Module fsutil 

Restricted directory/file creation (0o700 dirs, 0o600 files on Unix).

Prefer atomic_write_0600 / ensure_dir_0700 over bare fs::write for anything that may hold secrets or session metadata.

Functions

atomic_write_0600

Atomically write bytes to path with mode 0o600 (create temp with mode, then rename).

ensure_dir_0700

Ensure dir exists with mode 0o700 on Unix.