1 use crate::io::{self, IoSlice, IoSliceMut};
3 use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
4 use crate::sys::fd::FileDesc;
5 use crate::sys::{cvt, cvt_r};
6 use crate::sys_common::IntoInner;
8 ////////////////////////////////////////////////////////////////////////////////
10 ////////////////////////////////////////////////////////////////////////////////
12 pub struct AnonPipe(FileDesc);
14 pub fn anon_pipe() -> io::Result<(AnonPipe, AnonPipe)> {
17 // The only known way right now to create atomically set the CLOEXEC flag is
18 // to use the `pipe2` syscall. This was added to Linux in 2.6.27, glibc 2.9
19 // and musl 0.9.3, and some other targets also have it.
22 target_os = "dragonfly",
23 target_os = "freebsd",
26 target_os = "openbsd",
30 cvt(libc::pipe2(fds.as_mut_ptr(), libc::O_CLOEXEC))?;
31 Ok((AnonPipe(FileDesc::from_raw_fd(fds[0])), AnonPipe(FileDesc::from_raw_fd(fds[1]))))
35 cvt(libc::pipe(fds.as_mut_ptr()))?;
37 let fd0 = FileDesc::from_raw_fd(fds[0]);
38 let fd1 = FileDesc::from_raw_fd(fds[1]);
41 Ok((AnonPipe(fd0), AnonPipe(fd1)))
48 pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
52 pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
53 self.0.read_vectored(bufs)
57 pub fn is_read_vectored(&self) -> bool {
58 self.0.is_read_vectored()
61 pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
65 pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
66 self.0.write_vectored(bufs)
70 pub fn is_write_vectored(&self) -> bool {
71 self.0.is_write_vectored()
75 impl IntoInner<FileDesc> for AnonPipe {
76 fn into_inner(self) -> FileDesc {
81 pub fn read2(p1: AnonPipe, v1: &mut Vec<u8>, p2: AnonPipe, v2: &mut Vec<u8>) -> io::Result<()> {
82 // Set both pipes into nonblocking mode as we're gonna be reading from both
83 // in the `select` loop below, and we wouldn't want one to block the other!
84 let p1 = p1.into_inner();
85 let p2 = p2.into_inner();
86 p1.set_nonblocking(true)?;
87 p2.set_nonblocking(true)?;
89 let mut fds: [libc::pollfd; 2] = unsafe { mem::zeroed() };
90 fds[0].fd = p1.as_raw_fd();
91 fds[0].events = libc::POLLIN;
92 fds[1].fd = p2.as_raw_fd();
93 fds[1].events = libc::POLLIN;
95 // wait for either pipe to become readable using `poll`
96 cvt_r(|| unsafe { libc::poll(fds.as_mut_ptr(), 2, -1) })?;
98 if fds[0].revents != 0 && read(&p1, v1)? {
99 p2.set_nonblocking(false)?;
100 return p2.read_to_end(v2).map(drop);
102 if fds[1].revents != 0 && read(&p2, v2)? {
103 p1.set_nonblocking(false)?;
104 return p1.read_to_end(v1).map(drop);
108 // Read as much as we can from each pipe, ignoring EWOULDBLOCK or
109 // EAGAIN. If we hit EOF, then this will happen because the underlying
110 // reader will return Ok(0), in which case we'll see `Ok` ourselves. In
111 // this case we flip the other fd back into blocking mode and read
112 // whatever's leftover on that file descriptor.
113 fn read(fd: &FileDesc, dst: &mut Vec<u8>) -> Result<bool, io::Error> {
114 match fd.read_to_end(dst) {
117 if e.raw_os_error() == Some(libc::EWOULDBLOCK)
118 || e.raw_os_error() == Some(libc::EAGAIN)
129 impl AsRawFd for AnonPipe {
130 fn as_raw_fd(&self) -> RawFd {
135 impl AsFd for AnonPipe {
136 fn as_fd(&self) -> BorrowedFd<'_> {
141 impl IntoRawFd for AnonPipe {
142 fn into_raw_fd(self) -> RawFd {
147 impl FromRawFd for AnonPipe {
148 unsafe fn from_raw_fd(raw_fd: RawFd) -> Self {
149 Self(FromRawFd::from_raw_fd(raw_fd))