Remove ToHost and replace it with IDMappings.ToHost

Signed-off-by: Daniel Nephin <dnephin@docker.com>

pkg/archive/archive.go

@@ -413,15 +413,11 @@ func (ta *tarAppender) addTarFile(path, name string) error {
 	//writing tar headers/files. We skip whiteout files because they were written
 	//by the kernel and already have proper ownership relative to the host
 	if !strings.HasPrefix(filepath.Base(hdr.Name), WhiteoutPrefix) && !ta.IDMappings.Empty() {
-		uid, gid, err := getFileUIDGID(fi.Sys())
+		fileIDPair, err := getFileUIDGID(fi.Sys())
 		if err != nil {
 			return err
 		}
-		hdr.Uid, err = ta.IDMappings.UIDToContainer(uid)
-		if err != nil {
-			return err
-		}
-		hdr.Gid, err = ta.IDMappings.GIDToContainer(gid)
+		hdr.Uid, hdr.Gid, err = ta.IDMappings.ToContainer(fileIDPair)
 		if err != nil {
 			return err
 		}
@@ -806,7 +802,8 @@ func Unpack(decompressedArchive io.Reader, dest string, options *TarOptions) err
 	defer pools.BufioReader32KPool.Put(trBuf)
 
 	var dirs []*tar.Header
-	remappedRootUID, remappedRootGID, err := idtools.GetRootUIDGID(options.UIDMaps, options.GIDMaps)
+	idMappings := idtools.NewIDMappingsFromMaps(options.UIDMaps, options.GIDMaps)
+	rootIDs, err := idMappings.RootPair()
 	if err != nil {
 		return err
 	}
@@ -843,7 +840,7 @@ loop:
 			parent := filepath.Dir(hdr.Name)
 			parentPath := filepath.Join(dest, parent)
 			if _, err := os.Lstat(parentPath); err != nil && os.IsNotExist(err) {
-				err = idtools.MkdirAllNewAs(parentPath, 0777, remappedRootUID, remappedRootGID)
+				err = idtools.MkdirAllAndChownNew(parentPath, 0777, rootIDs)
 				if err != nil {
 					return err
 				}
@@ -888,26 +885,8 @@ loop:
 		}
 		trBuf.Reset(tr)
 
-		// if the options contain a uid & gid maps, convert header uid/gid
-		// entries using the maps such that lchown sets the proper mapped
-		// uid/gid after writing the file. We only perform this mapping if
-		// the file isn't already owned by the remapped root UID or GID, as
-		// that specific uid/gid has no mapping from container -> host, and
-		// those files already have the proper ownership for inside the
-		// container.
-		if hdr.Uid != remappedRootUID {
-			xUID, err := idtools.ToHost(hdr.Uid, options.UIDMaps)
-			if err != nil {
-				return err
-			}
-			hdr.Uid = xUID
-		}
-		if hdr.Gid != remappedRootGID {
-			xGID, err := idtools.ToHost(hdr.Gid, options.GIDMaps)
-			if err != nil {
-				return err
-			}
-			hdr.Gid = xGID
+		if err := remapIDs(idMappings, hdr); err != nil {
+			return err
 		}
 
 		if whiteoutConverter != nil {
@@ -1083,26 +1062,10 @@ func (archiver *Archiver) CopyFileWithTar(src, dst string) (err error) {
 		hdr.Name = filepath.Base(dst)
 		hdr.Mode = int64(chmodTarEntry(os.FileMode(hdr.Mode)))
 
-		remappedRootIDs, err := archiver.IDMappings.RootPair()
-		if err != nil {
+		if err := remapIDs(archiver.IDMappings, hdr); err != nil {
 			return err
 		}
 
-		// only perform mapping if the file being copied isn't already owned by the
-		// uid or gid of the remapped root in the container
-		if remappedRootIDs.UID != hdr.Uid {
-			hdr.Uid, err = archiver.IDMappings.UIDToHost(hdr.Uid)
-			if err != nil {
-				return err
-			}
-		}
-		if remappedRootIDs.GID != hdr.Gid {
-			hdr.Gid, err = archiver.IDMappings.GIDToHost(hdr.Gid)
-			if err != nil {
-				return err
-			}
-		}
-
 		tw := tar.NewWriter(w)
 		defer tw.Close()
 		if err := tw.WriteHeader(hdr); err != nil {
@@ -1126,6 +1089,12 @@ func (archiver *Archiver) CopyFileWithTar(src, dst string) (err error) {
 	return err
 }
 
+func remapIDs(idMappings *idtools.IDMappings, hdr *tar.Header) error {
+	ids, err := idMappings.ToHost(idtools.IDPair{UID: hdr.Uid, GID: hdr.Gid})
+	hdr.Uid, hdr.Gid = ids.UID, ids.GID
+	return err
+}
+
 // cmdStream executes a command, and returns its stdout as a stream.
 // If the command fails to run or doesn't complete successfully, an error
 // will be returned, including anything written on stderr.

pkg/archive/archive_unix.go

@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"syscall"
 
+	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/system"
 	rsystem "github.com/opencontainers/runc/libcontainer/system"
 )
@@ -72,13 +73,13 @@ func getInodeFromStat(stat interface{}) (inode uint64, err error) {
 	return
 }
 
-func getFileUIDGID(stat interface{}) (int, int, error) {
+func getFileUIDGID(stat interface{}) (idtools.IDPair, error) {
 	s, ok := stat.(*syscall.Stat_t)
 
 	if !ok {
-		return -1, -1, errors.New("cannot convert stat value to syscall.Stat_t")
+		return idtools.IDPair{}, errors.New("cannot convert stat value to syscall.Stat_t")
 	}
-	return int(s.Uid), int(s.Gid), nil
+	return idtools.IDPair{UID: int(s.Uid), GID: int(s.Gid)}, nil
 }
 
 func major(device uint64) uint64 {

pkg/archive/archive_windows.go

@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/longpath"
 )
 
@@ -72,7 +73,7 @@ func handleLChmod(hdr *tar.Header, path string, hdrInfo os.FileInfo) error {
 	return nil
 }
 
-func getFileUIDGID(stat interface{}) (int, int, error) {
+func getFileUIDGID(stat interface{}) (idtools.IDPair, error) {
 	// no notion of file ownership mapping yet on Windows
-	return 0, 0, nil
+	return idtools.IDPair{0, 0}, nil
 }

pkg/archive/diff.go

@@ -33,10 +33,7 @@ func UnpackLayer(dest string, layer io.Reader, options *TarOptions) (size int64,
 	if options.ExcludePatterns == nil {
 		options.ExcludePatterns = []string{}
 	}
-	remappedRootUID, remappedRootGID, err := idtools.GetRootUIDGID(options.UIDMaps, options.GIDMaps)
-	if err != nil {
-		return 0, err
-	}
+	idMappings := idtools.NewIDMappingsFromMaps(options.UIDMaps, options.GIDMaps)
 
 	aufsTempdir := ""
 	aufsHardlinks := make(map[string]*tar.Header)
@@ -195,27 +192,10 @@ func UnpackLayer(dest string, layer io.Reader, options *TarOptions) (size int64,
 				srcData = tmpFile
 			}
 
-			// if the options contain a uid & gid maps, convert header uid/gid
-			// entries using the maps such that lchown sets the proper mapped
-			// uid/gid after writing the file. We only perform this mapping if
-			// the file isn't already owned by the remapped root UID or GID, as
-			// that specific uid/gid has no mapping from container -> host, and
-			// those files already have the proper ownership for inside the
-			// container.
-			if srcHdr.Uid != remappedRootUID {
-				xUID, err := idtools.ToHost(srcHdr.Uid, options.UIDMaps)
-				if err != nil {
-					return 0, err
-				}
-				srcHdr.Uid = xUID
-			}
-			if srcHdr.Gid != remappedRootGID {
-				xGID, err := idtools.ToHost(srcHdr.Gid, options.GIDMaps)
-				if err != nil {
-					return 0, err
-				}
-				srcHdr.Gid = xGID
+			if err := remapIDs(idMappings, srcHdr); err != nil {
+				return 0, err
 			}
+
 			if err := createTarFile(path, dest, srcHdr, srcData, true, nil, options.InUserNS); err != nil {
 				return 0, err
 			}

pkg/idtools/idtools.go

@@ -80,21 +80,13 @@ func MkdirAllAndChownNew(path string, mode os.FileMode, ids IDPair) error {
 // GetRootUIDGID retrieves the remapped root uid/gid pair from the set of maps.
 // If the maps are empty, then the root uid/gid will default to "real" 0/0
 func GetRootUIDGID(uidMap, gidMap []IDMap) (int, int, error) {
-	var uid, gid int
-
-	if uidMap != nil {
-		xUID, err := ToHost(0, uidMap)
-		if err != nil {
-			return -1, -1, err
-		}
-		uid = xUID
+	uid, err := toHost(0, uidMap)
+	if err != nil {
+		return -1, -1, err
 	}
-	if gidMap != nil {
-		xGID, err := ToHost(0, gidMap)
-		if err != nil {
-			return -1, -1, err
-		}
-		gid = xGID
+	gid, err := toHost(0, gidMap)
+	if err != nil {
+		return -1, -1, err
 	}
 	return uid, gid, nil
 }
@@ -115,11 +107,10 @@ func toContainer(hostID int, idMap []IDMap) (int, error) {
 	return -1, fmt.Errorf("Host ID %d cannot be mapped to a container ID", hostID)
 }
 
-// ToHost takes an id mapping and a remapped ID, and translates the
+// toHost takes an id mapping and a remapped ID, and translates the
 // ID to the mapped host ID. If no map is provided, then the translation
 // assumes a 1-to-1 mapping and returns the passed in id #
-// Depercated: use IDMappings.UIDToHost and IDMappings.GIDToHost
-func ToHost(contID int, idMap []IDMap) (int, error) {
+func toHost(contID int, idMap []IDMap) (int, error) {
 	if idMap == nil {
 		return contID, nil
 	}
@@ -181,24 +172,35 @@ func (i *IDMappings) RootPair() (IDPair, error) {
 	return IDPair{UID: uid, GID: gid}, err
 }
 
-// UIDToHost returns the host UID for the container uid
-func (i *IDMappings) UIDToHost(uid int) (int, error) {
-	return ToHost(uid, i.uids)
-}
+// ToHost returns the host UID and GID for the container uid, gid.
+// Remapping is only performed if the ids aren't already the remapped root ids
+func (i *IDMappings) ToHost(pair IDPair) (IDPair, error) {
+	target, err := i.RootPair()
+	if err != nil {
+		return IDPair{}, err
+	}
 
-// GIDToHost returns the host GID for the container gid
-func (i *IDMappings) GIDToHost(gid int) (int, error) {
-	return ToHost(gid, i.gids)
-}
+	if pair.UID != target.UID {
+		target.UID, err = toHost(pair.UID, i.uids)
+		if err != nil {
+			return target, err
+		}
+	}
 
-// UIDToContainer returns the container UID for the host uid
-func (i *IDMappings) UIDToContainer(uid int) (int, error) {
-	return toContainer(uid, i.uids)
+	if pair.GID != target.GID {
+		target.GID, err = toHost(pair.GID, i.gids)
+	}
+	return target, err
 }
 
-// GIDToContainer returns the container GID for the host gid
-func (i *IDMappings) GIDToContainer(gid int) (int, error) {
-	return toContainer(gid, i.gids)
+// ToContainer returns the container UID and GID for the host uid and gid
+func (i *IDMappings) ToContainer(pair IDPair) (int, int, error) {
+	uid, err := toContainer(pair.UID, i.uids)
+	if err != nil {
+		return -1, -1, err
+	}
+	gid, err := toContainer(pair.GID, i.gids)
+	return uid, gid, err
 }
 
 // Empty returns true if there are no id mappings