03d90c2c5ae8041b58572eb8329321bdfe303a74
[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
40 /*
41 * Tracing session list
42 *
43 * Statically declared in session.c and can be accessed by using
44 * session_get_list() function that returns the pointer to the list.
45 */
46 struct ltt_session_list {
47 /*
48 * This lock protects any read/write access to the list and
49 * next_uuid. All public functions in session.c acquire this
50 * lock and release it before returning. If none of those
51 * functions are used, the lock MUST be acquired in order to
52 * iterate or/and do any actions on that list.
53 */
54 pthread_mutex_t lock;
55 /*
56 * This condition variable is signaled on every removal from
57 * the session list.
58 */
59 pthread_cond_t removal_cond;
60
61 /*
62 * Session unique ID generator. The session list lock MUST be
63 * upon update and read of this counter.
64 */
65 uint64_t next_uuid;
66
67 /* Linked list head */
68 struct cds_list_head head;
69 };
70
71 /*
72 * This data structure contains information needed to identify a tracing
73 * session for both LTTng and UST.
74 */
75 struct ltt_session {
76 char name[NAME_MAX];
77 bool has_auto_generated_name;
78 char hostname[HOST_NAME_MAX]; /* Local hostname. */
79 time_t creation_time;
80 struct ltt_kernel_session *kernel_session;
81 struct ltt_ust_session *ust_session;
82 struct urcu_ref ref;
83 /*
84 * Protect any read/write on this session data structure. This lock must be
85 * acquired *before* using any public functions declared below. Use
86 * session_lock() and session_unlock() for that.
87 */
88 pthread_mutex_t lock;
89 struct cds_list_head list;
90 uint64_t id; /* session unique identifier */
91 /* Indicates if the session has been added to the session list and ht.*/
92 bool published;
93 /* Indicates if a destroy command has been applied to this session. */
94 bool destroyed;
95 /* UID/GID of the user owning the session */
96 uid_t uid;
97 gid_t gid;
98 /*
99 * Network session handle. A value of 0 means that there is no remote
100 * session established.
101 */
102 uint64_t net_handle;
103 /*
104 * This consumer is only set when the create_session_uri call is made.
105 * This contains the temporary information for a consumer output. Upon
106 * creation of the UST or kernel session, this consumer, if available, is
107 * copied into those sessions.
108 */
109 struct consumer_output *consumer;
110 /*
111 * Indicates whether or not the user has specified an output directory
112 * or if it was configured using the default configuration.
113 */
114 bool has_user_specified_directory;
115 /* Did at least ONE start command has been triggered?. */
116 unsigned int has_been_started:1;
117 /*
118 * Is the session active? Start trace command sets this to 1 and the stop
119 * command reset it to 0.
120 */
121 unsigned int active:1;
122
123 /* Snapshot representation in a session. */
124 struct snapshot snapshot;
125 /* Indicate if the session has to output the traces or not. */
126 unsigned int output_traces;
127 /*
128 * This session is in snapshot mode. This means that channels enabled
129 * will be set in overwrite mode by default and must be in mmap
130 * output mode. Note that snapshots can be taken on a session that
131 * is not in "snapshot_mode". This parameter only affects channel
132 * creation defaults.
133 */
134 unsigned int snapshot_mode;
135 /*
136 * A session that has channels that don't use 'mmap' output can't be
137 * used to capture snapshots. This is set to true whenever a
138 * 'splice' kernel channel is enabled.
139 */
140 bool has_non_mmap_channel;
141 /*
142 * Timer set when the session is created for live reading.
143 */
144 unsigned int live_timer;
145 /*
146 * Path where to keep the shared memory files.
147 */
148 char shm_path[PATH_MAX];
149 /*
150 * Node in ltt_sessions_ht_by_id.
151 */
152 struct lttng_ht_node_u64 node;
153 /*
154 * Timer to check periodically if a relay and/or consumer has completed
155 * the last rotation.
156 */
157 bool rotation_pending_check_timer_enabled;
158 timer_t rotation_pending_check_timer;
159 /* Timer to periodically rotate a session. */
160 bool rotation_schedule_timer_enabled;
161 timer_t rotation_schedule_timer;
162 /* Value for periodic rotations, 0 if disabled. */
163 uint64_t rotate_timer_period;
164 /* Value for size-based rotations, 0 if disabled. */
165 uint64_t rotate_size;
166 /*
167 * Keep a state if this session was rotated after the last stop command.
168 * We only allow one rotation after a stop. At destroy, we also need to
169 * know if a rotation occurred since the last stop to rename the current
170 * chunk.
171 */
172 bool rotated_after_last_stop;
173 /*
174 * Condition and trigger for size-based rotations.
175 */
176 struct lttng_condition *rotate_condition;
177 struct lttng_trigger *rotate_trigger;
178 LTTNG_OPTIONAL(uint64_t) most_recent_chunk_id;
179 struct lttng_trace_chunk *current_trace_chunk;
180 struct lttng_trace_chunk *chunk_being_archived;
181 /* Current state of a rotation. */
182 enum lttng_rotation_state rotation_state;
183 char *last_archived_chunk_name;
184 LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id;
185 struct lttng_dynamic_array destroy_notifiers;
186 };
187
188 /* Prototypes */
189 enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
190 struct ltt_session **out_session);
191 void session_lock(struct ltt_session *session);
192 void session_lock_list(void);
193 int session_trylock_list(void);
194 void session_unlock(struct ltt_session *session);
195 void session_unlock_list(void);
196
197 void session_destroy(struct ltt_session *session);
198 int session_add_destroy_notifier(struct ltt_session *session,
199 ltt_session_destroy_notifier notifier, void *user_data);
200
201 bool session_get(struct ltt_session *session);
202 void session_put(struct ltt_session *session);
203
204 enum consumer_dst_type session_get_consumer_destination_type(
205 const struct ltt_session *session);
206 const char *session_get_net_consumer_hostname(
207 const struct ltt_session *session);
208 void session_get_net_consumer_ports(
209 const struct ltt_session *session,
210 uint16_t *control_port, uint16_t *data_port);
211 struct lttng_trace_archive_location *session_get_trace_archive_location(
212 const struct ltt_session *session);
213
214 struct ltt_session *session_find_by_name(const char *name);
215 struct ltt_session *session_find_by_id(uint64_t id);
216
217 struct ltt_session_list *session_get_list(void);
218 void session_list_wait_empty(void);
219
220 int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
221
222 int session_reset_rotation_state(struct ltt_session *session,
223 enum lttng_rotation_state result);
224
225 /* Create a new trace chunk object from the session's configuration. */
226 struct lttng_trace_chunk *session_create_new_trace_chunk(
227 const struct ltt_session *session,
228 const struct consumer_output *consumer_output_override,
229 const char *session_base_path_override,
230 const char *chunk_name_override);
231
232 /*
233 * Set `new_trace_chunk` as the session's current trace chunk. A reference
234 * to `new_trace_chunk` is acquired by the session. The chunk is created
235 * on remote peers (consumer and relay daemons).
236 *
237 * A reference to the session's current trace chunk is returned through
238 * `current_session_trace_chunk` on success.
239 */
240 int session_set_trace_chunk(struct ltt_session *session,
241 struct lttng_trace_chunk *new_trace_chunk,
242 struct lttng_trace_chunk **current_session_trace_chunk);
243
244 /*
245 * Close a chunk on the remote peers of a session. Has no effect on the
246 * ltt_session itself.
247 */
248 int session_close_trace_chunk(const struct ltt_session *session,
249 struct lttng_trace_chunk *trace_chunk,
250 const enum lttng_trace_chunk_command_type *close_command);
251
252 #endif /* _LTT_SESSION_H */
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