Initial commit on Forgejo

Fresh repository history for elektrine/magpie hosted at
https://git.elektrine.com/elektrine/magpie.

backup.go

@@ -0,0 +1,181 @@
+package main
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func BackupDir(src string, dst string) error {
+	out, err := os.OpenFile(dst, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0o600)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+	gz := gzip.NewWriter(out)
+	defer gz.Close()
+	tw := tar.NewWriter(gz)
+	defer tw.Close()
+	root, err := filepath.Abs(src)
+	if err != nil {
+		return err
+	}
+	return filepath.WalkDir(root, func(path string, entry os.DirEntry, err error) error {
+		if err != nil || entry.IsDir() {
+			return err
+		}
+		if entry.Type()&os.ModeSymlink != 0 {
+			return fmt.Errorf("refusing to back up symlink %q", path)
+		}
+		rel, err := filepath.Rel(root, path)
+		if err != nil {
+			return err
+		}
+		info, err := entry.Info()
+		if err != nil {
+			return err
+		}
+		header, err := tar.FileInfoHeader(info, "")
+		if err != nil {
+			return err
+		}
+		header.Name = filepath.ToSlash(rel)
+		if err := tw.WriteHeader(header); err != nil {
+			return err
+		}
+		file, err := os.Open(path)
+		if err != nil {
+			return err
+		}
+		fileInfo, statErr := file.Stat()
+		currentInfo, lstatErr := os.Lstat(path)
+		if statErr != nil || lstatErr != nil {
+			_ = file.Close()
+			if statErr != nil {
+				return statErr
+			}
+			return lstatErr
+		}
+		if currentInfo.Mode()&os.ModeSymlink != 0 || !os.SameFile(currentInfo, fileInfo) {
+			_ = file.Close()
+			return fmt.Errorf("refusing to back up replaced or symlinked file %q", path)
+		}
+		_, copyErr := io.Copy(tw, file)
+		closeErr := file.Close()
+		if copyErr != nil {
+			return copyErr
+		}
+		return closeErr
+	})
+}
+
+func RestoreDir(src string, dst string) error {
+	return RestoreDirWithLimit(src, dst, defaultMaxRestoreBytes)
+}
+
+func RestoreDirWithLimit(src string, dst string, maxBytes int64) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+	gz, err := gzip.NewReader(in)
+	if err != nil {
+		return err
+	}
+	defer gz.Close()
+	tr := tar.NewReader(gz)
+	root, err := filepath.Abs(dst)
+	if err != nil {
+		return err
+	}
+	if err := os.MkdirAll(root, 0o700); err != nil {
+		return err
+	}
+	var restoredBytes int64
+	for {
+		header, err := tr.Next()
+		if err == io.EOF {
+			return nil
+		}
+		if err != nil {
+			return err
+		}
+		if strings.Contains(header.Name, "..") || strings.HasPrefix(header.Name, "/") {
+			return fmt.Errorf("unsafe archive path %q", header.Name)
+		}
+		if header.Typeflag != tar.TypeReg && header.Typeflag != tar.TypeRegA && header.Typeflag != tar.TypeDir {
+			return fmt.Errorf("unsupported archive entry %q", header.Name)
+		}
+		if header.Size < 0 {
+			return fmt.Errorf("invalid archive size for %q", header.Name)
+		}
+		if header.Typeflag == tar.TypeReg || header.Typeflag == tar.TypeRegA {
+			restoredBytes += header.Size
+			if maxBytes > 0 && restoredBytes > maxBytes {
+				return fmt.Errorf("restore exceeds maximum size")
+			}
+		}
+		path := filepath.Join(root, filepath.FromSlash(header.Name))
+		if !strings.HasPrefix(path, root+string(os.PathSeparator)) && path != root {
+			return fmt.Errorf("unsafe archive path %q", header.Name)
+		}
+		if err := rejectSymlinkParents(root, path); err != nil {
+			return err
+		}
+		if header.FileInfo().IsDir() {
+			if err := os.MkdirAll(path, 0o700); err != nil {
+				return err
+			}
+			continue
+		}
+		if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
+			return err
+		}
+		if info, err := os.Lstat(path); err == nil && info.Mode()&os.ModeSymlink != 0 {
+			return fmt.Errorf("refusing to restore through symlink %q", header.Name)
+		}
+		out, err := os.OpenFile(path, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0o600)
+		if err != nil {
+			return err
+		}
+		_, copyErr := io.CopyN(out, tr, header.Size)
+		closeErr := out.Close()
+		if copyErr != nil {
+			return copyErr
+		}
+		if closeErr != nil {
+			return closeErr
+		}
+	}
+}
+
+func rejectSymlinkParents(root string, path string) error {
+	current := root
+	rel, err := filepath.Rel(root, filepath.Dir(path))
+	if err != nil {
+		return err
+	}
+	if rel == "." {
+		return nil
+	}
+	for _, part := range strings.Split(rel, string(os.PathSeparator)) {
+		current = filepath.Join(current, part)
+		info, err := os.Lstat(current)
+		if errors.Is(err, os.ErrNotExist) {
+			return nil
+		}
+		if err != nil {
+			return err
+		}
+		if info.Mode()&os.ModeSymlink != 0 {
+			return fmt.Errorf("refusing to restore through symlink parent %q", current)
+		}
+	}
+	return nil
+}