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package messages
import (
"fmt"
"io"
"reflect"
"github.com/rootless-containers/rootlesskit/v2/pkg/lowlevelmsgutil"
"github.com/sirupsen/logrus"
)
// Message for parent-child communication.
// Sent as JSON, with uint32le length header.
type Message struct {
Name string // Name is like "MessageParentHello". Automatically filled on [Send.
U
}
func (m *Message) FulfillName() error {
uT := reflect.TypeOf(m.U)
uV := reflect.ValueOf(m.U)
uN := uT.NumField()
for i := 0; i < uN; i++ {
uTF := uT.Field(i)
uVF := uV.Field(i)
if !uVF.IsNil() {
m.Name = uTF.Name
return nil
}
}
return fmt.Errorf("failed to fulfill the name for message %+v", m)
}
// U is a union.
type U struct {
*ParentHello
*ChildHello
*ParentInitIdmapCompleted
*ChildInitUserNSCompleted
*ParentInitNetworkDriverCompleted
*ParentInitPortDriverCompleted
}
type ParentHello struct {
}
type ChildHello struct {
}
type ParentInitIdmapCompleted struct {
}
type ChildInitUserNSCompleted struct {
}
type ParentInitNetworkDriverCompleted struct {
// Fields are empty for HostNetwork.
Dev string
IP string
Netmask int
Gateway string
DNS string
MTU int
// NetworkDriverOpaque strings are specific to driver
NetworkDriverOpaque map[string]string
}
type ParentInitPortDriverCompleted struct {
// Fields are empty for port driver "none"
PortDriverOpaque map[string]string
}
func Send(w io.Writer, m *Message) error {
if m.Name == "" {
if err := m.FulfillName(); err != nil {
return err
}
}
logrus.Debugf("Sending %+v", m)
if _, err := lowlevelmsgutil.MarshalToWriter(w, m); err != nil {
return fmt.Errorf("failed to send message %+v: %w", m, err)
}
return nil
}
func Recv(r io.Reader) (*Message, error) {
var m Message
if _, err := lowlevelmsgutil.UnmarshalFromReader(r, &m); err != nil {
return nil, err
}
logrus.Debugf("Received %+v", m)
if m.Name == "" {
return nil, fmt.Errorf("failed to parse message %+v", m)
}
return &m, nil
}
func WaitFor(r io.Reader, name string) (*Message, error) {
msg, err := Recv(r)
if err != nil {
return nil, err
}
if msg.Name != name {
return nil, fmt.Errorf("expected %q, got %+v", name, msg)
}
return msg, nil
}
func Name(x interface{}) string {
t := reflect.TypeOf(x)
if t.Kind() == reflect.Ptr {
return t.Elem().Name()
}
return t.Name()
}
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