FD Queue

FD Queue is a Rust abstraction for passing file descriptors between processes.

fd-queue provides traits for enqueuing and dequeuing file descriptors and implementations of those traits for different types of Unix sockets. Specifically fd-queue provides a blocking implementation, a non-blocking implementation base on mio, and a non-blocking implementation based on tokio.

Usage

Add this to your Cargo.toml

[dependencies]
fd-queue = {version = "1.0.0", features = ["net-fd"]}

This enables the blocking implementation of the traits for enqueuing and dequeuing file descriptors. See below for the other features. You can then use the library as follows:

use std::{
    fs::File,
    io::prelude::*,
    os::unix::io::FromRawFd,
};
use fd_queue::{EnqueueFd, DequeueFd, UnixStream};

let (mut sock1, mut sock2) = UnixStream::pair()?;

// sender side
let file: File = ...
sock1.enqueue(&file).expect("Can't enquque the file descriptor.");
sock1.write(b"a")?;
sock1.flush()?;

//receiver side
let mut buf = [0u8; 1];
sock2.read(&mut buf)?;
let fd = sock2.dequeue().expect("Can't dequeue the file descriptor.");
let file2 = unsafe { File::from_raw_fd(fd) };

Features

Usage of the library with the default features will include only the basic trait definitions DequeueFd and EnqueueFd together with their supporting types. With the default features there will be no implementations of the basic traits. To include implementations of the traits enable the following features:

Feature	Implementation	Additional Traits
net-fd	blocking	Read, Write
mio-fd	non-blocking	Read, Write, Evented
tokio-fd	non-blocking	AsyncRead, AsyncWrite

Rust Version Requirements

The library will always support the Rust version that is two earlier than the current stable version. The current Minimum Supported Rust Version (MSRV) is 1.62.0. Any change to the MSRV will be treated as a minor change for Semantic Version purposes.

Semantic Version and Release

This library follows semantic versioning.

The first non-pre-release version of the library will be version 1.0.0. This does not signal that the library is production ready or that we will attempt to avoid breaking changes. It rather signals exactly what the Semantic Versioning Specification says it does: there won't be any backward incompatible changes until version 2.0.0 (see here).

For a signal of the maturity of the library see the next heading which will be updated as the library matures.

Maturity

This library is an initial, experimental implementation that has not had any use in production. You should expect breaking changes (with an appropriate change in semantic version) as the library matures.

License

FD Queue is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE-2.0 or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in FD Queue by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.