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# Copyright (C) 2005 Robey Pointer <robey@lag.net>
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# Copyright (C) 2005, 2006 Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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"""Foundation SSH support for SFTP and smart server."""
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from bzrlib.config import config_dir, ensure_config_dir_exists
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from bzrlib.errors import (ConnectionError,
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from bzrlib.osutils import pathjoin
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from bzrlib.trace import mutter, warning
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except ImportError, e:
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raise ParamikoNotPresent(e)
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from paramiko.sftp_client import SFTPClient
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_paramiko_version = getattr(paramiko, '__version_info__', (0, 0, 0))
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# Paramiko 1.5 tries to open a socket.AF_UNIX in order to connect
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# to ssh-agent. That attribute doesn't exist on win32 (it does in cygwin)
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# so we get an AttributeError exception. So we will not try to
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# connect to an agent if we are on win32 and using Paramiko older than 1.6
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_use_ssh_agent = (sys.platform != 'win32' or _paramiko_version >= (1, 6, 0))
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def register_ssh_vendor(name, vendor):
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"""Register SSH vendor."""
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_ssh_vendors[name] = vendor
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def _get_ssh_vendor():
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"""Find out what version of SSH is on the system."""
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if _ssh_vendor is not None:
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if 'BZR_SSH' in os.environ:
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vendor_name = os.environ['BZR_SSH']
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_ssh_vendor = _ssh_vendors[vendor_name]
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raise UnknownSSH(vendor_name)
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p = subprocess.Popen(['ssh', '-V'],
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stdin=subprocess.PIPE,
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stdout=subprocess.PIPE,
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stderr=subprocess.PIPE,
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**os_specific_subprocess_params())
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returncode = p.returncode
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stdout, stderr = p.communicate()
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if 'OpenSSH' in stderr:
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mutter('ssh implementation is OpenSSH')
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_ssh_vendor = OpenSSHSubprocessVendor()
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elif 'SSH Secure Shell' in stderr:
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mutter('ssh implementation is SSH Corp.')
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_ssh_vendor = SSHCorpSubprocessVendor()
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if _ssh_vendor is not None:
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# XXX: 20051123 jamesh
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# A check for putty's plink or lsh would go here.
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mutter('falling back to paramiko implementation')
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_ssh_vendor = ssh.ParamikoVendor()
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def _ignore_sigint():
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# TODO: This should possibly ignore SIGHUP as well, but bzr currently
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# doesn't handle it itself.
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# <https://launchpad.net/products/bzr/+bug/41433/+index>
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signal.signal(signal.SIGINT, signal.SIG_IGN)
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class LoopbackSFTP(object):
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"""Simple wrapper for a socket that pretends to be a paramiko Channel."""
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def __init__(self, sock):
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def send(self, data):
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return self.__socket.send(data)
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return self.__socket.recv(n)
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def recv_ready(self):
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self.__socket.close()
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class SSHVendor(object):
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"""Abstract base class for SSH vendor implementations."""
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def connect_sftp(self, username, password, host, port):
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"""Make an SSH connection, and return an SFTPClient.
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:param username: an ascii string
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:param password: an ascii string
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:param host: a host name as an ascii string
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:param port: a port number
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:raises: ConnectionError if it cannot connect.
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:rtype: paramiko.sftp_client.SFTPClient
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raise NotImplementedError(self.connect_sftp)
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def connect_ssh(self, username, password, host, port, command):
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"""Make an SSH connection, and return a pipe-like object.
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(This is currently unused, it's just here to indicate future directions
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raise NotImplementedError(self.connect_ssh)
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class LoopbackVendor(SSHVendor):
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"""SSH "vendor" that connects over a plain TCP socket, not SSH."""
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def connect_sftp(self, username, password, host, port):
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sock = socket.socket()
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sock.connect((host, port))
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except socket.error, e:
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raise ConnectionError('Unable to connect to SSH host %s:%s: %s'
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return SFTPClient(LoopbackSFTP(sock))
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register_ssh_vendor('loopback', LoopbackVendor())
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class ParamikoVendor(SSHVendor):
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"""Vendor that uses paramiko."""
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def connect_sftp(self, username, password, host, port):
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global SYSTEM_HOSTKEYS, BZR_HOSTKEYS
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t = paramiko.Transport((host, port or 22))
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t.set_log_channel('bzr.paramiko')
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except (paramiko.SSHException, socket.error), e:
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raise ConnectionError('Unable to reach SSH host %s:%s: %s'
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server_key = t.get_remote_server_key()
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server_key_hex = paramiko.util.hexify(server_key.get_fingerprint())
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keytype = server_key.get_name()
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if host in SYSTEM_HOSTKEYS and keytype in SYSTEM_HOSTKEYS[host]:
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our_server_key = SYSTEM_HOSTKEYS[host][keytype]
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our_server_key_hex = paramiko.util.hexify(our_server_key.get_fingerprint())
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elif host in BZR_HOSTKEYS and keytype in BZR_HOSTKEYS[host]:
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our_server_key = BZR_HOSTKEYS[host][keytype]
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our_server_key_hex = paramiko.util.hexify(our_server_key.get_fingerprint())
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warning('Adding %s host key for %s: %s' % (keytype, host, server_key_hex))
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if host not in BZR_HOSTKEYS:
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BZR_HOSTKEYS[host] = {}
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BZR_HOSTKEYS[host][keytype] = server_key
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our_server_key = server_key
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our_server_key_hex = paramiko.util.hexify(our_server_key.get_fingerprint())
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if server_key != our_server_key:
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filename1 = os.path.expanduser('~/.ssh/known_hosts')
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filename2 = pathjoin(config_dir(), 'ssh_host_keys')
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raise TransportError('Host keys for %s do not match! %s != %s' % \
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(host, our_server_key_hex, server_key_hex),
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['Try editing %s or %s' % (filename1, filename2)])
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_paramiko_auth(username, password, host, t)
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sftp = t.open_sftp_client()
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except paramiko.SSHException, e:
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raise ConnectionError('Unable to start sftp client %s:%d' %
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register_ssh_vendor('paramiko', ParamikoVendor())
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class SubprocessVendor(SSHVendor):
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"""Abstract base class for vendors that use pipes to a subprocess."""
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def connect_sftp(self, username, password, host, port):
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argv = self._get_vendor_specific_argv(username, host, port,
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proc = subprocess.Popen(argv,
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stdin=subprocess.PIPE,
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stdout=subprocess.PIPE,
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**os_specific_subprocess_params())
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sock = SSHSubprocess(proc)
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return SFTPClient(sock)
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except (EOFError, paramiko.SSHException), e:
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raise ConnectionError('Unable to connect to SSH host %s:%s: %s'
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except (OSError, IOError), e:
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# If the machine is fast enough, ssh can actually exit
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# before we try and send it the sftp request, which
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# raises a Broken Pipe
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if e.errno not in (errno.EPIPE,):
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raise ConnectionError('Unable to connect to SSH host %s:%s: %s'
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def _get_vendor_specific_argv(self, username, host, port, subsystem=None,
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"""Returns the argument list to run the subprocess with.
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Exactly one of 'subsystem' and 'command' must be specified.
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raise NotImplementedError(self._get_vendor_specific_argv)
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register_ssh_vendor('none', ParamikoVendor())
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class OpenSSHSubprocessVendor(SubprocessVendor):
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"""SSH vendor that uses the 'ssh' executable from OpenSSH."""
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def _get_vendor_specific_argv(self, username, host, port, subsystem=None,
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assert subsystem is not None or command is not None, (
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'Must specify a command or subsystem')
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if subsystem is not None:
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assert command is None, (
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'subsystem and command are mutually exclusive')
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'-oForwardX11=no', '-oForwardAgent=no',
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'-oClearAllForwardings=yes', '-oProtocol=2',
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'-oNoHostAuthenticationForLocalhost=yes']
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args.extend(['-p', str(port)])
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if username is not None:
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args.extend(['-l', username])
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if subsystem is not None:
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args.extend(['-s', host, subsystem])
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args.extend([host] + command)
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register_ssh_vendor('openssh', OpenSSHSubprocessVendor())
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class SSHCorpSubprocessVendor(SubprocessVendor):
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"""SSH vendor that uses the 'ssh' executable from SSH Corporation."""
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def _get_vendor_specific_argv(self, username, host, port, subsystem=None,
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assert subsystem is not None or command is not None, (
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'Must specify a command or subsystem')
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if subsystem is not None:
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assert command is None, (
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'subsystem and command are mutually exclusive')
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args.extend(['-p', str(port)])
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if username is not None:
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args.extend(['-l', username])
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if subsystem is not None:
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args.extend(['-s', subsystem, host])
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args.extend([host] + command)
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register_ssh_vendor('ssh', SSHCorpSubprocessVendor())
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def _paramiko_auth(username, password, host, paramiko_transport):
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# paramiko requires a username, but it might be none if nothing was supplied
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# use the local username, just in case.
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# We don't override username, because if we aren't using paramiko,
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# the username might be specified in ~/.ssh/config and we don't want to
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# force it to something else
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# Also, it would mess up the self.relpath() functionality
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username = username or getpass.getuser()
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agent = paramiko.Agent()
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for key in agent.get_keys():
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mutter('Trying SSH agent key %s' % paramiko.util.hexify(key.get_fingerprint()))
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paramiko_transport.auth_publickey(username, key)
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except paramiko.SSHException, e:
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# okay, try finding id_rsa or id_dss? (posix only)
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if _try_pkey_auth(paramiko_transport, paramiko.RSAKey, username, 'id_rsa'):
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if _try_pkey_auth(paramiko_transport, paramiko.DSSKey, username, 'id_dsa'):
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paramiko_transport.auth_password(username, password)
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except paramiko.SSHException, e:
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# give up and ask for a password
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password = bzrlib.ui.ui_factory.get_password(
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prompt='SSH %(user)s@%(host)s password',
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user=username, host=host)
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paramiko_transport.auth_password(username, password)
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except paramiko.SSHException, e:
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raise ConnectionError('Unable to authenticate to SSH host as %s@%s' %
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def _try_pkey_auth(paramiko_transport, pkey_class, username, filename):
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filename = os.path.expanduser('~/.ssh/' + filename)
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key = pkey_class.from_private_key_file(filename)
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paramiko_transport.auth_publickey(username, key)
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except paramiko.PasswordRequiredException:
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password = bzrlib.ui.ui_factory.get_password(
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prompt='SSH %(filename)s password',
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key = pkey_class.from_private_key_file(filename, password)
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paramiko_transport.auth_publickey(username, key)
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except paramiko.SSHException:
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mutter('SSH authentication via %s key failed.' % (os.path.basename(filename),))
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except paramiko.SSHException:
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mutter('SSH authentication via %s key failed.' % (os.path.basename(filename),))
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def load_host_keys():
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Load system host keys (probably doesn't work on windows) and any
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"discovered" keys from previous sessions.
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global SYSTEM_HOSTKEYS, BZR_HOSTKEYS
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SYSTEM_HOSTKEYS = paramiko.util.load_host_keys(os.path.expanduser('~/.ssh/known_hosts'))
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mutter('failed to load system host keys: ' + str(e))
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bzr_hostkey_path = pathjoin(config_dir(), 'ssh_host_keys')
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BZR_HOSTKEYS = paramiko.util.load_host_keys(bzr_hostkey_path)
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mutter('failed to load bzr host keys: ' + str(e))
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def save_host_keys():
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Save "discovered" host keys in $(config)/ssh_host_keys/.
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global SYSTEM_HOSTKEYS, BZR_HOSTKEYS
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bzr_hostkey_path = pathjoin(config_dir(), 'ssh_host_keys')
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ensure_config_dir_exists()
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f = open(bzr_hostkey_path, 'w')
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f.write('# SSH host keys collected by bzr\n')
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for hostname, keys in BZR_HOSTKEYS.iteritems():
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for keytype, key in keys.iteritems():
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f.write('%s %s %s\n' % (hostname, keytype, key.get_base64()))
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mutter('failed to save bzr host keys: ' + str(e))
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def os_specific_subprocess_params():
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"""Get O/S specific subprocess parameters."""
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if sys.platform == 'win32':
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# setting the process group and closing fds is not supported on
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# We close fds other than the pipes as the child process does not need
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# We also set the child process to ignore SIGINT. Normally the signal
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# would be sent to every process in the foreground process group, but
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# this causes it to be seen only by bzr and not by ssh. Python will
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# generate a KeyboardInterrupt in bzr, and we will then have a chance
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# to release locks or do other cleanup over ssh before the connection
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# <https://launchpad.net/products/bzr/+bug/5987>
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# Running it in a separate process group is not good because then it
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# can't get non-echoed input of a password or passphrase.
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# <https://launchpad.net/products/bzr/+bug/40508>
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return {'preexec_fn': _ignore_sigint,
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class SSHSubprocess(object):
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"""A socket-like object that talks to an ssh subprocess via pipes."""
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def __init__(self, proc):
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def send(self, data):
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return os.write(self.proc.stdin.fileno(), data)
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def recv_ready(self):
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# TODO: jam 20051215 this function is necessary to support the
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# pipelined() function. In reality, it probably should use
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# poll() or select() to actually return if there is data
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# available, otherwise we probably don't get any benefit
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def recv(self, count):
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return os.read(self.proc.stdout.fileno(), count)
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self.proc.stdin.close()
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self.proc.stdout.close()
added
removed
bzrlib/transport/ssh.py
