| 1 | /* |
| 2 | * Copyright (C) 2011 EfficiOS Inc. |
| 3 | * |
| 4 | * SPDX-License-Identifier: GPL-2.0-only |
| 5 | * |
| 6 | */ |
| 7 | |
| 8 | #ifndef _LTT_SESSION_H |
| 9 | #define _LTT_SESSION_H |
| 10 | |
| 11 | #include <limits.h> |
| 12 | #include <stdbool.h> |
| 13 | #include <urcu/list.h> |
| 14 | |
| 15 | #include <common/hashtable/hashtable.hpp> |
| 16 | #include <common/dynamic-array.hpp> |
| 17 | #include <common/make-unique-wrapper.hpp> |
| 18 | #include <common/pthread-lock.hpp> |
| 19 | #include <lttng/rotation.h> |
| 20 | #include <lttng/location.h> |
| 21 | #include <lttng/lttng-error.h> |
| 22 | |
| 23 | #include "snapshot.hpp" |
| 24 | #include "trace-kernel.hpp" |
| 25 | #include "consumer.hpp" |
| 26 | |
| 27 | #define ASSERT_SESSION_LIST_LOCKED() LTTNG_ASSERT(session_trylock_list()) |
| 28 | |
| 29 | struct ltt_ust_session; |
| 30 | |
| 31 | using ltt_session_destroy_notifier = void (*)(const struct ltt_session *, void *); |
| 32 | using ltt_session_clear_notifier = void (*)(const struct ltt_session *, void *); |
| 33 | |
| 34 | namespace lttng { |
| 35 | namespace sessiond { |
| 36 | namespace details { |
| 37 | void locked_session_release(ltt_session *session); |
| 38 | } /* namespace details */ |
| 39 | } /* namespace sessiond */ |
| 40 | } /* namespace lttng */ |
| 41 | |
| 42 | /* |
| 43 | * Tracing session list |
| 44 | * |
| 45 | * Statically declared in session.c and can be accessed by using |
| 46 | * session_get_list() function that returns the pointer to the list. |
| 47 | */ |
| 48 | struct ltt_session_list { |
| 49 | /* |
| 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. |
| 55 | */ |
| 56 | pthread_mutex_t lock; |
| 57 | /* |
| 58 | * This condition variable is signaled on every removal from |
| 59 | * the session list. |
| 60 | */ |
| 61 | pthread_cond_t removal_cond; |
| 62 | |
| 63 | /* |
| 64 | * Session unique ID generator. The session list lock MUST be |
| 65 | * upon update and read of this counter. |
| 66 | */ |
| 67 | uint64_t next_uuid; |
| 68 | |
| 69 | /* Linked list head */ |
| 70 | struct cds_list_head head; |
| 71 | }; |
| 72 | |
| 73 | /* |
| 74 | * This data structure contains information needed to identify a tracing |
| 75 | * session for both LTTng and UST. |
| 76 | */ |
| 77 | struct ltt_session { |
| 78 | using id_t = uint64_t; |
| 79 | using locked_ptr = std::unique_ptr<ltt_session, |
| 80 | lttng::details::create_unique_class<ltt_session, |
| 81 | lttng::sessiond::details::locked_session_release>::deleter>; |
| 82 | using sptr = std::shared_ptr<ltt_session>; |
| 83 | |
| 84 | char name[NAME_MAX]; |
| 85 | bool has_auto_generated_name; |
| 86 | bool name_contains_creation_time; |
| 87 | char hostname[LTTNG_HOST_NAME_MAX]; /* Local hostname. */ |
| 88 | /* Path of the last closed chunk. */ |
| 89 | char last_chunk_path[LTTNG_PATH_MAX]; |
| 90 | time_t creation_time; |
| 91 | struct ltt_kernel_session *kernel_session; |
| 92 | struct ltt_ust_session *ust_session; |
| 93 | struct urcu_ref ref; |
| 94 | /* |
| 95 | * Protect any read/write on this session data structure. This lock must be |
| 96 | * acquired *before* using any public functions declared below. Use |
| 97 | * session_lock() and session_unlock() for that. |
| 98 | */ |
| 99 | pthread_mutex_t lock; |
| 100 | struct cds_list_head list; |
| 101 | /* session unique identifier */ |
| 102 | id_t id; |
| 103 | /* Indicates if the session has been added to the session list and ht.*/ |
| 104 | bool published; |
| 105 | /* Indicates if a destroy command has been applied to this session. */ |
| 106 | bool destroyed; |
| 107 | /* UID/GID of the user owning the session */ |
| 108 | uid_t uid; |
| 109 | gid_t gid; |
| 110 | /* |
| 111 | * Network session handle. A value of 0 means that there is no remote |
| 112 | * session established. |
| 113 | */ |
| 114 | uint64_t net_handle; |
| 115 | /* |
| 116 | * This consumer is only set when the create_session_uri call is made. |
| 117 | * This contains the temporary information for a consumer output. Upon |
| 118 | * creation of the UST or kernel session, this consumer, if available, is |
| 119 | * copied into those sessions. |
| 120 | */ |
| 121 | struct consumer_output *consumer; |
| 122 | /* |
| 123 | * Indicates whether or not the user has specified an output directory |
| 124 | * or if it was configured using the default configuration. |
| 125 | */ |
| 126 | bool has_user_specified_directory; |
| 127 | /* Did at least ONE start command has been triggered?. */ |
| 128 | unsigned int has_been_started:1; |
| 129 | /* |
| 130 | * Is the session active? Start trace command sets this to 1 and the stop |
| 131 | * command reset it to 0. |
| 132 | */ |
| 133 | unsigned int active:1; |
| 134 | |
| 135 | /* Snapshot representation in a session. */ |
| 136 | struct snapshot snapshot; |
| 137 | /* Indicate if the session has to output the traces or not. */ |
| 138 | unsigned int output_traces; |
| 139 | /* |
| 140 | * This session is in snapshot mode. This means that channels enabled |
| 141 | * will be set in overwrite mode by default and must be in mmap |
| 142 | * output mode. Note that snapshots can be taken on a session that |
| 143 | * is not in "snapshot_mode". This parameter only affects channel |
| 144 | * creation defaults. |
| 145 | */ |
| 146 | unsigned int snapshot_mode; |
| 147 | /* |
| 148 | * A session that has channels that don't use 'mmap' output can't be |
| 149 | * used to capture snapshots. This is set to true whenever a |
| 150 | * 'splice' kernel channel is enabled. |
| 151 | */ |
| 152 | bool has_non_mmap_channel; |
| 153 | /* |
| 154 | * Timer set when the session is created for live reading. |
| 155 | */ |
| 156 | unsigned int live_timer; |
| 157 | /* |
| 158 | * Path where to keep the shared memory files. |
| 159 | */ |
| 160 | char shm_path[PATH_MAX]; |
| 161 | /* |
| 162 | * Node in ltt_sessions_ht_by_id. |
| 163 | */ |
| 164 | struct lttng_ht_node_u64 node; |
| 165 | /* |
| 166 | * Node in ltt_sessions_ht_by_name. |
| 167 | */ |
| 168 | struct lttng_ht_node_str node_by_name; |
| 169 | /* |
| 170 | * Timer to check periodically if a relay and/or consumer has completed |
| 171 | * the last rotation. |
| 172 | */ |
| 173 | bool rotation_pending_check_timer_enabled; |
| 174 | timer_t rotation_pending_check_timer; |
| 175 | /* Timer to periodically rotate a session. */ |
| 176 | bool rotation_schedule_timer_enabled; |
| 177 | timer_t rotation_schedule_timer; |
| 178 | /* Value for periodic rotations, 0 if disabled. */ |
| 179 | uint64_t rotate_timer_period; |
| 180 | /* Value for size-based rotations, 0 if disabled. */ |
| 181 | uint64_t rotate_size; |
| 182 | /* |
| 183 | * Keep a state if this session was rotated after the last stop command. |
| 184 | * We only allow one rotation after a stop. At destroy, we also need to |
| 185 | * know if a rotation occurred since the last stop to rename the current |
| 186 | * chunk. After a stop followed by rotate, all subsequent clear |
| 187 | * (without prior start) will succeed, but will be effect-less. |
| 188 | */ |
| 189 | bool rotated_after_last_stop; |
| 190 | /* |
| 191 | * Track whether the session was cleared after last stop. All subsequent |
| 192 | * clear (without prior start) will succeed, but will be effect-less. A |
| 193 | * subsequent rotate (without prior start) will return an error. |
| 194 | */ |
| 195 | bool cleared_after_last_stop; |
| 196 | /* |
| 197 | * True if the session has had an explicit non-quiet rotation. |
| 198 | */ |
| 199 | bool rotated; |
| 200 | /* |
| 201 | * Trigger for size-based rotations. |
| 202 | */ |
| 203 | struct lttng_trigger *rotate_trigger; |
| 204 | LTTNG_OPTIONAL(uint64_t) most_recent_chunk_id; |
| 205 | struct lttng_trace_chunk *current_trace_chunk; |
| 206 | struct lttng_trace_chunk *chunk_being_archived; |
| 207 | /* Current state of a rotation. */ |
| 208 | enum lttng_rotation_state rotation_state; |
| 209 | bool quiet_rotation; |
| 210 | char *last_archived_chunk_name; |
| 211 | LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id; |
| 212 | struct lttng_dynamic_array destroy_notifiers; |
| 213 | struct lttng_dynamic_array clear_notifiers; |
| 214 | /* Session base path override. Set non-null. */ |
| 215 | char *base_path; |
| 216 | }; |
| 217 | |
| 218 | enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid, |
| 219 | struct ltt_session **out_session); |
| 220 | void session_lock(struct ltt_session *session); |
| 221 | void session_unlock(struct ltt_session *session); |
| 222 | |
| 223 | /* |
| 224 | * The session list lock covers more ground than its name implies. While |
| 225 | * it does protect against concurent mutations of the session list, it is |
| 226 | * also used as a multi-session lock when synchronizing newly-registered |
| 227 | * 'user space tracer' and 'agent' applications. |
| 228 | * |
| 229 | * In other words, it prevents tracer configurations from changing while they |
| 230 | * are being transmitted to the various applications. |
| 231 | */ |
| 232 | void session_lock_list(); |
| 233 | int session_trylock_list(); |
| 234 | void session_unlock_list(); |
| 235 | |
| 236 | void session_destroy(struct ltt_session *session); |
| 237 | int session_add_destroy_notifier(struct ltt_session *session, |
| 238 | ltt_session_destroy_notifier notifier, void *user_data); |
| 239 | |
| 240 | int session_add_clear_notifier(struct ltt_session *session, |
| 241 | ltt_session_clear_notifier notifier, void *user_data); |
| 242 | void session_notify_clear(struct ltt_session *session); |
| 243 | |
| 244 | bool session_get(struct ltt_session *session); |
| 245 | void session_put(struct ltt_session *session); |
| 246 | |
| 247 | enum consumer_dst_type session_get_consumer_destination_type( |
| 248 | const struct ltt_session *session); |
| 249 | const char *session_get_net_consumer_hostname( |
| 250 | const struct ltt_session *session); |
| 251 | void session_get_net_consumer_ports( |
| 252 | const struct ltt_session *session, |
| 253 | uint16_t *control_port, uint16_t *data_port); |
| 254 | struct lttng_trace_archive_location *session_get_trace_archive_location( |
| 255 | const struct ltt_session *session); |
| 256 | |
| 257 | struct ltt_session *session_find_by_name(const char *name); |
| 258 | struct ltt_session *session_find_by_id(ltt_session::id_t id); |
| 259 | |
| 260 | struct ltt_session_list *session_get_list(); |
| 261 | void session_list_wait_empty(); |
| 262 | |
| 263 | bool session_access_ok(struct ltt_session *session, uid_t uid); |
| 264 | |
| 265 | int session_reset_rotation_state(struct ltt_session *session, |
| 266 | enum lttng_rotation_state result); |
| 267 | |
| 268 | /* Create a new trace chunk object from the session's configuration. */ |
| 269 | struct lttng_trace_chunk *session_create_new_trace_chunk( |
| 270 | const struct ltt_session *session, |
| 271 | const struct consumer_output *consumer_output_override, |
| 272 | const char *session_base_path_override, |
| 273 | const char *chunk_name_override); |
| 274 | |
| 275 | /* |
| 276 | * Set `new_trace_chunk` as the session's current trace chunk. A reference |
| 277 | * to `new_trace_chunk` is acquired by the session. The chunk is created |
| 278 | * on remote peers (consumer and relay daemons). |
| 279 | * |
| 280 | * A reference to the session's current trace chunk is returned through |
| 281 | * `current_session_trace_chunk` on success. |
| 282 | */ |
| 283 | int session_set_trace_chunk(struct ltt_session *session, |
| 284 | struct lttng_trace_chunk *new_trace_chunk, |
| 285 | struct lttng_trace_chunk **current_session_trace_chunk); |
| 286 | |
| 287 | /* |
| 288 | * Close a chunk on the remote peers of a session. Has no effect on the |
| 289 | * ltt_session itself. |
| 290 | */ |
| 291 | int session_close_trace_chunk(struct ltt_session *session, |
| 292 | struct lttng_trace_chunk *trace_chunk, |
| 293 | enum lttng_trace_chunk_command_type close_command, |
| 294 | char *path); |
| 295 | |
| 296 | /* Open a packet in all channels of a given session. */ |
| 297 | enum lttng_error_code session_open_packets(struct ltt_session *session); |
| 298 | |
| 299 | bool session_output_supports_trace_chunks(const struct ltt_session *session); |
| 300 | |
| 301 | /* |
| 302 | * Sample the id of a session looked up via its name. |
| 303 | * Here the term "sampling" hint the caller that this return the id at a given |
| 304 | * point in time with no guarantee that the session for which the id was |
| 305 | * sampled still exist at that point. |
| 306 | * |
| 307 | * Return 0 when the session is not found, |
| 308 | * Return 1 when the session is found and set `id`. |
| 309 | */ |
| 310 | bool sample_session_id_by_name(const char *name, uint64_t *id); |
| 311 | |
| 312 | namespace lttng { |
| 313 | namespace sessiond { |
| 314 | |
| 315 | /* |
| 316 | * Session list lock must be acquired by the caller. |
| 317 | * The caller must not keep the ownership of the returned locked session |
| 318 | * for longer than strictly necessary. If your intention is to acquire |
| 319 | * a reference to an ltt_session, see `find_session_by_id()`. |
| 320 | */ |
| 321 | ltt_session::locked_ptr find_locked_session_by_id(ltt_session::id_t id); |
| 322 | |
| 323 | /* |
| 324 | * Session list lock must be acquired by the caller. |
| 325 | * The caller must not keep the ownership of the returned locked session |
| 326 | * for longer than strictly necessary. If your intention is to acquire |
| 327 | * a reference to an ltt_session, see `find_session_by_id()`. |
| 328 | */ |
| 329 | ltt_session::sptr find_session_by_id(ltt_session::id_t id); |
| 330 | |
| 331 | } /* namespace sessiond */ |
| 332 | } /* namespace lttng */ |
| 333 | |
| 334 | #endif /* _LTT_SESSION_H */ |