Extend the rotation API to provide network trace archive locations
[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 <lttng/rotation.h>
27
28 #include "snapshot.h"
29 #include "trace-kernel.h"
30 #include "consumer.h"
31
32 struct ltt_ust_session;
33
34 /*
35 * Tracing session list
36 *
37 * Statically declared in session.c and can be accessed by using
38 * session_get_list() function that returns the pointer to the list.
39 */
40 struct ltt_session_list {
41 /*
42 * This lock protects any read/write access to the list and
43 * next_uuid. All public functions in session.c acquire this
44 * lock and release it before returning. If none of those
45 * functions are used, the lock MUST be acquired in order to
46 * iterate or/and do any actions on that list.
47 */
48 pthread_mutex_t lock;
49
50 /*
51 * Session unique ID generator. The session list lock MUST be
52 * upon update and read of this counter.
53 */
54 uint64_t next_uuid;
55
56 /* Linked list head */
57 struct cds_list_head head;
58 };
59
60 /*
61 * This data structure contains information needed to identify a tracing
62 * session for both LTTng and UST.
63 */
64 struct ltt_session {
65 char name[NAME_MAX];
66 char hostname[HOST_NAME_MAX]; /* Local hostname. */
67 struct ltt_kernel_session *kernel_session;
68 struct ltt_ust_session *ust_session;
69 /*
70 * Protect any read/write on this session data structure. This lock must be
71 * acquired *before* using any public functions declared below. Use
72 * session_lock() and session_unlock() for that.
73 */
74 pthread_mutex_t lock;
75 struct cds_list_head list;
76 uint64_t id; /* session unique identifier */
77 /* UID/GID of the user owning the session */
78 uid_t uid;
79 gid_t gid;
80 /*
81 * Network session handle. A value of 0 means that there is no remote
82 * session established.
83 */
84 uint64_t net_handle;
85 /*
86 * This consumer is only set when the create_session_uri call is made.
87 * This contains the temporary information for a consumer output. Upon
88 * creation of the UST or kernel session, this consumer, if available, is
89 * copied into those sessions.
90 */
91 struct consumer_output *consumer;
92
93 /* Did at least ONE start command has been triggered?. */
94 unsigned int has_been_started:1;
95 /*
96 * Is the session active? Start trace command sets this to 1 and the stop
97 * command reset it to 0.
98 */
99 unsigned int active:1;
100
101 /* Snapshot representation in a session. */
102 struct snapshot snapshot;
103 /* Indicate if the session has to output the traces or not. */
104 unsigned int output_traces;
105 /*
106 * This session is in snapshot mode. This means that every channel enabled
107 * will be set in overwrite mode and mmap. It is considered exclusively for
108 * snapshot purposes.
109 */
110 unsigned int snapshot_mode;
111 /*
112 * Timer set when the session is created for live reading.
113 */
114 unsigned int live_timer;
115 /*
116 * Path where to keep the shared memory files.
117 */
118 char shm_path[PATH_MAX];
119 /*
120 * Node in ltt_sessions_ht_by_id.
121 */
122 struct lttng_ht_node_u64 node;
123 /* Number of session rotation for this session. */
124 uint64_t rotate_count;
125 /*
126 * Rotation is pending between the time it starts until the consumer has
127 * finished extracting the data. If the session uses a relay, data related
128 * to a rotation can still be in flight after that, see
129 * rotate_pending_relay.
130 */
131 bool rotate_pending;
132 /*
133 * True until the relay has finished the rotation of all the streams.
134 */
135 bool rotate_pending_relay;
136 /* Current state of a rotation. */
137 enum lttng_rotation_state rotation_state;
138 /*
139 * Number of channels waiting for a rotation.
140 * When this number reaches 0, we can handle the rename of the chunk
141 * folder and inform the client that the rotate is finished.
142 */
143 unsigned int nr_chan_rotate_pending;
144 struct {
145 /*
146 * When the rotation is in progress, the temporary path name is
147 * stored here. When the rotation is complete, the final path name
148 * is here and can be queried with the rotate_pending call.
149 */
150 char current_rotate_path[LTTNG_PATH_MAX];
151 /*
152 * The path where the consumer is currently writing after the first
153 * session rotation.
154 */
155 char active_tracing_path[LTTNG_PATH_MAX];
156 } rotation_chunk;
157 /*
158 * The timestamp of the beginning of the previous chunk. For the
159 * first chunk, this is the "lttng start" timestamp. For the
160 * subsequent ones, this copies the current_chunk_start_ts value when
161 * a new rotation starts. This value is used to set the name of a
162 * complete chunk directory, ex: "last_chunk_start_ts-now()".
163 */
164 time_t last_chunk_start_ts;
165 /*
166 * This is the timestamp when a new chunk starts. When a new rotation
167 * starts, we copy this value to last_chunk_start_ts and replace it
168 * with the current timestamp.
169 */
170 time_t current_chunk_start_ts;
171 /*
172 * Timer to check periodically if a relay has completed the last
173 * rotation.
174 */
175 bool rotate_relay_pending_timer_enabled;
176 timer_t rotate_relay_pending_timer;
177 /* Timer to periodically rotate a session. */
178 bool rotate_timer_enabled;
179 timer_t rotate_timer;
180 uint64_t rotate_timer_period;
181 /* Value for size-based rotation, 0 if disabled. */
182 uint64_t rotate_size;
183 /*
184 * Keep a state if this session was rotated after the last stop command.
185 * We only allow one rotation after a stop. At destroy, we also need to
186 * know if a rotation occured since the last stop to rename the current
187 * chunk.
188 */
189 bool rotated_after_last_stop;
190 /*
191 * Condition and trigger for size-based rotations.
192 */
193 struct lttng_condition *rotate_condition;
194 struct lttng_trigger *rotate_trigger;
195 };
196
197 /* Prototypes */
198 int session_create(char *name, uid_t uid, gid_t gid);
199 int session_destroy(struct ltt_session *session);
200
201 void session_lock(struct ltt_session *session);
202 void session_lock_list(void);
203 void session_unlock(struct ltt_session *session);
204 void session_unlock_list(void);
205
206 enum consumer_dst_type session_get_consumer_destination_type(
207 const struct ltt_session *session);
208 const char *session_get_net_consumer_hostname(
209 const struct ltt_session *session);
210 void session_get_net_consumer_ports(
211 const struct ltt_session *session,
212 uint16_t *control_port, uint16_t *data_port);
213
214 struct ltt_session *session_find_by_name(const char *name);
215 struct ltt_session *session_find_by_id(uint64_t id);
216 struct ltt_session_list *session_get_list(void);
217
218 int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
219
220 #endif /* _LTT_SESSION_H */
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