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