net: add CloseRead, CloseWrite methods to UnixConn.

Fixes #3345.

R=golang-dev, r, rsc, dave
CC=golang-dev, remy
https://golang.org/cl/6214061

src/pkg/net/net_test.go

@@ -6,6 +6,8 @@ package net
 
 import (
 	"io"
+	"io/ioutil"
+	"os"
 	"runtime"
 	"testing"
 	"time"
@@ -58,6 +60,59 @@ func TestShutdown(t *testing.T) {
 	}
 }
 
+func TestShutdownUnix(t *testing.T) {
+	if runtime.GOOS == "plan9" {
+		t.Logf("skipping test on %q", runtime.GOOS)
+		return
+	}
+	f, err := ioutil.TempFile("", "go_net_unixtest")
+	if err != nil {
+		t.Fatalf("TempFile: %s", err)
+	}
+	f.Close()
+	tmpname := f.Name()
+	os.Remove(tmpname)
+	ln, err := Listen("unix", tmpname)
+	if err != nil {
+		t.Fatalf("ListenUnix on %s: %s", tmpname, err)
+	}
+	defer os.Remove(tmpname)
+
+	go func() {
+		c, err := ln.Accept()
+		if err != nil {
+			t.Fatalf("Accept: %v", err)
+		}
+		var buf [10]byte
+		n, err := c.Read(buf[:])
+		if n != 0 || err != io.EOF {
+			t.Fatalf("server Read = %d, %v; want 0, io.EOF", n, err)
+		}
+		c.Write([]byte("response"))
+		c.Close()
+	}()
+
+	c, err := Dial("unix", tmpname)
+	if err != nil {
+		t.Fatalf("Dial: %v", err)
+	}
+	defer c.Close()
+
+	err = c.(*UnixConn).CloseWrite()
+	if err != nil {
+		t.Fatalf("CloseWrite: %v", err)
+	}
+	var buf [10]byte
+	n, err := c.Read(buf[:])
+	if err != nil {
+		t.Fatalf("client Read: %d, %v", n, err)
+	}
+	got := string(buf[:n])
+	if got != "response" {
+		t.Errorf("read = %q, want \"response\"", got)
+	}
+}
+
 func TestTCPListenClose(t *testing.T) {
 	ln, err := Listen("tcp", "127.0.0.1:0")
 	if err != nil {

src/pkg/net/unixsock_plan9.go

@@ -72,6 +72,18 @@ func (c *UnixConn) WriteTo(b []byte, addr Addr) (n int, err error) {
 	return
 }
 
+// CloseRead shuts down the reading side of the Unix domain connection.
+// Most callers should just use Close.
+func (c *UnixConn) CloseRead() error {
+	return syscall.EPLAN9
+}
+
+// CloseWrite shuts down the writing side of the Unix domain connection.
+// Most callers should just use Close.
+func (c *UnixConn) CloseWrite() error {
+	return syscall.EPLAN9
+}
+
 // DialUnix connects to the remote address raddr on the network net,
 // which must be "unix" or "unixgram".  If laddr is not nil, it is used
 // as the local address for the connection.

src/pkg/net/unixsock_posix.go

@@ -207,6 +207,24 @@ func (c *UnixConn) WriteMsgUnix(b, oob []byte, addr *UnixAddr) (n, oobn int, err
 	return c.fd.WriteMsg(b, oob, nil)
 }
 
+// CloseRead shuts down the reading side of the Unix domain connection.
+// Most callers should just use Close.
+func (c *UnixConn) CloseRead() error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return c.fd.CloseRead()
+}
+
+// CloseWrite shuts down the writing side of the Unix domain connection.
+// Most callers should just use Close.
+func (c *UnixConn) CloseWrite() error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return c.fd.CloseWrite()
+}
+
 // DialUnix connects to the remote address raddr on the network net,
 // which must be "unix" or "unixgram".  If laddr is not nil, it is used
 // as the local address for the connection.