src/libstd/sys/vxworks/pipe.rs

   1 use crate::io::{self, IoSlice, IoSliceMut};
   2 use crate::mem;
   3 use crate::sync::atomic::AtomicBool;
   4 use crate::sys::fd::FileDesc;
   5 use crate::sys::{cvt, cvt_r};
   6 use libc::{self /*, c_int apparently not used? */};
   7
   8 pub struct AnonPipe(FileDesc);
   9
  10 pub fn anon_pipe() -> io::Result<(AnonPipe, AnonPipe)> {
  11     static INVALID: AtomicBool = AtomicBool::new(false);
  12
  13     let mut fds = [0; 2];
  14     cvt(unsafe { libc::pipe(fds.as_mut_ptr()) })?;
  15
  16     let fd0 = FileDesc::new(fds[0]);
  17     let fd1 = FileDesc::new(fds[1]);
  18     fd0.set_cloexec()?;
  19     fd1.set_cloexec()?;
  20     Ok((AnonPipe(fd0), AnonPipe(fd1)))
  21 }
  22
  23 impl AnonPipe {
  24     pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
  25         self.0.read(buf)
  26     }
  27     pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
  28         self.0.read_vectored(bufs)
  29     }
  30
  31     pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
  32         self.0.write(buf)
  33     }
  34
  35     pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
  36         self.0.write_vectored(bufs)
  37     }
  38
  39     pub fn fd(&self) -> &FileDesc {
  40         &self.0
  41     }
  42     pub fn into_fd(self) -> FileDesc {
  43         self.0
  44     }
  45     pub fn diverge(&self) -> ! {
  46         panic!()
  47     }
  48 }
  49
  50 pub fn read2(p1: AnonPipe, v1: &mut Vec<u8>, p2: AnonPipe, 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)?;
  57
  58     let mut fds: [libc::pollfd; 2] = unsafe { mem::zeroed() };
  59     fds[0].fd = p1.raw();
  60     fds[0].events = libc::POLLIN;
  61     fds[1].fd = p2.raw();
  62     fds[1].events = libc::POLLIN;
  63     loop {
  64         // wait for either pipe to become readable using `poll`
  65         cvt_r(|| unsafe { libc::poll(fds.as_mut_ptr(), 2, -1) })?;
  66
  67         if fds[0].revents != 0 && read(&p1, v1)? {
  68             p2.set_nonblocking_pipe(false)?;
  69             return p2.read_to_end(v2).map(|_| ());
  70         }
  71         if fds[1].revents != 0 && read(&p2, v2)? {
  72             p1.set_nonblocking_pipe(false)?;
  73             return p1.read_to_end(v1).map(|_| ());
  74         }
  75     }
  76
  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) {
  84             Ok(_) => Ok(true),
  85             Err(e) => {
  86                 if e.raw_os_error() == Some(libc::EWOULDBLOCK)
  87                     || e.raw_os_error() == Some(libc::EAGAIN)
  88                 {
  89                     Ok(false)
  90                 } else {
  91                     Err(e)
  92                 }
  93             }
  94         }
  95     }
  96 }