Cleanup: remove duplicated code in snapshot record command
[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>
82b69413 28#include <lttng/lttng-error.h>
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29
30#include "snapshot.h"
00187dd4 31#include "trace-kernel.h"
dd73d57b 32#include "consumer.h"
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33
34struct ltt_ust_session;
00187dd4 35
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36/*
37 * Tracing session list
38 *
39 * Statically declared in session.c and can be accessed by using
54d01ffb 40 * session_get_list() function that returns the pointer to the list.
b5541356 41 */
5b74c7b1 42struct ltt_session_list {
b5541356 43 /*
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44 * This lock protects any read/write access to the list and
45 * next_uuid. All public functions in session.c acquire this
46 * lock and release it before returning. If none of those
47 * functions are used, the lock MUST be acquired in order to
48 * iterate or/and do any actions on that list.
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49 */
50 pthread_mutex_t lock;
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51 /*
52 * This condition variable is signaled on every removal from
53 * the session list.
54 */
55 pthread_cond_t removal_cond;
6c9cc2ab 56
b5541356 57 /*
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58 * Session unique ID generator. The session list lock MUST be
59 * upon update and read of this counter.
b5541356 60 */
d022620a 61 uint64_t next_uuid;
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62
63 /* Linked list head */
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64 struct cds_list_head head;
65};
66
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67/*
68 * This data structure contains information needed to identify a tracing
69 * session for both LTTng and UST.
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70 */
71struct ltt_session {
74babd95 72 char name[NAME_MAX];
b178f53e 73 bool has_auto_generated_name;
73184835 74 char hostname[HOST_NAME_MAX]; /* Local hostname. */
b178f53e 75 time_t creation_time;
20fe2104 76 struct ltt_kernel_session *kernel_session;
f6a9efaa 77 struct ltt_ust_session *ust_session;
e32d7f27 78 struct urcu_ref ref;
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79 /*
80 * Protect any read/write on this session data structure. This lock must be
81 * acquired *before* using any public functions declared below. Use
54d01ffb 82 * session_lock() and session_unlock() for that.
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83 */
84 pthread_mutex_t lock;
85 struct cds_list_head list;
d022620a 86 uint64_t id; /* session unique identifier */
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87 /* Indicates if the session has been added to the session list and ht.*/
88 bool published;
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89 /* Indicates if a destroy command has been applied to this session. */
90 bool destroyed;
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91 /* UID/GID of the user owning the session */
92 uid_t uid;
93 gid_t gid;
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94 /*
95 * Network session handle. A value of 0 means that there is no remote
96 * session established.
97 */
98 uint64_t net_handle;
99 /*
100 * This consumer is only set when the create_session_uri call is made.
101 * This contains the temporary information for a consumer output. Upon
102 * creation of the UST or kernel session, this consumer, if available, is
103 * copied into those sessions.
104 */
105 struct consumer_output *consumer;
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106 /*
107 * Indicates whether or not the user has specified an output directory
108 * or if it was configured using the default configuration.
109 */
110 bool has_user_specified_directory;
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111 /* Did at least ONE start command has been triggered?. */
112 unsigned int has_been_started:1;
113 /*
114 * Is the session active? Start trace command sets this to 1 and the stop
115 * command reset it to 0.
116 */
117 unsigned int active:1;
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118
119 /* Snapshot representation in a session. */
120 struct snapshot snapshot;
121 /* Indicate if the session has to output the traces or not. */
122 unsigned int output_traces;
27babd3a 123 /*
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124 * This session is in snapshot mode. This means that channels enabled
125 * will be set in overwrite mode by default and must be in mmap
126 * output mode. Note that snapshots can be taken on a session that
127 * is not in "snapshot_mode". This parameter only affects channel
128 * creation defaults.
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129 */
130 unsigned int snapshot_mode;
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131 /*
132 * A session that has channels that don't use 'mmap' output can't be
133 * used to capture snapshots. This is set to true whenever a
134 * 'splice' kernel channel is enabled.
135 */
136 bool has_non_mmap_channel;
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137 /*
138 * Timer set when the session is created for live reading.
139 */
d98ad589 140 unsigned int live_timer;
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141 /*
142 * Path where to keep the shared memory files.
143 */
144 char shm_path[PATH_MAX];
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145 /*
146 * Node in ltt_sessions_ht_by_id.
147 */
148 struct lttng_ht_node_u64 node;
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149 /*
150 * The current archive id corresponds to the number of session rotations
a9577b76 151 * that have occurred for this session. The archive id
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152 * is used to tag the "generation" of a stream. This tag allows the
153 * consumer and relay daemons to track when a given stream was created
154 * during the lifetime of a session.
155 *
156 * For instance, if a stream is created after a session rotation was
157 * launched, the consumer and relay daemons must not check its position
158 * to determine if that specific session rotation was completed. It is
159 * implicitly "completed" since the stream appeared _after_ the session
160 * rotation was initiated.
161 */
162 uint64_t current_archive_id;
db66e574 163 /*
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164 * Rotation is considered pending between the time it is launched up
165 * until the moment when the data has been writen at the destination
166 * and the trace archive has been renamed.
167 *
168 * When tracing locally, only 'rotation_pending_local' is used since
169 * no remote checks are needed. However, when tracing to a relay daemon,
170 * a second check is needed to ensure that the data has been
171 * commited at the remote destination.
5c408ad8 172 */
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173 bool rotation_pending_local;
174 bool rotation_pending_relay;
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175 /* Current state of a rotation. */
176 enum lttng_rotation_state rotation_state;
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177 struct {
178 /*
179 * When the rotation is in progress, the temporary path name is
180 * stored here. When the rotation is complete, the final path name
181 * is here and can be queried with the rotate_pending call.
182 */
183 char current_rotate_path[LTTNG_PATH_MAX];
184 /*
185 * The path where the consumer is currently writing after the first
186 * session rotation.
187 */
188 char active_tracing_path[LTTNG_PATH_MAX];
189 } rotation_chunk;
190 /*
191 * The timestamp of the beginning of the previous chunk. For the
192 * first chunk, this is the "lttng start" timestamp. For the
193 * subsequent ones, this copies the current_chunk_start_ts value when
194 * a new rotation starts. This value is used to set the name of a
195 * complete chunk directory, ex: "last_chunk_start_ts-now()".
196 */
197 time_t last_chunk_start_ts;
198 /*
199 * This is the timestamp when a new chunk starts. When a new rotation
200 * starts, we copy this value to last_chunk_start_ts and replace it
201 * with the current timestamp.
202 */
203 time_t current_chunk_start_ts;
d88744a4 204 /*
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205 * Timer to check periodically if a relay and/or consumer has completed
206 * the last rotation.
d88744a4 207 */
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208 bool rotation_pending_check_timer_enabled;
209 timer_t rotation_pending_check_timer;
259c2674 210 /* Timer to periodically rotate a session. */
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211 bool rotation_schedule_timer_enabled;
212 timer_t rotation_schedule_timer;
66ea93b1 213 /* Value for periodic rotations, 0 if disabled. */
259c2674 214 uint64_t rotate_timer_period;
66ea93b1 215 /* Value for size-based rotations, 0 if disabled. */
259c2674 216 uint64_t rotate_size;
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217 /*
218 * Keep a state if this session was rotated after the last stop command.
219 * We only allow one rotation after a stop. At destroy, we also need to
a9577b76 220 * know if a rotation occurred since the last stop to rename the current
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221 * chunk.
222 */
223 bool rotated_after_last_stop;
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224 /*
225 * Condition and trigger for size-based rotations.
226 */
227 struct lttng_condition *rotate_condition;
228 struct lttng_trigger *rotate_trigger;
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229 LTTNG_OPTIONAL(uint64_t) last_trace_chunk_id;
230 struct lttng_trace_chunk *current_trace_chunk;
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231};
232
233/* Prototypes */
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234enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
235 struct ltt_session **out_session);
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236void session_lock(struct ltt_session *session);
237void session_lock_list(void);
71e0a100 238int session_trylock_list(void);
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239void session_unlock(struct ltt_session *session);
240void session_unlock_list(void);
6c9cc2ab 241
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242void session_destroy(struct ltt_session *session);
243
244bool session_get(struct ltt_session *session);
245void session_put(struct ltt_session *session);
246
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247enum consumer_dst_type session_get_consumer_destination_type(
248 const struct ltt_session *session);
249const char *session_get_net_consumer_hostname(
250 const struct ltt_session *session);
251void session_get_net_consumer_ports(
252 const struct ltt_session *session,
253 uint16_t *control_port, uint16_t *data_port);
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254struct lttng_trace_archive_location *session_get_trace_archive_location(
255 struct ltt_session *session);
dd73d57b 256
58a1a227 257struct ltt_session *session_find_by_name(const char *name);
23324029 258struct ltt_session *session_find_by_id(uint64_t id);
99d688f2 259
54d01ffb 260struct ltt_session_list *session_get_list(void);
99d688f2 261void session_list_wait_empty(void);
5b74c7b1 262
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263int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
264
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265int session_reset_rotation_state(struct ltt_session *session,
266 enum lttng_rotation_state result);
267
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268enum lttng_error_code session_switch_trace_chunk(struct ltt_session *session,
269 const char *session_base_path_override,
270 const char *chunk_name_override);
271int session_set_trace_chunk(struct ltt_session *session,
272 struct lttng_trace_chunk *current_trace_chunk);
273
5b74c7b1 274#endif /* _LTT_SESSION_H */
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