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