Add socketpair

3 files changed, 56 insertions, 0 deletions

diff --git a/src/sys/socket/ffi.rs b/src/sys/socket/ffi.rs
index 612854de..c445c8c9 100644
--- a/src/sys/socket/ffi.rs
+++ b/src/sys/socket/ffi.rs
@@ -8,4 +8,11 @@ extern {
         optname: c_int,
         optval: *mut c_void,
         optlen: *mut socklen_t) -> c_int;
+
+    pub fn socketpair(
+        domain:     c_int,
+        typ:        c_int,
+        protocol:   c_int,
+        sv:         *mut c_int
+    ) -> c_int;
 }
diff --git a/src/sys/socket/mod.rs b/src/sys/socket/mod.rs
index 72bc4ccf..33f02ee7 100644
--- a/src/sys/socket/mod.rs
+++ b/src/sys/socket/mod.rs
@@ -105,6 +105,40 @@ pub fn socket(domain: AddressFamily, ty: SockType, flags: SockFlag) -> Result<Fd
     Ok(res)
 }
 
+/// Create a pair of connected sockets
+///
+/// [Further reading](http://man7.org/linux/man-pages/man2/socketpair.2.html)
+pub fn socketpair(domain: AddressFamily, ty: SockType, protocol: c_int,
+                  flags: SockFlag) -> Result<(Fd, Fd)> {
+    let mut ty = ty as c_int;
+    let feat_atomic = features::socket_atomic_cloexec();
+
+    if feat_atomic {
+        ty = ty | flags.bits();
+    }
+    let mut fds = [-1, -1];
+    let res = unsafe {
+        ffi::socketpair(domain as c_int, ty, protocol, fds.as_mut_ptr())
+    };
+
+    if res < 0 {
+        return Err(Error::Sys(Errno::last()));
+    }
+
+    if !feat_atomic {
+        if flags.contains(SOCK_CLOEXEC) {
+            try!(fcntl(fds[0], F_SETFD(FD_CLOEXEC)));
+            try!(fcntl(fds[1], F_SETFD(FD_CLOEXEC)));
+        }
+
+        if flags.contains(SOCK_NONBLOCK) {
+            try!(fcntl(fds[0], F_SETFL(O_NONBLOCK)));
+            try!(fcntl(fds[1], F_SETFL(O_NONBLOCK)));
+        }
+    }
+    Ok((fds[0], fds[1]))
+}
+
 /// Listen for connections on a socket
 ///
 /// [Further reading](http://man7.org/linux/man-pages/man2/listen.2.html)
diff --git a/test/sys/test_socket.rs b/test/sys/test_socket.rs
index 1983e7b5..e8cb4bed 100644
--- a/test/sys/test_socket.rs
+++ b/test/sys/test_socket.rs
@@ -48,3 +48,18 @@ pub fn test_getsockname() {
 
     assert_eq!(addr, res.to_str());
 }
+
+#[test]
+pub fn test_socketpair() {
+    use nix::unistd::{read, write};
+    use nix::sys::socket::{socketpair, AddressFamily, SockType, SockFlag};
+
+    let (fd1, fd2) = socketpair(AddressFamily::Unix, SockType::Stream, 0,
+                                SockFlag::empty())
+                     .unwrap();
+    write(fd1, b"hello").unwrap();
+    let mut buf = [0;5];
+    read(fd2, &mut buf).unwrap();
+
+    assert_eq!(&buf[..], b"hello");
+}