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, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #define _LGPL_SOURCE
  20 #include <getopt.h>
  21 #include <signal.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/types.h>
  26 #include <sys/wait.h>
  27 #include <unistd.h>
  28 #include <config.h>
  29 #include <ctype.h>
  30
  31 #include <lttng/lttng.h>
  32 #include <common/error.h>
  33 #include <common/compat/getenv.h>
  34
  35 #include "command.h"
  36
  37 /* Variables */
  38 static char *progname;
  39 static int opt_no_sessiond;
  40 static char *opt_sessiond_path;
  41 static pid_t sessiond_pid;
  42 static volatile int recv_child_signal;
  43
  44 char *opt_relayd_path;
  45
  46 enum {
  47         OPT_RELAYD_PATH,
  48         OPT_SESSION_PATH,
  49         OPT_DUMP_OPTIONS,
  50         OPT_DUMP_COMMANDS,
  51 };
  52
  53 /* Getopt options. No first level command. */
  54 static struct option long_options[] = {
  55         {"version",          0, NULL, 'V'},
  56         {"help",             0, NULL, 'h'},
  57         {"group",            1, NULL, 'g'},
  58         {"verbose",          0, NULL, 'v'},
  59         {"quiet",            0, NULL, 'q'},
  60         {"mi",               1, NULL, 'm'},
  61         {"no-sessiond",      0, NULL, 'n'},
  62         {"sessiond-path",    1, NULL, OPT_SESSION_PATH},
  63         {"relayd-path",      1, NULL, OPT_RELAYD_PATH},
  64         {"list-options",     0, NULL, OPT_DUMP_OPTIONS},
  65         {"list-commands",    0, NULL, OPT_DUMP_COMMANDS},
  66         {NULL, 0, NULL, 0}
  67 };
  68
  69 /* First level command */
  70 static struct cmd_struct commands[] =  {
  71         { "list", cmd_list},
  72         { "create", cmd_create},
  73         { "destroy", cmd_destroy},
  74         { "start", cmd_start},
  75         { "stop", cmd_stop},
  76         { "enable-event", cmd_enable_events},
  77         { "disable-event", cmd_disable_events},
  78         { "enable-channel", cmd_enable_channels},
  79         { "disable-channel", cmd_disable_channels},
  80         { "add-context", cmd_add_context},
  81         { "set-session", cmd_set_session},
  82         { "version", cmd_version},
  83         { "calibrate", cmd_calibrate},
  84         { "view", cmd_view},
  85         { "snapshot", cmd_snapshot},
  86         { "save", cmd_save},
  87         { "load", cmd_load},
  88         { "track", cmd_track},
  89         { "untrack", cmd_untrack},
  90         { NULL, NULL}   /* Array closure */
  91 };
  92
  93 static void usage(FILE *ofp)
  94 {
  95         fprintf(ofp, "LTTng Trace Control " VERSION " - " VERSION_NAME "%s\n\n",
  96                 GIT_VERSION[0] == '\0' ? "" : " - " GIT_VERSION);
  97         fprintf(ofp, "usage: lttng [OPTIONS] <COMMAND> [<ARGS>]\n");
  98         fprintf(ofp, "\n");
  99         fprintf(ofp, "Options:\n");
 100         fprintf(ofp, "  -V, --version              Show version\n");
 101         fprintf(ofp, "  -h, --help                 Show this help\n");
 102         fprintf(ofp, "      --list-options         Simple listing of lttng options\n");
 103         fprintf(ofp, "      --list-commands        Simple listing of lttng commands\n");
 104         fprintf(ofp, "  -v, --verbose              Increase verbosity\n");
 105         fprintf(ofp, "  -q, --quiet                Quiet mode\n");
 106         fprintf(ofp, "  -m, --mi TYPE              Machine Interface mode.\n");
 107         fprintf(ofp, "                                 Type: xml\n");
 108         fprintf(ofp, "  -g, --group NAME           Unix tracing group name. (default: tracing)\n");
 109         fprintf(ofp, "  -n, --no-sessiond          Don't spawn a session daemon\n");
 110         fprintf(ofp, "      --sessiond-path PATH   Session daemon full path\n");
 111         fprintf(ofp, "      --relayd-path PATH     Relayd daemon full path\n");
 112         fprintf(ofp, "\n");
 113         fprintf(ofp, "Commands:\n");
 114         fprintf(ofp, "    add-context       Add context to event and/or channel\n");
 115         fprintf(ofp, "    calibrate         Quantify LTTng overhead\n");
 116         fprintf(ofp, "    create            Create tracing session\n");
 117         fprintf(ofp, "    destroy           Tear down tracing session\n");
 118         fprintf(ofp, "    enable-channel    Enable tracing channel\n");
 119         fprintf(ofp, "    enable-event      Enable tracing event\n");
 120         fprintf(ofp, "    disable-channel   Disable tracing channel\n");
 121         fprintf(ofp, "    disable-event     Disable tracing event\n");
 122         fprintf(ofp, "    list              List possible tracing options\n");
 123         fprintf(ofp, "    set-session       Set current session name\n");
 124         fprintf(ofp, "    snapshot          Snapshot buffers of current session name\n");
 125         fprintf(ofp, "    start             Start tracing\n");
 126         fprintf(ofp, "    stop              Stop tracing\n");
 127         fprintf(ofp, "    version           Show version information\n");
 128         fprintf(ofp, "    view              Start trace viewer\n");
 129         fprintf(ofp, "    save              Save session configuration\n");
 130         fprintf(ofp, "    load              Load session configuration\n");
 131         fprintf(ofp, "    track             Track specific system resources\n");
 132         fprintf(ofp, "    untrack           Untrack specific system resources\n");
 133         fprintf(ofp, "\n");
 134         fprintf(ofp, "Each command also has its own -h, --help option.\n");
 135         fprintf(ofp, "\n");
 136         fprintf(ofp, "Please see the lttng(1) man page for full documentation.\n");
 137         fprintf(ofp, "See http://lttng.org for updates, bug reports and news.\n");
 138 }
 139
 140 static void version(FILE *ofp)
 141 {
 142         fprintf(ofp, "%s (LTTng Trace Control) " VERSION" - " VERSION_NAME "%s\n",
 143                         progname,
 144                         GIT_VERSION[0] == '\0' ? "" : " - " GIT_VERSION);
 145 }
 146
 147 /*
 148  * Find the MI output type enum from a string. This function is for the support
 149  * of machine interface output.
 150  */
 151 static int mi_output_type(const char *output_type)
 152 {
 153         int ret = 0;
 154
 155         if (!strncasecmp("xml", output_type, 3)) {
 156                 ret = LTTNG_MI_XML;
 157         } else {
 158                 /* Invalid output format */
 159                 ERR("MI output format not supported");
 160                 ret = -LTTNG_ERR_MI_OUTPUT_TYPE;
 161         }
 162
 163         return ret;
 164 }
 165
 166 /*
 167  *  list_options
 168  *
 169  *  List options line by line. This is mostly for bash auto completion and to
 170  *  avoid difficult parsing.
 171  */
 172 static void list_options(FILE *ofp)
 173 {
 174         int i = 0;
 175         struct option *option = NULL;
 176
 177         option = &long_options[i];
 178         while (option->name != NULL) {
 179                 fprintf(ofp, "--%s\n", option->name);
 180
 181                 if (isprint(option->val)) {
 182                         fprintf(ofp, "-%c\n", option->val);
 183                 }
 184
 185                 i++;
 186                 option = &long_options[i];
 187         }
 188 }
 189
 190 /*
 191  * clean_exit
 192  */
 193 static void clean_exit(int code)
 194 {
 195         DBG("Clean exit");
 196         exit(code);
 197 }
 198
 199 /*
 200  *  sighandler
 201  *
 202  *  Signal handler for the daemon
 203  */
 204 static void sighandler(int sig)
 205 {
 206         int status;
 207
 208         switch (sig) {
 209                 case SIGTERM:
 210                         DBG("SIGTERM caught");
 211                         clean_exit(EXIT_FAILURE);
 212                         break;
 213                 case SIGCHLD:
 214                         DBG("SIGCHLD caught");
 215                         waitpid(sessiond_pid, &status, 0);
 216                         recv_child_signal = 1;
 217                         /* Indicate that the session daemon died */
 218                         sessiond_pid = 0;
 219                         ERR("Session daemon died (exit status %d)", WEXITSTATUS(status));
 220                         break;
 221                 case SIGUSR1:
 222                         /* Notify is done */
 223                         recv_child_signal = 1;
 224                         DBG("SIGUSR1 caught");
 225                         break;
 226                 default:
 227                         DBG("Unknown signal %d caught", sig);
 228                         break;
 229         }
 230
 231         return;
 232 }
 233
 234 /*
 235  *  set_signal_handler
 236  *
 237  *  Setup signal handler for SIGCHLD and SIGTERM.
 238  */
 239 static int set_signal_handler(void)
 240 {
 241         int ret = 0;
 242         struct sigaction sa;
 243         sigset_t sigset;
 244
 245         if ((ret = sigemptyset(&sigset)) < 0) {
 246                 PERROR("sigemptyset");
 247                 goto end;
 248         }
 249
 250         sa.sa_handler = sighandler;
 251         sa.sa_mask = sigset;
 252         sa.sa_flags = 0;
 253         if ((ret = sigaction(SIGUSR1, &sa, NULL)) < 0) {
 254                 PERROR("sigaction");
 255                 goto end;
 256         }
 257
 258         if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
 259                 PERROR("sigaction");
 260                 goto end;
 261         }
 262
 263         if ((ret = sigaction(SIGCHLD, &sa, NULL)) < 0) {
 264                 PERROR("sigaction");
 265                 goto end;
 266         }
 267
 268 end:
 269         return ret;
 270 }
 271
 272 /*
 273  *  handle_command
 274  *
 275  *  Handle the full argv list of a first level command. Will find the command
 276  *  in the global commands array and call the function callback associated.
 277  *
 278  *  If command not found, return -1
 279  *  else, return function command error code.
 280  */
 281 static int handle_command(int argc, char **argv)
 282 {
 283         int i = 0, ret;
 284         struct cmd_struct *cmd;
 285
 286         if (*argv == NULL) {
 287                 ret = CMD_SUCCESS;
 288                 goto end;
 289         }
 290
 291         cmd = &commands[i];
 292         while (cmd->func != NULL) {
 293                 /* Find command */
 294                 if (strcmp(argv[0], cmd->name) == 0) {
 295                         ret = cmd->func(argc, (const char**) argv);
 296                         goto end;
 297                 }
 298                 i++;
 299                 cmd = &commands[i];
 300         }
 301
 302         /* Command not found */
 303         ret = CMD_UNDEFINED;
 304
 305 end:
 306         return ret;
 307 }
 308
 309 /*
 310  *  spawn_sessiond
 311  *
 312  *  Spawn a session daemon by forking and execv.
 313  */
 314 static int spawn_sessiond(char *pathname)
 315 {
 316         int ret = 0;
 317         pid_t pid;
 318
 319         MSG("Spawning a session daemon");
 320         recv_child_signal = 0;
 321         pid = fork();
 322         if (pid == 0) {
 323                 /*
 324                  * Spawn session daemon and tell
 325                  * it to signal us when ready.
 326                  */
 327                 execlp(pathname, "lttng-sessiond", "--sig-parent", "--quiet", NULL);
 328                 /* execlp only returns if error happened */
 329                 if (errno == ENOENT) {
 330                         ERR("No session daemon found. Use --sessiond-path.");
 331                 } else {
 332                         PERROR("execlp");
 333                 }
 334                 kill(getppid(), SIGTERM);       /* wake parent */
 335                 exit(EXIT_FAILURE);
 336         } else if (pid > 0) {
 337                 sessiond_pid = pid;
 338                 /*
 339                  * Wait for lttng-sessiond to start. We need to use a flag to check if
 340                  * the signal has been sent to us, because the child can be scheduled
 341                  * before the parent, and thus send the signal before this check. In
 342                  * the signal handler, we set the recv_child_signal flag, so anytime we
 343                  * check it after the fork is fine. Note that sleep() is interrupted
 344                  * before the 1 second delay as soon as the signal is received, so it
 345                  * will not cause visible delay for the user.
 346                  */
 347                 while (!recv_child_signal) {
 348                         sleep(1);
 349                 }
 350                 /*
 351                  * The signal handler will nullify sessiond_pid on SIGCHLD
 352                  */
 353                 if (!sessiond_pid) {
 354                         exit(EXIT_FAILURE);
 355                 }
 356                 goto end;
 357         } else {
 358                 PERROR("fork");
 359                 ret = -1;
 360                 goto end;
 361         }
 362
 363 end:
 364         return ret;
 365 }
 366
 367 /*
 368  *  check_sessiond
 369  *
 370  *  Check if the session daemon is available using
 371  *  the liblttngctl API for the check. If not, try to
 372  *  spawn a daemon.
 373  */
 374 static int check_sessiond(void)
 375 {
 376         int ret;
 377         char *pathname = NULL;
 378
 379         ret = lttng_session_daemon_alive();
 380         if (ret == 0) { /* not alive */
 381                 /* Try command line option path */
 382                 pathname = opt_sessiond_path;
 383
 384                 /* Try LTTNG_SESSIOND_PATH env variable */
 385                 if (pathname == NULL) {
 386                         pathname = getenv(DEFAULT_SESSIOND_PATH_ENV);
 387                 }
 388
 389                 /* Try with configured path */
 390                 if (pathname == NULL) {
 391                         if (CONFIG_SESSIOND_BIN[0] != '\0') {
 392                                 pathname = CONFIG_SESSIOND_BIN;
 393                         }
 394                 }
 395
 396                 /* Let's rock and roll while trying the default path */
 397                 if (pathname == NULL) {
 398                         pathname = INSTALL_BIN_PATH "/lttng-sessiond";
 399                 }
 400
 401                 DBG("Session daemon at: %s", pathname);
 402
 403                 /* Check existence and permissions */
 404                 ret = access(pathname, F_OK | X_OK);
 405                 if (ret < 0) {
 406                         ERR("No such file or access denied: %s", pathname);
 407                         goto end;
 408                 }
 409
 410                 ret = spawn_sessiond(pathname);
 411                 if (ret < 0) {
 412                         ERR("Problem occurred when starting %s", pathname);
 413                 }
 414         }
 415 end:
 416         return ret;
 417 }
 418
 419 /*
 420  * Check args for specific options that *must* not trigger a session daemon
 421  * execution.
 422  *
 423  * Return 1 if match else 0.
 424  */
 425 static int check_args_no_sessiond(int argc, char **argv)
 426 {
 427         int i;
 428
 429         for (i = 0; i < argc; i++) {
 430                 if ((strncmp(argv[i], "-h", sizeof("-h")) == 0) ||
 431                                 strncmp(argv[i], "--h", sizeof("--h")) == 0 ||
 432                                 strncmp(argv[i], "--list-options", sizeof("--list-options")) == 0 ||
 433                                 strncmp(argv[i], "--list-commands", sizeof("--list-commands")) == 0 ||
 434                                 strncmp(argv[i], "version", sizeof("version")) == 0 ||
 435                                 strncmp(argv[i], "view", sizeof("view")) == 0) {
 436                         return 1;
 437                 }
 438         }
 439
 440         return 0;
 441 }
 442
 443 /*
 444  * Parse command line arguments.
 445  *
 446  * Return 0 if OK, else -1
 447  */
 448 static int parse_args(int argc, char **argv)
 449 {
 450         int opt, ret;
 451         char *user;
 452
 453         if (lttng_is_setuid_setgid()) {
 454                 ERR("'%s' is not allowed to be executed as a setuid/setgid binary for security reasons. Aborting.", argv[0]);
 455                 clean_exit(EXIT_FAILURE);
 456         }
 457
 458         if (argc < 2) {
 459                 usage(stderr);
 460                 clean_exit(EXIT_FAILURE);
 461         }
 462
 463         while ((opt = getopt_long(argc, argv, "+Vhnvqg:m:", long_options, NULL)) != -1) {
 464                 switch (opt) {
 465                 case 'V':
 466                         version(stdout);
 467                         ret = 0;
 468                         goto end;
 469                 case 'h':
 470                         usage(stdout);
 471                         ret = 0;
 472                         goto end;
 473                 case 'v':
 474                         /* There is only 3 possible level of verbosity. (-vvv) */
 475                         if (lttng_opt_verbose < 3) {
 476                                 lttng_opt_verbose += 1;
 477                         }
 478                         break;
 479                 case 'q':
 480                         lttng_opt_quiet = 1;
 481                         break;
 482                 case 'm':
 483                         lttng_opt_mi = mi_output_type(optarg);
 484                         if (lttng_opt_mi < 0) {
 485                                 ret = lttng_opt_mi;
 486                                 goto error;
 487                         }
 488                         break;
 489                 case 'g':
 490                         lttng_set_tracing_group(optarg);
 491                         break;
 492                 case 'n':
 493                         opt_no_sessiond = 1;
 494                         break;
 495                 case OPT_SESSION_PATH:
 496                         opt_sessiond_path = strdup(optarg);
 497                         if (!opt_sessiond_path) {
 498                                 ret = -1;
 499                                 goto error;
 500                         }
 501                         break;
 502                 case OPT_RELAYD_PATH:
 503                         opt_relayd_path = strdup(optarg);
 504                         if (!opt_relayd_path) {
 505                                 ret = -1;
 506                                 goto error;
 507                         }
 508                         break;
 509                 case OPT_DUMP_OPTIONS:
 510                         list_options(stdout);
 511                         ret = 0;
 512                         goto end;
 513                 case OPT_DUMP_COMMANDS:
 514                         list_commands(commands, stdout);
 515                         ret = 0;
 516                         goto end;
 517                 default:
 518                         usage(stderr);
 519                         ret = 1;
 520                         goto error;
 521                 }
 522         }
 523
 524         /* If both options are specified, quiet wins */
 525         if (lttng_opt_verbose && lttng_opt_quiet) {
 526                 lttng_opt_verbose = 0;
 527         }
 528
 529         /* Spawn session daemon if needed */
 530         if (opt_no_sessiond == 0 && check_args_no_sessiond(argc, argv) == 0 &&
 531                         (check_sessiond() < 0)) {
 532                 ret = 1;
 533                 goto error;
 534         }
 535
 536         /* No leftovers, print usage and quit */
 537         if ((argc - optind) == 0) {
 538                 usage(stderr);
 539                 ret = 1;
 540                 goto error;
 541         }
 542
 543         /* For Mathieu Desnoyers a.k.a. Dr. Tracing */
 544         user = getenv("USER");
 545         if (user != NULL && ((strncmp(progname, "drtrace", 7) == 0 ||
 546                                         strncmp("compudj", user, 7) == 0))) {
 547                 MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n", 27,1,33,27,0);
 548         }
 549         /* Thanks Mathieu */
 550
 551         /*
 552          * Handle leftovers which is a first level command with the trailing
 553          * options.
 554          */
 555         ret = handle_command(argc - optind, argv + optind);
 556         switch (ret) {
 557         case CMD_WARNING:
 558                 WARN("Some command(s) went wrong");
 559                 break;
 560         case CMD_ERROR:
 561                 ERR("Command error");
 562                 break;
 563         case CMD_UNDEFINED:
 564                 ERR("Undefined command");
 565                 break;
 566         case CMD_FATAL:
 567                 ERR("Fatal error");
 568                 break;
 569         case CMD_UNSUPPORTED:
 570                 ERR("Unsupported command");
 571                 break;
 572         case -1:
 573                 usage(stderr);
 574                 ret = 1;
 575                 break;
 576         case 0:
 577                 break;
 578         default:
 579                 if (ret < 0) {
 580                         ret = -ret;
 581                 }
 582                 break;
 583         }
 584
 585 end:
 586 error:
 587         return ret;
 588 }
 589
 590
 591 /*
 592  *  main
 593  */
 594 int main(int argc, char *argv[])
 595 {
 596         int ret;
 597
 598         progname = argv[0] ? argv[0] : "lttng";
 599
 600         ret = set_signal_handler();
 601         if (ret < 0) {
 602                 clean_exit(ret);
 603         }
 604
 605         ret = parse_args(argc, argv);
 606         if (ret != 0) {
 607                 clean_exit(ret);
 608         }
 609
 610         return 0;
 611 }