API change for lttng_get_readeable_code
[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 128
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 };
72
73 /*
74 * LTTng consumer mode
75 */
76 enum lttng_event_output {
77 LTTNG_EVENT_SPLICE = 0,
78 LTTNG_EVENT_MMAP = 1,
79 };
80
81 /* Event context possible type */
82 enum lttng_event_context_type {
83 LTTNG_EVENT_CONTEXT_PID = 0,
84 LTTNG_EVENT_CONTEXT_PERF_COUNTER = 1,
85 LTTNG_EVENT_CONTEXT_COMM = 2,
86 LTTNG_EVENT_CONTEXT_PRIO = 3,
87 LTTNG_EVENT_CONTEXT_NICE = 4,
88 LTTNG_EVENT_CONTEXT_VPID = 5,
89 LTTNG_EVENT_CONTEXT_TID = 6,
90 LTTNG_EVENT_CONTEXT_VTID = 7,
91 LTTNG_EVENT_CONTEXT_PPID = 8,
92 LTTNG_EVENT_CONTEXT_VPPID = 9,
93 };
94
95 enum lttng_calibrate_type {
96 LTTNG_CALIBRATE_FUNCTION = 0,
97 };
98
99 struct lttng_domain {
100 enum lttng_domain_type type;
101 union {
102 pid_t pid;
103 char exec_name[NAME_MAX];
104 } attr;
105 };
106
107 /* Perf counter attributes */
108 struct lttng_event_perf_counter_ctx {
109 uint32_t type;
110 uint64_t config;
111 char name[LTTNG_SYMBOL_NAME_LEN];
112 };
113
114 /* Event/Channel context */
115 struct lttng_event_context {
116 enum lttng_event_context_type ctx;
117 union {
118 struct lttng_event_perf_counter_ctx perf_counter;
119 } u;
120 };
121
122 /*
123 * Event probe.
124 *
125 * Either addr is used or symbol_name and offset.
126 */
127 struct lttng_event_probe_attr {
128 uint64_t addr;
129
130 uint64_t offset;
131 char symbol_name[LTTNG_SYMBOL_NAME_LEN];
132 };
133
134 /*
135 * Function tracer
136 */
137 struct lttng_event_function_attr {
138 char symbol_name[LTTNG_SYMBOL_NAME_LEN];
139 };
140
141 /*
142 * Generic lttng event
143 */
144 struct lttng_event {
145 char name[LTTNG_SYMBOL_NAME_LEN];
146 enum lttng_event_type type;
147 uint32_t enabled;
148 /* Per event type configuration */
149 union {
150 struct lttng_event_probe_attr probe;
151 struct lttng_event_function_attr ftrace;
152 } attr;
153 };
154
155 /*
156 * Tracer channel attributes. For both kernel and user-space.
157 */
158 struct lttng_channel_attr {
159 int overwrite; /* 1: overwrite, 0: discard */
160 uint64_t subbuf_size; /* bytes */
161 uint64_t num_subbuf; /* power of 2 */
162 unsigned int switch_timer_interval; /* usec */
163 unsigned int read_timer_interval; /* usec */
164 enum lttng_event_output output; /* splice, mmap */
165 };
166
167 /*
168 * Channel information structure. For both kernel and user-space.
169 */
170 struct lttng_channel {
171 char name[NAME_MAX];
172 uint32_t enabled;
173 struct lttng_channel_attr attr;
174 };
175
176 struct lttng_calibrate {
177 enum lttng_calibrate_type type;
178 };
179
180 /*
181 * Basic session information.
182 *
183 * This is an 'output data' meaning that it only comes *from* the session
184 * daemon *to* the lttng client. It's basically a 'human' representation of
185 * tracing entities (here a session).
186 */
187 struct lttng_session {
188 char name[NAME_MAX];
189 /* The path where traces are written */
190 char path[PATH_MAX];
191 };
192
193 /*
194 * Handle used as a context for commands.
195 */
196 struct lttng_handle {
197 char session_name[NAME_MAX];
198 struct lttng_domain domain;
199 };
200
201 /*
202 * Public LTTng control API
203 *
204 * For functions having a lttng domain type as parameter, if a bad value is
205 * given, NO default is applied and an error is returned.
206 *
207 * On success, all functions of the API return 0 or the size of the allocated
208 * array.
209 *
210 * On error, a negative value is returned being a specific lttng-tools error
211 * code which can be humanly interpreted with lttng_strerror(err).
212 */
213
214 /*
215 * Create an handle used as a context for every request made to the library.
216 *
217 * This handle contains the session name and lttng domain on which the command
218 * will be executed on.
219 */
220 extern struct lttng_handle *lttng_create_handle(const char *session_name,
221 struct lttng_domain *domain);
222
223 /*
224 * Destroy an handle. This will simply free(3) the data pointer returned by
225 * lttng_create_handle() and rendering it unsuable.
226 */
227 extern void lttng_destroy_handle(struct lttng_handle *handle);
228
229 /*
230 * Create tracing session using a name and a path where trace will be written.
231 */
232 extern int lttng_create_session(const char *name, const char *path);
233
234 /*
235 * Destroy tracing session.
236 *
237 * The session will not be useable anymore, tracing will stopped for all
238 * registered trace and tracing buffers will be flushed.
239 */
240 extern int lttng_destroy_session(struct lttng_handle *handle);
241
242 /*
243 * List all tracing sessions.
244 *
245 * Return the size of the "lttng_session" array. Caller must free(3).
246 */
247 extern int lttng_list_sessions(struct lttng_session **sessions);
248
249 /*
250 * List registered domain(s) of a session.
251 *
252 * Return the size of the "lttng_domain" array. Caller must free(3).
253 */
254 extern int lttng_list_domains(struct lttng_handle *handle,
255 struct lttng_domain **domains);
256
257 /*
258 * List channel(s) of a session.
259 *
260 * Return the size of the "lttng_channel" array. Caller must free(3).
261 */
262 extern int lttng_list_channels(struct lttng_handle *handle,
263 struct lttng_channel **channels);
264
265 /*
266 * List event(s) of a session channel.
267 *
268 * Return the size of the "lttng_event" array. Caller must free(3).
269 */
270 extern int lttng_list_events(struct lttng_handle *handle,
271 const char *channel_name, struct lttng_event **events);
272
273 /*
274 * List available tracepoints of a specific lttng domain.
275 *
276 * Return the size of the "lttng_event" array. Caller must free(3).
277 */
278 extern int lttng_list_tracepoints(struct lttng_handle *handle,
279 struct lttng_event **events);
280
281 /*
282 * Check if a session daemon is alive.
283 */
284 extern int lttng_session_daemon_alive(void);
285
286 /*
287 * Set tracing group for the *current* flow of execution.
288 */
289 extern int lttng_set_tracing_group(const char *name);
290
291 /*
292 * Return a human readable error message of a lttng-tools error code.
293 *
294 * Parameter MUST be a negative value or else you'll get a generic message.
295 */
296 extern const char *lttng_strerror(int code);
297
298 /*
299 * This call permits to register an "outside consumer" to a session and a lttng
300 * domain. No consumer will be spawned and all fds/commands will go through the
301 * socket path given (socket_path).
302 *
303 * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
304 * command socket. The error socket is not supported yet for roaming consumers.
305 */
306 extern int lttng_register_consumer(struct lttng_handle *handle,
307 const char *socket_path);
308
309 /*
310 * Start tracing for *all* registered trace (kernel and user-space).
311 */
312 extern int lttng_start_tracing(struct lttng_handle *handle);
313
314 /*
315 * Stop tracing for *all* registered trace (kernel and user-space).
316 */
317 extern int lttng_stop_tracing(struct lttng_handle *handle);
318
319 /*
320 * Add context to event for a specific channel.
321 *
322 * If event_name is NULL, the context is applied to all event of the channel.
323 * If channel_name is NULL, a lookup of the event's channel is done.
324 * If both are NULL, the context is applied on all events of all channels.
325 */
326 extern int lttng_add_context(struct lttng_handle *handle,
327 struct lttng_event_context *ctx, const char *event_name,
328 const char *channel_name);
329
330 /*
331 * Create or enable a kernel event.
332 *
333 * If the event you are trying to enable does not exist, it will be created,
334 * else it is enabled.
335 *
336 * If channel_name is NULL, the default channel is used (channel0).
337 */
338 extern int lttng_enable_event(struct lttng_handle *handle,
339 struct lttng_event *ev, const char *channel_name);
340
341 /*
342 * Create or enable a kernel channel.
343 *
344 * If name is NULL, the default channel is enabled (channel0).
345 */
346 extern int lttng_enable_channel(struct lttng_handle *handle,
347 struct lttng_channel *chan);
348
349 /*
350 * Disable kernel event.
351 *
352 * If channel_name is NULL, the default channel is used (channel0).
353 */
354 extern int lttng_disable_event(struct lttng_handle *handle,
355 const char *name, const char *channel_name);
356
357 /*
358 * Disable kernel channel.
359 *
360 * If channel_name is NULL, the default channel is disabled (channel0).
361 */
362 extern int lttng_disable_channel(struct lttng_handle *handle,
363 const char *name);
364
365 /*
366 * Calibrate LTTng overhead.
367 */
368 extern int lttng_calibrate(struct lttng_handle *handle,
369 struct lttng_calibrate *calibrate);
370
371 #endif /* _LTTNG_H */
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