2 files changed, 70 insertions, 2 deletions

diff --git a/src/sys/os/os_proc.c b/src/sys/os/os_proc.c
index 971a6c0..4ee4fd8 100644
--- a/src/sys/os/os_proc.c
+++ b/src/sys/os/os_proc.c
@@ -169,6 +169,43 @@ proc_clear_ranges(struct proc *proc)
 }
 
 /*
+ * Put a process to sleep
+ */
+int
+proc_sleep(struct proc *proc)
+{
+    struct pcore *core = this_core();
+
+    if (proc == NULL || core == NULL) {
+        return -EINVAL;
+    }
+
+    proc->flags |= PROC_SLEEPING;
+    md_proc_sleep();
+    return 0;
+}
+
+/*
+ * Wake up a process
+ */
+int
+proc_wake(struct proc *proc)
+{
+    struct pcore *core = cpu_sched();
+
+    if (core == NULL || proc == NULL) {
+        return -1;
+    }
+
+    if (!ISSET(proc->flags, PROC_SLEEPING)) {
+        return -1;
+    }
+
+    proc->flags &= ~PROC_SLEEPING;
+    return 0;
+}
+
+/*
  * MI proc init code
  */
 int
@@ -273,10 +310,21 @@ proc_add_range(struct proc *procp, vaddr_t va, paddr_t pa, size_t len)
 int
 proc_kill(struct proc *procp, int status)
 {
+    struct proc *self = proc_self();
+
     if (procp == NULL) {
         return -EINVAL;
     }
 
+    /*
+     * Try to wake up our parent if they are sleeping
+     * at all.
+     */
+    if (self->pid == procp->pid) {
+        if (self->parent != NULL)
+            proc_wake(self->parent);
+    }
+
     procp->flags |= PROC_EXITING;
     proc_clear_ranges(procp);
     TAILQ_REMOVE(&procq, procp, lup_link);
@@ -337,6 +385,7 @@ proc_spawn(const char *path, struct penv_blk *envbp)
     }
 
     proc->envblk = envbp;
+    proc->parent = proc_self();
     md_set_ip(proc, elf.entrypoint);
     sched_enq(&core->scq, proc);
 
diff --git a/src/sys/os/os_sched.c b/src/sys/os/os_sched.c
index d5824aa..e636f0a 100644
--- a/src/sys/os/os_sched.c
+++ b/src/sys/os/os_sched.c
@@ -111,9 +111,28 @@ sched_deq(struct sched_queue *q, struct proc **procp)
     }
 
     spinlock_acquire(&q->lock);
-    proc = TAILQ_FIRST(&q->q);
-    TAILQ_REMOVE(&q->q, proc, link);
+    if ((proc = TAILQ_FIRST(&q->q)) == NULL) {
+        spinlock_release(&q->lock);
+        return -EAGAIN;
+    }
+
+    /* Find a process that is not sleeping */
+    while (proc != NULL) {
+        if (ISSET(proc->flags, PROC_SLEEPING)) {
+            proc = TAILQ_NEXT(proc, link);
+            continue;
+        }
+
+        break;
+    }
+
+    /* Is there anything? */
+    if (proc == NULL) {
+        spinlock_release(&q->lock);
+        return -EAGAIN;
+    }
 
+    TAILQ_REMOVE(&q->q, proc, link);
     *procp = proc;
     --q->nproc;
     spinlock_release(&q->lock);