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