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 /*
 232  * Tracer channel attributes. For both kernel and user-space.
 233  *
 234  * The structures should be initialized to zero before use.
 235  */
 236 #define LTTNG_CHANNEL_ATTR_PADDING1        LTTNG_SYMBOL_NAME_LEN + 32
 237 struct lttng_channel_attr {
 238         int overwrite;                      /* 1: overwrite, 0: discard */
 239         uint64_t subbuf_size;               /* bytes */
 240         uint64_t num_subbuf;                /* power of 2 */
 241         unsigned int switch_timer_interval; /* usec */
 242         unsigned int read_timer_interval;   /* usec */
 243         enum lttng_event_output output;     /* splice, mmap */
 244
 245         char padding[LTTNG_CHANNEL_ATTR_PADDING1];
 246 };
 247
 248 /*
 249  * Channel information structure. For both kernel and user-space.
 250  *
 251  * The structures should be initialized to zero before use.
 252  */
 253 #define LTTNG_CHANNEL_PADDING1             16
 254 struct lttng_channel {
 255         char name[LTTNG_SYMBOL_NAME_LEN];
 256         uint32_t enabled;
 257         struct lttng_channel_attr attr;
 258
 259         char padding[LTTNG_CHANNEL_PADDING1];
 260 };
 261
 262 #define LTTNG_CALIBRATE_PADDING1           16
 263 struct lttng_calibrate {
 264         enum lttng_calibrate_type type;
 265
 266         char padding[LTTNG_CALIBRATE_PADDING1];
 267 };
 268
 269 /*
 270  * Basic session information.
 271  *
 272  * This is an 'output data' meaning that it only comes *from* the session
 273  * daemon *to* the lttng client. It's basically a 'human' representation of
 274  * tracing entities (here a session).
 275  *
 276  * The structures should be initialized to zero before use.
 277  */
 278 #define LTTNG_SESSION_PADDING1             16
 279 struct lttng_session {
 280         char name[NAME_MAX];
 281         /* The path where traces are written */
 282         char path[PATH_MAX];
 283         uint32_t enabled;       /* enabled/started: 1, disabled/stopped: 0 */
 284
 285         char padding[LTTNG_SESSION_PADDING1];
 286 };
 287
 288 /*
 289  * Handle used as a context for commands.
 290  *
 291  * The structures should be initialized to zero before use.
 292  */
 293 #define LTTNG_HANDLE_PADDING1              16
 294 struct lttng_handle {
 295         char session_name[NAME_MAX];
 296         struct lttng_domain domain;
 297
 298         char padding[LTTNG_HANDLE_PADDING1];
 299 };
 300
 301 /*
 302  * Public LTTng control API
 303  *
 304  * For functions having an lttng domain type as parameter, if a bad value is
 305  * given, NO default is applied and an error is returned.
 306  *
 307  * On success, all functions of the API return 0 or the size of the allocated
 308  * array (in bytes).
 309  *
 310  * On error, a negative value is returned being a specific lttng-tools error
 311  * code which can be humanly interpreted with lttng_strerror(err).
 312  *
 313  * Exceptions to this are noted below.
 314  */
 315
 316 /*
 317  * Create a handle used as a context for every request made to the library.
 318  *
 319  * This handle contains the session name and lttng domain on which the command
 320  * will be executed.
 321  * The returned pointer will be NULL in case of malloc() error.
 322  */
 323 extern struct lttng_handle *lttng_create_handle(const char *session_name,
 324                 struct lttng_domain *domain);
 325
 326 /*
 327  * Destroy a handle. This will simply free(3) the data pointer returned by
 328  * lttng_create_handle(), rendering it unusable.
 329  */
 330 extern void lttng_destroy_handle(struct lttng_handle *handle);
 331
 332 /*
 333  * Create a tracing session using a name and a path where the trace will be
 334  * written.
 335  */
 336 extern int lttng_create_session(const char *name, const char *path);
 337
 338 /*
 339  * Destroy a tracing session.
 340  *
 341  * The session will not be usable anymore, tracing will be stopped for all
 342  * registered traces, and the tracing buffers will be flushed.
 343  */
 344 extern int lttng_destroy_session(const char *name);
 345
 346 /*
 347  * List all the tracing sessions.
 348  *
 349  * Return the size (number of entries) of the "lttng_session" array. Caller
 350  * must free(3).
 351  */
 352 extern int lttng_list_sessions(struct lttng_session **sessions);
 353
 354 /*
 355  * List the registered domain(s) of a session.
 356  *
 357  * Return the size (number of entries) of the "lttng_domain" array. Caller
 358  * must free(3).
 359  */
 360 extern int lttng_list_domains(const char *session_name,
 361                 struct lttng_domain **domains);
 362
 363 /*
 364  * List the channel(s) of a session.
 365  *
 366  * Return the size (number of entries) of the "lttng_channel" array. Caller
 367  * must free(3).
 368  */
 369 extern int lttng_list_channels(struct lttng_handle *handle,
 370                 struct lttng_channel **channels);
 371
 372 /*
 373  * List the event(s) of a session channel.
 374  *
 375  * Return the size (number of entries) of the "lttng_event" array.
 376  * Caller must free(3).
 377  */
 378 extern int lttng_list_events(struct lttng_handle *handle,
 379                 const char *channel_name, struct lttng_event **events);
 380
 381 /*
 382  * List the available tracepoints of a specific lttng domain.
 383  *
 384  * Return the size (number of entries) of the "lttng_event" array.
 385  * Caller must free(3).
 386  */
 387 extern int lttng_list_tracepoints(struct lttng_handle *handle,
 388                 struct lttng_event **events);
 389
 390 /*
 391  * Check if a session daemon is alive.
 392  *
 393  * Return 1 if alive or 0 if not. On error returns a negative value.
 394  */
 395 extern int lttng_session_daemon_alive(void);
 396
 397 /*
 398  * Set the tracing group for the *current* flow of execution.
 399  *
 400  * On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
 401  */
 402 extern int lttng_set_tracing_group(const char *name);
 403
 404 /*
 405  * Return a human-readable error message for an lttng-tools error code.
 406  *
 407  * Parameter MUST be a negative value or else you'll get a generic message.
 408  */
 409 extern const char *lttng_strerror(int code);
 410
 411 /*
 412  * This call registers an "outside consumer" for a session and an lttng domain.
 413  * No consumer will be spawned and all fds/commands will go through the socket
 414  * path given (socket_path).
 415  *
 416  * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
 417  * command socket. The error socket is not supported yet for roaming consumers.
 418  */
 419 extern int lttng_register_consumer(struct lttng_handle *handle,
 420                 const char *socket_path);
 421
 422 /*
 423  * Start tracing for *all* registered traces (kernel and user-space).
 424  */
 425 extern int lttng_start_tracing(const char *session_name);
 426
 427 /*
 428  * Stop tracing for *all* registered traces (kernel and user-space).
 429  */
 430 extern int lttng_stop_tracing(const char *session_name);
 431
 432 /*
 433  * Add context to event(s) for a specific channel (or for all).
 434  *
 435  * If event_name is NULL, the context is applied to all events of the channel.
 436  * If channel_name is NULL, a lookup of the event's channel is done.
 437  * If both are NULL, the context is applied to all events of all channels.
 438  */
 439 extern int lttng_add_context(struct lttng_handle *handle,
 440                 struct lttng_event_context *ctx, const char *event_name,
 441                 const char *channel_name);
 442
 443 /*
 444  * Create or enable an event (or events) for a channel.
 445  *
 446  * If the event you are trying to enable does not exist, it will be created,
 447  * else it is enabled.
 448  * If event_name is NULL, all events are enabled.
 449  * If channel_name is NULL, the default channel is used (channel0).
 450  */
 451 extern int lttng_enable_event(struct lttng_handle *handle,
 452                 struct lttng_event *ev, const char *channel_name);
 453
 454 /*
 455  * Create or enable a channel.
 456  * The channel name cannot be NULL.
 457  */
 458 extern int lttng_enable_channel(struct lttng_handle *handle,
 459                 struct lttng_channel *chan);
 460
 461 /*
 462  * Disable event(s) of a channel and domain.
 463  *
 464  * If event_name is NULL, all events are disabled.
 465  * If channel_name is NULL, the default channel is used (channel0).
 466  */
 467 extern int lttng_disable_event(struct lttng_handle *handle,
 468                 const char *name, const char *channel_name);
 469
 470 /*
 471  * Disable channel.
 472  *
 473  * The channel name cannot be NULL.
 474  */
 475 extern int lttng_disable_channel(struct lttng_handle *handle,
 476                 const char *name);
 477
 478 /*
 479  * Calibrate LTTng overhead.
 480  */
 481 extern int lttng_calibrate(struct lttng_handle *handle,
 482                 struct lttng_calibrate *calibrate);
 483
 484 /*
 485  * Set the default channel attributes for a specific domain and an allocated
 486  * lttng_channel_attr pointer.
 487  *
 488  * If either or both of the arguments are NULL, nothing happens.
 489  */
 490 extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
 491                 struct lttng_channel_attr *attr);
 492
 493 #endif /* _LTTNG_H */