1 #ifndef ANDROID_DVR_EVDEV_INJECTOR_H
2 #define ANDROID_DVR_EVDEV_INJECTOR_H
3 
4 #include <android-base/unique_fd.h>
5 #include <linux/uinput.h>
6 #include <utils/String8.h>
7 
8 #include <cstdint>
9 #include <memory>
10 #include <unordered_set>
11 
12 namespace android {
13 namespace dvr {
14 
15 // Simulated evdev input device.
16 //
17 class EvdevInjector {
18  public:
19   // EvdevInjector-specific error codes are negative integers; other non-zero
20   // values returned from public routines are |errno| codes from underlying I/O.
21   // EvdevInjector maintains a 'sticky' error state, similar to |errno|, so that
22   // a caller can perform a sequence of operations and check for errors at the
23   // end using |GetError()|. In general, the first such error will be recorded
24   // and will suppress effects of further device operations until |ResetError()|
25   // is called.
26   //
27   enum : int {
28     ERROR_DEVICE_NAME = -1,     // Invalid device name.
29     ERROR_PROPERTY_RANGE = -2,  // |INPUT_PROP_*| code out of range.
30     ERROR_KEY_RANGE = -3,       // |KEY_*|/|BTN_*| code out of range.
31     ERROR_ABS_RANGE = -4,       // |ABS_*| code out of range.
32     ERROR_SEQUENCING = -5,      // Configure/Send out of order.
33   };
34 
35   // Key event |value| is not defined in <linux/input.h>.
36   enum : int32_t { KEY_RELEASE = 0, KEY_PRESS = 1, KEY_REPEAT = 2 };
37 
38   // UInput provides a shim to intercept /dev/uinput operations
39   // just above the system call level, for testing.
40   //
41   class UInput {
42    public:
UInput()43     UInput() {}
~UInput()44     virtual ~UInput() {}
45     virtual int Open();
46     virtual int Close();
47     virtual int Write(const void* buf, size_t count);
48     virtual int IoctlVoid(int request);
49     virtual int IoctlSetInt(int request, int value);
50 
51    private:
52     base::unique_fd fd_;
53   };
54 
EvdevInjector()55   EvdevInjector() {}
~EvdevInjector()56   ~EvdevInjector() { Close(); }
57   void Close();
58 
GetError()59   int GetError() const { return error_; }
ResetError()60   void ResetError() { error_ = 0; }
61 
62   // Configuration must be performed before sending any events.
63   // |ConfigureBegin()| must be called first, and |ConfigureEnd()| last,
64   // with zero or more other |Configure...()| calls in between in any order.
65 
66   // Configure the basic evdev device properties; must be called first.
67   int ConfigureBegin(const char* device_name, int16_t bustype, int16_t vendor,
68                      int16_t product, int16_t version);
69 
70   // Configure an optional input device property.
71   // @param property  One of the |INPUT_PROP_*| constants from <linux/input.h>.
72   int ConfigureInputProperty(int property);
73 
74   // Configure an input key.
75   // @param key One of the |KEY_*| or |BTN_*| constants from <linux/input.h>.
76   int ConfigureKey(uint16_t key);
77 
78   // Configure an absolute axis.
79   // @param abs_type One of the |KEY_*| or |BTN_*| constants from
80   // <linux/input.h>.
81   int ConfigureAbs(uint16_t abs_type, int32_t min, int32_t max, int32_t fuzz,
82                    int32_t flat);
83 
84   // Configure the number of multitouch slots.
85   int ConfigureAbsSlots(int slots);
86 
87   // Configure multitouch coordinate range.
88   int ConfigureMultiTouchXY(int32_t x0, int32_t y0, int32_t x1, int32_t y1);
89 
90   // Complete configuration and create the input device.
91   int ConfigureEnd();
92 
93   // Send various events.
94   //
95   int Send(uint16_t type, uint16_t code, int32_t value);
96   int SendSynReport();
97   int SendKey(uint16_t code, int32_t value);
98   int SendAbs(uint16_t code, int32_t value);
99   int SendMultiTouchSlot(int32_t slot);
100   int SendMultiTouchXY(int32_t slot, int32_t id, int32_t x, int32_t y);
101   int SendMultiTouchLift(int32_t slot);
102 
103   void dumpInternal(String8& result);
104 
105  protected:
106   // Must be called only between construction and ConfigureBegin().
SetUInputForTesting(UInput * uinput)107   inline void SetUInputForTesting(UInput* uinput) { uinput_ = uinput; }
108   // Caller must not retain pointer longer than EvdevInjector.
GetUiDevForTesting()109   inline const uinput_user_dev* GetUiDevForTesting() const { return &uidev_; }
110 
111  private:
112   // Phase to enforce that configuration is complete before events are sent.
113   enum class State { NEW, CONFIGURING, READY, CLOSED };
114 
115   // Sets |error_| if it is not already set; returns |code|.
116   int Error(int code);
117 
118   // Returns a nonzero error if the injector is not in the required |state|.
119   int RequireState(State state);
120 
121   // Configures an event type if necessary.
122   // @param type One of the |EV_*| constants from <linux/input.h>.
123   int EnableEventType(uint16_t type);
124 
125   // Active pointer to owned or testing UInput.
126   UInput* uinput_ = nullptr;
127   std::unique_ptr<UInput> owned_uinput_;
128 
129   State state_ = State::NEW;
130   int error_ = 0;
131   uinput_user_dev uidev_;
132   std::unordered_set<uint16_t> enabled_event_types_;
133   int32_t latest_slot_ = -1;
134 
135   EvdevInjector(const EvdevInjector&) = delete;
136   void operator=(const EvdevInjector&) = delete;
137 };
138 
139 }  // namespace dvr
140 }  // namespace android
141 
142 #endif  // ANDROID_DVR_EVDEV_INJECTOR_H
143