Struct UnixStream

pub struct UnixStream { /* private fields */ }

A structure representing a connected Unix socket with support for passing RawFd.

This is the primary implementation of EnqueueFd and DequeueFd and it is based on a blocking, Unix domain socket. Conceptually the key interfaces on UnixStream interact as shown in the following diagram:

EnqueueFd => Write => Read => DequeueFd

That is, you first enqueue a RawFd to the UnixStream and then Write at least one byte. On the other side of the UnixStream you then Read at least one byte and then dequeue the RawFd.

Examples

use std::fs::File;

let (mut sock1, mut sock2) = UnixStream::pair()?;

// sender side
// let file1: File = ...
sock1.enqueue(&file1).expect("Can't endqueue the file descriptor.");
sock1.write(b"a")?;
sock1.flush()?;

// receiver side
let mut buf = [0u8; 1];
sock2.read(&mut buf)?;
let fd = sock2.dequeue().expect("Can't dequeue the file descriptor.");
let file2 = unsafe { File::from_raw_fd(fd) };

Implementations

impl UnixStream

pub const FD_QUEUE_SIZE: usize = 2usize

The size of the bounded queue of outbound RawFd.

pub fn connect<P: AsRef<Path>>(path: P) -> Result<UnixStream>

Connects to the socket named by path.

Examples

use fd_queue::UnixStream;

// let path = ...

let sock = match UnixStream::connect(path) {
    Ok(sock) => sock,
    Err(e) => {
        println!("Couldn't connect to a socket: {}", e);
        return Ok(());
    }
};

pub fn pair() -> Result<(UnixStream, UnixStream)>

Creates an unnamed pair of connected sockets.

Returns two UnixStreams which are connected to each other.

Examples

use fd_queue::UnixStream;

let (sock1, sock2) = match UnixStream::pair() {
    Ok((sock1, sock2)) => (sock1, sock2),
    Err(e) => {
        println!("Couldn't create a pair of sockets: {}", e);
        return;
    }
};

pub fn try_clone(&self) -> Result<UnixStream>

Creates a new independently owned handle to the underlying socket.

The returned UnixStream is a reference to the same stream that this object references. Both handles will read and write the same stream of data, and options set on one stream will be propagated to the other stream.

Examples

use fd_queue::UnixStream;

let (sock1, _) = UnixStream::pair()?;

let sock2 = match sock1.try_clone() {
    Ok(sock) => sock,
    Err(e) => {
        println!("Couldn't clone a socket: {}", e);
        return Ok(());
    }
};

pub fn local_addr(&self) -> Result<SocketAddr>

Returns the socket address of the local half of this connection.

Examples

use fd_queue::UnixStream;

// let path = ...
let sock = UnixStream::connect(path)?;

let addr = match sock.local_addr() {
    Ok(addr) => addr,
    Err(e) => {
        println!("Couldn't get the local address: {}", e);
        return Ok(());
    }
};

pub fn peer_addr(&self) -> Result<SocketAddr>

Returns the socket address of the remote half of this connection.

Examples

use fd_queue::UnixStream;

// let path = ...
let sock = UnixStream::connect(path)?;

let addr = match sock.peer_addr() {
    Ok(addr) => addr,
    Err(e) => {
        println!("Couldn't get the local address: {}", e);
        return Ok(());
    }
};

pub fn take_error(&self) -> Result<Option<Error>>

Returns the value of the SO_ERROR option.

Examples

use fd_queue::UnixStream;

let (sock, _) = UnixStream::pair()?;

let err = match sock.take_error() {
    Ok(Some(err)) => err,
    Ok(None) => {
        println!("No error found.");
        return Ok(());
    }
    Err(e) => {
        println!("Couldn't take the SO_ERROR option: {}", e);
        return Ok(());
    }
};

pub fn shutdown(&self, how: Shutdown) -> Result<()>

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.

Examples

use fd_queue::UnixStream;
use std::net::Shutdown;
use std::io::Read;

let (mut sock, _) = UnixStream::pair()?;

sock.shutdown(Shutdown::Read).expect("Couldn't shutdown.");

let mut buf = [0u8; 256];
match sock.read(buf.as_mut()) {
    Ok(0) => {},
    _ => panic!("Read unexpectly not shut down."),
}

Trait Implementations

impl AsRawFd for UnixStream

fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor.

impl Debug for UnixStream

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl DequeueFd for UnixStream

Dequeue a RawFd that was previously transmitted across the UnixStream.

The RawFd that are dequeued were transmitted by a previous call to a method of Read.

fn dequeue(&mut self) -> Option<RawFd>

Dequeue a previously transmitted RawFd.

impl EnqueueFd for UnixStream

Enqueue a RawFd for later transmission across the UnixStream.

The RawFd will be transmitted on a later call to a method of Write. The number of RawFd that can be enqueued before being transmitted is bounded by FD_QUEUE_SIZE.

fn enqueue(&mut self, fd: &impl AsRawFd) -> Result<(), QueueFullError>

Enqueue fd for later transmission to a different process.

impl From<UnixStream> for UnixStream

fn from(inner: StdUnixStream) -> Self

Converts to this type from the input type.

impl FromRawFd for UnixStream

unsafe fn from_raw_fd(fd: RawFd) -> Self

Constructs a new instance of Self from the given raw file descriptor.

impl IntoRawFd for UnixStream

fn into_raw_fd(self) -> RawFd

Consumes this object, returning the raw underlying file descriptor.

impl Read for UnixStream

Receive bytes and RawFd that are transmitted across the UnixStream.

The RawFd that are received along with the bytes will be available through the method of the DequeueFd implementation. The number of RawFd that can be received in a single call to one of the Read methods is bounded by FD_QUEUE_SIZE. It is an error if the other side of this UnixStream attempted to send more control messages (including RawFd) than will fit in the buffer that has been sized for receiving up to FD_QUEUE_SIZE RawFd.

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

impl Write for UnixStream

Transmit bytes and RawFd across the UnixStream.

The RawFd that are transmitted along with the bytes are ones that were previously enqueued for transmission through the method of EnqueueFd.

fn write(&mut self, buf: &[u8]) -> Result<usize>

Writes a buffer into this writer, returning how many bytes were written.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>

Like write, except that it writes from a slice of buffers.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.