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         grp_id = getgroups(grp_list_size, grp_list);
 156         if (grp_id < -1) {
 157                 perror("getgroups");
 158                 goto free_list;
 159         }
 160
 161         for (i = 0; i < grp_list_size; i++) {
 162                 if (grp_list[i] == grp_tracing->gr_gid) {
 163                         ret = 1;
 164                         break;
 165                 }
 166         }
 167
 168 free_list:
 169         free(grp_list);
 170
 171 end:
 172         return ret;
 173 }
 174
 175 /*
 176  * Try connect to session daemon with sock_path.
 177  *
 178  * Return 0 on success, else -1
 179  */
 180 static int try_connect_sessiond(const char *sock_path)
 181 {
 182         int ret;
 183
 184         /* If socket exist, we check if the daemon listens for connect. */
 185         ret = access(sock_path, F_OK);
 186         if (ret < 0) {
 187                 /* Not alive */
 188                 return -1;
 189         }
 190
 191         ret = lttcomm_connect_unix_sock(sock_path);
 192         if (ret < 0) {
 193                 /* Not alive */
 194                 return -1;
 195         }
 196
 197         ret = lttcomm_close_unix_sock(ret);
 198         if (ret < 0) {
 199                 perror("lttcomm_close_unix_sock");
 200         }
 201
 202         return 0;
 203 }
 204
 205 /*
 206  * Set sessiond socket path by putting it in the global sessiond_sock_path
 207  * variable.
 208  */
 209 static int set_session_daemon_path(void)
 210 {
 211         int ret;
 212         int in_tgroup = 0;      /* In tracing group */
 213         uid_t uid;
 214
 215         uid = getuid();
 216
 217         if (uid != 0) {
 218                 /* Are we in the tracing group ? */
 219                 in_tgroup = check_tracing_group(tracing_group);
 220         }
 221
 222         if (uid == 0) {
 223                 /* Root */
 224                 copy_string(sessiond_sock_path,
 225                                 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
 226                                 sizeof(sessiond_sock_path));
 227         } else if (in_tgroup) {
 228                 /* Tracing group */
 229                 copy_string(sessiond_sock_path,
 230                                 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
 231                                 sizeof(sessiond_sock_path));
 232
 233                 ret = try_connect_sessiond(sessiond_sock_path);
 234                 if (ret < 0) {
 235                         /* Global session daemon not available */
 236                         if (snprintf(sessiond_sock_path, sizeof(sessiond_sock_path),
 237                                                 DEFAULT_HOME_CLIENT_UNIX_SOCK,
 238                                                 getenv("HOME")) < 0) {
 239                                 return -ENOMEM;
 240                         }
 241                 }
 242         } else {
 243                 /* Not in tracing group and not root, default */
 244                 if (snprintf(sessiond_sock_path, PATH_MAX,
 245                                         DEFAULT_HOME_CLIENT_UNIX_SOCK,
 246                                         getenv("HOME")) < 0) {
 247                         return -ENOMEM;
 248                 }
 249         }
 250
 251         return 0;
 252 }
 253
 254 /*
 255  *  Connect to the LTTng session daemon.
 256  *
 257  *  On success, return 0. On error, return -1.
 258  */
 259 static int connect_sessiond(void)
 260 {
 261         int ret;
 262
 263         ret = set_session_daemon_path();
 264         if (ret < 0) {
 265                 return ret;
 266         }
 267
 268         /* Connect to the sesssion daemon */
 269         ret = lttcomm_connect_unix_sock(sessiond_sock_path);
 270         if (ret < 0) {
 271                 return ret;
 272         }
 273
 274         sessiond_socket = ret;
 275         connected = 1;
 276
 277         return 0;
 278 }
 279
 280 /*
 281  *  Clean disconnect the session daemon.
 282  */
 283 static int disconnect_sessiond(void)
 284 {
 285         int ret = 0;
 286
 287         if (connected) {
 288                 ret = lttcomm_close_unix_sock(sessiond_socket);
 289                 sessiond_socket = 0;
 290                 connected = 0;
 291         }
 292
 293         return ret;
 294 }
 295
 296 /*
 297  * Ask the session daemon a specific command and put the data into buf.
 298  *
 299  * Return size of data (only payload, not header).
 300  */
 301 static int ask_sessiond(struct lttcomm_session_msg *lsm, void **buf)
 302 {
 303         int ret;
 304         size_t size;
 305         void *data = NULL;
 306         struct lttcomm_lttng_msg llm;
 307
 308         ret = connect_sessiond();
 309         if (ret < 0) {
 310                 goto end;
 311         }
 312
 313         /* Send command to session daemon */
 314         ret = send_session_msg(lsm);
 315         if (ret < 0) {
 316                 goto end;
 317         }
 318
 319         /* Get header from data transmission */
 320         ret = recv_data_sessiond(&llm, sizeof(llm));
 321         if (ret < 0) {
 322                 goto end;
 323         }
 324
 325         /* Check error code if OK */
 326         if (llm.ret_code != LTTCOMM_OK) {
 327                 ret = -llm.ret_code;
 328                 goto end;
 329         }
 330
 331         size = llm.data_size;
 332         if (size == 0) {
 333                 ret = 0;
 334                 goto end;
 335         }
 336
 337         data = (void*) malloc(size);
 338
 339         /* Get payload data */
 340         ret = recv_data_sessiond(data, size);
 341         if (ret < 0) {
 342                 free(data);
 343                 goto end;
 344         }
 345
 346         /*
 347          * Extra protection not to dereference a NULL pointer. If buf is NULL at
 348          * this point, an error is returned and data is freed.
 349          */
 350         if (buf == NULL) {
 351                 ret = -1;
 352                 free(data);
 353                 goto end;
 354         }
 355
 356         *buf = data;
 357         ret = size;
 358
 359 end:
 360         disconnect_sessiond();
 361         return ret;
 362 }
 363
 364 /*
 365  * Create lttng handle and return pointer.
 366  */
 367 struct lttng_handle *lttng_create_handle(const char *session_name,
 368                 struct lttng_domain *domain)
 369 {
 370         struct lttng_handle *handle;
 371
 372         handle = malloc(sizeof(struct lttng_handle));
 373         if (handle == NULL) {
 374                 perror("malloc handle");
 375                 goto end;
 376         }
 377
 378         /* Copy session name */
 379         copy_string(handle->session_name, session_name,
 380                         sizeof(handle->session_name));
 381
 382         /* Copy lttng domain */
 383         copy_lttng_domain(&handle->domain, domain);
 384
 385 end:
 386         return handle;
 387 }
 388
 389 /*
 390  * Destroy handle by free(3) the pointer.
 391  */
 392 void lttng_destroy_handle(struct lttng_handle *handle)
 393 {
 394         if (handle) {
 395                 free(handle);
 396         }
 397 }
 398
 399 /*
 400  * Register an outside consumer.
 401  */
 402 int lttng_register_consumer(struct lttng_handle *handle,
 403                 const char *socket_path)
 404 {
 405         struct lttcomm_session_msg lsm;
 406
 407         lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
 408         copy_string(lsm.session.name, handle->session_name,
 409                         sizeof(lsm.session.name));
 410         copy_lttng_domain(&lsm.domain, &handle->domain);
 411
 412         copy_string(lsm.u.reg.path, socket_path, sizeof(lsm.u.reg.path));
 413
 414         return ask_sessiond(&lsm, NULL);
 415 }
 416
 417 /*
 418  *  Start tracing for all trace of the session.
 419  */
 420 int lttng_start_tracing(struct lttng_handle *handle)
 421 {
 422         struct lttcomm_session_msg lsm;
 423
 424         if (!handle) {
 425                 return -1;
 426         }
 427
 428         lsm.cmd_type = LTTNG_START_TRACE;
 429         copy_string(lsm.session.name, handle->session_name,
 430                         sizeof(lsm.session.name));
 431
 432         return ask_sessiond(&lsm, NULL);
 433 }
 434
 435 /*
 436  *  Stop tracing for all trace of the session.
 437  */
 438 int lttng_stop_tracing(struct lttng_handle *handle)
 439 {
 440         struct lttcomm_session_msg lsm;
 441
 442         lsm.cmd_type = LTTNG_STOP_TRACE;
 443         copy_string(lsm.session.name, handle->session_name,
 444                         sizeof(lsm.session.name));
 445
 446         return ask_sessiond(&lsm, NULL);
 447 }
 448
 449 /*
 450  * Add context to event or/and channel.
 451  */
 452 int lttng_add_context(struct lttng_handle *handle,
 453                 struct lttng_event_context *ctx, const char *event_name,
 454                 const char *channel_name)
 455 {
 456         struct lttcomm_session_msg lsm;
 457
 458         if (!handle) {
 459                 return -1;
 460         }
 461
 462         lsm.cmd_type = LTTNG_ADD_CONTEXT;
 463
 464         /* Copy channel name */
 465         copy_string(lsm.u.context.channel_name, channel_name,
 466                         sizeof(lsm.u.context.channel_name));
 467         /* Copy event name */
 468         copy_string(lsm.u.context.event_name, event_name,
 469                         sizeof(lsm.u.context.event_name));
 470
 471         copy_lttng_domain(&lsm.domain, &handle->domain);
 472
 473         if (ctx) {
 474                 memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
 475         }
 476
 477         copy_string(lsm.session.name, handle->session_name,
 478                         sizeof(lsm.session.name));
 479
 480         return ask_sessiond(&lsm, NULL);
 481 }
 482
 483 /*
 484  * Enable event
 485  */
 486 int lttng_enable_event(struct lttng_handle *handle,
 487                 struct lttng_event *ev, const char *channel_name)
 488 {
 489         struct lttcomm_session_msg lsm;
 490
 491         if (!handle) {
 492                 return -1;
 493         }
 494
 495         if (channel_name == NULL) {
 496                 copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME,
 497                                 sizeof(lsm.u.enable.channel_name));
 498         } else {
 499                 copy_string(lsm.u.enable.channel_name, channel_name,
 500                                 sizeof(lsm.u.enable.channel_name));
 501         }
 502
 503         copy_lttng_domain(&lsm.domain, &handle->domain);
 504
 505         if (ev) {
 506                 lsm.cmd_type = LTTNG_ENABLE_EVENT;
 507                 memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
 508         } else {
 509                 lsm.cmd_type = LTTNG_ENABLE_ALL_EVENT;
 510         }
 511
 512         copy_string(lsm.session.name, handle->session_name,
 513                         sizeof(lsm.session.name));
 514
 515         return ask_sessiond(&lsm, NULL);
 516 }
 517
 518 /*
 519  * Disable event of a channel and domain.
 520  */
 521 int lttng_disable_event(struct lttng_handle *handle, const char *name,
 522                 const char *channel_name)
 523 {
 524         struct lttcomm_session_msg lsm;
 525
 526         if (!handle) {
 527                 return -1;
 528         }
 529
 530         if (channel_name) {
 531                 copy_string(lsm.u.disable.channel_name, channel_name,
 532                                 sizeof(lsm.u.disable.channel_name));
 533         } else {
 534                 copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME,
 535                                 sizeof(lsm.u.disable.channel_name));
 536         }
 537
 538         copy_lttng_domain(&lsm.domain, &handle->domain);
 539
 540         if (name == NULL) {
 541                 copy_string(lsm.u.disable.name, name, sizeof(lsm.u.disable.name));
 542                 lsm.cmd_type = LTTNG_DISABLE_EVENT;
 543         } else {
 544                 lsm.cmd_type = LTTNG_DISABLE_ALL_EVENT;
 545         }
 546
 547         copy_string(lsm.session.name, handle->session_name,
 548                         sizeof(lsm.session.name));
 549
 550         return ask_sessiond(&lsm, NULL);
 551 }
 552
 553 /*
 554  * Enable channel per domain
 555  */
 556 int lttng_enable_channel(struct lttng_handle *handle,
 557                 struct lttng_channel *chan)
 558 {
 559         struct lttcomm_session_msg lsm;
 560
 561         if (!handle) {
 562                 return -1;
 563         }
 564
 565         if (chan) {
 566                 memcpy(&lsm.u.channel.chan, chan, sizeof(lsm.u.channel.chan));
 567         }
 568
 569         lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
 570
 571         copy_lttng_domain(&lsm.domain, &handle->domain);
 572
 573         copy_string(lsm.session.name, handle->session_name,
 574                         sizeof(lsm.session.name));
 575
 576         return ask_sessiond(&lsm, NULL);
 577 }
 578
 579 /*
 580  * All tracing will be stopped for registered events of the channel.
 581  */
 582 int lttng_disable_channel(struct lttng_handle *handle, const char *name)
 583 {
 584         struct lttcomm_session_msg lsm;
 585
 586         if (!handle) {
 587                 return -1;
 588         }
 589
 590         if (name) {
 591                 copy_string(lsm.u.disable.channel_name, name,
 592                                 sizeof(lsm.u.disable.channel_name));
 593         }
 594
 595         lsm.cmd_type = LTTNG_DISABLE_CHANNEL;
 596
 597         copy_lttng_domain(&lsm.domain, &handle->domain);
 598
 599         copy_string(lsm.session.name, handle->session_name,
 600                         sizeof(lsm.session.name));
 601
 602         return ask_sessiond(&lsm, NULL);
 603 }
 604
 605 /*
 606  * List all available tracepoints of domain.
 607  *
 608  * Return the size (bytes) of the list and set the events array.
 609  * On error, return negative value.
 610  */
 611 int lttng_list_tracepoints(struct lttng_handle *handle,
 612                 struct lttng_event **events)
 613 {
 614         int ret;
 615         struct lttcomm_session_msg lsm;
 616
 617         if (!handle) {
 618                 return -1;
 619         }
 620
 621         lsm.cmd_type = LTTNG_LIST_TRACEPOINTS;
 622         copy_lttng_domain(&lsm.domain, &handle->domain);
 623
 624         ret = ask_sessiond(&lsm, (void **) events);
 625         if (ret < 0) {
 626                 return ret;
 627         }
 628
 629         return ret / sizeof(struct lttng_event);
 630 }
 631
 632 /*
 633  *  Return a human readable string of code
 634  */
 635 const char *lttng_get_readable_code(int code)
 636 {
 637         if (code > -LTTCOMM_OK) {
 638                 return "Ended with errors";
 639         }
 640
 641         return lttcomm_get_readable_code(code);
 642 }
 643
 644 /*
 645  *  Create a brand new session using name.
 646  */
 647 int lttng_create_session(const char *name, const char *path)
 648 {
 649         struct lttcomm_session_msg lsm;
 650
 651         lsm.cmd_type = LTTNG_CREATE_SESSION;
 652         copy_string(lsm.session.name, name, sizeof(lsm.session.name));
 653         copy_string(lsm.session.path, path, sizeof(lsm.session.path));
 654
 655         return ask_sessiond(&lsm, NULL);
 656 }
 657
 658 /*
 659  *  Destroy session using name.
 660  */
 661 int lttng_destroy_session(struct lttng_handle *handle)
 662 {
 663         struct lttcomm_session_msg lsm;
 664
 665         if (!handle) {
 666                 return -1;
 667         }
 668
 669         lsm.cmd_type = LTTNG_DESTROY_SESSION;
 670         copy_string(lsm.session.name, handle->session_name,
 671                         sizeof(lsm.session.name));
 672
 673         return ask_sessiond(&lsm, NULL);
 674 }
 675
 676 /*
 677  *  Ask the session daemon for all available sessions.
 678  *
 679  *  Return number of session.
 680  *  On error, return negative value.
 681  */
 682 int lttng_list_sessions(struct lttng_session **sessions)
 683 {
 684         int ret;
 685         struct lttcomm_session_msg lsm;
 686
 687         lsm.cmd_type = LTTNG_LIST_SESSIONS;
 688         ret = ask_sessiond(&lsm, (void**) sessions);
 689         if (ret < 0) {
 690                 return ret;
 691         }
 692
 693         return ret / sizeof(struct lttng_session);
 694 }
 695
 696 /*
 697  * List domain of a session.
 698  */
 699 int lttng_list_domains(struct lttng_handle *handle,
 700                 struct lttng_domain **domains)
 701 {
 702         int ret;
 703         struct lttcomm_session_msg lsm;
 704
 705         if (!handle) {
 706                 return -1;
 707         }
 708
 709         lsm.cmd_type = LTTNG_LIST_DOMAINS;
 710
 711         copy_string(lsm.session.name, handle->session_name,
 712                         sizeof(lsm.session.name));
 713
 714         ret = ask_sessiond(&lsm, (void**) domains);
 715         if (ret < 0) {
 716                 return ret;
 717         }
 718
 719         return ret / sizeof(struct lttng_domain);
 720 }
 721
 722 /*
 723  * List channels of a session
 724  */
 725 int lttng_list_channels(struct lttng_handle *handle,
 726                 struct lttng_channel **channels)
 727 {
 728         int ret;
 729         struct lttcomm_session_msg lsm;
 730
 731         if (!handle) {
 732                 return -1;
 733         }
 734
 735         lsm.cmd_type = LTTNG_LIST_CHANNELS;
 736         copy_string(lsm.session.name, handle->session_name,
 737                         sizeof(lsm.session.name));
 738
 739         copy_lttng_domain(&lsm.domain, &handle->domain);
 740
 741         ret = ask_sessiond(&lsm, (void**) channels);
 742         if (ret < 0) {
 743                 return ret;
 744         }
 745
 746         return ret / sizeof(struct lttng_channel);
 747 }
 748
 749 /*
 750  * List events of a session channel.
 751  */
 752 int lttng_list_events(struct lttng_handle *handle,
 753                 const char *channel_name, struct lttng_event **events)
 754 {
 755         int ret;
 756         struct lttcomm_session_msg lsm;
 757
 758         if (!handle) {
 759                 return -1;
 760         }
 761
 762         lsm.cmd_type = LTTNG_LIST_EVENTS;
 763         copy_string(lsm.session.name, handle->session_name,
 764                         sizeof(lsm.session.name));
 765         copy_string(lsm.u.list.channel_name, channel_name,
 766                         sizeof(lsm.u.list.channel_name));
 767
 768         copy_lttng_domain(&lsm.domain, &handle->domain);
 769
 770         ret = ask_sessiond(&lsm, (void**) events);
 771         if (ret < 0) {
 772                 return ret;
 773         }
 774
 775         return ret / sizeof(struct lttng_event);
 776 }
 777
 778 /*
 779  *  lttng_set_tracing_group
 780  *
 781  *  Set tracing group variable with name. This function
 782  *  allocate memory pointed by tracing_group.
 783  */
 784 int lttng_set_tracing_group(const char *name)
 785 {
 786         if (asprintf(&tracing_group, "%s", name) < 0) {
 787                 return -ENOMEM;
 788         }
 789
 790         return 0;
 791 }
 792
 793 /*
 794  *  lttng_calibrate
 795  */
 796 int lttng_calibrate(struct lttng_handle *handle,
 797                 struct lttng_calibrate *calibrate)
 798 {
 799         struct lttcomm_session_msg lsm;
 800
 801         if (!handle) {
 802                 return -1;
 803         }
 804
 805         lsm.cmd_type = LTTNG_CALIBRATE;
 806         copy_lttng_domain(&lsm.domain, &handle->domain);
 807
 808         memcpy(&lsm.u.calibrate, calibrate, sizeof(lsm.u.calibrate));
 809
 810         return ask_sessiond(&lsm, NULL);
 811 }
 812
 813 /*
 814  * Check if session daemon is alive.
 815  *
 816  * Return 1 if alive or 0 if not.
 817  * On error return -1
 818  */
 819 int lttng_session_daemon_alive(void)
 820 {
 821         int ret;
 822
 823         ret = set_session_daemon_path();
 824         if (ret < 0) {
 825                 /* Error */
 826                 return ret;
 827         }
 828
 829         if (strlen(sessiond_sock_path) == 0) {
 830                 /* No socket path set. Weird error */
 831                 return -1;
 832         }
 833
 834         ret = try_connect_sessiond(sessiond_sock_path);
 835         if (ret < 0) {
 836                 /* Not alive */
 837                 return 0;
 838         }
 839
 840         /* Is alive */
 841         return 1;
 842 }
 843
 844 /*
 845  * lib constructor
 846  */
 847 static void __attribute__((constructor)) init()
 848 {
 849         /* Set default session group */
 850         lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
 851 }