Add disable/get/set_hidden_api_enforcement_policy extensions

Add JVMTI extensions to control the hidden-api enforcement policy. The
new extensions
com.android.art.misc.{disable,get,set}_hidden_api_enforcement_policy
use the int representations defined by ApplicationInfo.java. Users of
these APIs should be sure to toggle the hidden-api state temporarily
as needed and should avoid turning it off for long periods in order to
ensure users can continue to find bugs.

Test: ./test.py --host
Bug: 175329755
Change-Id: I89848faf6cf53179b713c6ca9f19f1fe8062b739

1 files changed, 121 insertions, 0 deletions

diff --git a/test/2038-hiddenapi-jvmti-ext/hiddenapi_ext.cc b/test/2038-hiddenapi-jvmti-ext/hiddenapi_ext.cc
new file mode 100644
index 0000000000..c012b117ad
--- /dev/null
+++ b/test/2038-hiddenapi-jvmti-ext/hiddenapi_ext.cc
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2020 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 <queue>
+#include <vector>
+
+#include "jvmti.h"
+
+// Test infrastructure
+#include "jvmti_helper.h"
+#include "nativehelper/scoped_local_ref.h"
+#include "nativehelper/scoped_primitive_array.h"
+#include "test_env.h"
+
+namespace art {
+namespace Test2038HiddenApiExt {
+
+template <typename T>
+static void Dealloc(T* t) {
+  jvmti_env->Deallocate(reinterpret_cast<unsigned char*>(t));
+}
+
+template <typename T, typename... Rest>
+static void Dealloc(T* t, Rest... rs) {
+  Dealloc(t);
+  Dealloc(rs...);
+}
+
+static void DeallocParams(jvmtiParamInfo* params, jint n_params) {
+  for (jint i = 0; i < n_params; i++) {
+    Dealloc(params[i].name);
+  }
+}
+
+static constexpr std::string_view kDisablePolicyName =
+    "com.android.art.misc.disable_hidden_api_enforcement_policy";
+static constexpr std::string_view kGetPolicyName =
+    "com.android.art.misc.get_hidden_api_enforcement_policy";
+static constexpr std::string_view kSetPolicyName =
+    "com.android.art.misc.set_hidden_api_enforcement_policy";
+using GetPolicy = jvmtiError (*)(jvmtiEnv*, jint*);
+using SetPolicy = jvmtiError (*)(jvmtiEnv*, jint);
+using DisablePolicy = jvmtiError (*)(jvmtiEnv*);
+
+void* GetExtension(JNIEnv* env, const std::string_view& name) {
+  // Get the extensions.
+  jint n_ext = 0;
+  void* result = nullptr;
+  jvmtiExtensionFunctionInfo* infos = nullptr;
+  if (JvmtiErrorToException(env, jvmti_env, jvmti_env->GetExtensionFunctions(&n_ext, &infos))) {
+    return nullptr;
+  }
+  for (jint i = 0; i < n_ext; i++) {
+    jvmtiExtensionFunctionInfo* cur_info = &infos[i];
+    if (name == std::string_view(cur_info->id)) {
+      result = reinterpret_cast<void*>(cur_info->func);
+    }
+    // Cleanup the cur_info
+    DeallocParams(cur_info->params, cur_info->param_count);
+    Dealloc(cur_info->id, cur_info->short_description, cur_info->params, cur_info->errors);
+  }
+  // Cleanup the array.
+  Dealloc(infos);
+  if (result == nullptr) {
+    ScopedLocalRef<jclass> rt_exception(env, env->FindClass("java/lang/RuntimeException"));
+    env->ThrowNew(rt_exception.get(), "Unable to find policy extensions.");
+    return nullptr;
+  }
+  return result;
+}
+
+extern "C" JNIEXPORT jint JNICALL Java_Main_disablePolicy(JNIEnv* env, jclass) {
+  jint res;
+  GetPolicy get_policy = reinterpret_cast<GetPolicy>(GetExtension(env, kGetPolicyName));
+  if (get_policy == nullptr) {
+    return -1;
+  }
+  DisablePolicy disable_policy =
+      reinterpret_cast<DisablePolicy>(GetExtension(env, kDisablePolicyName));
+  if (disable_policy == nullptr) {
+    return -1;
+  }
+  if (JvmtiErrorToException(env, jvmti_env, get_policy(jvmti_env, &res))) {
+    return -1;
+  }
+  JvmtiErrorToException(env, jvmti_env, disable_policy(jvmti_env));
+  return res;
+}
+
+extern "C" JNIEXPORT jint JNICALL Java_Main_setPolicy(JNIEnv* env, jclass, jint pol) {
+  jint res;
+  GetPolicy get_policy = reinterpret_cast<GetPolicy>(GetExtension(env, kGetPolicyName));
+  if (get_policy == nullptr) {
+    return -1;
+  }
+  SetPolicy set_policy = reinterpret_cast<SetPolicy>(GetExtension(env, kSetPolicyName));
+  if (set_policy == nullptr) {
+    return -1;
+  }
+  if (JvmtiErrorToException(env, jvmti_env, get_policy(jvmti_env, &res))) {
+    return -1;
+  }
+  JvmtiErrorToException(env, jvmti_env, set_policy(jvmti_env, pol));
+  return res;
+}
+
+}  // namespace Test2038HiddenApiExt
+}  // namespace art