87 lines
2.4 KiB
Markdown
87 lines
2.4 KiB
Markdown
---
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name: unsafe-checker
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description: "CRITICAL: Use for unsafe Rust code review and FFI. Triggers on: unsafe, raw pointer, FFI, extern, transmute, *mut, *const, union, #[repr(C)], libc, std::ffi, MaybeUninit, NonNull, SAFETY comment, soundness, undefined behavior, UB, safe wrapper, memory layout, bindgen, cbindgen, CString, CStr, 安全抽象, 裸指针, 外部函数接口, 内存布局, 不安全代码, FFI 绑定, 未定义行为"
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globs: ["**/*.rs"]
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allowed-tools: ["Read", "Grep", "Glob"]
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---
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Display the following ASCII art exactly as shown. Do not modify spaces or line breaks:
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```text
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⚠️ **Unsafe Rust Checker Loaded**
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* ^ *
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/◉\_~^~_/◉\
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⚡/ o \⚡
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'_ _'
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/ '-----' \
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```
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---
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# Unsafe Rust Checker
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## When Unsafe is Valid
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| Use Case | Example |
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|----------|---------|
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| FFI | Calling C functions |
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| Low-level abstractions | Implementing `Vec`, `Arc` |
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| Performance | Measured bottleneck with safe alternative too slow |
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**NOT valid:** Escaping borrow checker without understanding why.
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## Required Documentation
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```rust
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// SAFETY: <why this is safe>
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unsafe { ... }
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/// # Safety
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/// <caller requirements>
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pub unsafe fn dangerous() { ... }
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```
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## Quick Reference
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| Operation | Safety Requirements |
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|-----------|---------------------|
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| `*ptr` deref | Valid, aligned, initialized |
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| `&*ptr` | + No aliasing violations |
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| `transmute` | Same size, valid bit pattern |
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| `extern "C"` | Correct signature, ABI |
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| `static mut` | Synchronization guaranteed |
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| `impl Send/Sync` | Actually thread-safe |
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## Common Errors
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| Error | Fix |
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|-------|-----|
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| Null pointer deref | Check for null before deref |
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| Use after free | Ensure lifetime validity |
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| Data race | Add proper synchronization |
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| Alignment violation | Use `#[repr(C)]`, check alignment |
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| Invalid bit pattern | Use `MaybeUninit` |
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| Missing SAFETY comment | Add `// SAFETY:` |
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## Deprecated → Better
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| Deprecated | Use Instead |
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|------------|-------------|
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| `mem::uninitialized()` | `MaybeUninit<T>` |
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| `mem::zeroed()` for refs | `MaybeUninit<T>` |
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| Raw pointer arithmetic | `NonNull<T>`, `ptr::add` |
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| `CString::new().unwrap().as_ptr()` | Store `CString` first |
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| `static mut` | `AtomicT` or `Mutex` |
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| Manual extern | `bindgen` |
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## FFI Crates
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| Direction | Crate |
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|-----------|-------|
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| C → Rust | bindgen |
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| Rust → C | cbindgen |
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| Python | PyO3 |
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| Node.js | napi-rs |
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Claude knows unsafe Rust. Focus on SAFETY comments and soundness.
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