src/bin/lttng/commands/create.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 <assert.h>
  21 #include <ctype.h>
  22 #include <popt.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <sys/stat.h>
  27 #include <sys/types.h>
  28 #include <time.h>
  29 #include <unistd.h>
  30 #include <signal.h>
  31 #include <sys/wait.h>
  32
  33 #include <common/mi-lttng.h>
  34
  35 #include "../command.h"
  36 #include "../utils.h"
  37
  38 #include <common/defaults.h>
  39 #include <common/sessiond-comm/sessiond-comm.h>
  40 #include <common/uri.h>
  41 #include <common/utils.h>
  42 #include <lttng/snapshot.h>
  43
  44 static char *opt_output_path;
  45 static char *opt_session_name;
  46 static char *opt_url;
  47 static char *opt_ctrl_url;
  48 static char *opt_data_url;
  49 static char *opt_shm_path;
  50 static int opt_no_consumer;
  51 static int opt_no_output;
  52 static int opt_snapshot;
  53 static unsigned int opt_live_timer;
  54
  55 enum {
  56         OPT_HELP = 1,
  57         OPT_LIST_OPTIONS,
  58         OPT_LIVE_TIMER,
  59 };
  60
  61 static struct mi_writer *writer;
  62
  63 static struct poptOption long_options[] = {
  64         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  65         {"help", 'h', POPT_ARG_NONE, NULL, OPT_HELP, NULL, NULL},
  66         {"output", 'o', POPT_ARG_STRING, &opt_output_path, 0, NULL, NULL},
  67         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  68         {"set-url",        'U', POPT_ARG_STRING, &opt_url, 0, 0, 0},
  69         {"ctrl-url",       'C', POPT_ARG_STRING, &opt_ctrl_url, 0, 0, 0},
  70         {"data-url",       'D', POPT_ARG_STRING, &opt_data_url, 0, 0, 0},
  71         {"no-output",       0, POPT_ARG_VAL, &opt_no_output, 1, 0, 0},
  72         {"no-consumer",     0, POPT_ARG_VAL, &opt_no_consumer, 1, 0, 0},
  73         {"snapshot",        0, POPT_ARG_VAL, &opt_snapshot, 1, 0, 0},
  74         {"live",            0, POPT_ARG_INT | POPT_ARGFLAG_OPTIONAL, 0, OPT_LIVE_TIMER, 0, 0},
  75         {"shm-path",        0, POPT_ARG_STRING, &opt_shm_path, 0, 0, 0},
  76         {0, 0, 0, 0, 0, 0, 0}
  77 };
  78
  79 /*
  80  * Please have a look at src/lib/lttng-ctl/lttng-ctl.c for more information on
  81  * why this declaration exists and used ONLY in for this command.
  82  */
  83 extern int _lttng_create_session_ext(const char *name, const char *url,
  84                 const char *datetime);
  85
  86 /*
  87  * usage
  88  */
  89 static void usage(FILE *ofp)
  90 {
  91         fprintf(ofp, "usage: lttng create [NAME] [OPTIONS] \n");
  92         fprintf(ofp, "\n");
  93         fprintf(ofp, "Without a given NAME, the default is 'auto-<yyyymmdd>-<hhmmss>'\n");
  94         fprintf(ofp, "\n");
  95         fprintf(ofp, "Options:\n");
  96         fprintf(ofp, "  -h, --help           Show this help\n");
  97         fprintf(ofp, "      --list-options   Simple listing of options\n");
  98         fprintf(ofp, "  -o, --output PATH    Specify output path for traces\n");
  99         fprintf(ofp, "      --no-output      Traces will not be outputted\n");
 100         fprintf(ofp, "      --snapshot       Set the session in snapshot mode.\n");
 101         fprintf(ofp, "                       Created in no-output mode and uses the URL,\n");
 102         fprintf(ofp, "                       if one, as the default snapshot output.\n");
 103         fprintf(ofp, "                       Every channel will be set in overwrite mode\n");
 104         fprintf(ofp, "                       and with mmap output (splice not supported).\n");
 105         fprintf(ofp, "      --live [USEC]    Set the session in live-reading mode.\n");
 106         fprintf(ofp, "                       The delay parameter in micro-seconds is the\n");
 107         fprintf(ofp, "                       maximum time the user can wait for the data\n");
 108         fprintf(ofp, "                       to be flushed. Can be set with a network\n");
 109         fprintf(ofp, "                       URL (-U or -C/-D) and must have a relayd listening.\n");
 110         fprintf(ofp, "                       By default, %u is used for the timer and the\n",
 111                                                                                         DEFAULT_LTTNG_LIVE_TIMER);
 112         fprintf(ofp, "                       network URL is set to net://127.0.0.1.\n");
 113         fprintf(ofp, "      --shm-path PATH  Path where shared memory holding buffers\n");
 114         fprintf(ofp, "                       should be created. Useful when used with pramfs\n");
 115         fprintf(ofp, "                       to extract trace data after crash.\n");
 116         fprintf(ofp, "\n");
 117         fprintf(ofp, "Extended Options:\n");
 118         fprintf(ofp, "\n");
 119         fprintf(ofp, "Using these options, each API call can be controlled individually.\n");
 120         fprintf(ofp, "\n");
 121         fprintf(ofp, "  -U, --set-url=URL    Set URL destination of the trace data.\n");
 122         fprintf(ofp, "                       It is persistent for the session lifetime.\n");
 123         fprintf(ofp, "                       This will set both data and control URL.\n");
 124         fprintf(ofp, "  -C, --ctrl-url=URL   Set control path URL. (Must use -D also)\n");
 125         fprintf(ofp, "  -D, --data-url=URL   Set data path URL. (Must use -C also)\n");
 126         fprintf(ofp, "\n");
 127         fprintf(ofp, "Please refer to the man page (lttng(1)) for more information on network\n");
 128         fprintf(ofp, "streaming mechanisms and explanation of the control and data port\n");
 129         fprintf(ofp, "You must have a running remote lttng-relayd for network streaming\n");
 130         fprintf(ofp, "\n");
 131         fprintf(ofp, "URL format is has followed:\n");
 132         fprintf(ofp, "\n");
 133         fprintf(ofp, "  proto://[HOST|IP][:PORT1[:PORT2]][/TRACE_PATH]\n");
 134         fprintf(ofp, "\n");
 135         fprintf(ofp, "  Supported protocols are (proto):\n");
 136         fprintf(ofp, "  > file://...\n");
 137         fprintf(ofp, "    Local filesystem full path.\n");
 138         fprintf(ofp, "\n");
 139         fprintf(ofp, "  > net[6]://...\n");
 140         fprintf(ofp, "    This will use the default network transport layer which is\n");
 141         fprintf(ofp, "    TCP for both control (PORT1) and data port (PORT2).\n");
 142         fprintf(ofp, "    The default ports are respectively 5342 and 5343.\n");
 143         fprintf(ofp, "\n");
 144         fprintf(ofp, "  > tcp[6]://...\n");
 145         fprintf(ofp, "    Can only be used with -C and -D together\n");
 146         fprintf(ofp, "\n");
 147         fprintf(ofp, "NOTE: IPv6 address MUST be enclosed in brackets '[]' (rfc2732)\n");
 148         fprintf(ofp, "\n");
 149         fprintf(ofp, "Examples:\n");
 150         fprintf(ofp, "    # lttng create -U net://192.168.1.42\n");
 151         fprintf(ofp, "    Uses TCP and default ports for the given destination.\n");
 152         fprintf(ofp, "    # lttng create -U net6://[fe80::f66d:4ff:fe53:d220]\n");
 153         fprintf(ofp, "    Uses TCP, default ports and IPv6.\n");
 154         fprintf(ofp, "    # lttng create s1 -U net://myhost.com:3229\n");
 155         fprintf(ofp, "    Set the consumer to the remote HOST on port 3229 for control.\n");
 156         fprintf(ofp, "\n");
 157 }
 158
 159 /*
 160  * Retrieve the created session and mi output it based on provided argument
 161  * This is currently a summary of what was pretty printed and is subject to
 162  * enhancements.
 163  */
 164 static int mi_created_session(const char *session_name)
 165 {
 166         int ret, i, count, found;
 167         struct lttng_session *sessions;
 168
 169         /* session_name should not be null */
 170         assert(session_name);
 171         assert(writer);
 172
 173         count = lttng_list_sessions(&sessions);
 174         if (count < 0) {
 175                 ret = count;
 176                 ERR("%s", lttng_strerror(ret));
 177                 goto error;
 178         }
 179
 180         if (count == 0) {
 181                 ERR("Error session creation failed: session %s not found", session_name);
 182                 ret = -LTTNG_ERR_SESS_NOT_FOUND;
 183                 goto end;
 184         }
 185
 186         found = 0;
 187         for (i = 0; i < count; i++) {
 188                 if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 189                         found = 1;
 190                         ret = mi_lttng_session(writer, &sessions[i], 0);
 191                         if (ret) {
 192                                 goto error;
 193                         }
 194                         break;
 195                 }
 196         }
 197
 198         if (!found) {
 199                 ret = -LTTNG_ERR_SESS_NOT_FOUND;
 200         } else {
 201                 ret = CMD_SUCCESS;
 202         }
 203
 204 error:
 205         free(sessions);
 206 end:
 207         return ret;
 208 }
 209
 210 /*
 211  * For a session name, set the consumer URLs.
 212  */
 213 static int set_consumer_url(const char *session_name, const char *ctrl_url,
 214                 const char *data_url)
 215 {
 216         int ret;
 217         struct lttng_handle *handle;
 218         struct lttng_domain dom;
 219
 220         assert(session_name);
 221
 222         /*
 223          * Set handle with the session name and the domain set to 0. This means to
 224          * the session daemon that the next action applies on the tracing session
 225          * rather then the domain specific session.
 226          */
 227         memset(&dom, 0, sizeof(dom));
 228
 229         handle = lttng_create_handle(session_name, &dom);
 230         if (handle == NULL) {
 231                 ret = CMD_FATAL;
 232                 goto error;
 233         }
 234
 235         ret = lttng_set_consumer_url(handle, ctrl_url, data_url);
 236         if (ret < 0) {
 237                 goto error;
 238         }
 239
 240         if (ctrl_url) {
 241                 MSG("Control URL %s set for session %s", ctrl_url, session_name);
 242         }
 243
 244         if (data_url) {
 245                 MSG("Data URL %s set for session %s", data_url, session_name);
 246         }
 247
 248 error:
 249         lttng_destroy_handle(handle);
 250         return ret;
 251 }
 252
 253 static int add_snapshot_output(const char *session_name, const char *ctrl_url,
 254                 const char *data_url)
 255 {
 256         int ret;
 257         struct lttng_snapshot_output *output = NULL;
 258
 259         assert(session_name);
 260
 261         output = lttng_snapshot_output_create();
 262         if (!output) {
 263                 ret = CMD_FATAL;
 264                 goto error_create;
 265         }
 266
 267         if (ctrl_url) {
 268                 ret = lttng_snapshot_output_set_ctrl_url(ctrl_url, output);
 269                 if (ret < 0) {
 270                         goto error;
 271                 }
 272         }
 273
 274         if (data_url) {
 275                 ret = lttng_snapshot_output_set_data_url(data_url, output);
 276                 if (ret < 0) {
 277                         goto error;
 278                 }
 279         }
 280
 281         /* This call, if successful, populates the id of the output object. */
 282         ret = lttng_snapshot_add_output(session_name, output);
 283         if (ret < 0) {
 284                 goto error;
 285         }
 286
 287 error:
 288         lttng_snapshot_output_destroy(output);
 289 error_create:
 290         return ret;
 291 }
 292
 293 /*
 294  *  Create a tracing session.
 295  *  If no name is specified, a default name is generated.
 296  *
 297  *  Returns one of the CMD_* result constants.
 298  */
 299 static int create_session(void)
 300 {
 301         int ret;
 302         char *session_name = NULL, *traces_path = NULL, *alloc_path = NULL;
 303         char *alloc_url = NULL, *url = NULL, datetime[16];
 304         char session_name_date[NAME_MAX + 17], *print_str_url = NULL;
 305         time_t rawtime;
 306         struct tm *timeinfo;
 307         char shm_path[PATH_MAX] = "";
 308
 309         /* Get date and time for automatic session name/path */
 310         time(&rawtime);
 311         timeinfo = localtime(&rawtime);
 312         strftime(datetime, sizeof(datetime), "%Y%m%d-%H%M%S", timeinfo);
 313
 314         /* Auto session name creation */
 315         if (opt_session_name == NULL) {
 316                 ret = snprintf(session_name_date, sizeof(session_name_date),
 317                                 DEFAULT_SESSION_NAME "-%s", datetime);
 318                 if (ret < 0) {
 319                         PERROR("snprintf session name");
 320                         goto error;
 321                 }
 322                 session_name = session_name_date;
 323                 DBG("Auto session name set to %s", session_name_date);
 324         } else {
 325                 if (strlen(opt_session_name) > NAME_MAX) {
 326                         ERR("Session name too long. Length must be lower or equal to %d",
 327                                         NAME_MAX);
 328                         ret = LTTNG_ERR_SESSION_FAIL;
 329                         goto error;
 330                 }
 331                 /*
 332                  * Check if the session name begins with "auto-" or is exactly "auto".
 333                  * Both are reserved for the default session name. See bug #449 to
 334                  * understand why we need to check both here.
 335                  */
 336                 if ((strncmp(opt_session_name, DEFAULT_SESSION_NAME "-",
 337                                         strlen(DEFAULT_SESSION_NAME) + 1) == 0) ||
 338                                 (strncmp(opt_session_name, DEFAULT_SESSION_NAME,
 339                                         strlen(DEFAULT_SESSION_NAME)) == 0 &&
 340                                 strlen(opt_session_name) == strlen(DEFAULT_SESSION_NAME))) {
 341                         ERR("%s is a reserved keyword for default session(s)",
 342                                         DEFAULT_SESSION_NAME);
 343                         ret = CMD_ERROR;
 344                         goto error;
 345                 }
 346                 session_name = opt_session_name;
 347                 ret = snprintf(session_name_date, sizeof(session_name_date),
 348                                 "%s-%s", session_name, datetime);
 349                 if (ret < 0) {
 350                         PERROR("snprintf session name");
 351                         goto error;
 352                 }
 353         }
 354
 355         if ((!opt_ctrl_url && opt_data_url) || (opt_ctrl_url && !opt_data_url)) {
 356                 ERR("You need both control and data URL.");
 357                 ret = CMD_ERROR;
 358                 goto error;
 359         }
 360
 361         if (opt_output_path != NULL) {
 362                 traces_path = utils_expand_path(opt_output_path);
 363                 if (traces_path == NULL) {
 364                         ret = CMD_ERROR;
 365                         goto error;
 366                 }
 367
 368                 /* Create URL string from the local file system path */
 369                 ret = asprintf(&alloc_url, "file://%s", traces_path);
 370                 if (ret < 0) {
 371                         PERROR("asprintf url path");
 372                         ret = CMD_FATAL;
 373                         goto error;
 374                 }
 375                 /* URL to use in the lttng_create_session() call */
 376                 url = alloc_url;
 377                 print_str_url = traces_path;
 378         } else if (opt_url) { /* Handling URL (-U opt) */
 379                 url = opt_url;
 380                 print_str_url = url;
 381         } else if (opt_data_url && opt_ctrl_url) {
 382                 /*
 383                  * With both control and data, we'll be setting the consumer URL after
 384                  * session creation thus use no URL.
 385                  */
 386                 url = NULL;
 387         } else if (!opt_no_output) {
 388                 char *tmp_path;
 389
 390                 /* Auto output path */
 391                 tmp_path = utils_get_home_dir();
 392                 if (tmp_path == NULL) {
 393                         ERR("HOME path not found.\n \
 394                                         Please specify an output path using -o, --output PATH");
 395                         ret = CMD_FATAL;
 396                         goto error;
 397                 }
 398                 alloc_path = strdup(tmp_path);
 399                 if (!alloc_path) {
 400                         PERROR("allocating alloc_path");
 401                         ret = CMD_FATAL;
 402                         goto error;
 403                 }
 404                 ret = asprintf(&alloc_url,
 405                                 "file://%s/" DEFAULT_TRACE_DIR_NAME "/%s",
 406                                 alloc_path, session_name_date);
 407                 if (ret < 0) {
 408                         PERROR("asprintf trace dir name");
 409                         ret = CMD_FATAL;
 410                         goto error;
 411                 }
 412
 413                 url = alloc_url;
 414                 print_str_url = alloc_url + strlen("file://");
 415         } else {
 416                 /* No output means --no-output or --snapshot mode. */
 417                 url = NULL;
 418         }
 419
 420         /* Use default live URL if NO url is/are found. */
 421         if ((opt_live_timer && !opt_url) && (opt_live_timer && !opt_data_url)) {
 422                 ret = asprintf(&alloc_url, "net://127.0.0.1");
 423                 if (ret < 0) {
 424                         PERROR("asprintf default live URL");
 425                         ret = CMD_FATAL;
 426                         goto error;
 427                 }
 428                 url = alloc_url;
 429                 print_str_url = url;
 430         }
 431
 432         if (opt_snapshot && opt_live_timer) {
 433                 ERR("Snapshot and live modes are mutually exclusive.");
 434                 ret = CMD_ERROR;
 435                 goto error;
 436         }
 437
 438         if (opt_snapshot) {
 439                 /* No output by default. */
 440                 const char *snapshot_url = NULL;
 441
 442                 if (opt_url) {
 443                         snapshot_url = url;
 444                 } else if (!opt_data_url && !opt_ctrl_url) {
 445                         /* This is the session path that we need to use as output. */
 446                         snapshot_url = url;
 447                 }
 448                 ret = lttng_create_session_snapshot(session_name, snapshot_url);
 449         } else if (opt_live_timer) {
 450                 const char *pathname;
 451
 452                 if (opt_relayd_path) {
 453                         pathname = opt_relayd_path;
 454                 } else {
 455                         pathname = INSTALL_BIN_PATH "/lttng-relayd";
 456                 }
 457                 if (!opt_url && !opt_data_url && !check_relayd() &&
 458                                 spawn_relayd(pathname, 0) < 0) {
 459                         goto error;
 460                 }
 461                 ret = lttng_create_session_live(session_name, url, opt_live_timer);
 462         } else {
 463                 ret = _lttng_create_session_ext(session_name, url, datetime);
 464         }
 465         if (ret < 0) {
 466                 /* Don't set ret so lttng can interpret the sessiond error. */
 467                 switch (-ret) {
 468                 case LTTNG_ERR_EXIST_SESS:
 469                         WARN("Session %s already exists", session_name);
 470                         break;
 471                 default:
 472                         break;
 473                 }
 474                 goto error;
 475         }
 476
 477         if (opt_ctrl_url && opt_data_url) {
 478                 if (opt_snapshot) {
 479                         ret = add_snapshot_output(session_name, opt_ctrl_url,
 480                                         opt_data_url);
 481                 } else {
 482                         /* Setting up control URI (-C or/and -D opt) */
 483                         ret = set_consumer_url(session_name, opt_ctrl_url, opt_data_url);
 484                 }
 485                 if (ret < 0) {
 486                         /* Destroy created session because the URL are not valid. */
 487                         lttng_destroy_session(session_name);
 488                         goto error;
 489                 }
 490         }
 491
 492         if (opt_shm_path) {
 493                 ret = snprintf(shm_path, sizeof(shm_path),
 494                                 "%s/%s", opt_shm_path, session_name_date);
 495                 if (ret < 0) {
 496                         PERROR("snprintf shm_path");
 497                         goto error;
 498                 }
 499
 500                 ret = lttng_set_session_shm_path(session_name, shm_path);
 501                 if (ret < 0) {
 502                         lttng_destroy_session(session_name);
 503                         goto error;
 504                 }
 505         }
 506
 507         MSG("Session %s created.", session_name);
 508         if (print_str_url && !opt_snapshot) {
 509                 MSG("Traces will be written in %s", print_str_url);
 510
 511                 if (opt_live_timer) {
 512                         MSG("Live timer set to %u usec", opt_live_timer);
 513                 }
 514         } else if (opt_snapshot) {
 515                 if (print_str_url) {
 516                         MSG("Default snapshot output set to: %s", print_str_url);
 517                 }
 518                 MSG("Snapshot mode set. Every channel enabled for that session will "
 519                                 "be set in overwrite mode and mmap output.");
 520         }
 521         if (opt_shm_path) {
 522                 MSG("Session %s set to shm_path: %s.", session_name,
 523                         shm_path);
 524         }
 525
 526         /* Mi output */
 527         if (lttng_opt_mi) {
 528                 ret = mi_created_session(session_name);
 529                 if (ret) {
 530                         ret = CMD_ERROR;
 531                         goto error;
 532                 }
 533         }
 534
 535         /* Init lttng session config */
 536         ret = config_init(session_name);
 537         if (ret < 0) {
 538                 ret = CMD_ERROR;
 539                 goto error;
 540         }
 541
 542         ret = CMD_SUCCESS;
 543
 544 error:
 545         free(alloc_url);
 546         free(traces_path);
 547         free(alloc_path);
 548
 549         if (ret < 0) {
 550                 ERR("%s", lttng_strerror(ret));
 551         }
 552         return ret;
 553 }
 554
 555 /*
 556  *  spawn_sessiond
 557  *
 558  *  Spawn a session daemon by forking and execv.
 559  */
 560 static int spawn_sessiond(char *pathname)
 561 {
 562         int ret = 0;
 563         pid_t pid;
 564
 565         MSG("Spawning a session daemon");
 566         pid = fork();
 567         if (pid == 0) {
 568                 /*
 569                  * Spawn session daemon in daemon mode.
 570                  */
 571                 execlp(pathname, "lttng-sessiond",
 572                                 "--daemonize", NULL);
 573                 /* execlp only returns if error happened */
 574                 if (errno == ENOENT) {
 575                         ERR("No session daemon found. Use --sessiond-path.");
 576                 } else {
 577                         PERROR("execlp");
 578                 }
 579                 kill(getppid(), SIGTERM);       /* wake parent */
 580                 exit(EXIT_FAILURE);
 581         } else if (pid > 0) {
 582                 /*
 583                  * In daemon mode (--daemonize), sessiond only exits when
 584                  * it's ready to accept commands.
 585                  */
 586                 for (;;) {
 587                         int status;
 588                         pid_t wait_pid_ret = waitpid(pid, &status, 0);
 589
 590                         if (wait_pid_ret < 0) {
 591                                 if (errno == EINTR) {
 592                                         continue;
 593                                 }
 594                                 PERROR("waitpid");
 595                                 ret = -errno;
 596                                 goto end;
 597                         }
 598
 599                         if (WIFSIGNALED(status)) {
 600                                 ERR("Session daemon was killed by signal %d",
 601                                                 WTERMSIG(status));
 602                                 ret = -1;
 603                                 goto end;
 604                         } else if (WIFEXITED(status)) {
 605                                 DBG("Session daemon terminated normally (exit status: %d)",
 606                                                 WEXITSTATUS(status));
 607
 608                                 if (WEXITSTATUS(status) != 0) {
 609                                         ERR("Session daemon terminated with an error (exit status: %d)",
 610                                                         WEXITSTATUS(status));
 611                                         ret = -1;
 612                                         goto end;
 613                                 }
 614                                 break;
 615                         }
 616                 }
 617
 618                 goto end;
 619         } else {
 620                 PERROR("fork");
 621                 ret = -1;
 622                 goto end;
 623         }
 624
 625 end:
 626         return ret;
 627 }
 628
 629 /*
 630  *  launch_sessiond
 631  *
 632  *  Check if the session daemon is available using
 633  *  the liblttngctl API for the check. If not, try to
 634  *  spawn a daemon.
 635  */
 636 static int launch_sessiond(void)
 637 {
 638         int ret;
 639         char *pathname = NULL;
 640
 641         ret = lttng_session_daemon_alive();
 642         if (ret) {
 643                 /* Sessiond is alive, not an error */
 644                 ret = 0;
 645                 goto end;
 646         }
 647
 648         /* Try command line option path */
 649         pathname = opt_sessiond_path;
 650
 651         /* Try LTTNG_SESSIOND_PATH env variable */
 652         if (pathname == NULL) {
 653                 pathname = getenv(DEFAULT_SESSIOND_PATH_ENV);
 654         }
 655
 656         /* Try with configured path */
 657         if (pathname == NULL) {
 658                 if (CONFIG_SESSIOND_BIN[0] != '\0') {
 659                         pathname = CONFIG_SESSIOND_BIN;
 660                 }
 661         }
 662
 663         /* Try the default path */
 664         if (pathname == NULL) {
 665                 pathname = INSTALL_BIN_PATH "/lttng-sessiond";
 666         }
 667
 668         DBG("Session daemon binary path: %s", pathname);
 669
 670         /* Check existence and permissions */
 671         ret = access(pathname, F_OK | X_OK);
 672         if (ret < 0) {
 673                 ERR("No such file or access denied: %s", pathname);
 674                 goto end;
 675         }
 676
 677         ret = spawn_sessiond(pathname);
 678 end:
 679         if (ret) {
 680                 ERR("Problem occurred while launching session daemon (%s)",
 681                                 pathname);
 682         }
 683         return ret;
 684 }
 685
 686 /*
 687  *  The 'create <options>' first level command
 688  *
 689  *  Returns one of the CMD_* result constants.
 690  */
 691 int cmd_create(int argc, const char **argv)
 692 {
 693         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 694         char *opt_arg = NULL;
 695         static poptContext pc;
 696
 697         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 698         poptReadDefaultConfig(pc, 0);
 699
 700         while ((opt = poptGetNextOpt(pc)) != -1) {
 701                 switch (opt) {
 702                 case OPT_HELP:
 703                         usage(stdout);
 704                         goto end;
 705                 case OPT_LIST_OPTIONS:
 706                         list_cmd_options(stdout, long_options);
 707                         goto end;
 708                 case OPT_LIVE_TIMER:
 709                 {
 710                         unsigned long v;
 711
 712                         errno = 0;
 713                         opt_arg = poptGetOptArg(pc);
 714                         if (!opt_arg) {
 715                                 /* Set up default values. */
 716                                 opt_live_timer = (uint32_t) DEFAULT_LTTNG_LIVE_TIMER;
 717                                 DBG("Session live timer interval set to default value %d",
 718                                                 opt_live_timer);
 719                                 break;
 720                         }
 721
 722                         v = strtoul(opt_arg, NULL, 0);
 723                         if (errno != 0 || !isdigit(opt_arg[0])) {
 724                                 ERR("Wrong value in --live parameter: %s", opt_arg);
 725                                 ret = CMD_ERROR;
 726                                 goto end;
 727                         }
 728                         if (v != (uint32_t) v) {
 729                                 ERR("32-bit overflow in --live parameter: %s", opt_arg);
 730                                 ret = CMD_ERROR;
 731                                 goto end;
 732                         }
 733                         if (v == 0) {
 734                                 ERR("Live timer interval must be greater than zero");
 735                                 ret = CMD_ERROR;
 736                                 goto end;
 737                         }
 738                         opt_live_timer = (uint32_t) v;
 739                         DBG("Session live timer interval set to %d", opt_live_timer);
 740                         break;
 741                 }
 742                 default:
 743                         usage(stderr);
 744                         ret = CMD_UNDEFINED;
 745                         goto end;
 746                 }
 747         }
 748
 749         if (opt_no_consumer) {
 750                 MSG("The option --no-consumer is obsolete. Use --no-output now.");
 751                 ret = CMD_WARNING;
 752                 goto end;
 753         }
 754
 755         /* Spawn a session daemon if needed */
 756         if (!opt_no_sessiond) {
 757                 ret = launch_sessiond();
 758                 if (ret) {
 759                         ret = CMD_ERROR;
 760                         goto end;
 761                 }
 762         }
 763
 764         /* MI initialization */
 765         if (lttng_opt_mi) {
 766                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 767                 if (!writer) {
 768                         ret = -LTTNG_ERR_NOMEM;
 769                         goto end;
 770                 }
 771
 772                 /* Open command element */
 773                 ret = mi_lttng_writer_command_open(writer,
 774                                 mi_lttng_element_command_create);
 775                 if (ret) {
 776                         ret = CMD_ERROR;
 777                         goto end;
 778                 }
 779
 780                 /* Open output element */
 781                 ret = mi_lttng_writer_open_element(writer,
 782                                 mi_lttng_element_command_output);
 783                 if (ret) {
 784                         ret = CMD_ERROR;
 785                         goto end;
 786                 }
 787         }
 788         opt_session_name = (char*) poptGetArg(pc);
 789
 790         command_ret = create_session();
 791         if (command_ret) {
 792                 success = 0;
 793         }
 794
 795         if (lttng_opt_mi) {
 796                 /* Close  output element */
 797                 ret = mi_lttng_writer_close_element(writer);
 798                 if (ret) {
 799                         ret = CMD_ERROR;
 800                         goto end;
 801                 }
 802
 803                 /* Success ? */
 804                 ret = mi_lttng_writer_write_element_bool(writer,
 805                                 mi_lttng_element_command_success, success);
 806                 if (ret) {
 807                         ret = CMD_ERROR;
 808                         goto end;
 809                 }
 810
 811                 /* Command element close */
 812                 ret = mi_lttng_writer_command_close(writer);
 813                 if (ret) {
 814                         ret = CMD_ERROR;
 815                         goto end;
 816                 }
 817         }
 818
 819 end:
 820         /* Mi clean-up */
 821         if (writer && mi_lttng_writer_destroy(writer)) {
 822                 /* Preserve original error code */
 823                 ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
 824         }
 825
 826         /* Overwrite ret if an error occurred in create_session() */
 827         ret = command_ret ? command_ret : ret;
 828
 829         poptFreeContext(pc);
 830         return ret;
 831 }