Support readonly rootfs contains colon

Fix: https://github.com/containers/podman/issues/11913

Signed-off-by: chenkang <kongchen28@gmail.com>

pkg/specgen/specgen_test.go

@@ -0,0 +1,25 @@
+package specgen
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewSpecGeneratorWithRootfs(t *testing.T) {
+	tests := []struct {
+		rootfs                string
+		expectedRootfsOverlay bool
+		expectedRootfs        string
+	}{
+		{"/root/a:b:O", true, "/root/a:b"},
+		{"/root/a:b/c:O", true, "/root/a:b/c"},
+		{"/root/a:b/c:", false, "/root/a:b/c:"},
+		{"/root/a/b", false, "/root/a/b"},
+	}
+	for _, args := range tests {
+		val := NewSpecGenerator(args.rootfs, true)
+		assert.Equal(t, val.RootfsOverlay, args.rootfs)
+		assert.Equal(t, val.Rootfs, args.rootfs)
+	}
+}