feat(kernel): add Send and Receive IPC syscalls with rendezvous

crates/kernel/src/tests/ipc.rs

@@ -0,0 +1,140 @@
+use super::*;
+use crate::{SyscallOutcome, SyscallResult};
+use domain::message::Message;
+use domain::syscall::Syscall;
+use domain::thread::BlockReason;
+use types::bounded::CapSlot;
+use types::id::ThreadId;
+use types::permission::{Permission, PermissionSet};
+
+fn setup_ipc_kernel() -> (
+    crate::Kernel<MockPlatform>,
+    ProcessId,     // process A
+    ProcessId,     // process B
+    CapSlot,       // endpoint cap for A (Execute perm)
+    CapSlot,       // endpoint cap for B (Read perm)
+    ThreadId,      // thread B id
+) {
+    let (mut k, pid_a) = kernel_with_process();
+
+    // Create process B
+    let proc_b_slot = match k.handle_syscall(Syscall::CreateProcess {
+        create_cap: CapSlot::new(0).unwrap(),
+        image: types::address::DataRef::empty(),
+    }) {
+        SyscallOutcome::Complete(SyscallResult::Slot(s)) => s,
+        _ => panic!("expected slot"),
+    };
+
+    // Get process B's pid from the cap
+    let pid_b = ProcessId::from_raw(1);
+    let tid_b = ThreadId::from_raw(1);
+
+    // Create an endpoint
+    let ep_id = k.create_endpoint_for_test();
+
+    // Grant endpoint caps to both processes
+    let cap_a = k.grant_cap_for_test(
+        pid_a,
+        domain::resource::Resource::Endpoint(ep_id),
+        PermissionSet::empty()
+            .with(Permission::Execute)
+            .with(Permission::Read),
+    );
+
+    let cap_b = k.grant_cap_for_test(
+        pid_b,
+        domain::resource::Resource::Endpoint(ep_id),
+        PermissionSet::empty()
+            .with(Permission::Execute)
+            .with(Permission::Read),
+    );
+
+    (k, pid_a, pid_b, cap_a, cap_b, tid_b)
+}
+
+#[test]
+fn send_without_receiver_blocks_caller() {
+    let (mut k, _, _, cap_a, _, _) = setup_ipc_kernel();
+
+    let msg = Message::from_words([42, 0, 0, 0]);
+    let outcome = k.handle_syscall(Syscall::Send {
+        endpoint: cap_a,
+        message: msg,
+    });
+    assert!(matches!(outcome, SyscallOutcome::BlockCaller(BlockReason::Sending(_))));
+}
+
+#[test]
+fn receive_without_sender_blocks_caller() {
+    let (mut k, _, pid_b, _, cap_b, tid_b) = setup_ipc_kernel();
+
+    // Switch to thread B to call Receive
+    k.switch_to_thread_for_test(tid_b);
+
+    let outcome = k.handle_syscall(Syscall::Receive {
+        endpoint: cap_b,
+    });
+    assert!(matches!(outcome, SyscallOutcome::BlockCaller(BlockReason::Receiving(_))));
+}
+
+#[test]
+fn send_with_waiting_receiver_delivers_and_switches() {
+    let (mut k, pid_a, pid_b, cap_a, cap_b, tid_b) = setup_ipc_kernel();
+    let tid_a = ThreadId::from_raw(0);
+
+    // Thread B calls Receive first (blocks)
+    k.switch_to_thread_for_test(tid_b);
+    k.handle_syscall(Syscall::Receive { endpoint: cap_b });
+
+    // Thread A sends
+    k.switch_to_thread_for_test(tid_a);
+    let msg = Message::from_words([42, 0, 0, 0]);
+    let outcome = k.handle_syscall(Syscall::Send {
+        endpoint: cap_a,
+        message: msg,
+    });
+
+    // Should switch to the receiver
+    assert!(matches!(outcome, SyscallOutcome::SwitchTo(t) if t == tid_b));
+
+    // Receiver should have pending message
+    let result = k.pending_result(tid_b);
+    assert!(result.is_some());
+}
+
+#[test]
+fn receive_with_waiting_sender_delivers_immediately() {
+    let (mut k, pid_a, pid_b, cap_a, cap_b, tid_b) = setup_ipc_kernel();
+    let tid_a = ThreadId::from_raw(0);
+
+    // Thread A sends first (blocks)
+    let msg = Message::from_words([99, 0, 0, 0]);
+    k.handle_syscall(Syscall::Send {
+        endpoint: cap_a,
+        message: msg,
+    });
+
+    // Thread B calls Receive (should get message immediately)
+    k.switch_to_thread_for_test(tid_b);
+    let outcome = k.handle_syscall(Syscall::Receive { endpoint: cap_b });
+
+    assert!(matches!(
+        outcome,
+        SyscallOutcome::Complete(SyscallResult::Message(m)) if m.word(0) == 99
+    ));
+}
+
+#[test]
+fn send_checks_endpoint_capability() {
+    let (mut k, _, _, _, _, _) = setup_ipc_kernel();
+    // slot 10 doesn't exist
+    let outcome = k.handle_syscall(Syscall::Send {
+        endpoint: CapSlot::new(10).unwrap(),
+        message: Message::empty(),
+    });
+    assert!(matches!(
+        outcome,
+        SyscallOutcome::Complete(SyscallResult::Error(_))
+    ));
+}

crates/kernel/src/tests/mod.rs

@@ -1,5 +1,6 @@
 mod capability;
 mod exit;
+mod ipc;
 mod lifecycle;
 mod memory;
 mod simple;