pre-empt both user and kernel, in clock interrupt

usertest.c tests pre-emption
kill()

1 files changed, 22 insertions, 26 deletions

diff --git a/syscall.c b/syscall.c
index 03fe608..4ecb31c 100644
--- a/syscall.c
+++ b/syscall.c
@@ -155,32 +155,7 @@ sys_fork()
 int
 sys_exit()
 {
-  struct proc *p;
-  struct proc *cp = curproc[cpu()];
-  int fd;
-
-  for(fd = 0; fd < NOFILE; fd++){
-    if(cp->fds[fd]){
-      fd_close(cp->fds[fd]);
-      cp->fds[fd] = 0;
-    }
-  }
-
-  cp->state = ZOMBIE;
-
-  // wake up parent
-  for(p = proc; p < &proc[NPROC]; p++)
-    if(p->pid == cp->ppid)
-      wakeup(p);
-
-  // abandon children
-  for(p = proc; p < &proc[NPROC]; p++)
-    if(p->ppid == cp->pid)
-      p->pid = 1;
-
-  // switch into scheduler
-  swtch();
-
+  proc_exit();
   return 0;
 }
 
@@ -250,6 +225,24 @@ sys_block(void)
   return 0;
 }
 
+int
+sys_kill()
+{
+  int pid;
+  struct proc *p;
+
+  fetcharg(0, &pid);
+  for(p = proc; p < &proc[NPROC]; p++){
+    if(p->pid == pid && p->state != UNUSED){
+      p->killed = 1;
+      if(p->state == WAITING)
+        p->state = RUNNABLE;
+      return 0;
+    }
+  }
+  return -1;
+}
+
 void
 syscall()
 {
@@ -286,6 +279,9 @@ syscall()
   case SYS_block:
     ret = sys_block();
     break;
+  case SYS_kill:
+    ret = sys_kill();
+    break;
   default:
     cprintf("unknown sys call %d\n", num);
     // XXX fault