ctypescrypto/engine.py

   1 """
   2 engine loading and configuration
   3 """
   4 from ctypes import c_void_p, c_char_p, c_int
   5 from ctypescrypto import libcrypto
   6 from ctypescrypto.exception import LibCryptoError
   7
   8 __all__ = ['default', 'set_default']
   9
  10 default = None
  11
  12 def set_default(engine):
  13     """
  14     Loads specified engine and sets it as default for all
  15     algorithms, supported by it
  16     """
  17     global default
  18     eng = libcrypto.ENGINE_by_id(engine)
  19     if eng is None:
  20         # Try load engine
  21         eng = libcrypto.ENGINE_by_id("dynamic")
  22         if  eng is None:
  23             raise LibCryptoError("Cannot get 'dynamic' engine")
  24         if not libcrypto.ENGINE_ctrl_cmd_string(eng, "SO_PATH", engine, 0):
  25             raise LibCryptoError("Cannot execute ctrl cmd SO_PATH")
  26         if not libcrypto.ENGINE_ctrl_cmd_string(eng, "LOAD", None, 0):
  27             raise LibCryptoError("Cannot execute ctrl cmd LOAD")
  28     if eng is None:
  29         raise ValueError("Cannot find engine " + engine)
  30     libcrypto.ENGINE_set_default(eng, c_int(0xFFFF))
  31     default = eng
  32
  33 # Declare function result and arguments for used functions
  34 libcrypto.ENGINE_by_id.restype = c_void_p
  35 libcrypto.ENGINE_by_id.argtypes = (c_char_p, )
  36 libcrypto.ENGINE_set_default.argtypes = (c_void_p, c_int)
  37 libcrypto.ENGINE_ctrl_cmd_string.argtypes = (c_void_p, c_char_p, c_char_p,
  38                                              c_int)
  39 libcrypto.ENGINE_finish.argtypes = (c_char_p, )