linux查找刷卡器输入设备

说明

由于每次插入刷卡器之后，控制句柄会发生改变。

例如这次是/dev/input/event1,下次是/dev/input/event0。面对会有多个event，必须写个查找程序。

解决方法

linux系统里面的/proc/bus/input/devices文件存储了输入设备的信息，可以通过读取该文件判断输入设备。该文件信息如下：

[email protected]:~$ cat /proc/bus/input/devices 
I: Bus=0019 Vendor=0000 Product=0001 Version=0000
N: Name="Power Button"
P: Phys=PNP0C0C/button/input0
S: Sysfs=/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0C:00/input/input0
U: Uniq=
H: Handlers=kbd event0 
B: PROP=0
B: EV=3
B: KEY=10000000000000 0

I: Bus=0019 Vendor=0000 Product=0001 Version=0000
N: Name="Power Button"
P: Phys=LNXPWRBN/button/input0
S: Sysfs=/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1
U: Uniq=
H: Handlers=kbd event1 
B: PROP=0
B: EV=3
B: KEY=10000000000000 0

I: Bus=0003 Vendor=413c Product=2106 Version=0110
N: Name="DELL Dell QuietKey Keyboard"
P: Phys=usb-0000:00:1d.1-1/input0
S: Sysfs=/devices/pci0000:00/0000:00:1d.1/usb7/7-1/7-1:1.0/0003:413C:2106.0001/input/input5
U: Uniq=
H: Handlers=sysrq kbd event2 leds 
B: PROP=0
B: EV=120013
B: KEY=1000000000007 ff9f207ac14057ff febeffdfffefffff fffffffffffffffe
B: MSC=10
B: LED=7

I: Bus=0003 Vendor=093a Product=2510 Version=0111
N: Name="PixArt USB Optical Mouse"
P: Phys=usb-0000:00:1d.1-2/input0
S: Sysfs=/devices/pci0000:00/0000:00:1d.1/usb7/7-2/7-2:1.0/0003:093A:2510.0002/input/input6
U: Uniq=
H: Handlers=mouse0 event3 
B: PROP=0
B: EV=17
B: KEY=70000 0 0 0 0
B: REL=103
B: MSC=10

I: Bus=0003 Vendor=ffff Product=0035 Version=0110
N: Name="Sycreader RFID Technology Co., Ltd SYC ID&IC USB Reader"
P: Phys=usb-0000:00:1d.2-1/input0
S: Sysfs=/devices/pci0000:00/0000:00:1d.2/usb8/8-1/8-1:1.0/0003:FFFF:0035.0003/input/input7
U: Uniq=08FF20140315
H: Handlers=sysrq kbd event4 leds 
B: PROP=0
B: EV=120013
B: KEY=e080ffdf01cfffff fffffffffffffffe
B: MSC=10
B: LED=1f

I: Bus=0003 Vendor=e806 Product=6001 Version=0040
N: Name="USB 2.0 Camera"
P: Phys=usb-0000:00:1d.7-6/button
S: Sysfs=/devices/pci0000:00/0000:00:1d.7/usb2/2-6/2-6:1.0/input/input8
U: Uniq=
H: Handlers=kbd event5 
B: PROP=0
B: EV=3
B: KEY=100000 0 0 0

I: Bus=0000 Vendor=0000 Product=0000 Version=0000
N: Name="HDA Intel Front Mic"
P: Phys=ALSA
S: Sysfs=/devices/pci0000:00/0000:00:1b.0/sound/card0/input9
U: Uniq=
H: Handlers=event6 
B: PROP=0
B: EV=21
B: SW=10

I: Bus=0000 Vendor=0000 Product=0000 Version=0000
N: Name="HDA Intel Rear Mic"
P: Phys=ALSA
S: Sysfs=/devices/pci0000:00/0000:00:1b.0/sound/card0/input10
U: Uniq=
H: Handlers=event7 
B: PROP=0
B: EV=21
B: SW=10

I: Bus=0000 Vendor=0000 Product=0000 Version=0000
N: Name="HDA Intel Line"
P: Phys=ALSA
S: Sysfs=/devices/pci0000:00/0000:00:1b.0/sound/card0/input11
U: Uniq=
H: Handlers=event8 
B: PROP=0
B: EV=21
B: SW=2000

I: Bus=0000 Vendor=0000 Product=0000 Version=0000
N: Name="HDA Intel Line Out"
P: Phys=ALSA
S: Sysfs=/devices/pci0000:00/0000:00:1b.0/sound/card0/input12
U: Uniq=
H: Handlers=event9 
B: PROP=0
B: EV=21
B: SW=40

I: Bus=0000 Vendor=0000 Product=0000 Version=0000
N: Name="HDA Intel Front Headphone"
P: Phys=ALSA
S: Sysfs=/devices/pci0000:00/0000:00:1b.0/sound/card0/input13
U: Uniq=
H: Handlers=event10 
B: PROP=0
B: EV=21
B: SW=4

可以看到以上信息中有"Sycreader RFID Technology Co., Ltd SYC ID&IC USB Reader"关键字，通过该关键字可以判断刷卡器的控制句柄为event4

程序说明

代码段查看链接