restic/internal/dump/tar.go

124 lines
2.8 KiB
Go

package dump
import (
"archive/tar"
"context"
"io"
"os"
"path/filepath"
"strings"
"github.com/restic/restic/internal/bloblru"
"github.com/restic/restic/internal/errors"
"github.com/restic/restic/internal/restic"
)
type tarDumper struct {
cache *bloblru.Cache
w *tar.Writer
}
// Statically ensure that tarDumper implements dumper.
var _ dumper = &tarDumper{}
// WriteTar will write the contents of the given tree, encoded as a tar to the given destination.
func WriteTar(ctx context.Context, repo restic.Repository, tree *restic.Tree, rootPath string, dst io.Writer) error {
dmp := &tarDumper{
cache: NewCache(),
w: tar.NewWriter(dst),
}
return writeDump(ctx, repo, tree, rootPath, dmp)
}
func (dmp *tarDumper) Close() error {
return dmp.w.Close()
}
// copied from archive/tar.FileInfoHeader
const (
// Mode constants from the USTAR spec:
// See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13_06
cISUID = 0o4000 // Set uid
cISGID = 0o2000 // Set gid
cISVTX = 0o1000 // Save text (sticky bit)
)
func (dmp *tarDumper) dumpNode(ctx context.Context, node *restic.Node, repo restic.Repository) error {
relPath, err := filepath.Rel("/", node.Path)
if err != nil {
return err
}
header := &tar.Header{
Name: filepath.ToSlash(relPath),
Size: int64(node.Size),
Mode: int64(node.Mode.Perm()), // cIS* constants are added later
Uid: int(node.UID),
Gid: int(node.GID),
Uname: node.User,
Gname: node.Group,
ModTime: node.ModTime,
AccessTime: node.AccessTime,
ChangeTime: node.ChangeTime,
PAXRecords: parseXattrs(node.ExtendedAttributes),
}
// adapted from archive/tar.FileInfoHeader
if node.Mode&os.ModeSetuid != 0 {
header.Mode |= cISUID
}
if node.Mode&os.ModeSetgid != 0 {
header.Mode |= cISGID
}
if node.Mode&os.ModeSticky != 0 {
header.Mode |= cISVTX
}
if IsFile(node) {
header.Typeflag = tar.TypeReg
}
if IsLink(node) {
header.Typeflag = tar.TypeSymlink
header.Linkname = node.LinkTarget
}
if IsDir(node) {
header.Typeflag = tar.TypeDir
header.Name += "/"
}
err = dmp.w.WriteHeader(header)
if err != nil {
return errors.Wrap(err, "TarHeader")
}
return WriteNodeData(ctx, dmp.w, repo, node, dmp.cache)
}
func parseXattrs(xattrs []restic.ExtendedAttribute) map[string]string {
tmpMap := make(map[string]string)
for _, attr := range xattrs {
attrString := string(attr.Value)
if strings.HasPrefix(attr.Name, "system.posix_acl_") {
na := acl{}
na.decode(attr.Value)
if na.String() != "" {
if strings.Contains(attr.Name, "system.posix_acl_access") {
tmpMap["SCHILY.acl.access"] = na.String()
} else if strings.Contains(attr.Name, "system.posix_acl_default") {
tmpMap["SCHILY.acl.default"] = na.String()
}
}
} else {
tmpMap["SCHILY.xattr."+attr.Name] = attrString
}
}
return tmpMap
}