Remove the shim kernel crate

kernel/src/syscall/wait4.rs

@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::{getrusage::rusage_t, SyscallReturn};
+use crate::{
+    prelude::*,
+    process::{wait_child_exit, ProcessFilter, WaitOptions},
+};
+
+pub fn sys_wait4(
+    wait_pid: u64,
+    exit_status_ptr: u64,
+    wait_options: u32,
+    rusage_addr: Vaddr,
+    ctx: &Context,
+) -> Result<SyscallReturn> {
+    let wait_options = WaitOptions::from_bits(wait_options)
+        .ok_or_else(|| Error::with_message(Errno::EINVAL, "unknown wait option"))?;
+    debug!(
+        "pid = {}, exit_status_ptr = {}, wait_options: {:?}",
+        wait_pid as i32, exit_status_ptr, wait_options
+    );
+    debug!("wait4 current pid = {}", ctx.process.pid());
+    let process_filter = ProcessFilter::from_id(wait_pid as _);
+
+    let waited_process = wait_child_exit(process_filter, wait_options)?;
+    let Some(process) = waited_process else {
+        return Ok(SyscallReturn::Return(0 as _));
+    };
+
+    let (return_pid, exit_code) = (process.pid(), process.exit_code().unwrap());
+    if exit_status_ptr != 0 {
+        ctx.get_user_space()
+            .write_val(exit_status_ptr as _, &exit_code)?;
+    }
+
+    if rusage_addr != 0 {
+        let rusage = rusage_t {
+            ru_utime: process.prof_clock().user_clock().read_time().into(),
+            ru_stime: process.prof_clock().kernel_clock().read_time().into(),
+            ..Default::default()
+        };
+
+        ctx.get_user_space().write_val(rusage_addr, &rusage)?;
+    }
+
+    Ok(SyscallReturn::Return(return_pid as _))
+}