About yes-mod

Yes-mod is a linux kernel module that implements a character device file providing fixed string repatedly like yes command. The device file is named /dev/yes.

Install

1. Build the kernel module.

   $ make
   

2. Load the built module.

   $ sudo insmod yes.ko
   

Usage

Reading /dev/yes provides repated mesage. The default string is y

$ head /dev/yes
y
y
y
y
y
y
y
y
y
y

Writing to /dev/yes changes the read string. NL will be appended if the last character is not NL.

$ echo no > /dev/yes
$ head /dev/yes
no
no
no
no
no
no
no
no
no
no

Supplement

To install the module to the system

You can install the module to the system and load from there.

$ sudo make install
$ sudo depmod
$ modprobe yes

I cannot open /dev/yes due to permission error

Depending to the system settings, /dev/yes cannot be opend except by root user. To grant permission for other user to open the device file, you have to create appropriate udev rules. There is a sample udev configuration file 99-yes.rules in the source directory. Putting that file into /etc/udev/rules.d grant permission for all users to read/write /dev/yes from next module loading.