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