golang将os.ModePerm转换为字符串

Question

I would like to have as a string the permissions representation of a file. Here is what I want to do :

fileInfo, err := os.Lstat(path)
fileMode := fileInfo.Mode()
// fileMode.String() gives dturwxrwxrwx or -rwxrwxrwx
// which i do not want because the size is not always the same
unixPerms := fileMode & os.ModePerm

I get -rwxrwxrwx for both cases, which is close to what i am looking for.

However, the returned object is of type os.FileMode. How can I then convert it into a string?