src/bin/lttng/commands/track-untrack.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C) 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _LGPL_SOURCE
  20 #include <ctype.h>
  21 #include <popt.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/stat.h>
  26 #include <sys/types.h>
  27 #include <unistd.h>
  28 #include <assert.h>
  29
  30 #include <urcu/list.h>
  31
  32 #include <common/mi-lttng.h>
  33
  34 #include "../command.h"
  35
  36 enum cmd_type {
  37         CMD_TRACK,
  38         CMD_UNTRACK,
  39 };
  40
  41 enum tracker_type_state {
  42         STATE_NONE = 0,
  43         STATE_PID,
  44         STATE_VPID,
  45         STATE_UID,
  46         STATE_VUID,
  47         STATE_GID,
  48         STATE_VGID,
  49 };
  50
  51 struct opt_type {
  52         int used;
  53         int all;
  54         char *string;
  55 };
  56
  57 struct id_list {
  58         size_t nr;
  59         struct lttng_tracker_id **array;
  60 };
  61
  62 static char *opt_session_name;
  63 static int opt_kernel;
  64 static int opt_userspace;
  65
  66 static struct opt_type opt_pid, opt_vpid, opt_uid, opt_vuid, opt_gid, opt_vgid;
  67
  68 static enum tracker_type_state type_state;
  69
  70 enum {
  71         OPT_HELP = 1,
  72         OPT_LIST_OPTIONS,
  73         OPT_SESSION,
  74         OPT_PID,
  75         OPT_VPID,
  76         OPT_UID,
  77         OPT_VUID,
  78         OPT_GID,
  79         OPT_VGID,
  80         OPT_ALL,
  81 };
  82
  83 static struct poptOption long_options[] = {
  84         /* { longName, shortName, argInfo, argPtr, value, descrip, argDesc, } */
  85         { "help",               'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0, },
  86         { "session",            's', POPT_ARG_STRING, &opt_session_name, OPT_SESSION, 0, 0, },
  87         { "kernel",             'k', POPT_ARG_VAL, &opt_kernel, 1, 0, 0, },
  88         { "userspace",          'u', POPT_ARG_VAL, &opt_userspace, 1, 0, 0, },
  89         { "pid",                'p', POPT_ARG_STRING | POPT_ARGFLAG_OPTIONAL, &opt_pid.string, OPT_PID, 0, 0, },
  90         { "vpid",               0, POPT_ARG_STRING | POPT_ARGFLAG_OPTIONAL, &opt_vpid.string, OPT_VPID, 0, 0, },
  91         { "uid",                0, POPT_ARG_STRING | POPT_ARGFLAG_OPTIONAL, &opt_uid.string, OPT_UID, 0, 0, },
  92         { "vuid",               0, POPT_ARG_STRING | POPT_ARGFLAG_OPTIONAL, &opt_vuid.string, OPT_VUID, 0, 0, },
  93         { "gid",                0, POPT_ARG_STRING | POPT_ARGFLAG_OPTIONAL, &opt_gid.string, OPT_GID, 0, 0, },
  94         { "vgid",               0, POPT_ARG_STRING | POPT_ARGFLAG_OPTIONAL, &opt_vgid.string, OPT_VGID, 0, 0, },
  95         { "all",                'a', POPT_ARG_NONE, 0, OPT_ALL, 0, 0, },
  96         { "list-options",       0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, 0, 0, },
  97         { 0, 0, 0, 0, 0, 0, 0, },
  98 };
  99
 100 static struct id_list *alloc_id_list(size_t nr_items)
 101 {
 102         struct id_list *id_list;
 103         struct lttng_tracker_id **items;
 104
 105         id_list = zmalloc(sizeof(*id_list));
 106         if (!id_list) {
 107                 goto error;
 108         }
 109         items = zmalloc(nr_items * sizeof(*items));
 110         if (!items) {
 111                 goto error;
 112         }
 113         id_list->nr = nr_items;
 114         id_list->array = items;
 115         return id_list;
 116 error:
 117         free(id_list);
 118         return NULL;
 119 }
 120
 121 static void free_id_list(struct id_list *list)
 122 {
 123         size_t nr_items;
 124         int i;
 125
 126         if (!list) {
 127                 return;
 128         }
 129         nr_items = list->nr;
 130         for (i = 0; i < nr_items; i++) {
 131                 struct lttng_tracker_id *item = list->array[i];
 132                 lttng_tracker_id_destroy(item);
 133         }
 134         free(list);
 135 }
 136
 137 static int parse_id_string(const char *_id_string,
 138                 int all,
 139                 struct id_list **_id_list,
 140                 enum lttng_tracker_type tracker_type)
 141 {
 142         const char *one_id_str;
 143         char *iter;
 144         int retval = CMD_SUCCESS;
 145         int count = 0;
 146         struct id_list *id_list = NULL;
 147         char *id_string = NULL;
 148         char *endptr;
 149
 150         if (all && _id_string) {
 151                 ERR("An empty ID string is expected with --all");
 152                 retval = CMD_ERROR;
 153                 goto error;
 154         }
 155         if (!all && !_id_string) {
 156                 ERR("An ID string is expected");
 157                 retval = CMD_ERROR;
 158                 goto error;
 159         }
 160         if (all) {
 161                 enum lttng_tracker_id_status status;
 162                 /* Empty `ID string means all IDs */
 163                 id_list = alloc_id_list(1);
 164                 if (!id_list) {
 165                         ERR("Out of memory");
 166                         retval = CMD_ERROR;
 167                         goto error;
 168                 }
 169
 170                 id_list->array[0] = lttng_tracker_id_create();
 171                 if (id_list->array[0] == NULL) {
 172                         ERR("Out of memory");
 173                         retval = CMD_ERROR;
 174                         goto error;
 175                 }
 176
 177                 status = lttng_tracker_id_set_all(id_list->array[0]);
 178                 if (status != LTTNG_TRACKER_ID_STATUS_OK) {
 179                         ERR("Invalid value for tracker id");
 180                         retval = CMD_ERROR;
 181                         goto error;
 182                 }
 183                 goto assign;
 184         }
 185
 186         id_string = strdup(_id_string);
 187         if (!id_string) {
 188                 ERR("Out of memory");
 189                 retval = CMD_ERROR;
 190                 goto error;
 191         }
 192
 193         /* Count */
 194         one_id_str = strtok_r(id_string, ",", &iter);
 195         while (one_id_str != NULL) {
 196                 unsigned long v;
 197
 198                 if (isdigit(one_id_str[0])) {
 199                         errno = 0;
 200                         v = strtoul(one_id_str, &endptr, 10);
 201                         if ((v == 0 && errno == EINVAL) ||
 202                                         (v == ULONG_MAX && errno == ERANGE) ||
 203                                         (*one_id_str != '\0' &&
 204                                                         *endptr != '\0')) {
 205                                 ERR("Error parsing ID %s", one_id_str);
 206                                 retval = CMD_ERROR;
 207                                 goto error;
 208                         }
 209
 210                         if ((long) v > INT_MAX || (int) v < 0) {
 211                                 ERR("Invalid ID value %ld", (long) v);
 212                                 retval = CMD_ERROR;
 213                                 goto error;
 214                         }
 215                 }
 216                 count++;
 217
 218                 /* For next loop */
 219                 one_id_str = strtok_r(NULL, ",", &iter);
 220         }
 221         if (count == 0) {
 222                 ERR("Fatal error occurred when parsing pid string");
 223                 retval = CMD_ERROR;
 224                 goto error;
 225         }
 226
 227         free(id_string);
 228         /* Identity of delimiter has been lost in first pass. */
 229         id_string = strdup(_id_string);
 230         if (!id_string) {
 231                 ERR("Out of memory");
 232                 retval = CMD_ERROR;
 233                 goto error;
 234         }
 235
 236         /* Allocate */
 237         id_list = alloc_id_list(count);
 238         if (!id_list) {
 239                 ERR("Out of memory");
 240                 retval = CMD_ERROR;
 241                 goto error;
 242         }
 243
 244         /* Reparse string and populate the id list. */
 245         count = 0;
 246         one_id_str = strtok_r(id_string, ",", &iter);
 247         while (one_id_str != NULL) {
 248                 enum lttng_tracker_id_status status;
 249                 struct lttng_tracker_id *item;
 250                 item = lttng_tracker_id_create();
 251                 if (item == NULL) {
 252                         ERR("Out of memory");
 253                         retval = CMD_ERROR;
 254                         goto error;
 255                 }
 256
 257                 id_list->array[count++] = item;
 258                 if (isdigit(one_id_str[0])) {
 259                         unsigned long v;
 260
 261                         v = strtoul(one_id_str, NULL, 10);
 262                         status = lttng_tracker_id_set_value(item, (int) v);
 263                         if (status == LTTNG_TRACKER_ID_STATUS_INVALID) {
 264                                 ERR("Invalid value");
 265                                 retval = CMD_ERROR;
 266                                 goto error;
 267                         }
 268                 } else {
 269                         status = lttng_tracker_id_set_string(item, one_id_str);
 270                         if (status == LTTNG_TRACKER_ID_STATUS_INVALID) {
 271                                 ERR("Failed to set ID string");
 272                                 retval = CMD_ERROR;
 273                                 goto error;
 274                         }
 275                 }
 276
 277                 /* For next loop */
 278                 one_id_str = strtok_r(NULL, ",", &iter);
 279         }
 280
 281 assign:
 282         /* SUCCESS */
 283         *_id_list = id_list;
 284         goto end;
 285
 286 error:
 287         /* ERROR */
 288         free_id_list(id_list);
 289 end:
 290         free(id_string);
 291         return retval;
 292 }
 293
 294 static const char *get_tracker_str(enum lttng_tracker_type tracker_type)
 295 {
 296         switch (tracker_type) {
 297         case LTTNG_TRACKER_PID:
 298                 return "PID";
 299         case LTTNG_TRACKER_VPID:
 300                 return "VPID";
 301         case LTTNG_TRACKER_UID:
 302                 return "UID";
 303         case LTTNG_TRACKER_VUID:
 304                 return "VUID";
 305         case LTTNG_TRACKER_GID:
 306                 return "GID";
 307         case LTTNG_TRACKER_VGID:
 308                 return "VGID";
 309         default:
 310                 return NULL;
 311         }
 312         return NULL;
 313 }
 314
 315 static int ust_tracker_type_support(enum lttng_tracker_type *tracker_type)
 316 {
 317         int ret;
 318
 319         switch (*tracker_type) {
 320         case LTTNG_TRACKER_PID:
 321                 *tracker_type = LTTNG_TRACKER_VPID;
 322                 ret = 0;
 323                 break;
 324         case LTTNG_TRACKER_VPID:
 325         case LTTNG_TRACKER_VUID:
 326         case LTTNG_TRACKER_VGID:
 327                 ret = 0;
 328                 break;
 329         case LTTNG_TRACKER_UID:
 330         case LTTNG_TRACKER_GID:
 331                 ERR("The %s tracker is invalid for UST domain.",
 332                                 get_tracker_str(*tracker_type));
 333                 ret = -1;
 334                 break;
 335         default:
 336                 ret = -1;
 337                 break;
 338         }
 339
 340         return ret;
 341 }
 342
 343 static enum cmd_error_code track_untrack_id(enum cmd_type cmd_type,
 344                 const char *cmd_str,
 345                 const char *session_name,
 346                 const char *id_string,
 347                 int all,
 348                 struct mi_writer *writer,
 349                 enum lttng_tracker_type tracker_type)
 350 {
 351         int ret, success = 1 , i;
 352         enum cmd_error_code retval = CMD_SUCCESS;
 353         struct id_list *id_list = NULL;
 354         struct lttng_domain dom;
 355         struct lttng_handle *handle = NULL;
 356         int (*cmd_func)(struct lttng_handle *handle,
 357                         enum lttng_tracker_type tracker_type,
 358                         const struct lttng_tracker_id *id);
 359         const char *tracker_str;
 360
 361         switch (cmd_type) {
 362         case CMD_TRACK:
 363                 cmd_func = lttng_track_id;
 364                 break;
 365         case CMD_UNTRACK:
 366                 cmd_func = lttng_untrack_id;
 367                 break;
 368         default:
 369                 ERR("Unknown command");
 370                 retval = CMD_ERROR;
 371                 goto end;
 372         }
 373         memset(&dom, 0, sizeof(dom));
 374         if (opt_kernel) {
 375                 dom.type = LTTNG_DOMAIN_KERNEL;
 376         } else if (opt_userspace) {
 377                 dom.type = LTTNG_DOMAIN_UST;
 378                 ret = ust_tracker_type_support(&tracker_type);
 379                 if (ret) {
 380                         ERR("Invalid parameter");
 381                         retval = CMD_ERROR;
 382                         goto end;
 383                 }
 384         } else {
 385                 /* Checked by the caller. */
 386                 assert(0);
 387         }
 388         tracker_str = get_tracker_str(tracker_type);
 389         if (!tracker_str) {
 390                 ERR("Unknown tracker type");
 391                 retval = CMD_ERROR;
 392                 goto end;
 393         }
 394         ret = parse_id_string(id_string, all, &id_list, tracker_type);
 395         if (ret != CMD_SUCCESS) {
 396                 ERR("Error parsing %s string", tracker_str);
 397                 retval = CMD_ERROR;
 398                 goto end;
 399         }
 400
 401         handle = lttng_create_handle(session_name, &dom);
 402         if (handle == NULL) {
 403                 retval = CMD_ERROR;
 404                 goto end;
 405         }
 406
 407         if (writer) {
 408                 /* Open tracker_id and targets elements */
 409                 ret = mi_lttng_id_tracker_open(writer, tracker_type);
 410                 if (ret) {
 411                         goto end;
 412                 }
 413         }
 414
 415         for (i = 0; i < id_list->nr; i++) {
 416                 struct lttng_tracker_id *item = id_list->array[i];
 417                 enum lttng_tracker_id_type type =
 418                                 lttng_tracker_id_get_type(item);
 419                 enum lttng_tracker_id_status status =
 420                                 LTTNG_TRACKER_ID_STATUS_OK;
 421                 int value;
 422                 const char *value_string;
 423
 424                 switch (type) {
 425                 case LTTNG_ID_ALL:
 426                         /* Nothing to check */
 427                         break;
 428                 case LTTNG_ID_VALUE:
 429                         status = lttng_tracker_id_get_value(item, &value);
 430                         break;
 431                 case LTTNG_ID_STRING:
 432                         status = lttng_tracker_id_get_string(
 433                                         item, &value_string);
 434                         break;
 435                 default:
 436                         retval = CMD_ERROR;
 437                         goto end;
 438                 }
 439
 440                 if (status != LTTNG_TRACKER_ID_STATUS_OK) {
 441                         ERR("Tracker id object is in an invalid state");
 442                         retval = CMD_ERROR;
 443                         goto end;
 444                 }
 445
 446                 switch (type) {
 447                 case LTTNG_ID_ALL:
 448                         DBG("%s all IDs", cmd_str);
 449                         break;
 450                 case LTTNG_ID_VALUE:
 451                         DBG("%s ID %d", cmd_str, value);
 452                         break;
 453                 case LTTNG_ID_STRING:
 454                         DBG("%s ID '%s'", cmd_str, value_string);
 455                         break;
 456                 default:
 457                         retval = CMD_ERROR;
 458                         goto end;
 459                 }
 460
 461                 ret = cmd_func(handle, tracker_type, item);
 462                 if (ret) {
 463                         char *msg = NULL;
 464
 465                         switch (-ret) {
 466                         case LTTNG_ERR_ID_TRACKED:
 467                                 msg = "already tracked";
 468                                 success = 1;
 469                                 retval = CMD_SUCCESS;
 470                                 break;
 471                         case LTTNG_ERR_ID_NOT_TRACKED:
 472                                 msg = "already not tracked";
 473                                 success = 1;
 474                                 retval = CMD_SUCCESS;
 475                                 break;
 476                         default:
 477                                 ERR("%s", lttng_strerror(ret));
 478                                 success = 0;
 479                                 retval = CMD_ERROR;
 480                                 break;
 481                         }
 482                         if (msg) {
 483                                 switch (type) {
 484                                 case LTTNG_ID_ALL:
 485                                         WARN("All %ss %s in session %s",
 486                                                         tracker_str, msg,
 487                                                         session_name);
 488                                         break;
 489                                 case LTTNG_ID_VALUE:
 490                                         WARN("%s %i %s in session %s",
 491                                                         tracker_str, value, msg,
 492                                                         session_name);
 493                                         break;
 494                                 case LTTNG_ID_STRING:
 495                                         WARN("%s '%s' %s in session %s",
 496                                                         tracker_str,
 497                                                         value_string, msg,
 498                                                         session_name);
 499                                         break;
 500                                 default:
 501                                         retval = CMD_ERROR;
 502                                         goto end;
 503                                 }
 504                         }
 505                 } else {
 506                         switch (type) {
 507                         case LTTNG_ID_ALL:
 508                                 MSG("All %ss %sed in session %s", tracker_str,
 509                                                 cmd_str, session_name);
 510                                 break;
 511                         case LTTNG_ID_VALUE:
 512                                 MSG("%s %i %sed in session %s", tracker_str,
 513                                                 value, cmd_str, session_name);
 514                                 break;
 515                         case LTTNG_ID_STRING:
 516                                 MSG("%s '%s' %sed in session %s", tracker_str,
 517                                                 value_string, cmd_str,
 518                                                 session_name);
 519                                 break;
 520                         default:
 521                                 retval = CMD_ERROR;
 522                                 goto end;
 523                         }
 524                         success = 1;
 525                 }
 526
 527                 /* Mi */
 528                 if (writer) {
 529                         ret = mi_lttng_id_target(writer, tracker_type, item, 1);
 530                         if (ret) {
 531                                 retval = CMD_ERROR;
 532                                 goto end;
 533                         }
 534
 535                         ret = mi_lttng_writer_write_element_bool(writer,
 536                                         mi_lttng_element_success, success);
 537                         if (ret) {
 538                                 retval = CMD_ERROR;
 539                                 goto end;
 540                         }
 541
 542                         ret = mi_lttng_writer_close_element(writer);
 543                         if (ret) {
 544                                 retval = CMD_ERROR;
 545                                 goto end;
 546                         }
 547                 }
 548         }
 549
 550         if (writer) {
 551                 /* Close targets and tracker_id elements */
 552                 ret = mi_lttng_close_multi_element(writer, 2);
 553                 if (ret) {
 554                         retval = CMD_ERROR;
 555                         goto end;
 556                 }
 557         }
 558
 559 end:
 560         if (handle) {
 561                 lttng_destroy_handle(handle);
 562         }
 563         free_id_list(id_list);
 564         return retval;
 565 }
 566
 567 static
 568 const char *get_mi_element_command(enum cmd_type cmd_type)
 569 {
 570         switch (cmd_type) {
 571         case CMD_TRACK:
 572                 return mi_lttng_element_command_track;
 573         case CMD_UNTRACK:
 574                 return mi_lttng_element_command_untrack;
 575         default:
 576                 return NULL;
 577         }
 578 }
 579
 580 static void print_err_duplicate(const char *type)
 581 {
 582         ERR("The --%s option can only be used once. A list of comma-separated values can be specified.",
 583                         type);
 584 }
 585
 586 /*
 587  * Add/remove tracker to/from session.
 588  */
 589 static
 590 int cmd_track_untrack(enum cmd_type cmd_type, const char *cmd_str,
 591                 int argc, const char **argv, const char *help_msg)
 592 {
 593         int opt, ret = 0, success = 1;
 594         enum cmd_error_code command_ret = CMD_SUCCESS;
 595         static poptContext pc;
 596         char *session_name = NULL;
 597         const char *leftover = NULL;
 598         struct mi_writer *writer = NULL;
 599
 600         if (argc < 1) {
 601                 command_ret = CMD_ERROR;
 602                 goto end;
 603         }
 604
 605         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 606         poptReadDefaultConfig(pc, 0);
 607
 608         while ((opt = poptGetNextOpt(pc)) != -1) {
 609                 switch (opt) {
 610                 case OPT_HELP:
 611                         SHOW_HELP();
 612                         goto end;
 613                 case OPT_LIST_OPTIONS:
 614                         list_cmd_options(stdout, long_options);
 615                         goto end;
 616                 case OPT_SESSION:
 617                         break;
 618                 case OPT_PID:
 619                         if (opt_pid.used) {
 620                                 print_err_duplicate("pid");
 621                                 command_ret = CMD_ERROR;
 622                                 goto end;
 623                         }
 624                         opt_pid.used = 1;
 625                         type_state = STATE_PID;
 626                         break;
 627                 case OPT_VPID:
 628                         if (opt_vpid.used) {
 629                                 print_err_duplicate("vpid");
 630                                 command_ret = CMD_ERROR;
 631                                 goto end;
 632                         }
 633                         opt_vpid.used = 1;
 634                         type_state = STATE_VPID;
 635                         break;
 636                 case OPT_UID:
 637                         if (opt_uid.used) {
 638                                 print_err_duplicate("uid");
 639                                 command_ret = CMD_ERROR;
 640                                 goto end;
 641                         }
 642                         opt_uid.used = 1;
 643                         type_state = STATE_UID;
 644                         break;
 645                 case OPT_VUID:
 646                         if (opt_vuid.used) {
 647                                 print_err_duplicate("vuid");
 648                                 command_ret = CMD_ERROR;
 649                                 goto end;
 650                         }
 651                         opt_vuid.used = 1;
 652                         type_state = STATE_VUID;
 653                         break;
 654                 case OPT_GID:
 655                         if (opt_gid.used) {
 656                                 print_err_duplicate("gid");
 657                                 command_ret = CMD_ERROR;
 658                                 goto end;
 659                         }
 660                         opt_gid.used = 1;
 661                         type_state = STATE_GID;
 662                         break;
 663                 case OPT_VGID:
 664                         if (opt_vgid.used) {
 665                                 print_err_duplicate("vgid");
 666                                 command_ret = CMD_ERROR;
 667                                 goto end;
 668                         }
 669                         opt_vgid.used = 1;
 670                         type_state = STATE_VGID;
 671                         break;
 672                 case OPT_ALL:
 673                         switch (type_state) {
 674                         case STATE_PID:
 675                                 opt_pid.all = 1;
 676                                 break;
 677                         case STATE_VPID:
 678                                 opt_vpid.all = 1;
 679                                 break;
 680                         case STATE_UID:
 681                                 opt_uid.all = 1;
 682                                 break;
 683                         case STATE_VUID:
 684                                 opt_vuid.all = 1;
 685                                 break;
 686                         case STATE_GID:
 687                                 opt_gid.all = 1;
 688                                 break;
 689                         case STATE_VGID:
 690                                 opt_vgid.all = 1;
 691                                 break;
 692                         default:
 693                                 command_ret = CMD_ERROR;
 694                                 goto end;
 695                         }
 696                         break;
 697                 default:
 698                         command_ret = CMD_UNDEFINED;
 699                         goto end;
 700                 }
 701         }
 702
 703         ret = print_missing_or_multiple_domains(opt_kernel + opt_userspace);
 704         if (ret) {
 705                 command_ret = CMD_ERROR;
 706                 goto end;
 707         }
 708
 709         if (!opt_session_name) {
 710                 session_name = get_session_name();
 711                 if (session_name == NULL) {
 712                         command_ret = CMD_ERROR;
 713                         goto end;
 714                 }
 715         } else {
 716                 session_name = opt_session_name;
 717         }
 718
 719         leftover = poptGetArg(pc);
 720         if (leftover) {
 721                 ERR("Unknown argument: %s", leftover);
 722                 ret = CMD_ERROR;
 723                 goto end;
 724         }
 725
 726         /* Mi check */
 727         if (lttng_opt_mi) {
 728                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 729                 if (!writer) {
 730                         command_ret = CMD_ERROR;
 731                         goto end;
 732                 }
 733         }
 734
 735         if (writer) {
 736                 /* Open command element */
 737                 ret = mi_lttng_writer_command_open(writer,
 738                                 get_mi_element_command(cmd_type));
 739                 if (ret) {
 740                         command_ret = CMD_ERROR;
 741                         goto end;
 742                 }
 743
 744                 /* Open output element */
 745                 ret = mi_lttng_writer_open_element(writer,
 746                                 mi_lttng_element_command_output);
 747                 if (ret) {
 748                         command_ret = CMD_ERROR;
 749                         goto end;
 750                 }
 751
 752                 ret = mi_lttng_trackers_open(writer);
 753                 if (ret) {
 754                         goto end;
 755                 }
 756         }
 757
 758         if (opt_pid.used) {
 759                 command_ret = track_untrack_id(cmd_type, cmd_str, session_name,
 760                                 opt_pid.string, opt_pid.all, writer,
 761                                 LTTNG_TRACKER_PID);
 762                 if (command_ret != CMD_SUCCESS) {
 763                         success = 0;
 764                 }
 765         }
 766         if (opt_vpid.used) {
 767                 command_ret = track_untrack_id(cmd_type, cmd_str, session_name,
 768                                 opt_vpid.string, opt_vpid.all, writer,
 769                                 LTTNG_TRACKER_VPID);
 770                 if (command_ret != CMD_SUCCESS) {
 771                         success = 0;
 772                 }
 773         }
 774         if (opt_uid.used) {
 775                 command_ret = track_untrack_id(cmd_type, cmd_str, session_name,
 776                                 opt_uid.string, opt_uid.all, writer,
 777                                 LTTNG_TRACKER_UID);
 778                 if (command_ret != CMD_SUCCESS) {
 779                         success = 0;
 780                 }
 781         }
 782         if (opt_vuid.used) {
 783                 command_ret = track_untrack_id(cmd_type, cmd_str, session_name,
 784                                 opt_vuid.string, opt_vuid.all, writer,
 785                                 LTTNG_TRACKER_VUID);
 786                 if (command_ret != CMD_SUCCESS) {
 787                         success = 0;
 788                 }
 789         }
 790         if (opt_gid.used) {
 791                 command_ret = track_untrack_id(cmd_type, cmd_str, session_name,
 792                                 opt_gid.string, opt_gid.all, writer,
 793                                 LTTNG_TRACKER_GID);
 794                 if (command_ret != CMD_SUCCESS) {
 795                         success = 0;
 796                 }
 797         }
 798         if (opt_vgid.used) {
 799                 command_ret = track_untrack_id(cmd_type, cmd_str, session_name,
 800                                 opt_vgid.string, opt_vgid.all, writer,
 801                                 LTTNG_TRACKER_VGID);
 802                 if (command_ret != CMD_SUCCESS) {
 803                         success = 0;
 804                 }
 805         }
 806
 807         /* Mi closing */
 808         if (writer) {
 809                 /* Close trackers and output elements */
 810                 ret = mi_lttng_close_multi_element(writer, 2);
 811                 if (ret) {
 812                         command_ret = CMD_ERROR;
 813                         goto end;
 814                 }
 815
 816                 /* Success ? */
 817                 ret = mi_lttng_writer_write_element_bool(writer,
 818                                 mi_lttng_element_command_success, success);
 819                 if (ret) {
 820                         command_ret = CMD_ERROR;
 821                         goto end;
 822                 }
 823
 824                 /* Command element close */
 825                 ret = mi_lttng_writer_command_close(writer);
 826                 if (ret) {
 827                         command_ret = CMD_ERROR;
 828                         goto end;
 829                 }
 830         }
 831
 832 end:
 833         if (!opt_session_name) {
 834                 free(session_name);
 835         }
 836
 837         /* Mi clean-up */
 838         if (writer && mi_lttng_writer_destroy(writer)) {
 839                 /* Preserve original error code */
 840                 command_ret = CMD_ERROR;
 841         }
 842
 843         poptFreeContext(pc);
 844         return (int) command_ret;
 845 }
 846
 847 int cmd_track(int argc, const char **argv)
 848 {
 849         static const char *help_msg =
 850 #ifdef LTTNG_EMBED_HELP
 851 #include <lttng-track.1.h>
 852 #else
 853         NULL
 854 #endif
 855         ;
 856
 857         return cmd_track_untrack(CMD_TRACK, "track", argc, argv, help_msg);
 858 }
 859
 860 int cmd_untrack(int argc, const char **argv)
 861 {
 862         static const char *help_msg =
 863 #ifdef LTTNG_EMBED_HELP
 864 #include <lttng-untrack.1.h>
 865 #else
 866         NULL
 867 #endif
 868         ;
 869
 870         return cmd_track_untrack(CMD_UNTRACK, "untrack", argc, argv, help_msg);
 871 }