060f12571d
* wiggle: adapt Wiggle strings for shared use This is an extension of #5229 for the `&str` and `&mut str` types. As documented there, we are attempting to maintain Rust guarantees for slices that Wiggle hands out in the presence of WebAssembly shared memory, in which case multiple threads could be modifying the underlying data of the slice. This change changes the API of `GuestPtr` to return an `Option` which is `None` when attempting to view the WebAssembly data as a string and the underlying WebAssembly memory is shared. This reuses the `UnsafeGuestSlice` structure from #5229 to do so and appropriately marks the region as borrowed in Wiggle's manual borrow checker. Each original call site in this project's WASI implementations is fixed up to `expect` that a non-shared memory is used. (Note that I can find no uses of `GuestStrMut` in the WASI implementations). * wiggle: make `GuestStr*` containers wrappers of `GuestSlice*` This change makes it possible to reuse the underlying logic in `UnsafeGuestSlice` and the `GuestSlice*` implementations to continue to expose the `GuestStr` and `GuestStrMut` types. These types now are simple wrappers of their `GuestSlice*` variant. The UTF-8 validation that distinguished `GuestStr*` now lives in the `TryFrom` implementations for each type.
wasmtime-wasi-crypto
This crate enables support for the wasi-crypto APIs in Wasmtime.
The sole purpose of the implementation is to allow bindings and application developers to test the proposed APIs. This implementation is not meant to be used in production. Like the specification, it is currently experimental and its functionality can quickly change.
Since the wasi-crypto API is expected to be an optional feature of WASI, this crate is currently separate from the wasi-common crate.
Wasmtime integration
Use the Wasmtime APIs to instantiate a Wasm module and link the
wasi-crypto modules as follows:
use wasmtime_wasi_crypto::{
WasiCryptoAsymmetricCommon, WasiCryptoCommon, WasiCryptoCtx, WasiCryptoSignatures,
WasiCryptoSymmetric,
};
let cx_crypto = WasiCryptoCtx::new();
WasiCryptoCommon::new(linker.store(), cx_crypto.clone()).add_to_linker(linker)?;
WasiCryptoAsymmetricCommon::new(linker.store(), cx_crypto.clone()).add_to_linker(linker)?;
WasiCryptoSignatures::new(linker.store(), cx_crypto.clone()).add_to_linker(linker)?;
WasiCryptoSymmetric::new(linker.store(), cx_crypto.clone()).add_to_linker(linker)?;
let wasi = wasmtime_wasi::old::snapshot_0::Wasi::new(linker.store(), mk_cx()?);
wasi.add_to_linker(linker)?;
Building Wasmtime
Wasmtime must be compiled with the wasi-crypto feature flag
(disabled by default) in order to include the crypto APIs.
Examples
Example rust bindings and assemblyscript bindings are provided to demonstrate how these APIs can be used and exposed to applications in an idiomatic way.