check_container_of.c

   1 /*
   2  * Copyright (C) 2010 Dan Carpenter.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  16  */
  17
  18 /*
  19  * Some macros don't return NULL pointers.  Complain if people
  20  * check the results for NULL because obviously the programmers
  21  * don't know what the pants they're doing.
  22  */
  23
  24 #include "smatch.h"
  25
  26 static int my_id;
  27
  28 STATE(non_null);
  29
  30 static void is_ok(struct sm_state *sm, struct expression *mod_expr)
  31 {
  32         set_state(my_id, sm->name, sm->sym, &undefined);
  33 }
  34
  35 static void match_non_null(const char *fn, struct expression *expr, void *unused)
  36 {
  37         set_state_expr(my_id, expr->left, &non_null);
  38 }
  39
  40 static void match_condition(struct expression *expr)
  41 {
  42         if (__in_pre_condition)
  43                 return;
  44
  45         if (get_macro_name(expr->pos))
  46                 return;
  47
  48         if (get_state_expr(my_id, expr) == &non_null) {
  49                 char *name;
  50
  51                 name = expr_to_var(expr);
  52                 sm_warning("can '%s' even be NULL?", name);
  53                 set_state_expr(my_id, expr, &undefined);
  54                 free_string(name);
  55         }
  56 }
  57
  58 void check_container_of(int id)
  59 {
  60         if (option_project != PROJ_KERNEL)
  61                 return;
  62
  63         my_id = id;
  64         add_macro_assign_hook("container_of", &match_non_null, NULL);
  65         add_macro_assign_hook("list_first_entry", &match_non_null, NULL);
  66         add_function_assign_hook("nla_data", &match_non_null, NULL);
  67         add_modification_hook(my_id, &is_ok);
  68         add_hook(&match_condition, CONDITION_HOOK);
  69 }