Wasi Extended Library

Copyright (c) 2022-2023 Antmicro

This repository contains a custom API for syscalls that are not yet implemented in wasi. In order to keep compiled binaries compatible with other runtimes, these syscalls are not explicitly added to the WASI standard. Instead, they are redirected from the path_readlink function.

Build

To build Rust and C libs you need wasi-sdk. For installation instructions, refer to the official WASI SDK installation guide. After completing the installation steps, set the WASI_SDK_PATH environment variable:

export WASI_SDK_PATH="/path/to/wasi-sdk"

Rust library

You will need a custom Rust nightly toolchain. The canonicalize.patch file should be applied to the beta branch of the official Rust repository. Build the toolchain by following the steps below:

# clone repos
git clone https://github.com/antmicro/wasi_ext_lib.git
git clone https://github.com/rust-lang/rust.git

# apply patch to official Rust repo
cd rust
git checkout beta
git apply ../wasi_ext_lib/canonicalize.patch

# build toolchain, remember to meet all dependencies required by Rust
./configure --target=wasm32-wasi --disable-docs --set target.wasm32-wasi.wasi-root=${WASI_SDK_PATH}/share/wasi-sysroot --enable-lld --tools=cargo
./x.py build --target wasm32-wasi --target x86_64-unknown-linux-gnu --stage 1

# link toolchain and build `wasi_ext_lib`
rustup toolchain link wasi_extended "$(pwd)/build/host/stage1"

Note that rustup toolchain link command only creates a symlink to the given target. If you choose to remove rust sources after building the toolchain, make sure that stage1 directory is still under the linked path (the directory can be moved somewhere else and linked from there).

After the toolchain is installed, the library can be compiled using:

cargo +wasi_extended build --target wasm32-wasi --release

C library

In order to build the C library, run:

(cd c_lib && make)

This command produces libwasi_ext_lib.a file in c_lib/bin directory. It is a static library, you can link it by appending -L<path_to_wasi_ext_lib>/c_lib/bin -lwasi_ext_lib to the clang command.