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
  40 #include <lttng/lttng-kconsumerd.h>
  41
  42 #include "lttngerr.h"
  43 #include "kernelctl.h"
  44 #include "ltt-kconsumerd.h"
  45 #include "lttng-sessiond-comm.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                 perror("Reserving sub buffer failed (everything is normal, "
 211                                 "it is due to concurrency)");
 212                 goto end;
 213         }
 214
 215         switch (kconsumerd_fd->output) {
 216                 case LTTNG_EVENT_SPLICE:
 217                         /* read the whole subbuffer */
 218                         err = kernctl_get_padded_subbuf_size(infd, &len);
 219                         if (err != 0) {
 220                                 ret = errno;
 221                                 perror("Getting sub-buffer len failed.");
 222                                 goto end;
 223                         }
 224
 225                         /* splice the subbuffer to the tracefile */
 226                         ret = lttng_kconsumerd_on_read_subbuffer_splice(ctx, kconsumerd_fd, len);
 227                         if (ret < 0) {
 228                                 /*
 229                                  * display the error but continue processing to try
 230                                  * to release the subbuffer
 231                                  */
 232                                 ERR("Error splicing to tracefile");
 233                         }
 234                         break;
 235                 case LTTNG_EVENT_MMAP:
 236                         /* read the used subbuffer size */
 237                         err = kernctl_get_padded_subbuf_size(infd, &len);
 238                         if (err != 0) {
 239                                 ret = errno;
 240                                 perror("Getting sub-buffer len failed.");
 241                                 goto end;
 242                         }
 243                         /* write the subbuffer to the tracefile */
 244                         ret = lttng_kconsumerd_on_read_subbuffer_mmap(ctx, kconsumerd_fd, len);
 245                         if (ret < 0) {
 246                                 /*
 247                                  * display the error but continue processing to try
 248                                  * to release the subbuffer
 249                                  */
 250                                 ERR("Error writing to tracefile");
 251                         }
 252                         break;
 253                 default:
 254                         ERR("Unknown output method");
 255                         ret = -1;
 256         }
 257
 258         err = kernctl_put_next_subbuf(infd);
 259         if (err != 0) {
 260                 ret = errno;
 261                 if (errno == EFAULT) {
 262                         perror("Error in unreserving sub buffer\n");
 263                 } else if (errno == EIO) {
 264                         /* Should never happen with newer LTTng versions */
 265                         perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
 266                 }
 267                 goto end;
 268         }
 269
 270 end:
 271         return ret;
 272 }
 273
 274 /*
 275  * main
 276  */
 277 int main(int argc, char **argv)
 278 {
 279         int i;
 280         int ret = 0;
 281         void *status;
 282
 283         /* Parse arguments */
 284         progname = argv[0];
 285         parse_args(argc, argv);
 286
 287         /* Daemonize */
 288         if (opt_daemon) {
 289                 ret = daemon(0, 0);
 290                 if (ret < 0) {
 291                         perror("daemon");
 292                         goto error;
 293                 }
 294         }
 295
 296         if (strlen(command_sock_path) == 0) {
 297                 snprintf(command_sock_path, PATH_MAX,
 298                                 KCONSUMERD_CMD_SOCK_PATH);
 299         }
 300         /* create the pipe to wake to receiving thread when needed */
 301         ctx = lttng_kconsumerd_create(read_subbuffer);
 302         if (ctx == NULL) {
 303                 goto error;
 304         }
 305
 306         lttng_kconsumerd_set_command_sock_path(ctx, command_sock_path);
 307         if (strlen(error_sock_path) == 0) {
 308                 snprintf(error_sock_path, PATH_MAX,
 309                                 KCONSUMERD_ERR_SOCK_PATH);
 310         }
 311
 312         if (set_signal_handler() < 0) {
 313                 goto error;
 314         }
 315
 316         /* Connect to the socket created by ltt-sessiond to report errors */
 317         DBG("Connecting to error socket %s", error_sock_path);
 318         ret = lttcomm_connect_unix_sock(error_sock_path);
 319         /* not a fatal error, but all communication with ltt-sessiond will fail */
 320         if (ret < 0) {
 321                 WARN("Cannot connect to error socket, is ltt-sessiond started ?");
 322         }
 323         lttng_kconsumerd_set_error_sock(ctx, ret);
 324
 325         /* Create the thread to manage the receive of fd */
 326         ret = pthread_create(&threads[0], NULL, lttng_kconsumerd_thread_receive_fds,
 327                         (void *) ctx);
 328         if (ret != 0) {
 329                 perror("pthread_create");
 330                 goto error;
 331         }
 332
 333         /* Create thread to manage the polling/writing of traces */
 334         ret = pthread_create(&threads[1], NULL, lttng_kconsumerd_thread_poll_fds,
 335                         (void *) ctx);
 336         if (ret != 0) {
 337                 perror("pthread_create");
 338                 goto error;
 339         }
 340
 341         for (i = 0; i < 2; i++) {
 342                 ret = pthread_join(threads[i], &status);
 343                 if (ret != 0) {
 344                         perror("pthread_join");
 345                         goto error;
 346                 }
 347         }
 348         ret = EXIT_SUCCESS;
 349         lttng_kconsumerd_send_error(ctx, KCONSUMERD_EXIT_SUCCESS);
 350         goto end;
 351
 352 error:
 353         ret = EXIT_FAILURE;
 354         lttng_kconsumerd_send_error(ctx, KCONSUMERD_EXIT_FAILURE);
 355
 356 end:
 357         lttng_kconsumerd_destroy(ctx);
 358         lttng_kconsumerd_cleanup();
 359
 360         return ret;
 361 }