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wry/src/utils/buffd/buf_out.rs
2022-01-07 15:08:31 +01:00

126 lines
4.1 KiB
Rust

use crate::async_engine::AsyncFd;
use crate::utils::buffd::{BufFdError, BUF_SIZE, CMSG_BUF_SIZE};
use futures::{select, FutureExt};
use std::collections::VecDeque;
use std::mem::MaybeUninit;
use std::rc::Rc;
use std::slice;
use uapi::{c, Errno, OwnedFd};
pub(super) const OUT_BUF_SIZE: usize = 2 * BUF_SIZE;
pub(super) struct MsgFds {
pub(super) pos: usize,
pub(super) fds: Vec<Rc<OwnedFd>>,
}
pub struct BufFdOut {
fd: AsyncFd,
pub(super) out_pos: usize,
pub(super) out_buf: *mut [MaybeUninit<u8>; OUT_BUF_SIZE],
pub(super) fds: VecDeque<MsgFds>,
fd_ids: Vec<i32>,
cmsg_buf: Box<[MaybeUninit<u8>; CMSG_BUF_SIZE]>,
}
impl BufFdOut {
pub fn new(fd: AsyncFd) -> Self {
Self {
fd,
out_pos: 0,
out_buf: Box::into_raw(Box::new([MaybeUninit::<u32>::uninit(); OUT_BUF_SIZE / 4])) as _,
fds: Default::default(),
fd_ids: vec![],
cmsg_buf: Box::new([MaybeUninit::uninit(); CMSG_BUF_SIZE]),
}
}
pub fn write(&mut self, bytes: &[MaybeUninit<u8>]) {
if bytes.len() > OUT_BUF_SIZE - self.out_pos {
panic!("Out buffer overflow");
}
unsafe {
(*self.out_buf)[self.out_pos..self.out_pos + bytes.len()].copy_from_slice(bytes);
}
self.out_pos += bytes.len();
}
pub fn needs_flush(&self) -> bool {
self.out_pos > BUF_SIZE
}
pub async fn flush(&mut self) -> Result<(), BufFdError> {
let mut timeout = None;
let mut pos = 0;
while pos < self.out_pos {
if self.flush_sync(&mut pos)? {
if timeout.is_none() {
timeout = Some(self.fd.eng().timeout(5000)?.fuse());
}
select! {
_ = timeout.as_mut().unwrap() => return Err(BufFdError::Timeout),
res = self.fd.writable().fuse() => res?,
}
}
}
self.out_pos = 0;
Ok(())
}
fn flush_sync(&mut self, pos: &mut usize) -> Result<bool, BufFdError> {
while *pos < self.out_pos {
let mut buf = unsafe { &(*self.out_buf)[*pos..self.out_pos] };
let mut cmsg_len = 0;
let mut fds_opt = None;
{
let mut f = self.fds.front().map(|f| f.pos);
if f == Some(*pos) {
let fds = self.fds.pop_front().unwrap();
self.fd_ids.clear();
self.fd_ids.extend(fds.fds.iter().map(|f| f.raw()));
let hdr = c::cmsghdr {
cmsg_len: 0,
cmsg_level: c::SOL_SOCKET,
cmsg_type: c::SCM_RIGHTS,
};
let mut cmsg_buf = &mut self.cmsg_buf[..];
cmsg_len = uapi::cmsg_write(&mut cmsg_buf, hdr, &self.fd_ids[..]).unwrap();
fds_opt = Some(fds);
f = self.fds.front().map(|f| f.pos)
}
if let Some(next_pos) = f {
buf = &buf[..next_pos - *pos];
}
}
let hdr = uapi::Msghdr {
iov: slice::from_ref(&buf),
control: Some(&self.cmsg_buf[..cmsg_len]),
name: uapi::sockaddr_none_ref(),
};
let bytes_sent =
match uapi::sendmsg(self.fd.raw(), &hdr, c::MSG_DONTWAIT | c::MSG_NOSIGNAL) {
Ok(b) => b,
Err(Errno(c::EAGAIN)) => {
if let Some(fds) = fds_opt {
self.fds.push_front(fds);
}
return Ok(true);
}
Err(Errno(c::ECONNRESET)) => return Err(BufFdError::Closed),
Err(e) => return Err(BufFdError::Io(e.into())),
};
*pos += bytes_sent;
}
Ok(false)
}
}
impl Drop for BufFdOut {
fn drop(&mut self) {
unsafe {
Box::from_raw(self.out_buf as *mut [MaybeUninit<u32>; OUT_BUF_SIZE / 4]);
}
}
}