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() or unicode() 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, contents of which can be retrieved by str() or unicode()
  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                 """
  20                 Cleans up memory used by bio
  21                 """
  22                 libcrypto.BIO_free(self.bio)
  23                 del(self.bio)
  24         def __str__(self):
  25                 """
  26                 Returns current contents of buffer as byte string
  27                 """
  28                 p=c_char_p(None)
  29                 l=libcrypto.BIO_ctrl(self.bio,3,0,byref(p))
  30                 return string_at(p,l)
  31         def __unicode__(self):
  32                 """
  33                 Attempts to interpret current contents of buffer as UTF-8 string and convert it to unicode
  34                 """
  35                 return str(self).decode("utf-8")
  36         def read(self,length=None):
  37                 """
  38                 Reads data from readble BIO. For test purposes.
  39                 @param length - if specifed, limits amount of data read. If not BIO is read until end of buffer
  40                 """
  41                 if not length is None:
  42                         if type(length)!=type(0):
  43                                 raise TypeError("length to read should be number")
  44                         buf=create_string_buffer(length)
  45                         readbytes=libcrypto.BIO_read(self.bio,buf,length)
  46                         if readbytes==-2:
  47                                 raise NotImplementedError("Function is not supported by this BIO")
  48                         if readbytes==-1:
  49                                 raise IOError
  50                         if readbytes==0:
  51                                 return ""
  52                         return buf.raw[:readbytes]
  53                 else:
  54                         buf=create_string_buffer(1024)
  55                         out=""
  56                         r=1
  57                         while r>0:
  58                                 r=libcrypto.BIO_read(self.bio,buf,1024)
  59                                 if r==-2:
  60                                         raise NotImplementedError("Function is not supported by this BIO")
  61                                 if r==-1:
  62                                         raise IOError
  63                                 if (r>0):
  64                                         out+=buf.raw[:r]
  65                         return out
  66
  67         def write(self,data):
  68                 """
  69                 Writes data to writable bio. For test purposes
  70                 """
  71                 if isinstance(data,unicode):
  72                         data=data.encode("utf-8")
  73                 r=libcrypto.BIO_write(self.bio,data,len(data))
  74                 if r==-2:
  75                         raise NotImplementedError("Function not supported by this BIO")
  76                 if r<len(data):
  77                         raise IOError("Not all data were successfully written")
  78         def reset(self):
  79                 """
  80                 Resets the read-only bio to start and discards all data from writable bio
  81                 """
  82                 libcrypto.BIO_ctrl(self.bio,1,0,None)
  83 libcrypto.BIO_s_mem.restype=c_void_p
  84 libcrypto.BIO_new.restype=c_void_p
  85 libcrypto.BIO_new.argtypes=(c_void_p,)
  86 libcrypto.BIO_ctrl.restype=c_long
  87 libcrypto.BIO_ctrl.argtypes=(c_void_p,c_int,c_long,POINTER(c_char_p))
  88 libcrypto.BIO_read.argtypes=(c_void_p,c_char_p,c_int)
  89 libcrypto.BIO_write.argtypes=(c_void_p,c_char_p,c_int)
  90 libcrypto.BIO_free.argtypes=(c_void_p,)
  91 libcrypto.BIO_new_mem_buf.restype=c_void_p
  92 libcrypto.BIO_new_mem_buf.argtypes=(c_char_p,c_int)
  93 libcrypto.BIO_ctrl.argtypes=(c_void_p,c_int,c_int,c_void_p)