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