需要拦截HID键盘事件(然后阻止它们) [英] Need to intercept HID Keyboard events (and then block them)

问题描述

我有一个注册为HID设备的RFID USB设备(一个或多个USB键盘).

I've got a RFID USB device that registers as a HID device (A USB Keyboard more or less).

我正在寻找一种捕获此输入的方法，并在其击中普通键盘事件处理程序之前将其阻止/过滤(并将10位RFID代码输出到控制台).

I'm looking for a way to capture this input, and block/filter it before it hits the normal keyboard event handler (and outputs the 10 digit RFID code to the console).

我当然必须只捕获该设备，而不要留下真正的键盘输入(或将其传递).

I would of course have to exclusively capture just this device, and leave the real keyboard input alone (or pass it along).

我最初的想法是在UDEV中阻止该设备(因此usbhid/event/kbd内核模块未绑定到该设备)，并为此设备编写了自己的基本驱动程序-但我不知道从哪里开始，甚至可以解决问题.

My initial idea was to block the device in UDEV (So the usbhid/event/kbd kernel module didn't bind to it) and write my own basic driver for this device - but I don't know where to begin, or if that'll even work.

那将是很棒的(而且我不确定是否可以做这样的事情)-是我编写了一个事件过滤器模块，该模块可以与事件驱动程序串联，并捕获(然后过滤)适当的事件来自RFID单元的输入，但让其他所有东西都通过.我想这样的模块不需要太多的代码，并且会是最实用的.

What would be great (and I'm not sure if such a thing can be done) - is if I write a event-filter module that can sit in-line with the event driver and capture (then filter) the appropriate input from the RFID unit, but let everything else pass through. I imagine such a module wouldn't require much code, and would be the most practical.

帮助?

cat /proc/bus/input:
  I: Bus=0003 Vendor=0419 Product=0912 Version=0100
  N: Name="NewRoad Sem. NewRoad System PS2 Interface"
  P: Phys=usb-0000:00:1d.3-2/input0
  S: Sysfs=/devices/pci0000:00/0000:00:1d.3/usb5/5-2/5-2:1.0/input/input20
  U: Uniq=
  H: Handlers=sysrq kbd mouse0 event3
  B: PROP=0
  B: EV=120017
  B: KEY=70000 0 0 e080ffdf01cfffff fffffffffffffffe
  B: REL=103
  B: MSC=10
  B: LED=1f

更多信息:

lsusb -d 0419:0912 -v
Bus 005 Device 019: ID 0419:0912 Samsung Info. Systems America, Inc.
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0
  bDeviceProtocol         0
  bMaxPacketSize0         8
  idVendor           0x0419 Samsung Info. Systems America, Inc.
  idProduct          0x0912
  bcdDevice            0.01
  iManufacturer           1 NewRoad Sem.
  iProduct                2 NewRoad System PS2 Interface
  iSerial                 0
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           34
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          4
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      1 Keyboard
      iInterface              5
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.00
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength     119
         Report Descriptors:
           ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval              10
Device Status:     0x0000
  (Bus Powered)

推荐答案

所以我根据发现它确实满足了我的要求-即使我仍然会分享我的解决方案.

It does exactly what I require - just though I'd share my solution anyway.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <linux/input.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/select.h>
#include <sys/time.h>
#include <termios.h>
#include <signal.h>

int main(int argc, char* argv[])
{
    struct input_event ev[64];
    int fevdev = -1;
    int result = 0;
    int size = sizeof(struct input_event);
    int rd;
    int value;
    char name[256] = "Unknown";
    char *device = "/dev/input/event3";


    fevdev = open(device, O_RDONLY);
    if (fevdev == -1) {
        printf("Failed to open event device.\n");
        exit(1);
    }

    result = ioctl(fevdev, EVIOCGNAME(sizeof(name)), name);
    printf ("Reading From : %s (%s)\n", device, name);

    printf("Getting exclusive access: ");
    result = ioctl(fevdev, EVIOCGRAB, 1);
    printf("%s\n", (result == 0) ? "SUCCESS" : "FAILURE");

    while (1)
    {
        if ((rd = read(fevdev, ev, size * 64)) < size) {
            break;
        }

        value = ev[0].value;

        if (value != ' ' && ev[1].value == 1 && ev[1].type == 1) {
            printf ("Code[%d]\n", (ev[1].code));
        }
    }

    printf("Exiting.\n");
    result = ioctl(fevdev, EVIOCGRAB, 1);
    close(fevdev);
    return 0;
}

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