wrun

wrun is a utility written in C to identify processes that are using a specific TCP port and, optionally, terminate those processes.

Usage

Show help:

wrun --help

Operate on a TCP port:

# Query the process using port 8080
wrun -p 8080

# Terminate the process associated with the port
wrun -k -p 8080

Note: The -p/--port parameter is required.

How It Works: Process Discovery Flow

flowchart TD
    A[Input: Port Number] --> B[Query /proc/net/tcp for IPv4 sockets]
    A --> C[Query /proc/net/tcp6 for IPv6 sockets]
    
    B --> D[Filter by port and LISTEN status 10]
    C --> E[Filter by port and LISTEN status 10]
    
    D --> F[Extract socket inodes]
    E --> G[Extract socket inodes]
    
    F --> H[Search /proc/pid/fd for socket:inode]
    G --> H
    
    H --> I[Match found?]
    I -->|Yes| J[Read /proc/pid/comm for process name]
    I -->|No| K[Continue searching]
    
    J --> L[Output: PID process_name port protocol]
    K --> M[More PIDs to check?]
    M -->|Yes| H
    M -->|No| N[Done]
    
    L --> N

Loading

The algorithm uses Linux /proc filesystem to map sockets to processes through inode numbers.

Requirements

• Any C compiler
• make utility
• Linux system

Compile and Install

Compile:

cd wrun
make

Install:

make install

# Uninstall
make uninstall

Purpose

This project was developed to:

• Learn C from scratch
• Learn how to use dynamic memory management in C
• Learn how processes work in Linux

Contributing

Contributions are welcome. If you have a suggestion that would make this better, please fork the repo and create a pull request or you can also simply open an issue.