disk_eraser

A simple command-line utility to securely overwrite hard drives on Unix-like systems, making data recovery infeasible.

Platform Support

This tool is designed for Unix-like operating systems:

• macOS (tested on macOS 14+)
• Linux (tested on modern distributions)

Note: Windows is not supported. This is a tool for serious Unix systems, not for gaming consoles or office workstations.

Overview

disk_eraser writes zeros to an entire disk device, effectively wiping all data. It includes safety checks to prevent accidental data loss, real-time progress monitoring, and proper signal handling.

Features

• Double confirmation before operations
• System disk detection and protection
• Real-time progress display (percentage, speed, ETA)
• Raw device access for optimal performance
• Signal handling (CTRL+C) for clean interruption
• Operation logging with timestamps

Requirements

• Unix-like system (macOS or Linux)
• Root privileges
• CMake 4.0+
• Standard C11 compiler

Building

cmake -B build -S .
cmake --build build

The executable will be in build/disk_eraser.

Usage

sudo ./disk_eraser

The program will:

1. List available disks
2. Prompt for disk selection
3. Display disk information
4. Request double confirmation
5. Unmount the disk
6. Overwrite the entire disk with zeros
7. Show final statistics

Example Session

====================================
    Disk Erase Tool v1.0
====================================

Available disks:
  /dev/disk0 (internal, physical):
     0: GUID_partition_scheme  *500.3 GB   disk0
  /dev/disk2 (external, physical):
     0: GUID_partition_scheme  *2.0 TB     disk2

Enter disk to erase (e.g., disk2 or /dev/disk2): disk2

!!! WARNING !!!
================
This will permanently erase ALL data on:
  Device: /dev/disk2
  Size: 2.0 TB

This operation CANNOT be undone!
ALL data will be PERMANENTLY lost!

Type 'YES' to continue: YES

Type 'disk2' to confirm: disk2

Unmounting disk...
Opening raw device: /dev/rdisk2

Starting secure erase...

[========================================] 100.0% | 2.0 TB / 2.0 TB
Speed: 125.3 MB/s | Elapsed: 4h 32m | ETA: 0s

Operation completed successfully!

Architecture

disk_eraser/
├── main.c          # Entry point and main flow
├── disk_ops.c/h    # Disk operations (list, verify, wipe)
├── progress.c/h    # Progress tracking and display
└── utils.c/h       # Utility functions (formatting, logging)

Components

disk_ops: Low-level disk operations

• Device listing
• System disk detection
• Device unmounting
• Raw device access
• Write loop with error handling

progress: Progress tracking

• Completion percentage calculation
• Real-time write speed monitoring
• ETA estimation
• Final statistics

utils: Support functions

• Byte formatting (B, KB, MB, GB, TB)
• Time formatting
• User confirmation prompts
• File logging

Safety Mechanisms

1. Root privilege verification
2. System disk protection
3. Double confirmation requirement
4. Device path validation
5. Clean signal handling (SIGINT, SIGTERM)
6. Comprehensive logging to disk_erase.log

Technical Details

• Buffer size: 1 MB aligned to 4096 bytes
• Write pattern: Single pass of zeros (0x00)
• Sync mode: O_SYNC flag ensures data reaches disk
• macOS: Uses /dev/rdiskX for raw access, diskutil for listing
• Linux: Uses /dev/sdX, standard Unix tools for listing

Platform Differences

macOS

• Raw devices: /dev/rdiskX
• Disk listing: diskutil list
• Disk info: diskutil info
• Block device ioctl: DKIOCGETBLOCKSIZE, DKIOCGETBLOCKCOUNT

Linux

• Raw devices: /dev/sdX (no separate raw device)
• Disk listing: Parse /proc/partitions or use lsblk
• Block device ioctl: BLKGETSIZE64

Limitations

• Requires root privileges
• Single-pass overwrite (sufficient for modern drives)
• Cannot be used on mounted root filesystem

Logging

All operations are logged to disk_erase.log:

[2025-11-17 10:00:00] Program started
[2025-11-17 10:00:15] Selected disk: /dev/disk2
[2025-11-17 10:00:20] User confirmed operation
[2025-11-17 10:00:25] Starting wipe operation - size: 2000398934016 bytes
[2025-11-17 14:32:10] Operation completed successfully

Security Note

Single-pass zero overwriting is considered sufficient for modern hard drives and SSDs. Multiple-pass overwriting (Gutmann method, DoD 5220.22-M) is largely obsolete due to increased storage density and wear-leveling in SSDs.

Warning

This program permanently destroys data. Use with extreme caution.

• Always verify the target disk twice
• Backup important data before use
• Test on a sacrificial USB drive first
• Do not interrupt during operation

License

MIT License

Disclaimer

This software is provided "as is", without warranty of any kind. The author is not responsible for data loss or damage caused by use of this program. Use at your own risk.