97d4b42583
## Summary - add a codex-uds crate with async UnixListener and UnixStream wrappers - expose helpers for private socket directory setup and stale socket path checks - migrate codex-stdio-to-uds onto codex-uds and Tokio-based stdio/socket relaying - update the CLI stdio-to-uds command path for the async runner ## Tests - cargo test -p codex-uds -p codex-stdio-to-uds - cargo test -p codex-cli - just fmt - just fix -p codex-uds - just fix -p codex-stdio-to-uds - just fix -p codex-cli - just bazel-lock-check - git diff --check
codex-stdio-to-uds
Traditionally, there are two transport mechanisms for an MCP server: stdio and HTTP.
This crate helps enable a third, which is UNIX domain socket, because it has the advantages that:
- The UDS can be attached to long-running process, like an HTTP server.
- The UDS can leverage UNIX file permissions to restrict access.
To that end, this crate provides an adapter between a UDS and stdio. The idea is that someone could start an MCP server that communicates over /tmp/mcp.sock. Then the user could specify this on the fly like so:
codex --config mcp_servers.example={command="codex-stdio-to-uds",args=["/tmp/mcp.sock"]}
Unfortunately, the Rust standard library does not provide support for UNIX domain sockets on Windows today even though support was added in October 2018 in Windows 10:
https://github.com/rust-lang/rust/issues/56533
As a workaround, this crate uses codex-uds, which provides a cross-platform async UDS API backed by https://crates.io/crates/uds_windows on Windows.