2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License, version 2 only,
6 * as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 #ifndef _LTT_SESSION_H
19 #define _LTT_SESSION_H
23 #include <urcu/list.h>
25 #include <common/hashtable/hashtable.h>
26 #include <lttng/rotation.h>
27 #include <lttng/location.h>
30 #include "trace-kernel.h"
33 struct ltt_ust_session
;
36 * Tracing session list
38 * Statically declared in session.c and can be accessed by using
39 * session_get_list() function that returns the pointer to the list.
41 struct ltt_session_list
{
43 * This lock protects any read/write access to the list and
44 * next_uuid. All public functions in session.c acquire this
45 * lock and release it before returning. If none of those
46 * functions are used, the lock MUST be acquired in order to
47 * iterate or/and do any actions on that list.
51 * This condition variable is signaled on every removal from
54 pthread_cond_t removal_cond
;
57 * Session unique ID generator. The session list lock MUST be
58 * upon update and read of this counter.
62 /* Linked list head */
63 struct cds_list_head head
;
67 * This data structure contains information needed to identify a tracing
68 * session for both LTTng and UST.
72 char hostname
[HOST_NAME_MAX
]; /* Local hostname. */
73 struct ltt_kernel_session
*kernel_session
;
74 struct ltt_ust_session
*ust_session
;
77 * Protect any read/write on this session data structure. This lock must be
78 * acquired *before* using any public functions declared below. Use
79 * session_lock() and session_unlock() for that.
82 struct cds_list_head list
;
83 uint64_t id
; /* session unique identifier */
84 /* Indicates if the session has been added to the session list and ht.*/
86 /* Indicates if a destroy command has been applied to this session. */
88 /* UID/GID of the user owning the session */
92 * Network session handle. A value of 0 means that there is no remote
93 * session established.
97 * This consumer is only set when the create_session_uri call is made.
98 * This contains the temporary information for a consumer output. Upon
99 * creation of the UST or kernel session, this consumer, if available, is
100 * copied into those sessions.
102 struct consumer_output
*consumer
;
104 /* Did at least ONE start command has been triggered?. */
105 unsigned int has_been_started
:1;
107 * Is the session active? Start trace command sets this to 1 and the stop
108 * command reset it to 0.
110 unsigned int active
:1;
112 /* Snapshot representation in a session. */
113 struct snapshot snapshot
;
114 /* Indicate if the session has to output the traces or not. */
115 unsigned int output_traces
;
117 * This session is in snapshot mode. This means that channels enabled
118 * will be set in overwrite mode by default and must be in mmap
119 * output mode. Note that snapshots can be taken on a session that
120 * is not in "snapshot_mode". This parameter only affects channel
123 unsigned int snapshot_mode
;
125 * A session that has channels that don't use 'mmap' output can't be
126 * used to capture snapshots. This is set to true whenever a
127 * 'splice' kernel channel is enabled.
129 bool has_non_mmap_channel
;
131 * Timer set when the session is created for live reading.
133 unsigned int live_timer
;
135 * Path where to keep the shared memory files.
137 char shm_path
[PATH_MAX
];
139 * Node in ltt_sessions_ht_by_id.
141 struct lttng_ht_node_u64 node
;
143 * The current archive id corresponds to the number of session rotations
144 * that have occurred for this session. The archive id
145 * is used to tag the "generation" of a stream. This tag allows the
146 * consumer and relay daemons to track when a given stream was created
147 * during the lifetime of a session.
149 * For instance, if a stream is created after a session rotation was
150 * launched, the consumer and relay daemons must not check its position
151 * to determine if that specific session rotation was completed. It is
152 * implicitly "completed" since the stream appeared _after_ the session
153 * rotation was initiated.
155 uint64_t current_archive_id
;
157 * Rotation is considered pending between the time it is launched up
158 * until the moment when the data has been writen at the destination
159 * and the trace archive has been renamed.
161 * When tracing locally, only 'rotation_pending_local' is used since
162 * no remote checks are needed. However, when tracing to a relay daemon,
163 * a second check is needed to ensure that the data has been
164 * commited at the remote destination.
166 bool rotation_pending_local
;
167 bool rotation_pending_relay
;
168 /* Current state of a rotation. */
169 enum lttng_rotation_state rotation_state
;
172 * When the rotation is in progress, the temporary path name is
173 * stored here. When the rotation is complete, the final path name
174 * is here and can be queried with the rotate_pending call.
176 char current_rotate_path
[LTTNG_PATH_MAX
];
178 * The path where the consumer is currently writing after the first
181 char active_tracing_path
[LTTNG_PATH_MAX
];
184 * The timestamp of the beginning of the previous chunk. For the
185 * first chunk, this is the "lttng start" timestamp. For the
186 * subsequent ones, this copies the current_chunk_start_ts value when
187 * a new rotation starts. This value is used to set the name of a
188 * complete chunk directory, ex: "last_chunk_start_ts-now()".
190 time_t last_chunk_start_ts
;
192 * This is the timestamp when a new chunk starts. When a new rotation
193 * starts, we copy this value to last_chunk_start_ts and replace it
194 * with the current timestamp.
196 time_t current_chunk_start_ts
;
198 * Timer to check periodically if a relay and/or consumer has completed
201 bool rotation_pending_check_timer_enabled
;
202 timer_t rotation_pending_check_timer
;
203 /* Timer to periodically rotate a session. */
204 bool rotation_schedule_timer_enabled
;
205 timer_t rotation_schedule_timer
;
206 /* Value for periodic rotations, 0 if disabled. */
207 uint64_t rotate_timer_period
;
208 /* Value for size-based rotations, 0 if disabled. */
209 uint64_t rotate_size
;
211 * Keep a state if this session was rotated after the last stop command.
212 * We only allow one rotation after a stop. At destroy, we also need to
213 * know if a rotation occurred since the last stop to rename the current
216 bool rotated_after_last_stop
;
218 * Condition and trigger for size-based rotations.
220 struct lttng_condition
*rotate_condition
;
221 struct lttng_trigger
*rotate_trigger
;
225 int session_create(char *name
, uid_t uid
, gid_t gid
);
227 void session_lock(struct ltt_session
*session
);
228 void session_lock_list(void);
229 int session_trylock_list(void);
230 void session_unlock(struct ltt_session
*session
);
231 void session_unlock_list(void);
233 void session_destroy(struct ltt_session
*session
);
235 bool session_get(struct ltt_session
*session
);
236 void session_put(struct ltt_session
*session
);
238 enum consumer_dst_type
session_get_consumer_destination_type(
239 const struct ltt_session
*session
);
240 const char *session_get_net_consumer_hostname(
241 const struct ltt_session
*session
);
242 void session_get_net_consumer_ports(
243 const struct ltt_session
*session
,
244 uint16_t *control_port
, uint16_t *data_port
);
245 struct lttng_trace_archive_location
*session_get_trace_archive_location(
246 struct ltt_session
*session
);
248 struct ltt_session
*session_find_by_name(const char *name
);
249 struct ltt_session
*session_find_by_id(uint64_t id
);
251 struct ltt_session_list
*session_get_list(void);
252 void session_list_wait_empty(void);
254 int session_access_ok(struct ltt_session
*session
, uid_t uid
, gid_t gid
);
256 int session_reset_rotation_state(struct ltt_session
*session
,
257 enum lttng_rotation_state result
);
259 #endif /* _LTT_SESSION_H */