/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "nativehelper/JniInvocation.h"
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#ifdef _WIN32
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#include <windows.h>
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#else
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#include <dlfcn.h>
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <cstddef>
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#define LOG_TAG "JniInvocation"
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#include <log/log.h>
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#ifdef __ANDROID__
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#include <sys/system_properties.h>
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#endif
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#include "android-base/errors.h"
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#include "JniConstants.h"
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namespace {
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template <typename T>
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void UNUSED(const T&) {}
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bool IsDebuggable() {
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#ifdef __ANDROID__
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char debuggable[PROP_VALUE_MAX] = {0};
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__system_property_get("ro.debuggable", debuggable);
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return strcmp(debuggable, "1") == 0;
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#else
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return false;
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#endif
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}
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int GetLibrarySystemProperty(char* buffer) {
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#ifdef __ANDROID__
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return __system_property_get("persist.sys.dalvik.vm.lib.2", buffer);
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#else
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UNUSED(buffer);
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return 0;
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#endif
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}
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#ifdef _WIN32
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#define FUNC_POINTER FARPROC
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#else
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#define FUNC_POINTER void*
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#endif
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void* OpenLibrary(const char* filename) {
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#ifdef _WIN32
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return LoadLibrary(filename);
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#else
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// Load with RTLD_NODELETE in order to ensure that libart.so is not unmapped when it is closed.
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// This is due to the fact that it is possible that some threads might have yet to finish
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// exiting even after JNI_DeleteJavaVM returns, which can lead to segfaults if the library is
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// unloaded.
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const int kDlopenFlags = RTLD_NOW | RTLD_NODELETE;
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return dlopen(filename, kDlopenFlags);
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#endif
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}
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int CloseLibrary(void* handle) {
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#ifdef _WIN32
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return FreeLibrary(static_cast<HMODULE>(handle));
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#else
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return dlclose(handle);
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#endif
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}
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FUNC_POINTER GetSymbol(void* handle, const char* symbol) {
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#ifdef _WIN32
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return GetProcAddress(static_cast<HMODULE>(handle), symbol);
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#else
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return dlsym(handle, symbol);
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#endif
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}
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std::string GetError() {
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#ifdef _WIN32
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return android::base::SystemErrorCodeToString(GetLastError());
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#else
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return std::string(dlerror());
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#endif
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}
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} // namespace
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struct JniInvocationImpl final {
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public:
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JniInvocationImpl();
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~JniInvocationImpl();
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bool Init(const char* library);
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// static const char* GetLibrary(const char* library, char* buffer);
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static const char* GetLibrary(const char* library,
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char* buffer,
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bool (*is_debuggable)() = IsDebuggable,
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int (*get_library_system_property)(char* buffer) = GetLibrarySystemProperty);
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static JniInvocationImpl& GetJniInvocation();
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jint JNI_GetDefaultJavaVMInitArgs(void* vmargs);
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jint JNI_CreateJavaVM(JavaVM** p_vm, JNIEnv** p_env, void* vm_args);
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jint JNI_GetCreatedJavaVMs(JavaVM** vms, jsize size, jsize* vm_count);
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private:
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JniInvocationImpl(const JniInvocationImpl&) = delete;
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JniInvocationImpl& operator=(const JniInvocationImpl&) = delete;
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bool FindSymbol(FUNC_POINTER* pointer, const char* symbol);
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static JniInvocationImpl* jni_invocation_;
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// Handle to library opened with dlopen(). Library exports
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// JNI_GetDefaultJavaVMInitArgs, JNI_CreateJavaVM, JNI_GetCreatedJavaVMs.
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void* handle_;
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jint (*JNI_GetDefaultJavaVMInitArgs_)(void*);
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jint (*JNI_CreateJavaVM_)(JavaVM**, JNIEnv**, void*);
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jint (*JNI_GetCreatedJavaVMs_)(JavaVM**, jsize, jsize*);
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friend class JNIInvocation_Debuggable_Test;
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friend class JNIInvocation_NonDebuggable_Test;
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};
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// Check JniInvocationImpl size is same as fields, e.g. no vtable present.
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static_assert(sizeof(JniInvocationImpl) == 4 * sizeof(uintptr_t));
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JniInvocationImpl* JniInvocationImpl::jni_invocation_ = NULL;
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JniInvocationImpl::JniInvocationImpl() :
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handle_(NULL),
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JNI_GetDefaultJavaVMInitArgs_(NULL),
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JNI_CreateJavaVM_(NULL),
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JNI_GetCreatedJavaVMs_(NULL) {
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LOG_ALWAYS_FATAL_IF(jni_invocation_ != NULL, "JniInvocation instance already initialized");
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jni_invocation_ = this;
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}
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JniInvocationImpl::~JniInvocationImpl() {
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jni_invocation_ = NULL;
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if (handle_ != NULL) {
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CloseLibrary(handle_);
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}
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}
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static const char* kLibraryFallback = "libart.so";
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const char* JniInvocationImpl::GetLibrary(const char* library,
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char* buffer,
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bool (*is_debuggable)(),
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int (*get_library_system_property)(char* buffer)) {
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#ifdef __ANDROID__
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const char* default_library;
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if (!is_debuggable()) {
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// Not a debuggable build.
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// Do not allow arbitrary library. Ignore the library parameter. This
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// will also ignore the default library, but initialize to fallback
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// for cleanliness.
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library = kLibraryFallback;
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default_library = kLibraryFallback;
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} else {
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// Debuggable build.
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// Accept the library parameter. For the case it is NULL, load the default
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// library from the system property.
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if (buffer != NULL) {
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if (get_library_system_property(buffer) > 0) {
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default_library = buffer;
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} else {
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default_library = kLibraryFallback;
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}
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} else {
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// No buffer given, just use default fallback.
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default_library = kLibraryFallback;
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}
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}
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#else
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UNUSED(buffer);
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UNUSED(is_debuggable);
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UNUSED(get_library_system_property);
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const char* default_library = kLibraryFallback;
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#endif
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if (library == NULL) {
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library = default_library;
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}
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return library;
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}
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bool JniInvocationImpl::Init(const char* library) {
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#ifdef __ANDROID__
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char buffer[PROP_VALUE_MAX];
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#else
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char* buffer = NULL;
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#endif
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library = GetLibrary(library, buffer);
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handle_ = OpenLibrary(library);
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if (handle_ == NULL) {
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if (strcmp(library, kLibraryFallback) == 0) {
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// Nothing else to try.
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ALOGE("Failed to dlopen %s: %s", library, GetError().c_str());
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return false;
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}
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// Note that this is enough to get something like the zygote
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// running, we can't property_set here to fix this for the future
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// because we are root and not the system user. See
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// RuntimeInit.commonInit for where we fix up the property to
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// avoid future fallbacks. http://b/11463182
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ALOGW("Falling back from %s to %s after dlopen error: %s",
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library, kLibraryFallback, GetError().c_str());
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library = kLibraryFallback;
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handle_ = OpenLibrary(library);
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if (handle_ == NULL) {
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ALOGE("Failed to dlopen %s: %s", library, GetError().c_str());
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return false;
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}
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}
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if (!FindSymbol(reinterpret_cast<FUNC_POINTER*>(&JNI_GetDefaultJavaVMInitArgs_),
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"JNI_GetDefaultJavaVMInitArgs")) {
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return false;
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}
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if (!FindSymbol(reinterpret_cast<FUNC_POINTER*>(&JNI_CreateJavaVM_),
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"JNI_CreateJavaVM")) {
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return false;
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}
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if (!FindSymbol(reinterpret_cast<FUNC_POINTER*>(&JNI_GetCreatedJavaVMs_),
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"JNI_GetCreatedJavaVMs")) {
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return false;
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}
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return true;
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}
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jint JniInvocationImpl::JNI_GetDefaultJavaVMInitArgs(void* vmargs) {
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return JNI_GetDefaultJavaVMInitArgs_(vmargs);
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}
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jint JniInvocationImpl::JNI_CreateJavaVM(JavaVM** p_vm, JNIEnv** p_env, void* vm_args) {
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return JNI_CreateJavaVM_(p_vm, p_env, vm_args);
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}
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jint JniInvocationImpl::JNI_GetCreatedJavaVMs(JavaVM** vms, jsize size, jsize* vm_count) {
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return JNI_GetCreatedJavaVMs_(vms, size, vm_count);
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}
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bool JniInvocationImpl::FindSymbol(FUNC_POINTER* pointer, const char* symbol) {
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*pointer = GetSymbol(handle_, symbol);
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if (*pointer == NULL) {
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ALOGE("Failed to find symbol %s: %s\n", symbol, GetError().c_str());
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CloseLibrary(handle_);
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handle_ = NULL;
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return false;
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}
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return true;
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}
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JniInvocationImpl& JniInvocationImpl::GetJniInvocation() {
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LOG_ALWAYS_FATAL_IF(jni_invocation_ == NULL,
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"Failed to create JniInvocation instance before using JNI invocation API");
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return *jni_invocation_;
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}
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MODULE_API jint JNI_GetDefaultJavaVMInitArgs(void* vm_args) {
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return JniInvocationImpl::GetJniInvocation().JNI_GetDefaultJavaVMInitArgs(vm_args);
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}
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MODULE_API jint JNI_CreateJavaVM(JavaVM** p_vm, JNIEnv** p_env, void* vm_args) {
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// Ensure any cached heap objects from previous VM instances are
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// invalidated. There is no notification here that a VM is destroyed. These
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// cached objects limit us to one VM instance per process.
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JniConstants::Uninitialize();
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return JniInvocationImpl::GetJniInvocation().JNI_CreateJavaVM(p_vm, p_env, vm_args);
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}
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MODULE_API jint JNI_GetCreatedJavaVMs(JavaVM** vms, jsize size, jsize* vm_count) {
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return JniInvocationImpl::GetJniInvocation().JNI_GetCreatedJavaVMs(vms, size, vm_count);
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}
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MODULE_API JniInvocationImpl* JniInvocationCreate() {
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return new JniInvocationImpl();
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}
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MODULE_API void JniInvocationDestroy(JniInvocationImpl* instance) {
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delete instance;
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}
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MODULE_API int JniInvocationInit(JniInvocationImpl* instance, const char* library) {
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return instance->Init(library) ? 1 : 0;
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}
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MODULE_API const char* JniInvocationGetLibrary(const char* library, char* buffer) {
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return JniInvocationImpl::GetLibrary(library, buffer);
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}
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MODULE_API const char* JniInvocation::GetLibrary(const char* library,
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char* buffer,
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bool (*is_debuggable)(),
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int (*get_library_system_property)(char* buffer)) {
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return JniInvocationImpl::GetLibrary(library, buffer, is_debuggable, get_library_system_property);
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}
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