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
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
use std::net::Shutdown;
use std::os::fd::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
use std::os::unix::net::{self, SocketAddr};
use std::path::Path;
use std::{fmt, io};

use crate::io_source::IoSource;
use crate::{event, sys, Interest, Registry, Token};

/// A Unix datagram socket.
pub struct UnixDatagram {
    inner: IoSource<net::UnixDatagram>,
}

impl UnixDatagram {
    /// Creates a Unix datagram socket bound to the given path.
    pub fn bind<P: AsRef<Path>>(path: P) -> io::Result<UnixDatagram> {
        let addr = SocketAddr::from_pathname(path)?;
        UnixDatagram::bind_addr(&addr)
    }

    /// Creates a new `UnixDatagram` bound to the specified socket `address`.
    pub fn bind_addr(address: &SocketAddr) -> io::Result<UnixDatagram> {
        sys::uds::datagram::bind_addr(address).map(UnixDatagram::from_std)
    }

    /// Creates a new `UnixDatagram` from a standard `net::UnixDatagram`.
    ///
    /// This function is intended to be used to wrap a Unix datagram from the
    /// standard library in the Mio equivalent. The conversion assumes nothing
    /// about the underlying datagram; it is left up to the user to set it in
    /// non-blocking mode.
    pub fn from_std(socket: net::UnixDatagram) -> UnixDatagram {
        UnixDatagram {
            inner: IoSource::new(socket),
        }
    }

    /// Connects the socket to the specified address.
    ///
    /// This may return a `WouldBlock` in which case the socket connection
    /// cannot be completed immediately.
    pub fn connect<P: AsRef<Path>>(&self, path: P) -> io::Result<()> {
        self.inner.connect(path)
    }

    /// Creates a Unix Datagram socket which is not bound to any address.
    pub fn unbound() -> io::Result<UnixDatagram> {
        sys::uds::datagram::unbound().map(UnixDatagram::from_std)
    }

    /// Create an unnamed pair of connected sockets.
    pub fn pair() -> io::Result<(UnixDatagram, UnixDatagram)> {
        sys::uds::datagram::pair().map(|(socket1, socket2)| {
            (
                UnixDatagram::from_std(socket1),
                UnixDatagram::from_std(socket2),
            )
        })
    }

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

    /// Returns the address of this socket's peer.
    ///
    /// The `connect` method will connect the socket to a peer.
    pub fn peer_addr(&self) -> io::Result<SocketAddr> {
        self.inner.peer_addr()
    }

    /// Receives data from the socket.
    ///
    /// On success, returns the number of bytes read and the address from
    /// whence the data came.
    pub fn recv_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {
        self.inner.do_io(|inner| inner.recv_from(buf))
    }

    /// Receives data from the socket.
    ///
    /// On success, returns the number of bytes read.
    pub fn recv(&self, buf: &mut [u8]) -> io::Result<usize> {
        self.inner.do_io(|inner| inner.recv(buf))
    }

    /// Sends data on the socket to the specified address.
    ///
    /// On success, returns the number of bytes written.
    pub fn send_to<P: AsRef<Path>>(&self, buf: &[u8], path: P) -> io::Result<usize> {
        self.inner.do_io(|inner| inner.send_to(buf, path))
    }

    /// Sends data on the socket to the socket's peer.
    ///
    /// The peer address may be set by the `connect` method, and this method
    /// will return an error if the socket has not already been connected.
    ///
    /// On success, returns the number of bytes written.
    pub fn send(&self, buf: &[u8]) -> io::Result<usize> {
        self.inner.do_io(|inner| inner.send(buf))
    }

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

    /// Shut down the read, write, or both halves of this connection.
    ///
    /// This function will cause all pending and future I/O calls on the
    /// specified portions to immediately return with an appropriate value
    /// (see the documentation of `Shutdown`).
    pub fn shutdown(&self, how: Shutdown) -> io::Result<()> {
        self.inner.shutdown(how)
    }

    /// Execute an I/O operation ensuring that the socket receives more events
    /// if it hits a [`WouldBlock`] error.
    ///
    /// # Notes
    ///
    /// This method is required to be called for **all** I/O operations to
    /// ensure the user will receive events once the socket is ready again after
    /// returning a [`WouldBlock`] error.
    ///
    /// [`WouldBlock`]: io::ErrorKind::WouldBlock
    ///
    /// # Examples
    ///
    /// ```
    /// # use std::error::Error;
    /// #
    /// # fn main() -> Result<(), Box<dyn Error>> {
    /// use std::io;
    /// use std::os::fd::AsRawFd;
    /// use mio::net::UnixDatagram;
    ///
    /// let (dgram1, dgram2) = UnixDatagram::pair()?;
    ///
    /// // Wait until the dgram is writable...
    ///
    /// // Write to the dgram using a direct libc call, of course the
    /// // `io::Write` implementation would be easier to use.
    /// let buf = b"hello";
    /// let n = dgram1.try_io(|| {
    ///     let buf_ptr = &buf as *const _ as *const _;
    ///     let res = unsafe { libc::send(dgram1.as_raw_fd(), buf_ptr, buf.len(), 0) };
    ///     if res != -1 {
    ///         Ok(res as usize)
    ///     } else {
    ///         // If EAGAIN or EWOULDBLOCK is set by libc::send, the closure
    ///         // should return `WouldBlock` error.
    ///         Err(io::Error::last_os_error())
    ///     }
    /// })?;
    /// eprintln!("write {} bytes", n);
    ///
    /// // Wait until the dgram is readable...
    ///
    /// // Read from the dgram using a direct libc call, of course the
    /// // `io::Read` implementation would be easier to use.
    /// let mut buf = [0; 512];
    /// let n = dgram2.try_io(|| {
    ///     let buf_ptr = &mut buf as *mut _ as *mut _;
    ///     let res = unsafe { libc::recv(dgram2.as_raw_fd(), buf_ptr, buf.len(), 0) };
    ///     if res != -1 {
    ///         Ok(res as usize)
    ///     } else {
    ///         // If EAGAIN or EWOULDBLOCK is set by libc::recv, the closure
    ///         // should return `WouldBlock` error.
    ///         Err(io::Error::last_os_error())
    ///     }
    /// })?;
    /// eprintln!("read {} bytes", n);
    /// # Ok(())
    /// # }
    /// ```
    pub fn try_io<F, T>(&self, f: F) -> io::Result<T>
    where
        F: FnOnce() -> io::Result<T>,
    {
        self.inner.do_io(|_| f())
    }
}

impl event::Source for UnixDatagram {
    fn register(
        &mut self,
        registry: &Registry,
        token: Token,
        interests: Interest,
    ) -> io::Result<()> {
        self.inner.register(registry, token, interests)
    }

    fn reregister(
        &mut self,
        registry: &Registry,
        token: Token,
        interests: Interest,
    ) -> io::Result<()> {
        self.inner.reregister(registry, token, interests)
    }

    fn deregister(&mut self, registry: &Registry) -> io::Result<()> {
        self.inner.deregister(registry)
    }
}

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

impl IntoRawFd for UnixDatagram {
    fn into_raw_fd(self) -> RawFd {
        self.inner.into_inner().into_raw_fd()
    }
}

impl AsRawFd for UnixDatagram {
    fn as_raw_fd(&self) -> RawFd {
        self.inner.as_raw_fd()
    }
}

impl FromRawFd for UnixDatagram {
    /// Converts a `RawFd` to a `UnixDatagram`.
    ///
    /// # Notes
    ///
    /// The caller is responsible for ensuring that the socket is in
    /// non-blocking mode.
    unsafe fn from_raw_fd(fd: RawFd) -> UnixDatagram {
        UnixDatagram::from_std(FromRawFd::from_raw_fd(fd))
    }
}

impl From<UnixDatagram> for net::UnixDatagram {
    fn from(datagram: UnixDatagram) -> Self {
        // Safety: This is safe since we are extracting the raw fd from a well-constructed
        // mio::net::uds::UnixListener which ensures that we actually pass in a valid file
        // descriptor/socket
        unsafe { net::UnixDatagram::from_raw_fd(datagram.into_raw_fd()) }
    }
}

impl AsFd for UnixDatagram {
    fn as_fd(&self) -> BorrowedFd<'_> {
        self.inner.as_fd()
    }
}