android 使用uinput模擬輸入設備

在google remote中，android接收端接收socket發來的IR CODE，然後將IR CODE模擬出來發給系統處理，這就是google remote接收端的原理。

系統端怎樣模擬input event呢？
方法一：通過Instrumentation.sendKeyDownUpSync 實現，簡單使用但是問題在於sendKeyDownUpSync發出的event，無法運行到
interceptKeyBeforeDispatching，也就無法正常作用 HOME，VOL…
方法二：通過uinput橋接；原理是利用內核現有的uinput驅動，通過內核驅動uinput來發送input event，而且還容易使用kl,kcm 客制化；

經過比較方法二較優，下面就就給出方法二的測試代碼…

1、main函數，setup_uinput_device 完成設備的註冊，然後創建一個線程 VirtualInputDev_EventThread，該線程重復發出keycode；

  int main()
{


	printf("Enter process !!!! \n");

    stVirtualInputDevData *pKpdData = (stVirtualInputDevData*) malloc(sizeof(stVirtualInputDevData));
	  pKpdData->min_keycode = umin_keycode;
	  pKpdData->max_keycode = umax_keycode;
    if (setup_uinput_device(pKpdData) < 0) {
        printf("Unable to find uInput device\n");
        free(pKpdData);
        return -1;
    }

    pthread_attr_t attr;
    pthread_attr_init(&attr);
    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
    if (0 != pthread_create(&keypad_EventThreadId, &attr, VirtualInputDev_EventThread, (void *)0)) {
        printf("Create KeypadEventThread Failed!!\n");
        exit(1);
    }

    // Coverity server need set to ignore this.
    while (1) {
        usleep(1000000);  // sleep 1 second
    }

    free(pKpdData);
    pKpdData = 0;

    // Destroy the device
    ioctl(uinp_fd, UI_DEV_DESTROY);

    close(uinp_fd);
    return 0;
}

2、setup_uinput_device函數，完成設備註冊；可以看到是直接打開uinput節點，設置瞭虛擬設備的name，verdor，product，bustype，
最後通過ioctl(uinp_fd, UI_DEV_CREATE)註冊設備

   int setup_uinput_device(stVirtualInputDevData* mstVirtualInputDevData)
{
    struct uinput_user_dev uinp; // uInput device structure
    int i;

    // Open the input device
    uinp_fd = open("/dev/uinput", O_WRONLY | O_NDELAY);
    if (uinp_fd == 0) {
        printf("Unable to open /dev/uinput\n");
        return -1;
    }

    // Intialize the uInput device to NULL
    memset(&uinp, 0x00, sizeof(uinp));
    strncpy(uinp.name, "virtualinputdev", sizeof(uinp.name)-1);
    uinp.id.vendor = 0x1341;
    uinp.id.product = 0x0001;
    uinp.id.bustype = BUS_VIRTUAL;

    // Keyboard
    ioctl(uinp_fd, UI_SET_EVBIT, EV_KEY);
    for (i = mstVirtualInputDevData->min_keycode; i max_keycode; i++) {
        ioctl(uinp_fd, UI_SET_KEYBIT, i);
    }

    // Create input device into input sub-system
    if (write(uinp_fd, &uinp, sizeof(uinp)) != sizeof(uinp)) {
        printf("First write returned fail.\n");
        return -1;
    }

    if (ioctl(uinp_fd, UI_DEV_CREATE)) {
        printf("ioctl UI_DEV_CREATE returned fail.\n");
        return -1;
    }

    return 1;
}

3、線程 VirtualInputDev_EventThread，隻是重復發key，發key是通過write_event_to_device來完成的

   static void* VirtualInputDev_EventThread(void *driver_data)
{

    unsigned char u8Keycode,i=umin_keycode;

    while (1) {
        u8Keycode = 0xff;

        /* sleep an interval time */
        usleep(2000000);//sleep 5 s
        /* fill event to uinput device. */
        write_event_to_device(i++, 0);
		if(i==4){
		i = 0;
		}
		printf ("virtualinputdev thread ...\n");
		//i %= umax_keycode;
    }

    printf ("virtualinputdev thread died\n");
    pthread_exit(0);
    return 0;
}

4、write_event_to_device 寫event到uinput節點

  void write_event_to_device(unsigned char u8KeyCode, unsigned char u8Repeat)
{
    struct input_event event; // Input device structure
    struct timespec s;
    s.tv_nsec = 5000000L;
    s.tv_sec = 0;

    memset(&event, 0x00, sizeof(event));
    gettimeofday(&event.time, 0);
    event.type = EV_KEY;
    event.code = u8KeyCode;
    event.value = 1;
    write(uinp_fd, &event, sizeof(event));

    memset(&event, 0x00, sizeof(event));
    gettimeofday(&event.time, 0);
    event.type = EV_KEY;
    event.code = u8KeyCode;
    event.value = 0;
    write(uinp_fd, &event, sizeof(event));

    memset(&event, 0x00, sizeof(event));
    gettimeofday(&event.time, 0);
    event.type = EV_SYN;
    event.code = SYN_REPORT;
    event.value = 0;
    write(uinp_fd, &event, sizeof(event));
}