2 * Copyright (C) 2011 EfficiOS Inc.
4 * SPDX-License-Identifier: GPL-2.0-only
13 #include <urcu/list.h>
15 #include <common/hashtable/hashtable.hpp>
16 #include <common/dynamic-array.hpp>
17 #include <lttng/rotation.h>
18 #include <lttng/location.h>
19 #include <lttng/lttng-error.h>
21 #include "snapshot.hpp"
22 #include "trace-kernel.hpp"
23 #include "consumer.hpp"
25 struct ltt_ust_session;
27 typedef void (*ltt_session_destroy_notifier)(const struct ltt_session *session,
29 typedef void (*ltt_session_clear_notifier)(const struct ltt_session *session,
33 * Tracing session list
35 * Statically declared in session.c and can be accessed by using
36 * session_get_list() function that returns the pointer to the list.
38 struct ltt_session_list {
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.
48 * This condition variable is signaled on every removal from
51 pthread_cond_t removal_cond;
54 * Session unique ID generator. The session list lock MUST be
55 * upon update and read of this counter.
59 /* Linked list head */
60 struct cds_list_head head;
64 * This data structure contains information needed to identify a tracing
65 * session for both LTTng and UST.
69 bool has_auto_generated_name;
70 bool name_contains_creation_time;
71 char hostname[LTTNG_HOST_NAME_MAX]; /* Local hostname. */
72 /* Path of the last closed chunk. */
73 char last_chunk_path[LTTNG_PATH_MAX];
75 struct ltt_kernel_session *kernel_session;
76 struct ltt_ust_session *ust_session;
79 * Protect any read/write on this session data structure. This lock must be
80 * acquired *before* using any public functions declared below. Use
81 * session_lock() and session_unlock() for that.
84 struct cds_list_head list;
85 uint64_t id; /* session unique identifier */
86 /* Indicates if the session has been added to the session list and ht.*/
88 /* Indicates if a destroy command has been applied to this session. */
90 /* UID/GID of the user owning the session */
94 * Network session handle. A value of 0 means that there is no remote
95 * session established.
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.
104 struct consumer_output *consumer;
106 * Indicates whether or not the user has specified an output directory
107 * or if it was configured using the default configuration.
109 bool has_user_specified_directory;
110 /* Did at least ONE start command has been triggered?. */
111 unsigned int has_been_started:1;
113 * Is the session active? Start trace command sets this to 1 and the stop
114 * command reset it to 0.
116 unsigned int active:1;
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;
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
129 unsigned int snapshot_mode;
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.
135 bool has_non_mmap_channel;
137 * Timer set when the session is created for live reading.
139 unsigned int live_timer;
141 * Path where to keep the shared memory files.
143 char shm_path[PATH_MAX];
145 * Node in ltt_sessions_ht_by_id.
147 struct lttng_ht_node_u64 node;
149 * Node in ltt_sessions_ht_by_name.
151 struct lttng_ht_node_str node_by_name;
153 * Timer to check periodically if a relay and/or consumer has completed
156 bool rotation_pending_check_timer_enabled;
157 timer_t rotation_pending_check_timer;
158 /* Timer to periodically rotate a session. */
159 bool rotation_schedule_timer_enabled;
160 timer_t rotation_schedule_timer;
161 /* Value for periodic rotations, 0 if disabled. */
162 uint64_t rotate_timer_period;
163 /* Value for size-based rotations, 0 if disabled. */
164 uint64_t rotate_size;
166 * Keep a state if this session was rotated after the last stop command.
167 * We only allow one rotation after a stop. At destroy, we also need to
168 * know if a rotation occurred since the last stop to rename the current
169 * chunk. After a stop followed by rotate, all subsequent clear
170 * (without prior start) will succeed, but will be effect-less.
172 bool rotated_after_last_stop;
174 * Track whether the session was cleared after last stop. All subsequent
175 * clear (without prior start) will succeed, but will be effect-less. A
176 * subsequent rotate (without prior start) will return an error.
178 bool cleared_after_last_stop;
180 * True if the session has had an explicit non-quiet rotation.
184 * Trigger for size-based rotations.
186 struct lttng_trigger *rotate_trigger;
187 LTTNG_OPTIONAL(uint64_t) most_recent_chunk_id;
188 struct lttng_trace_chunk *current_trace_chunk;
189 struct lttng_trace_chunk *chunk_being_archived;
190 /* Current state of a rotation. */
191 enum lttng_rotation_state rotation_state;
193 char *last_archived_chunk_name;
194 LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id;
195 struct lttng_dynamic_array destroy_notifiers;
196 struct lttng_dynamic_array clear_notifiers;
197 /* Session base path override. Set non-null. */
201 enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
202 struct ltt_session **out_session);
203 void session_lock(struct ltt_session *session);
204 void session_unlock(struct ltt_session *session);
207 * The session list lock covers more ground than its name implies. While
208 * it does protect against concurent mutations of the session list, it is
209 * also used as a multi-session lock when synchronizing newly-registered
210 * 'user space tracer' and 'agent' applications.
212 * In other words, it prevents tracer configurations from changing while they
213 * are being transmitted to the various applications.
215 void session_lock_list(void);
216 int session_trylock_list(void);
217 void session_unlock_list(void);
219 void session_destroy(struct ltt_session *session);
220 int session_add_destroy_notifier(struct ltt_session *session,
221 ltt_session_destroy_notifier notifier, void *user_data);
223 int session_add_clear_notifier(struct ltt_session *session,
224 ltt_session_clear_notifier notifier, void *user_data);
225 void session_notify_clear(struct ltt_session *session);
227 bool session_get(struct ltt_session *session);
228 void session_put(struct ltt_session *session);
230 enum consumer_dst_type session_get_consumer_destination_type(
231 const struct ltt_session *session);
232 const char *session_get_net_consumer_hostname(
233 const struct ltt_session *session);
234 void session_get_net_consumer_ports(
235 const struct ltt_session *session,
236 uint16_t *control_port, uint16_t *data_port);
237 struct lttng_trace_archive_location *session_get_trace_archive_location(
238 const struct ltt_session *session);
240 struct ltt_session *session_find_by_name(const char *name);
241 struct ltt_session *session_find_by_id(uint64_t id);
243 struct ltt_session_list *session_get_list(void);
244 void session_list_wait_empty(void);
246 bool session_access_ok(struct ltt_session *session, uid_t uid);
248 int session_reset_rotation_state(struct ltt_session *session,
249 enum lttng_rotation_state result);
251 /* Create a new trace chunk object from the session's configuration. */
252 struct lttng_trace_chunk *session_create_new_trace_chunk(
253 const struct ltt_session *session,
254 const struct consumer_output *consumer_output_override,
255 const char *session_base_path_override,
256 const char *chunk_name_override);
259 * Set `new_trace_chunk` as the session's current trace chunk. A reference
260 * to `new_trace_chunk` is acquired by the session. The chunk is created
261 * on remote peers (consumer and relay daemons).
263 * A reference to the session's current trace chunk is returned through
264 * `current_session_trace_chunk` on success.
266 int session_set_trace_chunk(struct ltt_session *session,
267 struct lttng_trace_chunk *new_trace_chunk,
268 struct lttng_trace_chunk **current_session_trace_chunk);
271 * Close a chunk on the remote peers of a session. Has no effect on the
272 * ltt_session itself.
274 int session_close_trace_chunk(struct ltt_session *session,
275 struct lttng_trace_chunk *trace_chunk,
276 enum lttng_trace_chunk_command_type close_command,
279 /* Open a packet in all channels of a given session. */
280 enum lttng_error_code session_open_packets(struct ltt_session *session);
282 bool session_output_supports_trace_chunks(const struct ltt_session *session);
285 * Sample the id of a session looked up via its name.
286 * Here the term "sampling" hint the caller that this return the id at a given
287 * point in time with no guarantee that the session for which the id was
288 * sampled still exist at that point.
290 * Return 0 when the session is not found,
291 * Return 1 when the session is found and set `id`.
293 bool sample_session_id_by_name(const char *name, uint64_t *id);
295 #endif /* _LTT_SESSION_H */