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wry/src/utils/buffd/buf_in.rs
2022-01-02 15:13:33 +01:00

105 lines
3.5 KiB
Rust

use crate::async_engine::AsyncFd;
use crate::utils::buffd::{BufFdError, BUF_SIZE, CMSG_BUF_SIZE, MAX_IN_FD};
use std::collections::VecDeque;
use std::mem::MaybeUninit;
use uapi::{c, Errno, OwnedFd, Pod};
pub struct BufFdIn {
fd: AsyncFd,
in_fd: VecDeque<OwnedFd>,
in_buf: Box<[MaybeUninit<u8>; BUF_SIZE]>,
in_cmsg_buf: Box<[MaybeUninit<u8>; CMSG_BUF_SIZE]>,
in_left: usize,
in_right: usize,
}
impl BufFdIn {
pub fn new(fd: AsyncFd) -> Self {
Self {
fd,
in_fd: Default::default(),
in_buf: Box::new([MaybeUninit::uninit(); BUF_SIZE]),
in_cmsg_buf: Box::new([MaybeUninit::uninit(); CMSG_BUF_SIZE]),
in_left: 0,
in_right: 0,
}
}
pub async fn read_full<T: Pod + ?Sized>(&mut self, buf: &mut T) -> Result<(), BufFdError> {
let bytes = unsafe { uapi::as_maybe_uninit_bytes_mut2(buf) };
let mut offset = 0;
while offset < bytes.len() {
if self.read_full_(bytes, &mut offset)? {
self.fd.readable().await?;
}
}
Ok(())
}
fn read_full_(
&mut self,
bytes: &mut [MaybeUninit<u8>],
offset: &mut usize,
) -> Result<bool, BufFdError> {
let num_bytes = (bytes.len() - *offset).min(self.in_right - self.in_left);
if num_bytes > 0 {
let left = self.in_left % BUF_SIZE;
let right = (self.in_left + num_bytes) % BUF_SIZE;
if left < right {
bytes[*offset..*offset + num_bytes].copy_from_slice(&self.in_buf[left..right]);
} else {
bytes[*offset..*offset + (BUF_SIZE - left)].copy_from_slice(&self.in_buf[left..]);
bytes[*offset + (BUF_SIZE - left)..*offset + num_bytes]
.copy_from_slice(&self.in_buf[..right]);
}
self.in_left += num_bytes;
*offset += num_bytes;
}
if *offset == bytes.len() {
return Ok(false);
}
let left = self.in_left % BUF_SIZE;
let right = self.in_right % BUF_SIZE;
let mut iov = if right < left {
[&mut self.in_buf[right..left], &mut []]
} else {
let (l, r) = self.in_buf.split_at_mut(right);
[r, &mut l[..left]]
};
let mut hdr = uapi::MsghdrMut {
iov: &mut iov[..],
control: Some(&mut self.in_cmsg_buf[..]),
name: uapi::sockaddr_none_mut(),
flags: 0,
};
let (iov, _, mut cmsg) = match uapi::recvmsg(self.fd.raw(), &mut hdr, c::MSG_DONTWAIT) {
Ok((iov, _, _)) if iov.is_empty() => return Err(BufFdError::Closed),
Ok(v) => v,
Err(Errno(c::EAGAIN)) => return Ok(true),
Err(e) => return Err(BufFdError::Io(e.into())),
};
self.in_right += iov.len();
while cmsg.len() > 0 {
let (_, hdr, data) = match uapi::cmsg_read(&mut cmsg) {
Ok(m) => m,
Err(e) => return Err(BufFdError::Io(e.into())),
};
if (hdr.cmsg_level, hdr.cmsg_type) == (c::SOL_SOCKET, c::SCM_RIGHTS) {
self.in_fd.extend(uapi::pod_iter(data).unwrap());
}
}
if self.in_fd.len() > MAX_IN_FD {
return Err(BufFdError::TooManyFds);
}
Ok(false)
}
pub fn get_fd(&mut self) -> Result<OwnedFd, BufFdError> {
match self.in_fd.pop_front() {
Some(f) => Ok(f),
None => Err(BufFdError::NoFd),
}
}
}