2 files changed, 127 insertions, 0 deletions
diff --git a/pkg/osutil/tar.go b/pkg/osutil/tar.go
new file mode 100644
index 000000000..32500e7e4
--- /dev/null
+++ b/pkg/osutil/tar.go
@@ -0,0 +1,67 @@
+// Copyright 2025 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package osutil
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func TarGzDirectory(dir string, writer io.Writer) error {
+	gzw := gzip.NewWriter(writer)
+	defer gzw.Close()
+	return tarDirectory(dir, gzw)
+}
+
+func tarDirectory(dir string, writer io.Writer) error {
+	tw := tar.NewWriter(writer)
+	defer tw.Close()
+
+	return filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
+		if err != nil || path == dir {
+			return err
+		}
+		typ := d.Type()
+		if !typ.IsDir() && !typ.IsRegular() {
+			// Only folders and regular files.
+			return nil
+		}
+		relPath, err := filepath.Rel(dir, path)
+		if err != nil {
+			return err
+		}
+		relPath = filepath.ToSlash(relPath)
+		info, err := d.Info()
+		if err != nil {
+			return err
+		}
+		header, err := tar.FileInfoHeader(info, "")
+		if err != nil {
+			return err
+		}
+		header.Name = relPath
+		if typ.IsDir() && !strings.HasSuffix(header.Name, "/") {
+			header.Name += "/"
+		}
+		if err := tw.WriteHeader(header); err != nil {
+			return err
+		}
+		if typ.IsDir() {
+			return nil
+		}
+		// Write the file content.
+		f, err := os.Open(path)
+		if err != nil {
+			return err
+		}
+		_, err = io.Copy(tw, f)
+		f.Close()
+		return err
+	})
+}
diff --git a/pkg/osutil/tar_test.go b/pkg/osutil/tar_test.go
new file mode 100644
index 000000000..a0e5a22bd
--- /dev/null
+++ b/pkg/osutil/tar_test.go
@@ -0,0 +1,60 @@
+// Copyright 2025 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package osutil
+
+import (
+	"archive/tar"
+	"bytes"
+	"io"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTarDirectory(t *testing.T) {
+	dir := t.TempDir()
+
+	items := map[string]string{
+		"file1.txt":     "first file content",
+		"dir/file2.txt": "second file content",
+		"empty.txt":     "",
+	}
+
+	for path, content := range items {
+		fullPath := filepath.Join(dir, path)
+		dirPath := filepath.Dir(fullPath)
+		if err := MkdirAll(dirPath); err != nil {
+			t.Fatalf("mkdir %q failed: %v", dirPath, err)
+		}
+		if err := WriteFile(fullPath, []byte(content)); err != nil {
+			t.Fatalf("write file failed: %v", err)
+		}
+	}
+
+	var buf bytes.Buffer
+	err := tarDirectory(dir, &buf)
+	assert.NoError(t, err)
+
+	tr := tar.NewReader(&buf)
+	found := make(map[string]string)
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Fatal(err)
+		}
+		if hdr.Typeflag == tar.TypeReg {
+			contentBytes, err := io.ReadAll(tr)
+			if err != nil {
+				t.Fatal(err)
+			}
+			found[hdr.Name] = string(contentBytes)
+		}
+	}
+
+	assert.Equal(t, items, found)
+}