src/bin/lttng/commands/create.c

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