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                 expr = strip_expr(expr->unop);
  29         } else {
  30                 if (expr->deref->op != '*')
  31                         return;
  32                 expr = expr->deref->unop;
  33                 expr = strip_expr(expr);
  34         }
  35         if (implied_not_equal(expr, 0))
  36                 return;
  37
  38         set_state_expr(my_id, expr, &derefed);
  39
  40         name = get_variable_from_expr(expr, NULL);
  41         if (!name)
  42                 return;
  43         add_modification_hook(name, &underef, NULL);
  44         free_string(name);
  45 }
  46
  47 static void match_condition(struct expression *expr)
  48 {
  49         if (get_state_expr(my_id, expr) == &derefed) {
  50                 char *name;
  51
  52                 name = get_variable_from_expr(expr, NULL);
  53                 if (!implied_not_equal(expr, 0))
  54                         sm_msg("warn: variable derefenced before check '%s'", name);
  55                 set_state_expr(my_id, expr, &oktocheck);
  56                 free_string(name);
  57         }
  58 }
  59
  60 void check_deref_check(int id)
  61 {
  62         my_id = id;
  63         set_default_state(my_id, &oktocheck);
  64         add_hook(&match_dereference, DEREF_HOOK);
  65         add_hook(&match_condition, CONDITION_HOOK);
  66 }