Refactor backup restauration

Author: aledbf

components/content-service/pkg/archive/tar.go

@@ -5,19 +5,13 @@
 package archive
 
 import (
-	"archive/tar"
 	"context"
 	"io"
-	"os"
-	"os/exec"
-	"path"
-	"sort"
-	"syscall"
 	"time"
 
-	"github.com/moby/moby/pkg/system"
+	"github.com/containers/storage/pkg/archive"
+	"github.com/containers/storage/pkg/idtools"
 	"github.com/opentracing/opentracing-go"
-	"golang.org/x/xerrors"
 
 	"github.com/gitpod-io/gitpod/common-go/log"
 	"github.com/gitpod-io/gitpod/common-go/tracing"
@@ -66,141 +60,29 @@ func ExtractTarbal(ctx context.Context, src io.Reader, dst string, opts ...TarOp
 		opt(&cfg)
 	}
 
-	pr, pw := io.Pipe()
-	src = io.TeeReader(src, pw)
-	tarReader := tar.NewReader(pr)
-
-	type Info struct {
-		UID, GID  int
-		IsSymlink bool
-		Xattrs    map[string]string
-	}
-
-	finished := make(chan bool)
-	m := make(map[string]Info)
-
-	go func() {
-		defer close(finished)
-		for {
-			hdr, err := tarReader.Next()
-			if err == io.EOF {
-				finished <- true
-				return
-			}
-
-			if err != nil {
-				log.WithError(err).Error("error reading tar")
-				return
-			}
-
-			m[hdr.Name] = Info{
-				UID:       hdr.Uid,
-				GID:       hdr.Gid,
-				IsSymlink: (hdr.Linkname != ""),
-				//nolint:staticcheck
-				Xattrs: hdr.Xattrs,
-			}
+	uidMaps := make([]idtools.IDMap, len(cfg.UIDMaps))
+	for i, m := range cfg.UIDMaps {
+		uidMaps[i] = idtools.IDMap{
+			ContainerID: m.ContainerID,
+			HostID:      m.HostID,
+			Size:        m.Size,
 		}
-	}()
-
-	// Be explicit about the tar flags. We want to restore the exact content without changes
-	tarcmd := exec.Command(
-		"tar",
-		"--extract",
-		"--preserve-permissions",
-		"--xattrs", "--xattrs-include=security.capability",
-	)
-	tarcmd.Dir = dst
-	tarcmd.Stdin = src
-
-	var msg []byte
-	msg, err = tarcmd.CombinedOutput()
-	if err != nil {
-		return xerrors.Errorf("tar %s: %s", dst, err.Error()+";"+string(msg))
 	}
-
-	log.WithField("log", string(msg)).Debug("decompressing tar stream log")
-
-	<-finished
-
-	// lets create a sorted list of pathes and chown depth first.
-	paths := make([]string, 0, len(m))
-	for path := range m {
-		paths = append(paths, path)
-	}
-	sort.Sort(sort.Reverse(sort.StringSlice(paths)))
-
-	// We need to remap the UID and GID between the host and the container to avoid permission issues.
-	for _, p := range paths {
-		v := m[p]
-		uid := toHostID(v.UID, cfg.UIDMaps)
-		gid := toHostID(v.GID, cfg.GIDMaps)
-
-		if v.IsSymlink {
-			continue
-		}
-
-		err = remapFile(path.Join(dst, p), uid, gid, v.Xattrs)
-		if err != nil {
-			log.WithError(err).WithField("uid", uid).WithField("gid", gid).WithField("path", p).Warn("cannot chown")
+	gidMaps := make([]idtools.IDMap, len(cfg.GIDMaps))
+	for i, m := range cfg.GIDMaps {
+		gidMaps[i] = idtools.IDMap{
+			ContainerID: m.ContainerID,
+			HostID:      m.HostID,
+			Size:        m.Size,
 		}
 	}
 
-	log.WithField("duration", time.Since(start).Milliseconds()).Debug("untar complete")
-	return nil
-}
+	err = archive.Untar(src, dst, &archive.TarOptions{
+		UIDMaps:     uidMaps,
+		GIDMaps:     gidMaps,
+		Compression: archive.Uncompressed,
+	})
 
-func toHostID(containerID int, idMap []IDMapping) int {
-	for _, m := range idMap {
-		if (containerID >= m.ContainerID) && (containerID <= (m.ContainerID + m.Size - 1)) {
-			hostID := m.HostID + (containerID - m.ContainerID)
-			return hostID
-		}
-	}
-	return containerID
-}
-
-// remapFile changes the UID and GID of a file preserving existing file mode bits.
-func remapFile(name string, uid, gid int, xattrs map[string]string) error {
-	// current info of the file before any change
-	fileInfo, err := os.Stat(name)
-	if err != nil {
-		return err
-	}
-
-	// nothing to do for symlinks
-	if fileInfo.Mode()&os.ModeSymlink == os.ModeSymlink {
-		return nil
-	}
-
-	// changing UID or GID can break files with suid/sgid
-	err = os.Lchown(name, uid, gid)
-	if err != nil {
-		return err
-	}
-
-	// restore original permissions
-	err = os.Chmod(name, fileInfo.Mode())
-	if err != nil {
-		return err
-	}
-
-	for key, value := range xattrs {
-		if err := system.Lsetxattr(name, key, []byte(value), 0); err != nil {
-			log.WithField("name", key).WithField("value", value).WithField("file", name).WithError(err).Error("restoring extended attributes")
-			if err == syscall.ENOTSUP || err == syscall.EPERM {
-				continue
-			}
-
-			return err
-		}
-	}
-
-	// restore file times
-	fileTime := fileInfo.Sys().(*syscall.Stat_t)
-	return os.Chtimes(name, timespecToTime(fileTime.Atim), timespecToTime(fileTime.Mtim))
-}
-
-func timespecToTime(ts syscall.Timespec) time.Time {
-	return time.Unix(int64(ts.Sec), int64(ts.Nsec))
+	log.WithField("duration", time.Since(start).Milliseconds()).Debug("untar complete")
+	return
 }