From 6679a5faeb724f1ad060f2fdf6d189f1005924b9 Mon Sep 17 00:00:00 2001
From: Wei Fu <fuweid89@gmail.com>
Date: Wed, 10 Oct 2018 14:54:00 +0800
Subject: [PATCH 1/2] bugfix: wait for stdin creation before CloseIO

The stdin fifo of exec process is created in containerd side after
client calls Start. If the client calls CloseIO before Start call, the
stdin of exec process is still opened and wait for close.

For this case, client closes stdinCloseSync channel after Start.

Signed-off-by: Wei Fu <fuweid89@gmail.com>
(cherry picked from commit c7890f25a9eaae8d07614bd85b2b3231b03e54ec)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
---
 libcontainerd/client_daemon.go | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/libcontainerd/client_daemon.go b/libcontainerd/client_daemon.go
index 60fb3353c1b44453cb6ddd31841bbe06fc2ff07a..cb9cb43a7316f7625bca4ee58e4c7ff2d3108eae 100644
--- a/libcontainerd/client_daemon.go
+++ b/libcontainerd/client_daemon.go
@@ -328,6 +328,13 @@ func (c *client) Start(ctx context.Context, id, checkpointDir string, withStdin
 	return int(t.Pid()), nil
 }
 
+// Exec creates exec process.
+//
+// The containerd client calls Exec to register the exec config in the shim side.
+// When the client calls Start, the shim will create stdin fifo if needs. But
+// for the container main process, the stdin fifo will be created in Create not
+// the Start call. stdinCloseSync channel should be closed after Start exec
+// process.
 func (c *client) Exec(ctx context.Context, containerID, processID string, spec *specs.Process, withStdin bool, attachStdio StdioCallback) (int, error) {
 	ctr := c.getContainer(containerID)
 	if ctr == nil {
@@ -372,7 +379,9 @@ func (c *client) Exec(ctx context.Context, containerID, processID string, spec *
 	ctr.addProcess(processID, p)
 
 	// Signal c.createIO that it can call CloseIO
-	close(stdinCloseSync)
+	//
+	// the stdin of exec process will be created after p.Start in containerd
+	defer close(stdinCloseSync)
 
 	if err = p.Start(ctx); err != nil {
 		p.Delete(context.Background())

From ae6284a623bac86ac6ab718fa4a369dd8c0a3cfc Mon Sep 17 00:00:00 2001
From: Wei Fu <fuweid89@gmail.com>
Date: Thu, 11 Oct 2018 19:03:02 +0800
Subject: [PATCH 2/2] testing: add case for exec closeStdin

add regression case for the issue#37870

Signed-off-by: Wei Fu <fuweid89@gmail.com>
(cherry picked from commit 8e25f4ff6d89888a1bcd578f3f8f7aab89dce24d)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
---
 integration/container/exec_test.go | 69 ++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/integration/container/exec_test.go b/integration/container/exec_test.go
index 85f9e0591571e55b3a13f6e706991e8041d4de7c..d33301b8e3fb0c28c8dc8508f6afaf5d6efa32eb 100644
--- a/integration/container/exec_test.go
+++ b/integration/container/exec_test.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"io/ioutil"
 	"testing"
+	"time"
 
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/strslice"
@@ -15,6 +16,74 @@ import (
 	"gotest.tools/skip"
 )
 
+// TestExecWithCloseStdin adds case for moby#37870 issue.
+func TestExecWithCloseStdin(t *testing.T) {
+	skip.If(t, versions.LessThan(testEnv.DaemonAPIVersion(), "1.39"), "broken in earlier versions")
+	defer setupTest(t)()
+
+	ctx := context.Background()
+	client := request.NewAPIClient(t)
+
+	// run top with detached mode
+	cID := container.Run(t, ctx, client)
+
+	expected := "closeIO"
+	execResp, err := client.ContainerExecCreate(ctx, cID,
+		types.ExecConfig{
+			AttachStdin:  true,
+			AttachStdout: true,
+			Cmd:          strslice.StrSlice([]string{"sh", "-c", "cat && echo " + expected}),
+		},
+	)
+	assert.NilError(t, err)
+
+	resp, err := client.ContainerExecAttach(ctx, execResp.ID,
+		types.ExecStartCheck{
+			Detach: false,
+			Tty:    false,
+		},
+	)
+	assert.NilError(t, err)
+	defer resp.Close()
+
+	// close stdin to send EOF to cat
+	assert.NilError(t, resp.CloseWrite())
+
+	var (
+		waitCh = make(chan struct{})
+		resCh  = make(chan struct {
+			content string
+			err     error
+		})
+	)
+
+	go func() {
+		close(waitCh)
+		defer close(resCh)
+		r, err := ioutil.ReadAll(resp.Reader)
+
+		resCh <- struct {
+			content string
+			err     error
+		}{
+			content: string(r),
+			err:     err,
+		}
+	}()
+
+	<-waitCh
+	select {
+	case <-time.After(3 * time.Second):
+		t.Fatal("failed to read the content in time")
+	case got := <-resCh:
+		assert.NilError(t, got.err)
+
+		// NOTE: using Contains because no-tty's stream contains UX information
+		// like size, stream type.
+		assert.Assert(t, is.Contains(got.content, expected))
+	}
+}
+
 func TestExec(t *testing.T) {
 	skip.If(t, versions.LessThan(testEnv.DaemonAPIVersion(), "1.35"), "broken in earlier versions")
 	defer setupTest(t)()