include/lttng/ust-events.h

   1 #ifndef _LTTNG_UST_EVENTS_H
   2 #define _LTTNG_UST_EVENTS_H
   3
   4 /*
   5  * lttng/ust-events.h
   6  *
   7  * Copyright 2010-2012 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * Holds LTTng per-session event registry.
  10  *
  11  * Permission is hereby granted, free of charge, to any person obtaining a copy
  12  * of this software and associated documentation files (the "Software"), to deal
  13  * in the Software without restriction, including without limitation the rights
  14  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  15  * copies of the Software, and to permit persons to whom the Software is
  16  * furnished to do so, subject to the following conditions:
  17  *
  18  * The above copyright notice and this permission notice shall be included in
  19  * all copies or substantial portions of the Software.
  20  *
  21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  22  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  23  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  24  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  25  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  26  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  27  * SOFTWARE.
  28  */
  29
  30 #include <urcu/list.h>
  31 #include <urcu/hlist.h>
  32 #include <stdint.h>
  33 #include <lttng/ust-abi.h>
  34 #include <lttng/ust-tracer.h>
  35 #include <lttng/ust-endian.h>
  36 #include <float.h>
  37
  38 #define LTTNG_UST_UUID_LEN              16
  39
  40 /*
  41  * Tracepoint provider version. Compatibility based on the major number.
  42  * Older tracepoint providers can always register to newer lttng-ust
  43  * library, but the opposite is rejected: a newer tracepoint provider is
  44  * rejected by an older lttng-ust library.
  45  */
  46 #define LTTNG_UST_PROVIDER_MAJOR        1
  47 #define LTTNG_UST_PROVIDER_MINOR        0
  48
  49 struct lttng_channel;
  50 struct lttng_session;
  51 struct lttng_ust_lib_ring_buffer_ctx;
  52
  53 /*
  54  * Data structures used by tracepoint event declarations, and by the
  55  * tracer. Those structures have padding for future extension.
  56  */
  57
  58 /*
  59  * LTTng client type enumeration. Used by the consumer to map the
  60  * callbacks from its own address space.
  61  */
  62 enum lttng_client_types {
  63         LTTNG_CLIENT_METADATA = 0,
  64         LTTNG_CLIENT_DISCARD = 1,
  65         LTTNG_CLIENT_OVERWRITE = 2,
  66         LTTNG_CLIENT_DISCARD_RT = 3,
  67         LTTNG_CLIENT_OVERWRITE_RT = 4,
  68         LTTNG_NR_CLIENT_TYPES,
  69 };
  70
  71 /* Type description */
  72
  73 /* Update the astract_types name table in lttng-types.c along with this enum */
  74 enum lttng_abstract_types {
  75         atype_integer,
  76         atype_enum,
  77         atype_array,
  78         atype_sequence,
  79         atype_string,
  80         atype_float,
  81         NR_ABSTRACT_TYPES,
  82 };
  83
  84 /* Update the string_encodings name table in lttng-types.c along with this enum */
  85 enum lttng_string_encodings {
  86         lttng_encode_none = 0,
  87         lttng_encode_UTF8 = 1,
  88         lttng_encode_ASCII = 2,
  89         NR_STRING_ENCODINGS,
  90 };
  91
  92 #define LTTNG_UST_ENUM_ENTRY_PADDING    16
  93 struct lttng_enum_entry {
  94         unsigned long long start, end;  /* start and end are inclusive */
  95         const char *string;
  96         char padding[LTTNG_UST_ENUM_ENTRY_PADDING];
  97 };
  98
  99 #define __type_integer(_type, _byte_order, _base, _encoding)    \
 100         {                                                       \
 101           .atype = atype_integer,                               \
 102           .u =                                                  \
 103                 {                                               \
 104                   .basic =                                      \
 105                         {                                       \
 106                           .integer =                            \
 107                                 {                               \
 108                                   .size = sizeof(_type) * CHAR_BIT,             \
 109                                   .alignment = lttng_alignof(_type) * CHAR_BIT, \
 110                                   .signedness = lttng_is_signed_type(_type),    \
 111                                   .reverse_byte_order = _byte_order != BYTE_ORDER, \
 112                                   .base = _base,                                \
 113                                   .encoding = lttng_encode_##_encoding,         \
 114                                 }                               \
 115                         }                                       \
 116                 },                                              \
 117         }                                                       \
 118
 119 #define LTTNG_UST_INTEGER_TYPE_PADDING  24
 120 struct lttng_integer_type {
 121         unsigned int size;              /* in bits */
 122         unsigned short alignment;       /* in bits */
 123         unsigned int signedness:1;
 124         unsigned int reverse_byte_order:1;
 125         unsigned int base;              /* 2, 8, 10, 16, for pretty print */
 126         enum lttng_string_encodings encoding;
 127         char padding[LTTNG_UST_INTEGER_TYPE_PADDING];
 128 };
 129
 130 /*
 131  * Only float and double are supported. long double is not supported at
 132  * the moment.
 133  */
 134 #define _float_mant_dig(_type)                                          \
 135         (sizeof(_type) == sizeof(float) ? FLT_MANT_DIG                  \
 136                 : (sizeof(_type) == sizeof(double) ? DBL_MANT_DIG       \
 137                 : 0))
 138
 139 #define __type_float(_type)                                     \
 140         {                                                       \
 141           .atype = atype_float,                                 \
 142           .u =                                                  \
 143                 {                                               \
 144                   .basic =                                      \
 145                         {                                       \
 146                           ._float =                             \
 147                                 {                               \
 148                                   .exp_dig = sizeof(_type) * CHAR_BIT           \
 149                                                   - _float_mant_dig(_type),     \
 150                                   .mant_dig = _float_mant_dig(_type),           \
 151                                   .alignment = lttng_alignof(_type) * CHAR_BIT, \
 152                                   .reverse_byte_order = BYTE_ORDER != FLOAT_WORD_ORDER, \
 153                                 }                               \
 154                         }                                       \
 155                 },                                              \
 156         }                                                       \
 157
 158 #define LTTNG_UST_FLOAT_TYPE_PADDING    24
 159 struct lttng_float_type {
 160         unsigned int exp_dig;           /* exponent digits, in bits */
 161         unsigned int mant_dig;          /* mantissa digits, in bits */
 162         unsigned short alignment;       /* in bits */
 163         unsigned int reverse_byte_order:1;
 164         char padding[LTTNG_UST_FLOAT_TYPE_PADDING];
 165 };
 166
 167 #define LTTNG_UST_BASIC_TYPE_PADDING    128
 168 union _lttng_basic_type {
 169         struct lttng_integer_type integer;
 170         struct {
 171                 const char *name;
 172         } enumeration;
 173         struct {
 174                 enum lttng_string_encodings encoding;
 175         } string;
 176         struct lttng_float_type _float;
 177         char padding[LTTNG_UST_BASIC_TYPE_PADDING];
 178 };
 179
 180 struct lttng_basic_type {
 181         enum lttng_abstract_types atype;
 182         union {
 183                 union _lttng_basic_type basic;
 184         } u;
 185 };
 186
 187 #define LTTNG_UST_TYPE_PADDING  128
 188 struct lttng_type {
 189         enum lttng_abstract_types atype;
 190         union {
 191                 union _lttng_basic_type basic;
 192                 struct {
 193                         struct lttng_basic_type elem_type;
 194                         unsigned int length;            /* num. elems. */
 195                 } array;
 196                 struct {
 197                         struct lttng_basic_type length_type;
 198                         struct lttng_basic_type elem_type;
 199                 } sequence;
 200                 char padding[LTTNG_UST_TYPE_PADDING];
 201         } u;
 202 };
 203
 204 #define LTTNG_UST_ENUM_TYPE_PADDING     24
 205 struct lttng_enum {
 206         const char *name;
 207         struct lttng_type container_type;
 208         const struct lttng_enum_entry *entries;
 209         unsigned int len;
 210         char padding[LTTNG_UST_ENUM_TYPE_PADDING];
 211 };
 212
 213 /*
 214  * Event field description
 215  *
 216  * IMPORTANT: this structure is part of the ABI between the probe and
 217  * UST. Fields need to be only added at the end, never reordered, never
 218  * removed.
 219  */
 220
 221 #define LTTNG_UST_EVENT_FIELD_PADDING   28
 222 struct lttng_event_field {
 223         const char *name;
 224         struct lttng_type type;
 225         unsigned int nowrite;   /* do not write into trace */
 226         char padding[LTTNG_UST_EVENT_FIELD_PADDING];
 227 };
 228
 229 union lttng_ctx_value {
 230         int64_t s64;
 231         const char *str;
 232         double d;
 233 };
 234
 235 #define LTTNG_UST_CTX_FIELD_PADDING     40
 236 struct lttng_ctx_field {
 237         struct lttng_event_field event_field;
 238         size_t (*get_size)(size_t offset);
 239         void (*record)(struct lttng_ctx_field *field,
 240                        struct lttng_ust_lib_ring_buffer_ctx *ctx,
 241                        struct lttng_channel *chan);
 242         void (*get_value)(struct lttng_ctx_field *field,
 243                          union lttng_ctx_value *value);
 244         union {
 245                 char padding[LTTNG_UST_CTX_FIELD_PADDING];
 246         } u;
 247         void (*destroy)(struct lttng_ctx_field *field);
 248 };
 249
 250 #define LTTNG_UST_CTX_PADDING   24
 251 struct lttng_ctx {
 252         struct lttng_ctx_field *fields;
 253         unsigned int nr_fields;
 254         unsigned int allocated_fields;
 255         char padding[LTTNG_UST_CTX_PADDING];
 256 };
 257
 258 #define LTTNG_UST_EVENT_DESC_PADDING    40
 259 struct lttng_event_desc {
 260         const char *name;
 261         void (*probe_callback)(void);
 262         const struct lttng_event_ctx *ctx;      /* context */
 263         const struct lttng_event_field *fields; /* event payload */
 264         unsigned int nr_fields;
 265         const int **loglevel;
 266         const char *signature;  /* Argument types/names received */
 267         union {
 268                 struct {
 269                         const char **model_emf_uri;
 270                 } ext;
 271                 char padding[LTTNG_UST_EVENT_DESC_PADDING];
 272         } u;
 273 };
 274
 275 #define LTTNG_UST_PROBE_DESC_PADDING    12
 276 struct lttng_probe_desc {
 277         const char *provider;
 278         const struct lttng_event_desc **event_desc;
 279         unsigned int nr_events;
 280         struct cds_list_head head;              /* chain registered probes */
 281         struct cds_list_head lazy_init_head;
 282         int lazy;                               /* lazy registration */
 283         uint32_t major;
 284         uint32_t minor;
 285         char padding[LTTNG_UST_PROBE_DESC_PADDING];
 286 };
 287
 288 /* Data structures used by the tracer. */
 289
 290 enum lttng_enabler_type {
 291         LTTNG_ENABLER_WILDCARD,
 292         LTTNG_ENABLER_EVENT,
 293 };
 294
 295 /*
 296  * Enabler field, within whatever object is enabling an event. Target of
 297  * backward reference.
 298  */
 299 struct lttng_enabler {
 300         enum lttng_enabler_type type;
 301
 302         /* head list of struct lttng_ust_filter_bytecode_node */
 303         struct cds_list_head filter_bytecode_head;
 304         struct cds_list_head node;      /* per-session list of enablers */
 305
 306         struct lttng_ust_event event_param;
 307         struct lttng_channel *chan;
 308         struct lttng_ctx *ctx;
 309         unsigned int enabled:1;
 310 };
 311
 312 struct tp_list_entry {
 313         struct lttng_ust_tracepoint_iter tp;
 314         struct cds_list_head head;
 315 };
 316
 317 struct lttng_ust_tracepoint_list {
 318         struct tp_list_entry *iter;
 319         struct cds_list_head head;
 320 };
 321
 322 struct tp_field_list_entry {
 323         struct lttng_ust_field_iter field;
 324         struct cds_list_head head;
 325 };
 326
 327 struct lttng_ust_field_list {
 328         struct tp_field_list_entry *iter;
 329         struct cds_list_head head;
 330 };
 331
 332 struct ust_pending_probe;
 333 struct lttng_event;
 334
 335 struct lttng_ust_filter_bytecode_node {
 336         struct cds_list_head node;
 337         struct lttng_enabler *enabler;
 338         /*
 339          * struct lttng_ust_filter_bytecode has var. sized array, must
 340          * be last field.
 341          */
 342         struct lttng_ust_filter_bytecode bc;
 343 };
 344
 345 /*
 346  * Filter return value masks.
 347  */
 348 enum lttng_filter_ret {
 349         LTTNG_FILTER_DISCARD = 0,
 350         LTTNG_FILTER_RECORD_FLAG = (1ULL << 0),
 351         /* Other bits are kept for future use. */
 352 };
 353
 354 struct lttng_bytecode_runtime {
 355         /* Associated bytecode */
 356         struct lttng_ust_filter_bytecode_node *bc;
 357         uint64_t (*filter)(void *filter_data, const char *filter_stack_data);
 358         int link_failed;
 359         struct cds_list_head node;      /* list of bytecode runtime in event */
 360 };
 361
 362 /*
 363  * Objects in a linked-list of enablers, owned by an event.
 364  */
 365 struct lttng_enabler_ref {
 366         struct cds_list_head node;              /* enabler ref list */
 367         struct lttng_enabler *ref;              /* backward ref */
 368 };
 369
 370 /*
 371  * lttng_event structure is referred to by the tracing fast path. It
 372  * must be kept small.
 373  *
 374  * IMPORTANT: this structure is part of the ABI between the probe and
 375  * UST. Fields need to be only added at the end, never reordered, never
 376  * removed.
 377  */
 378 struct lttng_event {
 379         /* LTTng-UST 2.0 starts here */
 380         unsigned int id;
 381         struct lttng_channel *chan;
 382         int enabled;
 383         const struct lttng_event_desc *desc;
 384         void *_deprecated1;
 385         struct lttng_ctx *ctx;
 386         enum lttng_ust_instrumentation instrumentation;
 387         union {
 388         } u;
 389         struct cds_list_head node;              /* Event list in session */
 390         struct cds_list_head _deprecated2;
 391         void *_deprecated3;
 392         unsigned int _deprecated4:1;
 393
 394         /* LTTng-UST 2.1 starts here */
 395         /* list of struct lttng_bytecode_runtime, sorted by seqnum */
 396         struct cds_list_head bytecode_runtime_head;
 397         int has_enablers_without_bytecode;
 398         /* Backward references: list of lttng_enabler_ref (ref to enablers) */
 399         struct cds_list_head enablers_ref_head;
 400         struct cds_hlist_node hlist;    /* session ht of events */
 401         int registered;                 /* has reg'd tracepoint probe */
 402 };
 403
 404 struct channel;
 405 struct lttng_ust_shm_handle;
 406
 407 /*
 408  * IMPORTANT: this structure is part of the ABI between the probe and
 409  * UST. Fields need to be only added at the end, never reordered, never
 410  * removed.
 411  */
 412 struct lttng_channel_ops {
 413         struct lttng_channel *(*channel_create)(const char *name,
 414                         void *buf_addr,
 415                         size_t subbuf_size, size_t num_subbuf,
 416                         unsigned int switch_timer_interval,
 417                         unsigned int read_timer_interval,
 418                         unsigned char *uuid,
 419                         uint32_t chan_id);
 420         void (*channel_destroy)(struct lttng_channel *chan);
 421         void *_deprecated1;
 422         void *_deprecated2;
 423         int (*event_reserve)(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 424                              uint32_t event_id);
 425         void (*event_commit)(struct lttng_ust_lib_ring_buffer_ctx *ctx);
 426         void (*event_write)(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 427                         const void *src, size_t len);
 428         /*
 429          * packet_avail_size returns the available size in the current
 430          * packet. Note that the size returned is only a hint, since it
 431          * may change due to concurrent writes.
 432          */
 433         size_t (*packet_avail_size)(struct channel *chan,
 434                                     struct lttng_ust_shm_handle *handle);
 435         //wait_queue_head_t *(*get_reader_wait_queue)(struct channel *chan);
 436         //wait_queue_head_t *(*get_hp_wait_queue)(struct channel *chan);
 437         int (*is_finalized)(struct channel *chan);
 438         int (*is_disabled)(struct channel *chan);
 439         int (*flush_buffer)(struct channel *chan, struct lttng_ust_shm_handle *handle);
 440 };
 441
 442 /*
 443  * IMPORTANT: this structure is part of the ABI between the probe and
 444  * UST. Fields need to be only added at the end, never reordered, never
 445  * removed.
 446  */
 447 struct lttng_channel {
 448         /*
 449          * The pointers located in this private data are NOT safe to be
 450          * dereferenced by the consumer. The only operations the
 451          * consumer process is designed to be allowed to do is to read
 452          * and perform subbuffer flush.
 453          */
 454         struct channel *chan;           /* Channel buffers */
 455         int enabled;
 456         struct lttng_ctx *ctx;
 457         /* Event ID management */
 458         struct lttng_session *session;
 459         int objd;                       /* Object associated to channel */
 460         unsigned int _deprecated1;
 461         unsigned int _deprecated2;
 462         struct cds_list_head node;      /* Channel list in session */
 463         const struct lttng_channel_ops *ops;
 464         int header_type;                /* 0: unset, 1: compact, 2: large */
 465         struct lttng_ust_shm_handle *handle;    /* shared-memory handle */
 466         unsigned int _deprecated3:1;
 467
 468         /* Channel ID */
 469         unsigned int id;
 470         enum lttng_ust_chan_type type;
 471         unsigned char uuid[LTTNG_UST_UUID_LEN]; /* Trace session unique ID */
 472         int tstate:1;                   /* Transient enable state */
 473 };
 474
 475 #define LTTNG_UST_EVENT_HT_BITS         12
 476 #define LTTNG_UST_EVENT_HT_SIZE         (1U << LTTNG_UST_EVENT_HT_BITS)
 477
 478 struct lttng_ust_event_ht {
 479         struct cds_hlist_head table[LTTNG_UST_EVENT_HT_SIZE];
 480 };
 481
 482 /*
 483  * IMPORTANT: this structure is part of the ABI between the probe and
 484  * UST. Fields need to be only added at the end, never reordered, never
 485  * removed.
 486  */
 487 struct lttng_session {
 488         int active;                             /* Is trace session active ? */
 489         int been_active;                        /* Been active ? */
 490         int objd;                               /* Object associated */
 491         void *_deprecated1;
 492         struct cds_list_head chan_head;         /* Channel list head */
 493         struct cds_list_head events_head;       /* list of events */
 494         struct cds_list_head _deprecated2;
 495         struct cds_list_head node;              /* Session list */
 496         int _deprecated3;
 497         unsigned int _deprecated4:1;
 498
 499         /* New UST 2.1 */
 500         /* List of enablers */
 501         struct cds_list_head enablers_head;
 502         struct lttng_ust_event_ht events_ht;    /* ht of events */
 503         void *owner;                            /* object owner */
 504         int tstate:1;                           /* Transient enable state */
 505 };
 506
 507 struct lttng_transport {
 508         char *name;
 509         struct cds_list_head node;
 510         struct lttng_channel_ops ops;
 511         const struct lttng_ust_lib_ring_buffer_config *client_config;
 512 };
 513
 514 struct lttng_session *lttng_session_create(void);
 515 int lttng_session_enable(struct lttng_session *session);
 516 int lttng_session_disable(struct lttng_session *session);
 517 void lttng_session_destroy(struct lttng_session *session);
 518
 519 struct lttng_channel *lttng_channel_create(struct lttng_session *session,
 520                                        const char *transport_name,
 521                                        void *buf_addr,
 522                                        size_t subbuf_size, size_t num_subbuf,
 523                                        unsigned int switch_timer_interval,
 524                                        unsigned int read_timer_interval,
 525                                        int **shm_fd, int **wait_fd,
 526                                        uint64_t **memory_map_size,
 527                                        struct lttng_channel *chan_priv_init);
 528
 529 int lttng_channel_enable(struct lttng_channel *channel);
 530 int lttng_channel_disable(struct lttng_channel *channel);
 531
 532 struct lttng_enabler *lttng_enabler_create(enum lttng_enabler_type type,
 533                 struct lttng_ust_event *event_param,
 534                 struct lttng_channel *chan);
 535 int lttng_enabler_enable(struct lttng_enabler *enabler);
 536 int lttng_enabler_disable(struct lttng_enabler *enabler);
 537 int lttng_enabler_attach_bytecode(struct lttng_enabler *enabler,
 538                 struct lttng_ust_filter_bytecode_node *bytecode);
 539 int lttng_enabler_attach_context(struct lttng_enabler *enabler,
 540                 struct lttng_ust_context *ctx);
 541
 542 int lttng_attach_context(struct lttng_ust_context *context_param,
 543                 struct lttng_ctx **ctx, struct lttng_session *session);
 544 void lttng_context_init(void);
 545 void lttng_context_exit(void);
 546 struct lttng_ctx *lttng_static_ctx;     /* Used by filtering */
 547
 548 void lttng_transport_register(struct lttng_transport *transport);
 549 void lttng_transport_unregister(struct lttng_transport *transport);
 550
 551 void synchronize_trace(void);
 552
 553 int lttng_probe_register(struct lttng_probe_desc *desc);
 554 void lttng_probe_unregister(struct lttng_probe_desc *desc);
 555 int lttng_fix_pending_events(void);
 556 int lttng_probes_init(void);
 557 void lttng_probes_exit(void);
 558 int lttng_find_context(struct lttng_ctx *ctx, const char *name);
 559 int lttng_get_context_index(struct lttng_ctx *ctx, const char *name);
 560 struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p);
 561 void lttng_remove_context_field(struct lttng_ctx **ctx_p,
 562                                 struct lttng_ctx_field *field);
 563 void lttng_destroy_context(struct lttng_ctx *ctx);
 564 int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx);
 565 int lttng_add_vpid_to_ctx(struct lttng_ctx **ctx);
 566 int lttng_add_pthread_id_to_ctx(struct lttng_ctx **ctx);
 567 int lttng_add_procname_to_ctx(struct lttng_ctx **ctx);
 568 int lttng_add_ip_to_ctx(struct lttng_ctx **ctx);
 569 void lttng_context_vtid_reset(void);
 570 void lttng_context_vpid_reset(void);
 571
 572 extern const struct lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_metadata;
 573 extern const struct lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_discard;
 574 extern const struct lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_overwrite;
 575
 576 struct lttng_transport *lttng_transport_find(const char *name);
 577
 578 int lttng_probes_get_event_list(struct lttng_ust_tracepoint_list *list);
 579 void lttng_probes_prune_event_list(struct lttng_ust_tracepoint_list *list);
 580 struct lttng_ust_tracepoint_iter *
 581         lttng_ust_tracepoint_list_get_iter_next(struct lttng_ust_tracepoint_list *list);
 582 int lttng_probes_get_field_list(struct lttng_ust_field_list *list);
 583 void lttng_probes_prune_field_list(struct lttng_ust_field_list *list);
 584 struct lttng_ust_field_iter *
 585         lttng_ust_field_list_get_iter_next(struct lttng_ust_field_list *list);
 586
 587 void lttng_filter_event_link_bytecode(struct lttng_event *event);
 588 void lttng_enabler_event_link_bytecode(struct lttng_event *event,
 589                 struct lttng_enabler *enabler);
 590 void lttng_free_event_filter_runtime(struct lttng_event *event);
 591 void lttng_filter_sync_state(struct lttng_bytecode_runtime *runtime);
 592
 593 struct cds_list_head *lttng_get_probe_list_head(void);
 594 int lttng_session_active(void);
 595
 596 #endif /* _LTTNG_UST_EVENTS_H */