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,
71 * Loglevel information.
73 enum lttng_loglevel_type
{
74 LTTNG_EVENT_LOGLEVEL_ALL
= 0,
75 LTTNG_EVENT_LOGLEVEL_RANGE
= 1,
76 LTTNG_EVENT_LOGLEVEL_SINGLE
= 2,
82 enum lttng_event_output
{
83 LTTNG_EVENT_SPLICE
= 0,
87 /* Event context possible type */
88 enum lttng_event_context_type
{
89 LTTNG_EVENT_CONTEXT_PID
= 0,
90 LTTNG_EVENT_CONTEXT_PERF_COUNTER
= 1,
91 LTTNG_EVENT_CONTEXT_PROCNAME
= 2,
92 LTTNG_EVENT_CONTEXT_PRIO
= 3,
93 LTTNG_EVENT_CONTEXT_NICE
= 4,
94 LTTNG_EVENT_CONTEXT_VPID
= 5,
95 LTTNG_EVENT_CONTEXT_TID
= 6,
96 LTTNG_EVENT_CONTEXT_VTID
= 7,
97 LTTNG_EVENT_CONTEXT_PPID
= 8,
98 LTTNG_EVENT_CONTEXT_VPPID
= 9,
99 LTTNG_EVENT_CONTEXT_PTHREAD_ID
= 10,
102 enum lttng_calibrate_type
{
103 LTTNG_CALIBRATE_FUNCTION
= 0,
106 struct lttng_domain
{
107 enum lttng_domain_type type
;
110 char exec_name
[NAME_MAX
];
114 /* Perf counter attributes */
115 struct lttng_event_perf_counter_ctx
{
118 char name
[LTTNG_SYMBOL_NAME_LEN
];
121 /* Event/Channel context */
122 struct lttng_event_context
{
123 enum lttng_event_context_type ctx
;
125 struct lttng_event_perf_counter_ctx perf_counter
;
132 * Either addr is used or symbol_name and offset.
134 struct lttng_event_probe_attr
{
138 char symbol_name
[LTTNG_SYMBOL_NAME_LEN
];
144 struct lttng_event_function_attr
{
145 char symbol_name
[LTTNG_SYMBOL_NAME_LEN
];
149 * Generic lttng event
152 enum lttng_event_type type
;
153 char name
[LTTNG_SYMBOL_NAME_LEN
];
155 enum lttng_loglevel_type loglevel_type
;
160 /* Per event type configuration */
162 struct lttng_event_probe_attr probe
;
163 struct lttng_event_function_attr ftrace
;
168 * Tracer channel attributes. For both kernel and user-space.
170 struct lttng_channel_attr
{
171 int overwrite
; /* 1: overwrite, 0: discard */
172 uint64_t subbuf_size
; /* bytes */
173 uint64_t num_subbuf
; /* power of 2 */
174 unsigned int switch_timer_interval
; /* usec */
175 unsigned int read_timer_interval
; /* usec */
176 enum lttng_event_output output
; /* splice, mmap */
180 * Channel information structure. For both kernel and user-space.
182 struct lttng_channel
{
183 char name
[LTTNG_SYMBOL_NAME_LEN
];
185 struct lttng_channel_attr attr
;
188 struct lttng_calibrate
{
189 enum lttng_calibrate_type type
;
193 * Basic session information.
195 * This is an 'output data' meaning that it only comes *from* the session
196 * daemon *to* the lttng client. It's basically a 'human' representation of
197 * tracing entities (here a session).
199 struct lttng_session
{
201 /* The path where traces are written */
203 uint32_t enabled
; /* enabled/started: 1, disabled/stopped: 0 */
207 * Handle used as a context for commands.
209 struct lttng_handle
{
210 char session_name
[NAME_MAX
];
211 struct lttng_domain domain
;
215 * Public LTTng control API
217 * For functions having an lttng domain type as parameter, if a bad value is
218 * given, NO default is applied and an error is returned.
220 * On success, all functions of the API return 0 or the size of the allocated
223 * On error, a negative value is returned being a specific lttng-tools error
224 * code which can be humanly interpreted with lttng_strerror(err).
226 * Exceptions to this are noted below.
230 * Create a handle used as a context for every request made to the library.
232 * This handle contains the session name and lttng domain on which the command
234 * The returned pointer will be NULL in case of malloc() error.
236 extern struct lttng_handle
*lttng_create_handle(const char *session_name
,
237 struct lttng_domain
*domain
);
240 * Destroy a handle. This will simply free(3) the data pointer returned by
241 * lttng_create_handle(), rendering it unusable.
243 extern void lttng_destroy_handle(struct lttng_handle
*handle
);
246 * Create a tracing session using a name and a path where the trace will be
249 extern int lttng_create_session(const char *name
, const char *path
);
252 * Destroy a tracing session.
254 * The session will not be usable anymore, tracing will be stopped for all
255 * registered traces, and the tracing buffers will be flushed.
257 extern int lttng_destroy_session(const char *name
);
260 * List all the tracing sessions.
262 * Return the size (number of entries) of the "lttng_session" array. Caller
265 extern int lttng_list_sessions(struct lttng_session
**sessions
);
268 * List the registered domain(s) of a session.
270 * Return the size (number of entries) of the "lttng_domain" array. Caller
273 extern int lttng_list_domains(const char *session_name
,
274 struct lttng_domain
**domains
);
277 * List the channel(s) of a session.
279 * Return the size (number of entries) of the "lttng_channel" array. Caller
282 extern int lttng_list_channels(struct lttng_handle
*handle
,
283 struct lttng_channel
**channels
);
286 * List the event(s) of a session channel.
288 * Return the size (number of entries) of the "lttng_event" array.
289 * Caller must free(3).
291 extern int lttng_list_events(struct lttng_handle
*handle
,
292 const char *channel_name
, struct lttng_event
**events
);
295 * List the available tracepoints of a specific lttng domain.
297 * Return the size (number of entries) of the "lttng_event" array.
298 * Caller must free(3).
300 extern int lttng_list_tracepoints(struct lttng_handle
*handle
,
301 struct lttng_event
**events
);
304 * Check if a session daemon is alive.
306 * Return 1 if alive or 0 if not. On error returns a negative value.
308 extern int lttng_session_daemon_alive(void);
311 * Set the tracing group for the *current* flow of execution.
313 * On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
315 extern int lttng_set_tracing_group(const char *name
);
318 * Return a human-readable error message for an lttng-tools error code.
320 * Parameter MUST be a negative value or else you'll get a generic message.
322 extern const char *lttng_strerror(int code
);
325 * This call registers an "outside consumer" for a session and an lttng domain.
326 * No consumer will be spawned and all fds/commands will go through the socket
327 * path given (socket_path).
329 * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
330 * command socket. The error socket is not supported yet for roaming consumers.
332 extern int lttng_register_consumer(struct lttng_handle
*handle
,
333 const char *socket_path
);
336 * Start tracing for *all* registered traces (kernel and user-space).
338 extern int lttng_start_tracing(const char *session_name
);
341 * Stop tracing for *all* registered traces (kernel and user-space).
343 extern int lttng_stop_tracing(const char *session_name
);
346 * Add context to event(s) for a specific channel (or for all).
348 * If event_name is NULL, the context is applied to all events of the channel.
349 * If channel_name is NULL, a lookup of the event's channel is done.
350 * If both are NULL, the context is applied to all events of all channels.
352 extern int lttng_add_context(struct lttng_handle
*handle
,
353 struct lttng_event_context
*ctx
, const char *event_name
,
354 const char *channel_name
);
357 * Create or enable a kernel event (or events) for a channel.
359 * If the event you are trying to enable does not exist, it will be created,
360 * else it is enabled.
361 * If event_name is NULL, all events are enabled.
362 * If channel_name is NULL, the default channel is used (channel0).
364 extern int lttng_enable_event(struct lttng_handle
*handle
,
365 struct lttng_event
*ev
, const char *channel_name
);
368 * Create or enable a kernel channel.
369 * The channel name cannot be NULL.
371 extern int lttng_enable_channel(struct lttng_handle
*handle
,
372 struct lttng_channel
*chan
);
375 * Disable kernel event(s) of a channel and domain.
377 * If event_name is NULL, all events are disabled.
378 * If channel_name is NULL, the default channel is used (channel0).
380 extern int lttng_disable_event(struct lttng_handle
*handle
,
381 const char *name
, const char *channel_name
);
384 * Disable kernel channel.
386 * The channel name cannot be NULL.
388 extern int lttng_disable_channel(struct lttng_handle
*handle
,
392 * Calibrate LTTng overhead.
394 extern int lttng_calibrate(struct lttng_handle
*handle
,
395 struct lttng_calibrate
*calibrate
);
398 * Set the default channel attributes for a specific domain and an allocated
399 * lttng_channel_attr pointer.
401 * If either or both of the arguments are NULL, nothing happens.
403 extern void lttng_channel_set_default_attr(struct lttng_domain
*domain
,
404 struct lttng_channel_attr
*attr
);
406 #endif /* _LTTNG_H */