include/lttng/lttng.h

   1 /*
   2  * lttng.h
   3  *
   4  * Linux Trace Toolkit Control Library Header File
   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, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  15  * 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 #ifndef LTTNG_H
  23 #define LTTNG_H
  24
  25 #include <limits.h>
  26 #include <stdint.h>
  27 #include <sys/types.h>
  28
  29 /* Error codes that can be returned by API calls */
  30 #include <lttng/lttng-error.h>
  31
  32 #ifdef __cplusplus
  33 extern "C" {
  34 #endif
  35
  36 /*
  37  * Event symbol length. Copied from LTTng kernel ABI.
  38  */
  39 #define LTTNG_SYMBOL_NAME_LEN             256
  40
  41 /*
  42  * Every lttng_event_* structure both apply to kernel event and user-space
  43  * event.
  44  */
  45
  46 /*
  47  * Domain types: the different possible tracers.
  48  */
  49 enum lttng_domain_type {
  50         LTTNG_DOMAIN_KERNEL                   = 1,      /* Linux Kernel tracer. */
  51         LTTNG_DOMAIN_UST                      = 2,      /* Global Userspace tracer. */
  52         LTTNG_DOMAIN_JUL                      = 3,      /* Java Util Logging. */
  53 };
  54
  55 /*
  56  * Instrumentation type of tracing event.
  57  */
  58 enum lttng_event_type {
  59         LTTNG_EVENT_ALL                       = -1,
  60         LTTNG_EVENT_TRACEPOINT                = 0,
  61         LTTNG_EVENT_PROBE                     = 1,
  62         LTTNG_EVENT_FUNCTION                  = 2,
  63         LTTNG_EVENT_FUNCTION_ENTRY            = 3,
  64         LTTNG_EVENT_NOOP                      = 4,
  65         LTTNG_EVENT_SYSCALL                   = 5,
  66 };
  67
  68 /*
  69  * Loglevel information.
  70  */
  71 enum lttng_loglevel_type {
  72         LTTNG_EVENT_LOGLEVEL_ALL              = 0,
  73         LTTNG_EVENT_LOGLEVEL_RANGE            = 1,
  74         LTTNG_EVENT_LOGLEVEL_SINGLE           = 2,
  75 };
  76
  77 /*
  78  * Available loglevels.
  79  */
  80 enum lttng_loglevel {
  81         LTTNG_LOGLEVEL_EMERG                  = 0,
  82         LTTNG_LOGLEVEL_ALERT                  = 1,
  83         LTTNG_LOGLEVEL_CRIT                   = 2,
  84         LTTNG_LOGLEVEL_ERR                    = 3,
  85         LTTNG_LOGLEVEL_WARNING                = 4,
  86         LTTNG_LOGLEVEL_NOTICE                 = 5,
  87         LTTNG_LOGLEVEL_INFO                   = 6,
  88         LTTNG_LOGLEVEL_DEBUG_SYSTEM           = 7,
  89         LTTNG_LOGLEVEL_DEBUG_PROGRAM          = 8,
  90         LTTNG_LOGLEVEL_DEBUG_PROCESS          = 9,
  91         LTTNG_LOGLEVEL_DEBUG_MODULE           = 10,
  92         LTTNG_LOGLEVEL_DEBUG_UNIT             = 11,
  93         LTTNG_LOGLEVEL_DEBUG_FUNCTION         = 12,
  94         LTTNG_LOGLEVEL_DEBUG_LINE             = 13,
  95         LTTNG_LOGLEVEL_DEBUG                  = 14,
  96 };
  97
  98 /*
  99  * Available loglevels for the JUL domain. Those are an exact map from the
 100  * class java.util.logging.Level.
 101  */
 102 enum lttng_loglevel_jul {
 103         LTTNG_LOGLEVEL_JUL_OFF                = INT32_MAX,
 104         LTTNG_LOGLEVEL_JUL_SEVERE             = 1000,
 105         LTTNG_LOGLEVEL_JUL_WARNING            = 900,
 106         LTTNG_LOGLEVEL_JUL_INFO               = 800,
 107         LTTNG_LOGLEVEL_JUL_CONFIG             = 700,
 108         LTTNG_LOGLEVEL_JUL_FINE               = 500,
 109         LTTNG_LOGLEVEL_JUL_FINER              = 400,
 110         LTTNG_LOGLEVEL_JUL_FINEST             = 300,
 111         LTTNG_LOGLEVEL_JUL_ALL                = INT32_MIN,
 112 };
 113
 114 /*
 115  * LTTng consumer mode
 116  */
 117 enum lttng_event_output {
 118         LTTNG_EVENT_SPLICE                    = 0,
 119         LTTNG_EVENT_MMAP                      = 1,
 120 };
 121
 122 /* Event context possible type */
 123 enum lttng_event_context_type {
 124         LTTNG_EVENT_CONTEXT_PID               = 0,
 125         LTTNG_EVENT_CONTEXT_PERF_COUNTER      = 1,
 126         LTTNG_EVENT_CONTEXT_PROCNAME          = 2,
 127         LTTNG_EVENT_CONTEXT_PRIO              = 3,
 128         LTTNG_EVENT_CONTEXT_NICE              = 4,
 129         LTTNG_EVENT_CONTEXT_VPID              = 5,
 130         LTTNG_EVENT_CONTEXT_TID               = 6,
 131         LTTNG_EVENT_CONTEXT_VTID              = 7,
 132         LTTNG_EVENT_CONTEXT_PPID              = 8,
 133         LTTNG_EVENT_CONTEXT_VPPID             = 9,
 134         LTTNG_EVENT_CONTEXT_PTHREAD_ID        = 10,
 135         LTTNG_EVENT_CONTEXT_HOSTNAME          = 11,
 136         LTTNG_EVENT_CONTEXT_IP                = 12,
 137 };
 138
 139 enum lttng_calibrate_type {
 140         LTTNG_CALIBRATE_FUNCTION              = 0,
 141 };
 142
 143 /* Health component for the health check function. */
 144 enum lttng_health_component {
 145         LTTNG_HEALTH_CMD,
 146         LTTNG_HEALTH_APP_MANAGE,
 147         LTTNG_HEALTH_APP_REG,
 148         LTTNG_HEALTH_KERNEL,
 149         LTTNG_HEALTH_CONSUMER,
 150         LTTNG_HEALTH_HT_CLEANUP,
 151         LTTNG_HEALTH_APP_MANAGE_NOTIFY,
 152         LTTNG_HEALTH_APP_REG_DISPATCH,
 153         LTTNG_HEALTH_ALL,
 154 };
 155
 156 /* Buffer type for a specific domain. */
 157 enum lttng_buffer_type {
 158         LTTNG_BUFFER_PER_PID,   /* Only supported by UST being the default. */
 159         LTTNG_BUFFER_PER_UID,   /* Only supported by UST. */
 160         LTTNG_BUFFER_GLOBAL,    /* Only supported by the Kernel. */
 161 };
 162
 163 /*
 164  * The structures should be initialized to zero before use.
 165  */
 166 #define LTTNG_DOMAIN_PADDING1              12
 167 #define LTTNG_DOMAIN_PADDING2              LTTNG_SYMBOL_NAME_LEN + 32
 168 struct lttng_domain {
 169         enum lttng_domain_type type;
 170         enum lttng_buffer_type buf_type;
 171         char padding[LTTNG_DOMAIN_PADDING1];
 172
 173         union {
 174                 pid_t pid;
 175                 char exec_name[NAME_MAX];
 176                 char padding[LTTNG_DOMAIN_PADDING2];
 177         } attr;
 178 };
 179
 180 /*
 181  * Perf counter attributes
 182  *
 183  * The structures should be initialized to zero before use.
 184  */
 185 #define LTTNG_PERF_EVENT_PADDING1          16
 186 struct lttng_event_perf_counter_ctx {
 187         uint32_t type;
 188         uint64_t config;
 189         char name[LTTNG_SYMBOL_NAME_LEN];
 190
 191         char padding[LTTNG_PERF_EVENT_PADDING1];
 192 };
 193
 194 /*
 195  * Event/channel context
 196  *
 197  * The structures should be initialized to zero before use.
 198  */
 199 #define LTTNG_EVENT_CONTEXT_PADDING1       16
 200 #define LTTNG_EVENT_CONTEXT_PADDING2       LTTNG_SYMBOL_NAME_LEN + 32
 201 struct lttng_event_context {
 202         enum lttng_event_context_type ctx;
 203         char padding[LTTNG_EVENT_CONTEXT_PADDING1];
 204
 205         union {
 206                 struct lttng_event_perf_counter_ctx perf_counter;
 207                 char padding[LTTNG_EVENT_CONTEXT_PADDING2];
 208         } u;
 209 };
 210
 211 /*
 212  * Event probe.
 213  *
 214  * Either addr is used or symbol_name and offset.
 215  *
 216  * The structures should be initialized to zero before use.
 217  */
 218 #define LTTNG_EVENT_PROBE_PADDING1         16
 219 struct lttng_event_probe_attr {
 220         uint64_t addr;
 221
 222         uint64_t offset;
 223         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 224
 225         char padding[LTTNG_EVENT_PROBE_PADDING1];
 226 };
 227
 228 /*
 229  * Function tracer
 230  *
 231  * The structures should be initialized to zero before use.
 232  */
 233 #define LTTNG_EVENT_FUNCTION_PADDING1      16
 234 struct lttng_event_function_attr {
 235         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 236
 237         char padding[LTTNG_EVENT_FUNCTION_PADDING1];
 238 };
 239
 240 /*
 241  * Generic lttng event
 242  *
 243  * The structures should be initialized to zero before use.
 244  */
 245 #define LTTNG_EVENT_PADDING1               14
 246 #define LTTNG_EVENT_PADDING2               LTTNG_SYMBOL_NAME_LEN + 32
 247 struct lttng_event {
 248         enum lttng_event_type type;
 249         char name[LTTNG_SYMBOL_NAME_LEN];
 250
 251         enum lttng_loglevel_type loglevel_type;
 252         int loglevel;
 253
 254         int32_t enabled;        /* Does not apply: -1 */
 255         pid_t pid;
 256         unsigned char filter;   /* filter enabled ? */
 257         unsigned char exclusion; /* exclusions added ? */
 258
 259         char padding[LTTNG_EVENT_PADDING1];
 260
 261         /* Per event type configuration */
 262         union {
 263                 struct lttng_event_probe_attr probe;
 264                 struct lttng_event_function_attr ftrace;
 265
 266                 char padding[LTTNG_EVENT_PADDING2];
 267         } attr;
 268 };
 269
 270 enum lttng_event_field_type {
 271         LTTNG_EVENT_FIELD_OTHER                 = 0,
 272         LTTNG_EVENT_FIELD_INTEGER               = 1,
 273         LTTNG_EVENT_FIELD_ENUM                  = 2,
 274         LTTNG_EVENT_FIELD_FLOAT                 = 3,
 275         LTTNG_EVENT_FIELD_STRING                = 4,
 276 };
 277
 278 #define LTTNG_EVENT_FIELD_PADDING       LTTNG_SYMBOL_NAME_LEN + 32
 279 struct lttng_event_field {
 280         char field_name[LTTNG_SYMBOL_NAME_LEN];
 281         enum lttng_event_field_type type;
 282         char padding[LTTNG_EVENT_FIELD_PADDING];
 283         struct lttng_event event;
 284         int nowrite;
 285 };
 286
 287 /*
 288  * Tracer channel attributes. For both kernel and user-space.
 289  *
 290  * The structures should be initialized to zero before use.
 291  */
 292 #define LTTNG_CHANNEL_ATTR_PADDING1        LTTNG_SYMBOL_NAME_LEN + 12
 293 struct lttng_channel_attr {
 294         int overwrite;                      /* 1: overwrite, 0: discard */
 295         uint64_t subbuf_size;               /* bytes */
 296         uint64_t num_subbuf;                /* power of 2 */
 297         unsigned int switch_timer_interval; /* usec */
 298         unsigned int read_timer_interval;   /* usec */
 299         enum lttng_event_output output;     /* splice, mmap */
 300         /* LTTng 2.1 padding limit */
 301         uint64_t tracefile_size;            /* bytes */
 302         uint64_t tracefile_count;           /* number of tracefiles */
 303         /* LTTng 2.3 padding limit */
 304         unsigned int live_timer_interval;   /* usec */
 305
 306         char padding[LTTNG_CHANNEL_ATTR_PADDING1];
 307 };
 308
 309 /*
 310  * Channel information structure. For both kernel and user-space.
 311  *
 312  * The structures should be initialized to zero before use.
 313  */
 314 #define LTTNG_CHANNEL_PADDING1             16
 315 struct lttng_channel {
 316         char name[LTTNG_SYMBOL_NAME_LEN];
 317         uint32_t enabled;
 318         struct lttng_channel_attr attr;
 319
 320         char padding[LTTNG_CHANNEL_PADDING1];
 321 };
 322
 323 #define LTTNG_CALIBRATE_PADDING1           16
 324 struct lttng_calibrate {
 325         enum lttng_calibrate_type type;
 326
 327         char padding[LTTNG_CALIBRATE_PADDING1];
 328 };
 329
 330 /*
 331  * Basic session information.
 332  *
 333  * This is an 'output data' meaning that it only comes *from* the session
 334  * daemon *to* the lttng client. It's basically a 'human' representation of
 335  * tracing entities (here a session).
 336  *
 337  * The structures should be initialized to zero before use.
 338  */
 339 #define LTTNG_SESSION_PADDING1             12
 340 struct lttng_session {
 341         char name[NAME_MAX];
 342         /* The path where traces are written */
 343         char path[PATH_MAX];
 344         uint32_t enabled;       /* enabled/started: 1, disabled/stopped: 0 */
 345         uint32_t snapshot_mode;
 346         unsigned int live_timer_interval;       /* usec */
 347
 348         char padding[LTTNG_SESSION_PADDING1];
 349 };
 350
 351 /*
 352  * Handle used as a context for commands.
 353  *
 354  * The structures should be initialized to zero before use.
 355  */
 356 #define LTTNG_HANDLE_PADDING1              16
 357 struct lttng_handle {
 358         char session_name[NAME_MAX];
 359         struct lttng_domain domain;
 360
 361         char padding[LTTNG_HANDLE_PADDING1];
 362 };
 363
 364 /*
 365  * Public LTTng control API
 366  *
 367  * For functions having an lttng domain type as parameter, if a bad value is
 368  * given, NO default is applied and an error is returned.
 369  *
 370  * On success, all functions of the API return 0 or the size of the allocated
 371  * array (in bytes).
 372  *
 373  * On error, a negative value is returned being a specific lttng-tools error
 374  * code which can be humanly interpreted with lttng_strerror(err).
 375  *
 376  * Exceptions to this are noted below.
 377  */
 378
 379 /*
 380  * Create a handle used as a context for every request made to the library.
 381  *
 382  * This handle contains the session name and lttng domain on which the command
 383  * will be executed.
 384  * The returned pointer will be NULL in case of malloc() error.
 385  */
 386 extern struct lttng_handle *lttng_create_handle(const char *session_name,
 387                 struct lttng_domain *domain);
 388
 389 /*
 390  * Destroy an handle.
 391  *
 392  * It free(3) the data pointer returned by lttng_create_handle(), rendering it
 393  * unusable.
 394  */
 395 extern void lttng_destroy_handle(struct lttng_handle *handle);
 396
 397 /*
 398  * Create a tracing session using a name and an optional URL.
 399  *
 400  * If _url_ is NULL, no consumer is created for the session. The name can't be
 401  * NULL here.
 402  */
 403 extern int lttng_create_session(const char *name, const char *url);
 404
 405 /*
 406  * Create a tracing session that will exclusively be used for snapshot meaning
 407  * the session will be in no output mode and every channel enabled for that
 408  * session will be set in overwrite mode and in mmap output since splice is not
 409  * supported.
 410  *
 411  * If an url is given, it will be used to create a default snapshot output
 412  * using it as a destination. If NULL, no output will be defined and an
 413  * add-output call will be needed.
 414  *
 415  * Name can't be NULL.
 416  */
 417 extern int lttng_create_session_snapshot(const char *name,
 418                 const char *snapshot_url);
 419
 420 /*
 421  * Create a session exclusively used for live reading.
 422  *
 423  * In this mode, the switch-timer parameter is forced for each UST channel, a
 424  * live-switch-timer is enabled for kernel channels, manually setting
 425  * switch-timer is forbidden. Synchronization beacons are sent to the relayd,
 426  * indexes are sent and metadata is checked for each packet.
 427  *
 428  * Returns LTTNG_OK on success or a negative error code.
 429  */
 430 extern int lttng_create_session_live(const char *name, const char *url,
 431                 unsigned int timer_interval);
 432
 433 /*
 434  * Destroy a tracing session.
 435  *
 436  * The session will not be usable anymore, tracing will be stopped for all
 437  * registered traces, and the tracing buffers will be flushed.
 438  *
 439  * The name can't be NULL here.
 440  */
 441 extern int lttng_destroy_session(const char *name);
 442
 443 /*
 444  * List all the tracing sessions.
 445  *
 446  * Return the size (number of entries) of the "lttng_session" array. Caller
 447  * must free(3).
 448  */
 449 extern int lttng_list_sessions(struct lttng_session **sessions);
 450
 451 /*
 452  * List the registered domain(s) of a session.
 453  *
 454  * Return the size (number of entries) of the "lttng_domain" array. Caller
 455  * must free(3).
 456  */
 457 extern int lttng_list_domains(const char *session_name,
 458                 struct lttng_domain **domains);
 459
 460 /*
 461  * List the channel(s) of a session.
 462  *
 463  * Return the size (number of entries) of the "lttng_channel" array. Caller
 464  * must free(3).
 465  */
 466 extern int lttng_list_channels(struct lttng_handle *handle,
 467                 struct lttng_channel **channels);
 468
 469 /*
 470  * List the event(s) of a session channel.
 471  *
 472  * Return the size (number of entries) of the "lttng_event" array.
 473  * Caller must free(3).
 474  */
 475 extern int lttng_list_events(struct lttng_handle *handle,
 476                 const char *channel_name, struct lttng_event **events);
 477
 478 /*
 479  * List the available tracepoints of a specific lttng domain.
 480  *
 481  * Return the size (number of entries) of the "lttng_event" array.
 482  * Caller must free(3).
 483  */
 484 extern int lttng_list_tracepoints(struct lttng_handle *handle,
 485                 struct lttng_event **events);
 486
 487 /*
 488  * List the available tracepoints fields of a specific lttng domain.
 489  *
 490  * Return the size (number of entries) of the "lttng_event_field" array.
 491  * Caller must free(3).
 492  */
 493 extern int lttng_list_tracepoint_fields(struct lttng_handle *handle,
 494                 struct lttng_event_field **fields);
 495
 496 /*
 497  * Check if a session daemon is alive.
 498  *
 499  * Return 1 if alive or 0 if not. On error returns a negative value.
 500  */
 501 extern int lttng_session_daemon_alive(void);
 502
 503 /*
 504  * Set the tracing group for the *current* flow of execution.
 505  *
 506  * On success, returns 0 else a negative value on error being a lttng error
 507  * code found in lttng-error.h
 508  */
 509 extern int lttng_set_tracing_group(const char *name);
 510
 511 /*
 512  * Return a human-readable error message for an lttng-tools error code.
 513  *
 514  * Parameter MUST be a negative value or else you'll get a generic message.
 515  */
 516 extern const char *lttng_strerror(int code);
 517
 518 /*
 519  * This call registers an "outside consumer" for a session and an lttng domain.
 520  * No consumer will be spawned and all fds/commands will go through the socket
 521  * path given (socket_path).
 522  *
 523  * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
 524  * command socket. The error socket is not supported yet for roaming consumers.
 525  */
 526 extern int lttng_register_consumer(struct lttng_handle *handle,
 527                 const char *socket_path);
 528
 529 /*
 530  * Start tracing for *all* registered traces (kernel and user-space).
 531  */
 532 extern int lttng_start_tracing(const char *session_name);
 533
 534 /*
 535  * Stop tracing for *all* registered traces (kernel and user-space).
 536  *
 537  * This call will wait for data availability for each domain of the session so
 538  * this can take an abritrary amount of time. However, when returning you have
 539  * the guarantee that the data is ready to be read and analyse. Use the
 540  * _no_wait call below to avoid this behavior.
 541  *
 542  * The session_name can't be NULL.
 543  */
 544 extern int lttng_stop_tracing(const char *session_name);
 545
 546 /*
 547  * Behave exactly like lttng_stop_tracing but does not wait for data
 548  * availability.
 549  */
 550 extern int lttng_stop_tracing_no_wait(const char *session_name);
 551
 552 /*
 553  * Add context to event(s) for a specific channel (or for all).
 554  *
 555  * If channel_name is NULL, a lookup of the event's channel is done. If both
 556  * are NULL, the context is applied to all events of all channels.
 557  *
 558  * Note that whatever event_name value is, a context can not be added to an
 559  * event, so we just ignore it for now.
 560  */
 561 extern int lttng_add_context(struct lttng_handle *handle,
 562                 struct lttng_event_context *ctx, const char *event_name,
 563                 const char *channel_name);
 564
 565 /*
 566  * Create or enable an event (or events) for a channel.
 567  *
 568  * If the event you are trying to enable does not exist, it will be created,
 569  * else it is enabled.
 570  * If channel_name is NULL, the default channel is used (channel0).
 571  *
 572  * The handle and ev params can not be NULL.
 573  */
 574 extern int lttng_enable_event(struct lttng_handle *handle,
 575                 struct lttng_event *ev, const char *channel_name);
 576
 577 /*
 578  * Create or enable an event with a specific filter.
 579  *
 580  * If the event you are trying to enable does not exist, it will be created,
 581  * else it is enabled.
 582  * If ev is NULL, all events are enabled with that filter.
 583  * If channel_name is NULL, the default channel is used (channel0) and created
 584  * if not found.
 585  * If filter_expression is NULL, an event without associated filter is
 586  * created.
 587  */
 588 extern int lttng_enable_event_with_filter(struct lttng_handle *handle,
 589                 struct lttng_event *event, const char *channel_name,
 590                 const char *filter_expression);
 591
 592 /*
 593  * Create or enable an event with a filter and/or exclusions.
 594  *
 595  * If the event you are trying to enable does not exist, it will be created,
 596  * else it is enabled.
 597  * If ev is NULL, all events are enabled with the filter and exclusion options.
 598  * If channel_name is NULL, the default channel is used (channel0) and created
 599  * if not found.
 600  * If filter_expression is NULL, an event without associated filter is
 601  * created.
 602  * If exclusion count is zero, the event will be created without exclusions.
 603  */
 604 extern int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
 605                 struct lttng_event *event, const char *channel_name,
 606                 const char *filter_expression,
 607                 int exclusion_count, char **exclusion_names);
 608
 609 /*
 610  * Create or enable a channel.
 611  *
 612  * The chan and handle params can not be NULL.
 613  */
 614 extern int lttng_enable_channel(struct lttng_handle *handle,
 615                 struct lttng_channel *chan);
 616
 617 /*
 618  * Disable event(s) of a channel and domain.
 619  *
 620  * If name is NULL, all events are disabled.
 621  * If channel_name is NULL, the default channel is used (channel0).
 622  */
 623 extern int lttng_disable_event(struct lttng_handle *handle,
 624                 const char *name, const char *channel_name);
 625
 626 /*
 627  * Disable channel.
 628  *
 629  */
 630 extern int lttng_disable_channel(struct lttng_handle *handle,
 631                 const char *name);
 632
 633 /*
 634  * Calibrate LTTng overhead.
 635  *
 636  * The chan and handle params can not be NULL.
 637  */
 638 extern int lttng_calibrate(struct lttng_handle *handle,
 639                 struct lttng_calibrate *calibrate);
 640
 641 /*
 642  * Set the default channel attributes for a specific domain and an allocated
 643  * lttng_channel_attr pointer.
 644  *
 645  * If one or both arguments are NULL, nothing happens.
 646  */
 647 extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
 648                 struct lttng_channel_attr *attr);
 649
 650 /*
 651  * Set URL for a consumer for a session and domain.
 652  *
 653  * Both data and control URL must be defined. If both URLs are the same, only
 654  * the control URL is used even for network streaming.
 655  *
 656  * Default port are 5342 and 5343 respectively for control and data which uses
 657  * the TCP protocol.
 658  */
 659 extern int lttng_set_consumer_url(struct lttng_handle *handle,
 660                 const char *control_url, const char *data_url);
 661
 662 /*
 663  * Enable the consumer for a session and domain.
 664  */
 665 extern LTTNG_DEPRECATED("This call is now obsolete.")
 666 int lttng_enable_consumer(struct lttng_handle *handle);
 667
 668 /*
 669  * Disable consumer for a session and domain.
 670  */
 671 extern LTTNG_DEPRECATED("This call is now obsolete.")
 672 int lttng_disable_consumer(struct lttng_handle *handle);
 673
 674 /*
 675  * Check session daemon health for a specific component.
 676  *
 677  * Return 0 if health is OK or 1 if BAD. A returned value of -1 indicate that
 678  * the control library was not able to connect to the session daemon health
 679  * socket.
 680  *
 681  * Any other positive value is an lttcomm error which can be translate with
 682  * lttng_strerror().
 683  *
 684  * Please see lttng-health-check(3) man page for more information.
 685  */
 686 extern LTTNG_DEPRECATED("This call is now obsolete.")
 687 int lttng_health_check(enum lttng_health_component c);
 688
 689 /*
 690  * For a given session name, this call checks if the data is ready to be read
 691  * or is still being extracted by the consumer(s) (pending) hence not ready to
 692  * be used by any readers.
 693  *
 694  * Return 0 if there is _no_ data pending in the buffers thus having a
 695  * guarantee that the data can be read safely. Else, return 1 if there is still
 696  * traced data is pending. On error, a negative value is returned and readable
 697  * by lttng_strerror().
 698  */
 699 extern int lttng_data_pending(const char *session_name);
 700
 701 #ifdef __cplusplus
 702 }
 703 #endif
 704
 705 #endif /* LTTNG_H */