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/*
* 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 <nativehelper/JniInvocation.h>
#include <dlfcn.h>
#include <stdlib.h>
#include <string.h>
#include <cstddef>
#define LOG_TAG "JniInvocation"
#include "cutils/log.h"
#ifdef __ANDROID__
#include <sys/system_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_);
}
}
#ifdef __ANDROID__
static const char* kLibrarySystemProperty = "persist.sys.dalvik.vm.lib.2";
static const char* kDebuggableSystemProperty = "ro.debuggable";
#endif
static const char* kLibraryFallback = "libart.so";
template<typename T> void UNUSED(const T&) {}
const char* JniInvocation::GetLibrary(const char* library, char* buffer) {
#ifdef __ANDROID__
const char* default_library;
char debuggable[PROP_VALUE_MAX];
__system_property_get(kDebuggableSystemProperty, debuggable);
if (strcmp(debuggable, "1") != 0) {
// Not a debuggable build.
// Do not allow arbitrary library. Ignore the library parameter. This
// will also ignore the default library, but initialize to fallback
// for cleanliness.
library = kLibraryFallback;
default_library = kLibraryFallback;
} else {
// Debuggable build.
// Accept the library parameter. For the case it is NULL, load the default
// library from the system property.
if (buffer != NULL) {
if (__system_property_get(kLibrarySystemProperty, buffer) > 0) {
default_library = buffer;
} else {
default_library = kLibraryFallback;
}
} else {
// No buffer given, just use default fallback.
default_library = kLibraryFallback;
}
}
#else
UNUSED(buffer);
const char* default_library = kLibraryFallback;
#endif
if (library == NULL) {
library = default_library;
}
return library;
}
bool JniInvocation::Init(const char* library) {
#ifdef __ANDROID__
char buffer[PROP_VALUE_MAX];
#else
char* buffer = NULL;
#endif
library = GetLibrary(library, buffer);
// Load with RTLD_NODELETE in order to ensure that libart.so is not unmapped when it is closed.
// This is due to the fact that it is possible that some threads might have yet to finish
// exiting even after JNI_DeleteJavaVM returns, which can lead to segfaults if the library is
// unloaded.
const int kDlopenFlags = RTLD_NOW | RTLD_NODELETE;
handle_ = dlopen(library, kDlopenFlags);
if (handle_ == NULL) {
if (strcmp(library, kLibraryFallback) == 0) {
// Nothing else to try.
ALOGE("Failed to dlopen %s: %s", library, dlerror());
return false;
}
// Note that this is enough to get something like the zygote
// running, we can't property_set here to fix this for the future
// because we are root and not the system user. See
// RuntimeInit.commonInit for where we fix up the property to
// avoid future fallbacks. http://b/11463182
ALOGW("Falling back from %s to %s after dlopen error: %s",
library, kLibraryFallback, dlerror());
library = kLibraryFallback;
handle_ = dlopen(library, kDlopenFlags);
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);
}