src/bin/lttng-sessiond/ust-app.h

   1 /*
   2  * Copyright (C) 2011 EfficiOS Inc.
   3  * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * SPDX-License-Identifier: GPL-2.0-only
   6  *
   7  */
   8
   9 #ifndef _LTT_UST_APP_H
  10 #define _LTT_UST_APP_H
  11
  12 #include <stdint.h>
  13 #include <urcu/ref.h>
  14
  15 #include <common/index-allocator.h>
  16 #include <common/uuid.h>
  17
  18 #include "trace-ust.h"
  19 #include "ust-registry.h"
  20 #include "session.h"
  21
  22 #define UST_APP_EVENT_LIST_SIZE 32
  23
  24 /* Process name (short). */
  25 #define UST_APP_PROCNAME_LEN    16
  26
  27 struct lttng_bytecode;
  28 struct lttng_ust_filter_bytecode;
  29
  30 extern int the_ust_consumerd64_fd, the_ust_consumerd32_fd;
  31
  32 /*
  33  * Object used to close the notify socket in a call_rcu(). Since the
  34  * application might not be found, we need an independant object containing the
  35  * notify socket fd.
  36  */
  37 struct ust_app_notify_sock_obj {
  38         int fd;
  39         struct rcu_head head;
  40 };
  41
  42 struct ust_app_ht_key {
  43         const char *name;
  44         const struct lttng_bytecode *filter;
  45         enum lttng_ust_abi_loglevel_type loglevel_type;
  46         int loglevel_value;
  47         const struct lttng_event_exclusion *exclusion;
  48 };
  49
  50 /*
  51  * Application registration data structure.
  52  */
  53 struct ust_register_msg {
  54         enum lttng_ust_ctl_socket_type type;
  55         uint32_t major;
  56         uint32_t minor;
  57         uint32_t abi_major;
  58         uint32_t abi_minor;
  59         pid_t pid;
  60         pid_t ppid;
  61         uid_t uid;
  62         gid_t gid;
  63         uint32_t bits_per_long;
  64         uint32_t uint8_t_alignment;
  65         uint32_t uint16_t_alignment;
  66         uint32_t uint32_t_alignment;
  67         uint32_t uint64_t_alignment;
  68         uint32_t long_alignment;
  69         int byte_order;         /* BIG_ENDIAN or LITTLE_ENDIAN */
  70         char name[LTTNG_UST_ABI_PROCNAME_LEN];
  71 };
  72
  73 /*
  74  * Global applications HT used by the session daemon. This table is indexed by
  75  * PID using the pid_n node and pid value of an ust_app.
  76  */
  77 extern struct lttng_ht *ust_app_ht;
  78
  79 /*
  80  * Global applications HT used by the session daemon. This table is indexed by
  81  * socket using the sock_n node and sock value of an ust_app.
  82  *
  83  * The 'sock' in question here is the 'command' socket.
  84  */
  85 extern struct lttng_ht *ust_app_ht_by_sock;
  86
  87 /*
  88  * Global applications HT used by the session daemon. This table is indexed by
  89  * socket using the notify_sock_n node and notify_sock value of an ust_app.
  90  */
  91 extern struct lttng_ht *ust_app_ht_by_notify_sock;
  92
  93 /* Stream list containing ust_app_stream. */
  94 struct ust_app_stream_list {
  95         unsigned int count;
  96         struct cds_list_head head;
  97 };
  98
  99 struct ust_app_ctx {
 100         int handle;
 101         struct lttng_ust_context_attr ctx;
 102         struct lttng_ust_abi_object_data *obj;
 103         struct lttng_ht_node_ulong node;
 104         struct cds_list_head list;
 105 };
 106
 107 struct ust_app_event {
 108         int enabled;
 109         int handle;
 110         struct lttng_ust_abi_object_data *obj;
 111         struct lttng_ust_abi_event attr;
 112         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 113         struct lttng_ht_node_str node;
 114         struct lttng_bytecode *filter;
 115         struct lttng_event_exclusion *exclusion;
 116 };
 117
 118 struct ust_app_event_notifier_rule {
 119         int enabled;
 120         uint64_t error_counter_index;
 121         int handle;
 122         struct lttng_ust_abi_object_data *obj;
 123         /* Holds a strong reference. */
 124         struct lttng_trigger *trigger;
 125         /* Unique ID returned by the tracer to identify this event notifier. */
 126         uint64_t token;
 127         struct lttng_ht_node_u64 node;
 128         /* The trigger object owns the filter. */
 129         const struct lttng_bytecode *filter;
 130         /* Owned by this. */
 131         struct lttng_event_exclusion *exclusion;
 132         /* For delayed reclaim. */
 133         struct rcu_head rcu_head;
 134 };
 135
 136 struct ust_app_stream {
 137         int handle;
 138         char pathname[PATH_MAX];
 139         /* Format is %s_%d respectively channel name and CPU number. */
 140         char name[DEFAULT_STREAM_NAME_LEN];
 141         struct lttng_ust_abi_object_data *obj;
 142         /* Using a list of streams to keep order. */
 143         struct cds_list_head list;
 144 };
 145
 146 struct ust_app_channel {
 147         int enabled;
 148         int handle;
 149         /* Channel and streams were sent to the UST tracer. */
 150         int is_sent;
 151         /*
 152          * Unique key used to identify the channel on the consumer side.
 153          * 0 is a reserved 'invalid' value used to indicate that the consumer
 154          * does not know about this channel (i.e. an error occurred).
 155          */
 156         uint64_t key;
 157         /* Id of the tracing channel set on creation. */
 158         uint64_t tracing_channel_id;
 159         /* Number of stream that this channel is expected to receive. */
 160         unsigned int expected_stream_count;
 161         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 162         struct lttng_ust_abi_object_data *obj;
 163         struct lttng_ust_ctl_consumer_channel_attr attr;
 164         struct ust_app_stream_list streams;
 165         /* Session pointer that owns this object. */
 166         struct ust_app_session *session;
 167         /*
 168          * Contexts are kept in a hash table for fast lookup and in an ordered list
 169          * so we are able to enable them on the tracer side in the same order the
 170          * user added them.
 171          */
 172         struct lttng_ht *ctx;
 173         struct cds_list_head ctx_list;
 174
 175         struct lttng_ht *events;
 176         uint64_t tracefile_size;
 177         uint64_t tracefile_count;
 178         uint64_t monitor_timer_interval;
 179         /*
 180          * Node indexed by channel name in the channels' hash table of a session.
 181          */
 182         struct lttng_ht_node_str node;
 183         /*
 184          * Node indexed by UST channel object descriptor (handle). Stored in the
 185          * ust_objd hash table in the ust_app object.
 186          */
 187         struct lttng_ht_node_ulong ust_objd_node;
 188         /* For delayed reclaim */
 189         struct rcu_head rcu_head;
 190 };
 191
 192 struct ust_app_session {
 193         /*
 194          * Lock protecting this session's ust app interaction. Held
 195          * across command send/recv to/from app. Never nests within the
 196          * session registry lock.
 197          */
 198         pthread_mutex_t lock;
 199
 200         int enabled;
 201         /* started: has the session been in started state at any time ? */
 202         int started;  /* allows detection of start vs restart. */
 203         int handle;   /* used has unique identifier for app session */
 204
 205         bool deleted;   /* Session deleted flag. Check with lock held. */
 206
 207         /*
 208          * Tracing session ID. Multiple ust app session can have the same tracing
 209          * session id making this value NOT unique to the object.
 210          */
 211         uint64_t tracing_id;
 212         uint64_t id;    /* Unique session identifier */
 213         struct lttng_ht *channels; /* Registered channels */
 214         struct lttng_ht_node_u64 node;
 215         /*
 216          * Node indexed by UST session object descriptor (handle). Stored in the
 217          * ust_sessions_objd hash table in the ust_app object.
 218          */
 219         struct lttng_ht_node_ulong ust_objd_node;
 220         /* Starts with 'ust'; no leading slash. */
 221         char path[PATH_MAX];
 222         /* UID/GID of the application owning the session */
 223         struct lttng_credentials real_credentials;
 224         /* Effective UID and GID. Same as the tracing session. */
 225         struct lttng_credentials effective_credentials;
 226         struct cds_list_head teardown_node;
 227         /*
 228          * Once at least *one* session is created onto the application, the
 229          * corresponding consumer is set so we can use it on unregistration.
 230          */
 231         struct consumer_output *consumer;
 232         enum lttng_buffer_type buffer_type;
 233         /* ABI of the session. Same value as the application. */
 234         uint32_t bits_per_long;
 235         /* For delayed reclaim */
 236         struct rcu_head rcu_head;
 237         /* If the channel's streams have to be outputed or not. */
 238         unsigned int output_traces;
 239         unsigned int live_timer_interval;       /* usec */
 240
 241         /* Metadata channel attributes. */
 242         struct lttng_ust_ctl_consumer_channel_attr metadata_attr;
 243
 244         char root_shm_path[PATH_MAX];
 245         char shm_path[PATH_MAX];
 246 };
 247
 248 /*
 249  * Registered traceable applications. Libust registers to the session daemon
 250  * and a linked list is kept of all running traceable app.
 251  */
 252 struct ust_app {
 253         /*
 254          * The lifetime of 'sock' holds a reference to the application; the
 255          * application management thread will release a reference to the
 256          * application if the application dies.
 257          */
 258         struct urcu_ref ref;
 259         int sock;
 260         pthread_mutex_t sock_lock;      /* Protects sock protocol. */
 261
 262         int notify_sock;
 263         pid_t pid;
 264         pid_t ppid;
 265         uid_t uid;           /* User ID that owns the apps */
 266         gid_t gid;           /* Group ID that owns the apps */
 267
 268         /* App ABI */
 269         uint32_t bits_per_long;
 270         uint32_t uint8_t_alignment;
 271         uint32_t uint16_t_alignment;
 272         uint32_t uint32_t_alignment;
 273         uint32_t uint64_t_alignment;
 274         uint32_t long_alignment;
 275         int byte_order;         /* BIG_ENDIAN or LITTLE_ENDIAN */
 276
 277         int compatible; /* If the lttng-ust tracer version does not match the
 278                                            supported version of the session daemon, this flag is
 279                                            set to 0 (NOT compatible) else 1. */
 280         struct lttng_ust_abi_tracer_version version;
 281         uint32_t v_major;    /* Version major number */
 282         uint32_t v_minor;    /* Version minor number */
 283         /* Extra for the NULL byte. */
 284         char name[UST_APP_PROCNAME_LEN + 1];
 285         /* Type of buffer this application uses. */
 286         enum lttng_buffer_type buffer_type;
 287         struct lttng_ht *sessions;
 288         struct lttng_ht_node_ulong pid_n;
 289         struct lttng_ht_node_ulong sock_n;
 290         struct lttng_ht_node_ulong notify_sock_n;
 291         /*
 292          * This is a list of ust app session that, once the app is going into
 293          * teardown mode, in the RCU call, each node in this list is removed and
 294          * deleted.
 295          *
 296          * Element of the list are added when an application unregisters after each
 297          * ht_del of ust_app_session associated to this app. This list is NOT used
 298          * when a session is destroyed.
 299          */
 300         struct cds_list_head teardown_head;
 301         /*
 302          * Hash table containing ust_app_channel indexed by channel objd.
 303          */
 304         struct lttng_ht *ust_objd;
 305         /*
 306          * Hash table containing ust_app_session indexed by objd.
 307          */
 308         struct lttng_ht *ust_sessions_objd;
 309
 310         /*
 311          * If this application is of the agent domain and this is non negative then
 312          * a lookup MUST be done to acquire a read side reference to the
 313          * corresponding agent app object. If the lookup fails, this should be set
 314          * to a negative value indicating that the agent application is gone.
 315          */
 316         int agent_app_sock;
 317         /*
 318          * Time at which the app is registred.
 319          * Used for path creation
 320          */
 321         time_t registration_time;
 322         /*
 323          * Event notifier
 324          */
 325         struct {
 326                 /*
 327                  * Handle to the lttng_ust object representing the event
 328                  * notifier group.
 329                  */
 330                 struct lttng_ust_abi_object_data *object;
 331                 struct lttng_pipe *event_pipe;
 332                 struct lttng_ust_abi_object_data *counter;
 333                 struct lttng_ust_abi_object_data **counter_cpu;
 334                 int nr_counter_cpu;
 335         } event_notifier_group;
 336         /*
 337          * Hashtable indexing the application's event notifier rule's
 338          * (ust_app_event_notifier_rule) by their token's value.
 339          */
 340         struct lttng_ht *token_to_event_notifier_rule_ht;
 341 };
 342
 343 #ifdef HAVE_LIBLTTNG_UST_CTL
 344
 345 int ust_app_register(struct ust_register_msg *msg, int sock);
 346 int ust_app_register_done(struct ust_app *app);
 347 int ust_app_version(struct ust_app *app);
 348 void ust_app_unregister_by_socket(int sock);
 349 int ust_app_start_trace_all(struct ltt_ust_session *usess);
 350 int ust_app_stop_trace_all(struct ltt_ust_session *usess);
 351 int ust_app_destroy_trace_all(struct ltt_ust_session *usess);
 352 int ust_app_list_events(struct lttng_event **events);
 353 int ust_app_list_event_fields(struct lttng_event_field **fields);
 354 int ust_app_create_event_glb(struct ltt_ust_session *usess,
 355                 struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent);
 356 int ust_app_disable_channel_glb(struct ltt_ust_session *usess,
 357                 struct ltt_ust_channel *uchan);
 358 int ust_app_enable_channel_glb(struct ltt_ust_session *usess,
 359                 struct ltt_ust_channel *uchan);
 360 int ust_app_enable_event_glb(struct ltt_ust_session *usess,
 361                 struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent);
 362 int ust_app_disable_event_glb(struct ltt_ust_session *usess,
 363                 struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent);
 364 int ust_app_add_ctx_channel_glb(struct ltt_ust_session *usess,
 365                 struct ltt_ust_channel *uchan, struct ltt_ust_context *uctx);
 366 void ust_app_global_update(struct ltt_ust_session *usess, struct ust_app *app);
 367 void ust_app_global_update_all(struct ltt_ust_session *usess);
 368 void ust_app_global_update_event_notifier_rules(struct ust_app *app);
 369 void ust_app_global_update_all_event_notifier_rules(void);
 370
 371 void ust_app_clean_list(void);
 372 int ust_app_ht_alloc(void);
 373 struct ust_app *ust_app_find_by_pid(pid_t pid);
 374 struct ust_app_stream *ust_app_alloc_stream(void);
 375 int ust_app_recv_registration(int sock, struct ust_register_msg *msg);
 376 int ust_app_recv_notify(int sock);
 377 void ust_app_add(struct ust_app *app);
 378 struct ust_app *ust_app_create(struct ust_register_msg *msg, int sock);
 379 void ust_app_notify_sock_unregister(int sock);
 380 ssize_t ust_app_push_metadata(struct ust_registry_session *registry,
 381                 struct consumer_socket *socket, int send_zero_data);
 382 enum lttng_error_code ust_app_snapshot_record(
 383                 const struct ltt_ust_session *usess,
 384                 const struct consumer_output *output, int wait,
 385                 uint64_t nb_packets_per_stream);
 386 uint64_t ust_app_get_size_one_more_packet_per_stream(
 387                 const struct ltt_ust_session *usess, uint64_t cur_nr_packets);
 388 struct ust_app *ust_app_find_by_sock(int sock);
 389 int ust_app_uid_get_channel_runtime_stats(uint64_t ust_session_id,
 390                 struct cds_list_head *buffer_reg_uid_list,
 391                 struct consumer_output *consumer, uint64_t uchan_id,
 392                 int overwrite, uint64_t *discarded, uint64_t *lost);
 393 int ust_app_pid_get_channel_runtime_stats(struct ltt_ust_session *usess,
 394                 struct ltt_ust_channel *uchan,
 395                 struct consumer_output *consumer,
 396                 int overwrite, uint64_t *discarded, uint64_t *lost);
 397 int ust_app_regenerate_statedump_all(struct ltt_ust_session *usess);
 398 enum lttng_error_code ust_app_rotate_session(struct ltt_session *session);
 399 enum lttng_error_code ust_app_create_channel_subdirectories(
 400                 const struct ltt_ust_session *session);
 401 int ust_app_release_object(struct ust_app *app,
 402                 struct lttng_ust_abi_object_data *data);
 403 enum lttng_error_code ust_app_clear_session(struct ltt_session *session);
 404 enum lttng_error_code ust_app_open_packets(struct ltt_session *session);
 405
 406 int ust_app_setup_event_notifier_group(struct ust_app *app);
 407
 408 static inline
 409 int ust_app_supported(void)
 410 {
 411         return 1;
 412 }
 413
 414 bool ust_app_supports_notifiers(const struct ust_app *app);
 415 bool ust_app_supports_counters(const struct ust_app *app);
 416
 417 bool ust_app_get(struct ust_app *app);
 418 void ust_app_put(struct ust_app *app);
 419
 420 #else /* HAVE_LIBLTTNG_UST_CTL */
 421
 422 static inline
 423 int ust_app_destroy_trace_all(struct ltt_ust_session *usess)
 424 {
 425         return 0;
 426 }
 427 static inline
 428 int ust_app_start_trace(struct ltt_ust_session *usess, struct ust_app *app)
 429 {
 430         return 0;
 431 }
 432 static inline
 433 int ust_app_start_trace_all(struct ltt_ust_session *usess)
 434 {
 435         return 0;
 436 }
 437 static inline
 438 int ust_app_stop_trace_all(struct ltt_ust_session *usess)
 439 {
 440         return 0;
 441 }
 442 static inline
 443 int ust_app_list_events(struct lttng_event **events)
 444 {
 445         return -ENOSYS;
 446 }
 447 static inline
 448 int ust_app_list_event_fields(struct lttng_event_field **fields)
 449 {
 450         return -ENOSYS;
 451 }
 452 static inline
 453 int ust_app_register(struct ust_register_msg *msg, int sock)
 454 {
 455         return -ENOSYS;
 456 }
 457 static inline
 458 int ust_app_register_done(struct ust_app *app)
 459 {
 460         return -ENOSYS;
 461 }
 462 static inline
 463 int ust_app_version(struct ust_app *app)
 464 {
 465         return -ENOSYS;
 466 }
 467 static inline
 468 void ust_app_unregister_by_socket(int sock)
 469 {
 470 }
 471 static inline
 472 void ust_app_lock_list(void)
 473 {
 474 }
 475 static inline
 476 void ust_app_unlock_list(void)
 477 {
 478 }
 479 static inline
 480 void ust_app_clean_list(void)
 481 {
 482 }
 483 static inline
 484 struct ust_app_list *ust_app_get_list(void)
 485 {
 486         return NULL;
 487 }
 488 static inline
 489 struct ust_app *ust_app_get_by_pid(pid_t pid)
 490 {
 491         return NULL;
 492 }
 493 static inline
 494 int ust_app_ht_alloc(void)
 495 {
 496         return 0;
 497 }
 498 static inline
 499 void ust_app_global_update(struct ltt_ust_session *usess, struct ust_app *app)
 500 {}
 501 static inline
 502 void ust_app_global_update_event_notifier_rules(struct ust_app *app)
 503 {}
 504 static inline
 505 void ust_app_global_update_all_event_notifier_rules(void)
 506 {}
 507 static inline
 508 int ust_app_setup_event_notifier_group(struct ust_app *app)
 509 {
 510         return 0;
 511 }
 512 static inline
 513 int ust_app_disable_channel_glb(struct ltt_ust_session *usess,
 514                 struct ltt_ust_channel *uchan)
 515 {
 516         return 0;
 517 }
 518 static inline
 519 int ust_app_enable_channel_glb(struct ltt_ust_session *usess,
 520                 struct ltt_ust_channel *uchan)
 521 {
 522         return 0;
 523 }
 524 static inline
 525 int ust_app_create_event_glb(struct ltt_ust_session *usess,
 526                 struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent)
 527 {
 528         return 0;
 529 }
 530 static inline
 531 int ust_app_disable_event_glb(struct ltt_ust_session *usess,
 532                 struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent)
 533 {
 534         return 0;
 535 }
 536 static inline
 537 int ust_app_enable_event_glb(struct ltt_ust_session *usess,
 538                 struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent)
 539 {
 540         return 0;
 541 }
 542 static inline
 543 int ust_app_add_ctx_channel_glb(struct ltt_ust_session *usess,
 544                 struct ltt_ust_channel *uchan, struct ltt_ust_context *uctx)
 545 {
 546         return 0;
 547 }
 548 static inline
 549 int ust_app_enable_event_pid(struct ltt_ust_session *usess,
 550                 struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent,
 551                 pid_t pid)
 552 {
 553         return 0;
 554 }
 555 static inline
 556 int ust_app_recv_registration(int sock, struct ust_register_msg *msg)
 557 {
 558         return 0;
 559 }
 560 static inline
 561 int ust_app_recv_notify(int sock)
 562 {
 563         return 0;
 564 }
 565 static inline
 566 struct ust_app *ust_app_create(struct ust_register_msg *msg, int sock)
 567 {
 568         return NULL;
 569 }
 570 static inline
 571 void ust_app_add(struct ust_app *app)
 572 {
 573 }
 574 static inline
 575 void ust_app_notify_sock_unregister(int sock)
 576 {
 577 }
 578 static inline
 579 ssize_t ust_app_push_metadata(struct ust_registry_session *registry,
 580                 struct consumer_socket *socket, int send_zero_data)
 581 {
 582         return 0;
 583 }
 584 static inline
 585 enum lttng_error_code ust_app_snapshot_record(struct ltt_ust_session *usess,
 586                 const struct consumer_output *output, int wait, uint64_t max_stream_size)
 587 {
 588         return 0;
 589 }
 590 static inline
 591 unsigned int ust_app_get_nb_stream(struct ltt_ust_session *usess)
 592 {
 593         return 0;
 594 }
 595 static inline
 596 void ust_app_update_event_notifier_error_count(
 597                 struct lttng_trigger *lttng_trigger)
 598 {
 599         return;
 600 }
 601 static inline
 602 int ust_app_supported(void)
 603 {
 604         return 0;
 605 }
 606 static inline
 607 bool ust_app_supports_notifiers(const struct ust_app *app)
 608 {
 609         return false;
 610 }
 611 static inline
 612 bool ust_app_supports_counters(const struct ust_app *app)
 613 {
 614         return false;
 615 }
 616 static inline
 617 struct ust_app *ust_app_find_by_sock(int sock)
 618 {
 619         return NULL;
 620 }
 621 static inline
 622 struct ust_app *ust_app_find_by_pid(pid_t pid)
 623 {
 624         return NULL;
 625 }
 626 static inline
 627 uint64_t ust_app_get_size_one_more_packet_per_stream(
 628                 const struct ltt_ust_session *usess, uint64_t cur_nr_packets) {
 629         return 0;
 630 }
 631 static inline
 632 int ust_app_uid_get_channel_runtime_stats(uint64_t ust_session_id,
 633                 struct cds_list_head *buffer_reg_uid_list,
 634                 struct consumer_output *consumer, int overwrite,
 635                 uint64_t uchan_id, uint64_t *discarded, uint64_t *lost)
 636 {
 637         return 0;
 638 }
 639
 640 static inline
 641 int ust_app_pid_get_channel_runtime_stats(struct ltt_ust_session *usess,
 642                 struct ltt_ust_channel *uchan,
 643                 struct consumer_output *consumer,
 644                 int overwrite, uint64_t *discarded, uint64_t *lost)
 645 {
 646         return 0;
 647 }
 648
 649 static inline
 650 int ust_app_regenerate_statedump_all(struct ltt_ust_session *usess)
 651 {
 652         return 0;
 653 }
 654
 655 static inline
 656 enum lttng_error_code ust_app_rotate_session(struct ltt_session *session)
 657 {
 658         return 0;
 659 }
 660
 661 static inline
 662 enum lttng_error_code ust_app_create_channel_subdirectories(
 663                 const struct ltt_ust_session *session)
 664 {
 665         return 0;
 666 }
 667
 668 static inline
 669 int ust_app_release_object(struct ust_app *app, struct lttng_ust_abi_object_data *data)
 670 {
 671         return 0;
 672 }
 673
 674 static inline
 675 enum lttng_error_code ust_app_clear_session(struct ltt_session *session)
 676 {
 677         return 0;
 678 }
 679
 680 static inline
 681 enum lttng_error_code ust_app_open_packets(struct ltt_session *session)
 682 {
 683         return 0;
 684 }
 685
 686 static inline
 687 void ust_app_get(struct ust_app *app)
 688 {
 689 }
 690
 691 static inline
 692 void ust_app_put(struct ust_app *app)
 693 {
 694 }
 695
 696 #endif /* HAVE_LIBLTTNG_UST_CTL */
 697
 698 #endif /* _LTT_UST_APP_H */