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 /* pipe to wake the poll thread when necessary */
  65 static int poll_pipe[2];
  66
  67 /* socket to communicate errors with sessiond */
  68 static int error_socket = -1;
  69
  70 /* to count the number of time the user pressed ctrl+c */
  71 static int sigintcount = 0;
  72
  73 /* flag to inform the polling thread to quit when all fd hung up */
  74 static int quit = 0;
  75
  76 /* Argument variables */
  77 int opt_quiet;
  78 int opt_verbose;
  79 static int opt_daemon;
  80 static const char *progname;
  81 static char command_sock_path[PATH_MAX]; /* Global command socket path */
  82 static char error_sock_path[PATH_MAX]; /* Global error path */
  83
  84 /*
  85  * del_fd
  86  *
  87  * Remove a fd from the global list protected by a mutex
  88  */
  89 static void del_fd(struct ltt_kconsumerd_fd *lcf)
  90 {
  91         DBG("Removing %d", lcf->consumerd_fd);
  92         pthread_mutex_lock(&kconsumerd_lock_fds);
  93         cds_list_del(&lcf->list);
  94         if (fds_count > 0) {
  95                 fds_count--;
  96                 DBG("Removed ltt_kconsumerd_fd");
  97                 if (lcf != NULL) {
  98                         close(lcf->out_fd);
  99                         close(lcf->consumerd_fd);
 100                         free(lcf);
 101                         lcf = NULL;
 102                 }
 103         }
 104         pthread_mutex_unlock(&kconsumerd_lock_fds);
 105 }
 106
 107 /*
 108  *  cleanup
 109  *
 110  *  Cleanup the daemon's socket on exit
 111  */
 112 static void cleanup()
 113 {
 114         struct ltt_kconsumerd_fd *iter;
 115
 116         /* remove the socket file */
 117         unlink(command_sock_path);
 118
 119         /* unblock the threads */
 120         WARN("Terminating the threads before exiting");
 121         pthread_cancel(threads[0]);
 122         pthread_cancel(threads[1]);
 123
 124         /* close all outfd */
 125         cds_list_for_each_entry(iter, &kconsumerd_fd_list.head, list) {
 126                 del_fd(iter);
 127         }
 128 }
 129
 130 /*
 131  * send_error
 132  *
 133  * send return code to ltt-sessiond
 134  */
 135 static int send_error(enum lttcomm_return_code cmd)
 136 {
 137         if (error_socket > 0) {
 138                 return lttcomm_send_unix_sock(error_socket, &cmd,
 139                                 sizeof(enum lttcomm_sessiond_command));
 140         } else {
 141                 return 0;
 142         }
 143 }
 144
 145 /*
 146  * add_fd
 147  *
 148  * Add a fd to the global list protected by a mutex
 149  */
 150 static int add_fd(struct lttcomm_kconsumerd_msg *buf, int consumerd_fd)
 151 {
 152         struct ltt_kconsumerd_fd *tmp_fd;
 153         int ret;
 154
 155         tmp_fd = malloc(sizeof(struct ltt_kconsumerd_fd));
 156         tmp_fd->sessiond_fd = buf->fd;
 157         tmp_fd->consumerd_fd = consumerd_fd;
 158         tmp_fd->state = buf->state;
 159         tmp_fd->max_sb_size = buf->max_sb_size;
 160         strncpy(tmp_fd->path_name, buf->path_name, PATH_MAX);
 161
 162         /* Opening the tracefile in write mode */
 163         DBG("Opening %s for writing", tmp_fd->path_name);
 164         ret = open(tmp_fd->path_name,
 165                         O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG|S_IRWXO);
 166         if (ret < 0) {
 167                 ERR("Opening %s", tmp_fd->path_name);
 168                 perror("open");
 169                 goto end;
 170         }
 171         tmp_fd->out_fd = ret;
 172         tmp_fd->out_fd_offset = 0;
 173
 174         DBG("Adding %s (%d, %d, %d)", tmp_fd->path_name,
 175                         tmp_fd->sessiond_fd, tmp_fd->consumerd_fd, tmp_fd->out_fd);
 176
 177         pthread_mutex_lock(&kconsumerd_lock_fds);
 178         cds_list_add(&tmp_fd->list, &kconsumerd_fd_list.head);
 179         fds_count++;
 180         pthread_mutex_unlock(&kconsumerd_lock_fds);
 181
 182 end:
 183         return ret;
 184 }
 185
 186
 187 /*
 188  *  sighandler
 189  *
 190  *  Signal handler for the daemon
 191  */
 192 static void sighandler(int sig)
 193 {
 194         if (sig == SIGINT && sigintcount++ == 0) {
 195                 DBG("ignoring first SIGINT");
 196                 return;
 197         }
 198
 199         cleanup();
 200
 201         return;
 202 }
 203
 204 /*
 205  *  set_signal_handler
 206  *
 207  *  Setup signal handler for :
 208  *      SIGINT, SIGTERM, SIGPIPE
 209  */
 210 static int set_signal_handler(void)
 211 {
 212         int ret = 0;
 213         struct sigaction sa;
 214         sigset_t sigset;
 215
 216         if ((ret = sigemptyset(&sigset)) < 0) {
 217                 perror("sigemptyset");
 218                 return ret;
 219         }
 220
 221         sa.sa_handler = sighandler;
 222         sa.sa_mask = sigset;
 223         sa.sa_flags = 0;
 224         if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
 225                 perror("sigaction");
 226                 return ret;
 227         }
 228
 229         if ((ret = sigaction(SIGINT, &sa, NULL)) < 0) {
 230                 perror("sigaction");
 231                 return ret;
 232         }
 233
 234         if ((ret = sigaction(SIGPIPE, &sa, NULL)) < 0) {
 235                 perror("sigaction");
 236                 return ret;
 237         }
 238
 239         return ret;
 240 }
 241
 242 /*
 243  * on_read_subbuffer
 244  *
 245  * Splice the data from the ring buffer to the tracefile.
 246  * Returns the number of bytes spliced
 247  */
 248 static int on_read_subbuffer(struct ltt_kconsumerd_fd *kconsumerd_fd,
 249                 unsigned long len)
 250 {
 251         long ret = 0;
 252         loff_t offset = 0;
 253         off_t orig_offset = kconsumerd_fd->out_fd_offset;
 254         int fd = kconsumerd_fd->consumerd_fd;
 255         int outfd = kconsumerd_fd->out_fd;
 256
 257         while (len > 0) {
 258                 DBG("splice chan to pipe offset %lu (fd : %d)",
 259                                 (unsigned long)offset, fd);
 260                 ret = splice(fd, &offset, thread_pipe[1], NULL, len,
 261                                 SPLICE_F_MOVE | SPLICE_F_MORE);
 262                 DBG("splice chan to pipe ret %ld", ret);
 263                 if (ret < 0) {
 264                         ret = errno;
 265                         perror("Error in relay splice");
 266                         goto splice_error;
 267                 }
 268
 269                 ret = splice(thread_pipe[0], NULL, outfd, NULL, ret,
 270                                 SPLICE_F_MOVE | SPLICE_F_MORE);
 271                 DBG("splice pipe to file %ld", ret);
 272                 if (ret < 0) {
 273                         ret = errno;
 274                         perror("Error in file splice");
 275                         goto splice_error;
 276                 }
 277                 if (ret >= len) {
 278                         len = 0;
 279                 }
 280                 /* This won't block, but will start writeout asynchronously */
 281                 sync_file_range(outfd, kconsumerd_fd->out_fd_offset, ret,
 282                                 SYNC_FILE_RANGE_WRITE);
 283                 kconsumerd_fd->out_fd_offset += ret;
 284         }
 285
 286         /*
 287          * This does a blocking write-and-wait on any page that belongs to the
 288          * subbuffer prior to the one we just wrote.
 289          * Don't care about error values, as these are just hints and ways to
 290          * limit the amount of page cache used.
 291          */
 292         if (orig_offset >= kconsumerd_fd->max_sb_size) {
 293                 sync_file_range(outfd, orig_offset - kconsumerd_fd->max_sb_size,
 294                                 kconsumerd_fd->max_sb_size,
 295                                 SYNC_FILE_RANGE_WAIT_BEFORE
 296                                 | SYNC_FILE_RANGE_WRITE
 297                                 | SYNC_FILE_RANGE_WAIT_AFTER);
 298                 /*
 299                  * Give hints to the kernel about how we access the file:
 300                  * POSIX_FADV_DONTNEED : we won't re-access data in a near
 301                  * future after we write it.
 302                  * We need to call fadvise again after the file grows because
 303                  * the kernel does not seem to apply fadvise to non-existing
 304                  * parts of the file.
 305                  * Call fadvise _after_ having waited for the page writeback to
 306                  * complete because the dirty page writeback semantic is not
 307                  * well defined. So it can be expected to lead to lower
 308                  * throughput in streaming.
 309                  */
 310                 posix_fadvise(outfd, orig_offset - kconsumerd_fd->max_sb_size,
 311                                 kconsumerd_fd->max_sb_size, POSIX_FADV_DONTNEED);
 312         }
 313         goto end;
 314
 315 splice_error:
 316         /* send the appropriate error description to sessiond */
 317         switch(ret) {
 318         case EBADF:
 319                 send_error(KCONSUMERD_SPLICE_EBADF);
 320                 break;
 321         case EINVAL:
 322                 send_error(KCONSUMERD_SPLICE_EINVAL);
 323                 break;
 324         case ENOMEM:
 325                 send_error(KCONSUMERD_SPLICE_ENOMEM);
 326                 break;
 327         case ESPIPE:
 328                 send_error(KCONSUMERD_SPLICE_ESPIPE);
 329                 break;
 330         }
 331
 332 end:
 333         return ret;
 334 }
 335
 336 /*
 337  * read_subbuffer
 338  *
 339  * Consume data on a file descriptor and write it on a trace file
 340  */
 341 static int read_subbuffer(struct ltt_kconsumerd_fd *kconsumerd_fd)
 342 {
 343         unsigned long len;
 344         int err;
 345         long ret = 0;
 346         int infd = kconsumerd_fd->consumerd_fd;
 347
 348         DBG("In read_subbuffer (infd : %d)", infd);
 349         /* Get the next subbuffer */
 350         err = kernctl_get_next_subbuf(infd);
 351         if (err != 0) {
 352                 ret = errno;
 353                 perror("Reserving sub buffer failed (everything is normal, "
 354                                 "it is due to concurrency)");
 355                 goto end;
 356         }
 357
 358         /* read the whole subbuffer */
 359         err = kernctl_get_padded_subbuf_size(infd, &len);
 360         if (err != 0) {
 361                 ret = errno;
 362                 perror("Getting sub-buffer len failed.");
 363                 goto end;
 364         }
 365
 366         /* splice the subbuffer to the tracefile */
 367         ret = on_read_subbuffer(kconsumerd_fd, len);
 368         if (ret < 0) {
 369                 /*
 370                  * display the error but continue processing to try
 371                  * to release the subbuffer
 372                  */
 373                 ERR("Error splicing to tracefile");
 374         }
 375
 376         err = kernctl_put_next_subbuf(infd);
 377         if (err != 0) {
 378                 ret = errno;
 379                 if (errno == EFAULT) {
 380                         perror("Error in unreserving sub buffer\n");
 381                 } else if (errno == EIO) {
 382                         /* Should never happen with newer LTTng versions */
 383                         perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
 384                 }
 385                 goto end;
 386         }
 387
 388 end:
 389         return ret;
 390 }
 391
 392 /*
 393  * change_fd_state
 394  *
 395  * Update a fd according to what we just received
 396  */
 397 static void change_fd_state(int sessiond_fd,
 398                 enum kconsumerd_fd_state state)
 399 {
 400         struct ltt_kconsumerd_fd *iter;
 401         cds_list_for_each_entry(iter, &kconsumerd_fd_list.head, list) {
 402                 if (iter->sessiond_fd == sessiond_fd) {
 403                         iter->state = state;
 404                         break;
 405                 }
 406         }
 407 }
 408
 409 /*
 410  * consumerd_recv_fd
 411  *
 412  * Receives an array of file descriptors and the associated
 413  * structures describing each fd (path name).
 414  * Returns the size of received data
 415  */
 416 static int consumerd_recv_fd(int sfd, int size,
 417                 enum kconsumerd_command cmd_type)
 418 {
 419         struct msghdr msg;
 420         struct iovec iov[1];
 421         int ret = 0, i, tmp2;
 422         struct cmsghdr *cmsg;
 423         int nb_fd;
 424         char recv_fd[CMSG_SPACE(sizeof(int))];
 425         struct lttcomm_kconsumerd_msg lkm;
 426
 427         /* the number of fds we are about to receive */
 428         nb_fd = size / sizeof(struct lttcomm_kconsumerd_msg);
 429
 430         for (i = 0; i < nb_fd; i++) {
 431                 memset(&msg, 0, sizeof(msg));
 432
 433                 /* Prepare to receive the structures */
 434                 iov[0].iov_base = &lkm;
 435                 iov[0].iov_len = sizeof(lkm);
 436                 msg.msg_iov = iov;
 437                 msg.msg_iovlen = 1;
 438
 439                 msg.msg_control = recv_fd;
 440                 msg.msg_controllen = sizeof(recv_fd);
 441
 442                 DBG("Waiting to receive fd");
 443                 if ((ret = recvmsg(sfd, &msg, 0)) < 0) {
 444                         perror("recvmsg");
 445                         continue;
 446                 }
 447
 448                 if (ret != (size / nb_fd)) {
 449                         ERR("Received only %d, expected %d", ret, size);
 450                         send_error(KCONSUMERD_ERROR_RECV_FD);
 451                         goto end;
 452                 }
 453
 454                 cmsg = CMSG_FIRSTHDR(&msg);
 455                 if (!cmsg) {
 456                         ERR("Invalid control message header");
 457                         ret = -1;
 458                         send_error(KCONSUMERD_ERROR_RECV_FD);
 459                         goto end;
 460                 }
 461
 462                 /* if we received fds */
 463                 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
 464                         switch (cmd_type) {
 465                         case ADD_STREAM:
 466                                 DBG("add_fd %s (%d)", lkm.path_name, (CMSG_DATA(cmsg)[0]));
 467                                 ret = add_fd(&lkm, (CMSG_DATA(cmsg)[0]));
 468                                 if (ret < 0) {
 469                                         send_error(KCONSUMERD_OUTFD_ERROR);
 470                                         goto end;
 471                                 }
 472                                 break;
 473                         case UPDATE_STREAM:
 474                                 change_fd_state(lkm.fd, lkm.state);
 475                                 break;
 476                         default:
 477                                 break;
 478                         }
 479                         /* flag to tell the polling thread to update its fd array */
 480                         update_fd_array = 1;
 481                         /* signal the poll thread */
 482                         tmp2 = write(poll_pipe[1], "4", 1);
 483                 } else {
 484                         ERR("Didn't received any fd");
 485                         send_error(KCONSUMERD_ERROR_RECV_FD);
 486                         ret = -1;
 487                         goto end;
 488                 }
 489         }
 490
 491 end:
 492         DBG("consumerd_recv_fd thread exiting");
 493         return ret;
 494 }
 495
 496 /*
 497  *  thread_receive_fds
 498  *
 499  *  This thread listens on the consumerd socket and
 500  *  receives the file descriptors from ltt-sessiond
 501  */
 502 static void *thread_receive_fds(void *data)
 503 {
 504         int sock, client_socket, ret;
 505         struct lttcomm_kconsumerd_header tmp;
 506
 507         DBG("Creating command socket %s", command_sock_path);
 508         unlink(command_sock_path);
 509         client_socket = lttcomm_create_unix_sock(command_sock_path);
 510         if (client_socket < 0) {
 511                 ERR("Cannot create command socket");
 512                 goto end;
 513         }
 514
 515         ret = lttcomm_listen_unix_sock(client_socket);
 516         if (ret < 0) {
 517                 goto end;
 518         }
 519
 520         DBG("Sending ready command to ltt-sessiond");
 521         ret = send_error(KCONSUMERD_COMMAND_SOCK_READY);
 522         if (ret < 0) {
 523                 ERR("Error sending ready command to ltt-sessiond");
 524                 goto end;
 525         }
 526
 527         /* Blocking call, waiting for transmission */
 528         sock = lttcomm_accept_unix_sock(client_socket);
 529         if (sock <= 0) {
 530                 WARN("On accept");
 531                 goto end;
 532         }
 533         while (1) {
 534                 /* We first get the number of fd we are about to receive */
 535                 ret = lttcomm_recv_unix_sock(sock, &tmp,
 536                                 sizeof(struct lttcomm_kconsumerd_header));
 537                 if (ret <= 0) {
 538                         ERR("Communication interrupted on command socket");
 539                         goto end;
 540                 }
 541                 if (tmp.cmd_type == STOP) {
 542                         DBG("Received STOP command");
 543                         goto end;
 544                 }
 545                 /* we received a command to add or update fds */
 546                 ret = consumerd_recv_fd(sock, tmp.payload_size, tmp.cmd_type);
 547                 if (ret <= 0) {
 548                         ERR("Receiving the FD, exiting");
 549                         goto end;
 550                 }
 551         }
 552
 553 end:
 554         DBG("thread_receive_fds exiting");
 555         quit = 1;
 556         ret = write(poll_pipe[1], "4", 1);
 557         if (ret < 0) {
 558                 perror("poll pipe write");
 559         }
 560         return NULL;
 561 }
 562
 563 /*
 564  * update_poll_array
 565  *
 566  * Allocate the pollfd structure and the local view of the out fds
 567  * to avoid doing a lookup in the linked list and concurrency issues
 568  * when writing is needed.
 569  * Returns the number of fds in the structures
 570  */
 571 static int update_poll_array(struct pollfd **pollfd,
 572                 struct ltt_kconsumerd_fd **local_kconsumerd_fd)
 573 {
 574         struct ltt_kconsumerd_fd *iter;
 575         int i = 0;
 576
 577
 578         DBG("Updating poll fd array");
 579         pthread_mutex_lock(&kconsumerd_lock_fds);
 580
 581         cds_list_for_each_entry(iter, &kconsumerd_fd_list.head, list) {
 582                 DBG("Inside for each");
 583                 if (iter->state == ACTIVE_FD) {
 584                         DBG("Active FD %d", iter->consumerd_fd);
 585                         (*pollfd)[i].fd = iter->consumerd_fd;
 586                         (*pollfd)[i].events = POLLIN | POLLPRI;
 587                         local_kconsumerd_fd[i] = iter;
 588                         i++;
 589                 }
 590         }
 591         /*
 592          * insert the poll_pipe at the end of the array and don't increment i
 593          * so nb_fd is the number of real FD
 594          */
 595         (*pollfd)[i].fd = poll_pipe[0];
 596         (*pollfd)[i].events = POLLIN;
 597
 598         update_fd_array = 0;
 599         pthread_mutex_unlock(&kconsumerd_lock_fds);
 600         return i;
 601
 602 }
 603
 604 /*
 605  *  thread_poll_fds
 606  *
 607  *  This thread polls the fds in the ltt_fd_list to consume the data
 608  *  and write it to tracefile if necessary.
 609  */
 610 static void *thread_poll_fds(void *data)
 611 {
 612         int num_rdy, num_hup, high_prio, ret, i;
 613         struct pollfd *pollfd = NULL;
 614         /* local view of the fds */
 615         struct ltt_kconsumerd_fd **local_kconsumerd_fd = NULL;
 616         /* local view of fds_count */
 617         int nb_fd = 0;
 618         char tmp;
 619         int tmp2;
 620
 621         ret = pipe(thread_pipe);
 622         if (ret < 0) {
 623                 perror("Error creating pipe");
 624                 goto end;
 625         }
 626
 627         local_kconsumerd_fd = malloc(sizeof(struct ltt_kconsumerd_fd));
 628
 629         while (1) {
 630                 high_prio = 0;
 631                 num_hup = 0;
 632
 633                 /*
 634                  * the ltt_fd_list has been updated, we need to update our
 635                  * local array as well
 636                  */
 637                 if (update_fd_array == 1) {
 638                         if (pollfd != NULL) {
 639                                 free(pollfd);
 640                                 pollfd = NULL;
 641                         }
 642                         if (local_kconsumerd_fd != NULL) {
 643                                 free(local_kconsumerd_fd);
 644                                 local_kconsumerd_fd = NULL;
 645                         }
 646                         /* allocate for all fds + 1 for the poll_pipe */
 647                         pollfd = malloc((fds_count + 1) * sizeof(struct pollfd));
 648                         if (pollfd == NULL) {
 649                                 perror("pollfd malloc");
 650                                 goto end;
 651                         }
 652                         /* allocate for all fds + 1 for the poll_pipe */
 653                         local_kconsumerd_fd = malloc((fds_count + 1) * sizeof(struct ltt_kconsumerd_fd));
 654                         if (local_kconsumerd_fd == NULL) {
 655                                 perror("local_kconsumerd_fd malloc");
 656                                 goto end;
 657                         }
 658
 659                         ret = update_poll_array(&pollfd, local_kconsumerd_fd);
 660                         if (ret < 0) {
 661                                 ERR("Error in allocating pollfd or local_outfds");
 662                                 send_error(KCONSUMERD_POLL_ERROR);
 663                                 goto end;
 664                         }
 665                         nb_fd = ret;
 666                 }
 667
 668                 /* poll on the array of fds */
 669                 DBG("polling on %d fd", nb_fd + 1);
 670                 num_rdy = poll(pollfd, nb_fd + 1, -1);
 671                 DBG("poll num_rdy : %d", num_rdy);
 672                 if (num_rdy == -1) {
 673                         perror("Poll error");
 674                         send_error(KCONSUMERD_POLL_ERROR);
 675                         goto end;
 676                 }
 677
 678                 /* No FDs and quit, cleanup the thread */
 679                 if (nb_fd == 0 && quit == 1) {
 680                         goto end;
 681                 }
 682
 683                 /*
 684                  * if only the poll_pipe triggered poll to return just return to the
 685                  * beginning of the loop to update the array
 686                  */
 687                 if (num_rdy == 1 && pollfd[nb_fd].revents == POLLIN) {
 688                         DBG("poll_pipe wake up");
 689                         tmp2 = read(poll_pipe[0], &tmp, 1);
 690                         continue;
 691                 }
 692
 693                 /* Take care of high priority channels first. */
 694                 for (i = 0; i < nb_fd; i++) {
 695                         switch(pollfd[i].revents) {
 696                         case POLLERR:
 697                                 ERR("Error returned in polling fd %d.", pollfd[i].fd);
 698                                 del_fd(local_kconsumerd_fd[i]);
 699                                 update_fd_array = 1;
 700                                 num_hup++;
 701                                 break;
 702                         case POLLHUP:
 703                                 ERR("Polling fd %d tells it has hung up.", pollfd[i].fd);
 704                                 del_fd(local_kconsumerd_fd[i]);
 705                                 update_fd_array = 1;
 706                                 num_hup++;
 707                                 break;
 708                         case POLLNVAL:
 709                                 ERR("Polling fd %d tells fd is not open.", pollfd[i].fd);
 710                                 del_fd(local_kconsumerd_fd[i]);
 711                                 update_fd_array = 1;
 712                                 num_hup++;
 713                                 break;
 714                         case POLLPRI:
 715                                 DBG("Urgent read on fd %d", pollfd[i].fd);
 716                                 high_prio = 1;
 717                                 ret = read_subbuffer(local_kconsumerd_fd[i]);
 718                                 /* it's ok to have an unavailable sub-buffer (FIXME : is it ?) */
 719                                 if (ret == EAGAIN) {
 720                                         ret = 0;
 721                                 }
 722                                 break;
 723                         }
 724                 }
 725
 726                 /* If every buffer FD has hung up, we end the read loop here */
 727                 if (nb_fd > 0 && num_hup == nb_fd) {
 728                         DBG("every buffer FD has hung up\n");
 729                         if (quit == 1) {
 730                                 goto end;
 731                         }
 732                         continue;
 733                 }
 734
 735                 /* Take care of low priority channels. */
 736                 if (high_prio == 0) {
 737                         for (i = 0; i < nb_fd; i++) {
 738                                 if (pollfd[i].revents == POLLIN) {
 739                                         DBG("Normal read on fd %d", pollfd[i].fd);
 740                                         ret = read_subbuffer(local_kconsumerd_fd[i]);
 741                                         /* it's ok to have an unavailable subbuffer (FIXME : is it ?) */
 742                                         if (ret == EAGAIN) {
 743                                                 ret = 0;
 744                                         }
 745                                 }
 746                         }
 747                 }
 748         }
 749 end:
 750         DBG("polling thread exiting");
 751         if (pollfd != NULL) {
 752                 free(pollfd);
 753                 pollfd = NULL;
 754         }
 755         if (local_kconsumerd_fd != NULL) {
 756                 free(local_kconsumerd_fd);
 757                 local_kconsumerd_fd = NULL;
 758         }
 759         cleanup();
 760         return NULL;
 761 }
 762
 763 /*
 764  * usage function on stderr
 765  */
 766 static void usage(void)
 767 {
 768         fprintf(stderr, "Usage: %s OPTIONS\n\nOptions:\n", progname);
 769         fprintf(stderr, "  -h, --help                         "
 770                         "Display this usage.\n");
 771         fprintf(stderr, "  -c, --kconsumerd-cmd-sock PATH     "
 772                         "Specify path for the command socket\n");
 773         fprintf(stderr, "  -e, --kconsumerd-err-sock PATH     "
 774                         "Specify path for the error socket\n");
 775         fprintf(stderr, "  -d, --daemonize                    "
 776                         "Start as a daemon.\n");
 777         fprintf(stderr, "  -q, --quiet                        "
 778                         "No output at all.\n");
 779         fprintf(stderr, "  -v, --verbose                      "
 780                         "Verbose mode. Activate DBG() macro.\n");
 781         fprintf(stderr, "  -V, --version                      "
 782                         "Show version number.\n");
 783 }
 784
 785 /*
 786  * daemon argument parsing
 787  */
 788 static void parse_args(int argc, char **argv)
 789 {
 790         int c;
 791
 792         static struct option long_options[] = {
 793                 { "kconsumerd-cmd-sock", 1, 0, 'c' },
 794                 { "kconsumerd-err-sock", 1, 0, 'e' },
 795                 { "daemonize", 0, 0, 'd' },
 796                 { "help", 0, 0, 'h' },
 797                 { "quiet", 0, 0, 'q' },
 798                 { "verbose", 0, 0, 'v' },
 799                 { "version", 0, 0, 'V' },
 800                 { NULL, 0, 0, 0 }
 801         };
 802
 803         while (1) {
 804                 int option_index = 0;
 805                 c = getopt_long(argc, argv, "dhqvV" "c:e:", long_options, &option_index);
 806                 if (c == -1) {
 807                         break;
 808                 }
 809
 810                 switch (c) {
 811                 case 0:
 812                         fprintf(stderr, "option %s", long_options[option_index].name);
 813                         if (optarg) {
 814                                 fprintf(stderr, " with arg %s\n", optarg);
 815                         }
 816                         break;
 817                 case 'c':
 818                         snprintf(command_sock_path, PATH_MAX, "%s", optarg);
 819                         break;
 820                 case 'e':
 821                         snprintf(error_sock_path, PATH_MAX, "%s", optarg);
 822                         break;
 823                 case 'd':
 824                         opt_daemon = 1;
 825                         break;
 826                 case 'h':
 827                         usage();
 828                         exit(EXIT_FAILURE);
 829                 case 'q':
 830                         opt_quiet = 1;
 831                         break;
 832                 case 'v':
 833                         opt_verbose = 1;
 834                         break;
 835                 case 'V':
 836                         fprintf(stdout, "%s\n", VERSION);
 837                         exit(EXIT_SUCCESS);
 838                 default:
 839                         usage();
 840                         exit(EXIT_FAILURE);
 841                 }
 842         }
 843 }
 844
 845
 846 /*
 847  * main
 848  */
 849 int main(int argc, char **argv)
 850 {
 851         int i;
 852         int ret = 0;
 853         void *status;
 854
 855         /* Parse arguments */
 856         progname = argv[0];
 857         parse_args(argc, argv);
 858
 859         /* Daemonize */
 860         if (opt_daemon) {
 861                 ret = daemon(0, 0);
 862                 if (ret < 0) {
 863                         perror("daemon");
 864                         goto error;
 865                 }
 866         }
 867
 868         if (strlen(command_sock_path) == 0) {
 869                 snprintf(command_sock_path, PATH_MAX,
 870                                 KCONSUMERD_CMD_SOCK_PATH);
 871         }
 872         if (strlen(error_sock_path) == 0) {
 873                 snprintf(error_sock_path, PATH_MAX,
 874                                 KCONSUMERD_ERR_SOCK_PATH);
 875         }
 876
 877         if (set_signal_handler() < 0) {
 878                 goto error;
 879         }
 880
 881         /* create the pipe to wake to polling thread when needed */
 882         ret = pipe(poll_pipe);
 883         if (ret < 0) {
 884                 perror("Error creating poll pipe");
 885                 goto end;
 886         }
 887
 888         /* Connect to the socket created by ltt-sessiond to report errors */
 889         DBG("Connecting to error socket %s", error_sock_path);
 890         error_socket = lttcomm_connect_unix_sock(error_sock_path);
 891         /* not a fatal error, but all communication with ltt-sessiond will fail */
 892         if (error_socket < 0) {
 893                 WARN("Cannot connect to error socket, is ltt-sessiond started ?");
 894         }
 895
 896         /* Create the thread to manage the receive of fd */
 897         ret = pthread_create(&threads[0], NULL, thread_receive_fds, (void *) NULL);
 898         if (ret != 0) {
 899                 perror("pthread_create");
 900                 goto error;
 901         }
 902
 903         /* Create thread to manage the polling/writing of traces */
 904         ret = pthread_create(&threads[1], NULL, thread_poll_fds, (void *) NULL);
 905         if (ret != 0) {
 906                 perror("pthread_create");
 907                 goto error;
 908         }
 909
 910         for (i = 0; i < 2; i++) {
 911                 ret = pthread_join(threads[i], &status);
 912                 if (ret != 0) {
 913                         perror("pthread_join");
 914                         goto error;
 915                 }
 916         }
 917         ret = EXIT_SUCCESS;
 918         send_error(KCONSUMERD_EXIT_SUCCESS);
 919         goto end;
 920
 921 error:
 922         ret = EXIT_FAILURE;
 923         send_error(KCONSUMERD_EXIT_FAILURE);
 924
 925 end:
 926         cleanup();
 927
 928         return ret;
 929 }