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(struct sm_state *sm)
  19 {
  20         if (sm->state == &derefed)
  21                 set_state(my_id, sm->name, sm->sym, &oktocheck);
  22 }
  23
  24 static void match_dereference(struct expression *expr)
  25 {
  26         char *name;
  27
  28         if (expr->type != EXPR_PREOP)
  29                 return;
  30         if (getting_address())
  31                 return;
  32         expr = strip_expr(expr->unop);
  33         if (implied_not_equal(expr, 0))
  34                 return;
  35
  36         set_state_expr(my_id, expr, &derefed);
  37         name = get_variable_from_expr(expr, NULL);
  38         if (!name)
  39                 return;
  40         free_string(name);
  41 }
  42
  43 static void set_param_dereferenced(struct expression *arg, char *unused)
  44 {
  45         if (implied_not_equal(arg, 0))
  46                 return;
  47         set_state_expr(my_id, arg, &derefed);
  48 }
  49
  50 static void match_condition(struct expression *expr)
  51 {
  52         struct sm_state *sm;
  53
  54         if (__in_pre_condition)
  55                 return;
  56
  57         if (get_macro_name(expr->pos))
  58                 return;
  59
  60         sm = get_sm_state_expr(my_id, expr);
  61         if (!sm || sm->state != &derefed)
  62                 return;
  63
  64         sm_msg("warn: variable dereferenced before check '%s' (see line %d)", sm->name, sm->line);
  65         set_state_expr(my_id, expr, &oktocheck);
  66 }
  67
  68 void check_deref_check(int id)
  69 {
  70         my_id = id;
  71         add_hook(&match_dereference, DEREF_HOOK);
  72         add_hook(&match_condition, CONDITION_HOOK);
  73         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
  74         add_modification_hook(my_id, &underef);
  75 }