plnk

plnk is a simple command-line tool for blocking and unblocking specific domains on Unix-based systems by modifying the system's /etc/hosts file. It redirects blocked domains to 127.0.0.1 and provides easy backup and restoration functionality.

Features

• Block a list of domains by redirecting them to 127.0.0.1
• Automatically backs up your /etc/hosts file before making changes
• Restore the original /etc/hosts file with a single command
• Configurable through a TOML configuration file
• Built-in validation to prevent duplicate blocking
• Root privilege checking for security

Installation

Option 1: Install directly from Git (Recommended)

cargo install --git https://github.com/mtognela/plnk.git
# symbolic link it to make it system available
sudo ln -sf /home/"$USER"/.cargo/bin/plnk /usr/local/bin/plnk

This will install plnk to your Cargo bin directory (usually ~/.cargo/bin/), which should be in your PATH.

Configuration

plnk reads its configuration fryom a TOML file under this path: /etc/plnk/config.toml

Setting up the config file:

Create a config.toml file under this path: /etc/plnk/config.toml:

blocked_domains = [
    "facebook.com",
    "www.facebook.com",
    "twitter.com",
    "www.twitter.com",
    "instagram.com",
    "www.instagram.com",
    "youtube.com",
    "www.youtube.com"
]

Symbolic link it to /home/$USER/.config/plnk/config.toml:

sudo ln -s /etc/plnk/config.toml /home/$USER/.config/plnk/config.toml 

Usage

All operations require root privileges:

Block domains:

sudo plnk

Unblock domains (restore original hosts file):

sudo plnk u

Show help:

plnk h
# or
plnk help

How it works

1. Blocking: When you run plnk without arguments, it:

   • Checks if you have root privileges
   • Loads the configuration from the file specified at /etc/plnk/config.toml
   • Verifies that domains aren't already blocked
   • Creates a backup of /etc/hosts at /etc/hosts.backup
   • Appends the blocked domains to /etc/hosts with the marker # plnk url blocking

2. Unblocking: When you run plnk u, it:

   • Restores the original /etc/hosts file from the backup
   • Removes the backup file

Error Handling

The tool includes comprehensive error handling for:

• Missing or invalid configuration files
• Permission issues (not running as root)
• File I/O errors
• Invalid domain entries (empty domains)
• Attempting to block already blocked domains

Requirements

• Rust (for building)
• Unix-based system (Linux, macOS, etc.)
• Root privileges for execution
• TOML configuration file

Dependencies

• serde - for configuration deserialization
• toml - for parsing TOML configuration files

Notes

• The program creates a backup at /etc/hosts.backup before making any changes
• If domains are already blocked, the program will exit with an error message
• Restoring will completely replace the current /etc/hosts with the backup
• Make sure to include both domain.com and www.domain.com variants in your config for complete blocking

Author

Mattia Tognela <tognelamattia at protonmail dot com>

License

MIT License.

Repository

https://github.com/mtognela/plnk