stage1: dedupe shared volume path creation logic

common/common.go

@@ -18,6 +18,7 @@ package common
 
 import (
 	"bufio"
+	"errors"
 	"fmt"
 	"net"
 	"os"
@@ -37,6 +38,7 @@ import (
 
 const (
 	sharedVolumesDir = "/sharedVolumes"
+	SharedVolumePerm = os.FileMode(0755)
 	stage1Dir        = "/stage1"
 	stage2Dir        = "/opt/stage2"
 	AppsInfoDir      = "/appsinfo"
@@ -199,6 +201,23 @@ func SharedVolumesPath(root string) string {
 	return filepath.Join(root, sharedVolumesDir)
 }
 
+// CreateSharedVolumesPath ensures the sharedVolumePath for the pod root passed
+// in exists. It returns the shared volume path or an error.
+func CreateSharedVolumesPath(root string) (string, error) {
+	sharedVolPath := SharedVolumesPath(root)
+
+	if err := os.MkdirAll(sharedVolPath, SharedVolumePerm); err != nil {
+		return "", errwrap.Wrap(errors.New("could not create shared volumes directory"), err)
+	}
+	// In case it already existed and we didn't make it, ensure permissions are
+	// what the caller expects them to be.
+	if err := os.Chmod(sharedVolPath, SharedVolumePerm); err != nil {
+		return "", errwrap.Wrap(fmt.Errorf("could not change permissions of %q", sharedVolPath), err)
+	}
+
+	return sharedVolPath, nil
+}
+
 // MetadataServicePublicURL returns the public URL used to host the metadata service
 func MetadataServicePublicURL(ip net.IP, token string) string {
 	return fmt.Sprintf("http://%v:%v/%v", ip, MetadataServicePort, token)

stage1/init/common/mount.go

@@ -274,24 +274,24 @@ func BindMount(mnt fs.MountUnmounter, source, destination string, readOnly bool)
 }
 
 // ensureDestinationExists will recursively create a given mountpoint. If directories
-// are created, their permissions are initialized to stage1/init/common.SharedVolPerm
+// are created, their permissions are initialized to common.SharedVolumePerm
 func ensureDestinationExists(source, destination string) error {
 	fileInfo, err := os.Stat(source)
 	if err != nil {
 		return errwrap.Wrap(fmt.Errorf("could not stat source location: %v", source), err)
 	}
 
 	targetPathParent, _ := filepath.Split(destination)
-	if err := os.MkdirAll(targetPathParent, SharedVolPerm); err != nil {
+	if err := os.MkdirAll(targetPathParent, common.SharedVolumePerm); err != nil {
 		return errwrap.Wrap(fmt.Errorf("could not create parent directory: %v", targetPathParent), err)
 	}
 
 	if fileInfo.IsDir() {
-		if err := os.Mkdir(destination, SharedVolPerm); err != nil && !os.IsExist(err) {
+		if err := os.Mkdir(destination, common.SharedVolumePerm); err != nil && !os.IsExist(err) {
 			return errwrap.Wrap(errors.New("could not create destination directory "+destination), err)
 		}
 	} else {
-		if file, err := os.OpenFile(destination, os.O_CREATE, SharedVolPerm); err != nil {
+		if file, err := os.OpenFile(destination, os.O_CREATE, common.SharedVolumePerm); err != nil {
 			return errwrap.Wrap(errors.New("could not create destination file"), err)
 		} else {
 			file.Close()
@@ -301,12 +301,9 @@ func ensureDestinationExists(source, destination string) error {
 }
 
 func AppAddMounts(p *stage1commontypes.Pod, ra *schema.RuntimeApp, enterCmd []string) error {
-	sharedVolPath := common.SharedVolumesPath(p.Root)
-	if err := os.MkdirAll(sharedVolPath, SharedVolPerm); err != nil {
-		return errwrap.Wrap(errors.New("could not create shared volumes directory"), err)
-	}
-	if err := os.Chmod(sharedVolPath, SharedVolPerm); err != nil {
-		return errwrap.Wrap(fmt.Errorf("could not change permissions of %q", sharedVolPath), err)
+	sharedVolPath, err := common.CreateSharedVolumesPath(p.Root)
+	if err != nil {
+		return err
 	}
 
 	vols := make(map[types.ACName]types.Volume)

stage1/init/common/pod.go

@@ -43,8 +43,7 @@ import (
 
 const (
 	// FlavorFile names the file storing the pod's flavor
-	FlavorFile    = "flavor"
-	SharedVolPerm = os.FileMode(0755)
+	FlavorFile = "flavor"
 )
 
 // execEscape uses Golang's string quoting for ", \, \n, and regex for special cases
@@ -464,12 +463,9 @@ func appToNspawnArgs(p *stage1commontypes.Pod, ra *schema.RuntimeApp) ([]string,
 	appName := ra.Name
 	app := ra.App
 
-	sharedVolPath := common.SharedVolumesPath(p.Root)
-	if err := os.MkdirAll(sharedVolPath, SharedVolPerm); err != nil {
-		return nil, errwrap.Wrap(errors.New("could not create shared volumes directory"), err)
-	}
-	if err := os.Chmod(sharedVolPath, SharedVolPerm); err != nil {
-		return nil, errwrap.Wrap(fmt.Errorf("could not change permissions of %q", sharedVolPath), err)
+	sharedVolPath, err := common.CreateSharedVolumesPath(p.Root)
+	if err != nil {
+		return nil, err
 	}
 
 	vols := make(map[types.ACName]types.Volume)

stage1/init/kvm.go

@@ -56,12 +56,9 @@ func KvmNetworkingToSystemd(p *stage1commontypes.Pod, n *networking.Networking)
 func mountSharedVolumes(p *stage1commontypes.Pod, ra *schema.RuntimeApp) error {
 	appName := ra.Name
 
-	sharedVolPath := common.SharedVolumesPath(p.Root)
-	if err := os.MkdirAll(sharedVolPath, stage1initcommon.SharedVolPerm); err != nil {
-		return errwrap.Wrap(errors.New("could not create shared volumes directory"), err)
-	}
-	if err := os.Chmod(sharedVolPath, stage1initcommon.SharedVolPerm); err != nil {
-		return errwrap.Wrap(fmt.Errorf("could not change permissions of %q", sharedVolPath), err)
+	sharedVolPath, err := common.CreateSharedVolumesPath(p.Root)
+	if err != nil {
+		return err
 	}
 
 	imageManifest := p.Images[appName.String()]
@@ -149,16 +146,16 @@ func ensureDestinationExists(source, destination string) error {
 	}
 
 	targetPathParent, _ := filepath.Split(destination)
-	if err := os.MkdirAll(targetPathParent, stage1initcommon.SharedVolPerm); err != nil {
+	if err := os.MkdirAll(targetPathParent, common.SharedVolumePerm); err != nil {
 		return errwrap.Wrap(fmt.Errorf("could not create parent directory: %v", targetPathParent), err)
 	}
 
 	if fileInfo.IsDir() {
-		if err := os.Mkdir(destination, stage1initcommon.SharedVolPerm); !os.IsExist(err) {
+		if err := os.Mkdir(destination, common.SharedVolumePerm); !os.IsExist(err) {
 			return err
 		}
 	} else {
-		if file, err := os.OpenFile(destination, os.O_CREATE, stage1initcommon.SharedVolPerm); err != nil {
+		if file, err := os.OpenFile(destination, os.O_CREATE, common.SharedVolumePerm); err != nil {
 			return err
 		} else {
 			file.Close()