open.mp Rust C API

Minimal Rust component example for the official open.mp C API.

This project is a proof of concept for running open.mp server logic from Rust without writing a Pawn gamemode. It builds a native 32-bit Linux component, loads the open.mp C API at runtime, registers a player event callback, and uses the component lifecycle hook exposed by the C API.

Status

Experimental. The component loads in open.mp v1.5.8.3079, but the Rust API is still raw FFI plus a small C shim. Treat it as a starting point for a safer wrapper, not as a finished framework.

What It Does

• Exports ComponentEntryPoint, so open.mp loads it as a native component.
• Initializes the official C API through components/$CAPI.so.
• Creates an OpenMPRustCapi component.
• Uses the C API onReady component lifecycle hook as the startup hook.
• Sets the gamemode text to open.mp Rust C API.
• Adds one spawn class.
• Registers onPlayerConnect.
• Sends a client message from Rust when a player connects.

Requirements

• Rust with the i686-unknown-linux-gnu target.
• Zig, when cross-compiling from macOS or another non-32-bit-Linux host.
• open.mp v1.5.8.3079 or newer.
• Docker, only for the included smoke test.

Install the Rust target:

rustup target add i686-unknown-linux-gnu

Build

From macOS with Zig installed:

cargo build --release --target i686-unknown-linux-gnu

The repo-local Cargo config routes the C shim and final link through:

zig cc -target x86-linux-gnu

The deployable component artifact is:

target/i686-unknown-linux-gnu/release/libopenmp_rust_capi.so

On a Debian or Ubuntu x86_64 build host, a native multilib toolchain also works:

sudo apt-get update
sudo apt-get install -y clang libclang-dev gcc-multilib libc6-dev-i386
cargo build --release --target i686-unknown-linux-gnu

Install In open.mp

Build the release artifact, then copy it into the server components/ directory:

cp target/i686-unknown-linux-gnu/release/libopenmp_rust_capi.so \
  /path/to/omp-server/components/OpenMPRustCapi.so

Or use the helper:

./scripts/install-to-server.sh /path/to/omp-server

Start the server from its root directory. The C API initializer loads ./components/$CAPI.so, so the working directory matters.

Expected startup log lines:

[openmp-rust-capi] component ready
[openmp-rust-capi] onReady startup hook fired
[openmp-rust-capi] registered onPlayerConnect handler

When a player connects, they should receive:

Hello <name>, this message came from Rust.

Smoke Test

With Docker and Zig installed, this downloads the pinned open.mp Linux x86 server, copies the component into components/, starts the server under linux/386, and checks the startup log:

./scripts/smoke-test-openmp.sh

The test is considered passing when open.mp logs:

Successfully loaded component OpenMPRustCapi
[openmp-rust-capi] component ready
[openmp-rust-capi] onReady startup hook fired
[openmp-rust-capi] registered onPlayerConnect handler

On Apple Silicon, Docker runs this through qemu. A qemu segfault can appear when timeout tears down the server; the same shutdown issue occurs without this Rust component.

Lifecycle Notes

The C API Component.Create path exposes onReady, onReset, and onFree callbacks. It does not directly expose Pawn's OnGameModeInit callback.

For this component path, onReady is the closest native startup hook: it fires after components are initialized and before normal server runtime.

Repository Layout

• src/lib.rs - Rust component entrypoint, lifecycle hooks, and event callback.
• c/omp_capi_shim.c - narrow C wrapper around the generated open.mp C API.
• c/omp_capi_shim.h - C shim declarations consumed by bindgen.
• vendor/openmp-capi/ - vendored open.mp C API header and license.
• build.rs - compiles the C shim and generates Rust FFI bindings.
• scripts/install-to-server.sh - builds and installs the component into a server.
• scripts/smoke-test-openmp.sh - end-to-end open.mp server smoke test.

Development Checks

cargo fmt --check
cargo check
cargo check --target i686-unknown-linux-gnu
./scripts/smoke-test-openmp.sh

License

This project is licensed under the MIT License. See LICENSE.

The vendored open.mp C API header is licensed under the Mozilla Public License 2.0. See vendor/openmp-capi/LICENSE.md and THIRD_PARTY_NOTICES.md.