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 #ifndef ANDROID_HIDL_INTERNAL_H
18 #define ANDROID_HIDL_INTERNAL_H
19 
20 #include <cstdint>
21 #include <dirent.h>
22 #include <functional>
23 #include <string>
24 #include <vector>
25 #include <utility>
26 
27 namespace android {
28 namespace hardware {
29 namespace details {
30 
31 // tag for pure interfaces (e.x. IFoo)
32 struct i_tag {};
33 
34 // tag for server interfaces (e.x. BnHwFoo)
35 struct bnhw_tag {};
36 
37 // tag for proxy interfaces (e.x. BpHwFoo)
38 struct bphw_tag {};
39 
40 // tag for passthrough interfaces (e.x. BsFoo)
41 struct bs_tag {};
42 
43 //Templated classes can use the below method
44 //to avoid creating dependencies on liblog.
45 void logAlwaysFatal(const char *message);
46 
47 // Returns vndk version from "ro.vndk.version"
48 std::string getVndkVersionStr();
49 
50 // Explicitly invokes the parameterized element's destructor;
51 // intended to be used alongside the placement new operator.
52 template<typename T>
53 void destructElement(T* element) {
54     if (element != nullptr) {
55         element->~T();
56     }
57 }
58 
59 // HIDL client/server code should *NOT* use this class.
60 //
61 // hidl_pointer wraps a pointer without taking ownership,
62 // and stores it in a union with a uint64_t. This ensures
63 // that we always have enough space to store a pointer,
64 // regardless of whether we're running in a 32-bit or 64-bit
65 // process.
66 template<typename T>
67 struct hidl_pointer {
68     hidl_pointer()
69         : _pad(0) {
70         static_assert(sizeof(*this) == 8, "wrong size");
71     }
72     hidl_pointer(T* ptr) : hidl_pointer() { mPointer = ptr; }
73     hidl_pointer(const hidl_pointer<T>& other) : hidl_pointer() { mPointer = other.mPointer; }
74     hidl_pointer(hidl_pointer<T>&& other) noexcept : hidl_pointer() { *this = std::move(other); }
75 
76     hidl_pointer &operator=(const hidl_pointer<T>& other) {
77         mPointer = other.mPointer;
78         return *this;
79     }
80     hidl_pointer& operator=(hidl_pointer<T>&& other) noexcept {
81         mPointer = other.mPointer;
82         other.mPointer = nullptr;
83         return *this;
84     }
85     hidl_pointer &operator=(T* ptr) {
86         mPointer = ptr;
87         return *this;
88     }
89 
90     operator T*() const {
91         return mPointer;
92     }
93     explicit operator void*() const { // requires explicit cast to avoid ambiguity
94         return mPointer;
95     }
96     T& operator*() const {
97         return *mPointer;
98     }
99     T* operator->() const {
100         return mPointer;
101     }
102     T &operator[](size_t index) {
103         return mPointer[index];
104     }
105     const T &operator[](size_t index) const {
106         return mPointer[index];
107     }
108 
109 private:
110     union {
111         T* mPointer;
112         uint64_t _pad;
113     };
114 };
115 
116 #define HAL_LIBRARY_PATH_SYSTEM_64BIT "/system/lib64/hw/"
117 #define HAL_LIBRARY_PATH_VNDK_SP_64BIT_FOR_VERSION "/apex/com.android.vndk.v%s/lib64/hw/"
118 #define HAL_LIBRARY_PATH_VENDOR_64BIT "/vendor/lib64/hw/"
119 #define HAL_LIBRARY_PATH_ODM_64BIT    "/odm/lib64/hw/"
120 #define HAL_LIBRARY_PATH_SYSTEM_32BIT "/system/lib/hw/"
121 #define HAL_LIBRARY_PATH_VNDK_SP_32BIT_FOR_VERSION "/apex/com.android.vndk.v%s/lib/hw/"
122 #define HAL_LIBRARY_PATH_VENDOR_32BIT "/vendor/lib/hw/"
123 #define HAL_LIBRARY_PATH_ODM_32BIT    "/odm/lib/hw/"
124 
125 #if defined(__LP64__)
126 #define HAL_LIBRARY_PATH_SYSTEM HAL_LIBRARY_PATH_SYSTEM_64BIT
127 #define HAL_LIBRARY_PATH_VNDK_SP_FOR_VERSION HAL_LIBRARY_PATH_VNDK_SP_64BIT_FOR_VERSION
128 #define HAL_LIBRARY_PATH_VENDOR HAL_LIBRARY_PATH_VENDOR_64BIT
129 #define HAL_LIBRARY_PATH_ODM    HAL_LIBRARY_PATH_ODM_64BIT
130 #else
131 #define HAL_LIBRARY_PATH_SYSTEM HAL_LIBRARY_PATH_SYSTEM_32BIT
132 #define HAL_LIBRARY_PATH_VNDK_SP_FOR_VERSION HAL_LIBRARY_PATH_VNDK_SP_32BIT_FOR_VERSION
133 #define HAL_LIBRARY_PATH_VENDOR HAL_LIBRARY_PATH_VENDOR_32BIT
134 #define HAL_LIBRARY_PATH_ODM    HAL_LIBRARY_PATH_ODM_32BIT
135 #endif
136 
137 // ----------------------------------------------------------------------
138 // Class that provides Hidl instrumentation utilities.
139 struct HidlInstrumentor {
140     // Event that triggers the instrumentation. e.g. enter of an API call on
141     // the server/client side, exit of an API call on the server/client side
142     // etc.
143     enum InstrumentationEvent {
144         SERVER_API_ENTRY = 0,
145         SERVER_API_EXIT,
146         CLIENT_API_ENTRY,
147         CLIENT_API_EXIT,
148         SYNC_CALLBACK_ENTRY,
149         SYNC_CALLBACK_EXIT,
150         ASYNC_CALLBACK_ENTRY,
151         ASYNC_CALLBACK_EXIT,
152         PASSTHROUGH_ENTRY,
153         PASSTHROUGH_EXIT,
154     };
155 
156     // Signature of the instrumentation callback function.
157     using InstrumentationCallback = std::function<void(
158             const InstrumentationEvent event,
159             const char *package,
160             const char *version,
161             const char *interface,
162             const char *method,
163             std::vector<void *> *args)>;
164 
165     explicit HidlInstrumentor(
166             const std::string &package,
167             const std::string &insterface);
168     virtual ~HidlInstrumentor();
169 
170    public:
171     const std::vector<InstrumentationCallback>& getInstrumentationCallbacks() {
172         return mInstrumentationCallbacks;
173     }
174     bool isInstrumentationEnabled() { return mEnableInstrumentation; }
175 
176    protected:
177     // Set mEnableInstrumentation based on system property
178     // hal.instrumentation.enable, register/de-register instrumentation
179     // callbacks if mEnableInstrumentation is true/false.
180     void configureInstrumentation(bool log=true);
181     // Function that lookup and dynamically loads the hidl instrumentation
182     // libraries and registers the instrumentation callback functions.
183     //
184     // The instrumentation libraries should be stored under any of the following
185     // directories: HAL_LIBRARY_PATH_SYSTEM, HAL_LIBRARY_PATH_VNDK_SP,
186     // HAL_LIBRARY_PATH_VENDOR and HAL_LIBRARY_PATH_ODM.
187     // The name of instrumentation libraries should follow pattern:
188     // ^profilerPrefix(.*).profiler.so$
189     //
190     // Each instrumentation library is expected to implement the instrumentation
191     // function called HIDL_INSTRUMENTATION_FUNCTION.
192     //
193     // A no-op for user build.
194     void registerInstrumentationCallbacks(
195             std::vector<InstrumentationCallback> *instrumentationCallbacks);
196 
197     // Utility function to determine whether a give file is a instrumentation
198     // library (i.e. the file name follow the expected pattern).
199     bool isInstrumentationLib(const dirent *file);
200 
201     // A list of registered instrumentation callbacks.
202     std::vector<InstrumentationCallback> mInstrumentationCallbacks;
203     // Flag whether to enable instrumentation.
204     bool mEnableInstrumentation;
205     // Prefix to lookup the instrumentation libraries.
206     std::string mInstrumentationLibPackage;
207     // Used for dlsym to load the profiling method for given interface.
208     std::string mInterfaceName;
209 
210 };
211 
212 }  // namespace details
213 }  // namespace hardware
214 }  // namespace android
215 
216 #endif  // ANDROID_HIDL_INTERNAL_H
217