RandomDev

Simple Linux character device — integer generator based on constant-recursive sequences of bytes

Simple Usage

To use the RandomDev, follow these steps:

1. Clone the repository:

   git clone https://github.com/PolinaSavelyeva/RandomDev.git
   

2. Navigate to the RandomDev directory:

   cd RandomDev
   

3. Build the library using Make:

   make
   

4. Insert module and log kernel messages:

   sudo insmod mymodule.ko
   

   sudo dmesg
   

   or use:

   make test
   

   In kernel log you can see MAJOR number for your future character device.

5. Assign this MAJOR number to a new character device:

   sudo mknod /dev/randomdev c MAJOR 0
   

6. Make your device file writable and put data into it using printf:

   sudo chmod a+w /dev/randomdev
   

   printf "\K\A_1\...\A_K\X_1\...\X_K\C" > /dev/randomdev
   

   where,

   • K is an amount of coefficients to be provided in hexadecimal
   • A_i and X_i are hexadecimal coefficients, 1<=i<=K
   • C is a last polynomial hexadecimal coefficient

   example: K = 3, A_1 = 5, A_2 = 2, A_3 = 1, X_1 = 3, X_2 = 3, X_3 = 7, C = 4

   printf "\x03\x05\x02\x01\x03\x03\x07\x04" > /dev/randomdev
   

7. Read a sequence of random numbers using xxd:

   xxd /dev/randomdev
   

8. Remove device file:

   sudo rm /dev/randomdev
   

9. Remove module from kernel:

   sudo rmmod mymodule
   

Build Requirements

• Make utility
• C compiler

Tested on linux kernel version 5.15.0-107-generic.