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# Mount RPC client -- RFC 1094 (NFS), Appendix A
# This module demonstrates how to write your own RPC client in Python.
# When this example was written, there was no RPC compiler for
# Python. Without such a compiler, you must first create classes
# derived from Packer and Unpacker to handle the data types for the
# server you want to interface to. You then write the client class.
# If you want to support both the TCP and the UDP version of a
# protocol, use multiple inheritance as shown below.
import rpc
from rpc import Packer, Unpacker, TCPClient, UDPClient
# Program number and version for the mount protocol
MOUNTPROG = 100005
MOUNTVERS = 1
# Size of the 'fhandle' opaque structure
FHSIZE = 32
# Packer derived class for Mount protocol clients.
# The only thing we need to pack beyond basic types is an 'fhandle'
class MountPacker(Packer):
def pack_fhandle(self, fhandle):
self.pack_fopaque(FHSIZE, fhandle)
# Unpacker derived class for Mount protocol clients.
# The important types we need to unpack are fhandle, fhstatus,
# mountlist and exportlist; mountstruct, exportstruct and groups are
# used to unpack components of mountlist and exportlist and the
# corresponding functions are passed as function argument to the
# generic unpack_list function.
class MountUnpacker(Unpacker):
def unpack_fhandle(self):
return self.unpack_fopaque(FHSIZE)
def unpack_fhstatus(self):
status = self.unpack_uint()
if status == 0:
fh = self.unpack_fhandle()
else:
fh = None
return status, fh
def unpack_mountlist(self):
return self.unpack_list(self.unpack_mountstruct)
def unpack_mountstruct(self):
hostname = self.unpack_string()
directory = self.unpack_string()
return (hostname, directory)
def unpack_exportlist(self):
return self.unpack_list(self.unpack_exportstruct)
def unpack_exportstruct(self):
filesys = self.unpack_string()
groups = self.unpack_groups()
return (filesys, groups)
def unpack_groups(self):
return self.unpack_list(self.unpack_string)
# These are the procedures specific to the Mount client class.
# Think of this as a derived class of either TCPClient or UDPClient.
class PartialMountClient:
# This method is called by Client.__init__ to initialize
# self.packer and self.unpacker
def addpackers(self):
self.packer = MountPacker()
self.unpacker = MountUnpacker('')
# This method is called by Client.__init__ to bind the socket
# to a particular network interface and port. We use the
# default network interface, but if we're running as root,
# we want to bind to a reserved port
def bindsocket(self):
import os
try:
uid = os.getuid()
except AttributeError:
uid = 1
if uid == 0:
port = rpc.bindresvport(self.sock, '')
# 'port' is not used
else:
self.sock.bind(('', 0))
# This function is called to cough up a suitable
# authentication object for a call to procedure 'proc'.
def mkcred(self):
if self.cred is None:
self.cred = rpc.AUTH_UNIX, rpc.make_auth_unix_default()
return self.cred
# The methods Mnt, Dump etc. each implement one Remote
# Procedure Call. This is done by calling self.make_call()
# with as arguments:
#
# - the procedure number
# - the arguments (or None)
# - the "packer" function for the arguments (or None)
# - the "unpacker" function for the return value (or None)
#
# The packer and unpacker function, if not None, *must* be
# methods of self.packer and self.unpacker, respectively.
# A value of None means that there are no arguments or is no
# return value, respectively.
#
# The return value from make_call() is the return value from
# the remote procedure call, as unpacked by the "unpacker"
# function, or None if the unpacker function is None.
#
# (Even if you expect a result of None, you should still
# return the return value from make_call(), since this may be
# needed by a broadcasting version of the class.)
#
# If the call fails, make_call() raises an exception
# (this includes time-outs and invalid results).
#
# Note that (at least with the UDP protocol) there is no
# guarantee that a call is executed at most once. When you do
# get a reply, you know it has been executed at least once;
# when you don't get a reply, you know nothing.
def Mnt(self, directory):
return self.make_call(1, directory, \
self.packer.pack_string, \
self.unpacker.unpack_fhstatus)
def Dump(self):
return self.make_call(2, None, \
None, self.unpacker.unpack_mountlist)
def Umnt(self, directory):
return self.make_call(3, directory, \
self.packer.pack_string, None)
def Umntall(self):
return self.make_call(4, None, None, None)
def Export(self):
return self.make_call(5, None, \
None, self.unpacker.unpack_exportlist)
# We turn the partial Mount client into a full one for either protocol
# by use of multiple inheritance. (In general, when class C has base
# classes B1...Bn, if x is an instance of class C, methods of x are
# searched first in C, then in B1, then in B2, ..., finally in Bn.)
class TCPMountClient(PartialMountClient, TCPClient):
def __init__(self, host):
TCPClient.__init__(self, host, MOUNTPROG, MOUNTVERS)
class UDPMountClient(PartialMountClient, UDPClient):
def __init__(self, host):
UDPClient.__init__(self, host, MOUNTPROG, MOUNTVERS)
# A little test program for the Mount client. This takes a host as
# command line argument (default the local machine), prints its export
# list, and attempts to mount and unmount each exported files system.
# An optional first argument of -t or -u specifies the protocol to use
# (TCP or UDP), default is UDP.
def test():
import sys
if sys.argv[1:] and sys.argv[1] == '-t':
C = TCPMountClient
del sys.argv[1]
elif sys.argv[1:] and sys.argv[1] == '-u':
C = UDPMountClient
del sys.argv[1]
else:
C = UDPMountClient
if sys.argv[1:]: host = sys.argv[1]
else: host = ''
mcl = C(host)
list = mcl.Export()
for item in list:
print item
try:
mcl.Mnt(item[0])
except:
print 'Sorry'
continue
mcl.Umnt(item[0])
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