Method InitializeModules

snapshot/linux/process_reader_linux.cc:424–562

}

void ProcessReaderLinux::InitializeModules() {
  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
  initialized_modules_ = true;

  AuxiliaryVector aux;
  if (!aux.Initialize(connection_)) {
    return;
  }

  LinuxVMAddress phdrs;
  if (!aux.GetValue(AT_PHDR, &phdrs)) {
    return;
  }

  ProcessMemoryRange range;
  if (!range.Initialize(Memory(), is_64_bit_)) {
    return;
  }

  // The strategy used for identifying loaded modules depends on ELF files
  // conventionally loading their header and program headers into memory.
  // Locating the correct module could fail if the headers aren't mapped, are
  // mapped at an unexpected location, or if there are other mappings
  // constructed to look like the ELF module being searched for.
  const MemoryMap::Mapping* exe_mapping = nullptr;
  std::unique_ptr<ElfImageReader> exe_reader;
  {
    const MemoryMap::Mapping* phdr_mapping = memory_map_.FindMapping(phdrs);
    if (!phdr_mapping) {
      return;
    }

    auto possible_mappings =
        memory_map_.FindFilePossibleMmapStarts(*phdr_mapping);
    const MemoryMap::Mapping* mapping = nullptr;
    while ((mapping = possible_mappings->Next())) {
      auto parsed_exe = std::make_unique<ElfImageReader>();
      if (parsed_exe->Initialize(
              range,
              mapping->range.Base(),
              /* verbose= */ possible_mappings->Count() == 0) &&
          parsed_exe->GetProgramHeaderTableAddress() == phdrs) {
        exe_mapping = mapping;
        exe_reader = std::move(parsed_exe);
        break;
      }
    }
    if (!exe_mapping) {
      LOG(ERROR) << "no exe mappings 0x" << std::hex
                 << phdr_mapping->range.Base();
      return;
    }
  }

  LinuxVMAddress debug_address;
  if (!exe_reader->GetDebugAddress(&debug_address)) {
    return;
  }