1 #![warn(rust_2018_idioms)]
2 // Wasi does not support panic recovery or threading
3 #![cfg(all(feature = "full", not(target_os = "wasi")))]
4
5 use tokio::net::TcpListener;
6 use tokio::runtime;
7 use tokio_test::{assert_ok, assert_pending};
8
9 use futures::task::{waker_ref, ArcWake};
10 use std::future::Future;
11 use std::net::TcpStream;
12 use std::pin::Pin;
13 use std::sync::{mpsc, Arc, Mutex};
14 use std::task::Context;
15
16 struct Task<T> {
17 future: Mutex<Pin<Box<T>>>,
18 }
19
20 impl<T: Send> ArcWake for Task<T> {
wake_by_ref(_: &Arc<Self>)21 fn wake_by_ref(_: &Arc<Self>) {
22 // Do nothing...
23 }
24 }
25
26 impl<T> Task<T> {
new(future: T) -> Task<T>27 fn new(future: T) -> Task<T> {
28 Task {
29 future: Mutex::new(Box::pin(future)),
30 }
31 }
32 }
33
34 #[test]
test_drop_on_notify()35 fn test_drop_on_notify() {
36 // When the reactor receives a kernel notification, it notifies the
37 // task that holds the associated socket. If this notification results in
38 // the task being dropped, the socket will also be dropped.
39 //
40 // Previously, there was a deadlock scenario where the reactor, while
41 // notifying, held a lock and the task being dropped attempted to acquire
42 // that same lock in order to clean up state.
43 //
44 // To simulate this case, we create a fake executor that does nothing when
45 // the task is notified. This simulates an executor in the process of
46 // shutting down. Then, when the task handle is dropped, the task itself is
47 // dropped.
48
49 let rt = runtime::Builder::new_current_thread()
50 .enable_all()
51 .build()
52 .unwrap();
53
54 let (addr_tx, addr_rx) = mpsc::channel();
55
56 // Define a task that just drains the listener
57 let task = Arc::new(Task::new(async move {
58 // Create a listener
59 let listener = assert_ok!(TcpListener::bind("127.0.0.1:0").await);
60
61 // Send the address
62 let addr = listener.local_addr().unwrap();
63 addr_tx.send(addr).unwrap();
64
65 loop {
66 let _ = listener.accept().await;
67 }
68 }));
69
70 {
71 let _enter = rt.enter();
72 let waker = waker_ref(&task);
73 let mut cx = Context::from_waker(&waker);
74 assert_pending!(task.future.lock().unwrap().as_mut().poll(&mut cx));
75 }
76
77 // Get the address
78 let addr = addr_rx.recv().unwrap();
79
80 drop(task);
81
82 // Establish a connection to the acceptor
83 let _s = TcpStream::connect(addr).unwrap();
84
85 // Force the reactor to turn
86 rt.block_on(async {});
87 }
88
89 #[test]
90 #[should_panic(
91 expected = "A Tokio 1.x context was found, but IO is disabled. Call `enable_io` on the runtime builder to enable IO."
92 )]
panics_when_io_disabled()93 fn panics_when_io_disabled() {
94 let rt = runtime::Builder::new_current_thread().build().unwrap();
95
96 rt.block_on(async {
97 let _ =
98 tokio::net::TcpListener::from_std(std::net::TcpListener::bind("127.0.0.1:0").unwrap());
99 });
100 }
101