[lttng-ust.git] / include / ust-comm.h

/*
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
 * Copyright (C) 2011 Julien Desfossez <julien.desfossez@polymtl.ca>
 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

/*
 * This header is meant for liblttng and libust internal use ONLY.
 * These declarations should NOT be considered stable API.
 */

#ifndef _LTTNG_UST_COMM_H
#define _LTTNG_UST_COMM_H

#include <stdint.h>
#include <limits.h>
#include <unistd.h>
#include <lttng/ust-abi.h>
#include <lttng/ust-error.h>
#include <lttng/ust-compiler.h>
#include <lttng/ust-ctl.h>
#include "ust-helper.h"

#ifndef LTTNG_PACKED
#error "LTTNG_PACKED should be defined"
#endif

/*
 * Default timeout the application waits for the sessiond to send its
 * "register done" command. Can be overridden with the environment
 * variable "LTTNG_UST_REGISTER_TIMEOUT". Note that if the sessiond is not
 * found, the application proceeds directly without any delay.
 */
#define LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS	CONFIG_LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS

#define LTTNG_DEFAULT_RUNDIR				LTTNG_SYSTEM_RUNDIR
#define LTTNG_DEFAULT_HOME_RUNDIR			".lttng"

/* Queue size of listen(2) */
#define LTTNG_UST_COMM_MAX_LISTEN			10
#define LTTNG_UST_COMM_REG_MSG_PADDING			64

struct lttng_event_field;
struct lttng_ctx_field;
struct lttng_enum_entry;
struct lttng_integer_type;
struct lttng_session;

struct ustctl_reg_msg {
	uint32_t magic;
	uint32_t major;
	uint32_t minor;
	uint32_t pid;
	uint32_t ppid;
	uint32_t uid;
	uint32_t gid;
	uint32_t bits_per_long;
	uint32_t uint8_t_alignment;
	uint32_t uint16_t_alignment;
	uint32_t uint32_t_alignment;
	uint32_t uint64_t_alignment;
	uint32_t long_alignment;
	uint32_t socket_type;			/* enum ustctl_socket_type */
	char name[LTTNG_UST_ABI_PROCNAME_LEN];	/* process name */
	char padding[LTTNG_UST_COMM_REG_MSG_PADDING];
} LTTNG_PACKED;

/*
 * Data structure for the commands sent from sessiond to UST.
 */
#define USTCOMM_MSG_PADDING1		32
#define USTCOMM_MSG_PADDING2		32
struct ustcomm_ust_msg {
	uint32_t handle;
	uint32_t cmd;
	char padding[USTCOMM_MSG_PADDING1];
	union {
		struct lttng_ust_abi_channel channel;
		struct lttng_ust_abi_stream stream;
		struct lttng_ust_abi_event event;
		struct lttng_ust_abi_context context;
		struct lttng_ust_abi_tracer_version version;
		struct lttng_ust_abi_tracepoint_iter tracepoint;
		struct {
			uint32_t data_size;	/* following filter data */
			uint32_t reloc_offset;
			uint64_t seqnum;
		} LTTNG_PACKED filter;
		struct {
			uint32_t count;	/* how many names follow */
		} LTTNG_PACKED exclusion;
		struct {
			uint32_t data_size;	/* following capture data */
			uint32_t reloc_offset;
			uint64_t seqnum;
		} LTTNG_PACKED capture;
		struct lttng_ust_abi_counter counter;
		struct lttng_ust_abi_counter_global counter_global;
		struct lttng_ust_abi_counter_cpu counter_cpu;
		/*
		 * For lttng_ust_abi_EVENT_NOTIFIER_CREATE, a struct
		 * lttng_ust_abi_event_notifier implicitly follows struct
		 * ustcomm_ust_msg.
		 */
		struct {
			/* Length of struct lttng_ust_abi_event_notifier */
			uint32_t len;
		} event_notifier;
		char padding[USTCOMM_MSG_PADDING2];
	} u;
} LTTNG_PACKED;

/*
 * Data structure for the response from UST to the session daemon.
 * cmd_type is sent back in the reply for validation.
 */
#define USTCOMM_REPLY_PADDING1		32
#define USTCOMM_REPLY_PADDING2		32
struct ustcomm_ust_reply {
	uint32_t handle;
	uint32_t cmd;
	int32_t ret_code;	/* enum ustcomm_return_code */
	uint32_t ret_val;	/* return value */
	char padding[USTCOMM_REPLY_PADDING1];
	union {
		struct {
			uint64_t memory_map_size;
		} LTTNG_PACKED channel;
		struct {
			uint64_t memory_map_size;
		} LTTNG_PACKED stream;
		struct lttng_ust_abi_tracer_version version;
		struct lttng_ust_abi_tracepoint_iter tracepoint;
		char padding[USTCOMM_REPLY_PADDING2];
	} u;
} LTTNG_PACKED;

struct ustcomm_notify_hdr {
	uint32_t notify_cmd;
} LTTNG_PACKED;

#define USTCOMM_NOTIFY_EVENT_MSG_PADDING	32
struct ustcomm_notify_event_msg {
	uint32_t session_objd;
	uint32_t channel_objd;
	char event_name[LTTNG_UST_ABI_SYM_NAME_LEN];
	int32_t loglevel;
	uint32_t signature_len;
	uint32_t fields_len;
	uint32_t model_emf_uri_len;
	char padding[USTCOMM_NOTIFY_EVENT_MSG_PADDING];
	/* followed by signature, fields, and model_emf_uri */
} LTTNG_PACKED;

#define USTCOMM_NOTIFY_EVENT_REPLY_PADDING	32
struct ustcomm_notify_event_reply {
	int32_t ret_code;	/* 0: ok, negative: error code */
	uint32_t event_id;
	char padding[USTCOMM_NOTIFY_EVENT_REPLY_PADDING];
} LTTNG_PACKED;

#define USTCOMM_NOTIFY_ENUM_MSG_PADDING		32
struct ustcomm_notify_enum_msg {
	uint32_t session_objd;
	char enum_name[LTTNG_UST_ABI_SYM_NAME_LEN];
	uint32_t entries_len;
	char padding[USTCOMM_NOTIFY_ENUM_MSG_PADDING];
	/* followed by enum entries */
} LTTNG_PACKED;

#define USTCOMM_NOTIFY_EVENT_REPLY_PADDING	32
struct ustcomm_notify_enum_reply {
	int32_t ret_code;	/* 0: ok, negative: error code */
	uint64_t enum_id;
	char padding[USTCOMM_NOTIFY_EVENT_REPLY_PADDING];
} LTTNG_PACKED;

#define USTCOMM_NOTIFY_CHANNEL_MSG_PADDING	32
struct ustcomm_notify_channel_msg {
	uint32_t session_objd;
	uint32_t channel_objd;
	uint32_t ctx_fields_len;
	char padding[USTCOMM_NOTIFY_CHANNEL_MSG_PADDING];
	/* followed by context fields */
} LTTNG_PACKED;

#define USTCOMM_NOTIFY_CHANNEL_REPLY_PADDING	32
struct ustcomm_notify_channel_reply {
	int32_t ret_code;	/* 0: ok, negative: error code */
	uint32_t chan_id;
	uint32_t header_type;	/* enum ustctl_channel_header */
	char padding[USTCOMM_NOTIFY_CHANNEL_REPLY_PADDING];
} LTTNG_PACKED;

/*
 * LTTNG_UST_TRACEPOINT_FIELD_LIST reply is followed by a
 * struct lttng_ust_field_iter field.
 */

LTTNG_HIDDEN
int ustcomm_create_unix_sock(const char *pathname);
LTTNG_HIDDEN
int ustcomm_connect_unix_sock(const char *pathname,
 	long timeout);
LTTNG_HIDDEN
int ustcomm_accept_unix_sock(int sock);
LTTNG_HIDDEN
int ustcomm_listen_unix_sock(int sock);
LTTNG_HIDDEN
int ustcomm_close_unix_sock(int sock);

LTTNG_HIDDEN
ssize_t ustcomm_recv_unix_sock(int sock, void *buf, size_t len);
LTTNG_HIDDEN
ssize_t ustcomm_send_unix_sock(int sock, const void *buf, size_t len);
LTTNG_HIDDEN
ssize_t ustcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd);
LTTNG_HIDDEN
ssize_t ustcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd);

LTTNG_HIDDEN
const char *ustcomm_get_readable_code(int code);
LTTNG_HIDDEN
int ustcomm_send_app_msg(int sock, struct ustcomm_ust_msg *lum);
LTTNG_HIDDEN
int ustcomm_recv_app_reply(int sock, struct ustcomm_ust_reply *lur,
 	uint32_t expected_handle, uint32_t expected_cmd);
LTTNG_HIDDEN
int ustcomm_send_app_cmd(int sock,
		struct ustcomm_ust_msg *lum,
		struct ustcomm_ust_reply *lur);
LTTNG_HIDDEN
int ustcomm_recv_fd(int sock);

LTTNG_HIDDEN
ssize_t ustcomm_recv_channel_from_sessiond(int sock,
		void **chan_data, uint64_t len, int *wakeup_fd);
LTTNG_HIDDEN
int ustcomm_recv_stream_from_sessiond(int sock,
		uint64_t *memory_map_size,
		int *shm_fd, int *wakeup_fd);
LTTNG_HIDDEN
ssize_t ustcomm_recv_event_notifier_notif_fd_from_sessiond(int sock,
		int *event_notifier_notif_fd);

LTTNG_HIDDEN
ssize_t ustcomm_recv_counter_from_sessiond(int sock,
		void **counter_data, uint64_t len);
LTTNG_HIDDEN
int ustcomm_recv_counter_shm_from_sessiond(int sock,
		int *shm_fd);

/*
 * Returns 0 on success, negative error value on error.
 * Returns -EPIPE or -ECONNRESET if other end has hung up.
 */
LTTNG_HIDDEN
int ustcomm_send_reg_msg(int sock,
		enum ustctl_socket_type type,
		uint32_t bits_per_long,
		uint32_t uint8_t_alignment,
		uint32_t uint16_t_alignment,
		uint32_t uint32_t_alignment,
		uint32_t uint64_t_alignment,
		uint32_t long_alignment);

/*
 * Returns 0 on success, negative error value on error.
 * Returns -EPIPE or -ECONNRESET if other end has hung up.
 */
LTTNG_HIDDEN
int ustcomm_register_event(int sock,
	struct lttng_session *session,
	int session_objd,		/* session descriptor */
	int channel_objd,		/* channel descriptor */
	const char *event_name,		/* event name (input) */
	int loglevel,
	const char *signature,		/* event signature (input) */
	size_t nr_fields,		/* fields */
	const struct lttng_event_field *fields,
	const char *model_emf_uri,
	uint32_t *id);			/* event id (output) */

/*
 * Returns 0 on success, negative error value on error.
 * Returns -EPIPE or -ECONNRESET if other end has hung up.
 */
LTTNG_HIDDEN
int ustcomm_register_enum(int sock,
	int session_objd,		/* session descriptor */
	const char *enum_name,		/* enum name (input) */
	size_t nr_entries,		/* entries */
	const struct lttng_enum_entry *entries,
	uint64_t *id);			/* enum id (output) */

/*
 * Returns 0 on success, negative error value on error.
 * Returns -EPIPE or -ECONNRESET if other end has hung up.
 */
LTTNG_HIDDEN
int ustcomm_register_channel(int sock,
	struct lttng_session *session,
	int session_objd,		/* session descriptor */
	int channel_objd,		/* channel descriptor */
	size_t nr_ctx_fields,
	const struct lttng_ctx_field *ctx_fields,
	uint32_t *chan_id,		/* channel id (output) */
	int *header_type); 		/* header type (output) */

LTTNG_HIDDEN
int ustcomm_setsockopt_rcv_timeout(int sock, unsigned int msec);
LTTNG_HIDDEN
int ustcomm_setsockopt_snd_timeout(int sock, unsigned int msec);

#endif	/* _LTTNG_UST_COMM_H */
Commit	Line	Data
	1	/*
	2	* SPDX-License-Identifier: LGPL-2.1-only
	3	*
	4	* Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
	5	* Copyright (C) 2011 Julien Desfossez <julien.desfossez@polymtl.ca>
	6	* Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	7	*/
	8
	9	/*
	10	* This header is meant for liblttng and libust internal use ONLY.
	11	* These declarations should NOT be considered stable API.
	12	*/
	13
	14	#ifndef _LTTNG_UST_COMM_H
	15	#define _LTTNG_UST_COMM_H
	16
	17	#include <stdint.h>
	18	#include <limits.h>
	19	#include <unistd.h>
	20	#include <lttng/ust-abi.h>
	21	#include <lttng/ust-error.h>
	22	#include <lttng/ust-compiler.h>
	23	#include <lttng/ust-ctl.h>
	24	#include "ust-helper.h"
	25
	26	#ifndef LTTNG_PACKED
	27	#error "LTTNG_PACKED should be defined"
	28	#endif
	29
	30	/*
	31	* Default timeout the application waits for the sessiond to send its
	32	* "register done" command. Can be overridden with the environment
	33	* variable "LTTNG_UST_REGISTER_TIMEOUT". Note that if the sessiond is not
	34	* found, the application proceeds directly without any delay.
	35	*/
	36	#define LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS CONFIG_LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS
	37
	38	#define LTTNG_DEFAULT_RUNDIR LTTNG_SYSTEM_RUNDIR
	39	#define LTTNG_DEFAULT_HOME_RUNDIR ".lttng"
	40
	41	/* Queue size of listen(2) */
	42	#define LTTNG_UST_COMM_MAX_LISTEN 10
	43	#define LTTNG_UST_COMM_REG_MSG_PADDING 64
	44
	45	struct lttng_event_field;
	46	struct lttng_ctx_field;
	47	struct lttng_enum_entry;
	48	struct lttng_integer_type;
	49	struct lttng_session;
	50
	51	struct ustctl_reg_msg {
	52	uint32_t magic;
	53	uint32_t major;
	54	uint32_t minor;
	55	uint32_t pid;
	56	uint32_t ppid;
	57	uint32_t uid;
	58	uint32_t gid;
	59	uint32_t bits_per_long;
	60	uint32_t uint8_t_alignment;
	61	uint32_t uint16_t_alignment;
	62	uint32_t uint32_t_alignment;
	63	uint32_t uint64_t_alignment;
	64	uint32_t long_alignment;
	65	uint32_t socket_type; /* enum ustctl_socket_type */
	66	char name[LTTNG_UST_ABI_PROCNAME_LEN]; /* process name */
	67	char padding[LTTNG_UST_COMM_REG_MSG_PADDING];
	68	} LTTNG_PACKED;
	69
	70	/*
	71	* Data structure for the commands sent from sessiond to UST.
	72	*/
	73	#define USTCOMM_MSG_PADDING1 32
	74	#define USTCOMM_MSG_PADDING2 32
	75	struct ustcomm_ust_msg {
	76	uint32_t handle;
	77	uint32_t cmd;
	78	char padding[USTCOMM_MSG_PADDING1];
	79	union {
	80	struct lttng_ust_abi_channel channel;
	81	struct lttng_ust_abi_stream stream;
	82	struct lttng_ust_abi_event event;
	83	struct lttng_ust_abi_context context;
	84	struct lttng_ust_abi_tracer_version version;
	85	struct lttng_ust_abi_tracepoint_iter tracepoint;
	86	struct {
	87	uint32_t data_size; /* following filter data */
	88	uint32_t reloc_offset;
	89	uint64_t seqnum;
	90	} LTTNG_PACKED filter;
	91	struct {
	92	uint32_t count; /* how many names follow */
	93	} LTTNG_PACKED exclusion;
	94	struct {
	95	uint32_t data_size; /* following capture data */
	96	uint32_t reloc_offset;
	97	uint64_t seqnum;
	98	} LTTNG_PACKED capture;
	99	struct lttng_ust_abi_counter counter;
	100	struct lttng_ust_abi_counter_global counter_global;
	101	struct lttng_ust_abi_counter_cpu counter_cpu;
	102	/*
	103	* For lttng_ust_abi_EVENT_NOTIFIER_CREATE, a struct
	104	* lttng_ust_abi_event_notifier implicitly follows struct
	105	* ustcomm_ust_msg.
	106	*/
	107	struct {
	108	/* Length of struct lttng_ust_abi_event_notifier */
	109	uint32_t len;
	110	} event_notifier;
	111	char padding[USTCOMM_MSG_PADDING2];
	112	} u;
	113	} LTTNG_PACKED;
	114
	115	/*
	116	* Data structure for the response from UST to the session daemon.
	117	* cmd_type is sent back in the reply for validation.
	118	*/
	119	#define USTCOMM_REPLY_PADDING1 32
	120	#define USTCOMM_REPLY_PADDING2 32
	121	struct ustcomm_ust_reply {
	122	uint32_t handle;
	123	uint32_t cmd;
	124	int32_t ret_code; /* enum ustcomm_return_code */
	125	uint32_t ret_val; /* return value */
	126	char padding[USTCOMM_REPLY_PADDING1];
	127	union {
	128	struct {
	129	uint64_t memory_map_size;
	130	} LTTNG_PACKED channel;
	131	struct {
	132	uint64_t memory_map_size;
	133	} LTTNG_PACKED stream;
	134	struct lttng_ust_abi_tracer_version version;
	135	struct lttng_ust_abi_tracepoint_iter tracepoint;
	136	char padding[USTCOMM_REPLY_PADDING2];
	137	} u;
	138	} LTTNG_PACKED;
	139
	140	struct ustcomm_notify_hdr {
	141	uint32_t notify_cmd;
	142	} LTTNG_PACKED;
	143
	144	#define USTCOMM_NOTIFY_EVENT_MSG_PADDING 32
	145	struct ustcomm_notify_event_msg {
	146	uint32_t session_objd;
	147	uint32_t channel_objd;
	148	char event_name[LTTNG_UST_ABI_SYM_NAME_LEN];
	149	int32_t loglevel;
	150	uint32_t signature_len;
	151	uint32_t fields_len;
	152	uint32_t model_emf_uri_len;
	153	char padding[USTCOMM_NOTIFY_EVENT_MSG_PADDING];
	154	/* followed by signature, fields, and model_emf_uri */
	155	} LTTNG_PACKED;
	156
	157	#define USTCOMM_NOTIFY_EVENT_REPLY_PADDING 32
	158	struct ustcomm_notify_event_reply {
	159	int32_t ret_code; /* 0: ok, negative: error code */
	160	uint32_t event_id;
	161	char padding[USTCOMM_NOTIFY_EVENT_REPLY_PADDING];
	162	} LTTNG_PACKED;
	163
	164	#define USTCOMM_NOTIFY_ENUM_MSG_PADDING 32
	165	struct ustcomm_notify_enum_msg {
	166	uint32_t session_objd;
	167	char enum_name[LTTNG_UST_ABI_SYM_NAME_LEN];
	168	uint32_t entries_len;
	169	char padding[USTCOMM_NOTIFY_ENUM_MSG_PADDING];
	170	/* followed by enum entries */
	171	} LTTNG_PACKED;
	172
	173	#define USTCOMM_NOTIFY_EVENT_REPLY_PADDING 32
	174	struct ustcomm_notify_enum_reply {
	175	int32_t ret_code; /* 0: ok, negative: error code */
	176	uint64_t enum_id;
	177	char padding[USTCOMM_NOTIFY_EVENT_REPLY_PADDING];
	178	} LTTNG_PACKED;
	179
	180	#define USTCOMM_NOTIFY_CHANNEL_MSG_PADDING 32
	181	struct ustcomm_notify_channel_msg {
	182	uint32_t session_objd;
	183	uint32_t channel_objd;
	184	uint32_t ctx_fields_len;
	185	char padding[USTCOMM_NOTIFY_CHANNEL_MSG_PADDING];
	186	/* followed by context fields */
	187	} LTTNG_PACKED;
	188
	189	#define USTCOMM_NOTIFY_CHANNEL_REPLY_PADDING 32
	190	struct ustcomm_notify_channel_reply {
	191	int32_t ret_code; /* 0: ok, negative: error code */
	192	uint32_t chan_id;
	193	uint32_t header_type; /* enum ustctl_channel_header */
	194	char padding[USTCOMM_NOTIFY_CHANNEL_REPLY_PADDING];
	195	} LTTNG_PACKED;
	196
	197	/*
	198	* LTTNG_UST_TRACEPOINT_FIELD_LIST reply is followed by a
	199	* struct lttng_ust_field_iter field.
	200	*/
	201
	202	LTTNG_HIDDEN
	203	int ustcomm_create_unix_sock(const char *pathname);
	204	LTTNG_HIDDEN
	205	int ustcomm_connect_unix_sock(const char *pathname,
	206	long timeout);
	207	LTTNG_HIDDEN
	208	int ustcomm_accept_unix_sock(int sock);
	209	LTTNG_HIDDEN
	210	int ustcomm_listen_unix_sock(int sock);
	211	LTTNG_HIDDEN
	212	int ustcomm_close_unix_sock(int sock);
	213
	214	LTTNG_HIDDEN
	215	ssize_t ustcomm_recv_unix_sock(int sock, void *buf, size_t len);
	216	LTTNG_HIDDEN
	217	ssize_t ustcomm_send_unix_sock(int sock, const void *buf, size_t len);
	218	LTTNG_HIDDEN
	219	ssize_t ustcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd);
	220	LTTNG_HIDDEN
	221	ssize_t ustcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd);
	222
	223	LTTNG_HIDDEN
	224	const char *ustcomm_get_readable_code(int code);
	225	LTTNG_HIDDEN
	226	int ustcomm_send_app_msg(int sock, struct ustcomm_ust_msg *lum);
	227	LTTNG_HIDDEN
	228	int ustcomm_recv_app_reply(int sock, struct ustcomm_ust_reply *lur,
	229	uint32_t expected_handle, uint32_t expected_cmd);
	230	LTTNG_HIDDEN
	231	int ustcomm_send_app_cmd(int sock,
	232	struct ustcomm_ust_msg *lum,
	233	struct ustcomm_ust_reply *lur);
	234	LTTNG_HIDDEN
	235	int ustcomm_recv_fd(int sock);
	236
	237	LTTNG_HIDDEN
	238	ssize_t ustcomm_recv_channel_from_sessiond(int sock,
	239	void *chan_data, uint64_t len, int wakeup_fd);
	240	LTTNG_HIDDEN
	241	int ustcomm_recv_stream_from_sessiond(int sock,
	242	uint64_t *memory_map_size,
	243	int shm_fd, int wakeup_fd);
	244	LTTNG_HIDDEN
	245	ssize_t ustcomm_recv_event_notifier_notif_fd_from_sessiond(int sock,
	246	int *event_notifier_notif_fd);
	247
	248	LTTNG_HIDDEN
	249	ssize_t ustcomm_recv_counter_from_sessiond(int sock,
	250	void **counter_data, uint64_t len);
	251	LTTNG_HIDDEN
	252	int ustcomm_recv_counter_shm_from_sessiond(int sock,
	253	int *shm_fd);
	254
	255	/*
	256	* Returns 0 on success, negative error value on error.
	257	* Returns -EPIPE or -ECONNRESET if other end has hung up.
	258	*/
	259	LTTNG_HIDDEN
	260	int ustcomm_send_reg_msg(int sock,
	261	enum ustctl_socket_type type,
	262	uint32_t bits_per_long,
	263	uint32_t uint8_t_alignment,
	264	uint32_t uint16_t_alignment,
	265	uint32_t uint32_t_alignment,
	266	uint32_t uint64_t_alignment,
	267	uint32_t long_alignment);
	268
	269	/*
	270	* Returns 0 on success, negative error value on error.
	271	* Returns -EPIPE or -ECONNRESET if other end has hung up.
	272	*/
	273	LTTNG_HIDDEN
	274	int ustcomm_register_event(int sock,
	275	struct lttng_session *session,
	276	int session_objd, /* session descriptor */
	277	int channel_objd, /* channel descriptor */
	278	const char event_name, / event name (input) */
	279	int loglevel,
	280	const char signature, / event signature (input) */
	281	size_t nr_fields, /* fields */
	282	const struct lttng_event_field *fields,
	283	const char *model_emf_uri,
	284	uint32_t id); / event id (output) */
	285
	286	/*
	287	* Returns 0 on success, negative error value on error.
	288	* Returns -EPIPE or -ECONNRESET if other end has hung up.
	289	*/
	290	LTTNG_HIDDEN
	291	int ustcomm_register_enum(int sock,
	292	int session_objd, /* session descriptor */
	293	const char enum_name, / enum name (input) */
	294	size_t nr_entries, /* entries */
	295	const struct lttng_enum_entry *entries,
	296	uint64_t id); / enum id (output) */
	297
	298	/*
	299	* Returns 0 on success, negative error value on error.
	300	* Returns -EPIPE or -ECONNRESET if other end has hung up.
	301	*/
	302	LTTNG_HIDDEN
	303	int ustcomm_register_channel(int sock,
	304	struct lttng_session *session,
	305	int session_objd, /* session descriptor */
	306	int channel_objd, /* channel descriptor */
	307	size_t nr_ctx_fields,
	308	const struct lttng_ctx_field *ctx_fields,
	309	uint32_t chan_id, / channel id (output) */
	310	int header_type); / header type (output) */
	311
	312	LTTNG_HIDDEN
	313	int ustcomm_setsockopt_rcv_timeout(int sock, unsigned int msec);
	314	LTTNG_HIDDEN
	315	int ustcomm_setsockopt_snd_timeout(int sock, unsigned int msec);
	316
	317	#endif /* _LTTNG_UST_COMM_H */