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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
commit36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/mio/src/sys/unix/pipe.rs
parentInitial commit. (diff)
downloadfirefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz
firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/mio/src/sys/unix/pipe.rs')
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+//! Unix pipe.
+//!
+//! See the [`new`] function for documentation.
+
+use std::fs::File;
+use std::io::{self, IoSlice, IoSliceMut, Read, Write};
+use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
+use std::process::{ChildStderr, ChildStdin, ChildStdout};
+
+use crate::io_source::IoSource;
+use crate::{event, Interest, Registry, Token};
+
+/// Create a new non-blocking Unix pipe.
+///
+/// This is a wrapper around Unix's [`pipe(2)`] system call and can be used as
+/// inter-process or thread communication channel.
+///
+/// This channel may be created before forking the process and then one end used
+/// in each process, e.g. the parent process has the sending end to send command
+/// to the child process.
+///
+/// [`pipe(2)`]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/pipe.html
+///
+/// # Events
+///
+/// The [`Sender`] can be registered with [`WRITABLE`] interest to receive
+/// [writable events], the [`Receiver`] with [`READABLE`] interest. Once data is
+/// written to the `Sender` the `Receiver` will receive an [readable event].
+///
+/// In addition to those events, events will also be generated if the other side
+/// is dropped. To check if the `Sender` is dropped you'll need to check
+/// [`is_read_closed`] on events for the `Receiver`, if it returns true the
+/// `Sender` is dropped. On the `Sender` end check [`is_write_closed`], if it
+/// returns true the `Receiver` was dropped. Also see the second example below.
+///
+/// [`WRITABLE`]: Interest::WRITABLE
+/// [writable events]: event::Event::is_writable
+/// [`READABLE`]: Interest::READABLE
+/// [readable event]: event::Event::is_readable
+/// [`is_read_closed`]: event::Event::is_read_closed
+/// [`is_write_closed`]: event::Event::is_write_closed
+///
+/// # Deregistering
+///
+/// Both `Sender` and `Receiver` will deregister themselves when dropped,
+/// **iff** the file descriptors are not duplicated (via [`dup(2)`]).
+///
+/// [`dup(2)`]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/dup.html
+///
+/// # Examples
+///
+/// Simple example that writes data into the sending end and read it from the
+/// receiving end.
+///
+/// ```
+/// use std::io::{self, Read, Write};
+///
+/// use mio::{Poll, Events, Interest, Token};
+/// use mio::unix::pipe;
+///
+/// // Unique tokens for the two ends of the channel.
+/// const PIPE_RECV: Token = Token(0);
+/// const PIPE_SEND: Token = Token(1);
+///
+/// # fn main() -> io::Result<()> {
+/// // Create our `Poll` instance and the `Events` container.
+/// let mut poll = Poll::new()?;
+/// let mut events = Events::with_capacity(8);
+///
+/// // Create a new pipe.
+/// let (mut sender, mut receiver) = pipe::new()?;
+///
+/// // Register both ends of the channel.
+/// poll.registry().register(&mut receiver, PIPE_RECV, Interest::READABLE)?;
+/// poll.registry().register(&mut sender, PIPE_SEND, Interest::WRITABLE)?;
+///
+/// const MSG: &[u8; 11] = b"Hello world";
+///
+/// loop {
+/// poll.poll(&mut events, None)?;
+///
+/// for event in events.iter() {
+/// match event.token() {
+/// PIPE_SEND => sender.write(MSG)
+/// .and_then(|n| if n != MSG.len() {
+/// // We'll consider a short write an error in this
+/// // example. NOTE: we can't use `write_all` with
+/// // non-blocking I/O.
+/// Err(io::ErrorKind::WriteZero.into())
+/// } else {
+/// Ok(())
+/// })?,
+/// PIPE_RECV => {
+/// let mut buf = [0; 11];
+/// let n = receiver.read(&mut buf)?;
+/// println!("received: {:?}", &buf[0..n]);
+/// assert_eq!(n, MSG.len());
+/// assert_eq!(&buf, &*MSG);
+/// return Ok(());
+/// },
+/// _ => unreachable!(),
+/// }
+/// }
+/// }
+/// # }
+/// ```
+///
+/// Example that receives an event once the `Sender` is dropped.
+///
+/// ```
+/// # use std::io;
+/// #
+/// # use mio::{Poll, Events, Interest, Token};
+/// # use mio::unix::pipe;
+/// #
+/// # const PIPE_RECV: Token = Token(0);
+/// # const PIPE_SEND: Token = Token(1);
+/// #
+/// # fn main() -> io::Result<()> {
+/// // Same setup as in the example above.
+/// let mut poll = Poll::new()?;
+/// let mut events = Events::with_capacity(8);
+///
+/// let (mut sender, mut receiver) = pipe::new()?;
+///
+/// poll.registry().register(&mut receiver, PIPE_RECV, Interest::READABLE)?;
+/// poll.registry().register(&mut sender, PIPE_SEND, Interest::WRITABLE)?;
+///
+/// // Drop the sender.
+/// drop(sender);
+///
+/// poll.poll(&mut events, None)?;
+///
+/// for event in events.iter() {
+/// match event.token() {
+/// PIPE_RECV if event.is_read_closed() => {
+/// // Detected that the sender was dropped.
+/// println!("Sender dropped!");
+/// return Ok(());
+/// },
+/// _ => unreachable!(),
+/// }
+/// }
+/// # unreachable!();
+/// # }
+/// ```
+pub fn new() -> io::Result<(Sender, Receiver)> {
+ let mut fds: [RawFd; 2] = [-1, -1];
+
+ #[cfg(any(
+ target_os = "android",
+ target_os = "dragonfly",
+ target_os = "freebsd",
+ target_os = "linux",
+ target_os = "netbsd",
+ target_os = "openbsd",
+ target_os = "illumos",
+ ))]
+ unsafe {
+ if libc::pipe2(fds.as_mut_ptr(), libc::O_CLOEXEC | libc::O_NONBLOCK) != 0 {
+ return Err(io::Error::last_os_error());
+ }
+ }
+
+ #[cfg(any(target_os = "ios", target_os = "macos"))]
+ unsafe {
+ // For platforms that don't have `pipe2(2)` we need to manually set the
+ // correct flags on the file descriptor.
+ if libc::pipe(fds.as_mut_ptr()) != 0 {
+ return Err(io::Error::last_os_error());
+ }
+
+ for fd in &fds {
+ if libc::fcntl(*fd, libc::F_SETFL, libc::O_NONBLOCK) != 0
+ || libc::fcntl(*fd, libc::F_SETFD, libc::FD_CLOEXEC) != 0
+ {
+ let err = io::Error::last_os_error();
+ // Don't leak file descriptors. Can't handle error though.
+ let _ = libc::close(fds[0]);
+ let _ = libc::close(fds[1]);
+ return Err(err);
+ }
+ }
+ }
+
+ #[cfg(not(any(
+ target_os = "android",
+ target_os = "dragonfly",
+ target_os = "freebsd",
+ target_os = "linux",
+ target_os = "netbsd",
+ target_os = "openbsd",
+ target_os = "ios",
+ target_os = "macos",
+ target_os = "illumos",
+ )))]
+ compile_error!("unsupported target for `mio::unix::pipe`");
+
+ // Safety: we just initialised the `fds` above.
+ let r = unsafe { Receiver::from_raw_fd(fds[0]) };
+ let w = unsafe { Sender::from_raw_fd(fds[1]) };
+ Ok((w, r))
+}
+
+/// Sending end of an Unix pipe.
+///
+/// See [`new`] for documentation, including examples.
+#[derive(Debug)]
+pub struct Sender {
+ inner: IoSource<File>,
+}
+
+impl Sender {
+ /// Set the `Sender` into or out of non-blocking mode.
+ pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
+ set_nonblocking(self.inner.as_raw_fd(), nonblocking)
+ }
+}
+
+impl event::Source for Sender {
+ fn register(
+ &mut self,
+ registry: &Registry,
+ token: Token,
+ interests: Interest,
+ ) -> io::Result<()> {
+ self.inner.register(registry, token, interests)
+ }
+
+ fn reregister(
+ &mut self,
+ registry: &Registry,
+ token: Token,
+ interests: Interest,
+ ) -> io::Result<()> {
+ self.inner.reregister(registry, token, interests)
+ }
+
+ fn deregister(&mut self, registry: &Registry) -> io::Result<()> {
+ self.inner.deregister(registry)
+ }
+}
+
+impl Write for Sender {
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ self.inner.do_io(|sender| (&*sender).write(buf))
+ }
+
+ fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+ self.inner.do_io(|sender| (&*sender).write_vectored(bufs))
+ }
+
+ fn flush(&mut self) -> io::Result<()> {
+ self.inner.do_io(|sender| (&*sender).flush())
+ }
+}
+
+impl Write for &Sender {
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ self.inner.do_io(|sender| (&*sender).write(buf))
+ }
+
+ fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+ self.inner.do_io(|sender| (&*sender).write_vectored(bufs))
+ }
+
+ fn flush(&mut self) -> io::Result<()> {
+ self.inner.do_io(|sender| (&*sender).flush())
+ }
+}
+
+/// # Notes
+///
+/// The underlying pipe is **not** set to non-blocking.
+impl From<ChildStdin> for Sender {
+ fn from(stdin: ChildStdin) -> Sender {
+ // Safety: `ChildStdin` is guaranteed to be a valid file descriptor.
+ unsafe { Sender::from_raw_fd(stdin.into_raw_fd()) }
+ }
+}
+
+impl FromRawFd for Sender {
+ unsafe fn from_raw_fd(fd: RawFd) -> Sender {
+ Sender {
+ inner: IoSource::new(File::from_raw_fd(fd)),
+ }
+ }
+}
+
+impl AsRawFd for Sender {
+ fn as_raw_fd(&self) -> RawFd {
+ self.inner.as_raw_fd()
+ }
+}
+
+impl IntoRawFd for Sender {
+ fn into_raw_fd(self) -> RawFd {
+ self.inner.into_inner().into_raw_fd()
+ }
+}
+
+/// Receiving end of an Unix pipe.
+///
+/// See [`new`] for documentation, including examples.
+#[derive(Debug)]
+pub struct Receiver {
+ inner: IoSource<File>,
+}
+
+impl Receiver {
+ /// Set the `Receiver` into or out of non-blocking mode.
+ pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
+ set_nonblocking(self.inner.as_raw_fd(), nonblocking)
+ }
+}
+
+impl event::Source for Receiver {
+ fn register(
+ &mut self,
+ registry: &Registry,
+ token: Token,
+ interests: Interest,
+ ) -> io::Result<()> {
+ self.inner.register(registry, token, interests)
+ }
+
+ fn reregister(
+ &mut self,
+ registry: &Registry,
+ token: Token,
+ interests: Interest,
+ ) -> io::Result<()> {
+ self.inner.reregister(registry, token, interests)
+ }
+
+ fn deregister(&mut self, registry: &Registry) -> io::Result<()> {
+ self.inner.deregister(registry)
+ }
+}
+
+impl Read for Receiver {
+ fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+ self.inner.do_io(|sender| (&*sender).read(buf))
+ }
+
+ fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
+ self.inner.do_io(|sender| (&*sender).read_vectored(bufs))
+ }
+}
+
+impl Read for &Receiver {
+ fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+ self.inner.do_io(|sender| (&*sender).read(buf))
+ }
+
+ fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
+ self.inner.do_io(|sender| (&*sender).read_vectored(bufs))
+ }
+}
+
+/// # Notes
+///
+/// The underlying pipe is **not** set to non-blocking.
+impl From<ChildStdout> for Receiver {
+ fn from(stdout: ChildStdout) -> Receiver {
+ // Safety: `ChildStdout` is guaranteed to be a valid file descriptor.
+ unsafe { Receiver::from_raw_fd(stdout.into_raw_fd()) }
+ }
+}
+
+/// # Notes
+///
+/// The underlying pipe is **not** set to non-blocking.
+impl From<ChildStderr> for Receiver {
+ fn from(stderr: ChildStderr) -> Receiver {
+ // Safety: `ChildStderr` is guaranteed to be a valid file descriptor.
+ unsafe { Receiver::from_raw_fd(stderr.into_raw_fd()) }
+ }
+}
+
+impl FromRawFd for Receiver {
+ unsafe fn from_raw_fd(fd: RawFd) -> Receiver {
+ Receiver {
+ inner: IoSource::new(File::from_raw_fd(fd)),
+ }
+ }
+}
+
+impl AsRawFd for Receiver {
+ fn as_raw_fd(&self) -> RawFd {
+ self.inner.as_raw_fd()
+ }
+}
+
+impl IntoRawFd for Receiver {
+ fn into_raw_fd(self) -> RawFd {
+ self.inner.into_inner().into_raw_fd()
+ }
+}
+
+#[cfg(not(target_os = "illumos"))]
+fn set_nonblocking(fd: RawFd, nonblocking: bool) -> io::Result<()> {
+ let value = nonblocking as libc::c_int;
+ if unsafe { libc::ioctl(fd, libc::FIONBIO, &value) } == -1 {
+ Err(io::Error::last_os_error())
+ } else {
+ Ok(())
+ }
+}
+
+#[cfg(target_os = "illumos")]
+fn set_nonblocking(fd: RawFd, nonblocking: bool) -> io::Result<()> {
+ let flags = unsafe { libc::fcntl(fd, libc::F_GETFL) };
+ if flags < 0 {
+ return Err(io::Error::last_os_error());
+ }
+
+ let nflags = if nonblocking {
+ flags | libc::O_NONBLOCK
+ } else {
+ flags & !libc::O_NONBLOCK
+ };
+
+ if flags != nflags {
+ if unsafe { libc::fcntl(fd, libc::F_SETFL, nflags) } < 0 {
+ return Err(io::Error::last_os_error());
+ }
+ }
+
+ Ok(())
+}