ServiceManagement.cpp revision cbefd35d5c607fa245855ce897ae08369e667222 
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 "ServiceManagement"
18
19#include <hidl/HidlBinderSupport.h>
20#include <hidl/ServiceManagement.h>
21#include <hidl/Static.h>
22#include <hidl/Status.h>
23
24#include <android-base/logging.h>
25#include <condition_variable>
26#include <dlfcn.h>
27#include <dirent.h>
28#include <hidl-util/FQName.h>
29#include <hidl-util/StringHelper.h>
30#include <hwbinder/IPCThreadState.h>
31#include <hwbinder/Parcel.h>
32#include <mutex>
33#include <unistd.h>
34
35#include <android/hidl/manager/1.0/IServiceManager.h>
36#include <android/hidl/manager/1.0/BpHwServiceManager.h>
37#include <android/hidl/manager/1.0/BnHwServiceManager.h>
38
39using android::hidl::manager::V1_0::IServiceManager;
40using android::hidl::manager::V1_0::IServiceNotification;
41using android::hidl::manager::V1_0::BpHwServiceManager;
42using android::hidl::manager::V1_0::BnHwServiceManager;
43
44namespace android {
45namespace hardware {
46
47sp<IServiceManager> defaultServiceManager() {
48
49    if (gDefaultServiceManager != NULL) return gDefaultServiceManager;
50    if (access("/dev/hwbinder", F_OK|R_OK|W_OK) != 0) {
51        // HwBinder not available on this device or not accessible to
52        // this process.
53        return nullptr;
54    }
55    {
56        AutoMutex _l(gDefaultServiceManagerLock);
57        while (gDefaultServiceManager == NULL) {
58            gDefaultServiceManager = fromBinder<IServiceManager, BpHwServiceManager, BnHwServiceManager>(
59                ProcessState::self()->getContextObject(NULL));
60            if (gDefaultServiceManager == NULL)
61                sleep(1);
62        }
63    }
64
65    return gDefaultServiceManager;
66}
67
68std::vector<std::string> search(const std::string &path,
69                              const std::string &prefix,
70                              const std::string &suffix) {
71    std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(path.c_str()), closedir);
72    if (!dir) return {};
73
74    std::vector<std::string> results{};
75
76    dirent* dp;
77    while ((dp = readdir(dir.get())) != nullptr) {
78        std::string name = dp->d_name;
79
80        if (StringHelper::StartsWith(name, prefix) &&
81                StringHelper::EndsWith(name, suffix)) {
82            results.push_back(name);
83        }
84    }
85
86    return results;
87}
88
89struct PassthroughServiceManager : IServiceManager {
90    Return<sp<IBase>> get(const hidl_string& fqName,
91                     const hidl_string& name) override {
92        FQName iface(fqName);
93
94        if (!iface.isValid() ||
95            !iface.isFullyQualified() ||
96            iface.isIdentifier()) {
97            LOG(ERROR) << "Invalid interface name passthrough lookup: " << fqName;
98            return nullptr;
99        }
100
101        const int dlMode = RTLD_LAZY;
102        void *handle = nullptr;
103
104        std::string library;
105
106        // TODO: lookup in VINTF instead
107        // TODO(b/34135607): Remove HAL_LIBRARY_PATH_SYSTEM
108
109        for (const std::string &path : {
110            HAL_LIBRARY_PATH_ODM, HAL_LIBRARY_PATH_VENDOR, HAL_LIBRARY_PATH_SYSTEM
111        }) {
112            const std::string prefix = iface.getPackageAndVersion().string() + "-impl";
113
114            std::vector<std::string> libs = search(path, prefix, ".so");
115
116            if (libs.size() > 1) {
117                LOG(WARNING) << "Multiple libraries found: " << StringHelper::JoinStrings(libs, ", ");
118            }
119
120            for (const std::string &lib : libs) {
121                handle = dlopen((path + lib).c_str(), dlMode);
122                if (handle != nullptr) {
123                    library = lib;
124                    goto beginLookup;
125                }
126            }
127        }
128
129        if (handle == nullptr) {
130            return nullptr;
131        }
132beginLookup:
133
134        const std::string sym = "HIDL_FETCH_" + iface.name();
135
136        IBase* (*generator)(const char* name);
137        *(void **)(&generator) = dlsym(handle, sym.c_str());
138        if(!generator) {
139            LOG(ERROR) << "Passthrough lookup opened " << library
140                       << " but could not find symbol " << sym;
141            return nullptr;
142        }
143        return (*generator)(name);
144    }
145
146    Return<bool> add(const hidl_vec<hidl_string>& /* interfaceChain */,
147                     const hidl_string& /* name */,
148                     const sp<IBase>& /* service */) override {
149        LOG(FATAL) << "Cannot register services with passthrough service manager.";
150        return false;
151    }
152
153    Return<void> list(list_cb /* _hidl_cb */) override {
154        // TODO: add this functionality
155        LOG(FATAL) << "Cannot list services with passthrough service manager.";
156        return Void();
157    }
158    Return<void> listByInterface(const hidl_string& /* fqInstanceName */,
159                                 listByInterface_cb /* _hidl_cb */) override {
160        // TODO: add this functionality
161        LOG(FATAL) << "Cannot list services with passthrough service manager.";
162        return Void();
163    }
164
165    Return<bool> registerForNotifications(const hidl_string& /* fqName */,
166                                          const hidl_string& /* name */,
167                                          const sp<IServiceNotification>& /* callback */) override {
168        // This makes no sense.
169        LOG(FATAL) << "Cannot register for notifications with passthrough service manager.";
170        return false;
171    }
172
173};
174
175sp<IServiceManager> getPassthroughServiceManager() {
176    static sp<PassthroughServiceManager> manager(new PassthroughServiceManager());
177    return manager;
178}
179
180namespace details {
181
182struct Waiter : IServiceNotification {
183    Return<void> onRegistration(const hidl_string& /* fqName */,
184                                const hidl_string& /* name */,
185                                bool /* preexisting */) override {
186        std::unique_lock<std::mutex> lock(mMutex);
187        if (mRegistered) {
188            return Void();
189        }
190        mRegistered = true;
191        lock.unlock();
192
193        mCondition.notify_one();
194        return Void();
195    }
196
197    void wait() {
198        std::unique_lock<std::mutex> lock(mMutex);
199        mCondition.wait(lock, [this]{
200            return mRegistered;
201        });
202    }
203
204private:
205    std::mutex mMutex;
206    std::condition_variable mCondition;
207    bool mRegistered = false;
208};
209
210void waitForHwService(
211        const std::string &interface, const std::string &instanceName) {
212    const sp<IServiceManager> manager = defaultServiceManager();
213
214    if (manager == nullptr) {
215        LOG(ERROR) << "Could not get default service manager.";
216        return;
217    }
218
219    sp<Waiter> waiter = new Waiter();
220    Return<bool> ret = manager->registerForNotifications(interface, instanceName, waiter);
221
222    if (!ret.isOk()) {
223        LOG(ERROR) << "Transport error, " << ret.description()
224            << ", during notification registration for "
225            << interface << "/" << instanceName << ".";
226        return;
227    }
228
229    if (!ret) {
230        LOG(ERROR) << "Could not register for notifications for "
231            << interface << "/" << instanceName << ".";
232        return;
233    }
234
235    waiter->wait();
236}
237
238}; // namespace details
239
240}; // namespace hardware
241}; // namespace android
242