Add JNI Invocation API to libnativehelper

Change-Id: I15870937ad7bfa4757e21f83acbbb6a7826a0b0b

1 files changed, 120 insertions, 0 deletions

diff --git a/JniInvocation.cpp b/JniInvocation.cpp
new file mode 100644
index 0000000..08277f0
--- /dev/null
+++ b/JniInvocation.cpp
@@ -0,0 +1,120 @@
+/*
+ * 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 "JniInvocation.h"
+
+#include <dlfcn.h>
+#include <stdlib.h>
+
+#include <cstddef>
+
+#define LOG_TAG "JniInvocation"
+#include "cutils/log.h"
+
+#ifdef HAVE_ANDROID_OS
+#include "cutils/properties.h"
+#endif
+
+JniInvocation* JniInvocation::jni_invocation_ = NULL;
+
+JniInvocation::JniInvocation() :
+    handle_(NULL),
+    JNI_GetDefaultJavaVMInitArgs_(NULL),
+    JNI_CreateJavaVM_(NULL),
+    JNI_GetCreatedJavaVMs_(NULL) {
+
+  LOG_ALWAYS_FATAL_IF(jni_invocation_ != NULL, "JniInvocation instance already initialized");
+  jni_invocation_ = this;
+}
+
+JniInvocation::~JniInvocation() {
+  jni_invocation_ = NULL;
+  if (handle_ != NULL) {
+    dlclose(handle_);
+  }
+}
+
+bool JniInvocation::Init(const char* library) {
+#ifdef HAVE_ANDROID_OS
+  char default_library[PROPERTY_VALUE_MAX];
+  property_get("dalvik.vm.lib", default_library, "libdvm.so");
+#else
+  const char* default_library = "libdvm.so";
+#endif
+  if (library == NULL) {
+    library = default_library;
+  }
+
+  handle_ = dlopen(library, RTLD_NOW);
+  if (handle_ == NULL) {
+    ALOGE("Failed to dlopen %s: %s", library, dlerror());
+    return false;
+  }
+  if (!FindSymbol(reinterpret_cast<void**>(&JNI_GetDefaultJavaVMInitArgs_),
+                  "JNI_GetDefaultJavaVMInitArgs")) {
+    return false;
+  }
+  if (!FindSymbol(reinterpret_cast<void**>(&JNI_CreateJavaVM_),
+                  "JNI_CreateJavaVM")) {
+    return false;
+  }
+  if (!FindSymbol(reinterpret_cast<void**>(&JNI_GetCreatedJavaVMs_),
+                  "JNI_GetCreatedJavaVMs")) {
+    return false;
+  }
+  return true;
+}
+
+jint JniInvocation::JNI_GetDefaultJavaVMInitArgs(void* vmargs) {
+  return JNI_GetDefaultJavaVMInitArgs_(vmargs);
+}
+
+jint JniInvocation::JNI_CreateJavaVM(JavaVM** p_vm, JNIEnv** p_env, void* vm_args) {
+  return JNI_CreateJavaVM_(p_vm, p_env, vm_args);
+}
+
+jint JniInvocation::JNI_GetCreatedJavaVMs(JavaVM** vms, jsize size, jsize* vm_count) {
+  return JNI_GetCreatedJavaVMs_(vms, size, vm_count);
+}
+
+bool JniInvocation::FindSymbol(void** pointer, const char* symbol) {
+  *pointer = dlsym(handle_, symbol);
+  if (*pointer == NULL) {
+    ALOGE("Failed to find symbol %s: %s\n", symbol, dlerror());
+    dlclose(handle_);
+    handle_ = NULL;
+    return false;
+  }
+  return true;
+}
+
+JniInvocation& JniInvocation::GetJniInvocation() {
+  LOG_ALWAYS_FATAL_IF(jni_invocation_ == NULL,
+                      "Failed to create JniInvocation instance before using JNI invocation API");
+  return *jni_invocation_;
+}
+
+extern "C" jint JNI_GetDefaultJavaVMInitArgs(void* vm_args) {
+  return JniInvocation::GetJniInvocation().JNI_GetDefaultJavaVMInitArgs(vm_args);
+}
+
+extern "C" jint JNI_CreateJavaVM(JavaVM** p_vm, JNIEnv** p_env, void* vm_args) {
+  return JniInvocation::GetJniInvocation().JNI_CreateJavaVM(p_vm, p_env, vm_args);
+}
+
+extern "C" jint JNI_GetCreatedJavaVMs(JavaVM** vms, jsize size, jsize* vm_count) {
+  return JniInvocation::GetJniInvocation().JNI_GetCreatedJavaVMs(vms, size, vm_count);
+}