Adding upstream version 115.7.0esr.upstream/115.7.0esr

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

1 files changed, 1241 insertions, 0 deletions

diff --git a/third_party/rust/nix/src/sys/aio.rs b/third_party/rust/nix/src/sys/aio.rs
new file mode 100644
index 0000000000..e2ce19b79d
--- /dev/null
+++ b/third_party/rust/nix/src/sys/aio.rs
@@ -0,0 +1,1241 @@
+// vim: tw=80
+//! POSIX Asynchronous I/O
+//!
+//! The POSIX AIO interface is used for asynchronous I/O on files and disk-like
+//! devices.  It supports [`read`](struct.AioRead.html#method.new),
+//! [`write`](struct.AioWrite.html#method.new),
+//! [`fsync`](struct.AioFsync.html#method.new),
+//! [`readv`](struct.AioReadv.html#method.new), and
+//! [`writev`](struct.AioWritev.html#method.new), operations, subject to
+//! platform support.  Completion
+//! notifications can optionally be delivered via
+//! [signals](../signal/enum.SigevNotify.html#variant.SigevSignal), via the
+//! [`aio_suspend`](fn.aio_suspend.html) function, or via polling.  Some
+//! platforms support other completion
+//! notifications, such as
+//! [kevent](../signal/enum.SigevNotify.html#variant.SigevKevent).
+//!
+//! Multiple operations may be submitted in a batch with
+//! [`lio_listio`](fn.lio_listio.html), though the standard does not guarantee
+//! that they will be executed atomically.
+//!
+//! Outstanding operations may be cancelled with
+//! [`cancel`](trait.Aio.html#method.cancel) or
+//! [`aio_cancel_all`](fn.aio_cancel_all.html), though the operating system may
+//! not support this for all filesystems and devices.
+#[cfg(target_os = "freebsd")]
+use std::io::{IoSlice, IoSliceMut};
+use std::{
+    convert::TryFrom,
+    fmt::{self, Debug},
+    marker::{PhantomData, PhantomPinned},
+    mem,
+    os::unix::io::RawFd,
+    pin::Pin,
+    ptr, thread,
+};
+
+use libc::{c_void, off_t};
+use pin_utils::unsafe_pinned;
+
+use crate::{
+    errno::Errno,
+    sys::{signal::*, time::TimeSpec},
+    Result,
+};
+
+libc_enum! {
+    /// Mode for `AioCb::fsync`.  Controls whether only data or both data and
+    /// metadata are synced.
+    #[repr(i32)]
+    #[non_exhaustive]
+    pub enum AioFsyncMode {
+        /// do it like `fsync`
+        O_SYNC,
+        /// on supported operating systems only, do it like `fdatasync`
+        #[cfg(any(target_os = "ios",
+                  target_os = "linux",
+                  target_os = "macos",
+                  target_os = "netbsd",
+                  target_os = "openbsd"))]
+        #[cfg_attr(docsrs, doc(cfg(all())))]
+        O_DSYNC
+    }
+    impl TryFrom<i32>
+}
+
+libc_enum! {
+    /// Mode for [`lio_listio`](fn.lio_listio.html)
+    #[repr(i32)]
+    pub enum LioMode {
+        /// Requests that [`lio_listio`](fn.lio_listio.html) block until all
+        /// requested operations have been completed
+        LIO_WAIT,
+        /// Requests that [`lio_listio`](fn.lio_listio.html) return immediately
+        LIO_NOWAIT,
+    }
+}
+
+/// Return values for [`AioCb::cancel`](struct.AioCb.html#method.cancel) and
+/// [`aio_cancel_all`](fn.aio_cancel_all.html)
+#[repr(i32)]
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+pub enum AioCancelStat {
+    /// All outstanding requests were canceled
+    AioCanceled = libc::AIO_CANCELED,
+    /// Some requests were not canceled.  Their status should be checked with
+    /// `AioCb::error`
+    AioNotCanceled = libc::AIO_NOTCANCELED,
+    /// All of the requests have already finished
+    AioAllDone = libc::AIO_ALLDONE,
+}
+
+/// Newtype that adds Send and Sync to libc::aiocb, which contains raw pointers
+#[repr(transparent)]
+struct LibcAiocb(libc::aiocb);
+
+unsafe impl Send for LibcAiocb {}
+unsafe impl Sync for LibcAiocb {}
+
+/// Base class for all AIO operations.  Should only be used directly when
+/// checking for completion.
+// We could create some kind of AsPinnedMut trait, and implement it for all aio
+// ops, allowing the crate's users to get pinned references to `AioCb`.  That
+// could save some code for things like polling methods.  But IMHO it would
+// provide polymorphism at the wrong level.  Instead, the best place for
+// polymorphism is at the level of `Futures`.
+#[repr(C)]
+struct AioCb {
+    aiocb: LibcAiocb,
+    /// Could this `AioCb` potentially have any in-kernel state?
+    // It would be really nice to perform the in-progress check entirely at
+    // compile time.  But I can't figure out how, because:
+    // * Future::poll takes a `Pin<&mut self>` rather than `self`, and
+    // * Rust's lack of an equivalent of C++'s Guaranteed Copy Elision means
+    //   that there's no way to write an AioCb constructor that neither boxes
+    //   the object itself, nor moves it during return.
+    in_progress: bool,
+}
+
+impl AioCb {
+    pin_utils::unsafe_unpinned!(aiocb: LibcAiocb);
+
+    fn aio_return(mut self: Pin<&mut Self>) -> Result<usize> {
+        self.in_progress = false;
+        unsafe {
+            let p: *mut libc::aiocb = &mut self.aiocb.0;
+            Errno::result(libc::aio_return(p))
+        }
+        .map(|r| r as usize)
+    }
+
+    fn cancel(mut self: Pin<&mut Self>) -> Result<AioCancelStat> {
+        let r = unsafe {
+            libc::aio_cancel(self.aiocb.0.aio_fildes, &mut self.aiocb.0)
+        };
+        match r {
+            libc::AIO_CANCELED => Ok(AioCancelStat::AioCanceled),
+            libc::AIO_NOTCANCELED => Ok(AioCancelStat::AioNotCanceled),
+            libc::AIO_ALLDONE => Ok(AioCancelStat::AioAllDone),
+            -1 => Err(Errno::last()),
+            _ => panic!("unknown aio_cancel return value"),
+        }
+    }
+
+    fn common_init(fd: RawFd, prio: i32, sigev_notify: SigevNotify) -> Self {
+        // Use mem::zeroed instead of explicitly zeroing each field, because the
+        // number and name of reserved fields is OS-dependent.  On some OSes,
+        // some reserved fields are used the kernel for state, and must be
+        // explicitly zeroed when allocated.
+        let mut a = unsafe { mem::zeroed::<libc::aiocb>() };
+        a.aio_fildes = fd;
+        a.aio_reqprio = prio;
+        a.aio_sigevent = SigEvent::new(sigev_notify).sigevent();
+        AioCb {
+            aiocb: LibcAiocb(a),
+            in_progress: false,
+        }
+    }
+
+    fn error(self: Pin<&mut Self>) -> Result<()> {
+        let r = unsafe { libc::aio_error(&self.aiocb().0) };
+        match r {
+            0 => Ok(()),
+            num if num > 0 => Err(Errno::from_i32(num)),
+            -1 => Err(Errno::last()),
+            num => panic!("unknown aio_error return value {:?}", num),
+        }
+    }
+
+    fn in_progress(&self) -> bool {
+        self.in_progress
+    }
+
+    fn set_in_progress(mut self: Pin<&mut Self>) {
+        self.as_mut().in_progress = true;
+    }
+
+    /// Update the notification settings for an existing AIO operation that has
+    /// not yet been submitted.
+    // Takes a normal reference rather than a pinned one because this method is
+    // normally called before the object needs to be pinned, that is, before
+    // it's been submitted to the kernel.
+    fn set_sigev_notify(&mut self, sigev_notify: SigevNotify) {
+        assert!(
+            !self.in_progress,
+            "Can't change notification settings for an in-progress operation"
+        );
+        self.aiocb.0.aio_sigevent = SigEvent::new(sigev_notify).sigevent();
+    }
+}
+
+impl Debug for AioCb {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("AioCb")
+            .field("aiocb", &self.aiocb.0)
+            .field("in_progress", &self.in_progress)
+            .finish()
+    }
+}
+
+impl Drop for AioCb {
+    /// If the `AioCb` has no remaining state in the kernel, just drop it.
+    /// Otherwise, dropping constitutes a resource leak, which is an error
+    fn drop(&mut self) {
+        assert!(
+            thread::panicking() || !self.in_progress,
+            "Dropped an in-progress AioCb"
+        );
+    }
+}
+
+/// Methods common to all AIO operations
+pub trait Aio {
+    /// The return type of [`Aio::aio_return`].
+    type Output;
+
+    /// Retrieve return status of an asynchronous operation.
+    ///
+    /// Should only be called once for each operation, after [`Aio::error`]
+    /// indicates that it has completed.  The result is the same as for the
+    /// synchronous `read(2)`, `write(2)`, of `fsync(2)` functions.
+    ///
+    /// # References
+    ///
+    /// [aio_return](https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_return.html)
+    fn aio_return(self: Pin<&mut Self>) -> Result<Self::Output>;
+
+    /// Cancels an outstanding AIO request.
+    ///
+    /// The operating system is not required to implement cancellation for all
+    /// file and device types.  Even if it does, there is no guarantee that the
+    /// operation has not already completed.  So the caller must check the
+    /// result and handle operations that were not canceled or that have already
+    /// completed.
+    ///
+    /// # Examples
+    ///
+    /// Cancel an outstanding aio operation.  Note that we must still call
+    /// `aio_return` to free resources, even though we don't care about the
+    /// result.
+    ///
+    /// ```
+    /// # use nix::errno::Errno;
+    /// # use nix::Error;
+    /// # use nix::sys::aio::*;
+    /// # use nix::sys::signal::SigevNotify;
+    /// # use std::{thread, time};
+    /// # use std::io::Write;
+    /// # use std::os::unix::io::AsRawFd;
+    /// # use tempfile::tempfile;
+    /// let wbuf = b"CDEF";
+    /// let mut f = tempfile().unwrap();
+    /// let mut aiocb = Box::pin(AioWrite::new(f.as_raw_fd(),
+    ///     2,   //offset
+    ///     &wbuf[..],
+    ///     0,   //priority
+    ///     SigevNotify::SigevNone));
+    /// aiocb.as_mut().submit().unwrap();
+    /// let cs = aiocb.as_mut().cancel().unwrap();
+    /// if cs == AioCancelStat::AioNotCanceled {
+    ///     while (aiocb.as_mut().error() == Err(Errno::EINPROGRESS)) {
+    ///         thread::sleep(time::Duration::from_millis(10));
+    ///     }
+    /// }
+    /// // Must call `aio_return`, but ignore the result
+    /// let _ = aiocb.as_mut().aio_return();
+    /// ```
+    ///
+    /// # References
+    ///
+    /// [aio_cancel](https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_cancel.html)
+    fn cancel(self: Pin<&mut Self>) -> Result<AioCancelStat>;
+
+    /// Retrieve error status of an asynchronous operation.
+    ///
+    /// If the request has not yet completed, returns `EINPROGRESS`.  Otherwise,
+    /// returns `Ok` or any other error.
+    ///
+    /// # Examples
+    ///
+    /// Issue an aio operation and use `error` to poll for completion.  Polling
+    /// is an alternative to `aio_suspend`, used by most of the other examples.
+    ///
+    /// ```
+    /// # use nix::errno::Errno;
+    /// # use nix::Error;
+    /// # use nix::sys::aio::*;
+    /// # use nix::sys::signal::SigevNotify;
+    /// # use std::{thread, time};
+    /// # use std::os::unix::io::AsRawFd;
+    /// # use tempfile::tempfile;
+    /// const WBUF: &[u8] = b"abcdef123456";
+    /// let mut f = tempfile().unwrap();
+    /// let mut aiocb = Box::pin(AioWrite::new(f.as_raw_fd(),
+    ///     2,   //offset
+    ///     WBUF,
+    ///     0,   //priority
+    ///     SigevNotify::SigevNone));
+    /// aiocb.as_mut().submit().unwrap();
+    /// while (aiocb.as_mut().error() == Err(Errno::EINPROGRESS)) {
+    ///     thread::sleep(time::Duration::from_millis(10));
+    /// }
+    /// assert_eq!(aiocb.as_mut().aio_return().unwrap(), WBUF.len());
+    /// ```
+    ///
+    /// # References
+    ///
+    /// [aio_error](https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_error.html)
+    fn error(self: Pin<&mut Self>) -> Result<()>;
+
+    /// Returns the underlying file descriptor associated with the operation.
+    fn fd(&self) -> RawFd;
+
+    /// Does this operation currently have any in-kernel state?
+    ///
+    /// Dropping an operation that does have in-kernel state constitutes a
+    /// resource leak.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// # use nix::errno::Errno;
+    /// # use nix::Error;
+    /// # use nix::sys::aio::*;
+    /// # use nix::sys::signal::SigevNotify::SigevNone;
+    /// # use std::{thread, time};
+    /// # use std::os::unix::io::AsRawFd;
+    /// # use tempfile::tempfile;
+    /// let f = tempfile().unwrap();
+    /// let mut aiof = Box::pin(AioFsync::new(f.as_raw_fd(), AioFsyncMode::O_SYNC,
+    ///     0, SigevNone));
+    /// assert!(!aiof.as_mut().in_progress());
+    /// aiof.as_mut().submit().expect("aio_fsync failed early");
+    /// assert!(aiof.as_mut().in_progress());
+    /// while (aiof.as_mut().error() == Err(Errno::EINPROGRESS)) {
+    ///     thread::sleep(time::Duration::from_millis(10));
+    /// }
+    /// aiof.as_mut().aio_return().expect("aio_fsync failed late");
+    /// assert!(!aiof.as_mut().in_progress());
+    /// ```
+    fn in_progress(&self) -> bool;
+
+    /// Returns the priority of the `AioCb`
+    fn priority(&self) -> i32;
+
+    /// Update the notification settings for an existing AIO operation that has
+    /// not yet been submitted.
+    fn set_sigev_notify(&mut self, sev: SigevNotify);
+
+    /// Returns the `SigEvent` that will be used for notification.
+    fn sigevent(&self) -> SigEvent;
+
+    /// Actually start the I/O operation.
+    ///
+    /// After calling this method and until [`Aio::aio_return`] returns `Ok`,
+    /// the structure may not be moved in memory.
+    fn submit(self: Pin<&mut Self>) -> Result<()>;
+}
+
+macro_rules! aio_methods {
+    () => {
+        fn cancel(self: Pin<&mut Self>) -> Result<AioCancelStat> {
+            self.aiocb().cancel()
+        }
+
+        fn error(self: Pin<&mut Self>) -> Result<()> {
+            self.aiocb().error()
+        }
+
+        fn fd(&self) -> RawFd {
+            self.aiocb.aiocb.0.aio_fildes
+        }
+
+        fn in_progress(&self) -> bool {
+            self.aiocb.in_progress()
+        }
+
+        fn priority(&self) -> i32 {
+            self.aiocb.aiocb.0.aio_reqprio
+        }
+
+        fn set_sigev_notify(&mut self, sev: SigevNotify) {
+            self.aiocb.set_sigev_notify(sev)
+        }
+
+        fn sigevent(&self) -> SigEvent {
+            SigEvent::from(&self.aiocb.aiocb.0.aio_sigevent)
+        }
+    };
+    ($func:ident) => {
+        aio_methods!();
+
+        fn aio_return(self: Pin<&mut Self>) -> Result<<Self as Aio>::Output> {
+            self.aiocb().aio_return()
+        }
+
+        fn submit(mut self: Pin<&mut Self>) -> Result<()> {
+            let p: *mut libc::aiocb = &mut self.as_mut().aiocb().aiocb.0;
+            Errno::result({ unsafe { libc::$func(p) } }).map(|_| {
+                self.aiocb().set_in_progress();
+            })
+        }
+    };
+}
+
+/// An asynchronous version of `fsync(2)`.
+///
+/// # References
+///
+/// [aio_fsync](https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_fsync.html)
+/// # Examples
+///
+/// ```
+/// # use nix::errno::Errno;
+/// # use nix::Error;
+/// # use nix::sys::aio::*;
+/// # use nix::sys::signal::SigevNotify::SigevNone;
+/// # use std::{thread, time};
+/// # use std::os::unix::io::AsRawFd;
+/// # use tempfile::tempfile;
+/// let f = tempfile().unwrap();
+/// let mut aiof = Box::pin(AioFsync::new(f.as_raw_fd(), AioFsyncMode::O_SYNC,
+///     0, SigevNone));
+/// aiof.as_mut().submit().expect("aio_fsync failed early");
+/// while (aiof.as_mut().error() == Err(Errno::EINPROGRESS)) {
+///     thread::sleep(time::Duration::from_millis(10));
+/// }
+/// aiof.as_mut().aio_return().expect("aio_fsync failed late");
+/// ```
+#[derive(Debug)]
+#[repr(transparent)]
+pub struct AioFsync {
+    aiocb: AioCb,
+    _pin: PhantomPinned,
+}
+
+impl AioFsync {
+    unsafe_pinned!(aiocb: AioCb);
+
+    /// Returns the operation's fsync mode: data and metadata or data only?
+    pub fn mode(&self) -> AioFsyncMode {
+        AioFsyncMode::try_from(self.aiocb.aiocb.0.aio_lio_opcode).unwrap()
+    }
+
+    /// Create a new `AioFsync`.
+    ///
+    /// # Arguments
+    ///
+    /// * `fd`:           File descriptor to sync.
+    /// * `mode`:         Whether to sync file metadata too, or just data.
+    /// * `prio`:         If POSIX Prioritized IO is supported, then the
+    ///                   operation will be prioritized at the process's
+    ///                   priority level minus `prio`.
+    /// * `sigev_notify`: Determines how you will be notified of event
+    ///                   completion.
+    pub fn new(
+        fd: RawFd,
+        mode: AioFsyncMode,
+        prio: i32,
+        sigev_notify: SigevNotify,
+    ) -> Self {
+        let mut aiocb = AioCb::common_init(fd, prio, sigev_notify);
+        // To save some memory, store mode in an unused field of the AioCb.
+        // True it isn't very much memory, but downstream creates will likely
+        // create an enum containing this and other AioCb variants and pack
+        // those enums into data structures like Vec, so it adds up.
+        aiocb.aiocb.0.aio_lio_opcode = mode as libc::c_int;
+        AioFsync {
+            aiocb,
+            _pin: PhantomPinned,
+        }
+    }
+}
+
+impl Aio for AioFsync {
+    type Output = ();
+
+    aio_methods!();
+
+    fn aio_return(self: Pin<&mut Self>) -> Result<()> {
+        self.aiocb().aio_return().map(drop)
+    }
+
+    fn submit(mut self: Pin<&mut Self>) -> Result<()> {
+        let aiocb = &mut self.as_mut().aiocb().aiocb.0;
+        let mode = mem::replace(&mut aiocb.aio_lio_opcode, 0);
+        let p: *mut libc::aiocb = aiocb;
+        Errno::result(unsafe { libc::aio_fsync(mode, p) }).map(|_| {
+            self.aiocb().set_in_progress();
+        })
+    }
+}
+
+// AioFsync does not need AsMut, since it can't be used with lio_listio
+
+impl AsRef<libc::aiocb> for AioFsync {
+    fn as_ref(&self) -> &libc::aiocb {
+        &self.aiocb.aiocb.0
+    }
+}
+
+/// Asynchronously reads from a file descriptor into a buffer
+///
+/// # References
+///
+/// [aio_read](https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_read.html)
+///
+/// # Examples
+///
+///
+/// ```
+/// # use nix::errno::Errno;
+/// # use nix::Error;
+/// # use nix::sys::aio::*;
+/// # use nix::sys::signal::SigevNotify;
+/// # use std::{thread, time};
+/// # use std::io::Write;
+/// # use std::os::unix::io::AsRawFd;
+/// # use tempfile::tempfile;
+/// const INITIAL: &[u8] = b"abcdef123456";
+/// const LEN: usize = 4;
+/// let mut rbuf = vec![0; LEN];
+/// let mut f = tempfile().unwrap();
+/// f.write_all(INITIAL).unwrap();
+/// {
+///     let mut aior = Box::pin(
+///         AioRead::new(
+///             f.as_raw_fd(),
+///             2,   //offset
+///             &mut rbuf,
+///             0,   //priority
+///             SigevNotify::SigevNone
+///         )
+///     );
+///     aior.as_mut().submit().unwrap();
+///     while (aior.as_mut().error() == Err(Errno::EINPROGRESS)) {
+///         thread::sleep(time::Duration::from_millis(10));
+///     }
+///     assert_eq!(aior.as_mut().aio_return().unwrap(), LEN);
+/// }
+/// assert_eq!(rbuf, b"cdef");
+/// ```
+#[derive(Debug)]
+#[repr(transparent)]
+pub struct AioRead<'a> {
+    aiocb: AioCb,
+    _data: PhantomData<&'a [u8]>,
+    _pin: PhantomPinned,
+}
+
+impl<'a> AioRead<'a> {
+    unsafe_pinned!(aiocb: AioCb);
+
+    /// Returns the requested length of the aio operation in bytes
+    ///
+    /// This method returns the *requested* length of the operation.  To get the
+    /// number of bytes actually read or written by a completed operation, use
+    /// `aio_return` instead.
+    pub fn nbytes(&self) -> usize {
+        self.aiocb.aiocb.0.aio_nbytes
+    }
+
+    /// Create a new `AioRead`, placing the data in a mutable slice.
+    ///
+    /// # Arguments
+    ///
+    /// * `fd`:           File descriptor to read from
+    /// * `offs`:         File offset
+    /// * `buf`:          A memory buffer.  It must outlive the `AioRead`.
+    /// * `prio`:         If POSIX Prioritized IO is supported, then the
+    ///                   operation will be prioritized at the process's
+    ///                   priority level minus `prio`
+    /// * `sigev_notify`: Determines how you will be notified of event
+    ///                   completion.
+    pub fn new(
+        fd: RawFd,
+        offs: off_t,
+        buf: &'a mut [u8],
+        prio: i32,
+        sigev_notify: SigevNotify,
+    ) -> Self {
+        let mut aiocb = AioCb::common_init(fd, prio, sigev_notify);
+        aiocb.aiocb.0.aio_nbytes = buf.len();
+        aiocb.aiocb.0.aio_buf = buf.as_mut_ptr() as *mut c_void;
+        aiocb.aiocb.0.aio_lio_opcode = libc::LIO_READ;
+        aiocb.aiocb.0.aio_offset = offs;
+        AioRead {
+            aiocb,
+            _data: PhantomData,
+            _pin: PhantomPinned,
+        }
+    }
+
+    /// Returns the file offset of the operation.
+    pub fn offset(&self) -> off_t {
+        self.aiocb.aiocb.0.aio_offset
+    }
+}
+
+impl<'a> Aio for AioRead<'a> {
+    type Output = usize;
+
+    aio_methods!(aio_read);
+}
+
+impl<'a> AsMut<libc::aiocb> for AioRead<'a> {
+    fn as_mut(&mut self) -> &mut libc::aiocb {
+        &mut self.aiocb.aiocb.0
+    }
+}
+
+impl<'a> AsRef<libc::aiocb> for AioRead<'a> {
+    fn as_ref(&self) -> &libc::aiocb {
+        &self.aiocb.aiocb.0
+    }
+}
+
+/// Asynchronously reads from a file descriptor into a scatter/gather list of buffers.
+///
+/// # References
+///
+/// [aio_readv](https://www.freebsd.org/cgi/man.cgi?query=aio_readv)
+///
+/// # Examples
+///
+///
+#[cfg_attr(fbsd14, doc = " ```")]
+#[cfg_attr(not(fbsd14), doc = " ```no_run")]
+/// # use nix::errno::Errno;
+/// # use nix::Error;
+/// # use nix::sys::aio::*;
+/// # use nix::sys::signal::SigevNotify;
+/// # use std::{thread, time};
+/// # use std::io::{IoSliceMut, Write};
+/// # use std::os::unix::io::AsRawFd;
+/// # use tempfile::tempfile;
+/// const INITIAL: &[u8] = b"abcdef123456";
+/// let mut rbuf0 = vec![0; 4];
+/// let mut rbuf1 = vec![0; 2];
+/// let expected_len = rbuf0.len() + rbuf1.len();
+/// let mut rbufs = [IoSliceMut::new(&mut rbuf0), IoSliceMut::new(&mut rbuf1)];
+/// let mut f = tempfile().unwrap();
+/// f.write_all(INITIAL).unwrap();
+/// {
+///     let mut aior = Box::pin(
+///         AioReadv::new(
+///             f.as_raw_fd(),
+///             2,   //offset
+///             &mut rbufs,
+///             0,   //priority
+///             SigevNotify::SigevNone
+///         )
+///     );
+///     aior.as_mut().submit().unwrap();
+///     while (aior.as_mut().error() == Err(Errno::EINPROGRESS)) {
+///         thread::sleep(time::Duration::from_millis(10));
+///     }
+///     assert_eq!(aior.as_mut().aio_return().unwrap(), expected_len);
+/// }
+/// assert_eq!(rbuf0, b"cdef");
+/// assert_eq!(rbuf1, b"12");
+/// ```
+#[cfg(target_os = "freebsd")]
+#[derive(Debug)]
+#[repr(transparent)]
+pub struct AioReadv<'a> {
+    aiocb: AioCb,
+    _data: PhantomData<&'a [&'a [u8]]>,
+    _pin: PhantomPinned,
+}
+
+#[cfg(target_os = "freebsd")]
+impl<'a> AioReadv<'a> {
+    unsafe_pinned!(aiocb: AioCb);
+
+    /// Returns the number of buffers the operation will read into.
+    pub fn iovlen(&self) -> usize {
+        self.aiocb.aiocb.0.aio_nbytes
+    }
+
+    /// Create a new `AioReadv`, placing the data in a list of mutable slices.
+    ///
+    /// # Arguments
+    ///
+    /// * `fd`:           File descriptor to read from
+    /// * `offs`:         File offset
+    /// * `bufs`:         A scatter/gather list of memory buffers.  They must
+    ///                   outlive the `AioReadv`.
+    /// * `prio`:         If POSIX Prioritized IO is supported, then the
+    ///                   operation will be prioritized at the process's
+    ///                   priority level minus `prio`
+    /// * `sigev_notify`: Determines how you will be notified of event
+    ///                   completion.
+    pub fn new(
+        fd: RawFd,
+        offs: off_t,
+        bufs: &mut [IoSliceMut<'a>],
+        prio: i32,
+        sigev_notify: SigevNotify,
+    ) -> Self {
+        let mut aiocb = AioCb::common_init(fd, prio, sigev_notify);
+        // In vectored mode, aio_nbytes stores the length of the iovec array,
+        // not the byte count.
+        aiocb.aiocb.0.aio_nbytes = bufs.len();
+        aiocb.aiocb.0.aio_buf = bufs.as_mut_ptr() as *mut c_void;
+        aiocb.aiocb.0.aio_lio_opcode = libc::LIO_READV;
+        aiocb.aiocb.0.aio_offset = offs;
+        AioReadv {
+            aiocb,
+            _data: PhantomData,
+            _pin: PhantomPinned,
+        }
+    }
+
+    /// Returns the file offset of the operation.
+    pub fn offset(&self) -> off_t {
+        self.aiocb.aiocb.0.aio_offset
+    }
+}
+
+#[cfg(target_os = "freebsd")]
+impl<'a> Aio for AioReadv<'a> {
+    type Output = usize;
+
+    aio_methods!(aio_readv);
+}
+
+#[cfg(target_os = "freebsd")]
+impl<'a> AsMut<libc::aiocb> for AioReadv<'a> {
+    fn as_mut(&mut self) -> &mut libc::aiocb {
+        &mut self.aiocb.aiocb.0
+    }
+}
+
+#[cfg(target_os = "freebsd")]
+impl<'a> AsRef<libc::aiocb> for AioReadv<'a> {
+    fn as_ref(&self) -> &libc::aiocb {
+        &self.aiocb.aiocb.0
+    }
+}
+
+/// Asynchronously writes from a buffer to a file descriptor
+///
+/// # References
+///
+/// [aio_write](https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_write.html)
+///
+/// # Examples
+///
+/// ```
+/// # use nix::errno::Errno;
+/// # use nix::Error;
+/// # use nix::sys::aio::*;
+/// # use nix::sys::signal::SigevNotify;
+/// # use std::{thread, time};
+/// # use std::os::unix::io::AsRawFd;
+/// # use tempfile::tempfile;
+/// const WBUF: &[u8] = b"abcdef123456";
+/// let mut f = tempfile().unwrap();
+/// let mut aiow = Box::pin(
+///     AioWrite::new(
+///         f.as_raw_fd(),
+///         2,   //offset
+///         WBUF,
+///         0,   //priority
+///         SigevNotify::SigevNone
+///     )
+/// );
+/// aiow.as_mut().submit().unwrap();
+/// while (aiow.as_mut().error() == Err(Errno::EINPROGRESS)) {
+///     thread::sleep(time::Duration::from_millis(10));
+/// }
+/// assert_eq!(aiow.as_mut().aio_return().unwrap(), WBUF.len());
+/// ```
+#[derive(Debug)]
+#[repr(transparent)]
+pub struct AioWrite<'a> {
+    aiocb: AioCb,
+    _data: PhantomData<&'a [u8]>,
+    _pin: PhantomPinned,
+}
+
+impl<'a> AioWrite<'a> {
+    unsafe_pinned!(aiocb: AioCb);
+
+    /// Returns the requested length of the aio operation in bytes
+    ///
+    /// This method returns the *requested* length of the operation.  To get the
+    /// number of bytes actually read or written by a completed operation, use
+    /// `aio_return` instead.
+    pub fn nbytes(&self) -> usize {
+        self.aiocb.aiocb.0.aio_nbytes
+    }
+
+    /// Construct a new `AioWrite`.
+    ///
+    /// # Arguments
+    ///
+    /// * `fd`:           File descriptor to write to
+    /// * `offs`:         File offset
+    /// * `buf`:          A memory buffer.  It must outlive the `AioWrite`.
+    /// * `prio`:         If POSIX Prioritized IO is supported, then the
+    ///                   operation will be prioritized at the process's
+    ///                   priority level minus `prio`
+    /// * `sigev_notify`: Determines how you will be notified of event
+    ///                   completion.
+    pub fn new(
+        fd: RawFd,
+        offs: off_t,
+        buf: &'a [u8],
+        prio: i32,
+        sigev_notify: SigevNotify,
+    ) -> Self {
+        let mut aiocb = AioCb::common_init(fd, prio, sigev_notify);
+        aiocb.aiocb.0.aio_nbytes = buf.len();
+        // casting an immutable buffer to a mutable pointer looks unsafe,
+        // but technically its only unsafe to dereference it, not to create
+        // it.  Type Safety guarantees that we'll never pass aiocb to
+        // aio_read or aio_readv.
+        aiocb.aiocb.0.aio_buf = buf.as_ptr() as *mut c_void;
+        aiocb.aiocb.0.aio_lio_opcode = libc::LIO_WRITE;
+        aiocb.aiocb.0.aio_offset = offs;
+        AioWrite {
+            aiocb,
+            _data: PhantomData,
+            _pin: PhantomPinned,
+        }
+    }
+
+    /// Returns the file offset of the operation.
+    pub fn offset(&self) -> off_t {
+        self.aiocb.aiocb.0.aio_offset
+    }
+}
+
+impl<'a> Aio for AioWrite<'a> {
+    type Output = usize;
+
+    aio_methods!(aio_write);
+}
+
+impl<'a> AsMut<libc::aiocb> for AioWrite<'a> {
+    fn as_mut(&mut self) -> &mut libc::aiocb {
+        &mut self.aiocb.aiocb.0
+    }
+}
+
+impl<'a> AsRef<libc::aiocb> for AioWrite<'a> {
+    fn as_ref(&self) -> &libc::aiocb {
+        &self.aiocb.aiocb.0
+    }
+}
+
+/// Asynchronously writes from a scatter/gather list of buffers to a file descriptor.
+///
+/// # References
+///
+/// [aio_writev](https://www.freebsd.org/cgi/man.cgi?query=aio_writev)
+///
+/// # Examples
+///
+#[cfg_attr(fbsd14, doc = " ```")]
+#[cfg_attr(not(fbsd14), doc = " ```no_run")]
+/// # use nix::errno::Errno;
+/// # use nix::Error;
+/// # use nix::sys::aio::*;
+/// # use nix::sys::signal::SigevNotify;
+/// # use std::{thread, time};
+/// # use std::io::IoSlice;
+/// # use std::os::unix::io::AsRawFd;
+/// # use tempfile::tempfile;
+/// const wbuf0: &[u8] = b"abcdef";
+/// const wbuf1: &[u8] = b"123456";
+/// let len = wbuf0.len() + wbuf1.len();
+/// let wbufs = [IoSlice::new(wbuf0), IoSlice::new(wbuf1)];
+/// let mut f = tempfile().unwrap();
+/// let mut aiow = Box::pin(
+///     AioWritev::new(
+///         f.as_raw_fd(),
+///         2,   //offset
+///         &wbufs,
+///         0,   //priority
+///         SigevNotify::SigevNone
+///     )
+/// );
+/// aiow.as_mut().submit().unwrap();
+/// while (aiow.as_mut().error() == Err(Errno::EINPROGRESS)) {
+///     thread::sleep(time::Duration::from_millis(10));
+/// }
+/// assert_eq!(aiow.as_mut().aio_return().unwrap(), len);
+/// ```
+#[cfg(target_os = "freebsd")]
+#[derive(Debug)]
+#[repr(transparent)]
+pub struct AioWritev<'a> {
+    aiocb: AioCb,
+    _data: PhantomData<&'a [&'a [u8]]>,
+    _pin: PhantomPinned,
+}
+
+#[cfg(target_os = "freebsd")]
+impl<'a> AioWritev<'a> {
+    unsafe_pinned!(aiocb: AioCb);
+
+    /// Returns the number of buffers the operation will read into.
+    pub fn iovlen(&self) -> usize {
+        self.aiocb.aiocb.0.aio_nbytes
+    }
+
+    /// Construct a new `AioWritev`.
+    ///
+    /// # Arguments
+    ///
+    /// * `fd`:           File descriptor to write to
+    /// * `offs`:         File offset
+    /// * `bufs`:         A scatter/gather list of memory buffers.  They must
+    ///                   outlive the `AioWritev`.
+    /// * `prio`:         If POSIX Prioritized IO is supported, then the
+    ///                   operation will be prioritized at the process's
+    ///                   priority level minus `prio`
+    /// * `sigev_notify`: Determines how you will be notified of event
+    ///                   completion.
+    pub fn new(
+        fd: RawFd,
+        offs: off_t,
+        bufs: &[IoSlice<'a>],
+        prio: i32,
+        sigev_notify: SigevNotify,
+    ) -> Self {
+        let mut aiocb = AioCb::common_init(fd, prio, sigev_notify);
+        // In vectored mode, aio_nbytes stores the length of the iovec array,
+        // not the byte count.
+        aiocb.aiocb.0.aio_nbytes = bufs.len();
+        // casting an immutable buffer to a mutable pointer looks unsafe,
+        // but technically its only unsafe to dereference it, not to create
+        // it.  Type Safety guarantees that we'll never pass aiocb to
+        // aio_read or aio_readv.
+        aiocb.aiocb.0.aio_buf = bufs.as_ptr() as *mut c_void;
+        aiocb.aiocb.0.aio_lio_opcode = libc::LIO_WRITEV;
+        aiocb.aiocb.0.aio_offset = offs;
+        AioWritev {
+            aiocb,
+            _data: PhantomData,
+            _pin: PhantomPinned,
+        }
+    }
+
+    /// Returns the file offset of the operation.
+    pub fn offset(&self) -> off_t {
+        self.aiocb.aiocb.0.aio_offset
+    }
+}
+
+#[cfg(target_os = "freebsd")]
+impl<'a> Aio for AioWritev<'a> {
+    type Output = usize;
+
+    aio_methods!(aio_writev);
+}
+
+#[cfg(target_os = "freebsd")]
+impl<'a> AsMut<libc::aiocb> for AioWritev<'a> {
+    fn as_mut(&mut self) -> &mut libc::aiocb {
+        &mut self.aiocb.aiocb.0
+    }
+}
+
+#[cfg(target_os = "freebsd")]
+impl<'a> AsRef<libc::aiocb> for AioWritev<'a> {
+    fn as_ref(&self) -> &libc::aiocb {
+        &self.aiocb.aiocb.0
+    }
+}
+
+/// Cancels outstanding AIO requests for a given file descriptor.
+///
+/// # Examples
+///
+/// Issue an aio operation, then cancel all outstanding operations on that file
+/// descriptor.
+///
+/// ```
+/// # use nix::errno::Errno;
+/// # use nix::Error;
+/// # use nix::sys::aio::*;
+/// # use nix::sys::signal::SigevNotify;
+/// # use std::{thread, time};
+/// # use std::io::Write;
+/// # use std::os::unix::io::AsRawFd;
+/// # use tempfile::tempfile;
+/// let wbuf = b"CDEF";
+/// let mut f = tempfile().unwrap();
+/// let mut aiocb = Box::pin(AioWrite::new(f.as_raw_fd(),
+///     2,   //offset
+///     &wbuf[..],
+///     0,   //priority
+///     SigevNotify::SigevNone));
+/// aiocb.as_mut().submit().unwrap();
+/// let cs = aio_cancel_all(f.as_raw_fd()).unwrap();
+/// if cs == AioCancelStat::AioNotCanceled {
+///     while (aiocb.as_mut().error() == Err(Errno::EINPROGRESS)) {
+///         thread::sleep(time::Duration::from_millis(10));
+///     }
+/// }
+/// // Must call `aio_return`, but ignore the result
+/// let _ = aiocb.as_mut().aio_return();
+/// ```
+///
+/// # References
+///
+/// [`aio_cancel`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_cancel.html)
+pub fn aio_cancel_all(fd: RawFd) -> Result<AioCancelStat> {
+    match unsafe { libc::aio_cancel(fd, ptr::null_mut()) } {
+        libc::AIO_CANCELED => Ok(AioCancelStat::AioCanceled),
+        libc::AIO_NOTCANCELED => Ok(AioCancelStat::AioNotCanceled),
+        libc::AIO_ALLDONE => Ok(AioCancelStat::AioAllDone),
+        -1 => Err(Errno::last()),
+        _ => panic!("unknown aio_cancel return value"),
+    }
+}
+
+/// Suspends the calling process until at least one of the specified operations
+/// have completed, a signal is delivered, or the timeout has passed.
+///
+/// If `timeout` is `None`, `aio_suspend` will block indefinitely.
+///
+/// # Examples
+///
+/// Use `aio_suspend` to block until an aio operation completes.
+///
+/// ```
+/// # use nix::sys::aio::*;
+/// # use nix::sys::signal::SigevNotify;
+/// # use std::os::unix::io::AsRawFd;
+/// # use tempfile::tempfile;
+/// const WBUF: &[u8] = b"abcdef123456";
+/// let mut f = tempfile().unwrap();
+/// let mut aiocb = Box::pin(AioWrite::new(f.as_raw_fd(),
+///     2,   //offset
+///     WBUF,
+///     0,   //priority
+///     SigevNotify::SigevNone));
+/// aiocb.as_mut().submit().unwrap();
+/// aio_suspend(&[&*aiocb], None).expect("aio_suspend failed");
+/// assert_eq!(aiocb.as_mut().aio_return().unwrap() as usize, WBUF.len());
+/// ```
+/// # References
+///
+/// [`aio_suspend`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_suspend.html)
+pub fn aio_suspend(
+    list: &[&dyn AsRef<libc::aiocb>],
+    timeout: Option<TimeSpec>,
+) -> Result<()> {
+    let p = list as *const [&dyn AsRef<libc::aiocb>]
+        as *const [*const libc::aiocb] as *const *const libc::aiocb;
+    let timep = match timeout {
+        None => ptr::null::<libc::timespec>(),
+        Some(x) => x.as_ref() as *const libc::timespec,
+    };
+    Errno::result(unsafe { libc::aio_suspend(p, list.len() as i32, timep) })
+        .map(drop)
+}
+
+/// Submits multiple asynchronous I/O requests with a single system call.
+///
+/// They are not guaranteed to complete atomically, and the order in which the
+/// requests are carried out is not specified. Reads, and writes may be freely
+/// mixed.
+///
+/// # Examples
+///
+/// Use `lio_listio` to submit an aio operation and wait for its completion. In
+/// this case, there is no need to use aio_suspend to wait or `error` to poll.
+/// This mode is useful for otherwise-synchronous programs that want to execute
+/// a handful of I/O operations in parallel.
+/// ```
+/// # use std::os::unix::io::AsRawFd;
+/// # use nix::sys::aio::*;
+/// # use nix::sys::signal::SigevNotify;
+/// # use tempfile::tempfile;
+/// const WBUF: &[u8] = b"abcdef123456";
+/// let mut f = tempfile().unwrap();
+/// let mut aiow = Box::pin(AioWrite::new(
+///     f.as_raw_fd(),
+///     2,      // offset
+///     WBUF,
+///     0,      // priority
+///     SigevNotify::SigevNone
+/// ));
+/// lio_listio(LioMode::LIO_WAIT, &mut[aiow.as_mut()], SigevNotify::SigevNone)
+///     .unwrap();
+/// // At this point, we are guaranteed that aiow is complete.
+/// assert_eq!(aiow.as_mut().aio_return().unwrap(), WBUF.len());
+/// ```
+///
+/// Use `lio_listio` to submit multiple asynchronous operations with a single
+/// syscall, but receive notification individually.  This is an efficient
+/// technique for reducing overall context-switch overhead, especially when
+/// combined with kqueue.
+/// ```
+/// # use std::os::unix::io::AsRawFd;
+/// # use std::thread;
+/// # use std::time;
+/// # use nix::errno::Errno;
+/// # use nix::sys::aio::*;
+/// # use nix::sys::signal::SigevNotify;
+/// # use tempfile::tempfile;
+/// const WBUF: &[u8] = b"abcdef123456";
+/// let mut f = tempfile().unwrap();
+/// let mut aiow = Box::pin(AioWrite::new(
+///     f.as_raw_fd(),
+///     2,      // offset
+///     WBUF,
+///     0,      // priority
+///     SigevNotify::SigevNone
+/// ));
+/// lio_listio(LioMode::LIO_NOWAIT, &mut[aiow.as_mut()], SigevNotify::SigevNone)
+///     .unwrap();
+/// // We must wait for the completion of each individual operation
+/// while (aiow.as_mut().error() == Err(Errno::EINPROGRESS)) {
+///     thread::sleep(time::Duration::from_millis(10));
+/// }
+/// assert_eq!(aiow.as_mut().aio_return().unwrap(), WBUF.len());
+/// ```
+///
+/// Use `lio_listio` to submit multiple operations, and receive notification
+/// only when all of them are complete.  This can be useful when there is some
+/// logical relationship between the operations.  But beware!  Errors or system
+/// resource limitations may cause `lio_listio` to return `EIO`, `EAGAIN`, or
+/// `EINTR`, in which case some but not all operations may have been submitted.
+/// In that case, you must check the status of each individual operation, and
+/// possibly resubmit some.
+/// ```
+/// # use libc::c_int;
+/// # use std::os::unix::io::AsRawFd;
+/// # use std::sync::atomic::{AtomicBool, Ordering};
+/// # use std::thread;
+/// # use std::time;
+/// # use lazy_static::lazy_static;
+/// # use nix::errno::Errno;
+/// # use nix::sys::aio::*;
+/// # use nix::sys::signal::*;
+/// # use tempfile::tempfile;
+/// lazy_static! {
+///     pub static ref SIGNALED: AtomicBool = AtomicBool::new(false);
+/// }
+///
+/// extern fn sigfunc(_: c_int) {
+///     SIGNALED.store(true, Ordering::Relaxed);
+/// }
+/// let sa = SigAction::new(SigHandler::Handler(sigfunc),
+///                         SaFlags::SA_RESETHAND,
+///                         SigSet::empty());
+/// SIGNALED.store(false, Ordering::Relaxed);
+/// unsafe { sigaction(Signal::SIGUSR2, &sa) }.unwrap();
+///
+/// const WBUF: &[u8] = b"abcdef123456";
+/// let mut f = tempfile().unwrap();
+/// let mut aiow = Box::pin(AioWrite::new(
+///     f.as_raw_fd(),
+///     2,      // offset
+///     WBUF,
+///     0,      // priority
+///     SigevNotify::SigevNone
+/// ));
+/// let sev = SigevNotify::SigevSignal { signal: Signal::SIGUSR2, si_value: 0 };
+/// lio_listio(LioMode::LIO_NOWAIT, &mut[aiow.as_mut()], sev).unwrap();
+/// while !SIGNALED.load(Ordering::Relaxed) {
+///     thread::sleep(time::Duration::from_millis(10));
+/// }
+/// // At this point, since `lio_listio` returned success and delivered its
+/// // notification, we know that all operations are complete.
+/// assert_eq!(aiow.as_mut().aio_return().unwrap(), WBUF.len());
+/// ```
+pub fn lio_listio(
+    mode: LioMode,
+    list: &mut [Pin<&mut dyn AsMut<libc::aiocb>>],
+    sigev_notify: SigevNotify,
+) -> Result<()> {
+    let p = list as *mut [Pin<&mut dyn AsMut<libc::aiocb>>]
+        as *mut [*mut libc::aiocb] as *mut *mut libc::aiocb;
+    let sigev = SigEvent::new(sigev_notify);
+    let sigevp = &mut sigev.sigevent() as *mut libc::sigevent;
+    Errno::result(unsafe {
+        libc::lio_listio(mode as i32, p, list.len() as i32, sigevp)
+    })
+    .map(drop)
+}
+
+#[cfg(test)]
+mod t {
+    use super::*;
+
+    /// aio_suspend relies on casting Rust Aio* struct pointers to libc::aiocb
+    /// pointers.  This test ensures that such casts are valid.
+    #[test]
+    fn casting() {
+        let sev = SigevNotify::SigevNone;
+        let aiof = AioFsync::new(666, AioFsyncMode::O_SYNC, 0, sev);
+        assert_eq!(
+            aiof.as_ref() as *const libc::aiocb,
+            &aiof as *const AioFsync as *const libc::aiocb
+        );
+
+        let mut rbuf = [];
+        let aior = AioRead::new(666, 0, &mut rbuf, 0, sev);
+        assert_eq!(
+            aior.as_ref() as *const libc::aiocb,
+            &aior as *const AioRead as *const libc::aiocb
+        );
+
+        let wbuf = [];
+        let aiow = AioWrite::new(666, 0, &wbuf, 0, sev);
+        assert_eq!(
+            aiow.as_ref() as *const libc::aiocb,
+            &aiow as *const AioWrite as *const libc::aiocb
+        );
+    }
+
+    #[cfg(target_os = "freebsd")]
+    #[test]
+    fn casting_vectored() {
+        let sev = SigevNotify::SigevNone;
+
+        let mut rbuf = [];
+        let mut rbufs = [IoSliceMut::new(&mut rbuf)];
+        let aiorv = AioReadv::new(666, 0, &mut rbufs[..], 0, sev);
+        assert_eq!(
+            aiorv.as_ref() as *const libc::aiocb,
+            &aiorv as *const AioReadv as *const libc::aiocb
+        );
+
+        let wbuf = [];
+        let wbufs = [IoSlice::new(&wbuf)];
+        let aiowv = AioWritev::new(666, 0, &wbufs, 0, sev);
+        assert_eq!(
+            aiowv.as_ref() as *const libc::aiocb,
+            &aiowv as *const AioWritev as *const libc::aiocb
+        );
+    }
+}