ipc.rs

src/common/ipc.rs is the single thing the server and commander processes must agree on at runtime: where their Unix socket lives and what flows over it. It lives in common (rather than in either role’s module) because both depend on it, and it carries no crypto or network code, so the commander can link it without OpenSSL. It is gated behind any(with-server, with-commander).

The 24-byte wire format

#![allow(unused)]
fn main() {
pub(crate) const CMDR_DATA_SIZE: usize = 24;

pub(crate) struct CommanderData {
    pub(crate) cmd_hash: u64,
    pub(crate) ip: IpAddr,
}
}

The From conversions are infallible (the buffer is a fixed 24 bytes): one direction writes cmd_hash.to_be_bytes() then serialize_ip(&ip), the other reads them back and runs normalize_ip on the IP, so an IPv4 client IP arrives at the commander as a plain IpAddr::V4. The server produces a CommanderData (in handler.rs) and connects to the socket; the commander consumes it and binds the socket.

The socket path

#![allow(unused)]
fn main() {
pub fn get_commander_unix_socket_path(config_dir: &Path) -> PathBuf {
    resolve_path(config_dir).join("ruroco.socket")
}
}

Both the server (when deciding where to connect) and the commander (when deciding where to bind) call this with their socket directory, so they always agree: <resolved socket dir>/ruroco.socket. resolve_path is applied first so a relative dir resolves consistently on both sides. That socket directory is config_dir by default, or the optional socket_dir field when set (e.g. a systemd RuntimeDirectory like /run/ruroco); both sides read the same field, so they stay in agreement.

One config file, two views

The socket directory (config_dir, or socket_dir when set) is the one configuration value that must match between the two processes (otherwise they resolve different socket paths and the IPC silently breaks). It is therefore kept in a single shared config.toml file read by both. But the two processes do not share a config struct: each deserializes the same file through its own view, declaring only the fields it uses and ignoring the rest.

• server::config::ConfigServer reads the server-only fields (ips, rate limit, clock skew) plus config_dir. See Config and keys.
• commander::config::ConfigCommander reads config_dir (plus the optional socket_dir) and the commander-only socket_user / socket_group. See Commander.

The command set is a separate file again (commands.toml, ConfigCommands), read only by the commander, so the network-facing server never loads it.