3dd915f61a6f10716df834072b35767e04e87d9b
[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
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; only
11 * version 2.1 of the License.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #ifndef _LTTNG_H
24 #define _LTTNG_H
25
26 #include <limits.h>
27 #include <stdint.h>
28 #include <sys/types.h>
29
30 /* Default unix group name for tracing. */
31 #define LTTNG_DEFAULT_TRACING_GROUP "tracing"
32
33 /* Environment variable to set session daemon binary path. */
34 #define LTTNG_SESSIOND_PATH_ENV "LTTNG_SESSIOND_PATH"
35
36 /* Default trace output directory name */
37 #define LTTNG_DEFAULT_TRACE_DIR_NAME "lttng-traces"
38
39 /*
40 * Event symbol length. Copied from LTTng kernel ABI.
41 */
42 #define LTTNG_SYMBOL_NAME_LEN 256
43
44 /*
45 * Every lttng_event_* structure both apply to kernel event and user-space
46 * event.
47 */
48
49 /*
50 * Domain type are the different possible tracers.
51 */
52 enum lttng_domain_type {
53 LTTNG_DOMAIN_KERNEL = 1,
54 LTTNG_DOMAIN_UST = 2,
55 LTTNG_DOMAIN_UST_EXEC_NAME = 3,
56 LTTNG_DOMAIN_UST_PID = 4,
57 LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN = 5,
58 };
59
60 /*
61 * Instrumentation type of tracing event.
62 */
63 enum lttng_event_type {
64 LTTNG_EVENT_ALL = -1,
65 LTTNG_EVENT_TRACEPOINT = 0,
66 LTTNG_EVENT_PROBE = 1,
67 LTTNG_EVENT_FUNCTION = 2,
68 LTTNG_EVENT_FUNCTION_ENTRY = 3,
69 LTTNG_EVENT_NOOP = 4,
70 LTTNG_EVENT_SYSCALL = 5,
71 LTTNG_EVENT_TRACEPOINT_LOGLEVEL = 6,
72 };
73
74 /*
75 * LTTng consumer mode
76 */
77 enum lttng_event_output {
78 LTTNG_EVENT_SPLICE = 0,
79 LTTNG_EVENT_MMAP = 1,
80 };
81
82 /* Event context possible type */
83 enum lttng_event_context_type {
84 LTTNG_EVENT_CONTEXT_PID = 0,
85 LTTNG_EVENT_CONTEXT_PERF_COUNTER = 1,
86 LTTNG_EVENT_CONTEXT_COMM = 2,
87 LTTNG_EVENT_CONTEXT_PRIO = 3,
88 LTTNG_EVENT_CONTEXT_NICE = 4,
89 LTTNG_EVENT_CONTEXT_VPID = 5,
90 LTTNG_EVENT_CONTEXT_TID = 6,
91 LTTNG_EVENT_CONTEXT_VTID = 7,
92 LTTNG_EVENT_CONTEXT_PPID = 8,
93 LTTNG_EVENT_CONTEXT_VPPID = 9,
94 };
95
96 enum lttng_calibrate_type {
97 LTTNG_CALIBRATE_FUNCTION = 0,
98 };
99
100 struct lttng_domain {
101 enum lttng_domain_type type;
102 union {
103 pid_t pid;
104 char exec_name[NAME_MAX];
105 } attr;
106 };
107
108 /* Perf counter attributes */
109 struct lttng_event_perf_counter_ctx {
110 uint32_t type;
111 uint64_t config;
112 char name[LTTNG_SYMBOL_NAME_LEN];
113 };
114
115 /* Event/Channel context */
116 struct lttng_event_context {
117 enum lttng_event_context_type ctx;
118 union {
119 struct lttng_event_perf_counter_ctx perf_counter;
120 } u;
121 };
122
123 /*
124 * Event probe.
125 *
126 * Either addr is used or symbol_name and offset.
127 */
128 struct lttng_event_probe_attr {
129 uint64_t addr;
130
131 uint64_t offset;
132 char symbol_name[LTTNG_SYMBOL_NAME_LEN];
133 };
134
135 /*
136 * Function tracer
137 */
138 struct lttng_event_function_attr {
139 char symbol_name[LTTNG_SYMBOL_NAME_LEN];
140 };
141
142 /*
143 * Generic lttng event
144 */
145 struct lttng_event {
146 char name[LTTNG_SYMBOL_NAME_LEN];
147 char loglevel[LTTNG_SYMBOL_NAME_LEN];
148 enum lttng_event_type type;
149 uint32_t enabled;
150 pid_t pid;
151 /* Per event type configuration */
152 union {
153 struct lttng_event_probe_attr probe;
154 struct lttng_event_function_attr ftrace;
155 } attr;
156 };
157
158 /*
159 * Tracer channel attributes. For both kernel and user-space.
160 */
161 struct lttng_channel_attr {
162 int overwrite; /* 1: overwrite, 0: discard */
163 uint64_t subbuf_size; /* bytes */
164 uint64_t num_subbuf; /* power of 2 */
165 unsigned int switch_timer_interval; /* usec */
166 unsigned int read_timer_interval; /* usec */
167 enum lttng_event_output output; /* splice, mmap */
168 };
169
170 /*
171 * Channel information structure. For both kernel and user-space.
172 */
173 struct lttng_channel {
174 char name[NAME_MAX];
175 uint32_t enabled;
176 struct lttng_channel_attr attr;
177 };
178
179 struct lttng_calibrate {
180 enum lttng_calibrate_type type;
181 };
182
183 /*
184 * Basic session information.
185 *
186 * This is an 'output data' meaning that it only comes *from* the session
187 * daemon *to* the lttng client. It's basically a 'human' representation of
188 * tracing entities (here a session).
189 */
190 struct lttng_session {
191 char name[NAME_MAX];
192 /* The path where traces are written */
193 char path[PATH_MAX];
194 uint32_t enabled; /* enabled/started: 1, disabled/stopped: 0 */
195 };
196
197 /*
198 * Handle used as a context for commands.
199 */
200 struct lttng_handle {
201 char session_name[NAME_MAX];
202 struct lttng_domain domain;
203 };
204
205 /*
206 * Public LTTng control API
207 *
208 * For functions having a lttng domain type as parameter, if a bad value is
209 * given, NO default is applied and an error is returned.
210 *
211 * On success, all functions of the API return 0 or the size of the allocated
212 * array.
213 *
214 * On error, a negative value is returned being a specific lttng-tools error
215 * code which can be humanly interpreted with lttng_strerror(err).
216 */
217
218 /*
219 * Create an handle used as a context for every request made to the library.
220 *
221 * This handle contains the session name and lttng domain on which the command
222 * will be executed on.
223 */
224 extern struct lttng_handle *lttng_create_handle(const char *session_name,
225 struct lttng_domain *domain);
226
227 /*
228 * Destroy an handle. This will simply free(3) the data pointer returned by
229 * lttng_create_handle() and rendering it unsuable.
230 */
231 extern void lttng_destroy_handle(struct lttng_handle *handle);
232
233 /*
234 * Create tracing session using a name and a path where trace will be written.
235 */
236 extern int lttng_create_session(const char *name, const char *path);
237
238 /*
239 * Destroy tracing session.
240 *
241 * The session will not be useable anymore, tracing will stopped for all
242 * registered trace and tracing buffers will be flushed.
243 */
244 extern int lttng_destroy_session(struct lttng_handle *handle);
245
246 /*
247 * List all tracing sessions.
248 *
249 * Return the size of the "lttng_session" array. Caller must free(3).
250 */
251 extern int lttng_list_sessions(struct lttng_session **sessions);
252
253 /*
254 * List registered domain(s) of a session.
255 *
256 * Return the size of the "lttng_domain" array. Caller must free(3).
257 */
258 extern int lttng_list_domains(struct lttng_handle *handle,
259 struct lttng_domain **domains);
260
261 /*
262 * List channel(s) of a session.
263 *
264 * Return the size of the "lttng_channel" array. Caller must free(3).
265 */
266 extern int lttng_list_channels(struct lttng_handle *handle,
267 struct lttng_channel **channels);
268
269 /*
270 * List event(s) of a session channel.
271 *
272 * Return the size of the "lttng_event" array. Caller must free(3).
273 */
274 extern int lttng_list_events(struct lttng_handle *handle,
275 const char *channel_name, struct lttng_event **events);
276
277 /*
278 * List available tracepoints of a specific lttng domain.
279 *
280 * Return the size of the "lttng_event" array. Caller must free(3).
281 */
282 extern int lttng_list_tracepoints(struct lttng_handle *handle,
283 struct lttng_event **events);
284
285 /*
286 * Check if a session daemon is alive.
287 */
288 extern int lttng_session_daemon_alive(void);
289
290 /*
291 * Set tracing group for the *current* flow of execution.
292 */
293 extern int lttng_set_tracing_group(const char *name);
294
295 /*
296 * Return a human readable error message of a lttng-tools error code.
297 *
298 * Parameter MUST be a negative value or else you'll get a generic message.
299 */
300 extern const char *lttng_strerror(int code);
301
302 /*
303 * This call permits to register an "outside consumer" to a session and a lttng
304 * domain. No consumer will be spawned and all fds/commands will go through the
305 * socket path given (socket_path).
306 *
307 * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
308 * command socket. The error socket is not supported yet for roaming consumers.
309 */
310 extern int lttng_register_consumer(struct lttng_handle *handle,
311 const char *socket_path);
312
313 /*
314 * Start tracing for *all* registered trace (kernel and user-space).
315 */
316 extern int lttng_start_tracing(struct lttng_handle *handle);
317
318 /*
319 * Stop tracing for *all* registered trace (kernel and user-space).
320 */
321 extern int lttng_stop_tracing(struct lttng_handle *handle);
322
323 /*
324 * Add context to event for a specific channel.
325 *
326 * If event_name is NULL, the context is applied to all event of the channel.
327 * If channel_name is NULL, a lookup of the event's channel is done.
328 * If both are NULL, the context is applied on all events of all channels.
329 */
330 extern int lttng_add_context(struct lttng_handle *handle,
331 struct lttng_event_context *ctx, const char *event_name,
332 const char *channel_name);
333
334 /*
335 * Create or enable a kernel event.
336 *
337 * If the event you are trying to enable does not exist, it will be created,
338 * else it is enabled.
339 *
340 * If channel_name is NULL, the default channel is used (channel0).
341 */
342 extern int lttng_enable_event(struct lttng_handle *handle,
343 struct lttng_event *ev, const char *channel_name);
344
345 /*
346 * Create or enable a kernel channel.
347 *
348 * If name is NULL, the default channel is enabled (channel0).
349 */
350 extern int lttng_enable_channel(struct lttng_handle *handle,
351 struct lttng_channel *chan);
352
353 /*
354 * Disable kernel event.
355 *
356 * If channel_name is NULL, the default channel is used (channel0).
357 */
358 extern int lttng_disable_event(struct lttng_handle *handle,
359 const char *name, const char *channel_name);
360
361 /*
362 * Disable kernel channel.
363 *
364 * If channel_name is NULL, the default channel is disabled (channel0).
365 */
366 extern int lttng_disable_channel(struct lttng_handle *handle,
367 const char *name);
368
369 /*
370 * Calibrate LTTng overhead.
371 */
372 extern int lttng_calibrate(struct lttng_handle *handle,
373 struct lttng_calibrate *calibrate);
374
375 /*
376 * Set the default channel attributes for a specific domain and an allocated
377 * lttng_channel_attr pointer.
378 */
379 extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
380 struct lttng_channel_attr *attr);
381
382 #endif /* _LTTNG_H */
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