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 modify it
   9  * under the terms of the GNU Lesser General Public License, version 2.1 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with this library; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #define _GNU_SOURCE
  23 #include <assert.h>
  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/common.h>
  32 #include <common/defaults.h>
  33 #include <common/sessiond-comm/sessiond-comm.h>
  34 #include <common/uri.h>
  35 #include <common/utils.h>
  36 #include <lttng/lttng.h>
  37
  38 #include "filter/filter-ast.h"
  39 #include "filter/filter-parser.h"
  40 #include "filter/filter-bytecode.h"
  41 #include "filter/memstream.h"
  42 #include "lttng-ctl-helper.h"
  43
  44 #ifdef DEBUG
  45 static const int print_xml = 1;
  46 #define dbg_printf(fmt, args...)        \
  47         printf("[debug liblttng-ctl] " fmt, ## args)
  48 #else
  49 static const int print_xml = 0;
  50 #define dbg_printf(fmt, args...)                                \
  51 do {                                                            \
  52         /* do nothing but check printf format */                \
  53         if (0)                                                  \
  54                 printf("[debug liblttnctl] " fmt, ## args);     \
  55 } while (0)
  56 #endif
  57
  58
  59 /* Socket to session daemon for communication */
  60 static int sessiond_socket;
  61 static char sessiond_sock_path[PATH_MAX];
  62 static char health_sock_path[PATH_MAX];
  63
  64 /* Variables */
  65 static char *tracing_group;
  66 static int connected;
  67
  68 /* Global */
  69
  70 /*
  71  * Those two variables are used by error.h to silent or control the verbosity of
  72  * error message. They are global to the library so application linking with it
  73  * are able to compile correctly and also control verbosity of the library.
  74  */
  75 int lttng_opt_quiet;
  76 int lttng_opt_verbose;
  77
  78 /*
  79  * Copy string from src to dst and enforce null terminated byte.
  80  */
  81 LTTNG_HIDDEN
  82 void lttng_ctl_copy_string(char *dst, const char *src, size_t len)
  83 {
  84         if (src && dst) {
  85                 strncpy(dst, src, len);
  86                 /* Enforce the NULL terminated byte */
  87                 dst[len - 1] = '\0';
  88         } else if (dst) {
  89                 dst[0] = '\0';
  90         }
  91 }
  92
  93 /*
  94  * Copy domain to lttcomm_session_msg domain.
  95  *
  96  * If domain is unknown, default domain will be the kernel.
  97  */
  98 LTTNG_HIDDEN
  99 void lttng_ctl_copy_lttng_domain(struct lttng_domain *dst,
 100                 struct lttng_domain *src)
 101 {
 102         if (src && dst) {
 103                 switch (src->type) {
 104                 case LTTNG_DOMAIN_KERNEL:
 105                 case LTTNG_DOMAIN_UST:
 106                         memcpy(dst, src, sizeof(struct lttng_domain));
 107                         break;
 108                 default:
 109                         memset(dst, 0, sizeof(struct lttng_domain));
 110                         break;
 111                 }
 112         }
 113 }
 114
 115 /*
 116  * Send lttcomm_session_msg to the session daemon.
 117  *
 118  * On success, returns the number of bytes sent (>=0)
 119  * On error, returns -1
 120  */
 121 static int send_session_msg(struct lttcomm_session_msg *lsm)
 122 {
 123         int ret;
 124
 125         if (!connected) {
 126                 ret = -LTTNG_ERR_NO_SESSIOND;
 127                 goto end;
 128         }
 129
 130         DBG("LSM cmd type : %d", lsm->cmd_type);
 131
 132         ret = lttcomm_send_creds_unix_sock(sessiond_socket, lsm,
 133                         sizeof(struct lttcomm_session_msg));
 134         if (ret < 0) {
 135                 ret = -LTTNG_ERR_FATAL;
 136         }
 137
 138 end:
 139         return ret;
 140 }
 141
 142 /*
 143  * Send var len data to the session daemon.
 144  *
 145  * On success, returns the number of bytes sent (>=0)
 146  * On error, returns -1
 147  */
 148 static int send_session_varlen(void *data, size_t len)
 149 {
 150         int ret;
 151
 152         if (!connected) {
 153                 ret = -LTTNG_ERR_NO_SESSIOND;
 154                 goto end;
 155         }
 156
 157         if (!data || !len) {
 158                 ret = 0;
 159                 goto end;
 160         }
 161
 162         ret = lttcomm_send_unix_sock(sessiond_socket, data, len);
 163         if (ret < 0) {
 164                 ret = -LTTNG_ERR_FATAL;
 165         }
 166
 167 end:
 168         return ret;
 169 }
 170
 171 /*
 172  * Receive data from the sessiond socket.
 173  *
 174  * On success, returns the number of bytes received (>=0)
 175  * On error, returns -1 (recvmsg() error) or -ENOTCONN
 176  */
 177 static int recv_data_sessiond(void *buf, size_t len)
 178 {
 179         int ret;
 180
 181         if (!connected) {
 182                 ret = -LTTNG_ERR_NO_SESSIOND;
 183                 goto end;
 184         }
 185
 186         ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
 187         if (ret < 0) {
 188                 ret = -LTTNG_ERR_FATAL;
 189         }
 190
 191 end:
 192         return ret;
 193 }
 194
 195 /*
 196  *  Check if we are in the specified group.
 197  *
 198  *  If yes return 1, else return -1.
 199  */
 200 static int check_tracing_group(const char *grp_name)
 201 {
 202         struct group *grp_tracing;      /* no free(). See getgrnam(3) */
 203         gid_t *grp_list;
 204         int grp_list_size, grp_id, i;
 205         int ret = -1;
 206
 207         /* Get GID of group 'tracing' */
 208         grp_tracing = getgrnam(grp_name);
 209         if (!grp_tracing) {
 210                 /* If grp_tracing is NULL, the group does not exist. */
 211                 goto end;
 212         }
 213
 214         /* Get number of supplementary group IDs */
 215         grp_list_size = getgroups(0, NULL);
 216         if (grp_list_size < 0) {
 217                 perror("getgroups");
 218                 goto end;
 219         }
 220
 221         /* Alloc group list of the right size */
 222         grp_list = malloc(grp_list_size * sizeof(gid_t));
 223         if (!grp_list) {
 224                 perror("malloc");
 225                 goto end;
 226         }
 227         grp_id = getgroups(grp_list_size, grp_list);
 228         if (grp_id < 0) {
 229                 perror("getgroups");
 230                 goto free_list;
 231         }
 232
 233         for (i = 0; i < grp_list_size; i++) {
 234                 if (grp_list[i] == grp_tracing->gr_gid) {
 235                         ret = 1;
 236                         break;
 237                 }
 238         }
 239
 240 free_list:
 241         free(grp_list);
 242
 243 end:
 244         return ret;
 245 }
 246
 247 /*
 248  * Try connect to session daemon with sock_path.
 249  *
 250  * Return 0 on success, else -1
 251  */
 252 static int try_connect_sessiond(const char *sock_path)
 253 {
 254         int ret;
 255
 256         /* If socket exist, we check if the daemon listens for connect. */
 257         ret = access(sock_path, F_OK);
 258         if (ret < 0) {
 259                 /* Not alive */
 260                 goto error;
 261         }
 262
 263         ret = lttcomm_connect_unix_sock(sock_path);
 264         if (ret < 0) {
 265                 /* Not alive */
 266                 goto error;
 267         }
 268
 269         ret = lttcomm_close_unix_sock(ret);
 270         if (ret < 0) {
 271                 perror("lttcomm_close_unix_sock");
 272         }
 273
 274         return 0;
 275
 276 error:
 277         return -1;
 278 }
 279
 280 /*
 281  * Set sessiond socket path by putting it in the global sessiond_sock_path
 282  * variable.
 283  *
 284  * Returns 0 on success, negative value on failure (the sessiond socket path
 285  * is somehow too long or ENOMEM).
 286  */
 287 static int set_session_daemon_path(void)
 288 {
 289         int in_tgroup = 0;      /* In tracing group */
 290         uid_t uid;
 291
 292         uid = getuid();
 293
 294         if (uid != 0) {
 295                 /* Are we in the tracing group ? */
 296                 in_tgroup = check_tracing_group(tracing_group);
 297         }
 298
 299         if ((uid == 0) || in_tgroup) {
 300                 lttng_ctl_copy_string(sessiond_sock_path,
 301                                 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK, sizeof(sessiond_sock_path));
 302         }
 303
 304         if (uid != 0) {
 305                 int ret;
 306
 307                 if (in_tgroup) {
 308                         /* Tracing group */
 309                         ret = try_connect_sessiond(sessiond_sock_path);
 310                         if (ret >= 0) {
 311                                 goto end;
 312                         }
 313                         /* Global session daemon not available... */
 314                 }
 315                 /* ...or not in tracing group (and not root), default */
 316
 317                 /*
 318                  * With GNU C <  2.1, snprintf returns -1 if the target buffer is too small;
 319                  * With GNU C >= 2.1, snprintf returns the required size (excluding closing null)
 320                  */
 321                 ret = snprintf(sessiond_sock_path, sizeof(sessiond_sock_path),
 322                                 DEFAULT_HOME_CLIENT_UNIX_SOCK, utils_get_home_dir());
 323                 if ((ret < 0) || (ret >= sizeof(sessiond_sock_path))) {
 324                         goto error;
 325                 }
 326         }
 327 end:
 328         return 0;
 329
 330 error:
 331         return -1;
 332 }
 333
 334 /*
 335  *  Connect to the LTTng session daemon.
 336  *
 337  *  On success, return 0. On error, return -1.
 338  */
 339 static int connect_sessiond(void)
 340 {
 341         int ret;
 342
 343         ret = set_session_daemon_path();
 344         if (ret < 0) {
 345                 goto error;
 346         }
 347
 348         /* Connect to the sesssion daemon */
 349         ret = lttcomm_connect_unix_sock(sessiond_sock_path);
 350         if (ret < 0) {
 351                 goto error;
 352         }
 353
 354         sessiond_socket = ret;
 355         connected = 1;
 356
 357         return 0;
 358
 359 error:
 360         return -1;
 361 }
 362
 363 /*
 364  *  Clean disconnect from the session daemon.
 365  *  On success, return 0. On error, return -1.
 366  */
 367 static int disconnect_sessiond(void)
 368 {
 369         int ret = 0;
 370
 371         if (connected) {
 372                 ret = lttcomm_close_unix_sock(sessiond_socket);
 373                 sessiond_socket = 0;
 374                 connected = 0;
 375         }
 376
 377         return ret;
 378 }
 379
 380 /*
 381  * Ask the session daemon a specific command and put the data into buf.
 382  * Takes extra var. len. data as input to send to the session daemon.
 383  *
 384  * Return size of data (only payload, not header) or a negative error code.
 385  */
 386 LTTNG_HIDDEN
 387 int lttng_ctl_ask_sessiond_varlen(struct lttcomm_session_msg *lsm,
 388                 void *vardata, size_t varlen, void **buf)
 389 {
 390         int ret;
 391         size_t size;
 392         void *data = NULL;
 393         struct lttcomm_lttng_msg llm;
 394
 395         ret = connect_sessiond();
 396         if (ret < 0) {
 397                 ret = -LTTNG_ERR_NO_SESSIOND;
 398                 goto end;
 399         }
 400
 401         /* Send command to session daemon */
 402         ret = send_session_msg(lsm);
 403         if (ret < 0) {
 404                 /* Ret value is a valid lttng error code. */
 405                 goto end;
 406         }
 407         /* Send var len data */
 408         ret = send_session_varlen(vardata, varlen);
 409         if (ret < 0) {
 410                 /* Ret value is a valid lttng error code. */
 411                 goto end;
 412         }
 413
 414         /* Get header from data transmission */
 415         ret = recv_data_sessiond(&llm, sizeof(llm));
 416         if (ret < 0) {
 417                 /* Ret value is a valid lttng error code. */
 418                 goto end;
 419         }
 420
 421         /* Check error code if OK */
 422         if (llm.ret_code != LTTNG_OK) {
 423                 ret = -llm.ret_code;
 424                 goto end;
 425         }
 426
 427         size = llm.data_size;
 428         if (size == 0) {
 429                 /* If client free with size 0 */
 430                 if (buf != NULL) {
 431                         *buf = NULL;
 432                 }
 433                 ret = 0;
 434                 goto end;
 435         }
 436
 437         data = (void*) malloc(size);
 438
 439         /* Get payload data */
 440         ret = recv_data_sessiond(data, size);
 441         if (ret < 0) {
 442                 free(data);
 443                 goto end;
 444         }
 445
 446         /*
 447          * Extra protection not to dereference a NULL pointer. If buf is NULL at
 448          * this point, an error is returned and data is freed.
 449          */
 450         if (buf == NULL) {
 451                 ret = -LTTNG_ERR_INVALID;
 452                 free(data);
 453                 goto end;
 454         }
 455
 456         *buf = data;
 457         ret = size;
 458
 459 end:
 460         disconnect_sessiond();
 461         return ret;
 462 }
 463
 464 /*
 465  * Create lttng handle and return pointer.
 466  * The returned pointer will be NULL in case of malloc() error.
 467  */
 468 struct lttng_handle *lttng_create_handle(const char *session_name,
 469                 struct lttng_domain *domain)
 470 {
 471         struct lttng_handle *handle = NULL;
 472
 473         if (domain == NULL) {
 474                 goto end;
 475         }
 476
 477         handle = malloc(sizeof(struct lttng_handle));
 478         if (handle == NULL) {
 479                 PERROR("malloc handle");
 480                 goto end;
 481         }
 482
 483         /* Copy session name */
 484         lttng_ctl_copy_string(handle->session_name, session_name,
 485                         sizeof(handle->session_name));
 486
 487         /* Copy lttng domain */
 488         lttng_ctl_copy_lttng_domain(&handle->domain, domain);
 489
 490 end:
 491         return handle;
 492 }
 493
 494 /*
 495  * Destroy handle by free(3) the pointer.
 496  */
 497 void lttng_destroy_handle(struct lttng_handle *handle)
 498 {
 499         free(handle);
 500 }
 501
 502 /*
 503  * Register an outside consumer.
 504  * Returns size of returned session payload data or a negative error code.
 505  */
 506 int lttng_register_consumer(struct lttng_handle *handle,
 507                 const char *socket_path)
 508 {
 509         struct lttcomm_session_msg lsm;
 510
 511         if (handle == NULL || socket_path == NULL) {
 512                 return -LTTNG_ERR_INVALID;
 513         }
 514
 515         lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
 516         lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 517                         sizeof(lsm.session.name));
 518         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 519
 520         lttng_ctl_copy_string(lsm.u.reg.path, socket_path, sizeof(lsm.u.reg.path));
 521
 522         return lttng_ctl_ask_sessiond(&lsm, NULL);
 523 }
 524
 525 /*
 526  *  Start tracing for all traces of the session.
 527  *  Returns size of returned session payload data or a negative error code.
 528  */
 529 int lttng_start_tracing(const char *session_name)
 530 {
 531         struct lttcomm_session_msg lsm;
 532
 533         if (session_name == NULL) {
 534                 return -LTTNG_ERR_INVALID;
 535         }
 536
 537         lsm.cmd_type = LTTNG_START_TRACE;
 538
 539         lttng_ctl_copy_string(lsm.session.name, session_name,
 540                         sizeof(lsm.session.name));
 541
 542         return lttng_ctl_ask_sessiond(&lsm, NULL);
 543 }
 544
 545 /*
 546  * Stop tracing for all traces of the session.
 547  */
 548 static int _lttng_stop_tracing(const char *session_name, int wait)
 549 {
 550         int ret, data_ret;
 551         struct lttcomm_session_msg lsm;
 552
 553         if (session_name == NULL) {
 554                 return -LTTNG_ERR_INVALID;
 555         }
 556
 557         lsm.cmd_type = LTTNG_STOP_TRACE;
 558
 559         lttng_ctl_copy_string(lsm.session.name, session_name,
 560                         sizeof(lsm.session.name));
 561
 562         ret = lttng_ctl_ask_sessiond(&lsm, NULL);
 563         if (ret < 0 && ret != -LTTNG_ERR_TRACE_ALREADY_STOPPED) {
 564                 goto error;
 565         }
 566
 567         if (!wait) {
 568                 goto end;
 569         }
 570
 571         _MSG("Waiting for data availability");
 572
 573         /* Check for data availability */
 574         do {
 575                 data_ret = lttng_data_pending(session_name);
 576                 if (data_ret < 0) {
 577                         /* Return the data available call error. */
 578                         ret = data_ret;
 579                         goto error;
 580                 }
 581
 582                 /*
 583                  * Data sleep time before retrying (in usec). Don't sleep if the call
 584                  * returned value indicates availability.
 585                  */
 586                 if (data_ret) {
 587                         usleep(DEFAULT_DATA_AVAILABILITY_WAIT_TIME);
 588                         _MSG(".");
 589                 }
 590         } while (data_ret != 0);
 591
 592         MSG("");
 593
 594 end:
 595 error:
 596         return ret;
 597 }
 598
 599 /*
 600  * Stop tracing and wait for data availability.
 601  */
 602 int lttng_stop_tracing(const char *session_name)
 603 {
 604         return _lttng_stop_tracing(session_name, 1);
 605 }
 606
 607 /*
 608  * Stop tracing but _don't_ wait for data availability.
 609  */
 610 int lttng_stop_tracing_no_wait(const char *session_name)
 611 {
 612         return _lttng_stop_tracing(session_name, 0);
 613 }
 614
 615 /*
 616  * Add context to a channel.
 617  *
 618  * If the given channel is NULL, add the contexts to all channels.
 619  * The event_name param is ignored.
 620  *
 621  * Returns the size of the returned payload data or a negative error code.
 622  */
 623 int lttng_add_context(struct lttng_handle *handle,
 624                 struct lttng_event_context *ctx, const char *event_name,
 625                 const char *channel_name)
 626 {
 627         struct lttcomm_session_msg lsm;
 628
 629         /* Safety check. Both are mandatory */
 630         if (handle == NULL || ctx == NULL) {
 631                 return -LTTNG_ERR_INVALID;
 632         }
 633
 634         memset(&lsm, 0, sizeof(lsm));
 635
 636         lsm.cmd_type = LTTNG_ADD_CONTEXT;
 637
 638         /* Copy channel name */
 639         lttng_ctl_copy_string(lsm.u.context.channel_name, channel_name,
 640                         sizeof(lsm.u.context.channel_name));
 641
 642         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 643
 644         memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
 645
 646         lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 647                         sizeof(lsm.session.name));
 648
 649         return lttng_ctl_ask_sessiond(&lsm, NULL);
 650 }
 651
 652 /*
 653  *  Enable event(s) for a channel.
 654  *  If no event name is specified, all events are enabled.
 655  *  If no channel name is specified, the default 'channel0' is used.
 656  *  Returns size of returned session payload data or a negative error code.
 657  */
 658 int lttng_enable_event(struct lttng_handle *handle,
 659                 struct lttng_event *ev, const char *channel_name)
 660 {
 661         struct lttcomm_session_msg lsm;
 662
 663         if (handle == NULL || ev == NULL) {
 664                 return -LTTNG_ERR_INVALID;
 665         }
 666
 667         memset(&lsm, 0, sizeof(lsm));
 668
 669         /* If no channel name, we put the default name */
 670         if (channel_name == NULL) {
 671                 lttng_ctl_copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME,
 672                                 sizeof(lsm.u.enable.channel_name));
 673         } else {
 674                 lttng_ctl_copy_string(lsm.u.enable.channel_name, channel_name,
 675                                 sizeof(lsm.u.enable.channel_name));
 676         }
 677
 678         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 679
 680         if (ev->name[0] != '\0') {
 681                 lsm.cmd_type = LTTNG_ENABLE_EVENT;
 682         } else {
 683                 lsm.cmd_type = LTTNG_ENABLE_ALL_EVENT;
 684         }
 685         memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
 686
 687         lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 688                         sizeof(lsm.session.name));
 689
 690         return lttng_ctl_ask_sessiond(&lsm, NULL);
 691 }
 692
 693 /*
 694  * Create or enable an event with a filter expression.
 695  *
 696  * Return negative error value on error.
 697  * Return size of returned session payload data if OK.
 698  */
 699 int lttng_enable_event_with_filter(struct lttng_handle *handle,
 700                 struct lttng_event *event, const char *channel_name,
 701                 const char *filter_expression)
 702 {
 703         struct lttcomm_session_msg lsm;
 704         struct filter_parser_ctx *ctx;
 705         FILE *fmem;
 706         int ret = 0;
 707
 708         if (!filter_expression) {
 709                 /*
 710                  * Fall back to normal event enabling if no filter
 711                  * specified.
 712                  */
 713                 return lttng_enable_event(handle, event, channel_name);
 714         }
 715
 716         /*
 717          * Empty filter string will always be rejected by the parser
 718          * anyway, so treat this corner-case early to eliminate
 719          * lttng_fmemopen error for 0-byte allocation.
 720          */
 721         if (handle == NULL || filter_expression[0] == '\0') {
 722                 return -LTTNG_ERR_INVALID;
 723         }
 724
 725         /*
 726          * casting const to non-const, as the underlying function will
 727          * use it in read-only mode.
 728          */
 729         fmem = lttng_fmemopen((void *) filter_expression,
 730                         strlen(filter_expression), "r");
 731         if (!fmem) {
 732                 fprintf(stderr, "Error opening memory as stream\n");
 733                 return -LTTNG_ERR_FILTER_NOMEM;
 734         }
 735         ctx = filter_parser_ctx_alloc(fmem);
 736         if (!ctx) {
 737                 fprintf(stderr, "Error allocating parser\n");
 738                 ret = -LTTNG_ERR_FILTER_NOMEM;
 739                 goto alloc_error;
 740         }
 741         ret = filter_parser_ctx_append_ast(ctx);
 742         if (ret) {
 743                 fprintf(stderr, "Parse error\n");
 744                 ret = -LTTNG_ERR_FILTER_INVAL;
 745                 goto parse_error;
 746         }
 747         ret = filter_visitor_set_parent(ctx);
 748         if (ret) {
 749                 fprintf(stderr, "Set parent error\n");
 750                 ret = -LTTNG_ERR_FILTER_INVAL;
 751                 goto parse_error;
 752         }
 753         if (print_xml) {
 754                 ret = filter_visitor_print_xml(ctx, stdout, 0);
 755                 if (ret) {
 756                         fflush(stdout);
 757                         fprintf(stderr, "XML print error\n");
 758                         ret = -LTTNG_ERR_FILTER_INVAL;
 759                         goto parse_error;
 760                 }
 761         }
 762
 763         dbg_printf("Generating IR... ");
 764         fflush(stdout);
 765         ret = filter_visitor_ir_generate(ctx);
 766         if (ret) {
 767                 fprintf(stderr, "Generate IR error\n");
 768                 ret = -LTTNG_ERR_FILTER_INVAL;
 769                 goto parse_error;
 770         }
 771         dbg_printf("done\n");
 772
 773         dbg_printf("Validating IR... ");
 774         fflush(stdout);
 775         ret = filter_visitor_ir_check_binary_op_nesting(ctx);
 776         if (ret) {
 777                 ret = -LTTNG_ERR_FILTER_INVAL;
 778                 goto parse_error;
 779         }
 780         dbg_printf("done\n");
 781
 782         dbg_printf("Generating bytecode... ");
 783         fflush(stdout);
 784         ret = filter_visitor_bytecode_generate(ctx);
 785         if (ret) {
 786                 fprintf(stderr, "Generate bytecode error\n");
 787                 ret = -LTTNG_ERR_FILTER_INVAL;
 788                 goto parse_error;
 789         }
 790         dbg_printf("done\n");
 791         dbg_printf("Size of bytecode generated: %u bytes.\n",
 792                 bytecode_get_len(&ctx->bytecode->b));
 793
 794         memset(&lsm, 0, sizeof(lsm));
 795
 796         lsm.cmd_type = LTTNG_ENABLE_EVENT_WITH_FILTER;
 797
 798         /* Copy channel name */
 799         lttng_ctl_copy_string(lsm.u.enable.channel_name, channel_name,
 800                         sizeof(lsm.u.enable.channel_name));
 801         /* Copy event name */
 802         if (event) {
 803                 memcpy(&lsm.u.enable.event, event, sizeof(lsm.u.enable.event));
 804         }
 805
 806         lsm.u.enable.bytecode_len = sizeof(ctx->bytecode->b)
 807                         + bytecode_get_len(&ctx->bytecode->b);
 808
 809         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 810
 811         lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 812                         sizeof(lsm.session.name));
 813
 814         ret = lttng_ctl_ask_sessiond_varlen(&lsm, &ctx->bytecode->b,
 815                                 lsm.u.enable.bytecode_len, NULL);
 816
 817         filter_bytecode_free(ctx);
 818         filter_ir_free(ctx);
 819         filter_parser_ctx_free(ctx);
 820         if (fclose(fmem) != 0) {
 821                 perror("fclose");
 822         }
 823         return ret;
 824
 825 parse_error:
 826         filter_bytecode_free(ctx);
 827         filter_ir_free(ctx);
 828         filter_parser_ctx_free(ctx);
 829 alloc_error:
 830         if (fclose(fmem) != 0) {
 831                 perror("fclose");
 832         }
 833         return ret;
 834 }
 835
 836 /*
 837  *  Disable event(s) of a channel and domain.
 838  *  If no event name is specified, all events are disabled.
 839  *  If no channel name is specified, the default 'channel0' is used.
 840  *  Returns size of returned session payload data or a negative error code.
 841  */
 842 int lttng_disable_event(struct lttng_handle *handle, const char *name,
 843                 const char *channel_name)
 844 {
 845         struct lttcomm_session_msg lsm;
 846
 847         if (handle == NULL) {
 848                 return -LTTNG_ERR_INVALID;
 849         }
 850
 851         memset(&lsm, 0, sizeof(lsm));
 852
 853         if (channel_name) {
 854                 lttng_ctl_copy_string(lsm.u.disable.channel_name, channel_name,
 855                                 sizeof(lsm.u.disable.channel_name));
 856         } else {
 857                 lttng_ctl_copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME,
 858                                 sizeof(lsm.u.disable.channel_name));
 859         }
 860
 861         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 862
 863         if (name != NULL) {
 864                 lttng_ctl_copy_string(lsm.u.disable.name, name,
 865                                 sizeof(lsm.u.disable.name));
 866                 lsm.cmd_type = LTTNG_DISABLE_EVENT;
 867         } else {
 868                 lsm.cmd_type = LTTNG_DISABLE_ALL_EVENT;
 869         }
 870
 871         lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 872                         sizeof(lsm.session.name));
 873
 874         return lttng_ctl_ask_sessiond(&lsm, NULL);
 875 }
 876
 877 /*
 878  *  Enable channel per domain
 879  *  Returns size of returned session payload data or a negative error code.
 880  */
 881 int lttng_enable_channel(struct lttng_handle *handle,
 882                 struct lttng_channel *chan)
 883 {
 884         struct lttcomm_session_msg lsm;
 885
 886         /*
 887          * NULL arguments are forbidden. No default values.
 888          */
 889         if (handle == NULL || chan == NULL) {
 890                 return -LTTNG_ERR_INVALID;
 891         }
 892
 893         memset(&lsm, 0, sizeof(lsm));
 894
 895         memcpy(&lsm.u.channel.chan, chan, sizeof(lsm.u.channel.chan));
 896
 897         lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
 898
 899         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 900
 901         lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 902                         sizeof(lsm.session.name));
 903
 904         return lttng_ctl_ask_sessiond(&lsm, NULL);
 905 }
 906
 907 /*
 908  *  All tracing will be stopped for registered events of the channel.
 909  *  Returns size of returned session payload data or a negative error code.
 910  */
 911 int lttng_disable_channel(struct lttng_handle *handle, const char *name)
 912 {
 913         struct lttcomm_session_msg lsm;
 914
 915         /* Safety check. Both are mandatory */
 916         if (handle == NULL || name == NULL) {
 917                 return -LTTNG_ERR_INVALID;
 918         }
 919
 920         memset(&lsm, 0, sizeof(lsm));
 921
 922         lsm.cmd_type = LTTNG_DISABLE_CHANNEL;
 923
 924         lttng_ctl_copy_string(lsm.u.disable.channel_name, name,
 925                         sizeof(lsm.u.disable.channel_name));
 926
 927         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 928
 929         lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 930                         sizeof(lsm.session.name));
 931
 932         return lttng_ctl_ask_sessiond(&lsm, NULL);
 933 }
 934
 935 /*
 936  *  Lists all available tracepoints of domain.
 937  *  Sets the contents of the events array.
 938  *  Returns the number of lttng_event entries in events;
 939  *  on error, returns a negative value.
 940  */
 941 int lttng_list_tracepoints(struct lttng_handle *handle,
 942                 struct lttng_event **events)
 943 {
 944         int ret;
 945         struct lttcomm_session_msg lsm;
 946
 947         if (handle == NULL) {
 948                 return -LTTNG_ERR_INVALID;
 949         }
 950
 951         lsm.cmd_type = LTTNG_LIST_TRACEPOINTS;
 952         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 953
 954         ret = lttng_ctl_ask_sessiond(&lsm, (void **) events);
 955         if (ret < 0) {
 956                 return ret;
 957         }
 958
 959         return ret / sizeof(struct lttng_event);
 960 }
 961
 962 /*
 963  *  Lists all available tracepoint fields of domain.
 964  *  Sets the contents of the event field array.
 965  *  Returns the number of lttng_event_field entries in events;
 966  *  on error, returns a negative value.
 967  */
 968 int lttng_list_tracepoint_fields(struct lttng_handle *handle,
 969                 struct lttng_event_field **fields)
 970 {
 971         int ret;
 972         struct lttcomm_session_msg lsm;
 973
 974         if (handle == NULL) {
 975                 return -LTTNG_ERR_INVALID;
 976         }
 977
 978         lsm.cmd_type = LTTNG_LIST_TRACEPOINT_FIELDS;
 979         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 980
 981         ret = lttng_ctl_ask_sessiond(&lsm, (void **) fields);
 982         if (ret < 0) {
 983                 return ret;
 984         }
 985
 986         return ret / sizeof(struct lttng_event_field);
 987 }
 988
 989 /*
 990  *  Returns a human readable string describing
 991  *  the error code (a negative value).
 992  */
 993 const char *lttng_strerror(int code)
 994 {
 995         return error_get_str(code);
 996 }
 997
 998 /*
 999  * Create a brand new session using name and url for destination.
1000  *
1001  * Returns LTTNG_OK on success or a negative error code.
1002  */
1003 int lttng_create_session(const char *name, const char *url)
1004 {
1005         int ret;
1006         ssize_t size;
1007         struct lttcomm_session_msg lsm;
1008         struct lttng_uri *uris = NULL;
1009
1010         if (name == NULL) {
1011                 return -LTTNG_ERR_INVALID;
1012         }
1013
1014         memset(&lsm, 0, sizeof(lsm));
1015
1016         lsm.cmd_type = LTTNG_CREATE_SESSION;
1017         lttng_ctl_copy_string(lsm.session.name, name, sizeof(lsm.session.name));
1018
1019         /* There should never be a data URL */
1020         size = uri_parse_str_urls(url, NULL, &uris);
1021         if (size < 0) {
1022                 return -LTTNG_ERR_INVALID;
1023         }
1024
1025         lsm.u.uri.size = size;
1026
1027         ret = lttng_ctl_ask_sessiond_varlen(&lsm, uris,
1028                         sizeof(struct lttng_uri) * size, NULL);
1029
1030         free(uris);
1031         return ret;
1032 }
1033
1034 /*
1035  *  Destroy session using name.
1036  *  Returns size of returned session payload data or a negative error code.
1037  */
1038 int lttng_destroy_session(const char *session_name)
1039 {
1040         struct lttcomm_session_msg lsm;
1041
1042         if (session_name == NULL) {
1043                 return -LTTNG_ERR_INVALID;
1044         }
1045
1046         lsm.cmd_type = LTTNG_DESTROY_SESSION;
1047
1048         lttng_ctl_copy_string(lsm.session.name, session_name,
1049                         sizeof(lsm.session.name));
1050
1051         return lttng_ctl_ask_sessiond(&lsm, NULL);
1052 }
1053
1054 /*
1055  *  Ask the session daemon for all available sessions.
1056  *  Sets the contents of the sessions array.
1057  *  Returns the number of lttng_session entries in sessions;
1058  *  on error, returns a negative value.
1059  */
1060 int lttng_list_sessions(struct lttng_session **sessions)
1061 {
1062         int ret;
1063         struct lttcomm_session_msg lsm;
1064
1065         lsm.cmd_type = LTTNG_LIST_SESSIONS;
1066         ret = lttng_ctl_ask_sessiond(&lsm, (void**) sessions);
1067         if (ret < 0) {
1068                 return ret;
1069         }
1070
1071         return ret / sizeof(struct lttng_session);
1072 }
1073
1074 /*
1075  *  Ask the session daemon for all available domains of a session.
1076  *  Sets the contents of the domains array.
1077  *  Returns the number of lttng_domain entries in domains;
1078  *  on error, returns a negative value.
1079  */
1080 int lttng_list_domains(const char *session_name,
1081                 struct lttng_domain **domains)
1082 {
1083         int ret;
1084         struct lttcomm_session_msg lsm;
1085
1086         if (session_name == NULL) {
1087                 return -LTTNG_ERR_INVALID;
1088         }
1089
1090         lsm.cmd_type = LTTNG_LIST_DOMAINS;
1091
1092         lttng_ctl_copy_string(lsm.session.name, session_name,
1093                         sizeof(lsm.session.name));
1094
1095         ret = lttng_ctl_ask_sessiond(&lsm, (void**) domains);
1096         if (ret < 0) {
1097                 return ret;
1098         }
1099
1100         return ret / sizeof(struct lttng_domain);
1101 }
1102
1103 /*
1104  *  Ask the session daemon for all available channels of a session.
1105  *  Sets the contents of the channels array.
1106  *  Returns the number of lttng_channel entries in channels;
1107  *  on error, returns a negative value.
1108  */
1109 int lttng_list_channels(struct lttng_handle *handle,
1110                 struct lttng_channel **channels)
1111 {
1112         int ret;
1113         struct lttcomm_session_msg lsm;
1114
1115         if (handle == NULL) {
1116                 return -LTTNG_ERR_INVALID;
1117         }
1118
1119         lsm.cmd_type = LTTNG_LIST_CHANNELS;
1120         lttng_ctl_copy_string(lsm.session.name, handle->session_name,
1121                         sizeof(lsm.session.name));
1122
1123         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
1124
1125         ret = lttng_ctl_ask_sessiond(&lsm, (void**) channels);
1126         if (ret < 0) {
1127                 return ret;
1128         }
1129
1130         return ret / sizeof(struct lttng_channel);
1131 }
1132
1133 /*
1134  *  Ask the session daemon for all available events of a session channel.
1135  *  Sets the contents of the events array.
1136  *  Returns the number of lttng_event entries in events;
1137  *  on error, returns a negative value.
1138  */
1139 int lttng_list_events(struct lttng_handle *handle,
1140                 const char *channel_name, struct lttng_event **events)
1141 {
1142         int ret;
1143         struct lttcomm_session_msg lsm;
1144
1145         /* Safety check. An handle and channel name are mandatory */
1146         if (handle == NULL || channel_name == NULL) {
1147                 return -LTTNG_ERR_INVALID;
1148         }
1149
1150         lsm.cmd_type = LTTNG_LIST_EVENTS;
1151         lttng_ctl_copy_string(lsm.session.name, handle->session_name,
1152                         sizeof(lsm.session.name));
1153         lttng_ctl_copy_string(lsm.u.list.channel_name, channel_name,
1154                         sizeof(lsm.u.list.channel_name));
1155
1156         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
1157
1158         ret = lttng_ctl_ask_sessiond(&lsm, (void**) events);
1159         if (ret < 0) {
1160                 return ret;
1161         }
1162
1163         return ret / sizeof(struct lttng_event);
1164 }
1165
1166 /*
1167  * Sets the tracing_group variable with name.
1168  * This function allocates memory pointed to by tracing_group.
1169  * On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
1170  */
1171 int lttng_set_tracing_group(const char *name)
1172 {
1173         if (name == NULL) {
1174                 return -LTTNG_ERR_INVALID;
1175         }
1176
1177         if (asprintf(&tracing_group, "%s", name) < 0) {
1178                 return -LTTNG_ERR_FATAL;
1179         }
1180
1181         return 0;
1182 }
1183
1184 /*
1185  * Returns size of returned session payload data or a negative error code.
1186  */
1187 int lttng_calibrate(struct lttng_handle *handle,
1188                 struct lttng_calibrate *calibrate)
1189 {
1190         struct lttcomm_session_msg lsm;
1191
1192         /* Safety check. NULL pointer are forbidden */
1193         if (handle == NULL || calibrate == NULL) {
1194                 return -LTTNG_ERR_INVALID;
1195         }
1196
1197         lsm.cmd_type = LTTNG_CALIBRATE;
1198         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
1199
1200         memcpy(&lsm.u.calibrate, calibrate, sizeof(lsm.u.calibrate));
1201
1202         return lttng_ctl_ask_sessiond(&lsm, NULL);
1203 }
1204
1205 /*
1206  * Set default channel attributes.
1207  * If either or both of the arguments are null, attr content is zeroe'd.
1208  */
1209 void lttng_channel_set_default_attr(struct lttng_domain *domain,
1210                 struct lttng_channel_attr *attr)
1211 {
1212         /* Safety check */
1213         if (attr == NULL || domain == NULL) {
1214                 return;
1215         }
1216
1217         memset(attr, 0, sizeof(struct lttng_channel_attr));
1218
1219         /* Same for all domains. */
1220         attr->overwrite = DEFAULT_CHANNEL_OVERWRITE;
1221         attr->tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
1222         attr->tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
1223
1224         switch (domain->type) {
1225         case LTTNG_DOMAIN_KERNEL:
1226                 attr->switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
1227                 attr->read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
1228                 attr->subbuf_size = default_get_kernel_channel_subbuf_size();
1229                 attr->num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
1230                 attr->output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
1231                 break;
1232         case LTTNG_DOMAIN_UST:
1233                 switch (domain->buf_type) {
1234                 case LTTNG_BUFFER_PER_UID:
1235                         attr->subbuf_size = default_get_ust_uid_channel_subbuf_size();
1236                         attr->num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
1237                         attr->output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
1238                         attr->switch_timer_interval = DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
1239                         attr->read_timer_interval = DEFAULT_UST_UID_CHANNEL_READ_TIMER;
1240                         break;
1241                 case LTTNG_BUFFER_PER_PID:
1242                 default:
1243                         attr->subbuf_size = default_get_ust_pid_channel_subbuf_size();
1244                         attr->num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
1245                         attr->output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
1246                         attr->switch_timer_interval = DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
1247                         attr->read_timer_interval = DEFAULT_UST_PID_CHANNEL_READ_TIMER;
1248                         break;
1249                 }
1250         default:
1251                 /* Default behavior: leave set to 0. */
1252                 break;
1253         }
1254 }
1255
1256 /*
1257  * Check if session daemon is alive.
1258  *
1259  * Return 1 if alive or 0 if not.
1260  * On error returns a negative value.
1261  */
1262 int lttng_session_daemon_alive(void)
1263 {
1264         int ret;
1265
1266         ret = set_session_daemon_path();
1267         if (ret < 0) {
1268                 /* Error */
1269                 return ret;
1270         }
1271
1272         if (*sessiond_sock_path == '\0') {
1273                 /*
1274                  * No socket path set. Weird error which means the constructor was not
1275                  * called.
1276                  */
1277                 assert(0);
1278         }
1279
1280         ret = try_connect_sessiond(sessiond_sock_path);
1281         if (ret < 0) {
1282                 /* Not alive */
1283                 return 0;
1284         }
1285
1286         /* Is alive */
1287         return 1;
1288 }
1289
1290 /*
1291  * Set URL for a consumer for a session and domain.
1292  *
1293  * Return 0 on success, else a negative value.
1294  */
1295 int lttng_set_consumer_url(struct lttng_handle *handle,
1296                 const char *control_url, const char *data_url)
1297 {
1298         int ret;
1299         ssize_t size;
1300         struct lttcomm_session_msg lsm;
1301         struct lttng_uri *uris = NULL;
1302
1303         if (handle == NULL || (control_url == NULL && data_url == NULL)) {
1304                 return -LTTNG_ERR_INVALID;
1305         }
1306
1307         memset(&lsm, 0, sizeof(lsm));
1308
1309         lsm.cmd_type = LTTNG_SET_CONSUMER_URI;
1310
1311         lttng_ctl_copy_string(lsm.session.name, handle->session_name,
1312                         sizeof(lsm.session.name));
1313         lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
1314
1315         size = uri_parse_str_urls(control_url, data_url, &uris);
1316         if (size < 0) {
1317                 return -LTTNG_ERR_INVALID;
1318         }
1319
1320         lsm.u.uri.size = size;
1321
1322         ret = lttng_ctl_ask_sessiond_varlen(&lsm, uris,
1323                         sizeof(struct lttng_uri) * size, NULL);
1324
1325         free(uris);
1326         return ret;
1327 }
1328
1329 /*
1330  * [OBSOLETE]
1331  */
1332 int lttng_enable_consumer(struct lttng_handle *handle)
1333 {
1334         return -ENOSYS;
1335 }
1336
1337 /*
1338  * [OBSOLETE]
1339  */
1340 int lttng_disable_consumer(struct lttng_handle *handle)
1341 {
1342         return -ENOSYS;
1343 }
1344
1345 /*
1346  * Set health socket path by putting it in the global health_sock_path
1347  * variable.
1348  *
1349  * Returns 0 on success or assert(0) on ENOMEM.
1350  */
1351 static int set_health_socket_path(void)
1352 {
1353         int in_tgroup = 0;      /* In tracing group */
1354         uid_t uid;
1355         const char *home;
1356
1357         uid = getuid();
1358
1359         if (uid != 0) {
1360                 /* Are we in the tracing group ? */
1361                 in_tgroup = check_tracing_group(tracing_group);
1362         }
1363
1364         if ((uid == 0) || in_tgroup) {
1365                 lttng_ctl_copy_string(health_sock_path,
1366                                 DEFAULT_GLOBAL_HEALTH_UNIX_SOCK, sizeof(health_sock_path));
1367         }
1368
1369         if (uid != 0) {
1370                 int ret;
1371
1372                 /*
1373                  * With GNU C <  2.1, snprintf returns -1 if the target buffer is too small;
1374                  * With GNU C >= 2.1, snprintf returns the required size (excluding closing null)
1375                  */
1376                 home = utils_get_home_dir();
1377                 if (home == NULL) {
1378                         /* Fallback in /tmp .. */
1379                         home = "/tmp";
1380                 }
1381
1382                 ret = snprintf(health_sock_path, sizeof(health_sock_path),
1383                                 DEFAULT_HOME_HEALTH_UNIX_SOCK, home);
1384                 if ((ret < 0) || (ret >= sizeof(health_sock_path))) {
1385                         /* ENOMEM at this point... just kill the control lib. */
1386                         assert(0);
1387                 }
1388         }
1389
1390         return 0;
1391 }
1392
1393 /*
1394  * Check session daemon health for a specific health component.
1395  *
1396  * Return 0 if health is OK or else 1 if BAD.
1397  *
1398  * Any other negative value is a lttng error code which can be translated with
1399  * lttng_strerror().
1400  */
1401 int lttng_health_check(enum lttng_health_component c)
1402 {
1403         int sock, ret;
1404         struct lttcomm_health_msg msg;
1405         struct lttcomm_health_data reply;
1406
1407         /* Connect to the sesssion daemon */
1408         sock = lttcomm_connect_unix_sock(health_sock_path);
1409         if (sock < 0) {
1410                 ret = -LTTNG_ERR_NO_SESSIOND;
1411                 goto error;
1412         }
1413
1414         msg.cmd = LTTNG_HEALTH_CHECK;
1415         msg.component = c;
1416
1417         ret = lttcomm_send_unix_sock(sock, (void *)&msg, sizeof(msg));
1418         if (ret < 0) {
1419                 ret = -LTTNG_ERR_FATAL;
1420                 goto close_error;
1421         }
1422
1423         ret = lttcomm_recv_unix_sock(sock, (void *)&reply, sizeof(reply));
1424         if (ret < 0) {
1425                 ret = -LTTNG_ERR_FATAL;
1426                 goto close_error;
1427         }
1428
1429         ret = reply.ret_code;
1430
1431 close_error:
1432         {
1433                 int closeret;
1434
1435                 closeret = close(sock);
1436                 assert(!closeret);
1437         }
1438
1439 error:
1440         return ret;
1441 }
1442
1443 /*
1444  * This is an extension of create session that is ONLY and SHOULD only be used
1445  * by the lttng command line program. It exists to avoid using URI parsing in
1446  * the lttng client.
1447  *
1448  * We need the date and time for the trace path subdirectory for the case where
1449  * the user does NOT define one using either -o or -U. Using the normal
1450  * lttng_create_session API call, we have no clue on the session daemon side if
1451  * the URL was generated automatically by the client or define by the user.
1452  *
1453  * So this function "wrapper" is hidden from the public API, takes the datetime
1454  * string and appends it if necessary to the URI subdirectory before sending it
1455  * to the session daemon.
1456  *
1457  * With this extra function, the lttng_create_session call behavior is not
1458  * changed and the timestamp is appended to the URI on the session daemon side
1459  * if necessary.
1460  */
1461 int _lttng_create_session_ext(const char *name, const char *url,
1462                 const char *datetime)
1463 {
1464         int ret;
1465         ssize_t size;
1466         struct lttcomm_session_msg lsm;
1467         struct lttng_uri *uris = NULL;
1468
1469         if (name == NULL || datetime == NULL || url == NULL) {
1470                 return -LTTNG_ERR_INVALID;
1471         }
1472
1473         memset(&lsm, 0, sizeof(lsm));
1474
1475         lsm.cmd_type = LTTNG_CREATE_SESSION;
1476         lttng_ctl_copy_string(lsm.session.name, name, sizeof(lsm.session.name));
1477
1478         /* There should never be a data URL */
1479         size = uri_parse_str_urls(url, NULL, &uris);
1480         if (size < 0) {
1481                 ret = -LTTNG_ERR_INVALID;
1482                 goto error;
1483         }
1484
1485         lsm.u.uri.size = size;
1486
1487         if (size > 0 && uris[0].dtype != LTTNG_DST_PATH && strlen(uris[0].subdir) == 0) {
1488                 /* Don't append datetime if the name was automatically created. */
1489                 if (strncmp(name, DEFAULT_SESSION_NAME "-",
1490                                         strlen(DEFAULT_SESSION_NAME) + 1)) {
1491                         ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s-%s",
1492                                         name, datetime);
1493                 } else {
1494                         ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s", name);
1495                 }
1496                 if (ret < 0) {
1497                         PERROR("snprintf uri subdir");
1498                         ret = -LTTNG_ERR_FATAL;
1499                         goto error;
1500                 }
1501         }
1502
1503         ret = lttng_ctl_ask_sessiond_varlen(&lsm, uris,
1504                         sizeof(struct lttng_uri) * size, NULL);
1505
1506 error:
1507         free(uris);
1508         return ret;
1509 }
1510
1511 /*
1512  * For a given session name, this call checks if the data is ready to be read
1513  * or is still being extracted by the consumer(s) hence not ready to be used by
1514  * any readers.
1515  */
1516 int lttng_data_pending(const char *session_name)
1517 {
1518         int ret;
1519         struct lttcomm_session_msg lsm;
1520
1521         if (session_name == NULL) {
1522                 return -LTTNG_ERR_INVALID;
1523         }
1524
1525         lsm.cmd_type = LTTNG_DATA_PENDING;
1526
1527         lttng_ctl_copy_string(lsm.session.name, session_name,
1528                         sizeof(lsm.session.name));
1529
1530         ret = lttng_ctl_ask_sessiond(&lsm, NULL);
1531
1532         /*
1533          * The lttng_ctl_ask_sessiond function negate the return code if it's not
1534          * LTTNG_OK so getting -1 means that the reply ret_code was 1 thus meaning
1535          * that the data is available. Yes it is hackish but for now this is the
1536          * only way.
1537          */
1538         if (ret == -1) {
1539                 ret = 1;
1540         }
1541
1542         return ret;
1543 }
1544
1545 /*
1546  * lib constructor
1547  */
1548 static void __attribute__((constructor)) init()
1549 {
1550         /* Set default session group */
1551         lttng_set_tracing_group(DEFAULT_TRACING_GROUP);
1552         /* Set socket for health check */
1553         (void) set_health_socket_path();
1554 }
1555
1556 /*
1557  * lib destructor
1558  */
1559 static void __attribute__((destructor)) lttng_ctl_exit()
1560 {
1561         free(tracing_group);
1562 }