1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
use crate::io::{Interest, PollEvented};
use crate::net::unix::{SocketAddr, UnixStream};

use std::fmt;
use std::io;
#[cfg(not(tokio_no_as_fd))]
use std::os::unix::io::{AsFd, BorrowedFd};
use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
use std::os::unix::net;
use std::path::Path;
use std::task::{Context, Poll};

cfg_net_unix! {
    /// A Unix socket which can accept connections from other Unix sockets.
    ///
    /// You can accept a new connection by using the [`accept`](`UnixListener::accept`) method.
    ///
    /// A `UnixListener` can be turned into a `Stream` with [`UnixListenerStream`].
    ///
    /// [`UnixListenerStream`]: https://docs.rs/tokio-stream/0.1/tokio_stream/wrappers/struct.UnixListenerStream.html
    ///
    /// # Errors
    ///
    /// Note that accepting a connection can lead to various errors and not all
    /// of them are necessarily fatal ‒ for example having too many open file
    /// descriptors or the other side closing the connection while it waits in
    /// an accept queue. These would terminate the stream if not handled in any
    /// way.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::net::UnixListener;
    ///
    /// #[tokio::main]
    /// async fn main() {
    ///     let listener = UnixListener::bind("/path/to/the/socket").unwrap();
    ///     loop {
    ///         match listener.accept().await {
    ///             Ok((stream, _addr)) => {
    ///                 println!("new client!");
    ///             }
    ///             Err(e) => { /* connection failed */ }
    ///         }
    ///     }
    /// }
    /// ```
    pub struct UnixListener {
        io: PollEvented<mio::net::UnixListener>,
    }
}

impl UnixListener {
    /// Creates a new `UnixListener` bound to the specified path.
    ///
    /// # Panics
    ///
    /// This function panics if it is not called from within a runtime with
    /// IO enabled.
    ///
    /// The runtime is usually set implicitly when this function is called
    /// from a future driven by a tokio runtime, otherwise runtime can be set
    /// explicitly with [`Runtime::enter`](crate::runtime::Runtime::enter) function.
    #[track_caller]
    pub fn bind<P>(path: P) -> io::Result<UnixListener>
    where
        P: AsRef<Path>,
    {
        let listener = mio::net::UnixListener::bind(path)?;
        let io = PollEvented::new(listener)?;
        Ok(UnixListener { io })
    }

    /// Creates new `UnixListener` from a `std::os::unix::net::UnixListener `.
    ///
    /// This function is intended to be used to wrap a UnixListener from the
    /// standard library in the Tokio equivalent.
    ///
    /// # Notes
    ///
    /// The caller is responsible for ensuring that the listener is in
    /// non-blocking mode. Otherwise all I/O operations on the listener
    /// will block the thread, which will cause unexpected behavior.
    /// Non-blocking mode can be set using [`set_nonblocking`].
    ///
    /// [`set_nonblocking`]: std::os::unix::net::UnixListener::set_nonblocking
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use tokio::net::UnixListener;
    /// use std::os::unix::net::UnixListener as StdUnixListener;
    /// # use std::error::Error;
    ///
    /// # async fn dox() -> Result<(), Box<dyn Error>> {
    /// let std_listener = StdUnixListener::bind("/path/to/the/socket")?;
    /// std_listener.set_nonblocking(true)?;
    /// let listener = UnixListener::from_std(std_listener)?;
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// # Panics
    ///
    /// This function panics if it is not called from within a runtime with
    /// IO enabled.
    ///
    /// The runtime is usually set implicitly when this function is called
    /// from a future driven by a tokio runtime, otherwise runtime can be set
    /// explicitly with [`Runtime::enter`](crate::runtime::Runtime::enter) function.
    #[track_caller]
    pub fn from_std(listener: net::UnixListener) -> io::Result<UnixListener> {
        let listener = mio::net::UnixListener::from_std(listener);
        let io = PollEvented::new(listener)?;
        Ok(UnixListener { io })
    }

    /// Turns a [`tokio::net::UnixListener`] into a [`std::os::unix::net::UnixListener`].
    ///
    /// The returned [`std::os::unix::net::UnixListener`] will have nonblocking mode
    /// set as `true`. Use [`set_nonblocking`] to change the blocking mode if needed.
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// # use std::error::Error;
    /// # async fn dox() -> Result<(), Box<dyn Error>> {
    /// let tokio_listener = tokio::net::UnixListener::bind("/path/to/the/socket")?;
    /// let std_listener = tokio_listener.into_std()?;
    /// std_listener.set_nonblocking(false)?;
    /// # Ok(())
    /// # }
    /// ```
    ///
    /// [`tokio::net::UnixListener`]: UnixListener
    /// [`std::os::unix::net::UnixListener`]: std::os::unix::net::UnixListener
    /// [`set_nonblocking`]: fn@std::os::unix::net::UnixListener::set_nonblocking
    pub fn into_std(self) -> io::Result<std::os::unix::net::UnixListener> {
        self.io
            .into_inner()
            .map(|io| io.into_raw_fd())
            .map(|raw_fd| unsafe { net::UnixListener::from_raw_fd(raw_fd) })
    }

    /// Returns the local socket address of this listener.
    pub fn local_addr(&self) -> io::Result<SocketAddr> {
        self.io.local_addr().map(SocketAddr)
    }

    /// Returns the value of the `SO_ERROR` option.
    pub fn take_error(&self) -> io::Result<Option<io::Error>> {
        self.io.take_error()
    }

    /// Accepts a new incoming connection to this listener.
    ///
    /// # Cancel safety
    ///
    /// This method is cancel safe. If the method is used as the event in a
    /// [`tokio::select!`](crate::select) statement and some other branch
    /// completes first, then it is guaranteed that no new connections were
    /// accepted by this method.
    pub async fn accept(&self) -> io::Result<(UnixStream, SocketAddr)> {
        let (mio, addr) = self
            .io
            .registration()
            .async_io(Interest::READABLE, || self.io.accept())
            .await?;

        let addr = SocketAddr(addr);
        let stream = UnixStream::new(mio)?;
        Ok((stream, addr))
    }

    /// Polls to accept a new incoming connection to this listener.
    ///
    /// If there is no connection to accept, `Poll::Pending` is returned and the
    /// current task will be notified by a waker.  Note that on multiple calls
    /// to `poll_accept`, only the `Waker` from the `Context` passed to the most
    /// recent call is scheduled to receive a wakeup.
    pub fn poll_accept(&self, cx: &mut Context<'_>) -> Poll<io::Result<(UnixStream, SocketAddr)>> {
        let (sock, addr) = ready!(self.io.registration().poll_read_io(cx, || self.io.accept()))?;
        let addr = SocketAddr(addr);
        let sock = UnixStream::new(sock)?;
        Poll::Ready(Ok((sock, addr)))
    }
}

impl TryFrom<std::os::unix::net::UnixListener> for UnixListener {
    type Error = io::Error;

    /// Consumes stream, returning the tokio I/O object.
    ///
    /// This is equivalent to
    /// [`UnixListener::from_std(stream)`](UnixListener::from_std).
    fn try_from(stream: std::os::unix::net::UnixListener) -> io::Result<Self> {
        Self::from_std(stream)
    }
}

impl fmt::Debug for UnixListener {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.io.fmt(f)
    }
}

impl AsRawFd for UnixListener {
    fn as_raw_fd(&self) -> RawFd {
        self.io.as_raw_fd()
    }
}

#[cfg(not(tokio_no_as_fd))]
impl AsFd for UnixListener {
    fn as_fd(&self) -> BorrowedFd<'_> {
        unsafe { BorrowedFd::borrow_raw(self.as_raw_fd()) }
    }
}