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
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.
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.
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
28 #include <sys/types.h>
30 /* Default unix group name for tracing. */
31 #define LTTNG_DEFAULT_TRACING_GROUP "tracing"
33 /* Environment variable to set session daemon binary path. */
34 #define LTTNG_SESSIOND_PATH_ENV "LTTNG_SESSIOND_PATH"
36 /* Default trace output directory name */
37 #define LTTNG_DEFAULT_TRACE_DIR_NAME "lttng-traces"
40 * Event symbol length. Copied from LTTng kernel ABI.
42 #define LTTNG_SYMBOL_NAME_LEN 256
45 * Every lttng_event_* structure both apply to kernel event and user-space
50 * Domain type are the different possible tracers.
52 enum lttng_domain_type
{
53 LTTNG_DOMAIN_KERNEL
= 1,
55 LTTNG_DOMAIN_UST_EXEC_NAME
= 3,
56 LTTNG_DOMAIN_UST_PID
= 4,
57 LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN
= 5,
61 * Instrumentation type of tracing event.
63 enum lttng_event_type
{
65 LTTNG_EVENT_TRACEPOINT
= 0,
66 LTTNG_EVENT_PROBE
= 1,
67 LTTNG_EVENT_FUNCTION
= 2,
68 LTTNG_EVENT_FUNCTION_ENTRY
= 3,
70 LTTNG_EVENT_SYSCALL
= 5,
71 LTTNG_EVENT_TRACEPOINT_LOGLEVEL
= 6,
77 enum lttng_event_output
{
78 LTTNG_EVENT_SPLICE
= 0,
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,
96 enum lttng_calibrate_type
{
97 LTTNG_CALIBRATE_FUNCTION
= 0,
100 struct lttng_domain
{
101 enum lttng_domain_type type
;
104 char exec_name
[NAME_MAX
];
108 /* Perf counter attributes */
109 struct lttng_event_perf_counter_ctx
{
112 char name
[LTTNG_SYMBOL_NAME_LEN
];
115 /* Event/Channel context */
116 struct lttng_event_context
{
117 enum lttng_event_context_type ctx
;
119 struct lttng_event_perf_counter_ctx perf_counter
;
126 * Either addr is used or symbol_name and offset.
128 struct lttng_event_probe_attr
{
132 char symbol_name
[LTTNG_SYMBOL_NAME_LEN
];
138 struct lttng_event_function_attr
{
139 char symbol_name
[LTTNG_SYMBOL_NAME_LEN
];
143 * Generic lttng event
146 char name
[LTTNG_SYMBOL_NAME_LEN
];
147 char loglevel
[LTTNG_SYMBOL_NAME_LEN
];
148 enum lttng_event_type type
;
151 /* Per event type configuration */
153 struct lttng_event_probe_attr probe
;
154 struct lttng_event_function_attr ftrace
;
159 * Tracer channel attributes. For both kernel and user-space.
161 struct lttng_channel_attr
{
162 int overwrite
; /* 1: overwrite, 0: discard */
163 uint64_t subbuf_size
; /* bytes */
164 uint64_t num_subbuf
; /* power of 2 */
165 unsigned int switch_timer_interval
; /* usec */
166 unsigned int read_timer_interval
; /* usec */
167 enum lttng_event_output output
; /* splice, mmap */
171 * Channel information structure. For both kernel and user-space.
173 struct lttng_channel
{
176 struct lttng_channel_attr attr
;
179 struct lttng_calibrate
{
180 enum lttng_calibrate_type type
;
184 * Basic session information.
186 * This is an 'output data' meaning that it only comes *from* the session
187 * daemon *to* the lttng client. It's basically a 'human' representation of
188 * tracing entities (here a session).
190 struct lttng_session
{
192 /* The path where traces are written */
194 uint32_t enabled
; /* enabled/started: 1, disabled/stopped: 0 */
198 * Handle used as a context for commands.
200 struct lttng_handle
{
201 char session_name
[NAME_MAX
];
202 struct lttng_domain domain
;
206 * Public LTTng control API
208 * For functions having a lttng domain type as parameter, if a bad value is
209 * given, NO default is applied and an error is returned.
211 * On success, all functions of the API return 0 or the size of the allocated
214 * On error, a negative value is returned being a specific lttng-tools error
215 * code which can be humanly interpreted with lttng_strerror(err).
219 * Create an handle used as a context for every request made to the library.
221 * This handle contains the session name and lttng domain on which the command
222 * will be executed on.
224 extern struct lttng_handle
*lttng_create_handle(const char *session_name
,
225 struct lttng_domain
*domain
);
228 * Destroy an handle. This will simply free(3) the data pointer returned by
229 * lttng_create_handle() and rendering it unsuable.
231 extern void lttng_destroy_handle(struct lttng_handle
*handle
);
234 * Create tracing session using a name and a path where trace will be written.
236 extern int lttng_create_session(const char *name
, const char *path
);
239 * Destroy tracing session.
241 * The session will not be useable anymore, tracing will stopped for all
242 * registered trace and tracing buffers will be flushed.
244 extern int lttng_destroy_session(struct lttng_handle
*handle
);
247 * List all tracing sessions.
249 * Return the size of the "lttng_session" array. Caller must free(3).
251 extern int lttng_list_sessions(struct lttng_session
**sessions
);
254 * List registered domain(s) of a session.
256 * Return the size of the "lttng_domain" array. Caller must free(3).
258 extern int lttng_list_domains(struct lttng_handle
*handle
,
259 struct lttng_domain
**domains
);
262 * List channel(s) of a session.
264 * Return the size of the "lttng_channel" array. Caller must free(3).
266 extern int lttng_list_channels(struct lttng_handle
*handle
,
267 struct lttng_channel
**channels
);
270 * List event(s) of a session channel.
272 * Return the size of the "lttng_event" array. Caller must free(3).
274 extern int lttng_list_events(struct lttng_handle
*handle
,
275 const char *channel_name
, struct lttng_event
**events
);
278 * List available tracepoints of a specific lttng domain.
280 * Return the size of the "lttng_event" array. Caller must free(3).
282 extern int lttng_list_tracepoints(struct lttng_handle
*handle
,
283 struct lttng_event
**events
);
286 * Check if a session daemon is alive.
288 extern int lttng_session_daemon_alive(void);
291 * Set tracing group for the *current* flow of execution.
293 extern int lttng_set_tracing_group(const char *name
);
296 * Return a human readable error message of a lttng-tools error code.
298 * Parameter MUST be a negative value or else you'll get a generic message.
300 extern const char *lttng_strerror(int code
);
303 * This call permits to register an "outside consumer" to a session and a lttng
304 * domain. No consumer will be spawned and all fds/commands will go through the
305 * socket path given (socket_path).
307 * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
308 * command socket. The error socket is not supported yet for roaming consumers.
310 extern int lttng_register_consumer(struct lttng_handle
*handle
,
311 const char *socket_path
);
314 * Start tracing for *all* registered trace (kernel and user-space).
316 extern int lttng_start_tracing(struct lttng_handle
*handle
);
319 * Stop tracing for *all* registered trace (kernel and user-space).
321 extern int lttng_stop_tracing(struct lttng_handle
*handle
);
324 * Add context to event for a specific channel.
326 * If event_name is NULL, the context is applied to all event of the channel.
327 * If channel_name is NULL, a lookup of the event's channel is done.
328 * If both are NULL, the context is applied on all events of all channels.
330 extern int lttng_add_context(struct lttng_handle
*handle
,
331 struct lttng_event_context
*ctx
, const char *event_name
,
332 const char *channel_name
);
335 * Create or enable a kernel event.
337 * If the event you are trying to enable does not exist, it will be created,
338 * else it is enabled.
340 * If channel_name is NULL, the default channel is used (channel0).
342 extern int lttng_enable_event(struct lttng_handle
*handle
,
343 struct lttng_event
*ev
, const char *channel_name
);
346 * Create or enable a kernel channel.
348 * If name is NULL, the default channel is enabled (channel0).
350 extern int lttng_enable_channel(struct lttng_handle
*handle
,
351 struct lttng_channel
*chan
);
354 * Disable kernel event.
356 * If channel_name is NULL, the default channel is used (channel0).
358 extern int lttng_disable_event(struct lttng_handle
*handle
,
359 const char *name
, const char *channel_name
);
362 * Disable kernel channel.
364 * If channel_name is NULL, the default channel is disabled (channel0).
366 extern int lttng_disable_channel(struct lttng_handle
*handle
,
370 * Calibrate LTTng overhead.
372 extern int lttng_calibrate(struct lttng_handle
*handle
,
373 struct lttng_calibrate
*calibrate
);
376 * Set the default channel attributes for a specific domain and an allocated
377 * lttng_channel_attr pointer.
379 extern void lttng_channel_set_default_attr(struct lttng_domain
*domain
,
380 struct lttng_channel_attr
*attr
);
382 #endif /* _LTTNG_H */