"""A library for integrating pyOpenSSL with CherryPy.

 The OpenSSL module must be importable for SSL functionality.

 You can obtain it from http://pyopenssl.sourceforge.net/

 To use this module, set CherryPyWSGIServer.ssl_adapter to an instance of

 SSLAdapter. There are two ways to use SSL:

 Method One

 ----------

  * ``ssl_adapter.context``: an instance of SSL.Context.

 If this is not None, it is assumed to be an SSL.Context instance,

 and will be passed to SSL.Connection on bind(). The developer is

 responsible for forming a valid Context object. This approach is

 to be preferred for more flexibility, e.g. if the cert and key are

 streams instead of files, or need decryption, or SSL.SSLv3_METHOD

 is desired instead of the default SSL.SSLv23_METHOD, etc. Consult

 the pyOpenSSL documentation for complete options.

 Method Two (shortcut)

 ---------------------

  * ``ssl_adapter.certificate``: the filename of the server SSL certificate.

  * ``ssl_adapter.private_key``: the filename of the server's private key file.

 Both are None by default. If ssl_adapter.context is None, but .private_key

 and .certificate are both given and valid, they will be read, and the

 context will be automatically created from them.

 """

 import socket

 import threading

 import time

 from cherrypy import wsgiserver

 try:

     from OpenSSL import SSL

     from OpenSSL import crypto

 except ImportError:

     SSL = None

 class SSL_fileobject(wsgiserver.CP_fileobject):

     """SSL file object attached to a socket object."""

     ssl_timeout = 3

     ssl_retry = .01

     def _safe_call(self, is_reader, call, *args, **kwargs):

         """Wrap the given call with SSL error-trapping.

         is_reader: if False EOF errors will be raised. If True, EOF errors

         will return "" (to emulate normal sockets).

         """

         start = time.time()

         while True:

             try:

                 return call(*args, **kwargs)

             except SSL.WantReadError:

                 # Sleep and try again. This is dangerous, because it means

                 # the rest of the stack has no way of differentiating

                 # between a "new handshake" error and "client dropped".

                 # Note this isn't an endless loop: there's a timeout below.

                 time.sleep(self.ssl_retry)

             except SSL.WantWriteError:

                 time.sleep(self.ssl_retry)

             except SSL.SysCallError, e:

                 if is_reader and e.args == (-1, 'Unexpected EOF'):

                     return ""

                 errnum = e.args[0]

                 if is_reader and errnum in wsgiserver.socket_errors_to_ignore:

                     return ""

                 raise socket.error(errnum)

             except SSL.Error, e:

                 if is_reader and e.args == (-1, 'Unexpected EOF'):

                     return ""

                 thirdarg = None

                 try:

                     thirdarg = e.args[0][0][2]

                 except IndexError:

                     pass

                 if thirdarg == 'http request':

                     # The client is talking HTTP to an HTTPS server.

                     raise wsgiserver.NoSSLError()

                 raise wsgiserver.FatalSSLAlert(*e.args)

             except:

                 raise

             if time.time() - start > self.ssl_timeout:

                 raise socket.timeout("timed out")

     def recv(self, *args, **kwargs):

         buf = []

         r = super(SSL_fileobject, self).recv

         while True:

             data = self._safe_call(True, r, *args, **kwargs)

             buf.append(data)

             p = self._sock.pending()

             if not p:

                 return "".join(buf)

     def sendall(self, *args, **kwargs):

         return self._safe_call(False, super(SSL_fileobject, self).sendall,

                                *args, **kwargs)

     def send(self, *args, **kwargs):

         return self._safe_call(False, super(SSL_fileobject, self).send,

                                *args, **kwargs)

 class SSLConnection:

     """A thread-safe wrapper for an SSL.Connection.

     ``*args``: the arguments to create the wrapped ``SSL.Connection(*args)``.

     """

     def __init__(self, *args):

         self._ssl_conn = SSL.Connection(*args)

         self._lock = threading.RLock()

     for f in ('get_context', 'pending', 'send', 'write', 'recv', 'read',

               'renegotiate', 'bind', 'listen', 'connect', 'accept',

               'setblocking', 'fileno', 'close', 'get_cipher_list',

               'getpeername', 'getsockname', 'getsockopt', 'setsockopt',

               'makefile', 'get_app_data', 'set_app_data', 'state_string',

               'sock_shutdown', 'get_peer_certificate', 'want_read',

               'want_write', 'set_connect_state', 'set_accept_state',

               'connect_ex', 'sendall', 'settimeout', 'gettimeout'):

         exec("""def %s(self, *args):

         self._lock.acquire()

         try:

             return self._ssl_conn.%s(*args)

         finally:

             self._lock.release()

 """ % (f, f))

     def shutdown(self, *args):

         self._lock.acquire()

         try:

             # pyOpenSSL.socket.shutdown takes no args

             return self._ssl_conn.shutdown()

         finally:

             self._lock.release()

 class pyOpenSSLAdapter(wsgiserver.SSLAdapter):

     """A wrapper for integrating pyOpenSSL with CherryPy."""

     context = None

     """An instance of SSL.Context."""

     certificate = None

     """The filename of the server SSL certificate."""

     private_key = None

     """The filename of the server's private key file."""

     certificate_chain = None

     """Optional. The filename of CA's intermediate certificate bundle.

     This is needed for cheaper "chained root" SSL certificates, and should be

     left as None if not required."""

     def __init__(self, certificate, private_key, certificate_chain=None):

         if SSL is None:

             raise ImportError("You must install pyOpenSSL to use HTTPS.")

         self.context = None

         self.certificate = certificate

         self.private_key = private_key

         self.certificate_chain = certificate_chain

         self._environ = None

     def bind(self, sock):

         """Wrap and return the given socket."""

         if self.context is None:

             self.context = self.get_context()

         conn = SSLConnection(self.context, sock)

         self._environ = self.get_environ()

         return conn

     def wrap(self, sock):

         """Wrap and return the given socket, plus WSGI environ entries."""

         return sock, self._environ.copy()

     def get_context(self):

         """Return an SSL.Context from self attributes."""

         # See http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/442473

         c = SSL.Context(SSL.SSLv23_METHOD)

         c.use_privatekey_file(self.private_key)

         if self.certificate_chain:

             c.load_verify_locations(self.certificate_chain)

         c.use_certificate_file(self.certificate)

         return c

     def get_environ(self):

         """Return WSGI environ entries to be merged into each request."""

         ssl_environ = {

             "HTTPS": "on",

             # pyOpenSSL doesn't provide access to any of these AFAICT

 ##            'SSL_PROTOCOL': 'SSLv2',

 ##            SSL_CIPHER 	string 	The cipher specification name

 ##            SSL_VERSION_INTERFACE 	string 	The mod_ssl program version

 ##            SSL_VERSION_LIBRARY 	string 	The OpenSSL program version

             }

         if self.certificate:

             # Server certificate attributes

             cert = open(self.certificate, 'rb').read()

             cert = crypto.load_certificate(crypto.FILETYPE_PEM, cert)

             ssl_environ.update({

                 'SSL_SERVER_M_VERSION': cert.get_version(),

                 'SSL_SERVER_M_SERIAL': cert.get_serial_number(),

 ##                'SSL_SERVER_V_START': Validity of server's certificate (start time),

 ##                'SSL_SERVER_V_END': Validity of server's certificate (end time),

                 })

             for prefix, dn in [("I", cert.get_issuer()),

                                ("S", cert.get_subject())]:

                 # X509Name objects don't seem to have a way to get the

                 # complete DN string. Use str() and slice it instead,

                 # because str(dn) == "<X509Name object '/C=US/ST=...'>"

                 dnstr = str(dn)[18:-2]

                 wsgikey = 'SSL_SERVER_%s_DN' % prefix

                 ssl_environ[wsgikey] = dnstr

                 # The DN should be of the form: /k1=v1/k2=v2, but we must allow

                 # for any value to contain slashes itself (in a URL).

                 while dnstr:

                     pos = dnstr.rfind("=")

                     dnstr, value = dnstr[:pos], dnstr[pos + 1:]

                     pos = dnstr.rfind("/")

                     dnstr, key = dnstr[:pos], dnstr[pos + 1:]

                     if key and value:

                         wsgikey = 'SSL_SERVER_%s_DN_%s' % (prefix, key)

                         ssl_environ[wsgikey] = value

         return ssl_environ

     def makefile(self, sock, mode='r', bufsize=-1):

         if SSL and isinstance(sock, SSL.ConnectionType):

             timeout = sock.gettimeout()

             f = SSL_fileobject(sock, mode, bufsize)

             f.ssl_timeout = timeout

             return f

         else:

             return wsgiserver.CP_fileobject(sock, mode, bufsize)