ctypescrypto/bio.py

   1 from ctypescrypto import libcrypto
   2 from ctypes import c_char_p, c_void_p, c_int, string_at, c_long,POINTER,byref, create_string_buffer
   3 class Membio:
   4         """
   5                 Provides interface to OpenSSL memory bios
   6                 use str() to get contents of writable bio
   7                 use bio member to pass to libcrypto function
   8         """
   9         def __init__(self,data=None):
  10                 """ If data is specified, creates read-only BIO. If data is
  11                         None, creates writable BIO
  12                 """
  13                 if data is None:
  14                         method=libcrypto.BIO_s_mem()
  15                         self.bio=libcrypto.BIO_new(method)
  16                 else:
  17                         self.bio=libcrypto.BIO_new_mem_buf(c_char_p(data),len(data))
  18         def __del__(self):
  19                 libcrypto.BIO_free(self.bio)
  20                 del(self.bio)
  21         def __str__(self):
  22                 p=c_char_p(None)
  23                 l=libcrypto.BIO_ctrl(self.bio,3,0,byref(p))
  24                 return string_at(p,l)
  25         def read(self,length=None):
  26                 if not length is None:
  27                         if type(length)!=type(0):
  28                                 raise TypeError("length to read should be number")
  29                         buf=create_string_buffer(length)
  30                         readbytes=libcrypto.BIO_read(self.bio,buf,length)
  31                         if readbytes==-2:
  32                                 raise NotImplementedError("Function is not supported by this BIO")
  33                         if readbytes==-1:
  34                                 raise IOError
  35                         if readbytes==0:
  36                                 return ""
  37                         return buf.raw[:readbytes]
  38                 else:
  39                         buf=create_string_buffer(1024)
  40                         out=""
  41                         r=1
  42                         while r>0:
  43                                 r=libcrypto.BIO_read(self.bio,buf,1024)
  44                                 if r==-2:
  45                                         raise NotImplementedError("Function is not supported by this BIO")
  46                                 if r==-1:
  47                                         raise IOError
  48                                 if (r>0):
  49                                         out+=buf.raw[:r]
  50                         return out
  51
  52         def write(self,data):
  53                 r=libcrypto.BIO_write(self.bio,data,len(data))
  54                 if r==-2:
  55                         raise NotImplementedError("Function not supported by this BIO")
  56                 if r<len(data):
  57                         raise IOError("Not all data were successfully written")
  58
  59 #FIXME TODO - BIO should have stream-like interface
  60 libcrypto.BIO_s_mem.restype=c_void_p
  61 libcrypto.BIO_new.restype=c_void_p
  62 libcrypto.BIO_new.argtypes=(c_void_p,)
  63 libcrypto.BIO_ctrl.restype=c_long
  64 libcrypto.BIO_ctrl.argtypes=(c_void_p,c_int,c_long,POINTER(c_char_p))
  65 libcrypto.BIO_read.argtypes=(c_void_p,c_char_p,c_int)
  66 libcrypto.BIO_write.argtypes=(c_void_p,c_char_p,c_int)