wasmtime_wasi/
lib.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
//! # Wasmtime's WASI Implementation
//!
//! This crate provides a Wasmtime host implementation of WASI 0.2 (aka WASIp2
//! aka Preview 2) and WASI 0.1 (aka WASIp1 aka Preview 1). WASI is implemented
//! with the Rust crates [`tokio`] and [`cap-std`] primarily, meaning that
//! operations are implemented in terms of their native platform equivalents by
//! default.
//!
//! For components and WASIp2, continue reading below. For WASIp1 and core
//! modules, see the [`preview1`] module documentation.
//!
//! # WASIp2 interfaces
//!
//! This crate contains implementations of the following interfaces:
//!
//! * [`wasi:cli/environment`]
//! * [`wasi:cli/exit`]
//! * [`wasi:cli/stderr`]
//! * [`wasi:cli/stdin`]
//! * [`wasi:cli/stdout`]
//! * [`wasi:cli/terminal-input`]
//! * [`wasi:cli/terminal-output`]
//! * [`wasi:cli/terminal-stderr`]
//! * [`wasi:cli/terminal-stdin`]
//! * [`wasi:cli/terminal-stdout`]
//! * [`wasi:clocks/monotonic-clock`]
//! * [`wasi:clocks/wall-clock`]
//! * [`wasi:filesystem/preopens`]
//! * [`wasi:filesystem/types`]
//! * [`wasi:io/error`]
//! * [`wasi:io/poll`]
//! * [`wasi:io/streams`]
//! * [`wasi:random/insecure-seed`]
//! * [`wasi:random/insecure`]
//! * [`wasi:random/random`]
//! * [`wasi:sockets/instance-network`]
//! * [`wasi:sockets/ip-name-lookup`]
//! * [`wasi:sockets/network`]
//! * [`wasi:sockets/tcp-create-socket`]
//! * [`wasi:sockets/tcp`]
//! * [`wasi:sockets/udp-create-socket`]
//! * [`wasi:sockets/udp`]
//!
//! All traits are implemented in terms of a [`WasiView`] trait which provides
//! basic access to [`WasiCtx`], configuration for WASI, and [`ResourceTable`],
//! the state for all host-defined component model resources.
//!
//! # Generated Bindings
//!
//! This crate uses [`wasmtime::component::bindgen!`] to generate bindings for
//! all WASI interfaces. Raw bindings are available in the [`bindings`] module
//! of this crate. Downstream users can either implement these traits themselves
//! or you can use the built-in implementations in this crate for
//! `WasiImpl<T: WasiView>`.
//!
//! # The `WasiView` trait
//!
//! This crate's implementation of WASI is done in terms of an implementation of
//! [`WasiView`]. This trait provides a "view" into WASI-related state that is
//! contained within a [`Store<T>`](wasmtime::Store). All implementations of
//! traits look like:
//!
//! ```
//! # use wasmtime_wasi::WasiImpl;
//! # trait WasiView {}
//! # mod bindings { pub mod wasi { pub trait Host {} } }
//! impl<T: WasiView> bindings::wasi::Host for WasiImpl<T> {
//!     // ...
//! }
//! ```
//!
//! The [`add_to_linker_sync`] and [`add_to_linker_async`] function then require
//! that `T: WasiView` with [`Linker<T>`](wasmtime::component::Linker).
//!
//! To implement the [`WasiView`] trait you will first select a `T` to put in
//! `Store<T>`. Next you'll implement the [`WasiView`] trait for `T`. Somewhere
//! within `T` you'll store:
//!
//! * [`WasiCtx`] - created through [`WasiCtxBuilder`].
//! * [`ResourceTable`] - created through default constructors.
//!
//! These two fields are then accessed through the methods of [`WasiView`].
//!
//! # Async and Sync
//!
//! Many WASI functions are not blocking from WebAssembly's point of view, but
//! for those that do they're provided in two flavors: asynchronous and
//! synchronous. Which version you will use depends on how
//! [`Config::async_support`][async] is set.
//!
//! * For non-async users (the default of `Config`), use [`add_to_linker_sync`].
//! * For async users, use [`add_to_linker_async`].
//!
//! Note that bindings are generated once for async and once for sync. Most
//! interfaces do not change, however, so only interfaces with blocking
//! functions have bindings generated twice. Bindings are organized as:
//!
//! * [`bindings`] - default location of all bindings, blocking functions are
//!   `async`
//! * [`bindings::sync`] - blocking interfaces have synchronous versions here.
//!
//! # Crate-specific traits
//!
//! This crate's default implementation of WASI bindings to native primitives
//! for the platform that it is compiled for. For example opening a TCP socket
//! uses the native platform to open a TCP socket (so long as [`WasiCtxBuilder`]
//! allows it). There are a few important traits, however, that are specific to
//! this crate.
//!
//! * [`HostInputStream`] and [`HostOutputStream`] - these are the host traits
//!   behind the WASI `input-stream` and `output-stream` types in the
//!   `wasi:io/streams` interface. These enable embedders to build their own
//!   custom stream and insert them into a [`ResourceTable`] to be used from
//!   wasm.
//!
//! * [`Subscribe`] - this trait enables building arbitrary logic to get hooked
//!   into a `pollable` resource from `wasi:io/poll`. A pollable resource is
//!   created through the [`subscribe`] function.
//!
//! * [`HostWallClock`] and [`HostMonotonicClock`] are used in conjunction with
//!   [`WasiCtxBuilder::wall_clock`] and [`WasiCtxBuilder::monotonic_clock`] if
//!   the defaults host's clock should not be used.
//!
//! * [`StdinStream`] and [`StdoutStream`] are used to provide custom
//!   stdin/stdout streams if they're not inherited (or null, which is the
//!   default).
//!
//! These traits enable embedders to customize small portions of WASI interfaces
//! provided while still providing all other interfaces.
//!
//! # Examples
//!
//! Usage of this crate is done through a few steps to get everything hooked up:
//!
//! 1. First implement [`WasiView`] for your type which is the `T` in
//!    `Store<T>`.
//! 2. Add WASI interfaces to a `wasmtime::component::Linker<T>`. This is either
//!    done through top-level functions like [`add_to_linker_sync`] or through
//!    individual `add_to_linker` functions in generated bindings throughout
//!    this crate.
//! 3. Create a [`WasiCtx`] for each `Store<T>` through [`WasiCtxBuilder`]. Each
//!    WASI context is "null" or "empty" by default, so items must be explicitly
//!    added to get accessed by wasm (such as env vars or program arguments).
//! 4. Use the previous `Linker<T>` to instantiate a `Component` within a
//!    `Store<T>`.
//!
//! For examples see each of [`WasiView`], [`WasiCtx`], [`WasiCtxBuilder`],
//! [`add_to_linker_sync`], and [`bindings::Command`].
//!
//! [`wasmtime::component::bindgen!`]: https://docs.rs/wasmtime/latest/wasmtime/component/macro.bindgen.html
//! [`tokio`]: https://crates.io/crates/tokio
//! [`cap-std`]: https://crates.io/crates/cap-std
//! [`wasi:cli/environment`]: bindings::cli::environment::Host
//! [`wasi:cli/exit`]: bindings::cli::exit::Host
//! [`wasi:cli/stderr`]: bindings::cli::stderr::Host
//! [`wasi:cli/stdin`]: bindings::cli::stdin::Host
//! [`wasi:cli/stdout`]: bindings::cli::stdout::Host
//! [`wasi:cli/terminal-input`]: bindings::cli::terminal_input::Host
//! [`wasi:cli/terminal-output`]: bindings::cli::terminal_output::Host
//! [`wasi:cli/terminal-stdin`]: bindings::cli::terminal_stdin::Host
//! [`wasi:cli/terminal-stdout`]: bindings::cli::terminal_stdout::Host
//! [`wasi:cli/terminal-stderr`]: bindings::cli::terminal_stderr::Host
//! [`wasi:clocks/monotonic-clock`]: bindings::clocks::monotonic_clock::Host
//! [`wasi:clocks/wall-clock`]: bindings::clocks::wall_clock::Host
//! [`wasi:filesystem/preopens`]: bindings::filesystem::preopens::Host
//! [`wasi:filesystem/types`]: bindings::filesystem::types::Host
//! [`wasi:io/error`]: bindings::io::error::Host
//! [`wasi:io/poll`]: bindings::io::poll::Host
//! [`wasi:io/streams`]: bindings::io::streams::Host
//! [`wasi:random/insecure-seed`]: bindings::random::insecure_seed::Host
//! [`wasi:random/insecure`]: bindings::random::insecure::Host
//! [`wasi:random/random`]: bindings::random::random::Host
//! [`wasi:sockets/instance-network`]: bindings::sockets::instance_network::Host
//! [`wasi:sockets/ip-name-lookup`]: bindings::sockets::ip_name_lookup::Host
//! [`wasi:sockets/network`]: bindings::sockets::network::Host
//! [`wasi:sockets/tcp-create-socket`]: bindings::sockets::tcp_create_socket::Host
//! [`wasi:sockets/tcp`]: bindings::sockets::tcp::Host
//! [`wasi:sockets/udp-create-socket`]: bindings::sockets::udp_create_socket::Host
//! [`wasi:sockets/udp`]: bindings::sockets::udp::Host
//! [async]: https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.async_support
//! [`ResourceTable`]: wasmtime::component::ResourceTable

#![cfg_attr(docsrs, feature(doc_auto_cfg))]
#![expect(clippy::allow_attributes_without_reason, reason = "crate not migrated")]

use wasmtime::component::Linker;

pub mod bindings;
mod clocks;
mod ctx;
mod error;
mod filesystem;
mod host;
mod ip_name_lookup;
mod network;
pub mod pipe;
mod poll;
#[cfg(feature = "preview1")]
pub mod preview0;
#[cfg(feature = "preview1")]
pub mod preview1;
mod random;
pub mod runtime;
mod stdio;
mod stream;
mod tcp;
mod udp;
mod write_stream;

pub use self::clocks::{HostMonotonicClock, HostWallClock};
pub use self::ctx::{WasiCtx, WasiCtxBuilder, WasiImpl, WasiView};
pub use self::error::{I32Exit, TrappableError};
pub use self::filesystem::{DirPerms, FileInputStream, FilePerms, FsError, FsResult};
pub use self::network::{Network, SocketAddrUse, SocketError, SocketResult};
pub use self::poll::{subscribe, ClosureFuture, MakeFuture, Pollable, PollableFuture, Subscribe};
pub use self::random::{thread_rng, Deterministic};
pub use self::stdio::{
    stderr, stdin, stdout, AsyncStdinStream, AsyncStdoutStream, IsATTY, OutputFile, Stderr, Stdin,
    StdinStream, Stdout, StdoutStream,
};
pub use self::stream::{
    HostInputStream, HostOutputStream, InputStream, OutputStream, StreamError, StreamResult,
};
#[doc(no_inline)]
pub use async_trait::async_trait;
#[doc(no_inline)]
pub use cap_fs_ext::SystemTimeSpec;
#[doc(no_inline)]
pub use cap_rand::RngCore;
#[doc(no_inline)]
pub use wasmtime::component::{ResourceTable, ResourceTableError};

/// Add all WASI interfaces from this crate into the `linker` provided.
///
/// This function will add the `async` variant of all interfaces into the
/// [`Linker`] provided. By `async` this means that this function is only
/// compatible with [`Config::async_support(true)`][async]. For embeddings with
/// async support disabled see [`add_to_linker_sync`] instead.
///
/// This function will add all interfaces implemented by this crate to the
/// [`Linker`], which corresponds to the `wasi:cli/imports` world supported by
/// this crate.
///
/// [async]: wasmtime::Config::async_support
///
/// # Example
///
/// ```
/// use wasmtime::{Engine, Result, Store, Config};
/// use wasmtime::component::{ResourceTable, Linker};
/// use wasmtime_wasi::{WasiCtx, WasiView, WasiCtxBuilder};
///
/// fn main() -> Result<()> {
///     let mut config = Config::new();
///     config.async_support(true);
///     let engine = Engine::new(&config)?;
///
///     let mut linker = Linker::<MyState>::new(&engine);
///     wasmtime_wasi::add_to_linker_async(&mut linker)?;
///     // ... add any further functionality to `linker` if desired ...
///
///     let mut builder = WasiCtxBuilder::new();
///
///     // ... configure `builder` more to add env vars, args, etc ...
///
///     let mut store = Store::new(
///         &engine,
///         MyState {
///             ctx: builder.build(),
///             table: ResourceTable::new(),
///         },
///     );
///
///     // ... use `linker` to instantiate within `store` ...
///
///     Ok(())
/// }
///
/// struct MyState {
///     ctx: WasiCtx,
///     table: ResourceTable,
/// }
///
/// impl WasiView for MyState {
///     fn ctx(&mut self) -> &mut WasiCtx { &mut self.ctx }
///     fn table(&mut self) -> &mut ResourceTable { &mut self.table }
/// }
/// ```
pub fn add_to_linker_async<T: WasiView>(linker: &mut Linker<T>) -> anyhow::Result<()> {
    let options = crate::bindings::LinkOptions::default();
    add_to_linker_with_options_async(linker, &options)
}

/// Similar to [`add_to_linker_async`], but with the ability to enable unstable features.
pub fn add_to_linker_with_options_async<T: WasiView>(
    linker: &mut Linker<T>,
    options: &crate::bindings::LinkOptions,
) -> anyhow::Result<()> {
    let l = linker;
    let closure = type_annotate::<T, _>(|t| WasiImpl(t));

    crate::bindings::clocks::wall_clock::add_to_linker_get_host(l, closure)?;
    crate::bindings::clocks::monotonic_clock::add_to_linker_get_host(l, closure)?;
    crate::bindings::filesystem::types::add_to_linker_get_host(l, closure)?;
    crate::bindings::filesystem::preopens::add_to_linker_get_host(l, closure)?;
    crate::bindings::io::error::add_to_linker_get_host(l, closure)?;
    crate::bindings::io::poll::add_to_linker_get_host(l, closure)?;
    crate::bindings::io::streams::add_to_linker_get_host(l, closure)?;
    crate::bindings::random::random::add_to_linker_get_host(l, closure)?;
    crate::bindings::random::insecure::add_to_linker_get_host(l, closure)?;
    crate::bindings::random::insecure_seed::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::exit::add_to_linker_get_host(l, &options.into(), closure)?;
    crate::bindings::cli::environment::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::stdin::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::stdout::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::stderr::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::terminal_input::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::terminal_output::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::terminal_stdin::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::terminal_stdout::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::terminal_stderr::add_to_linker_get_host(l, closure)?;
    crate::bindings::sockets::tcp::add_to_linker_get_host(l, closure)?;
    crate::bindings::sockets::tcp_create_socket::add_to_linker_get_host(l, closure)?;
    crate::bindings::sockets::udp::add_to_linker_get_host(l, closure)?;
    crate::bindings::sockets::udp_create_socket::add_to_linker_get_host(l, closure)?;
    crate::bindings::sockets::instance_network::add_to_linker_get_host(l, closure)?;
    crate::bindings::sockets::network::add_to_linker_get_host(l, &options.into(), closure)?;
    crate::bindings::sockets::ip_name_lookup::add_to_linker_get_host(l, closure)?;
    Ok(())
}

/// Add all WASI interfaces from this crate into the `linker` provided.
///
/// This function will add the synchronous variant of all interfaces into the
/// [`Linker`] provided. By synchronous this means that this function is only
/// compatible with [`Config::async_support(false)`][async]. For embeddings
/// with async support enabled see [`add_to_linker_async`] instead.
///
/// This function will add all interfaces implemented by this crate to the
/// [`Linker`], which corresponds to the `wasi:cli/imports` world supported by
/// this crate.
///
/// [async]: wasmtime::Config::async_support
///
/// # Example
///
/// ```
/// use wasmtime::{Engine, Result, Store, Config};
/// use wasmtime::component::{ResourceTable, Linker};
/// use wasmtime_wasi::{WasiCtx, WasiView, WasiCtxBuilder};
///
/// fn main() -> Result<()> {
///     let engine = Engine::default();
///
///     let mut linker = Linker::<MyState>::new(&engine);
///     wasmtime_wasi::add_to_linker_sync(&mut linker)?;
///     // ... add any further functionality to `linker` if desired ...
///
///     let mut builder = WasiCtxBuilder::new();
///
///     // ... configure `builder` more to add env vars, args, etc ...
///
///     let mut store = Store::new(
///         &engine,
///         MyState {
///             ctx: builder.build(),
///             table: ResourceTable::new(),
///         },
///     );
///
///     // ... use `linker` to instantiate within `store` ...
///
///     Ok(())
/// }
///
/// struct MyState {
///     ctx: WasiCtx,
///     table: ResourceTable,
/// }
///
/// impl WasiView for MyState {
///     fn ctx(&mut self) -> &mut WasiCtx { &mut self.ctx }
///     fn table(&mut self) -> &mut ResourceTable { &mut self.table }
/// }
/// ```
pub fn add_to_linker_sync<T: WasiView>(
    linker: &mut wasmtime::component::Linker<T>,
) -> anyhow::Result<()> {
    let options = crate::bindings::sync::LinkOptions::default();
    add_to_linker_with_options_sync(linker, &options)
}

/// Similar to [`add_to_linker_sync`], but with the ability to enable unstable features.
pub fn add_to_linker_with_options_sync<T: WasiView>(
    linker: &mut wasmtime::component::Linker<T>,
    options: &crate::bindings::sync::LinkOptions,
) -> anyhow::Result<()> {
    let l = linker;
    let closure = type_annotate::<T, _>(|t| WasiImpl(t));

    crate::bindings::clocks::wall_clock::add_to_linker_get_host(l, closure)?;
    crate::bindings::clocks::monotonic_clock::add_to_linker_get_host(l, closure)?;
    crate::bindings::sync::filesystem::types::add_to_linker_get_host(l, closure)?;
    crate::bindings::filesystem::preopens::add_to_linker_get_host(l, closure)?;
    crate::bindings::io::error::add_to_linker_get_host(l, closure)?;
    crate::bindings::sync::io::poll::add_to_linker_get_host(l, closure)?;
    crate::bindings::sync::io::streams::add_to_linker_get_host(l, closure)?;
    crate::bindings::random::random::add_to_linker_get_host(l, closure)?;
    crate::bindings::random::insecure::add_to_linker_get_host(l, closure)?;
    crate::bindings::random::insecure_seed::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::exit::add_to_linker_get_host(l, &options.into(), closure)?;
    crate::bindings::cli::environment::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::stdin::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::stdout::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::stderr::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::terminal_input::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::terminal_output::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::terminal_stdin::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::terminal_stdout::add_to_linker_get_host(l, closure)?;
    crate::bindings::cli::terminal_stderr::add_to_linker_get_host(l, closure)?;
    crate::bindings::sync::sockets::tcp::add_to_linker_get_host(l, closure)?;
    crate::bindings::sockets::tcp_create_socket::add_to_linker_get_host(l, closure)?;
    crate::bindings::sync::sockets::udp::add_to_linker_get_host(l, closure)?;
    crate::bindings::sockets::udp_create_socket::add_to_linker_get_host(l, closure)?;
    crate::bindings::sockets::instance_network::add_to_linker_get_host(l, closure)?;
    crate::bindings::sockets::network::add_to_linker_get_host(l, &options.into(), closure)?;
    crate::bindings::sockets::ip_name_lookup::add_to_linker_get_host(l, closure)?;
    Ok(())
}

// NB: workaround some rustc inference - a future refactoring may make this
// obsolete.
fn type_annotate<T: WasiView, F>(val: F) -> F
where
    F: Fn(&mut T) -> WasiImpl<&mut T>,
{
    val
}