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

/*
 * Copyright (C) 2014 - David Goulet <dgoulet@efficios.com>
 * Copyright (C) 2019 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * 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_SESSION_H
#define LTTNG_SESSION_H

#ifdef __cplusplus
extern "C" {
#endif

struct lttng_session_descriptor;
struct lttng_destruction_handle;

/*
 * Basic session information.
 *
 * The "enabled" field is only used when listing the sessions which indicate if
 * it's started or not.
 *
 * The structures should be initialized to zero before use.
 */
#define LTTNG_SESSION_PADDING1             8
struct lttng_session {
	char name[LTTNG_NAME_MAX];
	/*
	 * Human-readable representation of the trace's destination.
	 * In the case of a local tracing session, a path is provided:
	 *     /path/to/the/output
	 *
	 * In the case of a remote (network) tracing session, the string has
	 * the following format:
	 *     net://hostname/path:ctrl_port [data: data_port]
	 */
	char path[PATH_MAX];
	uint32_t enabled;	/* enabled/started: 1, disabled/stopped: 0 */
	uint32_t snapshot_mode;
	unsigned int live_timer_interval;	/* usec */

	/*
	 * End of public attributes.
	 * The remaining fields are used to deal with ABI management concerns.
	 */

	/*
	 * 32-bit architectures are already naturally aligned on 4 bytes after
	 * 'live_timer_interval'. However, the offset does not result in a
	 * natural alignment on 64-bit architectures. Adding 4 bytes of
	 * padding here results in an aligned offset after 'alignement_padding'
	 * for both bitnesses.
	 *
	 * This was added since not all compilers appear to align unions in the
	 * same way. Some (e.g. MSVC) do not seem to impose an alignement
	 * constraint while others (e.g. gcc, clang, icc) seem to align it to
	 * ensure 'ptr' is naturally aligned.
	 */
	char alignment_padding[4];
	union {
		/*
		 * Ensure the 'extended' union has the same size for both
		 * 32-bit and 64-bit builds.
		 */
		char padding[LTTNG_SESSION_PADDING1];
		void *ptr;
	} extended;
};

/*
 * Create a session on the session daemon from a session descriptor.
 *
 * See the session descriptor API description in session-descriptor.h
 *
 * Note that unspecified session descriptor parameters, such as a session's
 * name, are updated in the session descriptor if the creation of the session
 * succeeds. This allows users to query the session's auto-generated name
 * after its creation. Note that other attributes can be queried using the
 * session listing API.
 *
 * Returns LTTNG_OK on success. See lttng-error.h for the meaning of the other
 * return codes.
 */
extern enum lttng_error_code lttng_create_session_ext(
		struct lttng_session_descriptor *session_descriptor);

/*
 * Create a tracing session using a name and an optional URL.
 *
 * If _url_ is NULL, no consumer is created for the session. The name can't be
 * NULL here.
 *
 * Return 0 on success else a negative LTTng error code.
 */
extern int lttng_create_session(const char *name, const char *url);

/*
 * Create a tracing session that will exclusively be used for snapshot meaning
 * the session will be in no output mode and every channel enabled for that
 * session will be set in overwrite mode and in mmap output since splice is not
 * supported.
 *
 * Name can't be NULL. If an url is given, it will be used to create a default
 * snapshot output using it as a destination. If NULL, no output will be
 * defined and an add-output call will be needed.
 *
 * Return 0 on success else a negative LTTng error code.
 */
extern int lttng_create_session_snapshot(const char *name,
		const char *snapshot_url);

/*
 * Create a session exclusively used for live reading.
 *
 * In this mode, the switch-timer parameter is forced for each UST channel, a
 * live-switch-timer is enabled for kernel channels, manually setting
 * switch-timer is forbidden. Synchronization beacons are sent to the relayd,
 * indexes are sent and metadata is checked for each packet.
 *
 * Name can't be NULL. If no URL is given, the default is to send the data to
 * net://127.0.0.1. The timer_interval is in usec.
 *
 * Return 0 on success else a negative LTTng error code.
 */
extern int lttng_create_session_live(const char *name, const char *url,
		unsigned int timer_interval);

/*
 * Destroy a tracing session.
 *
 * The session will not be usable, tracing will be stopped thus buffers will be
 * flushed.
 *
 * This call will wait for data availability for each domain of the session,
 * which can take an arbitrary amount of time. However, when returning the
 * tracing data is guaranteed to be ready to be read and analyzed.
 *
 * lttng_destroy_session_no_wait() may be used if such a guarantee is not
 * needed.
 *
 * The name can't be NULL here.
 *
 * Return 0 on success else a negative LTTng error code.
 */
extern int lttng_destroy_session(const char *name);

/*
 * Destroy a tracing session.
 *
 * Performs the same function as lttng_destroy_session(), but provides
 * an lttng_destruction_handle which can be used to wait for the completion
 * of the session's destruction. The lttng_destroy_handle can also be used
 * obtain the status and archive location of any implicit session
 * rotation that may have occurred during the session's destruction.
 *
 * Returns LTTNG_OK on success. The returned handle is owned by the caller
 * and must be free'd using lttng_destruction_handle_destroy().
 */
extern enum lttng_error_code lttng_destroy_session_ext(const char *session_name,
		struct lttng_destruction_handle **handle);

/*
 * Behaves exactly like lttng_destroy_session but does not wait for data
 * availability.
 */
extern int lttng_destroy_session_no_wait(const char *name);

/*
 * List all the tracing sessions.
 *
 * Return the number of entries of the "lttng_session" array. The caller
 * must free the returned sessions array directly using free().
 *
 * On error, a negative LTTng error code is returned.
 */
extern int lttng_list_sessions(struct lttng_session **sessions);

/*
 * Get the creation time of an lttng_session object on the session daemon.
 *
 * This function must only be used with lttng_session objects returned
 * by lttng_list_sessions() or lttng_session_create().
 *
 * The creation time returned is a UNIX timestamp; the number of seconds since
 * Epoch (1970-01-01 00:00:00 +0000 (UTC)).
 *
 * Returns LTTNG_OK on success. See lttng-error.h for the meaning of the other
 * return codes.
 */
extern enum lttng_error_code lttng_session_get_creation_time(
		const struct lttng_session *session, uint64_t *creation_time);

/*
 * Set the shared memory path for a session.
 *
 * Sets the (optional) file system path where shared memory buffers will
 * be created for the session. This is useful for buffer extraction on
 * crash, when used with filesystems like pramfs.
 *
 * Return 0 on success else a negative LTTng error code.
 */
extern int lttng_set_session_shm_path(const char *session_name,
		const char *shm_path);

/*
 * Add PID to session tracker.
 *
 * A pid argument >= 0 adds the PID to the session tracker.
 * A pid argument of -1 means "track all PIDs".
 *
 * Return 0 on success else a negative LTTng error code.
 */
extern int lttng_track_pid(struct lttng_handle *handle, int pid);

/*
 * Remove PID from session tracker.
 *
 * A pid argument >= 0 removes the PID from the session tracker.
 * A pid argument of -1 means "untrack all PIDs".
 *
 * Return 0 on success else a negative LTTng error code.
 */
extern int lttng_untrack_pid(struct lttng_handle *handle, int pid);

/*
 * List PIDs in the tracker.
 *
 * enabled is set to whether the PID tracker is enabled.
 * pids is set to an allocated array of PIDs currently tracked. On
 * success, pids must be freed by the caller.
 * nr_pids is set to the number of entries contained by the pids array.
 *
 * Returns 0 on success, else a negative LTTng error code.
 */
extern int lttng_list_tracker_pids(struct lttng_handle *handle,
		int *enabled, int32_t **pids, size_t *nr_pids);

#ifdef __cplusplus
}
#endif

#endif /* LTTNG_SESSION_H */
Commit	Line	Data
1239a312 DG	1	/*
1239a312 DG	2	* Copyright (C) 2014 - David Goulet <dgoulet@efficios.com>
823a1989	3	* Copyright (C) 2019 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
1239a312 DG	4	*
	5	* This library is free software; you can redistribute it and/or modify it
	6	* under the terms of the GNU Lesser General Public License, version 2.1 only,
	7	* as published by the Free Software Foundation.
	8	*
	9	* This library is distributed in the hope that it will be useful, but WITHOUT
	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
	12	* for more details.
	13	*
	14	* You should have received a copy of the GNU Lesser General Public License
	15	* along with this library; if not, write to the Free Software Foundation,
	16	* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	17	*/
	18
	19	#ifndef LTTNG_SESSION_H
	20	#define LTTNG_SESSION_H
	21
	22	#ifdef __cplusplus
	23	extern "C" {
	24	#endif
	25
5feee503	26	struct lttng_session_descriptor;
823a1989	27	struct lttng_destruction_handle;
5feee503	28
1239a312 DG	29	/*
	30	* Basic session information.
	31	*
	32	* The "enabled" field is only used when listing the sessions which indicate if
	33	* it's started or not.
	34	*
	35	* The structures should be initialized to zero before use.
	36	*/
9a720f87	37	#define LTTNG_SESSION_PADDING1 8
1239a312	38	struct lttng_session {
36d2e35d	39	char name[LTTNG_NAME_MAX];
34d7196e JG	40	/*
	41	* Human-readable representation of the trace's destination.
	42	* In the case of a local tracing session, a path is provided:
	43	* /path/to/the/output
	44	*
	45	* In the case of a remote (network) tracing session, the string has
	46	* the following format:
	47	* net://hostname/path:ctrl_port [data: data_port]
	48	*/
1239a312 DG	49	char path[PATH_MAX];
	50	uint32_t enabled; /* enabled/started: 1, disabled/stopped: 0 */
	51	uint32_t snapshot_mode;
	52	unsigned int live_timer_interval; /* usec */
	53
9a720f87 JG	54	/*
	55	* End of public attributes.
	56	* The remaining fields are used to deal with ABI management concerns.
	57	*/
	58
	59	/*
	60	* 32-bit architectures are already naturally aligned on 4 bytes after
	61	* 'live_timer_interval'. However, the offset does not result in a
	62	* natural alignment on 64-bit architectures. Adding 4 bytes of
	63	* padding here results in an aligned offset after 'alignement_padding'
	64	* for both bitnesses.
	65	*
	66	* This was added since not all compilers appear to align unions in the
	67	* same way. Some (e.g. MSVC) do not seem to impose an alignement
	68	* constraint while others (e.g. gcc, clang, icc) seem to align it to
	69	* ensure 'ptr' is naturally aligned.
	70	*/
	71	char alignment_padding[4];
5feee503	72	union {
9a720f87 JG	73	/*
	74	* Ensure the 'extended' union has the same size for both
	75	* 32-bit and 64-bit builds.
	76	*/
5feee503 JG	77	char padding[LTTNG_SESSION_PADDING1];
	78	void *ptr;
	79	} extended;
1239a312 DG	80	};
1239a312 DG	81
5feee503 JG	82	/*
	83	* Create a session on the session daemon from a session descriptor.
	84	*
	85	* See the session descriptor API description in session-descriptor.h
	86	*
	87	* Note that unspecified session descriptor parameters, such as a session's
	88	* name, are updated in the session descriptor if the creation of the session
	89	* succeeds. This allows users to query the session's auto-generated name
	90	* after its creation. Note that other attributes can be queried using the
	91	* session listing API.
	92	*
	93	* Returns LTTNG_OK on success. See lttng-error.h for the meaning of the other
	94	* return codes.
	95	*/
	96	extern enum lttng_error_code lttng_create_session_ext(
	97	struct lttng_session_descriptor *session_descriptor);
	98
1239a312 DG	99	/*
	100	* Create a tracing session using a name and an optional URL.
	101	*
	102	* If _url_ is NULL, no consumer is created for the session. The name can't be
	103	* NULL here.
	104	*
	105	* Return 0 on success else a negative LTTng error code.
	106	*/
	107	extern int lttng_create_session(const char name, const char url);
	108
	109	/*
	110	* Create a tracing session that will exclusively be used for snapshot meaning
	111	* the session will be in no output mode and every channel enabled for that
	112	* session will be set in overwrite mode and in mmap output since splice is not
	113	* supported.
	114	*
	115	* Name can't be NULL. If an url is given, it will be used to create a default
	116	* snapshot output using it as a destination. If NULL, no output will be
	117	* defined and an add-output call will be needed.
	118	*
	119	* Return 0 on success else a negative LTTng error code.
	120	*/
	121	extern int lttng_create_session_snapshot(const char *name,
	122	const char *snapshot_url);
	123
	124	/*
	125	* Create a session exclusively used for live reading.
	126	*
	127	* In this mode, the switch-timer parameter is forced for each UST channel, a
	128	* live-switch-timer is enabled for kernel channels, manually setting
	129	* switch-timer is forbidden. Synchronization beacons are sent to the relayd,
	130	* indexes are sent and metadata is checked for each packet.
	131	*
	132	* Name can't be NULL. If no URL is given, the default is to send the data to
423f4be3	133	* net://127.0.0.1. The timer_interval is in usec.
1239a312 DG	134	*
	135	* Return 0 on success else a negative LTTng error code.
	136	*/
	137	extern int lttng_create_session_live(const char name, const char url,
	138	unsigned int timer_interval);
	139
	140	/*
	141	* Destroy a tracing session.
	142	*
	143	* The session will not be usable, tracing will be stopped thus buffers will be
	144	* flushed.
	145	*
e20ee7c2 JD	146	* This call will wait for data availability for each domain of the session,
	147	* which can take an arbitrary amount of time. However, when returning the
	148	* tracing data is guaranteed to be ready to be read and analyzed.
	149	*
	150	* lttng_destroy_session_no_wait() may be used if such a guarantee is not
	151	* needed.
	152	*
1239a312 DG	153	* The name can't be NULL here.
1239a312 DG	154	*
b3459096	155	* Return 0 on success else a negative LTTng error code.
1239a312 DG	156	*/
	157	extern int lttng_destroy_session(const char *name);
	158
823a1989 JG	159	/*
	160	* Destroy a tracing session.
	161	*
	162	* Performs the same function as lttng_destroy_session(), but provides
	163	* an lttng_destruction_handle which can be used to wait for the completion
	164	* of the session's destruction. The lttng_destroy_handle can also be used
	165	* obtain the status and archive location of any implicit session
6486cfa7	166	* rotation that may have occurred during the session's destruction.
823a1989 JG	167	*
	168	* Returns LTTNG_OK on success. The returned handle is owned by the caller
	169	* and must be free'd using lttng_destruction_handle_destroy().
	170	*/
	171	extern enum lttng_error_code lttng_destroy_session_ext(const char *session_name,
	172	struct lttng_destruction_handle **handle);
	173
e20ee7c2 JD	174	/*
	175	* Behaves exactly like lttng_destroy_session but does not wait for data
	176	* availability.
	177	*/
	178	extern int lttng_destroy_session_no_wait(const char *name);
	179
1239a312 DG	180	/*
	181	* List all the tracing sessions.
	182	*
5feee503 JG	183	* Return the number of entries of the "lttng_session" array. The caller
	184	* must free the returned sessions array directly using free().
	185	*
	186	* On error, a negative LTTng error code is returned.
1239a312 DG	187	*/
	188	extern int lttng_list_sessions(struct lttng_session **sessions);
	189
5feee503 JG	190	/*
	191	* Get the creation time of an lttng_session object on the session daemon.
	192	*
	193	* This function must only be used with lttng_session objects returned
	194	* by lttng_list_sessions() or lttng_session_create().
	195	*
	196	* The creation time returned is a UNIX timestamp; the number of seconds since
	197	* Epoch (1970-01-01 00:00:00 +0000 (UTC)).
	198	*
	199	* Returns LTTNG_OK on success. See lttng-error.h for the meaning of the other
	200	* return codes.
	201	*/
	202	extern enum lttng_error_code lttng_session_get_creation_time(
	203	const struct lttng_session session, uint64_t creation_time);
	204
d7ba1388 MD	205	/*
	206	* Set the shared memory path for a session.
	207	*
	208	* Sets the (optional) file system path where shared memory buffers will
	209	* be created for the session. This is useful for buffer extraction on
	210	* crash, when used with filesystems like pramfs.
	211	*
	212	* Return 0 on success else a negative LTTng error code.
	213	*/
	214	extern int lttng_set_session_shm_path(const char *session_name,
	215	const char *shm_path);
	216
ccf10263 MD	217	/*
	218	* Add PID to session tracker.
	219	*
	220	* A pid argument >= 0 adds the PID to the session tracker.
	221	* A pid argument of -1 means "track all PIDs".
	222	*
	223	* Return 0 on success else a negative LTTng error code.
	224	*/
	225	extern int lttng_track_pid(struct lttng_handle *handle, int pid);
	226
	227	/*
	228	* Remove PID from session tracker.
	229	*
	230	* A pid argument >= 0 removes the PID from the session tracker.
	231	* A pid argument of -1 means "untrack all PIDs".
	232	*
	233	* Return 0 on success else a negative LTTng error code.
	234	*/
	235	extern int lttng_untrack_pid(struct lttng_handle *handle, int pid);
	236
a5dfbb9d MD	237	/*
	238	* List PIDs in the tracker.
	239	*
36dc4128 JG	240	* enabled is set to whether the PID tracker is enabled.
	241	* pids is set to an allocated array of PIDs currently tracked. On
	242	* success, pids must be freed by the caller.
	243	* nr_pids is set to the number of entries contained by the pids array.
a5dfbb9d MD	244	*
	245	* Returns 0 on success, else a negative LTTng error code.
	246	*/
	247	extern int lttng_list_tracker_pids(struct lttng_handle *handle,
	248	int enabled, int32_t pids, size_t nr_pids);
	249
1239a312 DG	250	#ifdef __cplusplus
	251	}
	252	#endif
	253
	254	#endif /* LTTNG_SESSION_H */