lfs_fuse.py 文件源码

def getxattr(self, path, xattr, position=0):
        """Called with a specific namespace.name xattr.  Can return either
           a bytes array OR an int."""
        if position:
            raise TmfsOSError(errno.ENOSYS)    # never saw this in 8 months

        rsp = self.librarian(self.lcp('get_shelf', path=path))
        shelf = TMShelf(rsp)

        # Does this also need changed to support path instead of name?
        # Piggy back for queries by kernel (globals & fault handling).
        if xattr.startswith('_obtain_'):
            # this will need some work
            data = self.shadow.getxattr(shelf, xattr)
            try:
                return bytes(data.encode())
            except AttributeError as e:     # probably the "encode()"
                self._ret_is_string = False
                return bytes(data)

        # "ls" starts with simple getattr but then comes here for
        # security.selinux, system.posix_acl_access, and posix_acl_default.
        # ls -l can also do the same thing on '/'.  Save the round trips.

        # if xattr.startswith('security.') or not shelf_name:  # path == '/'
        if xattr.startswith('security.'):  # path == '/' is legal now
            return bytes(0)

        try:
            rsp = self.librarian(
                self.lcp('get_xattr', path=path, xattr=xattr))
            value = rsp['value']
            assert value is not None    # 'No such attribute'
            if isinstance(value, int):
                return value
            elif isinstance(value, str):
                # http://stackoverflow.com/questions/606191/convert-bytes-to-a-python-string
                return bytes(value.encode('cp437'))
            else:
                bytes(value.encode())
        except Exception as e:
            raise TmfsOSError(errno.ENODATA)    # syn for ENOATTR