support.py 文件源码

def can_xattr():
    global _can_xattr
    if _can_xattr is not None:
        return _can_xattr
    if not hasattr(os, "setxattr"):
        can = False
    else:
        tmp_fp, tmp_name = tempfile.mkstemp()
        try:
            with open(TESTFN, "wb") as fp:
                try:
                    # TESTFN & tempfile may use different file systems with
                    # different capabilities
                    os.setxattr(tmp_fp, b"user.test", b"")
                    os.setxattr(fp.fileno(), b"user.test", b"")
                    # Kernels < 2.6.39 don't respect setxattr flags.
                    kernel_version = platform.release()
                    m = re.match("2.6.(\d{1,2})", kernel_version)
                    can = m is None or int(m.group(1)) >= 39
                except OSError:
                    can = False
        finally:
            unlink(TESTFN)
            unlink(tmp_name)
    _can_xattr = can
    return can