Many changes - added extended attribute support and file system

ability detection


git-svn-id: http://svn.savannah.nongnu.org/svn/rdiff-backup/trunk@334 2b77aa54-bcbc-44c9-a7ec-4f6cf2b41109

1 files changed, 185 insertions, 0 deletions

diff --git a/rdiff-backup/rdiff_backup/eas_acls.py b/rdiff-backup/rdiff_backup/eas_acls.py
new file mode 100644
index 0000000..748d8bb
--- /dev/null
+++ b/rdiff-backup/rdiff_backup/eas_acls.py
@@ -0,0 +1,185 @@
+# 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)