pub fn runtime_dir() -> Result<PathBuf>Expand description
The runtime directory, created and owner-verified.
$ONLYNE_RUNTIME_DIR when set and non-empty, /tmp/onlyne-<uid>/
otherwise. Adoption follows [ensure_private_dir]: a directory this user
owns that is closed to group and other access, which this process can still
write. /tmp is shared and world-executable, so another user can create
/tmp/onlyne-<uid> first; an endpoint inside a directory that user owns is
one that user could swap from under a live daemon, which is the refusal
[ensure_private_dir] makes.