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 #include "smatch_extra.h"
  12
  13 static int my_id;
  14
  15 STATE(derefed);
  16 STATE(oktocheck);
  17
  18 static void underef(const char *name, struct symbol *sym, struct expression *expr, void *unused)
  19 {
  20         set_state(my_id, name, sym, &oktocheck);
  21 }
  22
  23 static void match_dereference(struct expression *expr)
  24 {
  25         char *name;
  26
  27         if (expr->type != EXPR_PREOP)
  28                 return;
  29         expr = strip_expr(expr->unop);
  30         if (implied_not_equal(expr, 0))
  31                 return;
  32
  33         set_state_expr(my_id, expr, &derefed);
  34
  35         name = get_variable_from_expr(expr, NULL);
  36         if (!name)
  37                 return;
  38         add_modification_hook(name, &underef, NULL);
  39         free_string(name);
  40 }
  41
  42 static void match_condition(struct expression *expr)
  43 {
  44         if (get_state_expr(my_id, expr) == &derefed) {
  45                 char *name;
  46
  47                 name = get_variable_from_expr(expr, NULL);
  48                 if (!implied_not_equal(expr, 0))
  49                         sm_msg("warn: variable derefenced before check '%s'", name);
  50                 set_state_expr(my_id, expr, &oktocheck);
  51                 free_string(name);
  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 }