io-uring: add recvmsg

src/io_uring/ops.rs

@@ -2,6 +2,7 @@ use crate::{io_uring::IoUringError, utils::oserror::OsError};
 
 pub mod async_cancel;
 pub mod poll;
+pub mod recvmsg;
 pub mod sendmsg;
 pub mod timeout;
 pub mod write;

src/io_uring/ops/recvmsg.rs

@@ -0,0 +1,131 @@
+use {
+    crate::{
+        io_uring::{
+            pending_result::PendingResult,
+            sys::{io_uring_sqe, IORING_OP_RECVMSG},
+            IoUring, IoUringData, IoUringError, Task,
+        },
+        utils::buf::Buf,
+    },
+    std::{cell::Cell, collections::VecDeque, mem::MaybeUninit, rc::Rc},
+    uapi::{c, OwnedFd},
+};
+
+impl IoUring {
+    pub async fn recvmsg(
+        &self,
+        fd: &Rc<OwnedFd>,
+        bufs: &mut [Buf],
+        fds: &mut VecDeque<OwnedFd>,
+    ) -> Result<usize, IoUringError> {
+        self.ring.check_destroyed()?;
+        let id = self.ring.id();
+        let pr = self.ring.pending_results.acquire();
+        let mut cmsg = self.ring.cmsg_buf();
+        let cmsg_len;
+        {
+            let mut rm = self.ring.cached_recvmsg.pop().unwrap_or_default();
+            rm.iovecs.clear();
+            for buf in bufs {
+                rm.bufs.push(buf.clone());
+                rm.iovecs.push(c::iovec {
+                    iov_base: buf.as_ptr() as _,
+                    iov_len: buf.len() as _,
+                });
+            }
+            rm.id = id.id;
+            rm.fd = fd.raw();
+            rm.msghdr.msg_control = cmsg.as_ptr() as _;
+            rm.msghdr.msg_controllen = cmsg.len() as _;
+            rm.msghdr.msg_iov = rm.iovecs.as_mut_ptr();
+            rm.msghdr.msg_iovlen = rm.iovecs.len() as _;
+            rm.data = Some(Data {
+                _cmsg: cmsg.clone(),
+                _fd: fd.clone(),
+                pr: pr.clone(),
+            });
+            cmsg_len = rm.cmsg_len.clone();
+            self.ring.schedule(rm);
+        }
+        macro_rules! return_cmsg {
+            () => {
+                self.ring.cached_cmsg_bufs.push(cmsg);
+            };
+        }
+        match pr.await {
+            Ok(n) => {
+                let mut cmsg_data = &cmsg[..cmsg_len.get()];
+                while cmsg_data.len() > 0 {
+                    let (_, hdr, data) = match uapi::cmsg_read(&mut cmsg_data) {
+                        Ok(m) => m,
+                        Err(_) => {
+                            return_cmsg!();
+                            return Err(IoUringError::InvalidCmsgData);
+                        }
+                    };
+                    if (hdr.cmsg_level, hdr.cmsg_type) == (c::SOL_SOCKET, c::SCM_RIGHTS) {
+                        fds.extend(uapi::pod_iter(data).unwrap());
+                    }
+                }
+                return_cmsg!();
+                Ok(n as _)
+            }
+            Err(e) => {
+                return_cmsg!();
+                Err(IoUringError::OsError(e))
+            }
+        }
+    }
+}
+
+struct Data {
+    _cmsg: Buf,
+    _fd: Rc<OwnedFd>,
+    pr: PendingResult,
+}
+
+pub struct RecvmsgTask {
+    id: u64,
+    fd: c::c_int,
+    bufs: Vec<Buf>,
+    iovecs: Vec<c::iovec>,
+    msghdr: c::msghdr,
+    cmsg_len: Rc<Cell<usize>>,
+    data: Option<Data>,
+}
+
+impl Default for RecvmsgTask {
+    fn default() -> Self {
+        RecvmsgTask {
+            id: 0,
+            fd: 0,
+            bufs: vec![],
+            iovecs: vec![],
+            msghdr: unsafe { MaybeUninit::zeroed().assume_init() },
+            cmsg_len: Rc::new(Cell::new(0)),
+            data: None,
+        }
+    }
+}
+
+unsafe impl Task for RecvmsgTask {
+    fn id(&self) -> u64 {
+        self.id
+    }
+
+    fn complete(mut self: Box<Self>, ring: &IoUringData, res: i32) {
+        self.cmsg_len.set(self.msghdr.msg_controllen as _);
+        self.bufs.clear();
+        if let Some(data) = self.data.take() {
+            data.pr.complete(res);
+        }
+        ring.cached_recvmsg.push(self);
+    }
+
+    fn encode(&self, sqe: &mut io_uring_sqe) {
+        sqe.opcode = IORING_OP_RECVMSG;
+        sqe.fd = self.fd;
+        sqe.u2.addr = &self.msghdr as *const _ as _;
+        sqe.u3.msg_flags = c::MSG_CMSG_CLOEXEC as _;
+    }
+}