https://github.com/geofft/redhook

Dynamic function call interposition / hooking (LD_PRELOAD) for Rust
https://github.com/geofft/redhook

Last synced: 6 days ago
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Dynamic function call interposition / hooking (LD_PRELOAD) for Rust

• Host: GitHub
• URL: https://github.com/geofft/redhook
• Owner: geofft
• License: bsd-2-clause
• Created: 2015-04-25T18:47:57.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2022-10-04T18:52:26.000Z (about 2 years ago)
• Last Synced: 2024-03-14T17:31:52.319Z (8 months ago)
• Language: Rust
• Size: 20.5 KB
• Stars: 167
• Watchers: 4
• Forks: 17
• Open Issues: 13
• Metadata Files:
  • Readme: README.md
  • License: COPYING

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README

        
redhook

=======

redhook is a helper crate for writing interposition libraries

(`LD_PRELOAD`, `DYLD_INSERT_LIBRARIES`, etc.) in Rust.

To use redhook, edit your `Cargo.toml` to add redhook as a dependency

and configure your library to build as a `dylib`:

```toml

[dependencies]

redhook = "2.0"

[lib]

name = "mylib"

crate_type = ["dylib"]

```

Then use the `hook!` macro to declare the function you want to hook, and

the name you want to give to your hook function:

```rust

redhook::hook! {

    unsafe fn existing_function(x: i32) -> i32 => my_function {

        42

    }

}

```

To access the underlying function, use `redhook::real!(existing_function)`.

Build your library as usual, find the resulting `.so` file (or `.dylib`,

for macOS) inside the `target` directory, and set the `LD_PRELOAD` (or

`DYLD_INSERT_LIBRARIES`) environment variable to that.

(You can also use redhook without Cargo, with `rustc --crate-type=dylib`.)

There are a few [examples](examples) included, as separate crates:

```

geofft@cactuar:~/src/rust/redhook/examples/readlinkspy$ cargo build

   Compiling redhook v0.0.1 (file:///home/geofft/src/rust/redhook/examples/readlinkspy)

   Compiling redhook_ex_readlinkspy v0.0.1 (file:///home/geofft/src/rust/redhook/examples/readlinkspy)

geofft@cactuar:~/src/rust/redhook/examples/readlinkspy$ LD_PRELOAD=target/debug/libreadlinkspy.so ls -l /bin/sh

readlink("/bin/sh")

lrwxrwxrwx 1 root root 4 Feb 19  2014 /bin/sh -> dash

```

```

geofft@cactuar:~/src/rust/redhook/examples/fakeroot$ cargo build

geofft@cactuar:~/src/rust/redhook/examples/fakeroot$ LD_PRELOAD=target/debug/libfakeroot.so id

uid=0(root) gid=1001(geofft) euid=1001(geofft) groups=1001(geofft),27(sudo),111(sbuild)

```

redhook currently supports building interposition libraries for

`LD_PRELOAD` on glibc (GNU/Linux) and `DYLD_INSERT_LIBRARIES` on Apple's

libc (macOS) from the same source code. If you're interested in

support for other platforms, please file an issue or pull request.

redhook is named after the [Red Hook](http://en.wikipedia.org/wiki/Red_Hook,_Brooklyn)

neighborhood in Brooklyn, New York. Portions of the implementation

borrow heavily from concepts in @Kimundi's

[`lazy_static!`](https://github.com/Kimundi/lazy-static.rs) macro.

redhook is free software, available under the terms of the

[2-clause BSD license](COPYING).

Minimum supported Rust version: **1.32**

[![Build Status](https://travis-ci.org/geofft/redhook.svg?branch=master)](https://travis-ci.org/geofft/redhook)