src/bin/lttng-sessiond/field.hpp

   1 /*
   2  * Copyright (C) 2022 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #ifndef LTTNG_FIELD_H
   9 #define LTTNG_FIELD_H
  10
  11 #include <common/format.hpp>
  12 #include <common/make-unique.hpp>
  13
  14 #include <vendor/optional.hpp>
  15
  16 #include <algorithm>
  17 #include <memory>
  18 #include <string>
  19 #include <type_traits>
  20 #include <vector>
  21
  22 namespace lttng {
  23 namespace sessiond {
  24 namespace trace {
  25
  26 class field_visitor;
  27 class type_visitor;
  28
  29 enum class byte_order {
  30         BIG_ENDIAN_,
  31         LITTLE_ENDIAN_,
  32 };
  33
  34 class field_location {
  35 public:
  36         enum class root {
  37                 PACKET_HEADER,
  38                 PACKET_CONTEXT,
  39                 EVENT_RECORD_HEADER,
  40                 EVENT_RECORD_COMMON_CONTEXT,
  41                 EVENT_RECORD_SPECIFIC_CONTEXT,
  42                 EVENT_RECORD_PAYLOAD,
  43         };
  44
  45         using elements = std::vector<std::string>;
  46
  47         field_location(root lookup_root, elements elements);
  48         bool operator==(const field_location& other) const noexcept;
  49
  50         const root root_;
  51         const elements elements_;
  52 };
  53
  54 /*
  55  * Field, and the various field types, represents fields as exposed by the
  56  * LTTng tracers. These classes do not attempt to describe the complete spectrum of the CTF
  57  * specification.
  58  */
  59
  60 class type {
  61 public:
  62         using cuptr = std::unique_ptr<const type>;
  63
  64         static byte_order reverse_byte_order(byte_order byte_order) noexcept;
  65
  66         bool operator==(const type& other) const noexcept;
  67         bool operator!=(const type& other) const noexcept;
  68
  69         virtual ~type();
  70         type(const type&) = delete;
  71         type(type&&) = delete;
  72         type& operator=(type&&) = delete;
  73         type& operator=(const type&) = delete;
  74
  75         /* Obtain an independent copy of `type`. */
  76         virtual type::cuptr copy() const = 0;
  77
  78         virtual void accept(type_visitor& visitor) const = 0;
  79
  80         const unsigned int alignment;
  81
  82 protected:
  83         explicit type(unsigned int alignment);
  84
  85 private:
  86         virtual bool _is_equal(const type& rhs) const noexcept = 0;
  87 };
  88
  89 class field {
  90 public:
  91         using uptr = std::unique_ptr<field>;
  92         using cuptr = std::unique_ptr<const field>;
  93
  94         field(std::string name, type::cuptr type);
  95         void accept(field_visitor& visitor) const;
  96         bool operator==(const field& other) const noexcept;
  97
  98         const type& get_type() const;
  99         type::cuptr move_type() noexcept;
 100
 101         const std::string name;
 102
 103 private:
 104         type::cuptr _type;
 105 };
 106
 107 class integer_type : public type {
 108 public:
 109         enum class signedness {
 110                 SIGNED,
 111                 UNSIGNED,
 112         };
 113
 114         enum class base {
 115                 BINARY = 2,
 116                 OCTAL = 8,
 117                 DECIMAL = 10,
 118                 HEXADECIMAL = 16,
 119         };
 120
 121         enum class role {
 122                 DEFAULT_CLOCK_TIMESTAMP,
 123                 /* Packet header field class specific roles. */
 124                 DATA_STREAM_CLASS_ID,
 125                 DATA_STREAM_ID,
 126                 PACKET_MAGIC_NUMBER,
 127                 /* Packet context field class specific roles. */
 128                 DISCARDED_EVENT_RECORD_COUNTER_SNAPSHOT,
 129                 PACKET_CONTENT_LENGTH,
 130                 PACKET_END_DEFAULT_CLOCK_TIMESTAMP,
 131                 PACKET_SEQUENCE_NUMBER,
 132                 PACKET_TOTAL_LENGTH,
 133                 /* Event record field class roles. */
 134                 EVENT_RECORD_CLASS_ID,
 135         };
 136
 137         using roles = std::vector<role>;
 138
 139         integer_type(unsigned int alignment,
 140                      byte_order byte_order,
 141                      unsigned int size,
 142                      signedness signedness,
 143                      base base,
 144                      roles roles = {});
 145
 146         type::cuptr copy() const override;
 147
 148         void accept(type_visitor& visitor) const override;
 149
 150         const enum byte_order byte_order;
 151         const unsigned int size;
 152         /*
 153          * signedness and base are suffixed with '_' to work-around a bug in older
 154          * GCCs (before 6) that do not recognize hidden/shadowed enumeration as valid
 155          * nested-name-specifiers.
 156          */
 157         const signedness signedness_;
 158         const base base_;
 159         const roles roles_;
 160
 161 protected:
 162         bool _is_equal(const type& other) const noexcept override;
 163 };
 164
 165 class floating_point_type : public type {
 166 public:
 167         floating_point_type(unsigned int alignment,
 168                             byte_order byte_order,
 169                             unsigned int exponent_digits,
 170                             unsigned int mantissa_digits);
 171
 172         type::cuptr copy() const final;
 173
 174         void accept(type_visitor& visitor) const final;
 175
 176         const enum byte_order byte_order;
 177         const unsigned int exponent_digits;
 178         const unsigned int mantissa_digits;
 179
 180 private:
 181         bool _is_equal(const type& other) const noexcept final;
 182 };
 183
 184 class enumeration_type : public integer_type {
 185 public:
 186         ~enumeration_type() override = default;
 187         enumeration_type(const enumeration_type&) = delete;
 188         enumeration_type(enumeration_type&&) = delete;
 189         enumeration_type& operator=(enumeration_type&&) = delete;
 190         enumeration_type& operator=(const enumeration_type&) = delete;
 191
 192 protected:
 193         enumeration_type(unsigned int alignment,
 194                          enum byte_order byte_order,
 195                          unsigned int size,
 196                          enum signedness signedness,
 197                          enum base base,
 198                          integer_type::roles roles = {});
 199
 200         void accept(type_visitor& visitor) const override = 0;
 201 };
 202
 203 namespace details {
 204 template <class MappingIntegerType>
 205 class enumeration_mapping_range {
 206 public:
 207         using range_integer_t = MappingIntegerType;
 208
 209         enumeration_mapping_range(MappingIntegerType in_begin, MappingIntegerType in_end) :
 210                 begin{ in_begin }, end{ in_end }
 211         {
 212         }
 213
 214         const range_integer_t begin, end;
 215 };
 216
 217 template <class MappingIntegerType>
 218 bool operator==(const enumeration_mapping_range<MappingIntegerType>& lhs,
 219                 const enumeration_mapping_range<MappingIntegerType>& rhs) noexcept
 220 {
 221         return lhs.begin == rhs.begin && lhs.end == rhs.end;
 222 }
 223
 224 template <class MappingIntegerType>
 225 class enumeration_mapping {
 226 public:
 227         using range_t = enumeration_mapping_range<MappingIntegerType>;
 228
 229         enumeration_mapping(std::string in_name, MappingIntegerType value) :
 230                 name{ std::move(in_name) }, range{ value, value }
 231         {
 232         }
 233
 234         enumeration_mapping(std::string in_name, range_t in_range) :
 235                 name{ std::move(in_name) }, range{ in_range }
 236         {
 237         }
 238
 239         enumeration_mapping(const enumeration_mapping<MappingIntegerType>& other) = default;
 240         enumeration_mapping(enumeration_mapping<MappingIntegerType>&& other) noexcept :
 241                 name{ std::move(other.name) }, range{ other.range }
 242         {
 243         }
 244
 245         enumeration_mapping& operator=(enumeration_mapping&&) = delete;
 246         enumeration_mapping& operator=(const enumeration_mapping&) = delete;
 247         ~enumeration_mapping() = default;
 248
 249         const std::string name;
 250         /*
 251          * Only one range per mapping is supported for the moment as
 252          * the tracers (and CTF 1.8) can't express multiple ranges per
 253          * mapping, which is allowed by CTF 2.
 254          */
 255         const range_t range;
 256 };
 257
 258 template <class MappingIntegerType>
 259 bool operator==(const enumeration_mapping<MappingIntegerType>& lhs,
 260                 const enumeration_mapping<MappingIntegerType>& rhs) noexcept
 261 {
 262         return lhs.name == rhs.name && lhs.range == rhs.range;
 263 }
 264 } /* namespace details */
 265
 266 template <typename MappingIntegerType>
 267 class typed_enumeration_type : public enumeration_type {
 268 public:
 269         using mapping = details::enumeration_mapping<MappingIntegerType>;
 270         using mappings = std::vector<mapping>;
 271
 272         static_assert(std::is_integral<MappingIntegerType>::value &&
 273                               sizeof(MappingIntegerType) == 8,
 274                       "MappingIntegerType must be either int64_t or uint64_t");
 275
 276         typed_enumeration_type(unsigned int in_alignment,
 277                                enum byte_order in_byte_order,
 278                                unsigned int in_size,
 279                                enum base in_base,
 280                                const std::shared_ptr<const mappings>& in_mappings,
 281                                integer_type::roles in_roles = {}) :
 282                 enumeration_type(in_alignment,
 283                                  in_byte_order,
 284                                  in_size,
 285                                  std::is_signed<MappingIntegerType>::value ?
 286                                          integer_type::signedness::SIGNED :
 287                                          integer_type::signedness::UNSIGNED,
 288                                  in_base,
 289                                  std::move(in_roles)),
 290                 mappings_{ std::move(in_mappings) }
 291         {
 292         }
 293
 294         type::cuptr copy() const override
 295         {
 296                 return lttng::make_unique<typed_enumeration_type<MappingIntegerType>>(
 297                         alignment, byte_order, size, base_, mappings_, roles_);
 298         }
 299
 300         void accept(type_visitor& visitor) const final;
 301
 302         const std::shared_ptr<const mappings> mappings_;
 303
 304 private:
 305         bool _is_equal(const type& base_other) const noexcept final
 306         {
 307                 const auto& other =
 308                         static_cast<const typed_enumeration_type<MappingIntegerType>&>(base_other);
 309
 310                 return integer_type::_is_equal(base_other) && *this->mappings_ == *other.mappings_;
 311         }
 312 };
 313
 314 /* Aliases for all allowed enumeration mapping types. */
 315 using signed_enumeration_type = typed_enumeration_type<int64_t>;
 316 using unsigned_enumeration_type = typed_enumeration_type<uint64_t>;
 317
 318 class array_type : public type {
 319 public:
 320         array_type(unsigned int alignment, type::cuptr element_type);
 321
 322         const type::cuptr element_type;
 323
 324 protected:
 325         bool _is_equal(const type& base_other) const noexcept override;
 326 };
 327
 328 class static_length_array_type : public array_type {
 329 public:
 330         static_length_array_type(unsigned int alignment,
 331                                  type::cuptr element_type,
 332                                  uint64_t in_length);
 333
 334         type::cuptr copy() const final;
 335
 336         void accept(type_visitor& visitor) const final;
 337
 338         const uint64_t length;
 339
 340 private:
 341         bool _is_equal(const type& base_other) const noexcept final;
 342 };
 343
 344 class dynamic_length_array_type : public array_type {
 345 public:
 346         dynamic_length_array_type(unsigned int alignment,
 347                                   type::cuptr element_type,
 348                                   field_location length_field_location);
 349
 350         type::cuptr copy() const final;
 351
 352         void accept(type_visitor& visitor) const final;
 353
 354         const field_location length_field_location;
 355
 356 private:
 357         bool _is_equal(const type& base_other) const noexcept final;
 358 };
 359
 360 class static_length_blob_type : public type {
 361 public:
 362         enum class role {
 363                 /* Packet header field class specific role. */
 364                 METADATA_STREAM_UUID,
 365         };
 366
 367         using roles = std::vector<role>;
 368
 369         static_length_blob_type(unsigned int alignment, uint64_t in_length_bytes, roles roles = {});
 370
 371         type::cuptr copy() const final;
 372
 373         void accept(type_visitor& visitor) const final;
 374
 375         const uint64_t length_bytes;
 376         const roles roles_;
 377
 378 private:
 379         bool _is_equal(const type& base_other) const noexcept final;
 380 };
 381
 382 class dynamic_length_blob_type : public type {
 383 public:
 384         dynamic_length_blob_type(unsigned int alignment, field_location length_field_location);
 385
 386         type::cuptr copy() const final;
 387
 388         void accept(type_visitor& visitor) const final;
 389
 390         const field_location length_field_location;
 391
 392 private:
 393         bool _is_equal(const type& base_other) const noexcept final;
 394 };
 395
 396 class string_type : public type {
 397 public:
 398         enum class encoding {
 399                 ASCII,
 400                 UTF8,
 401         };
 402
 403         string_type(unsigned int alignment, enum encoding encoding);
 404
 405         /*
 406          * encoding is suffixed with '_' to work-around a bug in older
 407          * GCCs (before 6) that do not recognize hidden/shadowed enumeration as valid
 408          * nested-name-specifiers.
 409          */
 410         const encoding encoding_;
 411
 412 protected:
 413         bool _is_equal(const type& base_other) const noexcept override;
 414 };
 415
 416 class static_length_string_type : public string_type {
 417 public:
 418         static_length_string_type(unsigned int alignment,
 419                                   enum encoding in_encoding,
 420                                   uint64_t length);
 421
 422         type::cuptr copy() const final;
 423
 424         void accept(type_visitor& visitor) const final;
 425
 426         const uint64_t length;
 427
 428 private:
 429         bool _is_equal(const type& base_other) const noexcept final;
 430 };
 431
 432 class dynamic_length_string_type : public string_type {
 433 public:
 434         dynamic_length_string_type(unsigned int alignment,
 435                                    enum encoding in_encoding,
 436                                    field_location length_field_location);
 437
 438         type::cuptr copy() const final;
 439
 440         void accept(type_visitor& visitor) const final;
 441
 442         const field_location length_field_location;
 443
 444 private:
 445         bool _is_equal(const type& base_other) const noexcept final;
 446 };
 447
 448 class null_terminated_string_type : public string_type {
 449 public:
 450         null_terminated_string_type(unsigned int alignment, enum encoding in_encoding);
 451
 452         type::cuptr copy() const final;
 453
 454         void accept(type_visitor& visitor) const final;
 455 };
 456
 457 class structure_type : public type {
 458 public:
 459         using fields = std::vector<field::cuptr>;
 460
 461         structure_type(unsigned int alignment, fields in_fields);
 462
 463         type::cuptr copy() const final;
 464
 465         void accept(type_visitor& visitor) const final;
 466
 467         const fields fields_;
 468
 469 private:
 470         bool _is_equal(const type& base_other) const noexcept final;
 471 };
 472
 473 template <typename MappingIntegerType>
 474 class variant_type : public type {
 475         static_assert(
 476                 std::is_same<MappingIntegerType,
 477                              unsigned_enumeration_type::mapping::range_t::range_integer_t>::value ||
 478                         std::is_same<
 479                                 MappingIntegerType,
 480                                 signed_enumeration_type::mapping::range_t::range_integer_t>::value,
 481                 "Variant mapping integer type must be one of those allowed by typed_enumeration_type");
 482
 483 public:
 484         using choice =
 485                 std::pair<const details::enumeration_mapping<MappingIntegerType>, type::cuptr>;
 486         using choices = std::vector<choice>;
 487
 488         variant_type(unsigned int in_alignment,
 489                      field_location in_selector_field_location,
 490                      choices in_choices) :
 491                 type(in_alignment),
 492                 selector_field_location{ std::move(in_selector_field_location) },
 493                 choices_{ std::move(in_choices) }
 494         {
 495         }
 496
 497         type::cuptr copy() const final
 498         {
 499                 choices copy_of_choices;
 500
 501                 copy_of_choices.reserve(choices_.size());
 502                 for (const auto& current_choice : choices_) {
 503                         copy_of_choices.emplace_back(current_choice.first,
 504                                                      current_choice.second->copy());
 505                 }
 506
 507                 return lttng::make_unique<variant_type<MappingIntegerType>>(
 508                         alignment, selector_field_location, std::move(copy_of_choices));
 509         }
 510
 511         void accept(type_visitor& visitor) const final;
 512
 513         const field_location selector_field_location;
 514         const choices choices_;
 515
 516 private:
 517         static bool _choices_are_equal(const choices& a, const choices& b)
 518         {
 519                 if (a.size() != b.size()) {
 520                         return false;
 521                 }
 522
 523                 return std::equal(a.cbegin(),
 524                                   a.cend(),
 525                                   b.cbegin(),
 526                                   [](const choice& choice_a, const choice& choice_b) {
 527                                           return choice_a.first == choice_b.first &&
 528                                                   *choice_a.second == *choice_b.second;
 529                                   });
 530         }
 531
 532         bool _is_equal(const type& base_other) const noexcept final
 533         {
 534                 const auto& other = static_cast<decltype(*this)&>(base_other);
 535
 536                 return selector_field_location == other.selector_field_location &&
 537                         _choices_are_equal(choices_, other.choices_);
 538         }
 539 };
 540
 541 class field_visitor {
 542 public:
 543         virtual ~field_visitor() = default;
 544         field_visitor(field_visitor&&) = delete;
 545         field_visitor(const field_visitor&) = delete;
 546         field_visitor& operator=(const field_visitor&) = delete;
 547         field_visitor& operator=(field_visitor&&) = delete;
 548
 549         virtual void visit(const field& field) = 0;
 550
 551 protected:
 552         field_visitor() = default;
 553 };
 554
 555 class type_visitor {
 556 public:
 557         virtual ~type_visitor() = default;
 558         type_visitor(type_visitor&&) = delete;
 559         type_visitor(const type_visitor&) = delete;
 560         type_visitor& operator=(const type_visitor&) = delete;
 561         type_visitor& operator=(type_visitor&&) = delete;
 562
 563         virtual void visit(const integer_type& type) = 0;
 564         virtual void visit(const floating_point_type& type) = 0;
 565         virtual void visit(const signed_enumeration_type& type) = 0;
 566         virtual void visit(const unsigned_enumeration_type& type) = 0;
 567         virtual void visit(const static_length_array_type& type) = 0;
 568         virtual void visit(const dynamic_length_array_type& type) = 0;
 569         virtual void visit(const static_length_blob_type& type) = 0;
 570         virtual void visit(const dynamic_length_blob_type& type) = 0;
 571         virtual void visit(const null_terminated_string_type& type) = 0;
 572         virtual void visit(const static_length_string_type& type) = 0;
 573         virtual void visit(const dynamic_length_string_type& type) = 0;
 574         virtual void visit(const structure_type& type) = 0;
 575         virtual void
 576         visit(const variant_type<signed_enumeration_type::mapping::range_t::range_integer_t>&
 577                       type) = 0;
 578         virtual void
 579         visit(const variant_type<unsigned_enumeration_type::mapping::range_t::range_integer_t>&
 580                       type) = 0;
 581
 582 protected:
 583         type_visitor() = default;
 584 };
 585
 586 } /* namespace trace */
 587 } /* namespace sessiond */
 588 } /* namespace lttng */
 589
 590 /*
 591  * Field formatters for libfmt.
 592  *
 593  * Due to a bug in g++ < 7.1, this specialization must be enclosed in the fmt namespace,
 594  * see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56480.
 595  */
 596 namespace fmt {
 597 template <>
 598 struct formatter<lttng::sessiond::trace::field_location> : formatter<std::string> {
 599         template <typename FormatContextType>
 600         typename FormatContextType::iterator
 601         format(const lttng::sessiond::trace::field_location& location, FormatContextType& ctx)
 602         {
 603                 std::string location_str{ "[" };
 604
 605                 switch (location.root_) {
 606                 case lttng::sessiond::trace::field_location::root::PACKET_HEADER:
 607                         location_str += "\"packet-header\"";
 608                         break;
 609                 case lttng::sessiond::trace::field_location::root::PACKET_CONTEXT:
 610                         location_str += "\"packet-context\"";
 611                         break;
 612                 case lttng::sessiond::trace::field_location::root::EVENT_RECORD_HEADER:
 613                         location_str += "\"event-record-header\"";
 614                         break;
 615                 case lttng::sessiond::trace::field_location::root::EVENT_RECORD_COMMON_CONTEXT:
 616                         location_str += "\"event-record-common-context\"";
 617                         break;
 618                 case lttng::sessiond::trace::field_location::root::EVENT_RECORD_SPECIFIC_CONTEXT:
 619                         location_str += "\"event-record-specific-context\"";
 620                         break;
 621                 case lttng::sessiond::trace::field_location::root::EVENT_RECORD_PAYLOAD:
 622                         location_str += "\"event-record-payload\"";
 623                         break;
 624                 }
 625
 626                 for (const auto& name : location.elements_) {
 627                         location_str += ", \"" + name + "\"";
 628                 }
 629
 630                 location_str += "]";
 631                 return format_to(ctx.out(), location_str);
 632         }
 633 };
 634
 635 namespace details {
 636 template <typename MappingIntegerType>
 637 ::std::string format_mapping_range(typename lttng::sessiond::trace::typed_enumeration_type<
 638                                    MappingIntegerType>::mapping::range_t range)
 639 {
 640         if (range.begin == range.end) {
 641                 return ::lttng::format("[{}]", range.begin);
 642         } else {
 643                 return ::lttng::format("[{}, {}]", range.begin, range.end);
 644         }
 645 }
 646 } /* namespace details */
 647
 648 template <>
 649 struct formatter<typename lttng::sessiond::trace::signed_enumeration_type::mapping::range_t>
 650         : formatter<std::string> {
 651         template <typename FormatContextType>
 652         typename FormatContextType::iterator
 653         format(typename lttng::sessiond::trace::signed_enumeration_type::mapping::range_t range,
 654                FormatContextType& ctx)
 655         {
 656                 return format_to(ctx.out(),
 657                                  details::format_mapping_range<
 658                                          lttng::sessiond::trace::signed_enumeration_type::mapping::
 659                                                  range_t::range_integer_t>(range));
 660         }
 661 };
 662
 663 template <>
 664 struct formatter<typename lttng::sessiond::trace::unsigned_enumeration_type::mapping::range_t>
 665         : formatter<std::string> {
 666         template <typename FormatContextType>
 667         typename FormatContextType::iterator
 668         format(typename lttng::sessiond::trace::unsigned_enumeration_type::mapping::range_t range,
 669                FormatContextType& ctx)
 670         {
 671                 return format_to(ctx.out(),
 672                                  details::format_mapping_range<
 673                                          lttng::sessiond::trace::unsigned_enumeration_type::
 674                                                  mapping::range_t::range_integer_t>(range));
 675         }
 676 };
 677
 678 } /* namespace fmt */
 679
 680 #endif /* LTTNG_FIELD_H */