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
,
75 enum lttng_event_output
{
76 LTTNG_EVENT_SPLICE
= 0,
80 /* Event context possible type */
81 enum lttng_event_context_type
{
82 LTTNG_EVENT_CONTEXT_PID
= 0,
83 LTTNG_EVENT_CONTEXT_PERF_COUNTER
= 1,
84 LTTNG_EVENT_CONTEXT_COMM
= 2,
85 LTTNG_EVENT_CONTEXT_PRIO
= 3,
86 LTTNG_EVENT_CONTEXT_NICE
= 4,
87 LTTNG_EVENT_CONTEXT_VPID
= 5,
88 LTTNG_EVENT_CONTEXT_TID
= 6,
89 LTTNG_EVENT_CONTEXT_VTID
= 7,
90 LTTNG_EVENT_CONTEXT_PPID
= 8,
91 LTTNG_EVENT_CONTEXT_VPPID
= 9,
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 enum lttng_event_type type
;
147 /* Per event type configuration */
149 struct lttng_event_probe_attr probe
;
150 struct lttng_event_function_attr ftrace
;
155 * Tracer channel attributes. For both kernel and user-space.
157 struct lttng_channel_attr
{
158 int overwrite
; /* 1: overwrite, 0: discard */
159 uint64_t subbuf_size
; /* bytes */
160 uint64_t num_subbuf
; /* power of 2 */
161 unsigned int switch_timer_interval
; /* usec */
162 unsigned int read_timer_interval
; /* usec */
163 enum lttng_event_output output
; /* splice, mmap */
167 * Channel information structure. For both kernel and user-space.
169 struct lttng_channel
{
172 struct lttng_channel_attr attr
;
175 struct lttng_calibrate
{
176 enum lttng_calibrate_type type
;
180 * Basic session information.
182 * This is an 'output data' meaning that it only comes *from* the session
183 * daemon *to* the lttng client. It's basically a 'human' representation of
184 * tracing entities (here a session).
186 struct lttng_session
{
188 /* The path where traces are written */
193 * Handle used as a context for commands.
195 struct lttng_handle
{
196 char session_name
[NAME_MAX
];
197 struct lttng_domain domain
;
201 * Public LTTng control API
203 * For functions having a lttng domain type as parameter, if a bad value is
204 * given, NO default is applied and an error is returned.
206 * On success, all functions of the API return 0 or the size of the allocated
209 * On error, a negative value is returned being a specific lttng-tools error
210 * code which can be humanly interpreted with lttng_get_readable_code(err).
214 * Create an handle used as a context for every request made to the library.
216 * This handle contains the session name and lttng domain on which the command
217 * will be executed on.
219 extern struct lttng_handle
*lttng_create_handle(const char *session_name
,
220 struct lttng_domain
*domain
);
223 * Destroy an handle. This will simply free(3) the data pointer returned by
224 * lttng_create_handle() and rendering it unsuable.
226 extern void lttng_destroy_handle(struct lttng_handle
*handle
);
229 * Create tracing session using a name and a path where trace will be written.
231 extern int lttng_create_session(const char *name
, const char *path
);
234 * Destroy tracing session.
236 * The session will not be useable anymore, tracing will stopped for all
237 * registered trace and tracing buffers will be flushed.
239 extern int lttng_destroy_session(struct lttng_handle
*handle
);
242 * List all tracing sessions.
244 * Return the size of the "lttng_session" array. Caller must free(3).
246 extern int lttng_list_sessions(struct lttng_session
**sessions
);
249 * List registered domain(s) of a session.
251 * Return the size of the "lttng_domain" array. Caller must free(3).
253 extern int lttng_list_domains(struct lttng_handle
*handle
,
254 struct lttng_domain
**domains
);
257 * List channel(s) of a session.
259 * Return the size of the "lttng_channel" array. Caller must free(3).
261 extern int lttng_list_channels(struct lttng_handle
*handle
,
262 struct lttng_channel
**channels
);
265 * List event(s) of a session channel.
267 * Return the size of the "lttng_event" array. Caller must free(3).
269 extern int lttng_list_events(struct lttng_handle
*handle
,
270 const char *channel_name
, struct lttng_event
**events
);
273 * List available tracepoints of a specific lttng domain.
275 * Return the size of the "lttng_event" array. Caller must free(3).
277 extern int lttng_list_tracepoints(struct lttng_handle
*handle
,
278 struct lttng_event
**events
);
281 * Check if a session daemon is alive.
283 extern int lttng_session_daemon_alive(void);
286 * Set tracing group for the *current* flow of execution.
288 extern int lttng_set_tracing_group(const char *name
);
291 * Return a human readable error message of a lttng-tools error code.
293 * Parameter MUST be a negative value or else you'll get a generic message.
295 extern const char *lttng_get_readable_code(int code
);
298 * This call permits to register an "outside consumer" to a session and a lttng
299 * domain. No consumer will be spawned and all fds/commands will go through the
300 * socket path given (socket_path).
302 * NOTE: At the moment, if you use the liblttngkconsumerd, you can only use the
303 * command socket. The error socket is not supported yet for roaming consumers.
305 extern int lttng_register_consumer(struct lttng_handle
*handle
,
306 const char *socket_path
);
309 * Start tracing for *all* registered trace (kernel and user-space).
311 extern int lttng_start_tracing(struct lttng_handle
*handle
);
314 * Stop tracing for *all* registered trace (kernel and user-space).
316 extern int lttng_stop_tracing(struct lttng_handle
*handle
);
319 * Add context to event for a specific channel.
321 * If event_name is NULL, the context is applied to all event of the channel.
322 * If channel_name is NULL, a lookup of the event's channel is done.
323 * If both are NULL, the context is applied on all events of all channels.
325 extern int lttng_add_context(struct lttng_handle
*handle
,
326 struct lttng_event_context
*ctx
, const char *event_name
,
327 const char *channel_name
);
330 * Create or enable a kernel event.
332 * If the event you are trying to enable does not exist, it will be created,
333 * else it is enabled.
335 * If channel_name is NULL, the default channel is used (channel0).
337 extern int lttng_enable_event(struct lttng_handle
*handle
,
338 struct lttng_event
*ev
, const char *channel_name
);
341 * Create or enable a kernel channel.
343 * If name is NULL, the default channel is enabled (channel0).
345 extern int lttng_enable_channel(struct lttng_handle
*handle
,
346 struct lttng_channel
*chan
);
349 * Disable kernel event.
351 * If channel_name is NULL, the default channel is used (channel0).
353 extern int lttng_disable_event(struct lttng_handle
*handle
,
354 const char *name
, const char *channel_name
);
357 * Disable kernel channel.
359 * If channel_name is NULL, the default channel is disabled (channel0).
361 extern int lttng_disable_channel(struct lttng_handle
*handle
,
365 * Calibrate LTTng overhead.
367 extern int lttng_calibrate(struct lttng_handle
*handle
,
368 struct lttng_calibrate
*calibrate
);
370 #endif /* _LTTNG_H */