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
{
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,
76 enum lttng_event_output
{
77 LTTNG_EVENT_SPLICE
= 0,
81 /* Event context possible type */
82 enum 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,
95 enum lttng_calibrate_type
{
96 LTTNG_CALIBRATE_FUNCTION
= 0,
100 enum lttng_domain_type type
;
103 char exec_name
[NAME_MAX
];
107 /* Perf counter attributes */
108 struct lttng_event_perf_counter_ctx
{
111 char name
[LTTNG_SYMBOL_NAME_LEN
];
114 /* Event/Channel context */
115 struct lttng_event_context
{
116 enum lttng_event_context_type ctx
;
118 struct lttng_event_perf_counter_ctx perf_counter
;
125 * Either addr is used or symbol_name and offset.
127 struct lttng_event_probe_attr
{
131 char symbol_name
[LTTNG_SYMBOL_NAME_LEN
];
137 struct lttng_event_function_attr
{
138 char symbol_name
[LTTNG_SYMBOL_NAME_LEN
];
142 * Generic lttng event
145 char name
[LTTNG_SYMBOL_NAME_LEN
];
146 enum lttng_event_type type
;
149 /* Per event type configuration */
151 struct lttng_event_probe_attr probe
;
152 struct lttng_event_function_attr ftrace
;
157 * Tracer channel attributes. For both kernel and user-space.
159 struct lttng_channel_attr
{
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 */
165 enum lttng_event_output output
; /* splice, mmap */
169 * Channel information structure. For both kernel and user-space.
171 struct lttng_channel
{
174 struct lttng_channel_attr attr
;
177 struct lttng_calibrate
{
178 enum lttng_calibrate_type type
;
182 * Basic session information.
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).
188 struct lttng_session
{
190 /* The path where traces are written */
192 uint32_t enabled
; /* enabled/started: 1, disabled/stopped: 0 */
196 * Handle used as a context for commands.
198 struct lttng_handle
{
199 char session_name
[NAME_MAX
];
200 struct lttng_domain domain
;
204 * Public LTTng control API
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.
209 * On success, all functions of the API return 0 or the size of the allocated
212 * On error, a negative value is returned being a specific lttng-tools error
213 * code which can be humanly interpreted with lttng_strerror(err).
217 * Create an handle used as a context for every request made to the library.
219 * This handle contains the session name and lttng domain on which the command
220 * will be executed on.
222 extern struct lttng_handle
*lttng_create_handle(const char *session_name
,
223 struct lttng_domain
*domain
);
226 * Destroy an handle. This will simply free(3) the data pointer returned by
227 * lttng_create_handle() and rendering it unsuable.
229 extern void lttng_destroy_handle(struct lttng_handle
*handle
);
232 * Create tracing session using a name and a path where trace will be written.
234 extern int lttng_create_session(const char *name
, const char *path
);
237 * Destroy tracing session.
239 * The session will not be useable anymore, tracing will stopped for all
240 * registered trace and tracing buffers will be flushed.
242 extern int lttng_destroy_session(struct lttng_handle
*handle
);
245 * List all tracing sessions.
247 * Return the size of the "lttng_session" array. Caller must free(3).
249 extern int lttng_list_sessions(struct lttng_session
**sessions
);
252 * List registered domain(s) of a session.
254 * Return the size of the "lttng_domain" array. Caller must free(3).
256 extern int lttng_list_domains(struct lttng_handle
*handle
,
257 struct lttng_domain
**domains
);
260 * List channel(s) of a session.
262 * Return the size of the "lttng_channel" array. Caller must free(3).
264 extern int lttng_list_channels(struct lttng_handle
*handle
,
265 struct lttng_channel
**channels
);
268 * List event(s) of a session channel.
270 * Return the size of the "lttng_event" array. Caller must free(3).
272 extern int lttng_list_events(struct lttng_handle
*handle
,
273 const char *channel_name
, struct lttng_event
**events
);
276 * List available tracepoints of a specific lttng domain.
278 * Return the size of the "lttng_event" array. Caller must free(3).
280 extern int lttng_list_tracepoints(struct lttng_handle
*handle
,
281 struct lttng_event
**events
);
284 * Check if a session daemon is alive.
286 extern int lttng_session_daemon_alive(void);
289 * Set tracing group for the *current* flow of execution.
291 extern int lttng_set_tracing_group(const char *name
);
294 * Return a human readable error message of a lttng-tools error code.
296 * Parameter MUST be a negative value or else you'll get a generic message.
298 extern const char *lttng_strerror(int code
);
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).
305 * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
306 * command socket. The error socket is not supported yet for roaming consumers.
308 extern int lttng_register_consumer(struct lttng_handle
*handle
,
309 const char *socket_path
);
312 * Start tracing for *all* registered trace (kernel and user-space).
314 extern int lttng_start_tracing(struct lttng_handle
*handle
);
317 * Stop tracing for *all* registered trace (kernel and user-space).
319 extern int lttng_stop_tracing(struct lttng_handle
*handle
);
322 * Add context to event for a specific channel.
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.
328 extern int lttng_add_context(struct lttng_handle
*handle
,
329 struct lttng_event_context
*ctx
, const char *event_name
,
330 const char *channel_name
);
333 * Create or enable a kernel event.
335 * If the event you are trying to enable does not exist, it will be created,
336 * else it is enabled.
338 * If channel_name is NULL, the default channel is used (channel0).
340 extern int lttng_enable_event(struct lttng_handle
*handle
,
341 struct lttng_event
*ev
, const char *channel_name
);
344 * Create or enable a kernel channel.
346 * If name is NULL, the default channel is enabled (channel0).
348 extern int lttng_enable_channel(struct lttng_handle
*handle
,
349 struct lttng_channel
*chan
);
352 * Disable kernel event.
354 * If channel_name is NULL, the default channel is used (channel0).
356 extern int lttng_disable_event(struct lttng_handle
*handle
,
357 const char *name
, const char *channel_name
);
360 * Disable kernel channel.
362 * If channel_name is NULL, the default channel is disabled (channel0).
364 extern int lttng_disable_channel(struct lttng_handle
*handle
,
368 * Calibrate LTTng overhead.
370 extern int lttng_calibrate(struct lttng_handle
*handle
,
371 struct lttng_calibrate
*calibrate
);
373 #endif /* _LTTNG_H */