minipaxtar

minipaxtar is a small, freestanding C library for reading and writing POSIX PAX and USTAR tar archives. It is distributed under the MIT license.

It was designed as a safe, modern alternative to legacy lightweight tar libraries like microtar. Many existing micro-libraries lack defensive parsing, making them vulnerable to memory corruption or infinite loops when handling malformed input. minipaxtar provides strict bounds checking and robust error handling while keeping a minimal binary footprint.

📚 Read the Full Documentation

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Documentation Links

• ⏩ Overview & Getting Started:

  • Quickstart Guide
  • Reading Archives
  • Writing Archives
  • Extracting Files

• 📘 Guides & Configuration:

  • Error Handling
  • Status Codes Reference
  • Compile-Time Configuration & Defines

• ⚙️ API Reference:

  • Full API Group Reference
  • Full Structures API Reference
  • All Files API Reference

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Core Highlights

• Simple Integration: Available as both a standard .c/.h file pair and a single-header (stb-style) distribution.
• Very Lightweight: ~7 KB for read-only or write-only builds, ~14 KB for full functionality.
• Portable: Compiles cleanly across mainstream and minimal compilers, including GCC, Clang, MSVC, TCC, and chibicc.
• Broad C Support: Full compatibility from C89 through modern C drafts (like C2Y).
• Defensive Safety: Thorough input validation, safe integer arithmetic, and defensive memory lifetime tracking.
• 100% Freestanding: Zero standard library dependencies (MPTAR_NO_STD). Custom I/O and memory routines are passed explicitly through user configurations.

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Quick Integration

minipaxtar is designed to adapt to any C build system or project layout:

• CMake Integration: Fetch or include via add_subdirectory() or FetchContent.
• Manual Drop-in: Add minipaxtar.c and minipaxtar.h directly to your source tree.
• Single-Header Mode (stb-style): Include minipaxtar.h anywhere, and instantiate the implementation in exactly one C source file:

#define MINIPAXTAR_IMPLEMENTATION
#include "minipaxtar.h"

📑 View Full Integration Guide

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Memory & Resource Design

• Zero Implicit Allocation: minipaxtar never calls malloc or system allocators internally unless you explicitly supply allocation callbacks in reader/writer contexts.
• Clean Lifetime Control: Metadata allocations are isolated and cleared defensively (mptar_reader_free_metadata). Pointers are reset to NULL upon being freed, preventing double-free errors even during complex error-recovery paths.
• State Safety: Read and write contexts maintain clear offset tracking, avoiding out-of-bounds reads on truncated or corrupt archive headers.

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Comparison with microtar

minipaxtar was created as a modern, safe replacement for microtar, which has been unmaintained since 2017 and suffers from severe limits and security vulnerabilities.

Feature / Property	microtar	minipaxtar
Security Status	Vulnerable (CVE-2026-43623)	Defensive design, strict bounds checking
Standard Support	Basic V7 / Custom subset	USTAR, POSIX PAX, GNU binary extensions
Max Filename Length	100 bytes (No prefix field)	Unlimited via PAX extended headers
Max File Size	4 GB limit (unsigned 32-bit size)	Near-unlimited (Full 64-bit uint64_t support)
Standard Library Reliance	Heavily Coupled	Fully decoupled (MPTAR_NO_STD)
Zero-Copy Skipping	Requires seek/read operations	Instant offset and byte tracking
Write API Size	~5.2 KB	~6.3 KB

For a deep dive into code differences, API mechanics, and architectural breakdowns, see COMPARISON.md.

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License

This project is licensed under the MIT License. See the LICENSE file for details.

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📶 More in the Official Documentation