Abstract recvtty to a single function

contrib/cmd/recvtty/recvtty.go

@@ -24,7 +24,6 @@ import (
 	"os"
 	"strings"
 
-	"github.com/containerd/console"
 	"github.com/opencontainers/runc/libcontainer/utils"
 	"github.com/urfave/cli"
 )
@@ -67,45 +66,11 @@ func bail(err error) {
 
 func handleSingle(path string) error {
 	// Open a socket.
-	ln, err := net.Listen("unix", path)
-	if err != nil {
-		return err
-	}
-	defer ln.Close()
-
-	// We only accept a single connection, since we can only really have
-	// one reader for os.Stdin. Plus this is all a PoC.
-	conn, err := ln.Accept()
-	if err != nil {
-		return err
-	}
-	defer conn.Close()
-
-	// Close ln, to allow for other instances to take over.
-	ln.Close()
-
-	// Get the fd of the connection.
-	unixconn, ok := conn.(*net.UnixConn)
-	if !ok {
-		return fmt.Errorf("failed to cast to unixconn")
-	}
-
-	socket, err := unixconn.File()
-	if err != nil {
-		return err
-	}
-	defer socket.Close()
-
-	// Get the master file descriptor from runC.
-	master, err := utils.RecvFd(socket)
-	if err != nil {
-		return err
-	}
-	c, err := console.ConsoleFromFile(master)
+	c, err := utils.ConsoleSocket(path)
 	if err != nil {
 		return err
 	}
-	console.ClearONLCR(c.Fd())
+	defer c.Close()
 
 	// Copy from our stdio to the master fd.
 	quitChan := make(chan struct{})

libcontainer/utils/utils.go

@@ -4,12 +4,15 @@ import (
 	"crypto/rand"
 	"encoding/hex"
 	"encoding/json"
+	"fmt"
 	"io"
+	"net"
 	"os"
 	"path/filepath"
 	"strings"
 	"unsafe"
 
+	"github.com/containerd/console"
 	"golang.org/x/sys/unix"
 )
 
@@ -125,3 +128,49 @@ func Annotations(labels []string) (bundle string, userAnnotations map[string]str
 func GetIntSize() int {
 	return int(unsafe.Sizeof(1))
 }
+
+// ConsoleSocket opens a socket on the given path and receives the console file descriptors from there
+func ConsoleSocket(path string) (console.Console, error) {
+	// Open a socket.
+	ln, err := net.Listen("unix", path)
+	if err != nil {
+		return nil, err
+	}
+	defer ln.Close()
+
+	// We only accept a single connection, since we can only really have
+	// one reader for os.Stdin
+	conn, err := ln.Accept()
+	if err != nil {
+		return nil, err
+	}
+	defer conn.Close()
+
+	// Close ln, to allow for other instances to take over.
+	ln.Close()
+
+	// Get the fd of the connection.
+	unixconn, ok := conn.(*net.UnixConn)
+	if !ok {
+		return nil, fmt.Errorf("failed to cast to unixconn")
+	}
+
+	socket, err := unixconn.File()
+	if err != nil {
+		return nil, err
+	}
+	defer socket.Close()
+
+	// Get the master file descriptor from runC.
+	master, err := RecvFd(socket)
+	if err != nil {
+		return nil, err
+	}
+	c, err := console.ConsoleFromFile(master)
+	if err != nil {
+		return nil, err
+	}
+	console.ClearONLCR(c.Fd())
+
+	return c, nil
+}