sessiond: enforce user-exclusive session access in session_access_ok
[lttng-tools.git] / src / bin / lttng-sessiond / session.h
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91d76f53 1/*
ab5be9fa 2 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
5b74c7b1 3 *
ab5be9fa 4 * SPDX-License-Identifier: GPL-2.0-only
5b74c7b1 5 *
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6 */
7
8#ifndef _LTT_SESSION_H
9#define _LTT_SESSION_H
10
73184835 11#include <limits.h>
5c408ad8 12#include <stdbool.h>
20fe2104 13#include <urcu/list.h>
d4a2a84a 14
6dc3064a 15#include <common/hashtable/hashtable.h>
3e3665b8 16#include <common/dynamic-array.h>
db66e574 17#include <lttng/rotation.h>
5d65beab 18#include <lttng/location.h>
82b69413 19#include <lttng/lttng-error.h>
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20
21#include "snapshot.h"
00187dd4 22#include "trace-kernel.h"
dd73d57b 23#include "consumer.h"
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24
25struct ltt_ust_session;
00187dd4 26
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27typedef void (*ltt_session_destroy_notifier)(const struct ltt_session *session,
28 void *user_data);
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29typedef void (*ltt_session_clear_notifier)(const struct ltt_session *session,
30 void *user_data);
3e3665b8 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;
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47 /*
48 * This condition variable is signaled on every removal from
49 * the session list.
50 */
51 pthread_cond_t removal_cond;
6c9cc2ab 52
b5541356 53 /*
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54 * Session unique ID generator. The session list lock MUST be
55 * upon update and read of this counter.
b5541356 56 */
d022620a 57 uint64_t next_uuid;
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58
59 /* Linked list head */
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60 struct cds_list_head head;
61};
62
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63/*
64 * This data structure contains information needed to identify a tracing
65 * session for both LTTng and UST.
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66 */
67struct ltt_session {
74babd95 68 char name[NAME_MAX];
b178f53e 69 bool has_auto_generated_name;
46ef2188 70 bool name_contains_creation_time;
73184835 71 char hostname[HOST_NAME_MAX]; /* Local hostname. */
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72 /* Path of the last closed chunk. */
73 char last_chunk_path[LTTNG_PATH_MAX];
b178f53e 74 time_t creation_time;
20fe2104 75 struct ltt_kernel_session *kernel_session;
f6a9efaa 76 struct ltt_ust_session *ust_session;
e32d7f27 77 struct urcu_ref ref;
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78 /*
79 * Protect any read/write on this session data structure. This lock must be
80 * acquired *before* using any public functions declared below. Use
54d01ffb 81 * session_lock() and session_unlock() for that.
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82 */
83 pthread_mutex_t lock;
84 struct cds_list_head list;
d022620a 85 uint64_t id; /* session unique identifier */
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86 /* Indicates if the session has been added to the session list and ht.*/
87 bool published;
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88 /* Indicates if a destroy command has been applied to this session. */
89 bool destroyed;
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90 /* UID/GID of the user owning the session */
91 uid_t uid;
92 gid_t gid;
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93 /*
94 * Network session handle. A value of 0 means that there is no remote
95 * session established.
96 */
97 uint64_t net_handle;
98 /*
99 * This consumer is only set when the create_session_uri call is made.
100 * This contains the temporary information for a consumer output. Upon
101 * creation of the UST or kernel session, this consumer, if available, is
102 * copied into those sessions.
103 */
104 struct consumer_output *consumer;
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105 /*
106 * Indicates whether or not the user has specified an output directory
107 * or if it was configured using the default configuration.
108 */
109 bool has_user_specified_directory;
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110 /* Did at least ONE start command has been triggered?. */
111 unsigned int has_been_started:1;
112 /*
113 * Is the session active? Start trace command sets this to 1 and the stop
114 * command reset it to 0.
115 */
116 unsigned int active:1;
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117
118 /* Snapshot representation in a session. */
119 struct snapshot snapshot;
120 /* Indicate if the session has to output the traces or not. */
121 unsigned int output_traces;
27babd3a 122 /*
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123 * This session is in snapshot mode. This means that channels enabled
124 * will be set in overwrite mode by default and must be in mmap
125 * output mode. Note that snapshots can be taken on a session that
126 * is not in "snapshot_mode". This parameter only affects channel
127 * creation defaults.
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128 */
129 unsigned int snapshot_mode;
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130 /*
131 * A session that has channels that don't use 'mmap' output can't be
132 * used to capture snapshots. This is set to true whenever a
133 * 'splice' kernel channel is enabled.
134 */
135 bool has_non_mmap_channel;
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136 /*
137 * Timer set when the session is created for live reading.
138 */
d98ad589 139 unsigned int live_timer;
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140 /*
141 * Path where to keep the shared memory files.
142 */
143 char shm_path[PATH_MAX];
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144 /*
145 * Node in ltt_sessions_ht_by_id.
146 */
147 struct lttng_ht_node_u64 node;
d88744a4 148 /*
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149 * Timer to check periodically if a relay and/or consumer has completed
150 * the last rotation.
d88744a4 151 */
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152 bool rotation_pending_check_timer_enabled;
153 timer_t rotation_pending_check_timer;
259c2674 154 /* Timer to periodically rotate a session. */
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155 bool rotation_schedule_timer_enabled;
156 timer_t rotation_schedule_timer;
66ea93b1 157 /* Value for periodic rotations, 0 if disabled. */
259c2674 158 uint64_t rotate_timer_period;
66ea93b1 159 /* Value for size-based rotations, 0 if disabled. */
259c2674 160 uint64_t rotate_size;
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161 /*
162 * Keep a state if this session was rotated after the last stop command.
163 * We only allow one rotation after a stop. At destroy, we also need to
a9577b76 164 * know if a rotation occurred since the last stop to rename the current
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165 * chunk. After a stop followed by rotate, all subsequent clear
166 * (without prior start) will succeed, but will be effect-less.
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167 */
168 bool rotated_after_last_stop;
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169 /*
170 * Track whether the session was cleared after last stop. All subsequent
171 * clear (without prior start) will succeed, but will be effect-less. A
172 * subsequent rotate (without prior start) will return an error.
173 */
174 bool cleared_after_last_stop;
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175 /*
176 * True if the session has had an explicit non-quiet rotation.
177 */
178 bool rotated;
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179 /*
180 * Condition and trigger for size-based rotations.
181 */
182 struct lttng_condition *rotate_condition;
183 struct lttng_trigger *rotate_trigger;
d2956687 184 LTTNG_OPTIONAL(uint64_t) most_recent_chunk_id;
82b69413 185 struct lttng_trace_chunk *current_trace_chunk;
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186 struct lttng_trace_chunk *chunk_being_archived;
187 /* Current state of a rotation. */
188 enum lttng_rotation_state rotation_state;
7fdbed1c 189 bool quiet_rotation;
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190 char *last_archived_chunk_name;
191 LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id;
3e3665b8 192 struct lttng_dynamic_array destroy_notifiers;
ccbdaca4 193 struct lttng_dynamic_array clear_notifiers;
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194 /* Session base path override. Set non-null. */
195 char *base_path;
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196};
197
b178f53e 198enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
e3876bf0 199 struct ltt_session **out_session);
54d01ffb 200void session_lock(struct ltt_session *session);
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201void session_unlock(struct ltt_session *session);
202
203/*
204 * The session list lock covers more ground than its name implies. While
205 * it does protect against concurent mutations of the session list, it is
206 * also used as a multi-session lock when synchronizing newly-registered
207 * 'user space tracer' and 'agent' applications.
208 *
209 * In other words, it prevents session configurations from changing while they
210 * are being transmitted to the various applications.
211 */
54d01ffb 212void session_lock_list(void);
71e0a100 213int session_trylock_list(void);
54d01ffb 214void session_unlock_list(void);
6c9cc2ab 215
e32d7f27 216void session_destroy(struct ltt_session *session);
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217int session_add_destroy_notifier(struct ltt_session *session,
218 ltt_session_destroy_notifier notifier, void *user_data);
e32d7f27 219
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220int session_add_clear_notifier(struct ltt_session *session,
221 ltt_session_clear_notifier notifier, void *user_data);
222void session_notify_clear(struct ltt_session *session);
223
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224bool session_get(struct ltt_session *session);
225void session_put(struct ltt_session *session);
226
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227enum consumer_dst_type session_get_consumer_destination_type(
228 const struct ltt_session *session);
229const char *session_get_net_consumer_hostname(
230 const struct ltt_session *session);
231void session_get_net_consumer_ports(
232 const struct ltt_session *session,
233 uint16_t *control_port, uint16_t *data_port);
5d65beab 234struct lttng_trace_archive_location *session_get_trace_archive_location(
3e3665b8 235 const struct ltt_session *session);
dd73d57b 236
58a1a227 237struct ltt_session *session_find_by_name(const char *name);
23324029 238struct ltt_session *session_find_by_id(uint64_t id);
99d688f2 239
54d01ffb 240struct ltt_session_list *session_get_list(void);
99d688f2 241void session_list_wait_empty(void);
5b74c7b1 242
d7b377ed 243bool session_access_ok(struct ltt_session *session, uid_t uid);
2f77fc4b 244
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245int session_reset_rotation_state(struct ltt_session *session,
246 enum lttng_rotation_state result);
247
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248/* Create a new trace chunk object from the session's configuration. */
249struct lttng_trace_chunk *session_create_new_trace_chunk(
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250 const struct ltt_session *session,
251 const struct consumer_output *consumer_output_override,
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252 const char *session_base_path_override,
253 const char *chunk_name_override);
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254
255/*
256 * Set `new_trace_chunk` as the session's current trace chunk. A reference
257 * to `new_trace_chunk` is acquired by the session. The chunk is created
258 * on remote peers (consumer and relay daemons).
259 *
260 * A reference to the session's current trace chunk is returned through
261 * `current_session_trace_chunk` on success.
262 */
82b69413 263int session_set_trace_chunk(struct ltt_session *session,
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264 struct lttng_trace_chunk *new_trace_chunk,
265 struct lttng_trace_chunk **current_session_trace_chunk);
266
267/*
268 * Close a chunk on the remote peers of a session. Has no effect on the
269 * ltt_session itself.
270 */
343defc2 271int session_close_trace_chunk(struct ltt_session *session,
bbc4768c 272 struct lttng_trace_chunk *trace_chunk,
343defc2 273 enum lttng_trace_chunk_command_type close_command,
ecd1a12f 274 char *path);
82b69413 275
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276/* Open a packet in all channels of a given session. */
277enum lttng_error_code session_open_packets(struct ltt_session *session);
278
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279bool session_output_supports_trace_chunks(const struct ltt_session *session);
280
5b74c7b1 281#endif /* _LTT_SESSION_H */
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