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# Copyright (C) 2006-2007 Robey Pointer <robeypointer@gmail.com>
# Copyright (C) 2012 Olle Lundberg <geek@nerd.sh>
#
# This file is part of paramiko.
#
# Paramiko is free software; you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 2.1 of the License, or (at your option)
# any later version.
#
# Paramiko is distrubuted in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
"""
L{SSHConfig}.
"""
import fnmatch
import os
import re
import socket
SSH_PORT = 22
proxy_re = re.compile(r"^(proxycommand)\s*=*\s*(.*)", re.I)
class LazyFqdn(object):
"""
Returns the host's fqdn on request as string.
"""
def __init__(self, config):
self.fqdn = None
self.config = config
def __str__(self):
if self.fqdn is None:
#
# If the SSH config contains AddressFamily, use that when
# determining the local host's FQDN. Using socket.getfqdn() from
# the standard library is the most general solution, but can
# result in noticeable delays on some platforms when IPv6 is
# misconfigured or not available, as it calls getaddrinfo with no
# address family specified, so both IPv4 and IPv6 are checked.
#
# Handle specific option
fqdn = None
address_family = self.config.get('addressfamily', 'any').lower()
if address_family != 'any':
family = socket.AF_INET if address_family == 'inet' \
else socket.AF_INET6
results = socket.getaddrinfo(host,
None,
family,
socket.SOCK_DGRAM,
socket.IPPROTO_IP,
socket.AI_CANONNAME)
for res in results:
af, socktype, proto, canonname, sa = res
if canonname and '.' in canonname:
fqdn = canonname
break
# Handle 'any' / unspecified
if fqdn is None:
fqdn = socket.getfqdn()
# Cache
self.fqdn = fqdn
return self.fqdn
class SSHConfig (object):
"""
Representation of config information as stored in the format used by
OpenSSH. Queries can be made via L{lookup}. The format is described in
OpenSSH's C{ssh_config} man page. This class is provided primarily as a
convenience to posix users (since the OpenSSH format is a de-facto
standard on posix) but should work fine on Windows too.
@since: 1.6
"""
def __init__(self):
"""
Create a new OpenSSH config object.
"""
self._config = []
def parse(self, file_obj):
"""
Read an OpenSSH config from the given file object.
@param file_obj: a file-like object to read the config file from
@type file_obj: file
"""
host = {"host": ['*'], "config": {}}
for line in file_obj:
line = line.rstrip('\n').lstrip()
if (line == '') or (line[0] == '#'):
continue
if '=' in line:
# Ensure ProxyCommand gets properly split
if line.lower().strip().startswith('proxycommand'):
match = proxy_re.match(line)
key, value = match.group(1).lower(), match.group(2)
else:
key, value = line.split('=', 1)
key = key.strip().lower()
else:
# find first whitespace, and split there
i = 0
while (i < len(line)) and not line[i].isspace():
i += 1
if i == len(line):
raise Exception('Unparsable line: %r' % line)
key = line[:i].lower()
value = line[i:].lstrip()
if key == 'host':
self._config.append(host)
value = value.split()
host = {key: value, 'config': {}}
#identityfile is a special case, since it is allowed to be
# specified multiple times and they should be tried in order
# of specification.
elif key == 'identityfile':
if key in host['config']:
host['config']['identityfile'].append(value)
else:
host['config']['identityfile'] = [value]
elif key not in host['config']:
host['config'].update({key: value})
self._config.append(host)
def lookup(self, hostname):
"""
Return a dict of config options for a given hostname.
The host-matching rules of OpenSSH's C{ssh_config} man page are used,
which means that all configuration options from matching host
specifications are merged, with more specific hostmasks taking
precedence. In other words, if C{"Port"} is set under C{"Host *"}
and also C{"Host *.example.com"}, and the lookup is for
C{"ssh.example.com"}, then the port entry for C{"Host *.example.com"}
will win out.
The keys in the returned dict are all normalized to lowercase (look for
C{"port"}, not C{"Port"}. The values are processed according to the
rules for substitution variable expansion in C{ssh_config}.
@param hostname: the hostname to lookup
@type hostname: str
"""
matches = [config for config in self._config if
self._allowed(hostname, config['host'])]
ret = {}
for match in matches:
for key, value in match['config'].iteritems():
if key not in ret:
# Create a copy of the original value,
# else it will reference the original list
# in self._config and update that value too
# when the extend() is being called.
ret[key] = value[:]
elif key == 'identityfile':
ret[key].extend(value)
ret = self._expand_variables(ret, hostname)
return ret
def _allowed(self, hostname, hosts):
match = False
for host in hosts:
if host.startswith('!') and fnmatch.fnmatch(hostname, host[1:]):
return False
elif fnmatch.fnmatch(hostname, host):
match = True
return match
def _expand_variables(self, config, hostname):
"""
Return a dict of config options with expanded substitutions
for a given hostname.
Please refer to man C{ssh_config} for the parameters that
are replaced.
@param config: the config for the hostname
@type hostname: dict
@param hostname: the hostname that the config belongs to
@type hostname: str
"""
if 'hostname' in config:
config['hostname'] = config['hostname'].replace('%h', hostname)
else:
config['hostname'] = hostname
if 'port' in config:
port = config['port']
else:
port = SSH_PORT
user = os.getenv('USER')
if 'user' in config:
remoteuser = config['user']
else:
remoteuser = user
host = socket.gethostname().split('.')[0]
fqdn = LazyFqdn(config)
homedir = os.path.expanduser('~')
replacements = {'controlpath':
[
('%h', config['hostname']),
('%l', fqdn),
('%L', host),
('%n', hostname),
('%p', port),
('%r', remoteuser),
('%u', user)
],
'identityfile':
[
('~', homedir),
('%d', homedir),
('%h', config['hostname']),
('%l', fqdn),
('%u', user),
('%r', remoteuser)
],
'proxycommand':
[
('%h', config['hostname']),
('%p', port),
('%r', remoteuser)
]
}
for k in config:
if k in replacements:
for find, replace in replacements[k]:
if isinstance(config[k], list):
for item in range(len(config[k])):
config[k][item] = config[k][item].\
replace(find, str(replace))
else:
config[k] = config[k].replace(find, str(replace))
return config
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