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