Remove the shim kernel crate

kernel/src/syscall/sched_getaffinity.rs

@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use core::{cmp, mem};
+
+use super::SyscallReturn;
+use crate::{
+    prelude::*,
+    process::{process_table, Pid},
+};
+
+fn get_num_cpus() -> usize {
+    // TODO: Properly determine the number of available CPUs
+    // This could be through a system configuration query.
+    1
+}
+
+pub fn sys_sched_getaffinity(
+    pid: Pid,
+    cpuset_size: usize,
+    cpu_set_ptr: Vaddr,
+    ctx: &Context,
+) -> Result<SyscallReturn> {
+    let num_cpus = get_num_cpus();
+
+    if cpuset_size < core::mem::size_of::<cpu_set_t>() {
+        return Err(Error::with_message(Errno::EINVAL, "invalid cpuset size"));
+    }
+
+    match pid {
+        0 => {
+            // TODO: Get the current thread's CPU affinity
+            // Placeholder for future implementation.
+        }
+        _ => {
+            match process_table::get_process(pid) {
+                Some(_process) => { /* Placeholder if process-specific logic needed */ }
+                None => return Err(Error::with_message(Errno::ESRCH, "process does not exist")),
+            }
+        }
+    }
+
+    let dummy_cpu_set = cpu_set_t::new(num_cpus);
+
+    ctx.get_user_space()
+        .write_val(cpu_set_ptr, &dummy_cpu_set)?;
+
+    Ok(SyscallReturn::Return(0))
+}
+
+const CPU_SETSIZE: usize = 1024; // Max number of CPU bits.
+const __NCPUBITS: usize = 8 * mem::size_of::<usize>();
+
+#[derive(Debug, Clone, Copy, Pod)]
+#[repr(C, packed)]
+struct cpu_set_t {
+    __bits: [usize; CPU_SETSIZE / __NCPUBITS],
+}
+
+impl cpu_set_t {
+    /// Creates a new cpu_set_t representing available CPUs.
+    fn new(num_cpus: usize) -> Self {
+        let mut bits = [0usize; CPU_SETSIZE / __NCPUBITS];
+
+        for cpu in 0..cmp::min(num_cpus, CPU_SETSIZE) {
+            bits[cpu / __NCPUBITS] |= 1 << (cpu % __NCPUBITS);
+        }
+
+        Self { __bits: bits }
+    }
+}