Remove the shim kernel crate

kernel/src/syscall/setreuid.rs

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::SyscallReturn;
+use crate::{prelude::*, process::Uid};
+
+pub fn sys_setreuid(ruid: i32, euid: i32, ctx: &Context) -> Result<SyscallReturn> {
+    debug!("ruid = {}, euid = {}", ruid, euid);
+
+    let ruid = if ruid > 0 {
+        Some(Uid::new(ruid as u32))
+    } else {
+        None
+    };
+
+    let euid = if euid > 0 {
+        Some(Uid::new(euid as u32))
+    } else {
+        None
+    };
+
+    let credentials = ctx.posix_thread.credentials_mut();
+    credentials.set_reuid(ruid, euid)?;
+
+    Ok(SyscallReturn::Return(0))
+}