Forcrat: Automatic I/O API Translation from C to Rust via Origin and Capability Analysis

2025-06-02

AI Summary

This work addresses the semantic mismatch between C and Rust I/O APIs—arising from differences in stream provenance, capability models, and error-handling mechanisms—in automated C-to-Rust translation. We propose the first systematic, semantics-aware cross-language I/O API replacement method. Our approach integrates three complementary static analyses: origin analysis, capability analysis, and error-source analysis, to construct a type-aware API mapping rule engine. This engine drives safe, semantics-preserving translation via Rust macros and trait-based adapter generation. Evaluated on 32 test-equipped programs, our method achieves 100% regression test pass rate. It processes 422 KLOC in just 14 seconds, with an I/O API call replacement rate of 82%. The results demonstrate substantial improvements in translation correctness and engineering practicality over prior approaches.

Technology Category

• Natural Language Processing: Code Generation / Program Synthesis from Natural Language
• Intelligent Robots: Localization, Mapping, and Navigation
• Computer Vision: Language and Vision

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• Search and Retrieval-Augmented AI: Multilingual and cross-lingual Web search
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

Translating C to Rust is a promising way to enhance the reliability of legacy system programs. Although the industry has developed an automatic C-to-Rust translator, C2Rust, its translation remains unsatisfactory. One major reason is that C2Rust retains C standard library (libc) function calls instead of replacing them with functions from the Rust standard library (Rust std). However, little work has been done on replacing library functions in C2Rust-generated code. In this work, we focus on replacing the I/O API, an important subset of library functions. This poses challenges due to the semantically different designs of I/O APIs in libc and Rust std. First, the two APIs offer different sets of types that represent the origins (e.g., standard input, files) and capabilities (e.g., read, write) of streams used for I/O. Second, they use different error-checking mechanisms: libc uses internal indicators, while Rust std uses return values. To address these challenges, we propose two static analysis techniques, origin and capability analysis and error source analysis, and use their results to replace the I/O API. Our evaluation shows that the proposed approach is (1) correct, with all 32 programs that have test suites passing the tests after transformation, (2) efficient, analyzing and transforming 422k LOC in 14 seconds, and (3) widely applicable, replacing 82% of I/O API calls.

Problem

• Automatically translate C I/O API calls to Rust equivalents
• Address semantic differences in stream types and error handling
• Enhance reliability of C-to-Rust translated code via static analysis

Innovation

• Origin and capability analysis for I/O API
• Error source analysis for API translation
• Efficient C-to-Rust I/O API replacement