ART: Add JNI API

Add support for GetJNIFunctionTable and SetJNIFunctionTable. Add
tests.

Bug: 34343708
Test: m test-art-host-run-test-928-jni-table
Change-Id: Ib9fafbac2781c570aa6eacf5242afbbf6c3ee7a9
diff --git a/runtime/openjdkjvmti/Android.bp b/runtime/openjdkjvmti/Android.bp
index 081c429..d5c6520 100644
--- a/runtime/openjdkjvmti/Android.bp
+++ b/runtime/openjdkjvmti/Android.bp
@@ -23,6 +23,7 @@
            "ti_class.cc",
            "ti_field.cc",
            "ti_heap.cc",
+           "ti_jni.cc",
            "ti_method.cc",
            "ti_monitor.cc",
            "ti_object.cc",
diff --git a/runtime/openjdkjvmti/OpenjdkJvmTi.cc b/runtime/openjdkjvmti/OpenjdkJvmTi.cc
index ab4a48b..f5020ff 100644
--- a/runtime/openjdkjvmti/OpenjdkJvmTi.cc
+++ b/runtime/openjdkjvmti/OpenjdkJvmTi.cc
@@ -51,6 +51,7 @@
 #include "ti_class.h"
 #include "ti_field.h"
 #include "ti_heap.h"
+#include "ti_jni.h"
 #include "ti_method.h"
 #include "ti_monitor.h"
 #include "ti_object.h"
@@ -802,11 +803,11 @@
   }
 
   static jvmtiError SetJNIFunctionTable(jvmtiEnv* env, const jniNativeInterface* function_table) {
-    return ERR(NOT_IMPLEMENTED);
+    return JNIUtil::SetJNIFunctionTable(env, function_table);
   }
 
   static jvmtiError GetJNIFunctionTable(jvmtiEnv* env, jniNativeInterface** function_table) {
-    return ERR(NOT_IMPLEMENTED);
+    return JNIUtil::GetJNIFunctionTable(env, function_table);
   }
 
   // TODO: This will require locking, so that an agent can't remove callbacks when we're dispatching
diff --git a/runtime/openjdkjvmti/ti_jni.cc b/runtime/openjdkjvmti/ti_jni.cc
new file mode 100644
index 0000000..88f0395
--- /dev/null
+++ b/runtime/openjdkjvmti/ti_jni.cc
@@ -0,0 +1,91 @@
+/* Copyright (C) 2017 The Android Open Source Project
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This file implements interfaces from the file jvmti.h. This implementation
+ * is licensed under the same terms as the file jvmti.h.  The
+ * copyright and license information for the file jvmti.h follows.
+ *
+ * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include "ti_jni.h"
+
+#include "jni.h"
+
+#include "art_jvmti.h"
+#include "base/mutex.h"
+#include "java_vm_ext.h"
+#include "jni_env_ext.h"
+#include "runtime.h"
+#include "thread-inl.h"
+
+namespace openjdkjvmti {
+
+jvmtiError JNIUtil::SetJNIFunctionTable(jvmtiEnv* env ATTRIBUTE_UNUSED,
+                                        const jniNativeInterface* function_table) {
+  // While we supporting setting null (which will reset the table), the spec says no.
+  if (function_table == nullptr) {
+    return ERR(NULL_POINTER);
+  }
+
+  art::JNIEnvExt::SetTableOverride(function_table);
+  return ERR(NONE);
+}
+
+jvmtiError JNIUtil::GetJNIFunctionTable(jvmtiEnv* env, jniNativeInterface** function_table) {
+  if (function_table == nullptr) {
+    return ERR(NULL_POINTER);
+  }
+
+  // We use the generic JNIEnvExt::GetFunctionTable instead of querying a specific JNIEnv, as
+  // this has to work in the start phase.
+
+  // Figure out which table is current. Conservatively assume check-jni is off.
+  bool check_jni = false;
+  art::Runtime* runtime = art::Runtime::Current();
+  if (runtime != nullptr && runtime->GetJavaVM() != nullptr) {
+    check_jni = runtime->GetJavaVM()->IsCheckJniEnabled();
+  }
+
+  // Get that table.
+  const JNINativeInterface* current_table;
+  {
+    art::MutexLock mu(art::Thread::Current(), *art::Locks::jni_function_table_lock_);
+    current_table = art::JNIEnvExt::GetFunctionTable(check_jni);
+  }
+
+  // Allocate memory and copy the table.
+  unsigned char* data;
+  jvmtiError data_result = env->Allocate(sizeof(JNINativeInterface), &data);
+  if (data_result != ERR(NONE)) {
+    return data_result;
+  }
+  memcpy(data, current_table, sizeof(JNINativeInterface));
+
+  *function_table = reinterpret_cast<JNINativeInterface*>(data);
+
+  return ERR(NONE);
+}
+
+}  // namespace openjdkjvmti
diff --git a/runtime/openjdkjvmti/ti_jni.h b/runtime/openjdkjvmti/ti_jni.h
new file mode 100644
index 0000000..906aab0
--- /dev/null
+++ b/runtime/openjdkjvmti/ti_jni.h
@@ -0,0 +1,58 @@
+/* Copyright (C) 2017 The Android Open Source Project
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This file implements interfaces from the file jvmti.h. This implementation
+ * is licensed under the same terms as the file jvmti.h.  The
+ * copyright and license information for the file jvmti.h follows.
+ *
+ * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#ifndef ART_RUNTIME_OPENJDKJVMTI_TI_JNI_H_
+#define ART_RUNTIME_OPENJDKJVMTI_TI_JNI_H_
+
+#include "jni.h"
+#include "jvmti.h"
+
+namespace openjdkjvmti {
+
+// Note: Currently, JNI function table changes are sensitive to the order of operations wrt/
+//       CheckJNI. If an agent sets the function table, and a program than late-enables CheckJNI,
+//       CheckJNI will not be working (as the agent will forward to the non-CheckJNI table).
+//
+//       This behavior results from our usage of the function table to avoid a check of the
+//       CheckJNI flag. A future implementation may install on loading of this plugin an
+//       intermediate function table that explicitly checks the flag, so that switching CheckJNI
+//       is transparently handled.
+
+class JNIUtil {
+ public:
+  static jvmtiError SetJNIFunctionTable(jvmtiEnv* env, const jniNativeInterface* function_table);
+
+  static jvmtiError GetJNIFunctionTable(jvmtiEnv* env, jniNativeInterface** function_table);
+};
+
+}  // namespace openjdkjvmti
+
+#endif  // ART_RUNTIME_OPENJDKJVMTI_TI_JNI_H_
diff --git a/test/928-jni-table/build b/test/928-jni-table/build
new file mode 100755
index 0000000..898e2e5
--- /dev/null
+++ b/test/928-jni-table/build
@@ -0,0 +1,17 @@
+#!/bin/bash
+#
+# Copyright 2016 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.
+
+./default-build "$@" --experimental agents
diff --git a/test/928-jni-table/expected.txt b/test/928-jni-table/expected.txt
new file mode 100644
index 0000000..a965a70
--- /dev/null
+++ b/test/928-jni-table/expected.txt
@@ -0,0 +1 @@
+Done
diff --git a/test/928-jni-table/info.txt b/test/928-jni-table/info.txt
new file mode 100644
index 0000000..875a5f6
--- /dev/null
+++ b/test/928-jni-table/info.txt
@@ -0,0 +1 @@
+Tests basic functions in the jvmti plugin.
diff --git a/test/928-jni-table/jni_table.cc b/test/928-jni-table/jni_table.cc
new file mode 100644
index 0000000..5123d3a
--- /dev/null
+++ b/test/928-jni-table/jni_table.cc
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2013 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 <stdio.h>
+
+#include "jni.h"
+#include "openjdkjvmti/jvmti.h"
+
+#include "base/logging.h"
+#include "base/macros.h"
+
+#include "ti-agent/common_helper.h"
+#include "ti-agent/common_load.h"
+
+namespace art {
+namespace Test927JNITable {
+
+// This test is equivalent to the jni_internal_test JNIEnvExtTableOverride.
+
+static size_t gGlobalRefCount = 0;
+static JNINativeInterface* gOriginalEnv = nullptr;
+
+static jobject CountNewGlobalRef(JNIEnv* env, jobject o) {
+  ++gGlobalRefCount;
+  return gOriginalEnv->NewGlobalRef(env, o);
+}
+
+extern "C" JNIEXPORT void JNICALL Java_Main_doJNITableTest(
+    JNIEnv* env, jclass klass) {
+  // Get the current table, as the delegate.
+  jvmtiError getorig_result = jvmti_env->GetJNIFunctionTable(&gOriginalEnv);
+  if (JvmtiErrorToException(env, getorig_result)) {
+    return;
+  }
+
+  // Get the current table, as the override we'll install.
+  JNINativeInterface* env_override;
+  jvmtiError getoverride_result = jvmti_env->GetJNIFunctionTable(&env_override);
+  if (JvmtiErrorToException(env, getoverride_result)) {
+    return;
+  }
+
+  env_override->NewGlobalRef = CountNewGlobalRef;
+  gGlobalRefCount = 0;
+
+  // Install the override.
+  jvmtiError setoverride_result = jvmti_env->SetJNIFunctionTable(env_override);
+  if (JvmtiErrorToException(env, setoverride_result)) {
+    return;
+  }
+
+  jobject global = env->NewGlobalRef(klass);
+  CHECK_EQ(1u, gGlobalRefCount);
+  env->DeleteGlobalRef(global);
+
+  // Install the "original." There is no real reset.
+  jvmtiError setoverride2_result = jvmti_env->SetJNIFunctionTable(gOriginalEnv);
+  if (JvmtiErrorToException(env, setoverride2_result)) {
+    return;
+  }
+
+  jobject global2 = env->NewGlobalRef(klass);
+  CHECK_EQ(1u, gGlobalRefCount);
+  env->DeleteGlobalRef(global2);
+
+  // Try to install null. Should return NULL_POINTER error.
+  jvmtiError setoverride3_result = jvmti_env->SetJNIFunctionTable(nullptr);
+  if (setoverride3_result != JVMTI_ERROR_NULL_POINTER) {
+    LOG(FATAL) << "Didn't receive NULL_POINTER";
+  }
+
+  jvmti_env->Deallocate(reinterpret_cast<unsigned char*>(env_override));
+}
+
+}  // namespace Test927JNITable
+}  // namespace art
diff --git a/test/928-jni-table/run b/test/928-jni-table/run
new file mode 100755
index 0000000..4379349
--- /dev/null
+++ b/test/928-jni-table/run
@@ -0,0 +1,19 @@
+#!/bin/bash
+#
+# Copyright 2016 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.
+
+./default-run "$@" --experimental agents \
+                   --experimental runtime-plugins \
+                   --jvmti
diff --git a/test/928-jni-table/src/Main.java b/test/928-jni-table/src/Main.java
new file mode 100644
index 0000000..b0baea1
--- /dev/null
+++ b/test/928-jni-table/src/Main.java
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+public class Main {
+  public static void main(String[] args) throws Exception {
+    System.loadLibrary(args[1]);
+
+    doJNITableTest();
+
+    System.out.println("Done");
+  }
+
+  public static native void doJNITableTest();
+}
diff --git a/test/Android.bp b/test/Android.bp
index a1b283d..965d07a 100644
--- a/test/Android.bp
+++ b/test/Android.bp
@@ -267,6 +267,7 @@
         "924-threads/threads.cc",
         "925-threadgroups/threadgroups.cc",
         "927-timers/timers.cc",
+        "928-jni-table/jni_table.cc",
         "929-search/search.cc",
     ],
     shared_libs: [
diff --git a/test/Android.run-test.mk b/test/Android.run-test.mk
index 668d669..b1a0c918 100644
--- a/test/Android.run-test.mk
+++ b/test/Android.run-test.mk
@@ -306,6 +306,7 @@
   925-threadgroups \
   926-multi-obsolescence \
   927-timers \
+  928-jni-table \
   929-search \
 
 ifneq (,$(filter target,$(TARGET_TYPES)))