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