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wasi-c2: implement a synchronous poll_oneoff in terms of yanix

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doesnt work on unix yet! also breaks all the rules about using the
cap-std family instead of rawfds! but this is cool and im happy with it
This commit is contained in:
Pat Hickey
2021-01-14 17:43:53 -08:00
parent b84c4d7488
commit 7f7a0be938
8 changed files with 172 additions and 60 deletions
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16
Cargo.lock generated
View File

@@ -2472,6 +2472,7 @@ dependencies = [
"thiserror",
"tracing",
"wiggle",
"yanix 0.22.0 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
@@ -2501,7 +2502,7 @@ dependencies = [
"wiggle",
"winapi",
"winx 0.22.0",
"yanix",
"yanix 0.22.0",
]
[[package]]
@@ -3111,6 +3112,19 @@ dependencies = [
"tracing",
]
[[package]]
name = "yanix"
version = "0.22.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "0504d76a87b9e77f1057d419a51acb4344b9e14eaf37dde22cf1fd0ec28901db"
dependencies = [
"bitflags",
"cfg-if 1.0.0",
"filetime",
"libc",
"tracing",
]
[[package]]
name = "z3"
version = "0.7.1"

1
crates/wasi-c2/Cargo.toml
View File

@@ -32,6 +32,7 @@ cap-rand = "0.9"
fs-set-times = "0.2.2"
cfg-if = "1"
bitflags = "1.2"
yanix = "0.22"
[badges]
maintenance = { status = "actively-developed" }

6
crates/wasi-c2/src/ctx.rs
View File

@@ -75,7 +75,7 @@ impl WasiCtxBuilder {
self.0.insert_file(
0,
f,
FileCaps::READ, // XXX fixme: more rights are ok, but this is read-only
FileCaps::READ | FileCaps::POLL_READWRITE, // XXX fixme: more rights are ok, but this is read-only
);
self
}
@@ -84,7 +84,7 @@ impl WasiCtxBuilder {
self.0.insert_file(
1,
f,
FileCaps::WRITE, // XXX fixme: more rights are ok, but this is append only
FileCaps::WRITE | FileCaps::POLL_READWRITE, // XXX fixme: more rights are ok, but this is append only
);
self
}
@@ -93,7 +93,7 @@ impl WasiCtxBuilder {
self.0.insert_file(
2,
f,
FileCaps::WRITE, // XXX fixme: more rights are ok, but this is append only
FileCaps::WRITE | FileCaps::POLL_READWRITE, // XXX fixme: more rights are ok, but this is append only
);
self
}

24
crates/wasi-c2/src/sched.rs
View File

@@ -58,7 +58,7 @@ impl<'a> Poll<'a> {
}
pub fn subscribe_write(&mut self, file: Ref<'a, dyn WasiFile>, ud: Userdata) {
self.subs
.push((Subscription::Read(RwSubscription::new(file)), ud));
.push((Subscription::Write(RwSubscription::new(file)), ud));
}
pub fn results(self) -> Vec<(SubscriptionResult, Userdata)> {
self.subs
@@ -66,7 +66,25 @@ impl<'a> Poll<'a> {
.filter_map(|(s, ud)| SubscriptionResult::from_subscription(s).map(|r| (r, ud)))
.collect()
}
pub fn subscriptions(&'a self) -> impl Iterator<Item = &Subscription<'a>> {
self.subs.iter().map(|(s, _ud)| s)
pub fn is_empty(&self) -> bool {
self.subs.is_empty()
}
pub fn earliest_system_timer(&'a self) -> Option<&SystemTimerSubscription<'a>> {
let mut subs = self
.subs
.iter()
.filter_map(|(s, _ud)| match s {
Subscription::SystemTimer(t) => Some(t),
_ => None,
})
.collect::<Vec<&SystemTimerSubscription<'a>>>();
subs.sort_by(|a, b| a.deadline.cmp(&b.deadline));
subs.into_iter().next() // First element is earliest
}
pub fn rw_subscriptions(&'a self) -> impl Iterator<Item = &Subscription<'a>> {
self.subs.iter().filter_map(|(s, _ud)| match s {
Subscription::Read { .. } | Subscription::Write { .. } => Some(s),
_ => None,
})
}
}

9
crates/wasi-c2/src/sched/subscription.rs
View File

@@ -41,12 +41,11 @@ pub struct SystemTimerSubscription<'a> {
}
impl<'a> SystemTimerSubscription<'a> {
pub fn now(&self) -> SystemTime {
self.clock.now(self.precision)
}
pub fn result(&self) -> Option<Result<(), Error>> {
if self
.deadline
.duration_since(self.clock.now(self.precision))
.is_ok()
{
if self.now().duration_since(self.deadline).is_ok() {
Some(Ok(()))
} else {
None

170
crates/wasi-c2/src/sched/sync.rs
View File

@@ -1,55 +1,131 @@
use crate::file::WasiFile;
use crate::sched::subscription::{RwSubscription, Subscription, SystemTimerSubscription};
use crate::sched::{Poll, WasiSched};
use crate::Error;
use std::any::Any;
use std::ops::Deref;
#[cfg(unix)]
use std::os::unix::io::{AsRawFd, RawFd};
pub use unix::*;
#[derive(Default)]
pub struct SyncSched {}
#[cfg(unix)]
mod unix {
use crate::file::WasiFile;
use crate::sched::subscription::{RwEventFlags, Subscription};
use crate::sched::{Poll, WasiSched};
use crate::Error;
use cap_std::time::Duration;
use std::convert::TryInto;
use std::ops::Deref;
use std::os::unix::io::{AsRawFd, RawFd};
use yanix::poll::{PollFd, PollFlags};
impl WasiSched for SyncSched {
fn poll_oneoff(&self, poll: &Poll) -> Result<(), Error> {
for s in poll.subscriptions() {
match s {
Subscription::Read(f) | Subscription::Write(f) => {
let raw_fd = wasi_file_raw_fd(f.file.deref()).ok_or(Error::Inval)?;
todo!()
}
Subscription::SystemTimer(t) => {
todo!()
#[derive(Default)]
pub struct SyncSched {}
impl WasiSched for SyncSched {
fn poll_oneoff<'a>(&self, poll: &'a Poll<'a>) -> Result<(), Error> {
if poll.is_empty() {
return Ok(());
}
let mut pollfds = Vec::new();
let timeout = poll.earliest_system_timer();
for s in poll.rw_subscriptions() {
match s {
Subscription::Read(f) => {
let raw_fd = wasi_file_raw_fd(f.file.deref()).ok_or(Error::Inval)?;
pollfds.push(unsafe { PollFd::new(raw_fd, PollFlags::POLLIN) });
}
Subscription::Write(f) => {
let raw_fd = wasi_file_raw_fd(f.file.deref()).ok_or(Error::Inval)?;
pollfds.push(unsafe { PollFd::new(raw_fd, PollFlags::POLLOUT) });
}
Subscription::SystemTimer { .. } => unreachable!(),
}
}
}
Ok(())
}
fn sched_yield(&self) -> Result<(), Error> {
std::thread::yield_now();
Ok(())
}
}
fn wasi_file_raw_fd(f: &dyn WasiFile) -> Option<RawFd> {
let a = f.as_any();
if a.is::<cap_std::fs::File>() {
Some(a.downcast_ref::<cap_std::fs::File>().unwrap().as_raw_fd())
} else if a.is::<crate::stdio::Stdin>() {
Some(a.downcast_ref::<crate::stdio::Stdin>().unwrap().as_raw_fd())
} else if a.is::<crate::stdio::Stdout>() {
Some(
a.downcast_ref::<crate::stdio::Stdout>()
.unwrap()
.as_raw_fd(),
)
} else if a.is::<crate::stdio::Stderr>() {
Some(
a.downcast_ref::<crate::stdio::Stderr>()
.unwrap()
.as_raw_fd(),
)
} else {
None
let ready = loop {
let poll_timeout = if let Some(t) = timeout {
let duration = t
.deadline
.duration_since(t.clock.now(t.precision))
.unwrap_or(Duration::from_secs(0));
(duration.as_millis() + 1) // XXX try always rounding up?
.try_into()
.map_err(|_| Error::Overflow)?
} else {
libc::c_int::max_value()
};
tracing::debug!(
poll_timeout = tracing::field::debug(poll_timeout),
poll_fds = tracing::field::debug(&pollfds),
"poll"
);
match yanix::poll::poll(&mut pollfds, poll_timeout) {
Ok(ready) => break ready,
Err(_) => {
let last_err = std::io::Error::last_os_error();
if last_err.raw_os_error().unwrap() == libc::EINTR {
continue;
} else {
return Err(last_err.into());
}
}
}
};
if ready > 0 {
for (rwsub, pollfd) in poll.rw_subscriptions().zip(pollfds.into_iter()) {
if let Some(revents) = pollfd.revents() {
let (nbytes, rwsub) = match rwsub {
Subscription::Read(sub) => {
(1, sub)
// XXX FIXME: query_nbytes in wasi-common/src/sys/poll.rs
// uses metadata.len - tell to calculate for regular files,
// ioctl(fd, FIONREAD) for large files
}
Subscription::Write(sub) => (0, sub),
_ => unreachable!(),
};
if revents.contains(PollFlags::POLLNVAL) {
rwsub.error(Error::Badf);
} else if revents.contains(PollFlags::POLLERR) {
rwsub.error(Error::Io);
} else if revents.contains(PollFlags::POLLHUP) {
rwsub.complete(nbytes, RwEventFlags::HANGUP);
} else {
rwsub.complete(nbytes, RwEventFlags::empty());
};
}
}
} else {
timeout
.expect("timed out")
.result()
.expect("timer deadline is past")
.unwrap()
}
Ok(())
}
fn sched_yield(&self) -> Result<(), Error> {
std::thread::yield_now();
Ok(())
}
}
fn wasi_file_raw_fd(f: &dyn WasiFile) -> Option<RawFd> {
let a = f.as_any();
if a.is::<cap_std::fs::File>() {
Some(a.downcast_ref::<cap_std::fs::File>().unwrap().as_raw_fd())
} else if a.is::<crate::stdio::Stdin>() {
Some(a.downcast_ref::<crate::stdio::Stdin>().unwrap().as_raw_fd())
} else if a.is::<crate::stdio::Stdout>() {
Some(
a.downcast_ref::<crate::stdio::Stdout>()
.unwrap()
.as_raw_fd(),
)
} else if a.is::<crate::stdio::Stderr>() {
Some(
a.downcast_ref::<crate::stdio::Stderr>()
.unwrap()
.as_raw_fd(),
)
} else {
None
}
}
}

4
crates/wasi-c2/src/snapshots/preview_1.rs
View File

@@ -891,6 +891,10 @@ impl<'a> wasi_snapshot_preview1::WasiSnapshotPreview1 for WasiCtx {
events: &GuestPtr<types::Event>,
nsubscriptions: types::Size,
) -> Result<types::Size, Error> {
if nsubscriptions == 0 {
return Err(Error::Inval);
}
use cap_std::time::{Duration, SystemClock};
let table = self.table();
let mut poll = Poll::new();

2
crates/wasi-c2/src/table.rs
View File

@@ -62,7 +62,7 @@ impl Table {
Err(Error::Exist) // Does exist, but borrowed
}
} else {
Err(Error::Exist) // Does not exist
Err(Error::Badf) // Does not exist
}
}