883a265545e6965e2a82286cbcb6592d9781168c
[lttng-tools.git] / src / bin / lttng-sessiond / session.h
1 /*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
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.
7 *
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.
12 *
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.
16 */
17
18 #ifndef _LTT_SESSION_H
19 #define _LTT_SESSION_H
20
21 #include <limits.h>
22 #include <stdbool.h>
23 #include <urcu/list.h>
24
25 #include <common/hashtable/hashtable.h>
26 #include <common/dynamic-array.h>
27 #include <lttng/rotation.h>
28 #include <lttng/location.h>
29 #include <lttng/lttng-error.h>
30
31 #include "snapshot.h"
32 #include "trace-kernel.h"
33 #include "consumer.h"
34
35 struct ltt_ust_session;
36
37 typedef void (*ltt_session_destroy_notifier)(const struct ltt_session *session,
38 void *user_data);
39 typedef void (*ltt_session_clear_notifier)(const struct ltt_session *session,
40 void *user_data);
41
42 /*
43 * Tracing session list
44 *
45 * Statically declared in session.c and can be accessed by using
46 * session_get_list() function that returns the pointer to the list.
47 */
48 struct ltt_session_list {
49 /*
50 * This lock protects any read/write access to the list and
51 * next_uuid. All public functions in session.c acquire this
52 * lock and release it before returning. If none of those
53 * functions are used, the lock MUST be acquired in order to
54 * iterate or/and do any actions on that list.
55 */
56 pthread_mutex_t lock;
57 /*
58 * This condition variable is signaled on every removal from
59 * the session list.
60 */
61 pthread_cond_t removal_cond;
62
63 /*
64 * Session unique ID generator. The session list lock MUST be
65 * upon update and read of this counter.
66 */
67 uint64_t next_uuid;
68
69 /* Linked list head */
70 struct cds_list_head head;
71 };
72
73 /*
74 * This data structure contains information needed to identify a tracing
75 * session for both LTTng and UST.
76 */
77 struct ltt_session {
78 char name[NAME_MAX];
79 bool has_auto_generated_name;
80 bool name_contains_creation_time;
81 char hostname[HOST_NAME_MAX]; /* Local hostname. */
82 /* Path of the last closed chunk. */
83 char last_chunk_path[LTTNG_PATH_MAX];
84 time_t creation_time;
85 struct ltt_kernel_session *kernel_session;
86 struct ltt_ust_session *ust_session;
87 struct urcu_ref ref;
88 /*
89 * Protect any read/write on this session data structure. This lock must be
90 * acquired *before* using any public functions declared below. Use
91 * session_lock() and session_unlock() for that.
92 */
93 pthread_mutex_t lock;
94 struct cds_list_head list;
95 uint64_t id; /* session unique identifier */
96 /* Indicates if the session has been added to the session list and ht.*/
97 bool published;
98 /* Indicates if a destroy command has been applied to this session. */
99 bool destroyed;
100 /* UID/GID of the user owning the session */
101 uid_t uid;
102 gid_t gid;
103 /*
104 * Network session handle. A value of 0 means that there is no remote
105 * session established.
106 */
107 uint64_t net_handle;
108 /*
109 * This consumer is only set when the create_session_uri call is made.
110 * This contains the temporary information for a consumer output. Upon
111 * creation of the UST or kernel session, this consumer, if available, is
112 * copied into those sessions.
113 */
114 struct consumer_output *consumer;
115 /*
116 * Indicates whether or not the user has specified an output directory
117 * or if it was configured using the default configuration.
118 */
119 bool has_user_specified_directory;
120 /* Did at least ONE start command has been triggered?. */
121 unsigned int has_been_started:1;
122 /*
123 * Is the session active? Start trace command sets this to 1 and the stop
124 * command reset it to 0.
125 */
126 unsigned int active:1;
127
128 /* Snapshot representation in a session. */
129 struct snapshot snapshot;
130 /* Indicate if the session has to output the traces or not. */
131 unsigned int output_traces;
132 /*
133 * This session is in snapshot mode. This means that channels enabled
134 * will be set in overwrite mode by default and must be in mmap
135 * output mode. Note that snapshots can be taken on a session that
136 * is not in "snapshot_mode". This parameter only affects channel
137 * creation defaults.
138 */
139 unsigned int snapshot_mode;
140 /*
141 * A session that has channels that don't use 'mmap' output can't be
142 * used to capture snapshots. This is set to true whenever a
143 * 'splice' kernel channel is enabled.
144 */
145 bool has_non_mmap_channel;
146 /*
147 * Timer set when the session is created for live reading.
148 */
149 unsigned int live_timer;
150 /*
151 * Path where to keep the shared memory files.
152 */
153 char shm_path[PATH_MAX];
154 /*
155 * Node in ltt_sessions_ht_by_id.
156 */
157 struct lttng_ht_node_u64 node;
158 /*
159 * Timer to check periodically if a relay and/or consumer has completed
160 * the last rotation.
161 */
162 bool rotation_pending_check_timer_enabled;
163 timer_t rotation_pending_check_timer;
164 /* Timer to periodically rotate a session. */
165 bool rotation_schedule_timer_enabled;
166 timer_t rotation_schedule_timer;
167 /* Value for periodic rotations, 0 if disabled. */
168 uint64_t rotate_timer_period;
169 /* Value for size-based rotations, 0 if disabled. */
170 uint64_t rotate_size;
171 /*
172 * Keep a state if this session was rotated after the last stop command.
173 * We only allow one rotation after a stop. At destroy, we also need to
174 * know if a rotation occurred since the last stop to rename the current
175 * chunk. After a stop followed by rotate, all subsequent clear
176 * (without prior start) will succeed, but will be effect-less.
177 */
178 bool rotated_after_last_stop;
179 /*
180 * Track whether the session was cleared after last stop. All subsequent
181 * clear (without prior start) will succeed, but will be effect-less. A
182 * subsequent rotate (without prior start) will return an error.
183 */
184 bool cleared_after_last_stop;
185 /*
186 * True if the session has had an explicit non-quiet rotation.
187 */
188 bool rotated;
189 /*
190 * Condition and trigger for size-based rotations.
191 */
192 struct lttng_condition *rotate_condition;
193 struct lttng_trigger *rotate_trigger;
194 LTTNG_OPTIONAL(uint64_t) most_recent_chunk_id;
195 struct lttng_trace_chunk *current_trace_chunk;
196 struct lttng_trace_chunk *chunk_being_archived;
197 /* Current state of a rotation. */
198 enum lttng_rotation_state rotation_state;
199 bool quiet_rotation;
200 char *last_archived_chunk_name;
201 LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id;
202 struct lttng_dynamic_array destroy_notifiers;
203 struct lttng_dynamic_array clear_notifiers;
204 /* Session base path override. Set non-null. */
205 char *base_path;
206 };
207
208 /* Prototypes */
209 enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
210 struct ltt_session **out_session);
211 void session_lock(struct ltt_session *session);
212 void session_lock_list(void);
213 int session_trylock_list(void);
214 void session_unlock(struct ltt_session *session);
215 void session_unlock_list(void);
216
217 void session_destroy(struct ltt_session *session);
218 int session_add_destroy_notifier(struct ltt_session *session,
219 ltt_session_destroy_notifier notifier, void *user_data);
220
221 int session_add_clear_notifier(struct ltt_session *session,
222 ltt_session_clear_notifier notifier, void *user_data);
223 void session_notify_clear(struct ltt_session *session);
224
225 bool session_get(struct ltt_session *session);
226 void session_put(struct ltt_session *session);
227
228 enum consumer_dst_type session_get_consumer_destination_type(
229 const struct ltt_session *session);
230 const char *session_get_net_consumer_hostname(
231 const struct ltt_session *session);
232 void session_get_net_consumer_ports(
233 const struct ltt_session *session,
234 uint16_t *control_port, uint16_t *data_port);
235 struct lttng_trace_archive_location *session_get_trace_archive_location(
236 const struct ltt_session *session);
237
238 struct ltt_session *session_find_by_name(const char *name);
239 struct ltt_session *session_find_by_id(uint64_t id);
240
241 struct ltt_session_list *session_get_list(void);
242 void session_list_wait_empty(void);
243
244 int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
245
246 int session_reset_rotation_state(struct ltt_session *session,
247 enum lttng_rotation_state result);
248
249 /* Create a new trace chunk object from the session's configuration. */
250 struct lttng_trace_chunk *session_create_new_trace_chunk(
251 const struct ltt_session *session,
252 const struct consumer_output *consumer_output_override,
253 const char *session_base_path_override,
254 const char *chunk_name_override);
255
256 /*
257 * Set `new_trace_chunk` as the session's current trace chunk. A reference
258 * to `new_trace_chunk` is acquired by the session. The chunk is created
259 * on remote peers (consumer and relay daemons).
260 *
261 * A reference to the session's current trace chunk is returned through
262 * `current_session_trace_chunk` on success.
263 */
264 int session_set_trace_chunk(struct ltt_session *session,
265 struct lttng_trace_chunk *new_trace_chunk,
266 struct lttng_trace_chunk **current_session_trace_chunk);
267
268 /*
269 * Close a chunk on the remote peers of a session. Has no effect on the
270 * ltt_session itself.
271 */
272 int session_close_trace_chunk(struct ltt_session *session,
273 struct lttng_trace_chunk *trace_chunk,
274 enum lttng_trace_chunk_command_type close_command,
275 char *path);
276
277 bool session_output_supports_trace_chunks(const struct ltt_session *session);
278
279 #endif /* _LTT_SESSION_H */
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