/usr/lib/python2.7/dist-packages/nss_cache/caches/files.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.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 | # Copyright 2007 Google Inc.
#
# 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 a nss_files format local cache, with indexing.
libnss-cache is a NSS module that reads NSS data from files in /etc,
that look similar to the standard ones used by nss_files, but with
".cache" extension. It also uses an index file if one exists, in a
format created here.
"""
__author__ = ('jaq@google.com (Jamie Wilkinson)',
'vasilios@google.com (Vasilios Hoffman)')
import errno
import os.path
import re
import shutil
import stat
import sys
from nss_cache import config
from nss_cache import error
from nss_cache.caches import caches
from nss_cache.util import file_formats
if sys.version >= (2, 5):
def LongestLength(l): return len(max(l, key=len))
else: # Python < 2.4, 50% slower
def LongestLength(l): return max([len(x) for x in l])
def RegisterAllImplementations(register_callback):
"""Register our cache classes independently from the import scheme."""
register_callback('files', 'passwd', FilesPasswdMapHandler)
register_callback('files', 'sshkey', FilesSshkeyMapHandler)
register_callback('files', 'group', FilesGroupMapHandler)
register_callback('files', 'shadow', FilesShadowMapHandler)
register_callback('files', 'netgroup', FilesNetgroupMapHandler)
register_callback('files', 'automount', FilesAutomountMapHandler)
class FilesCache(caches.Cache):
"""An implementation of a Cache specific to nss_files module.
This implementation creates, updates, and verifies map caches used by
nss_files module.
Child classes can define the class attribute _INDEX_ATTRIBUTES, a
sequence-type of strings containing attributes of their associated
Map type that will be built into an index for use by libnss-cache.
"""
def __init__(self, conf, map_name, automount_mountpoint=None):
"""Create a handler for the given map type.
Args:
conf: a configuration object
map_name: a string representing the type of map we are
automount_mountpoint: A string containing the automount mountpoint, used
only by automount maps.
"""
super(FilesCache, self).__init__(conf, map_name,
automount_mountpoint=automount_mountpoint)
# Documented in nsscache.conf example.
self.cache_filename_suffix = conf.get('cache_filename_suffix', 'cache')
# Store a dict of indexes, each containing a dict of keys to line, position
# tuples.
self._indices = {}
if hasattr(self, '_INDEX_ATTRIBUTES'):
for index in self._INDEX_ATTRIBUTES:
self._indices[index] = {}
def GetMap(self, cache_filename=None):
"""Returns the map from the cache.
Args:
cache_filename: alternative file to read, optional.
Returns:
A child of Map containing the cache data.
Raises:
CacheNotFound: The cache file we expected to read from does not exist.
"""
data = self.data
if cache_filename is None:
cache_filename = self.GetCacheFilename()
self.log.debug('Opening %r for reading existing cache', cache_filename)
if not os.path.exists(cache_filename):
self.log.warning('Cache file does not exist, using an empty map instead')
else:
cache_file = open(cache_filename)
data = self.map_parser.GetMap(cache_file, data)
return data
def Verify(self, written_keys):
"""Verify that the cache is correct.
Perform some unit tests on the written data, such as reading it
back and verifying that it parses and has the entries we expect.
Args:
written_keys: a set of keys that should have been written to disk.
Returns:
a boolean indicating success.
Raises:
EmptyMap: The cache being verified is empty.
"""
self.log.debug('verification starting on %r', self.temp_cache_filename)
cache_data = self.GetMap(self.temp_cache_filename)
map_entry_count = len(cache_data)
self.log.debug('entry count: %d', map_entry_count)
if map_entry_count <= 0:
# We have read in an empty map, yet we expect that earlier we
# should have written more. Uncaught disk full or other error?
self.log.error('The files cache being verified "%r" is empty.',
self.temp_cache_filename)
raise error.EmptyMap(self.temp_cache_filename + ' is empty')
cache_keys = set()
# Use PopItem() so we free our memory if multiple maps are Verify()ed.
try:
while 1:
entry = cache_data.PopItem()
cache_keys.update(self._ExpectedKeysForEntry(entry))
except KeyError:
# expected when PopItem() is done, and breaks our loop for us.
pass
missing_from_cache = written_keys - cache_keys
if missing_from_cache:
self.log.warn('verify failed: %d missing from the on-disk cache',
len(missing_from_cache))
if len(missing_from_cache) < 1000:
self.log.debug('keys missing from the on-disk cache: %r',
missing_from_cache)
else:
self.log.debug('More than 1000 keys missing from cache. '
'Not printing.')
self._Rollback()
return False
missing_from_map = cache_keys - written_keys
if missing_from_map:
self.log.warn('verify failed: %d keys found, unexpected in the on-disk '
'cache', len(missing_from_map))
if len(missing_from_map) < 1000:
self.log.debug('keys missing from map: %r', missing_from_map)
else:
self.log.debug('More than 1000 keys missing from map. Not printing.')
self._Rollback()
return False
return True
def Write(self, map_data):
"""Write the map to the cache.
Warning -- this destroys map_data as it is written. This is done to save
memory and keep our peak footprint smaller. We consume memory again
on Verify() as we read a new copy of the entries back in.
Args:
map_data: A Map subclass containing the entire map to be written.
Returns:
a set of keys written or None on failure.
"""
self._Begin()
written_keys = set()
write_offset = 0
try:
while 1:
entry = map_data.PopItem()
for index in self._indices:
self._indices[index][str(getattr(entry, index))] = str(write_offset)
write_offset += self._WriteData(self.temp_cache_file, entry)
written_keys.update(self._ExpectedKeysForEntry(entry))
except KeyError:
# expected when PopItem() is done, and breaks our loop for us.
self.temp_cache_file.flush()
except:
self._Rollback()
raise
return written_keys
def GetCacheFilename(self):
"""Return the final destination pathname of the cache file."""
cache_filename_target = self.CACHE_FILENAME
if self.cache_filename_suffix:
cache_filename_target += '.' + self.cache_filename_suffix
return os.path.join(self.output_dir, cache_filename_target)
def WriteIndex(self):
"""Generate an index for libnss-cache from this map."""
for index_name in self._indices:
# magic string ".ix"
index_filename = '%s.ix%s' % (self.GetCacheFilename(), index_name)
self.log.debug('Writing index %s', index_filename)
index = self._indices[index_name]
key_length = LongestLength(index.keys())
pos_length = LongestLength(index.values())
max_length = key_length + pos_length
# Open for write/truncate
index_file = open(index_filename, 'w')
# setup permissions
try:
shutil.copymode(self.GetCompatFilename(), index_filename)
stat_info = os.stat(self.GetCompatFilename())
uid = stat_info.st_uid
gid = stat_info.st_gid
os.chown(index_filename, uid, gid)
except OSError, e:
if e.errno == errno.ENOENT:
os.chmod(index_filename,
stat.S_IRUSR|stat.S_IWUSR|stat.S_IRGRP|stat.S_IROTH)
for key in sorted(index):
pos = index[key]
index_line = ('%s\0%s\0%s\n' %
(key, pos,
'\0' * (max_length - len(key) - len(pos))))
index_file.write(index_line)
index_file.close()
class FilesSshkeyMapHandler(FilesCache):
"""Concrete class for updating a nss_files module sshkey cache."""
CACHE_FILENAME = 'sshkey'
_INDEX_ATTRIBUTES = ('name',)
def __init__(self, conf, map_name=None, automount_mountpoint=None):
if map_name is None: map_name = config.MAP_SSHKEY
super(FilesSshkeyMapHandler, self).__init__(
conf, map_name, automount_mountpoint=automount_mountpoint)
self.map_parser = file_formats.FilesSshkeyMapParser()
def _ExpectedKeysForEntry(self, entry):
"""Generate a list of expected cache keys for this type of map.
Args:
entry: A SshkeyMapEntry
Returns:
A list of strings
"""
return [entry.name]
def _WriteData(self, target, entry):
"""Write a SshekeyMapEntry to the target cache.
Args:
target: A file-like object.
entry: A SshkeyMapEntry.
Returns:
Number of bytes written to the target.
"""
sshkey_entry = '%s:%s' % (entry.name, entry.sshkey)
target.write(sshkey_entry + '\n')
return len(sshkey_entry) + 1
class FilesPasswdMapHandler(FilesCache):
"""Concrete class for updating a nss_files module passwd cache."""
CACHE_FILENAME = 'passwd'
_INDEX_ATTRIBUTES = ('name', 'uid')
def __init__(self, conf, map_name=None, automount_mountpoint=None):
if map_name is None: map_name = config.MAP_PASSWORD
super(FilesPasswdMapHandler, self).__init__(
conf, map_name, automount_mountpoint=automount_mountpoint)
self.map_parser = file_formats.FilesPasswdMapParser()
def _ExpectedKeysForEntry(self, entry):
"""Generate a list of expected cache keys for this type of map.
Args:
entry: A PasswdMapEntry
Returns:
A list of strings
"""
return [entry.name]
def _WriteData(self, target, entry):
"""Write a PasswdMapEntry to the target cache.
Args:
target: A file-like object.
entry: A PasswdMapEntry.
Returns:
Number of bytes written to the target.
"""
password_entry = '%s:%s:%d:%d:%s:%s:%s' % (entry.name, entry.passwd,
entry.uid, entry.gid,
entry.gecos, entry.dir,
entry.shell)
target.write(password_entry + '\n')
return len(password_entry) + 1
class FilesGroupMapHandler(FilesCache):
"""Concrete class for updating a nss_files module group cache."""
CACHE_FILENAME = 'group'
_INDEX_ATTRIBUTES = ('name', 'gid')
def __init__(self, conf, map_name=None, automount_mountpoint=None):
if map_name is None: map_name = config.MAP_GROUP
super(FilesGroupMapHandler, self).__init__(
conf, map_name, automount_mountpoint=automount_mountpoint)
self.map_parser = file_formats.FilesGroupMapParser()
def _ExpectedKeysForEntry(self, entry):
"""Generate a list of expected cache keys for this type of map.
Args:
entry: A GroupMapEntry
Returns:
A list of strings
"""
return [entry.name]
def _WriteData(self, target, entry):
"""Write a GroupMapEntry to the target cache."""
group_entry = '%s:%s:%d:%s' % (entry.name, entry.passwd, entry.gid,
','.join(entry.members))
target.write(group_entry + '\n')
return len(group_entry) + 1
class FilesShadowMapHandler(FilesCache):
"""Concrete class for updating a nss_files module shadow cache."""
CACHE_FILENAME = 'shadow'
_INDEX_ATTRIBUTES = ('name',)
def __init__(self, conf, map_name=None, automount_mountpoint=None):
if map_name is None: map_name = config.MAP_SHADOW
super(FilesShadowMapHandler, self).__init__(
conf, map_name, automount_mountpoint=automount_mountpoint)
self.map_parser = file_formats.FilesShadowMapParser()
def _ExpectedKeysForEntry(self, entry):
"""Generate a list of expected cache keys for this type of map.
Args:
entry: A ShadowMapEntry
Returns:
A list of strings
"""
return [entry.name]
def _WriteData(self, target, entry):
"""Write a ShadowMapEntry to the target cache."""
shadow_entry = '%s:%s:%s:%s:%s:%s:%s:%s:%s' % (entry.name,
entry.passwd,
entry.lstchg or '',
entry.min or '',
entry.max or '',
entry.warn or '',
entry.inact or '',
entry.expire or '',
entry.flag or '')
target.write(shadow_entry + '\n')
return len(shadow_entry) + 1
class FilesNetgroupMapHandler(FilesCache):
"""Concrete class for updating a nss_files module netgroup cache."""
CACHE_FILENAME = 'netgroup'
_TUPLE_RE = re.compile('^\((.*?),(.*?),(.*?)\)$') # Do this only once.
def __init__(self, conf, map_name=None, automount_mountpoint=None):
if map_name is None: map_name = config.MAP_NETGROUP
super(FilesNetgroupMapHandler, self).__init__(
conf, map_name, automount_mountpoint=automount_mountpoint)
self.map_parser = file_formats.FilesNetgroupMapParser()
def _ExpectedKeysForEntry(self, entry):
"""Generate a list of expected cache keys for this type of map.
Args:
entry: A NetgroupMapEntry
Returns:
A list of strings
"""
return [entry.name]
def _WriteData(self, target, entry):
"""Write a NetgroupMapEntry to the target cache."""
if entry.entries:
netgroup_entry = '%s %s' % (entry.name, entry.entries)
else:
netgroup_entry = entry.name
target.write(netgroup_entry + '\n')
return len(netgroup_entry) + 1
class FilesAutomountMapHandler(FilesCache):
"""Concrete class for updating a nss_files module automount cache."""
CACHE_FILENAME = None # we have multiple files, set as we update.
def __init__(self, conf, map_name=None, automount_mountpoint=None):
if map_name is None: map_name = config.MAP_AUTOMOUNT
super(FilesAutomountMapHandler, self).__init__(
conf, map_name, automount_mountpoint=automount_mountpoint)
self.map_parser = file_formats.FilesAutomountMapParser()
if automount_mountpoint is None:
# we are dealing with the master map
self.CACHE_FILENAME = 'auto.master'
else:
# turn /auto into auto.auto, and /usr/local into /auto.usr_local
automount_mountpoint = automount_mountpoint.lstrip('/')
self.CACHE_FILENAME = 'auto.%s' % automount_mountpoint.replace('/', '_')
def _ExpectedKeysForEntry(self, entry):
"""Generate a list of expected cache keys for this type of map.
Args:
entry: A AutomountMapEntry
Returns:
A list of strings
"""
return [entry.key]
def _WriteData(self, target, entry):
"""Write an AutomountMapEntry to the target cache."""
if entry.options is not None:
automount_entry = '%s %s %s' % (entry.key, entry.options, entry.location)
else:
automount_entry = '%s %s' % (entry.key, entry.location)
target.write(automount_entry + '\n')
return len(automount_entry) + 1
def GetMapLocation(self):
"""Get the location of this map for the automount master map."""
return self.GetCacheFilename()
|