lttng-sessiond: keep enabled/active state for sessions, cleanup enabled state for...
[lttng-tools.git] / include / lttng / lttng.h
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826d496d 1/*
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2 * lttng.h
3 *
4 * Linux Trace Toolkit Control Library Header File
5 *
826d496d 6 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
fac6795d 7 *
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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,
fac6795d 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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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
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21 */
22
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23#ifndef _LTTNG_H
24#define _LTTNG_H
fac6795d 25
57167058 26#include <limits.h>
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27#include <stdint.h>
28#include <sys/types.h>
57167058 29
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30/* Default unix group name for tracing. */
31#define LTTNG_DEFAULT_TRACING_GROUP "tracing"
fac6795d 32
b7384347 33/* Environment variable to set session daemon binary path. */
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34#define LTTNG_SESSIOND_PATH_ENV "LTTNG_SESSIOND_PATH"
35
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36/* Default trace output directory name */
37#define LTTNG_DEFAULT_TRACE_DIR_NAME "lttng-traces"
38
b7384347 39/*
e6ddca71 40 * Event symbol length. Copied from LTTng kernel ABI.
1657e9bb 41 */
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42#define LTTNG_SYMBOL_NAME_LEN 128
43
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44/*
45 * Every lttng_event_* structure both apply to kernel event and user-space
46 * event.
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47 */
48
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49/*
50 * Domain type are the different possible tracers.
51 */
52enum lttng_domain_type {
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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,
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58};
59
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60/*
61 * Instrumentation type of tracing event.
62 */
f3ed775e 63enum lttng_event_type {
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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,
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71};
72
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73/*
74 * LTTng consumer mode
75 */
76enum lttng_event_output {
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77 LTTNG_EVENT_SPLICE = 0,
78 LTTNG_EVENT_MMAP = 1,
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79};
80
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81/* Event context possible type */
82enum 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,
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93};
94
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95enum lttng_calibrate_type {
96 LTTNG_CALIBRATE_FUNCTION = 0,
97};
98
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99struct lttng_domain {
100 enum lttng_domain_type type;
101 union {
102 pid_t pid;
103 char exec_name[NAME_MAX];
104 } attr;
105};
106
d65106b1 107/* Perf counter attributes */
7d29a247 108struct lttng_event_perf_counter_ctx {
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109 uint32_t type;
110 uint64_t config;
111 char name[LTTNG_SYMBOL_NAME_LEN];
112};
113
114/* Event/Channel context */
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115struct lttng_event_context {
116 enum lttng_event_context_type ctx;
d65106b1 117 union {
7d29a247 118 struct lttng_event_perf_counter_ctx perf_counter;
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119 } u;
120};
121
b7384347 122/*
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123 * Event probe.
124 *
125 * Either addr is used or symbol_name and offset.
57167058 126 */
7d29a247 127struct lttng_event_probe_attr {
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128 uint64_t addr;
129
130 uint64_t offset;
131 char symbol_name[LTTNG_SYMBOL_NAME_LEN];
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132};
133
b7384347 134/*
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135 * Function tracer
136 */
137struct lttng_event_function_attr {
138 char symbol_name[LTTNG_SYMBOL_NAME_LEN];
139};
140
141/*
142 * Generic lttng event
143 */
144struct lttng_event {
145 char name[LTTNG_SYMBOL_NAME_LEN];
146 enum lttng_event_type type;
9f19cc17 147 uint32_t enabled;
b551a063 148 pid_t pid;
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149 /* Per event type configuration */
150 union {
7d29a247 151 struct lttng_event_probe_attr probe;
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152 struct lttng_event_function_attr ftrace;
153 } attr;
154};
155
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156/*
157 * Tracer channel attributes. For both kernel and user-space.
158 */
f3ed775e 159struct lttng_channel_attr {
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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 */
f05b5f07 165 enum lttng_event_output output; /* splice, mmap */
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166};
167
168/*
e6ddca71 169 * Channel information structure. For both kernel and user-space.
1657e9bb 170 */
e6ddca71 171struct lttng_channel {
1657e9bb 172 char name[NAME_MAX];
9f19cc17 173 uint32_t enabled;
e6ddca71 174 struct lttng_channel_attr attr;
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175};
176
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177struct lttng_calibrate {
178 enum lttng_calibrate_type type;
179};
180
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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 */
188struct lttng_session {
f3ed775e 189 char name[NAME_MAX];
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190 /* The path where traces are written */
191 char path[PATH_MAX];
464dd62d 192 uint32_t enabled; /* enabled/started: 1, disabled/stopped: 0 */
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193};
194
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195/*
196 * Handle used as a context for commands.
197 */
198struct lttng_handle {
199 char session_name[NAME_MAX];
200 struct lttng_domain domain;
201};
202
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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
9a745bc7 213 * code which can be humanly interpreted with lttng_strerror(err).
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214 */
215
b7384347 216/*
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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 */
222extern 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.
b7384347 228 */
cd80958d 229extern void lttng_destroy_handle(struct lttng_handle *handle);
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230
231/*
232 * Create tracing session using a name and a path where trace will be written.
233 */
38057ed1 234extern int lttng_create_session(const char *name, const char *path);
f3ed775e 235
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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 */
cd80958d 242extern int lttng_destroy_session(struct lttng_handle *handle);
f3ed775e 243
e6ddca71 244/*
9f19cc17 245 * List all tracing sessions.
7d29a247 246 *
9f19cc17 247 * Return the size of the "lttng_session" array. Caller must free(3).
e6ddca71 248 */
ca95a216 249extern int lttng_list_sessions(struct lttng_session **sessions);
f3ed775e 250
9f19cc17 251/*
2a71efd5 252 * List registered domain(s) of a session.
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253 *
254 * Return the size of the "lttng_domain" array. Caller must free(3).
255 */
cd80958d 256extern int lttng_list_domains(struct lttng_handle *handle,
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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 */
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264extern int lttng_list_channels(struct lttng_handle *handle,
265 struct lttng_channel **channels);
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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 */
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272extern int lttng_list_events(struct lttng_handle *handle,
273 const char *channel_name, struct lttng_event **events);
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274
275/*
cd80958d 276 * List available tracepoints of a specific lttng domain.
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277 *
278 * Return the size of the "lttng_event" array. Caller must free(3).
279 */
cd80958d 280extern int lttng_list_tracepoints(struct lttng_handle *handle,
2a71efd5 281 struct lttng_event **events);
9f19cc17 282
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283/*
284 * Check if a session daemon is alive.
285 */
947308c4 286extern int lttng_session_daemon_alive(void);
f3ed775e 287
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288/*
289 * Set tracing group for the *current* flow of execution.
290 */
b7384347 291extern int lttng_set_tracing_group(const char *name);
f3ed775e 292
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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 */
9a745bc7 298extern const char *lttng_strerror(int code);
b7384347 299
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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 *
3bd1e081 305 * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
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306 * command socket. The error socket is not supported yet for roaming consumers.
307 */
308extern int lttng_register_consumer(struct lttng_handle *handle,
309 const char *socket_path);
310
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311/*
312 * Start tracing for *all* registered trace (kernel and user-space).
313 */
cd80958d 314extern int lttng_start_tracing(struct lttng_handle *handle);
f3ed775e 315
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316/*
317 * Stop tracing for *all* registered trace (kernel and user-space).
318 */
cd80958d 319extern int lttng_stop_tracing(struct lttng_handle *handle);
f3ed775e 320
b7384347 321/*
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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.
b7384347 327 */
cd80958d 328extern int lttng_add_context(struct lttng_handle *handle,
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329 struct lttng_event_context *ctx, const char *event_name,
330 const char *channel_name);
f3ed775e 331
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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 */
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340extern int lttng_enable_event(struct lttng_handle *handle,
341 struct lttng_event *ev, const char *channel_name);
f3ed775e 342
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343/*
344 * Create or enable a kernel channel.
345 *
346 * If name is NULL, the default channel is enabled (channel0).
347 */
cd80958d 348extern int lttng_enable_channel(struct lttng_handle *handle,
38057ed1 349 struct lttng_channel *chan);
f3ed775e 350
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351/*
352 * Disable kernel event.
353 *
354 * If channel_name is NULL, the default channel is used (channel0).
355 */
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356extern int lttng_disable_event(struct lttng_handle *handle,
357 const char *name, const char *channel_name);
fac6795d 358
1df4dedd 359/*
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360 * Disable kernel channel.
361 *
362 * If channel_name is NULL, the default channel is disabled (channel0).
1df4dedd 363 */
cd80958d 364extern int lttng_disable_channel(struct lttng_handle *handle,
38057ed1 365 const char *name);
1df4dedd 366
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367/*
368 * Calibrate LTTng overhead.
369 */
cd80958d 370extern int lttng_calibrate(struct lttng_handle *handle,
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371 struct lttng_calibrate *calibrate);
372
b7384347 373#endif /* _LTTNG_H */
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