Fix: release reference to ltt_session on error instead of free()
[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;
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50 /*
51 * This condition variable is signaled on every removal from
52 * the session list.
53 */
54 pthread_cond_t removal_cond;
6c9cc2ab 55
b5541356 56 /*
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57 * Session unique ID generator. The session list lock MUST be
58 * upon update and read of this counter.
b5541356 59 */
d022620a 60 uint64_t next_uuid;
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61
62 /* Linked list head */
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63 struct cds_list_head head;
64};
65
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66/*
67 * This data structure contains information needed to identify a tracing
68 * session for both LTTng and UST.
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69 */
70struct ltt_session {
74babd95 71 char name[NAME_MAX];
73184835 72 char hostname[HOST_NAME_MAX]; /* Local hostname. */
20fe2104 73 struct ltt_kernel_session *kernel_session;
f6a9efaa 74 struct ltt_ust_session *ust_session;
e32d7f27 75 struct urcu_ref ref;
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76 /*
77 * Protect any read/write on this session data structure. This lock must be
78 * acquired *before* using any public functions declared below. Use
54d01ffb 79 * session_lock() and session_unlock() for that.
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80 */
81 pthread_mutex_t lock;
82 struct cds_list_head list;
d022620a 83 uint64_t id; /* session unique identifier */
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84 /* Indicates if the session has been added to the session list and ht.*/
85 bool published;
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86 /* Indicates if a destroy command has been applied to this session. */
87 bool destroyed;
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88 /* UID/GID of the user owning the session */
89 uid_t uid;
90 gid_t gid;
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91 /*
92 * Network session handle. A value of 0 means that there is no remote
93 * session established.
94 */
95 uint64_t net_handle;
96 /*
97 * This consumer is only set when the create_session_uri call is made.
98 * This contains the temporary information for a consumer output. Upon
99 * creation of the UST or kernel session, this consumer, if available, is
100 * copied into those sessions.
101 */
102 struct consumer_output *consumer;
a4b92340 103
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104 /* Did at least ONE start command has been triggered?. */
105 unsigned int has_been_started:1;
106 /*
107 * Is the session active? Start trace command sets this to 1 and the stop
108 * command reset it to 0.
109 */
110 unsigned int active:1;
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111
112 /* Snapshot representation in a session. */
113 struct snapshot snapshot;
114 /* Indicate if the session has to output the traces or not. */
115 unsigned int output_traces;
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116 /*
117 * This session is in snapshot mode. This means that every channel enabled
118 * will be set in overwrite mode and mmap. It is considered exclusively for
119 * snapshot purposes.
120 */
121 unsigned int snapshot_mode;
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122 /*
123 * Timer set when the session is created for live reading.
124 */
d98ad589 125 unsigned int live_timer;
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126 /*
127 * Path where to keep the shared memory files.
128 */
129 char shm_path[PATH_MAX];
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130 /*
131 * Node in ltt_sessions_ht_by_id.
132 */
133 struct lttng_ht_node_u64 node;
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134 /*
135 * The current archive id corresponds to the number of session rotations
a9577b76 136 * that have occurred for this session. The archive id
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137 * is used to tag the "generation" of a stream. This tag allows the
138 * consumer and relay daemons to track when a given stream was created
139 * during the lifetime of a session.
140 *
141 * For instance, if a stream is created after a session rotation was
142 * launched, the consumer and relay daemons must not check its position
143 * to determine if that specific session rotation was completed. It is
144 * implicitly "completed" since the stream appeared _after_ the session
145 * rotation was initiated.
146 */
147 uint64_t current_archive_id;
db66e574 148 /*
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149 * Rotation is considered pending between the time it is launched up
150 * until the moment when the data has been writen at the destination
151 * and the trace archive has been renamed.
152 *
153 * When tracing locally, only 'rotation_pending_local' is used since
154 * no remote checks are needed. However, when tracing to a relay daemon,
155 * a second check is needed to ensure that the data has been
156 * commited at the remote destination.
5c408ad8 157 */
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158 bool rotation_pending_local;
159 bool rotation_pending_relay;
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160 /* Current state of a rotation. */
161 enum lttng_rotation_state rotation_state;
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162 struct {
163 /*
164 * When the rotation is in progress, the temporary path name is
165 * stored here. When the rotation is complete, the final path name
166 * is here and can be queried with the rotate_pending call.
167 */
168 char current_rotate_path[LTTNG_PATH_MAX];
169 /*
170 * The path where the consumer is currently writing after the first
171 * session rotation.
172 */
173 char active_tracing_path[LTTNG_PATH_MAX];
174 } rotation_chunk;
175 /*
176 * The timestamp of the beginning of the previous chunk. For the
177 * first chunk, this is the "lttng start" timestamp. For the
178 * subsequent ones, this copies the current_chunk_start_ts value when
179 * a new rotation starts. This value is used to set the name of a
180 * complete chunk directory, ex: "last_chunk_start_ts-now()".
181 */
182 time_t last_chunk_start_ts;
183 /*
184 * This is the timestamp when a new chunk starts. When a new rotation
185 * starts, we copy this value to last_chunk_start_ts and replace it
186 * with the current timestamp.
187 */
188 time_t current_chunk_start_ts;
d88744a4 189 /*
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190 * Timer to check periodically if a relay and/or consumer has completed
191 * the last rotation.
d88744a4 192 */
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193 bool rotation_pending_check_timer_enabled;
194 timer_t rotation_pending_check_timer;
259c2674 195 /* Timer to periodically rotate a session. */
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196 bool rotation_schedule_timer_enabled;
197 timer_t rotation_schedule_timer;
66ea93b1 198 /* Value for periodic rotations, 0 if disabled. */
259c2674 199 uint64_t rotate_timer_period;
66ea93b1 200 /* Value for size-based rotations, 0 if disabled. */
259c2674 201 uint64_t rotate_size;
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202 /*
203 * Keep a state if this session was rotated after the last stop command.
204 * We only allow one rotation after a stop. At destroy, we also need to
a9577b76 205 * know if a rotation occurred since the last stop to rename the current
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206 * chunk.
207 */
208 bool rotated_after_last_stop;
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209 /*
210 * Condition and trigger for size-based rotations.
211 */
212 struct lttng_condition *rotate_condition;
213 struct lttng_trigger *rotate_trigger;
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214};
215
216/* Prototypes */
dec56f6c 217int session_create(char *name, uid_t uid, gid_t gid);
6c9cc2ab 218
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219void session_lock(struct ltt_session *session);
220void session_lock_list(void);
71e0a100 221int session_trylock_list(void);
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222void session_unlock(struct ltt_session *session);
223void session_unlock_list(void);
6c9cc2ab 224
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225void session_destroy(struct ltt_session *session);
226
227bool session_get(struct ltt_session *session);
228void session_put(struct ltt_session *session);
229
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230enum consumer_dst_type session_get_consumer_destination_type(
231 const struct ltt_session *session);
232const char *session_get_net_consumer_hostname(
233 const struct ltt_session *session);
234void session_get_net_consumer_ports(
235 const struct ltt_session *session,
236 uint16_t *control_port, uint16_t *data_port);
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237struct lttng_trace_archive_location *session_get_trace_archive_location(
238 struct ltt_session *session);
dd73d57b 239
58a1a227 240struct ltt_session *session_find_by_name(const char *name);
23324029 241struct ltt_session *session_find_by_id(uint64_t id);
99d688f2 242
54d01ffb 243struct ltt_session_list *session_get_list(void);
99d688f2 244void session_list_wait_empty(void);
5b74c7b1 245
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246int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
247
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248int session_reset_rotation_state(struct ltt_session *session,
249 enum lttng_rotation_state result);
250
5b74c7b1 251#endif /* _LTT_SESSION_H */
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