Document public event and session structures
[lttng-ust.git] / 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 #define LTTNG_UST_EVENT_DESC_PADDING 40
278 struct lttng_event_desc {
279 const char *name;
280 void (*probe_callback)(void);
281 const struct lttng_event_ctx *ctx; /* context */
282 const struct lttng_event_field *fields; /* event payload */
283 unsigned int nr_fields;
284 const int **loglevel;
285 const char *signature; /* Argument types/names received */
286 union {
287 struct {
288 const char **model_emf_uri;
289 } ext;
290 char padding[LTTNG_UST_EVENT_DESC_PADDING];
291 } u;
292 };
293
294 #define LTTNG_UST_PROBE_DESC_PADDING 12
295 struct lttng_probe_desc {
296 const char *provider;
297 const struct lttng_event_desc **event_desc;
298 unsigned int nr_events;
299 struct cds_list_head head; /* chain registered probes */
300 struct cds_list_head lazy_init_head;
301 int lazy; /* lazy registration */
302 uint32_t major;
303 uint32_t minor;
304 char padding[LTTNG_UST_PROBE_DESC_PADDING];
305 };
306
307 /* Data structures used by the tracer. */
308
309 /*
310 * Bytecode interpreter return value masks.
311 */
312 enum lttng_bytecode_interpreter_ret {
313 LTTNG_INTERPRETER_DISCARD = 0,
314 LTTNG_INTERPRETER_RECORD_FLAG = (1ULL << 0),
315 /* Other bits are kept for future use. */
316 };
317
318 struct lttng_interpreter_output;
319 struct lttng_ust_bytecode_runtime_private;
320
321 /*
322 * This structure is used in the probes. More specifically, the
323 * `interpreter_funcs` and `node` fields are explicity used in the
324 * probes. When modifying this structure we must not change the layout
325 * of these two fields as it is considered ABI.
326 */
327 struct lttng_bytecode_runtime {
328 struct lttng_ust_bytecode_runtime_private *priv;
329
330 /* Associated bytecode */
331 union {
332 uint64_t (*filter)(void *interpreter_data,
333 const char *interpreter_stack_data);
334 uint64_t (*capture)(void *interpreter_data,
335 const char *interpreter_stack_data,
336 struct lttng_interpreter_output *interpreter_output);
337 } interpreter_funcs;
338 struct cds_list_head node; /* list of bytecode runtime in event */
339 };
340
341 /*
342 * lttng_event structure is referred to by the tracing fast path. It
343 * must be kept small.
344 *
345 * IMPORTANT: this structure is part of the ABI between the probe and
346 * UST. Fields need to be only added at the end, never reordered, never
347 * removed.
348 */
349
350 struct lttng_ust_event_common_private;
351
352 enum lttng_ust_event_type {
353 LTTNG_UST_EVENT_TYPE_RECORDER = 0,
354 LTTNG_UST_EVENT_TYPE_NOTIFIER = 1,
355 };
356
357 /*
358 * IMPORTANT: this structure is part of the ABI between the probe and
359 * UST. Fields need to be only added at the end, never reordered, never
360 * removed.
361 *
362 * struct lttng_ust_event_common is the common ancestor of the various
363 * public event actions. Inheritance is done by composition: The parent
364 * has a pointer to its child, and the child has a pointer to its
365 * parent. Inheritance of those public structures is done by composition
366 * to ensure both parent and child structures can be extended.
367 *
368 * The field @struct_size should be used to determine the size of the
369 * structure. It should be queried before using additional fields added
370 * at the end of the structure.
371 */
372 struct lttng_ust_event_common {
373 uint32_t struct_size; /* Size of this structure. */
374 struct lttng_ust_event_common_private *priv; /* Private event interface */
375
376 enum lttng_ust_event_type type;
377 void *child; /* Pointer to child, for inheritance by aggregation. */
378
379 int enabled;
380 int has_enablers_without_bytecode;
381 /* list of struct lttng_bytecode_runtime, sorted by seqnum */
382 struct cds_list_head filter_bytecode_runtime_head;
383
384 /* End of base ABI. Fields below should be used after checking struct_size. */
385 };
386
387 struct lttng_ust_event_recorder_private;
388
389 /*
390 * IMPORTANT: this structure is part of the ABI between the probe and
391 * UST. Fields need to be only added at the end, never reordered, never
392 * removed.
393 *
394 * struct lttng_ust_event_recorder is the action for recording events
395 * into a ring buffer. It inherits from struct lttng_ust_event_common
396 * by composition to ensure both parent and child structure are
397 * extensible.
398 *
399 * The field @struct_size should be used to determine the size of the
400 * structure. It should be queried before using additional fields added
401 * at the end of the structure.
402 */
403 struct lttng_ust_event_recorder {
404 uint32_t struct_size; /* Size of this structure. */
405 struct lttng_ust_event_common *parent; /* Inheritance by aggregation. */
406 struct lttng_ust_event_recorder_private *priv; /* Private event record interface */
407
408 unsigned int id;
409 struct lttng_channel *chan;
410 struct lttng_ctx *ctx;
411
412 /* End of base ABI. Fields below should be used after checking struct_size. */
413 };
414
415 struct lttng_ust_event_notifier_private;
416
417 /*
418 * IMPORTANT: this structure is part of the ABI between the probe and
419 * UST. Fields need to be only added at the end, never reordered, never
420 * removed.
421 *
422 * struct lttng_ust_event_notifier is the action for sending
423 * notifications. It inherits from struct lttng_ust_event_common
424 * by composition to ensure both parent and child structure are
425 * extensible.
426 *
427 * The field @struct_size should be used to determine the size of the
428 * structure. It should be queried before using additional fields added
429 * at the end of the structure.
430 */
431 struct lttng_ust_event_notifier {
432 uint32_t struct_size; /* Size of this structure. */
433 struct lttng_ust_event_common *parent; /* Inheritance by aggregation. */
434 struct lttng_ust_event_notifier_private *priv; /* Private event notifier interface */
435
436 void (*notification_send)(struct lttng_ust_event_notifier *event_notifier,
437 const char *stack_data);
438 struct cds_list_head capture_bytecode_runtime_head;
439
440 /* End of base ABI. Fields below should be used after checking struct_size. */
441 };
442
443 struct lttng_enum {
444 const struct lttng_enum_desc *desc;
445 struct lttng_session *session;
446 struct cds_list_head node; /* Enum list in session */
447 struct cds_hlist_node hlist; /* Session ht of enums */
448 uint64_t id; /* Enumeration ID in sessiond */
449 };
450
451 struct channel;
452 struct lttng_ust_shm_handle;
453
454 /*
455 * IMPORTANT: this structure is part of the ABI between the probe and
456 * UST. Fields need to be only added at the end, never reordered, never
457 * removed.
458 */
459 struct lttng_channel_ops {
460 struct lttng_channel *(*channel_create)(const char *name,
461 void *buf_addr,
462 size_t subbuf_size, size_t num_subbuf,
463 unsigned int switch_timer_interval,
464 unsigned int read_timer_interval,
465 unsigned char *uuid,
466 uint32_t chan_id,
467 const int *stream_fds, int nr_stream_fds,
468 int64_t blocking_timeout);
469 void (*channel_destroy)(struct lttng_channel *chan);
470 int (*event_reserve)(struct lttng_ust_lib_ring_buffer_ctx *ctx,
471 uint32_t event_id);
472 void (*event_commit)(struct lttng_ust_lib_ring_buffer_ctx *ctx);
473 void (*event_write)(struct lttng_ust_lib_ring_buffer_ctx *ctx,
474 const void *src, size_t len);
475 /*
476 * packet_avail_size returns the available size in the current
477 * packet. Note that the size returned is only a hint, since it
478 * may change due to concurrent writes.
479 */
480 size_t (*packet_avail_size)(struct channel *chan,
481 struct lttng_ust_shm_handle *handle);
482 int (*is_finalized)(struct channel *chan);
483 int (*is_disabled)(struct channel *chan);
484 int (*flush_buffer)(struct channel *chan, struct lttng_ust_shm_handle *handle);
485 void (*event_strcpy)(struct lttng_ust_lib_ring_buffer_ctx *ctx,
486 const char *src, size_t len);
487 };
488
489 /*
490 * IMPORTANT: this structure is part of the ABI between the probe and
491 * UST. Fields need to be only added at the end, never reordered, never
492 * removed.
493 */
494 struct lttng_channel {
495 /*
496 * The pointers located in this private data are NOT safe to be
497 * dereferenced by the consumer. The only operations the
498 * consumer process is designed to be allowed to do is to read
499 * and perform subbuffer flush.
500 */
501 struct channel *chan; /* Channel buffers */
502 int enabled;
503 struct lttng_ctx *ctx;
504 /* Event ID management */
505 struct lttng_session *session;
506 int objd; /* Object associated to channel */
507 struct cds_list_head node; /* Channel list in session */
508 const struct lttng_channel_ops *ops;
509 int header_type; /* 0: unset, 1: compact, 2: large */
510 struct lttng_ust_shm_handle *handle; /* shared-memory handle */
511
512 /* Channel ID */
513 unsigned int id;
514 enum lttng_ust_abi_chan_type type;
515 unsigned char uuid[LTTNG_UST_UUID_LEN]; /* Trace session unique ID */
516 int tstate:1; /* Transient enable state */
517 };
518
519 struct lttng_counter_dimension;
520
521 struct lttng_counter_ops {
522 struct lib_counter *(*counter_create)(size_t nr_dimensions,
523 const struct lttng_counter_dimension *dimensions,
524 int64_t global_sum_step,
525 int global_counter_fd,
526 int nr_counter_cpu_fds,
527 const int *counter_cpu_fds,
528 bool is_daemon);
529 void (*counter_destroy)(struct lib_counter *counter);
530 int (*counter_add)(struct lib_counter *counter,
531 const size_t *dimension_indexes, int64_t v);
532 int (*counter_read)(struct lib_counter *counter,
533 const size_t *dimension_indexes, int cpu,
534 int64_t *value, bool *overflow, bool *underflow);
535 int (*counter_aggregate)(struct lib_counter *counter,
536 const size_t *dimension_indexes, int64_t *value,
537 bool *overflow, bool *underflow);
538 int (*counter_clear)(struct lib_counter *counter, const size_t *dimension_indexes);
539 };
540
541 #define LTTNG_UST_STACK_CTX_PADDING 32
542 struct lttng_stack_ctx {
543 struct lttng_ust_event_recorder *event_recorder;
544 struct lttng_ctx *chan_ctx; /* RCU dereferenced. */
545 struct lttng_ctx *event_ctx; /* RCU dereferenced. */
546 char padding[LTTNG_UST_STACK_CTX_PADDING];
547 };
548
549 #define LTTNG_UST_EVENT_HT_BITS 12
550 #define LTTNG_UST_EVENT_HT_SIZE (1U << LTTNG_UST_EVENT_HT_BITS)
551
552 struct lttng_ust_event_ht {
553 struct cds_hlist_head table[LTTNG_UST_EVENT_HT_SIZE];
554 };
555
556 #define LTTNG_UST_EVENT_NOTIFIER_HT_BITS 12
557 #define LTTNG_UST_EVENT_NOTIFIER_HT_SIZE (1U << LTTNG_UST_EVENT_NOTIFIER_HT_BITS)
558 struct lttng_ust_event_notifier_ht {
559 struct cds_hlist_head table[LTTNG_UST_EVENT_NOTIFIER_HT_SIZE];
560 };
561
562 #define LTTNG_UST_ENUM_HT_BITS 12
563 #define LTTNG_UST_ENUM_HT_SIZE (1U << LTTNG_UST_ENUM_HT_BITS)
564
565 struct lttng_ust_enum_ht {
566 struct cds_hlist_head table[LTTNG_UST_ENUM_HT_SIZE];
567 };
568
569 struct lttng_ust_session_private;
570
571 /*
572 * IMPORTANT: this structure is part of the ABI between the probe and
573 * UST. Fields need to be only added at the end, never reordered, never
574 * removed.
575 *
576 * The field @struct_size should be used to determine the size of the
577 * structure. It should be queried before using additional fields added
578 * at the end of the structure.
579 */
580 struct lttng_session {
581 uint32_t struct_size; /* Size of this structure */
582 struct lttng_ust_session_private *priv; /* Private session interface */
583
584 int active; /* Is trace session active ? */
585
586 /* End of base ABI. Fields below should be used after checking struct_size. */
587 };
588
589 int lttng_probe_register(struct lttng_probe_desc *desc);
590 void lttng_probe_unregister(struct lttng_probe_desc *desc);
591
592 /*
593 * Can be used by applications that change their procname to clear the ust cached value.
594 */
595 void lttng_context_procname_reset(void);
596
597 struct lttng_transport *lttng_transport_find(const char *name);
598
599 int lttng_session_active(void);
600
601 void lttng_ust_dl_update(void *ip);
602
603 #ifdef __cplusplus
604 }
605 #endif
606
607 #endif /* _LTTNG_UST_EVENTS_H */
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