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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 #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" with '-' as a prefix.
48 // If "ro.vndk.version" is not set or set to "current", it returns empty string.
49 std::string getVndkVersionStr();
50 
51 // Explicitly invokes the parameterized element's destructor;
52 // intended to be used alongside the placement new operator.
53 template<typename T>
destructElement(T * element)54 void destructElement(T* element) {
55     if (element != nullptr) {
56         element->~T();
57     }
58 }
59 
60 // HIDL client/server code should *NOT* use this class.
61 //
62 // hidl_pointer wraps a pointer without taking ownership,
63 // and stores it in a union with a uint64_t. This ensures
64 // that we always have enough space to store a pointer,
65 // regardless of whether we're running in a 32-bit or 64-bit
66 // process.
67 template<typename T>
68 struct hidl_pointer {
hidl_pointerhidl_pointer69     hidl_pointer()
70         : _pad(0) {
71         static_assert(sizeof(*this) == 8, "wrong size");
72     }
hidl_pointerhidl_pointer73     hidl_pointer(T* ptr) : hidl_pointer() { mPointer = ptr; }
hidl_pointerhidl_pointer74     hidl_pointer(const hidl_pointer<T>& other) : hidl_pointer() { mPointer = other.mPointer; }
hidl_pointerhidl_pointer75     hidl_pointer(hidl_pointer<T>&& other) noexcept : hidl_pointer() { *this = std::move(other); }
76 
77     hidl_pointer &operator=(const hidl_pointer<T>& other) {
78         mPointer = other.mPointer;
79         return *this;
80     }
81     hidl_pointer& operator=(hidl_pointer<T>&& other) noexcept {
82         mPointer = other.mPointer;
83         other.mPointer = nullptr;
84         return *this;
85     }
86     hidl_pointer &operator=(T* ptr) {
87         mPointer = ptr;
88         return *this;
89     }
90 
91     operator T*() const {
92         return mPointer;
93     }
94     explicit operator void*() const { // requires explicit cast to avoid ambiguity
95         return mPointer;
96     }
97     T& operator*() const {
98         return *mPointer;
99     }
100     T* operator->() const {
101         return mPointer;
102     }
103     T &operator[](size_t index) {
104         return mPointer[index];
105     }
106     const T &operator[](size_t index) const {
107         return mPointer[index];
108     }
109 
110 private:
111     union {
112         T* mPointer;
113         uint64_t _pad;
114     };
115 };
116 
117 #define HAL_LIBRARY_PATH_SYSTEM_64BIT "/system/lib64/hw/"
118 #define HAL_LIBRARY_PATH_VNDK_SP_64BIT_FOR_VERSION "/system/lib64/vndk-sp%s/hw/"
119 #define HAL_LIBRARY_PATH_VENDOR_64BIT "/vendor/lib64/hw/"
120 #define HAL_LIBRARY_PATH_ODM_64BIT    "/odm/lib64/hw/"
121 #define HAL_LIBRARY_PATH_SYSTEM_32BIT "/system/lib/hw/"
122 #define HAL_LIBRARY_PATH_VNDK_SP_32BIT_FOR_VERSION "/system/lib/vndk-sp%s/hw/"
123 #define HAL_LIBRARY_PATH_VENDOR_32BIT "/vendor/lib/hw/"
124 #define HAL_LIBRARY_PATH_ODM_32BIT    "/odm/lib/hw/"
125 
126 #if defined(__LP64__)
127 #define HAL_LIBRARY_PATH_SYSTEM HAL_LIBRARY_PATH_SYSTEM_64BIT
128 #define HAL_LIBRARY_PATH_VNDK_SP_FOR_VERSION HAL_LIBRARY_PATH_VNDK_SP_64BIT_FOR_VERSION
129 #define HAL_LIBRARY_PATH_VENDOR HAL_LIBRARY_PATH_VENDOR_64BIT
130 #define HAL_LIBRARY_PATH_ODM    HAL_LIBRARY_PATH_ODM_64BIT
131 #else
132 #define HAL_LIBRARY_PATH_SYSTEM HAL_LIBRARY_PATH_SYSTEM_32BIT
133 #define HAL_LIBRARY_PATH_VNDK_SP_FOR_VERSION HAL_LIBRARY_PATH_VNDK_SP_32BIT_FOR_VERSION
134 #define HAL_LIBRARY_PATH_VENDOR HAL_LIBRARY_PATH_VENDOR_32BIT
135 #define HAL_LIBRARY_PATH_ODM    HAL_LIBRARY_PATH_ODM_32BIT
136 #endif
137 
138 // ----------------------------------------------------------------------
139 // Class that provides Hidl instrumentation utilities.
140 struct HidlInstrumentor {
141     // Event that triggers the instrumentation. e.g. enter of an API call on
142     // the server/client side, exit of an API call on the server/client side
143     // etc.
144     enum InstrumentationEvent {
145         SERVER_API_ENTRY = 0,
146         SERVER_API_EXIT,
147         CLIENT_API_ENTRY,
148         CLIENT_API_EXIT,
149         SYNC_CALLBACK_ENTRY,
150         SYNC_CALLBACK_EXIT,
151         ASYNC_CALLBACK_ENTRY,
152         ASYNC_CALLBACK_EXIT,
153         PASSTHROUGH_ENTRY,
154         PASSTHROUGH_EXIT,
155     };
156 
157     // Signature of the instrumentation callback function.
158     using InstrumentationCallback = std::function<void(
159             const InstrumentationEvent event,
160             const char *package,
161             const char *version,
162             const char *interface,
163             const char *method,
164             std::vector<void *> *args)>;
165 
166     explicit HidlInstrumentor(
167             const std::string &package,
168             const std::string &insterface);
169     virtual ~HidlInstrumentor();
170 
171    public:
getInstrumentationCallbacksHidlInstrumentor172     const std::vector<InstrumentationCallback>& getInstrumentationCallbacks() {
173         return mInstrumentationCallbacks;
174     }
isInstrumentationEnabledHidlInstrumentor175     bool isInstrumentationEnabled() { return mEnableInstrumentation; }
176 
177    protected:
178     // Set mEnableInstrumentation based on system property
179     // hal.instrumentation.enable, register/de-register instrumentation
180     // callbacks if mEnableInstrumentation is true/false.
181     void configureInstrumentation(bool log=true);
182     // Function that lookup and dynamically loads the hidl instrumentation
183     // libraries and registers the instrumentation callback functions.
184     //
185     // The instrumentation libraries should be stored under any of the following
186     // directories: HAL_LIBRARY_PATH_SYSTEM, HAL_LIBRARY_PATH_VNDK_SP,
187     // HAL_LIBRARY_PATH_VENDOR and HAL_LIBRARY_PATH_ODM.
188     // The name of instrumentation libraries should follow pattern:
189     // ^profilerPrefix(.*).profiler.so$
190     //
191     // Each instrumentation library is expected to implement the instrumentation
192     // function called HIDL_INSTRUMENTATION_FUNCTION.
193     //
194     // A no-op for user build.
195     void registerInstrumentationCallbacks(
196             std::vector<InstrumentationCallback> *instrumentationCallbacks);
197 
198     // Utility function to determine whether a give file is a instrumentation
199     // library (i.e. the file name follow the expected pattern).
200     bool isInstrumentationLib(const dirent *file);
201 
202     // A list of registered instrumentation callbacks.
203     std::vector<InstrumentationCallback> mInstrumentationCallbacks;
204     // Flag whether to enable instrumentation.
205     bool mEnableInstrumentation;
206     // Prefix to lookup the instrumentation libraries.
207     std::string mInstrumentationLibPackage;
208     // Used for dlsym to load the profiling method for given interface.
209     std::string mInterfaceName;
210 
211 };
212 
213 }  // namespace details
214 }  // namespace hardware
215 }  // namespace android
216 
217 #endif  // ANDROID_HIDL_INTERNAL_H
218