include/lttng/ust-events.h

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * Holds LTTng per-session event registry.
   7  */
   8
   9 #ifndef _LTTNG_UST_EVENTS_H
  10 #define _LTTNG_UST_EVENTS_H
  11
  12 #include <urcu/list.h>
  13 #include <urcu/hlist.h>
  14 #include <stddef.h>
  15 #include <stdint.h>
  16 #include <lttng/ust-abi.h>
  17 #include <lttng/ust-tracer.h>
  18 #include <lttng/ust-endian.h>
  19 #include <float.h>
  20 #include <errno.h>
  21 #include <urcu/ref.h>
  22 #include <pthread.h>
  23
  24 #ifndef LTTNG_PACKED
  25 #error "LTTNG_PACKED should be defined"
  26 #endif
  27
  28 #ifdef __cplusplus
  29 extern "C" {
  30 #endif
  31
  32 #define LTTNG_UST_UUID_LEN              16
  33
  34 /*
  35  * Tracepoint provider version. Compatibility based on the major number.
  36  * Older tracepoint providers can always register to newer lttng-ust
  37  * library, but the opposite is rejected: a newer tracepoint provider is
  38  * rejected by an older lttng-ust library.
  39  */
  40 #define LTTNG_UST_PROVIDER_MAJOR        2
  41 #define LTTNG_UST_PROVIDER_MINOR        0
  42
  43 struct lttng_channel;
  44 struct lttng_session;
  45 struct lttng_ust_lib_ring_buffer_ctx;
  46 struct lttng_event_field;
  47 struct lttng_event_notifier_group;
  48
  49 /*
  50  * Data structures used by tracepoint event declarations, and by the
  51  * tracer. Those structures have padding for future extension.
  52  */
  53
  54 /* Type description */
  55
  56 /* Update the astract_types name table in lttng-types.c along with this enum */
  57 enum lttng_abstract_types {
  58         atype_integer,
  59         atype_string,
  60         atype_float,
  61         atype_dynamic,
  62         atype_enum_nestable,
  63         atype_array_nestable,
  64         atype_sequence_nestable,
  65         atype_struct_nestable,
  66         NR_ABSTRACT_TYPES,
  67 };
  68
  69 /* Update the string_encodings name table in lttng-types.c along with this enum */
  70 enum lttng_string_encodings {
  71         lttng_encode_none = 0,
  72         lttng_encode_UTF8 = 1,
  73         lttng_encode_ASCII = 2,
  74         NR_STRING_ENCODINGS,
  75 };
  76
  77 struct lttng_enum_value {
  78         unsigned long long value;
  79         unsigned int signedness:1;
  80 };
  81
  82 enum lttng_enum_entry_options {
  83         LTTNG_ENUM_ENTRY_OPTION_IS_AUTO = 1U << 0,
  84 };
  85
  86 #define LTTNG_UST_ENUM_ENTRY_PADDING    16
  87 struct lttng_enum_entry {
  88         struct lttng_enum_value start, end; /* start and end are inclusive */
  89         const char *string;
  90         union {
  91                 struct {
  92                         unsigned int options;
  93                 } LTTNG_PACKED extra;
  94                 char padding[LTTNG_UST_ENUM_ENTRY_PADDING];
  95         } u;
  96 };
  97
  98 #define __type_integer(_type, _byte_order, _base, _encoding)    \
  99         {                                                       \
 100           .atype = atype_integer,                               \
 101           .u =                                                  \
 102                 {                                               \
 103                   .integer =                                    \
 104                         {                                       \
 105                           .size = sizeof(_type) * CHAR_BIT,     \
 106                           .alignment = lttng_alignof(_type) * CHAR_BIT, \
 107                           .signedness = lttng_is_signed_type(_type), \
 108                           .reverse_byte_order = _byte_order != BYTE_ORDER, \
 109                           .base = _base,                        \
 110                           .encoding = lttng_encode_##_encoding, \
 111                         }                                       \
 112                 },                                              \
 113         }                                                       \
 114
 115 #define LTTNG_UST_INTEGER_TYPE_PADDING  24
 116 struct lttng_integer_type {
 117         unsigned int size;              /* in bits */
 118         unsigned short alignment;       /* in bits */
 119         unsigned int signedness:1;
 120         unsigned int reverse_byte_order:1;
 121         unsigned int base;              /* 2, 8, 10, 16, for pretty print */
 122         enum lttng_string_encodings encoding;
 123         char padding[LTTNG_UST_INTEGER_TYPE_PADDING];
 124 };
 125
 126 /*
 127  * Only float and double are supported. long double is not supported at
 128  * the moment.
 129  */
 130 #define _float_mant_dig(_type)                                          \
 131         (sizeof(_type) == sizeof(float) ? FLT_MANT_DIG                  \
 132                 : (sizeof(_type) == sizeof(double) ? DBL_MANT_DIG       \
 133                 : 0))
 134
 135 #define __type_float(_type)                                     \
 136         {                                                       \
 137           .atype = atype_float,                                 \
 138           .u =                                                  \
 139                 {                                               \
 140                   ._float =                                     \
 141                         {                                       \
 142                           .exp_dig = sizeof(_type) * CHAR_BIT   \
 143                                           - _float_mant_dig(_type), \
 144                           .mant_dig = _float_mant_dig(_type),   \
 145                           .alignment = lttng_alignof(_type) * CHAR_BIT, \
 146                           .reverse_byte_order = BYTE_ORDER != FLOAT_WORD_ORDER, \
 147                         }                                       \
 148                 }                                               \
 149         }                                                       \
 150
 151 #define LTTNG_UST_FLOAT_TYPE_PADDING    24
 152 struct lttng_float_type {
 153         unsigned int exp_dig;           /* exponent digits, in bits */
 154         unsigned int mant_dig;          /* mantissa digits, in bits */
 155         unsigned short alignment;       /* in bits */
 156         unsigned int reverse_byte_order:1;
 157         char padding[LTTNG_UST_FLOAT_TYPE_PADDING];
 158 };
 159
 160 #define LTTNG_UST_TYPE_PADDING  128
 161 struct lttng_type {
 162         enum lttng_abstract_types atype;
 163         union {
 164                 /* provider ABI 2.0 */
 165                 struct lttng_integer_type integer;
 166                 struct lttng_float_type _float;
 167                 struct {
 168                         enum lttng_string_encodings encoding;
 169                 } string;
 170                 struct {
 171                         const struct lttng_enum_desc *desc;     /* Enumeration mapping */
 172                         struct lttng_type *container_type;
 173                 } enum_nestable;
 174                 struct {
 175                         const struct lttng_type *elem_type;
 176                         unsigned int length;                    /* Num. elems. */
 177                         unsigned int alignment;
 178                 } array_nestable;
 179                 struct {
 180                         const char *length_name;                /* Length field name. */
 181                         const struct lttng_type *elem_type;
 182                         unsigned int alignment;                 /* Alignment before elements. */
 183                 } sequence_nestable;
 184                 struct {
 185                         unsigned int nr_fields;
 186                         const struct lttng_event_field *fields; /* Array of fields. */
 187                         unsigned int alignment;
 188                 } struct_nestable;
 189
 190                 char padding[LTTNG_UST_TYPE_PADDING];
 191         } u;
 192 };
 193
 194 #define LTTNG_UST_ENUM_TYPE_PADDING     24
 195 struct lttng_enum_desc {
 196         const char *name;
 197         const struct lttng_enum_entry *entries;
 198         unsigned int nr_entries;
 199         char padding[LTTNG_UST_ENUM_TYPE_PADDING];
 200 };
 201
 202 /*
 203  * Event field description
 204  *
 205  * IMPORTANT: this structure is part of the ABI between the probe and
 206  * UST. Fields need to be only added at the end, never reordered, never
 207  * removed.
 208  */
 209
 210 #define LTTNG_UST_EVENT_FIELD_PADDING   28
 211 struct lttng_event_field {
 212         const char *name;
 213         struct lttng_type type;
 214         unsigned int nowrite;   /* do not write into trace */
 215         union {
 216                 struct {
 217                         unsigned int nofilter:1;        /* do not consider for filter */
 218                 } ext;
 219                 char padding[LTTNG_UST_EVENT_FIELD_PADDING];
 220         } u;
 221 };
 222
 223 enum lttng_ust_dynamic_type {
 224         LTTNG_UST_DYNAMIC_TYPE_NONE,
 225         LTTNG_UST_DYNAMIC_TYPE_S8,
 226         LTTNG_UST_DYNAMIC_TYPE_S16,
 227         LTTNG_UST_DYNAMIC_TYPE_S32,
 228         LTTNG_UST_DYNAMIC_TYPE_S64,
 229         LTTNG_UST_DYNAMIC_TYPE_U8,
 230         LTTNG_UST_DYNAMIC_TYPE_U16,
 231         LTTNG_UST_DYNAMIC_TYPE_U32,
 232         LTTNG_UST_DYNAMIC_TYPE_U64,
 233         LTTNG_UST_DYNAMIC_TYPE_FLOAT,
 234         LTTNG_UST_DYNAMIC_TYPE_DOUBLE,
 235         LTTNG_UST_DYNAMIC_TYPE_STRING,
 236         _NR_LTTNG_UST_DYNAMIC_TYPES,
 237 };
 238
 239 struct lttng_ctx_value {
 240         enum lttng_ust_dynamic_type sel;
 241         union {
 242                 int64_t s64;
 243                 uint64_t u64;
 244                 const char *str;
 245                 double d;
 246         } u;
 247 };
 248
 249 struct lttng_perf_counter_field;
 250
 251 #define LTTNG_UST_CTX_FIELD_PADDING     40
 252 struct lttng_ctx_field {
 253         struct lttng_event_field event_field;
 254         size_t (*get_size)(struct lttng_ctx_field *field, size_t offset);
 255         void (*record)(struct lttng_ctx_field *field,
 256                        struct lttng_ust_lib_ring_buffer_ctx *ctx,
 257                        struct lttng_channel *chan);
 258         void (*get_value)(struct lttng_ctx_field *field,
 259                          struct lttng_ctx_value *value);
 260         union {
 261                 struct lttng_perf_counter_field *perf_counter;
 262                 char padding[LTTNG_UST_CTX_FIELD_PADDING];
 263         } u;
 264         void (*destroy)(struct lttng_ctx_field *field);
 265         char *field_name;       /* Has ownership, dynamically allocated. */
 266 };
 267
 268 #define LTTNG_UST_CTX_PADDING   20
 269 struct lttng_ctx {
 270         struct lttng_ctx_field *fields;
 271         unsigned int nr_fields;
 272         unsigned int allocated_fields;
 273         unsigned int largest_align;
 274         char padding[LTTNG_UST_CTX_PADDING];
 275 };
 276
 277 /*
 278  * IMPORTANT: this structure is part of the ABI between the probe and
 279  * UST. Fields need to be only added at the end, never reordered, never
 280  * removed.
 281  *
 282  * The field @struct_size should be used to determine the size of the
 283  * structure. It should be queried before using additional fields added
 284  * at the end of the structure.
 285  */
 286 struct lttng_ust_event_desc {
 287         uint32_t struct_size;                   /* Size of this structure. */
 288         const char *name;
 289         void (*probe_callback)(void);
 290         const struct lttng_event_ctx *ctx;      /* context */
 291         const struct lttng_event_field *fields; /* event payload */
 292         unsigned int nr_fields;
 293         const int **loglevel;
 294         const char *signature;                  /* Argument types/names received */
 295         const char **model_emf_uri;
 296
 297         /* End of base ABI. Fields below should be used after checking struct_size. */
 298 };
 299
 300 /*
 301  * IMPORTANT: this structure is part of the ABI between the probe and
 302  * UST. Fields need to be only added at the end, never reordered, never
 303  * removed.
 304  *
 305  * The field @struct_size should be used to determine the size of the
 306  * structure. It should be queried before using additional fields added
 307  * at the end of the structure.
 308  */
 309 struct lttng_ust_probe_desc {
 310         uint32_t struct_size;                   /* Size of this structure. */
 311
 312         const char *provider;
 313         const struct lttng_ust_event_desc **event_desc;
 314         unsigned int nr_events;
 315         struct cds_list_head head;              /* chain registered probes */
 316         struct cds_list_head lazy_init_head;
 317         int lazy;                               /* lazy registration */
 318         uint32_t major;
 319         uint32_t minor;
 320
 321         /* End of base ABI. Fields below should be used after checking struct_size. */
 322 };
 323
 324 /* Data structures used by the tracer. */
 325
 326 /*
 327  * Bytecode interpreter return value masks.
 328  */
 329 enum lttng_bytecode_interpreter_ret {
 330         LTTNG_INTERPRETER_DISCARD = 0,
 331         LTTNG_INTERPRETER_RECORD_FLAG = (1ULL << 0),
 332         /* Other bits are kept for future use. */
 333 };
 334
 335 struct lttng_interpreter_output;
 336 struct lttng_ust_bytecode_runtime_private;
 337
 338 /*
 339  * This structure is used in the probes. More specifically, the
 340  * `interpreter_funcs` and `node` fields are explicity used in the
 341  * probes. When modifying this structure we must not change the layout
 342  * of these two fields as it is considered ABI.
 343  */
 344 struct lttng_bytecode_runtime {
 345         struct lttng_ust_bytecode_runtime_private *priv;
 346
 347         /* Associated bytecode */
 348         union {
 349                 uint64_t (*filter)(void *interpreter_data,
 350                                 const char *interpreter_stack_data);
 351                 uint64_t (*capture)(void *interpreter_data,
 352                                 const char *interpreter_stack_data,
 353                                 struct lttng_interpreter_output *interpreter_output);
 354         } interpreter_funcs;
 355         struct cds_list_head node;      /* list of bytecode runtime in event */
 356 };
 357
 358 /*
 359  * lttng_event structure is referred to by the tracing fast path. It
 360  * must be kept small.
 361  *
 362  * IMPORTANT: this structure is part of the ABI between the probe and
 363  * UST. Fields need to be only added at the end, never reordered, never
 364  * removed.
 365  */
 366
 367 struct lttng_ust_event_common_private;
 368
 369 enum lttng_ust_event_type {
 370         LTTNG_UST_EVENT_TYPE_RECORDER = 0,
 371         LTTNG_UST_EVENT_TYPE_NOTIFIER = 1,
 372 };
 373
 374 /*
 375  * IMPORTANT: this structure is part of the ABI between the probe and
 376  * UST. Fields need to be only added at the end, never reordered, never
 377  * removed.
 378  *
 379  * struct lttng_ust_event_common is the common ancestor of the various
 380  * public event actions. Inheritance is done by composition: The parent
 381  * has a pointer to its child, and the child has a pointer to its
 382  * parent. Inheritance of those public structures is done by composition
 383  * to ensure both parent and child structures can be extended.
 384  *
 385  * The field @struct_size should be used to determine the size of the
 386  * structure. It should be queried before using additional fields added
 387  * at the end of the structure.
 388  */
 389 struct lttng_ust_event_common {
 390         uint32_t struct_size;                           /* Size of this structure. */
 391         struct lttng_ust_event_common_private *priv;    /* Private event interface */
 392
 393         enum lttng_ust_event_type type;
 394         void *child;                                    /* Pointer to child, for inheritance by aggregation. */
 395
 396         int enabled;
 397         int has_enablers_without_bytecode;
 398         /* list of struct lttng_bytecode_runtime, sorted by seqnum */
 399         struct cds_list_head filter_bytecode_runtime_head;
 400
 401         /* End of base ABI. Fields below should be used after checking struct_size. */
 402 };
 403
 404 struct lttng_ust_event_recorder_private;
 405
 406 /*
 407  * IMPORTANT: this structure is part of the ABI between the probe and
 408  * UST. Fields need to be only added at the end, never reordered, never
 409  * removed.
 410  *
 411  * struct lttng_ust_event_recorder is the action for recording events
 412  * into a ring buffer. It inherits from struct lttng_ust_event_common
 413  * by composition to ensure both parent and child structure are
 414  * extensible.
 415  *
 416  * The field @struct_size should be used to determine the size of the
 417  * structure. It should be queried before using additional fields added
 418  * at the end of the structure.
 419  */
 420 struct lttng_ust_event_recorder {
 421         uint32_t struct_size;                           /* Size of this structure. */
 422         struct lttng_ust_event_common *parent;          /* Inheritance by aggregation. */
 423         struct lttng_ust_event_recorder_private *priv;  /* Private event record interface */
 424
 425         unsigned int id;
 426         struct lttng_channel *chan;
 427         struct lttng_ctx *ctx;
 428
 429         /* End of base ABI. Fields below should be used after checking struct_size. */
 430 };
 431
 432 struct lttng_ust_event_notifier_private;
 433
 434 /*
 435  * IMPORTANT: this structure is part of the ABI between the probe and
 436  * UST. Fields need to be only added at the end, never reordered, never
 437  * removed.
 438  *
 439  * struct lttng_ust_event_notifier is the action for sending
 440  * notifications. It inherits from struct lttng_ust_event_common
 441  * by composition to ensure both parent and child structure are
 442  * extensible.
 443  *
 444  * The field @struct_size should be used to determine the size of the
 445  * structure. It should be queried before using additional fields added
 446  * at the end of the structure.
 447  */
 448 struct lttng_ust_event_notifier {
 449         uint32_t struct_size;                           /* Size of this structure. */
 450         struct lttng_ust_event_common *parent;          /* Inheritance by aggregation. */
 451         struct lttng_ust_event_notifier_private *priv;  /* Private event notifier interface */
 452
 453         void (*notification_send)(struct lttng_ust_event_notifier *event_notifier,
 454                 const char *stack_data);
 455         struct cds_list_head capture_bytecode_runtime_head;
 456
 457         /* End of base ABI. Fields below should be used after checking struct_size. */
 458 };
 459
 460 struct lttng_enum {
 461         const struct lttng_enum_desc *desc;
 462         struct lttng_session *session;
 463         struct cds_list_head node;      /* Enum list in session */
 464         struct cds_hlist_node hlist;    /* Session ht of enums */
 465         uint64_t id;                    /* Enumeration ID in sessiond */
 466 };
 467
 468 struct channel;
 469 struct lttng_ust_shm_handle;
 470
 471 /*
 472  * IMPORTANT: this structure is part of the ABI between the probe and
 473  * UST. Fields need to be only added at the end, never reordered, never
 474  * removed.
 475  */
 476 struct lttng_channel_ops {
 477         struct lttng_channel *(*channel_create)(const char *name,
 478                         void *buf_addr,
 479                         size_t subbuf_size, size_t num_subbuf,
 480                         unsigned int switch_timer_interval,
 481                         unsigned int read_timer_interval,
 482                         unsigned char *uuid,
 483                         uint32_t chan_id,
 484                         const int *stream_fds, int nr_stream_fds,
 485                         int64_t blocking_timeout);
 486         void (*channel_destroy)(struct lttng_channel *chan);
 487         int (*event_reserve)(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 488                              uint32_t event_id);
 489         void (*event_commit)(struct lttng_ust_lib_ring_buffer_ctx *ctx);
 490         void (*event_write)(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 491                         const void *src, size_t len);
 492         /*
 493          * packet_avail_size returns the available size in the current
 494          * packet. Note that the size returned is only a hint, since it
 495          * may change due to concurrent writes.
 496          */
 497         size_t (*packet_avail_size)(struct channel *chan,
 498                                     struct lttng_ust_shm_handle *handle);
 499         int (*is_finalized)(struct channel *chan);
 500         int (*is_disabled)(struct channel *chan);
 501         int (*flush_buffer)(struct channel *chan, struct lttng_ust_shm_handle *handle);
 502         void (*event_strcpy)(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 503                         const char *src, size_t len);
 504 };
 505
 506 /*
 507  * IMPORTANT: this structure is part of the ABI between the probe and
 508  * UST. Fields need to be only added at the end, never reordered, never
 509  * removed.
 510  */
 511 struct lttng_channel {
 512         /*
 513          * The pointers located in this private data are NOT safe to be
 514          * dereferenced by the consumer. The only operations the
 515          * consumer process is designed to be allowed to do is to read
 516          * and perform subbuffer flush.
 517          */
 518         struct channel *chan;           /* Channel buffers */
 519         int enabled;
 520         struct lttng_ctx *ctx;
 521         /* Event ID management */
 522         struct lttng_session *session;
 523         int objd;                       /* Object associated to channel */
 524         struct cds_list_head node;      /* Channel list in session */
 525         const struct lttng_channel_ops *ops;
 526         int header_type;                /* 0: unset, 1: compact, 2: large */
 527         struct lttng_ust_shm_handle *handle;    /* shared-memory handle */
 528
 529         /* Channel ID */
 530         unsigned int id;
 531         enum lttng_ust_abi_chan_type type;
 532         unsigned char uuid[LTTNG_UST_UUID_LEN]; /* Trace session unique ID */
 533         int tstate:1;                   /* Transient enable state */
 534 };
 535
 536 struct lttng_counter_dimension;
 537
 538 struct lttng_counter_ops {
 539         struct lib_counter *(*counter_create)(size_t nr_dimensions,
 540                         const struct lttng_counter_dimension *dimensions,
 541                         int64_t global_sum_step,
 542                         int global_counter_fd,
 543                         int nr_counter_cpu_fds,
 544                         const int *counter_cpu_fds,
 545                         bool is_daemon);
 546         void (*counter_destroy)(struct lib_counter *counter);
 547         int (*counter_add)(struct lib_counter *counter,
 548                         const size_t *dimension_indexes, int64_t v);
 549         int (*counter_read)(struct lib_counter *counter,
 550                         const size_t *dimension_indexes, int cpu,
 551                         int64_t *value, bool *overflow, bool *underflow);
 552         int (*counter_aggregate)(struct lib_counter *counter,
 553                         const size_t *dimension_indexes, int64_t *value,
 554                         bool *overflow, bool *underflow);
 555         int (*counter_clear)(struct lib_counter *counter, const size_t *dimension_indexes);
 556 };
 557
 558 #define LTTNG_UST_STACK_CTX_PADDING     32
 559 struct lttng_stack_ctx {
 560         struct lttng_ust_event_recorder *event_recorder;
 561         struct lttng_ctx *chan_ctx;     /* RCU dereferenced. */
 562         struct lttng_ctx *event_ctx;    /* RCU dereferenced. */
 563         char padding[LTTNG_UST_STACK_CTX_PADDING];
 564 };
 565
 566 #define LTTNG_UST_EVENT_HT_BITS         12
 567 #define LTTNG_UST_EVENT_HT_SIZE         (1U << LTTNG_UST_EVENT_HT_BITS)
 568
 569 struct lttng_ust_event_ht {
 570         struct cds_hlist_head table[LTTNG_UST_EVENT_HT_SIZE];
 571 };
 572
 573 #define LTTNG_UST_EVENT_NOTIFIER_HT_BITS                12
 574 #define LTTNG_UST_EVENT_NOTIFIER_HT_SIZE                (1U << LTTNG_UST_EVENT_NOTIFIER_HT_BITS)
 575 struct lttng_ust_event_notifier_ht {
 576         struct cds_hlist_head table[LTTNG_UST_EVENT_NOTIFIER_HT_SIZE];
 577 };
 578
 579 #define LTTNG_UST_ENUM_HT_BITS          12
 580 #define LTTNG_UST_ENUM_HT_SIZE          (1U << LTTNG_UST_ENUM_HT_BITS)
 581
 582 struct lttng_ust_enum_ht {
 583         struct cds_hlist_head table[LTTNG_UST_ENUM_HT_SIZE];
 584 };
 585
 586 struct lttng_ust_session_private;
 587
 588 /*
 589  * IMPORTANT: this structure is part of the ABI between the probe and
 590  * UST. Fields need to be only added at the end, never reordered, never
 591  * removed.
 592  *
 593  * The field @struct_size should be used to determine the size of the
 594  * structure. It should be queried before using additional fields added
 595  * at the end of the structure.
 596  */
 597 struct lttng_session {
 598         uint32_t struct_size;                   /* Size of this structure */
 599         struct lttng_ust_session_private *priv; /* Private session interface */
 600
 601         int active;                             /* Is trace session active ? */
 602
 603         /* End of base ABI. Fields below should be used after checking struct_size. */
 604 };
 605
 606 int lttng_ust_probe_register(struct lttng_ust_probe_desc *desc);
 607 void lttng_ust_probe_unregister(struct lttng_ust_probe_desc *desc);
 608
 609 /*
 610  * Can be used by applications that change their procname to clear the ust cached value.
 611  */
 612 void lttng_context_procname_reset(void);
 613
 614 struct lttng_transport *lttng_transport_find(const char *name);
 615
 616 int lttng_session_active(void);
 617
 618 void lttng_ust_dl_update(void *ip);
 619
 620 #ifdef __cplusplus
 621 }
 622 #endif
 623
 624 #endif /* _LTTNG_UST_EVENTS_H */