1 /*
2  * Copyright (C) 2015 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 #ifndef SYSTEM_CORE_INCLUDE_BINDERWRAPPER_STUB_BINDER_WRAPPER_H_
18 #define SYSTEM_CORE_INCLUDE_BINDERWRAPPER_STUB_BINDER_WRAPPER_H_
19 
20 #include <map>
21 #include <string>
22 #include <vector>
23 
24 #include <binder/Binder.h>
25 #include <binder/IBinder.h>
26 #include <binderwrapper/binder_wrapper.h>
27 
28 namespace android {
29 
30 // Stub implementation of BinderWrapper for testing.
31 //
32 // Example usage:
33 //
34 // First, assuming a base IFoo binder interface, create a stub class that
35 // derives from BnFoo to implement the receiver side of the communication:
36 //
37 //   class StubFoo : public BnFoo {
38 //    public:
39 //     ...
40 //     status_t doSomething(int arg) override {
41 //       // e.g. save passed-in value for later inspection by tests.
42 //       return OK;
43 //     }
44 //   };
45 //
46 // Next, from your test code, inject a StubBinderManager either directly or by
47 // inheriting from the BinderTestBase class:
48 //
49 //   StubBinderWrapper* wrapper = new StubBinderWrapper();
50 //   BinderWrapper::InitForTesting(wrapper);  // Takes ownership.
51 //
52 // Also from your test, create a StubFoo and register it with the wrapper:
53 //
54 //   StubFoo* foo = new StubFoo();
55 //   sp<IBinder> binder(foo);
56 //   wrapper->SetBinderForService("foo", binder);
57 //
58 // The code being tested can now use the wrapper to get the stub and call it:
59 //
60 //   sp<IBinder> binder = BinderWrapper::Get()->GetService("foo");
61 //   CHECK(binder.get());
62 //   sp<IFoo> foo = interface_cast<IFoo>(binder);
63 //   CHECK_EQ(foo->doSomething(3), OK);
64 //
65 // To create a local BBinder object, production code can call
66 // CreateLocalBinder(). Then, a test can get the BBinder's address via
67 // local_binders() to check that they're passed as expected in binder calls.
68 //
69 class StubBinderWrapper : public BinderWrapper {
70  public:
71   StubBinderWrapper();
72   ~StubBinderWrapper() override;
73 
local_binders()74   const std::vector<sp<BBinder>>& local_binders() const {
75     return local_binders_;
76   }
clear_local_binders()77   void clear_local_binders() { local_binders_.clear(); }
78 
set_calling_uid(uid_t uid)79   void set_calling_uid(uid_t uid) { calling_uid_ = uid; }
set_calling_pid(pid_t pid)80   void set_calling_pid(pid_t pid) { calling_pid_ = pid; }
81 
82   // Sets the binder to return when |service_name| is passed to GetService() or
83   // WaitForService().
84   void SetBinderForService(const std::string& service_name,
85                            const sp<IBinder>& binder);
86 
87   // Returns the binder previously registered for |service_name| via
88   // RegisterService(), or null if the service hasn't been registered.
89   sp<IBinder> GetRegisteredService(const std::string& service_name) const;
90 
91   // Run the calback in |death_callbacks_| corresponding to |binder|.
92   void NotifyAboutBinderDeath(const sp<IBinder>& binder);
93 
94   // BinderWrapper:
95   sp<IBinder> GetService(const std::string& service_name) override;
96   bool RegisterService(const std::string& service_name,
97                        const sp<IBinder>& binder) override;
98   sp<BBinder> CreateLocalBinder() override;
99   bool RegisterForDeathNotifications(const sp<IBinder>& binder,
100                                      const std::function<void()>& callback) override;
101   bool UnregisterForDeathNotifications(const sp<IBinder>& binder) override;
102   uid_t GetCallingUid() override;
103   pid_t GetCallingPid() override;
104 
105  private:
106   using ServiceMap = std::map<std::string, sp<IBinder>>;
107 
108   // Map from service name to associated binder handle. Used by GetService() and
109   // WaitForService().
110   ServiceMap services_to_return_;
111 
112   // Map from service name to associated binder handle. Updated by
113   // RegisterService().
114   ServiceMap registered_services_;
115 
116   // Local binders returned by CreateLocalBinder().
117   std::vector<sp<BBinder>> local_binders_;
118 
119   // Map from binder handle to the callback that should be invoked on binder
120   // death.
121   std::map<sp<IBinder>, std::function<void()>> death_callbacks_;
122 
123   // Values to return from GetCallingUid() and GetCallingPid();
124   uid_t calling_uid_;
125   pid_t calling_pid_;
126 
127   StubBinderWrapper(const StubBinderWrapper&) = delete;
128 };
129 
130 }  // namespace android
131 
132 #endif  // SYSTEM_CORE_INCLUDE_BINDERWRAPPER_STUB_BINDER_WRAPPER_H_
133