Fix attach stream closing issues

Fixes: #9860
Fixes: detach and attach tty mode

We never actually need to close container `stdin` after `stdout/stderr` finishes. We only need to close the `stdin` goroutine. In some cases this also means closing `stdin` but that is already controlled by the goroutine itself.

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

daemon/attach.go

@@ -179,9 +179,8 @@ func (daemon *Daemon) attach(streamConfig *StreamConfig, openStdin, stdinOnce, t
 		}
 		defer func() {
 			// Make sure stdin gets closed
-			if stdinOnce && cStdin != nil {
+			if stdin != nil {
 				stdin.Close()
-				cStdin.Close()
 			}
 			streamPipe.Close()
 			wg.Done()

integration-cli/docker_cli_attach_unix_test.go

@@ -0,0 +1,123 @@
+package main
+
+import (
+	"os/exec"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/kr/pty"
+)
+
+// #9860
+func TestAttachClosedOnContainerStop(t *testing.T) {
+	defer deleteAllContainers()
+
+	cmd := exec.Command(dockerBinary, "run", "-dti", "busybox", "sleep", "2")
+	out, _, err := runCommandWithOutput(cmd)
+	if err != nil {
+		t.Fatalf("failed to start container: %v (%v)", out, err)
+	}
+
+	id := stripTrailingCharacters(out)
+	if err := waitRun(id); err != nil {
+		t.Fatal(err)
+	}
+
+	done := make(chan struct{})
+
+	go func() {
+		defer close(done)
+
+		_, tty, err := pty.Open()
+		if err != nil {
+			t.Fatalf("could not open pty: %v", err)
+		}
+		attachCmd := exec.Command(dockerBinary, "attach", id)
+		attachCmd.Stdin = tty
+		attachCmd.Stdout = tty
+		attachCmd.Stderr = tty
+
+		if err := attachCmd.Run(); err != nil {
+			t.Fatalf("attach returned error %s", err)
+		}
+	}()
+
+	waitCmd := exec.Command(dockerBinary, "wait", id)
+	if out, _, err = runCommandWithOutput(waitCmd); err != nil {
+		t.Fatalf("error thrown while waiting for container: %s, %v", out, err)
+	}
+	select {
+	case <-done:
+	case <-time.After(attachWait):
+		t.Fatal("timed out without attach returning")
+	}
+
+	logDone("attach - return after container finished")
+}
+
+func TestAttachAfterDetach(t *testing.T) {
+	defer deleteAllContainers()
+
+	name := "detachtest"
+
+	cpty, tty, err := pty.Open()
+	if err != nil {
+		t.Fatalf("Could not open pty: %v", err)
+	}
+	cmd := exec.Command(dockerBinary, "run", "-ti", "--name", name, "busybox")
+	cmd.Stdin = tty
+	cmd.Stdout = tty
+	cmd.Stderr = tty
+
+	detached := make(chan struct{})
+	go func() {
+		if err := cmd.Run(); err != nil {
+			t.Fatalf("attach returned error %s", err)
+		}
+		close(detached)
+	}()
+
+	time.Sleep(500 * time.Millisecond)
+	cpty.Write([]byte{16})
+	time.Sleep(100 * time.Millisecond)
+	cpty.Write([]byte{17})
+
+	<-detached
+
+	cpty, tty, err = pty.Open()
+	if err != nil {
+		t.Fatalf("Could not open pty: %v", err)
+	}
+
+	cmd = exec.Command(dockerBinary, "attach", name)
+	cmd.Stdin = tty
+	cmd.Stdout = tty
+	cmd.Stderr = tty
+
+	go func() {
+		if err := cmd.Run(); err != nil {
+			t.Fatalf("attach returned error %s", err)
+		}
+		cpty.Close() // unblocks the reader in case of a failure
+	}()
+
+	time.Sleep(500 * time.Millisecond)
+	cpty.Write([]byte("\n"))
+	time.Sleep(500 * time.Millisecond)
+	bytes := make([]byte, 10)
+
+	n, err := cpty.Read(bytes)
+
+	if err != nil {
+		t.Fatalf("prompt read failed: %v", err)
+	}
+
+	if !strings.Contains(string(bytes[:n]), "/ #") {
+		t.Fatalf("failed to get a new prompt. got %s", string(bytes[:n]))
+	}
+
+	cpty.Write([]byte("exit\n"))
+
+	logDone("attach - reconnect after detaching")
+}