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