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 specic language governing permissions and
14 * limitations under the License.
15 */
16
17// Need to use LOGE_EX.
18#define LOG_TAG "AppFuseBridge"
19
20#include <android_runtime/Log.h>
21#include <android-base/logging.h>
22#include <android-base/unique_fd.h>
23#include <core_jni_helpers.h>
24#include <libappfuse/FuseBridgeLoop.h>
25#include <libappfuse/FuseBuffer.h>
26#include <nativehelper/JNIHelp.h>
27
28namespace android {
29namespace {
30
31constexpr const char* CLASS_NAME = "com/android/server/storage/AppFuseBridge";
32static jclass gAppFuseClass;
33static jmethodID gAppFuseOnMount;
34static jmethodID gAppFuseOnClosed;
35
36class Callback : public fuse::FuseBridgeLoopCallback {
37    JNIEnv* mEnv;
38    jobject mSelf;
39
40public:
41    Callback(JNIEnv* env, jobject self) : mEnv(env), mSelf(self) {}
42    void OnMount(int mount_id) override {
43        mEnv->CallVoidMethod(mSelf, gAppFuseOnMount, mount_id);
44        if (mEnv->ExceptionCheck()) {
45            LOGE_EX(mEnv, nullptr);
46            mEnv->ExceptionClear();
47        }
48    }
49
50    void OnClosed(int mount_id) override {
51        mEnv->CallVoidMethod(mSelf, gAppFuseOnClosed, mount_id);
52        if (mEnv->ExceptionCheck()) {
53            LOGE_EX(mEnv, nullptr);
54            mEnv->ExceptionClear();
55        }
56    }
57};
58
59class MonitorScope final {
60public:
61    MonitorScope(JNIEnv* env, jobject obj) : mEnv(env), mObj(obj), mLocked(false) {
62        if (mEnv->MonitorEnter(obj) == JNI_OK) {
63            mLocked = true;
64        } else {
65            LOG(ERROR) << "Failed to enter monitor.";
66        }
67    }
68
69    ~MonitorScope() {
70        if (mLocked) {
71            if (mEnv->MonitorExit(mObj) != JNI_OK) {
72                LOG(ERROR) << "Failed to exit monitor.";
73            }
74        }
75    }
76
77    operator bool() {
78        return mLocked;
79    }
80
81private:
82    // Lifetime of |MonitorScope| must be shorter than the reference of mObj.
83    JNIEnv* mEnv;
84    jobject mObj;
85    bool mLocked;
86
87    DISALLOW_COPY_AND_ASSIGN(MonitorScope);
88};
89
90jlong com_android_server_storage_AppFuseBridge_new(JNIEnv* env, jobject self) {
91    return reinterpret_cast<jlong>(new fuse::FuseBridgeLoop());
92}
93
94void com_android_server_storage_AppFuseBridge_delete(JNIEnv* env, jobject self, jlong java_loop) {
95    fuse::FuseBridgeLoop* const loop = reinterpret_cast<fuse::FuseBridgeLoop*>(java_loop);
96    CHECK(loop);
97    delete loop;
98}
99
100void com_android_server_storage_AppFuseBridge_start_loop(
101        JNIEnv* env, jobject self, jlong java_loop) {
102    fuse::FuseBridgeLoop* const loop = reinterpret_cast<fuse::FuseBridgeLoop*>(java_loop);
103    CHECK(loop);
104    Callback callback(env, self);
105    loop->Start(&callback);
106}
107
108jint com_android_server_storage_AppFuseBridge_add_bridge(
109        JNIEnv* env, jobject self, jlong java_loop, jint mountId, jint javaDevFd) {
110    base::unique_fd devFd(javaDevFd);
111    fuse::FuseBridgeLoop* const loop = reinterpret_cast<fuse::FuseBridgeLoop*>(java_loop);
112    CHECK(loop);
113
114    base::unique_fd proxyFd[2];
115    if (!fuse::SetupMessageSockets(&proxyFd)) {
116        return -1;
117    }
118
119    if (!loop->AddBridge(mountId, std::move(devFd), std::move(proxyFd[0]))) {
120        return -1;
121    }
122
123    return proxyFd[1].release();
124}
125
126const JNINativeMethod methods[] = {
127    {
128        "native_new",
129        "()J",
130        reinterpret_cast<void*>(com_android_server_storage_AppFuseBridge_new)
131    },
132    {
133        "native_delete",
134        "(J)V",
135        reinterpret_cast<void*>(com_android_server_storage_AppFuseBridge_delete)
136    },
137    {
138        "native_start_loop",
139        "(J)V",
140        reinterpret_cast<void*>(com_android_server_storage_AppFuseBridge_start_loop)
141    },
142    {
143        "native_add_bridge",
144        "(JII)I",
145        reinterpret_cast<void*>(com_android_server_storage_AppFuseBridge_add_bridge)
146    }
147};
148
149}  // namespace
150
151void register_android_server_storage_AppFuse(JNIEnv* env) {
152    CHECK(env != nullptr);
153
154    gAppFuseClass = MakeGlobalRefOrDie(env, FindClassOrDie(env, CLASS_NAME));
155    gAppFuseOnMount = GetMethodIDOrDie(env, gAppFuseClass, "onMount", "(I)V");
156    gAppFuseOnClosed = GetMethodIDOrDie(env, gAppFuseClass, "onClosed", "(I)V");
157    RegisterMethodsOrDie(env, CLASS_NAME, methods, NELEM(methods));
158}
159}  // namespace android
160