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