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use crate::error::*;
use std::os::unix::io::{AsRawFd as _, FromRawFd as _};
use std::os::unix::process::CommandExt as _;
pub trait Command {
fn spawn_pty(&mut self, size: Option<crate::pty::Size>) -> Result<Child>;
}
impl Command for std::process::Command {
fn spawn_pty(&mut self, size: Option<crate::pty::Size>) -> Result<Child> {
let pty = crate::pty::Pty::new()?;
let pts = pty.pts(size)?;
let pt_fd = pty.pt().as_raw_fd();
let pts_fd = pts.as_raw_fd();
let stdin = nix::unistd::dup(pts_fd).map_err(Error::SpawnNix)?;
let stdout = nix::unistd::dup(pts_fd).map_err(Error::SpawnNix)?;
let stderr = nix::unistd::dup(pts_fd).map_err(Error::SpawnNix)?;
// safe because the fds are valid (otherwise pty.pts() or dup() would
// have returned an Err and we would have exited early) and are not
// owned by any other structure (since dup() returns a fresh copy of
// the file descriptor), allowing from_raw_fd to take ownership of it.
self.stdin(unsafe { std::process::Stdio::from_raw_fd(stdin) })
.stdout(unsafe { std::process::Stdio::from_raw_fd(stdout) })
.stderr(unsafe { std::process::Stdio::from_raw_fd(stderr) });
// safe because the only thing this function does is call close(),
// which is an async-signal-safe function
unsafe {
self.pre_exec(move || {
// in the parent, destructors will handle closing these file
// descriptors (other than pt, used by the parent to
// communicate with the child) when the function ends, but in
// the child, we end by calling exec(), which doesn't call
// destructors.
// XXX unwrap
nix::unistd::close(pt_fd)
.map_err(|e| e.as_errno().unwrap())?;
nix::unistd::close(pts_fd)
.map_err(|e| e.as_errno().unwrap())?;
// at this point, stdin/stdout/stderr have already been
// reopened as fds 0/1/2 in the child, so we can (and should)
// close the originals
nix::unistd::close(stdin)
.map_err(|e| e.as_errno().unwrap())?;
nix::unistd::close(stdout)
.map_err(|e| e.as_errno().unwrap())?;
nix::unistd::close(stderr)
.map_err(|e| e.as_errno().unwrap())?;
Ok(())
});
}
let child = self.spawn().map_err(Error::Spawn)?;
Ok(Child { child, pty })
}
}
pub struct Child {
child: std::process::Child,
pty: crate::pty::Pty,
}
impl Child {
pub fn pty(&self) -> &std::fs::File {
self.pty.pt()
}
}
impl std::ops::Deref for Child {
type Target = std::process::Child;
fn deref(&self) -> &Self::Target {
&self.child
}
}
impl std::ops::DerefMut for Child {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.child
}
}
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