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# Copyright (C) 2008 Lars Wirzenius <liw@iki.fi>
#
# 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.
"""Operation to restore from backup."""
import logging
import os
import stat
import obnam
class UnknownGeneration(obnam.ObnamException):
def __init__(self, gen_id):
self._msg = "Can't find generation %s" % gen_id
class Restore(obnam.Operation):
"""Restore specified files (or all) from a specified generation."""
name = "restore"
def hardlink_key(self, st):
"""Compute key into hardlink lookup table from stat result"""
return "%d/%d" % (st.st_ino, st.st_dev)
def create_filesystem_object(self, hardlinks, full_pathname, inode):
context = self.get_application().get_context()
logging.debug("Creating filesystem object %s" % full_pathname)
stat_component = inode.first_by_kind(obnam.cmp.STAT)
st = obnam.cmp.parse_stat_component(stat_component)
mode = st.st_mode
if st.st_nlink > 1 and not stat.S_ISDIR(mode):
key = self.hardlink_key(st)
if key in hardlinks:
existing_link = hardlinks[key]
os.link(existing_link, full_pathname)
return
else:
hardlinks[key] = full_pathname
if stat.S_ISDIR(mode):
if not os.path.exists(full_pathname):
os.makedirs(full_pathname, 0700)
elif stat.S_ISREG(mode):
basedir = os.path.dirname(full_pathname)
if not os.path.exists(basedir):
os.makedirs(basedir, 0700)
fd = os.open(full_pathname, os.O_WRONLY | os.O_CREAT, 0)
cont_id = inode.first_string_by_kind(obnam.cmp.CONTREF)
if cont_id:
obnam.io.copy_file_contents(context, fd, cont_id)
else:
delta_id = inode.first_string_by_kind(obnam.cmp.DELTAREF)
obnam.io.reconstruct_file_contents(context, fd, delta_id)
os.close(fd)
def restore_requested(self, files, pathname):
"""Return True, if pathname should be restored"""
# If there is no explicit file list, restore everything.
if not files:
return True
# If the pathname is specified explicitly, restore it.
if pathname in files:
return True
# Otherwise, if there's an explicitly specified filename that is a
# prefix of directory parts in the pathname, restore it. That is,
# if files is ["foo/bar"], then restore "foo/bar/baz", but not
# "foo/barbell".
for x in files:
if pathname.startswith(x) and x.endswith(os.sep):
return True
if pathname.startswith(x + os.sep):
return True
# Nope, don't restore it.
return False
def restore_single_item(self, hardlinks, target, pathname, inode):
logging.debug("Restoring %s" % pathname)
if pathname.startswith(os.sep):
pathname = "." + pathname
full_pathname = os.path.join(target, pathname)
self.create_filesystem_object(hardlinks, full_pathname, inode)
return full_pathname
def fix_permissions(self, list):
logging.debug("Fixing permissions")
list.sort()
for full_pathname, inode in list:
obnam.io.set_inode(full_pathname, inode)
def restore_from_filelist(self, target, fl, files):
logging.debug("Restoring files from FILELIST")
list = []
hardlinks = {}
for c in fl.find_by_kind(obnam.cmp.FILE):
pathname = c.first_string_by_kind(obnam.cmp.FILENAME)
if not self.restore_requested(files, pathname):
logging.debug("Restore of %s not requested" % pathname)
continue
full_pathname = self.restore_single_item(hardlinks, target,
pathname, c)
list.append((full_pathname, c))
self.fix_permissions(list)
def restore_from_filegroups(self, target, hardlinks, list, parent,
filegrouprefs, files):
for ref in filegrouprefs:
fg = obnam.io.get_object(self.app.get_context(), ref)
if not fg:
logging.warning("Cannot find FILEGROUP object %s" % ref)
else:
for name in fg.get_names():
if parent:
name2 = os.path.join(parent, name)
if self.restore_requested(files, name2):
file = fg.get_file(name)
full_pathname = self.restore_single_item(hardlinks,
target, name2, file)
list.append((full_pathname, file))
else:
logging.debug("Restore of %s not requested" % name2)
def restore_from_dirs(self, target, hardlinks, list, parent, dirrefs,
files):
for ref in dirrefs:
dir = obnam.io.get_object(self.app.get_context(), ref)
if not dir:
logging.warning("Cannot find DIR object %s" % ref)
else:
name = dir.get_name()
if parent:
name = os.path.join(parent, name)
if self.restore_requested(files, name):
st = dir.first_by_kind(obnam.cmp.STAT)
st = obnam.cmp.parse_stat_component(st)
file = \
obnam.filelist.create_file_component_from_stat(
dir.get_name(), st, None, None, None)
full_pathname = self.restore_single_item(hardlinks,
target, name,
file)
list.append((full_pathname, file))
self.restore_from_filegroups(target, hardlinks, list,
name,
dir.get_filegrouprefs(),
files)
self.restore_from_dirs(target, hardlinks, list, name,
dir.get_dirrefs(), files)
else:
logging.debug("Restore of %s not requested" % name)
def restore_from_dirs_and_filegroups(self, target, gen, files):
hardlinks = {}
list = []
self.restore_from_filegroups(target, hardlinks, list, None,
gen.get_filegrouprefs(), files)
self.restore_from_dirs(target, hardlinks, list,
None, gen.get_dirrefs(), files)
self.fix_permissions(list)
def do_it(self, args):
gen_id = args[0]
files = args[1:]
logging.debug("Restoring generation %s" % gen_id)
logging.debug("Restoring files: %s" % ", ".join(files))
self.app = app = self.get_application()
context = app.get_context()
host = app.load_host()
app.load_maps()
app.load_content_maps()
logging.debug("Getting generation object")
gen = obnam.io.get_object(context, gen_id)
if gen is None:
raise UnknownGeneration(gen_id)
target = context.config.get("backup", "target-dir")
logging.debug("Restoring files under %s" % target)
fl_id = gen.get_filelistref()
if fl_id:
logging.debug("Getting list of files in generation")
fl = obnam.io.get_object(context, fl_id)
if not fl:
logging.warning("Cannot find file list object %s" % fl_id)
else:
self.restore_from_filelist(target, fl, files)
else:
self.restore_from_dirs_and_filegroups(target, gen, files)
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