1 files changed, 395 insertions, 0 deletions
diff --git a/rdiff-backup/rdiff_backup/eas_acls.py b/rdiff-backup/rdiff_backup/eas_acls.py
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+++ b/rdiff-backup/rdiff_backup/eas_acls.py
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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
+try: import posix1e
+except ImportError: pass
+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:
+			if not attr.startswith('user.'):
+				# Only preserve user extended attributes
+				continue
+			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 ea_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 join(cls, rorp_iter, rbdir, time, restrict_index):
+		"""Add extended attribute information to existing rorp_iter"""
+		def helper(rorp_iter, ea_iter):
+			"""Add EA information in ea_iter to rorp_iter"""
+			collated = rorpiter.CollateIterators(rorp_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
+			
+		ea_iter = cls.get_objects_at_time(rbdir, time, restrict_index)
+		if ea_iter: return helper(rorp_iter, ea_iter)
+		else:
+			log.Log("Warning: Extended attributes file not found",2)
+			return rorp_iter
+
+static.MakeClass(ExtendedAttributesFile)
+
+
+class AccessControlList:
+	"""Hold a file's access control list information
+
+	Since ACL objects cannot be picked, store everything as text, in
+	self.acl_text and self.def_acl_text.
+
+	"""
+	def __init__(self, index, acl_text = None, def_acl_text = None):
+		"""Initialize object with index and possibly acl_text"""
+		self.index = index
+		if acl_text: # Check validity of ACL, reorder if necessary
+			ACL = posix1e.ACL(text=acl_text)
+			assert ACL.valid(), "Bad ACL: "+acl_text
+			self.acl_text = str(ACL)
+		else: self.acl_text = None
+
+		if def_acl_text:
+			def_ACL = posix1e.ACL(text=def_acl_text)
+			assert def_ACL.valid(), "Bad default ACL: "+def_acl_text
+			self.def_acl_text = str(def_ACL)
+		else: self.def_acl_text = None
+
+	def __str__(self):
+		"""Return human-readable string"""
+		return ("acl_text: %s\ndef_acl_text: %s" %
+				(self.acl_text, self.def_acl_text))
+
+	def __eq__(self, acl):
+		"""Compare self and other access control list
+
+		Basic acl permissions are considered equal to an empty acl
+		object.
+
+		"""
+		assert isinstance(acl, self.__class__)
+		if self.index != acl.index: return 0
+		if self.is_basic(): return acl.is_basic()
+		if acl.is_basic(): return self.is_basic()
+		if self.acl_text != acl.acl_text: return 0
+		if not self.def_acl_text and not acl.def_acl_text: return 1
+		return self.def_acl_text == acl.def_acl_text
+	def __ne__(self, acl): return not self.__eq__(acl)
+	
+	def eq_verbose(self, acl):
+		"""Returns same as __eq__ but print explanation if not equal"""
+		if self.index != acl.index:
+			print "index %s not equal to index %s" % (self.index, acl.index)
+			return 0
+		if self.acl_text != acl.acl_text:
+			print "ACL texts not equal:"
+			print self.acl_text
+			print acl.acl_text
+			return 0
+		if (self.def_acl_text != acl.def_acl_text and
+			(self.def_acl_text or acl.def_acl_text)):
+			print "Unequal default acl texts:"
+			print self.def_acl_text
+			print acl.def_acl_text
+			return 0
+		return 1
+
+	def get_indexpath(self): return self.index and '/'.join(self.index) or '.'
+
+	def is_basic(self):
+		"""True if acl can be reduced to standard unix permissions
+
+		Assume that if they are only three entries, they correspond to
+		user, group, and other, and thus don't use any special ACL
+		features.
+
+		"""
+		if not self.acl_text and not self.def_acl_text: return 1
+		lines = self.acl_text.strip().split('\n')
+		assert len(lines) >= 3, lines
+		return len(lines) == 3 and not self.def_acl_text
+
+	def read_from_rp(self, rp):
+		"""Set self.ACL from an rpath, or None if not supported"""
+		self.acl_text, self.def_acl_text = \
+					   rp.conn.eas_acls.get_acl_text_from_rp(rp)
+
+	def write_to_rp(self, rp):
+		"""Write current access control list to RPath rp"""
+		rp.conn.eas_acls.set_rp_acl(rp, self.acl_text, self.def_acl_text)
+
+def set_rp_acl(rp, acl_text = None, def_acl_text = None):
+	"""Set given rp with ACL that acl_text defines.  rp should be local"""
+	assert rp.conn is Globals.local_connection
+	if acl_text:
+		acl = posix1e.ACL(text=acl_text)
+		assert acl.valid()
+	else: acl = posix1e.ACL()
+	acl.applyto(rp.path)
+	if rp.isdir():
+		if def_acl_text:
+			def_acl = posix1e.ACL(text=def_acl_text)
+			assert def_acl.valid()
+		else: def_acl = posix1e.ACL()
+		def_acl.applyto(rp.path, posix1e.ACL_TYPE_DEFAULT)
+
+def get_acl_text_from_rp(rp):
+	"""Returns (acl_text, def_acl_text) from an rpath.  Call locally"""
+	assert rp.conn is Globals.local_connection
+	try: acl_text = str(posix1e.ACL(file=rp.path))
+	except IOError, exc:
+		if exc[0] == errno.EOPNOTSUPP: acl_text = None
+		else: raise
+	if rp.isdir():
+		try: def_acl_text = str(posix1e.ACL(filedef=rp.path))
+		except IOError, exc:
+			if exc[0] == errno.EOPNOTSUPP: def_acl_text = None
+			else: raise
+	else: def_acl_text = None
+	return (acl_text, def_acl_text)
+
+def acl_compare_rps(rp1, rp2):
+	"""Return true if rp1 and rp2 have same acl information"""
+	acl1 = AccessControlList(rp1.index)
+	acl1.read_from_rp(rp1)
+	acl2 = AccessControlList(rp2.index)
+	acl2.read_from_rp(rp2)
+	return acl1 == acl2
+
+
+def ACL2Record(acl):
+	"""Convert an AccessControlList object into a text record"""
+	start = "# file: %s\n%s" % (acl.get_indexpath(), acl.acl_text)
+	if not acl.def_acl_text: return start
+	default_lines = acl.def_acl_text.strip().split('\n')
+	default_text = '\ndefault:'.join(default_lines)
+	return "%sdefault:%s\n" % (start, default_text)
+
+def Record2ACL(record):
+	"""Convert text record to an AccessControlList object"""
+	lines = record.split('\n')
+	first_line = lines.pop(0)
+	if not first_line.startswith('# file: '):
+		raise metadata.ParsingError("Bad record beginning: "+ first_line)
+	filename = first_line[8:]
+	if filename == '.': index = ()
+	else: index = tuple(filename.split('/'))
+
+	normal_entries = []; default_entries = []
+	for line in lines:
+		if line.startswith('default:'): default_entries.append(line[8:])
+		else: normal_entries.append(line)
+	return AccessControlList(index, acl_text='\n'.join(normal_entries),
+							 def_acl_text='\n'.join(default_entries))
+	
+
+class ACLExtractor(EAExtractor):
+	"""Iterate AccessControlList objects from the ACL information file
+
+	Except for the record_to_object method, we can reuse everything in
+	the EAExtractor class because the file formats are so similar.
+
+	"""
+	record_to_object = staticmethod(Record2ACL)
+
+class AccessControlListFile(metadata.FlatFile):
+	"""Store/retrieve ACLs from extended attributes file"""
+	_prefix = 'access_control_lists'
+	_extractor = ACLExtractor
+	_object_to_record = staticmethod(ACL2Record)
+
+	def join(cls, rorp_iter, rbdir, time, restrict_index):
+		"""Add access control list information to existing rorp_iter"""
+		def helper(rorp_iter, acl_iter):
+			"""Add ACL information in acl_iter to rorp_iter"""
+			collated = rorpiter.CollateIterators(rorp_iter, acl_iter)
+			for rorp, acl in collated:
+				assert rorp, "Missing rorp for index %s" % (acl.index,)
+				if not acl: acl = AccessControlList(rorp.index)
+				rorp.set_acl(acl)
+				yield rorp
+
+		acl_iter = cls.get_objects_at_time(rbdir, time, restrict_index)
+		if acl_iter: return helper(rorp_iter, acl_iter)
+		else:
+			log.Log("Warning: Access Control List file not found", 2)
+			return rorp_iter
+
+static.MakeClass(AccessControlListFile)
+
+
+def GetCombinedMetadataIter(rbdir, time, restrict_index = None,
+							acls = None, eas = None):
+	"""Return iterator of rorps from metadata and related files
+
+	None will be returned if the metadata file is absent.  If acls or
+	eas is true, access control list or extended attribute information
+	will be added.
+
+	"""
+	metadata_iter = metadata.MetadataFile.get_objects_at_time(
+		rbdir, time, restrict_index)
+	if not metadata_iter:
+		log.Log("Warning, metadata file not found.\n"
+				"Metadata will be read from filesystem.", 2)
+		return None
+	if eas:
+		metadata_iter = ExtendedAttributesFile.join(
+			metadata_iter, rbdir, time, restrict_index)
+	if acls:
+		metadata_iter = AccessControlListFile.join(
+			metadata_iter, rbdir, time, restrict_index)
+	return metadata_iter
+