bugfix: use same memory in ringbuffer

ContainerIO' backend will read data into ringbuffer. But the data blocks
use the same memory so that the comming data will override the previous
one. Need to copy data before push into ringbuffer.

Signed-off-by: Wei Fu <[email protected]>

daemon/containerio/container_io.go

@@ -356,7 +356,16 @@ func (cio *ContainerIO) converge(name, id string, in io.Reader) {
 			break
 		}
 
-		cover, err := cio.ring.Push(data[:n])
+		// FIXME(fuwei): In case that the data slice is reused by the writer,
+		// we should copy the data before we push it into the ringbuffer.
+		// The previous data shares the same address with the coming data.
+		// If we don't copy the data and the previous data isn't consumed by
+		// ringbuf pop action, the incoming data will override the previous data
+		// in the ringbuf.
+		copyData := make([]byte, n)
+		copy(copyData, data[:n])
+
+		cover, err := cio.ring.Push(copyData)
 		if err != nil {
 			break
 		}

test/api_container_exec_start_test.go

@@ -3,10 +3,13 @@ package main
 import (
 	"bufio"
 	"bytes"
+	"crypto/rand"
+	"encoding/hex"
 	"io"
 	"net"
 	"strings"
 
+	"github.com/alibaba/pouch/apis/types"
 	"github.com/alibaba/pouch/test/environment"
 	"github.com/alibaba/pouch/test/request"
 
@@ -46,6 +49,62 @@ func checkEchoSuccess(c *check.C, tty bool, conn net.Conn, br *bufio.Reader, exp
 	c.Assert(strings.TrimSpace(buf.String()), check.Equals, exp, check.Commentf("Expected %s, got %s", exp, buf.String()))
 }
 
+func (suite *APIContainerExecStartSuite) TestContainerExecWithLongInput(c *check.C) {
+	cname := "TestContainerExecWithLongInput"
+
+	CreateBusyboxContainerOk(c, cname)
+	defer DelContainerForceMultyTime(c, cname)
+	StartContainerOk(c, cname)
+
+	var execID string
+
+	// create exec
+	{
+		// echo the input
+		obj := map[string]interface{}{
+			"Cmd":          []string{"cat"},
+			"AttachStderr": true,
+			"AttachStdout": true,
+			"AttachStdin":  true,
+			"Tty":          true, // avoid to use docker stdcopy
+		}
+
+		body := request.WithJSONBody(obj)
+		resp, err := request.Post("/containers/"+cname+"/exec", body)
+		c.Assert(err, check.IsNil)
+		CheckRespStatus(c, resp, 201)
+
+		var got types.ExecCreateResp
+		c.Assert(request.DecodeBody(&got, resp.Body), check.IsNil)
+		execID = got.ID
+	}
+
+	// start exec
+	{
+		obj := map[string]interface{}{
+			"Tty": true, // avoid to use docker stdcopy
+		}
+		resp, conn, br, err := request.Hijack("/exec/"+execID+"/start", request.WithJSONBody(obj))
+		c.Assert(err, check.IsNil)
+		CheckRespStatus(c, resp, 200)
+		defer conn.Close()
+
+		// input 256 chars
+		input := make([]byte, 256)
+		_, err = rand.Read(input)
+		c.Assert(err, check.IsNil)
+		content := hex.EncodeToString(input)
+
+		_, err = conn.Write([]byte(content + "\n"))
+		c.Assert(err, check.IsNil)
+
+		reader := bufio.NewReader(br)
+		got, _, err := reader.ReadLine()
+		c.Assert(err, check.IsNil)
+		c.Assert(string(got), check.Equals, content)
+	}
+}
+
 // TestContainerExecStartWithoutUpgrade tests start exec without upgrade which will return 200 OK.
 func (suite *APIContainerExecStartSuite) TestContainerExecStartWithoutUpgrade(c *check.C) {
 	cname := "TestContainerCreateExecStartWithoutUpgrade"