2 * Copyright (C) 2014 - David Goulet <dgoulet@efficios.com>
4 * This library is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU Lesser General Public License, version 2.1 only,
6 * as published by the Free Software Foundation.
8 * This library is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
13 * You should have received a copy of the GNU Lesser General Public License
14 * along with this library; if not, write to the Free Software Foundation,
15 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 #ifndef LTTNG_SESSION_H
19 #define LTTNG_SESSION_H
26 * Basic session information.
28 * The "enabled" field is only used when listing the sessions which indicate if
29 * it's started or not.
31 * The structures should be initialized to zero before use.
33 #define LTTNG_SESSION_PADDING1 12
34 struct lttng_session
{
35 char name
[LTTNG_NAME_MAX
];
36 /* The path where traces are written */
38 uint32_t enabled
; /* enabled/started: 1, disabled/stopped: 0 */
39 uint32_t snapshot_mode
;
40 unsigned int live_timer_interval
; /* usec */
42 char padding
[LTTNG_SESSION_PADDING1
];
46 * Create a tracing session using a name and an optional URL.
48 * If _url_ is NULL, no consumer is created for the session. The name can't be
51 * Return 0 on success else a negative LTTng error code.
53 extern int lttng_create_session(const char *name
, const char *url
);
56 * Create a tracing session that will exclusively be used for snapshot meaning
57 * the session will be in no output mode and every channel enabled for that
58 * session will be set in overwrite mode and in mmap output since splice is not
61 * Name can't be NULL. If an url is given, it will be used to create a default
62 * snapshot output using it as a destination. If NULL, no output will be
63 * defined and an add-output call will be needed.
65 * Return 0 on success else a negative LTTng error code.
67 extern int lttng_create_session_snapshot(const char *name
,
68 const char *snapshot_url
);
71 * Create a session exclusively used for live reading.
73 * In this mode, the switch-timer parameter is forced for each UST channel, a
74 * live-switch-timer is enabled for kernel channels, manually setting
75 * switch-timer is forbidden. Synchronization beacons are sent to the relayd,
76 * indexes are sent and metadata is checked for each packet.
78 * Name can't be NULL. If no URL is given, the default is to send the data to
79 * net://127.0.0.1. The timer_interval is in usec and by default set to 1000000
82 * Return 0 on success else a negative LTTng error code.
84 extern int lttng_create_session_live(const char *name
, const char *url
,
85 unsigned int timer_interval
);
88 * Destroy a tracing session.
90 * The session will not be usable, tracing will be stopped thus buffers will be
93 * This call will wait for data availability for each domain of the session,
94 * which can take an arbitrary amount of time. However, when returning the
95 * tracing data is guaranteed to be ready to be read and analyzed.
97 * lttng_destroy_session_no_wait() may be used if such a guarantee is not
100 * The name can't be NULL here.
102 * Return 0 on success else a negative LTTng error code.
104 extern int lttng_destroy_session(const char *name
);
107 * Behaves exactly like lttng_destroy_session but does not wait for data
110 extern int lttng_destroy_session_no_wait(const char *name
);
113 * List all the tracing sessions.
115 * Return the size (number of entries) of the "lttng_session" array. Caller
116 * must free sessions. On error, a negative LTTng error code is returned.
118 extern int lttng_list_sessions(struct lttng_session
**sessions
);
121 * Set the shared memory path for a session.
123 * Sets the (optional) file system path where shared memory buffers will
124 * be created for the session. This is useful for buffer extraction on
125 * crash, when used with filesystems like pramfs.
127 * Return 0 on success else a negative LTTng error code.
129 extern int lttng_set_session_shm_path(const char *session_name
,
130 const char *shm_path
);
133 * Add PID to session tracker.
135 * A pid argument >= 0 adds the PID to the session tracker.
136 * A pid argument of -1 means "track all PIDs".
138 * Return 0 on success else a negative LTTng error code.
140 extern int lttng_track_pid(struct lttng_handle
*handle
, int pid
);
143 * Remove PID from session tracker.
145 * A pid argument >= 0 removes the PID from the session tracker.
146 * A pid argument of -1 means "untrack all PIDs".
148 * Return 0 on success else a negative LTTng error code.
150 extern int lttng_untrack_pid(struct lttng_handle
*handle
, int pid
);
153 * List PIDs in the tracker.
155 * enabled is set to whether the PID tracker is enabled.
156 * pids is set to an allocated array of PIDs currently tracked. On
157 * success, pids must be freed by the caller.
158 * nr_pids is set to the number of entries contained by the pids array.
160 * Returns 0 on success, else a negative LTTng error code.
162 extern int lttng_list_tracker_pids(struct lttng_handle
*handle
,
163 int *enabled
, int32_t **pids
, size_t *nr_pids
);
166 * Ask the session daemon where the data for this session is currently being
167 * written to. If rotations occured during a session, this call is useful to
168 * know the location of the last chunk.
170 * Return 0 and allocate chunk_path if rotations occured for this session, the
171 * caller needs to free chunk_path.
172 * Return 1 if no rotation occured during the session, chunk_path is left
175 * Return a negative LTTng error code on error (readable with lttng_strerror).
177 * FIXME: Return an lttng_location object rather than a path.
179 extern int lttng_session_get_current_archive_location(const char *session_name
,
186 #endif /* LTTNG_SESSION_H */
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