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.
52 * Session unique ID generator. The session list lock MUST be
53 * upon update and read of this counter.
57 /* Linked list head */
58 struct cds_list_head head
;
62 * This data structure contains information needed to identify a tracing
63 * session for both LTTng and UST.
67 char hostname
[HOST_NAME_MAX
]; /* Local hostname. */
68 struct ltt_kernel_session
*kernel_session
;
69 struct ltt_ust_session
*ust_session
;
72 * Protect any read/write on this session data structure. This lock must be
73 * acquired *before* using any public functions declared below. Use
74 * session_lock() and session_unlock() for that.
77 struct cds_list_head list
;
78 uint64_t id
; /* session unique identifier */
79 /* Indicates if a destroy command has been applied to this session. */
81 /* UID/GID of the user owning the session */
85 * Network session handle. A value of 0 means that there is no remote
86 * session established.
90 * This consumer is only set when the create_session_uri call is made.
91 * This contains the temporary information for a consumer output. Upon
92 * creation of the UST or kernel session, this consumer, if available, is
93 * copied into those sessions.
95 struct consumer_output
*consumer
;
97 /* Did at least ONE start command has been triggered?. */
98 unsigned int has_been_started
:1;
100 * Is the session active? Start trace command sets this to 1 and the stop
101 * command reset it to 0.
103 unsigned int active
:1;
105 /* Snapshot representation in a session. */
106 struct snapshot snapshot
;
107 /* Indicate if the session has to output the traces or not. */
108 unsigned int output_traces
;
110 * This session is in snapshot mode. This means that every channel enabled
111 * will be set in overwrite mode and mmap. It is considered exclusively for
114 unsigned int snapshot_mode
;
116 * Timer set when the session is created for live reading.
118 unsigned int live_timer
;
120 * Path where to keep the shared memory files.
122 char shm_path
[PATH_MAX
];
124 * Node in ltt_sessions_ht_by_id.
126 struct lttng_ht_node_u64 node
;
128 * The current archive id corresponds to the number of session rotations
129 * that have occurred for this session. The archive id
130 * is used to tag the "generation" of a stream. This tag allows the
131 * consumer and relay daemons to track when a given stream was created
132 * during the lifetime of a session.
134 * For instance, if a stream is created after a session rotation was
135 * launched, the consumer and relay daemons must not check its position
136 * to determine if that specific session rotation was completed. It is
137 * implicitly "completed" since the stream appeared _after_ the session
138 * rotation was initiated.
140 uint64_t current_archive_id
;
142 * Rotation is considered pending between the time it is launched up
143 * until the moment when the data has been writen at the destination
144 * and the trace archive has been renamed.
146 * When tracing locally, only 'rotation_pending_local' is used since
147 * no remote checks are needed. However, when tracing to a relay daemon,
148 * a second check is needed to ensure that the data has been
149 * commited at the remote destination.
151 bool rotation_pending_local
;
152 bool rotation_pending_relay
;
153 /* Current state of a rotation. */
154 enum lttng_rotation_state rotation_state
;
157 * When the rotation is in progress, the temporary path name is
158 * stored here. When the rotation is complete, the final path name
159 * is here and can be queried with the rotate_pending call.
161 char current_rotate_path
[LTTNG_PATH_MAX
];
163 * The path where the consumer is currently writing after the first
166 char active_tracing_path
[LTTNG_PATH_MAX
];
169 * The timestamp of the beginning of the previous chunk. For the
170 * first chunk, this is the "lttng start" timestamp. For the
171 * subsequent ones, this copies the current_chunk_start_ts value when
172 * a new rotation starts. This value is used to set the name of a
173 * complete chunk directory, ex: "last_chunk_start_ts-now()".
175 time_t last_chunk_start_ts
;
177 * This is the timestamp when a new chunk starts. When a new rotation
178 * starts, we copy this value to last_chunk_start_ts and replace it
179 * with the current timestamp.
181 time_t current_chunk_start_ts
;
183 * Timer to check periodically if a relay and/or consumer has completed
186 bool rotation_pending_check_timer_enabled
;
187 timer_t rotation_pending_check_timer
;
188 /* Timer to periodically rotate a session. */
189 bool rotation_schedule_timer_enabled
;
190 timer_t rotation_schedule_timer
;
191 /* Value for periodic rotations, 0 if disabled. */
192 uint64_t rotate_timer_period
;
193 /* Value for size-based rotations, 0 if disabled. */
194 uint64_t rotate_size
;
196 * Keep a state if this session was rotated after the last stop command.
197 * We only allow one rotation after a stop. At destroy, we also need to
198 * know if a rotation occurred since the last stop to rename the current
201 bool rotated_after_last_stop
;
203 * Condition and trigger for size-based rotations.
205 struct lttng_condition
*rotate_condition
;
206 struct lttng_trigger
*rotate_trigger
;
210 int session_create(char *name
, uid_t uid
, gid_t gid
);
212 void session_lock(struct ltt_session
*session
);
213 void session_lock_list(void);
214 int session_trylock_list(void);
215 void session_unlock(struct ltt_session
*session
);
216 void session_unlock_list(void);
218 void session_destroy(struct ltt_session
*session
);
220 bool session_get(struct ltt_session
*session
);
221 void session_put(struct ltt_session
*session
);
223 enum consumer_dst_type
session_get_consumer_destination_type(
224 const struct ltt_session
*session
);
225 const char *session_get_net_consumer_hostname(
226 const struct ltt_session
*session
);
227 void session_get_net_consumer_ports(
228 const struct ltt_session
*session
,
229 uint16_t *control_port
, uint16_t *data_port
);
230 struct lttng_trace_archive_location
*session_get_trace_archive_location(
231 struct ltt_session
*session
);
233 struct ltt_session
*session_find_by_name(const char *name
);
234 struct ltt_session
*session_find_by_id(uint64_t id
);
235 struct ltt_session_list
*session_get_list(void);
237 int session_access_ok(struct ltt_session
*session
, uid_t uid
, gid_t gid
);
239 int session_reset_rotation_state(struct ltt_session
*session
,
240 enum lttng_rotation_state result
);
242 #endif /* _LTT_SESSION_H */