我正在尝试使用由TcpStream（来自crates.io）包裹的openssl::ssl::SslStream制作与服务器通信的客户端程序。它应该等待read，并处理从服务器发送的数据没有延迟。同时，无论阅读如何，都应该能够向服务器发送消息。
我尝试了一些方法，比如
read和write方法都需要可变引用，因此我无法将单个流传递给两个线程。TcpStream似乎没有clone方法，SslStream也没有。TcpStream和as_raw_fd复制from_raw_fd：fn irc_read(mut stream: SslStream<TcpStream>) {
loop {
let mut buf = vec![0; 2048];
let resp = stream.ssl_read(&mut buf);
match resp {
// Process Message
}
}
}
fn irc_write(mut stream: SslStream<TcpStream>) {
thread::sleep(Duration::new(3, 0));
let msg = "QUIT\n";
let res = stream.ssl_write(msg.as_bytes());
let _ = stream.flush();
match res {
// Process
}
}
fn main() {
let ctx = SslContext::new(SslMethod::Sslv23).unwrap();
let read_ssl = Ssl::new(&ctx).unwrap();
let write_ssl = Ssl::new(&ctx).unwrap();
let raw_stream = TcpStream::connect((SERVER, PORT)).unwrap();
let mut fd_stream: TcpStream;
unsafe {
fd_stream = TcpStream::from_raw_fd(raw_stream.as_raw_fd());
}
let mut read_stream = SslStream::connect(read_ssl, raw_stream).unwrap();
let mut write_stream = SslStream::connect(write_ssl, fd_stream).unwrap();
let read_thread = thread::spawn(move || {
irc_read(read_stream);
});
let write_thread = thread::spawn(move || {
irc_write(write_stream);
});
let _ = read_thread.join();
let _ = write_thread.join();
}
此代码编译，但在第二个SslStream::connect
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Failure(Ssl(ErrorStack([Error { library: "SSL routines", function: "SSL23_GET_SERVER_HELLO", reason: "unknown protocol" }])))', ../src/libcore/result.rs:788
stack backtrace:
1: 0x556d719c6069 - std::sys::backtrace::tracing::imp::write::h00e948915d1e4c72
2: 0x556d719c9d3c - std::panicking::default_hook::_{{closure}}::h7b8a142818383fb8
3: 0x556d719c8f89 - std::panicking::default_hook::h41cf296f654245d7
4: 0x556d719c9678 - std::panicking::rust_panic_with_hook::h4cbd7ca63ce1aee9
5: 0x556d719c94d2 - std::panicking::begin_panic::h93672d0313d5e8e9
6: 0x556d719c9440 - std::panicking::begin_panic_fmt::hd0daa02942245d81
7: 0x556d719c93c1 - rust_begin_unwind
8: 0x556d719ffcbf - core::panicking::panic_fmt::hbfc935564d134c1b
9: 0x556d71899f02 - core::result::unwrap_failed::h66f79b2edc69ddfd
at /buildslave/rust-buildbot/slave/stable-dist-rustc-linux/build/obj/../src/libcore/result.rs:29
10: 0x556d718952cb - _<core..result..Result<T, E>>::unwrap::h49a140af593bc4fa
at /buildslave/rust-buildbot/slave/stable-dist-rustc-linux/build/obj/../src/libcore/result.rs:726
11: 0x556d718a5e3d - dbrust::main::h24a50e631826915e
at /home/lastone817/dbrust/src/main.rs:87
12: 0x556d719d1826 - __rust_maybe_catch_panic
13: 0x556d719c8702 - std::rt::lang_start::h53bf99b0829cc03c
14: 0x556d718a6b83 - main
15: 0x7f40a0b5082f - __libc_start_main
16: 0x556d7188d038 - _start
17: 0x0 - <unknown>
error: Process didn't exit successfully: `target/debug/dbrust` (exit code: 101)
到目前为止，我发现的最佳解决方案是使用非阻塞。我在流上使用Mutex并将其传递给两个线程。然后读取线程获取锁并调用read。如果没有消息则释放锁，以便写线程可以使用该流。使用此方法，读取线程忙于等待，导致100％的CPU消耗。我认为这不是最佳解决方案。
有没有一种安全的方法来分离流的读写方面？
答案 0 :(得分：-1)
我使用Rust的std::cell::UnsafeCell完成了将SSL流拆分为读取部分和写入部分的操作。
extern crate native_tls;
use native_tls::TlsConnector;
use std::cell::UnsafeCell;
use std::error::Error;
use std::io::Read;
use std::io::Write;
use std::marker::Sync;
use std::net::TcpStream;
use std::sync::Arc;
use std::sync::Mutex;
use std::thread;
struct UnsafeMutator<T> {
value: UnsafeCell<T>,
}
impl<T> UnsafeMutator<T> {
fn new(value: T) -> UnsafeMutator<T> {
return UnsafeMutator {
value: UnsafeCell::new(value),
};
}
fn mut_value(&self) -> &mut T {
return unsafe { &mut *self.value.get() };
}
}
unsafe impl<T> Sync for UnsafeMutator<T> {}
struct ReadWrapper<R>
where
R: Read,
{
inner: Arc<UnsafeMutator<R>>,
}
impl<R: Read> Read for ReadWrapper<R> {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, std::io::Error> {
return self.inner.mut_value().read(buf);
}
}
struct WriteWrapper<W>
where
W: Write,
{
inner: Arc<UnsafeMutator<W>>,
}
impl<W: Write> Write for WriteWrapper<W> {
fn write(&mut self, buf: &[u8]) -> Result<usize, std::io::Error> {
return self.inner.mut_value().write(buf);
}
fn flush(&mut self) -> Result<(), std::io::Error> {
return self.inner.mut_value().flush();
}
}
pub struct Socket {
pub output_stream: Arc<Mutex<Write + Send>>,
pub input_stream: Arc<Mutex<Read + Send>>,
}
impl Socket {
pub fn bind(host: &str, port: u16, secure: bool) -> Result<Socket, Box<Error>> {
let tcp_stream = match TcpStream::connect((host, port)) {
Ok(x) => x,
Err(e) => return Err(Box::new(e)),
};
if secure {
let tls_connector = TlsConnector::builder().build().unwrap();
let tls_stream = match tls_connector.connect(host, tcp_stream) {
Ok(x) => x,
Err(e) => return Err(Box::new(e)),
};
let mutator = Arc::new(UnsafeMutator::new(tls_stream));
let input_stream = Arc::new(Mutex::new(ReadWrapper {
inner: mutator.clone(),
}));
let output_stream = Arc::new(Mutex::new(WriteWrapper { inner: mutator }));
let socket = Socket {
output_stream,
input_stream,
};
return Ok(socket);
} else {
let mutator = Arc::new(UnsafeMutator::new(tcp_stream));
let input_stream = Arc::new(Mutex::new(ReadWrapper {
inner: mutator.clone(),
}));
let output_stream = Arc::new(Mutex::new(WriteWrapper { inner: mutator }));
let socket = Socket {
output_stream,
input_stream,
};
return Ok(socket);
}
}
}
fn main() {
let socket = Arc::new(Socket::bind("google.com", 443, true).unwrap());
let socket_clone = Arc::clone(&socket);
let reader_thread = thread::spawn(move || {
let mut res = vec![];
let mut input_stream = socket_clone.input_stream.lock().unwrap();
input_stream.read_to_end(&mut res).unwrap();
println!("{}", String::from_utf8_lossy(&res));
});
let writer_thread = thread::spawn(move || {
let mut output_stream = socket.output_stream.lock().unwrap();
output_stream.write_all(b"GET / HTTP/1.0\r\n\r\n").unwrap();
});
writer_thread.join().unwrap();
reader_thread.join().unwrap();
}