root / lib / utils / io.py @ 1cc324f0
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#
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#
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# Copyright (C) 2006, 2007, 2010, 2011, 2012 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""Utility functions for I/O.
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"""
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import os |
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import logging |
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import shutil |
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import tempfile |
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import errno |
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import time |
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import stat |
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import grp |
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import pwd |
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from ganeti import errors |
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from ganeti import constants |
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from ganeti import pathutils |
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from ganeti.utils import filelock |
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#: Directory used by fsck(8) to store recovered data, usually at a file
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#: system's root directory
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_LOST_AND_FOUND = "lost+found"
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# Possible values for keep_perms in WriteFile()
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KP_NEVER = 0
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KP_ALWAYS = 1
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KP_IF_EXISTS = 2
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KEEP_PERMS_VALUES = [ |
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KP_NEVER, |
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KP_ALWAYS, |
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KP_IF_EXISTS, |
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] |
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def ErrnoOrStr(err): |
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"""Format an EnvironmentError exception.
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If the L{err} argument has an errno attribute, it will be looked up
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and converted into a textual C{E...} description. Otherwise the
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string representation of the error will be returned.
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@type err: L{EnvironmentError}
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@param err: the exception to format
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"""
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if hasattr(err, "errno"): |
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detail = errno.errorcode[err.errno] |
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else:
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detail = str(err)
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return detail
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class FileStatHelper: |
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"""Helper to store file handle's C{fstat}.
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Useful in combination with L{ReadFile}'s C{preread} parameter.
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"""
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def __init__(self): |
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"""Initializes this class.
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"""
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self.st = None |
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def __call__(self, fh): |
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"""Calls C{fstat} on file handle.
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"""
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self.st = os.fstat(fh.fileno())
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def ReadFile(file_name, size=-1, preread=None): |
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"""Reads a file.
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@type size: int
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@param size: Read at most size bytes (if negative, entire file)
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@type preread: callable receiving file handle as single parameter
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@param preread: Function called before file is read
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@rtype: str
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@return: the (possibly partial) content of the file
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"""
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f = open(file_name, "r") |
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try:
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if preread:
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preread(f) |
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return f.read(size)
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finally:
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f.close() |
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def WriteFile(file_name, fn=None, data=None, |
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mode=None, uid=-1, gid=-1, |
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atime=None, mtime=None, close=True, |
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dry_run=False, backup=False, |
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prewrite=None, postwrite=None, keep_perms=KP_NEVER): |
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"""(Over)write a file atomically.
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The file_name and either fn (a function taking one argument, the
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file descriptor, and which should write the data to it) or data (the
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contents of the file) must be passed. The other arguments are
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optional and allow setting the file mode, owner and group, and the
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mtime/atime of the file.
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If the function doesn't raise an exception, it has succeeded and the
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target file has the new contents. If the function has raised an
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exception, an existing target file should be unmodified and the
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temporary file should be removed.
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@type file_name: str
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@param file_name: the target filename
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@type fn: callable
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@param fn: content writing function, called with
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file descriptor as parameter
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@type data: str
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@param data: contents of the file
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@type mode: int
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@param mode: file mode
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@type uid: int
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@param uid: the owner of the file
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@type gid: int
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@param gid: the group of the file
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@type atime: int
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@param atime: a custom access time to be set on the file
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@type mtime: int
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@param mtime: a custom modification time to be set on the file
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@type close: boolean
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@param close: whether to close file after writing it
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@type prewrite: callable
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@param prewrite: function to be called before writing content
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@type postwrite: callable
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@param postwrite: function to be called after writing content
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@type keep_perms: members of L{KEEP_PERMS_VALUES}
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@param keep_perms: if L{KP_NEVER} (default), owner, group, and mode are
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taken from the other parameters; if L{KP_ALWAYS}, owner, group, and
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mode are copied from the existing file; if L{KP_IF_EXISTS}, owner,
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group, and mode are taken from the file, and if the file doesn't
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exist, they are taken from the other parameters. It is an error to
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pass L{KP_ALWAYS} when the file doesn't exist or when C{uid}, C{gid},
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or C{mode} are set to non-default values.
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@rtype: None or int
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@return: None if the 'close' parameter evaluates to True,
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otherwise the file descriptor
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@raise errors.ProgrammerError: if any of the arguments are not valid
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"""
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if not os.path.isabs(file_name): |
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raise errors.ProgrammerError("Path passed to WriteFile is not" |
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" absolute: '%s'" % file_name)
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if [fn, data].count(None) != 1: |
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raise errors.ProgrammerError("fn or data required") |
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if [atime, mtime].count(None) == 1: |
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raise errors.ProgrammerError("Both atime and mtime must be either" |
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" set or None")
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if not keep_perms in KEEP_PERMS_VALUES: |
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raise errors.ProgrammerError("Invalid value for keep_perms: %s" % |
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keep_perms) |
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if keep_perms == KP_ALWAYS and (uid != -1 or gid != -1 or mode is not None): |
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raise errors.ProgrammerError("When keep_perms==KP_ALWAYS, 'uid', 'gid'," |
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" and 'mode' cannot be set")
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if backup and not dry_run and os.path.isfile(file_name): |
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CreateBackup(file_name) |
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if keep_perms == KP_ALWAYS or keep_perms == KP_IF_EXISTS: |
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# os.stat() raises an exception if the file doesn't exist
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try:
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file_stat = os.stat(file_name) |
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mode = stat.S_IMODE(file_stat.st_mode) |
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uid = file_stat.st_uid |
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gid = file_stat.st_gid |
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except OSError: |
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if keep_perms == KP_ALWAYS:
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raise
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# else: if keeep_perms == KP_IF_EXISTS it's ok if the file doesn't exist
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# Whether temporary file needs to be removed (e.g. if any error occurs)
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do_remove = True
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# Function result
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result = None
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(dir_name, base_name) = os.path.split(file_name) |
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(fd, new_name) = tempfile.mkstemp(suffix=".new", prefix=base_name,
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dir=dir_name) |
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try:
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try:
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if uid != -1 or gid != -1: |
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os.chown(new_name, uid, gid) |
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if mode:
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os.chmod(new_name, mode) |
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if callable(prewrite): |
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prewrite(fd) |
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if data is not None: |
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if isinstance(data, unicode): |
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data = data.encode() |
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assert isinstance(data, str) |
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to_write = len(data)
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offset = 0
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while offset < to_write:
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written = os.write(fd, buffer(data, offset))
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assert written >= 0 |
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assert written <= to_write - offset
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offset += written |
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assert offset == to_write
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else:
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fn(fd) |
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if callable(postwrite): |
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postwrite(fd) |
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os.fsync(fd) |
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if atime is not None and mtime is not None: |
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os.utime(new_name, (atime, mtime)) |
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finally:
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# Close file unless the file descriptor should be returned
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if close:
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os.close(fd) |
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else:
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result = fd |
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# Rename file to destination name
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if not dry_run: |
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os.rename(new_name, file_name) |
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# Successful, no need to remove anymore
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do_remove = False
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finally:
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if do_remove:
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RemoveFile(new_name) |
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return result
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def GetFileID(path=None, fd=None): |
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"""Returns the file 'id', i.e. the dev/inode and mtime information.
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Either the path to the file or the fd must be given.
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@param path: the file path
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@param fd: a file descriptor
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@return: a tuple of (device number, inode number, mtime)
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"""
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if [path, fd].count(None) != 1: |
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raise errors.ProgrammerError("One and only one of fd/path must be given") |
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if fd is None: |
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st = os.stat(path) |
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else:
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st = os.fstat(fd) |
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return (st.st_dev, st.st_ino, st.st_mtime)
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def VerifyFileID(fi_disk, fi_ours): |
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"""Verifies that two file IDs are matching.
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Differences in the inode/device are not accepted, but and older
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timestamp for fi_disk is accepted.
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@param fi_disk: tuple (dev, inode, mtime) representing the actual
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file data
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@param fi_ours: tuple (dev, inode, mtime) representing the last
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written file data
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@rtype: boolean
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"""
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(d1, i1, m1) = fi_disk |
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(d2, i2, m2) = fi_ours |
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return (d1, i1) == (d2, i2) and m1 <= m2 |
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def SafeWriteFile(file_name, file_id, **kwargs): |
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"""Wraper over L{WriteFile} that locks the target file.
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By keeping the target file locked during WriteFile, we ensure that
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cooperating writers will safely serialise access to the file.
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@type file_name: str
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@param file_name: the target filename
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@type file_id: tuple
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@param file_id: a result from L{GetFileID}
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"""
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fd = os.open(file_name, os.O_RDONLY | os.O_CREAT) |
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try:
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filelock.LockFile(fd) |
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if file_id is not None: |
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disk_id = GetFileID(fd=fd) |
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if not VerifyFileID(disk_id, file_id): |
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raise errors.LockError("Cannot overwrite file %s, it has been modified" |
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" since last written" % file_name)
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return WriteFile(file_name, **kwargs)
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finally:
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os.close(fd) |
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def ReadOneLineFile(file_name, strict=False): |
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"""Return the first non-empty line from a file.
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@type strict: boolean
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@param strict: if True, abort if the file has more than one
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non-empty line
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"""
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file_lines = ReadFile(file_name).splitlines() |
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full_lines = filter(bool, file_lines) |
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if not file_lines or not full_lines: |
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raise errors.GenericError("No data in one-liner file %s" % file_name) |
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elif strict and len(full_lines) > 1: |
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raise errors.GenericError("Too many lines in one-liner file %s" % |
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file_name) |
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return full_lines[0] |
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def RemoveFile(filename): |
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"""Remove a file ignoring some errors.
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Remove a file, ignoring non-existing ones or directories. Other
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errors are passed.
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@type filename: str
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@param filename: the file to be removed
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"""
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try:
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os.unlink(filename) |
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except OSError, err: |
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if err.errno not in (errno.ENOENT, errno.EISDIR): |
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raise
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def RemoveDir(dirname): |
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"""Remove an empty directory.
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Remove a directory, ignoring non-existing ones.
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Other errors are passed. This includes the case,
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where the directory is not empty, so it can't be removed.
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@type dirname: str
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@param dirname: the empty directory to be removed
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"""
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try:
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os.rmdir(dirname) |
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except OSError, err: |
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if err.errno != errno.ENOENT:
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raise
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def RenameFile(old, new, mkdir=False, mkdir_mode=0750, dir_uid=None, |
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dir_gid=None):
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"""Renames a file.
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This just creates the very least directory if it does not exist and C{mkdir}
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is set to true.
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@type old: string
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@param old: Original path
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@type new: string
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@param new: New path
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@type mkdir: bool
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@param mkdir: Whether to create target directory if it doesn't exist
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@type mkdir_mode: int
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@param mkdir_mode: Mode for newly created directories
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@type dir_uid: int
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@param dir_uid: The uid for the (if fresh created) dir
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@type dir_gid: int
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@param dir_gid: The gid for the (if fresh created) dir
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"""
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try:
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return os.rename(old, new)
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except OSError, err: |
401 |
# In at least one use case of this function, the job queue, directory
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# creation is very rare. Checking for the directory before renaming is not
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# as efficient.
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if mkdir and err.errno == errno.ENOENT: |
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# Create directory and try again
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dir_path = os.path.dirname(new) |
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MakeDirWithPerm(dir_path, mkdir_mode, dir_uid, dir_gid) |
408 |
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return os.rename(old, new)
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raise
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def EnforcePermission(path, mode, uid=None, gid=None, must_exist=True, |
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_chmod_fn=os.chmod, _chown_fn=os.chown, _stat_fn=os.stat): |
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"""Enforces that given path has given permissions.
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@param path: The path to the file
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@param mode: The mode of the file
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@param uid: The uid of the owner of this file
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@param gid: The gid of the owner of this file
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@param must_exist: Specifies if non-existance of path will be an error
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@param _chmod_fn: chmod function to use (unittest only)
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@param _chown_fn: chown function to use (unittest only)
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|
426 |
"""
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logging.debug("Checking %s", path)
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# chown takes -1 if you want to keep one part of the ownership, however
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# None is Python standard for that. So we remap them here.
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if uid is None: |
432 |
uid = -1
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if gid is None: |
434 |
gid = -1
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|
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try:
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st = _stat_fn(path) |
438 |
|
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fmode = stat.S_IMODE(st[stat.ST_MODE]) |
440 |
if fmode != mode:
|
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logging.debug("Changing mode of %s from %#o to %#o", path, fmode, mode)
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_chmod_fn(path, mode) |
443 |
|
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if max(uid, gid) > -1: |
445 |
fuid = st[stat.ST_UID] |
446 |
fgid = st[stat.ST_GID] |
447 |
if fuid != uid or fgid != gid: |
448 |
logging.debug("Changing owner of %s from UID %s/GID %s to"
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" UID %s/GID %s", path, fuid, fgid, uid, gid)
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_chown_fn(path, uid, gid) |
451 |
except EnvironmentError, err: |
452 |
if err.errno == errno.ENOENT:
|
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if must_exist:
|
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raise errors.GenericError("Path %s should exist, but does not" % path) |
455 |
else:
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raise errors.GenericError("Error while changing permissions on %s: %s" % |
457 |
(path, err)) |
458 |
|
459 |
|
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def MakeDirWithPerm(path, mode, uid, gid, _lstat_fn=os.lstat, |
461 |
_mkdir_fn=os.mkdir, _perm_fn=EnforcePermission): |
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"""Enforces that given path is a dir and has given mode, uid and gid set.
|
463 |
|
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@param path: The path to the file
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@param mode: The mode of the file
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@param uid: The uid of the owner of this file
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@param gid: The gid of the owner of this file
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@param _lstat_fn: Stat function to use (unittest only)
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@param _mkdir_fn: mkdir function to use (unittest only)
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@param _perm_fn: permission setter function to use (unittest only)
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|
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"""
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473 |
logging.debug("Checking directory %s", path)
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try:
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# We don't want to follow symlinks
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st = _lstat_fn(path) |
477 |
except EnvironmentError, err: |
478 |
if err.errno != errno.ENOENT:
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raise errors.GenericError("stat(2) on %s failed: %s" % (path, err)) |
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_mkdir_fn(path) |
481 |
else:
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482 |
if not stat.S_ISDIR(st[stat.ST_MODE]): |
483 |
raise errors.GenericError(("Path %s is expected to be a directory, but " |
484 |
"isn't") % path)
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485 |
|
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_perm_fn(path, mode, uid=uid, gid=gid) |
487 |
|
488 |
|
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def Makedirs(path, mode=0750): |
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"""Super-mkdir; create a leaf directory and all intermediate ones.
|
491 |
|
492 |
This is a wrapper around C{os.makedirs} adding error handling not implemented
|
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before Python 2.5.
|
494 |
|
495 |
"""
|
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try:
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os.makedirs(path, mode) |
498 |
except OSError, err: |
499 |
# Ignore EEXIST. This is only handled in os.makedirs as included in
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500 |
# Python 2.5 and above.
|
501 |
if err.errno != errno.EEXIST or not os.path.exists(path): |
502 |
raise
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503 |
|
504 |
|
505 |
def TimestampForFilename(): |
506 |
"""Returns the current time formatted for filenames.
|
507 |
|
508 |
The format doesn't contain colons as some shells and applications treat them
|
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as separators. Uses the local timezone.
|
510 |
|
511 |
"""
|
512 |
return time.strftime("%Y-%m-%d_%H_%M_%S") |
513 |
|
514 |
|
515 |
def CreateBackup(file_name): |
516 |
"""Creates a backup of a file.
|
517 |
|
518 |
@type file_name: str
|
519 |
@param file_name: file to be backed up
|
520 |
@rtype: str
|
521 |
@return: the path to the newly created backup
|
522 |
@raise errors.ProgrammerError: for invalid file names
|
523 |
|
524 |
"""
|
525 |
if not os.path.isfile(file_name): |
526 |
raise errors.ProgrammerError("Can't make a backup of a non-file '%s'" % |
527 |
file_name) |
528 |
|
529 |
prefix = ("%s.backup-%s." %
|
530 |
(os.path.basename(file_name), TimestampForFilename())) |
531 |
dir_name = os.path.dirname(file_name) |
532 |
|
533 |
fsrc = open(file_name, "rb") |
534 |
try:
|
535 |
(fd, backup_name) = tempfile.mkstemp(prefix=prefix, dir=dir_name) |
536 |
fdst = os.fdopen(fd, "wb")
|
537 |
try:
|
538 |
logging.debug("Backing up %s at %s", file_name, backup_name)
|
539 |
shutil.copyfileobj(fsrc, fdst) |
540 |
finally:
|
541 |
fdst.close() |
542 |
finally:
|
543 |
fsrc.close() |
544 |
|
545 |
return backup_name
|
546 |
|
547 |
|
548 |
def ListVisibleFiles(path, _is_mountpoint=os.path.ismount): |
549 |
"""Returns a list of visible files in a directory.
|
550 |
|
551 |
@type path: str
|
552 |
@param path: the directory to enumerate
|
553 |
@rtype: list
|
554 |
@return: the list of all files not starting with a dot
|
555 |
@raise ProgrammerError: if L{path} is not an absolue and normalized path
|
556 |
|
557 |
"""
|
558 |
if not IsNormAbsPath(path): |
559 |
raise errors.ProgrammerError("Path passed to ListVisibleFiles is not" |
560 |
" absolute/normalized: '%s'" % path)
|
561 |
|
562 |
mountpoint = _is_mountpoint(path) |
563 |
|
564 |
def fn(name): |
565 |
"""File name filter.
|
566 |
|
567 |
Ignores files starting with a dot (".") as by Unix convention they're
|
568 |
considered hidden. The "lost+found" directory found at the root of some
|
569 |
filesystems is also hidden.
|
570 |
|
571 |
"""
|
572 |
return not (name.startswith(".") or |
573 |
(mountpoint and name == _LOST_AND_FOUND and |
574 |
os.path.isdir(os.path.join(path, name)))) |
575 |
|
576 |
return filter(fn, os.listdir(path)) |
577 |
|
578 |
|
579 |
def EnsureDirs(dirs): |
580 |
"""Make required directories, if they don't exist.
|
581 |
|
582 |
@param dirs: list of tuples (dir_name, dir_mode)
|
583 |
@type dirs: list of (string, integer)
|
584 |
|
585 |
"""
|
586 |
for dir_name, dir_mode in dirs: |
587 |
try:
|
588 |
os.mkdir(dir_name, dir_mode) |
589 |
except EnvironmentError, err: |
590 |
if err.errno != errno.EEXIST:
|
591 |
raise errors.GenericError("Cannot create needed directory" |
592 |
" '%s': %s" % (dir_name, err))
|
593 |
try:
|
594 |
os.chmod(dir_name, dir_mode) |
595 |
except EnvironmentError, err: |
596 |
raise errors.GenericError("Cannot change directory permissions on" |
597 |
" '%s': %s" % (dir_name, err))
|
598 |
if not os.path.isdir(dir_name): |
599 |
raise errors.GenericError("%s is not a directory" % dir_name) |
600 |
|
601 |
|
602 |
def FindFile(name, search_path, test=os.path.exists): |
603 |
"""Look for a filesystem object in a given path.
|
604 |
|
605 |
This is an abstract method to search for filesystem object (files,
|
606 |
dirs) under a given search path.
|
607 |
|
608 |
@type name: str
|
609 |
@param name: the name to look for
|
610 |
@type search_path: str
|
611 |
@param search_path: location to start at
|
612 |
@type test: callable
|
613 |
@param test: a function taking one argument that should return True
|
614 |
if the a given object is valid; the default value is
|
615 |
os.path.exists, causing only existing files to be returned
|
616 |
@rtype: str or None
|
617 |
@return: full path to the object if found, None otherwise
|
618 |
|
619 |
"""
|
620 |
# validate the filename mask
|
621 |
if constants.EXT_PLUGIN_MASK.match(name) is None: |
622 |
logging.critical("Invalid value passed for external script name: '%s'",
|
623 |
name) |
624 |
return None |
625 |
|
626 |
for dir_name in search_path: |
627 |
# FIXME: investigate switch to PathJoin
|
628 |
item_name = os.path.sep.join([dir_name, name]) |
629 |
# check the user test and that we're indeed resolving to the given
|
630 |
# basename
|
631 |
if test(item_name) and os.path.basename(item_name) == name: |
632 |
return item_name
|
633 |
return None |
634 |
|
635 |
|
636 |
def IsNormAbsPath(path): |
637 |
"""Check whether a path is absolute and also normalized
|
638 |
|
639 |
This avoids things like /dir/../../other/path to be valid.
|
640 |
|
641 |
"""
|
642 |
return os.path.normpath(path) == path and os.path.isabs(path) |
643 |
|
644 |
|
645 |
def IsBelowDir(root, other_path): |
646 |
"""Check whether a path is below a root dir.
|
647 |
|
648 |
This works around the nasty byte-byte comparison of commonprefix.
|
649 |
|
650 |
"""
|
651 |
if not (os.path.isabs(root) and os.path.isabs(other_path)): |
652 |
raise ValueError("Provided paths '%s' and '%s' are not absolute" % |
653 |
(root, other_path)) |
654 |
|
655 |
norm_other = os.path.normpath(other_path) |
656 |
|
657 |
if norm_other == os.sep:
|
658 |
# The root directory can never be below another path
|
659 |
return False |
660 |
|
661 |
norm_root = os.path.normpath(root) |
662 |
|
663 |
if norm_root == os.sep:
|
664 |
# This is the root directory, no need to add another slash
|
665 |
prepared_root = norm_root |
666 |
else:
|
667 |
prepared_root = "%s%s" % (norm_root, os.sep)
|
668 |
|
669 |
return os.path.commonprefix([prepared_root, norm_other]) == prepared_root
|
670 |
|
671 |
|
672 |
def PathJoin(*args): |
673 |
"""Safe-join a list of path components.
|
674 |
|
675 |
Requirements:
|
676 |
- the first argument must be an absolute path
|
677 |
- no component in the path must have backtracking (e.g. /../),
|
678 |
since we check for normalization at the end
|
679 |
|
680 |
@param args: the path components to be joined
|
681 |
@raise ValueError: for invalid paths
|
682 |
|
683 |
"""
|
684 |
# ensure we're having at least one path passed in
|
685 |
assert args
|
686 |
# ensure the first component is an absolute and normalized path name
|
687 |
root = args[0]
|
688 |
if not IsNormAbsPath(root): |
689 |
raise ValueError("Invalid parameter to PathJoin: '%s'" % str(args[0])) |
690 |
result = os.path.join(*args) |
691 |
# ensure that the whole path is normalized
|
692 |
if not IsNormAbsPath(result): |
693 |
raise ValueError("Invalid parameters to PathJoin: '%s'" % str(args)) |
694 |
# check that we're still under the original prefix
|
695 |
if not IsBelowDir(root, result): |
696 |
raise ValueError("Error: path joining resulted in different prefix" |
697 |
" (%s != %s)" % (result, root))
|
698 |
return result
|
699 |
|
700 |
|
701 |
def TailFile(fname, lines=20): |
702 |
"""Return the last lines from a file.
|
703 |
|
704 |
@note: this function will only read and parse the last 4KB of
|
705 |
the file; if the lines are very long, it could be that less
|
706 |
than the requested number of lines are returned
|
707 |
|
708 |
@param fname: the file name
|
709 |
@type lines: int
|
710 |
@param lines: the (maximum) number of lines to return
|
711 |
|
712 |
"""
|
713 |
fd = open(fname, "r") |
714 |
try:
|
715 |
fd.seek(0, 2) |
716 |
pos = fd.tell() |
717 |
pos = max(0, pos - 4096) |
718 |
fd.seek(pos, 0)
|
719 |
raw_data = fd.read() |
720 |
finally:
|
721 |
fd.close() |
722 |
|
723 |
rows = raw_data.splitlines() |
724 |
return rows[-lines:]
|
725 |
|
726 |
|
727 |
def BytesToMebibyte(value): |
728 |
"""Converts bytes to mebibytes.
|
729 |
|
730 |
@type value: int
|
731 |
@param value: Value in bytes
|
732 |
@rtype: int
|
733 |
@return: Value in mebibytes
|
734 |
|
735 |
"""
|
736 |
return int(round(value / (1024.0 * 1024.0), 0)) |
737 |
|
738 |
|
739 |
def CalculateDirectorySize(path): |
740 |
"""Calculates the size of a directory recursively.
|
741 |
|
742 |
@type path: string
|
743 |
@param path: Path to directory
|
744 |
@rtype: int
|
745 |
@return: Size in mebibytes
|
746 |
|
747 |
"""
|
748 |
size = 0
|
749 |
|
750 |
for (curpath, _, files) in os.walk(path): |
751 |
for filename in files: |
752 |
st = os.lstat(PathJoin(curpath, filename)) |
753 |
size += st.st_size |
754 |
|
755 |
return BytesToMebibyte(size)
|
756 |
|
757 |
|
758 |
def GetFilesystemStats(path): |
759 |
"""Returns the total and free space on a filesystem.
|
760 |
|
761 |
@type path: string
|
762 |
@param path: Path on filesystem to be examined
|
763 |
@rtype: int
|
764 |
@return: tuple of (Total space, Free space) in mebibytes
|
765 |
|
766 |
"""
|
767 |
st = os.statvfs(path) |
768 |
|
769 |
fsize = BytesToMebibyte(st.f_bavail * st.f_frsize) |
770 |
tsize = BytesToMebibyte(st.f_blocks * st.f_frsize) |
771 |
return (tsize, fsize)
|
772 |
|
773 |
|
774 |
def ReadPidFile(pidfile): |
775 |
"""Read a pid from a file.
|
776 |
|
777 |
@type pidfile: string
|
778 |
@param pidfile: path to the file containing the pid
|
779 |
@rtype: int
|
780 |
@return: The process id, if the file exists and contains a valid PID,
|
781 |
otherwise 0
|
782 |
|
783 |
"""
|
784 |
try:
|
785 |
raw_data = ReadOneLineFile(pidfile) |
786 |
except EnvironmentError, err: |
787 |
if err.errno != errno.ENOENT:
|
788 |
logging.exception("Can't read pid file")
|
789 |
return 0 |
790 |
|
791 |
return _ParsePidFileContents(raw_data)
|
792 |
|
793 |
|
794 |
def _ParsePidFileContents(data): |
795 |
"""Tries to extract a process ID from a PID file's content.
|
796 |
|
797 |
@type data: string
|
798 |
@rtype: int
|
799 |
@return: Zero if nothing could be read, PID otherwise
|
800 |
|
801 |
"""
|
802 |
try:
|
803 |
pid = int(data)
|
804 |
except (TypeError, ValueError): |
805 |
logging.info("Can't parse pid file contents", exc_info=True) |
806 |
return 0 |
807 |
else:
|
808 |
return pid
|
809 |
|
810 |
|
811 |
def ReadLockedPidFile(path): |
812 |
"""Reads a locked PID file.
|
813 |
|
814 |
This can be used together with L{utils.process.StartDaemon}.
|
815 |
|
816 |
@type path: string
|
817 |
@param path: Path to PID file
|
818 |
@return: PID as integer or, if file was unlocked or couldn't be opened, None
|
819 |
|
820 |
"""
|
821 |
try:
|
822 |
fd = os.open(path, os.O_RDONLY) |
823 |
except EnvironmentError, err: |
824 |
if err.errno == errno.ENOENT:
|
825 |
# PID file doesn't exist
|
826 |
return None |
827 |
raise
|
828 |
|
829 |
try:
|
830 |
try:
|
831 |
# Try to acquire lock
|
832 |
filelock.LockFile(fd) |
833 |
except errors.LockError:
|
834 |
# Couldn't lock, daemon is running
|
835 |
return int(os.read(fd, 100)) |
836 |
finally:
|
837 |
os.close(fd) |
838 |
|
839 |
return None |
840 |
|
841 |
|
842 |
def _SplitSshKey(key): |
843 |
"""Splits a line for SSH's C{authorized_keys} file.
|
844 |
|
845 |
If the line has no options (e.g. no C{command="..."}), only the significant
|
846 |
parts, the key type and its hash, are used. Otherwise the whole line is used
|
847 |
(split at whitespace).
|
848 |
|
849 |
@type key: string
|
850 |
@param key: Key line
|
851 |
@rtype: tuple
|
852 |
|
853 |
"""
|
854 |
parts = key.split() |
855 |
|
856 |
if parts and parts[0] in constants.SSHAK_ALL: |
857 |
# If the key has no options in front of it, we only want the significant
|
858 |
# fields
|
859 |
return (False, parts[:2]) |
860 |
else:
|
861 |
# Can't properly split the line, so use everything
|
862 |
return (True, parts) |
863 |
|
864 |
|
865 |
def AddAuthorizedKey(file_obj, key): |
866 |
"""Adds an SSH public key to an authorized_keys file.
|
867 |
|
868 |
@type file_obj: str or file handle
|
869 |
@param file_obj: path to authorized_keys file
|
870 |
@type key: str
|
871 |
@param key: string containing key
|
872 |
|
873 |
"""
|
874 |
key_fields = _SplitSshKey(key) |
875 |
|
876 |
if isinstance(file_obj, basestring): |
877 |
f = open(file_obj, "a+") |
878 |
else:
|
879 |
f = file_obj |
880 |
|
881 |
try:
|
882 |
nl = True
|
883 |
for line in f: |
884 |
# Ignore whitespace changes
|
885 |
if _SplitSshKey(line) == key_fields:
|
886 |
break
|
887 |
nl = line.endswith("\n")
|
888 |
else:
|
889 |
if not nl: |
890 |
f.write("\n")
|
891 |
f.write(key.rstrip("\r\n"))
|
892 |
f.write("\n")
|
893 |
f.flush() |
894 |
finally:
|
895 |
f.close() |
896 |
|
897 |
|
898 |
def RemoveAuthorizedKey(file_name, key): |
899 |
"""Removes an SSH public key from an authorized_keys file.
|
900 |
|
901 |
@type file_name: str
|
902 |
@param file_name: path to authorized_keys file
|
903 |
@type key: str
|
904 |
@param key: string containing key
|
905 |
|
906 |
"""
|
907 |
key_fields = _SplitSshKey(key) |
908 |
|
909 |
fd, tmpname = tempfile.mkstemp(dir=os.path.dirname(file_name)) |
910 |
try:
|
911 |
out = os.fdopen(fd, "w")
|
912 |
try:
|
913 |
f = open(file_name, "r") |
914 |
try:
|
915 |
for line in f: |
916 |
# Ignore whitespace changes while comparing lines
|
917 |
if _SplitSshKey(line) != key_fields:
|
918 |
out.write(line) |
919 |
|
920 |
out.flush() |
921 |
os.rename(tmpname, file_name) |
922 |
finally:
|
923 |
f.close() |
924 |
finally:
|
925 |
out.close() |
926 |
except:
|
927 |
RemoveFile(tmpname) |
928 |
raise
|
929 |
|
930 |
|
931 |
def DaemonPidFileName(name): |
932 |
"""Compute a ganeti pid file absolute path
|
933 |
|
934 |
@type name: str
|
935 |
@param name: the daemon name
|
936 |
@rtype: str
|
937 |
@return: the full path to the pidfile corresponding to the given
|
938 |
daemon name
|
939 |
|
940 |
"""
|
941 |
return PathJoin(pathutils.RUN_DIR, "%s.pid" % name) |
942 |
|
943 |
|
944 |
def WritePidFile(pidfile): |
945 |
"""Write the current process pidfile.
|
946 |
|
947 |
@type pidfile: string
|
948 |
@param pidfile: the path to the file to be written
|
949 |
@raise errors.LockError: if the pid file already exists and
|
950 |
points to a live process
|
951 |
@rtype: int
|
952 |
@return: the file descriptor of the lock file; do not close this unless
|
953 |
you want to unlock the pid file
|
954 |
|
955 |
"""
|
956 |
# We don't rename nor truncate the file to not drop locks under
|
957 |
# existing processes
|
958 |
fd_pidfile = os.open(pidfile, os.O_RDWR | os.O_CREAT, 0600)
|
959 |
|
960 |
# Lock the PID file (and fail if not possible to do so). Any code
|
961 |
# wanting to send a signal to the daemon should try to lock the PID
|
962 |
# file before reading it. If acquiring the lock succeeds, the daemon is
|
963 |
# no longer running and the signal should not be sent.
|
964 |
try:
|
965 |
filelock.LockFile(fd_pidfile) |
966 |
except errors.LockError:
|
967 |
msg = ["PID file '%s' is already locked by another process" % pidfile]
|
968 |
# Try to read PID file
|
969 |
pid = _ParsePidFileContents(os.read(fd_pidfile, 100))
|
970 |
if pid > 0: |
971 |
msg.append(", PID read from file is %s" % pid)
|
972 |
raise errors.PidFileLockError("".join(msg)) |
973 |
|
974 |
os.write(fd_pidfile, "%d\n" % os.getpid())
|
975 |
|
976 |
return fd_pidfile
|
977 |
|
978 |
|
979 |
def ReadWatcherPauseFile(filename, now=None, remove_after=3600): |
980 |
"""Reads the watcher pause file.
|
981 |
|
982 |
@type filename: string
|
983 |
@param filename: Path to watcher pause file
|
984 |
@type now: None, float or int
|
985 |
@param now: Current time as Unix timestamp
|
986 |
@type remove_after: int
|
987 |
@param remove_after: Remove watcher pause file after specified amount of
|
988 |
seconds past the pause end time
|
989 |
|
990 |
"""
|
991 |
if now is None: |
992 |
now = time.time() |
993 |
|
994 |
try:
|
995 |
value = ReadFile(filename) |
996 |
except IOError, err: |
997 |
if err.errno != errno.ENOENT:
|
998 |
raise
|
999 |
value = None
|
1000 |
|
1001 |
if value is not None: |
1002 |
try:
|
1003 |
value = int(value)
|
1004 |
except ValueError: |
1005 |
logging.warning(("Watcher pause file (%s) contains invalid value,"
|
1006 |
" removing it"), filename)
|
1007 |
RemoveFile(filename) |
1008 |
value = None
|
1009 |
|
1010 |
if value is not None: |
1011 |
# Remove file if it's outdated
|
1012 |
if now > (value + remove_after):
|
1013 |
RemoveFile(filename) |
1014 |
value = None
|
1015 |
|
1016 |
elif now > value:
|
1017 |
value = None
|
1018 |
|
1019 |
return value
|
1020 |
|
1021 |
|
1022 |
def NewUUID(): |
1023 |
"""Returns a random UUID.
|
1024 |
|
1025 |
@note: This is a Linux-specific method as it uses the /proc
|
1026 |
filesystem.
|
1027 |
@rtype: str
|
1028 |
|
1029 |
"""
|
1030 |
return ReadFile(constants.RANDOM_UUID_FILE, size=128).rstrip("\n") |
1031 |
|
1032 |
|
1033 |
class TemporaryFileManager(object): |
1034 |
"""Stores the list of files to be deleted and removes them on demand.
|
1035 |
|
1036 |
"""
|
1037 |
|
1038 |
def __init__(self): |
1039 |
self._files = []
|
1040 |
|
1041 |
def __del__(self): |
1042 |
self.Cleanup()
|
1043 |
|
1044 |
def Add(self, filename): |
1045 |
"""Add file to list of files to be deleted.
|
1046 |
|
1047 |
@type filename: string
|
1048 |
@param filename: path to filename to be added
|
1049 |
|
1050 |
"""
|
1051 |
self._files.append(filename)
|
1052 |
|
1053 |
def Remove(self, filename): |
1054 |
"""Remove file from list of files to be deleted.
|
1055 |
|
1056 |
@type filename: string
|
1057 |
@param filename: path to filename to be deleted
|
1058 |
|
1059 |
"""
|
1060 |
self._files.remove(filename)
|
1061 |
|
1062 |
def Cleanup(self): |
1063 |
"""Delete all files marked for deletion
|
1064 |
|
1065 |
"""
|
1066 |
while self._files: |
1067 |
RemoveFile(self._files.pop())
|
1068 |
|
1069 |
|
1070 |
def IsUserInGroup(uid, gid): |
1071 |
"""Returns True if the user belongs to the group.
|
1072 |
|
1073 |
@type uid: int
|
1074 |
@param uid: the user id
|
1075 |
@type gid: int
|
1076 |
@param gid: the group id
|
1077 |
@rtype: bool
|
1078 |
|
1079 |
"""
|
1080 |
user = pwd.getpwuid(uid) |
1081 |
group = grp.getgrgid(gid) |
1082 |
return user.pw_gid == gid or user.pw_name in group.gr_mem |
1083 |
|
1084 |
|
1085 |
def CanRead(username, filename): |
1086 |
"""Returns True if the user can access (read) the file.
|
1087 |
|
1088 |
@type username: string
|
1089 |
@param username: the name of the user
|
1090 |
@type filename: string
|
1091 |
@param filename: the name of the file
|
1092 |
@rtype: bool
|
1093 |
|
1094 |
"""
|
1095 |
filestats = os.stat(filename) |
1096 |
user = pwd.getpwnam(username) |
1097 |
uid = user.pw_uid |
1098 |
user_readable = filestats.st_mode & stat.S_IRUSR != 0
|
1099 |
group_readable = filestats.st_mode & stat.S_IRGRP != 0
|
1100 |
return ((filestats.st_uid == uid and user_readable) |
1101 |
or (filestats.st_uid != uid and |
1102 |
IsUserInGroup(uid, filestats.st_gid) and group_readable))
|