1 files changed, 50 insertions, 0 deletions
diff --git a/test/syscalls/linux/unshare.cc b/test/syscalls/linux/unshare.cc
new file mode 100644
index 000000000..9dd6ec4b6
--- /dev/null
+++ b/test/syscalls/linux/unshare.cc
@@ -0,0 +1,50 @@
+// Copyright 2018 Google LLC
+//
+// 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 <errno.h>
+#include <sched.h>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/synchronization/mutex.h"
+#include "test/util/test_util.h"
+#include "test/util/thread_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+TEST(UnshareTest, AllowsZeroFlags) {
+  ASSERT_THAT(unshare(0), SyscallSucceeds());
+}
+
+TEST(UnshareTest, ThreadFlagFailsIfMultithreaded) {
+  absl::Mutex mu;
+  bool finished = false;
+  ScopedThread t([&] {
+    mu.Lock();
+    mu.Await(absl::Condition(&finished));
+    mu.Unlock();
+  });
+  ASSERT_THAT(unshare(CLONE_THREAD), SyscallFailsWithErrno(EINVAL));
+  mu.Lock();
+  finished = true;
+  mu.Unlock();
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor