src/bin/lttng/lttng.c

   1 /*
   2  * Copyright (c)  2011 David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * as published by the Free Software Foundation; only version 2
   7  * of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <getopt.h>
  21 #include <signal.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <config.h>
  27
  28 #include <lttng/lttng.h>
  29 #include <common/lttngerr.h>
  30
  31 #include "command.h"
  32
  33 /* Variables */
  34 static char *progname;
  35
  36 int opt_quiet;
  37 int opt_verbose;
  38 static int opt_no_sessiond;
  39 static char *opt_sessiond_path;
  40
  41 enum {
  42         OPT_SESSION_PATH,
  43         OPT_DUMP_OPTIONS,
  44         OPT_DUMP_COMMANDS,
  45 };
  46
  47 /* Getopt options. No first level command. */
  48 static struct option long_options[] = {
  49         {"help",             0, NULL, 'h'},
  50         {"group",            1, NULL, 'g'},
  51         {"verbose",          0, NULL, 'v'},
  52         {"quiet",            0, NULL, 'q'},
  53         {"no-sessiond",      0, NULL, 'n'},
  54         {"sessiond-path",    1, NULL, OPT_SESSION_PATH},
  55         {"list-options",     0, NULL, OPT_DUMP_OPTIONS},
  56         {"list-commands",    0, NULL, OPT_DUMP_COMMANDS},
  57         {NULL, 0, NULL, 0}
  58 };
  59
  60 /* First level command */
  61 static struct cmd_struct commands[] =  {
  62         { "list", cmd_list},
  63         { "create", cmd_create},
  64         { "destroy", cmd_destroy},
  65         { "start", cmd_start},
  66         { "stop", cmd_stop},
  67         { "enable-event", cmd_enable_events},
  68         { "disable-event", cmd_disable_events},
  69         { "enable-channel", cmd_enable_channels},
  70         { "disable-channel", cmd_disable_channels},
  71         { "add-context", cmd_add_context},
  72         { "set-session", cmd_set_session},
  73         { "version", cmd_version},
  74         { "calibrate", cmd_calibrate},
  75         { NULL, NULL}   /* Array closure */
  76 };
  77
  78 static void usage(FILE *ofp)
  79 {
  80         fprintf(ofp, "LTTng Trace Control " VERSION"\n\n");
  81         fprintf(ofp, "usage: lttng [options] <command>\n");
  82         fprintf(ofp, "\n");
  83         fprintf(ofp, "Options:\n");
  84         fprintf(ofp, "  -h, --help             Show this help\n");
  85         fprintf(ofp, "  -g, --group NAME       Unix tracing group name. (default: tracing)\n");
  86         fprintf(ofp, "  -v, --verbose          Verbose mode\n");
  87         fprintf(ofp, "  -q, --quiet            Quiet mode\n");
  88         fprintf(ofp, "  -n, --no-sessiond      Don't spawn a session daemon\n");
  89         fprintf(ofp, "      --sessiond-path    Session daemon full path\n");
  90         fprintf(ofp, "      --list-options     Simple listing of lttng options\n");
  91         fprintf(ofp, "      --list-commands    Simple listing of lttng commands\n");
  92         fprintf(ofp, "\n");
  93         fprintf(ofp, "Commands:\n");
  94         fprintf(ofp, "    add-context     Add context to event or/and channel\n");
  95         fprintf(ofp, "    calibrate       Quantify LTTng overhead\n");
  96         fprintf(ofp, "    create          Create tracing session\n");
  97         fprintf(ofp, "    destroy         Teardown tracing session\n");
  98         fprintf(ofp, "    enable-channel  Enable tracing channel\n");
  99         fprintf(ofp, "    enable-event    Enable tracing event\n");
 100         fprintf(ofp, "    disable-channel Disable tracing channel\n");
 101         fprintf(ofp, "    disable-event   Disable tracing event\n");
 102         fprintf(ofp, "    list            List possible tracing options\n");
 103         fprintf(ofp, "    set-session     Set current session name\n");
 104         fprintf(ofp, "    start           Start tracing\n");
 105         fprintf(ofp, "    stop            Stop tracing\n");
 106         fprintf(ofp, "    version         Show version information\n");
 107         fprintf(ofp, "\n");
 108         fprintf(ofp, "Please see the lttng(1) man page for full documentation.\n");
 109         fprintf(ofp, "See http://lttng.org for updates, bug reports and news.\n");
 110 }
 111
 112 /*
 113  *  list_options
 114  *
 115  *  List options line by line. This is mostly for bash auto completion and to
 116  *  avoid difficult parsing.
 117  */
 118 static void list_options(FILE *ofp)
 119 {
 120         int i = 0;
 121         struct option *option = NULL;
 122
 123         option = &long_options[i];
 124         while (option->name != NULL) {
 125                 fprintf(ofp, "--%s\n", option->name);
 126
 127                 if (isprint(option->val)) {
 128                         fprintf(ofp, "-%c\n", option->val);
 129                 }
 130
 131                 i++;
 132                 option = &long_options[i];
 133         }
 134 }
 135
 136 /*
 137  *  list_commands
 138  *
 139  *  List commands line by line. This is mostly for bash auto completion and to
 140  *  avoid difficult parsing.
 141  */
 142 static void list_commands(FILE *ofp)
 143 {
 144         int i = 0;
 145         struct cmd_struct *cmd = NULL;
 146
 147         cmd = &commands[i];
 148         while (cmd->name != NULL) {
 149                 fprintf(ofp, "%s\n", cmd->name);
 150                 i++;
 151                 cmd = &commands[i];
 152         }
 153 }
 154
 155 /*
 156  * clean_exit
 157  */
 158 static void clean_exit(int code)
 159 {
 160         DBG("Clean exit");
 161         exit(code);
 162 }
 163
 164 /*
 165  *  sighandler
 166  *
 167  *  Signal handler for the daemon
 168  */
 169 static void sighandler(int sig)
 170 {
 171         switch (sig) {
 172                 case SIGTERM:
 173                         DBG("SIGTERM caugth");
 174                         clean_exit(EXIT_FAILURE);
 175                         break;
 176                 case SIGCHLD:
 177                         /* Notify is done */
 178                         DBG("SIGCHLD caugth");
 179                         break;
 180                 default:
 181                         DBG("Unknown signal %d caugth", sig);
 182                         break;
 183         }
 184
 185         return;
 186 }
 187
 188 /*
 189  *  set_signal_handler
 190  *
 191  *  Setup signal handler for SIGCHLD and SIGTERM.
 192  */
 193 static int set_signal_handler(void)
 194 {
 195         int ret = 0;
 196         struct sigaction sa;
 197         sigset_t sigset;
 198
 199         if ((ret = sigemptyset(&sigset)) < 0) {
 200                 perror("sigemptyset");
 201                 goto end;
 202         }
 203
 204         sa.sa_handler = sighandler;
 205         sa.sa_mask = sigset;
 206         sa.sa_flags = 0;
 207         if ((ret = sigaction(SIGCHLD, &sa, NULL)) < 0) {
 208                 perror("sigaction");
 209                 goto end;
 210         }
 211
 212         if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
 213                 perror("sigaction");
 214                 goto end;
 215         }
 216
 217 end:
 218         return ret;
 219 }
 220
 221 /*
 222  *  handle_command
 223  *
 224  *  Handle the full argv list of a first level command. Will find the command
 225  *  in the global commands array and call the function callback associated.
 226  *
 227  *  If command not found, return -1
 228  *  else, return function command error code.
 229  */
 230 static int handle_command(int argc, char **argv)
 231 {
 232         int i = 0, ret;
 233         struct cmd_struct *cmd;
 234
 235         if (*argv == NULL) {
 236                 ret = CMD_SUCCESS;
 237                 goto end;
 238         }
 239
 240         cmd = &commands[i];
 241         while (cmd->func != NULL) {
 242                 /* Find command */
 243                 if (strcmp(argv[0], cmd->name) == 0) {
 244                         ret = cmd->func(argc, (const char**) argv);
 245                         switch (ret) {
 246                         case CMD_ERROR:
 247                                 ERR("Command error");
 248                                 break;
 249                         case CMD_NOT_IMPLEMENTED:
 250                                 ERR("Options not implemented");
 251                                 break;
 252                         case CMD_UNDEFINED:
 253                                 ERR("Undefined command");
 254                                 break;
 255                         case CMD_FATAL:
 256                                 ERR("Fatal error");
 257                                 break;
 258                         }
 259                         goto end;
 260                 }
 261                 i++;
 262                 cmd = &commands[i];
 263         }
 264
 265         /* Command not found */
 266         ret = -1;
 267
 268 end:
 269         return ret;
 270 }
 271
 272 /*
 273  *  spawn_sessiond
 274  *
 275  *  Spawn a session daemon by forking and execv.
 276  */
 277 static int spawn_sessiond(char *pathname)
 278 {
 279         int ret = 0;
 280         pid_t pid;
 281
 282         MSG("Spawning a session daemon");
 283         pid = fork();
 284         if (pid == 0) {
 285                 /*
 286                  * Spawn session daemon and tell
 287                  * it to signal us when ready.
 288                  */
 289                 execlp(pathname, "lttng-sessiond", "--sig-parent", "--quiet", NULL);
 290                 /* execlp only returns if error happened */
 291                 if (errno == ENOENT) {
 292                         ERR("No session daemon found. Use --sessiond-path.");
 293                 } else {
 294                         perror("execlp");
 295                 }
 296                 kill(getppid(), SIGTERM);       /* unpause parent */
 297                 exit(EXIT_FAILURE);
 298         } else if (pid > 0) {
 299                 /* Wait for lttng-sessiond to start */
 300                 pause();
 301                 goto end;
 302         } else {
 303                 perror("fork");
 304                 ret = -1;
 305                 goto end;
 306         }
 307
 308 end:
 309         return ret;
 310 }
 311
 312 /*
 313  *  check_sessiond
 314  *
 315  *  Check if the session daemon is available using
 316  *  the liblttngctl API for the check. If not, try to
 317  *  spawn a daemon.
 318  */
 319 static int check_sessiond(void)
 320 {
 321         int ret;
 322         char *pathname = NULL, *alloc_pathname = NULL;
 323
 324         ret = lttng_session_daemon_alive();
 325         if (ret == 0) { /* not alive */
 326                 /* Try command line option path */
 327                 if (opt_sessiond_path != NULL) {
 328                         ret = access(opt_sessiond_path, F_OK | X_OK);
 329                         if (ret < 0) {
 330                                 ERR("No such file: %s", opt_sessiond_path);
 331                                 goto end;
 332                         }
 333                         pathname = opt_sessiond_path;
 334                 } else {
 335                         /* Try LTTNG_SESSIOND_PATH env variable */
 336                         pathname = getenv(LTTNG_SESSIOND_PATH_ENV);
 337                 }
 338
 339                 /* Let's rock and roll */
 340                 if (pathname == NULL) {
 341                         ret = asprintf(&alloc_pathname, INSTALL_BIN_PATH "/lttng-sessiond");
 342                         if (ret < 0) {
 343                                 perror("asprintf spawn sessiond");
 344                                 goto end;
 345                         }
 346                         pathname = alloc_pathname;
 347                 }
 348
 349                 ret = spawn_sessiond(pathname);
 350                 free(alloc_pathname);
 351                 if (ret < 0) {
 352                         ERR("Problem occurs when starting %s", pathname);
 353                         goto end;
 354                 }
 355         }
 356
 357 end:
 358         return ret;
 359 }
 360
 361 /*
 362  * Check for the "help" option in the argv. If found, return 1 else return 0.
 363  */
 364 static int check_help_command(int argc, char **argv)
 365 {
 366         int i;
 367
 368         for (i = 0; i < argc; i++) {
 369                 if ((strncmp(argv[i], "-h", 2) == 0) ||
 370                                 strncmp(argv[i], "--h", 3) == 0) {
 371                         return 1;
 372                 }
 373         }
 374
 375         return 0;
 376 }
 377
 378 /*
 379  *  parse_args
 380  *
 381  *  Parse command line arguments.
 382  *  Return 0 if OK, else -1
 383  */
 384 static int parse_args(int argc, char **argv)
 385 {
 386         int opt, ret;
 387
 388         if (argc < 2) {
 389                 usage(stderr);
 390                 clean_exit(EXIT_FAILURE);
 391         }
 392
 393         while ((opt = getopt_long(argc, argv, "+hnvqg:", long_options, NULL)) != -1) {
 394                 switch (opt) {
 395                 case 'h':
 396                         usage(stderr);
 397                         goto error;
 398                 case 'v':
 399                         opt_verbose += 1;
 400                         break;
 401                 case 'q':
 402                         opt_quiet = 1;
 403                         break;
 404                 case 'g':
 405                         lttng_set_tracing_group(optarg);
 406                         break;
 407                 case 'n':
 408                         opt_no_sessiond = 1;
 409                         break;
 410                 case OPT_SESSION_PATH:
 411                         opt_sessiond_path = strdup(optarg);
 412                         break;
 413                 case OPT_DUMP_OPTIONS:
 414                         list_options(stdout);
 415                         ret = 0;
 416                         goto error;
 417                 case OPT_DUMP_COMMANDS:
 418                         list_commands(stdout);
 419                         ret = 0;
 420                         goto error;
 421                 default:
 422                         usage(stderr);
 423                         goto error;
 424                 }
 425         }
 426
 427         /* If both options are specified, quiet wins */
 428         if (opt_verbose && opt_quiet) {
 429                 opt_verbose = 0;
 430         }
 431
 432         /* Spawn session daemon if needed */
 433         if (opt_no_sessiond == 0 && check_help_command(argc, argv) == 0 &&
 434                         (check_sessiond() < 0)) {
 435                 goto error;
 436         }
 437
 438         /* No leftovers, print usage and quit */
 439         if ((argc - optind) == 0) {
 440                 usage(stderr);
 441                 goto error;
 442         }
 443
 444         /*
 445          * Handle leftovers which is a first level command with the trailing
 446          * options.
 447          */
 448         ret = handle_command(argc - optind, argv + optind);
 449         if (ret < 0) {
 450                 if (ret == -1) {
 451                         usage(stderr);
 452                 } else {
 453                         ERR("%s", lttng_strerror(ret));
 454                 }
 455                 goto error;
 456         }
 457
 458         return 0;
 459
 460 error:
 461         return -1;
 462 }
 463
 464
 465 /*
 466  *  main
 467  */
 468 int main(int argc, char *argv[])
 469 {
 470         int ret;
 471
 472         progname = argv[0] ? argv[0] : "lttng";
 473
 474         /* For Mathieu Desnoyers aka Dr Tracing */
 475         if (strncmp(progname, "drtrace", 7) == 0) {
 476                 MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n\n", 27,1,33,27,0);
 477         }
 478
 479         ret = set_signal_handler();
 480         if (ret < 0) {
 481                 clean_exit(ret);
 482         }
 483
 484         ret = parse_args(argc, argv);
 485         if (ret < 0) {
 486                 clean_exit(EXIT_FAILURE);
 487         }
 488
 489         return 0;
 490 }