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Rollup merge of #129754 - alexcrichton:fix-wasi-long-sleep, r=workingjubilee

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wasi: Fix sleeping for `Duration::MAX`

This commit fixes an assert in the WASI-specific implementation of thread sleep to ensure that sleeping for a very large period of time blocks instead of panicking. This can come up when testing programs that sleep "forever", for example.

I'll note that I haven't included a test for this since it's sort of difficult to test. I've tested this locally though that long sleeps do indeed block and short sleeps still only sleep for a short amount of time.
This commit is contained in:
Matthias Krüger 2024-08-31 10:08:59 +02:00 committed by GitHub
commit 25e3b66410
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1 changed files with 29 additions and 28 deletions
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57
library/std/src/sys/pal/wasi/thread.rs
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@ -136,36 +136,37 @@ pub fn set_name(_name: &CStr) {
}
pub fn sleep(dur: Duration) {
let nanos = dur.as_nanos();
assert!(nanos <= u64::MAX as u128);
let mut nanos = dur.as_nanos();
while nanos > 0 {
const USERDATA: wasi::Userdata = 0x0123_45678;
const USERDATA: wasi::Userdata = 0x0123_45678;
let clock = wasi::SubscriptionClock {
id: wasi::CLOCKID_MONOTONIC,
timeout: u64::try_from(nanos).unwrap_or(u64::MAX),
precision: 0,
flags: 0,
};
nanos -= u128::from(clock.timeout);
let clock = wasi::SubscriptionClock {
id: wasi::CLOCKID_MONOTONIC,
timeout: nanos as u64,
precision: 0,
flags: 0,
};
let in_ = wasi::Subscription {
userdata: USERDATA,
u: wasi::SubscriptionU { tag: 0, u: wasi::SubscriptionUU { clock } },
};
unsafe {
let mut event: wasi::Event = mem::zeroed();
let res = wasi::poll_oneoff(&in_, &mut event, 1);
match (res, event) {
(
Ok(1),
wasi::Event {
userdata: USERDATA,
error: wasi::ERRNO_SUCCESS,
type_: wasi::EVENTTYPE_CLOCK,
..
},
) => {}
_ => panic!("thread::sleep(): unexpected result of poll_oneoff"),
let in_ = wasi::Subscription {
userdata: USERDATA,
u: wasi::SubscriptionU { tag: 0, u: wasi::SubscriptionUU { clock } },
};
unsafe {
let mut event: wasi::Event = mem::zeroed();
let res = wasi::poll_oneoff(&in_, &mut event, 1);
match (res, event) {
(
Ok(1),
wasi::Event {
userdata: USERDATA,
error: wasi::ERRNO_SUCCESS,
type_: wasi::EVENTTYPE_CLOCK,
..
},
) => {}
_ => panic!("thread::sleep(): unexpected result of poll_oneoff"),
}
}
}
}