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#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright 2014-2015 Canonical Limited.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import io
import os
__author__ = 'Jorge Niedbalski R. <jorge.niedbalski@canonical.com>'
class Fstab(io.FileIO):
"""This class extends file in order to implement a file reader/writer
for file `/etc/fstab`
"""
class Entry(object):
"""Entry class represents a non-comment line on the `/etc/fstab` file
"""
def __init__(self, device, mountpoint, filesystem,
options, d=0, p=0):
self.device = device
self.mountpoint = mountpoint
self.filesystem = filesystem
if not options:
options = "defaults"
self.options = options
self.d = int(d)
self.p = int(p)
def __eq__(self, o):
return str(self) == str(o)
def __str__(self):
return "{} {} {} {} {} {}".format(self.device,
self.mountpoint,
self.filesystem,
self.options,
self.d,
self.p)
DEFAULT_PATH = os.path.join(os.path.sep, 'etc', 'fstab')
def __init__(self, path=None):
if path:
self._path = path
else:
self._path = self.DEFAULT_PATH
super(Fstab, self).__init__(self._path, 'rb+')
def _hydrate_entry(self, line):
# NOTE: use split with no arguments to split on any
# whitespace including tabs
return Fstab.Entry(*filter(
lambda x: x not in ('', None),
line.strip("\n").split()))
@property
def entries(self):
self.seek(0)
for line in self.readlines():
line = line.decode('us-ascii')
try:
if line.strip() and not line.strip().startswith("#"):
yield self._hydrate_entry(line)
except ValueError:
pass
def get_entry_by_attr(self, attr, value):
for entry in self.entries:
e_attr = getattr(entry, attr)
if e_attr == value:
return entry
return None
def add_entry(self, entry):
if self.get_entry_by_attr('device', entry.device):
return False
self.write((str(entry) + '\n').encode('us-ascii'))
self.truncate()
return entry
def remove_entry(self, entry):
self.seek(0)
lines = [l.decode('us-ascii') for l in self.readlines()]
found = False
for index, line in enumerate(lines):
if line.strip() and not line.strip().startswith("#"):
if self._hydrate_entry(line) == entry:
found = True
break
if not found:
return False
lines.remove(line)
self.seek(0)
self.write(''.join(lines).encode('us-ascii'))
self.truncate()
return True
@classmethod
def remove_by_mountpoint(cls, mountpoint, path=None):
fstab = cls(path=path)
entry = fstab.get_entry_by_attr('mountpoint', mountpoint)
if entry:
return fstab.remove_entry(entry)
return False
@classmethod
def add(cls, device, mountpoint, filesystem, options=None, path=None):
return cls(path=path).add_entry(Fstab.Entry(device,
mountpoint, filesystem,
options=options))
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