nova/nova/privsep/path.py

113 lines
3.3 KiB
Python

# Copyright 2016 Red Hat, Inc
# Copyright 2017 Rackspace Australia
#
# 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.
"""Routines that bypass file-system checks."""
import errno
import os
import shutil
from oslo_utils import fileutils
from nova import exception
import nova.privsep
@nova.privsep.sys_admin_pctxt.entrypoint
def writefile(path, mode, content):
if not os.path.exists(os.path.dirname(path)):
raise exception.FileNotFound(file_path=path)
with open(path, mode) as f:
f.write(content)
@nova.privsep.sys_admin_pctxt.entrypoint
def chown(
path: str, uid: int = -1, gid: int = -1, recursive: bool = False,
) -> None:
if not os.path.exists(path):
raise exception.FileNotFound(file_path=path)
if not recursive or os.path.isfile(path):
return os.chown(path, uid, gid)
for root, dirs, files in os.walk(path):
os.chown(root, uid, gid)
for item in dirs:
os.chown(os.path.join(root, item), uid, gid)
for item in files:
os.chown(os.path.join(root, item), uid, gid)
@nova.privsep.sys_admin_pctxt.entrypoint
def makedirs(path):
fileutils.ensure_tree(path)
@nova.privsep.sys_admin_pctxt.entrypoint
def chmod(path, mode):
if not os.path.exists(path):
raise exception.FileNotFound(file_path=path)
os.chmod(path, mode)
@nova.privsep.sys_admin_pctxt.entrypoint
def move_tree(source_path: str, dest_path: str) -> None:
shutil.move(source_path, dest_path)
@nova.privsep.sys_admin_pctxt.entrypoint
def utime(path):
if not os.path.exists(path):
raise exception.FileNotFound(file_path=path)
# NOTE(mikal): the old version of this used execute(touch, ...), which
# would apparently fail on shared storage when multiple instances were
# being launched at the same time. If we see failures here, we might need
# to wrap this in a try / except.
os.utime(path, None)
@nova.privsep.sys_admin_pctxt.entrypoint
def rmdir(path):
if not os.path.exists(path):
raise exception.FileNotFound(file_path=path)
os.rmdir(path)
@nova.privsep.sys_admin_pctxt.entrypoint
def last_bytes(path, num):
"""Return num bytes from the end of the file, and remaining byte count.
:param path: The file to read
:param num: The number of bytes to return
:returns: (data, remaining)
"""
with open(path, 'rb') as f:
try:
f.seek(-num, os.SEEK_END)
except IOError as e:
# seek() fails with EINVAL when trying to go before the start of
# the file. It means that num is larger than the file size, so
# just go to the start.
if e.errno == errno.EINVAL:
f.seek(0, os.SEEK_SET)
else:
raise
remaining = f.tell()
return (f.read(), remaining)