libdm: Add unit tests for dm-linear.

Bug: 110035986
Test: libdm_test gtest
Change-Id: I83fb978931aa36b83880c4d44745cc45ee516fc4

1 files changed, 52 insertions, 0 deletions

diff --git a/fs_mgr/libdm/test_util.cpp b/fs_mgr/libdm/test_util.cpp
new file mode 100644
index 000000000..307251cda
--- /dev/null
+++ b/fs_mgr/libdm/test_util.cpp
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <fcntl.h>
+#include <linux/memfd.h>
+#include <stdio.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "test_util.h"
+
+namespace android {
+namespace dm {
+
+using unique_fd = android::base::unique_fd;
+
+// Create a temporary in-memory file. If size is non-zero, the file will be
+// created with a fixed size.
+unique_fd CreateTempFile(const std::string& name, size_t size) {
+    unique_fd fd(syscall(__NR_memfd_create, name.c_str(), MFD_ALLOW_SEALING));
+    if (fd < 0) {
+        return {};
+    }
+    if (size) {
+        if (ftruncate(fd, size) < 0) {
+            perror("ftruncate");
+            return {};
+        }
+        if (fcntl(fd, F_ADD_SEALS, F_SEAL_GROW | F_SEAL_SHRINK) < 0) {
+            perror("fcntl");
+            return {};
+        }
+    }
+    return fd;
+}
+
+}  // namespace dm
+}  // namespace android