1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
|
#
# Copyright (c) 2011-2014 Red Hat, Inc. <http://www.redhat.com>
# This file is part of GlusterFS.
# This file is licensed to you under your choice of the GNU Lesser
# General Public License, version 3 or any later version (LGPLv3 or
# later), or the GNU General Public License, version 2 (GPLv2), in all
# cases as published by the Free Software Foundation.
#
import os
import sys
from ctypes import CDLL, c_int, create_string_buffer
from ctypes.util import find_library
class Xattr(object):
"""singleton that wraps the extended attribues system
interface for python using ctypes
Just implement it to the degree we need it, in particular
- we need just the l*xattr variants, ie. we never want symlinks to be
followed
- don't need size discovery for getxattr, as we always know the exact
sizes we expect
"""
if sys.hexversion >= 0x02060000:
from ctypes import DEFAULT_MODE
libc = CDLL(find_library("libc"), DEFAULT_MODE, None, True)
else:
libc = CDLL(find_library("libc"))
@classmethod
def geterrno(cls):
if sys.hexversion >= 0x02060000:
from ctypes import get_errno
return get_errno()
# breaks on NetBSD
return c_int.in_dll(cls.libc, 'errno').value
@classmethod
def raise_oserr(cls):
errn = cls.geterrno()
raise OSError(errn, os.strerror(errn))
@classmethod
def _query_xattr(cls, path, siz, syscall, *a):
if siz:
buf = create_string_buffer('\0' * siz)
else:
buf = None
ret = getattr(cls.libc, syscall)(*((path,) + a + (buf, siz)))
if ret == -1:
cls.raise_oserr()
if siz:
return buf.raw[:ret]
else:
return ret
@classmethod
def lgetxattr(cls, path, attr, siz=0):
return cls._query_xattr(path, siz, 'lgetxattr', attr)
@classmethod
def lgetxattr_buf(cls, path, attr):
"""lgetxattr variant with size discovery"""
size = cls.lgetxattr(path, attr)
if size == -1:
cls.raise_oserr()
if size == 0:
return ''
return cls.lgetxattr(path, attr, size)
@classmethod
def llistxattr(cls, path, siz=0):
ret = cls._query_xattr(path, siz, 'llistxattr')
if isinstance(ret, str):
ret = ret.split('\0')
return ret
@classmethod
def lsetxattr(cls, path, attr, val):
ret = cls.libc.lsetxattr(path, attr, val, len(val), 0)
if ret == -1:
cls.raise_oserr()
@classmethod
def lremovexattr(cls, path, attr):
ret = cls.libc.lremovexattr(path, attr)
if ret == -1:
cls.raise_oserr()
@classmethod
def llistxattr_buf(cls, path):
"""listxattr variant with size discovery"""
size = cls.llistxattr(path)
if size == -1:
cls.raise_oserr()
if size == 0:
return []
return cls.llistxattr(path, size)
|
