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