diff options
Diffstat (limited to 'geo-replication/syncdaemon/libcxattr.py')
| -rw-r--r-- | geo-replication/syncdaemon/libcxattr.py | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/geo-replication/syncdaemon/libcxattr.py b/geo-replication/syncdaemon/libcxattr.py new file mode 100644 index 00000000000..e6406c36bd7 --- /dev/null +++ b/geo-replication/syncdaemon/libcxattr.py @@ -0,0 +1,112 @@ +# +# 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 +from ctypes import CDLL, get_errno +from py2py3 import (bytearray_to_str, gr_create_string_buffer, + gr_query_xattr, gr_lsetxattr, gr_lremovexattr) + + +class Xattr(object): + + """singleton that wraps the extended attributes 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 + """ + + libc = CDLL("libc.so.6", use_errno=True) + + @classmethod + def geterrno(cls): + return get_errno() + + @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 = gr_create_string_buffer(siz) + else: + buf = None + ret = getattr(cls.libc, syscall)(*((path,) + a + (buf, siz))) + if ret == -1: + cls.raise_oserr() + if siz: + # py2 and py3 compatibility. Convert bytes array + # to string + result = bytearray_to_str(buf.raw) + return result[:ret] + else: + return ret + + @classmethod + def lgetxattr(cls, path, attr, siz=0): + return gr_query_xattr(cls, 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 = gr_query_xattr(cls, path, siz, 'llistxattr') + if isinstance(ret, str): + ret = ret.strip('\0') + ret = ret.split('\0') if ret else [] + return ret + + @classmethod + def lsetxattr(cls, path, attr, val): + ret = gr_lsetxattr(cls, path, attr, val) + if ret == -1: + cls.raise_oserr() + + @classmethod + def lremovexattr(cls, path, attr): + ret = gr_lremovexattr(cls, path, attr) + if ret == -1: + cls.raise_oserr() + + @classmethod + def llistxattr_buf(cls, path): + """listxattr variant with size discovery""" + try: + # Assuming no more than 100 xattrs in a file/directory and + # each xattr key length will be less than 256 bytes + # llistxattr will be called with bigger size so that + # listxattr will not fail with ERANGE. OSError will be + # raised if fails even with the large size specified. + size = 256 * 100 + return cls.llistxattr(path, size) + except OSError: + # If fixed length failed for getting list of xattrs then + # use the llistxattr call to get the size and use that + # size to get the list of xattrs. + size = cls.llistxattr(path) + if size == -1: + cls.raise_oserr() + if size == 0: + return [] + + return cls.llistxattr(path, size) |
