Fixing bug in AttachStreams that would fail to close StdIn

During a docker exec, if no TTY is specified, the code would still leave stdin open instead of closing it. This change adds handling for the execConfig TTY bool that mirrors what is already done for container config. (Updated this change to be Windows only.)

Signed-off-by: Stefan J. Wernli <swernli@microsoft.com>

daemon/monitor.go

@@ -8,6 +8,7 @@ import (
 	"strconv"
 
 	"github.com/Sirupsen/logrus"
+	"github.com/docker/docker/daemon/exec"
 	"github.com/docker/docker/libcontainerd"
 	"github.com/docker/docker/runconfig"
 )
@@ -103,10 +104,15 @@ func (daemon *Daemon) StateChanged(id string, e libcontainerd.StateInfo) error {
 
 // AttachStreams is called by libcontainerd to connect the stdio.
 func (daemon *Daemon) AttachStreams(id string, iop libcontainerd.IOPipe) error {
-	var s *runconfig.StreamConfig
+	var (
+		s  *runconfig.StreamConfig
+		ec *exec.Config
+	)
+
 	c := daemon.containers.Get(id)
 	if c == nil {
-		ec, err := daemon.getExecConfig(id)
+		var err error
+		ec, err = daemon.getExecConfig(id)
 		if err != nil {
 			return fmt.Errorf("no such exec/container: %s", id)
 		}
@@ -127,7 +133,10 @@ func (daemon *Daemon) AttachStreams(id string, iop libcontainerd.IOPipe) error {
 			}()
 		}
 	} else {
-		if c != nil && !c.Config.Tty {
+		//TODO(swernli): On Windows, not closing stdin when no tty is requested by the exec Config
+		// results in a hang. We should re-evaluate generalizing this fix for all OSes if
+		// we can determine that is the right thing to do more generally.
+		if (c != nil && !c.Config.Tty) || (ec != nil && !ec.Tty && runtime.GOOS == "windows") {
 			// tty is enabled, so dont close containerd's iopipe stdin.
 			if iop.Stdin != nil {
 				iop.Stdin.Close()