listing and activation of loglevel by number
[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 int64_t loglevel_value;
149 enum lttng_event_type type;
150 uint32_t enabled;
151 pid_t pid;
152 /* Per event type configuration */
153 union {
154 struct lttng_event_probe_attr probe;
155 struct lttng_event_function_attr ftrace;
156 } attr;
157 };
158
159 /*
160 * Tracer channel attributes. For both kernel and user-space.
161 */
162 struct lttng_channel_attr {
163 int overwrite; /* 1: overwrite, 0: discard */
164 uint64_t subbuf_size; /* bytes */
165 uint64_t num_subbuf; /* power of 2 */
166 unsigned int switch_timer_interval; /* usec */
167 unsigned int read_timer_interval; /* usec */
168 enum lttng_event_output output; /* splice, mmap */
169 };
170
171 /*
172 * Channel information structure. For both kernel and user-space.
173 */
174 struct lttng_channel {
175 char name[NAME_MAX];
176 uint32_t enabled;
177 struct lttng_channel_attr attr;
178 };
179
180 struct lttng_calibrate {
181 enum lttng_calibrate_type type;
182 };
183
184 /*
185 * Basic session information.
186 *
187 * This is an 'output data' meaning that it only comes *from* the session
188 * daemon *to* the lttng client. It's basically a 'human' representation of
189 * tracing entities (here a session).
190 */
191 struct lttng_session {
192 char name[NAME_MAX];
193 /* The path where traces are written */
194 char path[PATH_MAX];
195 uint32_t enabled; /* enabled/started: 1, disabled/stopped: 0 */
196 };
197
198 /*
199 * Handle used as a context for commands.
200 */
201 struct lttng_handle {
202 char session_name[NAME_MAX];
203 struct lttng_domain domain;
204 };
205
206 /*
207 * Public LTTng control API
208 *
209 * For functions having a lttng domain type as parameter, if a bad value is
210 * given, NO default is applied and an error is returned.
211 *
212 * On success, all functions of the API return 0 or the size of the allocated
213 * array.
214 *
215 * On error, a negative value is returned being a specific lttng-tools error
216 * code which can be humanly interpreted with lttng_strerror(err).
217 */
218
219 /*
220 * Create an handle used as a context for every request made to the library.
221 *
222 * This handle contains the session name and lttng domain on which the command
223 * will be executed on.
224 */
225 extern struct lttng_handle *lttng_create_handle(const char *session_name,
226 struct lttng_domain *domain);
227
228 /*
229 * Destroy an handle. This will simply free(3) the data pointer returned by
230 * lttng_create_handle() and rendering it unsuable.
231 */
232 extern void lttng_destroy_handle(struct lttng_handle *handle);
233
234 /*
235 * Create tracing session using a name and a path where trace will be written.
236 */
237 extern int lttng_create_session(const char *name, const char *path);
238
239 /*
240 * Destroy tracing session.
241 *
242 * The session will not be useable anymore, tracing will stopped for all
243 * registered trace and tracing buffers will be flushed.
244 */
245 extern int lttng_destroy_session(struct lttng_handle *handle);
246
247 /*
248 * List all tracing sessions.
249 *
250 * Return the size of the "lttng_session" array. Caller must free(3).
251 */
252 extern int lttng_list_sessions(struct lttng_session **sessions);
253
254 /*
255 * List registered domain(s) of a session.
256 *
257 * Return the size of the "lttng_domain" array. Caller must free(3).
258 */
259 extern int lttng_list_domains(struct lttng_handle *handle,
260 struct lttng_domain **domains);
261
262 /*
263 * List channel(s) of a session.
264 *
265 * Return the size of the "lttng_channel" array. Caller must free(3).
266 */
267 extern int lttng_list_channels(struct lttng_handle *handle,
268 struct lttng_channel **channels);
269
270 /*
271 * List event(s) of a session channel.
272 *
273 * Return the size of the "lttng_event" array. Caller must free(3).
274 */
275 extern int lttng_list_events(struct lttng_handle *handle,
276 const char *channel_name, struct lttng_event **events);
277
278 /*
279 * List available tracepoints of a specific lttng domain.
280 *
281 * Return the size of the "lttng_event" array. Caller must free(3).
282 */
283 extern int lttng_list_tracepoints(struct lttng_handle *handle,
284 struct lttng_event **events);
285
286 /*
287 * Check if a session daemon is alive.
288 */
289 extern int lttng_session_daemon_alive(void);
290
291 /*
292 * Set tracing group for the *current* flow of execution.
293 */
294 extern int lttng_set_tracing_group(const char *name);
295
296 /*
297 * Return a human readable error message of a lttng-tools error code.
298 *
299 * Parameter MUST be a negative value or else you'll get a generic message.
300 */
301 extern const char *lttng_strerror(int code);
302
303 /*
304 * This call permits to register an "outside consumer" to a session and a lttng
305 * domain. No consumer will be spawned and all fds/commands will go through the
306 * socket path given (socket_path).
307 *
308 * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
309 * command socket. The error socket is not supported yet for roaming consumers.
310 */
311 extern int lttng_register_consumer(struct lttng_handle *handle,
312 const char *socket_path);
313
314 /*
315 * Start tracing for *all* registered trace (kernel and user-space).
316 */
317 extern int lttng_start_tracing(struct lttng_handle *handle);
318
319 /*
320 * Stop tracing for *all* registered trace (kernel and user-space).
321 */
322 extern int lttng_stop_tracing(struct lttng_handle *handle);
323
324 /*
325 * Add context to event for a specific channel.
326 *
327 * If event_name is NULL, the context is applied to all event of the channel.
328 * If channel_name is NULL, a lookup of the event's channel is done.
329 * If both are NULL, the context is applied on all events of all channels.
330 */
331 extern int lttng_add_context(struct lttng_handle *handle,
332 struct lttng_event_context *ctx, const char *event_name,
333 const char *channel_name);
334
335 /*
336 * Create or enable a kernel event.
337 *
338 * If the event you are trying to enable does not exist, it will be created,
339 * else it is enabled.
340 *
341 * If channel_name is NULL, the default channel is used (channel0).
342 */
343 extern int lttng_enable_event(struct lttng_handle *handle,
344 struct lttng_event *ev, const char *channel_name);
345
346 /*
347 * Create or enable a kernel channel.
348 *
349 * If name is NULL, the default channel is enabled (channel0).
350 */
351 extern int lttng_enable_channel(struct lttng_handle *handle,
352 struct lttng_channel *chan);
353
354 /*
355 * Disable kernel event.
356 *
357 * If channel_name is NULL, the default channel is used (channel0).
358 */
359 extern int lttng_disable_event(struct lttng_handle *handle,
360 const char *name, const char *channel_name);
361
362 /*
363 * Disable kernel channel.
364 *
365 * If channel_name is NULL, the default channel is disabled (channel0).
366 */
367 extern int lttng_disable_channel(struct lttng_handle *handle,
368 const char *name);
369
370 /*
371 * Calibrate LTTng overhead.
372 */
373 extern int lttng_calibrate(struct lttng_handle *handle,
374 struct lttng_calibrate *calibrate);
375
376 /*
377 * Set the default channel attributes for a specific domain and an allocated
378 * lttng_channel_attr pointer.
379 */
380 extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
381 struct lttng_channel_attr *attr);
382
383 #endif /* _LTTNG_H */
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