talos

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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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package archiver
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import (
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	"archive/tar"
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	"context"
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	"errors"
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	"fmt"
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	"io"
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	"os"
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	"path/filepath"
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	"github.com/siderolabs/talos/pkg/safepath"
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)
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// Untar extracts .tar archive from r into filesystem under rootPath.
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//
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//nolint:gocyclo
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func Untar(ctx context.Context, r io.Reader, rootPath string) error {
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	tr := tar.NewReader(r)
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	for {
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		select {
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		case <-ctx.Done():
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			return ctx.Err()
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		default:
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		}
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		hdr, err := tr.Next()
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		if err != nil {
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			if err == io.EOF {
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				break
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			}
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			return fmt.Errorf("error reading tar header: %s", err)
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		}
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		hdrPath := safepath.CleanPath(hdr.Name)
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		if hdrPath == "" {
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			return errors.New("empty tar header path")
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		}
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		path := filepath.Join(rootPath, hdrPath)
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		switch hdr.Typeflag {
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		case tar.TypeDir:
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			mode := hdr.FileInfo().Mode()
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			mode |= 0o700 // make rwx for the owner
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			if err = os.Mkdir(path, mode); err != nil {
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				return fmt.Errorf("error creating directory %q mode %s: %w", path, mode, err)
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			}
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			if err = os.Chmod(path, mode); err != nil {
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				return fmt.Errorf("error updating mode %s for %q: %w", mode, path, err)
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			}
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		case tar.TypeSymlink:
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			if err = os.Symlink(hdr.Linkname, path); err != nil {
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				return fmt.Errorf("error creating symlink %q -> %q: %w", path, hdr.Linkname, err)
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			}
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		default:
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			mode := hdr.FileInfo().Mode()
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			fp, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_EXCL, mode)
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			if err != nil {
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				return fmt.Errorf("error creating file %q mode %s: %w", path, mode, err)
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			}
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			_, err = io.Copy(fp, tr)
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			if err != nil {
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				return fmt.Errorf("error copying data to %q: %w", path, err)
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			}
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			if err = fp.Close(); err != nil {
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				return fmt.Errorf("error closing %q: %w", path, err)
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			}
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			if err = os.Chmod(path, mode); err != nil {
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				return fmt.Errorf("error updating mode %s for %q: %w", mode, path, err)
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			}
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		}
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	}
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	return nil
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}
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