cmd/hi: fixes and qol (#2649)

cmd/hi/tar_utils.go

@@ -0,0 +1,101 @@
+package main
+
+import (
+	"archive/tar"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+var (
+	// ErrFileNotFoundInTar indicates a file was not found in the tar archive.
+	ErrFileNotFoundInTar = errors.New("file not found in tar")
+)
+
+// extractFileFromTar extracts a single file from a tar reader.
+func extractFileFromTar(tarReader io.Reader, fileName, outputPath string) error {
+	tr := tar.NewReader(tarReader)
+
+	for {
+		header, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return fmt.Errorf("failed to read tar header: %w", err)
+		}
+
+		// Check if this is the file we're looking for
+		if filepath.Base(header.Name) == fileName {
+			if header.Typeflag == tar.TypeReg {
+				// Create the output file
+				outFile, err := os.Create(outputPath)
+				if err != nil {
+					return fmt.Errorf("failed to create output file: %w", err)
+				}
+				defer outFile.Close()
+
+				// Copy file contents
+				if _, err := io.Copy(outFile, tr); err != nil {
+					return fmt.Errorf("failed to copy file contents: %w", err)
+				}
+				return nil
+			}
+		}
+	}
+
+	return fmt.Errorf("%w: %s", ErrFileNotFoundInTar, fileName)
+}
+
+// extractDirectoryFromTar extracts all files from a tar reader to a target directory.
+func extractDirectoryFromTar(tarReader io.Reader, targetDir string) error {
+	tr := tar.NewReader(tarReader)
+
+	for {
+		header, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return fmt.Errorf("failed to read tar header: %w", err)
+		}
+
+		// Clean the path to prevent directory traversal
+		cleanName := filepath.Clean(header.Name)
+		if strings.Contains(cleanName, "..") {
+			continue // Skip potentially dangerous paths
+		}
+
+		targetPath := filepath.Join(targetDir, filepath.Base(cleanName))
+
+		switch header.Typeflag {
+		case tar.TypeDir:
+			// Create directory
+			if err := os.MkdirAll(targetPath, os.FileMode(header.Mode)); err != nil {
+				return fmt.Errorf("failed to create directory %s: %w", targetPath, err)
+			}
+		case tar.TypeReg:
+			// Create file
+			outFile, err := os.Create(targetPath)
+			if err != nil {
+				return fmt.Errorf("failed to create file %s: %w", targetPath, err)
+			}
+
+			if _, err := io.Copy(outFile, tr); err != nil {
+				outFile.Close()
+				return fmt.Errorf("failed to copy file contents: %w", err)
+			}
+			outFile.Close()
+
+			// Set file permissions
+			if err := os.Chmod(targetPath, os.FileMode(header.Mode)); err != nil {
+				return fmt.Errorf("failed to set file permissions: %w", err)
+			}
+		}
+	}
+
+	return nil
+}