使用pefile module顯示執行檔案所需要的DLL

最近才發現原來Python有一個可以讀取Portable Executable格式的module pefile[1]。於是就拿來練習，寫了一個可以顯示執行檔所需要的DLL的小程式。

    #!/usr/bin/env python
    # coding: utf-8
    """ showdll.py: show the depedency of given exeutable file. """
    
    import sys
    from os import path
    
    import pefile
    
    def get_depend(filename, dll_list=[]):
        """Return the dependency in hierarchical dictionary."""
        if not path.isfile(filename):
            return 
        pe_obj = pefile.PE(filename, fast_load=True)
        pe_obj.parse_data_directories()
        dlls = {}    
        if hasattr(pe_obj, 'DIRECTORY_ENTRY_IMPORT'):
            curr_dependency = []
            for entry in pe_obj.DIRECTORY_ENTRY_IMPORT:
                if entry.dll not in dll_list:
                    dll_list.append(entry.dll)
                    curr_dependency.append(entry.dll)
            for entry in curr_dependency:
                dlls[entry] = get_depend(entry, dll_list)
        return dlls
    
    def print_depend(dependency, depth=0, padding='\t'):
        prepend = padding * depth
        for k,v in dependency.items():
            print "%s%s" % (prepend, k)
            if isinstance(v, dict):
                print_depend(v, depth+1, padding)
    
    if __name__ == '__main__':
        dependency = get_depend(sys.argv[1])
        print_depend(dependency)

Usage:

    > showdll.py foo.exe

[1]: https://code.google.com/p/pefile/