# ControlSocket Cross-platform, `Sendable` line-oriented wrapper around a Tor control socket file descriptor. ``` final class ControlSocket ``` ## Overview `ControlSocket` is the POSIX-level plumbing that sits under [`TorControlClient`](/documentation/Tor/TorControlClient). It provides the three operations the control protocol demands (control-spec.txt §2): write a CRLF-terminated command line, read back a CRLF-terminated reply line, and assemble multi-line (`250-`, `250+`, `650+`) replies into a single `[String]`. The underlying FD is either the pre-authenticated socket from `tor_main_configuration_setup_control_socket()` (embedded mode) or a freshly-opened TCP connection to a listening `ControlPort`. Platform plumbing is abstracted across Darwin (`Darwin`), Linux (`Glibc`, `Musl`), and Windows (`WinSDK`) via `#if canImport(…)` guards. Sockets are configured with `SO_RCVTIMEO` so blocking `recv` calls honour [`readTimeout`](/documentation/Tor/ControlSocket/readTimeout) without requiring a polling loop. > Note: Conformance is `Sendable` (compiler-verified, no `@unchecked`). > All mutable state lives inside a `Mutex` from the > `Synchronization` module (SE-0410); callers may share instances > across concurrency domains and call methods concurrently — each > operation acquires the mutex for its own critical section. > Important: The `deinit` calls `close(2)` (or `closesocket()` on > Windows) **only** when ``doc://Tor/documentation/Tor/ControlSocket/init(fileDescriptor:ownsDescriptor:)`` was > invoked with `ownsDescriptor: true`. Embedded control sockets from > `tor_api` are owned by Tor; swift-tor must not close them. ## Topics ### Creating [`init(fileDescriptor:ownsDescriptor:)`](/documentation/Tor/ControlSocket/init(fileDescriptor:ownsDescriptor:)) Wrap an already-open file descriptor. [`init(host:port:)`](/documentation/Tor/ControlSocket/init(host:port:)) Open a TCP connection to a control port and wrap it. [`init(endpoint:)`](/documentation/Tor/ControlSocket/init(endpoint:)) Open a TCP connection to a typed [`HostPort`](/documentation/Tor/HostPort) endpoint. ### I/O [`writeLine(_:)`](/documentation/Tor/ControlSocket/writeLine(_:)) Send a single protocol command line. [`writeData(_:)`](/documentation/Tor/ControlSocket/writeData(_:)) Send a raw byte payload, looping until every byte is written. [`readLine()`](/documentation/Tor/ControlSocket/readLine()) Read one CRLF-terminated line, buffering residual bytes for the next call. [`readReply()`](/documentation/Tor/ControlSocket/readReply()) Read a complete control-protocol reply as an ordered `[String]`. [`sendCommand(_:)`](/documentation/Tor/ControlSocket/sendCommand(_:)) Send a command and return the parsed reply. [`readLineAsync()`](/documentation/Tor/ControlSocket/readLineAsync()) `readLine()` hoisted off the cooperative thread pool. ### State [`readTimeout`](/documentation/Tor/ControlSocket/readTimeout) Read timeout in seconds, applied to every [`readLine()`](/documentation/Tor/ControlSocket/readLine()) call. [`isValid`](/documentation/Tor/ControlSocket/isValid) `true` if the wrapped FD is non-negative, i.e. structurally valid.