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#include "elf.h"
#include "file.h"
//#include <boost/endian/conversion.hpp>
#include <cstring>
// Helper Functions
namespace {
void AddFileHeader(std::vector<uint8_t>& data, const std::vector<uint8_t>& code)
{
Elf::FileHeader fh;
fh.e_shoff = sizeof(fh) + sizeof(Elf::ProgramHeader) + code.size() + 16;
size_t old_size {data.size()};
data.resize(old_size + sizeof(fh));
std::memcpy(data.data() + old_size, reinterpret_cast<void*>(&fh), sizeof(fh));
}
void AddProgramHeader(std::vector<uint8_t>& data, const std::vector<uint8_t>& code)
{
Elf::ProgramHeader ph;
ph.p_offset = sizeof(Elf::FileHeader) + sizeof(Elf::ProgramHeader);
ph.p_filesz = code.size();
ph.p_memsz = code.size();
size_t old_size {data.size()};
data.resize(old_size + sizeof(ph));
std::memcpy(data.data() + old_size, reinterpret_cast<void*>(&ph), sizeof(ph));
}
void AddSectionHeaderText(std::vector<uint8_t>& data, const std::vector<uint8_t>& code)
{
Elf::SectionHeader sh;
sh.sh_name = 0; // offset in section
sh.sh_size = code.size();
sh.sh_type = 1; // program
size_t old_size {data.size()};
data.resize(old_size + sizeof(sh));
std::memcpy(data.data() + old_size, reinterpret_cast<void*>(&sh), sizeof(sh));
}
void AddSectionHeaderSectionNames(std::vector<uint8_t>& data, const std::vector<uint8_t>& code)
{
Elf::SectionHeader sh;
sh.sh_name = 0; // offset in section
sh.sh_size = 16;
sh.sh_type = 3; // section names
sh.sh_flags = 0;
size_t old_size {data.size()};
data.resize(old_size + sizeof(sh));
std::memcpy(data.data() + old_size, reinterpret_cast<void*>(&sh), sizeof(sh));
}
}
void Elf::Write(const std::filesystem::path& path, const std::vector<uint8_t>& code)
{
std::vector<uint8_t> data;
AddFileHeader(data, code);
AddProgramHeader(data, code);
data.insert(data.end(), code.begin(), code.end());
std::string section_names(".text\0.shstrtab\0", 16);
size_t old_size {data.size()};
data.resize(old_size + section_names.size());
std::memcpy(data.data() + old_size, section_names.data(), section_names.size());
AddSectionHeaderText(data, code);
AddSectionHeaderSectionNames(data, code);
File::setFile(path, data);
}
std::vector<uint8_t> Elf::Read(const std::filesystem::path& path)
{
std::vector<uint8_t> result;
// TODO
return result;
}
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