Function atomic_replace_labeled 

pub(crate) fn atomic_replace_labeled<F>(
    root: &Dir,
    destname: impl AsRef<Utf8Path>,
    mode: Mode,
    policy: Option<&SePolicy>,
    f: F,
) -> Result<()>
where
    F: FnOnce(&mut BufWriter<TempFile<'_>>) -> Result<()>,

A wrapper for atomically writing a file, also optionally setting a SELinux label. The label is looked up for destname as if root were /, so pass the directory that stands for the target’s root, never a subdirectory of it.