updates

src/userprog/process.c

@@ -139,17 +139,16 @@ release_child (struct wait_status *cs)
 int
 process_wait (tid_t child_tid) 
 {
-  while(1){}
   struct list_elem * e;
-  struct thread * t = NULL;
+  struct wait_status * t = NULL;
   struct thread * cur = thread_current();
   for (e = list_begin (&cur->children); e != list_end (&cur->children);e = list_next (e)){
-      struct thread * t2 = list_entry (e, struct thread, allelem);
+      struct wait_status * t2 = list_entry (e, struct wait_status, elem);
       if (t2->tid == child_tid){t = t2; break;}
   }
   if (t == NULL){return -1;}
-  sema_down(&(t->wait_status->dead));
-  return -1;
+  sema_down(&(t->dead));
+  return t->exit_code;
 }
 
 /* Free the current process's resources. */

src/userprog/syscall.c

@@ -186,9 +186,8 @@ sys_halt (void)
 static int
 sys_exit (int exit_code) 
 {
-  struct thread *t = thread_current();
-  t->wait_status->exit_code = exit_code;
-  //printf("%s: exit(%d)\n", t->name, exit_code);
+  thread_current ()->wait_status->exit_code = exit_code;
+  sema_up(&(thread_current ()->wait_status->dead));
   thread_exit ();
   NOT_REACHED ();
 }
@@ -197,16 +196,16 @@ sys_exit (int exit_code)
 static int
 sys_exec (const char *ufile) 
 {
-/* Add code */
-  thread_exit ();
+	char *kfile = copy_in_string(ufile);
+	return process_execute(kfile);
 }
 
 /* Wait system call. */
 static int
 sys_wait (tid_t child) 
 {
-  process_wait(child);
   //thread_exit ();
+  return process_wait(child);
 }
 
 /* Create system call. */