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use async_io::Async;
use std::{
io,
os::unix::{
io::{AsRawFd, FromRawFd, RawFd},
net::UnixStream,
},
};
use nix::{
cmsg_space,
sys::{
socket::{recvmsg, sendmsg, ControlMessage, ControlMessageOwned, MsgFlags},
uio::IoVec,
},
};
use crate::{utils::FDS_MAX, OwnedFd};
pub trait Socket {
const SUPPORTS_FD_PASSING: bool;
fn recvmsg(&mut self, buffer: &mut [u8]) -> io::Result<(usize, Vec<OwnedFd>)>;
fn sendmsg(&mut self, buffer: &[u8], fds: &[RawFd]) -> io::Result<usize>;
fn close(&self) -> io::Result<()>;
}
impl Socket for UnixStream {
const SUPPORTS_FD_PASSING: bool = true;
fn recvmsg(&mut self, buffer: &mut [u8]) -> io::Result<(usize, Vec<OwnedFd>)> {
let iov = [IoVec::from_mut_slice(buffer)];
let mut cmsgspace = cmsg_space!([RawFd; FDS_MAX]);
match recvmsg(
self.as_raw_fd(),
&iov,
Some(&mut cmsgspace),
MsgFlags::empty(),
) {
Ok(msg) => {
let mut fds = vec![];
for cmsg in msg.cmsgs() {
if let ControlMessageOwned::ScmRights(fd) = cmsg {
fds.extend(fd.iter().map(|&f| unsafe { OwnedFd::from_raw_fd(f) }));
} else {
return Err(io::Error::new(
io::ErrorKind::InvalidData,
"unexpected CMSG kind",
));
}
}
Ok((msg.bytes, fds))
}
Err(nix::Error::Sys(e)) => Err(e.into()),
_ => Err(io::Error::new(io::ErrorKind::Other, "unhandled nix error")),
}
}
fn sendmsg(&mut self, buffer: &[u8], fds: &[RawFd]) -> io::Result<usize> {
let cmsg = if !fds.is_empty() {
vec![ControlMessage::ScmRights(fds)]
} else {
vec![]
};
let iov = [IoVec::from_slice(buffer)];
match sendmsg(self.as_raw_fd(), &iov, &cmsg, MsgFlags::empty(), None) {
Ok(0) => Err(io::Error::new(
io::ErrorKind::WriteZero,
"failed to write to buffer",
)),
Ok(n) => Ok(n),
Err(nix::Error::Sys(e)) => Err(e.into()),
_ => Err(io::Error::new(io::ErrorKind::Other, "unhandled nix error")),
}
}
fn close(&self) -> io::Result<()> {
self.shutdown(std::net::Shutdown::Both)
}
}
impl<S> Socket for Async<S>
where
S: Socket,
{
const SUPPORTS_FD_PASSING: bool = true;
fn recvmsg(&mut self, buffer: &mut [u8]) -> io::Result<(usize, Vec<OwnedFd>)> {
self.get_mut().recvmsg(buffer)
}
fn sendmsg(&mut self, buffer: &[u8], fds: &[RawFd]) -> io::Result<usize> {
self.get_mut().sendmsg(buffer, fds)
}
fn close(&self) -> io::Result<()> {
self.get_ref().close()
}
}