check_deref_check.c

   1 /*
   2  * sparse/check_deref_check.c
   3  *
   4  * Copyright (C) 2009 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include "smatch.h"
  11
  12 static int my_id;
  13
  14 STATE(derefed);
  15 STATE(oktocheck);
  16
  17 static void underef(const char *name, struct symbol *sym, struct expression *expr, void *unused)
  18 {
  19         set_state(my_id, name, sym, &oktocheck);
  20 }
  21
  22 static void match_dereference(struct expression *expr)
  23 {
  24         char *name;
  25
  26         if (strcmp(show_special(expr->deref->op), "*"))
  27                 return;
  28         expr = expr->deref->unop;
  29         expr = strip_expr(expr);
  30
  31         set_state_expr(my_id, expr, &derefed);
  32
  33         name = get_variable_from_expr(expr, NULL);
  34         if (!name)
  35                 return;
  36         add_modification_hook(name, &underef, NULL);
  37         free_string(name);
  38 }
  39
  40
  41 static void match_condition(struct expression *expr)
  42 {
  43         if (get_state_expr(my_id, expr) == &derefed) {
  44                 char *name;
  45
  46                 name = get_variable_from_expr(expr, NULL);
  47                 sm_msg("warn: variable derefenced before check '%s'",
  48                         name);
  49                 set_state_expr(my_id, expr, &oktocheck);
  50                 free_string(name);
  51         }
  52 }
  53
  54
  55 void check_deref_check(int id)
  56 {
  57         my_id = id;
  58         set_default_state(my_id, &oktocheck);
  59         add_hook(&match_dereference, DEREF_HOOK);
  60         add_hook(&match_condition, CONDITION_HOOK);
  61 }