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
#![deny(missing_docs)]
use std::fmt;
use std::future::Future;
use std::pin::Pin;
use std::task::{Context, Poll};
use tokio::io::{AsyncRead, AsyncWrite};
use tokio::{io, task};
use wasmer::RuntimeError;
use wasmer_wasi::WasiStateBuilder;
mod pipe;
mod stdio;
pub use stdio::{Stderr, Stdin, Stdout};
use pipe::LockPipe;
pub fn add_stdio(state: &mut WasiStateBuilder) -> &mut WasiStateBuilder {
state
.stdin(Box::new(stdio::Stdin))
.stdout(Box::new(stdio::Stdout))
.stderr(Box::new(stdio::Stderr))
}
tokio::task_local! {
static STDIN: LockPipe;
static STDOUT: LockPipe;
static STDERR: LockPipe;
}
pub struct WasiStdin {
inner: LockPipe,
}
impl AsyncWrite for WasiStdin {
#[inline]
fn poll_write(self: Pin<&mut Self>, cx: &mut Context, buf: &[u8]) -> Poll<io::Result<usize>> {
Pin::new(&mut &self.inner).poll_write(cx, buf)
}
#[inline]
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context) -> Poll<io::Result<()>> {
Pin::new(&mut &self.inner).poll_flush(cx)
}
#[inline]
fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context) -> Poll<io::Result<()>> {
Pin::new(&mut &self.inner).poll_shutdown(cx)
}
}
pub struct WasiStdout {
inner: LockPipe,
}
impl AsyncRead for WasiStdout {
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut io::ReadBuf,
) -> Poll<io::Result<()>> {
Pin::new(&mut &self.inner).poll_read(cx, buf)
}
}
pub struct WasiStderr {
inner: LockPipe,
}
impl AsyncRead for WasiStderr {
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut io::ReadBuf,
) -> Poll<io::Result<()>> {
Pin::new(&mut &self.inner).poll_read(cx, buf)
}
}
#[must_use = "WasiProcess does nothing without being polled or spawned. Try calling `.spawn()`"]
pub struct WasiProcess {
pub stdin: Option<WasiStdin>,
pub stdout: Option<WasiStdout>,
pub stderr: Option<WasiStderr>,
handle: Pin<Box<dyn Future<Output = Result<(), RuntimeError>> + Send + Sync>>,
}
#[derive(Debug, Copy, Clone)]
pub struct MaxBufSize {
pub stdin: usize,
pub stdout: usize,
pub stderr: usize,
}
const DEFAULT_BUF_SIZE: usize = 1024;
impl Default for MaxBufSize {
fn default() -> Self {
MaxBufSize {
stdin: DEFAULT_BUF_SIZE,
stdout: DEFAULT_BUF_SIZE,
stderr: DEFAULT_BUF_SIZE,
}
}
}
impl WasiProcess {
pub fn new(
instance: &wasmer::Instance,
buf_size: MaxBufSize,
) -> Result<Self, wasmer::ExportError> {
let start = instance.exports.get_function("_start")?.clone();
Ok(Self::with_function(start, buf_size))
}
pub fn with_function(start_function: wasmer::Function, buf_size: MaxBufSize) -> Self {
let stdin = LockPipe::new(buf_size.stdin);
let stdout = LockPipe::new(buf_size.stdout);
let stderr = LockPipe::new(buf_size.stderr);
let handle = STDIN.scope(
stdin.clone(),
STDOUT.scope(
stdout.clone(),
STDERR.scope(stderr.clone(), async move {
task::block_in_place(|| start_function.call(&[]).map(drop))
}),
),
);
Self {
stdin: Some(WasiStdin { inner: stdin }),
stdout: Some(WasiStdout { inner: stdout }),
stderr: Some(WasiStderr { inner: stderr }),
handle: Box::pin(handle),
}
}
pub fn spawn(self) -> SpawnHandle {
let inner = tokio::spawn(self);
SpawnHandle { inner }
}
}
impl Future for WasiProcess {
type Output = Result<(), RuntimeError>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
self.handle.as_mut().poll(cx)
}
}
#[derive(Debug)]
pub struct SpawnHandle {
inner: tokio::task::JoinHandle<<WasiProcess as Future>::Output>,
}
impl Future for SpawnHandle {
type Output = Result<(), SpawnError>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
Pin::new(&mut self.inner)
.poll(cx)
.map(|res| res.map_err(SpawnError::Join)?.map_err(SpawnError::Wasi))
}
}
#[derive(Debug)]
pub enum SpawnError {
Wasi(RuntimeError),
Join(tokio::task::JoinError),
}
impl fmt::Display for SpawnError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
Self::Wasi(w) => write!(f, "runtime wasi/wasm error: {}", w),
Self::Join(j) => write!(f, "error while joining the tokio task: {}", j),
}
}
}
impl std::error::Error for SpawnError {}