From 51e6c252c495234fc4acc256d65fcb04888357a2 Mon Sep 17 00:00:00 2001
From: Colin Cross <ccross@android.com>
Date: Tue, 27 Feb 2018 16:00:00 -0800
Subject: [PATCH] Make memunreachable_binder_test suitable for VTS

Link statically against libmemunreachable to avoid runtime
dependency on libmemunreachable.so.
Provide a better error when run as non-root.
Rename the test to MemunreachableBinderTest.
Add comments explaining the test sequence.

Bug: 28275695
Test: memunreachable_binder_test
Change-Id: Iddfba636205b7ca3ad31a6ba2c4e85abadd32d0d
---
 libmemunreachable/Android.bp            |  6 +++---
 libmemunreachable/tests/Binder_test.cpp | 16 ++++++++++++++--
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/libmemunreachable/Android.bp b/libmemunreachable/Android.bp
index b428dd785..caca3774e 100644
--- a/libmemunreachable/Android.bp
+++ b/libmemunreachable/Android.bp
@@ -20,7 +20,7 @@ cc_defaults {
     },
 }
 
-cc_library_shared {
+cc_library {
     name: "libmemunreachable",
     defaults: ["libmemunreachable_defaults"],
     srcs: [
@@ -88,14 +88,14 @@ cc_test {
 cc_test {
     name: "memunreachable_binder_test",
     defaults: ["libmemunreachable_defaults"],
+    test_suites: ["vts"],
     srcs: [
         "tests/Binder_test.cpp",
-        "tests/MemUnreachable_test.cpp",
     ],
+    static_libs: ["libmemunreachable"],
     shared_libs: [
         "libbinder",
         "libhwbinder",
-        "libmemunreachable",
         "libutils",
     ],
 }
diff --git a/libmemunreachable/tests/Binder_test.cpp b/libmemunreachable/tests/Binder_test.cpp
index 6e85d5ab3..eaf7652d1 100644
--- a/libmemunreachable/tests/Binder_test.cpp
+++ b/libmemunreachable/tests/Binder_test.cpp
@@ -33,6 +33,9 @@ namespace android {
 
 static const String16 service_name("test.libmemunreachable_binder");
 
+// Provides a service that will hold a strong reference to any remote binder
+// object, so that the test can verify that a remote strong reference is
+// visible to libmemunreachable.
 class BinderService : public BBinder {
  public:
   BinderService() = default;
@@ -55,6 +58,8 @@ class BinderObject : public BBinder {
   ~BinderObject() = default;
 };
 
+// Forks a subprocess that registers a BinderService with the global binder
+// servicemanager.  Requires root permissions.
 class ServiceProcess {
  public:
   ServiceProcess() : child_(0) {}
@@ -97,6 +102,7 @@ class ServiceProcess {
       fprintf(stderr, "Failed to get service manager\n");
       return 1;
     }
+    // This step requires root permissions
     if (sm->addService(service_name, new BinderService()) != OK) {
       fprintf(stderr, "Failed to add test service\n");
       return 1;
@@ -110,12 +116,18 @@ class ServiceProcess {
   pid_t child_;
 };
 
-class BinderTest : public ::testing::Test {
+class MemunreachableBinderTest : public ::testing::Test {
  protected:
   ServiceProcess service_process_;
 };
 
-TEST_F(BinderTest, binder) {
+// Tests that a local binder object with a remote strong reference is visible
+// through the libmemunreachable BinderReferences interface, which uses the
+// getBinderKernelReferences method in libbinder.  Starts a BinderService
+// through ServiceProcess as a remote service to hold the strong reference.
+TEST_F(MemunreachableBinderTest, binder) {
+  ASSERT_EQ(static_cast<uid_t>(0), getuid()) << "This test must be run as root.";
+
   ServiceProcess service_process;
   ASSERT_TRUE(service_process.Run());