
1883                 goto exit;
1884         }
1885
1886         /* Init relay command queue. */
1887         cds_wfq_init(&relay_cmd_queue.queue);
1888
1889         /* Set up max poll set size */
1890         lttng_poll_set_max_size();
1891
1892         /* Setup the dispatcher thread */
1893         ret = pthread_create(&dispatcher_thread, NULL,
1894                         relay_thread_dispatcher, (void *) NULL);
1895         if (ret != 0) {
1896                 PERROR("pthread_create dispatcher");
1897                 goto exit_dispatcher;
1898         }
1899
1900         /* Setup the worker thread */
1901         ret = pthread_create(&worker_thread, NULL,
1902                         relay_thread_worker, (void *) NULL);
1903         if (ret != 0) {
1904                 PERROR("pthread_create worker");
1905                 goto exit_worker;
1906         }
1907
1908         /* Setup the listener thread */
1909         ret = pthread_create(&listener_thread, NULL,
1910                         relay_thread_listener, (void *) NULL);
1911         if (ret != 0) {
1912                 PERROR("pthread_create listener");
1913                 goto exit_listener;
1914         }
1915
1916 exit_listener:
1917         ret = pthread_join(listener_thread, &status);
1918         if (ret != 0) {
1919                 PERROR("pthread_join");
1920                 goto error;     /* join error, exit without cleanup */
1921         }
1922
1923 exit_worker:
1924         ret = pthread_join(worker_thread, &status);
1925         if (ret != 0) {
1926                 PERROR("pthread_join");
1927                 goto error;     /* join error, exit without cleanup */
1928         }
1929
1930 exit_dispatcher:
1931         ret = pthread_join(dispatcher_thread, &status);
1932         if (ret != 0) {
1933                 PERROR("pthread_join");
1934                 goto error;     /* join error, exit without cleanup */
1935         }
1936
1937 exit:
1938         cleanup();
1939         if (!ret) {
1940                 exit(EXIT_SUCCESS);
1941         }
1942
1943 error:
1944         exit(EXIT_FAILURE);
1945 }