Sessiond timer thread
[lttng-tools.git] / src / bin / lttng-sessiond / session.h
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91d76f53 1/*
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2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
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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.
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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 *
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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.
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16 */
17
18#ifndef _LTT_SESSION_H
19#define _LTT_SESSION_H
20
73184835 21#include <limits.h>
20fe2104 22#include <urcu/list.h>
d4a2a84a 23
6dc3064a 24#include <common/hashtable/hashtable.h>
db66e574 25#include <lttng/rotation.h>
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26
27#include "snapshot.h"
00187dd4 28#include "trace-kernel.h"
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29
30struct ltt_ust_session;
00187dd4 31
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32/*
33 * Tracing session list
34 *
35 * Statically declared in session.c and can be accessed by using
54d01ffb 36 * session_get_list() function that returns the pointer to the list.
b5541356 37 */
5b74c7b1 38struct ltt_session_list {
b5541356 39 /*
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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.
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45 */
46 pthread_mutex_t lock;
6c9cc2ab 47
b5541356 48 /*
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49 * Session unique ID generator. The session list lock MUST be
50 * upon update and read of this counter.
b5541356 51 */
d022620a 52 uint64_t next_uuid;
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53
54 /* Linked list head */
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55 struct cds_list_head head;
56};
57
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58/*
59 * This data structure contains information needed to identify a tracing
60 * session for both LTTng and UST.
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61 */
62struct ltt_session {
74babd95 63 char name[NAME_MAX];
73184835 64 char hostname[HOST_NAME_MAX]; /* Local hostname. */
20fe2104 65 struct ltt_kernel_session *kernel_session;
f6a9efaa 66 struct ltt_ust_session *ust_session;
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67 /*
68 * Protect any read/write on this session data structure. This lock must be
69 * acquired *before* using any public functions declared below. Use
54d01ffb 70 * session_lock() and session_unlock() for that.
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71 */
72 pthread_mutex_t lock;
73 struct cds_list_head list;
d022620a 74 uint64_t id; /* session unique identifier */
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75 /* UID/GID of the user owning the session */
76 uid_t uid;
77 gid_t gid;
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78 /*
79 * Network session handle. A value of 0 means that there is no remote
80 * session established.
81 */
82 uint64_t net_handle;
83 /*
84 * This consumer is only set when the create_session_uri call is made.
85 * This contains the temporary information for a consumer output. Upon
86 * creation of the UST or kernel session, this consumer, if available, is
87 * copied into those sessions.
88 */
89 struct consumer_output *consumer;
a4b92340 90
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91 /* Did at least ONE start command has been triggered?. */
92 unsigned int has_been_started:1;
93 /*
94 * Is the session active? Start trace command sets this to 1 and the stop
95 * command reset it to 0.
96 */
97 unsigned int active:1;
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98
99 /* Snapshot representation in a session. */
100 struct snapshot snapshot;
101 /* Indicate if the session has to output the traces or not. */
102 unsigned int output_traces;
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103 /*
104 * This session is in snapshot mode. This means that every channel enabled
105 * will be set in overwrite mode and mmap. It is considered exclusively for
106 * snapshot purposes.
107 */
108 unsigned int snapshot_mode;
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109 /*
110 * Timer set when the session is created for live reading.
111 */
d98ad589 112 unsigned int live_timer;
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113 /*
114 * Path where to keep the shared memory files.
115 */
116 char shm_path[PATH_MAX];
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117 /*
118 * Node in ltt_sessions_ht_by_id.
119 */
120 struct lttng_ht_node_u64 node;
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121 /* Number of session rotation for this session. */
122 uint64_t rotate_count;
123 /*
124 * Rotation is pending between the time it starts until the consumer has
125 * finished extracting the data. If the session uses a relay, data related
126 * to a rotation can still be in flight after that, see
127 * rotate_pending_relay.
128 */
129 bool rotate_pending;
130 /* Current status of a rotation. */
131 enum lttng_rotation_status rotation_status;
132 /*
133 * Number of channels waiting for a rotation.
134 * When this number reaches 0, we can handle the rename of the chunk
135 * folder and inform the client that the rotate is finished.
136 */
137 unsigned int nr_chan_rotate_pending;
138 struct {
139 /*
140 * When the rotation is in progress, the temporary path name is
141 * stored here. When the rotation is complete, the final path name
142 * is here and can be queried with the rotate_pending call.
143 */
144 char current_rotate_path[LTTNG_PATH_MAX];
145 /*
146 * The path where the consumer is currently writing after the first
147 * session rotation.
148 */
149 char active_tracing_path[LTTNG_PATH_MAX];
150 } rotation_chunk;
151 /*
152 * The timestamp of the beginning of the previous chunk. For the
153 * first chunk, this is the "lttng start" timestamp. For the
154 * subsequent ones, this copies the current_chunk_start_ts value when
155 * a new rotation starts. This value is used to set the name of a
156 * complete chunk directory, ex: "last_chunk_start_ts-now()".
157 */
158 time_t last_chunk_start_ts;
159 /*
160 * This is the timestamp when a new chunk starts. When a new rotation
161 * starts, we copy this value to last_chunk_start_ts and replace it
162 * with the current timestamp.
163 */
164 time_t current_chunk_start_ts;
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165};
166
167/* Prototypes */
dec56f6c 168int session_create(char *name, uid_t uid, gid_t gid);
271933a4 169int session_destroy(struct ltt_session *session);
6c9cc2ab 170
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171void session_lock(struct ltt_session *session);
172void session_lock_list(void);
173void session_unlock(struct ltt_session *session);
174void session_unlock_list(void);
6c9cc2ab 175
58a1a227 176struct ltt_session *session_find_by_name(const char *name);
23324029 177struct ltt_session *session_find_by_id(uint64_t id);
54d01ffb 178struct ltt_session_list *session_get_list(void);
5b74c7b1 179
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180int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
181
5b74c7b1 182#endif /* _LTT_SESSION_H */
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