C++ ELFObjectFile类代码示例

void symbol_entries(const ELFObjectFile<T> &obj, ogre_doc &s) {
    typedef typename ELFFile<T>::Elf_Shdr sec_hdr;
    auto elf = obj.getELFFile();
    symbol_entries(obj, obj.symbol_begin(), obj.symbol_end(), s);
    auto secs = prim::elf_sections(*elf);
    bool is_dyn = std::any_of(secs.begin(), secs.end(),
                              [](const sec_hdr &hdr) { return (hdr.sh_type == ELF::SHT_DYNSYM); });
    if (is_dyn) // preventing from llvm 3.8 fail in case of .dynsym absence
        symbol_entries(obj, obj.dynamic_symbol_begin(), obj.dynamic_symbol_end(), s);
}

bool checked(const ELFObjectFile<T> &obj, SectionRef sec_ref) {
    typedef typename ELFObjectFile<T>::Elf_Shdr Elf_Shdr;

    auto &elf = *obj.getELFFile();
    const Elf_Shdr *RelSec = obj.getSection(sec_ref.getRawDataRefImpl());
    auto symsec = elf.getSection(RelSec->sh_link);
    if (!symsec) return false;
    uint32_t sec_typ = (*symsec)->sh_type;
    return
        (sec_typ == ELF::SHT_SYMTAB || sec_typ == ELF::SHT_DYNSYM);
}

uint64_t section_offset(const ELFObjectFile<T> &obj, section_iterator it) {
    typedef typename ELFObjectFile<T>::Elf_Shdr_Iter elf_shdr_iterator;

    if (it == obj.end_sections()) return 0; // check for special elf sections

    auto elf = obj.getELFFile();
    auto raw = it->getRawDataRefImpl();
    auto elf_sec_it = elf_shdr_iterator(elf->getHeader()->e_shentsize,
                                        reinterpret_cast<const char *>(raw.p));
    return elf_sec_it->sh_offset;
}

std::vector<segment> read(const ELFObjectFile<T>& obj) {
    auto begin = obj.getELFFile()->begin_program_headers();
    auto end = obj.getELFFile()->end_program_headers();
    std::vector<segment> segments;
    segments.reserve(std::distance(begin, end));
    for (int pos = 0; begin != end; ++begin, ++pos) {
        if (begin -> p_type == ELF::PT_LOAD) {
            segments.push_back(segment(*begin, pos));
        }
    }
    return segments;
}

static bool isObject(ELFObjectFile<ELFT> &Obj, symbol_iterator I) {
  typedef typename ELFObjectFile<ELFT>::Elf_Sym Elf_Sym;

  DataRefImpl Symb = I->getRawDataRefImpl();
  const Elf_Sym *ESym = Obj.getSymbol(Symb);

  return ESym->getType() == ELF::STT_OBJECT;
}

void relocations(const ELFObjectFile<T> &obj, ogre_doc &s) {
    for (auto sec : obj.sections()) {
        auto rel_sec = sec.getRelocatedSection();
        if (!checked(obj, sec)) continue;
        for (auto rel : sec.relocations())
            symbol_reference(obj, rel, rel_sec, s);
    }
}

static char getSymbolNMTypeChar(ELFObjectFile<ELFT> &Obj,
                                basic_symbol_iterator I) {
  typedef typename ELFObjectFile<ELFT>::Elf_Sym Elf_Sym;
  typedef typename ELFObjectFile<ELFT>::Elf_Shdr Elf_Shdr;

  // OK, this is ELF
  symbol_iterator SymI(I);

  DataRefImpl Symb = I->getRawDataRefImpl();
  const Elf_Sym *ESym = Obj.getSymbol(Symb);
  const ELFFile<ELFT> &EF = *Obj.getELFFile();
  const Elf_Shdr *ESec = EF.getSection(ESym);

  if (ESec) {
    switch (ESec->sh_type) {
    case ELF::SHT_PROGBITS:
    case ELF::SHT_DYNAMIC:
      switch (ESec->sh_flags) {
      case (ELF::SHF_ALLOC | ELF::SHF_EXECINSTR):
        return 't';
      case (ELF::SHF_TLS | ELF::SHF_ALLOC | ELF::SHF_WRITE):
      case (ELF::SHF_ALLOC | ELF::SHF_WRITE):
        return 'd';
      case ELF::SHF_ALLOC:
      case (ELF::SHF_ALLOC | ELF::SHF_MERGE):
      case (ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::SHF_STRINGS):
        return 'r';
      }
      break;
    case ELF::SHT_NOBITS:
      return 'b';
    }
  }

  if (ESym->getType() == ELF::STT_SECTION) {
    StringRef Name;
    if (error(SymI->getName(Name)))
      return '?';
    return StringSwitch<char>(Name)
        .StartsWith(".debug", 'N')
        .StartsWith(".note", 'n')
        .Default('?');
  }

  return '?';
}

void section_headers(const ELFObjectFile<T> &obj, ogre_doc &s) {
    auto elf = obj.getELFFile();
    auto base = base_address(obj);
    for (auto sec : prim::elf_sections(*elf)) {
        auto name = prim::elf_section_name(*elf, &sec);
        if (name)
            section_header(sec, *name, base, s);
    }
}

error_or<int64_t> symbol_address(const ELFObjectFile<T> &obj, const SymbolRef &sym) {
    auto sym_elf = obj.getSymbol(sym.getRawDataRefImpl());
    if (is_rel(obj) && !is_abs_symbol(*sym_elf)) { // abs symbols does not affected by relocations
        return success(int64_t(0));
    } else {
        auto addr = prim::symbol_address(sym);
        if (!addr) return addr;
        auto base = base_address(obj);
        return success(prim::relative_address(base, *addr));
    }
}

error_or<symbol_sizes> getSymbolSizes(const ELFObjectFile<ELFT> &obj) {
    typedef typename ELFFile<ELFT>::Elf_Shdr sec_hdr;

    symbol_sizes syms;
    for (auto sym : obj.symbols())
        syms.push_back({sym, sym.getSize()});

    auto sections = prim::elf_sections(*obj.getELFFile());
    bool is_dyn = std::any_of(sections.begin(), sections.end(),
                              [](const sec_hdr &hdr) { return (hdr.sh_type == ELF::SHT_DYNSYM); });

    if (!syms.size() && !is_dyn)
        return success(symbol_sizes());

    if (is_dyn)  // we aren't able to rely on iterators because of bug in llvm
        for (auto sym : obj.getDynamicSymbolIterators())
            syms.push_back({sym, sym.getSize()});

    return success(syms);
}

void symbol_entry(const ELFObjectFile<T> &obj, const SymbolRef &sym, ogre_doc &s) {
    auto sym_elf = obj.getSymbol(sym.getRawDataRefImpl());
    if (is_abs_symbol(*sym_elf)) {
        return;
    }
    auto name = prim::symbol_name(sym);
    auto addr = symbol_address(obj, sym);
    auto off = symbol_file_offset(obj, sym);
    if (name && addr && off) {
        s.entry("symbol-entry") << *name << *addr << sym_elf->st_size << *off;
        if (sym_elf->getType() == ELF::STT_FUNC)
            s.entry("code-entry") << *name << *off << sym_elf->st_size ;
    }
}

void symbol_reference(const ELFObjectFile<T> &obj, const RelocationRef &rel, section_iterator sec, ogre_doc &s) {
    auto it = rel.getSymbol();
    if (it == prim::end_symbols(obj)) return;
    auto sym_elf = obj.getSymbol(it->getRawDataRefImpl());
    auto sec_offset = section_offset(obj, sec);
    auto off = prim::relocation_offset(rel) + sec_offset; // relocation file offset
    if (is_external_symbol(*sym_elf)) {
        if (auto name = prim::symbol_name(*it))
            s.entry("ref-external") << off << *name;
    } else {
        if (auto file_offset = symbol_file_offset(obj, *it))
            s.entry("ref-internal") << *file_offset << off;
    }
}

void program_headers(const ELFObjectFile<T> &obj, ogre_doc &s) {
    auto elf = obj.getELFFile();
    program_headers(elf->begin_program_headers(), elf->end_program_headers(), s);
}

uint64_t base_address(const ELFObjectFile<T> &obj) {
    auto elf = obj.getELFFile();
    return base_address(elf->begin_program_headers(), elf->end_program_headers());
}

bool is_rel(const ELFObjectFile<T> &obj) {
    auto hdr = obj.getELFFile()->getHeader();
    return (hdr->e_type == ELF::ET_REL);
}