ctypescrypto/bio.py

   1 """
   2 Interface to OpenSSL BIO library
   3 """
   4 from ctypescrypto import libcrypto
   5 from ctypes import c_char_p, c_void_p, c_int, string_at, c_long,POINTER,byref, create_string_buffer
   6 class Membio(object):
   7     """
   8         Provides interface to OpenSSL memory bios
   9         use str() or unicode() to get contents of writable bio
  10         use bio member to pass to libcrypto function
  11     """
  12     def __init__(self,data=None):
  13         """ If data is specified, creates read-only BIO. If data is
  14             None, creates writable BIO, contents of which can be retrieved by str() or unicode()
  15         """
  16         if data is None:
  17             method=libcrypto.BIO_s_mem()
  18             self.bio=libcrypto.BIO_new(method)
  19         else:
  20             self.bio=libcrypto.BIO_new_mem_buf(c_char_p(data),len(data))
  21     def __del__(self):
  22         """
  23         Cleans up memory used by bio
  24         """
  25         libcrypto.BIO_free(self.bio)
  26         del(self.bio)
  27     def __str__(self):
  28         """
  29         Returns current contents of buffer as byte string
  30         """
  31         p=c_char_p(None)
  32         l=libcrypto.BIO_ctrl(self.bio,3,0,byref(p))
  33         return string_at(p,l)
  34     def __unicode__(self):
  35         """
  36         Attempts to interpret current contents of buffer as UTF-8 string and convert it to unicode
  37         """
  38         return str(self).decode("utf-8")
  39     def read(self,length=None):
  40         """
  41         Reads data from readble BIO. For test purposes.
  42         @param length - if specifed, limits amount of data read. If not BIO is read until end of buffer
  43         """
  44         if not length is None:
  45             if not isinstance(length,(int,long)):
  46                 raise TypeError("length to read should be number")
  47             buf=create_string_buffer(length)
  48             readbytes=libcrypto.BIO_read(self.bio,buf,length)
  49             if readbytes==-2:
  50                 raise NotImplementedError("Function is not supported by this BIO")
  51             if readbytes==-1:
  52                 raise IOError
  53             if readbytes==0:
  54                 return ""
  55             return buf.raw[:readbytes]
  56         else:
  57             buf=create_string_buffer(1024)
  58             out=""
  59             r=1
  60             while r>0:
  61                 r=libcrypto.BIO_read(self.bio,buf,1024)
  62                 if r==-2:
  63                     raise NotImplementedError("Function is not supported by this BIO")
  64                 if r==-1:
  65                     raise IOError
  66                 if (r>0):
  67                     out+=buf.raw[:r]
  68             return out
  69
  70     def write(self,data):
  71         """
  72         Writes data to writable bio. For test purposes
  73         """
  74         if isinstance(data,unicode):
  75             data=data.encode("utf-8")
  76         r=libcrypto.BIO_write(self.bio,data,len(data))
  77         if r==-2:
  78             raise NotImplementedError("Function not supported by this BIO")
  79         if r<len(data):
  80             raise IOError("Not all data were successfully written")
  81     def reset(self):
  82         """
  83         Resets the read-only bio to start and discards all data from writable bio
  84         """
  85         libcrypto.BIO_ctrl(self.bio,1,0,None)
  86
  87 __all__ = ['Membio']
  88 libcrypto.BIO_s_mem.restype=c_void_p
  89 libcrypto.BIO_new.restype=c_void_p
  90 libcrypto.BIO_new.argtypes=(c_void_p,)
  91 libcrypto.BIO_ctrl.restype=c_long
  92 libcrypto.BIO_ctrl.argtypes=(c_void_p,c_int,c_long,POINTER(c_char_p))
  93 libcrypto.BIO_read.argtypes=(c_void_p,c_char_p,c_int)
  94 libcrypto.BIO_write.argtypes=(c_void_p,c_char_p,c_int)
  95 libcrypto.BIO_free.argtypes=(c_void_p,)
  96 libcrypto.BIO_new_mem_buf.restype=c_void_p
  97 libcrypto.BIO_new_mem_buf.argtypes=(c_char_p,c_int)
  98 libcrypto.BIO_ctrl.argtypes=(c_void_p,c_int,c_int,c_void_p)