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         /* Close relay cmd pipes */
 243         utils_close_pipe(relay_cmd_pipe);
 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         free(cmd->session->sock);
 888
 889         rcu_read_lock();
 890         cds_lfht_for_each_entry(streams_ht->ht, &iter.iter, node, node) {
 891                 node = lttng_ht_iter_get_node_ulong(&iter);
 892                 if (node) {
 893                         stream = caa_container_of(node,
 894                                         struct relay_stream, stream_n);
 895                         if (stream->session == cmd->session) {
 896                                 close(stream->fd);
 897                                 ret = lttng_ht_del(streams_ht, &iter);
 898                                 assert(!ret);
 899                                 call_rcu(&stream->rcu_node,
 900                                         deferred_free_stream);
 901                         }
 902                 }
 903         }
 904         rcu_read_unlock();
 905 }
 906
 907 /*
 908  * relay_add_stream: allocate a new stream for a session
 909  */
 910 static
 911 int relay_add_stream(struct lttcomm_relayd_hdr *recv_hdr,
 912                 struct relay_command *cmd, struct lttng_ht *streams_ht)
 913 {
 914         struct relay_session *session = cmd->session;
 915         struct lttcomm_relayd_add_stream stream_info;
 916         struct relay_stream *stream = NULL;
 917         struct lttcomm_relayd_status_stream reply;
 918         char *path = NULL, *root_path = NULL;
 919         int ret, send_ret;
 920
 921         if (!session || session->version_check_done == 0) {
 922                 ERR("Trying to add a stream before version check");
 923                 ret = -1;
 924                 goto end_no_session;
 925         }
 926
 927         /* FIXME : use data_size for something ? */
 928         ret = cmd->sock->ops->recvmsg(cmd->sock, &stream_info,
 929                         sizeof(struct lttcomm_relayd_add_stream), MSG_WAITALL);
 930         if (ret < sizeof(struct lttcomm_relayd_add_stream)) {
 931                 ERR("Relay didn't receive valid add_stream struct size : %d", ret);
 932                 ret = -1;
 933                 goto end_no_session;
 934         }
 935         stream = zmalloc(sizeof(struct relay_stream));
 936         if (stream == NULL) {
 937                 PERROR("relay stream zmalloc");
 938                 ret = -1;
 939                 goto end_no_session;
 940         }
 941
 942         rcu_read_lock();
 943         stream->stream_handle = ++last_relay_stream_id;
 944         stream->prev_seq = -1ULL;
 945         stream->session = session;
 946
 947         root_path = create_output_path(stream_info.pathname);
 948         if (!root_path) {
 949                 ret = -1;
 950                 goto end;
 951         }
 952         ret = mkdir_recursive(root_path, S_IRWXU | S_IRWXG);
 953         if (ret < 0) {
 954                 ERR("relay creating output directory");
 955                 goto end;
 956         }
 957
 958         ret = asprintf(&path, "%s/%s", root_path, stream_info.channel_name);
 959         if (ret < 0) {
 960                 PERROR("asprintf stream path");
 961                 goto end;
 962         }
 963
 964         ret = open(path, O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG|S_IRWXO);
 965         if (ret < 0) {
 966                 PERROR("Relay creating trace file");
 967                 goto end;
 968         }
 969
 970         stream->fd = ret;
 971         DBG("Tracefile %s created", path);
 972
 973         lttng_ht_node_init_ulong(&stream->stream_n,
 974                         (unsigned long) stream->stream_handle);
 975         lttng_ht_add_unique_ulong(streams_ht,
 976                         &stream->stream_n);
 977
 978         DBG("Relay new stream added %s", stream_info.channel_name);
 979
 980 end:
 981         free(path);
 982         free(root_path);
 983         /* send the session id to the client or a negative return code on error */
 984         if (ret < 0) {
 985                 reply.ret_code = htobe32(LTTNG_ERR_UNK);
 986         } else {
 987                 reply.ret_code = htobe32(LTTNG_OK);
 988         }
 989         reply.handle = htobe64(stream->stream_handle);
 990         send_ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
 991                         sizeof(struct lttcomm_relayd_status_stream), 0);
 992         if (send_ret < 0) {
 993                 ERR("Relay sending stream id");
 994         }
 995         rcu_read_unlock();
 996
 997 end_no_session:
 998         return ret;
 999 }
1000
1001 /*
1002  * relay_close_stream: close a specific stream
1003  */
1004 static
1005 int relay_close_stream(struct lttcomm_relayd_hdr *recv_hdr,
1006                 struct relay_command *cmd, struct lttng_ht *streams_ht)
1007 {
1008         struct relay_session *session = cmd->session;
1009         struct lttcomm_relayd_close_stream stream_info;
1010         struct lttcomm_relayd_generic_reply reply;
1011         struct relay_stream *stream;
1012         int ret, send_ret;
1013         struct lttng_ht_node_ulong *node;
1014         struct lttng_ht_iter iter;
1015
1016         DBG("Close stream received");
1017
1018         if (!session || session->version_check_done == 0) {
1019                 ERR("Trying to close a stream before version check");
1020                 ret = -1;
1021                 goto end_no_session;
1022         }
1023
1024         ret = cmd->sock->ops->recvmsg(cmd->sock, &stream_info,
1025                         sizeof(struct lttcomm_relayd_close_stream), MSG_WAITALL);
1026         if (ret < sizeof(struct lttcomm_relayd_close_stream)) {
1027                 ERR("Relay didn't receive valid add_stream struct size : %d", ret);
1028                 ret = -1;
1029                 goto end_no_session;
1030         }
1031
1032         rcu_read_lock();
1033         lttng_ht_lookup(streams_ht,
1034                         (void *)((unsigned long) be64toh(stream_info.stream_id)),
1035                         &iter);
1036         node = lttng_ht_iter_get_node_ulong(&iter);
1037         if (node == NULL) {
1038                 DBG("Relay stream %" PRIu64 " not found", be64toh(stream_info.stream_id));
1039                 ret = -1;
1040                 goto end_unlock;
1041         }
1042
1043         stream = caa_container_of(node, struct relay_stream, stream_n);
1044         if (!stream) {
1045                 ret = -1;
1046                 goto end_unlock;
1047         }
1048
1049         stream->last_net_seq_num = be64toh(stream_info.last_net_seq_num);
1050         stream->close_flag = 1;
1051
1052         if (close_stream_check(stream)) {
1053                 int delret;
1054
1055                 close(stream->fd);
1056                 delret = lttng_ht_del(streams_ht, &iter);
1057                 assert(!delret);
1058                 call_rcu(&stream->rcu_node,
1059                                 deferred_free_stream);
1060                 DBG("Closed tracefile %d from close stream", stream->fd);
1061         }
1062
1063 end_unlock:
1064         rcu_read_unlock();
1065
1066         if (ret < 0) {
1067                 reply.ret_code = htobe32(LTTNG_ERR_UNK);
1068         } else {
1069                 reply.ret_code = htobe32(LTTNG_OK);
1070         }
1071         send_ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
1072                         sizeof(struct lttcomm_relayd_generic_reply), 0);
1073         if (send_ret < 0) {
1074                 ERR("Relay sending stream id");
1075         }
1076
1077 end_no_session:
1078         return ret;
1079 }
1080
1081 /*
1082  * relay_unknown_command: send -1 if received unknown command
1083  */
1084 static
1085 void relay_unknown_command(struct relay_command *cmd)
1086 {
1087         struct lttcomm_relayd_generic_reply reply;
1088         int ret;
1089
1090         reply.ret_code = htobe32(LTTNG_ERR_UNK);
1091         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
1092                         sizeof(struct lttcomm_relayd_generic_reply), 0);
1093         if (ret < 0) {
1094                 ERR("Relay sending unknown command");
1095         }
1096 }
1097
1098 /*
1099  * relay_start: send an acknowledgment to the client to tell if we are
1100  * ready to receive data. We are ready if a session is established.
1101  */
1102 static
1103 int relay_start(struct lttcomm_relayd_hdr *recv_hdr,
1104                 struct relay_command *cmd)
1105 {
1106         int ret = htobe32(LTTNG_OK);
1107         struct lttcomm_relayd_generic_reply reply;
1108         struct relay_session *session = cmd->session;
1109
1110         if (!session) {
1111                 DBG("Trying to start the streaming without a session established");
1112                 ret = htobe32(LTTNG_ERR_UNK);
1113         }
1114
1115         reply.ret_code = ret;
1116         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
1117                         sizeof(struct lttcomm_relayd_generic_reply), 0);
1118         if (ret < 0) {
1119                 ERR("Relay sending start ack");
1120         }
1121
1122         return ret;
1123 }
1124
1125 /*
1126  * Get stream from stream id.
1127  * Need to be called with RCU read-side lock held.
1128  */
1129 static
1130 struct relay_stream *relay_stream_from_stream_id(uint64_t stream_id,
1131                 struct lttng_ht *streams_ht)
1132 {
1133         struct lttng_ht_node_ulong *node;
1134         struct lttng_ht_iter iter;
1135         struct relay_stream *ret;
1136
1137         lttng_ht_lookup(streams_ht,
1138                         (void *)((unsigned long) stream_id),
1139                         &iter);
1140         node = lttng_ht_iter_get_node_ulong(&iter);
1141         if (node == NULL) {
1142                 DBG("Relay stream %" PRIu64 " not found", stream_id);
1143                 ret = NULL;
1144                 goto end;
1145         }
1146
1147         ret = caa_container_of(node, struct relay_stream, stream_n);
1148
1149 end:
1150         return ret;
1151 }
1152
1153 /*
1154  * Append padding to the file pointed by the file descriptor fd.
1155  */
1156 static int write_padding_to_file(int fd, uint32_t size)
1157 {
1158         int ret = 0;
1159         char *zeros;
1160
1161         if (size == 0) {
1162                 goto end;
1163         }
1164
1165         zeros = zmalloc(size);
1166         if (zeros == NULL) {
1167                 PERROR("zmalloc zeros for padding");
1168                 ret = -1;
1169                 goto end;
1170         }
1171
1172         do {
1173                 ret = write(fd, zeros, size);
1174         } while (ret < 0 && errno == EINTR);
1175         if (ret < 0) {
1176                 PERROR("write padding to file");
1177         }
1178
1179 end:
1180         return ret;
1181 }
1182
1183 /*
1184  * relay_recv_metadata: receive the metada for the session.
1185  */
1186 static
1187 int relay_recv_metadata(struct lttcomm_relayd_hdr *recv_hdr,
1188                 struct relay_command *cmd, struct lttng_ht *streams_ht)
1189 {
1190         int ret = htobe32(LTTNG_OK);
1191         struct relay_session *session = cmd->session;
1192         struct lttcomm_relayd_metadata_payload *metadata_struct;
1193         struct relay_stream *metadata_stream;
1194         uint64_t data_size, payload_size;
1195
1196         if (!session) {
1197                 ERR("Metadata sent before version check");
1198                 ret = -1;
1199                 goto end;
1200         }
1201
1202         data_size = payload_size = be64toh(recv_hdr->data_size);
1203         if (data_size < sizeof(struct lttcomm_relayd_metadata_payload)) {
1204                 ERR("Incorrect data size");
1205                 ret = -1;
1206                 goto end;
1207         }
1208         payload_size -= sizeof(struct lttcomm_relayd_metadata_payload);
1209
1210         if (data_buffer_size < data_size) {
1211                 /* In case the realloc fails, we can free the memory */
1212                 char *tmp_data_ptr = data_buffer;
1213                 data_buffer = realloc(data_buffer, data_size);
1214                 if (!data_buffer) {
1215                         ERR("Allocating data buffer");
1216                         free(tmp_data_ptr);
1217                         ret = -1;
1218                         goto end;
1219                 }
1220                 data_buffer_size = data_size;
1221         }
1222         memset(data_buffer, 0, data_size);
1223         DBG2("Relay receiving metadata, waiting for %" PRIu64 " bytes", data_size);
1224         ret = cmd->sock->ops->recvmsg(cmd->sock, data_buffer, data_size,
1225                         MSG_WAITALL);
1226         if (ret < 0 || ret != data_size) {
1227                 ret = -1;
1228                 ERR("Relay didn't receive the whole metadata");
1229                 goto end;
1230         }
1231         metadata_struct = (struct lttcomm_relayd_metadata_payload *) data_buffer;
1232
1233         rcu_read_lock();
1234         metadata_stream = relay_stream_from_stream_id(
1235                         be64toh(metadata_struct->stream_id), streams_ht);
1236         if (!metadata_stream) {
1237                 ret = -1;
1238                 goto end_unlock;
1239         }
1240
1241         do {
1242                 ret = write(metadata_stream->fd, metadata_struct->payload,
1243                                 payload_size);
1244         } while (ret < 0 && errno == EINTR);
1245         if (ret < payload_size) {
1246                 ERR("Relay error writing metadata on file");
1247                 ret = -1;
1248                 goto end_unlock;
1249         }
1250
1251         ret = write_padding_to_file(metadata_stream->fd,
1252                         be32toh(metadata_struct->padding_size));
1253         if (ret < 0) {
1254                 goto end_unlock;
1255         }
1256
1257         DBG2("Relay metadata written");
1258
1259 end_unlock:
1260         rcu_read_unlock();
1261 end:
1262         return ret;
1263 }
1264
1265 /*
1266  * relay_send_version: send relayd version number
1267  */
1268 static
1269 int relay_send_version(struct lttcomm_relayd_hdr *recv_hdr,
1270                 struct relay_command *cmd)
1271 {
1272         int ret;
1273         struct lttcomm_relayd_version reply;
1274         struct relay_session *session;
1275
1276         if (cmd->session == NULL) {
1277                 session = zmalloc(sizeof(struct relay_session));
1278                 if (session == NULL) {
1279                         PERROR("relay session zmalloc");
1280                         ret = -1;
1281                         goto end;
1282                 }
1283                 session->id = ++last_relay_session_id;
1284                 DBG("Created session %" PRIu64, session->id);
1285                 cmd->session = session;
1286         } else {
1287                 session = cmd->session;
1288         }
1289         session->version_check_done = 1;
1290
1291         ret = sscanf(VERSION, "%u.%u", &reply.major, &reply.minor);
1292         if (ret < 2) {
1293                 ERR("Error in scanning version");
1294                 ret = -1;
1295                 goto end;
1296         }
1297         reply.major = htobe32(reply.major);
1298         reply.minor = htobe32(reply.minor);
1299         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
1300                         sizeof(struct lttcomm_relayd_version), 0);
1301         if (ret < 0) {
1302                 ERR("Relay sending version");
1303         }
1304         DBG("Version check done (%u.%u)", be32toh(reply.major),
1305                         be32toh(reply.minor));
1306
1307 end:
1308         return ret;
1309 }
1310
1311 /*
1312  * Check for data availability for a given stream id from the session daemon.
1313  */
1314 static
1315 int relay_data_available(struct lttcomm_relayd_hdr *recv_hdr,
1316                 struct relay_command *cmd, struct lttng_ht *streams_ht)
1317 {
1318         struct relay_session *session = cmd->session;
1319         struct lttcomm_relayd_data_available msg;
1320         struct lttcomm_relayd_generic_reply reply;
1321         struct relay_stream *stream;
1322         int ret;
1323         struct lttng_ht_node_ulong *node;
1324         struct lttng_ht_iter iter;
1325         uint64_t last_net_seq_num, stream_id;
1326
1327         DBG("Data available command received");
1328
1329         if (!session || session->version_check_done == 0) {
1330                 ERR("Trying to check for data before version check");
1331                 ret = -1;
1332                 goto end_no_session;
1333         }
1334
1335         ret = cmd->sock->ops->recvmsg(cmd->sock, &msg, sizeof(msg), MSG_WAITALL);
1336         if (ret < sizeof(msg)) {
1337                 ERR("Relay didn't receive valid data_available struct size : %d", ret);
1338                 ret = -1;
1339                 goto end_no_session;
1340         }
1341
1342         stream_id = be64toh(msg.stream_id);
1343         last_net_seq_num = be64toh(msg.last_net_seq_num);
1344
1345         rcu_read_lock();
1346         lttng_ht_lookup(streams_ht, (void *)((unsigned long) stream_id), &iter);
1347         node = lttng_ht_iter_get_node_ulong(&iter);
1348         if (node == NULL) {
1349                 DBG("Relay stream %" PRIu64 " not found", stream_id);
1350                 ret = -1;
1351                 goto end_unlock;
1352         }
1353
1354         stream = caa_container_of(node, struct relay_stream, stream_n);
1355         assert(stream);
1356
1357         DBG("Data available for stream id %" PRIu64 " prev_seq %" PRIu64
1358                         " and last_seq %" PRIu64, stream_id, stream->prev_seq,
1359                         last_net_seq_num);
1360
1361         /* Avoid wrapping issue */
1362         if (((int64_t) (stream->prev_seq - last_net_seq_num)) <= 0) {
1363                 /* Data has in fact been written and is available */
1364                 ret = 1;
1365         } else {
1366                 /* Data still being streamed. */
1367                 ret = 0;
1368         }
1369
1370 end_unlock:
1371         rcu_read_unlock();
1372
1373         reply.ret_code = htobe32(ret);
1374         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
1375         if (ret < 0) {
1376                 ERR("Relay data available ret code failed");
1377         }
1378
1379 end_no_session:
1380         return ret;
1381 }
1382
1383 /*
1384  * Wait for the control socket to reach a quiescent state.
1385  *
1386  * Note that for now, when receiving this command from the session daemon, this
1387  * means that every subsequent commands or data received on the control socket
1388  * has been handled. So, this is why we simply return OK here.
1389  */
1390 static
1391 int relay_quiescent_control(struct lttcomm_relayd_hdr *recv_hdr,
1392                 struct relay_command *cmd)
1393 {
1394         int ret;
1395         struct lttcomm_relayd_generic_reply reply;
1396
1397         DBG("Checking quiescent state on control socket");
1398
1399         reply.ret_code = htobe32(LTTNG_OK);
1400         ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
1401         if (ret < 0) {
1402                 ERR("Relay data available ret code failed");
1403         }
1404
1405         return ret;
1406 }
1407
1408 /*
1409  * relay_process_control: Process the commands received on the control socket
1410  */
1411 static
1412 int relay_process_control(struct lttcomm_relayd_hdr *recv_hdr,
1413                 struct relay_command *cmd, struct lttng_ht *streams_ht)
1414 {
1415         int ret = 0;
1416
1417         switch (be32toh(recv_hdr->cmd)) {
1418                 /*
1419         case RELAYD_CREATE_SESSION:
1420                 ret = relay_create_session(recv_hdr, cmd);
1421                 break;
1422                 */
1423         case RELAYD_ADD_STREAM:
1424                 ret = relay_add_stream(recv_hdr, cmd, streams_ht);
1425                 break;
1426         case RELAYD_START_DATA:
1427                 ret = relay_start(recv_hdr, cmd);
1428                 break;
1429         case RELAYD_SEND_METADATA:
1430                 ret = relay_recv_metadata(recv_hdr, cmd, streams_ht);
1431                 break;
1432         case RELAYD_VERSION:
1433                 ret = relay_send_version(recv_hdr, cmd);
1434                 break;
1435         case RELAYD_CLOSE_STREAM:
1436                 ret = relay_close_stream(recv_hdr, cmd, streams_ht);
1437                 break;
1438         case RELAYD_DATA_AVAILABLE:
1439                 ret = relay_data_available(recv_hdr, cmd, streams_ht);
1440                 break;
1441         case RELAYD_QUIESCENT_CONTROL:
1442                 ret = relay_quiescent_control(recv_hdr, cmd);
1443                 break;
1444         case RELAYD_UPDATE_SYNC_INFO:
1445         default:
1446                 ERR("Received unknown command (%u)", be32toh(recv_hdr->cmd));
1447                 relay_unknown_command(cmd);
1448                 ret = -1;
1449                 goto end;
1450         }
1451
1452 end:
1453         return ret;
1454 }
1455
1456 /*
1457  * relay_process_data: Process the data received on the data socket
1458  */
1459 static
1460 int relay_process_data(struct relay_command *cmd, struct lttng_ht *streams_ht)
1461 {
1462         int ret = 0;
1463         struct relay_stream *stream;
1464         struct lttcomm_relayd_data_hdr data_hdr;
1465         uint64_t stream_id;
1466         uint64_t net_seq_num;
1467         uint32_t data_size;
1468
1469         ret = cmd->sock->ops->recvmsg(cmd->sock, &data_hdr,
1470                         sizeof(struct lttcomm_relayd_data_hdr), MSG_WAITALL);
1471         if (ret <= 0) {
1472                 ERR("Connections seems to be closed");
1473                 ret = -1;
1474                 goto end;
1475         }
1476
1477         stream_id = be64toh(data_hdr.stream_id);
1478
1479         rcu_read_lock();
1480         stream = relay_stream_from_stream_id(stream_id, streams_ht);
1481         if (!stream) {
1482                 ret = -1;
1483                 goto end_unlock;
1484         }
1485
1486         data_size = be32toh(data_hdr.data_size);
1487         if (data_buffer_size < data_size) {
1488                 char *tmp_data_ptr = data_buffer;
1489                 data_buffer = realloc(data_buffer, data_size);
1490                 if (!data_buffer) {
1491                         ERR("Allocating data buffer");
1492                         free(tmp_data_ptr);
1493                         ret = -1;
1494                         goto end_unlock;
1495                 }
1496                 data_buffer_size = data_size;
1497         }
1498         memset(data_buffer, 0, data_size);
1499
1500         net_seq_num = be64toh(data_hdr.net_seq_num);
1501
1502         DBG3("Receiving data of size %u for stream id %" PRIu64 " seqnum %" PRIu64,
1503                 data_size, stream_id, net_seq_num);
1504         ret = cmd->sock->ops->recvmsg(cmd->sock, data_buffer, data_size, MSG_WAITALL);
1505         if (ret <= 0) {
1506                 ret = -1;
1507                 goto end_unlock;
1508         }
1509
1510         do {
1511                 ret = write(stream->fd, data_buffer, data_size);
1512         } while (ret < 0 && errno == EINTR);
1513         if (ret < data_size) {
1514                 ERR("Relay error writing data to file");
1515                 ret = -1;
1516                 goto end_unlock;
1517         }
1518
1519         DBG2("Relay wrote %d bytes to tracefile for stream id %" PRIu64,
1520                         ret, stream->stream_handle);
1521
1522         ret = write_padding_to_file(stream->fd, be32toh(data_hdr.padding_size));
1523         if (ret < 0) {
1524                 goto end_unlock;
1525         }
1526
1527         stream->prev_seq = net_seq_num;
1528
1529         /* Check if we need to close the FD */
1530         if (close_stream_check(stream)) {
1531                 struct lttng_ht_iter iter;
1532
1533                 close(stream->fd);
1534                 iter.iter.node = &stream->stream_n.node;
1535                 ret = lttng_ht_del(streams_ht, &iter);
1536                 assert(!ret);
1537                 call_rcu(&stream->rcu_node,
1538                         deferred_free_stream);
1539                 DBG("Closed tracefile %d after recv data", stream->fd);
1540         }
1541
1542 end_unlock:
1543         rcu_read_unlock();
1544 end:
1545         return ret;
1546 }
1547
1548 static
1549 void relay_cleanup_poll_connection(struct lttng_poll_event *events, int pollfd)
1550 {
1551         int ret;
1552
1553         lttng_poll_del(events, pollfd);
1554
1555         ret = close(pollfd);
1556         if (ret < 0) {
1557                 ERR("Closing pollfd %d", pollfd);
1558         }
1559 }
1560
1561 static
1562 int relay_add_connection(int fd, struct lttng_poll_event *events,
1563                 struct lttng_ht *relay_connections_ht)
1564 {
1565         struct relay_command *relay_connection;
1566         int ret;
1567
1568         relay_connection = zmalloc(sizeof(struct relay_command));
1569         if (relay_connection == NULL) {
1570                 PERROR("Relay command zmalloc");
1571                 goto error;
1572         }
1573         ret = read(fd, relay_connection, sizeof(struct relay_command));
1574         if (ret < 0 || ret < sizeof(struct relay_command)) {
1575                 PERROR("read relay cmd pipe");
1576                 goto error_read;
1577         }
1578
1579         lttng_ht_node_init_ulong(&relay_connection->sock_n,
1580                         (unsigned long) relay_connection->sock->fd);
1581         rcu_read_lock();
1582         lttng_ht_add_unique_ulong(relay_connections_ht,
1583                         &relay_connection->sock_n);
1584         rcu_read_unlock();
1585         return lttng_poll_add(events,
1586                         relay_connection->sock->fd,
1587                         LPOLLIN | LPOLLRDHUP);
1588
1589 error_read:
1590         free(relay_connection);
1591 error:
1592         return -1;
1593 }
1594
1595 static
1596 void deferred_free_connection(struct rcu_head *head)
1597 {
1598         struct relay_command *relay_connection =
1599                 caa_container_of(head, struct relay_command, rcu_node);
1600         free(relay_connection);
1601 }
1602
1603 static
1604 void relay_del_connection(struct lttng_ht *relay_connections_ht,
1605                 struct lttng_ht *streams_ht, struct lttng_ht_iter *iter,
1606                 struct relay_command *relay_connection)
1607 {
1608         int ret;
1609
1610         ret = lttng_ht_del(relay_connections_ht, iter);
1611         assert(!ret);
1612         if (relay_connection->type == RELAY_CONTROL) {
1613                 relay_delete_session(relay_connection, streams_ht);
1614         }
1615         call_rcu(&relay_connection->rcu_node,
1616                 deferred_free_connection);
1617 }
1618
1619 /*
1620  * This thread does the actual work
1621  */
1622 static
1623 void *relay_thread_worker(void *data)
1624 {
1625         int i, ret, pollfd, err = -1;
1626         uint32_t revents, nb_fd;
1627         struct relay_command *relay_connection;
1628         struct lttng_poll_event events;
1629         struct lttng_ht *relay_connections_ht;
1630         struct lttng_ht_node_ulong *node;
1631         struct lttng_ht_iter iter;
1632         struct lttng_ht *streams_ht;
1633         struct lttcomm_relayd_hdr recv_hdr;
1634
1635         DBG("[thread] Relay worker started");
1636
1637         rcu_register_thread();
1638
1639         /* table of connections indexed on socket */
1640         relay_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1641         if (!relay_connections_ht) {
1642                 goto relay_connections_ht_error;
1643         }
1644
1645         /* tables of streams indexed by stream ID */
1646         streams_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1647         if (!streams_ht) {
1648                 goto streams_ht_error;
1649         }
1650
1651         ret = create_thread_poll_set(&events, 2);
1652         if (ret < 0) {
1653                 goto error_poll_create;
1654         }
1655
1656         ret = lttng_poll_add(&events, relay_cmd_pipe[0], LPOLLIN | LPOLLRDHUP);
1657         if (ret < 0) {
1658                 goto error;
1659         }
1660
1661         while (1) {
1662                 /* Zeroed the events structure */
1663                 lttng_poll_reset(&events);
1664
1665                 nb_fd = LTTNG_POLL_GETNB(&events);
1666
1667                 /* Infinite blocking call, waiting for transmission */
1668         restart:
1669                 DBG3("Relayd worker thread polling...");
1670                 ret = lttng_poll_wait(&events, -1);
1671                 if (ret < 0) {
1672                         /*
1673                          * Restart interrupted system call.
1674                          */
1675                         if (errno == EINTR) {
1676                                 goto restart;
1677                         }
1678                         goto error;
1679                 }
1680
1681                 for (i = 0; i < nb_fd; i++) {
1682                         /* Fetch once the poll data */
1683                         revents = LTTNG_POLL_GETEV(&events, i);
1684                         pollfd = LTTNG_POLL_GETFD(&events, i);
1685
1686                         /* Thread quit pipe has been closed. Killing thread. */
1687                         ret = check_thread_quit_pipe(pollfd, revents);
1688                         if (ret) {
1689                                 err = 0;
1690                                 goto exit;
1691                         }
1692
1693                         /* Inspect the relay cmd pipe for new connection */
1694                         if (pollfd == relay_cmd_pipe[0]) {
1695                                 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
1696                                         ERR("Relay pipe error");
1697                                         goto error;
1698                                 } else if (revents & LPOLLIN) {
1699                                         DBG("Relay command received");
1700                                         ret = relay_add_connection(relay_cmd_pipe[0],
1701                                                         &events, relay_connections_ht);
1702                                         if (ret < 0) {
1703                                                 goto error;
1704                                         }
1705                                 }
1706                         } else if (revents > 0) {
1707                                 rcu_read_lock();
1708                                 lttng_ht_lookup(relay_connections_ht,
1709                                                 (void *)((unsigned long) pollfd),
1710                                                 &iter);
1711                                 node = lttng_ht_iter_get_node_ulong(&iter);
1712                                 if (node == NULL) {
1713                                         DBG2("Relay sock %d not found", pollfd);
1714                                         rcu_read_unlock();
1715                                         goto error;
1716                                 }
1717                                 relay_connection = caa_container_of(node,
1718                                                 struct relay_command, sock_n);
1719
1720                                 if (revents & (LPOLLERR)) {
1721                                         ERR("POLL ERROR");
1722                                         relay_cleanup_poll_connection(&events, pollfd);
1723                                         relay_del_connection(relay_connections_ht,
1724                                                         streams_ht, &iter,
1725                                                         relay_connection);
1726                                 } else if (revents & (LPOLLHUP | LPOLLRDHUP)) {
1727                                         DBG("Socket %d hung up", pollfd);
1728                                         relay_cleanup_poll_connection(&events, pollfd);
1729                                         relay_del_connection(relay_connections_ht,
1730                                                         streams_ht, &iter,
1731                                                         relay_connection);
1732                                 } else if (revents & LPOLLIN) {
1733                                         /* control socket */
1734                                         if (relay_connection->type == RELAY_CONTROL) {
1735                                                 ret = relay_connection->sock->ops->recvmsg(
1736                                                                 relay_connection->sock, &recv_hdr,
1737                                                                 sizeof(struct lttcomm_relayd_hdr), MSG_WAITALL);
1738                                                 /* connection closed */
1739                                                 if (ret <= 0) {
1740                                                         relay_cleanup_poll_connection(&events, pollfd);
1741                                                         relay_del_connection(relay_connections_ht,
1742                                                                         streams_ht, &iter,
1743                                                                         relay_connection);
1744                                                         DBG("Control connection closed with %d", pollfd);
1745                                                 } else {
1746                                                         if (relay_connection->session) {
1747                                                                 DBG2("Relay worker receiving data for session : %" PRIu64,
1748                                                                                 relay_connection->session->id);
1749                                                         }
1750                                                         ret = relay_process_control(&recv_hdr,
1751                                                                         relay_connection,
1752                                                                         streams_ht);
1753                                                         /*
1754                                                          * there was an error in processing a control
1755                                                          * command: clear the session
1756                                                          * */
1757                                                         if (ret < 0) {
1758                                                                 relay_cleanup_poll_connection(&events, pollfd);
1759                                                                 relay_del_connection(relay_connections_ht,
1760                                                                                 streams_ht, &iter,
1761                                                                                 relay_connection);
1762                                                                 DBG("Connection closed with %d", pollfd);
1763                                                         }
1764                                                 }
1765                                                 /* data socket */
1766                                         } else if (relay_connection->type == RELAY_DATA) {
1767                                                 ret = relay_process_data(relay_connection, streams_ht);
1768                                                 /* connection closed */
1769                                                 if (ret < 0) {
1770                                                         relay_cleanup_poll_connection(&events, pollfd);
1771                                                         relay_del_connection(relay_connections_ht,
1772                                                                         streams_ht, &iter,
1773                                                                         relay_connection);
1774                                                         DBG("Data connection closed with %d", pollfd);
1775                                                 }
1776                                         }
1777                                 }
1778                                 rcu_read_unlock();
1779                         }
1780                 }
1781         }
1782
1783 exit:
1784 error:
1785         lttng_poll_clean(&events);
1786
1787         /* empty the hash table and free the memory */
1788         rcu_read_lock();
1789         cds_lfht_for_each_entry(relay_connections_ht->ht, &iter.iter, node, node) {
1790                 node = lttng_ht_iter_get_node_ulong(&iter);
1791                 if (node) {
1792                         relay_connection = caa_container_of(node,
1793                                         struct relay_command, sock_n);
1794                         relay_del_connection(relay_connections_ht,
1795                                         streams_ht, &iter,
1796                                         relay_connection);
1797                 }
1798         }
1799         rcu_read_unlock();
1800 error_poll_create:
1801         lttng_ht_destroy(streams_ht);
1802 streams_ht_error:
1803         lttng_ht_destroy(relay_connections_ht);
1804 relay_connections_ht_error:
1805         if (err) {
1806                 DBG("Thread exited with error");
1807         }
1808         DBG("Worker thread cleanup complete");
1809         free(data_buffer);
1810         stop_threads();
1811         rcu_unregister_thread();
1812         return NULL;
1813 }
1814
1815 /*
1816  * Create the relay command pipe to wake thread_manage_apps.
1817  * Closed in cleanup().
1818  */
1819 static int create_relay_cmd_pipe(void)
1820 {
1821         int ret;
1822
1823         ret = utils_create_pipe_cloexec(relay_cmd_pipe);
1824
1825         return ret;
1826 }
1827
1828 /*
1829  * main
1830  */
1831 int main(int argc, char **argv)
1832 {
1833         int ret = 0;
1834         void *status;
1835
1836         /* Create thread quit pipe */
1837         if ((ret = init_thread_quit_pipe()) < 0) {
1838                 goto error;
1839         }
1840
1841         /* Parse arguments */
1842         progname = argv[0];
1843         if ((ret = parse_args(argc, argv) < 0)) {
1844                 goto exit;
1845         }
1846
1847         if ((ret = set_signal_handler()) < 0) {
1848                 goto exit;
1849         }
1850
1851         /* Daemonize */
1852         if (opt_daemon) {
1853                 ret = daemon(0, 0);
1854                 if (ret < 0) {
1855                         PERROR("daemon");
1856                         goto exit;
1857                 }
1858         }
1859
1860         /* Check if daemon is UID = 0 */
1861         is_root = !getuid();
1862
1863         if (!is_root) {
1864                 if (control_uri->port < 1024 || data_uri->port < 1024) {
1865                         ERR("Need to be root to use ports < 1024");
1866                         ret = -1;
1867                         goto exit;
1868                 }
1869         }
1870
1871         /* Setup the thread apps communication pipe. */
1872         if ((ret = create_relay_cmd_pipe()) < 0) {
1873                 goto exit;
1874         }
1875
1876         /* Init relay command queue. */
1877         cds_wfq_init(&relay_cmd_queue.queue);
1878
1879         /* Set up max poll set size */
1880         lttng_poll_set_max_size();
1881
1882         /* Setup the dispatcher thread */
1883         ret = pthread_create(&dispatcher_thread, NULL,
1884                         relay_thread_dispatcher, (void *) NULL);
1885         if (ret != 0) {
1886                 PERROR("pthread_create dispatcher");
1887                 goto exit_dispatcher;
1888         }
1889
1890         /* Setup the worker thread */
1891         ret = pthread_create(&worker_thread, NULL,
1892                         relay_thread_worker, (void *) NULL);
1893         if (ret != 0) {
1894                 PERROR("pthread_create worker");
1895                 goto exit_worker;
1896         }
1897
1898         /* Setup the listener thread */
1899         ret = pthread_create(&listener_thread, NULL,
1900                         relay_thread_listener, (void *) NULL);
1901         if (ret != 0) {
1902                 PERROR("pthread_create listener");
1903                 goto exit_listener;
1904         }
1905
1906 exit_listener:
1907         ret = pthread_join(listener_thread, &status);
1908         if (ret != 0) {
1909                 PERROR("pthread_join");
1910                 goto error;     /* join error, exit without cleanup */
1911         }
1912
1913 exit_worker:
1914         ret = pthread_join(worker_thread, &status);
1915         if (ret != 0) {
1916                 PERROR("pthread_join");
1917                 goto error;     /* join error, exit without cleanup */
1918         }
1919
1920 exit_dispatcher:
1921         ret = pthread_join(dispatcher_thread, &status);
1922         if (ret != 0) {
1923                 PERROR("pthread_join");
1924                 goto error;     /* join error, exit without cleanup */
1925         }
1926
1927 exit:
1928         cleanup();
1929         if (!ret) {
1930                 exit(EXIT_SUCCESS);
1931         }
1932
1933 error:
1934         exit(EXIT_FAILURE);
1935 }