Remove the shim kernel crate

kernel/src/syscall/getcwd.rs

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::SyscallReturn;
+use crate::prelude::*;
+
+pub fn sys_getcwd(buf: Vaddr, len: usize, ctx: &Context) -> Result<SyscallReturn> {
+    // TODO: getcwd only return a fake result now
+    let fake_cwd = CString::new("/")?;
+    let bytes = fake_cwd.as_bytes_with_nul();
+    let write_len = len.min(bytes.len());
+    ctx.get_user_space()
+        .write_bytes(buf, &mut VmReader::from(&bytes[..write_len]))?;
+    Ok(SyscallReturn::Return(write_len as _))
+}