4 files changed, 47 insertions, 23 deletions
diff --git a/pkg/varlinkapi/attach.go b/pkg/varlinkapi/attach.go
index 2234899a5..f292bbbf8 100644
--- a/pkg/varlinkapi/attach.go
+++ b/pkg/varlinkapi/attach.go
@@ -45,22 +45,24 @@ func (i *LibpodAPI) Attach(call iopodman.VarlinkCall, name string, detachKeys st
 	var finalErr error
 	resize := make(chan remotecommand.TerminalSize)
 	errChan := make(chan error)
+	varlink := VarlinkCall{&call}
 
-	if !call.WantsUpgrade() {
-		return call.ReplyErrorOccurred("client must use upgraded connection to attach")
+	if err := varlink.RequiresUpgrade(); err != nil {
+		return varlink.ReplyErrorOccurred(err.Error())
 	}
+
 	ctr, err := i.Runtime.LookupContainer(name)
 	if err != nil {
-		return call.ReplyErrorOccurred(err.Error())
+		return varlink.ReplyErrorOccurred(err.Error())
 	}
 	state, err := ctr.State()
 	if err != nil {
-		return call.ReplyErrorOccurred(err.Error())
+		return varlink.ReplyErrorOccurred(err.Error())
 	}
 	if !start && state != libpod.ContainerStateRunning {
-		return call.ReplyErrorOccurred("container must be running to attach")
+		return varlink.ReplyErrorOccurred("container must be running to attach")
 	}
-	call.Reply(nil)
+
 	reader, writer, _, pw, streams := setupStreams(call)
 
 	go func() {
@@ -81,7 +83,7 @@ func (i *LibpodAPI) Attach(call iopodman.VarlinkCall, name string, detachKeys st
 	quitWriter := virtwriter.NewVirtWriteCloser(writer, virtwriter.Quit)
 	_, err = quitWriter.Write([]byte("HANG-UP"))
 	// TODO error handling is not quite right here yet
-	return call.Writer.Flush()
+	return varlink.Writer.Flush()
 }
 
 func attach(ctr *libpod.Container, streams *libpod.AttachStreams, detachKeys string, resize chan remotecommand.TerminalSize, errChan chan error) error {
diff --git a/pkg/varlinkapi/config.go b/pkg/varlinkapi/config.go
index e75170547..9952c2be1 100644
--- a/pkg/varlinkapi/config.go
+++ b/pkg/varlinkapi/config.go
@@ -21,3 +21,7 @@ func New(cli *cliconfig.PodmanCommand, runtime *libpod.Runtime) *iopodman.Varlin
 	lp := LibpodAPI{Cli: cli.Command, Runtime: runtime}
 	return iopodman.VarlinkNew(&lp)
 }
+
+type VarlinkCall struct {
+	*iopodman.VarlinkCall
+}
diff --git a/pkg/varlinkapi/transfers.go b/pkg/varlinkapi/transfers.go
index 96f76bcdc..7b38ec5e6 100644
--- a/pkg/varlinkapi/transfers.go
+++ b/pkg/varlinkapi/transfers.go
@@ -15,58 +15,61 @@ import (
 
 // SendFile allows a client to send a file to the varlink server
 func (i *LibpodAPI) SendFile(call iopodman.VarlinkCall, ftype string, length int64) error {
-	if !call.WantsUpgrade() {
-		return call.ReplyErrorOccurred("client must use upgraded connection to send files")
+	varlink := VarlinkCall{&call}
+	if err := varlink.RequiresUpgrade(); err != nil {
+		return varlink.ReplyErrorOccurred(err.Error())
 	}
 
 	outputFile, err := ioutil.TempFile("", "varlink_send")
 	if err != nil {
-		return call.ReplyErrorOccurred(err.Error())
+		return varlink.ReplyErrorOccurred(err.Error())
 	}
 	defer outputFile.Close()
 
-	if err = call.ReplySendFile(outputFile.Name()); err != nil {
-		return call.ReplyErrorOccurred(err.Error())
+	if err = varlink.ReplySendFile(outputFile.Name()); err != nil {
+		return varlink.ReplyErrorOccurred(err.Error())
 	}
 
 	writer := bufio.NewWriter(outputFile)
 	defer writer.Flush()
 
-	reader := call.Call.Reader
+	reader := varlink.Call.Reader
 	if _, err := io.CopyN(writer, reader, length); err != nil {
 		return err
 	}
 
 	logrus.Debugf("successfully received %s", outputFile.Name())
 	// Send an ACK to the client
-	call.Call.Writer.WriteString(fmt.Sprintf("%s:", outputFile.Name()))
-	call.Call.Writer.Flush()
+	varlink.Call.Writer.WriteString(fmt.Sprintf("%s:", outputFile.Name()))
+	varlink.Call.Writer.Flush()
 	return nil
 
 }
 
 // ReceiveFile allows the varlink server to send a file to a client
 func (i *LibpodAPI) ReceiveFile(call iopodman.VarlinkCall, filepath string, delete bool) error {
-	if !call.WantsUpgrade() {
-		return call.ReplyErrorOccurred("client must use upgraded connection to send files")
+	varlink := VarlinkCall{&call}
+	if err := varlink.RequiresUpgrade(); err != nil {
+		return varlink.ReplyErrorOccurred(err.Error())
 	}
+
 	fs, err := os.Open(filepath)
 	if err != nil {
-		return call.ReplyErrorOccurred(err.Error())
+		return varlink.ReplyErrorOccurred(err.Error())
 	}
 	fileInfo, err := fs.Stat()
 	if err != nil {
-		return call.ReplyErrorOccurred(err.Error())
+		return varlink.ReplyErrorOccurred(err.Error())
 	}
 
 	// Send the file length down to client
 	// Varlink connection upraded
-	if err = call.ReplyReceiveFile(fileInfo.Size()); err != nil {
-		return call.ReplyErrorOccurred(err.Error())
+	if err = varlink.ReplyReceiveFile(fileInfo.Size()); err != nil {
+		return varlink.ReplyErrorOccurred(err.Error())
 	}
 
 	reader := bufio.NewReader(fs)
-	_, err = reader.WriteTo(call.Writer)
+	_, err = reader.WriteTo(varlink.Writer)
 	if err != nil {
 		return err
 	}
@@ -75,5 +78,5 @@ func (i *LibpodAPI) ReceiveFile(call iopodman.VarlinkCall, filepath string, dele
 			return err
 		}
 	}
-	return call.Writer.Flush()
+	return varlink.Writer.Flush()
 }
diff --git a/pkg/varlinkapi/util.go b/pkg/varlinkapi/util.go
index 8716c963a..a9f1e20a1 100644
--- a/pkg/varlinkapi/util.go
+++ b/pkg/varlinkapi/util.go
@@ -13,6 +13,11 @@ import (
 	"github.com/containers/libpod/cmd/podman/varlink"
 	"github.com/containers/libpod/libpod"
 	"github.com/containers/storage/pkg/archive"
+	"github.com/pkg/errors"
+)
+
+var (
+	ErrUpgradedConnectionRequired = errors.New("peer must use upgraded connection for operation")
 )
 
 // getContext returns a non-nil, empty context
@@ -195,3 +200,13 @@ func makePsOpts(inOpts iopodman.PsOpts) shared.PsOptions {
 		Sync:      derefBool(inOpts.Sync),
 	}
 }
+
+// RequiresUpgrade tests if varlink connection has been marked for upgrade.
+func (v *VarlinkCall) RequiresUpgrade() error {
+	if v.WantsUpgrade() {
+		// A nil is sent to the peer as required by the varlink protocol.
+		return v.Reply(nil)
+	} else {
+		return ErrUpgradedConnectionRequired
+	}
+}