05ba6d3a812eea5b3b24e5458b913e2d051851e7
[lttng-tools.git] / 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 as published by the
10 * Free Software Foundation; only version 2.1 of the License.
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 #define LTTNG_DOMAIN_PADDING1 16
128 #define LTTNG_DOMAIN_PADDING2 LTTNG_SYMBOL_NAME_LEN + 32
129 struct lttng_domain {
130 enum lttng_domain_type type;
131 char padding[LTTNG_DOMAIN_PADDING1];
132
133 union {
134 pid_t pid;
135 char exec_name[NAME_MAX];
136 char padding[LTTNG_DOMAIN_PADDING2];
137 } attr;
138 };
139
140 /* Perf counter attributes */
141 #define LTTNG_PERF_EVENT_PADDING1 16
142 struct lttng_event_perf_counter_ctx {
143 uint32_t type;
144 uint64_t config;
145 char name[LTTNG_SYMBOL_NAME_LEN];
146
147 char padding[LTTNG_PERF_EVENT_PADDING1];
148 };
149
150 /* Event/Channel context */
151 #define LTTNG_EVENT_CONTEXT_PADDING1 16
152 #define LTTNG_EVENT_CONTEXT_PADDING2 LTTNG_SYMBOL_NAME_LEN + 32
153 struct lttng_event_context {
154 enum lttng_event_context_type ctx;
155 char padding[LTTNG_EVENT_CONTEXT_PADDING1];
156
157 union {
158 struct lttng_event_perf_counter_ctx perf_counter;
159 char padding[LTTNG_EVENT_CONTEXT_PADDING2];
160 } u;
161 };
162
163 /*
164 * Event probe.
165 *
166 * Either addr is used or symbol_name and offset.
167 */
168 #define LTTNG_EVENT_PROBE_PADDING1 16
169 struct lttng_event_probe_attr {
170 uint64_t addr;
171
172 uint64_t offset;
173 char symbol_name[LTTNG_SYMBOL_NAME_LEN];
174
175 char padding[LTTNG_EVENT_PROBE_PADDING1];
176 };
177
178 /*
179 * Function tracer
180 */
181 #define LTTNG_EVENT_FUNCTION_PADDING1 16
182 struct lttng_event_function_attr {
183 char symbol_name[LTTNG_SYMBOL_NAME_LEN];
184
185 char padding[LTTNG_EVENT_FUNCTION_PADDING1];
186 };
187
188 /*
189 * Generic lttng event
190 */
191 #define LTTNG_EVENT_PADDING1 16
192 #define LTTNG_EVENT_PADDING2 LTTNG_SYMBOL_NAME_LEN + 32
193 struct lttng_event {
194 enum lttng_event_type type;
195 char name[LTTNG_SYMBOL_NAME_LEN];
196
197 enum lttng_loglevel_type loglevel_type;
198 int loglevel;
199
200 uint32_t enabled;
201 pid_t pid;
202
203 char padding[LTTNG_EVENT_PADDING1];
204
205 /* Per event type configuration */
206 union {
207 struct lttng_event_probe_attr probe;
208 struct lttng_event_function_attr ftrace;
209
210 char padding[LTTNG_EVENT_PADDING2];
211 } attr;
212 };
213
214 /*
215 * Tracer channel attributes. For both kernel and user-space.
216 */
217 #define LTTNG_CHANNEL_ATTR_PADDING1 LTTNG_SYMBOL_NAME_LEN + 32
218 struct lttng_channel_attr {
219 int overwrite; /* 1: overwrite, 0: discard */
220 uint64_t subbuf_size; /* bytes */
221 uint64_t num_subbuf; /* power of 2 */
222 unsigned int switch_timer_interval; /* usec */
223 unsigned int read_timer_interval; /* usec */
224 enum lttng_event_output output; /* splice, mmap */
225
226 char padding[LTTNG_CHANNEL_ATTR_PADDING1];
227 };
228
229 /*
230 * Channel information structure. For both kernel and user-space.
231 */
232 #define LTTNG_CHANNEL_PADDING1 16
233 struct lttng_channel {
234 char name[LTTNG_SYMBOL_NAME_LEN];
235 uint32_t enabled;
236 struct lttng_channel_attr attr;
237
238 char padding[LTTNG_CHANNEL_PADDING1];
239 };
240
241 #define LTTNG_CALIBRATE_PADDING1 16
242 struct lttng_calibrate {
243 enum lttng_calibrate_type type;
244
245 char padding[LTTNG_CALIBRATE_PADDING1];
246 };
247
248 /*
249 * Basic session information.
250 *
251 * This is an 'output data' meaning that it only comes *from* the session
252 * daemon *to* the lttng client. It's basically a 'human' representation of
253 * tracing entities (here a session).
254 */
255 #define LTTNG_SESSION_PADDING1 16
256 struct lttng_session {
257 char name[NAME_MAX];
258 /* The path where traces are written */
259 char path[PATH_MAX];
260 uint32_t enabled; /* enabled/started: 1, disabled/stopped: 0 */
261
262 char padding[LTTNG_SESSION_PADDING1];
263 };
264
265 /*
266 * Handle used as a context for commands.
267 */
268 #define LTTNG_HANDLE_PADDING1 16
269 struct lttng_handle {
270 char session_name[NAME_MAX];
271 struct lttng_domain domain;
272
273 char padding[LTTNG_HANDLE_PADDING1];
274 };
275
276 /*
277 * Public LTTng control API
278 *
279 * For functions having an lttng domain type as parameter, if a bad value is
280 * given, NO default is applied and an error is returned.
281 *
282 * On success, all functions of the API return 0 or the size of the allocated
283 * array (in bytes).
284 *
285 * On error, a negative value is returned being a specific lttng-tools error
286 * code which can be humanly interpreted with lttng_strerror(err).
287 *
288 * Exceptions to this are noted below.
289 */
290
291 /*
292 * Create a handle used as a context for every request made to the library.
293 *
294 * This handle contains the session name and lttng domain on which the command
295 * will be executed.
296 * The returned pointer will be NULL in case of malloc() error.
297 */
298 extern struct lttng_handle *lttng_create_handle(const char *session_name,
299 struct lttng_domain *domain);
300
301 /*
302 * Destroy a handle. This will simply free(3) the data pointer returned by
303 * lttng_create_handle(), rendering it unusable.
304 */
305 extern void lttng_destroy_handle(struct lttng_handle *handle);
306
307 /*
308 * Create a tracing session using a name and a path where the trace will be
309 * written.
310 */
311 extern int lttng_create_session(const char *name, const char *path);
312
313 /*
314 * Destroy a tracing session.
315 *
316 * The session will not be usable anymore, tracing will be stopped for all
317 * registered traces, and the tracing buffers will be flushed.
318 */
319 extern int lttng_destroy_session(const char *name);
320
321 /*
322 * List all the tracing sessions.
323 *
324 * Return the size (number of entries) of the "lttng_session" array. Caller
325 * must free(3).
326 */
327 extern int lttng_list_sessions(struct lttng_session **sessions);
328
329 /*
330 * List the registered domain(s) of a session.
331 *
332 * Return the size (number of entries) of the "lttng_domain" array. Caller
333 * must free(3).
334 */
335 extern int lttng_list_domains(const char *session_name,
336 struct lttng_domain **domains);
337
338 /*
339 * List the channel(s) of a session.
340 *
341 * Return the size (number of entries) of the "lttng_channel" array. Caller
342 * must free(3).
343 */
344 extern int lttng_list_channels(struct lttng_handle *handle,
345 struct lttng_channel **channels);
346
347 /*
348 * List the event(s) of a session channel.
349 *
350 * Return the size (number of entries) of the "lttng_event" array.
351 * Caller must free(3).
352 */
353 extern int lttng_list_events(struct lttng_handle *handle,
354 const char *channel_name, struct lttng_event **events);
355
356 /*
357 * List the available tracepoints of a specific lttng domain.
358 *
359 * Return the size (number of entries) of the "lttng_event" array.
360 * Caller must free(3).
361 */
362 extern int lttng_list_tracepoints(struct lttng_handle *handle,
363 struct lttng_event **events);
364
365 /*
366 * Check if a session daemon is alive.
367 *
368 * Return 1 if alive or 0 if not. On error returns a negative value.
369 */
370 extern int lttng_session_daemon_alive(void);
371
372 /*
373 * Set the tracing group for the *current* flow of execution.
374 *
375 * On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
376 */
377 extern int lttng_set_tracing_group(const char *name);
378
379 /*
380 * Return a human-readable error message for an lttng-tools error code.
381 *
382 * Parameter MUST be a negative value or else you'll get a generic message.
383 */
384 extern const char *lttng_strerror(int code);
385
386 /*
387 * This call registers an "outside consumer" for a session and an lttng domain.
388 * No consumer will be spawned and all fds/commands will go through the socket
389 * path given (socket_path).
390 *
391 * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
392 * command socket. The error socket is not supported yet for roaming consumers.
393 */
394 extern int lttng_register_consumer(struct lttng_handle *handle,
395 const char *socket_path);
396
397 /*
398 * Start tracing for *all* registered traces (kernel and user-space).
399 */
400 extern int lttng_start_tracing(const char *session_name);
401
402 /*
403 * Stop tracing for *all* registered traces (kernel and user-space).
404 */
405 extern int lttng_stop_tracing(const char *session_name);
406
407 /*
408 * Add context to event(s) for a specific channel (or for all).
409 *
410 * If event_name is NULL, the context is applied to all events of the channel.
411 * If channel_name is NULL, a lookup of the event's channel is done.
412 * If both are NULL, the context is applied to all events of all channels.
413 */
414 extern int lttng_add_context(struct lttng_handle *handle,
415 struct lttng_event_context *ctx, const char *event_name,
416 const char *channel_name);
417
418 /*
419 * Create or enable an event (or events) for a channel.
420 *
421 * If the event you are trying to enable does not exist, it will be created,
422 * else it is enabled.
423 * If event_name is NULL, all events are enabled.
424 * If channel_name is NULL, the default channel is used (channel0).
425 */
426 extern int lttng_enable_event(struct lttng_handle *handle,
427 struct lttng_event *ev, const char *channel_name);
428
429 /*
430 * Create or enable a channel.
431 * The channel name cannot be NULL.
432 */
433 extern int lttng_enable_channel(struct lttng_handle *handle,
434 struct lttng_channel *chan);
435
436 /*
437 * Disable event(s) of a channel and domain.
438 *
439 * If event_name is NULL, all events are disabled.
440 * If channel_name is NULL, the default channel is used (channel0).
441 */
442 extern int lttng_disable_event(struct lttng_handle *handle,
443 const char *name, const char *channel_name);
444
445 /*
446 * Disable channel.
447 *
448 * The channel name cannot be NULL.
449 */
450 extern int lttng_disable_channel(struct lttng_handle *handle,
451 const char *name);
452
453 /*
454 * Calibrate LTTng overhead.
455 */
456 extern int lttng_calibrate(struct lttng_handle *handle,
457 struct lttng_calibrate *calibrate);
458
459 /*
460 * Set the default channel attributes for a specific domain and an allocated
461 * lttng_channel_attr pointer.
462 *
463 * If either or both of the arguments are NULL, nothing happens.
464 */
465 extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
466 struct lttng_channel_attr *attr);
467
468 #endif /* _LTTNG_H */
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