src/lib/lttng-ctl/lttng-ctl.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 <common/sessiond-comm/sessiond-comm.h>
  32 #include <common/lttng-share.h>
  33 #include <common/lttngerr.h>
  34 #include <lttng/lttng.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_creds_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                 /* If client free with size 0 */
 338                 if (buf != NULL) {
 339                         *buf = NULL;
 340                 }
 341                 ret = 0;
 342                 goto end;
 343         }
 344
 345         data = (void*) malloc(size);
 346
 347         /* Get payload data */
 348         ret = recv_data_sessiond(data, size);
 349         if (ret < 0) {
 350                 free(data);
 351                 goto end;
 352         }
 353
 354         /*
 355          * Extra protection not to dereference a NULL pointer. If buf is NULL at
 356          * this point, an error is returned and data is freed.
 357          */
 358         if (buf == NULL) {
 359                 ret = -1;
 360                 free(data);
 361                 goto end;
 362         }
 363
 364         *buf = data;
 365         ret = size;
 366
 367 end:
 368         disconnect_sessiond();
 369         return ret;
 370 }
 371
 372 /*
 373  * Create lttng handle and return pointer.
 374  */
 375 struct lttng_handle *lttng_create_handle(const char *session_name,
 376                 struct lttng_domain *domain)
 377 {
 378         struct lttng_handle *handle;
 379
 380         handle = malloc(sizeof(struct lttng_handle));
 381         if (handle == NULL) {
 382                 perror("malloc handle");
 383                 goto end;
 384         }
 385
 386         /* Copy session name */
 387         copy_string(handle->session_name, session_name,
 388                         sizeof(handle->session_name));
 389
 390         /* Copy lttng domain */
 391         copy_lttng_domain(&handle->domain, domain);
 392
 393 end:
 394         return handle;
 395 }
 396
 397 /*
 398  * Destroy handle by free(3) the pointer.
 399  */
 400 void lttng_destroy_handle(struct lttng_handle *handle)
 401 {
 402         if (handle) {
 403                 free(handle);
 404         }
 405 }
 406
 407 /*
 408  * Register an outside consumer.
 409  */
 410 int lttng_register_consumer(struct lttng_handle *handle,
 411                 const char *socket_path)
 412 {
 413         struct lttcomm_session_msg lsm;
 414
 415         lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
 416         copy_string(lsm.session.name, handle->session_name,
 417                         sizeof(lsm.session.name));
 418         copy_lttng_domain(&lsm.domain, &handle->domain);
 419
 420         copy_string(lsm.u.reg.path, socket_path, sizeof(lsm.u.reg.path));
 421
 422         return ask_sessiond(&lsm, NULL);
 423 }
 424
 425 /*
 426  *  Start tracing for all trace of the session.
 427  */
 428 int lttng_start_tracing(const char *session_name)
 429 {
 430         struct lttcomm_session_msg lsm;
 431
 432         if (session_name == NULL) {
 433                 return -1;
 434         }
 435
 436         lsm.cmd_type = LTTNG_START_TRACE;
 437
 438         copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
 439
 440         return ask_sessiond(&lsm, NULL);
 441 }
 442
 443 /*
 444  *  Stop tracing for all trace of the session.
 445  */
 446 int lttng_stop_tracing(const char *session_name)
 447 {
 448         struct lttcomm_session_msg lsm;
 449
 450         if (session_name == NULL) {
 451                 return -1;
 452         }
 453
 454         lsm.cmd_type = LTTNG_STOP_TRACE;
 455
 456         copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
 457
 458         return ask_sessiond(&lsm, NULL);
 459 }
 460
 461 /*
 462  * Add context to event or/and channel.
 463  */
 464 int lttng_add_context(struct lttng_handle *handle,
 465                 struct lttng_event_context *ctx, const char *event_name,
 466                 const char *channel_name)
 467 {
 468         struct lttcomm_session_msg lsm;
 469
 470         /* Safety check. Both are mandatory */
 471         if (handle == NULL || ctx == NULL) {
 472                 return -1;
 473         }
 474
 475         lsm.cmd_type = LTTNG_ADD_CONTEXT;
 476
 477         /* Copy channel name */
 478         copy_string(lsm.u.context.channel_name, channel_name,
 479                         sizeof(lsm.u.context.channel_name));
 480         /* Copy event name */
 481         copy_string(lsm.u.context.event_name, event_name,
 482                         sizeof(lsm.u.context.event_name));
 483
 484         copy_lttng_domain(&lsm.domain, &handle->domain);
 485
 486         memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
 487
 488         copy_string(lsm.session.name, handle->session_name,
 489                         sizeof(lsm.session.name));
 490
 491         return ask_sessiond(&lsm, NULL);
 492 }
 493
 494 /*
 495  * Enable event
 496  */
 497 int lttng_enable_event(struct lttng_handle *handle,
 498                 struct lttng_event *ev, const char *channel_name)
 499 {
 500         struct lttcomm_session_msg lsm;
 501
 502         if (handle == NULL || ev == NULL) {
 503                 return -1;
 504         }
 505
 506         /* If no channel name, we put the default name */
 507         if (channel_name == NULL) {
 508                 copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME,
 509                                 sizeof(lsm.u.enable.channel_name));
 510         } else {
 511                 copy_string(lsm.u.enable.channel_name, channel_name,
 512                                 sizeof(lsm.u.enable.channel_name));
 513         }
 514
 515         copy_lttng_domain(&lsm.domain, &handle->domain);
 516
 517         if (ev->name[0] != '\0') {
 518                 lsm.cmd_type = LTTNG_ENABLE_EVENT;
 519         } else {
 520                 lsm.cmd_type = LTTNG_ENABLE_ALL_EVENT;
 521         }
 522         memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
 523
 524         copy_string(lsm.session.name, handle->session_name,
 525                         sizeof(lsm.session.name));
 526
 527         return ask_sessiond(&lsm, NULL);
 528 }
 529
 530 /*
 531  * Disable event of a channel and domain.
 532  */
 533 int lttng_disable_event(struct lttng_handle *handle, const char *name,
 534                 const char *channel_name)
 535 {
 536         struct lttcomm_session_msg lsm;
 537
 538         if (handle == NULL) {
 539                 return -1;
 540         }
 541
 542         if (channel_name) {
 543                 copy_string(lsm.u.disable.channel_name, channel_name,
 544                                 sizeof(lsm.u.disable.channel_name));
 545         } else {
 546                 copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME,
 547                                 sizeof(lsm.u.disable.channel_name));
 548         }
 549
 550         copy_lttng_domain(&lsm.domain, &handle->domain);
 551
 552         if (name != NULL) {
 553                 copy_string(lsm.u.disable.name, name, sizeof(lsm.u.disable.name));
 554                 lsm.cmd_type = LTTNG_DISABLE_EVENT;
 555         } else {
 556                 lsm.cmd_type = LTTNG_DISABLE_ALL_EVENT;
 557         }
 558
 559         copy_string(lsm.session.name, handle->session_name,
 560                         sizeof(lsm.session.name));
 561
 562         return ask_sessiond(&lsm, NULL);
 563 }
 564
 565 /*
 566  * Enable channel per domain
 567  */
 568 int lttng_enable_channel(struct lttng_handle *handle,
 569                 struct lttng_channel *chan)
 570 {
 571         struct lttcomm_session_msg lsm;
 572
 573         /*
 574          * NULL arguments are forbidden. No default values.
 575          */
 576         if (handle == NULL || chan == NULL) {
 577                 return -1;
 578         }
 579
 580         memcpy(&lsm.u.channel.chan, chan, sizeof(lsm.u.channel.chan));
 581
 582         lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
 583
 584         copy_lttng_domain(&lsm.domain, &handle->domain);
 585
 586         copy_string(lsm.session.name, handle->session_name,
 587                         sizeof(lsm.session.name));
 588
 589         return ask_sessiond(&lsm, NULL);
 590 }
 591
 592 /*
 593  * All tracing will be stopped for registered events of the channel.
 594  */
 595 int lttng_disable_channel(struct lttng_handle *handle, const char *name)
 596 {
 597         struct lttcomm_session_msg lsm;
 598
 599         /* Safety check. Both are mandatory */
 600         if (handle == NULL || name == NULL) {
 601                 return -1;
 602         }
 603
 604         lsm.cmd_type = LTTNG_DISABLE_CHANNEL;
 605
 606         copy_string(lsm.u.disable.channel_name, name,
 607                         sizeof(lsm.u.disable.channel_name));
 608
 609         copy_lttng_domain(&lsm.domain, &handle->domain);
 610
 611         copy_string(lsm.session.name, handle->session_name,
 612                         sizeof(lsm.session.name));
 613
 614         return ask_sessiond(&lsm, NULL);
 615 }
 616
 617 /*
 618  * List all available tracepoints of domain.
 619  *
 620  * Return the size (bytes) of the list and set the events array.
 621  * On error, return negative value.
 622  */
 623 int lttng_list_tracepoints(struct lttng_handle *handle,
 624                 struct lttng_event **events)
 625 {
 626         int ret;
 627         struct lttcomm_session_msg lsm;
 628
 629         if (handle == NULL) {
 630                 return -1;
 631         }
 632
 633         lsm.cmd_type = LTTNG_LIST_TRACEPOINTS;
 634         copy_lttng_domain(&lsm.domain, &handle->domain);
 635
 636         ret = ask_sessiond(&lsm, (void **) events);
 637         if (ret < 0) {
 638                 return ret;
 639         }
 640
 641         return ret / sizeof(struct lttng_event);
 642 }
 643
 644 /*
 645  *  Return a human readable string of code
 646  */
 647 const char *lttng_strerror(int code)
 648 {
 649         if (code > -LTTCOMM_OK) {
 650                 return "Ended with errors";
 651         }
 652
 653         return lttcomm_get_readable_code(code);
 654 }
 655
 656 /*
 657  *  Create a brand new session using name.
 658  */
 659 int lttng_create_session(const char *name, const char *path)
 660 {
 661         struct lttcomm_session_msg lsm;
 662
 663         lsm.cmd_type = LTTNG_CREATE_SESSION;
 664         copy_string(lsm.session.name, name, sizeof(lsm.session.name));
 665         copy_string(lsm.session.path, path, sizeof(lsm.session.path));
 666
 667         return ask_sessiond(&lsm, NULL);
 668 }
 669
 670 /*
 671  *  Destroy session using name.
 672  */
 673 int lttng_destroy_session(const char *session_name)
 674 {
 675         struct lttcomm_session_msg lsm;
 676
 677         if (session_name == NULL) {
 678                 return -1;
 679         }
 680
 681         lsm.cmd_type = LTTNG_DESTROY_SESSION;
 682
 683         copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
 684
 685         return ask_sessiond(&lsm, NULL);
 686 }
 687
 688 /*
 689  *  Ask the session daemon for all available sessions.
 690  *
 691  *  Return number of session.
 692  *  On error, return negative value.
 693  */
 694 int lttng_list_sessions(struct lttng_session **sessions)
 695 {
 696         int ret;
 697         struct lttcomm_session_msg lsm;
 698
 699         lsm.cmd_type = LTTNG_LIST_SESSIONS;
 700         ret = ask_sessiond(&lsm, (void**) sessions);
 701         if (ret < 0) {
 702                 return ret;
 703         }
 704
 705         return ret / sizeof(struct lttng_session);
 706 }
 707
 708 /*
 709  * List domain of a session.
 710  */
 711 int lttng_list_domains(const char *session_name,
 712                 struct lttng_domain **domains)
 713 {
 714         int ret;
 715         struct lttcomm_session_msg lsm;
 716
 717         if (session_name == NULL) {
 718                 return -1;
 719         }
 720
 721         lsm.cmd_type = LTTNG_LIST_DOMAINS;
 722
 723         copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
 724
 725         ret = ask_sessiond(&lsm, (void**) domains);
 726         if (ret < 0) {
 727                 return ret;
 728         }
 729
 730         return ret / sizeof(struct lttng_domain);
 731 }
 732
 733 /*
 734  * List channels of a session
 735  */
 736 int lttng_list_channels(struct lttng_handle *handle,
 737                 struct lttng_channel **channels)
 738 {
 739         int ret;
 740         struct lttcomm_session_msg lsm;
 741
 742         if (handle == NULL) {
 743                 return -1;
 744         }
 745
 746         lsm.cmd_type = LTTNG_LIST_CHANNELS;
 747         copy_string(lsm.session.name, handle->session_name,
 748                         sizeof(lsm.session.name));
 749
 750         copy_lttng_domain(&lsm.domain, &handle->domain);
 751
 752         ret = ask_sessiond(&lsm, (void**) channels);
 753         if (ret < 0) {
 754                 return ret;
 755         }
 756
 757         return ret / sizeof(struct lttng_channel);
 758 }
 759
 760 /*
 761  * List events of a session channel.
 762  */
 763 int lttng_list_events(struct lttng_handle *handle,
 764                 const char *channel_name, struct lttng_event **events)
 765 {
 766         int ret;
 767         struct lttcomm_session_msg lsm;
 768
 769         /* Safety check. An handle and channel name are mandatory */
 770         if (handle == NULL || channel_name == NULL) {
 771                 return -1;
 772         }
 773
 774         lsm.cmd_type = LTTNG_LIST_EVENTS;
 775         copy_string(lsm.session.name, handle->session_name,
 776                         sizeof(lsm.session.name));
 777         copy_string(lsm.u.list.channel_name, channel_name,
 778                         sizeof(lsm.u.list.channel_name));
 779
 780         copy_lttng_domain(&lsm.domain, &handle->domain);
 781
 782         ret = ask_sessiond(&lsm, (void**) events);
 783         if (ret < 0) {
 784                 return ret;
 785         }
 786
 787         return ret / sizeof(struct lttng_event);
 788 }
 789
 790 /*
 791  * Set tracing group variable with name. This function allocate memory pointed
 792  * by tracing_group.
 793  */
 794 int lttng_set_tracing_group(const char *name)
 795 {
 796         if (name == NULL) {
 797                 return -1;
 798         }
 799
 800         if (asprintf(&tracing_group, "%s", name) < 0) {
 801                 return -ENOMEM;
 802         }
 803
 804         return 0;
 805 }
 806
 807 /*
 808  *  lttng_calibrate
 809  */
 810 int lttng_calibrate(struct lttng_handle *handle,
 811                 struct lttng_calibrate *calibrate)
 812 {
 813         struct lttcomm_session_msg lsm;
 814
 815         /* Safety check. NULL pointer are forbidden */
 816         if (handle == NULL || calibrate == NULL) {
 817                 return -1;
 818         }
 819
 820         lsm.cmd_type = LTTNG_CALIBRATE;
 821         copy_lttng_domain(&lsm.domain, &handle->domain);
 822
 823         memcpy(&lsm.u.calibrate, calibrate, sizeof(lsm.u.calibrate));
 824
 825         return ask_sessiond(&lsm, NULL);
 826 }
 827
 828 /*
 829  * Set default channel attributes.
 830  */
 831 void lttng_channel_set_default_attr(struct lttng_domain *domain,
 832                 struct lttng_channel_attr *attr)
 833 {
 834         /* Safety check */
 835         if (attr == NULL || domain == NULL) {
 836                 return;
 837         }
 838
 839         switch (domain->type) {
 840         case LTTNG_DOMAIN_KERNEL:
 841                 attr->overwrite = DEFAULT_CHANNEL_OVERWRITE;
 842                 attr->switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
 843                 attr->read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
 844
 845                 attr->subbuf_size = DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE;
 846                 attr->num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
 847                 attr->output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 848                 break;
 849         case LTTNG_DOMAIN_UST:
 850         case LTTNG_DOMAIN_UST_EXEC_NAME:
 851         case LTTNG_DOMAIN_UST_PID:
 852         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 853                 attr->overwrite = DEFAULT_CHANNEL_OVERWRITE;
 854                 attr->switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
 855                 attr->read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
 856
 857                 attr->subbuf_size = DEFAULT_UST_CHANNEL_SUBBUF_SIZE;
 858                 attr->num_subbuf = DEFAULT_UST_CHANNEL_SUBBUF_NUM;
 859                 attr->output = DEFAULT_UST_CHANNEL_OUTPUT;
 860                 break;
 861         default:
 862                 /* Default behavior */
 863                 memset(attr, 0, sizeof(struct lttng_channel_attr));
 864                 break;
 865         }
 866 }
 867
 868 /*
 869  * Check if session daemon is alive.
 870  *
 871  * Return 1 if alive or 0 if not.
 872  * On error return -1
 873  */
 874 int lttng_session_daemon_alive(void)
 875 {
 876         int ret;
 877
 878         ret = set_session_daemon_path();
 879         if (ret < 0) {
 880                 /* Error */
 881                 return ret;
 882         }
 883
 884         if (strlen(sessiond_sock_path) == 0) {
 885                 /* No socket path set. Weird error */
 886                 return -1;
 887         }
 888
 889         ret = try_connect_sessiond(sessiond_sock_path);
 890         if (ret < 0) {
 891                 /* Not alive */
 892                 return 0;
 893         }
 894
 895         /* Is alive */
 896         return 1;
 897 }
 898
 899 /*
 900  * lib constructor
 901  */
 902 static void __attribute__((constructor)) init()
 903 {
 904         /* Set default session group */
 905         lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
 906 }