3 files changed, 84 insertions, 0 deletions
diff --git a/test/util/BUILD b/test/util/BUILD
index 25ed9c944..5d2a9cc2c 100644
--- a/test/util/BUILD
+++ b/test/util/BUILD
@@ -324,3 +324,14 @@ cc_library(
         ":test_util",
     ],
 )
+
+cc_library(
+    name = "uid_util",
+    testonly = 1,
+    srcs = ["uid_util.cc"],
+    hdrs = ["uid_util.h"],
+    deps = [
+        ":posix_error",
+        ":save_util",
+    ],
+)
diff --git a/test/util/uid_util.cc b/test/util/uid_util.cc
new file mode 100644
index 000000000..b131b4b99
--- /dev/null
+++ b/test/util/uid_util.cc
@@ -0,0 +1,44 @@
+// Copyright 2018 The gVisor Authors.
+//
+// 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 "test/util/posix_error.h"
+#include "test/util/save_util.h"
+
+namespace gvisor {
+namespace testing {
+
+PosixErrorOr<bool> IsRoot() {
+  uid_t ruid, euid, suid;
+  int rc = getresuid(&ruid, &euid, &suid);
+  MaybeSave();
+  if (rc < 0) {
+    return PosixError(errno, "getresuid");
+  }
+  if (ruid != 0 || euid != 0 || suid != 0) {
+    return false;
+  }
+  gid_t rgid, egid, sgid;
+  rc = getresgid(&rgid, &egid, &sgid);
+  MaybeSave();
+  if (rc < 0) {
+    return PosixError(errno, "getresgid");
+  }
+  if (rgid != 0 || egid != 0 || sgid != 0) {
+    return false;
+  }
+  return true;
+}
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/util/uid_util.h b/test/util/uid_util.h
new file mode 100644
index 000000000..2cd387fb0
--- /dev/null
+++ b/test/util/uid_util.h
@@ -0,0 +1,29 @@
+// Copyright 2018 The gVisor Authors.
+//
+// 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.
+
+#ifndef GVISOR_TEST_SYSCALLS_UID_UTIL_H_
+#define GVISOR_TEST_SYSCALLS_UID_UTIL_H_
+
+#include "test/util/posix_error.h"
+
+namespace gvisor {
+namespace testing {
+
+// Returns true if the caller's real/effective/saved user/group IDs are all 0.
+PosixErrorOr<bool> IsRoot();
+
+}  // namespace testing
+}  // namespace gvisor
+
+#endif  // GVISOR_TEST_SYSCALLS_UID_UTIL_H_