System Monitor

This is a simple tool to show running processes on a Linux machine. It is based on the starter code of a project in the Object Oriented Programming Course of Udacity C++ Nanodegree Program. The code in our repository has been reviewed by one of Udacity's mentors. The main inspiration of this project is clearly htop.

Installation

The System Monitor depends on ncurses. If it is not yet installed on your machine, please do so via

sudo apt install libncurses5-dev libncursesw5-dev

After that simply clone this repository and compile it via make build in the folder System-Monitor. For more details on the building process, see Make.

Usage

The System Monitor is opened via ./build/monitor (on a Linux machine). It shows the

• OS (e.g. Ubuntu)
• kernel
• accumulated CPU usage
• memory usage
• number of total and running processes
• up time
• a list of all running processes with CPU/memory usage etc. as in the screenshot below

Implementation

All the information of a Linux system is stored in the proc pseudo-filesystem usually mounted at /proc (see proc manual page). The heart of this project is a parser to read the relevant data from /proc(see linux_parser.cpp). The data of each process (e.g. CPU utilization or up time) are then stored in an instance of the class Process. Similarly, for each processor its utiliation is stored in a class instance of Processor (for simplicity we only work with the accumulated CPU utilization, hence only one class instance). All these system data are saved in a class instance of System. It is essentially composed of the processors and a vector of all processes.

Finally, printing the data of that class object to the terminal is done via ncurses which faciliatates text-based graphical output to the terminal.

On the starter code

As alluded to above, the skeleton of this project was provided by Udacity. Its main part was the output via ncurses and a small fraction of the linux parser yielding the following