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|
use std::io::{self};
use std::os::unix::prelude::{AsRawFd, CommandExt, FromRawFd};
use std::pin::Pin;
use std::process::{abort, Command};
use std::task::{Context, Poll};
use eyre::{bail, Result};
use futures::Future;
use nix::pty::{forkpty, Winsize};
use nix::sys::termios::Termios;
use nix::sys::wait::{waitpid, WaitPidFlag, WaitStatus};
use nix::unistd::{ForkResult, Pid};
use tokio::fs::File;
use tokio::io::{AsyncRead, AsyncWrite};
use tokio::signal::unix::{signal, Signal, SignalKind};
use tokio::task::spawn_blocking;
mod ioctl {
use super::Winsize;
use libc::TIOCSWINSZ;
use nix::ioctl_write_ptr_bad;
ioctl_write_ptr_bad!(tiocswinsz, TIOCSWINSZ, Winsize);
}
async fn asyncify<F, T>(f: F) -> Result<T>
where
F: FnOnce() -> Result<T> + Send + 'static,
T: Send + 'static,
{
match spawn_blocking(f).await {
Ok(res) => res,
Err(_) => bail!("background task failed",),
}
}
pub struct Child {
pub tty: File,
pub pid: Pid,
}
pub struct ChildHandle {
pub tty: File,
}
pub struct WaitPid {
pid: Pid,
signal: Signal,
}
impl WaitPid {
pub fn new(pid: Pid) -> Self {
Self {
pid,
signal: signal(SignalKind::child()).unwrap(),
}
}
}
impl Future for WaitPid {
type Output = nix::Result<WaitStatus>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let _ = self.signal.poll_recv(cx);
match waitpid(self.pid, Some(WaitPidFlag::WNOHANG)) {
Ok(WaitStatus::StillAlive) => Poll::Pending,
result => Poll::Ready(result),
}
}
}
impl Child {
pub async fn handle(&self) -> io::Result<ChildHandle> {
Ok(ChildHandle {
tty: self.tty.try_clone().await?,
})
}
}
impl ChildHandle {
pub async fn resize_window(&mut self, winsize: Winsize) -> Result<()> {
let fd = self.tty.as_raw_fd();
asyncify(move || unsafe {
ioctl::tiocswinsz(fd, &winsize as *const Winsize)?;
Ok(())
})
.await
}
}
pub async fn spawn(
mut cmd: Command,
winsize: Option<Winsize>,
termios: Option<Termios>,
) -> Result<Child> {
asyncify(move || unsafe {
let res = forkpty(winsize.as_ref(), termios.as_ref())?;
match res.fork_result {
ForkResult::Parent { child } => Ok(Child {
pid: child,
tty: File::from_raw_fd(res.master),
}),
ForkResult::Child => {
cmd.exec();
abort();
}
}
})
.await
}
impl AsyncRead for Child {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut tokio::io::ReadBuf<'_>,
) -> Poll<io::Result<()>> {
Pin::new(&mut self.tty).poll_read(cx, buf)
}
}
impl AsyncWrite for Child {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize, io::Error>> {
Pin::new(&mut self.tty).poll_write(cx, buf)
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), io::Error>> {
Pin::new(&mut self.tty).poll_flush(cx)
}
fn poll_shutdown(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<(), io::Error>> {
Pin::new(&mut self.tty).poll_shutdown(cx)
}
}
impl AsyncRead for ChildHandle {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut tokio::io::ReadBuf<'_>,
) -> Poll<io::Result<()>> {
Pin::new(&mut self.tty).poll_read(cx, buf)
}
}
impl AsyncWrite for ChildHandle {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize, io::Error>> {
Pin::new(&mut self.tty).poll_write(cx, buf)
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), io::Error>> {
Pin::new(&mut self.tty).poll_flush(cx)
}
fn poll_shutdown(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<(), io::Error>> {
Pin::new(&mut self.tty).poll_shutdown(cx)
}
}
|
