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
];
37 * Human-readable representation of the trace's destination.
38 * In the case of a local tracing session, a path is provided:
41 * In the case of a remote (network) tracing session, the string has
42 * the following format:
43 * net://hostname/path:ctrl_port [data: data_port]
46 uint32_t enabled
; /* enabled/started: 1, disabled/stopped: 0 */
47 uint32_t snapshot_mode
;
48 unsigned int live_timer_interval
; /* usec */
50 char padding
[LTTNG_SESSION_PADDING1
];
54 * Create a tracing session using a name and an optional URL.
56 * If _url_ is NULL, no consumer is created for the session. The name can't be
59 * Return 0 on success else a negative LTTng error code.
61 extern int lttng_create_session(const char *name
, const char *url
);
64 * Create a tracing session that will exclusively be used for snapshot meaning
65 * the session will be in no output mode and every channel enabled for that
66 * session will be set in overwrite mode and in mmap output since splice is not
69 * Name can't be NULL. If an url is given, it will be used to create a default
70 * snapshot output using it as a destination. If NULL, no output will be
71 * defined and an add-output call will be needed.
73 * Return 0 on success else a negative LTTng error code.
75 extern int lttng_create_session_snapshot(const char *name
,
76 const char *snapshot_url
);
79 * Create a session exclusively used for live reading.
81 * In this mode, the switch-timer parameter is forced for each UST channel, a
82 * live-switch-timer is enabled for kernel channels, manually setting
83 * switch-timer is forbidden. Synchronization beacons are sent to the relayd,
84 * indexes are sent and metadata is checked for each packet.
86 * Name can't be NULL. If no URL is given, the default is to send the data to
87 * net://127.0.0.1. The timer_interval is in usec.
89 * Return 0 on success else a negative LTTng error code.
91 extern int lttng_create_session_live(const char *name
, const char *url
,
92 unsigned int timer_interval
);
95 * Destroy a tracing session.
97 * The session will not be usable, tracing will be stopped thus buffers will be
100 * This call will wait for data availability for each domain of the session,
101 * which can take an arbitrary amount of time. However, when returning the
102 * tracing data is guaranteed to be ready to be read and analyzed.
104 * lttng_destroy_session_no_wait() may be used if such a guarantee is not
107 * The name can't be NULL here.
109 * Return 0 on success else a negative LTTng error code.
111 extern int lttng_destroy_session(const char *name
);
114 * Behaves exactly like lttng_destroy_session but does not wait for data
117 extern int lttng_destroy_session_no_wait(const char *name
);
120 * List all the tracing sessions.
122 * Return the size (number of entries) of the "lttng_session" array. Caller
123 * must free sessions. On error, a negative LTTng error code is returned.
125 extern int lttng_list_sessions(struct lttng_session
**sessions
);
128 * Set the shared memory path for a session.
130 * Sets the (optional) file system path where shared memory buffers will
131 * be created for the session. This is useful for buffer extraction on
132 * crash, when used with filesystems like pramfs.
134 * Return 0 on success else a negative LTTng error code.
136 extern int lttng_set_session_shm_path(const char *session_name
,
137 const char *shm_path
);
140 * Add PID to session tracker.
142 * A pid argument >= 0 adds the PID to the session tracker.
143 * A pid argument of -1 means "track all PIDs".
145 * Return 0 on success else a negative LTTng error code.
147 extern int lttng_track_pid(struct lttng_handle
*handle
, int pid
);
150 * Remove PID from session tracker.
152 * A pid argument >= 0 removes the PID from the session tracker.
153 * A pid argument of -1 means "untrack all PIDs".
155 * Return 0 on success else a negative LTTng error code.
157 extern int lttng_untrack_pid(struct lttng_handle
*handle
, int pid
);
160 * List PIDs in the tracker.
162 * enabled is set to whether the PID tracker is enabled.
163 * pids is set to an allocated array of PIDs currently tracked. On
164 * success, pids must be freed by the caller.
165 * nr_pids is set to the number of entries contained by the pids array.
167 * Returns 0 on success, else a negative LTTng error code.
169 extern int lttng_list_tracker_pids(struct lttng_handle
*handle
,
170 int *enabled
, int32_t **pids
, size_t *nr_pids
);
176 #endif /* LTTNG_SESSION_H */
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