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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #define LOG_TAG "FuseAppLoopJNI"
     18 #define LOG_NDEBUG 0
     19 
     20 #include <stdlib.h>
     21 #include <sys/stat.h>
     22 
     23 #include <map>
     24 #include <memory>
     25 
     26 #include <android_runtime/Log.h>
     27 #include <android-base/logging.h>
     28 #include <android-base/unique_fd.h>
     29 #include <jni.h>
     30 #include <libappfuse/FuseAppLoop.h>
     31 #include <nativehelper/ScopedLocalRef.h>
     32 #include <nativehelper/ScopedPrimitiveArray.h>
     33 
     34 #include "core_jni_helpers.h"
     35 
     36 namespace android {
     37 namespace {
     38 constexpr const char* CLASS_NAME = "com/android/internal/os/FuseAppLoop";
     39 
     40 jclass gFuseAppLoopClass;
     41 jmethodID gOnCommandMethod;
     42 jmethodID gOnOpenMethod;
     43 
     44 class Callback : public fuse::FuseAppLoopCallback {
     45 private:
     46     typedef ScopedLocalRef<jbyteArray> LocalBytes;
     47     JNIEnv* const mEnv;
     48     jobject const mSelf;
     49     std::map<uint64_t, std::unique_ptr<LocalBytes>> mBuffers;
     50 
     51 public:
     52     Callback(JNIEnv* env, jobject self) :
     53         mEnv(env), mSelf(self) {}
     54 
     55     void OnLookup(uint64_t unique, uint64_t inode) override {
     56         CallOnCommand(FUSE_LOOKUP, unique, inode, 0, 0, nullptr);
     57     }
     58 
     59     void OnGetAttr(uint64_t unique, uint64_t inode) override {
     60         CallOnCommand(FUSE_GETATTR, unique, inode, 0, 0, nullptr);
     61     }
     62 
     63     void OnOpen(uint64_t unique, uint64_t inode) override {
     64         const jbyteArray buffer = static_cast<jbyteArray>(mEnv->CallObjectMethod(
     65                 mSelf, gOnOpenMethod, unique, inode));
     66         CHECK(!mEnv->ExceptionCheck());
     67         if (buffer == nullptr) {
     68             return;
     69         }
     70 
     71         mBuffers.insert(std::make_pair(inode, std::unique_ptr<LocalBytes>(
     72                 new LocalBytes(mEnv, buffer))));
     73     }
     74 
     75     void OnFsync(uint64_t unique, uint64_t inode) override {
     76         CallOnCommand(FUSE_FSYNC, unique, inode, 0, 0, nullptr);
     77     }
     78 
     79     void OnRelease(uint64_t unique, uint64_t inode) override {
     80         mBuffers.erase(inode);
     81         CallOnCommand(FUSE_RELEASE, unique, inode, 0, 0, nullptr);
     82     }
     83 
     84     void OnRead(uint64_t unique, uint64_t inode, uint64_t offset, uint32_t size) override {
     85         CHECK_LE(size, static_cast<uint32_t>(fuse::kFuseMaxRead));
     86 
     87         auto it = mBuffers.find(inode);
     88         CHECK(it != mBuffers.end());
     89 
     90         CallOnCommand(FUSE_READ, unique, inode, offset, size, it->second->get());
     91     }
     92 
     93     void OnWrite(uint64_t unique, uint64_t inode, uint64_t offset, uint32_t size,
     94             const void* buffer) override {
     95         CHECK_LE(size, static_cast<uint32_t>(fuse::kFuseMaxWrite));
     96 
     97         auto it = mBuffers.find(inode);
     98         CHECK(it != mBuffers.end());
     99 
    100         jbyteArray const javaBuffer = it->second->get();
    101 
    102         mEnv->SetByteArrayRegion(javaBuffer, 0, size, static_cast<const jbyte*>(buffer));
    103         CHECK(!mEnv->ExceptionCheck());
    104 
    105         CallOnCommand(FUSE_WRITE, unique, inode, offset, size, javaBuffer);
    106     }
    107 
    108 private:
    109     // Helper function to make sure we invoke CallVoidMethod with correct size of integer arguments.
    110     void CallOnCommand(jint command, jlong unique, jlong inode, jlong offset, jint size,
    111                        jobject bytes) {
    112         mEnv->CallVoidMethod(mSelf, gOnCommandMethod, command, unique, inode, offset, size, bytes);
    113         CHECK(!mEnv->ExceptionCheck());
    114     }
    115 };
    116 
    117 jlong com_android_internal_os_FuseAppLoop_new(JNIEnv* env, jobject self, jint jfd) {
    118     return reinterpret_cast<jlong>(new fuse::FuseAppLoop(base::unique_fd(jfd)));
    119 }
    120 
    121 void com_android_internal_os_FuseAppLoop_delete(JNIEnv* env, jobject self, jlong ptr) {
    122     delete reinterpret_cast<fuse::FuseAppLoop*>(ptr);
    123 }
    124 
    125 void com_android_internal_os_FuseAppLoop_start(JNIEnv* env, jobject self, jlong ptr) {
    126     Callback callback(env, self);
    127     reinterpret_cast<fuse::FuseAppLoop*>(ptr)->Start(&callback);
    128 }
    129 
    130 void com_android_internal_os_FuseAppLoop_replySimple(
    131         JNIEnv* env, jobject self, jlong ptr, jlong unique, jint result) {
    132     if (!reinterpret_cast<fuse::FuseAppLoop*>(ptr)->ReplySimple(unique, result)) {
    133         reinterpret_cast<fuse::FuseAppLoop*>(ptr)->Break();
    134     }
    135 }
    136 
    137 void com_android_internal_os_FuseAppLoop_replyOpen(
    138         JNIEnv* env, jobject self, jlong ptr, jlong unique, jlong fh) {
    139     if (!reinterpret_cast<fuse::FuseAppLoop*>(ptr)->ReplyOpen(unique, fh)) {
    140         reinterpret_cast<fuse::FuseAppLoop*>(ptr)->Break();
    141     }
    142 }
    143 
    144 void com_android_internal_os_FuseAppLoop_replyLookup(
    145         JNIEnv* env, jobject self, jlong ptr, jlong unique, jlong inode, jlong size) {
    146     if (!reinterpret_cast<fuse::FuseAppLoop*>(ptr)->ReplyLookup(unique, inode, size)) {
    147         reinterpret_cast<fuse::FuseAppLoop*>(ptr)->Break();
    148     }
    149 }
    150 
    151 void com_android_internal_os_FuseAppLoop_replyGetAttr(
    152         JNIEnv* env, jobject self, jlong ptr, jlong unique, jlong inode, jlong size) {
    153     if (!reinterpret_cast<fuse::FuseAppLoop*>(ptr)->ReplyGetAttr(
    154             unique, inode, size, S_IFREG | 0777)) {
    155         reinterpret_cast<fuse::FuseAppLoop*>(ptr)->Break();
    156     }
    157 }
    158 
    159 void com_android_internal_os_FuseAppLoop_replyWrite(
    160         JNIEnv* env, jobject self, jlong ptr, jlong unique, jint size) {
    161     if (!reinterpret_cast<fuse::FuseAppLoop*>(ptr)->ReplyWrite(unique, size)) {
    162         reinterpret_cast<fuse::FuseAppLoop*>(ptr)->Break();
    163     }
    164 }
    165 
    166 void com_android_internal_os_FuseAppLoop_replyRead(
    167         JNIEnv* env, jobject self, jlong ptr, jlong unique, jint size, jbyteArray data) {
    168     ScopedByteArrayRO array(env, data);
    169     CHECK_GE(size, 0);
    170     CHECK_LE(static_cast<size_t>(size), array.size());
    171     if (!reinterpret_cast<fuse::FuseAppLoop*>(ptr)->ReplyRead(unique, size, array.get())) {
    172         reinterpret_cast<fuse::FuseAppLoop*>(ptr)->Break();
    173     }
    174 }
    175 
    176 const JNINativeMethod methods[] = {
    177     {
    178         "native_new",
    179         "(I)J",
    180         reinterpret_cast<void*>(com_android_internal_os_FuseAppLoop_new)
    181     },
    182     {
    183         "native_delete",
    184         "(J)V",
    185         reinterpret_cast<void*>(com_android_internal_os_FuseAppLoop_delete)
    186     },
    187     {
    188         "native_start",
    189         "(J)V",
    190         reinterpret_cast<void*>(com_android_internal_os_FuseAppLoop_start)
    191     },
    192     {
    193         "native_replySimple",
    194         "(JJI)V",
    195         reinterpret_cast<void*>(com_android_internal_os_FuseAppLoop_replySimple)
    196     },
    197     {
    198         "native_replyOpen",
    199         "(JJJ)V",
    200         reinterpret_cast<void*>(com_android_internal_os_FuseAppLoop_replyOpen)
    201     },
    202     {
    203         "native_replyLookup",
    204         "(JJJJ)V",
    205         reinterpret_cast<void*>(com_android_internal_os_FuseAppLoop_replyLookup)
    206     },
    207     {
    208         "native_replyGetAttr",
    209         "(JJJJ)V",
    210         reinterpret_cast<void*>(com_android_internal_os_FuseAppLoop_replyGetAttr)
    211     },
    212     {
    213         "native_replyRead",
    214         "(JJI[B)V",
    215         reinterpret_cast<void*>(com_android_internal_os_FuseAppLoop_replyRead)
    216     },
    217     {
    218         "native_replyWrite",
    219         "(JJI)V",
    220         reinterpret_cast<void*>(com_android_internal_os_FuseAppLoop_replyWrite)
    221     },
    222 };
    223 }  // namespace
    224 
    225 int register_com_android_internal_os_FuseAppLoop(JNIEnv* env) {
    226     gFuseAppLoopClass = MakeGlobalRefOrDie(env, FindClassOrDie(env, CLASS_NAME));
    227     gOnCommandMethod = GetMethodIDOrDie(env, gFuseAppLoopClass, "onCommand", "(IJJJI[B)V");
    228     gOnOpenMethod = GetMethodIDOrDie(env, gFuseAppLoopClass, "onOpen", "(JJ)[B");
    229     RegisterMethodsOrDie(env, CLASS_NAME, methods, NELEM(methods));
    230     return 0;
    231 }
    232 }  // namespace android
    233