e6ed40cc2927f624ce3255492a91e129edcb5a8c
[lttng-tools.git] / src / bin / lttng-sessiond / session.h
1 /*
2 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
3 *
4 * SPDX-License-Identifier: GPL-2.0-only
5 *
6 */
7
8 #ifndef _LTT_SESSION_H
9 #define _LTT_SESSION_H
10
11 #include <limits.h>
12 #include <stdbool.h>
13 #include <urcu/list.h>
14
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>
20
21 #include "snapshot.h"
22 #include "trace-kernel.h"
23 #include "consumer.h"
24
25 struct ltt_ust_session;
26
27 typedef void (*ltt_session_destroy_notifier)(const struct ltt_session *session,
28 void *user_data);
29 typedef void (*ltt_session_clear_notifier)(const struct ltt_session *session,
30 void *user_data);
31
32 /*
33 * Tracing session list
34 *
35 * Statically declared in session.c and can be accessed by using
36 * session_get_list() function that returns the pointer to the list.
37 */
38 struct ltt_session_list {
39 /*
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.
45 */
46 pthread_mutex_t lock;
47 /*
48 * This condition variable is signaled on every removal from
49 * the session list.
50 */
51 pthread_cond_t removal_cond;
52
53 /*
54 * Session unique ID generator. The session list lock MUST be
55 * upon update and read of this counter.
56 */
57 uint64_t next_uuid;
58
59 /* Linked list head */
60 struct cds_list_head head;
61 };
62
63 /*
64 * This data structure contains information needed to identify a tracing
65 * session for both LTTng and UST.
66 */
67 struct ltt_session {
68 char name[NAME_MAX];
69 bool has_auto_generated_name;
70 bool name_contains_creation_time;
71 char hostname[HOST_NAME_MAX]; /* Local hostname. */
72 /* Path of the last closed chunk. */
73 char last_chunk_path[LTTNG_PATH_MAX];
74 time_t creation_time;
75 struct ltt_kernel_session *kernel_session;
76 struct ltt_ust_session *ust_session;
77 struct urcu_ref ref;
78 /*
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.
82 */
83 pthread_mutex_t lock;
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.*/
87 bool published;
88 /* Indicates if a destroy command has been applied to this session. */
89 bool destroyed;
90 /* UID/GID of the user owning the session */
91 uid_t uid;
92 gid_t gid;
93 /*
94 * Network session handle. A value of 0 means that there is no remote
95 * session established.
96 */
97 uint64_t net_handle;
98 /*
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.
103 */
104 struct consumer_output *consumer;
105 /*
106 * Indicates whether or not the user has specified an output directory
107 * or if it was configured using the default configuration.
108 */
109 bool has_user_specified_directory;
110 /* Did at least ONE start command has been triggered?. */
111 unsigned int has_been_started:1;
112 /*
113 * Is the session active? Start trace command sets this to 1 and the stop
114 * command reset it to 0.
115 */
116 unsigned int active:1;
117
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;
122 /*
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
127 * creation defaults.
128 */
129 unsigned int snapshot_mode;
130 /*
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.
134 */
135 bool has_non_mmap_channel;
136 /*
137 * Timer set when the session is created for live reading.
138 */
139 unsigned int live_timer;
140 /*
141 * Path where to keep the shared memory files.
142 */
143 char shm_path[PATH_MAX];
144 /*
145 * Node in ltt_sessions_ht_by_id.
146 */
147 struct lttng_ht_node_u64 node;
148 /*
149 * Timer to check periodically if a relay and/or consumer has completed
150 * the last rotation.
151 */
152 bool rotation_pending_check_timer_enabled;
153 timer_t rotation_pending_check_timer;
154 /* Timer to periodically rotate a session. */
155 bool rotation_schedule_timer_enabled;
156 timer_t rotation_schedule_timer;
157 /* Value for periodic rotations, 0 if disabled. */
158 uint64_t rotate_timer_period;
159 /* Value for size-based rotations, 0 if disabled. */
160 uint64_t rotate_size;
161 /*
162 * Keep a state if this session was rotated after the last stop command.
163 * We only allow one rotation after a stop. At destroy, we also need to
164 * know if a rotation occurred since the last stop to rename the current
165 * chunk. After a stop followed by rotate, all subsequent clear
166 * (without prior start) will succeed, but will be effect-less.
167 */
168 bool rotated_after_last_stop;
169 /*
170 * Track whether the session was cleared after last stop. All subsequent
171 * clear (without prior start) will succeed, but will be effect-less. A
172 * subsequent rotate (without prior start) will return an error.
173 */
174 bool cleared_after_last_stop;
175 /*
176 * True if the session has had an explicit non-quiet rotation.
177 */
178 bool rotated;
179 /*
180 * Condition and trigger for size-based rotations.
181 */
182 struct lttng_condition *rotate_condition;
183 struct lttng_trigger *rotate_trigger;
184 LTTNG_OPTIONAL(uint64_t) most_recent_chunk_id;
185 struct lttng_trace_chunk *current_trace_chunk;
186 struct lttng_trace_chunk *chunk_being_archived;
187 /* Current state of a rotation. */
188 enum lttng_rotation_state rotation_state;
189 bool quiet_rotation;
190 char *last_archived_chunk_name;
191 LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id;
192 struct lttng_dynamic_array destroy_notifiers;
193 struct lttng_dynamic_array clear_notifiers;
194 /* Session base path override. Set non-null. */
195 char *base_path;
196 };
197
198 enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
199 struct ltt_session **out_session);
200 void session_lock(struct ltt_session *session);
201 void session_unlock(struct ltt_session *session);
202
203 /*
204 * The session list lock covers more ground than its name implies. While
205 * it does protect against concurent mutations of the session list, it is
206 * also used as a multi-session lock when synchronizing newly-registered
207 * 'user space tracer' and 'agent' applications.
208 *
209 * In other words, it prevents session configurations from changing while they
210 * are being transmitted to the various applications.
211 */
212 void session_lock_list(void);
213 int session_trylock_list(void);
214 void session_unlock_list(void);
215
216 void session_destroy(struct ltt_session *session);
217 int session_add_destroy_notifier(struct ltt_session *session,
218 ltt_session_destroy_notifier notifier, void *user_data);
219
220 int session_add_clear_notifier(struct ltt_session *session,
221 ltt_session_clear_notifier notifier, void *user_data);
222 void session_notify_clear(struct ltt_session *session);
223
224 bool session_get(struct ltt_session *session);
225 void session_put(struct ltt_session *session);
226
227 enum consumer_dst_type session_get_consumer_destination_type(
228 const struct ltt_session *session);
229 const char *session_get_net_consumer_hostname(
230 const struct ltt_session *session);
231 void session_get_net_consumer_ports(
232 const struct ltt_session *session,
233 uint16_t *control_port, uint16_t *data_port);
234 struct lttng_trace_archive_location *session_get_trace_archive_location(
235 const struct ltt_session *session);
236
237 struct ltt_session *session_find_by_name(const char *name);
238 struct ltt_session *session_find_by_id(uint64_t id);
239
240 struct ltt_session_list *session_get_list(void);
241 void session_list_wait_empty(void);
242
243 bool session_access_ok(struct ltt_session *session, uid_t uid);
244
245 int session_reset_rotation_state(struct ltt_session *session,
246 enum lttng_rotation_state result);
247
248 /* Create a new trace chunk object from the session's configuration. */
249 struct lttng_trace_chunk *session_create_new_trace_chunk(
250 const struct ltt_session *session,
251 const struct consumer_output *consumer_output_override,
252 const char *session_base_path_override,
253 const char *chunk_name_override);
254
255 /*
256 * Set `new_trace_chunk` as the session's current trace chunk. A reference
257 * to `new_trace_chunk` is acquired by the session. The chunk is created
258 * on remote peers (consumer and relay daemons).
259 *
260 * A reference to the session's current trace chunk is returned through
261 * `current_session_trace_chunk` on success.
262 */
263 int session_set_trace_chunk(struct ltt_session *session,
264 struct lttng_trace_chunk *new_trace_chunk,
265 struct lttng_trace_chunk **current_session_trace_chunk);
266
267 /*
268 * Close a chunk on the remote peers of a session. Has no effect on the
269 * ltt_session itself.
270 */
271 int session_close_trace_chunk(struct ltt_session *session,
272 struct lttng_trace_chunk *trace_chunk,
273 enum lttng_trace_chunk_command_type close_command,
274 char *path);
275
276 /* Open a packet in all channels of a given session. */
277 enum lttng_error_code session_open_packets(struct ltt_session *session);
278
279 bool session_output_supports_trace_chunks(const struct ltt_session *session);
280
281 #endif /* _LTT_SESSION_H */
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