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use wasmer_wasix_types::wasi::{EpollCtl, EpollEvent, EpollEventCtl, SubscriptionClock, Userdata};
use super::*;
use crate::{
WasiInodes,
fs::{InodeValFilePollGuard, InodeValFilePollGuardJoin},
os::epoll::register_epoll_handler,
state::PollEventSet,
syscalls::*,
};
/// ### `epoll_ctl()`
/// Modifies an epoll interest list
/// Output:
/// - `Fd fd`
/// The new file handle that is used to modify or wait on the interest list
#[instrument(level = "trace", skip_all, fields(timeout_ms = field::Empty, fd_guards = field::Empty, seen = field::Empty, fd), ret)]
pub fn epoll_ctl<M: MemorySize + 'static>(
mut ctx: FunctionEnvMut<'_, WasiEnv>,
epfd: WasiFd,
op: EpollCtl,
fd: WasiFd,
event_ref: WasmPtr<EpollEvent<M>, M>,
) -> Result<Errno, WasiError> {
WasiEnv::do_pending_operations(&mut ctx)?;
let env = ctx.data();
let memory = unsafe { env.memory_view(&ctx) };
let event = if event_ref.offset() != M::ZERO {
Some(wasi_try_mem_ok!(event_ref.read(&memory)))
} else {
None
};
let event_ctl = event.map(|evt| EpollEventCtl {
events: evt.events,
ptr: evt.data.ptr.into(),
fd: evt.data.fd,
data1: evt.data.data1,
data2: evt.data.data2,
});
wasi_try_ok!(epoll_ctl_internal(
&mut ctx,
epfd,
op,
fd,
event_ctl.as_ref()
)?);
let env = ctx.data();
#[cfg(feature = "journal")]
if env.enable_journal {
JournalEffector::save_epoll_ctl(&mut ctx, epfd, op, fd, event_ctl).map_err(|err| {
tracing::error!("failed to save epoll_create event - {}", err);
WasiError::Exit(ExitCode::from(Errno::Fault))
})?;
}
Ok(Errno::Success)
}
pub(crate) fn epoll_ctl_internal(
ctx: &mut FunctionEnvMut<'_, WasiEnv>,
epfd: WasiFd,
op: EpollCtl,
fd: WasiFd,
event_ctl: Option<&EpollEventCtl>,
) -> Result<Result<(), Errno>, WasiError> {
let env = ctx.data();
let fd_entry = wasi_try_ok_ok!(env.state.fs.get_fd(epfd));
let mut inode_guard = fd_entry.inode.read();
match inode_guard.deref() {
Kind::Epoll { state } => {
let res = match op {
EpollCtl::Add => {
let Some(event) = event_ctl else {
return Ok(Err(Errno::Inval));
};
let (epoll_fd, sub_state) = match state.prepare_add(fd, event) {
Ok(v) => v,
Err(err) => return Ok(Err(err)),
};
match register_epoll_handler(
&env.state,
&epoll_fd,
state.clone(),
sub_state.clone(),
) {
Ok(fd_guard) => {
if let Some(fd_guard) = fd_guard {
sub_state.add_join(fd_guard);
}
Ok(())
}
Err(err) => {
state.rollback_registration(fd, None);
Err(err)
}
}
}
EpollCtl::Mod => {
let Some(event) = event_ctl else {
return Ok(Err(Errno::Inval));
};
let (epoll_fd, sub_state, old_subscription) = match state.prepare_mod(fd, event)
{
Ok(v) => v,
Err(err) => return Ok(Err(err)),
};
// Detach the previous generation before installing the new
// handler so dropping old guards cannot remove the new one.
old_subscription.detach_joins();
match register_epoll_handler(
&env.state,
&epoll_fd,
state.clone(),
sub_state.clone(),
) {
Ok(fd_guard) => {
if let Some(fd_guard) = fd_guard {
sub_state.add_join(fd_guard);
}
Ok(())
}
Err(err) => {
state.rollback_registration(fd, Some(old_subscription.clone()));
let old_epoll_fd = old_subscription.fd_meta();
match register_epoll_handler(
&env.state,
&old_epoll_fd,
state.clone(),
old_subscription.clone(),
) {
Ok(fd_guard) => {
if let Some(fd_guard) = fd_guard {
old_subscription.add_join(fd_guard);
}
}
Err(reinstall_err) => {
// Do not leave a restored subscription without handlers.
state.rollback_registration(fd, None);
tracing::warn!(
fd,
?err,
?reinstall_err,
"failed to reinstall previous epoll handler after MOD failure"
);
return Ok(Err(reinstall_err));
}
}
Err(err)
}
}
}
EpollCtl::Del => state.apply_del(fd),
EpollCtl::Unknown => Err(Errno::Inval),
};
Ok(res)
}
_ => Ok(Err(Errno::Inval)),
}
}