[lttng-tools.git] / include / lttng / lttng.h

/*
 * lttng.h
 *
 * Linux Trace Toolkit Control Library Header File
 *
 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation; only version 2.1 of the License.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef _LTTNG_H
#define _LTTNG_H

#include <limits.h>
#include <stdint.h>
#include <sys/types.h>

/*
 * Event symbol length. Copied from LTTng kernel ABI.
 */
#define LTTNG_SYMBOL_NAME_LEN             256

/*
 * Every lttng_event_* structure both apply to kernel event and user-space
 * event.
 */

/*
 * Domain types: the different possible tracers.
 */
enum lttng_domain_type {
	LTTNG_DOMAIN_KERNEL                   = 1,
	LTTNG_DOMAIN_UST                      = 2,

	/*
	 * For now, the domains below are not implemented. However, we keep them
	 * here in order to retain their enum values for future development. Note
	 * that it is on the roadmap to implement them.
	 *
	LTTNG_DOMAIN_UST_EXEC_NAME            = 3,
	LTTNG_DOMAIN_UST_PID                  = 4,
	LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN  = 5,
	*/
};

/*
 * Instrumentation type of tracing event.
 */
enum lttng_event_type {
	LTTNG_EVENT_ALL                       = -1,
	LTTNG_EVENT_TRACEPOINT                = 0,
	LTTNG_EVENT_PROBE                     = 1,
	LTTNG_EVENT_FUNCTION                  = 2,
	LTTNG_EVENT_FUNCTION_ENTRY            = 3,
	LTTNG_EVENT_NOOP                      = 4,
	LTTNG_EVENT_SYSCALL                   = 5,
};

/*
 * Loglevel information.
 */
enum lttng_loglevel_type {
	LTTNG_EVENT_LOGLEVEL_ALL              = 0,
	LTTNG_EVENT_LOGLEVEL_RANGE            = 1,
	LTTNG_EVENT_LOGLEVEL_SINGLE           = 2,
};

/*
 * Available loglevels.
 */
enum lttng_loglevel {
        LTTNG_LOGLEVEL_EMERG                  = 0,
        LTTNG_LOGLEVEL_ALERT                  = 1,
        LTTNG_LOGLEVEL_CRIT                   = 2,
        LTTNG_LOGLEVEL_ERR                    = 3,
        LTTNG_LOGLEVEL_WARNING                = 4,
        LTTNG_LOGLEVEL_NOTICE                 = 5,
        LTTNG_LOGLEVEL_INFO                   = 6,
        LTTNG_LOGLEVEL_DEBUG_SYSTEM           = 7,
        LTTNG_LOGLEVEL_DEBUG_PROGRAM          = 8,
        LTTNG_LOGLEVEL_DEBUG_PROCESS          = 9,
        LTTNG_LOGLEVEL_DEBUG_MODULE           = 10,
        LTTNG_LOGLEVEL_DEBUG_UNIT             = 11,
        LTTNG_LOGLEVEL_DEBUG_FUNCTION         = 12,
        LTTNG_LOGLEVEL_DEBUG_LINE             = 13,
        LTTNG_LOGLEVEL_DEBUG                  = 14,
};

/*
 * LTTng consumer mode
 */
enum lttng_event_output {
	LTTNG_EVENT_SPLICE                    = 0,
	LTTNG_EVENT_MMAP                      = 1,
};

/* Event context possible type */
enum lttng_event_context_type {
	LTTNG_EVENT_CONTEXT_PID               = 0,
	LTTNG_EVENT_CONTEXT_PERF_COUNTER      = 1,
	LTTNG_EVENT_CONTEXT_PROCNAME          = 2,
	LTTNG_EVENT_CONTEXT_PRIO              = 3,
	LTTNG_EVENT_CONTEXT_NICE              = 4,
	LTTNG_EVENT_CONTEXT_VPID              = 5,
	LTTNG_EVENT_CONTEXT_TID               = 6,
	LTTNG_EVENT_CONTEXT_VTID              = 7,
	LTTNG_EVENT_CONTEXT_PPID              = 8,
	LTTNG_EVENT_CONTEXT_VPPID             = 9,
	LTTNG_EVENT_CONTEXT_PTHREAD_ID        = 10,
};

enum lttng_calibrate_type {
	LTTNG_CALIBRATE_FUNCTION              = 0,
};

#define LTTNG_DOMAIN_PADDING1              16
#define LTTNG_DOMAIN_PADDING2              LTTNG_SYMBOL_NAME_LEN + 32
struct lttng_domain {
	enum lttng_domain_type type;
	char padding[LTTNG_DOMAIN_PADDING1];

	union {
		pid_t pid;
		char exec_name[NAME_MAX];
		char padding[LTTNG_DOMAIN_PADDING2];
	} attr;
};

/* Perf counter attributes */
#define LTTNG_PERF_EVENT_PADDING1          16
struct lttng_event_perf_counter_ctx {
	uint32_t type;
	uint64_t config;
	char name[LTTNG_SYMBOL_NAME_LEN];

	char padding[LTTNG_PERF_EVENT_PADDING1];
};

/* Event/Channel context */
#define LTTNG_EVENT_CONTEXT_PADDING1       16
#define LTTNG_EVENT_CONTEXT_PADDING2       LTTNG_SYMBOL_NAME_LEN + 32
struct lttng_event_context {
	enum lttng_event_context_type ctx;
	char padding[LTTNG_EVENT_CONTEXT_PADDING1];

	union {
		struct lttng_event_perf_counter_ctx perf_counter;
		char padding[LTTNG_EVENT_CONTEXT_PADDING2];
	} u;
};

/*
 * Event probe.
 *
 * Either addr is used or symbol_name and offset.
 */
#define LTTNG_EVENT_PROBE_PADDING1         16
struct lttng_event_probe_attr {
	uint64_t addr;

	uint64_t offset;
	char symbol_name[LTTNG_SYMBOL_NAME_LEN];

	char padding[LTTNG_EVENT_PROBE_PADDING1];
};

/*
 * Function tracer
 */
#define LTTNG_EVENT_FUNCTION_PADDING1      16
struct lttng_event_function_attr {
	char symbol_name[LTTNG_SYMBOL_NAME_LEN];

	char padding[LTTNG_EVENT_FUNCTION_PADDING1];
};

/*
 * Generic lttng event
 */
#define LTTNG_EVENT_PADDING1               16
#define LTTNG_EVENT_PADDING2               LTTNG_SYMBOL_NAME_LEN + 32
struct lttng_event {
	enum lttng_event_type type;
	char name[LTTNG_SYMBOL_NAME_LEN];

	enum lttng_loglevel_type loglevel_type;
	int loglevel;

	uint32_t enabled;
	pid_t pid;

	char padding[LTTNG_EVENT_PADDING1];

	/* Per event type configuration */
	union {
		struct lttng_event_probe_attr probe;
		struct lttng_event_function_attr ftrace;

		char padding[LTTNG_EVENT_PADDING2];
	} attr;
};

/*
 * Tracer channel attributes. For both kernel and user-space.
 */
#define LTTNG_CHANNEL_ATTR_PADDING1        LTTNG_SYMBOL_NAME_LEN + 32
struct lttng_channel_attr {
	int overwrite;                      /* 1: overwrite, 0: discard */
	uint64_t subbuf_size;               /* bytes */
	uint64_t num_subbuf;                /* power of 2 */
	unsigned int switch_timer_interval; /* usec */
	unsigned int read_timer_interval;   /* usec */
	enum lttng_event_output output;     /* splice, mmap */

	char padding[LTTNG_CHANNEL_ATTR_PADDING1];
};

/*
 * Channel information structure. For both kernel and user-space.
 */
#define LTTNG_CHANNEL_PADDING1             16
struct lttng_channel {
	char name[LTTNG_SYMBOL_NAME_LEN];
	uint32_t enabled;
	struct lttng_channel_attr attr;

	char padding[LTTNG_CHANNEL_PADDING1];
};

#define LTTNG_CALIBRATE_PADDING1           16
struct lttng_calibrate {
	enum lttng_calibrate_type type;

	char padding[LTTNG_CALIBRATE_PADDING1];
};

/*
 * Basic session information.
 *
 * This is an 'output data' meaning that it only comes *from* the session
 * daemon *to* the lttng client. It's basically a 'human' representation of
 * tracing entities (here a session).
 */
#define LTTNG_SESSION_PADDING1             16
struct lttng_session {
	char name[NAME_MAX];
	/* The path where traces are written */
	char path[PATH_MAX];
	uint32_t enabled;	/* enabled/started: 1, disabled/stopped: 0 */

	char padding[LTTNG_SESSION_PADDING1];
};

/*
 * Handle used as a context for commands.
 */
#define LTTNG_HANDLE_PADDING1              16
struct lttng_handle {
	char session_name[NAME_MAX];
	struct lttng_domain domain;

	char padding[LTTNG_HANDLE_PADDING1];
};

/*
 * Public LTTng control API
 *
 * For functions having an lttng domain type as parameter, if a bad value is
 * given, NO default is applied and an error is returned.
 *
 * On success, all functions of the API return 0 or the size of the allocated
 * array (in bytes).
 *
 * On error, a negative value is returned being a specific lttng-tools error
 * code which can be humanly interpreted with lttng_strerror(err).
 *
 * Exceptions to this are noted below.
 */

/*
 * Create a handle used as a context for every request made to the library.
 *
 * This handle contains the session name and lttng domain on which the command
 * will be executed.
 * The returned pointer will be NULL in case of malloc() error.
 */
extern struct lttng_handle *lttng_create_handle(const char *session_name,
		struct lttng_domain *domain);

/*
 * Destroy a handle. This will simply free(3) the data pointer returned by
 * lttng_create_handle(), rendering it unusable.
 */
extern void lttng_destroy_handle(struct lttng_handle *handle);

/*
 * Create a tracing session using a name and a path where the trace will be
 * written.
 */
extern int lttng_create_session(const char *name, const char *path);

/*
 * Destroy a tracing session.
 *
 * The session will not be usable anymore, tracing will be stopped for all
 * registered traces, and the tracing buffers will be flushed.
 */
extern int lttng_destroy_session(const char *name);

/*
 * List all the tracing sessions.
 *
 * Return the size (number of entries) of the "lttng_session" array. Caller
 * must free(3).
 */
extern int lttng_list_sessions(struct lttng_session **sessions);

/*
 * List the registered domain(s) of a session.
 *
 * Return the size (number of entries) of the "lttng_domain" array. Caller
 * must free(3).
 */
extern int lttng_list_domains(const char *session_name,
		struct lttng_domain **domains);

/*
 * List the channel(s) of a session.
 *
 * Return the size (number of entries) of the "lttng_channel" array. Caller
 * must free(3).
 */
extern int lttng_list_channels(struct lttng_handle *handle,
		struct lttng_channel **channels);

/*
 * List the event(s) of a session channel.
 *
 * Return the size (number of entries) of the "lttng_event" array.
 * Caller must free(3).
 */
extern int lttng_list_events(struct lttng_handle *handle,
		const char *channel_name, struct lttng_event **events);

/*
 * List the available tracepoints of a specific lttng domain.
 *
 * Return the size (number of entries) of the "lttng_event" array.
 * Caller must free(3).
 */
extern int lttng_list_tracepoints(struct lttng_handle *handle,
		struct lttng_event **events);

/*
 * Check if a session daemon is alive.
 *
 * Return 1 if alive or 0 if not. On error returns a negative value.
 */
extern int lttng_session_daemon_alive(void);

/*
 * Set the tracing group for the *current* flow of execution.
 *
 * On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
 */
extern int lttng_set_tracing_group(const char *name);

/*
 * Return a human-readable error message for an lttng-tools error code.
 *
 * Parameter MUST be a negative value or else you'll get a generic message.
 */
extern const char *lttng_strerror(int code);

/*
 * This call registers an "outside consumer" for a session and an lttng domain.
 * No consumer will be spawned and all fds/commands will go through the socket
 * path given (socket_path).
 *
 * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
 * command socket. The error socket is not supported yet for roaming consumers.
 */
extern int lttng_register_consumer(struct lttng_handle *handle,
		const char *socket_path);

/*
 * Start tracing for *all* registered traces (kernel and user-space).
 */
extern int lttng_start_tracing(const char *session_name);

/*
 * Stop tracing for *all* registered traces (kernel and user-space).
 */
extern int lttng_stop_tracing(const char *session_name);

/*
 * Add context to event(s) for a specific channel (or for all).
 *
 * If event_name is NULL, the context is applied to all events of the channel.
 * If channel_name is NULL, a lookup of the event's channel is done.
 * If both are NULL, the context is applied to all events of all channels.
 */
extern int lttng_add_context(struct lttng_handle *handle,
		struct lttng_event_context *ctx, const char *event_name,
		const char *channel_name);

/*
 * Create or enable a kernel event (or events) for a channel.
 *
 * If the event you are trying to enable does not exist, it will be created,
 * else it is enabled.
 * If event_name is NULL, all events are enabled.
 * If channel_name is NULL, the default channel is used (channel0).
 */
extern int lttng_enable_event(struct lttng_handle *handle,
		struct lttng_event *ev, const char *channel_name);

/*
 * Create or enable a kernel channel.
 * The channel name cannot be NULL.
 */
extern int lttng_enable_channel(struct lttng_handle *handle,
		struct lttng_channel *chan);

/*
 * Disable kernel event(s) of a channel and domain.
 *
 * If event_name is NULL, all events are disabled.
 * If channel_name is NULL, the default channel is used (channel0).
 */
extern int lttng_disable_event(struct lttng_handle *handle,
		const char *name, const char *channel_name);

/*
 * Disable kernel channel.
 *
 * The channel name cannot be NULL.
 */
extern int lttng_disable_channel(struct lttng_handle *handle,
		const char *name);

/*
 * Calibrate LTTng overhead.
 */
extern int lttng_calibrate(struct lttng_handle *handle,
		struct lttng_calibrate *calibrate);

/*
 * Set the default channel attributes for a specific domain and an allocated
 * lttng_channel_attr pointer.
 *
 * If either or both of the arguments are NULL, nothing happens.
 */
extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
		struct lttng_channel_attr *attr);

#endif /* _LTTNG_H */
Commit	Line	Data
	1	/*
	2	* lttng.h
	3	*
	4	* Linux Trace Toolkit Control Library Header File
	5	*
	6	* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
	7	*
	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.
	11	*
	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
	15	* for more details.
	16	*
	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
	20	*/
	21
	22	#ifndef _LTTNG_H
	23	#define _LTTNG_H
	24
	25	#include <limits.h>
	26	#include <stdint.h>
	27	#include <sys/types.h>
	28
	29	/*
	30	* Event symbol length. Copied from LTTng kernel ABI.
	31	*/
	32	#define LTTNG_SYMBOL_NAME_LEN 256
	33
	34	/*
	35	* Every lttng_event_* structure both apply to kernel event and user-space
	36	* event.
	37	*/
	38
	39	/*
	40	* Domain types: the different possible tracers.
	41	*/
	42	enum lttng_domain_type {
	43	LTTNG_DOMAIN_KERNEL = 1,
	44	LTTNG_DOMAIN_UST = 2,
	45
	46	/*
	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.
	50	*
	51	LTTNG_DOMAIN_UST_EXEC_NAME = 3,
	52	LTTNG_DOMAIN_UST_PID = 4,
	53	LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN = 5,
	54	*/
	55	};
	56
	57	/*
	58	* Instrumentation type of tracing event.
	59	*/
	60	enum lttng_event_type {
	61	LTTNG_EVENT_ALL = -1,
	62	LTTNG_EVENT_TRACEPOINT = 0,
	63	LTTNG_EVENT_PROBE = 1,
	64	LTTNG_EVENT_FUNCTION = 2,
	65	LTTNG_EVENT_FUNCTION_ENTRY = 3,
	66	LTTNG_EVENT_NOOP = 4,
	67	LTTNG_EVENT_SYSCALL = 5,
	68	};
	69
	70	/*
	71	* Loglevel information.
	72	*/
	73	enum lttng_loglevel_type {
	74	LTTNG_EVENT_LOGLEVEL_ALL = 0,
	75	LTTNG_EVENT_LOGLEVEL_RANGE = 1,
	76	LTTNG_EVENT_LOGLEVEL_SINGLE = 2,
	77	};
	78
	79	/*
	80	* Available loglevels.
	81	*/
	82	enum lttng_loglevel {
	83	LTTNG_LOGLEVEL_EMERG = 0,
	84	LTTNG_LOGLEVEL_ALERT = 1,
	85	LTTNG_LOGLEVEL_CRIT = 2,
	86	LTTNG_LOGLEVEL_ERR = 3,
	87	LTTNG_LOGLEVEL_WARNING = 4,
	88	LTTNG_LOGLEVEL_NOTICE = 5,
	89	LTTNG_LOGLEVEL_INFO = 6,
	90	LTTNG_LOGLEVEL_DEBUG_SYSTEM = 7,
	91	LTTNG_LOGLEVEL_DEBUG_PROGRAM = 8,
	92	LTTNG_LOGLEVEL_DEBUG_PROCESS = 9,
	93	LTTNG_LOGLEVEL_DEBUG_MODULE = 10,
	94	LTTNG_LOGLEVEL_DEBUG_UNIT = 11,
	95	LTTNG_LOGLEVEL_DEBUG_FUNCTION = 12,
	96	LTTNG_LOGLEVEL_DEBUG_LINE = 13,
	97	LTTNG_LOGLEVEL_DEBUG = 14,
	98	};
	99
	100	/*
	101	* LTTng consumer mode
	102	*/
	103	enum lttng_event_output {
	104	LTTNG_EVENT_SPLICE = 0,
	105	LTTNG_EVENT_MMAP = 1,
	106	};
	107
	108	/* Event context possible type */
	109	enum lttng_event_context_type {
	110	LTTNG_EVENT_CONTEXT_PID = 0,
	111	LTTNG_EVENT_CONTEXT_PERF_COUNTER = 1,
	112	LTTNG_EVENT_CONTEXT_PROCNAME = 2,
	113	LTTNG_EVENT_CONTEXT_PRIO = 3,
	114	LTTNG_EVENT_CONTEXT_NICE = 4,
	115	LTTNG_EVENT_CONTEXT_VPID = 5,
	116	LTTNG_EVENT_CONTEXT_TID = 6,
	117	LTTNG_EVENT_CONTEXT_VTID = 7,
	118	LTTNG_EVENT_CONTEXT_PPID = 8,
	119	LTTNG_EVENT_CONTEXT_VPPID = 9,
	120	LTTNG_EVENT_CONTEXT_PTHREAD_ID = 10,
	121	};
	122
	123	enum lttng_calibrate_type {
	124	LTTNG_CALIBRATE_FUNCTION = 0,
	125	};
	126
	127	#define LTTNG_DOMAIN_PADDING1 16
	128	#define LTTNG_DOMAIN_PADDING2 LTTNG_SYMBOL_NAME_LEN + 32
	129	struct lttng_domain {
	130	enum lttng_domain_type type;
	131	char padding[LTTNG_DOMAIN_PADDING1];
	132
	133	union {
	134	pid_t pid;
	135	char exec_name[NAME_MAX];
	136	char padding[LTTNG_DOMAIN_PADDING2];
	137	} attr;
	138	};
	139
	140	/* Perf counter attributes */
	141	#define LTTNG_PERF_EVENT_PADDING1 16
	142	struct lttng_event_perf_counter_ctx {
	143	uint32_t type;
	144	uint64_t config;
	145	char name[LTTNG_SYMBOL_NAME_LEN];
	146
	147	char padding[LTTNG_PERF_EVENT_PADDING1];
	148	};
	149
	150	/* Event/Channel context */
	151	#define LTTNG_EVENT_CONTEXT_PADDING1 16
	152	#define LTTNG_EVENT_CONTEXT_PADDING2 LTTNG_SYMBOL_NAME_LEN + 32
	153	struct lttng_event_context {
	154	enum lttng_event_context_type ctx;
	155	char padding[LTTNG_EVENT_CONTEXT_PADDING1];
	156
	157	union {
	158	struct lttng_event_perf_counter_ctx perf_counter;
	159	char padding[LTTNG_EVENT_CONTEXT_PADDING2];
	160	} u;
	161	};
	162
	163	/*
	164	* Event probe.
	165	*
	166	* Either addr is used or symbol_name and offset.
	167	*/
	168	#define LTTNG_EVENT_PROBE_PADDING1 16
	169	struct lttng_event_probe_attr {
	170	uint64_t addr;
	171
	172	uint64_t offset;
	173	char symbol_name[LTTNG_SYMBOL_NAME_LEN];
	174
	175	char padding[LTTNG_EVENT_PROBE_PADDING1];
	176	};
	177
	178	/*
	179	* Function tracer
	180	*/
	181	#define LTTNG_EVENT_FUNCTION_PADDING1 16
	182	struct lttng_event_function_attr {
	183	char symbol_name[LTTNG_SYMBOL_NAME_LEN];
	184
	185	char padding[LTTNG_EVENT_FUNCTION_PADDING1];
	186	};
	187
	188	/*
	189	* Generic lttng event
	190	*/
	191	#define LTTNG_EVENT_PADDING1 16
	192	#define LTTNG_EVENT_PADDING2 LTTNG_SYMBOL_NAME_LEN + 32
	193	struct lttng_event {
	194	enum lttng_event_type type;
	195	char name[LTTNG_SYMBOL_NAME_LEN];
	196
	197	enum lttng_loglevel_type loglevel_type;
	198	int loglevel;
	199
	200	uint32_t enabled;
	201	pid_t pid;
	202
	203	char padding[LTTNG_EVENT_PADDING1];
	204
	205	/* Per event type configuration */
	206	union {
	207	struct lttng_event_probe_attr probe;
	208	struct lttng_event_function_attr ftrace;
	209
	210	char padding[LTTNG_EVENT_PADDING2];
	211	} attr;
	212	};
	213
	214	/*
	215	* Tracer channel attributes. For both kernel and user-space.
	216	*/
	217	#define LTTNG_CHANNEL_ATTR_PADDING1 LTTNG_SYMBOL_NAME_LEN + 32
	218	struct lttng_channel_attr {
	219	int overwrite; /* 1: overwrite, 0: discard */
	220	uint64_t subbuf_size; /* bytes */
	221	uint64_t num_subbuf; /* power of 2 */
	222	unsigned int switch_timer_interval; /* usec */
	223	unsigned int read_timer_interval; /* usec */
	224	enum lttng_event_output output; /* splice, mmap */
	225
	226	char padding[LTTNG_CHANNEL_ATTR_PADDING1];
	227	};
	228
	229	/*
	230	* Channel information structure. For both kernel and user-space.
	231	*/
	232	#define LTTNG_CHANNEL_PADDING1 16
	233	struct lttng_channel {
	234	char name[LTTNG_SYMBOL_NAME_LEN];
	235	uint32_t enabled;
	236	struct lttng_channel_attr attr;
	237
	238	char padding[LTTNG_CHANNEL_PADDING1];
	239	};
	240
	241	#define LTTNG_CALIBRATE_PADDING1 16
	242	struct lttng_calibrate {
	243	enum lttng_calibrate_type type;
	244
	245	char padding[LTTNG_CALIBRATE_PADDING1];
	246	};
	247
	248	/*
	249	* Basic session information.
	250	*
	251	* This is an 'output data' meaning that it only comes from the session
	252	* daemon to the lttng client. It's basically a 'human' representation of
	253	* tracing entities (here a session).
	254	*/
	255	#define LTTNG_SESSION_PADDING1 16
	256	struct lttng_session {
	257	char name[NAME_MAX];
	258	/* The path where traces are written */
	259	char path[PATH_MAX];
	260	uint32_t enabled; /* enabled/started: 1, disabled/stopped: 0 */
	261
	262	char padding[LTTNG_SESSION_PADDING1];
	263	};
	264
	265	/*
	266	* Handle used as a context for commands.
	267	*/
	268	#define LTTNG_HANDLE_PADDING1 16
	269	struct lttng_handle {
	270	char session_name[NAME_MAX];
	271	struct lttng_domain domain;
	272
	273	char padding[LTTNG_HANDLE_PADDING1];
	274	};
	275
	276	/*
	277	* Public LTTng control API
	278	*
	279	* For functions having an lttng domain type as parameter, if a bad value is
	280	* given, NO default is applied and an error is returned.
	281	*
	282	* On success, all functions of the API return 0 or the size of the allocated
	283	* array (in bytes).
	284	*
	285	* On error, a negative value is returned being a specific lttng-tools error
	286	* code which can be humanly interpreted with lttng_strerror(err).
	287	*
	288	* Exceptions to this are noted below.
	289	*/
	290
	291	/*
	292	* Create a handle used as a context for every request made to the library.
	293	*
	294	* This handle contains the session name and lttng domain on which the command
	295	* will be executed.
	296	* The returned pointer will be NULL in case of malloc() error.
	297	*/
	298	extern struct lttng_handle lttng_create_handle(const char session_name,
	299	struct lttng_domain *domain);
	300
	301	/*
	302	* Destroy a handle. This will simply free(3) the data pointer returned by
	303	* lttng_create_handle(), rendering it unusable.
	304	*/
	305	extern void lttng_destroy_handle(struct lttng_handle *handle);
	306
	307	/*
	308	* Create a tracing session using a name and a path where the trace will be
	309	* written.
	310	*/
	311	extern int lttng_create_session(const char name, const char path);
	312
	313	/*
	314	* Destroy a tracing session.
	315	*
	316	* The session will not be usable anymore, tracing will be stopped for all
	317	* registered traces, and the tracing buffers will be flushed.
	318	*/
	319	extern int lttng_destroy_session(const char *name);
	320
	321	/*
	322	* List all the tracing sessions.
	323	*
	324	* Return the size (number of entries) of the "lttng_session" array. Caller
	325	* must free(3).
	326	*/
	327	extern int lttng_list_sessions(struct lttng_session **sessions);
	328
	329	/*
	330	* List the registered domain(s) of a session.
	331	*
	332	* Return the size (number of entries) of the "lttng_domain" array. Caller
	333	* must free(3).
	334	*/
	335	extern int lttng_list_domains(const char *session_name,
	336	struct lttng_domain **domains);
	337
	338	/*
	339	* List the channel(s) of a session.
	340	*
	341	* Return the size (number of entries) of the "lttng_channel" array. Caller
	342	* must free(3).
	343	*/
	344	extern int lttng_list_channels(struct lttng_handle *handle,
	345	struct lttng_channel **channels);
	346
	347	/*
	348	* List the event(s) of a session channel.
	349	*
	350	* Return the size (number of entries) of the "lttng_event" array.
	351	* Caller must free(3).
	352	*/
	353	extern int lttng_list_events(struct lttng_handle *handle,
	354	const char channel_name, struct lttng_event *events);
	355
	356	/*
	357	* List the available tracepoints of a specific lttng domain.
	358	*
	359	* Return the size (number of entries) of the "lttng_event" array.
	360	* Caller must free(3).
	361	*/
	362	extern int lttng_list_tracepoints(struct lttng_handle *handle,
	363	struct lttng_event **events);
	364
	365	/*
	366	* Check if a session daemon is alive.
	367	*
	368	* Return 1 if alive or 0 if not. On error returns a negative value.
	369	*/
	370	extern int lttng_session_daemon_alive(void);
	371
	372	/*
	373	* Set the tracing group for the current flow of execution.
	374	*
	375	* On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
	376	*/
	377	extern int lttng_set_tracing_group(const char *name);
	378
	379	/*
	380	* Return a human-readable error message for an lttng-tools error code.
	381	*
	382	* Parameter MUST be a negative value or else you'll get a generic message.
	383	*/
	384	extern const char *lttng_strerror(int code);
	385
	386	/*
	387	* This call registers an "outside consumer" for a session and an lttng domain.
	388	* No consumer will be spawned and all fds/commands will go through the socket
	389	* path given (socket_path).
	390	*
	391	* NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
	392	* command socket. The error socket is not supported yet for roaming consumers.
	393	*/
	394	extern int lttng_register_consumer(struct lttng_handle *handle,
	395	const char *socket_path);
	396
	397	/*
	398	* Start tracing for all registered traces (kernel and user-space).
	399	*/
	400	extern int lttng_start_tracing(const char *session_name);
	401
	402	/*
	403	* Stop tracing for all registered traces (kernel and user-space).
	404	*/
	405	extern int lttng_stop_tracing(const char *session_name);
	406
	407	/*
	408	* Add context to event(s) for a specific channel (or for all).
	409	*
	410	* If event_name is NULL, the context is applied to all events of the channel.
	411	* If channel_name is NULL, a lookup of the event's channel is done.
	412	* If both are NULL, the context is applied to all events of all channels.
	413	*/
	414	extern int lttng_add_context(struct lttng_handle *handle,
	415	struct lttng_event_context ctx, const char event_name,
	416	const char *channel_name);
	417
	418	/*
	419	* Create or enable a kernel event (or events) for a channel.
	420	*
	421	* If the event you are trying to enable does not exist, it will be created,
	422	* else it is enabled.
	423	* If event_name is NULL, all events are enabled.
	424	* If channel_name is NULL, the default channel is used (channel0).
	425	*/
	426	extern int lttng_enable_event(struct lttng_handle *handle,
	427	struct lttng_event ev, const char channel_name);
	428
	429	/*
	430	* Create or enable a kernel channel.
	431	* The channel name cannot be NULL.
	432	*/
	433	extern int lttng_enable_channel(struct lttng_handle *handle,
	434	struct lttng_channel *chan);
	435
	436	/*
	437	* Disable kernel event(s) of a channel and domain.
	438	*
	439	* If event_name is NULL, all events are disabled.
	440	* If channel_name is NULL, the default channel is used (channel0).
	441	*/
	442	extern int lttng_disable_event(struct lttng_handle *handle,
	443	const char name, const char channel_name);
	444
	445	/*
	446	* Disable kernel channel.
	447	*
	448	* The channel name cannot be NULL.
	449	*/
	450	extern int lttng_disable_channel(struct lttng_handle *handle,
	451	const char *name);
	452
	453	/*
	454	* Calibrate LTTng overhead.
	455	*/
	456	extern int lttng_calibrate(struct lttng_handle *handle,
	457	struct lttng_calibrate *calibrate);
	458
	459	/*
	460	* Set the default channel attributes for a specific domain and an allocated
	461	* lttng_channel_attr pointer.
	462	*
	463	* If either or both of the arguments are NULL, nothing happens.
	464	*/
	465	extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
	466	struct lttng_channel_attr *attr);
	467
	468	#endif /* _LTTNG_H */