Files
wasmtime/crates/wasi-common/src/sys/unix/hostcalls_impl/misc.rs
2019-11-12 09:22:19 -06:00

222 lines
8.4 KiB
Rust

#![allow(non_camel_case_types)]
#![allow(unused_unsafe)]
use crate::hostcalls_impl::{ClockEventData, FdEventData};
use crate::sys::host_impl;
use crate::{wasi, Error, Result};
use nix::libc::{self, c_int};
use std::mem::MaybeUninit;
fn wasi_clock_id_to_unix(clock_id: wasi::__wasi_clockid_t) -> Result<libc::clockid_t> {
// convert the supported clocks to the libc types, or return EINVAL
match clock_id {
wasi::__WASI_CLOCK_REALTIME => Ok(libc::CLOCK_REALTIME),
wasi::__WASI_CLOCK_MONOTONIC => Ok(libc::CLOCK_MONOTONIC),
wasi::__WASI_CLOCK_PROCESS_CPUTIME_ID => Ok(libc::CLOCK_PROCESS_CPUTIME_ID),
wasi::__WASI_CLOCK_THREAD_CPUTIME_ID => Ok(libc::CLOCK_THREAD_CPUTIME_ID),
_ => Err(Error::EINVAL),
}
}
pub(crate) fn clock_res_get(clock_id: wasi::__wasi_clockid_t) -> Result<wasi::__wasi_timestamp_t> {
let clock_id = wasi_clock_id_to_unix(clock_id)?;
// no `nix` wrapper for clock_getres, so we do it ourselves
let mut timespec = MaybeUninit::<libc::timespec>::uninit();
let res = unsafe { libc::clock_getres(clock_id, timespec.as_mut_ptr()) };
if res != 0 {
return Err(host_impl::errno_from_nix(nix::errno::Errno::last()));
}
let timespec = unsafe { timespec.assume_init() };
// convert to nanoseconds, returning EOVERFLOW in case of overflow;
// this is freelancing a bit from the spec but seems like it'll
// be an unusual situation to hit
(timespec.tv_sec as wasi::__wasi_timestamp_t)
.checked_mul(1_000_000_000)
.and_then(|sec_ns| sec_ns.checked_add(timespec.tv_nsec as wasi::__wasi_timestamp_t))
.map_or(Err(Error::EOVERFLOW), |resolution| {
// a supported clock can never return zero; this case will probably never get hit, but
// make sure we follow the spec
if resolution == 0 {
Err(Error::EINVAL)
} else {
Ok(resolution)
}
})
}
pub(crate) fn clock_time_get(clock_id: wasi::__wasi_clockid_t) -> Result<wasi::__wasi_timestamp_t> {
let clock_id = wasi_clock_id_to_unix(clock_id)?;
// no `nix` wrapper for clock_getres, so we do it ourselves
let mut timespec = MaybeUninit::<libc::timespec>::uninit();
let res = unsafe { libc::clock_gettime(clock_id, timespec.as_mut_ptr()) };
if res != 0 {
return Err(host_impl::errno_from_nix(nix::errno::Errno::last()));
}
let timespec = unsafe { timespec.assume_init() };
// convert to nanoseconds, returning EOVERFLOW in case of overflow; this is freelancing a bit
// from the spec but seems like it'll be an unusual situation to hit
(timespec.tv_sec as wasi::__wasi_timestamp_t)
.checked_mul(1_000_000_000)
.and_then(|sec_ns| sec_ns.checked_add(timespec.tv_nsec as wasi::__wasi_timestamp_t))
.map_or(Err(Error::EOVERFLOW), Ok)
}
pub(crate) fn poll_oneoff(
timeout: Option<ClockEventData>,
fd_events: Vec<FdEventData>,
events: &mut Vec<wasi::__wasi_event_t>,
) -> Result<()> {
use nix::{
errno::Errno,
poll::{poll, PollFd, PollFlags},
};
use std::{convert::TryInto, os::unix::prelude::AsRawFd};
if fd_events.is_empty() && timeout.is_none() {
return Ok(());
}
let mut poll_fds: Vec<_> = fd_events
.iter()
.map(|event| {
let mut flags = PollFlags::empty();
match event.r#type {
wasi::__WASI_EVENTTYPE_FD_READ => flags.insert(PollFlags::POLLIN),
wasi::__WASI_EVENTTYPE_FD_WRITE => flags.insert(PollFlags::POLLOUT),
// An event on a file descriptor can currently only be of type FD_READ or FD_WRITE
// Nothing else has been defined in the specification, and these are also the only two
// events we filtered before. If we get something else here, the code has a serious bug.
_ => unreachable!(),
};
PollFd::new(event.descriptor.as_raw_fd(), flags)
})
.collect();
let poll_timeout = timeout.map_or(-1, |timeout| {
let delay = timeout.delay / 1_000_000; // poll syscall requires delay to expressed in milliseconds
delay.try_into().unwrap_or(c_int::max_value())
});
log::debug!("poll_oneoff poll_timeout = {:?}", poll_timeout);
let ready = loop {
match poll(&mut poll_fds, poll_timeout) {
Err(_) => {
if Errno::last() == Errno::EINTR {
continue;
}
return Err(host_impl::errno_from_nix(Errno::last()));
}
Ok(ready) => break ready as usize,
}
};
Ok(if ready == 0 {
poll_oneoff_handle_timeout_event(timeout.expect("timeout should not be None"), events)
} else {
let ready_events = fd_events.into_iter().zip(poll_fds.into_iter()).take(ready);
poll_oneoff_handle_fd_event(ready_events, events)?
})
}
// define the `fionread()` function, equivalent to `ioctl(fd, FIONREAD, *bytes)`
nix::ioctl_read_bad!(fionread, nix::libc::FIONREAD, c_int);
fn poll_oneoff_handle_timeout_event(
timeout: ClockEventData,
events: &mut Vec<wasi::__wasi_event_t>,
) {
events.push(wasi::__wasi_event_t {
userdata: timeout.userdata,
r#type: wasi::__WASI_EVENTTYPE_CLOCK,
error: wasi::__WASI_ESUCCESS,
u: wasi::__wasi_event_u {
fd_readwrite: wasi::__wasi_event_fd_readwrite_t {
nbytes: 0,
flags: 0,
},
},
});
}
fn poll_oneoff_handle_fd_event<'a>(
ready_events: impl Iterator<Item = (FdEventData<'a>, nix::poll::PollFd)>,
events: &mut Vec<wasi::__wasi_event_t>,
) -> Result<()> {
use nix::poll::PollFlags;
use std::{convert::TryInto, os::unix::prelude::AsRawFd};
for (fd_event, poll_fd) in ready_events {
log::debug!("poll_oneoff_handle_fd_event fd_event = {:?}", fd_event);
log::debug!("poll_oneoff_handle_fd_event poll_fd = {:?}", poll_fd);
let revents = match poll_fd.revents() {
Some(revents) => revents,
None => continue,
};
log::debug!("poll_oneoff_handle_fd_event revents = {:?}", revents);
let mut nbytes = 0;
if fd_event.r#type == wasi::__WASI_EVENTTYPE_FD_READ {
let _ = unsafe { fionread(fd_event.descriptor.as_raw_fd(), &mut nbytes) };
}
let output_event = if revents.contains(PollFlags::POLLNVAL) {
wasi::__wasi_event_t {
userdata: fd_event.userdata,
r#type: fd_event.r#type,
error: wasi::__WASI_EBADF,
u: wasi::__wasi_event_u {
fd_readwrite: wasi::__wasi_event_fd_readwrite_t {
nbytes: 0,
flags: wasi::__WASI_EVENT_FD_READWRITE_HANGUP,
},
},
}
} else if revents.contains(PollFlags::POLLERR) {
wasi::__wasi_event_t {
userdata: fd_event.userdata,
r#type: fd_event.r#type,
error: wasi::__WASI_EIO,
u: wasi::__wasi_event_u {
fd_readwrite: wasi::__wasi_event_fd_readwrite_t {
nbytes: 0,
flags: wasi::__WASI_EVENT_FD_READWRITE_HANGUP,
},
},
}
} else if revents.contains(PollFlags::POLLHUP) {
wasi::__wasi_event_t {
userdata: fd_event.userdata,
r#type: fd_event.r#type,
error: wasi::__WASI_ESUCCESS,
u: wasi::__wasi_event_u {
fd_readwrite: wasi::__wasi_event_fd_readwrite_t {
nbytes: 0,
flags: wasi::__WASI_EVENT_FD_READWRITE_HANGUP,
},
},
}
} else if revents.contains(PollFlags::POLLIN) | revents.contains(PollFlags::POLLOUT) {
wasi::__wasi_event_t {
userdata: fd_event.userdata,
r#type: fd_event.r#type,
error: wasi::__WASI_ESUCCESS,
u: wasi::__wasi_event_u {
fd_readwrite: wasi::__wasi_event_fd_readwrite_t {
nbytes: nbytes.try_into()?,
flags: 0,
},
},
}
} else {
continue;
};
events.push(output_event);
}
Ok(())
}