126 lines
3.6 KiB
Python
126 lines
3.6 KiB
Python
# Copyright 2016 Red Hat, Inc
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# Copyright 2017 Rackspace Australia
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""Routines that bypass file-system checks."""
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import errno
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import os
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from oslo_utils import fileutils
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from nova import exception
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import nova.privsep
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@nova.privsep.sys_admin_pctxt.entrypoint
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def readfile(path):
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if not os.path.exists(path):
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raise exception.FileNotFound(file_path=path)
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with open(path, 'r') as f:
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return f.read()
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@nova.privsep.sys_admin_pctxt.entrypoint
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def writefile(path, mode, content):
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if not os.path.exists(os.path.dirname(path)):
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raise exception.FileNotFound(file_path=path)
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with open(path, mode) as f:
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f.write(content)
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@nova.privsep.sys_admin_pctxt.entrypoint
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def readlink(path):
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if not os.path.exists(path):
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raise exception.FileNotFound(file_path=path)
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return os.readlink(path)
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@nova.privsep.sys_admin_pctxt.entrypoint
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def chown(path, uid=-1, gid=-1):
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if not os.path.exists(path):
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raise exception.FileNotFound(file_path=path)
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return os.chown(path, uid, gid)
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@nova.privsep.sys_admin_pctxt.entrypoint
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def makedirs(path):
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fileutils.ensure_tree(path)
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@nova.privsep.sys_admin_pctxt.entrypoint
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def chmod(path, mode):
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if not os.path.exists(path):
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raise exception.FileNotFound(file_path=path)
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os.chmod(path, mode)
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@nova.privsep.sys_admin_pctxt.entrypoint
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def utime(path):
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if not os.path.exists(path):
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raise exception.FileNotFound(file_path=path)
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# NOTE(mikal): the old version of this used execute(touch, ...), which
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# would apparently fail on shared storage when multiple instances were
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# being launched at the same time. If we see failures here, we might need
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# to wrap this in a try / except.
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os.utime(path, None)
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@nova.privsep.sys_admin_pctxt.entrypoint
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def rmdir(path):
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if not os.path.exists(path):
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raise exception.FileNotFound(file_path=path)
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os.rmdir(path)
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class path(object):
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@staticmethod
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@nova.privsep.sys_admin_pctxt.entrypoint
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def exists(path):
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return os.path.exists(path)
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@nova.privsep.sys_admin_pctxt.entrypoint
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def last_bytes(path, num):
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# NOTE(mikal): this is implemented in this contrived manner because you
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# can't mock a decorator in python (they're loaded at file parse time,
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# and the mock happens later).
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with open(path, 'rb') as f:
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return _last_bytes_inner(f, num)
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def _last_bytes_inner(file_like_object, num):
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"""Return num bytes from the end of the file, and remaining byte count.
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:param file_like_object: The file to read
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:param num: The number of bytes to return
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:returns: (data, remaining)
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"""
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try:
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file_like_object.seek(-num, os.SEEK_END)
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except IOError as e:
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# seek() fails with EINVAL when trying to go before the start of
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# the file. It means that num is larger than the file size, so
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# just go to the start.
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if e.errno == errno.EINVAL:
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file_like_object.seek(0, os.SEEK_SET)
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else:
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raise
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remaining = file_like_object.tell()
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return (file_like_object.read(), remaining)
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