1 files changed, 358 insertions, 0 deletions
diff --git a/third_party/rust/nix/src/mqueue.rs b/third_party/rust/nix/src/mqueue.rs
new file mode 100644
index 0000000000..fb07d2accb
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+++ b/third_party/rust/nix/src/mqueue.rs
@@ -0,0 +1,358 @@
+//! Posix Message Queue functions
+//!
+//! # Example
+//!
+// no_run because a kernel module may be required.
+//! ```no_run
+//! # use std::ffi::CString;
+//! # use nix::mqueue::*;
+//! use nix::sys::stat::Mode;
+//!
+//! const MSG_SIZE: mq_attr_member_t = 32;
+//! let mq_name= "/a_nix_test_queue";
+//!
+//! let oflag0 = MQ_OFlag::O_CREAT | MQ_OFlag::O_WRONLY;
+//! let mode = Mode::S_IWUSR | Mode::S_IRUSR | Mode::S_IRGRP | Mode::S_IROTH;
+//! let mqd0 = mq_open(mq_name, oflag0, mode, None).unwrap();
+//! let msg_to_send = b"msg_1";
+//! mq_send(&mqd0, msg_to_send, 1).unwrap();
+//!
+//! let oflag1 = MQ_OFlag::O_CREAT | MQ_OFlag::O_RDONLY;
+//! let mqd1 = mq_open(mq_name, oflag1, mode, None).unwrap();
+//! let mut buf = [0u8; 32];
+//! let mut prio = 0u32;
+//! let len = mq_receive(&mqd1, &mut buf, &mut prio).unwrap();
+//! assert_eq!(prio, 1);
+//! assert_eq!(msg_to_send, &buf[0..len]);
+//!
+//! mq_close(mqd1).unwrap();
+//! mq_close(mqd0).unwrap();
+//! ```
+//! [Further reading and details on the C API](https://man7.org/linux/man-pages/man7/mq_overview.7.html)
+
+use crate::errno::Errno;
+use crate::NixPath;
+use crate::Result;
+
+use crate::sys::stat::Mode;
+use libc::{self, c_char, mqd_t, size_t};
+use std::mem;
+#[cfg(any(
+    target_os = "linux",
+    target_os = "netbsd",
+    target_os = "dragonfly"
+))]
+use std::os::unix::io::{
+    AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd,
+};
+
+libc_bitflags! {
+    /// Used with [`mq_open`].
+    pub struct MQ_OFlag: libc::c_int {
+        /// Open the message queue for receiving messages.
+        O_RDONLY;
+        /// Open the queue for sending messages.
+        O_WRONLY;
+        /// Open the queue for both receiving and sending messages
+        O_RDWR;
+        /// Create a message queue.
+        O_CREAT;
+        /// If set along with `O_CREAT`, `mq_open` will fail if the message
+        /// queue name exists.
+        O_EXCL;
+        /// `mq_send` and `mq_receive` should fail with `EAGAIN` rather than
+        /// wait for resources that are not currently available.
+        O_NONBLOCK;
+        /// Set the close-on-exec flag for the message queue descriptor.
+        O_CLOEXEC;
+    }
+}
+
+/// A message-queue attribute, optionally used with [`mq_setattr`] and
+/// [`mq_getattr`] and optionally [`mq_open`],
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+pub struct MqAttr {
+    mq_attr: libc::mq_attr,
+}
+
+/// Identifies an open POSIX Message Queue
+// A safer wrapper around libc::mqd_t, which is a pointer on some platforms
+// Deliberately is not Clone to prevent use-after-close scenarios
+#[repr(transparent)]
+#[derive(Debug)]
+#[allow(missing_copy_implementations)]
+pub struct MqdT(mqd_t);
+
+// x32 compatibility
+// See https://sourceware.org/bugzilla/show_bug.cgi?id=21279
+/// Size of a message queue attribute member
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "32"))]
+#[cfg_attr(docsrs, doc(cfg(all())))]
+pub type mq_attr_member_t = i64;
+/// Size of a message queue attribute member
+#[cfg(not(all(target_arch = "x86_64", target_pointer_width = "32")))]
+#[cfg_attr(docsrs, doc(cfg(all())))]
+pub type mq_attr_member_t = libc::c_long;
+
+impl MqAttr {
+    /// Create a new message queue attribute
+    ///
+    /// # Arguments
+    ///
+    /// - `mq_flags`:   Either `0` or `O_NONBLOCK`.
+    /// - `mq_maxmsg`:  Maximum number of messages on the queue.
+    /// - `mq_msgsize`: Maximum message size in bytes.
+    /// - `mq_curmsgs`: Number of messages currently in the queue.
+    pub fn new(
+        mq_flags: mq_attr_member_t,
+        mq_maxmsg: mq_attr_member_t,
+        mq_msgsize: mq_attr_member_t,
+        mq_curmsgs: mq_attr_member_t,
+    ) -> MqAttr {
+        let mut attr = mem::MaybeUninit::<libc::mq_attr>::uninit();
+        unsafe {
+            let p = attr.as_mut_ptr();
+            (*p).mq_flags = mq_flags;
+            (*p).mq_maxmsg = mq_maxmsg;
+            (*p).mq_msgsize = mq_msgsize;
+            (*p).mq_curmsgs = mq_curmsgs;
+            MqAttr {
+                mq_attr: attr.assume_init(),
+            }
+        }
+    }
+
+    /// The current flags, either `0` or `O_NONBLOCK`.
+    pub const fn flags(&self) -> mq_attr_member_t {
+        self.mq_attr.mq_flags
+    }
+
+    /// The max number of messages that can be held by the queue
+    pub const fn maxmsg(&self) -> mq_attr_member_t {
+        self.mq_attr.mq_maxmsg
+    }
+
+    /// The maximum size of each message (in bytes)
+    pub const fn msgsize(&self) -> mq_attr_member_t {
+        self.mq_attr.mq_msgsize
+    }
+
+    /// The number of messages currently held in the queue
+    pub const fn curmsgs(&self) -> mq_attr_member_t {
+        self.mq_attr.mq_curmsgs
+    }
+}
+
+/// Open a message queue
+///
+/// See also [`mq_open(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_open.html)
+// The mode.bits() cast is only lossless on some OSes
+#[allow(clippy::cast_lossless)]
+pub fn mq_open<P>(
+    name: &P,
+    oflag: MQ_OFlag,
+    mode: Mode,
+    attr: Option<&MqAttr>,
+) -> Result<MqdT>
+where
+    P: ?Sized + NixPath,
+{
+    let res = name.with_nix_path(|cstr| match attr {
+        Some(mq_attr) => unsafe {
+            libc::mq_open(
+                cstr.as_ptr(),
+                oflag.bits(),
+                mode.bits() as libc::c_int,
+                &mq_attr.mq_attr as *const libc::mq_attr,
+            )
+        },
+        None => unsafe { libc::mq_open(cstr.as_ptr(), oflag.bits()) },
+    })?;
+
+    Errno::result(res).map(MqdT)
+}
+
+/// Remove a message queue
+///
+/// See also [`mq_unlink(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_unlink.html)
+pub fn mq_unlink<P>(name: &P) -> Result<()>
+where
+    P: ?Sized + NixPath,
+{
+    let res =
+        name.with_nix_path(|cstr| unsafe { libc::mq_unlink(cstr.as_ptr()) })?;
+    Errno::result(res).map(drop)
+}
+
+/// Close a message queue
+///
+/// See also [`mq_close(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_close.html)
+pub fn mq_close(mqdes: MqdT) -> Result<()> {
+    let res = unsafe { libc::mq_close(mqdes.0) };
+    Errno::result(res).map(drop)
+}
+
+/// Receive a message from a message queue
+///
+/// See also [`mq_receive(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_receive.html)
+pub fn mq_receive(
+    mqdes: &MqdT,
+    message: &mut [u8],
+    msg_prio: &mut u32,
+) -> Result<usize> {
+    let len = message.len() as size_t;
+    let res = unsafe {
+        libc::mq_receive(
+            mqdes.0,
+            message.as_mut_ptr() as *mut c_char,
+            len,
+            msg_prio as *mut u32,
+        )
+    };
+    Errno::result(res).map(|r| r as usize)
+}
+
+feature! {
+    #![feature = "time"]
+    use crate::sys::time::TimeSpec;
+    /// Receive a message from a message queue with a timeout
+    ///
+    /// See also ['mq_timedreceive(2)'](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_receive.html)
+    pub fn mq_timedreceive(
+        mqdes: &MqdT,
+        message: &mut [u8],
+        msg_prio: &mut u32,
+        abstime: &TimeSpec,
+    ) -> Result<usize> {
+        let len = message.len() as size_t;
+        let res = unsafe {
+            libc::mq_timedreceive(
+                mqdes.0,
+                message.as_mut_ptr() as *mut c_char,
+                len,
+                msg_prio as *mut u32,
+                abstime.as_ref(),
+            )
+        };
+        Errno::result(res).map(|r| r as usize)
+    }
+}
+
+/// Send a message to a message queue
+///
+/// See also [`mq_send(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_send.html)
+pub fn mq_send(mqdes: &MqdT, message: &[u8], msq_prio: u32) -> Result<()> {
+    let res = unsafe {
+        libc::mq_send(
+            mqdes.0,
+            message.as_ptr() as *const c_char,
+            message.len(),
+            msq_prio,
+        )
+    };
+    Errno::result(res).map(drop)
+}
+
+/// Get message queue attributes
+///
+/// See also [`mq_getattr(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_getattr.html)
+pub fn mq_getattr(mqd: &MqdT) -> Result<MqAttr> {
+    let mut attr = mem::MaybeUninit::<libc::mq_attr>::uninit();
+    let res = unsafe { libc::mq_getattr(mqd.0, attr.as_mut_ptr()) };
+    Errno::result(res).map(|_| unsafe {
+        MqAttr {
+            mq_attr: attr.assume_init(),
+        }
+    })
+}
+
+/// Set the attributes of the message queue. Only `O_NONBLOCK` can be set, everything else will be ignored
+/// Returns the old attributes
+/// It is recommend to use the `mq_set_nonblock()` and `mq_remove_nonblock()` convenience functions as they are easier to use
+///
+/// [Further reading](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_setattr.html)
+pub fn mq_setattr(mqd: &MqdT, newattr: &MqAttr) -> Result<MqAttr> {
+    let mut attr = mem::MaybeUninit::<libc::mq_attr>::uninit();
+    let res = unsafe {
+        libc::mq_setattr(
+            mqd.0,
+            &newattr.mq_attr as *const libc::mq_attr,
+            attr.as_mut_ptr(),
+        )
+    };
+    Errno::result(res).map(|_| unsafe {
+        MqAttr {
+            mq_attr: attr.assume_init(),
+        }
+    })
+}
+
+/// Convenience function.
+/// Sets the `O_NONBLOCK` attribute for a given message queue descriptor
+/// Returns the old attributes
+#[allow(clippy::useless_conversion)] // Not useless on all OSes
+pub fn mq_set_nonblock(mqd: &MqdT) -> Result<MqAttr> {
+    let oldattr = mq_getattr(mqd)?;
+    let newattr = MqAttr::new(
+        mq_attr_member_t::from(MQ_OFlag::O_NONBLOCK.bits()),
+        oldattr.mq_attr.mq_maxmsg,
+        oldattr.mq_attr.mq_msgsize,
+        oldattr.mq_attr.mq_curmsgs,
+    );
+    mq_setattr(mqd, &newattr)
+}
+
+/// Convenience function.
+/// Removes `O_NONBLOCK` attribute for a given message queue descriptor
+/// Returns the old attributes
+pub fn mq_remove_nonblock(mqd: &MqdT) -> Result<MqAttr> {
+    let oldattr = mq_getattr(mqd)?;
+    let newattr = MqAttr::new(
+        0,
+        oldattr.mq_attr.mq_maxmsg,
+        oldattr.mq_attr.mq_msgsize,
+        oldattr.mq_attr.mq_curmsgs,
+    );
+    mq_setattr(mqd, &newattr)
+}
+
+#[cfg(any(target_os = "linux", target_os = "netbsd", target_os = "dragonfly"))]
+impl AsFd for MqdT {
+    /// Borrow the underlying message queue descriptor.
+    fn as_fd(&self) -> BorrowedFd {
+        // SAFETY: [MqdT] will only contain a valid fd by construction.
+        unsafe { BorrowedFd::borrow_raw(self.0) }
+    }
+}
+
+#[cfg(any(target_os = "linux", target_os = "netbsd", target_os = "dragonfly"))]
+impl AsRawFd for MqdT {
+    /// Return the underlying message queue descriptor.
+    ///
+    /// Returned descriptor is a "shallow copy" of the descriptor, so it refers
+    ///  to the same underlying kernel object as `self`.
+    fn as_raw_fd(&self) -> RawFd {
+        self.0
+    }
+}
+
+#[cfg(any(target_os = "linux", target_os = "netbsd", target_os = "dragonfly"))]
+impl FromRawFd for MqdT {
+    /// Construct an [MqdT] from [RawFd].
+    ///
+    /// # Safety
+    /// The `fd` given must be a valid and open file descriptor for a message
+    ///  queue.
+    unsafe fn from_raw_fd(fd: RawFd) -> MqdT {
+        MqdT(fd)
+    }
+}
+
+#[cfg(any(target_os = "linux", target_os = "netbsd", target_os = "dragonfly"))]
+impl IntoRawFd for MqdT {
+    /// Consume this [MqdT] and return a [RawFd].
+    fn into_raw_fd(self) -> RawFd {
+        self.0
+    }
+}