1 use crate::io::{self, IoSlice, IoSliceMut};
2 use libc::{self /*, c_int apparently not used? */};
4 use crate::sync::atomic::{AtomicBool};
5 use crate::sys::fd::FileDesc;
6 use crate::sys::{cvt, cvt_r};
8 pub struct AnonPipe(FileDesc);
10 pub fn anon_pipe() -> io::Result<(AnonPipe, AnonPipe)> {
11 static INVALID: AtomicBool = AtomicBool::new(false);
14 cvt(unsafe { libc::pipe(fds.as_mut_ptr()) })?;
16 let fd0 = FileDesc::new(fds[0]);
17 let fd1 = FileDesc::new(fds[1]);
20 Ok((AnonPipe(fd0), AnonPipe(fd1)))
24 pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
27 pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
28 self.0.read_vectored(bufs)
31 pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
35 pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
36 self.0.write_vectored(bufs)
39 pub fn fd(&self) -> &FileDesc { &self.0 }
40 pub fn into_fd(self) -> FileDesc { self.0 }
41 pub fn diverge(&self) -> ! {
46 pub fn read2(p1: AnonPipe,
49 v2: &mut Vec<u8>) -> io::Result<()> {
51 // Set both pipes into nonblocking mode as we're gonna be reading from both
52 // in the `select` loop below, and we wouldn't want one to block the other!
53 let p1 = p1.into_fd();
54 let p2 = p2.into_fd();
55 p1.set_nonblocking_pipe(true)?;
56 p2.set_nonblocking_pipe(true)?;
58 let mut fds: [libc::pollfd; 2] = unsafe { mem::zeroed() };
60 fds[0].events = libc::POLLIN;
62 fds[1].events = libc::POLLIN;
64 // wait for either pipe to become readable using `poll`
65 cvt_r(|| unsafe { libc::poll(fds.as_mut_ptr(), 2, -1) })?;
67 if fds[0].revents != 0 && read(&p1, v1)? {
68 p2.set_nonblocking_pipe(false)?;
69 return p2.read_to_end(v2).map(|_| ());
71 if fds[1].revents != 0 && read(&p2, v2)? {
72 p1.set_nonblocking_pipe(false)?;
73 return p1.read_to_end(v1).map(|_| ());
77 // Read as much as we can from each pipe, ignoring EWOULDBLOCK or
78 // EAGAIN. If we hit EOF, then this will happen because the underlying
79 // reader will return Ok(0), in which case we'll see `Ok` ourselves. In
80 // this case we flip the other fd back into blocking mode and read
81 // whatever's leftover on that file descriptor.
82 fn read(fd: &FileDesc, dst: &mut Vec<u8>) -> Result<bool, io::Error> {
83 match fd.read_to_end(dst) {
86 if e.raw_os_error() == Some(libc::EWOULDBLOCK) ||
87 e.raw_os_error() == Some(libc::EAGAIN) {