lttng-sessiond: keep enabled/active state for sessions, cleanup enabled state for...
[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 pid_t pid;
149 /* Per event type configuration */
150 union {
151 struct lttng_event_probe_attr probe;
152 struct lttng_event_function_attr ftrace;
153 } attr;
154 };
155
156 /*
157 * Tracer channel attributes. For both kernel and user-space.
158 */
159 struct lttng_channel_attr {
160 int overwrite; /* 1: overwrite, 0: discard */
161 uint64_t subbuf_size; /* bytes */
162 uint64_t num_subbuf; /* power of 2 */
163 unsigned int switch_timer_interval; /* usec */
164 unsigned int read_timer_interval; /* usec */
165 enum lttng_event_output output; /* splice, mmap */
166 };
167
168 /*
169 * Channel information structure. For both kernel and user-space.
170 */
171 struct lttng_channel {
172 char name[NAME_MAX];
173 uint32_t enabled;
174 struct lttng_channel_attr attr;
175 };
176
177 struct lttng_calibrate {
178 enum lttng_calibrate_type type;
179 };
180
181 /*
182 * Basic session information.
183 *
184 * This is an 'output data' meaning that it only comes *from* the session
185 * daemon *to* the lttng client. It's basically a 'human' representation of
186 * tracing entities (here a session).
187 */
188 struct lttng_session {
189 char name[NAME_MAX];
190 /* The path where traces are written */
191 char path[PATH_MAX];
192 uint32_t enabled; /* enabled/started: 1, disabled/stopped: 0 */
193 };
194
195 /*
196 * Handle used as a context for commands.
197 */
198 struct lttng_handle {
199 char session_name[NAME_MAX];
200 struct lttng_domain domain;
201 };
202
203 /*
204 * Public LTTng control API
205 *
206 * For functions having a lttng domain type as parameter, if a bad value is
207 * given, NO default is applied and an error is returned.
208 *
209 * On success, all functions of the API return 0 or the size of the allocated
210 * array.
211 *
212 * On error, a negative value is returned being a specific lttng-tools error
213 * code which can be humanly interpreted with lttng_strerror(err).
214 */
215
216 /*
217 * Create an handle used as a context for every request made to the library.
218 *
219 * This handle contains the session name and lttng domain on which the command
220 * will be executed on.
221 */
222 extern struct lttng_handle *lttng_create_handle(const char *session_name,
223 struct lttng_domain *domain);
224
225 /*
226 * Destroy an handle. This will simply free(3) the data pointer returned by
227 * lttng_create_handle() and rendering it unsuable.
228 */
229 extern void lttng_destroy_handle(struct lttng_handle *handle);
230
231 /*
232 * Create tracing session using a name and a path where trace will be written.
233 */
234 extern int lttng_create_session(const char *name, const char *path);
235
236 /*
237 * Destroy tracing session.
238 *
239 * The session will not be useable anymore, tracing will stopped for all
240 * registered trace and tracing buffers will be flushed.
241 */
242 extern int lttng_destroy_session(struct lttng_handle *handle);
243
244 /*
245 * List all tracing sessions.
246 *
247 * Return the size of the "lttng_session" array. Caller must free(3).
248 */
249 extern int lttng_list_sessions(struct lttng_session **sessions);
250
251 /*
252 * List registered domain(s) of a session.
253 *
254 * Return the size of the "lttng_domain" array. Caller must free(3).
255 */
256 extern int lttng_list_domains(struct lttng_handle *handle,
257 struct lttng_domain **domains);
258
259 /*
260 * List channel(s) of a session.
261 *
262 * Return the size of the "lttng_channel" array. Caller must free(3).
263 */
264 extern int lttng_list_channels(struct lttng_handle *handle,
265 struct lttng_channel **channels);
266
267 /*
268 * List event(s) of a session channel.
269 *
270 * Return the size of the "lttng_event" array. Caller must free(3).
271 */
272 extern int lttng_list_events(struct lttng_handle *handle,
273 const char *channel_name, struct lttng_event **events);
274
275 /*
276 * List available tracepoints of a specific lttng domain.
277 *
278 * Return the size of the "lttng_event" array. Caller must free(3).
279 */
280 extern int lttng_list_tracepoints(struct lttng_handle *handle,
281 struct lttng_event **events);
282
283 /*
284 * Check if a session daemon is alive.
285 */
286 extern int lttng_session_daemon_alive(void);
287
288 /*
289 * Set tracing group for the *current* flow of execution.
290 */
291 extern int lttng_set_tracing_group(const char *name);
292
293 /*
294 * Return a human readable error message of a lttng-tools error code.
295 *
296 * Parameter MUST be a negative value or else you'll get a generic message.
297 */
298 extern const char *lttng_strerror(int code);
299
300 /*
301 * This call permits to register an "outside consumer" to a session and a lttng
302 * domain. No consumer will be spawned and all fds/commands will go through the
303 * socket path given (socket_path).
304 *
305 * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
306 * command socket. The error socket is not supported yet for roaming consumers.
307 */
308 extern int lttng_register_consumer(struct lttng_handle *handle,
309 const char *socket_path);
310
311 /*
312 * Start tracing for *all* registered trace (kernel and user-space).
313 */
314 extern int lttng_start_tracing(struct lttng_handle *handle);
315
316 /*
317 * Stop tracing for *all* registered trace (kernel and user-space).
318 */
319 extern int lttng_stop_tracing(struct lttng_handle *handle);
320
321 /*
322 * Add context to event for a specific channel.
323 *
324 * If event_name is NULL, the context is applied to all event of the channel.
325 * If channel_name is NULL, a lookup of the event's channel is done.
326 * If both are NULL, the context is applied on all events of all channels.
327 */
328 extern int lttng_add_context(struct lttng_handle *handle,
329 struct lttng_event_context *ctx, const char *event_name,
330 const char *channel_name);
331
332 /*
333 * Create or enable a kernel event.
334 *
335 * If the event you are trying to enable does not exist, it will be created,
336 * else it is enabled.
337 *
338 * If channel_name is NULL, the default channel is used (channel0).
339 */
340 extern int lttng_enable_event(struct lttng_handle *handle,
341 struct lttng_event *ev, const char *channel_name);
342
343 /*
344 * Create or enable a kernel channel.
345 *
346 * If name is NULL, the default channel is enabled (channel0).
347 */
348 extern int lttng_enable_channel(struct lttng_handle *handle,
349 struct lttng_channel *chan);
350
351 /*
352 * Disable kernel event.
353 *
354 * If channel_name is NULL, the default channel is used (channel0).
355 */
356 extern int lttng_disable_event(struct lttng_handle *handle,
357 const char *name, const char *channel_name);
358
359 /*
360 * Disable kernel channel.
361 *
362 * If channel_name is NULL, the default channel is disabled (channel0).
363 */
364 extern int lttng_disable_channel(struct lttng_handle *handle,
365 const char *name);
366
367 /*
368 * Calibrate LTTng overhead.
369 */
370 extern int lttng_calibrate(struct lttng_handle *handle,
371 struct lttng_calibrate *calibrate);
372
373 #endif /* _LTTNG_H */
This page took 0.055469 seconds and 4 git commands to generate.