我试图使用Unix套接字对使用子Ruby进程传递Rust进程。我只使用Ruby尝试过相同的功能,但它似乎无法使用Rust。
我已经尝试将“rust_socket”文件描述符传递给Ruby脚本,将“ruby_socket”文件描述符传递给Ruby以及读取/写入套接字的不同组合。我觉得我应该传递“ruby_socket”文件描述符,但是当我这样做时,我得到一个错误的文件描述符错误。
// The rust side of things
use std::process::Command;
use std::os::unix::net::UnixStream;
use std::os::unix::io::IntoRawFd;
use std::io::{Read, Write};
fn main() {
let (rust_socket, mut ruby_socket) = match UnixStream::pair() {
Ok((rust_socket, ruby_socket)) => (rust_socket, ruby_socket),
Err(e) => {
println!("Failed to open socket pair: {:?}", e);
return;
}
};
let _output = Command::new("ruby")
.args(&["/home/station/workspace/rust_server/src/client.rb", &rust_socket.into_raw_fd().to_string()])
.spawn()
.expect("Failed to start ruby process");
let mut response = String::new();
ruby_socket.read_to_string(&mut response).unwrap();
}
# The ruby side of things
require "socket"
begin
socket = UNIXSocket.for_fd(ARGV.shift.to_i)
socket.send("Hello world!\n", 0)
ensure
socket&.close
end
我希望能够读到“Hello world!”来自Rust的字符串,但它不起作用。
问题似乎是Rust sets all file descriptors to be closed when a child is created by setting the FD_CLOEXEC
flag。解决这个问题的唯一方法似乎是使用libc来调用fcntl
。
这里有一些似乎有效的代码,但我不知道Rust,所以使用风险自负。你将遇到的另一个问题是你需要在产生孩子后关闭rust_socket
的父方面,否则read_to_string
将永远阻止等待关闭流。您可以使用drop
执行此操作,但您还需要使用AsRawFd
而不是IntoRawFd
:
use std::process::Command;
use std::os::unix::net::UnixStream;
use std::os::unix::io::AsRawFd;
use std::io::Read;
extern crate libc;
fn main() {
// Create the socket pair.
let (rust_socket, mut ruby_socket) = UnixStream::pair().unwrap();
// Unset FD_CLOEXEC on the socket to be passed to the child.
let fd = rust_socket.as_raw_fd();
unsafe {
let flags = libc::fcntl(fd, libc::F_GETFD);
libc::fcntl(fd, libc::F_SETFD, flags & !libc::FD_CLOEXEC);
}
// Spawn the child
let _output = Command::new("ruby")
.args(&["client.rb", &fd.to_string()])
.spawn();
// After spawning, close the parents side of rust_socket.
// If we use IntoRawFd, rust_socket would have been moved by this point
// so we need AsRawFD instead.
drop(rust_socket);
let mut response = String::new();
ruby_socket.read_to_string(&mut response).unwrap();
println!("Ruby said '{}'", response);
}