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