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 /*
  30  * Event symbol length. Copied from LTTng kernel ABI.
  31  */
  32 #define LTTNG_SYMBOL_NAME_LEN             256
  33
  34 /*
  35  * Every lttng_event_* structure both apply to kernel event and user-space
  36  * event.
  37  */
  38
  39 /*
  40  * Domain types: the different possible tracers.
  41  */
  42 enum lttng_domain_type {
  43         LTTNG_DOMAIN_KERNEL                   = 1,
  44         LTTNG_DOMAIN_UST                      = 2,
  45
  46         /*
  47          * For now, the domains below are not implemented. However, we keep them
  48          * here in order to retain their enum values for future development. Note
  49          * that it is on the roadmap to implement them.
  50          *
  51         LTTNG_DOMAIN_UST_EXEC_NAME            = 3,
  52         LTTNG_DOMAIN_UST_PID                  = 4,
  53         LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN  = 5,
  54         */
  55 };
  56
  57 /*
  58  * Instrumentation type of tracing event.
  59  */
  60 enum lttng_event_type {
  61         LTTNG_EVENT_ALL                       = -1,
  62         LTTNG_EVENT_TRACEPOINT                = 0,
  63         LTTNG_EVENT_PROBE                     = 1,
  64         LTTNG_EVENT_FUNCTION                  = 2,
  65         LTTNG_EVENT_FUNCTION_ENTRY            = 3,
  66         LTTNG_EVENT_NOOP                      = 4,
  67         LTTNG_EVENT_SYSCALL                   = 5,
  68 };
  69
  70 /*
  71  * Loglevel information.
  72  */
  73 enum lttng_loglevel_type {
  74         LTTNG_EVENT_LOGLEVEL_ALL              = 0,
  75         LTTNG_EVENT_LOGLEVEL_RANGE            = 1,
  76         LTTNG_EVENT_LOGLEVEL_SINGLE           = 2,
  77 };
  78
  79 /*
  80  * Available loglevels.
  81  */
  82 enum lttng_loglevel {
  83         LTTNG_LOGLEVEL_EMERG                  = 0,
  84         LTTNG_LOGLEVEL_ALERT                  = 1,
  85         LTTNG_LOGLEVEL_CRIT                   = 2,
  86         LTTNG_LOGLEVEL_ERR                    = 3,
  87         LTTNG_LOGLEVEL_WARNING                = 4,
  88         LTTNG_LOGLEVEL_NOTICE                 = 5,
  89         LTTNG_LOGLEVEL_INFO                   = 6,
  90         LTTNG_LOGLEVEL_DEBUG_SYSTEM           = 7,
  91         LTTNG_LOGLEVEL_DEBUG_PROGRAM          = 8,
  92         LTTNG_LOGLEVEL_DEBUG_PROCESS          = 9,
  93         LTTNG_LOGLEVEL_DEBUG_MODULE           = 10,
  94         LTTNG_LOGLEVEL_DEBUG_UNIT             = 11,
  95         LTTNG_LOGLEVEL_DEBUG_FUNCTION         = 12,
  96         LTTNG_LOGLEVEL_DEBUG_LINE             = 13,
  97         LTTNG_LOGLEVEL_DEBUG                  = 14,
  98 };
  99
 100 /*
 101  * LTTng consumer mode
 102  */
 103 enum lttng_event_output {
 104         LTTNG_EVENT_SPLICE                    = 0,
 105         LTTNG_EVENT_MMAP                      = 1,
 106 };
 107
 108 /* Event context possible type */
 109 enum lttng_event_context_type {
 110         LTTNG_EVENT_CONTEXT_PID               = 0,
 111         LTTNG_EVENT_CONTEXT_PERF_COUNTER      = 1,
 112         LTTNG_EVENT_CONTEXT_PROCNAME          = 2,
 113         LTTNG_EVENT_CONTEXT_PRIO              = 3,
 114         LTTNG_EVENT_CONTEXT_NICE              = 4,
 115         LTTNG_EVENT_CONTEXT_VPID              = 5,
 116         LTTNG_EVENT_CONTEXT_TID               = 6,
 117         LTTNG_EVENT_CONTEXT_VTID              = 7,
 118         LTTNG_EVENT_CONTEXT_PPID              = 8,
 119         LTTNG_EVENT_CONTEXT_VPPID             = 9,
 120         LTTNG_EVENT_CONTEXT_PTHREAD_ID        = 10,
 121 };
 122
 123 enum lttng_calibrate_type {
 124         LTTNG_CALIBRATE_FUNCTION              = 0,
 125 };
 126
 127 /*
 128  * The structures should be initialized to zero before use.
 129  */
 130 #define LTTNG_DOMAIN_PADDING1              16
 131 #define LTTNG_DOMAIN_PADDING2              LTTNG_SYMBOL_NAME_LEN + 32
 132 struct lttng_domain {
 133         enum lttng_domain_type type;
 134         char padding[LTTNG_DOMAIN_PADDING1];
 135
 136         union {
 137                 pid_t pid;
 138                 char exec_name[NAME_MAX];
 139                 char padding[LTTNG_DOMAIN_PADDING2];
 140         } attr;
 141 };
 142
 143 /*
 144  * Perf counter attributes
 145  *
 146  * The structures should be initialized to zero before use.
 147  */
 148 #define LTTNG_PERF_EVENT_PADDING1          16
 149 struct lttng_event_perf_counter_ctx {
 150         uint32_t type;
 151         uint64_t config;
 152         char name[LTTNG_SYMBOL_NAME_LEN];
 153
 154         char padding[LTTNG_PERF_EVENT_PADDING1];
 155 };
 156
 157 /*
 158  * Event/channel context
 159  *
 160  * The structures should be initialized to zero before use.
 161  */
 162 #define LTTNG_EVENT_CONTEXT_PADDING1       16
 163 #define LTTNG_EVENT_CONTEXT_PADDING2       LTTNG_SYMBOL_NAME_LEN + 32
 164 struct lttng_event_context {
 165         enum lttng_event_context_type ctx;
 166         char padding[LTTNG_EVENT_CONTEXT_PADDING1];
 167
 168         union {
 169                 struct lttng_event_perf_counter_ctx perf_counter;
 170                 char padding[LTTNG_EVENT_CONTEXT_PADDING2];
 171         } u;
 172 };
 173
 174 /*
 175  * Event probe.
 176  *
 177  * Either addr is used or symbol_name and offset.
 178  *
 179  * The structures should be initialized to zero before use.
 180  */
 181 #define LTTNG_EVENT_PROBE_PADDING1         16
 182 struct lttng_event_probe_attr {
 183         uint64_t addr;
 184
 185         uint64_t offset;
 186         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 187
 188         char padding[LTTNG_EVENT_PROBE_PADDING1];
 189 };
 190
 191 /*
 192  * Function tracer
 193  *
 194  * The structures should be initialized to zero before use.
 195  */
 196 #define LTTNG_EVENT_FUNCTION_PADDING1      16
 197 struct lttng_event_function_attr {
 198         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 199
 200         char padding[LTTNG_EVENT_FUNCTION_PADDING1];
 201 };
 202
 203 /*
 204  * Generic lttng event
 205  *
 206  * The structures should be initialized to zero before use.
 207  */
 208 #define LTTNG_EVENT_PADDING1               16
 209 #define LTTNG_EVENT_PADDING2               LTTNG_SYMBOL_NAME_LEN + 32
 210 struct lttng_event {
 211         enum lttng_event_type type;
 212         char name[LTTNG_SYMBOL_NAME_LEN];
 213
 214         enum lttng_loglevel_type loglevel_type;
 215         int loglevel;
 216
 217         uint32_t enabled;
 218         pid_t pid;
 219
 220         char padding[LTTNG_EVENT_PADDING1];
 221
 222         /* Per event type configuration */
 223         union {
 224                 struct lttng_event_probe_attr probe;
 225                 struct lttng_event_function_attr ftrace;
 226
 227                 char padding[LTTNG_EVENT_PADDING2];
 228         } attr;
 229 };
 230
 231 enum lttng_event_field_type {
 232         LTTNG_EVENT_FIELD_OTHER                 = 0,
 233         LTTNG_EVENT_FIELD_INTEGER               = 1,
 234         LTTNG_EVENT_FIELD_ENUM                  = 2,
 235         LTTNG_EVENT_FIELD_FLOAT                 = 3,
 236         LTTNG_EVENT_FIELD_STRING                = 4,
 237 };
 238
 239 #define LTTNG_EVENT_FIELD_PADDING       LTTNG_SYMBOL_NAME_LEN + 32
 240 struct lttng_event_field {
 241         char field_name[LTTNG_SYMBOL_NAME_LEN];
 242         enum lttng_event_field_type type;
 243         char padding[LTTNG_EVENT_FIELD_PADDING];
 244         struct lttng_event event;
 245 };
 246
 247 /*
 248  * Tracer channel attributes. For both kernel and user-space.
 249  *
 250  * The structures should be initialized to zero before use.
 251  */
 252 #define LTTNG_CHANNEL_ATTR_PADDING1        LTTNG_SYMBOL_NAME_LEN + 32
 253 struct lttng_channel_attr {
 254         int overwrite;                      /* 1: overwrite, 0: discard */
 255         uint64_t subbuf_size;               /* bytes */
 256         uint64_t num_subbuf;                /* power of 2 */
 257         unsigned int switch_timer_interval; /* usec */
 258         unsigned int read_timer_interval;   /* usec */
 259         enum lttng_event_output output;     /* splice, mmap */
 260
 261         char padding[LTTNG_CHANNEL_ATTR_PADDING1];
 262 };
 263
 264 /*
 265  * Channel information structure. For both kernel and user-space.
 266  *
 267  * The structures should be initialized to zero before use.
 268  */
 269 #define LTTNG_CHANNEL_PADDING1             16
 270 struct lttng_channel {
 271         char name[LTTNG_SYMBOL_NAME_LEN];
 272         uint32_t enabled;
 273         struct lttng_channel_attr attr;
 274
 275         char padding[LTTNG_CHANNEL_PADDING1];
 276 };
 277
 278 #define LTTNG_CALIBRATE_PADDING1           16
 279 struct lttng_calibrate {
 280         enum lttng_calibrate_type type;
 281
 282         char padding[LTTNG_CALIBRATE_PADDING1];
 283 };
 284
 285 /*
 286  * Basic session information.
 287  *
 288  * This is an 'output data' meaning that it only comes *from* the session
 289  * daemon *to* the lttng client. It's basically a 'human' representation of
 290  * tracing entities (here a session).
 291  *
 292  * The structures should be initialized to zero before use.
 293  */
 294 #define LTTNG_SESSION_PADDING1             16
 295 struct lttng_session {
 296         char name[NAME_MAX];
 297         /* The path where traces are written */
 298         char path[PATH_MAX];
 299         uint32_t enabled;       /* enabled/started: 1, disabled/stopped: 0 */
 300
 301         char padding[LTTNG_SESSION_PADDING1];
 302 };
 303
 304 /*
 305  * Handle used as a context for commands.
 306  *
 307  * The structures should be initialized to zero before use.
 308  */
 309 #define LTTNG_HANDLE_PADDING1              16
 310 struct lttng_handle {
 311         char session_name[NAME_MAX];
 312         struct lttng_domain domain;
 313
 314         char padding[LTTNG_HANDLE_PADDING1];
 315 };
 316
 317 /*
 318  * Public LTTng control API
 319  *
 320  * For functions having an lttng domain type as parameter, if a bad value is
 321  * given, NO default is applied and an error is returned.
 322  *
 323  * On success, all functions of the API return 0 or the size of the allocated
 324  * array (in bytes).
 325  *
 326  * On error, a negative value is returned being a specific lttng-tools error
 327  * code which can be humanly interpreted with lttng_strerror(err).
 328  *
 329  * Exceptions to this are noted below.
 330  */
 331
 332 /*
 333  * Create a handle used as a context for every request made to the library.
 334  *
 335  * This handle contains the session name and lttng domain on which the command
 336  * will be executed.
 337  * The returned pointer will be NULL in case of malloc() error.
 338  */
 339 extern struct lttng_handle *lttng_create_handle(const char *session_name,
 340                 struct lttng_domain *domain);
 341
 342 /*
 343  * Destroy a handle. This will simply free(3) the data pointer returned by
 344  * lttng_create_handle(), rendering it unusable.
 345  */
 346 extern void lttng_destroy_handle(struct lttng_handle *handle);
 347
 348 /*
 349  * Create a tracing session using a name and a path where the trace will be
 350  * written.
 351  */
 352 extern int lttng_create_session(const char *name, const char *path);
 353
 354 /*
 355  * Destroy a tracing session.
 356  *
 357  * The session will not be usable anymore, tracing will be stopped for all
 358  * registered traces, and the tracing buffers will be flushed.
 359  */
 360 extern int lttng_destroy_session(const char *name);
 361
 362 /*
 363  * List all the tracing sessions.
 364  *
 365  * Return the size (number of entries) of the "lttng_session" array. Caller
 366  * must free(3).
 367  */
 368 extern int lttng_list_sessions(struct lttng_session **sessions);
 369
 370 /*
 371  * List the registered domain(s) of a session.
 372  *
 373  * Return the size (number of entries) of the "lttng_domain" array. Caller
 374  * must free(3).
 375  */
 376 extern int lttng_list_domains(const char *session_name,
 377                 struct lttng_domain **domains);
 378
 379 /*
 380  * List the channel(s) of a session.
 381  *
 382  * Return the size (number of entries) of the "lttng_channel" array. Caller
 383  * must free(3).
 384  */
 385 extern int lttng_list_channels(struct lttng_handle *handle,
 386                 struct lttng_channel **channels);
 387
 388 /*
 389  * List the event(s) of a session channel.
 390  *
 391  * Return the size (number of entries) of the "lttng_event" array.
 392  * Caller must free(3).
 393  */
 394 extern int lttng_list_events(struct lttng_handle *handle,
 395                 const char *channel_name, struct lttng_event **events);
 396
 397 /*
 398  * List the available tracepoints of a specific lttng domain.
 399  *
 400  * Return the size (number of entries) of the "lttng_event" array.
 401  * Caller must free(3).
 402  */
 403 extern int lttng_list_tracepoints(struct lttng_handle *handle,
 404                 struct lttng_event **events);
 405
 406 /*
 407  * List the available tracepoints fields of a specific lttng domain.
 408  *
 409  * Return the size (number of entries) of the "lttng_event_field" array.
 410  * Caller must free(3).
 411  */
 412 extern int lttng_list_tracepoint_fields(struct lttng_handle *handle,
 413                 struct lttng_event_field **fields);
 414
 415 /*
 416  * Check if a session daemon is alive.
 417  *
 418  * Return 1 if alive or 0 if not. On error returns a negative value.
 419  */
 420 extern int lttng_session_daemon_alive(void);
 421
 422 /*
 423  * Set the tracing group for the *current* flow of execution.
 424  *
 425  * On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
 426  */
 427 extern int lttng_set_tracing_group(const char *name);
 428
 429 /*
 430  * Return a human-readable error message for an lttng-tools error code.
 431  *
 432  * Parameter MUST be a negative value or else you'll get a generic message.
 433  */
 434 extern const char *lttng_strerror(int code);
 435
 436 /*
 437  * This call registers an "outside consumer" for a session and an lttng domain.
 438  * No consumer will be spawned and all fds/commands will go through the socket
 439  * path given (socket_path).
 440  *
 441  * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
 442  * command socket. The error socket is not supported yet for roaming consumers.
 443  */
 444 extern int lttng_register_consumer(struct lttng_handle *handle,
 445                 const char *socket_path);
 446
 447 /*
 448  * Start tracing for *all* registered traces (kernel and user-space).
 449  */
 450 extern int lttng_start_tracing(const char *session_name);
 451
 452 /*
 453  * Stop tracing for *all* registered traces (kernel and user-space).
 454  */
 455 extern int lttng_stop_tracing(const char *session_name);
 456
 457 /*
 458  * Add context to event(s) for a specific channel (or for all).
 459  *
 460  * If event_name is NULL, the context is applied to all events of the channel.
 461  * If channel_name is NULL, a lookup of the event's channel is done.
 462  * If both are NULL, the context is applied to all events of all channels.
 463  */
 464 extern int lttng_add_context(struct lttng_handle *handle,
 465                 struct lttng_event_context *ctx, const char *event_name,
 466                 const char *channel_name);
 467
 468 /*
 469  * Create or enable an event (or events) for a channel.
 470  *
 471  * If the event you are trying to enable does not exist, it will be created,
 472  * else it is enabled.
 473  * If event_name is NULL, all events are enabled.
 474  * If channel_name is NULL, the default channel is used (channel0).
 475  */
 476 extern int lttng_enable_event(struct lttng_handle *handle,
 477                 struct lttng_event *ev, const char *channel_name);
 478
 479 /*
 480  * Create or enable a channel.
 481  * The channel name cannot be NULL.
 482  */
 483 extern int lttng_enable_channel(struct lttng_handle *handle,
 484                 struct lttng_channel *chan);
 485
 486 /*
 487  * Disable event(s) of a channel and domain.
 488  *
 489  * If event_name is NULL, all events are disabled.
 490  * If channel_name is NULL, the default channel is used (channel0).
 491  */
 492 extern int lttng_disable_event(struct lttng_handle *handle,
 493                 const char *name, const char *channel_name);
 494
 495 /*
 496  * Disable channel.
 497  *
 498  * The channel name cannot be NULL.
 499  */
 500 extern int lttng_disable_channel(struct lttng_handle *handle,
 501                 const char *name);
 502
 503 /*
 504  * Calibrate LTTng overhead.
 505  */
 506 extern int lttng_calibrate(struct lttng_handle *handle,
 507                 struct lttng_calibrate *calibrate);
 508
 509 /*
 510  * Set the default channel attributes for a specific domain and an allocated
 511  * lttng_channel_attr pointer.
 512  *
 513  * If either or both of the arguments are NULL, nothing happens.
 514  */
 515 extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
 516                 struct lttng_channel_attr *attr);
 517
 518 #endif /* _LTTNG_H */