Split term files to make it easier to manage

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

libcontainer/nsinit/std_term.go

@@ -0,0 +1,49 @@
+package nsinit
+
+import (
+	"io"
+	"os"
+	"os/exec"
+)
+
+type StdTerminal struct {
+	stdin          io.Reader
+	stdout, stderr io.Writer
+}
+
+func (s *StdTerminal) SetMaster(*os.File) {
+	// no need to set master on non tty
+}
+
+func (s *StdTerminal) Close() error {
+	return nil
+}
+
+func (s *StdTerminal) Resize(h, w int) error {
+	return nil
+}
+
+func (s *StdTerminal) Attach(command *exec.Cmd) error {
+	inPipe, err := command.StdinPipe()
+	if err != nil {
+		return err
+	}
+	outPipe, err := command.StdoutPipe()
+	if err != nil {
+		return err
+	}
+	errPipe, err := command.StderrPipe()
+	if err != nil {
+		return err
+	}
+
+	go func() {
+		defer inPipe.Close()
+		io.Copy(inPipe, s.stdin)
+	}()
+
+	go io.Copy(s.stdout, outPipe)
+	go io.Copy(s.stderr, errPipe)
+
+	return nil
+}