Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 233 insertions, 0 deletions

diff --git a/third_party/rust/nix/src/poll.rs b/third_party/rust/nix/src/poll.rs
new file mode 100644
index 0000000000..9181bf7f30
--- /dev/null
+++ b/third_party/rust/nix/src/poll.rs
@@ -0,0 +1,233 @@
+//! Wait for events to trigger on specific file descriptors
+use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd};
+
+use crate::errno::Errno;
+use crate::Result;
+
+/// This is a wrapper around `libc::pollfd`.
+///
+/// It's meant to be used as an argument to the [`poll`](fn.poll.html) and
+/// [`ppoll`](fn.ppoll.html) functions to specify the events of interest
+/// for a specific file descriptor.
+///
+/// After a call to `poll` or `ppoll`, the events that occurred can be
+/// retrieved by calling [`revents()`](#method.revents) on the `PollFd`.
+#[repr(transparent)]
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+pub struct PollFd<'fd> {
+    pollfd: libc::pollfd,
+    _fd: std::marker::PhantomData<BorrowedFd<'fd>>,
+}
+
+impl<'fd> PollFd<'fd> {
+    /// Creates a new `PollFd` specifying the events of interest
+    /// for a given file descriptor.
+    //
+    // Different from other I/O-safe interfaces, here, we have to take `AsFd`
+    // by reference to prevent the case where the `fd` is closed but it is
+    // still in use. For example:
+    //
+    // ```rust
+    // let (reader, _) = pipe().unwrap();
+    //
+    // // If `PollFd::new()` takes `AsFd` by value, then `reader` will be consumed,
+    // // but the file descriptor of `reader` will still be in use.
+    // let pollfd = PollFd::new(reader, flag);
+    //
+    // // Do something with `pollfd`, which uses the CLOSED fd.
+    // ```
+    pub fn new<Fd: AsFd>(fd: &'fd Fd, events: PollFlags) -> PollFd<'fd> {
+        PollFd {
+            pollfd: libc::pollfd {
+                fd: fd.as_fd().as_raw_fd(),
+                events: events.bits(),
+                revents: PollFlags::empty().bits(),
+            },
+            _fd: std::marker::PhantomData,
+        }
+    }
+
+    /// Returns the events that occurred in the last call to `poll` or `ppoll`.  Will only return
+    /// `None` if the kernel provides status flags that Nix does not know about.
+    pub fn revents(self) -> Option<PollFlags> {
+        PollFlags::from_bits(self.pollfd.revents)
+    }
+
+    /// Returns if any of the events of interest occured in the last call to `poll` or `ppoll`. Will
+    /// only return `None` if the kernel provides status flags that Nix does not know about.
+    ///
+    /// Equivalent to `x.revents()? != PollFlags::empty()`.
+    ///
+    /// This is marginally more efficient than [`PollFd::all`].
+    pub fn any(self) -> Option<bool> {
+        Some(self.revents()? != PollFlags::empty())
+    }
+
+    /// Returns if all the events of interest occured in the last call to `poll` or `ppoll`. Will
+    /// only return `None` if the kernel provides status flags that Nix does not know about.
+    ///
+    /// Equivalent to `x.revents()? & x.events() == x.events()`.
+    ///
+    /// This is marginally less efficient than [`PollFd::any`].
+    pub fn all(self) -> Option<bool> {
+        Some(self.revents()? & self.events() == self.events())
+    }
+
+    /// The events of interest for this `PollFd`.
+    pub fn events(self) -> PollFlags {
+        PollFlags::from_bits(self.pollfd.events).unwrap()
+    }
+
+    /// Modify the events of interest for this `PollFd`.
+    pub fn set_events(&mut self, events: PollFlags) {
+        self.pollfd.events = events.bits();
+    }
+}
+
+impl<'fd> AsFd for PollFd<'fd> {
+    fn as_fd(&self) -> BorrowedFd<'_> {
+        // Safety:
+        //
+        // BorrowedFd::borrow_raw(RawFd) requires that the raw fd being passed
+        // must remain open for the duration of the returned BorrowedFd, this is
+        // guaranteed as the returned BorrowedFd has the lifetime parameter same
+        // as `self`:
+        // "fn as_fd<'self>(&'self self) -> BorrowedFd<'self>"
+        // which means that `self` (PollFd) is guaranteed to outlive the returned
+        // BorrowedFd. (Lifetime: PollFd > BorrowedFd)
+        //
+        // And the lifetime parameter of PollFd::new(fd, ...) ensures that `fd`
+        // (an owned file descriptor) must outlive the returned PollFd:
+        // "pub fn new<Fd: AsFd>(fd: &'fd Fd, events: PollFlags) -> PollFd<'fd>"
+        // (Lifetime: Owned fd > PollFd)
+        //
+        // With two above relationships, we can conclude that the `Owned file
+        // descriptor` will outlive the returned BorrowedFd,
+        // (Lifetime: Owned fd > BorrowedFd)
+        // i.e., the raw fd being passed will remain valid for the lifetime of
+        // the returned BorrowedFd.
+        unsafe { BorrowedFd::borrow_raw(self.pollfd.fd) }
+    }
+}
+
+libc_bitflags! {
+    /// These flags define the different events that can be monitored by `poll` and `ppoll`
+    pub struct PollFlags: libc::c_short {
+        /// There is data to read.
+        POLLIN;
+        /// There is some exceptional condition on the file descriptor.
+        ///
+        /// Possibilities include:
+        ///
+        /// *  There is out-of-band data on a TCP socket (see
+        ///    [tcp(7)](https://man7.org/linux/man-pages/man7/tcp.7.html)).
+        /// *  A pseudoterminal master in packet mode has seen a state
+        ///    change on the slave (see
+        ///    [ioctl_tty(2)](https://man7.org/linux/man-pages/man2/ioctl_tty.2.html)).
+        /// *  A cgroup.events file has been modified (see
+        ///    [cgroups(7)](https://man7.org/linux/man-pages/man7/cgroups.7.html)).
+        POLLPRI;
+        /// Writing is now possible, though a write larger that the
+        /// available space in a socket or pipe will still block (unless
+        /// `O_NONBLOCK` is set).
+        POLLOUT;
+        /// Equivalent to [`POLLIN`](constant.POLLIN.html)
+        #[cfg(not(target_os = "redox"))]
+        #[cfg_attr(docsrs, doc(cfg(all())))]
+        POLLRDNORM;
+        #[cfg(not(target_os = "redox"))]
+        #[cfg_attr(docsrs, doc(cfg(all())))]
+        /// Equivalent to [`POLLOUT`](constant.POLLOUT.html)
+        POLLWRNORM;
+        /// Priority band data can be read (generally unused on Linux).
+        #[cfg(not(target_os = "redox"))]
+        #[cfg_attr(docsrs, doc(cfg(all())))]
+        POLLRDBAND;
+        /// Priority data may be written.
+        #[cfg(not(target_os = "redox"))]
+        #[cfg_attr(docsrs, doc(cfg(all())))]
+        POLLWRBAND;
+        /// Error condition (only returned in
+        /// [`PollFd::revents`](struct.PollFd.html#method.revents);
+        /// ignored in [`PollFd::new`](struct.PollFd.html#method.new)).
+        /// This bit is also set for a file descriptor referring to the
+        /// write end of a pipe when the read end has been closed.
+        POLLERR;
+        /// Hang up (only returned in [`PollFd::revents`](struct.PollFd.html#method.revents);
+        /// ignored in [`PollFd::new`](struct.PollFd.html#method.new)).
+        /// Note that when reading from a channel such as a pipe or a stream
+        /// socket, this event merely indicates that the peer closed its
+        /// end of the channel.  Subsequent reads from the channel will
+        /// return 0 (end of file) only after all outstanding data in the
+        /// channel has been consumed.
+        POLLHUP;
+        /// Invalid request: `fd` not open (only returned in
+        /// [`PollFd::revents`](struct.PollFd.html#method.revents);
+        /// ignored in [`PollFd::new`](struct.PollFd.html#method.new)).
+        POLLNVAL;
+    }
+}
+
+/// `poll` waits for one of a set of file descriptors to become ready to perform I/O.
+/// ([`poll(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/poll.html))
+///
+/// `fds` contains all [`PollFd`](struct.PollFd.html) to poll.
+/// The function will return as soon as any event occur for any of these `PollFd`s.
+///
+/// The `timeout` argument specifies the number of milliseconds that `poll()`
+/// should block waiting for a file descriptor to become ready.  The call
+/// will block until either:
+///
+/// *  a file descriptor becomes ready;
+/// *  the call is interrupted by a signal handler; or
+/// *  the timeout expires.
+///
+/// Note that the timeout interval will be rounded up to the system clock
+/// granularity, and kernel scheduling delays mean that the blocking
+/// interval may overrun by a small amount.  Specifying a negative value
+/// in timeout means an infinite timeout.  Specifying a timeout of zero
+/// causes `poll()` to return immediately, even if no file descriptors are
+/// ready.
+pub fn poll(fds: &mut [PollFd], timeout: libc::c_int) -> Result<libc::c_int> {
+    let res = unsafe {
+        libc::poll(
+            fds.as_mut_ptr() as *mut libc::pollfd,
+            fds.len() as libc::nfds_t,
+            timeout,
+        )
+    };
+
+    Errno::result(res)
+}
+
+feature! {
+#![feature = "signal"]
+/// `ppoll()` allows an application to safely wait until either a file
+/// descriptor becomes ready or until a signal is caught.
+/// ([`poll(2)`](https://man7.org/linux/man-pages/man2/poll.2.html))
+///
+/// `ppoll` behaves like `poll`, but let you specify what signals may interrupt it
+/// with the `sigmask` argument. If you want `ppoll` to block indefinitely,
+/// specify `None` as `timeout` (it is like `timeout = -1` for `poll`).
+/// If `sigmask` is `None`, then no signal mask manipulation is performed,
+/// so in that case `ppoll` differs from `poll` only in the precision of the
+/// timeout argument.
+///
+#[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd", target_os = "linux"))]
+pub fn ppoll(
+    fds: &mut [PollFd],
+    timeout: Option<crate::sys::time::TimeSpec>,
+    sigmask: Option<crate::sys::signal::SigSet>
+    ) -> Result<libc::c_int>
+{
+    let timeout = timeout.as_ref().map_or(core::ptr::null(), |r| r.as_ref());
+    let sigmask = sigmask.as_ref().map_or(core::ptr::null(), |r| r.as_ref());
+    let res = unsafe {
+        libc::ppoll(fds.as_mut_ptr() as *mut libc::pollfd,
+                    fds.len() as libc::nfds_t,
+                    timeout,
+                    sigmask)
+    };
+    Errno::result(res)
+}
+}