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 128
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
{
64 LTTNG_EVENT_TRACEPOINT
,
67 LTTNG_EVENT_FUNCTION_ENTRY
,
73 enum lttng_event_output
{
74 LTTNG_EVENT_SPLICE
= 0,
78 /* Event context possible type */
79 enum lttng_event_context_type
{
80 LTTNG_EVENT_CONTEXT_PID
= 0,
81 LTTNG_EVENT_CONTEXT_PERF_COUNTER
= 1,
82 LTTNG_EVENT_CONTEXT_COMM
= 2,
83 LTTNG_EVENT_CONTEXT_PRIO
= 3,
84 LTTNG_EVENT_CONTEXT_NICE
= 4,
85 LTTNG_EVENT_CONTEXT_VPID
= 5,
86 LTTNG_EVENT_CONTEXT_TID
= 6,
87 LTTNG_EVENT_CONTEXT_VTID
= 7,
88 LTTNG_EVENT_CONTEXT_PPID
= 8,
89 LTTNG_EVENT_CONTEXT_VPPID
= 9,
92 enum lttng_calibrate_type
{
93 LTTNG_CALIBRATE_FUNCTION
= 0,
97 enum lttng_domain_type type
;
100 char exec_name
[NAME_MAX
];
104 /* Perf counter attributes */
105 struct lttng_event_perf_counter_ctx
{
108 char name
[LTTNG_SYMBOL_NAME_LEN
];
111 /* Event/Channel context */
112 struct lttng_event_context
{
113 enum lttng_event_context_type ctx
;
115 struct lttng_event_perf_counter_ctx perf_counter
;
122 * Either addr is used or symbol_name and offset.
124 struct lttng_event_probe_attr
{
128 char symbol_name
[LTTNG_SYMBOL_NAME_LEN
];
134 struct lttng_event_function_attr
{
135 char symbol_name
[LTTNG_SYMBOL_NAME_LEN
];
139 * Generic lttng event
142 char name
[LTTNG_SYMBOL_NAME_LEN
];
143 enum lttng_event_type type
;
145 /* Per event type configuration */
147 struct lttng_event_probe_attr probe
;
148 struct lttng_event_function_attr ftrace
;
153 * Tracer channel attributes. For both kernel and user-space.
155 struct lttng_channel_attr
{
156 int overwrite
; /* 1: overwrite, 0: discard */
157 uint64_t subbuf_size
; /* bytes */
158 uint64_t num_subbuf
; /* power of 2 */
159 unsigned int switch_timer_interval
; /* usec */
160 unsigned int read_timer_interval
; /* usec */
161 enum lttng_event_output output
; /* splice, mmap */
165 * Channel information structure. For both kernel and user-space.
167 struct lttng_channel
{
170 struct lttng_channel_attr attr
;
173 struct lttng_calibrate
{
174 enum lttng_calibrate_type type
;
178 * Basic session information.
180 * This is an 'output data' meaning that it only comes *from* the session
181 * daemon *to* the lttng client. It's basically a 'human' representation of
182 * tracing entities (here a session).
184 struct lttng_session
{
186 /* The path where traces are written */
191 * Handle used as a context for commands.
193 struct lttng_handle
{
194 char session_name
[NAME_MAX
];
195 struct lttng_domain domain
;
199 * Public LTTng control API
201 * For functions having a lttng domain type as parameter, if a bad value is
202 * given, NO default is applied and an error is returned.
204 * On success, all functions of the API return 0 or the size of the allocated
207 * On error, a negative value is returned being a specific lttng-tools error
208 * code which can be humanly interpreted with lttng_get_readable_code(err).
212 * Create an handle used as a context for every request made to the library.
214 * This handle contains the session name and lttng domain on which the command
215 * will be executed on.
217 extern struct lttng_handle
*lttng_create_handle(const char *session_name
,
218 struct lttng_domain
*domain
);
221 * Destroy an handle. This will simply free(3) the data pointer returned by
222 * lttng_create_handle() and rendering it unsuable.
224 extern void lttng_destroy_handle(struct lttng_handle
*handle
);
227 * Create tracing session using a name and a path where trace will be written.
229 extern int lttng_create_session(const char *name
, const char *path
);
232 * Destroy tracing session.
234 * The session will not be useable anymore, tracing will stopped for all
235 * registered trace and tracing buffers will be flushed.
237 extern int lttng_destroy_session(struct lttng_handle
*handle
);
240 * List all tracing sessions.
242 * Return the size of the "lttng_session" array. Caller must free(3).
244 extern int lttng_list_sessions(struct lttng_session
**sessions
);
247 * List registered domain(s) of a session.
249 * Return the size of the "lttng_domain" array. Caller must free(3).
251 extern int lttng_list_domains(struct lttng_handle
*handle
,
252 struct lttng_domain
**domains
);
255 * List channel(s) of a session.
257 * Return the size of the "lttng_channel" array. Caller must free(3).
259 extern int lttng_list_channels(struct lttng_handle
*handle
,
260 struct lttng_channel
**channels
);
263 * List event(s) of a session channel.
265 * Return the size of the "lttng_event" array. Caller must free(3).
267 extern int lttng_list_events(struct lttng_handle
*handle
,
268 const char *channel_name
, struct lttng_event
**events
);
271 * List available tracepoints of a specific lttng domain.
273 * Return the size of the "lttng_event" array. Caller must free(3).
275 extern int lttng_list_tracepoints(struct lttng_handle
*handle
,
276 struct lttng_event
**events
);
279 * Check if a session daemon is alive.
281 extern int lttng_session_daemon_alive(void);
284 * Set tracing group for the *current* flow of execution.
286 extern int lttng_set_tracing_group(const char *name
);
289 * Return a human readable error message of a lttng-tools error code.
291 * Parameter MUST be a negative value or else you'll get a generic message.
293 extern const char *lttng_get_readable_code(int code
);
296 * This call permits to register an "outside consumer" to a session and a lttng
297 * domain. No consumer will be spawned and all fds/commands will go through the
298 * socket path given (socket_path).
300 * NOTE: At the moment, if you use the liblttngkconsumerd, you can only use the
301 * command socket. The error socket is not supported yet for roaming consumers.
303 extern int lttng_register_consumer(struct lttng_handle
*handle
,
304 const char *socket_path
);
307 * Start tracing for *all* registered trace (kernel and user-space).
309 extern int lttng_start_tracing(struct lttng_handle
*handle
);
312 * Stop tracing for *all* registered trace (kernel and user-space).
314 extern int lttng_stop_tracing(struct lttng_handle
*handle
);
317 * Add context to event for a specific channel.
319 * If event_name is NULL, the context is applied to all event of the channel.
320 * If channel_name is NULL, a lookup of the event's channel is done.
321 * If both are NULL, the context is applied on all events of all channels.
323 extern int lttng_add_context(struct lttng_handle
*handle
,
324 struct lttng_event_context
*ctx
, const char *event_name
,
325 const char *channel_name
);
328 * Create or enable a kernel event.
330 * If the event you are trying to enable does not exist, it will be created,
331 * else it is enabled.
333 * If channel_name is NULL, the default channel is used (channel0).
335 extern int lttng_enable_event(struct lttng_handle
*handle
,
336 struct lttng_event
*ev
, const char *channel_name
);
339 * Create or enable a kernel channel.
341 * If name is NULL, the default channel is enabled (channel0).
343 extern int lttng_enable_channel(struct lttng_handle
*handle
,
344 struct lttng_channel
*chan
);
347 * Disable kernel event.
349 * If channel_name is NULL, the default channel is used (channel0).
351 extern int lttng_disable_event(struct lttng_handle
*handle
,
352 const char *name
, const char *channel_name
);
355 * Disable kernel channel.
357 * If channel_name is NULL, the default channel is disabled (channel0).
359 extern int lttng_disable_channel(struct lttng_handle
*handle
,
363 * Calibrate LTTng overhead.
365 extern int lttng_calibrate(struct lttng_handle
*handle
,
366 struct lttng_calibrate
*calibrate
);
368 #endif /* _LTTNG_H */