Explanation of the Code

Overview

This project consists of a user-space application and a Linux kernel module. The goal is to read and display system information such as the version, CPU details, memory usage, and uptime through a /proc file interface.

User-Space Application

1. userinput() Function:

   • This function handles user input to determine which information the user wants to retrieve: version, CPU details, memory usage, time, or all available data.
   • Based on the user's selection, the function sets the appropriate row range and calls the information() function to fetch the required data.

2. information() Function:

   • This function reads the data from the /proc/my_info file.
   • It filters the data based on the user's input to display only the requested information or all the information if requested.
   • The data is read line by line, and relevant lines are printed to the console.

Kernel Module

1. Kernel Module Overview:

   • The kernel module creates a /proc entry called my_info. When this file is accessed, it provides system information, including the Linux version, CPU specifications, memory usage, and uptime.

2. Sequence File Operations:

   • The kernel module uses a sequence file interface to handle the reading of system information.
   • my_seq_start(), my_seq_next(), my_seq_stop(): These functions manage the start, iteration, and stop of reading data in sequence.
   • my_seq_show(): This function is called for each step of the sequence and is responsible for printing the system information to the /proc file.

3. System Information Gathering:

   • The module gathers various system metrics:
     • Version: Kernel and system version information.
     • CPU: Details about the CPU cores, such as processor ID, core ID, and cache size.
     • Memory: Information about total memory, free memory, buffers, active/inactive memory, and more.
     • Time: Uptime and idle time of the system.

4. my_open() Function:

   • This function is called when the /proc/my_info file is opened. It sets up the sequence operations to handle the data reading.

5. Module Initialization and Cleanup:

   • The module creates the /proc/my_info entry during initialization and removes it during cleanup.

6. Module License:

   • The module is licensed under the GPL, ensuring that it is open-source and freely distributable.

Summary

This project demonstrates the integration of a user-space application with a custom Linux kernel module to provide system information through the /proc filesystem. The user-space application interacts with the kernel module by reading from a /proc entry, allowing users to request specific system metrics interactively.