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 "lttngerr.h"
  41 #include "kernelctl.h"
  42 #include "lttkconsumerd.h"
  43
  44 /* the two threads (receive fd and poll) */
  45 pthread_t threads[2];
  46
  47 /* to count the number of time the user pressed ctrl+c */
  48 static int sigintcount = 0;
  49
  50 /* Argument variables */
  51 int opt_quiet;
  52 int opt_verbose;
  53 static int opt_daemon;
  54 static const char *progname;
  55 char command_sock_path[PATH_MAX]; /* Global command socket path */
  56 char error_sock_path[PATH_MAX]; /* Global error path */
  57
  58 /* the liblttkconsumerd context */
  59 struct kconsumerd_local_data *ctx;
  60
  61 /*
  62  *  sighandler
  63  *
  64  *  Signal handler for the daemon
  65  */
  66 static void sighandler(int sig)
  67 {
  68         if (sig == SIGINT && sigintcount++ == 0) {
  69                 DBG("ignoring first SIGINT");
  70                 return;
  71         }
  72
  73         kconsumerd_should_exit(ctx);
  74 }
  75
  76 /*
  77  *  set_signal_handler
  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  * read_subbuffer
 198  *
 199  * Consume data on a file descriptor and write it on a trace file
 200  */
 201 static int read_subbuffer(struct kconsumerd_fd *kconsumerd_fd)
 202 {
 203         unsigned long len;
 204         int err;
 205         long ret = 0;
 206         int infd = kconsumerd_fd->consumerd_fd;
 207
 208         DBG("In kconsumerd_read_subbuffer (infd : %d)", infd);
 209         /* Get the next subbuffer */
 210         err = kernctl_get_next_subbuf(infd);
 211         if (err != 0) {
 212                 ret = errno;
 213                 perror("Reserving sub buffer failed (everything is normal, "
 214                                 "it is due to concurrency)");
 215                 goto end;
 216         }
 217
 218         switch (kconsumerd_fd->output) {
 219                 case LTTNG_EVENT_SPLICE:
 220                         /* read the whole subbuffer */
 221                         err = kernctl_get_padded_subbuf_size(infd, &len);
 222                         if (err != 0) {
 223                                 ret = errno;
 224                                 perror("Getting sub-buffer len failed.");
 225                                 goto end;
 226                         }
 227
 228                         /* splice the subbuffer to the tracefile */
 229                         ret = kconsumerd_on_read_subbuffer_splice(ctx, kconsumerd_fd, len);
 230                         if (ret < 0) {
 231                                 /*
 232                                  * display the error but continue processing to try
 233                                  * to release the subbuffer
 234                                  */
 235                                 ERR("Error splicing to tracefile");
 236                         }
 237                         break;
 238                 case LTTNG_EVENT_MMAP:
 239                         /* read the used subbuffer size */
 240                         err = kernctl_get_padded_subbuf_size(infd, &len);
 241                         if (err != 0) {
 242                                 ret = errno;
 243                                 perror("Getting sub-buffer len failed.");
 244                                 goto end;
 245                         }
 246                         /* write the subbuffer to the tracefile */
 247                         ret = kconsumerd_on_read_subbuffer_mmap(ctx, kconsumerd_fd, len);
 248                         if (ret < 0) {
 249                                 /*
 250                                  * display the error but continue processing to try
 251                                  * to release the subbuffer
 252                                  */
 253                                 ERR("Error writing to tracefile");
 254                         }
 255                         break;
 256                 default:
 257                         ERR("Unknown output method");
 258                         ret = -1;
 259         }
 260
 261         err = kernctl_put_next_subbuf(infd);
 262         if (err != 0) {
 263                 ret = errno;
 264                 if (errno == EFAULT) {
 265                         perror("Error in unreserving sub buffer\n");
 266                 } else if (errno == EIO) {
 267                         /* Should never happen with newer LTTng versions */
 268                         perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
 269                 }
 270                 goto end;
 271         }
 272
 273 end:
 274         return ret;
 275 }
 276
 277 /*
 278  * main
 279  */
 280 int main(int argc, char **argv)
 281 {
 282         int i;
 283         int ret = 0;
 284         void *status;
 285
 286         /* Parse arguments */
 287         progname = argv[0];
 288         parse_args(argc, argv);
 289
 290         /* Daemonize */
 291         if (opt_daemon) {
 292                 ret = daemon(0, 0);
 293                 if (ret < 0) {
 294                         perror("daemon");
 295                         goto error;
 296                 }
 297         }
 298
 299         if (strlen(command_sock_path) == 0) {
 300                 snprintf(command_sock_path, PATH_MAX,
 301                                 KCONSUMERD_CMD_SOCK_PATH);
 302         }
 303         /* create the pipe to wake to receiving thread when needed */
 304         ctx = kconsumerd_create(read_subbuffer);
 305         if (ctx == NULL) {
 306                 goto error;
 307         }
 308
 309         kconsumerd_set_command_socket_path(ctx, command_sock_path);
 310         if (strlen(error_sock_path) == 0) {
 311                 snprintf(error_sock_path, PATH_MAX,
 312                                 KCONSUMERD_ERR_SOCK_PATH);
 313         }
 314
 315         if (set_signal_handler() < 0) {
 316                 goto error;
 317         }
 318
 319         /* Connect to the socket created by ltt-sessiond to report errors */
 320         DBG("Connecting to error socket %s", error_sock_path);
 321         ret = lttcomm_connect_unix_sock(error_sock_path);
 322         /* not a fatal error, but all communication with ltt-sessiond will fail */
 323         if (ret < 0) {
 324                 WARN("Cannot connect to error socket, is ltt-sessiond started ?");
 325         }
 326         kconsumerd_set_error_socket(ctx, ret);
 327
 328         /* Create the thread to manage the receive of fd */
 329         ret = pthread_create(&threads[0], NULL, kconsumerd_thread_receive_fds,
 330                         (void *) ctx);
 331         if (ret != 0) {
 332                 perror("pthread_create");
 333                 goto error;
 334         }
 335
 336         /* Create thread to manage the polling/writing of traces */
 337         ret = pthread_create(&threads[1], NULL, kconsumerd_thread_poll_fds,
 338                         (void *) ctx);
 339         if (ret != 0) {
 340                 perror("pthread_create");
 341                 goto error;
 342         }
 343
 344         for (i = 0; i < 2; i++) {
 345                 ret = pthread_join(threads[i], &status);
 346                 if (ret != 0) {
 347                         perror("pthread_join");
 348                         goto error;
 349                 }
 350         }
 351         ret = EXIT_SUCCESS;
 352         kconsumerd_send_error(ctx, KCONSUMERD_EXIT_SUCCESS);
 353         goto end;
 354
 355 error:
 356         ret = EXIT_FAILURE;
 357         kconsumerd_send_error(ctx, KCONSUMERD_EXIT_FAILURE);
 358
 359 end:
 360         kconsumerd_destroy(ctx);
 361         kconsumerd_cleanup();
 362
 363         return ret;
 364 }