src/bin/lttng/commands/create.cpp

   1 /*
   2  * Copyright (C) 2011 EfficiOS Inc.
   3  * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * SPDX-License-Identifier: GPL-2.0-only
   6  *
   7  */
   8
   9 #define _LGPL_SOURCE
  10 #include <ctype.h>
  11 #include <popt.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/stat.h>
  16 #include <sys/types.h>
  17 #include <common/compat/time.h>
  18 #include <unistd.h>
  19 #include <signal.h>
  20 #include <sys/wait.h>
  21
  22 #include <common/mi-lttng.h>
  23
  24 #include "../command.h"
  25 #include "../utils.h"
  26
  27 #include <common/defaults.h>
  28 #include <common/sessiond-comm/sessiond-comm.h>
  29 #include <common/uri.h>
  30 #include <common/utils.h>
  31 #include <common/path.h>
  32 #include <lttng/lttng.h>
  33
  34 static char *opt_output_path;
  35 static char *opt_session_name;
  36 static char *opt_url;
  37 static char *opt_ctrl_url;
  38 static char *opt_data_url;
  39 static char *opt_shm_path;
  40 static int opt_no_consumer;
  41 static int opt_no_output;
  42 static int opt_snapshot;
  43 static uint32_t opt_live_timer;
  44
  45 #ifdef LTTNG_EMBED_HELP
  46 static const char help_msg[] =
  47 #include <lttng-create.1.h>
  48 ;
  49 #endif
  50
  51 enum {
  52         OPT_HELP = 1,
  53         OPT_LIST_OPTIONS,
  54         OPT_LIVE_TIMER,
  55 };
  56
  57 enum output_type {
  58         OUTPUT_NONE,
  59         OUTPUT_LOCAL,
  60         OUTPUT_NETWORK,
  61         OUTPUT_UNSPECIFIED,
  62 };
  63
  64 static struct mi_writer *writer;
  65 static struct poptOption long_options[] = {
  66         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  67         {"help", 'h', POPT_ARG_NONE, NULL, OPT_HELP, NULL, NULL},
  68         {"output", 'o', POPT_ARG_STRING, &opt_output_path, 0, NULL, NULL},
  69         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  70         {"set-url",        'U', POPT_ARG_STRING, &opt_url, 0, 0, 0},
  71         {"ctrl-url",       'C', POPT_ARG_STRING, &opt_ctrl_url, 0, 0, 0},
  72         {"data-url",       'D', POPT_ARG_STRING, &opt_data_url, 0, 0, 0},
  73         {"no-output",       0, POPT_ARG_VAL, &opt_no_output, 1, 0, 0},
  74         {"no-consumer",     0, POPT_ARG_VAL, &opt_no_consumer, 1, 0, 0},
  75         {"snapshot",        0, POPT_ARG_VAL, &opt_snapshot, 1, 0, 0},
  76         {"live",            0, POPT_ARG_INT | POPT_ARGFLAG_OPTIONAL, 0, OPT_LIVE_TIMER, 0, 0},
  77         {"shm-path",        0, POPT_ARG_STRING, &opt_shm_path, 0, 0, 0},
  78         {0, 0, 0, 0, 0, 0, 0}
  79 };
  80
  81 /*
  82  * Retrieve the created session and mi output it based on provided argument
  83  * This is currently a summary of what was pretty printed and is subject to
  84  * enhancements.
  85  */
  86 static int mi_created_session(const char *session_name)
  87 {
  88         int ret, i, count, found;
  89         struct lttng_session *sessions;
  90
  91         /* session_name should not be null */
  92         LTTNG_ASSERT(session_name);
  93         LTTNG_ASSERT(writer);
  94
  95         count = lttng_list_sessions(&sessions);
  96         if (count < 0) {
  97                 ret = count;
  98                 ERR("%s", lttng_strerror(ret));
  99                 goto error;
 100         }
 101
 102         if (count == 0) {
 103                 ERR("Error session creation failed: session %s not found", session_name);
 104                 ret = -LTTNG_ERR_SESS_NOT_FOUND;
 105                 goto end;
 106         }
 107
 108         found = 0;
 109         for (i = 0; i < count; i++) {
 110                 if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 111                         found = 1;
 112                         ret = mi_lttng_session(writer, &sessions[i], 0);
 113                         if (ret) {
 114                                 goto error;
 115                         }
 116                         break;
 117                 }
 118         }
 119
 120         if (!found) {
 121                 ret = -LTTNG_ERR_SESS_NOT_FOUND;
 122         } else {
 123                 ret = CMD_SUCCESS;
 124         }
 125
 126 error:
 127         free(sessions);
 128 end:
 129         return ret;
 130 }
 131
 132 static
 133 struct lttng_session_descriptor *create_session_descriptor(void)
 134 {
 135         ssize_t uri_count;
 136         enum output_type output_type;
 137         struct lttng_uri *uris = NULL;
 138         struct lttng_session_descriptor *descriptor = NULL;
 139         const char *uri_str1 = NULL, *uri_str2 = NULL;
 140         char local_output_path[LTTNG_PATH_MAX] = {};
 141
 142         if (opt_no_output) {
 143                 output_type = OUTPUT_NONE;
 144         } else if (opt_output_path) {
 145                 char *expanded_output_path;
 146                 int ret;
 147
 148                 output_type = OUTPUT_LOCAL;
 149                 expanded_output_path = utils_expand_path(opt_output_path);
 150                 if (!expanded_output_path) {
 151                         ERR("Failed to expand output path.");
 152                         goto end;
 153                 }
 154                 ret = lttng_strncpy(local_output_path, expanded_output_path,
 155                                 sizeof(local_output_path));
 156                 free(expanded_output_path);
 157                 if (ret) {
 158                         ERR("Output path exceeds the maximal supported length (%zu bytes)",
 159                                         sizeof(local_output_path));
 160                         goto end;
 161                 }
 162         } else if (opt_url || opt_ctrl_url) {
 163                 int ret;
 164
 165                 uri_str1 = opt_ctrl_url ? opt_ctrl_url : opt_url;
 166                 uri_str2 = opt_data_url;
 167
 168                 uri_count = uri_parse_str_urls(uri_str1, uri_str2, &uris);
 169                 if (uri_count != 1 && uri_count != 2) {
 170                         ERR("Unrecognized URL format.");
 171                         goto end;
 172                 }
 173
 174                 switch (uri_count) {
 175                 case 1:
 176                         output_type = OUTPUT_LOCAL;
 177                         if (uris[0].dtype != LTTNG_DST_PATH) {
 178                                 ERR("Unrecognized URL format.");
 179                                 goto end;
 180                         }
 181                         ret = lttng_strncpy(local_output_path, uris[0].dst.path,
 182                                         sizeof(local_output_path));
 183                         if (ret) {
 184                                 ERR("Output path exceeds the maximal supported length (%zu bytes)",
 185                                                 sizeof(local_output_path));
 186                         }
 187                         break;
 188                 case 2:
 189                         output_type = OUTPUT_NETWORK;
 190                         break;
 191                 default:
 192                         /* Already checked. */
 193                         abort();
 194                 }
 195         } else {
 196                 output_type = OUTPUT_UNSPECIFIED;
 197         }
 198
 199         if (opt_snapshot) {
 200                 /* Snapshot session. */
 201                 switch (output_type) {
 202                 case OUTPUT_UNSPECIFIED:
 203                 case OUTPUT_LOCAL:
 204                         descriptor = lttng_session_descriptor_snapshot_local_create(
 205                                         opt_session_name,
 206                                         output_type == OUTPUT_LOCAL ?
 207                                                 local_output_path : NULL);
 208                         break;
 209                 case OUTPUT_NONE:
 210                         descriptor = lttng_session_descriptor_snapshot_create(
 211                                         opt_session_name);
 212                         break;
 213                 case OUTPUT_NETWORK:
 214                         descriptor = lttng_session_descriptor_snapshot_network_create(
 215                                         opt_session_name, uri_str1, uri_str2);
 216                         break;
 217                 default:
 218                         abort();
 219                 }
 220         } else if (opt_live_timer) {
 221                 /* Live session. */
 222                 if (output_type != OUTPUT_UNSPECIFIED &&
 223                                 output_type != OUTPUT_NETWORK) {
 224                         ERR("Unsupported output type specified for live session.");
 225                         goto end;
 226                 }
 227                 descriptor = lttng_session_descriptor_live_network_create(
 228                                 opt_session_name, uri_str1, uri_str2,
 229                                 opt_live_timer);
 230         } else {
 231                 /* Regular session. */
 232                 switch (output_type) {
 233                 case OUTPUT_UNSPECIFIED:
 234                 case OUTPUT_LOCAL:
 235                         descriptor = lttng_session_descriptor_local_create(
 236                                         opt_session_name,
 237                                         output_type == OUTPUT_LOCAL ?
 238                                                 local_output_path : NULL);
 239                         break;
 240                 case OUTPUT_NONE:
 241                         descriptor = lttng_session_descriptor_create(
 242                                         opt_session_name);
 243                         break;
 244                 case OUTPUT_NETWORK:
 245                         descriptor = lttng_session_descriptor_network_create(
 246                                         opt_session_name, uri_str1, uri_str2);
 247                         break;
 248                 default:
 249                         abort();
 250                 }
 251         }
 252         if (!descriptor) {
 253                 ERR("Failed to initialize session creation command.");
 254         } else {
 255                 /*
 256                  * Auto-launch the relay daemon when a live session
 257                  * is created using default URLs.
 258                  */
 259                 if (!opt_url && !opt_ctrl_url && !opt_data_url &&
 260                                 opt_live_timer && !check_relayd()) {
 261                         int ret;
 262                         const char *pathname = opt_relayd_path ? :
 263                                         INSTALL_BIN_PATH "/lttng-relayd";
 264
 265                         ret = spawn_relayd(pathname, 0);
 266                         if (ret < 0) {
 267                                 lttng_session_descriptor_destroy(descriptor);
 268                                 descriptor = NULL;
 269                         }
 270                 }
 271         }
 272 end:
 273         free(uris);
 274         return descriptor;
 275 }
 276
 277 /*
 278  *  Create a tracing session.
 279  *  If no name is specified, a default name is generated.
 280  *
 281  *  Returns one of the CMD_* result constants.
 282  */
 283 static int create_session(void)
 284 {
 285         int ret, i;
 286         char shm_path[LTTNG_PATH_MAX] = {};
 287         struct lttng_session_descriptor *session_descriptor = NULL;
 288         enum lttng_session_descriptor_status descriptor_status;
 289         enum lttng_error_code ret_code;
 290         struct lttng_session *sessions = NULL;
 291         const struct lttng_session *created_session = NULL;
 292         const char *created_session_name;
 293
 294         /* Validate options. */
 295         if (opt_session_name) {
 296                 if (strlen(opt_session_name) > NAME_MAX) {
 297                         ERR("Session name too long. Length must be lower or equal to %d",
 298                                         NAME_MAX);
 299                         ret = CMD_ERROR;
 300                         goto error;
 301                 }
 302                 /*
 303                  * Check if the session name begins with "auto-" or is exactly "auto".
 304                  * Both are reserved for the default session name. See bug #449 to
 305                  * understand why we need to check both here.
 306                  */
 307                 if ((strncmp(opt_session_name, DEFAULT_SESSION_NAME "-",
 308                                         strlen(DEFAULT_SESSION_NAME) + 1) == 0) ||
 309                                 (strncmp(opt_session_name, DEFAULT_SESSION_NAME,
 310                                         strlen(DEFAULT_SESSION_NAME)) == 0 &&
 311                                 strlen(opt_session_name) == strlen(DEFAULT_SESSION_NAME))) {
 312                         ERR("%s is a reserved keyword for default session(s)",
 313                                         DEFAULT_SESSION_NAME);
 314                         ret = CMD_ERROR;
 315                         goto error;
 316                 }
 317         }
 318
 319         if (opt_snapshot && opt_live_timer) {
 320                 ERR("Snapshot and live modes are mutually exclusive.");
 321                 ret = CMD_ERROR;
 322                 goto error;
 323         }
 324
 325         if ((!opt_ctrl_url && opt_data_url) || (opt_ctrl_url && !opt_data_url)) {
 326                 ERR("Both control and data URLs must be specified.");
 327                 ret = CMD_ERROR;
 328                 goto error;
 329         }
 330
 331         session_descriptor = create_session_descriptor();
 332         if (!session_descriptor) {
 333                 ret = CMD_ERROR;
 334                 goto error;
 335         }
 336         ret_code = lttng_create_session_ext(session_descriptor);
 337         if (ret_code != LTTNG_OK) {
 338                 ERR("%s", lttng_strerror(-ret_code));
 339                 ret = CMD_ERROR;
 340                 goto error;
 341         }
 342
 343         descriptor_status = lttng_session_descriptor_get_session_name(
 344                 session_descriptor, &created_session_name);
 345         if (descriptor_status != LTTNG_SESSION_DESCRIPTOR_STATUS_OK) {
 346                 ERR("Failed to obtain created session name");
 347                 ret = CMD_ERROR;
 348                 goto error;
 349         }
 350
 351         ret = lttng_list_sessions(&sessions);
 352         if (ret < 0) {
 353                 ERR("Failed to fetch properties of created session: %s",
 354                                 lttng_strerror(ret));
 355                 ret = CMD_ERROR;
 356                 goto error;
 357         }
 358         for (i = 0; i < ret; i++) {
 359                 if (!strcmp(created_session_name, sessions[i].name)) {
 360                         created_session = &sessions[i];
 361                         break;
 362                 }
 363         }
 364         if (!created_session) {
 365                 ERR("Failed to fetch properties of created session");
 366                 ret = CMD_ERROR;
 367                 goto error;
 368         }
 369
 370         if (opt_shm_path) {
 371                 char datetime_suffix[17] = {};
 372
 373                 /*
 374                  * An auto-generated session name already includes the creation
 375                  * timestamp.
 376                  */
 377                 if (opt_session_name) {
 378                         uint64_t creation_time;
 379                         struct tm *timeinfo;
 380                         time_t creation_time_t;
 381                         size_t strftime_ret;
 382
 383                         ret_code = lttng_session_get_creation_time(
 384                                         created_session,
 385                                         &creation_time);
 386                         if (ret_code != LTTNG_OK) {
 387                                 ERR("%s", lttng_strerror(-ret_code));
 388                                 ret = CMD_ERROR;
 389                                 goto error;
 390                         }
 391                         creation_time_t = (time_t) creation_time;
 392                         timeinfo = localtime(&creation_time_t);
 393                         if (!timeinfo) {
 394                                 PERROR("Failed to interpret session creation time");
 395                                 ret = CMD_ERROR;
 396                                 goto error;
 397                         }
 398                         strftime_ret = strftime(datetime_suffix,
 399                                         sizeof(datetime_suffix),
 400                                         "-%Y%m%d-%H%M%S", timeinfo);
 401                         if (strftime_ret == 0) {
 402                                 ERR("Failed to format session creation time.");
 403                                 ret = CMD_ERROR;
 404                                 goto error;
 405                         }
 406                 }
 407
 408                 ret = snprintf(shm_path, sizeof(shm_path),
 409                                 "%s/%s%s", opt_shm_path, created_session_name,
 410                                 datetime_suffix);
 411                 if (ret < 0 || ret >= sizeof(shm_path)) {
 412                         ERR("Failed to format the shared memory path.");
 413                         ret = CMD_ERROR;
 414                         goto error;
 415                 }
 416                 ret = lttng_set_session_shm_path(created_session_name,
 417                                 shm_path);
 418                 if (ret < 0) {
 419                         lttng_destroy_session(created_session_name);
 420                         ret = CMD_ERROR;
 421                         goto error;
 422                 }
 423         }
 424
 425         if (opt_snapshot) {
 426                 MSG("Snapshot session %s created.", created_session_name);
 427         } else if (opt_live_timer) {
 428                 MSG("Live session %s created.", created_session_name);
 429         } else {
 430                 MSG("Session %s created.", created_session_name);
 431         }
 432
 433         if (*created_session->path && !opt_snapshot) {
 434                 MSG("Traces will be output to %s", created_session->path);
 435
 436                 if (opt_live_timer) {
 437                         MSG("Live timer interval set to %u %s", opt_live_timer,
 438                                         USEC_UNIT);
 439                 }
 440         } else if (opt_snapshot) {
 441                 struct lttng_snapshot_output_list *list;
 442                 struct lttng_snapshot_output *iter;
 443                 char snapshot_url[LTTNG_PATH_MAX] = {};
 444
 445                 ret = lttng_snapshot_list_output(created_session_name, &list);
 446                 if (ret < 0) {
 447                         ERR("Failed to list snapshot outputs.");
 448                         ret = CMD_ERROR;
 449                         goto error;
 450                 }
 451
 452                 while ((iter = lttng_snapshot_output_list_get_next(list))) {
 453                         const char *url = NULL;
 454
 455                         url = lttng_snapshot_output_get_ctrl_url(
 456                                         iter);
 457                         ret = lttng_strncpy(snapshot_url, url,
 458                                         sizeof(snapshot_url));
 459                         if (ret) {
 460                                 snapshot_url[0] = '\0';
 461                                 ERR("Failed to retrieve snapshot output destination");
 462                         }
 463                         break;
 464                 }
 465                 lttng_snapshot_output_list_destroy(list);
 466
 467                 if (*snapshot_url) {
 468                         MSG("Default snapshot output set to %s",
 469                                         snapshot_url);
 470                 }
 471                 MSG("Every channel enabled for this session will be set to mmap output and default to overwrite mode.");
 472         }
 473         if (opt_shm_path) {
 474                 MSG("Shared memory path set to %s", shm_path);
 475         }
 476
 477         /* Mi output */
 478         if (lttng_opt_mi) {
 479                 ret = mi_created_session(created_session_name);
 480                 if (ret) {
 481                         ret = CMD_ERROR;
 482                         goto error;
 483                 }
 484         }
 485
 486         /* Init lttng session config */
 487         ret = config_init(created_session_name);
 488         if (ret < 0) {
 489                 ret = CMD_ERROR;
 490                 goto error;
 491         }
 492
 493         ret = CMD_SUCCESS;
 494 error:
 495         lttng_session_descriptor_destroy(session_descriptor);
 496         free(sessions);
 497         return ret;
 498 }
 499
 500 /*
 501  *  spawn_sessiond
 502  *
 503  *  Spawn a session daemon by forking and execv.
 504  */
 505 static int spawn_sessiond(const char *pathname)
 506 {
 507         int ret = 0;
 508         pid_t pid;
 509
 510         MSG("Spawning a session daemon");
 511         pid = fork();
 512         if (pid == 0) {
 513                 /*
 514                  * Spawn session daemon in daemon mode.
 515                  */
 516                 execlp(pathname, "lttng-sessiond",
 517                                 "--daemonize", NULL);
 518                 /* execlp only returns if error happened */
 519                 if (errno == ENOENT) {
 520                         ERR("No session daemon found. Use --sessiond-path.");
 521                 } else {
 522                         PERROR("execlp");
 523                 }
 524                 kill(getppid(), SIGTERM);       /* wake parent */
 525                 exit(EXIT_FAILURE);
 526         } else if (pid > 0) {
 527                 /*
 528                  * In daemon mode (--daemonize), sessiond only exits when
 529                  * it's ready to accept commands.
 530                  */
 531                 for (;;) {
 532                         int status;
 533                         pid_t wait_pid_ret = waitpid(pid, &status, 0);
 534
 535                         if (wait_pid_ret < 0) {
 536                                 if (errno == EINTR) {
 537                                         continue;
 538                                 }
 539                                 PERROR("waitpid");
 540                                 ret = -errno;
 541                                 goto end;
 542                         }
 543
 544                         if (WIFSIGNALED(status)) {
 545                                 ERR("Session daemon was killed by signal %d",
 546                                                 WTERMSIG(status));
 547                                 ret = -1;
 548                                 goto end;
 549                         } else if (WIFEXITED(status)) {
 550                                 DBG("Session daemon terminated normally (exit status: %d)",
 551                                                 WEXITSTATUS(status));
 552
 553                                 if (WEXITSTATUS(status) != 0) {
 554                                         ERR("Session daemon terminated with an error (exit status: %d)",
 555                                                         WEXITSTATUS(status));
 556                                         ret = -1;
 557                                         goto end;
 558                                 }
 559                                 break;
 560                         }
 561                 }
 562
 563                 goto end;
 564         } else {
 565                 PERROR("fork");
 566                 ret = -1;
 567                 goto end;
 568         }
 569
 570 end:
 571         return ret;
 572 }
 573
 574 /*
 575  *  launch_sessiond
 576  *
 577  *  Check if the session daemon is available using
 578  *  the liblttngctl API for the check. If not, try to
 579  *  spawn a daemon.
 580  */
 581 static int launch_sessiond(void)
 582 {
 583         int ret;
 584         const char *pathname = NULL;
 585
 586         ret = lttng_session_daemon_alive();
 587         if (ret) {
 588                 /* Sessiond is alive, not an error */
 589                 ret = 0;
 590                 goto end;
 591         }
 592
 593         /* Try command line option path */
 594         pathname = opt_sessiond_path;
 595
 596         /* Try LTTNG_SESSIOND_PATH env variable */
 597         if (pathname == NULL) {
 598                 pathname = getenv(DEFAULT_SESSIOND_PATH_ENV);
 599         }
 600
 601         /* Try with configured path */
 602         if (pathname == NULL) {
 603                 if (CONFIG_SESSIOND_BIN[0] != '\0') {
 604                         pathname = CONFIG_SESSIOND_BIN;
 605                 }
 606         }
 607
 608         /* Try the default path */
 609         if (pathname == NULL) {
 610                 pathname = INSTALL_BIN_PATH "/lttng-sessiond";
 611         }
 612
 613         DBG("Session daemon binary path: %s", pathname);
 614
 615         /* Check existence and permissions */
 616         ret = access(pathname, F_OK | X_OK);
 617         if (ret < 0) {
 618                 ERR("No such file or access denied: %s", pathname);
 619                 goto end;
 620         }
 621
 622         ret = spawn_sessiond(pathname);
 623 end:
 624         if (ret) {
 625                 ERR("Problem occurred while launching session daemon (%s)",
 626                                 pathname);
 627         }
 628         return ret;
 629 }
 630
 631 static
 632 int validate_url_option_combination(void)
 633 {
 634         int ret = 0;
 635         int used_count = 0;
 636
 637         used_count += !!opt_url;
 638         used_count += !!opt_output_path;
 639         used_count += (opt_data_url || opt_ctrl_url);
 640         if (used_count > 1) {
 641                 ERR("Only one of the --set-url, --ctrl-url/data-url, or --output options may be used at once.");
 642                 ret = -1;
 643         }
 644
 645         return ret;
 646 }
 647
 648 /*
 649  *  The 'create <options>' first level command
 650  *
 651  *  Returns one of the CMD_* result constants.
 652  */
 653 int cmd_create(int argc, const char **argv)
 654 {
 655         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 656         char *opt_arg = NULL;
 657         const char *leftover = NULL;
 658         static poptContext pc;
 659
 660         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 661         poptReadDefaultConfig(pc, 0);
 662
 663         while ((opt = poptGetNextOpt(pc)) != -1) {
 664                 switch (opt) {
 665                 case OPT_HELP:
 666                         SHOW_HELP();
 667                         goto end;
 668                 case OPT_LIST_OPTIONS:
 669                         list_cmd_options(stdout, long_options);
 670                         goto end;
 671                 case OPT_LIVE_TIMER:
 672                 {
 673                         uint64_t v;
 674
 675                         errno = 0;
 676                         opt_arg = poptGetOptArg(pc);
 677                         if (!opt_arg) {
 678                                 /* Set up default values. */
 679                                 opt_live_timer = (uint32_t) DEFAULT_LTTNG_LIVE_TIMER;
 680                                 DBG("Session live timer interval set to default value %d",
 681                                                 opt_live_timer);
 682                                 break;
 683                         }
 684
 685                         if (utils_parse_time_suffix(opt_arg, &v) < 0) {
 686                                 ERR("Wrong value for --live parameter: %s", opt_arg);
 687                                 ret = CMD_ERROR;
 688                                 goto end;
 689                         }
 690
 691                         if (v != (uint32_t) v) {
 692                                 ERR("32-bit overflow in --live parameter: %s", opt_arg);
 693                                 ret = CMD_ERROR;
 694                                 goto end;
 695                         }
 696
 697                         if (v == 0) {
 698                                 ERR("Live timer interval must be greater than zero");
 699                                 ret = CMD_ERROR;
 700                                 goto end;
 701                         }
 702
 703                         opt_live_timer = (uint32_t) v;
 704                         DBG("Session live timer interval set to %d", opt_live_timer);
 705                         break;
 706                 }
 707                 default:
 708                         ret = CMD_UNDEFINED;
 709                         goto end;
 710                 }
 711         }
 712
 713         if (opt_no_consumer) {
 714                 MSG("The option --no-consumer is obsolete. Use --no-output now.");
 715                 ret = CMD_WARNING;
 716                 goto end;
 717         }
 718
 719         ret = validate_url_option_combination();
 720         if (ret) {
 721                 ret = CMD_ERROR;
 722                 goto end;
 723         }
 724
 725         /* Spawn a session daemon if needed */
 726         if (!opt_no_sessiond) {
 727                 ret = launch_sessiond();
 728                 if (ret) {
 729                         ret = CMD_ERROR;
 730                         goto end;
 731                 }
 732         }
 733
 734         /* MI initialization */
 735         if (lttng_opt_mi) {
 736                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 737                 if (!writer) {
 738                         ret = -LTTNG_ERR_NOMEM;
 739                         goto end;
 740                 }
 741
 742                 /* Open command element */
 743                 ret = mi_lttng_writer_command_open(writer,
 744                                 mi_lttng_element_command_create);
 745                 if (ret) {
 746                         ret = CMD_ERROR;
 747                         goto end;
 748                 }
 749
 750                 /* Open output element */
 751                 ret = mi_lttng_writer_open_element(writer,
 752                                 mi_lttng_element_command_output);
 753                 if (ret) {
 754                         ret = CMD_ERROR;
 755                         goto end;
 756                 }
 757         }
 758         opt_session_name = (char*) poptGetArg(pc);
 759
 760         leftover = poptGetArg(pc);
 761         if (leftover) {
 762                 ERR("Unknown argument: %s", leftover);
 763                 ret = CMD_ERROR;
 764                 goto end;
 765         }
 766
 767         command_ret = create_session();
 768         if (command_ret) {
 769                 success = 0;
 770         }
 771
 772         if (lttng_opt_mi) {
 773                 /* Close  output element */
 774                 ret = mi_lttng_writer_close_element(writer);
 775                 if (ret) {
 776                         ret = CMD_ERROR;
 777                         goto end;
 778                 }
 779
 780                 /* Success ? */
 781                 ret = mi_lttng_writer_write_element_bool(writer,
 782                                 mi_lttng_element_command_success, success);
 783                 if (ret) {
 784                         ret = CMD_ERROR;
 785                         goto end;
 786                 }
 787
 788                 /* Command element close */
 789                 ret = mi_lttng_writer_command_close(writer);
 790                 if (ret) {
 791                         ret = CMD_ERROR;
 792                         goto end;
 793                 }
 794         }
 795
 796 end:
 797         /* Mi clean-up */
 798         if (writer && mi_lttng_writer_destroy(writer)) {
 799                 /* Preserve original error code */
 800                 ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
 801         }
 802
 803         /* Overwrite ret if an error occurred in create_session() */
 804         ret = command_ret ? command_ret : ret;
 805
 806         poptFreeContext(pc);
 807         return ret;
 808 }