95 lines
3.2 KiB
Python
95 lines
3.2 KiB
Python
# Copyright (C) 2012 Yipit, Inc <coders@yipit.com>
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#
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# This file is part of paramiko.
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#
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# Paramiko is free software; you can redistribute it and/or modify it under the
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# terms of the GNU Lesser General Public License as published by the Free
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# Software Foundation; either version 2.1 of the License, or (at your option)
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# any later version.
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#
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# Paramiko is distrubuted in the hope that it will be useful, but WITHOUT ANY
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# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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# A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
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# details.
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#
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# You should have received a copy of the GNU Lesser General Public License
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# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
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# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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"""
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L{ProxyCommand}.
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"""
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import os
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import sys
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from shlex import split as shlsplit
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import signal
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from subprocess import Popen, PIPE
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from paramiko.ssh_exception import ProxyCommandFailure
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class ProxyCommand(object):
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"""
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Wraps a subprocess running ProxyCommand-driven programs.
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This class implements a the socket-like interface needed by the
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L{Transport} and L{Packetizer} classes. Using this class instead of a
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regular socket makes it possible to talk with a Popen'd command that will
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proxy traffic between the client and a server hosted in another machine.
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"""
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def __init__(self, command_line):
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"""
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Create a new CommandProxy instance. The instance created by this
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class can be passed as an argument to the L{Transport} class.
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@param command_line: the command that should be executed and
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used as the proxy.
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@type command_line: str
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"""
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self.cmd = shlsplit(command_line)
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self.process = Popen(self.cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE)
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def send(self, content):
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"""
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Write the content received from the SSH client to the standard
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input of the forked command.
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@param content: string to be sent to the forked command
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@type content: str
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"""
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try:
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self.process.stdin.write(content)
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except IOError:
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e = sys.exc_info()[1]
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# There was a problem with the child process. It probably
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# died and we can't proceed. The best option here is to
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# raise an exception informing the user that the informed
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# ProxyCommand is not working.
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raise ProxyCommandFailure(' '.join(self.cmd), e.strerror)
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return len(content)
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def recv(self, size):
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"""
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Read from the standard output of the forked program.
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@param size: how many chars should be read
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@type size: int
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@return: the length of the read content
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@rtype: int
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"""
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try:
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return os.read(self.process.stdout.fileno(), size)
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except IOError:
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e = sys.exc_info()[1]
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raise ProxyCommandFailure(' '.join(self.cmd), e.strerror)
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def close(self):
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os.kill(self.process.pid, signal.SIGTERM)
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def settimeout(self, timeout):
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# Timeouts are meaningless for this implementation, but are part of the
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# spec, so must be present.
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pass
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