pokeheartgold/.github/calcrom/ElfFile.cpp
2021-11-10 20:19:24 -05:00

106 lines
2.9 KiB
C++

#include <iostream>
#include <cassert>
#include <algorithm>
#include "ElfFile.h"
void Elf32File::ReadElfHeaderAndVerify() {
handle.seekg(0);
handle.read((char *)ehdr.e_ident, EI_NIDENT);
assert(memcmp(ehdr.e_ident, ELFMAG, SELFMAG) == 0);
assert(ehdr.e_ident[EI_CLASS] == ELFCLASS32);
assert(ehdr.e_ident[EI_DATA] == ELFDATA2LSB);
assert(ehdr.e_ident[EI_VERSION] == EV_CURRENT);
handle.read((char*)&ehdr + EI_NIDENT, sizeof(ehdr) - EI_NIDENT);
assert(ehdr.e_shentsize == sizeof(Elf32_Shdr));
}
void Elf32File::ReadSectionHeaders() {
shdr.resize(ehdr.e_shnum);
handle.seekg(ehdr.e_shoff);
handle.read((char*)shdr.data(), ehdr.e_shnum * ehdr.e_shentsize);
}
void Elf32File::ReadShstrtab() {
shstrtab.resize(shdr[ehdr.e_shstrndx].sh_size);
handle.seekg(shdr[ehdr.e_shstrndx].sh_offset);
handle.read((char*)shstrtab.data(), shdr[ehdr.e_shstrndx].sh_size);
}
void Elf32File::ReadStrtab() {
int i;
for (i = 1; i < ehdr.e_shnum; i++) {
if (i == ehdr.e_shstrndx) continue;
if (shdr[i].sh_type == SHT_STRTAB) break;
}
assert(i != ehdr.e_shnum);
strtab.resize(shdr[i].sh_size);
handle.seekg(shdr[i].sh_offset);
handle.read((char*)strtab.data(), shdr[i].sh_size);
}
void Elf32File::ReadSymtab() {
auto sec = find_if(shdr.begin(), shdr.end(), [](Elf32_Shdr const& candidate) { return candidate.sh_type == SHT_SYMTAB; });
assert(sec != shdr.end());
symtab.resize(sec->sh_size);
handle.seekg(sec->sh_offset);
handle.read((char*)symtab.data(), sec->sh_size);
}
Elf32File::Elf32File(path const& filename, bool read_syms) : handle(filename, ios::binary) {
assert(handle.good());
ReadElfHeaderAndVerify();
ReadSectionHeaders();
ReadShstrtab();
if (read_syms) {
ReadStrtab();
ReadSymtab();
}
}
Elf32File::~Elf32File() {
handle.close();
}
vector<Elf32_Shdr> &Elf32File::GetSectionHeaders() {
return shdr;
}
string Elf32File::GetSectionName(const Elf32_Shdr &section) const {
return string(shstrtab.data() + section.sh_name);
}
string Elf32File::GetSymbolName(const Elf32_Sym &symbol) const {
return string(strtab.data() + symbol.st_name);
}
Elf32_Sym &Elf32File::FindSymbol(const string &name) {
for (Elf32_Sym &sym : symtab) {
cerr << GetSymbolName(sym) << endl;
if (name == GetSymbolName(sym)) {
return sym;
}
}
return *symtab.end();
}
Elf32_Sym &Elf32File::operator[](const string &name) {
sym_iterator ret;
for (ret = symtab.begin(); ret != symtab.end(); ret++) {
if (name == GetSymbolName(*ret)) {
break;
}
}
return *ret;
}
Elf32_Sym &Elf32File::at(const string &name) {
sym_iterator ret;
for (ret = symtab.begin(); ret != symtab.end(); ret++) {
if (name == GetSymbolName(*ret)) {
break;
}
}
if (ret == symtab.end()) {
throw runtime_error("no symbol named " + name);
}
return *ret;
}