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 <stddef.h>
  13 #include <stdint.h>
  14 #include <lttng/ust-abi.h>
  15 #include <lttng/ust-tracer.h>
  16 #include <lttng/ust-endian.h>
  17 #include <float.h>
  18 #include <errno.h>
  19 #include <urcu/ref.h>
  20 #include <pthread.h>
  21 #include <limits.h>
  22
  23 #ifdef __cplusplus
  24 extern "C" {
  25 #endif
  26
  27 #define LTTNG_UST_UUID_LEN              16
  28
  29 /*
  30  * Tracepoint provider version. Compatibility based on the major number.
  31  * Older tracepoint providers can always register to newer lttng-ust
  32  * library, but the opposite is rejected: a newer tracepoint provider is
  33  * rejected by an older lttng-ust library.
  34  */
  35 #define LTTNG_UST_PROVIDER_MAJOR        2
  36 #define LTTNG_UST_PROVIDER_MINOR        0
  37
  38 struct lttng_ust_channel_buffer;
  39 struct lttng_ust_session;
  40 struct lttng_ust_lib_ring_buffer_ctx;
  41 struct lttng_ust_event_field;
  42 struct lttng_ust_registered_probe;
  43
  44 /*
  45  * Data structures used by tracepoint event declarations, and by the
  46  * tracer.
  47  */
  48
  49 /* Type description */
  50
  51 enum lttng_ust_type {
  52         lttng_ust_type_integer,
  53         lttng_ust_type_string,
  54         lttng_ust_type_float,
  55         lttng_ust_type_dynamic,
  56         lttng_ust_type_enum,
  57         lttng_ust_type_array,
  58         lttng_ust_type_sequence,
  59         lttng_ust_type_struct,
  60         NR_LTTNG_UST_TYPE,
  61 };
  62
  63 enum lttng_ust_string_encoding {
  64         lttng_ust_string_encoding_none = 0,
  65         lttng_ust_string_encoding_UTF8 = 1,
  66         lttng_ust_string_encoding_ASCII = 2,
  67         NR_LTTNG_UST_STRING_ENCODING,
  68 };
  69
  70 struct lttng_ust_enum_value {
  71         unsigned long long value;
  72         unsigned int signedness:1;
  73 };
  74
  75 enum lttng_ust_enum_entry_option {
  76         LTTNG_UST_ENUM_ENTRY_OPTION_IS_AUTO = 1U << 0,
  77 };
  78
  79 /*
  80  * Enumeration entry description
  81  *
  82  * IMPORTANT: this structure is part of the ABI between the probe and
  83  * UST. Fields need to be only added at the end, never reordered, never
  84  * removed.
  85  *
  86  * The field @struct_size should be used to determine the size of the
  87  * structure. It should be queried before using additional fields added
  88  * at the end of the structure.
  89  */
  90
  91 struct lttng_ust_enum_entry {
  92         uint32_t struct_size;
  93
  94         struct lttng_ust_enum_value start, end; /* start and end are inclusive */
  95         const char *string;
  96         unsigned int options;
  97
  98         /* End of base ABI. Fields below should be used after checking struct_size. */
  99 };
 100
 101 /*
 102  * struct lttng_ust_type_common is fixed-size. Its children inherits
 103  * from it by embedding struct lttng_ust_type_common as its first field.
 104  */
 105 struct lttng_ust_type_common {
 106         enum lttng_ust_type type;
 107 };
 108
 109 struct lttng_ust_type_integer {
 110         struct lttng_ust_type_common parent;
 111         uint32_t struct_size;
 112         unsigned int size;              /* in bits */
 113         unsigned short alignment;       /* in bits */
 114         unsigned int signedness:1;
 115         unsigned int reverse_byte_order:1;
 116         unsigned int base;              /* 2, 8, 10, 16, for pretty print */
 117 };
 118
 119 #define lttng_ust_type_integer_define(_type, _byte_order, _base)        \
 120         ((struct lttng_ust_type_common *) __LTTNG_COMPOUND_LITERAL(struct lttng_ust_type_integer, { \
 121                 .parent = {                                             \
 122                         .type = lttng_ust_type_integer,                 \
 123                 },                                                      \
 124                 .struct_size = sizeof(struct lttng_ust_type_integer),   \
 125                 .size = sizeof(_type) * CHAR_BIT,                       \
 126                 .alignment = lttng_ust_rb_alignof(_type) * CHAR_BIT,    \
 127                 .signedness = lttng_ust_is_signed_type(_type),          \
 128                 .reverse_byte_order = _byte_order != BYTE_ORDER,        \
 129                 .base = _base,                                          \
 130         }))
 131
 132 struct lttng_ust_type_float {
 133         struct lttng_ust_type_common parent;
 134         uint32_t struct_size;
 135         unsigned int exp_dig;           /* exponent digits, in bits */
 136         unsigned int mant_dig;          /* mantissa digits, in bits */
 137         unsigned short alignment;       /* in bits */
 138         unsigned int reverse_byte_order:1;
 139 };
 140
 141 /*
 142  * Only float and double are supported. long double is not supported at
 143  * the moment.
 144  */
 145 #define lttng_ust_float_mant_dig(_type)                                 \
 146         (sizeof(_type) == sizeof(float) ? FLT_MANT_DIG                  \
 147                 : (sizeof(_type) == sizeof(double) ? DBL_MANT_DIG       \
 148                 : 0))
 149
 150 #define lttng_ust_type_float_define(_type)                              \
 151         ((struct lttng_ust_type_common *) __LTTNG_COMPOUND_LITERAL(struct lttng_ust_type_float, { \
 152                 .parent = {                                             \
 153                         .type = lttng_ust_type_float,                   \
 154                 },                                                      \
 155                 .struct_size = sizeof(struct lttng_ust_type_float),     \
 156                 .exp_dig = sizeof(_type) * CHAR_BIT                     \
 157                         - lttng_ust_float_mant_dig(_type),              \
 158                 .mant_dig = lttng_ust_float_mant_dig(_type),            \
 159                 .alignment = lttng_ust_rb_alignof(_type) * CHAR_BIT,    \
 160                 .reverse_byte_order = BYTE_ORDER != FLOAT_WORD_ORDER,   \
 161         }))
 162
 163
 164 struct lttng_ust_type_string {
 165         struct lttng_ust_type_common parent;
 166         uint32_t struct_size;
 167         enum lttng_ust_string_encoding encoding;
 168 };
 169
 170 struct lttng_ust_type_enum {
 171         struct lttng_ust_type_common parent;
 172         uint32_t struct_size;
 173         const struct lttng_ust_enum_desc *desc; /* Enumeration mapping */
 174         const struct lttng_ust_type_common *container_type;
 175 };
 176
 177 struct lttng_ust_type_array {
 178         struct lttng_ust_type_common parent;
 179         uint32_t struct_size;
 180         const struct lttng_ust_type_common *elem_type;
 181         unsigned int length;                    /* Num. elems. */
 182         unsigned int alignment;
 183         enum lttng_ust_string_encoding encoding;
 184 };
 185
 186 struct lttng_ust_type_sequence {
 187         struct lttng_ust_type_common parent;
 188         uint32_t struct_size;
 189         const char *length_name;        /* Length field name. */
 190         const struct lttng_ust_type_common *elem_type;
 191         unsigned int alignment;         /* Alignment before elements. */
 192         enum lttng_ust_string_encoding encoding;
 193 };
 194
 195 struct lttng_ust_type_struct {
 196         struct lttng_ust_type_common parent;
 197         uint32_t struct_size;
 198         unsigned int nr_fields;
 199         const struct lttng_ust_event_field **fields;    /* Array of pointers to fields. */
 200         unsigned int alignment;
 201 };
 202
 203 /*
 204  * Enumeration description
 205  *
 206  * IMPORTANT: this structure is part of the ABI between the probe and
 207  * UST. Fields need to be only added at the end, never reordered, never
 208  * removed.
 209  *
 210  * The field @struct_size should be used to determine the size of the
 211  * structure. It should be queried before using additional fields added
 212  * at the end of the structure.
 213  */
 214
 215 struct lttng_ust_enum_desc {
 216         uint32_t struct_size;
 217
 218         const char *name;
 219         const struct lttng_ust_enum_entry **entries;
 220         unsigned int nr_entries;
 221
 222         /* End of base ABI. Fields below should be used after checking struct_size. */
 223 };
 224
 225 /*
 226  * Event field description
 227  *
 228  * IMPORTANT: this structure is part of the ABI between the probe and
 229  * UST. Fields need to be only added at the end, never reordered, never
 230  * removed.
 231  *
 232  * The field @struct_size should be used to determine the size of the
 233  * structure. It should be queried before using additional fields added
 234  * at the end of the structure.
 235  */
 236
 237 struct lttng_ust_event_field {
 238         uint32_t struct_size;
 239
 240         const char *name;
 241         const struct lttng_ust_type_common *type;
 242         unsigned int nowrite:1,         /* do not write into trace */
 243                 nofilter:1;             /* do not consider for filter */
 244
 245         /* End of base ABI. Fields below should be used after checking struct_size. */
 246 };
 247
 248
 249 /*
 250  * IMPORTANT: this structure is part of the ABI between the probe and
 251  * UST. Fields need to be only added at the end, never reordered, never
 252  * removed.
 253  *
 254  * The field @struct_size should be used to determine the size of the
 255  * structure. It should be queried before using additional fields added
 256  * at the end of the structure.
 257  */
 258 struct lttng_ust_event_desc {
 259         uint32_t struct_size;                           /* Size of this structure. */
 260
 261         const char *event_name;
 262         const struct lttng_ust_probe_desc *probe_desc;
 263         void (*probe_callback)(void);
 264         const struct lttng_ust_event_field **fields;    /* event payload */
 265         unsigned int nr_fields;
 266         const int **loglevel;
 267         const char *signature;                          /* Argument types/names received */
 268         const char **model_emf_uri;
 269
 270         /* End of base ABI. Fields below should be used after checking struct_size. */
 271 };
 272
 273 /*
 274  * IMPORTANT: this structure is part of the ABI between the probe and
 275  * UST. Fields need to be only added at the end, never reordered, never
 276  * removed.
 277  *
 278  * The field @struct_size should be used to determine the size of the
 279  * structure. It should be queried before using additional fields added
 280  * at the end of the structure.
 281  */
 282 struct lttng_ust_probe_desc {
 283         uint32_t struct_size;                   /* Size of this structure. */
 284
 285         const char *provider_name;
 286         const struct lttng_ust_event_desc **event_desc;
 287         unsigned int nr_events;
 288         uint32_t major;
 289         uint32_t minor;
 290
 291         /* End of base ABI. Fields below should be used after checking struct_size. */
 292 };
 293
 294 /* Data structures used by the tracer. */
 295
 296 /*
 297  * lttng_event structure is referred to by the tracing fast path. It
 298  * must be kept small.
 299  *
 300  * IMPORTANT: this structure is part of the ABI between the probe and
 301  * UST. Fields need to be only added at the end, never reordered, never
 302  * removed.
 303  */
 304
 305 struct lttng_ust_event_common_private;
 306
 307 enum lttng_ust_event_type {
 308         LTTNG_UST_EVENT_TYPE_RECORDER = 0,
 309         LTTNG_UST_EVENT_TYPE_NOTIFIER = 1,
 310 };
 311
 312 /*
 313  * Result of the run_filter() callback.
 314  */
 315 enum lttng_ust_event_filter_result {
 316         LTTNG_UST_EVENT_FILTER_ACCEPT = 0,
 317         LTTNG_UST_EVENT_FILTER_REJECT = 1,
 318 };
 319
 320 /*
 321  * IMPORTANT: this structure is part of the ABI between the probe and
 322  * UST. Fields need to be only added at the end, never reordered, never
 323  * removed.
 324  *
 325  * struct lttng_ust_event_common is the common ancestor of the various
 326  * public event actions. Inheritance is done by composition: The parent
 327  * has a pointer to its child, and the child has a pointer to its
 328  * parent. Inheritance of those public structures is done by composition
 329  * to ensure both parent and child structures can be extended.
 330  *
 331  * The field @struct_size should be used to determine the size of the
 332  * structure. It should be queried before using additional fields added
 333  * at the end of the structure.
 334  */
 335 struct lttng_ust_event_common {
 336         uint32_t struct_size;                           /* Size of this structure. */
 337
 338         struct lttng_ust_event_common_private *priv;    /* Private event interface */
 339
 340         enum lttng_ust_event_type type;
 341         void *child;                                    /* Pointer to child, for inheritance by aggregation. */
 342
 343         int enabled;
 344         int eval_filter;                                /* Need to evaluate filters */
 345         int (*run_filter)(struct lttng_ust_event_common *event,
 346                 const char *stack_data,
 347                 void *filter_ctx);
 348
 349         /* End of base ABI. Fields below should be used after checking struct_size. */
 350 };
 351
 352 struct lttng_ust_event_recorder_private;
 353
 354 /*
 355  * IMPORTANT: this structure is part of the ABI between the probe and
 356  * UST. Fields need to be only added at the end, never reordered, never
 357  * removed.
 358  *
 359  * struct lttng_ust_event_recorder is the action for recording events
 360  * into a ring buffer. It inherits from struct lttng_ust_event_common
 361  * by composition to ensure both parent and child structure are
 362  * extensible.
 363  *
 364  * The field @struct_size should be used to determine the size of the
 365  * structure. It should be queried before using additional fields added
 366  * at the end of the structure.
 367  */
 368 struct lttng_ust_event_recorder {
 369         uint32_t struct_size;                           /* Size of this structure. */
 370
 371         struct lttng_ust_event_common *parent;          /* Inheritance by aggregation. */
 372         struct lttng_ust_event_recorder_private *priv;  /* Private event record interface */
 373
 374         struct lttng_ust_channel_buffer *chan;
 375
 376         /* End of base ABI. Fields below should be used after checking struct_size. */
 377 };
 378
 379 /*
 380  * IMPORTANT: this structure is part of the ABI between the probe and
 381  * UST. Fields need to be only added at the end, never reordered, never
 382  * removed.
 383  *
 384  * The field @struct_size should be used to determine the size of the
 385  * structure. It should be queried before using additional fields added
 386  * at the end of the structure.
 387  */
 388 struct lttng_ust_notification_ctx {
 389         uint32_t struct_size;           /* Size of this structure. */
 390         int eval_capture;               /* Capture evaluation available. */
 391
 392         /* End of base ABI. Fields below should be used after checking struct_size. */
 393 };
 394
 395 struct lttng_ust_event_notifier_private;
 396
 397 /*
 398  * IMPORTANT: this structure is part of the ABI between the probe and
 399  * UST. Fields need to be only added at the end, never reordered, never
 400  * removed.
 401  *
 402  * struct lttng_ust_event_notifier is the action for sending
 403  * notifications. It inherits from struct lttng_ust_event_common
 404  * by composition to ensure both parent and child structure are
 405  * extensible.
 406  *
 407  * The field @struct_size should be used to determine the size of the
 408  * structure. It should be queried before using additional fields added
 409  * at the end of the structure.
 410  */
 411 struct lttng_ust_event_notifier {
 412         uint32_t struct_size;                           /* Size of this structure. */
 413
 414         struct lttng_ust_event_common *parent;          /* Inheritance by aggregation. */
 415         struct lttng_ust_event_notifier_private *priv;  /* Private event notifier interface */
 416
 417         int eval_capture;                               /* Need to evaluate capture */
 418         void (*notification_send)(struct lttng_ust_event_notifier *event_notifier,
 419                 const char *stack_data,
 420                 struct lttng_ust_notification_ctx *notif_ctx);
 421
 422         /* End of base ABI. Fields below should be used after checking struct_size. */
 423 };
 424
 425 struct lttng_ust_lib_ring_buffer_channel;
 426 struct lttng_ust_channel_buffer_ops_private;
 427
 428 /*
 429  * IMPORTANT: this structure is part of the ABI between the probe and
 430  * UST. Fields need to be only added at the end, never reordered, never
 431  * removed.
 432  *
 433  * The field @struct_size should be used to determine the size of the
 434  * structure. It should be queried before using additional fields added
 435  * at the end of the structure.
 436  */
 437 struct lttng_ust_channel_buffer_ops {
 438         uint32_t struct_size;
 439
 440         struct lttng_ust_channel_buffer_ops_private *priv;      /* Private channel buffer ops interface */
 441
 442         int (*event_reserve)(struct lttng_ust_lib_ring_buffer_ctx *ctx);
 443         void (*event_commit)(struct lttng_ust_lib_ring_buffer_ctx *ctx);
 444         void (*event_write)(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 445                         const void *src, size_t len, size_t alignment);
 446         void (*event_strcpy)(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 447                         const char *src, size_t len);
 448         void (*event_pstrcpy_pad)(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 449                         const char *src, size_t len);
 450
 451         /* End of base ABI. Fields below should be used after checking struct_size. */
 452 };
 453
 454 enum lttng_ust_channel_type {
 455         LTTNG_UST_CHANNEL_TYPE_BUFFER = 0,
 456 };
 457
 458 struct lttng_ust_channel_common_private;
 459
 460 /*
 461  * IMPORTANT: this structure is part of the ABI between the probe and
 462  * UST. Fields need to be only added at the end, never reordered, never
 463  * removed.
 464  *
 465  * The field @struct_size should be used to determine the size of the
 466  * structure. It should be queried before using additional fields added
 467  * at the end of the structure.
 468  */
 469 struct lttng_ust_channel_common {
 470         uint32_t struct_size;                           /* Size of this structure. */
 471
 472         struct lttng_ust_channel_common_private *priv;  /* Private channel interface */
 473
 474         enum lttng_ust_channel_type type;
 475         void *child;                                    /* Pointer to child, for inheritance by aggregation. */
 476
 477         int enabled;
 478         struct lttng_ust_session *session;
 479
 480         /* End of base ABI. Fields below should be used after checking struct_size. */
 481 };
 482
 483 struct lttng_ust_channel_buffer_private;
 484
 485 /*
 486  * IMPORTANT: this structure is part of the ABI between the probe and
 487  * UST. Fields need to be only added at the end, never reordered, never
 488  * removed.
 489  *
 490  * The field @struct_size should be used to determine the size of the
 491  * structure. It should be queried before using additional fields added
 492  * at the end of the structure.
 493  */
 494 struct lttng_ust_channel_buffer {
 495         uint32_t struct_size;                           /* Size of this structure. */
 496
 497         struct lttng_ust_channel_common *parent;        /* Inheritance by aggregation. */
 498         struct lttng_ust_channel_buffer_private *priv;  /* Private channel buffer interface */
 499
 500         struct lttng_ust_channel_buffer_ops *ops;
 501
 502         /* End of base ABI. Fields below should be used after checking struct_size. */
 503 };
 504
 505 /*
 506  * IMPORTANT: this structure is part of the ABI between the probe and
 507  * UST. Fields need to be only added at the end, never reordered, never
 508  * removed.
 509  *
 510  * The field @struct_size should be used to determine the size of the
 511  * structure. It should be queried before using additional fields added
 512  * at the end of the structure.
 513  */
 514 struct lttng_ust_stack_ctx {
 515         uint32_t struct_size;                   /* Size of this structure */
 516
 517         struct lttng_ust_event_recorder *event_recorder;
 518
 519         /* End of base ABI. Fields below should be used after checking struct_size. */
 520 };
 521
 522 struct lttng_ust_session_private;
 523
 524 /*
 525  * IMPORTANT: this structure is part of the ABI between the probe and
 526  * UST. Fields need to be only added at the end, never reordered, never
 527  * removed.
 528  *
 529  * The field @struct_size should be used to determine the size of the
 530  * structure. It should be queried before using additional fields added
 531  * at the end of the structure.
 532  */
 533 struct lttng_ust_session {
 534         uint32_t struct_size;                   /* Size of this structure */
 535
 536         struct lttng_ust_session_private *priv; /* Private session interface */
 537
 538         int active;                             /* Is trace session active ? */
 539
 540         /* End of base ABI. Fields below should be used after checking struct_size. */
 541 };
 542
 543 /*
 544  * On successful registration of a probe, a pointer to an opaque
 545  * structure is returned. This pointer should be passed to
 546  * lttng_ust_probe_unregister for unregistration.
 547  * lttng_ust_probe_register returns NULL on error.
 548  */
 549 struct lttng_ust_registered_probe *lttng_ust_probe_register(const struct lttng_ust_probe_desc *desc);
 550
 551 void lttng_ust_probe_unregister(struct lttng_ust_registered_probe *reg_probe);
 552
 553 /*
 554  * Applications that change their procname and need the new value to be
 555  * reflected in the procname event context have to call this function to clear
 556  * the internally cached value. This should not be called from a signal
 557  * handler.
 558  */
 559 void lttng_ust_context_procname_reset(void);
 560
 561 #ifdef __cplusplus
 562 }
 563 #endif
 564
 565 #endif /* _LTTNG_UST_EVENTS_H */