3dd5a3cb3f
* 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
84 lines
2.7 KiB
Rust
84 lines
2.7 KiB
Rust
use anyhow::{bail, Context};
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use std::fs::File;
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use std::path::Path;
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use wasmtime::{Instance, Module, Store};
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pub fn instantiate(data: &[u8], bin_name: &str, workspace: Option<&Path>) -> anyhow::Result<()> {
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let store = Store::default();
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let get_preopens = |workspace: Option<&Path>| -> anyhow::Result<Vec<_>> {
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if let Some(workspace) = workspace {
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let preopen_dir = wasi_common::preopen_dir(workspace)
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.context(format!("error while preopening {:?}", workspace))?;
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Ok(vec![(".".to_owned(), preopen_dir)])
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} else {
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Ok(vec![])
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}
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};
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// Create our wasi context with pretty standard arguments/inheritance/etc.
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// Additionally register andy preopened directories if we have them.
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let mut builder = wasi_common::WasiCtxBuilder::new()
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.arg(bin_name)
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.arg(".")
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.inherit_stdio();
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for (dir, file) in get_preopens(workspace)? {
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builder = builder.preopened_dir(file, dir);
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}
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// The nonstandard thing we do with `WasiCtxBuilder` is to ensure that
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// `stdin` is always an unreadable pipe. This is expected in the test suite
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// where `stdin` is never ready to be read. In some CI systems, however,
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// stdin is closed which causes tests to fail.
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let (reader, _writer) = os_pipe::pipe()?;
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builder = builder.stdin(reader_to_file(reader));
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let snapshot1 = wasmtime_wasi::Wasi::new(&store, builder.build()?);
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let module = Module::new(&store, &data).context("failed to create wasm module")?;
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let imports = module
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.imports()
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.iter()
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.map(|i| {
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let field_name = i.name();
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if let Some(export) = snapshot1.get_export(field_name) {
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Ok(export.clone().into())
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} else {
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bail!(
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"import {} was not found in module {}",
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field_name,
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i.module(),
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)
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}
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})
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.collect::<Result<Vec<_>, _>>()?;
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let instance = Instance::new(&module, &imports).context(format!(
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"error while instantiating Wasm module '{}'",
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bin_name,
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))?;
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let export = instance
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.get_export("_start")
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.context("expected a _start export")?
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.clone();
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export
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.func()
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.context("expected export to be a func")?
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.call(&[])?;
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Ok(())
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}
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#[cfg(unix)]
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fn reader_to_file(reader: os_pipe::PipeReader) -> File {
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use std::os::unix::prelude::*;
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unsafe { File::from_raw_fd(reader.into_raw_fd()) }
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}
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#[cfg(windows)]
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fn reader_to_file(reader: os_pipe::PipeReader) -> File {
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use std::os::windows::prelude::*;
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unsafe { File::from_raw_handle(reader.into_raw_handle()) }
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}
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