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 (expr->type == EXPR_PREOP) {
  27                 expr = strip_expr(expr->unop);
  28         } else {
  29                 if (strcmp(show_special(expr->deref->op), "*"))
  30                         return;
  31                 expr = expr->deref->unop;
  32                 expr = strip_expr(expr);
  33         }
  34
  35         set_state_expr(my_id, expr, &derefed);
  36
  37         name = get_variable_from_expr(expr, NULL);
  38         if (!name)
  39                 return;
  40         add_modification_hook(name, &underef, NULL);
  41         free_string(name);
  42 }
  43
  44
  45 static void match_condition(struct expression *expr)
  46 {
  47         if (get_state_expr(my_id, expr) == &derefed) {
  48                 char *name;
  49
  50                 name = get_variable_from_expr(expr, NULL);
  51                 sm_msg("warn: variable derefenced before check '%s'",
  52                         name);
  53                 set_state_expr(my_id, expr, &oktocheck);
  54                 free_string(name);
  55         }
  56 }
  57
  58
  59 void check_deref_check(int id)
  60 {
  61         my_id = id;
  62         set_default_state(my_id, &oktocheck);
  63         add_hook(&match_dereference, DEREF_HOOK);
  64         add_hook(&match_condition, CONDITION_HOOK);
  65 }