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# Copyright 2003 Ben Escoto
#
# This file is part of rdiff-backup.
#
# rdiff-backup is free software; you can redistribute it and/or modify
# 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.
#
# rdiff-backup 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 rdiff-backup; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
# USA
"""Store and retrieve extended attributes and access control lists
Not all file systems will have EAs and ACLs, but if they do, store
this information in separate files in the rdiff-backup-data directory,
called extended_attributes.<time>.snapshot and
access_control_lists.<time>.snapshot.
"""
from __future__ import generators
import base64, errno, re
import static, Globals, metadata, connection, rorpiter, log
class ExtendedAttributes:
"""Hold a file's extended attribute information"""
def __init__(self, index, attr_dict = None):
"""Initialize EA object with no attributes"""
self.index = index
if attr_dict is None: self.attr_dict = {}
else: self.attr_dict = attr_dict
def __eq__(self, ea):
"""Equal if all attributes and index are equal"""
assert isinstance(ea, ExtendedAttributes)
return ea.index == self.index and ea.attr_dict == self.attr_dict
def __ne__(self, ea): return not self.__eq__(ea)
def get_indexpath(self): return self.index and '/'.join(self.index) or '.'
def read_from_rp(self, rp):
"""Set the extended attributes from an rpath"""
try: attr_list = rp.conn.xattr.listxattr(rp.path)
except IOError, exc:
if exc[0] == errno.EOPNOTSUPP: return # if not sup, consider empty
raise
for attr in attr_list:
try: self.attr_dict[attr] = rp.conn.xattr.getxattr(rp.path, attr)
except IOError, exc:
# File probably modified while reading, just continue
if exc[0] == errno.ENODATA: continue
elif exc[0] == errno.ENOENT: break
else: raise
def clear_rp(self, rp):
"""Delete all the extended attributes in rpath"""
for name in rp.conn.xattr.listxattr(rp.path):
rp.conn.xattr.removexattr(rp.path, name)
def write_to_rp(self, rp):
"""Write extended attributes to rpath rp"""
self.clear_rp(rp)
for (name, value) in self.attr_dict.iteritems():
rp.conn.xattr.setxattr(rp.path, name, value)
def get(self, name):
"""Return attribute attached to given name"""
return self.attr_dict[name]
def set(self, name, value = ""):
"""Set given name to given value. Does not write to disk"""
self.attr_dict[name] = value
def delete(self, name):
"""Delete value associated with given name"""
del self.attr_dict[name]
def empty(self):
"""Return true if no extended attributes are set"""
return not self.attr_dict
def compare_rps(rp1, rp2):
"""Return true if rp1 and rp2 have same extended attributes"""
ea1 = ExtendedAttributes(rp1.index)
ea1.read_from_rp(rp1)
ea2 = ExtendedAttributes(rp2.index)
ea2.read_from_rp(rp2)
return ea1 == ea2
def EA2Record(ea):
"""Convert ExtendedAttributes object to text record"""
str_list = ['# file: %s' % ea.get_indexpath()]
for (name, val) in ea.attr_dict.iteritems():
if not val: str_list.append(name)
else:
encoded_val = base64.encodestring(val).replace('\n', '')
str_list.append('%s=0s%s' % (name, encoded_val))
return '\n'.join(str_list)+'\n'
def Record2EA(record):
"""Convert text record to ExtendedAttributes object"""
lines = record.split('\n')
first = lines.pop(0)
if not first[:8] == "# file: ":
raise metadata.ParsingError("Bad record beginning: " + first[:8])
filename = first[8:]
if filename == '.': index = ()
else: index = tuple(filename.split('/'))
ea = ExtendedAttributes(index)
for line in lines:
line = line.strip()
if not line: continue
assert line[0] != '#', line
eq_pos = line.find('=')
if eq_pos == -1: ea.set(line)
else:
name = line[:eq_pos]
assert line[eq_pos+1:eq_pos+3] == '0s', \
"Currently only base64 encoding supported"
encoded_val = line[eq_pos+3:]
ea.set(name, base64.decodestring(encoded_val))
return ea
def quote_path(path):
"""Quote a path for use EA/ACL records.
Right now no quoting!!! Change this to reflect the updated
quoting style of getfattr/setfattr when they are changed.
"""
return path
class EAExtractor(metadata.FlatExtractor):
"""Iterate ExtendedAttributes objects from the EA information file"""
record_boundary_regexp = re.compile("\\n# file:")
record_to_object = staticmethod(Record2EA)
def get_index_re(self, index):
"""Find start of EA record with given index"""
if not index: indexpath = '.'
else: indexpath = '/'.join(index)
# Right now there is no quoting, due to a bug in
# getfacl/setfacl. Replace later when bug fixed.
return re.compile('(^|\\n)(# file: %s\\n)' % indexpath)
class ExtendedAttributesFile(metadata.FlatFile):
"""Store/retrieve EAs from extended_attributes file"""
_prefix = "extended_attributes"
_extractor = EAExtractor
_object_to_record = staticmethod(EA2Record)
def get_combined_iter_at_time(cls, rbdir, rest_time,
restrict_index = None):
"""Return an iter of rorps with extended attributes added"""
def join_eas(basic_iter, ea_iter):
"""Join basic_iter with ea iter"""
collated = rorpiter.CollateIterators(basic_iter, ea_iter)
for rorp, ea in collated:
assert rorp, (rorp, (ea.index, ea.attr_dict), rest_time)
if not ea: ea = ExtendedAttributes(rorp.index)
rorp.set_ea(ea)
yield rorp
basic_iter = metadata.MetadataFile.get_objects_at_time(
Globals.rbdir, rest_time, restrict_index)
if not basic_iter: return None
ea_iter = cls.get_objects_at_time(rbdir, rest_time, restrict_index)
if not ea_iter:
log.Log("Warning: Extended attributes file not found", 2)
ea_iter = iter([])
return join_eas(basic_iter, ea_iter)
static.MakeClass(ExtendedAttributesFile)
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