Fix stack initialization to pass stack addreses (rather than thread addresses) for the arguments and only pass name a single time

src/userprog/process.c

@@ -84,6 +84,10 @@ start_process (void *file_name_)
   char file_name[15];
   strlcpy (file_name, arg, 15);
 
+  /* TODO: Move naming of thread to process_execute, so start
+    tokenizing there. */
+  strlcpy (thread_current ()->name, file_name, 15);
+
   /* Initialize interrupt frame and load executable. */
   memset (&if_, 0, sizeof if_);
   if_.gs = if_.fs = if_.es = if_.ds = if_.ss = SEL_UDSEG;
@@ -95,10 +99,6 @@ start_process (void *file_name_)
      This can't cause overflow due to enforcing that the size of
      command line input must fit in a page. Also keep track
      of pointers to the argument data within a linked list. */
-  char *file_name_ptr = push_to_stack (&if_.esp, file_name,
-                                       (strlen (file_name) + 1)
-                                        * sizeof (char));
-
   struct list arg_list;
   list_init (&arg_list);
 
@@ -117,7 +117,7 @@ start_process (void *file_name_)
           thread_exit ();
         }
 
-      arg_elem->arg = arg;
+      arg_elem->arg = if_.esp;
       list_push_front (&arg_list, &arg_elem->elem);
 
       arg_count++;
@@ -148,6 +148,9 @@ start_process (void *file_name_)
   /* Push a null pointer sentinel inside argv. */
   if_.esp -= sizeof (char *);
   *(char *) if_.esp = NULL;
+  
+  /* Push pointer to the process file name to the stack. */
+  char **argv;
 
   /* Push pointers to process arguments from argument linked list */
   struct list_elem *e = list_begin (&arg_list);
@@ -156,16 +159,12 @@ start_process (void *file_name_)
     {
       struct arg_elem *arg_elem = list_entry (e, struct arg_elem, elem);
       
-      push_to_stack (&if_.esp, &arg_elem->arg, sizeof (arg_elem->arg));
+      argv = push_to_stack (&if_.esp, &arg_elem->arg, sizeof (arg_elem->arg));
       
       e = list_next (e);
       free (arg_elem);
     }
 
-  /* Push pointer to the process file name to the stack. */
-  char **argv = push_to_stack (&if_.esp, &file_name_ptr,
-                               sizeof (file_name_ptr));
-
   /* Push pointer to the start of argv array. */
   push_to_stack (&if_.esp, &argv, sizeof(argv));