/usr/lib/python2.7/dist-packages/nss_cache/sources/httpsource.py is in nsscache 0.33-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
"""An implementation of an http data source for nsscache."""
__author__ = ('blaedd@google.com (David MacKinnon',)
import bz2
import calendar
import cStringIO
import logging
import os
import pycurl
import time
import urlparse
from nss_cache import error
from nss_cache.maps import automount
from nss_cache.maps import group
from nss_cache.maps import netgroup
from nss_cache.maps import passwd
from nss_cache.maps import shadow
from nss_cache.maps import sshkey
from nss_cache.sources import source
from nss_cache.util import file_formats
from nss_cache.util import curl
def RegisterImplementation(registration_callback):
registration_callback(HttpFilesSource)
class HttpFilesSource(source.Source):
"""Source for data fetched via HTTP."""
# HTTP defaults
PASSWD_URL = ''
SHADOW_URL = ''
GROUP_URL = ''
AUTOMOUNT_BASE_URL = ''
NETGROUP_URL = ''
SSHKEY_URL = ''
RETRY_DELAY = 5
RETRY_MAX = 3
TLS_CACERTFILE = '/etc/ssl/certs/ca-certificates.crt'
# for registration
name = 'http'
def __init__(self, conf, conn=None):
"""Initialise the HTTP Data Source.
Args:
conf: config.Config instance
conn: pycurl Curl object
"""
super(HttpFilesSource, self).__init__(conf)
self._SetDefaults(conf)
if not conn:
conn = pycurl.Curl()
conn.setopt(pycurl.NOPROGRESS, 1)
conn.setopt(pycurl.NOSIGNAL, 1)
# Don't hang on to connections from broken servers indefinitely.
conn.setopt(pycurl.TIMEOUT, 60)
conn.setopt(pycurl.USERAGENT, 'nsscache')
if self.conf['http_proxy']:
conn.setopt(pycurl.PROXY, self.conf['http_proxy'])
self.conn = conn
def _SetDefaults(self, configuration):
"""Set defaults if necessary."""
if not 'automount_base_url' in configuration:
configuration['automount_base_url'] = self.AUTOMOUNT_BASE_URL
if not 'passwd_url' in configuration:
configuration['passwd_url'] = self.PASSWD_URL
if not 'shadow_url' in configuration:
configuration['shadow_url'] = self.SHADOW_URL
if not 'group_url' in configuration:
configuration['group_url'] = self.GROUP_URL
if not 'netgroup_url' in configuration:
configuration['netgroup_url'] = self.GROUP_URL
if not 'sshkey_url' in configuration:
configuration['sshkey_url'] = self.SSHKEY_URL
if not 'retry_delay' in configuration:
configuration['retry_delay'] = self.RETRY_DELAY
if not 'retry_max' in configuration:
configuration['retry_max'] = self.RETRY_MAX
if not 'tls_cacertfile' in configuration:
configuration['tls_cacertfile'] = self.TLS_CACERTFILE
if not 'http_proxy' in configuration:
configuration['http_proxy'] = None
def GetPasswdMap(self, since=None):
"""Return the passwd map from this source.
Args:
since: Get data only changed since this timestamp (inclusive) or None
for all data.
Returns:
instance of passwd.PasswdMap
"""
return PasswdUpdateGetter().GetUpdates(self, self.conf['passwd_url'], since)
def GetShadowMap(self, since=None):
"""Return the shadow map from this source.
Args:
since: Get data only changed since this timestamp (inclusive) or None
for all data.
Returns:
instance of shadow.ShadowMap
"""
return ShadowUpdateGetter().GetUpdates(self, self.conf['shadow_url'],
since)
def GetGroupMap(self, since=None):
"""Return the group map from this source.
Args:
since: Get data only changed since this timestamp (inclusive) or None
for all data.
Returns:
instance of group.GroupMap
"""
return GroupUpdateGetter().GetUpdates(self, self.conf['group_url'], since)
def GetNetgroupMap(self, since=None):
"""Return the netgroup map from this source.
Args:
since: Get data only changed since this timestamp (inclusive) or None
for all data.
Returns:
instance of netgroup.NetgroupMap
"""
return NetgroupUpdateGetter().GetUpdates(self, self.conf['netgroup_url'],
since)
def GetAutomountMap(self, since=None, location=None):
"""Return an automount map from this source.
Note that autmount maps are stored in multiple locations, thus we expect
a caller to provide a location. We also follow the automount spec and
set our search scope to be 'one'.
Args:
location: Currently a string containing our search source, later we
may support hostname and additional parameters.
since: Get data only changed since this timestamp (inclusive) or None
for all data.
Returns:
instance of AutomountMap
Raises:
EmptyMap:
"""
if location is None:
self.log.error('A location is required to retrieve an automount map!')
raise error.EmptyMap
automount_url = urlparse.urljoin(self.conf['automount_base_url'],
location)
return AutomountUpdateGetter().GetUpdates(self, automount_url, since)
def GetAutomountMasterMap(self):
"""Return the autmount master map from this source.
Returns:
an instance of automount.AutomountMap
"""
master_map = self.GetAutomountMap(location='auto.master')
for map_entry in master_map:
map_entry.location = os.path.split(map_entry.location)[1]
self.log.debug('master map has: %s' % map_entry.location)
return master_map
def GetSshkeyMap(self, since=None):
"""Return the sshkey map from this source.
Args:
since: Get data only changed since this timestamp (inclusive) or None
for all data.
Returns:
instance of sshkey.SshkeyMap
"""
return SshkeyUpdateGetter().GetUpdates(self, self.conf['sshkey_url'], since)
class UpdateGetter(object):
"""Base class that gets updates over http."""
def __init__(self):
self.log = logging.getLogger(self.__class__.__name__)
def FromTimestampToHttp(self, ts):
"""Converts internal nss_cache timestamp to HTTP timestamp.
Args:
ts: number of seconds since epoch
Returns:
HTTP format timestamp string
"""
ts = time.gmtime(ts)
return time.strftime('%a, %d %b %Y %H:%M:%S GMT', ts)
def FromHttpToTimestamp(self, http_ts_string):
"""Converts HTTP timestamp string to internal nss_cache timestamp.
Args:
HTTP format timestamp string
Returns:
number of seconds since epoch
"""
t = time.strptime(http_ts_string, '%a, %d %b %Y %H:%M:%S GMT')
return int(calendar.timegm(t))
def GetUpdates(self, source, url, since):
"""Get updates from a source.
Args:
source: A data source
url: url to the data we want
since: a timestamp representing the last change (None to force-get)
Returns:
A tuple containing the map of updates and a maximum timestamp
Raises:
ValueError: an object in the source map is malformed
ConfigurationError:
"""
proto = url.split(':')[0]
# Newer libcurl allow you to disable protocols there. Unfortunately
# it's not in dapper or hardy.
if proto not in ('http', 'https'):
raise error.ConfigurationError('Unsupported protocol %s' % proto)
conn = source.conn
conn.setopt(pycurl.OPT_FILETIME, 1)
conn.setopt(pycurl.ENCODING, 'bzip2, gzip')
if since is not None:
conn.setopt(pycurl.TIMEVALUE, int(since))
conn.setopt(pycurl.TIMECONDITION, pycurl.TIMECONDITION_IFMODSINCE)
retry_count = 0
resp_code = 500
while retry_count < source.conf['retry_max']:
try:
source.log.debug('fetching %s', url)
(resp_code, headers, body) = curl.CurlFetch(url, conn, self.log)
self.log.debug('response code: %s', resp_code)
finally:
if resp_code < 400:
# Not modified-since
if resp_code == 304:
return []
if resp_code == 200:
break
retry_count += 1
self.log.warning('Failed connection: attempt #%s.', retry_count)
if retry_count == source.conf['retry_max']:
self.log.debug('max retries hit')
raise error.SourceUnavailable('Max retries exceeded.')
time.sleep(source.conf['retry_delay'])
headers = headers.split('\r\n')
last_modified = conn.getinfo(pycurl.INFO_FILETIME)
self.log.debug('last modified: %s', last_modified)
if last_modified == -1:
for header in headers:
if header.lower().startswith('last-modified'):
self.log.debug('%s', header)
http_ts_string = header[header.find(':')+1:].strip()
last_modified = self.FromHttpToTimestamp(http_ts_string)
break
else:
http_ts_string = ''
else:
http_ts_string = self.FromTimestampToHttp(last_modified)
self.log.debug('Last-modified is: %s', http_ts_string)
# curl (on Ubuntu hardy at least) will handle gzip, but not bzip2
try:
response = cStringIO.StringIO(bz2.decompress(body))
self.log.debug('bzip encoding found')
except IOError:
response = cStringIO.StringIO(body)
data_map = self.GetMap(cache_info=response)
if http_ts_string:
http_ts = self.FromHttpToTimestamp(http_ts_string)
self.log.debug('setting last modified to: %s', http_ts)
data_map.SetModifyTimestamp(http_ts)
return data_map
def GetParser(self):
"""Return the appropriate parser. Must be implemented by child class."""
raise NotImplementedError
def GetMap(self, cache_info):
"""Creates a Map from the cache_info data.
Args:
cache_info: file-like object containing the data to parse
Returns:
A child of Map containing the cache data.
"""
return self.GetParser().GetMap(cache_info, self.CreateMap())
class AutomountUpdateGetter(UpdateGetter):
"""Get automount updates."""
def GetParser(self):
"""Returns a MapParser to parse FilesAutomount cache."""
return file_formats.FilesAutomountMapParser()
def CreateMap(self):
"""Returns a new AutomountMap instance."""
return automount.AutomountMap()
class PasswdUpdateGetter(UpdateGetter):
"""Get passwd updates."""
def GetParser(self):
"""Returns a MapParser to parse FilesPasswd cache."""
return file_formats.FilesPasswdMapParser()
def CreateMap(self):
"""Returns a new PasswdMap instance to have PasswdMapEntries added to it."""
return passwd.PasswdMap()
class ShadowUpdateGetter(UpdateGetter):
"""Get shadow updates."""
def GetParser(self):
"""Returns a MapParser to parse FilesShadow cache."""
return file_formats.FilesShadowMapParser()
def CreateMap(self):
"""Returns a new ShadowMap instance to have ShadowMapEntries added to it."""
return shadow.ShadowMap()
class GroupUpdateGetter(UpdateGetter):
"""Get group updates."""
def GetParser(self):
"""Returns a MapParser to parse FilesGroup cache."""
return file_formats.FilesGroupMapParser()
def CreateMap(self):
"""Returns a new GroupMap instance to have GroupMapEntries added to it."""
return group.GroupMap()
class NetgroupUpdateGetter(UpdateGetter):
"""Get netgroup updates."""
def GetParser(self):
"""Returns a MapParser to parse FilesNetgroup cache."""
return file_formats.FilesNetgroupMapParser()
def CreateMap(self):
"""Returns a new NetgroupMap instance to have GroupMapEntries added to it."""
return netgroup.NetgroupMap()
class SshkeyUpdateGetter(UpdateGetter):
"""Get sshkey updates."""
def GetParser(self):
"""Returns a MapParser to parse FilesSshkey cache."""
return file_formats.FilesSshkeyMapParser()
def CreateMap(self):
"""Returns a new SshkeyMap instance to have SshkeyMapEntries added to it."""
return sshkey.SshkeyMap()
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