# Executing WebAssembly in Teaclave
Teaclave integrates WebAssembly Micro Runtime as an executor, which can interpret WebAssembly bytecode in a sandboxed environment. Theoretically, source code written in any language which can be compiled to WebAssembly should also be executable in Teaclave. However, in order to be more secure, Teaclave cannot provide interfaces such as syscalls to legacy applications, so the source code should:
- Be self-contained: not depending on libraries which are not provided by Teaclave, including standard libraries.
- Contains no syscall: no system call-related code.
- Implement required interface: exporting an
int entrypoint(int argc, char* argv)function which is compatible with Teaclave WAMR calling convention (see examples for more details).
Currently, Teaclave file system APIs are supported. We also provide examples for compiling and executing from source code of various languages.
In current Teaclave client SDK, when passing arguments to the registered
(key, value) pair is converted into two string pointers in
argv and you should expect
argc is as twice as the actual number of
arguments. The calling convention is subject to further changes.
# From C
wasm32 can be used for compiling Teaclave-compatible WASM
bytecode. Remember to add following options while compiling:
--target=wasm32 \ -nostdlib \ -Wl,--no-entry \ -Wl,--export-all, \ -Wl,--allow-undefined
Alternatively, C and C++ code can be compiled with zig:
zig cc -Os --target=wasm32-freestanding -shared -o example.wasm example.c zig c++ -Os --target=wasm32-freestanding -shared -o example.wasm example.cpp
# From Rust
First of all, your cargo should support
wasm32 target and
required to reduce the size of generated binary. You can easily run the
following commands to install dependencies:
rustup target add wasm32-unknown-unknown cargo install wasm-gc
There should be an exported
entrypoint function in the source code, so you can
cargo to create a new library and generate it with
cargo build --target wasm32-unknown-unknown. Please also add
crate-type = ["cdylib"] in
[lib] section into your
Cargo.toml file to let cargo generate WASM file.
To reduce the size of WASM file, run:
cargo build --target wasm32-unknown-unknown --release wasm-gc target/wasm32-unknown-unknown/release/[WASM FILENAME]
For detailed optimization options and function signature, please refer to the example payload.