ltt-kconsumerd/ltt-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; only version 2
   8  * of the License.
   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 #include <sys/mman.h>
  39 #include <assert.h>
  40
  41 #include <lttng/lttng-kconsumerd.h>
  42
  43 #include "lttngerr.h"
  44 #include "kernelctl.h"
  45 #include "ltt-kconsumerd.h"
  46 #include "lttng-sessiond-comm.h"
  47
  48 /* the two threads (receive fd and poll) */
  49 static pthread_t threads[2];
  50
  51 /* to count the number of time the user pressed ctrl+c */
  52 static int sigintcount = 0;
  53
  54 /* Argument variables */
  55 int opt_quiet;
  56 int opt_verbose;
  57 static int opt_daemon;
  58 static const char *progname;
  59 static char command_sock_path[PATH_MAX]; /* Global command socket path */
  60 static char error_sock_path[PATH_MAX]; /* Global error path */
  61
  62 /* the liblttngkconsumerd context */
  63 static struct lttng_kconsumerd_local_data *ctx;
  64
  65 /*
  66  * Signal handler for the daemon
  67  */
  68 static void sighandler(int sig)
  69 {
  70         if (sig == SIGINT && sigintcount++ == 0) {
  71                 DBG("ignoring first SIGINT");
  72                 return;
  73         }
  74
  75         lttng_kconsumerd_should_exit(ctx);
  76 }
  77
  78 /*
  79  * Setup signal handler for :
  80  *      SIGINT, SIGTERM, SIGPIPE
  81  */
  82 static int set_signal_handler(void)
  83 {
  84         int ret = 0;
  85         struct sigaction sa;
  86         sigset_t sigset;
  87
  88         if ((ret = sigemptyset(&sigset)) < 0) {
  89                 perror("sigemptyset");
  90                 return ret;
  91         }
  92
  93         sa.sa_handler = sighandler;
  94         sa.sa_mask = sigset;
  95         sa.sa_flags = 0;
  96         if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
  97                 perror("sigaction");
  98                 return ret;
  99         }
 100
 101         if ((ret = sigaction(SIGINT, &sa, NULL)) < 0) {
 102                 perror("sigaction");
 103                 return ret;
 104         }
 105
 106         if ((ret = sigaction(SIGPIPE, &sa, NULL)) < 0) {
 107                 perror("sigaction");
 108                 return ret;
 109         }
 110
 111         return ret;
 112 }
 113
 114 /*
 115  * usage function on stderr
 116  */
 117 static void usage(void)
 118 {
 119         fprintf(stderr, "Usage: %s OPTIONS\n\nOptions:\n", progname);
 120         fprintf(stderr, "  -h, --help                         "
 121                         "Display this usage.\n");
 122         fprintf(stderr, "  -c, --kconsumerd-cmd-sock PATH     "
 123                         "Specify path for the command socket\n");
 124         fprintf(stderr, "  -e, --kconsumerd-err-sock PATH     "
 125                         "Specify path for the error socket\n");
 126         fprintf(stderr, "  -d, --daemonize                    "
 127                         "Start as a daemon.\n");
 128         fprintf(stderr, "  -q, --quiet                        "
 129                         "No output at all.\n");
 130         fprintf(stderr, "  -v, --verbose                      "
 131                         "Verbose mode. Activate DBG() macro.\n");
 132         fprintf(stderr, "  -V, --version                      "
 133                         "Show version number.\n");
 134 }
 135
 136 /*
 137  * daemon argument parsing
 138  */
 139 static void parse_args(int argc, char **argv)
 140 {
 141         int c;
 142
 143         static struct option long_options[] = {
 144                 { "kconsumerd-cmd-sock", 1, 0, 'c' },
 145                 { "kconsumerd-err-sock", 1, 0, 'e' },
 146                 { "daemonize", 0, 0, 'd' },
 147                 { "help", 0, 0, 'h' },
 148                 { "quiet", 0, 0, 'q' },
 149                 { "verbose", 0, 0, 'v' },
 150                 { "version", 0, 0, 'V' },
 151                 { NULL, 0, 0, 0 }
 152         };
 153
 154         while (1) {
 155                 int option_index = 0;
 156                 c = getopt_long(argc, argv, "dhqvV" "c:e:", long_options, &option_index);
 157                 if (c == -1) {
 158                         break;
 159                 }
 160
 161                 switch (c) {
 162                 case 0:
 163                         fprintf(stderr, "option %s", long_options[option_index].name);
 164                         if (optarg) {
 165                                 fprintf(stderr, " with arg %s\n", optarg);
 166                         }
 167                         break;
 168                 case 'c':
 169                         snprintf(command_sock_path, PATH_MAX, "%s", optarg);
 170                         break;
 171                 case 'e':
 172                         snprintf(error_sock_path, PATH_MAX, "%s", optarg);
 173                         break;
 174                 case 'd':
 175                         opt_daemon = 1;
 176                         break;
 177                 case 'h':
 178                         usage();
 179                         exit(EXIT_FAILURE);
 180                 case 'q':
 181                         opt_quiet = 1;
 182                         break;
 183                 case 'v':
 184                         opt_verbose = 1;
 185                         break;
 186                 case 'V':
 187                         fprintf(stdout, "%s\n", VERSION);
 188                         exit(EXIT_SUCCESS);
 189                 default:
 190                         usage();
 191                         exit(EXIT_FAILURE);
 192                 }
 193         }
 194 }
 195
 196 /*
 197  * Consume data on a file descriptor and write it on a trace file.
 198  */
 199 static int read_subbuffer(struct lttng_kconsumerd_fd *kconsumerd_fd)
 200 {
 201         unsigned long len;
 202         int err;
 203         long ret = 0;
 204         int infd = kconsumerd_fd->consumerd_fd;
 205
 206         DBG("In kconsumerd_read_subbuffer (infd : %d)", infd);
 207         /* Get the next subbuffer */
 208         err = kernctl_get_next_subbuf(infd);
 209         if (err != 0) {
 210                 ret = errno;
 211                 /*
 212                  * This is a debug message even for single-threaded consumer,
 213                  * because poll() have more relaxed criterions than get subbuf,
 214                  * so get_subbuf may fail for short race windows where poll()
 215                  * would issue wakeups.
 216                  */
 217                 DBG("Reserving sub buffer failed (everything is normal, "
 218                                 "it is due to concurrency)");
 219                 goto end;
 220         }
 221
 222         switch (kconsumerd_fd->output) {
 223                 case LTTNG_EVENT_SPLICE:
 224                         /* read the whole subbuffer */
 225                         err = kernctl_get_padded_subbuf_size(infd, &len);
 226                         if (err != 0) {
 227                                 ret = errno;
 228                                 perror("Getting sub-buffer len failed.");
 229                                 goto end;
 230                         }
 231
 232                         /* splice the subbuffer to the tracefile */
 233                         ret = lttng_kconsumerd_on_read_subbuffer_splice(ctx, kconsumerd_fd, len);
 234                         if (ret < 0) {
 235                                 /*
 236                                  * display the error but continue processing to try
 237                                  * to release the subbuffer
 238                                  */
 239                                 ERR("Error splicing to tracefile");
 240                         }
 241                         break;
 242                 case LTTNG_EVENT_MMAP:
 243                         /* read the used subbuffer size */
 244                         err = kernctl_get_padded_subbuf_size(infd, &len);
 245                         if (err != 0) {
 246                                 ret = errno;
 247                                 perror("Getting sub-buffer len failed.");
 248                                 goto end;
 249                         }
 250                         /* write the subbuffer to the tracefile */
 251                         ret = lttng_kconsumerd_on_read_subbuffer_mmap(ctx, kconsumerd_fd, len);
 252                         if (ret < 0) {
 253                                 /*
 254                                  * display the error but continue processing to try
 255                                  * to release the subbuffer
 256                                  */
 257                                 ERR("Error writing to tracefile");
 258                         }
 259                         break;
 260                 default:
 261                         ERR("Unknown output method");
 262                         ret = -1;
 263         }
 264
 265         err = kernctl_put_next_subbuf(infd);
 266         if (err != 0) {
 267                 ret = errno;
 268                 if (errno == EFAULT) {
 269                         perror("Error in unreserving sub buffer\n");
 270                 } else if (errno == EIO) {
 271                         /* Should never happen with newer LTTng versions */
 272                         perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
 273                 }
 274                 goto end;
 275         }
 276
 277 end:
 278         return ret;
 279 }
 280
 281 static int on_recv_fd(struct lttng_kconsumerd_fd *kconsumerd_fd)
 282 {
 283         int ret;
 284
 285         /* Opening the tracefile in write mode */
 286         if (kconsumerd_fd->path_name != NULL) {
 287                 ret = open(kconsumerd_fd->path_name,
 288                                 O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG|S_IRWXO);
 289                 if (ret < 0) {
 290                         ERR("Opening %s", kconsumerd_fd->path_name);
 291                         perror("open");
 292                         goto error;
 293                 }
 294                 kconsumerd_fd->out_fd = ret;
 295         }
 296
 297         if (kconsumerd_fd->output == LTTNG_EVENT_MMAP) {
 298                 /* get the len of the mmap region */
 299                 ret = kernctl_get_mmap_len(kconsumerd_fd->consumerd_fd, &kconsumerd_fd->mmap_len);
 300                 if (ret != 0) {
 301                         ret = errno;
 302                         perror("kernctl_get_mmap_len");
 303                         goto error_close_fd;
 304                 }
 305
 306                 kconsumerd_fd->mmap_base = mmap(NULL, kconsumerd_fd->mmap_len,
 307                                 PROT_READ, MAP_PRIVATE, kconsumerd_fd->consumerd_fd, 0);
 308                 if (kconsumerd_fd->mmap_base == MAP_FAILED) {
 309                         perror("Error mmaping");
 310                         ret = -1;
 311                         goto error_close_fd;
 312                 }
 313         }
 314
 315         /* we return 0 to let the library handle the FD internally */
 316         return 0;
 317
 318 error_close_fd:
 319         {
 320                 int err;
 321
 322                 err = close(kconsumerd_fd->out_fd);
 323                 assert(!err);
 324         }
 325 error:
 326         return ret;
 327 }
 328
 329 /*
 330  * main
 331  */
 332 int main(int argc, char **argv)
 333 {
 334         int i;
 335         int ret = 0;
 336         void *status;
 337
 338         /* Parse arguments */
 339         progname = argv[0];
 340         parse_args(argc, argv);
 341
 342         /* Daemonize */
 343         if (opt_daemon) {
 344                 ret = daemon(0, 0);
 345                 if (ret < 0) {
 346                         perror("daemon");
 347                         goto error;
 348                 }
 349         }
 350
 351         if (strlen(command_sock_path) == 0) {
 352                 snprintf(command_sock_path, PATH_MAX,
 353                                 KCONSUMERD_CMD_SOCK_PATH);
 354         }
 355         /* create the consumer instance with and assign the callbacks */
 356         ctx = lttng_kconsumerd_create(read_subbuffer, on_recv_fd, NULL);
 357         if (ctx == NULL) {
 358                 goto error;
 359         }
 360
 361         lttng_kconsumerd_set_command_sock_path(ctx, command_sock_path);
 362         if (strlen(error_sock_path) == 0) {
 363                 snprintf(error_sock_path, PATH_MAX,
 364                                 KCONSUMERD_ERR_SOCK_PATH);
 365         }
 366
 367         if (set_signal_handler() < 0) {
 368                 goto error;
 369         }
 370
 371         /* Connect to the socket created by ltt-sessiond to report errors */
 372         DBG("Connecting to error socket %s", error_sock_path);
 373         ret = lttcomm_connect_unix_sock(error_sock_path);
 374         /* not a fatal error, but all communication with ltt-sessiond will fail */
 375         if (ret < 0) {
 376                 WARN("Cannot connect to error socket, is ltt-sessiond started ?");
 377         }
 378         lttng_kconsumerd_set_error_sock(ctx, ret);
 379
 380         /* Create the thread to manage the receive of fd */
 381         ret = pthread_create(&threads[0], NULL, lttng_kconsumerd_thread_receive_fds,
 382                         (void *) ctx);
 383         if (ret != 0) {
 384                 perror("pthread_create");
 385                 goto error;
 386         }
 387
 388         /* Create thread to manage the polling/writing of traces */
 389         ret = pthread_create(&threads[1], NULL, lttng_kconsumerd_thread_poll_fds,
 390                         (void *) ctx);
 391         if (ret != 0) {
 392                 perror("pthread_create");
 393                 goto error;
 394         }
 395
 396         for (i = 0; i < 2; i++) {
 397                 ret = pthread_join(threads[i], &status);
 398                 if (ret != 0) {
 399                         perror("pthread_join");
 400                         goto error;
 401                 }
 402         }
 403         ret = EXIT_SUCCESS;
 404         lttng_kconsumerd_send_error(ctx, KCONSUMERD_EXIT_SUCCESS);
 405         goto end;
 406
 407 error:
 408         ret = EXIT_FAILURE;
 409         lttng_kconsumerd_send_error(ctx, KCONSUMERD_EXIT_FAILURE);
 410
 411 end:
 412         lttng_kconsumerd_destroy(ctx);
 413         lttng_kconsumerd_cleanup();
 414
 415         return ret;
 416 }