Remove the shim kernel crate

kernel/src/syscall/waitid.rs

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::SyscallReturn;
+use crate::{
+    prelude::*,
+    process::{wait_child_exit, ProcessFilter, WaitOptions},
+};
+
+pub fn sys_waitid(
+    which: u64,
+    upid: u64,
+    _infoq_addr: u64,
+    options: u64,
+    _rusage_addr: u64,
+    _ctx: &Context,
+) -> Result<SyscallReturn> {
+    // FIXME: what does infoq and rusage use for?
+    let process_filter = ProcessFilter::from_which_and_id(which, upid)?;
+    let wait_options = WaitOptions::from_bits(options as u32)
+        .ok_or(Error::with_message(Errno::EINVAL, "invalid options"))?;
+    let waited_process = wait_child_exit(process_filter, wait_options)?;
+    let pid = waited_process.map_or(0, |process| process.pid());
+    Ok(SyscallReturn::Return(pid as _))
+}