Files
wasmtime/crates/wasi-common
Alex Crichton 3dd5a3cb3f Reimplement wasmtime-wasi on top of wasmtime (#899)
* Reimplement `wasmtime-wasi` on top of `wasmtime`

This commit reimplements the `wasmtime-wasi` crate on top of the
`wasmtime` API crate, instead of being placed on top of the `wasmtime-*`
family of internal crates. The purpose here is to continue to exercise
the API as well as avoid usage of internals wherever possible and
instead use the safe API as much as possible.

The `wasmtime-wasi` crate's API has been updated as part of this PR as
well. The general outline of it is now:

* Each module snapshot has a `WasiCtxBuilder`, `WasiCtx`, and `Wasi`
  type.
  * The `WasiCtx*` types are reexported from `wasi-common`.
  * The `Wasi` type is synthesized by the `wig` crate's procedural macro
* The `Wasi` type exposes one constructor which takes a `Store` and a
  `WasiCtx`, and produces a `Wasi`
* Each `Wasi` struct fields for all the exported functions in that wasi
  module. They're all public an they all have type `wasmtime::Func`
* The `Wasi` type has a `get_export` method to fetch an struct field by
  name.

The intention here is that we can continue to make progress on #727 by
integrating WASI construction into the `Instance::new` experience, but
it requires everything to be part of the same system!

The main oddity required by the `wasmtime-wasi` crate is that it needs
access to the caller's `memory` export, if any. This is currently done
with a bit of a hack and is expected to go away once interface types are
more fully baked in.

* Remove now no-longer-necessary APIs from `wasmtime`

* rustfmt

* Rename to from_abi
2020-02-06 09:23:06 -06:00
..
2020-01-24 12:30:38 -08:00
2020-01-09 21:57:40 -08:00
2020-01-09 21:57:40 -08:00
2019-11-08 06:35:40 -08:00
2019-11-08 06:35:40 -08:00

wasi-common

A Bytecode Alliance project

A library providing a common implementation of WASI hostcalls for re-use in any WASI-enabled runtime.

Crates.io version Download docs.rs docs

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_recv
  • sock_send
  • sock_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.