From ee18ec019ef6f0ef9d7cd3b4cf0314291814cab0 Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Sat, 28 Mar 2020 22:27:01 +0100
Subject: Add ELF handling (WIP)

---
 elf.cpp | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)

(limited to 'elf.cpp')

diff --git a/elf.cpp b/elf.cpp
index c94f2f5..9a835ff 100644
--- a/elf.cpp
+++ b/elf.cpp
@@ -1 +1,90 @@
 #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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