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|
package child
import (
"fmt"
"io"
"net"
"os"
"github.com/pkg/errors"
"golang.org/x/sys/unix"
"github.com/rootless-containers/rootlesskit/pkg/msgutil"
"github.com/rootless-containers/rootlesskit/pkg/port"
"github.com/rootless-containers/rootlesskit/pkg/port/builtin/msg"
opaquepkg "github.com/rootless-containers/rootlesskit/pkg/port/builtin/opaque"
)
func NewDriver(logWriter io.Writer) port.ChildDriver {
return &childDriver{
logWriter: logWriter,
}
}
type childDriver struct {
logWriter io.Writer
}
func (d *childDriver) RunChildDriver(opaque map[string]string, quit <-chan struct{}) error {
socketPath := opaque[opaquepkg.SocketPath]
if socketPath == "" {
return errors.New("socket path not set")
}
childReadyPipePath := opaque[opaquepkg.ChildReadyPipePath]
if childReadyPipePath == "" {
return errors.New("child ready pipe path not set")
}
childReadyPipeW, err := os.OpenFile(childReadyPipePath, os.O_WRONLY, os.ModeNamedPipe)
if err != nil {
return err
}
ln, err := net.ListenUnix("unix", &net.UnixAddr{
Name: socketPath,
Net: "unix",
})
if err != nil {
return err
}
// write nothing, just close
if err = childReadyPipeW.Close(); err != nil {
return err
}
stopAccept := make(chan struct{}, 1)
go func() {
<-quit
stopAccept <- struct{}{}
ln.Close()
}()
for {
c, err := ln.AcceptUnix()
if err != nil {
select {
case <-stopAccept:
return nil
default:
}
return err
}
go func() {
if rerr := d.routine(c); rerr != nil {
rep := msg.Reply{
Error: rerr.Error(),
}
msgutil.MarshalToWriter(c, &rep)
}
c.Close()
}()
}
return nil
}
func (d *childDriver) routine(c *net.UnixConn) error {
var req msg.Request
if _, err := msgutil.UnmarshalFromReader(c, &req); err != nil {
return err
}
switch req.Type {
case msg.RequestTypeInit:
return d.handleConnectInit(c, &req)
case msg.RequestTypeConnect:
return d.handleConnectRequest(c, &req)
default:
return errors.Errorf("unknown request type %q", req.Type)
}
}
func (d *childDriver) handleConnectInit(c *net.UnixConn, req *msg.Request) error {
_, err := msgutil.MarshalToWriter(c, nil)
return err
}
func (d *childDriver) handleConnectRequest(c *net.UnixConn, req *msg.Request) error {
switch req.Proto {
case "tcp":
case "udp":
default:
return errors.Errorf("unknown proto: %q", req.Proto)
}
var dialer net.Dialer
targetConn, err := dialer.Dial(req.Proto, fmt.Sprintf("127.0.0.1:%d", req.Port))
if err != nil {
return err
}
defer targetConn.Close() // no effect on duplicated FD
targetConnFiler, ok := targetConn.(filer)
if !ok {
return errors.Errorf("unknown target connection: %+v", targetConn)
}
targetConnFile, err := targetConnFiler.File()
if err != nil {
return err
}
oob := unix.UnixRights(int(targetConnFile.Fd()))
f, err := c.File()
if err != nil {
return err
}
err = unix.Sendmsg(int(f.Fd()), []byte("dummy"), oob, nil, 0)
return err
}
// filer is implemented by *net.TCPConn and *net.UDPConn
type filer interface {
File() (f *os.File, err error)
}
|
