4 * Linux Trace Toolkit Control Library Header File
6 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
8 * This library is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU Lesser General Public License as published by the
10 * Free Software Foundation; only version 2.1 of the License.
12 * This library is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
17 * You should have received a copy of the GNU Lesser General Public License
18 * along with this library; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27 #include <sys/types.h>
30 * Event symbol length. Copied from LTTng kernel ABI.
32 #define LTTNG_SYMBOL_NAME_LEN 256
35 * Every lttng_event_* structure both apply to kernel event and user-space
40 * Domain types: the different possible tracers.
42 enum lttng_domain_type
{
43 LTTNG_DOMAIN_KERNEL
= 1,
47 * For now, the domains below are not implemented. However, we keep them
48 * here in order to retain their enum values for future development. Note
49 * that it is on the roadmap to implement them.
51 LTTNG_DOMAIN_UST_EXEC_NAME = 3,
52 LTTNG_DOMAIN_UST_PID = 4,
53 LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN = 5,
58 * Instrumentation type of tracing event.
60 enum lttng_event_type
{
62 LTTNG_EVENT_TRACEPOINT
= 0,
63 LTTNG_EVENT_PROBE
= 1,
64 LTTNG_EVENT_FUNCTION
= 2,
65 LTTNG_EVENT_FUNCTION_ENTRY
= 3,
67 LTTNG_EVENT_SYSCALL
= 5,
68 LTTNG_EVENT_TRACEPOINT_LOGLEVEL
= 6,
74 enum lttng_event_output
{
75 LTTNG_EVENT_SPLICE
= 0,
79 /* Event context possible type */
80 enum lttng_event_context_type
{
81 LTTNG_EVENT_CONTEXT_PID
= 0,
82 LTTNG_EVENT_CONTEXT_PERF_COUNTER
= 1,
83 LTTNG_EVENT_CONTEXT_PROCNAME
= 2,
84 LTTNG_EVENT_CONTEXT_PRIO
= 3,
85 LTTNG_EVENT_CONTEXT_NICE
= 4,
86 LTTNG_EVENT_CONTEXT_VPID
= 5,
87 LTTNG_EVENT_CONTEXT_TID
= 6,
88 LTTNG_EVENT_CONTEXT_VTID
= 7,
89 LTTNG_EVENT_CONTEXT_PPID
= 8,
90 LTTNG_EVENT_CONTEXT_VPPID
= 9,
91 LTTNG_EVENT_CONTEXT_PTHREAD_ID
= 10,
94 enum lttng_calibrate_type
{
95 LTTNG_CALIBRATE_FUNCTION
= 0,
99 enum lttng_domain_type type
;
102 char exec_name
[NAME_MAX
];
106 /* Perf counter attributes */
107 struct lttng_event_perf_counter_ctx
{
110 char name
[LTTNG_SYMBOL_NAME_LEN
];
113 /* Event/Channel context */
114 struct lttng_event_context
{
115 enum lttng_event_context_type ctx
;
117 struct lttng_event_perf_counter_ctx perf_counter
;
124 * Either addr is used or symbol_name and offset.
126 struct lttng_event_probe_attr
{
130 char symbol_name
[LTTNG_SYMBOL_NAME_LEN
];
136 struct lttng_event_function_attr
{
137 char symbol_name
[LTTNG_SYMBOL_NAME_LEN
];
141 * Generic lttng event
144 char name
[LTTNG_SYMBOL_NAME_LEN
];
145 char loglevel
[LTTNG_SYMBOL_NAME_LEN
];
146 int64_t loglevel_value
;
147 enum lttng_event_type type
;
150 /* Per event type configuration */
152 struct lttng_event_probe_attr probe
;
153 struct lttng_event_function_attr ftrace
;
158 * Tracer channel attributes. For both kernel and user-space.
160 struct lttng_channel_attr
{
161 int overwrite
; /* 1: overwrite, 0: discard */
162 uint64_t subbuf_size
; /* bytes */
163 uint64_t num_subbuf
; /* power of 2 */
164 unsigned int switch_timer_interval
; /* usec */
165 unsigned int read_timer_interval
; /* usec */
166 enum lttng_event_output output
; /* splice, mmap */
170 * Channel information structure. For both kernel and user-space.
172 struct lttng_channel
{
173 char name
[LTTNG_SYMBOL_NAME_LEN
];
175 struct lttng_channel_attr attr
;
178 struct lttng_calibrate
{
179 enum lttng_calibrate_type type
;
183 * Basic session information.
185 * This is an 'output data' meaning that it only comes *from* the session
186 * daemon *to* the lttng client. It's basically a 'human' representation of
187 * tracing entities (here a session).
189 struct lttng_session
{
191 /* The path where traces are written */
193 uint32_t enabled
; /* enabled/started: 1, disabled/stopped: 0 */
197 * Handle used as a context for commands.
199 struct lttng_handle
{
200 char session_name
[NAME_MAX
];
201 struct lttng_domain domain
;
205 * Public LTTng control API
207 * For functions having an lttng domain type as parameter, if a bad value is
208 * given, NO default is applied and an error is returned.
210 * On success, all functions of the API return 0 or the size of the allocated
213 * On error, a negative value is returned being a specific lttng-tools error
214 * code which can be humanly interpreted with lttng_strerror(err).
216 * Exceptions to this are noted below.
220 * Create a handle used as a context for every request made to the library.
222 * This handle contains the session name and lttng domain on which the command
224 * The returned pointer will be NULL in case of malloc() error.
226 extern struct lttng_handle
*lttng_create_handle(const char *session_name
,
227 struct lttng_domain
*domain
);
230 * Destroy a handle. This will simply free(3) the data pointer returned by
231 * lttng_create_handle(), rendering it unusable.
233 extern void lttng_destroy_handle(struct lttng_handle
*handle
);
236 * Create a tracing session using a name and a path where the trace will be
239 extern int lttng_create_session(const char *name
, const char *path
);
242 * Destroy a tracing session.
244 * The session will not be usable anymore, tracing will be stopped for all
245 * registered traces, and the tracing buffers will be flushed.
247 extern int lttng_destroy_session(const char *name
);
250 * List all the tracing sessions.
252 * Return the size (number of entries) of the "lttng_session" array. Caller
255 extern int lttng_list_sessions(struct lttng_session
**sessions
);
258 * List the registered domain(s) of a session.
260 * Return the size (number of entries) of the "lttng_domain" array. Caller
263 extern int lttng_list_domains(const char *session_name
,
264 struct lttng_domain
**domains
);
267 * List the channel(s) of a session.
269 * Return the size (number of entries) of the "lttng_channel" array. Caller
272 extern int lttng_list_channels(struct lttng_handle
*handle
,
273 struct lttng_channel
**channels
);
276 * List the event(s) of a session channel.
278 * Return the size (number of entries) of the "lttng_event" array.
279 * Caller must free(3).
281 extern int lttng_list_events(struct lttng_handle
*handle
,
282 const char *channel_name
, struct lttng_event
**events
);
285 * List the available tracepoints of a specific lttng domain.
287 * Return the size (number of entries) of the "lttng_event" array.
288 * Caller must free(3).
290 extern int lttng_list_tracepoints(struct lttng_handle
*handle
,
291 struct lttng_event
**events
);
294 * Check if a session daemon is alive.
296 * Return 1 if alive or 0 if not. On error returns a negative value.
298 extern int lttng_session_daemon_alive(void);
301 * Set the tracing group for the *current* flow of execution.
303 * On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
305 extern int lttng_set_tracing_group(const char *name
);
308 * Return a human-readable error message for an lttng-tools error code.
310 * Parameter MUST be a negative value or else you'll get a generic message.
312 extern const char *lttng_strerror(int code
);
315 * This call registers an "outside consumer" for a session and an lttng domain.
316 * No consumer will be spawned and all fds/commands will go through the socket
317 * path given (socket_path).
319 * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
320 * command socket. The error socket is not supported yet for roaming consumers.
322 extern int lttng_register_consumer(struct lttng_handle
*handle
,
323 const char *socket_path
);
326 * Start tracing for *all* registered traces (kernel and user-space).
328 extern int lttng_start_tracing(const char *session_name
);
331 * Stop tracing for *all* registered traces (kernel and user-space).
333 extern int lttng_stop_tracing(const char *session_name
);
336 * Add context to event(s) for a specific channel (or for all).
338 * If event_name is NULL, the context is applied to all events of the channel.
339 * If channel_name is NULL, a lookup of the event's channel is done.
340 * If both are NULL, the context is applied to all events of all channels.
342 extern int lttng_add_context(struct lttng_handle
*handle
,
343 struct lttng_event_context
*ctx
, const char *event_name
,
344 const char *channel_name
);
347 * Create or enable a kernel event (or events) for a channel.
349 * If the event you are trying to enable does not exist, it will be created,
350 * else it is enabled.
351 * If event_name is NULL, all events are enabled.
352 * If channel_name is NULL, the default channel is used (channel0).
354 extern int lttng_enable_event(struct lttng_handle
*handle
,
355 struct lttng_event
*ev
, const char *channel_name
);
358 * Create or enable a kernel channel.
359 * The channel name cannot be NULL.
361 extern int lttng_enable_channel(struct lttng_handle
*handle
,
362 struct lttng_channel
*chan
);
365 * Disable kernel event(s) of a channel and domain.
367 * If event_name is NULL, all events are disabled.
368 * If channel_name is NULL, the default channel is used (channel0).
370 extern int lttng_disable_event(struct lttng_handle
*handle
,
371 const char *name
, const char *channel_name
);
374 * Disable kernel channel.
376 * The channel name cannot be NULL.
378 extern int lttng_disable_channel(struct lttng_handle
*handle
,
382 * Calibrate LTTng overhead.
384 extern int lttng_calibrate(struct lttng_handle
*handle
,
385 struct lttng_calibrate
*calibrate
);
388 * Set the default channel attributes for a specific domain and an allocated
389 * lttng_channel_attr pointer.
391 * If either or both of the arguments are NULL, nothing happens.
393 extern void lttng_channel_set_default_attr(struct lttng_domain
*domain
,
394 struct lttng_channel_attr
*attr
);
396 #endif /* _LTTNG_H */