Bootloader: Start work on bootloader

I wrote a fast first stage bootloader and a installer to put it into
a disk image.

bootloader/installer/ELF.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <cstdint>
+#include <optional>
+#include <span>
+#include <string_view>
+#include <string>
+#include <sys/stat.h>
+
+#include <elf.h>
+
+class ELFFile
+{
+public:
+	ELFFile(std::string_view path);
+	~ELFFile();
+
+	const Elf64_Ehdr& elf_header() const;
+	std::optional<std::span<const uint8_t>> find_section(std::string_view name) const;
+
+	bool success() const { return m_success; }
+
+	std::string_view path() const { return m_path; }
+
+private:
+	const Elf64_Shdr& section_header(std::size_t index) const;
+	std::string_view section_name(const Elf64_Shdr&) const;
+	bool validate_elf_header() const;
+
+private:
+	const std::string	m_path;
+	bool				m_success	{ false };
+	int					m_fd		{ -1 };
+	struct stat			m_stat		{ };
+	uint8_t*			m_mmap		{ nullptr };
+};