Recover wait/sleep

crate/process/src/process_manager.rs

@@ -3,6 +3,8 @@ use alloc::sync::Arc;
 use spin::Mutex;
 use scheduler::Scheduler;
 use core::cell::UnsafeCell;
+use alloc::vec::Vec;
+use event_hub::EventHub;
 
 struct Process {
     id: Pid,
@@ -20,10 +22,15 @@ pub enum Status {
     Ready,
     Running(usize),
     Sleeping,
+    Waiting(Pid),
     /// aka ZOMBIE. Its context was dropped.
     Exited(ExitCode),
 }
 
+enum Event {
+    Wakeup(Pid),
+}
+
 pub trait Context {
     unsafe fn switch_to(&mut self, target: &mut Context);
 }
@@ -31,6 +38,8 @@ pub trait Context {
 pub struct ProcessManager {
     procs: [Mutex<Option<Process>>; MAX_PROC_NUM],
     scheduler: Mutex<Box<Scheduler>>,
+    wait_queue: [Mutex<Vec<Pid>>; MAX_PROC_NUM],
+    event_hub: Mutex<EventHub<Event>>,
 }
 
 impl ProcessManager {
@@ -38,6 +47,8 @@ impl ProcessManager {
         ProcessManager {
             procs: Default::default(),
             scheduler: Mutex::new(scheduler),
+            wait_queue: Default::default(),
+            event_hub: Mutex::new(EventHub::new()),
         }
     }
 
@@ -53,7 +64,6 @@ impl ProcessManager {
     /// Add a new process
     pub fn add(&self, context: Box<Context>) -> Pid {
         let pid = self.alloc_pid();
-        // TODO: check parent
         *self.procs[pid].lock() = Some(Process {
             id: pid,
             status: Status::Ready,
@@ -68,6 +78,13 @@ impl ProcessManager {
     /// Return true if time slice == 0.
     /// Called by timer interrupt handler.
     pub fn tick(&self, pid: Pid) -> bool {
+        let mut event_hub = self.event_hub.lock();
+        event_hub.tick();
+        while let Some(event) = event_hub.pop() {
+            match event {
+                Event::Wakeup(pid) => self.set_status(pid, Status::Ready),
+            }
+        }
         self.scheduler.lock().tick(pid)
     }
 
@@ -107,18 +124,22 @@ impl ProcessManager {
 
     /// Switch the status of a process.
     /// Insert/Remove it to/from scheduler if necessary.
-    pub fn set_status(&self, pid: Pid, status: Status) {
+    fn set_status(&self, pid: Pid, status: Status) {
         let mut scheduler = self.scheduler.lock();
         let mut proc_lock = self.procs[pid].lock();
         let mut proc = proc_lock.as_mut().unwrap();
+        trace!("process {} {:?} -> {:?}", pid, proc.status, status);
         match (&proc.status, &status) {
             (Status::Ready, Status::Ready) => return,
             (Status::Ready, _) => scheduler.remove(pid),
             (Status::Running(_), _) => {},
+            (Status::Exited(_), _) => panic!("can not set status for a exited process"),
+            (Status::Waiting(target), Status::Exited(_)) =>
+                self.wait_queue[*target].lock().retain(|&i| i != pid),
+            // TODO: Sleep -> Exited  Remove wakeup event.
             (_, Status::Ready) => scheduler.insert(pid),
             _ => {}
         }
-        trace!("process {} {:?} -> {:?}", pid, proc.status, status);
         match proc.status {
             Status::Running(_) => proc.status_after_stop = status,
             _ => proc.status = status,
@@ -128,4 +149,41 @@ impl ProcessManager {
             _ => {}
         }
     }
+
+
+    pub fn get_status(&self, pid: Pid) -> Option<Status> {
+        self.procs[pid].lock().as_ref().map(|p| p.status.clone())
+    }
+
+    pub fn remove(&self, pid: Pid) {
+        let mut proc_lock = self.procs[pid].lock();
+        let proc = proc_lock.as_ref().unwrap();
+        match proc.status {
+            Status::Exited(_) => *proc_lock = None,
+            _ => panic!("can not remove non-exited process"),
+        }
+    }
+
+    pub fn sleep(&self, pid: Pid, time: usize) {
+        self.set_status(pid, Status::Sleeping);
+        if time != 0 {
+            self.event_hub.lock().push(time, Event::Wakeup(pid));
+        }
+    }
+
+    pub fn wakeup(&self, pid: Pid) {
+        self.set_status(pid, Status::Ready);
+    }
+
+    pub fn wait(&self, pid: Pid, target: Pid) {
+        self.set_status(pid, Status::Waiting(target));
+        self.wait_queue[target].lock().push(pid);
+    }
+
+    pub fn exit(&self, pid: Pid, code: ExitCode) {
+        self.set_status(pid, Status::Exited(code));
+        for waiter in self.wait_queue[pid].lock().drain(..) {
+            self.wakeup(waiter);
+        }
+    }
 }

crate/process/src/thread.rs

@@ -41,7 +41,7 @@ pub fn current() -> Thread {
 pub fn sleep(dur: Duration) {
     let time = dur_to_ticks(dur);
     info!("sleep: {:?} ticks", time);
-    // TODO: register wakeup
+    processor().manager().sleep(current().id(), time);
     park();
 
     fn dur_to_ticks(dur: Duration) -> usize {
@@ -87,9 +87,8 @@ pub fn spawn<F, T>(f: F) -> JoinHandle<T>
         //   unsafe { LocalKey::<usize>::get_map() }.clear();
         // 让Processor退出当前线程
         // 把f返回值在堆上的指针，以线程返回码的形式传递出去
-        let pid = processor().pid();
         let exit_code = Box::into_raw(ret) as usize;
-        processor().manager().set_status(pid, Status::Exited(exit_code));
+        processor().manager().exit(current().id(), exit_code);
         processor().yield_now();
         // 再也不会被调度回来了
         unreachable!()
@@ -116,8 +115,7 @@ pub fn yield_now() {
 /// Blocks unless or until the current thread's token is made available.
 pub fn park() {
     info!("park:");
-    let pid = processor().pid();
-    processor().manager().set_status(pid, Status::Sleeping);
+    processor().manager().sleep(current().id(), 0);
     processor().yield_now();
 }
 
@@ -129,7 +127,7 @@ pub struct Thread {
 impl Thread {
     /// Atomically makes the handle's token available if it is not already.
     pub fn unpark(&self) {
-        processor().manager().set_status(self.pid, Status::Ready);
+        processor().manager().wakeup(self.pid);
     }
     /// Gets the thread's unique identifier.
     pub fn id(&self) -> usize {
@@ -150,8 +148,19 @@ impl<T> JoinHandle<T> {
     }
     /// Waits for the associated thread to finish.
     pub fn join(self) -> Result<T, ()> {
-        // TODO: wait for the thread
-        unimplemented!()
+        loop {
+            match processor().manager().get_status(self.thread.pid) {
+                Some(Status::Exited(exit_code)) => {
+                    processor().manager().remove(self.thread.pid);
+                    // Find return value on the heap from the exit code.
+                    return Ok(unsafe { *Box::from_raw(exit_code as *mut T) });
+                }
+                None => return Err(()),
+                _ => {}
+            }
+            processor().manager().wait(current().id(), self.thread.pid);
+            processor().yield_now();
+        }
     }
 }
 

kernel/src/fs.rs

@@ -46,8 +46,9 @@ pub fn shell() {
         if let Ok(file) = root.borrow().lookup(name.as_str()) {
             use process::*;
             let len = file.borrow().read_at(0, &mut *buf).unwrap();
-            processor().manager().add(ContextImpl::new_user(&buf[..len]));
-            // TODO: wait for new process
+            let pid = processor().manager().add(ContextImpl::new_user(&buf[..len]));
+            processor().manager().wait(thread::current().id(), pid);
+            processor().yield_now();
         } else {
             println!("Program not exist");
         }

kernel/src/syscall.rs

@@ -68,7 +68,22 @@ fn sys_fork(tf: &TrapFrame) -> i32 {
 /// Wait the process exit.
 /// Return the PID. Store exit code to `code` if it's not null.
 fn sys_wait(pid: usize, code: *mut i32) -> i32 {
-    unimplemented!();
+    assert_ne!(pid, 0, "wait for 0 is not supported yet");
+    loop {
+        match processor().manager().get_status(pid) {
+            Some(Status::Exited(exit_code)) => {
+                if !code.is_null() {
+                    unsafe { code.write(exit_code as i32); }
+                }
+                processor().manager().remove(pid);
+                return 0;
+            }
+            None => return -1,
+            _ => {}
+        }
+        processor().manager().wait(thread::current().id(), pid);
+        processor().yield_now();
+    }
 }
 
 fn sys_yield() -> i32 {
@@ -78,7 +93,7 @@ fn sys_yield() -> i32 {
 
 /// Kill the process
 fn sys_kill(pid: usize) -> i32 {
-    processor().manager().set_status(pid, Status::Exited(0x100));
+    processor().manager().exit(pid, 0x100);
     0
 }
 
@@ -90,9 +105,9 @@ fn sys_getpid() -> i32 {
 /// Exit the current process
 fn sys_exit(exit_code: usize) -> i32 {
     let pid = thread::current().id();
-    processor().manager().set_status(pid, Status::Exited(exit_code));
+    processor().manager().exit(pid, exit_code);
     processor().yield_now();
-    0
+    unreachable!();
 }
 
 fn sys_sleep(time: usize) -> i32 {
@@ -102,7 +117,7 @@ fn sys_sleep(time: usize) -> i32 {
 }
 
 fn sys_get_time() -> i32 {
-    unimplemented!();
+    unsafe { ::trap::TICK as i32 }
 }
 
 fn sys_lab6_set_priority(priority: usize) -> i32 {

kernel/src/trap.rs

@@ -2,8 +2,13 @@ use process::*;
 use arch::interrupt::TrapFrame;
 use arch::cpu;
 
+pub static mut TICK: usize = 0;
+
 pub fn timer() {
     processor().tick();
+    if cpu::id() == 0 {
+        unsafe { TICK += 1; }
+    }
 }
 
 pub fn before_return() {
@@ -13,7 +18,7 @@ pub fn error(tf: &TrapFrame) -> ! {
     let pid = processor().pid();
     error!("On CPU{} Process {}:\n{:#x?}", cpu::id(), pid, tf);
 
-    processor().manager().set_status(pid, Status::Exited(0x100));
+    processor().manager().exit(pid, 0x100);
     processor().yield_now();
     unreachable!();
 }