Add signal support - exit on signal

kernel/context/context.rs

@@ -1,6 +1,6 @@
 use alloc::arc::Arc;
 use alloc::boxed::Box;
-use collections::{BTreeMap, Vec};
+use collections::{BTreeMap, Vec, VecDeque};
 use spin::Mutex;
 
 use arch;
@@ -48,6 +48,8 @@ pub struct Context {
     pub vfork: bool,
     /// Context is being waited on
     pub waitpid: Arc<WaitMap<ContextId, usize>>,
+    /// Context should handle pending signals
+    pub pending: VecDeque<u8>,
     /// Context should wake up at specified time
     pub wake: Option<(u64, u64)>,
     /// The architecture specific context
@@ -94,6 +96,7 @@ impl Context {
             cpu_id: None,
             vfork: false,
             waitpid: Arc::new(WaitMap::new()),
+            pending: VecDeque::new(),
             wake: None,
             arch: arch::context::Context::new(),
             kfx: None,

kernel/context/switch.rs

@@ -1,7 +1,8 @@
 use core::sync::atomic::Ordering;
 
 use arch;
-use super::{contexts, Context, Status, CONTEXT_ID};
+use context::{contexts, Context, Status, CONTEXT_ID};
+use syscall;
 
 /// Switch to the next context
 ///
@@ -20,6 +21,7 @@ pub unsafe fn switch() -> bool {
 
     let from_ptr;
     let mut to_ptr = 0 as *mut Context;
+    let mut to_sig = None;
     {
         let contexts = contexts();
         {
@@ -34,6 +36,10 @@ pub unsafe fn switch() -> bool {
                 // println!("{}: take {} {}", cpu_id, context.id, ::core::str::from_utf8_unchecked(&context.name.lock()));
             }
 
+            if context.status == Status::Blocked && ! context.pending.is_empty() {
+                context.unblock();
+            }
+
             if context.status == Status::Blocked && context.wake.is_some() {
                 let wake = context.wake.expect("context::switch: wake not set");
 
@@ -57,6 +63,7 @@ pub unsafe fn switch() -> bool {
                 let mut context = context_lock.write();
                 if check_context(&mut context) {
                     to_ptr = context.deref_mut() as *mut Context;
+                    to_sig = context.pending.pop_front();
                     break;
                 }
             }
@@ -68,6 +75,7 @@ pub unsafe fn switch() -> bool {
                     let mut context = context_lock.write();
                     if check_context(&mut context) {
                         to_ptr = context.deref_mut() as *mut Context;
+                        to_sig = context.pending.pop_front();
                         break;
                     }
                 }
@@ -91,7 +99,17 @@ pub unsafe fn switch() -> bool {
     // Unset global lock before switch, as arch is only usable by the current CPU at this time
     arch::context::CONTEXT_SWITCH_LOCK.store(false, Ordering::SeqCst);
 
+    if let Some(sig) = to_sig {
+        println!("Handle {}", sig);
+        (&mut *to_ptr).arch.signal_stack(signal_handler, sig);
+    }
+
     (&mut *from_ptr).arch.switch_to(&mut (&mut *to_ptr).arch);
 
     true
 }
+
+extern fn signal_handler(signal: usize) {
+    println!("Signal handler: {}", signal);
+    syscall::exit(signal);
+}