Update preview1 to trap on misaligned pointers #6776
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Previously Wasmtime would return `EINVAL` to a guest but the upstream documentation indicates that misaligned pointers should trap, so this commit updates the alignment error to get converted into a trap rather than than being returned to the guest.
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@pchickey I'd also be interested in your thoughts on the behvaior of out-of-bounds pointers as well. The linked documentation doesn't specifically say what to do in that case so I left it as-is with EFAULT for now, but should the docs perhaps be updated to indicate that a trap should happen in that situation as well? |
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There's actually been an outstanding PR to update that language to trap, as well: WebAssembly/WASI#536. I agreed then we should merge it, but it fell off my radar. cc @yamt |
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I merged the pointer out of bounds changes upstream, so you can also change the PtrOutOfBounds and PtrOverflow cases to trap.
The new preview 1 implementation inside wasi/src/preview2/preview1 should also be updated as well. Unfortunately, it looks like instead of using a From impl there, it instead uses a pattern of Result<_, GuestError>::or(Err(Errno::Inval)) at each call site, so that is a tougher job. Its OK to not take that on as part of this PR, but we should file an issue on it if you want to defer it.
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Sounds good! I think I covered all the bases here, but would be good to double-check |
… feature/preview2 * 'feature/preview2' of github.com:geekbeast/wasmtime: Change preview2 builder methods to use `&mut self` (bytecodealliance#6770) Add a bindgen test that exercises using error types from a different interface (bytecodealliance#6802) Resolve trappable error types with fully qualified package paths (bytecodealliance#6795) Update the dev-dependency for wit-bindgen to 0.9.0 (bytecodealliance#6800) Fix incorrect sample code in documentation (bytecodealliance#6796) (bytecodealliance#6797) Update preview1 to trap on misaligned pointers (bytecodealliance#6776) Fix posix-signals-on-macos on aarch64-apple-darwin (bytecodealliance#6793) consistient WASI preview1 rights reporting (bytecodealliance#6784) Wasmtime: Introduce `{Module,Component}::resources_required` (bytecodealliance#6789)
* Update preview1 to trap on misaligned pointers Previously Wasmtime would return `EINVAL` to a guest but the upstream documentation indicates that misaligned pointers should trap, so this commit updates the alignment error to get converted into a trap rather than than being returned to the guest. * Change OOB errors to traps too * Update preview2's implementation of preview1 * Handle some more errors
Previously Wasmtime would return
EINVALto a guest but the upstream documentation indicates that misaligned pointers should trap, so this commit updates the alignment error to get converted into a trap rather than than being returned to the guest.