      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
    257
    258
    259
    260
    261
    262
    263
    264
    265
    266
    267
    268
    269
    270
    271
    272
    273
    274
    275
    276
    277
    278
    279
    280
    281
    282
    283
    284
    285
    286
    287
    288
    289
    290
    291
    292
    293
    294
    295
    296
    297
    298
    299
    300
    301
    302
    303
    304
    305
    306
    307
    308
    309
    310
    311
    312
    313
    314
    315
    316
    317
    318
    319
    320
    321
    322
    323
    324
    325
    326
    327
    328
    329
    330
    331
    332
    333
    334
    335
    336
    337
    338
    339
    340
    341
    342
    343
    344
    345
    346
    347
    348
    349
    350
    351
    352
    353
    354
    355
    356
    357
    358
    359
    360
    361
    362
    363
    364
    365
    366
    367
    368
    369
    370
    371
    372
    373
    374
    375
    376
    377
    378
    379
    380
    381
    382
    383
    384
    385
    386
    387
    388
    389
    390
    391
    392
    393
    394
    395
    396
    397
    398
    399
    400
    401
    402
    403
    404
    405
    406
    407
    408
    409
    410
    411
    412
    413
    414
    415
    416
    417
    418
    419
    420
    421
    422
    423
    424
    425
    426
    427
    428
    429
    430
    431
    432
    433
    434
    435
    436
    437
    438
    439
    440
    441
    442
    443
    444
    445
    446
    447
    448
    449
    450
    451
    452
    453
    454
    455
    456
    457
    458
    459
    460
    461
    462
    463
    464
    465
    466
    467
    468
    469
    470
    471
    472
    473
    474
    475
    476
    477
    478
    479
    480
    481
    482
    483
    484
    485
    486
    487
    488
    489
    490
    491
    492
    493
    494
    495
    496
    497
    498
    499
    500
    501
    502
    503
    504
    505
    506
    507
    508
    509
    510
    511
    512
    513
    514
    515
    516
    517
    518
    519
    520
    521
    522
    523
    524
    525
    526
    527
    528
    529
    530
    531
    532
    533
    534
    535
    536
    537
    538
    539
    540
    541
    542
    543
    544
    545
    546
    547
    548
    549
    550
    551
    552
    553
    554
    555
    556
    557
    558
    559
    560
    561
    562
    563
    564
    565
    566
    567
    568
    569
    570
    571
    572
    573
    574
    575
    576
    577
    578
    579
    580
    581
    582
    583
    584
    585
    586
    587
    588
    589
    590
    591
    592
    593
    594
    595
    596
    597
    598
    599
    600
    601
    602
    603
    604
    605
    606
    607
    608
    609
    610
    611
    612
    613
    614
    615
    616
    617
    618
    619
    620
    621
    622
    623
    624
    625
    626
    627
    628
    629
    630
    631
    632
    633
    634
    635
    636
    637
    638
    639
    640
    641
    642
    643
    644
    645
    646
    647
    648
    649
    650
    651
    652
    653
    654
    655
    656
    657
    658
    659
    660
    661
    662
    663
    664
    665
    666
    667
    668
    669
    670
    671
    672
    673
    674
    675
    676
    677
    678
    679
    680
    681
    682
    683
    684
    685
    686
    687
    688
    689
    690
    691
    692
    693
    694
    695
    696
    697
    698
    699
    700
    701
    702
    703
    704
    705
    706
    707
    708
    709
    710
    711
    712
    713
    714
    715
    716
    717
    718
    719
    720
    721
    722
    723
    724
    725
    726
    727
    728
    729
    730
    731
    732
    733
    734

    use crate::future::poll_fn;
    use crate::io::{AsyncRead, AsyncWrite, Interest, PollEvented, ReadBuf, Ready};
    use crate::net::unix::split::{split, ReadHalf, WriteHalf};
    use crate::net::unix::split_owned::{split_owned, OwnedReadHalf, OwnedWriteHalf};
    use crate::net::unix::ucred::{self, UCred};
    use crate::net::unix::SocketAddr;

    use std::convert::TryFrom;
    use std::fmt;
    use std::io::{self, Read, Write};
    use std::net::Shutdown;
    use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
    use std::os::unix::net;
    use std::path::Path;
    use std::pin::Pin;
    use std::task::{Context, Poll};

    cfg_io_util! {
        use bytes::BufMut;
    }

    cfg_net_unix! {
        /// A structure representing a connected Unix socket.
        ///
        /// This socket can be connected directly with `UnixStream::connect` or accepted
        /// from a listener with `UnixListener::incoming`. Additionally, a pair of
        /// anonymous Unix sockets can be created with `UnixStream::pair`.
        ///
        /// To shut down the stream in the write direction, you can call the
        /// [`shutdown()`] method. This will cause the other peer to receive a read of
        /// length 0, indicating that no more data will be sent. This only closes
        /// the stream in one direction.
        ///
        /// [`shutdown()`]: fn@crate::io::AsyncWriteExt::shutdown
        pub struct UnixStream {
            io: PollEvented<mio::net::UnixStream>,
        }
    }

    impl UnixStream {
        /// Connects to the socket named by `path`.
        ///
        /// This function will create a new Unix socket and connect to the path
        /// specified, associating the returned stream with the default event loop's
        /// handle.
        pub async fn connect<P>(path: P) -> io::Result<UnixStream>
        where
            P: AsRef<Path>,
        {
            let stream = mio::net::UnixStream::connect(path)?;
            let stream = UnixStream::new(stream)?;

            poll_fn(|cx| stream.io.registration().poll_write_ready(cx)).await?;
            Ok(stream)
        }

        /// Wait for any of the requested ready states.
        ///
        /// This function is usually paired with `try_read()` or `try_write()`. It
        /// can be used to concurrently read / write to the same socket on a single
        /// task without splitting the socket.
        ///
        /// # Examples
        ///
        /// Concurrently read and write to the stream on the same task without
        /// splitting.
        ///
        /// ```no_run
        /// use tokio::io::Interest;
        /// use tokio::net::UnixStream;
        /// use std::error::Error;
        /// use std::io;
        ///
        /// #[tokio::main]
        /// async fn main() -> Result<(), Box<dyn Error>> {
        ///     let dir = tempfile::tempdir().unwrap();
        ///     let bind_path = dir.path().join("bind_path");
        ///     let stream = UnixStream::connect(bind_path).await?;
        ///
        ///     loop {
        ///         let ready = stream.ready(Interest::READABLE | Interest::WRITABLE).await?;
        ///
        ///         if ready.is_readable() {
        ///             let mut data = vec![0; 1024];
        ///             // Try to read data, this may still fail with `WouldBlock`
        ///             // if the readiness event is a false positive.
        ///             match stream.try_read(&mut data) {
        ///                 Ok(n) => {
        ///                     println!("read {} bytes", n);
        ///                 }
        ///                 Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
        ///                     continue;
        ///                 }
        ///                 Err(e) => {
        ///                     return Err(e.into());
        ///                 }
        ///             }
        ///
        ///         }
        ///
        ///         if ready.is_writable() {
        ///             // Try to write data, this may still fail with `WouldBlock`
        ///             // if the readiness event is a false positive.
        ///             match stream.try_write(b"hello world") {
        ///                 Ok(n) => {
        ///                     println!("write {} bytes", n);
        ///                 }
        ///                 Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
        ///                     continue;
        ///                 }
        ///                 Err(e) => {
        ///                     return Err(e.into());
        ///                 }
        ///             }
        ///         }
        ///     }
        /// }
        /// ```
        pub async fn ready(&self, interest: Interest) -> io::Result<Ready> {
            let event = self.io.registration().readiness(interest).await?;
            Ok(event.ready)
        }

        /// Wait for the socket to become readable.
        ///
        /// This function is equivalent to `ready(Interest::READABLE)` and is usually
        /// paired with `try_read()`.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// use tokio::net::UnixStream;
        /// use std::error::Error;
        /// use std::io;
        ///
        /// #[tokio::main]
        /// async fn main() -> Result<(), Box<dyn Error>> {
        ///     // Connect to a peer
        ///     let dir = tempfile::tempdir().unwrap();
        ///     let bind_path = dir.path().join("bind_path");
        ///     let stream = UnixStream::connect(bind_path).await?;
        ///
        ///     let mut msg = vec![0; 1024];
        ///
        ///     loop {
        ///         // Wait for the socket to be readable
        ///         stream.readable().await?;
        ///
        ///         // Try to read data, this may still fail with `WouldBlock`
        ///         // if the readiness event is a false positive.
        ///         match stream.try_read(&mut msg) {
        ///             Ok(n) => {
        ///                 msg.truncate(n);
        ///                 break;
        ///             }
        ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
        ///                 continue;
        ///             }
        ///             Err(e) => {
        ///                 return Err(e.into());
        ///             }
        ///         }
        ///     }
        ///
        ///     println!("GOT = {:?}", msg);
        ///     Ok(())
        /// }
        /// ```
        pub async fn readable(&self) -> io::Result<()> {
            self.ready(Interest::READABLE).await?;
            Ok(())
        }

        /// Polls for read readiness.
        ///
        /// If the unix stream is not currently ready for reading, this method will
        /// store a clone of the `Waker` from the provided `Context`. When the unix
        /// stream becomes ready for reading, `Waker::wake` will be called on the
        /// waker.
        ///
        /// Note that on multiple calls to `poll_read_ready` or `poll_read`, only
        /// the `Waker` from the `Context` passed to the most recent call is
        /// scheduled to receive a wakeup. (However, `poll_write_ready` retains a
        /// second, independent waker.)
        ///
        /// This function is intended for cases where creating and pinning a future
        /// via [`readable`] is not feasible. Where possible, using [`readable`] is
        /// preferred, as this supports polling from multiple tasks at once.
        ///
        /// # Return value
        ///
        /// The function returns:
        ///
        /// * `Poll::Pending` if the unix stream is not ready for reading.
        /// * `Poll::Ready(Ok(()))` if the unix stream is ready for reading.
        /// * `Poll::Ready(Err(e))` if an error is encountered.
        ///
        /// # Errors
        ///
        /// This function may encounter any standard I/O error except `WouldBlock`.
        ///
        /// [`readable`]: method@Self::readable
        pub fn poll_read_ready(&self, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
            self.io.registration().poll_read_ready(cx).map_ok(|_| ())
        }

        /// Try to read data from the stream into the provided buffer, returning how
        /// many bytes were read.
        ///
        /// Receives any pending data from the socket but does not wait for new data
        /// to arrive. On success, returns the number of bytes read. Because
        /// `try_read()` is non-blocking, the buffer does not have to be stored by
        /// the async task and can exist entirely on the stack.
        ///
        /// Usually, [`readable()`] or [`ready()`] is used with this function.
        ///
        /// [`readable()`]: UnixStream::readable()
        /// [`ready()`]: UnixStream::ready()
        ///
        /// # Return
        ///
        /// If data is successfully read, `Ok(n)` is returned, where `n` is the
        /// number of bytes read. `Ok(0)` indicates the stream's read half is closed
        /// and will no longer yield data. If the stream is not ready to read data
        /// `Err(io::ErrorKind::WouldBlock)` is returned.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// use tokio::net::UnixStream;
        /// use std::error::Error;
        /// use std::io;
        ///
        /// #[tokio::main]
        /// async fn main() -> Result<(), Box<dyn Error>> {
        ///     // Connect to a peer
        ///     let dir = tempfile::tempdir().unwrap();
        ///     let bind_path = dir.path().join("bind_path");
        ///     let stream = UnixStream::connect(bind_path).await?;
        ///
        ///     loop {
        ///         // Wait for the socket to be readable
        ///         stream.readable().await?;
        ///
        ///         // Creating the buffer **after** the `await` prevents it from
        ///         // being stored in the async task.
        ///         let mut buf = [0; 4096];
        ///
        ///         // Try to read data, this may still fail with `WouldBlock`
        ///         // if the readiness event is a false positive.
        ///         match stream.try_read(&mut buf) {
        ///             Ok(0) => break,
        ///             Ok(n) => {
        ///                 println!("read {} bytes", n);
        ///             }
        ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
        ///                 continue;
        ///             }
        ///             Err(e) => {
        ///                 return Err(e.into());
        ///             }
        ///         }
        ///     }
        ///
        ///     Ok(())
        /// }
        /// ```
        pub fn try_read(&self, buf: &mut [u8]) -> io::Result<usize> {
            self.io
                .registration()
                .try_io(Interest::READABLE, || (&*self.io).read(buf))
        }

        cfg_io_util! {
            /// Try to read data from the stream into the provided buffer, advancing the
            /// buffer's internal cursor, returning how many bytes were read.
            ///
            /// Receives any pending data from the socket but does not wait for new data
            /// to arrive. On success, returns the number of bytes read. Because
            /// `try_read_buf()` is non-blocking, the buffer does not have to be stored by
            /// the async task and can exist entirely on the stack.
            ///
            /// Usually, [`readable()`] or [`ready()`] is used with this function.
            ///
            /// [`readable()`]: UnixStream::readable()
            /// [`ready()`]: UnixStream::ready()
            ///
            /// # Return
            ///
            /// If data is successfully read, `Ok(n)` is returned, where `n` is the
            /// number of bytes read. `Ok(0)` indicates the stream's read half is closed
            /// and will no longer yield data. If the stream is not ready to read data
            /// `Err(io::ErrorKind::WouldBlock)` is returned.
            ///
            /// # Examples
            ///
            /// ```no_run
            /// use tokio::net::UnixStream;
            /// use std::error::Error;
            /// use std::io;
            ///
            /// #[tokio::main]
            /// async fn main() -> Result<(), Box<dyn Error>> {
            ///     // Connect to a peer
            ///     let dir = tempfile::tempdir().unwrap();
            ///     let bind_path = dir.path().join("bind_path");
            ///     let stream = UnixStream::connect(bind_path).await?;
            ///
            ///     loop {
            ///         // Wait for the socket to be readable
            ///         stream.readable().await?;
            ///
            ///         let mut buf = Vec::with_capacity(4096);
            ///
            ///         // Try to read data, this may still fail with `WouldBlock`
            ///         // if the readiness event is a false positive.
            ///         match stream.try_read_buf(&mut buf) {
            ///             Ok(0) => break,
            ///             Ok(n) => {
            ///                 println!("read {} bytes", n);
            ///             }
            ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
            ///                 continue;
            ///             }
            ///             Err(e) => {
            ///                 return Err(e.into());
            ///             }
            ///         }
            ///     }
            ///
            ///     Ok(())
            /// }
            /// ```
            pub fn try_read_buf<B: BufMut>(&self, buf: &mut B) -> io::Result<usize> {
                self.io.registration().try_io(Interest::READABLE, || {
                    use std::io::Read;

                    let dst = buf.chunk_mut();
                    let dst =
                        unsafe { &mut *(dst as *mut _ as *mut [std::mem::MaybeUninit<u8>] as *mut [u8]) };

                    // Safety: We trust `UnixStream::read` to have filled up `n` bytes in the
                    // buffer.
                    let n = (&*self.io).read(dst)?;

                    unsafe {
                        buf.advance_mut(n);
                    }

                    Ok(n)
                })
            }
        }

        /// Wait for the socket to become writable.
        ///
        /// This function is equivalent to `ready(Interest::WRITABLE)` and is usually
        /// paired with `try_write()`.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// use tokio::net::UnixStream;
        /// use std::error::Error;
        /// use std::io;
        ///
        /// #[tokio::main]
        /// async fn main() -> Result<(), Box<dyn Error>> {
        ///     // Connect to a peer
        ///     let dir = tempfile::tempdir().unwrap();
        ///     let bind_path = dir.path().join("bind_path");
        ///     let stream = UnixStream::connect(bind_path).await?;
        ///
        ///     loop {
        ///         // Wait for the socket to be writable
        ///         stream.writable().await?;
        ///
        ///         // Try to write data, this may still fail with `WouldBlock`
        ///         // if the readiness event is a false positive.
        ///         match stream.try_write(b"hello world") {
        ///             Ok(n) => {
        ///                 break;
        ///             }
        ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
        ///                 continue;
        ///             }
        ///             Err(e) => {
        ///                 return Err(e.into());
        ///             }
        ///         }
        ///     }
        ///
        ///     Ok(())
        /// }
        /// ```
        pub async fn writable(&self) -> io::Result<()> {
            self.ready(Interest::WRITABLE).await?;
            Ok(())
        }

        /// Polls for write readiness.
        ///
        /// If the unix stream is not currently ready for writing, this method will
        /// store a clone of the `Waker` from the provided `Context`. When the unix
        /// stream becomes ready for writing, `Waker::wake` will be called on the
        /// waker.
        ///
        /// Note that on multiple calls to `poll_write_ready` or `poll_write`, only
        /// the `Waker` from the `Context` passed to the most recent call is
        /// scheduled to receive a wakeup. (However, `poll_read_ready` retains a
        /// second, independent waker.)
        ///
        /// This function is intended for cases where creating and pinning a future
        /// via [`writable`] is not feasible. Where possible, using [`writable`] is
        /// preferred, as this supports polling from multiple tasks at once.
        ///
        /// # Return value
        ///
        /// The function returns:
        ///
        /// * `Poll::Pending` if the unix stream is not ready for writing.
        /// * `Poll::Ready(Ok(()))` if the unix stream is ready for writing.
        /// * `Poll::Ready(Err(e))` if an error is encountered.
        ///
        /// # Errors
        ///
        /// This function may encounter any standard I/O error except `WouldBlock`.
        ///
        /// [`writable`]: method@Self::writable
        pub fn poll_write_ready(&self, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
            self.io.registration().poll_write_ready(cx).map_ok(|_| ())
        }

        /// Try to write a buffer to the stream, returning how many bytes were
        /// written.
        ///
        /// The function will attempt to write the entire contents of `buf`, but
        /// only part of the buffer may be written.
        ///
        /// This function is usually paired with `writable()`.
        ///
        /// # Return
        ///
        /// If data is successfully written, `Ok(n)` is returned, where `n` is the
        /// number of bytes written. If the stream is not ready to write data,
        /// `Err(io::ErrorKind::WouldBlock)` is returned.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// use tokio::net::UnixStream;
        /// use std::error::Error;
        /// use std::io;
        ///
        /// #[tokio::main]
        /// async fn main() -> Result<(), Box<dyn Error>> {
        ///     // Connect to a peer
        ///     let dir = tempfile::tempdir().unwrap();
        ///     let bind_path = dir.path().join("bind_path");
        ///     let stream = UnixStream::connect(bind_path).await?;
        ///
        ///     loop {
        ///         // Wait for the socket to be writable
        ///         stream.writable().await?;
        ///
        ///         // Try to write data, this may still fail with `WouldBlock`
        ///         // if the readiness event is a false positive.
        ///         match stream.try_write(b"hello world") {
        ///             Ok(n) => {
        ///                 break;
        ///             }
        ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
        ///                 continue;
        ///             }
        ///             Err(e) => {
        ///                 return Err(e.into());
        ///             }
        ///         }
        ///     }
        ///
        ///     Ok(())
        /// }
        /// ```
        pub fn try_write(&self, buf: &[u8]) -> io::Result<usize> {
            self.io
                .registration()
                .try_io(Interest::WRITABLE, || (&*self.io).write(buf))
        }

        /// Creates new `UnixStream` from a `std::os::unix::net::UnixStream`.
        ///
        /// This function is intended to be used to wrap a UnixStream from the
        /// standard library in the Tokio equivalent. The conversion assumes
        /// nothing about the underlying stream; it is left up to the user to set
        /// it in non-blocking mode.
        ///
        /// # Panics
        ///
        /// This function panics if thread-local runtime is not set.
        ///
        /// 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.
        pub fn from_std(stream: net::UnixStream) -> io::Result<UnixStream> {
            let stream = mio::net::UnixStream::from_std(stream);
            let io = PollEvented::new(stream)?;

            Ok(UnixStream { io })
        }

        /// Turn a [`tokio::net::UnixStream`] into a [`std::os::unix::net::UnixStream`].
        ///
        /// The returned [`std::os::unix::net::UnixStream`] will have nonblocking
        /// mode set as `true`.  Use [`set_nonblocking`] to change the blocking
        /// mode if needed.
        ///
        /// # Examples
        ///
        /// ```
        /// use std::error::Error;
        /// use std::io::Read;
        /// use tokio::net::UnixListener;
        /// # use tokio::net::UnixStream;
        /// # use tokio::io::AsyncWriteExt;
        ///
        /// #[tokio::main]
        /// async fn main() -> Result<(), Box<dyn Error>> {
        ///     let dir = tempfile::tempdir().unwrap();
        ///     let bind_path = dir.path().join("bind_path");
        ///
        ///     let mut data = [0u8; 12];
        ///     let listener = UnixListener::bind(&bind_path)?;
        /// #   let handle = tokio::spawn(async {
        /// #       let mut stream = UnixStream::connect(bind_path).await.unwrap();
        /// #       stream.write(b"Hello world!").await.unwrap();
        /// #   });
        ///     let (tokio_unix_stream, _) = listener.accept().await?;
        ///     let mut std_unix_stream = tokio_unix_stream.into_std()?;
        /// #   handle.await.expect("The task being joined has panicked");
        ///     std_unix_stream.set_nonblocking(false)?;
        ///     std_unix_stream.read_exact(&mut data)?;
        /// #   assert_eq!(b"Hello world!", &data);
        ///     Ok(())
        /// }
        /// ```
        /// [`tokio::net::UnixStream`]: UnixStream
        /// [`std::os::unix::net::UnixStream`]: std::os::unix::net::UnixStream
        /// [`set_nonblocking`]: fn@std::os::unix::net::UnixStream::set_nonblocking
        pub fn into_std(self) -> io::Result<std::os::unix::net::UnixStream> {
            self.io
                .into_inner()
                .map(|io| io.into_raw_fd())
                .map(|raw_fd| unsafe { std::os::unix::net::UnixStream::from_raw_fd(raw_fd) })
        }

        /// Creates an unnamed pair of connected sockets.
        ///
        /// This function will create a pair of interconnected Unix sockets for
        /// communicating back and forth between one another. Each socket will
        /// be associated with the default event loop's handle.
        pub fn pair() -> io::Result<(UnixStream, UnixStream)> {
            let (a, b) = mio::net::UnixStream::pair()?;
            let a = UnixStream::new(a)?;
            let b = UnixStream::new(b)?;

            Ok((a, b))
        }

        pub(crate) fn new(stream: mio::net::UnixStream) -> io::Result<UnixStream> {
            let io = PollEvented::new(stream)?;
            Ok(UnixStream { io })
        }

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

        /// Returns the socket address of the remote half of this connection.
        pub fn peer_addr(&self) -> io::Result<SocketAddr> {
            self.io.peer_addr().map(SocketAddr)
        }

        /// Returns effective credentials of the process which called `connect` or `pair`.
        pub fn peer_cred(&self) -> io::Result<UCred> {
            ucred::get_peer_cred(self)
        }

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

        /// Shuts 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(super) fn shutdown_std(&self, how: Shutdown) -> io::Result<()> {
            self.io.shutdown(how)
        }

        // These lifetime markers also appear in the generated documentation, and make
        // it more clear that this is a *borrowed* split.
        #[allow(clippy::needless_lifetimes)]
        /// Split a `UnixStream` into a read half and a write half, which can be used
        /// to read and write the stream concurrently.
        ///
        /// This method is more efficient than [`into_split`], but the halves cannot be
        /// moved into independently spawned tasks.
        ///
        /// [`into_split`]: Self::into_split()
        pub fn split<'a>(&'a mut self) -> (ReadHalf<'a>, WriteHalf<'a>) {
            split(self)
        }

        /// Splits a `UnixStream` into a read half and a write half, which can be used
        /// to read and write the stream concurrently.
        ///
        /// Unlike [`split`], the owned halves can be moved to separate tasks, however
        /// this comes at the cost of a heap allocation.
        ///
        /// **Note:** Dropping the write half will shut down the write half of the
        /// stream. This is equivalent to calling [`shutdown()`] on the `UnixStream`.
        ///
        /// [`split`]: Self::split()
        /// [`shutdown()`]: fn@crate::io::AsyncWriteExt::shutdown
        pub fn into_split(self) -> (OwnedReadHalf, OwnedWriteHalf) {
            split_owned(self)
        }
    }

    impl TryFrom<net::UnixStream> for UnixStream {
        type Error = io::Error;

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

    impl AsyncRead for UnixStream {
        fn poll_read(
            self: Pin<&mut Self>,
            cx: &mut Context<'_>,
            buf: &mut ReadBuf<'_>,
        ) -> Poll<io::Result<()>> {
            self.poll_read_priv(cx, buf)
        }
    }

    impl AsyncWrite for UnixStream {
        fn poll_write(
            self: Pin<&mut Self>,
            cx: &mut Context<'_>,
            buf: &[u8],
        ) -> Poll<io::Result<usize>> {
            self.poll_write_priv(cx, buf)
        }

        fn poll_write_vectored(
            self: Pin<&mut Self>,
            cx: &mut Context<'_>,
            bufs: &[io::IoSlice<'_>],
        ) -> Poll<io::Result<usize>> {
            self.poll_write_vectored_priv(cx, bufs)
        }

        fn is_write_vectored(&self) -> bool {
            true
        }

        fn poll_flush(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> {
            Poll::Ready(Ok(()))
        }

        fn poll_shutdown(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> {
            self.shutdown_std(std::net::Shutdown::Write)?;
            Poll::Ready(Ok(()))
        }
    }

    impl UnixStream {
        // == Poll IO functions that takes `&self` ==
        //
        // They are not public because (taken from the doc of `PollEvented`):
        //
        // While `PollEvented` is `Sync` (if the underlying I/O type is `Sync`), the
        // caller must ensure that there are at most two tasks that use a
        // `PollEvented` instance concurrently. One for reading and one for writing.
        // While violating this requirement is "safe" from a Rust memory model point
        // of view, it will result in unexpected behavior in the form of lost
        // notifications and tasks hanging.

        pub(crate) fn poll_read_priv(
            &self,
            cx: &mut Context<'_>,
            buf: &mut ReadBuf<'_>,
        ) -> Poll<io::Result<()>> {
            // Safety: `UnixStream::read` correctly handles reads into uninitialized memory
            unsafe { self.io.poll_read(cx, buf) }
        }

        pub(crate) fn poll_write_priv(
            &self,
            cx: &mut Context<'_>,
            buf: &[u8],
        ) -> Poll<io::Result<usize>> {
            self.io.poll_write(cx, buf)
        }

        pub(super) fn poll_write_vectored_priv(
            &self,
            cx: &mut Context<'_>,
            bufs: &[io::IoSlice<'_>],
        ) -> Poll<io::Result<usize>> {
            self.io.poll_write_vectored(cx, bufs)
        }
    }

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

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