Remove the shim kernel crate

kernel/src/syscall/sendto.rs

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::SyscallReturn;
+use crate::{
+    fs::file_table::FileDesc,
+    net::socket::{MessageHeader, SendRecvFlags},
+    prelude::*,
+    util::{
+        net::{get_socket_from_fd, read_socket_addr_from_user},
+        IoVec,
+    },
+};
+
+pub fn sys_sendto(
+    sockfd: FileDesc,
+    buf: Vaddr,
+    len: usize,
+    flags: i32,
+    dest_addr: Vaddr,
+    addrlen: usize,
+    _ctx: &Context,
+) -> Result<SyscallReturn> {
+    let flags = SendRecvFlags::from_bits_truncate(flags);
+    let socket_addr = if dest_addr == 0 {
+        None
+    } else {
+        let socket_addr = read_socket_addr_from_user(dest_addr, addrlen)?;
+        Some(socket_addr)
+    };
+    debug!("sockfd = {sockfd}, buf = 0x{buf:x}, len = 0x{len:x}, flags = {flags:?}, socket_addr = {socket_addr:?}");
+
+    let socket = get_socket_from_fd(sockfd)?;
+
+    let io_vecs = [IoVec::new(buf, len)];
+    let message_header = MessageHeader::new(socket_addr, None);
+
+    let send_size = socket.sendmsg(&io_vecs, message_header, flags)?;
+
+    Ok(SyscallReturn::Return(send_size as _))
+}