FunctionVariants.hpp

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/* Copyright 2017 - 2026 R. Thomas
 * Copyright 2017 - 2026 Quarkslab
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef LIEF_MACHO_FUNCTION_VARIANTS_COMMAND_H
#define LIEF_MACHO_FUNCTION_VARIANTS_COMMAND_H
#include <vector>
#include <ostream>
 
#include "LIEF/compiler_attributes.hpp"
#include "LIEF/visibility.h"
#include "LIEF/errors.hpp"
#include "LIEF/iterators.hpp"
 
#include "LIEF/MachO/LoadCommand.hpp"
 
namespace LIEF {
class SpanStream;
class BinaryStream;
 
namespace MachO {
class BinaryParser;
class LinkEdit;
 
namespace details {
struct linkedit_data_command;
 
// clang-format off
// On-disk entry of a `LC_FUNCTION_VARIANTS` runtime table
struct runtime_table_entry_t {
  uint32_t impl          : 31,
           another_table : 1;
  uint8_t flag_bit_nums[4];
};
// clang-format on
 
}

class LIEF_API FunctionVariants : public LoadCommand {
  friend class BinaryParser;
  friend class LinkEdit;
 
  public:
  class LIEF_API RuntimeTableEntry {
    public:
    static constexpr uint32_t MAX_IMPL = (uint32_t(1) << 31) - 1;
 
    static constexpr uint32_t F_BIT = 20;
    static constexpr uint32_t F_MASK = (uint32_t(1) << F_BIT) - 1;
 
    static constexpr uint32_t F_PER_PROCESS = uint32_t(1) << F_BIT;
    static constexpr uint32_t F_SYSTEM_WIDE = uint32_t(2) << F_BIT;
    static constexpr uint32_t F_ARM64 = uint32_t(3) << F_BIT;
    static constexpr uint32_t F_X86_64 = uint32_t(4) << F_BIT;

    enum class FLAGS : uint32_t {
      UNKNOWN = 0,
 
#define FUNCTION_VARIANT_FLAG(name, value, _) name = (value | F_ARM64),
#include "LIEF/MachO/FunctionVariants/Arm64.def"
#undef FUNCTION_VARIANT_FLAG
 
#define FUNCTION_VARIANT_FLAG(name, value, _) name = (value | F_X86_64),
#include "LIEF/MachO/FunctionVariants/X86_64.def"
#undef FUNCTION_VARIANT_FLAG
 
#define FUNCTION_VARIANT_FLAG(name, value, _) name = (value | F_SYSTEM_WIDE),
#include "LIEF/MachO/FunctionVariants/SystemWide.def"
#undef FUNCTION_VARIANT_FLAG
 
#define FUNCTION_VARIANT_FLAG(name, value, _) name = (value | F_PER_PROCESS),
#include "LIEF/MachO/FunctionVariants/PerProcess.def"
#undef FUNCTION_VARIANT_FLAG
    };
 
    static uint8_t get_raw(FLAGS f) {
      return (uint8_t)f;
    }
 
    RuntimeTableEntry() = default;
    RuntimeTableEntry(const details::runtime_table_entry_t& entry);
 
    RuntimeTableEntry(const RuntimeTableEntry&) = default;
    RuntimeTableEntry& operator=(const RuntimeTableEntry&) = default;
 
    RuntimeTableEntry(RuntimeTableEntry&&) noexcept = default;
    RuntimeTableEntry& operator=(RuntimeTableEntry&&) noexcept = default;
 
    ~RuntimeTableEntry() = default;

    uint32_t impl() const {
      return impl_;
    }

    void impl(uint32_t value) {
      impl_ = value & MAX_IMPL;
    }

    bool another_table() const {
      return another_table_;
    }

    void another_table(bool value) {
      another_table_ = value;
    }

    span<const uint8_t> flag_bit_nums() const LIEF_LIFETIMEBOUND {
      return flag_bit_nums_;
    }

    const std::vector<FLAGS>& flags() const {
      return flags_;
    }
 
    std::string to_string() const;
 
    LIEF_API friend std::ostream& operator<<(std::ostream& os,
                                             const RuntimeTableEntry& entry) {
      os << entry.to_string();
      return os;
    }

    LIEF_LOCAL void set_flags(std::vector<FLAGS> flags) {
      flags_ = std::move(flags);
    }
 
    private:
    bool another_table_ = false;
    uint32_t impl_ = 0;
    std::array<uint8_t, 4> flag_bit_nums_ = {};
    std::vector<FLAGS> flags_;
  };

  class LIEF_API RuntimeTable {
    public:
    using entries_t = std::vector<RuntimeTableEntry>;

    using it_entries = ref_iterator<entries_t&>;

    using it_const_entries = const_ref_iterator<const entries_t&>;

    enum class KIND : uint32_t {
      UNKNOWN = 0,

      PER_PROCESS = 1,

      SYSTEM_WIDE = 2,

      ARM64 = 3,

      X86_64 = 4,
    };
 
    RuntimeTable() = default;
    RuntimeTable(KIND kind, uint32_t offset) :
      kind_(kind),
      offset_(offset) {}
    RuntimeTable(const RuntimeTable&) = default;
    RuntimeTable& operator=(const RuntimeTable&) = default;
 
    RuntimeTable(RuntimeTable&&) noexcept = default;
    RuntimeTable& operator=(RuntimeTable&&) noexcept = default;
 
    ~RuntimeTable() = default;

    KIND kind() const {
      return kind_;
    }

    uint32_t offset() const {
      return offset_;
    }

    it_entries entries() LIEF_LIFETIMEBOUND {
      return entries_;
    }
 
    it_const_entries entries() const LIEF_LIFETIMEBOUND {
      return entries_;
    }
 
    void add(RuntimeTableEntry entry) {
      entries_.push_back(std::move(entry));
    }
 
    std::string to_string() const;
 
    LIEF_API friend std::ostream& operator<<(std::ostream& os,
                                             const RuntimeTable& table) {
      os << table.to_string();
      return os;
    }
 
    private:
    KIND kind_ = KIND::UNKNOWN;
    uint32_t offset_ = 0;
    entries_t entries_;
  };
 
  using runtime_table_t = std::vector<RuntimeTable>;

  using it_runtime_table = ref_iterator<runtime_table_t&>;

  using it_const_runtime_table = const_ref_iterator<const runtime_table_t&>;
 
  FunctionVariants() = default;
  FunctionVariants(const details::linkedit_data_command& cmd);
 
  FunctionVariants& operator=(const FunctionVariants& copy) = default;
  FunctionVariants(const FunctionVariants& copy) = default;
 
  std::unique_ptr<LoadCommand> clone() const override {
    return std::unique_ptr<FunctionVariants>(new FunctionVariants(*this));
  }

  uint32_t data_offset() const {
    return data_offset_;
  }

  uint32_t data_size() const {
    return data_size_;
  }
 
  void data_offset(uint32_t offset) {
    data_offset_ = offset;
  }
 
  void data_size(uint32_t size) {
    data_size_ = size;
  }

  span<const uint8_t> content() const LIEF_LIFETIMEBOUND {
    return content_;
  }
 
  span<uint8_t> content() LIEF_LIFETIMEBOUND {
    return content_;
  }

  it_runtime_table runtime_table() LIEF_LIFETIMEBOUND {
    return runtime_table_;
  }
 
  it_const_runtime_table runtime_table() const LIEF_LIFETIMEBOUND {
    return runtime_table_;
  }

  RuntimeTable& add(RuntimeTable table) LIEF_LIFETIMEBOUND {
    runtime_table_.push_back(std::move(table));
    return runtime_table_.back();
  }
 
  ~FunctionVariants() override = default;
 
  std::ostream& print(std::ostream& os) const override;
 
  static bool classof(const LoadCommand* cmd) {
    return cmd->command() == LoadCommand::TYPE::FUNCTION_VARIANTS;
  }
 
  LIEF_LOCAL static std::vector<RuntimeTable> parse_payload(SpanStream& stream);
  LIEF_LOCAL static result<RuntimeTable> parse_entry(BinaryStream& stream);
 
  private:
  uint32_t data_offset_ = 0;
  uint32_t data_size_ = 0;
  span<uint8_t> content_;
  std::vector<RuntimeTable> runtime_table_;
};
 
LIEF_API const char* to_string(FunctionVariants::RuntimeTable::KIND kind);
LIEF_API const char* to_string(FunctionVariants::RuntimeTableEntry::FLAGS kind);
 
}
}
#endif