| use crate::io::{self, IoSlice, IoSliceMut}; |
| use crate::mem; |
| use crate::sync::atomic::AtomicBool; |
| use crate::sys::fd::FileDesc; |
| use crate::sys::{cvt, cvt_r}; |
| use libc::{self /*, c_int apparently not used? */}; |
| |
| pub struct AnonPipe(FileDesc); |
| |
| pub fn anon_pipe() -> io::Result<(AnonPipe, AnonPipe)> { |
| static INVALID: AtomicBool = AtomicBool::new(false); |
| |
| let mut fds = [0; 2]; |
| cvt(unsafe { libc::pipe(fds.as_mut_ptr()) })?; |
| |
| let fd0 = FileDesc::new(fds[0]); |
| let fd1 = FileDesc::new(fds[1]); |
| fd0.set_cloexec()?; |
| fd1.set_cloexec()?; |
| Ok((AnonPipe(fd0), AnonPipe(fd1))) |
| } |
| |
| impl AnonPipe { |
| pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> { |
| self.0.read(buf) |
| } |
| |
| pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> { |
| self.0.read_vectored(bufs) |
| } |
| |
| #[inline] |
| pub fn is_read_vectored(&self) -> bool { |
| self.0.is_read_vectored() |
| } |
| |
| pub fn write(&self, buf: &[u8]) -> io::Result<usize> { |
| self.0.write(buf) |
| } |
| |
| pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { |
| self.0.write_vectored(bufs) |
| } |
| |
| #[inline] |
| pub fn is_write_vectored(&self) -> bool { |
| self.0.is_write_vectored() |
| } |
| |
| pub fn fd(&self) -> &FileDesc { |
| &self.0 |
| } |
| pub fn into_fd(self) -> FileDesc { |
| self.0 |
| } |
| pub fn diverge(&self) -> ! { |
| panic!() |
| } |
| } |
| |
| pub fn read2(p1: AnonPipe, v1: &mut Vec<u8>, p2: AnonPipe, v2: &mut Vec<u8>) -> io::Result<()> { |
| // Set both pipes into nonblocking mode as we're gonna be reading from both |
| // in the `select` loop below, and we wouldn't want one to block the other! |
| let p1 = p1.into_fd(); |
| let p2 = p2.into_fd(); |
| p1.set_nonblocking_pipe(true)?; |
| p2.set_nonblocking_pipe(true)?; |
| |
| let mut fds: [libc::pollfd; 2] = unsafe { mem::zeroed() }; |
| fds[0].fd = p1.raw(); |
| fds[0].events = libc::POLLIN; |
| fds[1].fd = p2.raw(); |
| fds[1].events = libc::POLLIN; |
| loop { |
| // wait for either pipe to become readable using `poll` |
| cvt_r(|| unsafe { libc::poll(fds.as_mut_ptr(), 2, -1) })?; |
| |
| if fds[0].revents != 0 && read(&p1, v1)? { |
| p2.set_nonblocking_pipe(false)?; |
| return p2.read_to_end(v2).map(drop); |
| } |
| if fds[1].revents != 0 && read(&p2, v2)? { |
| p1.set_nonblocking_pipe(false)?; |
| return p1.read_to_end(v1).map(drop); |
| } |
| } |
| |
| // Read as much as we can from each pipe, ignoring EWOULDBLOCK or |
| // EAGAIN. If we hit EOF, then this will happen because the underlying |
| // reader will return Ok(0), in which case we'll see `Ok` ourselves. In |
| // this case we flip the other fd back into blocking mode and read |
| // whatever's leftover on that file descriptor. |
| fn read(fd: &FileDesc, dst: &mut Vec<u8>) -> Result<bool, io::Error> { |
| match fd.read_to_end(dst) { |
| Ok(_) => Ok(true), |
| Err(e) => { |
| if e.raw_os_error() == Some(libc::EWOULDBLOCK) |
| || e.raw_os_error() == Some(libc::EAGAIN) |
| { |
| Ok(false) |
| } else { |
| Err(e) |
| } |
| } |
| } |
| } |
| } |