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#include <iostream>
#include <cassert>
#include <algorithm>
#include <cstring>
#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() {
assert(shdr.empty());
shdr.resize(ehdr.e_shnum);
handle.seekg(ehdr.e_shoff);
handle.read((char*)shdr.data(), ehdr.e_shnum * ehdr.e_shentsize);
}
void Elf32File::ReadProgramHeaders() {
assert(phdr.empty());
phdr.resize(ehdr.e_phnum);
handle.seekg(ehdr.e_phoff);
handle.read((char*)phdr.data(), ehdr.e_phnum * ehdr.e_phentsize);
}
void Elf32File::ReadShstrtab() {
assert(shstrtab.empty());
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() {
assert(strtab.empty());
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() {
assert(symtab.empty());
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, elfload load) {
open(filename, load);
}
void Elf32File::open(path const& filename, elfload load) {
assert(!is_open());
handle.open(filename, ios::binary);
assert(handle.good());
ReadElfHeaderAndVerify();
if (load & sections) {
ReadSectionHeaders();
ReadShstrtab();
}
if (load & programs) {
ReadProgramHeaders();
}
if (load & symbols) {
assert(load & sections);
ReadStrtab();
ReadSymtab();
}
}
void Elf32File::close() {
if (is_open()) {
handle.close();
}
memset(&ehdr, 0, sizeof(ehdr));
shdr.clear();
symtab.clear();
phdr.clear();
shstrtab.clear();
strtab.clear();
}
bool Elf32File::is_open() const {
return handle.is_open();
}
Elf32File::~Elf32File() {
close();
}
vector<Elf32_Shdr> &Elf32File::GetSectionHeaders() {
return shdr;
}
vector<Elf32_Phdr> &Elf32File::GetProgramHeaders() {
return phdr;
}
string Elf32File::GetSectionName(const Elf32_Shdr §ion) 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::operator[](const string &name) {
return *find_if(symtab.begin(), symtab.end(), [&](Elf32_Sym const &sym) { return name == GetSymbolName(sym); });
}
Elf32_Sym &Elf32File::at(const string &name) {
auto ret = find_if(symtab.begin(), symtab.end(), [&](Elf32_Sym const &sym) { return name == GetSymbolName(sym); });
if (ret == symtab.end()) {
throw runtime_error("no symbol named " + name);
}
return *ret;
}
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