src/bin/lttng-sessiond/ust-field-convert.cpp

   1 /*
   2  * Copyright (C) 2022 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #include "ust-field-convert.hpp"
   9
  10 #include <common/exception.hpp>
  11 #include <common/make-unique.hpp>
  12
  13 #include <unordered_map>
  14
  15 namespace lst = lttng::sessiond::trace;
  16 namespace lsu = lttng::sessiond::ust;
  17 namespace {
  18
  19 /*
  20  * Type enclosing the session information that may be required during the decoding
  21  * of the lttng_ust_ctl_field array provided by applications on registration of
  22  * an event.
  23  */
  24 class session_attributes {
  25 public:
  26         using registry_enum_getter_fn =
  27                 std::function<lsu::registry_enum::const_rcu_protected_reference(const char *name,
  28                                                                                 uint64_t id)>;
  29
  30         session_attributes(registry_enum_getter_fn reg_enum_getter,
  31                            lst::byte_order native_trace_byte_order) :
  32                 get_registry_enum{ reg_enum_getter },
  33                 _native_trace_byte_order{ native_trace_byte_order }
  34         {
  35         }
  36
  37         const registry_enum_getter_fn get_registry_enum;
  38         const lst::byte_order _native_trace_byte_order;
  39 };
  40
  41 /* Used to publish fields on which a field being decoded has an implicit dependency. */
  42 using publish_field_fn = std::function<void(lst::field::uptr)>;
  43
  44 /* Look-up field from a field location. */
  45 using lookup_field_fn = std::function<const lst::field&(const lst::field_location&)>;
  46
  47 lst::type::cuptr
  48 create_type_from_ust_ctl_fields(const lttng_ust_ctl_field *current,
  49                                 const lttng_ust_ctl_field *end,
  50                                 const session_attributes& session_attributes,
  51                                 const lttng_ust_ctl_field **next_ust_ctl_field,
  52                                 publish_field_fn publish_field,
  53                                 lookup_field_fn lookup_field,
  54                                 lst::field_location::root lookup_root,
  55                                 lst::field_location::elements& current_field_location_elements,
  56                                 lsu::ctl_field_quirks quirks);
  57
  58 void create_field_from_ust_ctl_fields(const lttng_ust_ctl_field *current,
  59                                       const lttng_ust_ctl_field *end,
  60                                       const session_attributes& session_attributes,
  61                                       const lttng_ust_ctl_field **next_ust_ctl_field,
  62                                       publish_field_fn publish_field,
  63                                       lookup_field_fn lookup_field,
  64                                       lst::field_location::root lookup_root,
  65                                       lst::field_location::elements& current_field_location_elements,
  66                                       lsu::ctl_field_quirks quirks);
  67
  68 template <class UstCtlEncodingType>
  69 enum lst::null_terminated_string_type::encoding
  70 ust_ctl_encoding_to_string_field_encoding(UstCtlEncodingType encoding)
  71 {
  72         static const std::unordered_map<UstCtlEncodingType,
  73                                         enum lst::null_terminated_string_type::encoding>
  74                 encoding_conversion_map = {
  75                         { (UstCtlEncodingType) lttng_ust_ctl_encode_ASCII,
  76                           lst::null_terminated_string_type::encoding::ASCII },
  77                         { (UstCtlEncodingType) lttng_ust_ctl_encode_UTF8,
  78                           lst::null_terminated_string_type::encoding::UTF8 },
  79                 };
  80
  81         const auto encoding_it = encoding_conversion_map.find(encoding);
  82         if (encoding_it == encoding_conversion_map.end()) {
  83                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
  84                         "Unknown lttng_ust_ctl_string_encodings value `{}` encountered when decoding integer field",
  85                         encoding));
  86         }
  87
  88         return encoding_it->second;
  89 }
  90
  91 template <class UstCtlBaseType>
  92 enum lst::integer_type::base ust_ctl_base_to_integer_field_base(UstCtlBaseType base)
  93 {
  94         static const std::unordered_map<UstCtlBaseType, enum lst::integer_type::base>
  95                 base_conversion_map = { { 2, lst::integer_type::base::BINARY },
  96                                         { 8, lst::integer_type::base::OCTAL },
  97                                         { 10, lst::integer_type::base::DECIMAL },
  98                                         { 16, lst::integer_type::base::HEXADECIMAL } };
  99
 100         const auto base_it = base_conversion_map.find(base);
 101         if (base_it == base_conversion_map.end()) {
 102                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 103                         "Unknown integer base value `{}` encountered when decoding integer field",
 104                         base));
 105         }
 106
 107         return base_it->second;
 108 }
 109
 110 lst::type::cuptr
 111 create_integer_type_from_ust_ctl_fields(const lttng_ust_ctl_field *current,
 112                                         const lttng_ust_ctl_field *end,
 113                                         const session_attributes& session_attributes,
 114                                         const lttng_ust_ctl_field **next_ust_ctl_field,
 115                                         lsu::ctl_field_quirks quirks __attribute__((unused)))
 116 {
 117         if (current >= end) {
 118                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 119                         "End of {} array reached unexpectedly during decoding", typeid(*current)));
 120         }
 121
 122         const auto base = ust_ctl_base_to_integer_field_base(current->type.u.integer.base);
 123         const auto signedness = current->type.u.integer.signedness ?
 124                 lst::integer_type::signedness::SIGNED :
 125                 lst::integer_type::signedness::UNSIGNED;
 126         const auto byte_order = current->type.u.integer.reverse_byte_order ?
 127                 lst::type::reverse_byte_order(session_attributes._native_trace_byte_order) :
 128                 session_attributes._native_trace_byte_order;
 129
 130         *next_ust_ctl_field = current + 1;
 131
 132         return lttng::make_unique<const lst::integer_type>(current->type.u.integer.alignment,
 133                                                            byte_order,
 134                                                            current->type.u.integer.size,
 135                                                            signedness,
 136                                                            base);
 137 }
 138
 139 lst::type::cuptr
 140 create_floating_point_type_from_ust_ctl_fields(const lttng_ust_ctl_field *current,
 141                                                const lttng_ust_ctl_field *end,
 142                                                const session_attributes& session_attributes,
 143                                                const lttng_ust_ctl_field **next_ust_ctl_field,
 144                                                lsu::ctl_field_quirks quirks __attribute__((unused)))
 145 {
 146         if (current >= end) {
 147                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 148                         "End of {} array reached unexpectedly during decoding", typeid(*current)));
 149         }
 150
 151         *next_ust_ctl_field = current + 1;
 152
 153         const auto byte_order = current->type.u._float.reverse_byte_order ?
 154                 lst::type::reverse_byte_order(session_attributes._native_trace_byte_order) :
 155                 session_attributes._native_trace_byte_order;
 156
 157         try {
 158                 return lttng::make_unique<const lst::floating_point_type>(
 159                         current->type.u._float.alignment,
 160                         byte_order,
 161                         current->type.u._float.exp_dig,
 162                         current->type.u._float.mant_dig);
 163         } catch (lttng::invalid_argument_error& ex) {
 164                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 165                         "Invalid floating point attribute in {}: {}", typeid(*current), ex.what()));
 166         }
 167 }
 168
 169 lst::type::cuptr
 170 create_enumeration_type_from_ust_ctl_fields(const lttng_ust_ctl_field *current,
 171                                             const lttng_ust_ctl_field *end,
 172                                             const session_attributes& session_attributes,
 173                                             const lttng_ust_ctl_field **next_ust_ctl_field,
 174                                             lsu::ctl_field_quirks quirks __attribute__((unused)))
 175 {
 176         if (current >= end) {
 177                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 178                         "End of {} array reached unexpectedly during decoding", typeid(*current)));
 179         }
 180
 181         uint64_t enumeration_id;
 182         const auto& enum_uctl_field = *current;
 183         const char *enumeration_name;
 184         const auto *enum_container_uctl_type =
 185                 &current->type.u.legacy.basic.enumeration.container_type;
 186
 187         if (enum_uctl_field.type.atype == lttng_ust_ctl_atype_enum_nestable) {
 188                 /* Nestable enumeration fields are followed by their container type. */
 189                 ++current;
 190                 if (current >= end) {
 191                         LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 192                                 "Array of {} is too short to contain nestable enumeration's container",
 193                                 typeid(*current)));
 194                 }
 195
 196                 if (current->type.atype != lttng_ust_ctl_atype_integer) {
 197                         LTTNG_THROW_PROTOCOL_ERROR(
 198                                 fmt::format("Invalid type of nestable enum container: type id = {}",
 199                                             current->type.atype));
 200                 }
 201
 202                 enum_container_uctl_type = &current->type.u.integer;
 203                 enumeration_id = enum_uctl_field.type.u.enum_nestable.id;
 204                 enumeration_name = enum_uctl_field.type.u.enum_nestable.name;
 205         } else {
 206                 enumeration_id = enum_uctl_field.type.u.legacy.basic.enumeration.id;
 207                 enumeration_name = enum_uctl_field.type.u.legacy.basic.enumeration.name;
 208         }
 209
 210         *next_ust_ctl_field = current + 1;
 211
 212         const auto base = ust_ctl_base_to_integer_field_base(enum_container_uctl_type->base);
 213         const auto byte_order = enum_container_uctl_type->reverse_byte_order ?
 214                 lst::integer_type::reverse_byte_order(session_attributes._native_trace_byte_order) :
 215                 session_attributes._native_trace_byte_order;
 216         const auto signedness = enum_container_uctl_type->signedness ?
 217                 lst::integer_type::signedness::SIGNED :
 218                 lst::integer_type::signedness::UNSIGNED;
 219
 220         if (signedness == lst::integer_type::signedness::SIGNED) {
 221                 const auto& enum_registry = static_cast<const lsu::registry_signed_enum&>(
 222                         *session_attributes.get_registry_enum(enumeration_name, enumeration_id));
 223
 224                 return lttng::make_unique<const lst::signed_enumeration_type>(
 225                         enum_container_uctl_type->alignment,
 226                         byte_order,
 227                         enum_container_uctl_type->size,
 228                         base,
 229                         enum_registry._mappings);
 230         } else {
 231                 const auto& enum_registry = static_cast<const lsu::registry_unsigned_enum&>(
 232                         *session_attributes.get_registry_enum(enumeration_name, enumeration_id));
 233
 234                 return lttng::make_unique<const lst::unsigned_enumeration_type>(
 235                         enum_container_uctl_type->alignment,
 236                         byte_order,
 237                         enum_container_uctl_type->size,
 238                         base,
 239                         enum_registry._mappings);
 240         }
 241 }
 242
 243 lst::type::cuptr
 244 create_string_type_from_ust_ctl_fields(const lttng_ust_ctl_field *current,
 245                                        const lttng_ust_ctl_field *end,
 246                                        const session_attributes& session_attributes
 247                                        __attribute__((unused)),
 248                                        const lttng_ust_ctl_field **next_ust_ctl_field,
 249                                        lsu::ctl_field_quirks quirks __attribute__((unused)))
 250 {
 251         if (current >= end) {
 252                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 253                         "End of {} array reached unexpectedly during decoding", typeid(*current)));
 254         }
 255
 256         const auto& string_uctl_field = *current;
 257         *next_ust_ctl_field = current + 1;
 258
 259         const auto encoding =
 260                 ust_ctl_encoding_to_string_field_encoding(string_uctl_field.type.u.string.encoding);
 261
 262         return lttng::make_unique<const lst::null_terminated_string_type>(1, encoding);
 263 }
 264
 265 lst::type::cuptr
 266 create_integer_type_from_ust_ctl_basic_type(const lttng_ust_ctl_basic_type& type,
 267                                             const session_attributes& session_attributes)
 268 {
 269         /* Checked by caller. */
 270         LTTNG_ASSERT(type.atype == lttng_ust_ctl_atype_integer);
 271
 272         const auto byte_order = type.u.basic.integer.reverse_byte_order ?
 273                 lst::integer_type::reverse_byte_order(session_attributes._native_trace_byte_order) :
 274                 session_attributes._native_trace_byte_order;
 275         const auto signedness = type.u.basic.integer.signedness ?
 276                 lst::integer_type::signedness::SIGNED :
 277                 lst::integer_type::signedness::UNSIGNED;
 278         const auto base = ust_ctl_base_to_integer_field_base(type.u.basic.integer.base);
 279         const auto size = type.u.basic.integer.size;
 280         const auto alignment = type.u.basic.integer.alignment;
 281
 282         return lttng::make_unique<const lst::integer_type>(
 283                 alignment, byte_order, size, signedness, base);
 284 }
 285
 286 lst::type::cuptr
 287 create_array_type_from_ust_ctl_fields(const lttng_ust_ctl_field *current,
 288                                       const lttng_ust_ctl_field *end,
 289                                       const session_attributes& session_attributes,
 290                                       const lttng_ust_ctl_field **next_ust_ctl_field,
 291                                       lsu::ctl_field_quirks quirks __attribute__((unused)))
 292 {
 293         if (current >= end) {
 294                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 295                         "End of {} array reached unexpectedly during decoding", typeid(*current)));
 296         }
 297
 298         const auto& array_uctl_field = *current;
 299         uint32_t array_alignment, array_length;
 300         lst::type::cuptr element_type;
 301         nonstd::optional<enum lst::string_type::encoding> element_encoding;
 302
 303         array_length = array_uctl_field.type.u.legacy.array.length;
 304         array_alignment = 0;
 305
 306         const auto& element_uctl_type = array_uctl_field.type.u.legacy.array.elem_type;
 307         if (element_uctl_type.atype != lttng_ust_ctl_atype_integer) {
 308                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 309                         "Unexpected legacy array element type: atype = {}, expected atype = lttng_ust_ctl_atype_integer ({})",
 310                         element_uctl_type.atype,
 311                         lttng_ust_ctl_atype_integer));
 312         }
 313
 314         element_type =
 315                 create_integer_type_from_ust_ctl_basic_type(element_uctl_type, session_attributes);
 316         if (element_uctl_type.atype == lttng_ust_ctl_atype_integer &&
 317             element_uctl_type.u.basic.integer.encoding != lttng_ust_ctl_encode_none) {
 318                 /* Element represents a text character. */
 319                 element_encoding = ust_ctl_encoding_to_string_field_encoding(
 320                         element_uctl_type.u.basic.integer.encoding);
 321         }
 322
 323         *next_ust_ctl_field = current + 1;
 324
 325         if (element_encoding) {
 326                 const auto integer_element_size =
 327                         static_cast<const lst::integer_type&>(*element_type).size;
 328
 329                 if (integer_element_size != 8) {
 330                         LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 331                                 "Unexpected legacy array element type: integer has encoding but size is not 8: size = {}",
 332                                 integer_element_size));
 333                 }
 334
 335                 /* Array is a static-length string. */
 336                 return lttng::make_unique<lst::static_length_string_type>(
 337                         array_alignment, *element_encoding, array_length);
 338         }
 339
 340         return lttng::make_unique<lst::static_length_array_type>(
 341                 array_alignment, std::move(element_type), array_length);
 342 }
 343
 344 lst::type::cuptr create_array_nestable_type_from_ust_ctl_fields(
 345         const lttng_ust_ctl_field *current,
 346         const lttng_ust_ctl_field *end,
 347         const session_attributes& session_attributes,
 348         const lttng_ust_ctl_field **next_ust_ctl_field,
 349         publish_field_fn publish_field,
 350         lookup_field_fn lookup_field,
 351         lst::field_location::root lookup_root,
 352         lst::field_location::elements& current_field_location_elements,
 353         lsu::ctl_field_quirks quirks)
 354 {
 355         if (current >= end) {
 356                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 357                         "End of {} array reached unexpectedly during decoding", typeid(*current)));
 358         }
 359
 360         const auto& array_uctl_field = *current;
 361         uint32_t array_alignment, array_length;
 362         lst::type::cuptr element_type;
 363         nonstd::optional<enum lst::string_type::encoding> element_encoding;
 364
 365         array_length = array_uctl_field.type.u.array_nestable.length;
 366         array_alignment = array_uctl_field.type.u.array_nestable.alignment;
 367
 368         /* Nestable array fields are followed by their element type. */
 369         const auto& element_uctl_field = *(current + 1);
 370
 371         /* next_ust_ctl_field is updated as needed. */
 372         element_type = create_type_from_ust_ctl_fields(&element_uctl_field,
 373                                                        end,
 374                                                        session_attributes,
 375                                                        next_ust_ctl_field,
 376                                                        publish_field,
 377                                                        lookup_field,
 378                                                        lookup_root,
 379                                                        current_field_location_elements,
 380                                                        quirks);
 381         if (element_uctl_field.type.atype == lttng_ust_ctl_atype_integer &&
 382             element_uctl_field.type.u.integer.encoding != lttng_ust_ctl_encode_none) {
 383                 /* Element represents a text character. */
 384                 element_encoding = ust_ctl_encoding_to_string_field_encoding(
 385                         element_uctl_field.type.u.integer.encoding);
 386         }
 387
 388         if (element_encoding) {
 389                 const auto integer_element_size =
 390                         static_cast<const lst::integer_type&>(*element_type).size;
 391
 392                 if (integer_element_size != 8) {
 393                         LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 394                                 "Unexpected array element type: integer has encoding but size is not 8: size = {}",
 395                                 integer_element_size));
 396                 }
 397
 398                 /* Array is a static-length string. */
 399                 return lttng::make_unique<lst::static_length_string_type>(
 400                         array_alignment, *element_encoding, array_length);
 401         }
 402
 403         return lttng::make_unique<lst::static_length_array_type>(
 404                 array_alignment, std::move(element_type), array_length);
 405 }
 406
 407 /*
 408  * For legacy sequence types, LTTng-UST expresses both the sequence and sequence
 409  * length as part of the same lttng_ust_ctl_field entry.
 410  */
 411 lst::type::cuptr create_sequence_type_from_ust_ctl_fields(
 412         const lttng_ust_ctl_field *current,
 413         const lttng_ust_ctl_field *end,
 414         const session_attributes& session_attributes,
 415         const lttng_ust_ctl_field **next_ust_ctl_field,
 416         publish_field_fn publish_field,
 417         lst::field_location::root lookup_root,
 418         lst::field_location::elements& current_field_location_elements,
 419         lsu::ctl_field_quirks quirks __attribute__((unused)))
 420 {
 421         if (current >= end) {
 422                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 423                         "End of {} array reached unexpectedly during decoding", typeid(*current)));
 424         }
 425
 426         const auto& sequence_uctl_field = *current;
 427         const auto& element_uctl_type = sequence_uctl_field.type.u.legacy.sequence.elem_type;
 428         const auto& length_uctl_type = sequence_uctl_field.type.u.legacy.sequence.length_type;
 429         const auto sequence_alignment = 0U;
 430
 431         if (element_uctl_type.atype != lttng_ust_ctl_atype_integer) {
 432                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 433                         "Unexpected legacy sequence element type: atype = {}, expected atype = lttng_ust_ctl_atype_integer ({})",
 434                         element_uctl_type.atype,
 435                         lttng_ust_ctl_atype_integer));
 436         }
 437
 438         if (length_uctl_type.atype != lttng_ust_ctl_atype_integer) {
 439                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 440                         "Unexpected legacy sequence length field type: atype = {}, expected atype = lttng_ust_ctl_atype_integer ({})",
 441                         length_uctl_type.atype,
 442                         lttng_ust_ctl_atype_integer));
 443         }
 444
 445         nonstd::optional<enum lst::string_type::encoding> element_encoding;
 446         if (element_uctl_type.atype == lttng_ust_ctl_atype_integer &&
 447             element_uctl_type.u.basic.integer.encoding != lttng_ust_ctl_encode_none) {
 448                 /* Element represents a text character. */
 449                 element_encoding = ust_ctl_encoding_to_string_field_encoding(
 450                         element_uctl_type.u.basic.integer.encoding);
 451         }
 452
 453         const auto length_field_name = fmt::format("_{}_length", sequence_uctl_field.name);
 454         auto element_type =
 455                 create_integer_type_from_ust_ctl_basic_type(element_uctl_type, session_attributes);
 456         auto length_type =
 457                 create_integer_type_from_ust_ctl_basic_type(length_uctl_type, session_attributes);
 458
 459         lst::field_location::elements length_field_location_elements =
 460                 current_field_location_elements;
 461         length_field_location_elements.emplace_back(length_field_name);
 462
 463         const lst::field_location length_field_location{
 464                 lookup_root, std::move(length_field_location_elements)
 465         };
 466
 467         /* Publish an implicit length field _before_ the sequence field. */
 468         publish_field(lttng::make_unique<lst::field>(std::move(length_field_name),
 469                                                      std::move(length_type)));
 470
 471         *next_ust_ctl_field = current + 1;
 472
 473         if (element_encoding) {
 474                 const auto integer_element_size =
 475                         static_cast<const lst::integer_type&>(*element_type).size;
 476
 477                 if (integer_element_size != 8) {
 478                         LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 479                                 "Unexpected legacy array element type: integer has encoding but size is not 8: size = {}",
 480                                 integer_element_size));
 481                 }
 482
 483                 /* Sequence is a dynamic-length string. */
 484                 return lttng::make_unique<lst::dynamic_length_string_type>(
 485                         sequence_alignment, *element_encoding, std::move(length_field_location));
 486         }
 487
 488         return lttng::make_unique<lst::dynamic_length_array_type>(
 489                 sequence_alignment, std::move(element_type), std::move(length_field_location));
 490 }
 491
 492 lst::type::cuptr create_sequence_nestable_type_from_ust_ctl_fields(
 493         const lttng_ust_ctl_field *current,
 494         const lttng_ust_ctl_field *end,
 495         const session_attributes& session_attributes,
 496         const lttng_ust_ctl_field **next_ust_ctl_field,
 497         publish_field_fn publish_field,
 498         lookup_field_fn lookup_field,
 499         lst::field_location::root lookup_root,
 500         lst::field_location::elements& current_field_location_elements,
 501         lsu::ctl_field_quirks quirks)
 502 {
 503         if (current >= end) {
 504                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 505                         "End of {} array reached unexpectedly during decoding", typeid(*current)));
 506         }
 507
 508         const auto& sequence_uctl_field = *current;
 509         const auto sequence_alignment = sequence_uctl_field.type.u.sequence_nestable.alignment;
 510         const auto *length_field_name = sequence_uctl_field.type.u.sequence_nestable.length_name;
 511
 512         /* Nestable sequence fields are followed by their element type. */
 513         const auto& element_uctl_field = *(current + 1);
 514
 515         nonstd::optional<enum lst::string_type::encoding> element_encoding;
 516         if (element_uctl_field.type.atype == lttng_ust_ctl_atype_integer &&
 517             element_uctl_field.type.u.integer.encoding != lttng_ust_ctl_encode_none) {
 518                 /* Element represents a text character. */
 519                 element_encoding = ust_ctl_encoding_to_string_field_encoding(
 520                         element_uctl_field.type.u.integer.encoding);
 521         }
 522
 523         /* next_ust_ctl_field is updated as needed. */
 524         auto element_type = create_type_from_ust_ctl_fields(&element_uctl_field,
 525                                                             end,
 526                                                             session_attributes,
 527                                                             next_ust_ctl_field,
 528                                                             publish_field,
 529                                                             lookup_field,
 530                                                             lookup_root,
 531                                                             current_field_location_elements,
 532                                                             quirks);
 533
 534         if (lttng_strnlen(sequence_uctl_field.type.u.sequence_nestable.length_name,
 535                           sizeof(sequence_uctl_field.type.u.sequence_nestable.length_name)) ==
 536             sizeof(sequence_uctl_field.type.u.sequence_nestable.length_name)) {
 537                 LTTNG_THROW_PROTOCOL_ERROR("Sequence length field name is not null terminated");
 538         }
 539
 540         lst::field_location::elements length_field_location_elements =
 541                 current_field_location_elements;
 542         length_field_location_elements.emplace_back(std::move(length_field_name));
 543
 544         const lst::field_location length_field_location{
 545                 lookup_root, std::move(length_field_location_elements)
 546         };
 547
 548         /* Validate existence of length field (throws if not found). */
 549         const auto& length_field = lookup_field(length_field_location);
 550         const auto *integer_selector_field =
 551                 dynamic_cast<const lst::integer_type *>(&length_field.get_type());
 552         if (!integer_selector_field) {
 553                 LTTNG_THROW_PROTOCOL_ERROR(
 554                         "Invalid selector field type referenced from sequence: expected integer or enumeration");
 555         }
 556
 557         if (element_encoding) {
 558                 const auto integer_element_size =
 559                         static_cast<const lst::integer_type&>(*element_type).size;
 560
 561                 if (integer_element_size != 8) {
 562                         LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 563                                 "Unexpected array element type: integer has encoding but size is not 8: size = {}",
 564                                 integer_element_size));
 565                 }
 566
 567                 /* Sqeuence is a dynamic-length string. */
 568                 return lttng::make_unique<lst::dynamic_length_string_type>(
 569                         sequence_alignment, *element_encoding, std::move(length_field_location));
 570         }
 571
 572         return lttng::make_unique<lst::dynamic_length_array_type>(
 573                 sequence_alignment, std::move(element_type), std::move(length_field_location));
 574 }
 575
 576 lst::type::cuptr
 577 create_structure_field_from_ust_ctl_fields(const lttng_ust_ctl_field *current,
 578                                            const lttng_ust_ctl_field *end,
 579                                            const session_attributes& session_attributes
 580                                            __attribute__((unused)),
 581                                            const lttng_ust_ctl_field **next_ust_ctl_field,
 582                                            lsu::ctl_field_quirks quirks __attribute__((unused)))
 583 {
 584         if (current >= end) {
 585                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 586                         "End of {} array reached unexpectedly during decoding", typeid(*current)));
 587         }
 588
 589         uint32_t field_count;
 590         uint32_t alignment;
 591         const auto& structure_uctl_field = *current;
 592
 593         if (structure_uctl_field.type.atype == lttng_ust_ctl_atype_struct) {
 594                 field_count = structure_uctl_field.type.u.legacy._struct.nr_fields;
 595                 alignment = 0;
 596         } else {
 597                 field_count = structure_uctl_field.type.u.struct_nestable.nr_fields;
 598                 alignment = structure_uctl_field.type.u.struct_nestable.alignment;
 599         }
 600
 601         if (field_count != 0) {
 602                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 603                         "Only empty structures are supported by LTTng-UST: nr_fields = {}",
 604                         field_count));
 605         }
 606
 607         *next_ust_ctl_field = current + 1;
 608         return lttng::make_unique<lst::structure_type>(alignment, lst::structure_type::fields());
 609 }
 610
 611 template <class VariantSelectorMappingIntegerType>
 612 typename lst::variant_type<VariantSelectorMappingIntegerType>::choices
 613 create_typed_variant_choices(const lttng_ust_ctl_field *current,
 614                              const lttng_ust_ctl_field *end,
 615                              const session_attributes& session_attributes,
 616                              const lttng_ust_ctl_field **next_ust_ctl_field,
 617                              lookup_field_fn lookup_field,
 618                              lst::field_location::root lookup_root,
 619                              lst::field_location::elements& current_field_location_elements,
 620                              unsigned int choice_count,
 621                              const lst::field& selector_field,
 622                              lsu::ctl_field_quirks quirks)
 623 {
 624         typename lst::variant_type<VariantSelectorMappingIntegerType>::choices choices;
 625         const auto& typed_enumeration =
 626                 static_cast<const lst::typed_enumeration_type<VariantSelectorMappingIntegerType>&>(
 627                         selector_field.get_type());
 628
 629         for (unsigned int i = 0; i < choice_count; i++) {
 630                 create_field_from_ust_ctl_fields(
 631                         current,
 632                         end,
 633                         session_attributes,
 634                         next_ust_ctl_field,
 635                         [&choices, typed_enumeration, &selector_field, quirks](
 636                                 lst::field::uptr field) {
 637                                 /*
 638                                  * Find the enumeration mapping that matches the
 639                                  * field's name.
 640                                  */
 641                                 const auto mapping_it = std::find_if(
 642                                         typed_enumeration.mappings_->begin(),
 643                                         typed_enumeration.mappings_->end(),
 644                                         [&field,
 645                                          quirks](const typename std::remove_reference<
 646                                                  decltype(typed_enumeration)>::type::mapping&
 647                                                          mapping) {
 648                                                 if (static_cast<bool>(
 649                                                             quirks &
 650                                                             lsu::ctl_field_quirks::
 651                                                                     UNDERSCORE_PREFIXED_VARIANT_TAG_MAPPINGS)) {
 652                                                         /*
 653                                                          * Check if they match with
 654                                                          * a prepended underscore
 655                                                          * and, if not, perform the
 656                                                          * regular check.
 657                                                          */
 658                                                         if ((std::string("_") + field->name) ==
 659                                                             mapping.name) {
 660                                                                 return true;
 661                                                         }
 662                                                 }
 663
 664                                                 return mapping.name == field->name;
 665                                         });
 666
 667                                 if (mapping_it == typed_enumeration.mappings_->end()) {
 668                                         LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 669                                                 "Invalid variant choice: `{}` does not match any mapping in `{}` enumeration",
 670                                                 field->name,
 671                                                 selector_field.name));
 672                                 }
 673
 674                                 choices.emplace_back(*mapping_it, field->move_type());
 675                         },
 676                         lookup_field,
 677                         lookup_root,
 678                         current_field_location_elements,
 679                         quirks);
 680
 681                 current = *next_ust_ctl_field;
 682         }
 683
 684         return choices;
 685 }
 686
 687 lst::type::cuptr create_variant_field_from_ust_ctl_fields(
 688         const lttng_ust_ctl_field *current,
 689         const lttng_ust_ctl_field *end,
 690         const session_attributes& session_attributes,
 691         const lttng_ust_ctl_field **next_ust_ctl_field,
 692         lookup_field_fn lookup_field,
 693         lst::field_location::root lookup_root,
 694         lst::field_location::elements& current_field_location_elements,
 695         lsu::ctl_field_quirks quirks)
 696 {
 697         if (current >= end) {
 698                 LTTNG_THROW_PROTOCOL_ERROR(fmt::format(
 699                         "End of {} array reached unexpectedly during decoding", typeid(*current)));
 700         }
 701
 702         const auto& variant_uctl_field = *current;
 703         current++;
 704
 705         uint32_t alignment;
 706         uint32_t choice_count;
 707         const char *tag_name;
 708
 709         if (variant_uctl_field.type.atype == lttng_ust_ctl_atype_variant) {
 710                 alignment = 0;
 711                 choice_count = variant_uctl_field.type.u.legacy.variant.nr_choices;
 712                 tag_name = variant_uctl_field.type.u.legacy.variant.tag_name;
 713         } else {
 714                 alignment = variant_uctl_field.type.u.variant_nestable.alignment;
 715                 choice_count = variant_uctl_field.type.u.variant_nestable.nr_choices;
 716                 tag_name = variant_uctl_field.type.u.variant_nestable.tag_name;
 717         }
 718
 719         lst::field_location::elements selector_field_location_elements =
 720                 current_field_location_elements;
 721         selector_field_location_elements.emplace_back(tag_name);
 722
 723         const lst::field_location selector_field_location{
 724                 lookup_root, std::move(selector_field_location_elements)
 725         };
 726
 727         /* Validate existence of selector field (throws if not found). */
 728         const auto& selector_field = lookup_field(selector_field_location);
 729         const auto *enumeration_selector_type =
 730                 dynamic_cast<const lst::enumeration_type *>(&selector_field.get_type());
 731         if (!enumeration_selector_type) {
 732                 LTTNG_THROW_PROTOCOL_ERROR(
 733                         "Invalid selector field type referenced from variant: expected enumeration");
 734         }
 735
 736         const bool selector_is_signed = enumeration_selector_type->signedness_ ==
 737                 lst::integer_type::signedness::SIGNED;
 738
 739         /* Choices follow. next_ust_ctl_field is updated as needed. */
 740         if (selector_is_signed) {
 741                 lst::variant_type<lst::signed_enumeration_type::mapping::range_t::range_integer_t>::
 742                         choices choices = create_typed_variant_choices<int64_t>(
 743                                 current,
 744                                 end,
 745                                 session_attributes,
 746                                 next_ust_ctl_field,
 747                                 lookup_field,
 748                                 lookup_root,
 749                                 current_field_location_elements,
 750                                 choice_count,
 751                                 selector_field,
 752                                 quirks);
 753
 754                 return lttng::make_unique<lst::variant_type<int64_t>>(
 755                         alignment, std::move(selector_field_location), std::move(choices));
 756         } else {
 757                 lst::variant_type<
 758                         lst::unsigned_enumeration_type::mapping::range_t::range_integer_t>::choices
 759                         choices = create_typed_variant_choices<uint64_t>(
 760                                 current,
 761                                 end,
 762                                 session_attributes,
 763                                 next_ust_ctl_field,
 764                                 lookup_field,
 765                                 lookup_root,
 766                                 current_field_location_elements,
 767                                 choice_count,
 768                                 selector_field,
 769                                 quirks);
 770
 771                 return lttng::make_unique<lst::variant_type<uint64_t>>(
 772                         alignment, std::move(selector_field_location), std::move(choices));
 773         }
 774 }
 775
 776 lst::type::cuptr
 777 create_type_from_ust_ctl_fields(const lttng_ust_ctl_field *current,
 778                                 const lttng_ust_ctl_field *end,
 779                                 const session_attributes& session_attributes,
 780                                 const lttng_ust_ctl_field **next_ust_ctl_field,
 781                                 publish_field_fn publish_field,
 782                                 lookup_field_fn lookup_field,
 783                                 lst::field_location::root lookup_root,
 784                                 lst::field_location::elements& current_field_location_elements,
 785                                 lsu::ctl_field_quirks quirks)
 786 {
 787         switch (current->type.atype) {
 788         case lttng_ust_ctl_atype_integer:
 789                 return create_integer_type_from_ust_ctl_fields(
 790                         current, end, session_attributes, next_ust_ctl_field, quirks);
 791         case lttng_ust_ctl_atype_enum:
 792         case lttng_ust_ctl_atype_enum_nestable:
 793                 return create_enumeration_type_from_ust_ctl_fields(
 794                         current, end, session_attributes, next_ust_ctl_field, quirks);
 795         case lttng_ust_ctl_atype_float:
 796                 return create_floating_point_type_from_ust_ctl_fields(
 797                         current, end, session_attributes, next_ust_ctl_field, quirks);
 798         case lttng_ust_ctl_atype_string:
 799                 return create_string_type_from_ust_ctl_fields(
 800                         current, end, session_attributes, next_ust_ctl_field, quirks);
 801         case lttng_ust_ctl_atype_array:
 802                 return create_array_type_from_ust_ctl_fields(
 803                         current, end, session_attributes, next_ust_ctl_field, quirks);
 804         case lttng_ust_ctl_atype_array_nestable:
 805                 return create_array_nestable_type_from_ust_ctl_fields(
 806                         current,
 807                         end,
 808                         session_attributes,
 809                         next_ust_ctl_field,
 810                         publish_field,
 811                         lookup_field,
 812                         lookup_root,
 813                         current_field_location_elements,
 814                         quirks);
 815         case lttng_ust_ctl_atype_sequence:
 816                 return create_sequence_type_from_ust_ctl_fields(current,
 817                                                                 end,
 818                                                                 session_attributes,
 819                                                                 next_ust_ctl_field,
 820                                                                 publish_field,
 821                                                                 lookup_root,
 822                                                                 current_field_location_elements,
 823                                                                 quirks);
 824         case lttng_ust_ctl_atype_sequence_nestable:
 825                 return create_sequence_nestable_type_from_ust_ctl_fields(
 826                         current,
 827                         end,
 828                         session_attributes,
 829                         next_ust_ctl_field,
 830                         publish_field,
 831                         lookup_field,
 832                         lookup_root,
 833                         current_field_location_elements,
 834                         quirks);
 835         case lttng_ust_ctl_atype_struct:
 836         case lttng_ust_ctl_atype_struct_nestable:
 837                 return create_structure_field_from_ust_ctl_fields(
 838                         current, end, session_attributes, next_ust_ctl_field, quirks);
 839         case lttng_ust_ctl_atype_variant:
 840         case lttng_ust_ctl_atype_variant_nestable:
 841                 return create_variant_field_from_ust_ctl_fields(current,
 842                                                                 end,
 843                                                                 session_attributes,
 844                                                                 next_ust_ctl_field,
 845                                                                 lookup_field,
 846                                                                 lookup_root,
 847                                                                 current_field_location_elements,
 848                                                                 quirks);
 849         default:
 850                 LTTNG_THROW_PROTOCOL_ERROR(
 851                         fmt::format("Unknown {} value `{}` encountered while converting {} to {}",
 852                                     typeid(current->type.atype),
 853                                     current->type.atype,
 854                                     typeid(*current),
 855                                     typeid(lst::type::cuptr::element_type)));
 856         }
 857 }
 858
 859 void create_field_from_ust_ctl_fields(const lttng_ust_ctl_field *current,
 860                                       const lttng_ust_ctl_field *end,
 861                                       const session_attributes& session_attributes,
 862                                       const lttng_ust_ctl_field **next_ust_ctl_field,
 863                                       publish_field_fn publish_field,
 864                                       lookup_field_fn lookup_field,
 865                                       lst::field_location::root lookup_root,
 866                                       lst::field_location::elements& current_field_location_elements,
 867                                       lsu::ctl_field_quirks quirks)
 868 {
 869         LTTNG_ASSERT(current < end);
 870
 871         if (lttng_strnlen(current->name, sizeof(current->name)) == sizeof(current->name)) {
 872                 LTTNG_THROW_PROTOCOL_ERROR(
 873                         fmt::format("Name of {} is not null-terminated", typeid(*current)));
 874         }
 875
 876         publish_field(lttng::make_unique<lst::field>(
 877                 current->name,
 878                 create_type_from_ust_ctl_fields(current,
 879                                                 end,
 880                                                 session_attributes,
 881                                                 next_ust_ctl_field,
 882                                                 publish_field,
 883                                                 lookup_field,
 884                                                 lookup_root,
 885                                                 current_field_location_elements,
 886                                                 quirks)));
 887 }
 888
 889 std::vector<lst::field::cuptr>::iterator
 890 lookup_field_in_vector(std::vector<lst::field::cuptr>& fields, const lst::field_location& location)
 891 {
 892         if (location.elements_.size() != 1) {
 893                 LTTNG_THROW_ERROR(fmt::format(
 894                         "Unexpected field location received during field look-up: location = {}",
 895                         location));
 896         }
 897
 898         /*
 899          * In the context of fields received from LTTng-UST, field
 900          * look-up is extremely naive as the protocol can only
 901          * express empty structures. It is safe to assume that
 902          * location has a depth of 1 and directly refers to a field
 903          * in the 'fields' vector.
 904          */
 905         const auto field_it =
 906                 std::find_if(fields.begin(), fields.end(), [location](lst::field::cuptr& field) {
 907                         return field->name == location.elements_[0];
 908                 });
 909
 910         if (field_it == fields.end()) {
 911                 LTTNG_THROW_PROTOCOL_ERROR(
 912                         fmt::format("Failed to look-up field: location = {}", location));
 913         }
 914
 915         return field_it;
 916 }
 917
 918 /*
 919  * `lttng_ust_ctl_field`s can be nested, in which case creating a field will consume
 920  * more than one lttng_ust_ctl_field. create_field_from_ust_ctl_fields returns the
 921  * position of the next lttng_ust_ctl_field to consume or `end` when the last field
 922  * is consumed.
 923  *
 924  * Always returns a new field, throws on error.
 925  */
 926 std::vector<lst::field::cuptr>
 927 create_fields_from_ust_ctl_fields(const lsu::registry_session& session,
 928                                   const lttng_ust_ctl_field *current,
 929                                   const lttng_ust_ctl_field *end,
 930                                   lst::field_location::root lookup_root,
 931                                   lsu::ctl_field_quirks quirks)
 932 {
 933         std::vector<lst::field::cuptr> fields;
 934         const auto trace_native_byte_order = session.abi.byte_order;
 935         const session_attributes session_attributes{
 936                 [&session](const char *enum_name, uint64_t enum_id) {
 937                         return session.enumeration(enum_name, enum_id);
 938                 },
 939                 trace_native_byte_order
 940         };
 941         /* Location of field being created. */
 942         lst::field_location::elements current_field_location_elements;
 943
 944         while (current < end) {
 945                 auto *next_field = current;
 946
 947                 /*
 948                  * create_field_from_ust_ctl_fields will consume one field at a time.
 949                  * However, some fields expressed by LTTng-UST's protocol are expended
 950                  * to multiple event fields (legacy sequence fields implicitly define
 951                  * their length field).
 952                  *
 953                  * The lambda allows the factory functions to push as many fields as
 954                  * needed depending on the decoded field's type.
 955                  */
 956                 create_field_from_ust_ctl_fields(
 957                         current,
 958                         end,
 959                         session_attributes,
 960                         &next_field,
 961                         [&fields](lst::field::cuptr field) {
 962                                 /* Publishing a field simply adds it to the converted
 963                                  * fields. */
 964                                 fields.emplace_back(std::move(field));
 965                         },
 966                         [&fields](const lst::field_location& location)
 967                                 -> lookup_field_fn::result_type {
 968                                 /* Resolve location to a previously-constructed field. */
 969                                 return **lookup_field_in_vector(fields, location);
 970                         },
 971                         lookup_root,
 972                         current_field_location_elements,
 973                         quirks);
 974
 975                 current = next_field;
 976         }
 977
 978         return fields;
 979 }
 980 } /* namespace */
 981
 982 std::vector<lst::field::cuptr>
 983 lsu::create_trace_fields_from_ust_ctl_fields(const lsu::registry_session& session,
 984                                              const lttng_ust_ctl_field *fields,
 985                                              std::size_t field_count,
 986                                              lst::field_location::root lookup_root,
 987                                              lsu::ctl_field_quirks quirks)
 988 {
 989         return create_fields_from_ust_ctl_fields(
 990                 session, fields, fields + field_count, lookup_root, quirks);
 991 }