[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, version 2.1 only,
 * as published by the Free Software Foundation.
 *
 * 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,
};

/*
 * The structures should be initialized to zero before use.
 */
#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
 *
 * The structures should be initialized to zero before use.
 */
#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
 *
 * The structures should be initialized to zero before use.
 */
#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.
 *
 * The structures should be initialized to zero before use.
 */
#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
 *
 * The structures should be initialized to zero before use.
 */
#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
 *
 * The structures should be initialized to zero before use.
 */
#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;

	int32_t enabled;	/* Does not apply: -1 */
	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;
};

enum lttng_event_field_type {
	LTTNG_EVENT_FIELD_OTHER			= 0,
	LTTNG_EVENT_FIELD_INTEGER		= 1,
	LTTNG_EVENT_FIELD_ENUM			= 2,
	LTTNG_EVENT_FIELD_FLOAT			= 3,
	LTTNG_EVENT_FIELD_STRING		= 4,
};

#define LTTNG_EVENT_FIELD_PADDING	LTTNG_SYMBOL_NAME_LEN + 32
struct lttng_event_field {
	char field_name[LTTNG_SYMBOL_NAME_LEN];
	enum lttng_event_field_type type;
	char padding[LTTNG_EVENT_FIELD_PADDING];
	struct lttng_event event;
};

/*
 * Tracer channel attributes. For both kernel and user-space.
 *
 * The structures should be initialized to zero before use.
 */
#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.
 *
 * The structures should be initialized to zero before use.
 */
#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).
 *
 * The structures should be initialized to zero before use.
 */
#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.
 *
 * The structures should be initialized to zero before use.
 */
#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);

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

/*
 * 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 an 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 channel.
 * The channel name cannot be NULL.
 */
extern int lttng_enable_channel(struct lttng_handle *handle,
		struct lttng_channel *chan);

/*
 * Disable 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 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, version 2.1 only,
	10	* as published by the Free Software Foundation.
	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	/*
	128	* The structures should be initialized to zero before use.
	129	*/
	130	#define LTTNG_DOMAIN_PADDING1 16
	131	#define LTTNG_DOMAIN_PADDING2 LTTNG_SYMBOL_NAME_LEN + 32
	132	struct lttng_domain {
	133	enum lttng_domain_type type;
	134	char padding[LTTNG_DOMAIN_PADDING1];
	135
	136	union {
	137	pid_t pid;
	138	char exec_name[NAME_MAX];
	139	char padding[LTTNG_DOMAIN_PADDING2];
	140	} attr;
	141	};
	142
	143	/*
	144	* Perf counter attributes
	145	*
	146	* The structures should be initialized to zero before use.
	147	*/
	148	#define LTTNG_PERF_EVENT_PADDING1 16
	149	struct lttng_event_perf_counter_ctx {
	150	uint32_t type;
	151	uint64_t config;
	152	char name[LTTNG_SYMBOL_NAME_LEN];
	153
	154	char padding[LTTNG_PERF_EVENT_PADDING1];
	155	};
	156
	157	/*
	158	* Event/channel context
	159	*
	160	* The structures should be initialized to zero before use.
	161	*/
	162	#define LTTNG_EVENT_CONTEXT_PADDING1 16
	163	#define LTTNG_EVENT_CONTEXT_PADDING2 LTTNG_SYMBOL_NAME_LEN + 32
	164	struct lttng_event_context {
	165	enum lttng_event_context_type ctx;
	166	char padding[LTTNG_EVENT_CONTEXT_PADDING1];
	167
	168	union {
	169	struct lttng_event_perf_counter_ctx perf_counter;
	170	char padding[LTTNG_EVENT_CONTEXT_PADDING2];
	171	} u;
	172	};
	173
	174	/*
	175	* Event probe.
	176	*
	177	* Either addr is used or symbol_name and offset.
	178	*
	179	* The structures should be initialized to zero before use.
	180	*/
	181	#define LTTNG_EVENT_PROBE_PADDING1 16
	182	struct lttng_event_probe_attr {
	183	uint64_t addr;
	184
	185	uint64_t offset;
	186	char symbol_name[LTTNG_SYMBOL_NAME_LEN];
	187
	188	char padding[LTTNG_EVENT_PROBE_PADDING1];
	189	};
	190
	191	/*
	192	* Function tracer
	193	*
	194	* The structures should be initialized to zero before use.
	195	*/
	196	#define LTTNG_EVENT_FUNCTION_PADDING1 16
	197	struct lttng_event_function_attr {
	198	char symbol_name[LTTNG_SYMBOL_NAME_LEN];
	199
	200	char padding[LTTNG_EVENT_FUNCTION_PADDING1];
	201	};
	202
	203	/*
	204	* Generic lttng event
	205	*
	206	* The structures should be initialized to zero before use.
	207	*/
	208	#define LTTNG_EVENT_PADDING1 16
	209	#define LTTNG_EVENT_PADDING2 LTTNG_SYMBOL_NAME_LEN + 32
	210	struct lttng_event {
	211	enum lttng_event_type type;
	212	char name[LTTNG_SYMBOL_NAME_LEN];
	213
	214	enum lttng_loglevel_type loglevel_type;
	215	int loglevel;
	216
	217	int32_t enabled; /* Does not apply: -1 */
	218	pid_t pid;
	219
	220	char padding[LTTNG_EVENT_PADDING1];
	221
	222	/* Per event type configuration */
	223	union {
	224	struct lttng_event_probe_attr probe;
	225	struct lttng_event_function_attr ftrace;
	226
	227	char padding[LTTNG_EVENT_PADDING2];
	228	} attr;
	229	};
	230
	231	enum lttng_event_field_type {
	232	LTTNG_EVENT_FIELD_OTHER = 0,
	233	LTTNG_EVENT_FIELD_INTEGER = 1,
	234	LTTNG_EVENT_FIELD_ENUM = 2,
	235	LTTNG_EVENT_FIELD_FLOAT = 3,
	236	LTTNG_EVENT_FIELD_STRING = 4,
	237	};
	238
	239	#define LTTNG_EVENT_FIELD_PADDING LTTNG_SYMBOL_NAME_LEN + 32
	240	struct lttng_event_field {
	241	char field_name[LTTNG_SYMBOL_NAME_LEN];
	242	enum lttng_event_field_type type;
	243	char padding[LTTNG_EVENT_FIELD_PADDING];
	244	struct lttng_event event;
	245	};
	246
	247	/*
	248	* Tracer channel attributes. For both kernel and user-space.
	249	*
	250	* The structures should be initialized to zero before use.
	251	*/
	252	#define LTTNG_CHANNEL_ATTR_PADDING1 LTTNG_SYMBOL_NAME_LEN + 32
	253	struct lttng_channel_attr {
	254	int overwrite; /* 1: overwrite, 0: discard */
	255	uint64_t subbuf_size; /* bytes */
	256	uint64_t num_subbuf; /* power of 2 */
	257	unsigned int switch_timer_interval; /* usec */
	258	unsigned int read_timer_interval; /* usec */
	259	enum lttng_event_output output; /* splice, mmap */
	260
	261	char padding[LTTNG_CHANNEL_ATTR_PADDING1];
	262	};
	263
	264	/*
	265	* Channel information structure. For both kernel and user-space.
	266	*
	267	* The structures should be initialized to zero before use.
	268	*/
	269	#define LTTNG_CHANNEL_PADDING1 16
	270	struct lttng_channel {
	271	char name[LTTNG_SYMBOL_NAME_LEN];
	272	uint32_t enabled;
	273	struct lttng_channel_attr attr;
	274
	275	char padding[LTTNG_CHANNEL_PADDING1];
	276	};
	277
	278	#define LTTNG_CALIBRATE_PADDING1 16
	279	struct lttng_calibrate {
	280	enum lttng_calibrate_type type;
	281
	282	char padding[LTTNG_CALIBRATE_PADDING1];
	283	};
	284
	285	/*
	286	* Basic session information.
	287	*
	288	* This is an 'output data' meaning that it only comes from the session
	289	* daemon to the lttng client. It's basically a 'human' representation of
	290	* tracing entities (here a session).
	291	*
	292	* The structures should be initialized to zero before use.
	293	*/
	294	#define LTTNG_SESSION_PADDING1 16
	295	struct lttng_session {
	296	char name[NAME_MAX];
	297	/* The path where traces are written */
	298	char path[PATH_MAX];
	299	uint32_t enabled; /* enabled/started: 1, disabled/stopped: 0 */
	300
	301	char padding[LTTNG_SESSION_PADDING1];
	302	};
	303
	304	/*
	305	* Handle used as a context for commands.
	306	*
	307	* The structures should be initialized to zero before use.
	308	*/
	309	#define LTTNG_HANDLE_PADDING1 16
	310	struct lttng_handle {
	311	char session_name[NAME_MAX];
	312	struct lttng_domain domain;
	313
	314	char padding[LTTNG_HANDLE_PADDING1];
	315	};
	316
	317	/*
	318	* Public LTTng control API
	319	*
	320	* For functions having an lttng domain type as parameter, if a bad value is
	321	* given, NO default is applied and an error is returned.
	322	*
	323	* On success, all functions of the API return 0 or the size of the allocated
	324	* array (in bytes).
	325	*
	326	* On error, a negative value is returned being a specific lttng-tools error
	327	* code which can be humanly interpreted with lttng_strerror(err).
	328	*
	329	* Exceptions to this are noted below.
	330	*/
	331
	332	/*
	333	* Create a handle used as a context for every request made to the library.
	334	*
	335	* This handle contains the session name and lttng domain on which the command
	336	* will be executed.
	337	* The returned pointer will be NULL in case of malloc() error.
	338	*/
	339	extern struct lttng_handle lttng_create_handle(const char session_name,
	340	struct lttng_domain *domain);
	341
	342	/*
	343	* Destroy a handle. This will simply free(3) the data pointer returned by
	344	* lttng_create_handle(), rendering it unusable.
	345	*/
	346	extern void lttng_destroy_handle(struct lttng_handle *handle);
	347
	348	/*
	349	* Create a tracing session using a name and a path where the trace will be
	350	* written.
	351	*/
	352	extern int lttng_create_session(const char name, const char path);
	353
	354	/*
	355	* Destroy a tracing session.
	356	*
	357	* The session will not be usable anymore, tracing will be stopped for all
	358	* registered traces, and the tracing buffers will be flushed.
	359	*/
	360	extern int lttng_destroy_session(const char *name);
	361
	362	/*
	363	* List all the tracing sessions.
	364	*
	365	* Return the size (number of entries) of the "lttng_session" array. Caller
	366	* must free(3).
	367	*/
	368	extern int lttng_list_sessions(struct lttng_session **sessions);
	369
	370	/*
	371	* List the registered domain(s) of a session.
	372	*
	373	* Return the size (number of entries) of the "lttng_domain" array. Caller
	374	* must free(3).
	375	*/
	376	extern int lttng_list_domains(const char *session_name,
	377	struct lttng_domain **domains);
	378
	379	/*
	380	* List the channel(s) of a session.
	381	*
	382	* Return the size (number of entries) of the "lttng_channel" array. Caller
	383	* must free(3).
	384	*/
	385	extern int lttng_list_channels(struct lttng_handle *handle,
	386	struct lttng_channel **channels);
	387
	388	/*
	389	* List the event(s) of a session channel.
	390	*
	391	* Return the size (number of entries) of the "lttng_event" array.
	392	* Caller must free(3).
	393	*/
	394	extern int lttng_list_events(struct lttng_handle *handle,
	395	const char channel_name, struct lttng_event *events);
	396
	397	/*
	398	* List the available tracepoints of a specific lttng domain.
	399	*
	400	* Return the size (number of entries) of the "lttng_event" array.
	401	* Caller must free(3).
	402	*/
	403	extern int lttng_list_tracepoints(struct lttng_handle *handle,
	404	struct lttng_event **events);
	405
	406	/*
	407	* List the available tracepoints fields of a specific lttng domain.
	408	*
	409	* Return the size (number of entries) of the "lttng_event_field" array.
	410	* Caller must free(3).
	411	*/
	412	extern int lttng_list_tracepoint_fields(struct lttng_handle *handle,
	413	struct lttng_event_field **fields);
	414
	415	/*
	416	* Check if a session daemon is alive.
	417	*
	418	* Return 1 if alive or 0 if not. On error returns a negative value.
	419	*/
	420	extern int lttng_session_daemon_alive(void);
	421
	422	/*
	423	* Set the tracing group for the current flow of execution.
	424	*
	425	* On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
	426	*/
	427	extern int lttng_set_tracing_group(const char *name);
	428
	429	/*
	430	* Return a human-readable error message for an lttng-tools error code.
	431	*
	432	* Parameter MUST be a negative value or else you'll get a generic message.
	433	*/
	434	extern const char *lttng_strerror(int code);
	435
	436	/*
	437	* This call registers an "outside consumer" for a session and an lttng domain.
	438	* No consumer will be spawned and all fds/commands will go through the socket
	439	* path given (socket_path).
	440	*
	441	* NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
	442	* command socket. The error socket is not supported yet for roaming consumers.
	443	*/
	444	extern int lttng_register_consumer(struct lttng_handle *handle,
	445	const char *socket_path);
	446
	447	/*
	448	* Start tracing for all registered traces (kernel and user-space).
	449	*/
	450	extern int lttng_start_tracing(const char *session_name);
	451
	452	/*
	453	* Stop tracing for all registered traces (kernel and user-space).
	454	*/
	455	extern int lttng_stop_tracing(const char *session_name);
	456
	457	/*
	458	* Add context to event(s) for a specific channel (or for all).
	459	*
	460	* If event_name is NULL, the context is applied to all events of the channel.
	461	* If channel_name is NULL, a lookup of the event's channel is done.
	462	* If both are NULL, the context is applied to all events of all channels.
	463	*/
	464	extern int lttng_add_context(struct lttng_handle *handle,
	465	struct lttng_event_context ctx, const char event_name,
	466	const char *channel_name);
	467
	468	/*
	469	* Create or enable an event (or events) for a channel.
	470	*
	471	* If the event you are trying to enable does not exist, it will be created,
	472	* else it is enabled.
	473	* If event_name is NULL, all events are enabled.
	474	* If channel_name is NULL, the default channel is used (channel0).
	475	*/
	476	extern int lttng_enable_event(struct lttng_handle *handle,
	477	struct lttng_event ev, const char channel_name);
	478
	479	/*
	480	* Create or enable a channel.
	481	* The channel name cannot be NULL.
	482	*/
	483	extern int lttng_enable_channel(struct lttng_handle *handle,
	484	struct lttng_channel *chan);
	485
	486	/*
	487	* Disable event(s) of a channel and domain.
	488	*
	489	* If event_name is NULL, all events are disabled.
	490	* If channel_name is NULL, the default channel is used (channel0).
	491	*/
	492	extern int lttng_disable_event(struct lttng_handle *handle,
	493	const char name, const char channel_name);
	494
	495	/*
	496	* Disable channel.
	497	*
	498	* The channel name cannot be NULL.
	499	*/
	500	extern int lttng_disable_channel(struct lttng_handle *handle,
	501	const char *name);
	502
	503	/*
	504	* Calibrate LTTng overhead.
	505	*/
	506	extern int lttng_calibrate(struct lttng_handle *handle,
	507	struct lttng_calibrate *calibrate);
	508
	509	/*
	510	* Set the default channel attributes for a specific domain and an allocated
	511	* lttng_channel_attr pointer.
	512	*
	513	* If either or both of the arguments are NULL, nothing happens.
	514	*/
	515	extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
	516	struct lttng_channel_attr *attr);
	517
	518	#endif /* _LTTNG_H */