libs: extract multiboot library

7 files changed, 591 insertions, 0 deletions

diff --git a/libs/multiboot2/CMakeLists.txt b/libs/multiboot2/CMakeLists.txt
new file mode 100644
index 0000000..af56d5a
--- /dev/null
+++ b/libs/multiboot2/CMakeLists.txt
@@ -0,0 +1,26 @@
+cmake_minimum_required(VERSION "3.27")
+
+project("multiboot2"
+    LANGUAGES CXX
+    VERSION "1.0.0"
+)
+
+add_library("multiboot2" INTERFACE)
+add_library("multiboot2::multiboot2" ALIAS "multiboot2")
+
+target_sources("multiboot2" INTERFACE
+    FILE_SET HEADERS
+    BASE_DIRS "include"
+    FILES
+    "include/multiboot2/constants.hpp"
+    "include/multiboot2/information.hpp"
+
+    "include/multiboot2/impl/data.hpp"
+    "include/multiboot2/impl/ids.hpp"
+    "include/multiboot2/impl/iterator.hpp"
+    "include/multiboot2/impl/tag.hpp"
+)
+
+target_include_directories("multiboot2" INTERFACE
+    "include"
+)
diff --git a/libs/multiboot2/include/multiboot2/constants.hpp b/libs/multiboot2/include/multiboot2/constants.hpp
new file mode 100644
index 0000000..30d52d0
--- /dev/null
+++ b/libs/multiboot2/include/multiboot2/constants.hpp
@@ -0,0 +1,20 @@
+#ifndef MULTIBOOT2_CONSTANTS_HPP
+#define MULTIBOOT2_CONSTANTS_HPP
+
+#include "impl/ids.hpp"  // IWYU pragma: export
+
+#include <cstdint>
+
+namespace multiboot2
+{
+
+  using impl::architecture_id;
+  using impl::information_id;
+  using impl::memory_type;
+  using impl::tag_id;
+
+  auto constexpr inline header_magic = std::uint32_t{0xe85250d6};
+
+}  // namespace multiboot2
+
+#endif
diff --git a/libs/multiboot2/include/multiboot2/impl/data.hpp b/libs/multiboot2/include/multiboot2/impl/data.hpp
new file mode 100644
index 0000000..367e8cb
--- /dev/null
+++ b/libs/multiboot2/include/multiboot2/impl/data.hpp
@@ -0,0 +1,130 @@
+#ifndef MULTIBOOT2_IMPL_DATA_HPP
+#define MULTIBOOT2_IMPL_DATA_HPP
+
+#include "multiboot2/impl/ids.hpp"
+
+#include <cstdint>
+
+namespace multiboot2::impl
+{
+  template<auto Id>
+  struct tag_data
+  {
+    auto constexpr inline static id = Id;
+  };
+
+  /**
+   * @brief Basic system memory information
+   */
+  struct basic_memory_data : tag_data<information_id::BASIC_MEMORY_INFO>
+  {
+    /**
+     * @brief Amount of lower memory (below 1MiB) available to the system.
+     *
+     * The maximum possible value for this field is 640 KiB.
+     */
+    std::uint32_t const lower_KiB;
+
+    /**
+     * @brief Amount of upper memory (above 1MiB) available to the system.
+     *
+     * The maximum possible value for this field is the address of the first upper memory hole minus 1MiB.
+     */
+    std::uint32_t const upper_KiB;
+  };
+
+  /**
+   * @brief Device the image got loaded from
+   */
+  struct bios_boot_device_data : tag_data<information_id::BOOTDEV>
+  {
+    /**
+     * @brief BIOS device number as understood by INT 13h.
+     */
+    std::uint32_t device_number;
+
+    /**
+     * @brief Number of the primary partition.
+     */
+    std::uint32_t partition_number;
+
+    /**
+     * @brief Number the sub-partion on the primary partition.
+     */
+    std::uint32_t sub_partition_number;
+  };
+
+  /**
+   * @brief Supplied image command line
+   */
+  struct command_line_data : tag_data<information_id::CMDLINE>
+  {
+    /* This struct intentionally left blank. */
+  };
+
+  /**
+   * @brief ELF symbols of the image
+   */
+  struct elf_symbols_data : tag_data<information_id::ELF_SECTIONS>
+  {
+    std::uint32_t count;
+    std::uint32_t entry_size;
+    std::uint32_t string_table_index;
+  };
+
+  /**
+   * @brief Name of the boot loader
+   */
+  struct loader_name_data : tag_data<information_id::BOOT_LOADER_NAME>
+  {
+    /* This struct intentionally left blank. */
+  };
+
+  /**
+   * @brief Detailed map of the memory regions present in the system
+   *
+   */
+  struct memory_map_data : tag_data<information_id::MEMORY_MAP>
+  {
+    /**
+     * @brief A region of memory
+     */
+    struct region
+    {
+      /**
+       * @brief Check if the memory described by this region is available for use.
+       */
+      auto constexpr available() const noexcept { return type == memory_type::AVAILABLE; }
+
+      /**
+       * @brief Start address of this region
+       */
+      std::uint64_t const base;
+
+      /**
+       * @brief Size of this region in bytes.
+       */
+      std::uint64_t const size_in_B;
+
+      /**
+       * @brief Type of this region.
+       */
+      memory_type const type;
+
+      std::uint32_t : 0;
+    };
+
+    /**
+     * @brief Size of each entry present in the map
+     */
+    std::uint32_t const entry_size;
+
+    /**
+     * @brief Version of each entry present in the map
+     */
+    std::uint32_t const entry_version;
+  };
+
+}  // namespace multiboot2::impl
+
+#endif
\ No newline at end of file
diff --git a/libs/multiboot2/include/multiboot2/impl/ids.hpp b/libs/multiboot2/include/multiboot2/impl/ids.hpp
new file mode 100644
index 0000000..3a7215e
--- /dev/null
+++ b/libs/multiboot2/include/multiboot2/impl/ids.hpp
@@ -0,0 +1,79 @@
+#ifndef MULTIBOOT2_IMPL_IDS_HPP
+#define MULTIBOOT2_IMPL_IDS_HPP
+
+#include <cstdint>
+
+namespace multiboot2::impl
+{
+
+  /**
+   * @brief Information tag IDs.
+   */
+  enum struct information_id : std::uint32_t
+  {
+    END,                    ///< Signals final tag for the multiboot2 information structure.
+    CMDLINE,                ///< Contains the command line string.
+    BOOT_LOADER_NAME,       ///< Contains the name of the boot loader booting the kernel.
+    MODULE,                 ///< Indicates the boot module which was loaded along the kernel image.
+    BASIC_MEMORY_INFO,      ///< Contains the amount of lower (0MB start address) and upper memory (1MB start address).
+    BOOTDEV,                ///< Indicates which BIOS disk device the hoot loader has loaded the OS image from.
+    MEMORY_MAP,             ///< Describes the memory layout of the system with individual areas and their flags.
+    VBE_INFO,               ///< Includes information to access and utilize the device GPU.
+    FRAMEBUFFER,            ///< VBE framebuffer information.
+    ELF_SECTIONS,           ///< Includes list of all section headers from the loaded ELF kernel.
+    APM_INFO,               ///< Advanced Power Management information.
+    EFI32,                  ///< EFI 32 bit system table pointer.
+    EFI64,                  ///< EFI 64 bit system table pointer.
+    SMBIOS,                 ///< Contains copy of all Sytem Management BIOS tables.
+    ACPI_OLD,               ///< Contains copy of RSDP as defined per ACPI1.0 specification.
+    ACPI_NEW,               ///< Contains copy of RSDP as defined per ACPI2.0 or later specification.
+    NETWORK,                ///< Contains network information specified specified as DHCP.
+    EFI_MEMORY_MAP,         ///< Contains EFI memory map.
+    EFI_BS_NOT_TERMINATED,  ///< Indicated ExitBootServies wasn't called.
+    EFI32_IMAGE_HANDLE,     ///< EFI 32 bit image handle pointer.
+    EFI64_IMAGE_HANDLE,     ///< EFI 64 bit imae handle pointer.
+    LOAD_BASE_ADDRESS       ///< Contains image load base physical address.
+  };
+
+  /**
+   * @brief Header tag IDs.
+   */
+  enum struct tag_id : std::uint32_t
+  {
+    END,
+    INFORMATION_REQUEST,
+    ADDRESSES,
+    ENTRY_ADDRESS,
+    CONSOLE_FLAGS,
+    PREFERRED_FRAMEBUFFER_MODE,
+    PAGE_ALIGN_MODULES,
+    EFI_BOOT_SERVICES_SUPPORTED,
+    EFI32_ENTRY_ADDRESS,
+    EFI64_ENTRY_ADDRESS,
+    RELOCATABLE,
+  };
+
+  /**
+   * @brief System architecture IDs.
+   */
+  enum struct architecture_id : std::uint32_t
+  {
+    I386 = 0,
+    MIPS32 = 4,
+  };
+
+  /**
+   * @brief Memory type IDs.
+   */
+  enum struct memory_type : std::uint32_t
+  {
+    AVAILABLE = 1,
+    RESERVED,
+    ACPI_RECLAIMABLE,
+    NON_VOLATILE_STORAGE,
+    BAD_RAM,
+  };
+
+}  // namespace multiboot2::impl
+
+#endif
\ No newline at end of file
diff --git a/libs/multiboot2/include/multiboot2/impl/iterator.hpp b/libs/multiboot2/include/multiboot2/impl/iterator.hpp
new file mode 100644
index 0000000..b84ef2c
--- /dev/null
+++ b/libs/multiboot2/include/multiboot2/impl/iterator.hpp
@@ -0,0 +1,63 @@
+#ifndef MULTIBOOT2_IMPL_INFORMATION_ITERATOR_HPP
+#define MULTIBOOT2_IMPL_INFORMATION_ITERATOR_HPP
+
+#include "multiboot2/impl/ids.hpp"
+#include "multiboot2/impl/tag.hpp"
+
+#include <cstddef>
+#include <iterator>
+#include <optional>
+
+namespace multiboot2::impl
+{
+
+  struct information_iterator
+  {
+    using iterator_category = std::forward_iterator_tag;
+    using value_type = impl::tag_header;
+    using pointer = value_type const *;
+    using reference = value_type const &;
+    using difference_type = std::ptrdiff_t;
+
+    constexpr information_iterator() = default;
+
+    constexpr explicit information_iterator(impl::tag_header const * offset)
+        : m_current(offset)
+    {
+    }
+
+    auto constexpr operator==(information_iterator const &) const noexcept -> bool = default;
+
+    auto constexpr operator*() const noexcept -> reference { return *(m_current.value()); }
+
+    auto constexpr operator->() const noexcept -> pointer { return m_current.value(); }
+
+    auto constexpr operator++() noexcept -> information_iterator &
+    {
+      if (m_current)
+      {
+        if (auto next = m_current.value()->next(); next->information_id() != information_id::END)
+        {
+          m_current = next;
+        }
+        m_current.reset();
+      }
+      return *this;
+    }
+
+    auto constexpr operator++(int) noexcept -> information_iterator
+    {
+      auto copy = *this;
+      ++(*this);
+      return copy;
+    }
+
+  private:
+    std::optional<impl::tag_header const *> m_current{};
+  };
+
+  static_assert(std::input_or_output_iterator<information_iterator>);
+
+}  // namespace multiboot2::impl
+
+#endif
\ No newline at end of file
diff --git a/libs/multiboot2/include/multiboot2/impl/tag.hpp b/libs/multiboot2/include/multiboot2/impl/tag.hpp
new file mode 100644
index 0000000..f7471a4
--- /dev/null
+++ b/libs/multiboot2/include/multiboot2/impl/tag.hpp
@@ -0,0 +1,113 @@
+#ifndef MULTIBOOT2_IMPL_TAG_HPP
+#define MULTIBOOT2_IMPL_TAG_HPP
+
+#include "multiboot2/impl/ids.hpp"
+
+#include <bit>
+#include <cstddef>
+#include <string_view>
+
+namespace multiboot2::impl
+{
+
+  /**
+   * @brief Header data and functionality shared by all tags.
+   */
+  struct tag_header
+  {
+    tag_header()
+        : m_id{}
+        , m_size{}
+    {
+    }
+
+    tag_header(tag_header const * data)
+        : tag_header{*data}
+    {
+    }
+
+    auto full_size() const noexcept -> std::size_t { return (m_size + 7) & (~7); }
+
+    auto information_id() const noexcept -> impl::information_id const & { return m_id; }
+
+    auto next() const noexcept -> tag_header const *
+    {
+      return std::bit_cast<tag_header const *>(std::bit_cast<std::byte const *>(this) + full_size());
+    }
+
+    auto unaligned_size() const noexcept -> std::uint32_t { return m_size; }
+
+  protected:
+    impl::information_id const m_id;
+    std::uint32_t const m_size;
+  };
+
+  /**
+   * @brief A tag containing no variable length array data.
+   */
+  template<typename Data>
+  struct tag : tag_header, Data
+  {
+    tag()
+        : tag_header{}
+        , Data{}
+    {
+    }
+
+    explicit tag(tag_header const * header)
+      requires(sizeof(tag) > sizeof(tag_header))
+        : tag_header{header}
+        , Data{*std::bit_cast<Data const *>(header + 1)}
+    {
+    }
+
+    explicit tag(tag_header const * header)
+      requires(sizeof(tag) == sizeof(tag_header))
+        : tag_header{header}
+        , Data{}
+    {
+    }
+  };
+
+  /**
+   * @brief A tag containing variable length array data.
+   */
+  template<typename Data, typename VlaData, template<typename> typename Range>
+  struct vla_tag : tag<Data>
+  {
+    using range_type = Range<VlaData>;
+
+    vla_tag()
+        : tag<Data>{}
+        , m_vla{}
+    {
+    }
+
+    explicit vla_tag(tag_header const * header)
+        : tag<Data>{header}
+        , m_vla{vla_start(header), vla_size(header)}
+    {
+    }
+
+  protected:
+    auto static vla_start(tag_header const * header) noexcept -> VlaData *
+    {
+      auto raw = std::bit_cast<std::byte const *>(header);
+      auto start = raw + sizeof(tag<Data>);
+      return std::bit_cast<VlaData *>(start);
+    }
+
+    auto static vla_size(tag_header const * header) noexcept -> std::size_t
+    {
+      auto size = (header->unaligned_size() - sizeof(tag<Data>) -
+                   std::is_same_v<range_type, std::basic_string_view<VlaData>> * 1) /
+                  sizeof(VlaData);
+      return size;
+    }
+
+    range_type const m_vla;
+  };
+
+}  // namespace multiboot2::impl
+
+#endif
\ No newline at end of file
diff --git a/libs/multiboot2/include/multiboot2/information.hpp b/libs/multiboot2/include/multiboot2/information.hpp
new file mode 100644
index 0000000..04ba183
--- /dev/null
+++ b/libs/multiboot2/include/multiboot2/information.hpp
@@ -0,0 +1,160 @@
+#ifndef JOS_MULTIBOOT2_INFORMATION_HPP
+#define JOS_MULTIBOOT2_INFORMATION_HPP
+
+#include "impl/data.hpp"
+#include "impl/iterator.hpp"
+#include "impl/tag.hpp"
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <optional>
+#include <span>
+#include <string_view>
+
+namespace multiboot2
+{
+
+  /**
+   * @copydoc multiboot2::impl::basic_memory_data
+   */
+  struct basic_memory : impl::tag<impl::basic_memory_data>
+  {
+    using tag::tag;
+  };
+
+  /**
+   * @copydoc multiboot2::impl::bios_boot_device_data
+   */
+  struct bios_boot_device : impl::tag<impl::bios_boot_device_data>
+  {
+    using tag::tag;
+  };
+
+  /**
+   * @copydoc multiboot2::impl::command_line_data
+   */
+  struct command_line : impl::vla_tag<impl::command_line_data, char, std::basic_string_view>
+  {
+    using vla_tag::vla_tag;
+
+    /**
+     * @brief The command line string
+     */
+    auto string() const noexcept -> range_type { return m_vla; }
+  };
+
+  /**
+   * @copydoc multiboot2::impl::elf_symbols_data
+   */
+  struct elf_symbols : impl::vla_tag<impl::elf_symbols_data, std::byte const, std::span>
+  {
+    using vla_tag::vla_tag;
+
+    using iterator = range_type::iterator;
+
+    auto data() const noexcept -> range_type { return m_vla; }
+  };
+
+  /**
+   * @copydoc multiboot2::impl::loader_name_data
+   */
+  struct loader_name : impl::vla_tag<impl::loader_name_data, char, std::basic_string_view>
+  {
+    using vla_tag::vla_tag;
+
+    /**
+     * @brief The name of the bootloader
+     */
+    auto string() const noexcept -> std::string_view { return m_vla; }
+  };
+
+  /**
+   * @copydoc multiboot2::impl::memory_map_data
+   */
+  struct memory_map : impl::vla_tag<impl::memory_map_data, impl::memory_map_data::region, std::span>
+  {
+    using vla_tag::vla_tag;
+
+    using iterator = range_type::iterator;
+
+    auto begin() const noexcept -> iterator { return regions().begin(); }
+
+    auto end() const noexcept -> iterator { return regions().end(); }
+
+    /**
+     * @brief The available memory regions
+     */
+    auto regions() const noexcept -> range_type { return m_vla; }
+  };
+
+  struct information_view
+  {
+    using iterator = impl::information_iterator;
+    using value_type = impl::information_iterator::value_type;
+    using pointer = impl::information_iterator::pointer;
+    using reference = impl::information_iterator::reference;
+
+    auto size_bytes() const noexcept -> std::size_t { return m_size; }
+
+    // Range access
+
+    auto begin() const noexcept -> iterator { return iterator{&m_tags}; }
+
+    auto end() const noexcept -> iterator { return iterator{}; }
+
+    // Tag access
+
+    template<typename Tag>
+    auto has() const noexcept -> bool
+    {
+      return get<Tag>().has_value();
+    }
+
+    auto maybe_basic_memory() const noexcept -> std::optional<basic_memory> { return get<multiboot2::basic_memory>(); }
+
+    auto basic_memory() const -> basic_memory { return maybe_basic_memory().value(); }
+
+    auto maybe_bios_boot_device() const noexcept -> std::optional<bios_boot_device>
+    {
+      return get<multiboot2::bios_boot_device>();
+    }
+
+    auto bios_boot_device() const -> bios_boot_device { return maybe_bios_boot_device().value(); }
+
+    auto maybe_command_line() const noexcept -> std::optional<command_line> { return get<multiboot2::command_line>(); }
+
+    auto command_line() const -> command_line { return maybe_command_line().value(); }
+
+    auto maybe_elf_symbols() const noexcept -> std::optional<elf_symbols> { return get<multiboot2::elf_symbols>(); }
+
+    auto elf_symbols() const -> elf_symbols { return maybe_elf_symbols().value(); }
+
+    auto maybe_loader_name() const noexcept -> std::optional<loader_name> { return get<multiboot2::loader_name>(); }
+
+    auto loader_name() const -> loader_name { return maybe_loader_name().value(); }
+
+    auto maybe_memory_map() const noexcept -> std::optional<memory_map> { return get<multiboot2::memory_map>(); }
+
+    auto memory_map() const -> memory_map { return maybe_memory_map().value(); }
+
+  private:
+    template<typename Tag>
+    auto constexpr get() const noexcept -> std::optional<Tag>
+    {
+      if (auto found = std::ranges::find_if(*this, [](auto tag) { return tag.information_id() == Tag::id; });
+          found != end())
+      {
+        return Tag{&*found};
+      }
+      return std::nullopt;
+    }
+
+    [[maybe_unused]] uint32_t const m_size{};
+    uint32_t : 32;
+    impl::tag_header const m_tags{};
+  };
+
+}  // namespace multiboot2
+
+#endif
\ No newline at end of file