| /* |
| * 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. |
| */ |
| |
| #define LOG_TAG "SharedMemory" |
| |
| #include "core_jni_helpers.h" |
| |
| #include <cutils/ashmem.h> |
| #include <utils/Log.h> |
| #include <nativehelper/JNIHelp.h> |
| #include <nativehelper/JniConstants.h> |
| #include <nativehelper/ScopedLocalRef.h> |
| |
| #include <algorithm> |
| #include <errno.h> |
| #include <limits> |
| #include <unistd.h> |
| |
| namespace { |
| |
| static void throwErrnoException(JNIEnv* env, const char* functionName, int error) { |
| static jmethodID ctor = env->GetMethodID(JniConstants::errnoExceptionClass, |
| "<init>", "(Ljava/lang/String;I)V"); |
| |
| ScopedLocalRef<jstring> detailMessage(env, env->NewStringUTF(functionName)); |
| if (detailMessage.get() == NULL) { |
| // Not really much we can do here. We're probably dead in the water, |
| // but let's try to stumble on... |
| env->ExceptionClear(); |
| } |
| |
| jobject exception = env->NewObject(JniConstants::errnoExceptionClass, ctor, |
| detailMessage.get(), error); |
| env->Throw(reinterpret_cast<jthrowable>(exception)); |
| } |
| |
| static jobject SharedMemory_create(JNIEnv* env, jobject, jstring jname, jint size) { |
| |
| // Name is optional so we can't use ScopedUtfChars for this as it throws NPE on null |
| const char* name = jname ? env->GetStringUTFChars(jname, nullptr) : nullptr; |
| |
| int fd = ashmem_create_region(name, size); |
| |
| // Capture the error, if there is one, before calling ReleaseStringUTFChars |
| int err = fd < 0 ? errno : 0; |
| |
| if (name) { |
| env->ReleaseStringUTFChars(jname, name); |
| } |
| |
| if (fd < 0) { |
| throwErrnoException(env, "SharedMemory_create", err); |
| return nullptr; |
| } |
| |
| return jniCreateFileDescriptor(env, fd); |
| } |
| |
| static jint SharedMemory_getSize(JNIEnv* env, jobject, jobject fileDescriptor) { |
| int fd = jniGetFDFromFileDescriptor(env, fileDescriptor); |
| if (!ashmem_valid(fd)) { |
| return -1; |
| } |
| size_t size = ashmem_get_size_region(fd); |
| return static_cast<jint>(std::min(size, static_cast<size_t>(std::numeric_limits<jint>::max()))); |
| } |
| |
| static jint SharedMemory_setProt(JNIEnv* env, jobject, jobject fileDescriptor, jint prot) { |
| int fd = jniGetFDFromFileDescriptor(env, fileDescriptor); |
| int err = 0; |
| if (ashmem_set_prot_region(fd, prot)) { |
| err = errno; |
| } |
| return err; |
| } |
| |
| static const JNINativeMethod methods[] = { |
| {"nCreate", "(Ljava/lang/String;I)Ljava/io/FileDescriptor;", (void*)SharedMemory_create}, |
| {"nGetSize", "(Ljava/io/FileDescriptor;)I", (void*)SharedMemory_getSize}, |
| {"nSetProt", "(Ljava/io/FileDescriptor;I)I", (void*)SharedMemory_setProt}, |
| }; |
| |
| } // anonymous namespace |
| |
| namespace android { |
| |
| int register_android_os_SharedMemory(JNIEnv* env) |
| { |
| return RegisterMethodsOrDie(env, "android/os/SharedMemory", methods, NELEM(methods)); |
| } |
| |
| } // namespace android |