liblttngctl/lttngctl.c

   1 /*
   2  * liblttngctl.c
   3  *
   4  * Linux Trace Toolkit Control Library
   5  *
   6  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #define _GNU_SOURCE
  24 #include <grp.h>
  25 #include <errno.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30
  31 #include <lttng-sessiond-comm.h>
  32 #include <lttng-share.h>
  33 #include <lttng/lttng.h>
  34 #include <lttngerr.h>
  35
  36 /* Socket to session daemon for communication */
  37 static int sessiond_socket;
  38 static char sessiond_sock_path[PATH_MAX];
  39
  40 /* Variables */
  41 static char *tracing_group;
  42 static int connected;
  43
  44 /*
  45  * Copy string from src to dst and enforce null terminated byte.
  46  */
  47 static void copy_string(char *dst, const char *src, size_t len)
  48 {
  49         if (src && dst) {
  50                 strncpy(dst, src, len);
  51                 /* Enforce the NULL terminated byte */
  52                 dst[len - 1] = '\0';
  53         } else if (dst) {
  54                 dst[0] = '\0';
  55         }
  56 }
  57
  58 /*
  59  * Copy domain to lttcomm_session_msg domain.
  60  *
  61  * If domain is unknown, default domain will be the kernel.
  62  */
  63 static void copy_lttng_domain(struct lttng_domain *dst, struct lttng_domain *src)
  64 {
  65         if (src && dst) {
  66                 switch (src->type) {
  67                         case LTTNG_DOMAIN_KERNEL:
  68                         case LTTNG_DOMAIN_UST:
  69                         case LTTNG_DOMAIN_UST_EXEC_NAME:
  70                         case LTTNG_DOMAIN_UST_PID:
  71                         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
  72                                 memcpy(dst, src, sizeof(struct lttng_domain));
  73                                 break;
  74                         default:
  75                                 dst->type = LTTNG_DOMAIN_KERNEL;
  76                                 break;
  77                 }
  78         }
  79 }
  80
  81 /*
  82  * Send lttcomm_session_msg to the session daemon.
  83  *
  84  * On success, return 0
  85  * On error, return error code
  86  */
  87 static int send_session_msg(struct lttcomm_session_msg *lsm)
  88 {
  89         int ret;
  90
  91         if (!connected) {
  92                 ret = -ENOTCONN;
  93                 goto end;
  94         }
  95
  96         ret = lttcomm_send_unix_sock(sessiond_socket, lsm,
  97                         sizeof(struct lttcomm_session_msg));
  98
  99 end:
 100         return ret;
 101 }
 102
 103 /*
 104  * Receive data from the sessiond socket.
 105  *
 106  * On success, return 0
 107  * On error, return recv() error code
 108  */
 109 static int recv_data_sessiond(void *buf, size_t len)
 110 {
 111         int ret;
 112
 113         if (!connected) {
 114                 ret = -ENOTCONN;
 115                 goto end;
 116         }
 117
 118         ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
 119
 120 end:
 121         return ret;
 122 }
 123
 124 /*
 125  *  Check if the specified group name exist.
 126  *
 127  *  If yes return 1, else return -1.
 128  */
 129 static int check_tracing_group(const char *grp_name)
 130 {
 131         struct group *grp_tracing;      /* no free(). See getgrnam(3) */
 132         gid_t *grp_list;
 133         int grp_list_size, grp_id, i;
 134         int ret = -1;
 135
 136         /* Get GID of group 'tracing' */
 137         grp_tracing = getgrnam(grp_name);
 138         if (grp_tracing == NULL) {
 139                 /* NULL means not found also. getgrnam(3) */
 140                 if (errno != 0) {
 141                         perror("getgrnam");
 142                 }
 143                 goto end;
 144         }
 145
 146         /* Get number of supplementary group IDs */
 147         grp_list_size = getgroups(0, NULL);
 148         if (grp_list_size < 0) {
 149                 perror("getgroups");
 150                 goto end;
 151         }
 152
 153         /* Alloc group list of the right size */
 154         grp_list = malloc(grp_list_size * sizeof(gid_t));
 155         if (!grp_list) {
 156                 ret = -1;
 157                 goto end;
 158         }
 159         grp_id = getgroups(grp_list_size, grp_list);
 160         if (grp_id < -1) {
 161                 perror("getgroups");
 162                 goto free_list;
 163         }
 164
 165         for (i = 0; i < grp_list_size; i++) {
 166                 if (grp_list[i] == grp_tracing->gr_gid) {
 167                         ret = 1;
 168                         break;
 169                 }
 170         }
 171
 172 free_list:
 173         free(grp_list);
 174
 175 end:
 176         return ret;
 177 }
 178
 179 /*
 180  * Try connect to session daemon with sock_path.
 181  *
 182  * Return 0 on success, else -1
 183  */
 184 static int try_connect_sessiond(const char *sock_path)
 185 {
 186         int ret;
 187
 188         /* If socket exist, we check if the daemon listens for connect. */
 189         ret = access(sock_path, F_OK);
 190         if (ret < 0) {
 191                 /* Not alive */
 192                 return -1;
 193         }
 194
 195         ret = lttcomm_connect_unix_sock(sock_path);
 196         if (ret < 0) {
 197                 /* Not alive */
 198                 return -1;
 199         }
 200
 201         ret = lttcomm_close_unix_sock(ret);
 202         if (ret < 0) {
 203                 perror("lttcomm_close_unix_sock");
 204         }
 205
 206         return 0;
 207 }
 208
 209 /*
 210  * Set sessiond socket path by putting it in the global sessiond_sock_path
 211  * variable.
 212  */
 213 static int set_session_daemon_path(void)
 214 {
 215         int ret;
 216         int in_tgroup = 0;      /* In tracing group */
 217         uid_t uid;
 218
 219         uid = getuid();
 220
 221         if (uid != 0) {
 222                 /* Are we in the tracing group ? */
 223                 in_tgroup = check_tracing_group(tracing_group);
 224         }
 225
 226         if (uid == 0) {
 227                 /* Root */
 228                 copy_string(sessiond_sock_path,
 229                                 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
 230                                 sizeof(sessiond_sock_path));
 231         } else if (in_tgroup) {
 232                 /* Tracing group */
 233                 copy_string(sessiond_sock_path,
 234                                 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
 235                                 sizeof(sessiond_sock_path));
 236
 237                 ret = try_connect_sessiond(sessiond_sock_path);
 238                 if (ret < 0) {
 239                         /* Global session daemon not available */
 240                         if (snprintf(sessiond_sock_path, sizeof(sessiond_sock_path),
 241                                                 DEFAULT_HOME_CLIENT_UNIX_SOCK,
 242                                                 getenv("HOME")) < 0) {
 243                                 return -ENOMEM;
 244                         }
 245                 }
 246         } else {
 247                 /* Not in tracing group and not root, default */
 248                 if (snprintf(sessiond_sock_path, PATH_MAX,
 249                                         DEFAULT_HOME_CLIENT_UNIX_SOCK,
 250                                         getenv("HOME")) < 0) {
 251                         return -ENOMEM;
 252                 }
 253         }
 254
 255         return 0;
 256 }
 257
 258 /*
 259  *  Connect to the LTTng session daemon.
 260  *
 261  *  On success, return 0. On error, return -1.
 262  */
 263 static int connect_sessiond(void)
 264 {
 265         int ret;
 266
 267         ret = set_session_daemon_path();
 268         if (ret < 0) {
 269                 return ret;
 270         }
 271
 272         /* Connect to the sesssion daemon */
 273         ret = lttcomm_connect_unix_sock(sessiond_sock_path);
 274         if (ret < 0) {
 275                 return ret;
 276         }
 277
 278         sessiond_socket = ret;
 279         connected = 1;
 280
 281         return 0;
 282 }
 283
 284 /*
 285  *  Clean disconnect the session daemon.
 286  */
 287 static int disconnect_sessiond(void)
 288 {
 289         int ret = 0;
 290
 291         if (connected) {
 292                 ret = lttcomm_close_unix_sock(sessiond_socket);
 293                 sessiond_socket = 0;
 294                 connected = 0;
 295         }
 296
 297         return ret;
 298 }
 299
 300 /*
 301  * Ask the session daemon a specific command and put the data into buf.
 302  *
 303  * Return size of data (only payload, not header).
 304  */
 305 static int ask_sessiond(struct lttcomm_session_msg *lsm, void **buf)
 306 {
 307         int ret;
 308         size_t size;
 309         void *data = NULL;
 310         struct lttcomm_lttng_msg llm;
 311
 312         ret = connect_sessiond();
 313         if (ret < 0) {
 314                 goto end;
 315         }
 316
 317         /* Send command to session daemon */
 318         ret = send_session_msg(lsm);
 319         if (ret < 0) {
 320                 goto end;
 321         }
 322
 323         /* Get header from data transmission */
 324         ret = recv_data_sessiond(&llm, sizeof(llm));
 325         if (ret < 0) {
 326                 goto end;
 327         }
 328
 329         /* Check error code if OK */
 330         if (llm.ret_code != LTTCOMM_OK) {
 331                 ret = -llm.ret_code;
 332                 goto end;
 333         }
 334
 335         size = llm.data_size;
 336         if (size == 0) {
 337                 ret = 0;
 338                 goto end;
 339         }
 340
 341         data = (void*) malloc(size);
 342
 343         /* Get payload data */
 344         ret = recv_data_sessiond(data, size);
 345         if (ret < 0) {
 346                 free(data);
 347                 goto end;
 348         }
 349
 350         /*
 351          * Extra protection not to dereference a NULL pointer. If buf is NULL at
 352          * this point, an error is returned and data is freed.
 353          */
 354         if (buf == NULL) {
 355                 ret = -1;
 356                 free(data);
 357                 goto end;
 358         }
 359
 360         *buf = data;
 361         ret = size;
 362
 363 end:
 364         disconnect_sessiond();
 365         return ret;
 366 }
 367
 368 /*
 369  * Create lttng handle and return pointer.
 370  */
 371 struct lttng_handle *lttng_create_handle(const char *session_name,
 372                 struct lttng_domain *domain)
 373 {
 374         struct lttng_handle *handle;
 375
 376         handle = malloc(sizeof(struct lttng_handle));
 377         if (handle == NULL) {
 378                 perror("malloc handle");
 379                 goto end;
 380         }
 381
 382         /* Copy session name */
 383         copy_string(handle->session_name, session_name,
 384                         sizeof(handle->session_name));
 385
 386         /* Copy lttng domain */
 387         copy_lttng_domain(&handle->domain, domain);
 388
 389 end:
 390         return handle;
 391 }
 392
 393 /*
 394  * Destroy handle by free(3) the pointer.
 395  */
 396 void lttng_destroy_handle(struct lttng_handle *handle)
 397 {
 398         if (handle) {
 399                 free(handle);
 400         }
 401 }
 402
 403 /*
 404  * Register an outside consumer.
 405  */
 406 int lttng_register_consumer(struct lttng_handle *handle,
 407                 const char *socket_path)
 408 {
 409         struct lttcomm_session_msg lsm;
 410
 411         lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
 412         copy_string(lsm.session.name, handle->session_name,
 413                         sizeof(lsm.session.name));
 414         copy_lttng_domain(&lsm.domain, &handle->domain);
 415
 416         copy_string(lsm.u.reg.path, socket_path, sizeof(lsm.u.reg.path));
 417
 418         return ask_sessiond(&lsm, NULL);
 419 }
 420
 421 /*
 422  *  Start tracing for all trace of the session.
 423  */
 424 int lttng_start_tracing(struct lttng_handle *handle)
 425 {
 426         struct lttcomm_session_msg lsm;
 427
 428         if (!handle) {
 429                 return -1;
 430         }
 431
 432         lsm.cmd_type = LTTNG_START_TRACE;
 433         copy_string(lsm.session.name, handle->session_name,
 434                         sizeof(lsm.session.name));
 435
 436         return ask_sessiond(&lsm, NULL);
 437 }
 438
 439 /*
 440  *  Stop tracing for all trace of the session.
 441  */
 442 int lttng_stop_tracing(struct lttng_handle *handle)
 443 {
 444         struct lttcomm_session_msg lsm;
 445
 446         lsm.cmd_type = LTTNG_STOP_TRACE;
 447         copy_string(lsm.session.name, handle->session_name,
 448                         sizeof(lsm.session.name));
 449
 450         return ask_sessiond(&lsm, NULL);
 451 }
 452
 453 /*
 454  * Add context to event or/and channel.
 455  */
 456 int lttng_add_context(struct lttng_handle *handle,
 457                 struct lttng_event_context *ctx, const char *event_name,
 458                 const char *channel_name)
 459 {
 460         struct lttcomm_session_msg lsm;
 461
 462         if (!handle) {
 463                 return -1;
 464         }
 465
 466         lsm.cmd_type = LTTNG_ADD_CONTEXT;
 467
 468         /* Copy channel name */
 469         copy_string(lsm.u.context.channel_name, channel_name,
 470                         sizeof(lsm.u.context.channel_name));
 471         /* Copy event name */
 472         copy_string(lsm.u.context.event_name, event_name,
 473                         sizeof(lsm.u.context.event_name));
 474
 475         copy_lttng_domain(&lsm.domain, &handle->domain);
 476
 477         if (ctx) {
 478                 memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
 479         }
 480
 481         copy_string(lsm.session.name, handle->session_name,
 482                         sizeof(lsm.session.name));
 483
 484         return ask_sessiond(&lsm, NULL);
 485 }
 486
 487 /*
 488  * Enable event
 489  */
 490 int lttng_enable_event(struct lttng_handle *handle,
 491                 struct lttng_event *ev, const char *channel_name)
 492 {
 493         struct lttcomm_session_msg lsm;
 494
 495         if (!handle) {
 496                 return -1;
 497         }
 498
 499         if (channel_name == NULL) {
 500                 copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME,
 501                                 sizeof(lsm.u.enable.channel_name));
 502         } else {
 503                 copy_string(lsm.u.enable.channel_name, channel_name,
 504                                 sizeof(lsm.u.enable.channel_name));
 505         }
 506
 507         copy_lttng_domain(&lsm.domain, &handle->domain);
 508
 509         if (ev) {
 510                 lsm.cmd_type = LTTNG_ENABLE_EVENT;
 511                 memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
 512         } else {
 513                 lsm.cmd_type = LTTNG_ENABLE_ALL_EVENT;
 514         }
 515
 516         copy_string(lsm.session.name, handle->session_name,
 517                         sizeof(lsm.session.name));
 518
 519         return ask_sessiond(&lsm, NULL);
 520 }
 521
 522 /*
 523  * Disable event of a channel and domain.
 524  */
 525 int lttng_disable_event(struct lttng_handle *handle, const char *name,
 526                 const char *channel_name)
 527 {
 528         struct lttcomm_session_msg lsm;
 529
 530         if (!handle) {
 531                 return -1;
 532         }
 533
 534         if (channel_name) {
 535                 copy_string(lsm.u.disable.channel_name, channel_name,
 536                                 sizeof(lsm.u.disable.channel_name));
 537         } else {
 538                 copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME,
 539                                 sizeof(lsm.u.disable.channel_name));
 540         }
 541
 542         copy_lttng_domain(&lsm.domain, &handle->domain);
 543
 544         if (name == NULL) {
 545                 copy_string(lsm.u.disable.name, name, sizeof(lsm.u.disable.name));
 546                 lsm.cmd_type = LTTNG_DISABLE_EVENT;
 547         } else {
 548                 lsm.cmd_type = LTTNG_DISABLE_ALL_EVENT;
 549         }
 550
 551         copy_string(lsm.session.name, handle->session_name,
 552                         sizeof(lsm.session.name));
 553
 554         return ask_sessiond(&lsm, NULL);
 555 }
 556
 557 /*
 558  * Enable channel per domain
 559  */
 560 int lttng_enable_channel(struct lttng_handle *handle,
 561                 struct lttng_channel *chan)
 562 {
 563         struct lttcomm_session_msg lsm;
 564
 565         if (!handle) {
 566                 return -1;
 567         }
 568
 569         if (chan) {
 570                 memcpy(&lsm.u.channel.chan, chan, sizeof(lsm.u.channel.chan));
 571         }
 572
 573         lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
 574
 575         copy_lttng_domain(&lsm.domain, &handle->domain);
 576
 577         copy_string(lsm.session.name, handle->session_name,
 578                         sizeof(lsm.session.name));
 579
 580         return ask_sessiond(&lsm, NULL);
 581 }
 582
 583 /*
 584  * All tracing will be stopped for registered events of the channel.
 585  */
 586 int lttng_disable_channel(struct lttng_handle *handle, const char *name)
 587 {
 588         struct lttcomm_session_msg lsm;
 589
 590         if (!handle) {
 591                 return -1;
 592         }
 593
 594         if (name) {
 595                 copy_string(lsm.u.disable.channel_name, name,
 596                                 sizeof(lsm.u.disable.channel_name));
 597         }
 598
 599         lsm.cmd_type = LTTNG_DISABLE_CHANNEL;
 600
 601         copy_lttng_domain(&lsm.domain, &handle->domain);
 602
 603         copy_string(lsm.session.name, handle->session_name,
 604                         sizeof(lsm.session.name));
 605
 606         return ask_sessiond(&lsm, NULL);
 607 }
 608
 609 /*
 610  * List all available tracepoints of domain.
 611  *
 612  * Return the size (bytes) of the list and set the events array.
 613  * On error, return negative value.
 614  */
 615 int lttng_list_tracepoints(struct lttng_handle *handle,
 616                 struct lttng_event **events)
 617 {
 618         int ret;
 619         struct lttcomm_session_msg lsm;
 620
 621         if (!handle) {
 622                 return -1;
 623         }
 624
 625         lsm.cmd_type = LTTNG_LIST_TRACEPOINTS;
 626         copy_lttng_domain(&lsm.domain, &handle->domain);
 627
 628         ret = ask_sessiond(&lsm, (void **) events);
 629         if (ret < 0) {
 630                 return ret;
 631         }
 632
 633         return ret / sizeof(struct lttng_event);
 634 }
 635
 636 /*
 637  *  Return a human readable string of code
 638  */
 639 const char *lttng_get_readable_code(int code)
 640 {
 641         if (code > -LTTCOMM_OK) {
 642                 return "Ended with errors";
 643         }
 644
 645         return lttcomm_get_readable_code(code);
 646 }
 647
 648 /*
 649  *  Create a brand new session using name.
 650  */
 651 int lttng_create_session(const char *name, const char *path)
 652 {
 653         struct lttcomm_session_msg lsm;
 654
 655         lsm.cmd_type = LTTNG_CREATE_SESSION;
 656         copy_string(lsm.session.name, name, sizeof(lsm.session.name));
 657         copy_string(lsm.session.path, path, sizeof(lsm.session.path));
 658
 659         return ask_sessiond(&lsm, NULL);
 660 }
 661
 662 /*
 663  *  Destroy session using name.
 664  */
 665 int lttng_destroy_session(struct lttng_handle *handle)
 666 {
 667         struct lttcomm_session_msg lsm;
 668
 669         if (!handle) {
 670                 return -1;
 671         }
 672
 673         lsm.cmd_type = LTTNG_DESTROY_SESSION;
 674         copy_string(lsm.session.name, handle->session_name,
 675                         sizeof(lsm.session.name));
 676
 677         return ask_sessiond(&lsm, NULL);
 678 }
 679
 680 /*
 681  *  Ask the session daemon for all available sessions.
 682  *
 683  *  Return number of session.
 684  *  On error, return negative value.
 685  */
 686 int lttng_list_sessions(struct lttng_session **sessions)
 687 {
 688         int ret;
 689         struct lttcomm_session_msg lsm;
 690
 691         lsm.cmd_type = LTTNG_LIST_SESSIONS;
 692         ret = ask_sessiond(&lsm, (void**) sessions);
 693         if (ret < 0) {
 694                 return ret;
 695         }
 696
 697         return ret / sizeof(struct lttng_session);
 698 }
 699
 700 /*
 701  * List domain of a session.
 702  */
 703 int lttng_list_domains(struct lttng_handle *handle,
 704                 struct lttng_domain **domains)
 705 {
 706         int ret;
 707         struct lttcomm_session_msg lsm;
 708
 709         if (!handle) {
 710                 return -1;
 711         }
 712
 713         lsm.cmd_type = LTTNG_LIST_DOMAINS;
 714
 715         copy_string(lsm.session.name, handle->session_name,
 716                         sizeof(lsm.session.name));
 717
 718         ret = ask_sessiond(&lsm, (void**) domains);
 719         if (ret < 0) {
 720                 return ret;
 721         }
 722
 723         return ret / sizeof(struct lttng_domain);
 724 }
 725
 726 /*
 727  * List channels of a session
 728  */
 729 int lttng_list_channels(struct lttng_handle *handle,
 730                 struct lttng_channel **channels)
 731 {
 732         int ret;
 733         struct lttcomm_session_msg lsm;
 734
 735         if (!handle) {
 736                 return -1;
 737         }
 738
 739         lsm.cmd_type = LTTNG_LIST_CHANNELS;
 740         copy_string(lsm.session.name, handle->session_name,
 741                         sizeof(lsm.session.name));
 742
 743         copy_lttng_domain(&lsm.domain, &handle->domain);
 744
 745         ret = ask_sessiond(&lsm, (void**) channels);
 746         if (ret < 0) {
 747                 return ret;
 748         }
 749
 750         return ret / sizeof(struct lttng_channel);
 751 }
 752
 753 /*
 754  * List events of a session channel.
 755  */
 756 int lttng_list_events(struct lttng_handle *handle,
 757                 const char *channel_name, struct lttng_event **events)
 758 {
 759         int ret;
 760         struct lttcomm_session_msg lsm;
 761
 762         if (!handle) {
 763                 return -1;
 764         }
 765
 766         lsm.cmd_type = LTTNG_LIST_EVENTS;
 767         copy_string(lsm.session.name, handle->session_name,
 768                         sizeof(lsm.session.name));
 769         copy_string(lsm.u.list.channel_name, channel_name,
 770                         sizeof(lsm.u.list.channel_name));
 771
 772         copy_lttng_domain(&lsm.domain, &handle->domain);
 773
 774         ret = ask_sessiond(&lsm, (void**) events);
 775         if (ret < 0) {
 776                 return ret;
 777         }
 778
 779         return ret / sizeof(struct lttng_event);
 780 }
 781
 782 /*
 783  *  lttng_set_tracing_group
 784  *
 785  *  Set tracing group variable with name. This function
 786  *  allocate memory pointed by tracing_group.
 787  */
 788 int lttng_set_tracing_group(const char *name)
 789 {
 790         if (asprintf(&tracing_group, "%s", name) < 0) {
 791                 return -ENOMEM;
 792         }
 793
 794         return 0;
 795 }
 796
 797 /*
 798  *  lttng_calibrate
 799  */
 800 int lttng_calibrate(struct lttng_handle *handle,
 801                 struct lttng_calibrate *calibrate)
 802 {
 803         struct lttcomm_session_msg lsm;
 804
 805         if (!handle) {
 806                 return -1;
 807         }
 808
 809         lsm.cmd_type = LTTNG_CALIBRATE;
 810         copy_lttng_domain(&lsm.domain, &handle->domain);
 811
 812         memcpy(&lsm.u.calibrate, calibrate, sizeof(lsm.u.calibrate));
 813
 814         return ask_sessiond(&lsm, NULL);
 815 }
 816
 817 /*
 818  * Check if session daemon is alive.
 819  *
 820  * Return 1 if alive or 0 if not.
 821  * On error return -1
 822  */
 823 int lttng_session_daemon_alive(void)
 824 {
 825         int ret;
 826
 827         ret = set_session_daemon_path();
 828         if (ret < 0) {
 829                 /* Error */
 830                 return ret;
 831         }
 832
 833         if (strlen(sessiond_sock_path) == 0) {
 834                 /* No socket path set. Weird error */
 835                 return -1;
 836         }
 837
 838         ret = try_connect_sessiond(sessiond_sock_path);
 839         if (ret < 0) {
 840                 /* Not alive */
 841                 return 0;
 842         }
 843
 844         /* Is alive */
 845         return 1;
 846 }
 847
 848 /*
 849  * lib constructor
 850  */
 851 static void __attribute__((constructor)) init()
 852 {
 853         /* Set default session group */
 854         lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
 855 }