feat: experimental codex stdio-to-uds subcommand (#5350)

codex-rs/stdio-to-uds/src/lib.rs

@@ -0,0 +1,52 @@
+#![deny(clippy::print_stdout)]
+
+use std::io;
+use std::io::Write;
+use std::net::Shutdown;
+use std::path::Path;
+use std::thread;
+
+use anyhow::Context;
+use anyhow::anyhow;
+
+#[cfg(unix)]
+use std::os::unix::net::UnixStream;
+
+#[cfg(windows)]
+use uds_windows::UnixStream;
+
+/// Connects to the Unix Domain Socket at `socket_path` and relays data between
+/// standard input/output and the socket.
+pub fn run(socket_path: &Path) -> anyhow::Result<()> {
+    let mut stream = UnixStream::connect(socket_path)
+        .with_context(|| format!("failed to connect to socket at {}", socket_path.display()))?;
+
+    let mut reader = stream
+        .try_clone()
+        .context("failed to clone socket for reading")?;
+
+    let stdout_thread = thread::spawn(move || -> io::Result<()> {
+        let stdout = io::stdout();
+        let mut handle = stdout.lock();
+        io::copy(&mut reader, &mut handle)?;
+        handle.flush()?;
+        Ok(())
+    });
+
+    let stdin = io::stdin();
+    {
+        let mut handle = stdin.lock();
+        io::copy(&mut handle, &mut stream).context("failed to copy data from stdin to socket")?;
+    }
+
+    stream
+        .shutdown(Shutdown::Write)
+        .context("failed to shutdown socket writer")?;
+
+    let stdout_result = stdout_thread
+        .join()
+        .map_err(|_| anyhow!("thread panicked while copying socket data to stdout"))?;
+    stdout_result.context("failed to copy data from socket to stdout")?;
+
+    Ok(())
+}

codex-rs/stdio-to-uds/src/main.rs

@@ -0,0 +1,19 @@
+use std::env;
+use std::path::PathBuf;
+use std::process;
+
+fn main() -> anyhow::Result<()> {
+    let mut args = env::args_os().skip(1);
+    let Some(socket_path) = args.next() else {
+        eprintln!("Usage: codex-stdio-to-uds <socket-path>");
+        process::exit(1);
+    };
+
+    if args.next().is_some() {
+        eprintln!("Expected exactly one argument: <socket-path>");
+        process::exit(1);
+    }
+
+    let socket_path = PathBuf::from(socket_path);
+    codex_stdio_to_uds::run(&socket_path)
+}