2 * Copyright (C) 2011 EfficiOS Inc.
4 * SPDX-License-Identifier: GPL-2.0-only
11 #include "consumer.hpp"
12 #include "snapshot.hpp"
13 #include "trace-kernel.hpp"
15 #include <common/dynamic-array.hpp>
16 #include <common/hashtable/hashtable.hpp>
17 #include <common/make-unique-wrapper.hpp>
18 #include <common/pthread-lock.hpp>
20 #include <lttng/location.h>
21 #include <lttng/lttng-error.h>
22 #include <lttng/rotation.h>
24 #include <condition_variable>
28 #include <urcu/list.h>
30 #define ASSERT_SESSION_LIST_LOCKED() LTTNG_ASSERT(session_trylock_list())
32 struct ltt_ust_session;
34 using ltt_session_destroy_notifier = void (*)(const struct ltt_session *, void *);
35 using ltt_session_clear_notifier = void (*)(const struct ltt_session *, void *);
40 void locked_session_release(ltt_session *session);
41 } /* namespace details */
42 } /* namespace sessiond */
43 } /* namespace lttng */
46 * Tracing session list
48 * Statically declared in session.c and can be accessed by using
49 * session_get_list() function that returns the pointer to the list.
51 struct ltt_session_list {
53 * This lock protects any read/write access to the list and
54 * next_uuid. All public functions in session.c acquire this
55 * lock and release it before returning. If none of those
56 * functions are used, the lock MUST be acquired in order to
57 * iterate or/and do any actions on that list.
61 * This condition variable is signaled on every removal from
64 std::condition_variable removal_cond;
67 * Session unique ID generator. The session list lock MUST be
68 * upon update and read of this counter.
70 uint64_t next_uuid = 0;
72 /* Linked list head */
73 struct cds_list_head head = CDS_LIST_HEAD_INIT(head);
77 * This data structure contains information needed to identify a tracing
78 * session for both LTTng and UST.
81 using id_t = uint64_t;
83 std::unique_ptr<ltt_session,
84 lttng::memory::create_deleter_class<
86 lttng::sessiond::details::locked_session_release>::deleter>;
87 using sptr = std::shared_ptr<ltt_session>;
90 bool has_auto_generated_name;
91 bool name_contains_creation_time;
92 char hostname[LTTNG_HOST_NAME_MAX]; /* Local hostname. */
93 /* Path of the last closed chunk. */
94 char last_chunk_path[LTTNG_PATH_MAX];
96 struct ltt_kernel_session *kernel_session;
97 struct ltt_ust_session *ust_session;
100 * Protect any read/write on this session data structure. This lock must be
101 * acquired *before* using any public functions declared below. Use
102 * session_lock() and session_unlock() for that.
104 pthread_mutex_t lock;
105 struct cds_list_head list;
106 /* session unique identifier */
108 /* Indicates if the session has been added to the session list and ht.*/
110 /* Indicates if a destroy command has been applied to this session. */
112 /* UID/GID of the user owning the session */
116 * Network session handle. A value of 0 means that there is no remote
117 * session established.
121 * This consumer is only set when the create_session_uri call is made.
122 * This contains the temporary information for a consumer output. Upon
123 * creation of the UST or kernel session, this consumer, if available, is
124 * copied into those sessions.
126 struct consumer_output *consumer;
128 * Indicates whether or not the user has specified an output directory
129 * or if it was configured using the default configuration.
131 bool has_user_specified_directory;
132 /* Did at least ONE start command has been triggered?. */
133 bool has_been_started;
134 /* Is the session active? */
137 /* Snapshot representation in a session. */
138 struct snapshot snapshot;
139 /* Indicate if the session has to output the traces or not. */
140 unsigned int output_traces;
142 * This session is in snapshot mode. This means that channels enabled
143 * will be set in overwrite mode by default and must be in mmap
144 * output mode. Note that snapshots can be taken on a session that
145 * is not in "snapshot_mode". This parameter only affects channel
148 unsigned int snapshot_mode;
150 * A session that has channels that don't use 'mmap' output can't be
151 * used to capture snapshots. This is set to true whenever a
152 * 'splice' kernel channel is enabled.
154 bool has_non_mmap_channel;
156 * Timer set when the session is created for live reading.
158 unsigned int live_timer;
160 * Path where to keep the shared memory files.
162 char shm_path[PATH_MAX];
164 * Node in ltt_sessions_ht_by_id.
166 struct lttng_ht_node_u64 node;
168 * Node in ltt_sessions_ht_by_name.
170 struct lttng_ht_node_str node_by_name;
172 * Timer to check periodically if a relay and/or consumer has completed
175 bool rotation_pending_check_timer_enabled;
176 timer_t rotation_pending_check_timer;
177 /* Timer to periodically rotate a session. */
178 bool rotation_schedule_timer_enabled;
179 timer_t rotation_schedule_timer;
180 /* Value for periodic rotations, 0 if disabled. */
181 uint64_t rotate_timer_period;
182 /* Value for size-based rotations, 0 if disabled. */
183 uint64_t rotate_size;
185 * Keep a state if this session was rotated after the last stop command.
186 * We only allow one rotation after a stop. At destroy, we also need to
187 * know if a rotation occurred since the last stop to rename the current
188 * chunk. After a stop followed by rotate, all subsequent clear
189 * (without prior start) will succeed, but will be effect-less.
191 bool rotated_after_last_stop;
193 * Track whether the session was cleared after last stop. All subsequent
194 * clear (without prior start) will succeed, but will be effect-less. A
195 * subsequent rotate (without prior start) will return an error.
197 bool cleared_after_last_stop;
199 * True if the session has had an explicit non-quiet rotation.
203 * Trigger for size-based rotations.
205 struct lttng_trigger *rotate_trigger;
206 LTTNG_OPTIONAL(uint64_t) most_recent_chunk_id;
207 struct lttng_trace_chunk *current_trace_chunk;
208 struct lttng_trace_chunk *chunk_being_archived;
209 /* Current state of a rotation. */
210 enum lttng_rotation_state rotation_state;
212 char *last_archived_chunk_name;
213 LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id;
214 struct lttng_dynamic_array destroy_notifiers;
215 struct lttng_dynamic_array clear_notifiers;
216 /* Session base path override. Set non-null. */
220 enum lttng_error_code
221 session_create(const char *name, uid_t uid, gid_t gid, struct ltt_session **out_session);
222 void session_lock(struct ltt_session *session);
223 void session_unlock(struct ltt_session *session);
226 * The session list lock covers more ground than its name implies. While
227 * it does protect against concurent mutations of the session list, it is
228 * also used as a multi-session lock when synchronizing newly-registered
229 * 'user space tracer' and 'agent' applications.
231 * In other words, it prevents tracer configurations from changing while they
232 * are being transmitted to the various applications.
234 void session_lock_list() noexcept;
235 int session_trylock_list() noexcept;
236 void session_unlock_list() noexcept;
238 void session_destroy(struct ltt_session *session);
239 int session_add_destroy_notifier(struct ltt_session *session,
240 ltt_session_destroy_notifier notifier,
243 int session_add_clear_notifier(struct ltt_session *session,
244 ltt_session_clear_notifier notifier,
246 void session_notify_clear(ltt_session& session);
248 bool session_get(struct ltt_session *session);
249 void session_put(struct ltt_session *session);
251 enum consumer_dst_type session_get_consumer_destination_type(const struct ltt_session *session);
252 const char *session_get_net_consumer_hostname(const struct ltt_session *session);
253 void session_get_net_consumer_ports(const struct ltt_session *session,
254 uint16_t *control_port,
255 uint16_t *data_port);
256 struct lttng_trace_archive_location *
257 session_get_trace_archive_location(const struct ltt_session *session);
259 struct ltt_session *session_find_by_name(const char *name);
260 struct ltt_session *session_find_by_id(ltt_session::id_t id);
262 struct ltt_session_list *session_get_list();
263 void session_list_wait_empty();
265 bool session_access_ok(struct ltt_session *session, uid_t uid);
267 int session_reset_rotation_state(ltt_session& session, enum lttng_rotation_state result);
269 /* Create a new trace chunk object from the session's configuration. */
270 struct lttng_trace_chunk *
271 session_create_new_trace_chunk(const struct ltt_session *session,
272 const struct consumer_output *consumer_output_override,
273 const char *session_base_path_override,
274 const char *chunk_name_override);
277 * Set `new_trace_chunk` as the session's current trace chunk. A reference
278 * to `new_trace_chunk` is acquired by the session. The chunk is created
279 * on remote peers (consumer and relay daemons).
281 * A reference to the session's current trace chunk is returned through
282 * `current_session_trace_chunk` on success.
284 int session_set_trace_chunk(struct ltt_session *session,
285 struct lttng_trace_chunk *new_trace_chunk,
286 struct lttng_trace_chunk **current_session_trace_chunk);
289 * Close a chunk on the remote peers of a session. Has no effect on the
290 * ltt_session itself.
292 int session_close_trace_chunk(struct ltt_session *session,
293 struct lttng_trace_chunk *trace_chunk,
294 enum lttng_trace_chunk_command_type close_command,
297 /* Open a packet in all channels of a given session. */
298 enum lttng_error_code session_open_packets(struct ltt_session *session);
300 bool session_output_supports_trace_chunks(const struct ltt_session *session);
303 * Sample the id of a session looked up via its name.
304 * Here the term "sampling" hint the caller that this return the id at a given
305 * point in time with no guarantee that the session for which the id was
306 * sampled still exist at that point.
308 * Return 0 when the session is not found,
309 * Return 1 when the session is found and set `id`.
311 bool sample_session_id_by_name(const char *name, uint64_t *id);
317 * Session list lock must be acquired by the caller.
318 * The caller must not keep the ownership of the returned locked session
319 * for longer than strictly necessary. If your intention is to acquire
320 * a reference to an ltt_session, see `find_session_by_id()`.
322 ltt_session::locked_ref find_locked_session_by_id(ltt_session::id_t id);
324 ltt_session::sptr find_session_by_id(ltt_session::id_t id);
326 } /* namespace sessiond */
327 } /* namespace lttng */
329 #endif /* _LTT_SESSION_H */