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