773915b4bf
* Introduce WasiCtxBuilderError error type `WasiCtxBuilderError` is the `wasi-common` client-facing error type which is exclusively thrown when building a new `WasiCtx` instance. As such, building such an instance should not require the client to understand different WASI errno values as was assumed until now. This commit is a first step at streamlining error handling in `wasi-common` and makes way for the `wiggle` crate. When adding the `WasiCtxBuilderError`, I've had to do two things of notable importance: 1. I've removed a couple of `ok_or` calls in `WasiCtxBuilder::build` and replaced them with `unwrap`s, following the same pattern in different builder methods above. This is fine since we _always_ operate on non-empty `Option`s in `WasiCtxBuilder` thus `unwrap`ing will never fail. On the other hand, this might be a good opportunity to rethink the structure of our builder, and how we good remove the said `Option`s especially since we always populate them with empty containers to begin with. I understand this is to make chaining of builder methods easier which take and return `&mut self` and the same applies to `WasiCtxBuilder::build(&mut self)` method, but perhaps it would more cleanly signal the intentions if we simply moved `WasiCtxBuilder` instance around. Food for thought! 2. Methods specific to determining rights of passed around `std::fs::File` objects when populating `WasiCtx` `FdEntry` entities now return `io::Error` directly so that we can reuse them in `WasiCtxBuilder` methods (returning `WasiCtxBuilderError` error type), and in syscalls (returning WASI errno). * Return WasiError directly in syscalls Also, removes `error::Error` type altogether. Now, `io::Error` and related are automatically converted to their corresponding WASI errno value encapsulated as `WasiError`. While here, it made sense to me to move `WasiError` to `wasi` module which will align itself well with the upcoming changes introduced by `wiggle`. To different standard `Result` from WASI specific, I've created a helper alias `WasiResult` also residing in `wasi` module. * Update wig * Add from ffi::NulError and pass context to NotADirectory * Add dummy commit to test CI
wasi-common
A Bytecode Alliance project
A library providing a common implementation of WASI hostcalls for re-use in any WASI-enabled runtime.
The wasi-common crate will ultimately serve as a library providing a common implementation of
WASI hostcalls for re-use in any WASI (and potentially non-WASI) runtimes
such as Wasmtime and Lucet.
The library is an adaption of lucet-wasi crate from the Lucet project, and it is currently based on 40ae1df git revision.
Please note that the library requires Rust compiler version at least 1.37.0.
Supported syscalls
*nix
In our *nix implementation, we currently support the entire WASI API with the exception of socket hostcalls:
sock_recvsock_sendsock_shutdown
We expect these to be implemented when network access is standardised.
We also currently do not support the proc_raise hostcall, as it is expected to
be dropped entirely from WASI.
Windows
In our Windows implementation, we currently support the minimal subset of WASI API which allows for running the very basic "Hello world!" style WASM apps. More coming shortly, so stay tuned!
Development hints
When testing the crate, you may want to enable and run full wasm32 integration testsuite. This
requires wasm32-wasi target installed which can be done as follows using rustup
rustup target add wasm32-wasi
Now, you should be able to run the integration testsuite by running cargo test on the
test-programs package with test_programs feature enabled:
cargo test --features test_programs --package test-programs
Third-Party Code
Significant parts of our hostcall implementations are derived from the C implementations in
cloudabi-utils. See LICENSE.cloudabi-utils for license information.