microseh 1.0.3

Structured Exception Handling (SEH) for Rust
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72

<h1 align="center">MicroSEH 🔴</h1>

<div align="center">
  <a href="https://crates.io/crates/microseh"><img src="https://img.shields.io/crates/v/microseh.svg"/></a>
  <a href="https://github.com/sonodima/microseh/actions?workflow=CI">
    <img src="https://github.com/sonodima/microseh/workflows/CI/badge.svg"/>
  </a>
  <a href="https://crates.io/crates/microseh"><img src="https://img.shields.io/crates/d/microseh?color=pink"/></a>
  <img src="https://img.shields.io/badge/license-MIT-blue.svg"/>
</div>

<br>

> MicroSEH is a tiny library that implements Structured Exception Handling (SEH) in Rust and can catch
> and handle hardware exceptions.

## Why?


Hardware exceptions are a very powerful tool for specific use cases. One such use case is to
detect and handle illegal instructions at runtime.

## Implementation


It turns out that implementing SEH in pure Rust has its own issues (as seen in
[this article from NAMAZSO](https://engineering.zeroitlab.com/2022/03/13/rust-seh))

This library uses a different, simpler approach, which is to use a `C` stub that calls back into Rust, wrapping
the call in a `__try __except` block.

## Usage


Add this to your `Cargo.toml`:

```toml
[dependencies]
microseh = "1.0"
```

**Minimal Example:** Dereference an invalid pointer without crashing the program, and return the handled exception.

```rust
fn guarded() -> Result<(), Box<dyn Error>> {
    
    
    microseh::try_seh(|| unsafe {
        // Read from an unallocated memory region. (we create an aligned not-null
        // pointer to skip the checks in read_volatile that would raise a panic)
        core::ptr::read_volatile(core::mem::align_of::<i32>() as *const i32);
    })?;
}
```

**Accessing Exception Data:** You can obtain the address and register dump of an exception.

```rust
if let Err(ex) = microseh::try_seh(|| unsafe {
    // *questionable life choices go here*
}) {
    println!("address: {:x}", ex.address());
    println!("rax: {:x}", ex.registers().rax());
}
```

_For additional examples and practical use cases, please visit the [examples](./examples) directory!_

## Portability


SEH is an extension to the C language developed by Microsoft, and it is exclusively available
on Windows when using Microsoft Visual C++ (MSVC).

MicroSEH is compatible with and has been tested on Windows platforms with the following
architectures: **x86**, **x86_64** and **aarch64**.