check_container_of.c

   1 /*
   2  * smatch/check_container_of.c
   3  *
   4  * Copyright (C) 2010 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9 /*
  10  * Some macros don't return NULL pointers.  Complain if people
  11  * check the results for NULL because obviously the programmers
  12  * don't know what the pants they're doing.
  13  */
  14
  15 #include "smatch.h"
  16
  17 static int my_id;
  18
  19 STATE(non_null);
  20
  21 static void is_ok(const char *name, struct symbol *sym, struct expression *expr, void *unused)
  22 {
  23         set_state(my_id, name, sym, &undefined);
  24 }
  25
  26 static void match_non_null(const char *fn, struct expression *expr, void *unused)
  27 {
  28         set_state_expr(my_id, expr->left, &non_null);
  29 }
  30
  31 static void match_condition(struct expression *expr)
  32 {
  33         if (__in_pre_condition)
  34                 return;
  35
  36         if (get_macro_name(&expr->pos))
  37                 return;
  38
  39         if (get_state_expr(my_id, expr) == &non_null) {
  40                 char *name;
  41
  42                 name = get_variable_from_expr(expr, NULL);
  43                 sm_msg("warn: can '%s' even be NULL?", name);
  44                 set_state_expr(my_id, expr, &undefined);
  45                 free_string(name);
  46         }
  47 }
  48
  49 void check_container_of(int id)
  50 {
  51         if (option_project != PROJ_KERNEL)
  52                 return;
  53
  54         my_id = id;
  55         add_macro_assign_hook("container_of", &match_non_null, NULL);
  56         add_macro_assign_hook("list_first_entry", &match_non_null, NULL);
  57         set_default_modification_hook(my_id, &is_ok);
  58         add_hook(&match_condition, CONDITION_HOOK);
  59 }