Remove the shim kernel crate

kernel/src/syscall/recvmsg.rs

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::SyscallReturn;
+use crate::{
+    fs::file_table::FileDesc,
+    net::socket::SendRecvFlags,
+    prelude::*,
+    util::net::{get_socket_from_fd, CUserMsgHdr},
+};
+
+pub fn sys_recvmsg(
+    sockfd: FileDesc,
+    user_msghdr_ptr: Vaddr,
+    flags: i32,
+    ctx: &Context,
+) -> Result<SyscallReturn> {
+    let c_user_msghdr: CUserMsgHdr = ctx.get_user_space().read_val(user_msghdr_ptr)?;
+    let flags = SendRecvFlags::from_bits_truncate(flags);
+
+    debug!(
+        "sockfd = {}, user_msghdr = {:x?}, flags = {:?}",
+        sockfd, c_user_msghdr, flags
+    );
+
+    let (total_bytes, message_header) = {
+        let socket = get_socket_from_fd(sockfd)?;
+        let io_vecs = c_user_msghdr.copy_iovs_from_user()?;
+        socket.recvmsg(&io_vecs, flags)?
+    };
+
+    if let Some(addr) = message_header.addr() {
+        c_user_msghdr.write_socket_addr_to_user(addr)?;
+    }
+
+    if c_user_msghdr.msg_control != 0 {
+        warn!("receiving control message is not supported");
+    }
+
+    Ok(SyscallReturn::Return(total_bytes as _))
+}