Cli updater (#3382)

cli/update/tar.go

@@ -0,0 +1,60 @@
+package update
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+)
+
+const tarDirectoryMode fs.FileMode = 0x755
+
+func Untar(dst string, r io.Reader) error {
+	gzr, err := gzip.NewReader(r)
+	if err != nil {
+		return err
+	}
+	defer gzr.Close()
+
+	tr := tar.NewReader(gzr)
+
+	for {
+		header, err := tr.Next()
+
+		switch {
+		case err == io.EOF:
+			return nil
+
+		case err != nil:
+			return err
+
+		case header == nil:
+			continue
+		}
+
+		target := filepath.Join(dst, header.Name)
+
+		switch header.Typeflag {
+		case tar.TypeDir:
+			if _, err := os.Stat(target); err != nil {
+				if err := os.MkdirAll(target, tarDirectoryMode); err != nil {
+					return err
+				}
+			}
+
+		case tar.TypeReg:
+			f, err := os.OpenFile(target, os.O_CREATE|os.O_RDWR, os.FileMode(header.Mode))
+			if err != nil {
+				return err
+			}
+
+			if _, err := io.Copy(f, tr); err != nil {
+				return err
+			}
+
+			f.Close()
+		}
+	}
+}