Add Socket::pair

Author: sfackler

Cargo.toml

@@ -23,3 +23,4 @@ libc = "0.2.14"
 
 [features]
 reuseport = []
+pair = []

src/socket.rs

@@ -36,6 +36,19 @@ impl Socket {
         })
     }
 
+    /// Creates a pair of sockets which are connected to each other.
+    ///
+    /// This function corresponds to `socketpair(2)`.
+    ///
+    /// This function is only available on Unix when the `pair` feature is
+    /// enabled.
+    #[cfg(all(unix, feature = "pair"))]
+    pub fn pair(domain: Domain, type_: Type, protocol: Option<Protocol>) -> io::Result<(Socket, Socket)> {
+        let protocol = protocol.map(|p| p.0).unwrap_or(0);
+        let sockets = sys::Socket::pair(domain.0, type_.0, protocol)?;
+        Ok((Socket { inner: sockets.0 }, Socket { inner: sockets.1 }))
+    }
+
     /// Consumes this `Socket`, converting it to a `TcpStream`.
     pub fn into_tcp_stream(self) -> net::TcpStream {
         self.into()

src/sys/unix/mod.rs

@@ -94,6 +94,21 @@ impl Socket {
         }
     }
 
+    pub fn pair(family: c_int, ty: c_int, protocol: c_int) -> io::Result<(Socket, Socket)> {
+        unsafe {
+            let mut fds = [0, 0];
+            cvt(libc::socketpair(family, ty, protocol, fds.as_mut_ptr()))?;
+            let fds = (Socket::from_raw_fd(fds[0]), Socket::from_raw_fd(fds[1]));
+            set_cloexec(fds.0.as_raw_fd())?;
+            set_cloexec(fds.1.as_raw_fd())?;
+            #[cfg(target_os = "macos")] {
+                fds.0.setsockopt(libc::SOL_SOCKET, libc::SO_NOSIGPIPE, 1i32)?;
+                fds.1.setsockopt(libc::SOL_SOCKET, libc::SO_NOSIGPIPE, 1i32)?;
+            }
+            Ok(fds)
+        }
+    }
+
     pub fn bind(&self, addr: &SockAddr) -> io::Result<()> {
         unsafe {
             cvt(libc::bind(self.fd, addr.as_ptr(), addr.len() as _)).map(|_| ())