2 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
4 * SPDX-License-Identifier: GPL-2.0-only
13 #include <urcu/list.h>
15 #include <common/hashtable/hashtable.h>
16 #include <common/dynamic-array.h>
17 #include <lttng/rotation.h>
18 #include <lttng/location.h>
19 #include <lttng/lttng-error.h>
22 #include "trace-kernel.h"
25 struct ltt_ust_session
;
27 typedef void (*ltt_session_destroy_notifier
)(const struct ltt_session
*session
,
29 typedef void (*ltt_session_clear_notifier
)(const struct ltt_session
*session
,
33 * Tracing session list
35 * Statically declared in session.c and can be accessed by using
36 * session_get_list() function that returns the pointer to the list.
38 struct ltt_session_list
{
40 * This lock protects any read/write access to the list and
41 * next_uuid. All public functions in session.c acquire this
42 * lock and release it before returning. If none of those
43 * functions are used, the lock MUST be acquired in order to
44 * iterate or/and do any actions on that list.
48 * This condition variable is signaled on every removal from
51 pthread_cond_t removal_cond
;
54 * Session unique ID generator. The session list lock MUST be
55 * upon update and read of this counter.
59 /* Linked list head */
60 struct cds_list_head head
;
64 * This data structure contains information needed to identify a tracing
65 * session for both LTTng and UST.
69 bool has_auto_generated_name
;
70 bool name_contains_creation_time
;
71 char hostname
[LTTNG_HOST_NAME_MAX
]; /* Local hostname. */
72 /* Path of the last closed chunk. */
73 char last_chunk_path
[LTTNG_PATH_MAX
];
75 struct ltt_kernel_session
*kernel_session
;
76 struct ltt_ust_session
*ust_session
;
79 * Protect any read/write on this session data structure. This lock must be
80 * acquired *before* using any public functions declared below. Use
81 * session_lock() and session_unlock() for that.
84 struct cds_list_head list
;
85 uint64_t id
; /* session unique identifier */
86 /* Indicates if the session has been added to the session list and ht.*/
88 /* Indicates if a destroy command has been applied to this session. */
90 /* UID/GID of the user owning the session */
94 * Network session handle. A value of 0 means that there is no remote
95 * session established.
99 * This consumer is only set when the create_session_uri call is made.
100 * This contains the temporary information for a consumer output. Upon
101 * creation of the UST or kernel session, this consumer, if available, is
102 * copied into those sessions.
104 struct consumer_output
*consumer
;
106 * Indicates whether or not the user has specified an output directory
107 * or if it was configured using the default configuration.
109 bool has_user_specified_directory
;
110 /* Did at least ONE start command has been triggered?. */
111 unsigned int has_been_started
:1;
113 * Is the session active? Start trace command sets this to 1 and the stop
114 * command reset it to 0.
116 unsigned int active
:1;
118 /* Snapshot representation in a session. */
119 struct snapshot snapshot
;
120 /* Indicate if the session has to output the traces or not. */
121 unsigned int output_traces
;
123 * This session is in snapshot mode. This means that channels enabled
124 * will be set in overwrite mode by default and must be in mmap
125 * output mode. Note that snapshots can be taken on a session that
126 * is not in "snapshot_mode". This parameter only affects channel
129 unsigned int snapshot_mode
;
131 * A session that has channels that don't use 'mmap' output can't be
132 * used to capture snapshots. This is set to true whenever a
133 * 'splice' kernel channel is enabled.
135 bool has_non_mmap_channel
;
137 * Timer set when the session is created for live reading.
139 unsigned int live_timer
;
141 * Path where to keep the shared memory files.
143 char shm_path
[PATH_MAX
];
145 * Node in ltt_sessions_ht_by_id.
147 struct lttng_ht_node_u64 node
;
149 * Node in ltt_sessions_ht_by_name.
151 struct lttng_ht_node_str node_by_name
;
153 * Timer to check periodically if a relay and/or consumer has completed
156 bool rotation_pending_check_timer_enabled
;
157 timer_t rotation_pending_check_timer
;
158 /* Timer to periodically rotate a session. */
159 bool rotation_schedule_timer_enabled
;
160 timer_t rotation_schedule_timer
;
161 /* Value for periodic rotations, 0 if disabled. */
162 uint64_t rotate_timer_period
;
163 /* Value for size-based rotations, 0 if disabled. */
164 uint64_t rotate_size
;
166 * Keep a state if this session was rotated after the last stop command.
167 * We only allow one rotation after a stop. At destroy, we also need to
168 * know if a rotation occurred since the last stop to rename the current
169 * chunk. After a stop followed by rotate, all subsequent clear
170 * (without prior start) will succeed, but will be effect-less.
172 bool rotated_after_last_stop
;
174 * Track whether the session was cleared after last stop. All subsequent
175 * clear (without prior start) will succeed, but will be effect-less. A
176 * subsequent rotate (without prior start) will return an error.
178 bool cleared_after_last_stop
;
180 * True if the session has had an explicit non-quiet rotation.
184 * Condition and trigger for size-based rotations.
186 struct lttng_condition
*rotate_condition
;
187 struct lttng_trigger
*rotate_trigger
;
188 LTTNG_OPTIONAL(uint64_t) most_recent_chunk_id
;
189 struct lttng_trace_chunk
*current_trace_chunk
;
190 struct lttng_trace_chunk
*chunk_being_archived
;
191 /* Current state of a rotation. */
192 enum lttng_rotation_state rotation_state
;
194 char *last_archived_chunk_name
;
195 LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id
;
196 struct lttng_dynamic_array destroy_notifiers
;
197 struct lttng_dynamic_array clear_notifiers
;
198 /* Session base path override. Set non-null. */
202 enum lttng_error_code
session_create(const char *name
, uid_t uid
, gid_t gid
,
203 struct ltt_session
**out_session
);
204 void session_lock(struct ltt_session
*session
);
205 void session_unlock(struct ltt_session
*session
);
208 * The session list lock covers more ground than its name implies. While
209 * it does protect against concurent mutations of the session list, it is
210 * also used as a multi-session lock when synchronizing newly-registered
211 * 'user space tracer' and 'agent' applications.
213 * In other words, it prevents tracer configurations from changing while they
214 * are being transmitted to the various applications.
216 void session_lock_list(void);
217 int session_trylock_list(void);
218 void session_unlock_list(void);
220 void session_destroy(struct ltt_session
*session
);
221 int session_add_destroy_notifier(struct ltt_session
*session
,
222 ltt_session_destroy_notifier notifier
, void *user_data
);
224 int session_add_clear_notifier(struct ltt_session
*session
,
225 ltt_session_clear_notifier notifier
, void *user_data
);
226 void session_notify_clear(struct ltt_session
*session
);
228 bool session_get(struct ltt_session
*session
);
229 void session_put(struct ltt_session
*session
);
231 enum consumer_dst_type
session_get_consumer_destination_type(
232 const struct ltt_session
*session
);
233 const char *session_get_net_consumer_hostname(
234 const struct ltt_session
*session
);
235 void session_get_net_consumer_ports(
236 const struct ltt_session
*session
,
237 uint16_t *control_port
, uint16_t *data_port
);
238 struct lttng_trace_archive_location
*session_get_trace_archive_location(
239 const struct ltt_session
*session
);
241 struct ltt_session
*session_find_by_name(const char *name
);
242 struct ltt_session
*session_find_by_id(uint64_t id
);
244 struct ltt_session_list
*session_get_list(void);
245 void session_list_wait_empty(void);
247 bool session_access_ok(struct ltt_session
*session
, uid_t uid
);
249 int session_reset_rotation_state(struct ltt_session
*session
,
250 enum lttng_rotation_state result
);
252 /* Create a new trace chunk object from the session's configuration. */
253 struct lttng_trace_chunk
*session_create_new_trace_chunk(
254 const struct ltt_session
*session
,
255 const struct consumer_output
*consumer_output_override
,
256 const char *session_base_path_override
,
257 const char *chunk_name_override
);
260 * Set `new_trace_chunk` as the session's current trace chunk. A reference
261 * to `new_trace_chunk` is acquired by the session. The chunk is created
262 * on remote peers (consumer and relay daemons).
264 * A reference to the session's current trace chunk is returned through
265 * `current_session_trace_chunk` on success.
267 int session_set_trace_chunk(struct ltt_session
*session
,
268 struct lttng_trace_chunk
*new_trace_chunk
,
269 struct lttng_trace_chunk
**current_session_trace_chunk
);
272 * Close a chunk on the remote peers of a session. Has no effect on the
273 * ltt_session itself.
275 int session_close_trace_chunk(struct ltt_session
*session
,
276 struct lttng_trace_chunk
*trace_chunk
,
277 enum lttng_trace_chunk_command_type close_command
,
280 /* Open a packet in all channels of a given session. */
281 enum lttng_error_code
session_open_packets(struct ltt_session
*session
);
283 bool session_output_supports_trace_chunks(const struct ltt_session
*session
);
286 * Sample the id of a session looked up via its name.
287 * Here the term "sampling" hint the caller that this return the id at a given
288 * point in time with no guarantee that the session for which the id was
289 * sampled still exist at that point.
291 * Return 0 when the session is not found,
292 * Return 1 when the session is found and set `id`.
294 bool sample_session_id_by_name(const char *name
, uint64_t *id
);
296 #endif /* _LTT_SESSION_H */