Update gomod and vendor

vendor/github.com/moby/buildkit/executor/oci/hosts.go

@@ -0,0 +1,78 @@
+package oci
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"github.com/docker/docker/pkg/idtools"
+	"github.com/moby/buildkit/executor"
+	"github.com/moby/buildkit/identity"
+)
+
+const hostsContent = `
+127.0.0.1	localhost buildkitsandbox
+::1	localhost ip6-localhost ip6-loopback
+`
+
+func GetHostsFile(ctx context.Context, stateDir string, extraHosts []executor.HostIP, idmap *idtools.IdentityMapping) (string, func(), error) {
+	if len(extraHosts) == 0 {
+		_, err := g.Do(ctx, stateDir, func(ctx context.Context) (interface{}, error) {
+			_, _, err := makeHostsFile(stateDir, nil, idmap)
+			return nil, err
+		})
+		if err != nil {
+			return "", nil, err
+		}
+		return filepath.Join(stateDir, "hosts"), func() {}, nil
+	}
+	return makeHostsFile(stateDir, extraHosts, idmap)
+}
+
+func makeHostsFile(stateDir string, extraHosts []executor.HostIP, idmap *idtools.IdentityMapping) (string, func(), error) {
+	p := filepath.Join(stateDir, "hosts")
+	if len(extraHosts) != 0 {
+		p += "." + identity.NewID()
+	}
+	_, err := os.Stat(p)
+	if err == nil {
+		return "", func() {}, nil
+	}
+	if !os.IsNotExist(err) {
+		return "", nil, err
+	}
+
+	b := &bytes.Buffer{}
+
+	if _, err := b.Write([]byte(hostsContent)); err != nil {
+		return "", nil, err
+	}
+
+	for _, h := range extraHosts {
+		if _, err := b.Write([]byte(fmt.Sprintf("%s\t%s\n", h.IP.String(), h.Host))); err != nil {
+			return "", nil, err
+		}
+	}
+
+	tmpPath := p + ".tmp"
+	if err := ioutil.WriteFile(tmpPath, b.Bytes(), 0644); err != nil {
+		return "", nil, err
+	}
+
+	if idmap != nil {
+		root := idmap.RootPair()
+		if err := os.Chown(tmpPath, root.UID, root.GID); err != nil {
+			return "", nil, err
+		}
+	}
+
+	if err := os.Rename(tmpPath, p); err != nil {
+		return "", nil, err
+	}
+	return p, func() {
+		os.RemoveAll(p)
+	}, nil
+}