sessiond: document effect of rotated_after_last_stop on clear
[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>
3e3665b8 26#include <common/dynamic-array.h>
db66e574 27#include <lttng/rotation.h>
5d65beab 28#include <lttng/location.h>
82b69413 29#include <lttng/lttng-error.h>
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30
31#include "snapshot.h"
00187dd4 32#include "trace-kernel.h"
dd73d57b 33#include "consumer.h"
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34
35struct ltt_ust_session;
00187dd4 36
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37typedef void (*ltt_session_destroy_notifier)(const struct ltt_session *session,
38 void *user_data);
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39typedef void (*ltt_session_clear_notifier)(const struct ltt_session *session,
40 void *user_data);
3e3665b8 41
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42/*
43 * Tracing session list
44 *
45 * Statically declared in session.c and can be accessed by using
54d01ffb 46 * session_get_list() function that returns the pointer to the list.
b5541356 47 */
5b74c7b1 48struct ltt_session_list {
b5541356 49 /*
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50 * This lock protects any read/write access to the list and
51 * next_uuid. All public functions in session.c acquire this
52 * lock and release it before returning. If none of those
53 * functions are used, the lock MUST be acquired in order to
54 * iterate or/and do any actions on that list.
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55 */
56 pthread_mutex_t lock;
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57 /*
58 * This condition variable is signaled on every removal from
59 * the session list.
60 */
61 pthread_cond_t removal_cond;
6c9cc2ab 62
b5541356 63 /*
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64 * Session unique ID generator. The session list lock MUST be
65 * upon update and read of this counter.
b5541356 66 */
d022620a 67 uint64_t next_uuid;
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68
69 /* Linked list head */
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70 struct cds_list_head head;
71};
72
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73/*
74 * This data structure contains information needed to identify a tracing
75 * session for both LTTng and UST.
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76 */
77struct ltt_session {
74babd95 78 char name[NAME_MAX];
b178f53e 79 bool has_auto_generated_name;
46ef2188 80 bool name_contains_creation_time;
73184835 81 char hostname[HOST_NAME_MAX]; /* Local hostname. */
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82 /* Path of the last closed chunk. */
83 char last_chunk_path[LTTNG_PATH_MAX];
b178f53e 84 time_t creation_time;
20fe2104 85 struct ltt_kernel_session *kernel_session;
f6a9efaa 86 struct ltt_ust_session *ust_session;
e32d7f27 87 struct urcu_ref ref;
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88 /*
89 * Protect any read/write on this session data structure. This lock must be
90 * acquired *before* using any public functions declared below. Use
54d01ffb 91 * session_lock() and session_unlock() for that.
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92 */
93 pthread_mutex_t lock;
94 struct cds_list_head list;
d022620a 95 uint64_t id; /* session unique identifier */
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96 /* Indicates if the session has been added to the session list and ht.*/
97 bool published;
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98 /* Indicates if a destroy command has been applied to this session. */
99 bool destroyed;
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100 /* UID/GID of the user owning the session */
101 uid_t uid;
102 gid_t gid;
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103 /*
104 * Network session handle. A value of 0 means that there is no remote
105 * session established.
106 */
107 uint64_t net_handle;
108 /*
109 * This consumer is only set when the create_session_uri call is made.
110 * This contains the temporary information for a consumer output. Upon
111 * creation of the UST or kernel session, this consumer, if available, is
112 * copied into those sessions.
113 */
114 struct consumer_output *consumer;
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115 /*
116 * Indicates whether or not the user has specified an output directory
117 * or if it was configured using the default configuration.
118 */
119 bool has_user_specified_directory;
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120 /* Did at least ONE start command has been triggered?. */
121 unsigned int has_been_started:1;
122 /*
123 * Is the session active? Start trace command sets this to 1 and the stop
124 * command reset it to 0.
125 */
126 unsigned int active:1;
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127
128 /* Snapshot representation in a session. */
129 struct snapshot snapshot;
130 /* Indicate if the session has to output the traces or not. */
131 unsigned int output_traces;
27babd3a 132 /*
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133 * This session is in snapshot mode. This means that channels enabled
134 * will be set in overwrite mode by default and must be in mmap
135 * output mode. Note that snapshots can be taken on a session that
136 * is not in "snapshot_mode". This parameter only affects channel
137 * creation defaults.
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138 */
139 unsigned int snapshot_mode;
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140 /*
141 * A session that has channels that don't use 'mmap' output can't be
142 * used to capture snapshots. This is set to true whenever a
143 * 'splice' kernel channel is enabled.
144 */
145 bool has_non_mmap_channel;
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146 /*
147 * Timer set when the session is created for live reading.
148 */
d98ad589 149 unsigned int live_timer;
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150 /*
151 * Path where to keep the shared memory files.
152 */
153 char shm_path[PATH_MAX];
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154 /*
155 * Node in ltt_sessions_ht_by_id.
156 */
157 struct lttng_ht_node_u64 node;
d88744a4 158 /*
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159 * Timer to check periodically if a relay and/or consumer has completed
160 * the last rotation.
d88744a4 161 */
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162 bool rotation_pending_check_timer_enabled;
163 timer_t rotation_pending_check_timer;
259c2674 164 /* Timer to periodically rotate a session. */
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165 bool rotation_schedule_timer_enabled;
166 timer_t rotation_schedule_timer;
66ea93b1 167 /* Value for periodic rotations, 0 if disabled. */
259c2674 168 uint64_t rotate_timer_period;
66ea93b1 169 /* Value for size-based rotations, 0 if disabled. */
259c2674 170 uint64_t rotate_size;
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171 /*
172 * Keep a state if this session was rotated after the last stop command.
173 * We only allow one rotation after a stop. At destroy, we also need to
a9577b76 174 * know if a rotation occurred since the last stop to rename the current
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175 * chunk. After a stop followed by rotate, all subsequent clear
176 * (without prior start) will succeed, but will be effect-less.
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177 */
178 bool rotated_after_last_stop;
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179 /*
180 * Track whether the session was cleared after last stop. All subsequent
181 * clear (without prior start) will succeed, but will be effect-less. A
182 * subsequent rotate (without prior start) will return an error.
183 */
184 bool cleared_after_last_stop;
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185 /*
186 * True if the session has had an explicit non-quiet rotation.
187 */
188 bool rotated;
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189 /*
190 * Condition and trigger for size-based rotations.
191 */
192 struct lttng_condition *rotate_condition;
193 struct lttng_trigger *rotate_trigger;
d2956687 194 LTTNG_OPTIONAL(uint64_t) most_recent_chunk_id;
82b69413 195 struct lttng_trace_chunk *current_trace_chunk;
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196 struct lttng_trace_chunk *chunk_being_archived;
197 /* Current state of a rotation. */
198 enum lttng_rotation_state rotation_state;
7fdbed1c 199 bool quiet_rotation;
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200 char *last_archived_chunk_name;
201 LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id;
3e3665b8 202 struct lttng_dynamic_array destroy_notifiers;
ccbdaca4 203 struct lttng_dynamic_array clear_notifiers;
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204 /* Session base path override. Set non-null. */
205 char *base_path;
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206};
207
208/* Prototypes */
b178f53e 209enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
e3876bf0 210 struct ltt_session **out_session);
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211void session_lock(struct ltt_session *session);
212void session_lock_list(void);
71e0a100 213int session_trylock_list(void);
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214void session_unlock(struct ltt_session *session);
215void session_unlock_list(void);
6c9cc2ab 216
e32d7f27 217void session_destroy(struct ltt_session *session);
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218int session_add_destroy_notifier(struct ltt_session *session,
219 ltt_session_destroy_notifier notifier, void *user_data);
e32d7f27 220
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221int session_add_clear_notifier(struct ltt_session *session,
222 ltt_session_clear_notifier notifier, void *user_data);
223void session_notify_clear(struct ltt_session *session);
224
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225bool session_get(struct ltt_session *session);
226void session_put(struct ltt_session *session);
227
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228enum consumer_dst_type session_get_consumer_destination_type(
229 const struct ltt_session *session);
230const char *session_get_net_consumer_hostname(
231 const struct ltt_session *session);
232void session_get_net_consumer_ports(
233 const struct ltt_session *session,
234 uint16_t *control_port, uint16_t *data_port);
5d65beab 235struct lttng_trace_archive_location *session_get_trace_archive_location(
3e3665b8 236 const struct ltt_session *session);
dd73d57b 237
58a1a227 238struct ltt_session *session_find_by_name(const char *name);
23324029 239struct ltt_session *session_find_by_id(uint64_t id);
99d688f2 240
54d01ffb 241struct ltt_session_list *session_get_list(void);
99d688f2 242void session_list_wait_empty(void);
5b74c7b1 243
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244int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
245
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246int session_reset_rotation_state(struct ltt_session *session,
247 enum lttng_rotation_state result);
248
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249/* Create a new trace chunk object from the session's configuration. */
250struct lttng_trace_chunk *session_create_new_trace_chunk(
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251 const struct ltt_session *session,
252 const struct consumer_output *consumer_output_override,
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253 const char *session_base_path_override,
254 const char *chunk_name_override);
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255
256/*
257 * Set `new_trace_chunk` as the session's current trace chunk. A reference
258 * to `new_trace_chunk` is acquired by the session. The chunk is created
259 * on remote peers (consumer and relay daemons).
260 *
261 * A reference to the session's current trace chunk is returned through
262 * `current_session_trace_chunk` on success.
263 */
82b69413 264int session_set_trace_chunk(struct ltt_session *session,
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265 struct lttng_trace_chunk *new_trace_chunk,
266 struct lttng_trace_chunk **current_session_trace_chunk);
267
268/*
269 * Close a chunk on the remote peers of a session. Has no effect on the
270 * ltt_session itself.
271 */
343defc2 272int session_close_trace_chunk(struct ltt_session *session,
bbc4768c 273 struct lttng_trace_chunk *trace_chunk,
343defc2 274 enum lttng_trace_chunk_command_type close_command,
ecd1a12f 275 char *path);
82b69413 276
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277bool session_output_supports_trace_chunks(const struct ltt_session *session);
278
5b74c7b1 279#endif /* _LTT_SESSION_H */
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