criu swrk: return child error to caller

main.go

@@ -61,13 +61,19 @@
 }
 
 // Cleanup cleans up
-func (c *Criu) Cleanup() {
+func (c *Criu) Cleanup() error {
+	var errs []error
 	if c.swrkCmd != nil {
-		c.swrkSk.Close()
+		if err := c.swrkSk.Close(); err != nil {
+			errs = append(errs, err)
+		}
 		c.swrkSk = nil
-		_ = c.swrkCmd.Wait()
+		if err := c.swrkCmd.Wait(); err != nil {
+			errs = append(errs, fmt.Errorf("criu swrk failed: %w", err))
+		}
 		c.swrkCmd = nil
 	}
+	return errors.Join(errs...)
 }
 
 func (c *Criu) sendAndRecv(reqB []byte) ([]byte, int, error) {
@@ -99,9 +105,7 @@
 	return nil
 }
 
-func (c *Criu) doSwrkWithResp(reqType rpc.CriuReqType, opts *rpc.CriuOpts, nfy Notify, features *rpc.CriuFeatures) (*rpc.CriuResp, error) {
-	var resp *rpc.CriuResp
-
+func (c *Criu) doSwrkWithResp(reqType rpc.CriuReqType, opts *rpc.CriuOpts, nfy Notify, features *rpc.CriuFeatures) (resp *rpc.CriuResp, retErr error) {
 	req := rpc.CriuReq{
 		Type: &reqType,
 		Opts: opts,
@@ -121,7 +125,13 @@
 			return nil, err
 		}
 
-		defer c.Cleanup()
+		defer func() {
+			// append any cleanup errors to the returned error
+			err := c.Cleanup()
+			if err != nil {
+				retErr = errors.Join(retErr, err)
+			}
+		}()
 	}
 
 	for {

phaul/client.go

@@ -1,6 +1,7 @@
 package phaul
 
 import (
+	"errors"
 	"fmt"
 
 	"github.com/checkpoint-restore/go-criu/v7"
@@ -55,7 +56,7 @@
 }
 
 // Migrate function
-func (pc *Client) Migrate() error {
+func (pc *Client) Migrate() (retErr error) {
 	criu := criu.MakeCriu()
 	psi := rpc.CriuPageServerInfo{
 		Fd: proto.Int32(int32(pc.cfg.Memfd)),
@@ -72,7 +73,13 @@
 		return err
 	}
 
-	defer criu.Cleanup()
+	defer func() {
+		// append any cleanup errors to the returned error
+		err := criu.Cleanup()
+		if err != nil {
+			retErr = errors.Join(retErr, err)
+		}
+	}()
 
 	imgs, err := preparePhaulImages(pc.cfg.Wdir)
 	if err != nil {

test/main.go

@@ -202,7 +202,10 @@ func main() {
 			log.Fatalln("dump failed: ", err)
 		}
 
-		c.Cleanup()
+		err = c.Cleanup()
+		if err != nil {
+			log.Fatalln("cleanup failed: ", err)
+		}
 	case "restore":
 		log.Println("Restoring")
 		img, err := os.Open(os.Args[2])