/*
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* Copyright (C) 2008 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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#define LOG_TAG "MemoryFile"
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#include <utils/Log.h>
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#include <cutils/ashmem.h>
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#include "core_jni_helpers.h"
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#include <nativehelper/JNIHelp.h>
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#include <unistd.h>
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#include <sys/mman.h>
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namespace android {
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static jboolean android_os_MemoryFile_pin(JNIEnv* env, jobject clazz, jobject fileDescriptor,
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jboolean pin) {
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int fd = jniGetFDFromFileDescriptor(env, fileDescriptor);
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int result = (pin ? ashmem_pin_region(fd, 0, 0) : ashmem_unpin_region(fd, 0, 0));
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if (result < 0) {
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jniThrowException(env, "java/io/IOException", NULL);
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}
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return result == ASHMEM_WAS_PURGED;
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}
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static jint android_os_MemoryFile_get_size(JNIEnv* env, jobject clazz,
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jobject fileDescriptor) {
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int fd = jniGetFDFromFileDescriptor(env, fileDescriptor);
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// Use ASHMEM_GET_SIZE to find out if the fd refers to an ashmem region.
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// ASHMEM_GET_SIZE should succeed for all ashmem regions, and the kernel
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// should return ENOTTY for all other valid file descriptors
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int result = ashmem_get_size_region(fd);
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if (result < 0) {
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if (errno == ENOTTY) {
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// ENOTTY means that the ioctl does not apply to this object,
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// i.e., it is not an ashmem region.
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return (jint) -1;
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}
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// Some other error, throw exception
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jniThrowIOException(env, errno);
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return (jint) -1;
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}
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return (jint) result;
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}
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static const JNINativeMethod methods[] = {
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{"native_pin", "(Ljava/io/FileDescriptor;Z)Z", (void*)android_os_MemoryFile_pin},
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{"native_get_size", "(Ljava/io/FileDescriptor;)I",
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(void*)android_os_MemoryFile_get_size}
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};
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int register_android_os_MemoryFile(JNIEnv* env) {
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return RegisterMethodsOrDie(env, "android/os/MemoryFile", methods, NELEM(methods));
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}
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}
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