[project @ robey@master-shake.local-20060115063008-4f68552398868788]

fix a bunch of pychecker warnings, some of which were actual (but unlikely) bugs

19 files changed, 182 insertions, 134 deletions

diff --git a/README b/README
index 280a7ade..56081722 100644
--- a/README
+++ b/README
@@ -255,3 +255,6 @@ v1.0 JIGGLYPUFF
   key files, etc)
     local and remote port forwarding
 * SFTPClient.set_size
+* remove @since that predate 1.0
+* put examples in examples/ folder
+
diff --git a/paramiko/ber.py b/paramiko/ber.py
index 6a7823d8..e8d6d620 100644
--- a/paramiko/ber.py
+++ b/paramiko/ber.py
@@ -16,7 +16,7 @@
 # along with Paramiko; if not, write to the Free Software Foundation, Inc.,
 # 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 
-import struct
+
 import util
 
 
@@ -91,8 +91,9 @@ class BER(object):
         while True:
             x = b.decode_next()
             if x is None:
-                return out
+                break
             out.append(x)
+        return out
     decode_sequence = staticmethod(decode_sequence)
 
     def encode_tlv(self, ident, val):
diff --git a/paramiko/channel.py b/paramiko/channel.py
index 8a002339..ee2ec495 100644
--- a/paramiko/channel.py
+++ b/paramiko/channel.py
@@ -148,12 +148,7 @@ class Channel (object):
         m.add_string('')
         self.event.clear()
         self.transport._send_user_message(m)
-        while True:
-            self.event.wait(0.1)
-            if self.closed:
-                return False
-            if self.event.isSet():
-                return True
+        return self._wait_for_event()
 
     def invoke_shell(self):
         """
@@ -180,12 +175,7 @@ class Channel (object):
         m.add_boolean(1)
         self.event.clear()
         self.transport._send_user_message(m)
-        while True:
-            self.event.wait(0.1)
-            if self.closed:
-                return False
-            if self.event.isSet():
-                return True
+        return self._wait_for_event()
 
     def exec_command(self, command):
         """
@@ -212,12 +202,7 @@ class Channel (object):
         m.add_string(command)
         self.event.clear()
         self.transport._send_user_message(m)
-        while True:
-            self.event.wait(0.1)
-            if self.closed:
-                return False
-            if self.event.isSet():
-                return True
+        return self._wait_for_event()
 
     def invoke_subsystem(self, subsystem):
         """
@@ -243,12 +228,7 @@ class Channel (object):
         m.add_string(subsystem)
         self.event.clear()
         self.transport._send_user_message(m)
-        while True:
-            self.event.wait(0.1)
-            if self.closed:
-                return False
-            if self.event.isSet():
-                return True
+        return self._wait_for_event()
 
     def resize_pty(self, width=80, height=24):
         """
@@ -274,12 +254,7 @@ class Channel (object):
         m.add_int(0).add_int(0)
         self.event.clear()
         self.transport._send_user_message(m)
-        while True:
-            self.event.wait(0.1)
-            if self.closed:
-                return False
-            if self.event.isSet():
-                return True
+        self._wait_for_event()
 
     def recv_exit_status(self):
         """
@@ -296,8 +271,9 @@ class Channel (object):
         """
         while True:
             if self.closed or self.status_event.isSet():
-                return self.exit_status
+                break
             self.status_event.wait(0.1)
+        return self.exit_status
 
     def send_exit_status(self, status):
         """
@@ -1027,6 +1003,15 @@ class Channel (object):
     def _log(self, level, msg):
         self.logger.log(level, msg)
 
+    def _wait_for_event(self):
+        while True:
+            self.event.wait(0.1)
+            if self.closed:
+                return False
+            if self.event.isSet():
+                break
+        return True
+
     def _set_closed(self):
         # you are holding the lock.
         self.closed = True
@@ -1155,8 +1140,6 @@ class ChannelFile (BufferedFile):
     def _write(self, data):
         self.channel.sendall(data)
         return len(data)
-    
-    seek = BufferedFile.seek
 
 
 class ChannelStderrFile (ChannelFile):
diff --git a/paramiko/dsskey.py b/paramiko/dsskey.py
index 2b313723..dcb74115 100644
--- a/paramiko/dsskey.py
+++ b/paramiko/dsskey.py
@@ -36,6 +36,12 @@ class DSSKey (PKey):
     Representation of a DSS key which can be used to sign an verify SSH2
     data.
     """
+    
+    p = None
+    q = None
+    g = None
+    y = None
+    x = None
 
     def __init__(self, msg=None, data=None, filename=None, password=None, vals=None):
         if filename is not None:
@@ -81,7 +87,7 @@ class DSSKey (PKey):
         return self.size
         
     def can_sign(self):
-        return hasattr(self, 'x')
+        return self.x is not None
 
     def sign_ssh_data(self, rpool, data):
         digest = SHA.new(data).digest()
@@ -124,6 +130,8 @@ class DSSKey (PKey):
         return dss.verify(sigM, (sigR, sigS))
 
     def write_private_key_file(self, filename, password=None):
+        if self.x is None:
+            raise SSHException('Not enough key information')
         keylist = [ 0, self.p, self.q, self.g, self.y, self.x ]
         try:
             b = BER()
diff --git a/paramiko/file.py b/paramiko/file.py
index c29e7c45..43784745 100644
--- a/paramiko/file.py
+++ b/paramiko/file.py
@@ -45,6 +45,7 @@ class BufferedFile (object):
     SEEK_END = 2
 
     def __init__(self):
+        self.newlines = None
         self._flags = 0
         self._bufsize = self._DEFAULT_BUFSIZE
         self._wbuffer = StringIO()
@@ -55,6 +56,8 @@ class BufferedFile (object):
         # realpos - position according the OS
         # (these may be different because we buffer for line reading)
         self._pos = self._realpos = 0
+        # size only matters for seekable files
+        self._size = 0
 
     def __del__(self):
         self.close()
diff --git a/paramiko/kex_gex.py b/paramiko/kex_gex.py
index 994d76cb..3e322102 100644
--- a/paramiko/kex_gex.py
+++ b/paramiko/kex_gex.py
@@ -43,6 +43,12 @@ class KexGex (object):
 
     def __init__(self, transport):
         self.transport = transport
+        self.p = None
+        self.q = None
+        self.g = None
+        self.x = None
+        self.e = None
+        self.f = None
 
     def start_kex(self):
         if self.transport.server_mode:
diff --git a/paramiko/message.py b/paramiko/message.py
index 1d75a019..b110700d 100644
--- a/paramiko/message.py
+++ b/paramiko/message.py
@@ -285,7 +285,7 @@ class Message (object):
         elif type(i) is list:
             return self.add_list(i)
         else:
-            raise exception('Unknown type')
+            raise Exception('Unknown type')
 
     def add(self, *seq):
         """
diff --git a/paramiko/packet.py b/paramiko/packet.py
index 277d68e0..7e9afc78 100644
--- a/paramiko/packet.py
+++ b/paramiko/packet.py
@@ -219,7 +219,7 @@ class Packetizer (object):
             if n < 0:
                 raise EOFError()
             if n == len(out):
-                return
+                break
             out = out[n:]
         return
         
@@ -398,23 +398,24 @@ class Packetizer (object):
                 x = self.__socket.recv(1)
                 if len(x) == 0:
                     raise EOFError()
-                return x
+                break
             if self.__closed:
                 raise EOFError()
             now = time.time()
             if now - start >= timeout:
                 raise socket.timeout()
+        return x
 
     def _read_timeout(self, timeout):
         if PY22:
-            return self._py22_read_timeout(n)
+            return self._py22_read_timeout(timeout)
         start = time.time()
         while True:
             try:
                 x = self.__socket.recv(1)
                 if len(x) == 0:
                     raise EOFError()
-                return x
+                break
             except socket.timeout:
                 pass
             if self.__closed:
@@ -422,6 +423,7 @@ class Packetizer (object):
             now = time.time()
             if now - start >= timeout:
                 raise socket.timeout()
+        return x
 
     def _build_packet(self, payload):
         # pad up at least 4 bytes, to nearest block-size (usually 8)
diff --git a/paramiko/pipe.py b/paramiko/pipe.py
index cc28f43a..4048a14f 100644
--- a/paramiko/pipe.py
+++ b/paramiko/pipe.py
@@ -28,8 +28,10 @@ import socket
 
 def make_pipe ():
     if sys.platform[:3] != 'win':
-        return PosixPipe()
-    return WindowsPipe()
+        p = PosixPipe()
+    else:
+        p = WindowsPipe()
+    return p
 
 
 class PosixPipe (object):
diff --git a/paramiko/pkey.py b/paramiko/pkey.py
index 75db8e56..b6baf80b 100644
--- a/paramiko/pkey.py
+++ b/paramiko/pkey.py
@@ -173,7 +173,7 @@ class PKey (object):
         """
         return False
    
-    def from_private_key_file(cl, filename, password=None):
+    def from_private_key_file(cls, filename, password=None):
         """
         Create a key object by reading a private key file.  If the private
         key is encrypted and C{password} is not C{None}, the given password
@@ -197,7 +197,7 @@ class PKey (object):
 
         @since: fearow
         """
-        key = cl(filename=filename, password=password)
+        key = cls(filename=filename, password=password)
         return key
     from_private_key_file = classmethod(from_private_key_file)
 
@@ -216,7 +216,7 @@ class PKey (object):
 
         @since: fearow
         """
-        raise exception('Not implemented in PKey')
+        raise Exception('Not implemented in PKey')
 
     def _read_private_key_file(self, tag, filename, password=None):
         """
@@ -265,7 +265,7 @@ class PKey (object):
         # if we trudged to the end of the file, just try to cope.
         try:
             data = base64.decodestring(''.join(lines[start:end]))
-        except binascii.Error, e:
+        except base64.binascii.Error, e:
             raise SSHException('base64 decoding error: ' + str(e))
         if not headers.has_key('proc-type'):
             # unencryped: done
diff --git a/paramiko/primes.py b/paramiko/primes.py
index 36773944..fa0175d8 100644
--- a/paramiko/primes.py
+++ b/paramiko/primes.py
@@ -23,6 +23,7 @@ Utility functions for dealing with primes.
 from Crypto.Util import number
 
 from paramiko import util
+from paramiko.ssh_exception import SSHException
 
 
 def _generate_prime(bits, randpool):
@@ -39,7 +40,8 @@ def _generate_prime(bits, randpool):
         while not number.isPrime(n):
             n += 2
         if util.bit_length(n) == bits:
-            return n
+            break
+    return n
 
 def _roll_random(rpool, n):
     "returns a random # from 0 to N-1"
@@ -59,7 +61,8 @@ def _roll_random(rpool, n):
             x = chr(ord(x[0]) & hbyte_mask) + x[1:]
         num = util.inflate_long(x, 1)
         if num < n:
-            return num
+            break
+    return num
 
 
 class ModulusPack (object):
@@ -75,8 +78,8 @@ class ModulusPack (object):
         self.randpool = rpool
 
     def _parse_modulus(self, line):
-        timestamp, type, tests, tries, size, generator, modulus = line.split()
-        type = int(type)
+        timestamp, mod_type, tests, tries, size, generator, modulus = line.split()
+        mod_type = int(mod_type)
         tests = int(tests)
         tries = int(tries)
         size = int(size)
@@ -87,7 +90,7 @@ class ModulusPack (object):
         # type 2 (meets basic structural requirements)
         # test 4 (more than just a small-prime sieve)
         # tries < 100 if test & 4 (at least 100 tries of miller-rabin)
-        if (type < 2) or (tests < 4) or ((tests & 4) and (tests < 8) and (tries < 100)):
+        if (mod_type < 2) or (tests < 4) or ((tests & 4) and (tests < 8) and (tries < 100)):
             self.discarded.append((modulus, 'does not meet basic requirements'))
             return
         if generator == 0:
diff --git a/paramiko/rsakey.py b/paramiko/rsakey.py
index 780ea1b6..754e412a 100644
--- a/paramiko/rsakey.py
+++ b/paramiko/rsakey.py
@@ -38,6 +38,12 @@ class RSAKey (PKey):
     data.
     """
 
+    n = None
+    e = None
+    d = None
+    p = None
+    q = None
+    
     def __init__(self, msg=None, data=None, filename=None, password=None, vals=None):
         if filename is not None:
             self._from_private_key_file(filename, password)
@@ -75,7 +81,7 @@ class RSAKey (PKey):
         return self.size
 
     def can_sign(self):
-        return hasattr(self, 'd')
+        return self.d is not None
 
     def sign_ssh_data(self, rpool, data):
         digest = SHA.new(data).digest()
@@ -93,11 +99,13 @@ class RSAKey (PKey):
         # verify the signature by SHA'ing the data and encrypting it using the
         # public key.  some wackiness ensues where we "pkcs1imify" the 20-byte
         # hash into a string as long as the RSA key.
-        hash = util.inflate_long(self._pkcs1imify(SHA.new(data).digest()), True)
+        hash_obj = util.inflate_long(self._pkcs1imify(SHA.new(data).digest()), True)
         rsa = RSA.construct((long(self.n), long(self.e)))
-        return rsa.verify(hash, (sig,))
+        return rsa.verify(hash_obj, (sig,))
 
     def write_private_key_file(self, filename, password=None):
+        if (self.p is None) or (self.q is None):
+            raise SSHException('Not enough key info to write private key file')
         keylist = [ 0, self.n, self.e, self.d, self.p, self.q,
                     self.d % (self.p - 1), self.d % (self.q - 1),
                     util.mod_inverse(self.q, self.p) ]
diff --git a/paramiko/sftp_attr.py b/paramiko/sftp_attr.py
index eae7c993..0548dcd1 100644
--- a/paramiko/sftp_attr.py
+++ b/paramiko/sftp_attr.py
@@ -51,6 +51,12 @@ class SFTPAttributes (object):
         Create a new (empty) SFTPAttributes object.  All fields will be empty.
         """
         self._flags = 0
+        self.st_size = -1
+        self.st_uid = -1
+        self.st_gid = -1
+        self.st_mode = 0
+        self.st_atime = 0
+        self.st_mtime = 0
         self.attr = {}
 
     def from_stat(cls, obj, filename=None):
@@ -114,13 +120,13 @@ class SFTPAttributes (object):
 
     def _pack(self, msg):
         self._flags = 0
-        if hasattr(self, 'st_size'):
+        if self.st_size >= 0:
             self._flags |= self.FLAG_SIZE
-        if hasattr(self, 'st_uid') or hasattr(self, 'st_gid'):
+        if (self.st_uid >= 0) or (self.st_gid >= 0):
             self._flags |= self.FLAG_UIDGID
-        if hasattr(self, 'st_mode'):
+        if self.st_mode != 0:
             self._flags |= self.FLAG_PERMISSIONS
-        if hasattr(self, 'st_atime') or hasattr(self, 'st_mtime'):
+        if (self.st_atime > 0) or (self.st_mtime > 0):
             self._flags |= self.FLAG_AMTIME
         if len(self.attr) > 0:
             self._flags |= self.FLAG_EXTENDED
@@ -128,13 +134,13 @@ class SFTPAttributes (object):
         if self._flags & self.FLAG_SIZE:
             msg.add_int64(self.st_size)
         if self._flags & self.FLAG_UIDGID:
-            msg.add_int(getattr(self, 'st_uid', 0))
-            msg.add_int(getattr(self, 'st_gid', 0))
+            msg.add_int(self.st_uid)
+            msg.add_int(self.st_gid)
         if self._flags & self.FLAG_PERMISSIONS:
             msg.add_int(self.st_mode)
         if self._flags & self.FLAG_AMTIME:
-            msg.add_int(getattr(self, 'st_atime', 0))
-            msg.add_int(getattr(self, 'st_mtime', 0))
+            msg.add_int(self.st_atime)
+            msg.add_int(self.st_mtime)
         if self._flags & self.FLAG_EXTENDED:
             msg.add_int(len(self.attr))
             for key, val in self.attr.iteritems():
@@ -144,15 +150,14 @@ class SFTPAttributes (object):
 
     def _debug_str(self):
         out = '[ '
-        if hasattr(self, 'st_size'):
+        if self.st_size >= 0:
             out += 'size=%d ' % self.st_size
-        if hasattr(self, 'st_uid') or hasattr(self, 'st_gid'):
-            out += 'uid=%d gid=%d ' % (getattr(self, 'st_uid', 0), getattr(self, 'st_gid', 0))
-        if hasattr(self, 'st_mode'):
+        if (self.st_uid >= 0) or (self.st_gid >= 0):
+            out += 'uid=%d gid=%d ' % (self.st_uid, self.st_gid)
+        if self.st_mode != 0:
             out += 'mode=' + oct(self.st_mode) + ' '
-        if hasattr(self, 'st_atime') or hasattr(self, 'st_mtime'):
-            out += 'atime=%d mtime=%d ' % (getattr(self, 'st_atime', 0),
-                                           getattr(self, 'st_mtime', 0))
+        if (self.st_atime > 0) or (self.st_mtime > 0):
+            out += 'atime=%d mtime=%d ' % (self.st_atime, self.st_mtime)
         for k, v in self.attr.iteritems():
             out += '"%s"=%r ' % (str(k), v)
         out += ']'
@@ -171,7 +176,7 @@ class SFTPAttributes (object):
 
     def __str__(self):
         "create a unix-style long description of the file (like ls -l)"
-        if hasattr(self, 'st_mode'):
+        if self.st_mode != 0:
             kind = stat.S_IFMT(self.st_mode)
             if kind == stat.S_IFIFO:
                 ks = 'p'
@@ -194,15 +199,12 @@ class SFTPAttributes (object):
             ks += self._rwx(self.st_mode & 7, self.st_mode & stat.S_ISVTX, True)
         else:
             ks = '?---------'
-        uid = getattr(self, 'st_uid', -1)
-        gid = getattr(self, 'st_gid', -1)
-        size = getattr(self, 'st_size', -1)
-        mtime = getattr(self, 'st_mtime', 0)
         # compute display date
-        if abs(time.time() - mtime) > 15552000:
+        if abs(time.time() - self.st_mtime) > 15552000:
             # (15552000 = 6 months)
-            datestr = time.strftime('%d %b %Y', time.localtime(mtime))
+            datestr = time.strftime('%d %b %Y', time.localtime(self.st_mtime))
         else:
-            datestr = time.strftime('%d %b %H:%M', time.localtime(mtime))
+            datestr = time.strftime('%d %b %H:%M', time.localtime(self.st_mtime))
         filename = getattr(self, 'filename', '?')
-        return '%s   1 %-8d %-8d %8d %-12s %s' % (ks, uid, gid, size, datestr, filename)
+        return '%s   1 %-8d %-8d %8d %-12s %s' % (ks, self.st_uid, self.st_gid,
+            self.st_size, datestr, filename)
diff --git a/paramiko/sftp_client.py b/paramiko/sftp_client.py
index 2fe89e91..ba37455f 100644
--- a/paramiko/sftp_client.py
+++ b/paramiko/sftp_client.py
@@ -23,6 +23,7 @@ Client-mode SFTP support.
 import errno
 import os
 import threading
+import time
 import weakref
 from paramiko.sftp import *
 from paramiko.sftp_attr import SFTPAttributes
@@ -74,7 +75,7 @@ class SFTPClient (BaseSFTP):
     def __del__(self):
         self.close()
 
-    def from_transport(selfclass, t):
+    def from_transport(cls, t):
         """
         Create an SFTP client channel from an open L{Transport}.
 
@@ -89,7 +90,7 @@ class SFTPClient (BaseSFTP):
             return None
         if not chan.invoke_subsystem('sftp'):
             raise SFTPError('Failed to invoke sftp subsystem')
-        return selfclass(chan)
+        return cls(chan)
     from_transport = classmethod(from_transport)
 
     def close(self):
@@ -560,7 +561,7 @@ class SFTPClient (BaseSFTP):
                 self._log(DEBUG, 'Unexpected response #%d' % (num,))
                 if waitfor is None:
                     # just doing a single check
-                    return
+                    break
                 continue
             fileobj = self._expecting[num]
             del self._expecting[num]
@@ -573,7 +574,8 @@ class SFTPClient (BaseSFTP):
                 fileobj._async_response(t, msg)
             if waitfor is None:
                 # just doing a single check
-                return
+                break
+        return (None, None)
 
     def _finish_responses(self, fileobj):
         while fileobj in self._expecting.values():
diff --git a/paramiko/sftp_file.py b/paramiko/sftp_file.py
index f224f025..bdc60c7a 100644
--- a/paramiko/sftp_file.py
+++ b/paramiko/sftp_file.py
@@ -43,12 +43,18 @@ class SFTPFile (BufferedFile):
         BufferedFile._set_mode(self, mode, bufsize)
         self.pipelined = False
         self._prefetching = False
+        self._prefetch_so_far = 0
+        self._prefetch_size = 0
+        self._prefetch_data = {}
         self._saved_exception = None
 
     def __del__(self):
-        self.close(_async=True)
+        self._close(async=True)
+    
+    def close(self):
+        self._close(async=False)
         
-    def close(self, _async=False):
+    def _close(self, async=False):
         # We allow double-close without signaling an error, because real
         # Python file objects do.  However, we must protect against actually
         # sending multiple CMD_CLOSE packets, because after we close our
@@ -62,7 +68,7 @@ class SFTPFile (BufferedFile):
             self.sftp._finish_responses(self)
         BufferedFile.close(self)
         try:
-            if _async:
+            if async:
                 # GC'd file handle could be called from an arbitrary thread -- don't wait for a response
                 self.sftp._async_request(type(None), CMD_CLOSE, self.handle)
             else:
diff --git a/paramiko/sftp_handle.py b/paramiko/sftp_handle.py
index e1d93e9f..11a72c2b 100644
--- a/paramiko/sftp_handle.py
+++ b/paramiko/sftp_handle.py
@@ -81,15 +81,16 @@ class SFTPHandle (object):
         @return: data read from the file, or an SFTP error code.
         @rtype: str
         """
-        if not hasattr(self, 'readfile') or (self.readfile is None):
+        readfile = getattr(self, 'readfile', None)
+        if readfile is None:
             return SFTP_OP_UNSUPPORTED
         try:
             if self.__tell is None:
-                self.__tell = self.readfile.tell()
+                self.__tell = readfile.tell()
             if offset != self.__tell:
-                self.readfile.seek(offset)
+                readfile.seek(offset)
                 self.__tell = offset
-            data = self.readfile.read(length)
+            data = readfile.read(length)
         except IOError, e:
             self.__tell = None
             return SFTPServer.convert_errno(e.errno)
@@ -116,16 +117,17 @@ class SFTPHandle (object):
         @type data: str
         @return: an SFTP error code like L{SFTP_OK}.
         """
-        if not hasattr(self, 'writefile') or (self.writefile is None):
+        writefile = getattr(self, 'writefile', None)
+        if writefile is None:
             return SFTP_OP_UNSUPPORTED
         try:
             if self.__tell is None:
-                self.__tell = self.writefile.tell()
+                self.__tell = writefile.tell()
             if offset != self.__tell:
-                self.writefile.seek(offset)
+                writefile.seek(offset)
                 self.__tell = offset
-            self.writefile.write(data)
-            self.writefile.flush()
+            writefile.write(data)
+            writefile.flush()
         except IOError, e:
             self.__tell = None
             return SFTPServer.convert_errno(e.errno)
diff --git a/paramiko/sftp_server.py b/paramiko/sftp_server.py
index 7b634838..253cffb3 100644
--- a/paramiko/sftp_server.py
+++ b/paramiko/sftp_server.py
@@ -246,29 +246,29 @@ class SFTPServer (BaseSFTP, SubsystemHandler):
             self._send_status(request_number, SFTP_FAILURE, 'Block size too small')
             return
 
-        sum = ''
+        sum_out = ''
         offset = start
         while offset < start + length:
             blocklen = min(block_size, start + length - offset)
             # don't try to read more than about 64KB at a time
             chunklen = min(blocklen, 65536)
             count = 0
-            hash = alg.new()
+            hash_obj = alg.new()
             while count < blocklen:
                 data = f.read(offset, chunklen)
                 if not type(data) is str:
                     self._send_status(request_number, data, 'Unable to hash file')
                     return
-                hash.update(data)
+                hash_obj.update(data)
                 count += len(data)
                 offset += count
-            sum += hash.digest()
+            sum_out += hash_obj.digest()
 
         msg = Message()
         msg.add_int(request_number)
         msg.add_string('check-file')
         msg.add_string(algname)
-        msg.add_bytes(sum)
+        msg.add_bytes(sum_out)
         self._send_packet(CMD_EXTENDED_REPLY, str(msg))
     
     def _convert_pflags(self, pflags):
@@ -412,7 +412,7 @@ class SFTPServer (BaseSFTP, SubsystemHandler):
             if tag == 'check-file':
                 self._check_file(request_number, msg)
             else:
-                send._send_status(request_number, SFTP_OP_UNSUPPORTED)
+                self._send_status(request_number, SFTP_OP_UNSUPPORTED)
         else:
             self._send_status(request_number, SFTP_OP_UNSUPPORTED)
 
diff --git a/paramiko/transport.py b/paramiko/transport.py
index 8714a960..abc1ea96 100644
--- a/paramiko/transport.py
+++ b/paramiko/transport.py
@@ -30,19 +30,20 @@ import time
 import weakref
 
 from paramiko import util
+from paramiko.auth_handler import AuthHandler
+from paramiko.channel import Channel
 from paramiko.common import *
 from paramiko.compress import ZlibCompressor, ZlibDecompressor
-from paramiko.ssh_exception import SSHException, BadAuthenticationType
-from paramiko.message import Message
-from paramiko.channel import Channel
-from paramiko.sftp_client import SFTPClient
-from paramiko.packet import Packetizer, NeedRekeyException
-from paramiko.rsakey import RSAKey
 from paramiko.dsskey import DSSKey
-from paramiko.kex_group1 import KexGroup1
 from paramiko.kex_gex import KexGex
+from paramiko.kex_group1 import KexGroup1
+from paramiko.message import Message
+from paramiko.packet import Packetizer, NeedRekeyException
 from paramiko.primes import ModulusPack
-from paramiko.auth_handler import AuthHandler
+from paramiko.rsakey import RSAKey
+from paramiko.server import ServerInterface
+from paramiko.sftp_client import SFTPClient
+from paramiko.ssh_exception import SSHException, BadAuthenticationType
 
 # these come from PyCrypt
 #     http://www.amk.ca/python/writing/pycrypt/
@@ -110,7 +111,8 @@ class SecurityOptions (object):
         if type(x) is not tuple:
             raise TypeError('expected tuple or list')
         possible = getattr(self._transport, orig).keys()
-        if len(filter(lambda n: n not in possible, x)) > 0:
+        forbidden = filter(lambda n: n not in possible, x)
+        if len(forbidden) > 0:
             raise ValueError('unknown cipher')
         setattr(self._transport, name, x)
 
@@ -245,25 +247,39 @@ class Transport (threading.Thread):
             self.sock.settimeout(0.1)
         except AttributeError:
             pass
+
         # negotiated crypto parameters
         self.packetizer = Packetizer(sock)
         self.local_version = 'SSH-' + self._PROTO_ID + '-' + self._CLIENT_ID
         self.remote_version = ''
         self.local_cipher = self.remote_cipher = ''
         self.local_kex_init = self.remote_kex_init = None
+        self.local_mac = self.remote_mac = None
+        self.local_compression = self.remote_compression = None
         self.session_id = None
-        # /negotiated crypto parameters
-        self.expected_packet = 0
+        self.host_key_type = None
+        self.host_key = None
+        
+        # state used during negotiation
+        self.kex_engine = None
+        self.H = None
+        self.K = None
+
         self.active = False
         self.initial_kex_done = False
         self.in_kex = False
+        self.authenticated = False
+        self.expected_packet = 0
         self.lock = threading.Lock()    # synchronization (always higher level than write_lock)
+
+        # tracking open channels
         self.channels = weakref.WeakValueDictionary()   # (id -> Channel)
         self.channel_events = { }       # (id -> Event)
         self.channels_seen = { }        # (id -> True)
         self.channel_counter = 1
         self.window_size = 65536
         self.max_packet_size = 34816
+
         self.saved_exception = None
         self.clear_to_send = threading.Event()
         self.clear_to_send_lock = threading.Lock()
@@ -271,9 +287,9 @@ class Transport (threading.Thread):
         self.logger = util.get_logger(self.log_name)
         self.packetizer.set_log(self.logger)
         self.auth_handler = None
-        self.authenticated = False
-        # user-defined event callbacks:
-        self.completion_event = None
+        self.global_response = None     # response Message from an arbitrary global request
+        self.completion_event = None    # user-defined event callbacks
+        
         # server mode:
         self.server_mode = False
         self.server_object = None
@@ -993,7 +1009,7 @@ class Transport (threading.Thread):
             return self.auth_handler.wait_for_response(my_event)
         except BadAuthenticationType, x:
             # if password auth isn't allowed, but keyboard-interactive *is*, try to fudge it
-            if not fallback or not 'keyboard-interactive' in x.allowed_types:
+            if not fallback or ('keyboard-interactive' not in x.allowed_types):
                 raise
             try:
                 def handler(title, instructions, fields):
@@ -1010,6 +1026,7 @@ class Transport (threading.Thread):
             except SSHException, ignored:
                 # attempt failed; just raise the original exception
                 raise x
+                return None
 
     def auth_publickey(self, username, key, event=None):
         """
@@ -1262,9 +1279,9 @@ class Transport (threading.Thread):
             m.add_mpint(self.K)
             m.add_bytes(self.H)
             m.add_bytes(sofar)
-            hash = SHA.new(str(m)).digest()
-            out += hash
-            sofar += hash
+            digest = SHA.new(str(m)).digest()
+            out += digest
+            sofar += digest
         return out[:nbytes]
 
     def _get_cipher(self, name, key, iv):
@@ -1394,24 +1411,24 @@ class Transport (threading.Thread):
             else:
                 timeout = 2
             try:
-                buffer = self.packetizer.readline(timeout)
+                buf = self.packetizer.readline(timeout)
             except Exception, x:
                 raise SSHException('Error reading SSH protocol banner' + str(x))
-            if buffer[:4] == 'SSH-':
+            if buf[:4] == 'SSH-':
                 break
-            self._log(DEBUG, 'Banner: ' + buffer)
-        if buffer[:4] != 'SSH-':
-            raise SSHException('Indecipherable protocol version "' + buffer + '"')
+            self._log(DEBUG, 'Banner: ' + buf)
+        if buf[:4] != 'SSH-':
+            raise SSHException('Indecipherable protocol version "' + buf + '"')
         # save this server version string for later
-        self.remote_version = buffer
+        self.remote_version = buf
         # pull off any attached comment
         comment = ''
-        i = string.find(buffer, ' ')
+        i = string.find(buf, ' ')
         if i >= 0:
-            comment = buffer[i+1:]
-            buffer = buffer[:i]
+            comment = buf[i+1:]
+            buf = buf[:i]
         # parse out version string and make sure it matches
-        segs = buffer.split('-', 2)
+        segs = buf.split('-', 2)
         if len(segs) < 3:
             raise SSHException('Invalid SSH banner')
         version = segs[1]
diff --git a/paramiko/util.py b/paramiko/util.py
index abab825d..77eee3f6 100644
--- a/paramiko/util.py
+++ b/paramiko/util.py
@@ -168,12 +168,12 @@ def generate_key_bytes(hashclass, salt, key, nbytes):
     if len(salt) > 8:
         salt = salt[:8]
     while nbytes > 0:
-        hash = hashclass.new()
+        hash_obj = hashclass.new()
         if len(digest) > 0:
-            hash.update(digest)
-        hash.update(key)
-        hash.update(salt)
-        digest = hash.digest()
+            hash_obj.update(digest)
+        hash_obj.update(key)
+        hash_obj.update(salt)
+        digest = hash_obj.digest()
         size = min(nbytes, len(digest))
         keydata += digest[:size]
         nbytes -= size