Fix: perform local data pending before checking data pending with relayd
[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>
5c408ad8 22#include <stdbool.h>
20fe2104 23#include <urcu/list.h>
d4a2a84a 24
6dc3064a 25#include <common/hashtable/hashtable.h>
db66e574 26#include <lttng/rotation.h>
5d65beab 27#include <lttng/location.h>
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28
29#include "snapshot.h"
00187dd4 30#include "trace-kernel.h"
dd73d57b 31#include "consumer.h"
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32
33struct ltt_ust_session;
00187dd4 34
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35/*
36 * Tracing session list
37 *
38 * Statically declared in session.c and can be accessed by using
54d01ffb 39 * session_get_list() function that returns the pointer to the list.
b5541356 40 */
5b74c7b1 41struct ltt_session_list {
b5541356 42 /*
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43 * This lock protects any read/write access to the list and
44 * next_uuid. All public functions in session.c acquire this
45 * lock and release it before returning. If none of those
46 * functions are used, the lock MUST be acquired in order to
47 * iterate or/and do any actions on that list.
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48 */
49 pthread_mutex_t lock;
6c9cc2ab 50
b5541356 51 /*
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52 * Session unique ID generator. The session list lock MUST be
53 * upon update and read of this counter.
b5541356 54 */
d022620a 55 uint64_t next_uuid;
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56
57 /* Linked list head */
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58 struct cds_list_head head;
59};
60
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61/*
62 * This data structure contains information needed to identify a tracing
63 * session for both LTTng and UST.
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64 */
65struct ltt_session {
74babd95 66 char name[NAME_MAX];
73184835 67 char hostname[HOST_NAME_MAX]; /* Local hostname. */
20fe2104 68 struct ltt_kernel_session *kernel_session;
f6a9efaa 69 struct ltt_ust_session *ust_session;
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70 /*
71 * Protect any read/write on this session data structure. This lock must be
72 * acquired *before* using any public functions declared below. Use
54d01ffb 73 * session_lock() and session_unlock() for that.
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74 */
75 pthread_mutex_t lock;
76 struct cds_list_head list;
d022620a 77 uint64_t id; /* session unique identifier */
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78 /* UID/GID of the user owning the session */
79 uid_t uid;
80 gid_t gid;
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81 /*
82 * Network session handle. A value of 0 means that there is no remote
83 * session established.
84 */
85 uint64_t net_handle;
86 /*
87 * This consumer is only set when the create_session_uri call is made.
88 * This contains the temporary information for a consumer output. Upon
89 * creation of the UST or kernel session, this consumer, if available, is
90 * copied into those sessions.
91 */
92 struct consumer_output *consumer;
a4b92340 93
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94 /* Did at least ONE start command has been triggered?. */
95 unsigned int has_been_started:1;
96 /*
97 * Is the session active? Start trace command sets this to 1 and the stop
98 * command reset it to 0.
99 */
100 unsigned int active:1;
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101
102 /* Snapshot representation in a session. */
103 struct snapshot snapshot;
104 /* Indicate if the session has to output the traces or not. */
105 unsigned int output_traces;
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106 /*
107 * This session is in snapshot mode. This means that every channel enabled
108 * will be set in overwrite mode and mmap. It is considered exclusively for
109 * snapshot purposes.
110 */
111 unsigned int snapshot_mode;
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112 /*
113 * Timer set when the session is created for live reading.
114 */
d98ad589 115 unsigned int live_timer;
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116 /*
117 * Path where to keep the shared memory files.
118 */
119 char shm_path[PATH_MAX];
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120 /*
121 * Node in ltt_sessions_ht_by_id.
122 */
123 struct lttng_ht_node_u64 node;
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124 /*
125 * The current archive id corresponds to the number of session rotations
126 * that have occured for this session. The archive id
127 * is used to tag the "generation" of a stream. This tag allows the
128 * consumer and relay daemons to track when a given stream was created
129 * during the lifetime of a session.
130 *
131 * For instance, if a stream is created after a session rotation was
132 * launched, the consumer and relay daemons must not check its position
133 * to determine if that specific session rotation was completed. It is
134 * implicitly "completed" since the stream appeared _after_ the session
135 * rotation was initiated.
136 */
137 uint64_t current_archive_id;
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138 /*
139 * Rotation is pending between the time it starts until the consumer has
140 * finished extracting the data. If the session uses a relay, data related
141 * to a rotation can still be in flight after that, see
142 * rotate_pending_relay.
143 */
144 bool rotate_pending;
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145 /*
146 * True until the relay has finished the rotation of all the streams.
147 */
148 bool rotate_pending_relay;
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149 /* Current state of a rotation. */
150 enum lttng_rotation_state rotation_state;
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151 /*
152 * Number of channels waiting for a rotation.
153 * When this number reaches 0, we can handle the rename of the chunk
154 * folder and inform the client that the rotate is finished.
155 */
156 unsigned int nr_chan_rotate_pending;
157 struct {
158 /*
159 * When the rotation is in progress, the temporary path name is
160 * stored here. When the rotation is complete, the final path name
161 * is here and can be queried with the rotate_pending call.
162 */
163 char current_rotate_path[LTTNG_PATH_MAX];
164 /*
165 * The path where the consumer is currently writing after the first
166 * session rotation.
167 */
168 char active_tracing_path[LTTNG_PATH_MAX];
169 } rotation_chunk;
170 /*
171 * The timestamp of the beginning of the previous chunk. For the
172 * first chunk, this is the "lttng start" timestamp. For the
173 * subsequent ones, this copies the current_chunk_start_ts value when
174 * a new rotation starts. This value is used to set the name of a
175 * complete chunk directory, ex: "last_chunk_start_ts-now()".
176 */
177 time_t last_chunk_start_ts;
178 /*
179 * This is the timestamp when a new chunk starts. When a new rotation
180 * starts, we copy this value to last_chunk_start_ts and replace it
181 * with the current timestamp.
182 */
183 time_t current_chunk_start_ts;
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184 /*
185 * Timer to check periodically if a relay has completed the last
186 * rotation.
187 */
188 bool rotate_relay_pending_timer_enabled;
189 timer_t rotate_relay_pending_timer;
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190 /* Timer to periodically rotate a session. */
191 bool rotate_timer_enabled;
192 timer_t rotate_timer;
66ea93b1 193 /* Value for periodic rotations, 0 if disabled. */
259c2674 194 uint64_t rotate_timer_period;
66ea93b1 195 /* Value for size-based rotations, 0 if disabled. */
259c2674 196 uint64_t rotate_size;
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197 /*
198 * Keep a state if this session was rotated after the last stop command.
199 * We only allow one rotation after a stop. At destroy, we also need to
200 * know if a rotation occured since the last stop to rename the current
201 * chunk.
202 */
203 bool rotated_after_last_stop;
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204 /*
205 * Condition and trigger for size-based rotations.
206 */
207 struct lttng_condition *rotate_condition;
208 struct lttng_trigger *rotate_trigger;
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209};
210
211/* Prototypes */
dec56f6c 212int session_create(char *name, uid_t uid, gid_t gid);
271933a4 213int session_destroy(struct ltt_session *session);
6c9cc2ab 214
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215void session_lock(struct ltt_session *session);
216void session_lock_list(void);
71e0a100 217int session_trylock_list(void);
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218void session_unlock(struct ltt_session *session);
219void session_unlock_list(void);
6c9cc2ab 220
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221enum consumer_dst_type session_get_consumer_destination_type(
222 const struct ltt_session *session);
223const char *session_get_net_consumer_hostname(
224 const struct ltt_session *session);
225void session_get_net_consumer_ports(
226 const struct ltt_session *session,
227 uint16_t *control_port, uint16_t *data_port);
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228struct lttng_trace_archive_location *session_get_trace_archive_location(
229 struct ltt_session *session);
dd73d57b 230
58a1a227 231struct ltt_session *session_find_by_name(const char *name);
23324029 232struct ltt_session *session_find_by_id(uint64_t id);
54d01ffb 233struct ltt_session_list *session_get_list(void);
5b74c7b1 234
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235int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
236
5b74c7b1 237#endif /* _LTT_SESSION_H */
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