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)