Initial checkin from CRI-O repo

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

vendor/github.com/containers/storage/drivers/vfs/driver.go

@@ -0,0 +1,155 @@
+package vfs
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/containers/storage/drivers"
+	"github.com/containers/storage/pkg/chrootarchive"
+	"github.com/containers/storage/pkg/idtools"
+	"github.com/containers/storage/pkg/system"
+	"github.com/opencontainers/selinux/go-selinux/label"
+)
+
+var (
+	// CopyWithTar defines the copy method to use.
+	CopyWithTar = chrootarchive.NewArchiver(nil).CopyWithTar
+)
+
+func init() {
+	graphdriver.Register("vfs", Init)
+}
+
+// Init returns a new VFS driver.
+// This sets the home directory for the driver and returns NaiveDiffDriver.
+func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) {
+	d := &Driver{
+		homes:      []string{home},
+		idMappings: idtools.NewIDMappingsFromMaps(uidMaps, gidMaps),
+	}
+	rootIDs := d.idMappings.RootPair()
+	if err := idtools.MkdirAllAndChown(home, 0700, rootIDs); err != nil {
+		return nil, err
+	}
+	for _, option := range options {
+		if strings.HasPrefix(option, "vfs.imagestore=") {
+			d.homes = append(d.homes, strings.Split(option[15:], ",")...)
+		}
+	}
+	return graphdriver.NewNaiveDiffDriver(d, uidMaps, gidMaps), nil
+}
+
+// Driver holds information about the driver, home directory of the driver.
+// Driver implements graphdriver.ProtoDriver. It uses only basic vfs operations.
+// In order to support layering, files are copied from the parent layer into the new layer. There is no copy-on-write support.
+// Driver must be wrapped in NaiveDiffDriver to be used as a graphdriver.Driver
+type Driver struct {
+	homes      []string
+	idMappings *idtools.IDMappings
+}
+
+func (d *Driver) String() string {
+	return "vfs"
+}
+
+// Status is used for implementing the graphdriver.ProtoDriver interface. VFS does not currently have any status information.
+func (d *Driver) Status() [][2]string {
+	return nil
+}
+
+// Metadata is used for implementing the graphdriver.ProtoDriver interface. VFS does not currently have any meta data.
+func (d *Driver) Metadata(id string) (map[string]string, error) {
+	return nil, nil
+}
+
+// Cleanup is used to implement graphdriver.ProtoDriver. There is no cleanup required for this driver.
+func (d *Driver) Cleanup() error {
+	return nil
+}
+
+// CreateReadWrite creates a layer that is writable for use as a container
+// file system.
+func (d *Driver) CreateReadWrite(id, parent string, opts *graphdriver.CreateOpts) error {
+	return d.Create(id, parent, opts)
+}
+
+// Create prepares the filesystem for the VFS driver and copies the directory for the given id under the parent.
+func (d *Driver) Create(id, parent string, opts *graphdriver.CreateOpts) error {
+	if opts != nil && len(opts.StorageOpt) != 0 {
+		return fmt.Errorf("--storage-opt is not supported for vfs")
+	}
+
+	dir := d.dir(id)
+	rootIDs := d.idMappings.RootPair()
+	if err := idtools.MkdirAllAndChown(filepath.Dir(dir), 0700, rootIDs); err != nil {
+		return err
+	}
+	if err := idtools.MkdirAndChown(dir, 0755, rootIDs); err != nil {
+		return err
+	}
+	labelOpts := []string{"level:s0"}
+	if _, mountLabel, err := label.InitLabels(labelOpts); err == nil {
+		label.SetFileLabel(dir, mountLabel)
+	}
+	if parent == "" {
+		return nil
+	}
+	parentDir, err := d.Get(parent, "")
+	if err != nil {
+		return fmt.Errorf("%s: %s", parent, err)
+	}
+	return CopyWithTar(parentDir, dir)
+}
+
+func (d *Driver) dir(id string) string {
+	for i, home := range d.homes {
+		if i > 0 {
+			home = filepath.Join(home, d.String())
+		}
+		candidate := filepath.Join(home, "dir", filepath.Base(id))
+		fi, err := os.Stat(candidate)
+		if err == nil && fi.IsDir() {
+			return candidate
+		}
+	}
+	return filepath.Join(d.homes[0], "dir", filepath.Base(id))
+}
+
+// Remove deletes the content from the directory for a given id.
+func (d *Driver) Remove(id string) error {
+	return system.EnsureRemoveAll(d.dir(id))
+}
+
+// Get returns the directory for the given id.
+func (d *Driver) Get(id, mountLabel string) (string, error) {
+	dir := d.dir(id)
+	if st, err := os.Stat(dir); err != nil {
+		return "", err
+	} else if !st.IsDir() {
+		return "", fmt.Errorf("%s: not a directory", dir)
+	}
+	return dir, nil
+}
+
+// Put is a noop for vfs that return nil for the error, since this driver has no runtime resources to clean up.
+func (d *Driver) Put(id string) error {
+	// The vfs driver has no runtime resources (e.g. mounts)
+	// to clean up, so we don't need anything here
+	return nil
+}
+
+// Exists checks to see if the directory exists for the given id.
+func (d *Driver) Exists(id string) bool {
+	_, err := os.Stat(d.dir(id))
+	return err == nil
+}
+
+// AdditionalImageStores returns additional image stores supported by the driver
+func (d *Driver) AdditionalImageStores() []string {
+	if len(d.homes) > 1 {
+		return d.homes[1:]
+	}
+	return nil
+}