kconsumerd/kconsumerd.c

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  18  */
  19
  20 #define _GNU_SOURCE
  21 #include <fcntl.h>
  22 #include <getopt.h>
  23 #include <grp.h>
  24 #include <limits.h>
  25 #include <pthread.h>
  26 #include <signal.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <sys/ipc.h>
  31 #include <sys/shm.h>
  32 #include <sys/socket.h>
  33 #include <sys/stat.h>
  34 #include <sys/types.h>
  35 #include <urcu/list.h>
  36 #include <poll.h>
  37 #include <unistd.h>
  38
  39 #include "lttngerr.h"
  40 #include "libkernelctl.h"
  41 #include "liblttsessiondcomm.h"
  42 #include "kconsumerd.h"
  43
  44 /* Init the list of FDs */
  45 static struct ltt_kconsumerd_fd_list kconsumerd_fd_list = {
  46         .head = CDS_LIST_HEAD_INIT(kconsumerd_fd_list.head),
  47 };
  48
  49 /* Number of element for the list below. */
  50 static unsigned int fds_count;
  51
  52 /* If the local array of FDs needs update in the poll function */
  53 static unsigned int update_fd_array = 1;
  54
  55 /* lock the fd array and structures */
  56 static pthread_mutex_t kconsumerd_lock_fds;
  57
  58 /* the two threads (receive fd and poll) */
  59 static pthread_t threads[2];
  60
  61 /* communication with splice */
  62 static int thread_pipe[2];
  63
  64 /* socket to communicate errors with sessiond */
  65 static int error_socket = -1;
  66
  67 /* Argument variables */
  68 int opt_quiet;
  69 int opt_verbose;
  70 static int opt_daemon;
  71 static const char *progname;
  72 static char command_sock_path[PATH_MAX]; /* Global command socket path */
  73 static char error_sock_path[PATH_MAX]; /* Global error path */
  74
  75 /*
  76  * del_fd
  77  *
  78  * Remove a fd from the global list protected by a mutex
  79  */
  80 static void del_fd(struct ltt_kconsumerd_fd *lcf)
  81 {
  82         pthread_mutex_lock(&kconsumerd_lock_fds);
  83         cds_list_del(&lcf->list);
  84         if (fds_count > 0) {
  85                 fds_count--;
  86                 DBG("Removed ltt_kconsumerd_fd");
  87                 if (lcf != NULL) {
  88                         close(lcf->out_fd);
  89                         close(lcf->consumerd_fd);
  90                         free(lcf);
  91                         lcf = NULL;
  92                 }
  93         }
  94         pthread_mutex_unlock(&kconsumerd_lock_fds);
  95 }
  96
  97 /*
  98  *  cleanup
  99  *
 100  *  Cleanup the daemon's socket on exit
 101  */
 102 static void cleanup()
 103 {
 104         struct ltt_kconsumerd_fd *iter;
 105
 106
 107         /* remove the socket file */
 108         unlink(command_sock_path);
 109
 110         /* unblock the threads */
 111         WARN("Terminating the threads before exiting");
 112         pthread_cancel(threads[0]);
 113         pthread_cancel(threads[1]);
 114
 115         /* close all outfd */
 116         cds_list_for_each_entry(iter, &kconsumerd_fd_list.head, list) {
 117                 del_fd(iter);
 118         }
 119 }
 120
 121 /* send_error
 122  *
 123  * send return code to ltt-sessiond
 124  */
 125 static int send_error(enum lttcomm_return_code cmd)
 126 {
 127         if (error_socket > 0) {
 128                 return lttcomm_send_unix_sock(error_socket, &cmd,
 129                                 sizeof(enum lttcomm_sessiond_command));
 130         } else {
 131                 return 0;
 132         }
 133 }
 134
 135 /*
 136  * add_fd
 137  *
 138  * Add a fd to the global list protected by a mutex
 139  */
 140 static int add_fd(struct lttcomm_kconsumerd_msg *buf, int consumerd_fd)
 141 {
 142         struct ltt_kconsumerd_fd *tmp_fd;
 143         int ret;
 144
 145         tmp_fd = malloc(sizeof(struct ltt_kconsumerd_fd));
 146         tmp_fd->sessiond_fd = buf->fd;
 147         tmp_fd->consumerd_fd = consumerd_fd;
 148         tmp_fd->state = buf->state;
 149         tmp_fd->max_sb_size = buf->max_sb_size;
 150         strncpy(tmp_fd->path_name, buf->path_name, PATH_MAX);
 151
 152         /* Opening the tracefile in write mode */
 153         DBG("Opening %s for writing", tmp_fd->path_name);
 154         ret = open(tmp_fd->path_name,
 155                         O_WRONLY|O_CREAT, S_IRWXU|S_IRWXG|S_IRWXO);
 156         if (ret < 0) {
 157                 ERR("Opening %s", tmp_fd->path_name);
 158                 perror("open");
 159                 goto end;
 160         }
 161         tmp_fd->out_fd = ret;
 162         tmp_fd->out_fd_offset = 0;
 163
 164         DBG("Adding %s (%d, %d, %d)", tmp_fd->path_name,
 165                         tmp_fd->sessiond_fd, tmp_fd->consumerd_fd, tmp_fd->out_fd);
 166
 167         pthread_mutex_lock(&kconsumerd_lock_fds);
 168         cds_list_add(&tmp_fd->list, &kconsumerd_fd_list.head);
 169         fds_count++;
 170         pthread_mutex_unlock(&kconsumerd_lock_fds);
 171
 172 end:
 173         return ret;
 174 }
 175
 176
 177 /*
 178  *  sighandler
 179  *
 180  *  Signal handler for the daemon
 181  */
 182 static void sighandler(int sig)
 183 {
 184         cleanup();
 185
 186         return;
 187 }
 188
 189 /*
 190  *  set_signal_handler
 191  *
 192  *  Setup signal handler for :
 193  *      SIGINT, SIGTERM, SIGPIPE
 194  */
 195 static int set_signal_handler(void)
 196 {
 197         int ret = 0;
 198         struct sigaction sa;
 199         sigset_t sigset;
 200
 201         if ((ret = sigemptyset(&sigset)) < 0) {
 202                 perror("sigemptyset");
 203                 return ret;
 204         }
 205
 206         sa.sa_handler = sighandler;
 207         sa.sa_mask = sigset;
 208         sa.sa_flags = 0;
 209         if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
 210                 perror("sigaction");
 211                 return ret;
 212         }
 213
 214         if ((ret = sigaction(SIGINT, &sa, NULL)) < 0) {
 215                 perror("sigaction");
 216                 return ret;
 217         }
 218
 219         if ((ret = sigaction(SIGPIPE, &sa, NULL)) < 0) {
 220                 perror("sigaction");
 221                 return ret;
 222         }
 223
 224         return ret;
 225 }
 226
 227 /*
 228  * on_read_subbuffer
 229  *
 230  * Splice the data from the ring buffer to the tracefile.
 231  * Returns the number of bytes spliced
 232  */
 233 static int on_read_subbuffer(struct ltt_kconsumerd_fd *kconsumerd_fd,
 234                 unsigned long len)
 235 {
 236         long ret = 0;
 237         loff_t offset = 0;
 238         off_t orig_offset = kconsumerd_fd->out_fd_offset;
 239         int fd = kconsumerd_fd->consumerd_fd;
 240         int outfd = kconsumerd_fd->out_fd;
 241
 242         while (len > 0) {
 243                 DBG("splice chan to pipe offset %lu (fd : %d)",
 244                                 (unsigned long)offset, fd);
 245                 ret = splice(fd, &offset, thread_pipe[1], NULL, len,
 246                                 SPLICE_F_MOVE | SPLICE_F_MORE);
 247                 DBG("splice chan to pipe ret %ld", ret);
 248                 if (ret < 0) {
 249                         ret = errno;
 250                         perror("Error in relay splice");
 251                         goto splice_error;
 252                 }
 253
 254                 ret = splice(thread_pipe[0], NULL, outfd, NULL, ret,
 255                                 SPLICE_F_MOVE | SPLICE_F_MORE);
 256                 DBG("splice pipe to file %ld", ret);
 257                 if (ret < 0) {
 258                         ret = errno;
 259                         perror("Error in file splice");
 260                         goto splice_error;
 261                 }
 262                 if (ret >= len) {
 263                         len = 0;
 264                 }
 265                 /* This won't block, but will start writeout asynchronously */
 266                 sync_file_range(outfd, kconsumerd_fd->out_fd_offset, ret,
 267                                 SYNC_FILE_RANGE_WRITE);
 268                 kconsumerd_fd->out_fd_offset += ret;
 269         }
 270
 271         /*
 272          * This does a blocking write-and-wait on any page that belongs to the
 273          * subbuffer prior to the one we just wrote.
 274          * Don't care about error values, as these are just hints and ways to
 275          * limit the amount of page cache used.
 276          */
 277         if (orig_offset >= kconsumerd_fd->max_sb_size) {
 278                 sync_file_range(outfd, orig_offset - kconsumerd_fd->max_sb_size,
 279                                 kconsumerd_fd->max_sb_size,
 280                                 SYNC_FILE_RANGE_WAIT_BEFORE
 281                                 | SYNC_FILE_RANGE_WRITE
 282                                 | SYNC_FILE_RANGE_WAIT_AFTER);
 283                 /*
 284                  * Give hints to the kernel about how we access the file:
 285                  * POSIX_FADV_DONTNEED : we won't re-access data in a near
 286                  * future after we write it.
 287                  * We need to call fadvise again after the file grows because
 288                  * the kernel does not seem to apply fadvise to non-existing
 289                  * parts of the file.
 290                  * Call fadvise _after_ having waited for the page writeback to
 291                  * complete because the dirty page writeback semantic is not
 292                  * well defined. So it can be expected to lead to lower
 293                  * throughput in streaming.
 294                  */
 295                 posix_fadvise(outfd, orig_offset - kconsumerd_fd->max_sb_size,
 296                                 kconsumerd_fd->max_sb_size, POSIX_FADV_DONTNEED);
 297         }
 298         goto end;
 299
 300 splice_error:
 301         /* send the appropriate error description to sessiond */
 302         switch(ret) {
 303                 case EBADF:
 304                         send_error(KCONSUMERD_SPLICE_EBADF);
 305                         break;
 306                 case EINVAL:
 307                         send_error(KCONSUMERD_SPLICE_EINVAL);
 308                         break;
 309                 case ENOMEM:
 310                         send_error(KCONSUMERD_SPLICE_ENOMEM);
 311                         break;
 312                 case ESPIPE:
 313                         send_error(KCONSUMERD_SPLICE_ESPIPE);
 314                         break;
 315         }
 316
 317 end:
 318         return ret;
 319 }
 320
 321 /*
 322  * read_subbuffer
 323  *
 324  * Consume data on a file descriptor and write it on a trace file
 325  */
 326 static int read_subbuffer(struct ltt_kconsumerd_fd *kconsumerd_fd)
 327 {
 328         unsigned long len;
 329         int err;
 330         long ret = 0;
 331         int infd = kconsumerd_fd->consumerd_fd;
 332
 333         DBG("In read_subbuffer");
 334         /* Get the next subbuffer */
 335         err = kernctl_get_next_subbuf(infd);
 336         if (err != 0) {
 337                 ret = errno;
 338                 perror("Reserving sub buffer failed (everything is normal, "
 339                                 "it is due to concurrency)");
 340                 goto end;
 341         }
 342
 343         /* read the whole subbuffer */
 344         err = kernctl_get_padded_subbuf_size(infd, &len);
 345         if (err != 0) {
 346                 ret = errno;
 347                 perror("Getting sub-buffer len failed.");
 348                 goto end;
 349         }
 350
 351         /* splice the subbuffer to the tracefile */
 352         ret = on_read_subbuffer(kconsumerd_fd, len);
 353         if (ret < 0) {
 354                 /*
 355                  * display the error but continue processing to try
 356                  * to release the subbuffer
 357                  */
 358                 ERR("Error splicing to tracefile");
 359         }
 360
 361         err = kernctl_put_next_subbuf(infd);
 362         if (err != 0) {
 363                 ret = errno;
 364                 if (errno == EFAULT) {
 365                         perror("Error in unreserving sub buffer\n");
 366                 } else if (errno == EIO) {
 367                         /* Should never happen with newer LTTng versions */
 368                         perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
 369                 }
 370                 goto end;
 371         }
 372
 373 end:
 374         return ret;
 375 }
 376
 377 /*
 378  * change_fd_state
 379  *
 380  * Update a fd according to what we just received
 381  */
 382 static void change_fd_state(int sessiond_fd,
 383                 enum lttcomm_kconsumerd_fd_state state)
 384 {
 385         struct ltt_kconsumerd_fd *iter;
 386         cds_list_for_each_entry(iter, &kconsumerd_fd_list.head, list) {
 387                 if (iter->sessiond_fd == sessiond_fd) {
 388                         iter->state = state;
 389                         break;
 390                 }
 391         }
 392 }
 393
 394 /*
 395  * consumerd_recv_fd
 396  *
 397  * Receives an array of file descriptors and the associated
 398  * structures describing each fd (path name).
 399  * Returns the size of received data
 400  */
 401 static int consumerd_recv_fd(int sfd, int size,
 402                 enum lttcomm_consumerd_command cmd_type)
 403 {
 404         struct msghdr msg;
 405         struct iovec iov[1];
 406         int ret, i;
 407         struct cmsghdr *cmsg;
 408         int nb_fd;
 409         char tmp[CMSG_SPACE(size)];
 410         struct lttcomm_kconsumerd_msg *buf;
 411         /* the number of fds we are about to receive */
 412         nb_fd = size/sizeof(struct lttcomm_kconsumerd_msg);
 413
 414         buf = malloc(size);
 415
 416         memset(&msg, 0, sizeof(msg));
 417
 418         /* Prepare to receive the structures */
 419         iov[0].iov_base = buf;
 420         iov[0].iov_len = size;
 421         msg.msg_iov = iov;
 422         msg.msg_iovlen = 1;
 423
 424         msg.msg_control = tmp;
 425         msg.msg_controllen = sizeof(tmp);
 426
 427         DBG("Waiting to receive fds");
 428         if ((ret = recvmsg(sfd, &msg, 0)) < 0) {
 429                 perror("recvmsg");
 430         }
 431         if (ret != size) {
 432                 ERR("Received only %d, expected %d", ret, size);
 433                 send_error(KCONSUMERD_ERROR_RECV_FD);
 434                 goto end;
 435         }
 436
 437         cmsg = CMSG_FIRSTHDR(&msg);
 438         if (!cmsg) {
 439                 ERR("Invalid control message header");
 440                 ret = -1;
 441                 send_error(KCONSUMERD_ERROR_RECV_FD);
 442                 goto end;
 443         }
 444
 445         /* if we received fds */
 446         if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
 447                 DBG("Receive : expecting %d fds", nb_fd);
 448                 for (i = 0; i < nb_fd; i++) {
 449                         switch (cmd_type) {
 450                                 case LTTCOMM_ADD_STREAM:
 451                                         DBG("add_fd %s (%d)", buf[i].path_name, ((int *)CMSG_DATA(cmsg))[i]);
 452                                         ret = add_fd(&buf[i], ((int *)CMSG_DATA(cmsg))[i]);
 453                                         if (ret < 0) {
 454                                                 send_error(KCONSUMERD_OUTFD_ERROR);
 455                                                 goto end;
 456                                         }
 457                                         break;
 458                                 case LTTCOMM_UPDATE_STREAM:
 459                                         change_fd_state(buf[i].fd, buf[i].state);
 460                                         break;
 461                                 default:
 462                                         break;
 463                         }
 464                 }
 465                 /* flag to tell the polling thread to update its fd array */
 466                 update_fd_array = 1;
 467                 send_error(KCONSUMERD_SUCCESS_RECV_FD);
 468         } else {
 469                 ERR("Didn't received any fd");
 470                 send_error(KCONSUMERD_ERROR_RECV_FD);
 471                 ret = -1;
 472                 goto end;
 473         }
 474
 475 end:
 476         if (buf != NULL) {
 477                 free(buf);
 478                 buf = NULL;
 479         }
 480         return ret;
 481 }
 482
 483 /*
 484  *  thread_receive_fds
 485  *
 486  *  This thread listens on the consumerd socket and
 487  *  receives the file descriptors from ltt-sessiond
 488  */
 489 static void *thread_receive_fds(void *data)
 490 {
 491         int sock, client_socket, ret;
 492         struct lttcomm_kconsumerd_header tmp;
 493
 494         DBG("Creating command socket %s", command_sock_path);
 495         unlink(command_sock_path);
 496         client_socket = lttcomm_create_unix_sock(command_sock_path);
 497         if (client_socket < 0) {
 498                 ERR("Cannot create command socket");
 499                 goto error;
 500         }
 501
 502         ret = lttcomm_listen_unix_sock(client_socket);
 503         if (ret < 0) {
 504                 goto error;
 505         }
 506
 507         DBG("Sending ready command to ltt-sessiond");
 508         ret = send_error(KCONSUMERD_COMMAND_SOCK_READY);
 509         if (ret < 0) {
 510                 ERR("Error sending ready command to ltt-sessiond");
 511                 goto error;
 512         }
 513
 514         /* Blocking call, waiting for transmission */
 515         sock = lttcomm_accept_unix_sock(client_socket);
 516         if (sock <= 0) {
 517                 WARN("On accept, retrying");
 518                 goto error;
 519         }
 520         while (1) {
 521
 522                 /* We first get the number of fd we are about to receive */
 523                 ret = lttcomm_recv_unix_sock(sock, &tmp,
 524                                 sizeof(struct lttcomm_kconsumerd_header));
 525                 if (ret < 0) {
 526                         ERR("Receiving the lttcomm_kconsumerd_header, exiting");
 527                         goto error;
 528                 }
 529                 ret = consumerd_recv_fd(sock, tmp.payload_size, tmp.cmd_type);
 530                 if (ret < 0) {
 531                         ERR("Receiving the FD, exiting");
 532                         goto error;
 533                 }
 534         }
 535
 536 error:
 537         cleanup();
 538         return NULL;
 539 }
 540
 541 /*
 542  * update_poll_array
 543  *
 544  * Allocate the pollfd structure and the local view of the out fds
 545  * to avoid doing a lookup in the linked list and concurrency issues
 546  * when writing is needed.
 547  * Returns the number of fds in the structures
 548  */
 549 static int update_poll_array(struct pollfd **pollfd,
 550                 struct ltt_kconsumerd_fd **local_kconsumerd_fd)
 551 {
 552         struct ltt_kconsumerd_fd *iter;
 553         int i = 0;
 554
 555         if (*pollfd != NULL) {
 556                 free(*pollfd);
 557                 *pollfd = NULL;
 558         }
 559
 560         if (*local_kconsumerd_fd != NULL) {
 561                 free(*local_kconsumerd_fd);
 562                 *local_kconsumerd_fd = NULL;
 563         }
 564
 565         *pollfd = malloc(fds_count * sizeof(struct pollfd));
 566         if (*pollfd == NULL) {
 567                 perror("pollfd malloc");
 568                 goto error_mem;
 569         }
 570
 571         *local_kconsumerd_fd = malloc(fds_count * sizeof(struct ltt_kconsumerd_fd));
 572         if (*local_kconsumerd_fd == NULL) {
 573                 perror("local_kconsumerd_fd malloc");
 574                 goto error_mem;
 575         }
 576
 577         DBG("Updating poll fd array");
 578         pthread_mutex_lock(&kconsumerd_lock_fds);
 579
 580         cds_list_for_each_entry(iter, &kconsumerd_fd_list.head, list) {
 581                 DBG("Inside for each");
 582                 if (iter->state == ACTIVE_FD) {
 583                         DBG("Active FD %d", iter->consumerd_fd);
 584                         (*pollfd)[i].fd = iter->consumerd_fd;
 585                         (*pollfd)[i].events = POLLIN | POLLPRI;
 586                         local_kconsumerd_fd[i] = iter;
 587                         i++;
 588                 } else if (iter->state == DELETE_FD) {
 589                         del_fd(iter);
 590                 }
 591         }
 592         update_fd_array = 0;
 593         pthread_mutex_unlock(&kconsumerd_lock_fds);
 594         return i;
 595
 596 error_mem:
 597         return -ENOMEM;
 598 }
 599
 600 /*
 601  *  thread_poll_fds
 602  *
 603  *  This thread polls the fds in the ltt_fd_list to consume the data
 604  *  and write it to tracefile if necessary.
 605  */
 606 static void *thread_poll_fds(void *data)
 607 {
 608         int num_rdy, num_hup, high_prio, ret, i;
 609         struct pollfd *pollfd = NULL;
 610         /* local view of the fds */
 611         struct ltt_kconsumerd_fd *local_kconsumerd_fd = NULL;
 612         /* local view of fds_count */
 613         int nb_fd = 0;
 614
 615         ret = pipe(thread_pipe);
 616         if (ret < 0) {
 617                 perror("Error creating pipe");
 618                 goto end;
 619         }
 620
 621         while (1) {
 622                 high_prio = 0;
 623                 num_hup = 0;
 624
 625                 /*
 626                  * the ltt_fd_list has been updated, we need to update our
 627                  * local array as well
 628                  */
 629                 if (update_fd_array) {
 630                         ret = update_poll_array(&pollfd, &local_kconsumerd_fd);
 631                         if (ret < 0) {
 632                                 ERR("Error in allocating pollfd or local_outfds");
 633                                 send_error(KCONSUMERD_POLL_ERROR);
 634                                 goto end;
 635                         }
 636                         nb_fd = ret;
 637                 }
 638
 639                 /* poll on the array of fds */
 640                 DBG("polling on %d fd", nb_fd);
 641                 num_rdy = poll(pollfd, nb_fd, POLL_TIMEOUT);
 642                 DBG("poll num_rdy : %d", num_rdy);
 643                 if (num_rdy == -1) {
 644                         perror("Poll error");
 645                         send_error(KCONSUMERD_POLL_ERROR);
 646                         goto end;
 647                 }
 648
 649                 /* Take care of high priority channels first. */
 650                 for (i = 0; i < nb_fd; i++) {
 651                         switch(pollfd[i].revents) {
 652                                 case POLLERR:
 653                                         ERR("Error returned in polling fd %d.", pollfd[i].fd);
 654                                         num_hup++;
 655                                         send_error(KCONSUMERD_POLL_ERROR);
 656                                         break;
 657                                 case POLLHUP:
 658                                         ERR("Polling fd %d tells it has hung up.", pollfd[i].fd);
 659                                         num_hup++;
 660                                         break;
 661                                 case POLLNVAL:
 662                                         ERR("Polling fd %d tells fd is not open.", pollfd[i].fd);
 663                                         send_error(KCONSUMERD_POLL_NVAL);
 664                                         num_hup++;
 665                                         break;
 666                                 case POLLPRI:
 667                                         DBG("Urgent read on fd %d", pollfd[i].fd);
 668                                         high_prio = 1;
 669                                         ret = read_subbuffer(&local_kconsumerd_fd[i]);
 670                                         /* it's ok to have an unavailable sub-buffer (FIXME : is it ?) */
 671                                         if (ret == EAGAIN) {
 672                                                 ret = 0;
 673                                         }
 674                                         break;
 675                         }
 676                 }
 677
 678                 /* If every buffer FD has hung up, we end the read loop here */
 679                 if (nb_fd > 0 && num_hup == nb_fd) {
 680                         DBG("every buffer FD has hung up\n");
 681                         send_error(KCONSUMERD_POLL_HUP);
 682                         continue;
 683                 }
 684
 685                 /* Take care of low priority channels. */
 686                 if (!high_prio) {
 687                         for (i = 0; i < nb_fd; i++) {
 688                                 switch(pollfd[i].revents) {
 689                                         case POLLIN:
 690                                                 DBG("Normal read on fd %d", pollfd[i].fd);
 691                                                 ret = read_subbuffer(&local_kconsumerd_fd[i]);
 692                                                 /* it's ok to have an unavailable subbuffer (FIXME : is it ?) */
 693                                                 if (ret == EAGAIN) {
 694                                                         ret = 0;
 695                                                 }
 696                                                 break;
 697                                 }
 698                         }
 699                 }
 700         }
 701 end:
 702         if (pollfd != NULL) {
 703                 free(pollfd);
 704                 pollfd = NULL;
 705         }
 706         if (local_kconsumerd_fd != NULL) {
 707                 free(local_kconsumerd_fd);
 708                 local_kconsumerd_fd = NULL;
 709         }
 710         cleanup();
 711         return NULL;
 712 }
 713
 714 /*
 715  * usage function on stderr
 716  */
 717 static void usage(void)
 718 {
 719         fprintf(stderr, "Usage: %s OPTIONS\n\nOptions:\n", progname);
 720         fprintf(stderr, "  -h, --help                         "
 721                         "Display this usage.\n");
 722         fprintf(stderr, "  -c, --kconsumerd-cmd-sock PATH     "
 723                         "Specify path for the command socket\n");
 724         fprintf(stderr, "  -e, --kconsumerd-err-sock PATH     "
 725                         "Specify path for the error socket\n");
 726         fprintf(stderr, "  -d, --daemonize                    "
 727                         "Start as a daemon.\n");
 728         fprintf(stderr, "  -q, --quiet                        "
 729                         "No output at all.\n");
 730         fprintf(stderr, "  -v, --verbose                      "
 731                         "Verbose mode. Activate DBG() macro.\n");
 732         fprintf(stderr, "  -V, --version                      "
 733                         "Show version number.\n");
 734 }
 735
 736 /*
 737  * daemon argument parsing
 738  */
 739 static void parse_args(int argc, char **argv)
 740 {
 741         int c;
 742
 743         static struct option long_options[] = {
 744                 { "kconsumerd-cmd-sock", 1, 0, 'c' },
 745                 { "kconsumerd-err-sock", 1, 0, 'e' },
 746                 { "daemonize", 0, 0, 'd' },
 747                 { "help", 0, 0, 'h' },
 748                 { "quiet", 0, 0, 'q' },
 749                 { "verbose", 0, 0, 'v' },
 750                 { "version", 0, 0, 'V' },
 751                 { NULL, 0, 0, 0 }
 752         };
 753
 754         while (1) {
 755                 int option_index = 0;
 756                 c = getopt_long(argc, argv, "dhqvV" "c:e:", long_options, &option_index);
 757                 if (c == -1) {
 758                         break;
 759                 }
 760
 761                 switch (c) {
 762                         case 0:
 763                                 fprintf(stderr, "option %s", long_options[option_index].name);
 764                                 if (optarg) {
 765                                         fprintf(stderr, " with arg %s\n", optarg);
 766                                 }
 767                                 break;
 768                         case 'c':
 769                                 snprintf(command_sock_path, PATH_MAX, "%s", optarg);
 770                                 break;
 771                         case 'e':
 772                                 snprintf(error_sock_path, PATH_MAX, "%s", optarg);
 773                                 break;
 774                         case 'd':
 775                                 opt_daemon = 1;
 776                                 break;
 777                         case 'h':
 778                                 usage();
 779                                 exit(EXIT_FAILURE);
 780                         case 'q':
 781                                 opt_quiet = 1;
 782                                 break;
 783                         case 'v':
 784                                 opt_verbose = 1;
 785                                 break;
 786                         case 'V':
 787                                 fprintf(stdout, "%s\n", VERSION);
 788                                 exit(EXIT_SUCCESS);
 789                         default:
 790                                 usage();
 791                                 exit(EXIT_FAILURE);
 792                 }
 793         }
 794 }
 795
 796
 797 /*
 798  * main
 799  */
 800 int main(int argc, char **argv)
 801 {
 802         int i;
 803         int ret = 0;
 804         void *status;
 805
 806         /* Parse arguments */
 807         progname = argv[0];
 808         parse_args(argc, argv);
 809
 810         /* Daemonize */
 811         if (opt_daemon) {
 812                 ret = daemon(0, 0);
 813                 if (ret < 0) {
 814                         perror("daemon");
 815                         goto error;
 816                 }
 817         }
 818
 819         if (strlen(command_sock_path) == 0) {
 820                 snprintf(command_sock_path, PATH_MAX,
 821                                 KCONSUMERD_CMD_SOCK_PATH);
 822         }
 823         if (strlen(error_sock_path) == 0) {
 824                 snprintf(error_sock_path, PATH_MAX,
 825                                 KCONSUMERD_ERR_SOCK_PATH);
 826         }
 827
 828         if (set_signal_handler() < 0) {
 829                 goto error;
 830         }
 831
 832         /* Connect to the socket created by ltt-sessiond to report errors */
 833         DBG("Connecting to error socket %s", error_sock_path);
 834         error_socket = lttcomm_connect_unix_sock(error_sock_path);
 835         /* not a fatal error, but all communication with ltt-sessiond will fail */
 836         if (error_socket < 0) {
 837                 WARN("Cannot connect to error socket, is ltt-sessiond started ?");
 838         }
 839
 840         /* Create the thread to manage the receive of fd */
 841         ret = pthread_create(&threads[0], NULL, thread_receive_fds, (void *) NULL);
 842         if (ret != 0) {
 843                 perror("pthread_create");
 844                 goto error;
 845         }
 846
 847         /* Create thread to manage the polling/writing of traces */
 848         ret = pthread_create(&threads[1], NULL, thread_poll_fds, (void *) NULL);
 849         if (ret != 0) {
 850                 perror("pthread_create");
 851                 goto error;
 852         }
 853
 854         for (i = 0; i < 2; i++) {
 855                 ret = pthread_join(threads[i], &status);
 856                 if (ret != 0) {
 857                         perror("pthread_join");
 858                         goto error;
 859                 }
 860         }
 861         ret = EXIT_SUCCESS;
 862         send_error(KCONSUMERD_EXIT_SUCCESS);
 863         goto end;
 864
 865 error:
 866         ret = EXIT_FAILURE;
 867         send_error(KCONSUMERD_EXIT_FAILURE);
 868
 869 end:
 870         cleanup();
 871
 872         return ret;
 873 }