Allow setting the uid & gid of the io pipes

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>

vendor/github.com/containerd/go-runc/io.go

@@ -4,6 +4,9 @@ import (
 	"io"
 	"os"
 	"os/exec"
+
+	"github.com/pkg/errors"
+	"golang.org/x/sys/unix"
 )
 
 type IO interface {
@@ -19,7 +22,7 @@ type StartCloser interface {
 }
 
 // NewPipeIO creates pipe pairs to be used with runc
-func NewPipeIO() (i IO, err error) {
+func NewPipeIO(uid, gid int) (i IO, err error) {
 	var pipes []*pipe
 	// cleanup in case of an error
 	defer func() {
@@ -34,18 +37,27 @@ func NewPipeIO() (i IO, err error) {
 		return nil, err
 	}
 	pipes = append(pipes, stdin)
+	if err = unix.Fchown(int(stdin.r.Fd()), uid, gid); err != nil {
+		return nil, errors.Wrap(err, "failed to chown stdin")
+	}
 
 	stdout, err := newPipe()
 	if err != nil {
 		return nil, err
 	}
 	pipes = append(pipes, stdout)
+	if err = unix.Fchown(int(stdout.w.Fd()), uid, gid); err != nil {
+		return nil, errors.Wrap(err, "failed to chown stdout")
+	}
 
 	stderr, err := newPipe()
 	if err != nil {
 		return nil, err
 	}
 	pipes = append(pipes, stderr)
+	if err = unix.Fchown(int(stderr.w.Fd()), uid, gid); err != nil {
+		return nil, errors.Wrap(err, "failed to chown stderr")
+	}
 
 	return &pipeIO{
 		in:  stdin,