check_memset.c

   1 /*
   2  * Copyright (C) 2011 Dan Carpenter.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  16  */
  17
  18 #include "smatch.h"
  19
  20 static int my_id;
  21
  22 static void check_size_not_zero(struct expression *expr)
  23 {
  24         sval_t sval;
  25
  26         if (expr->type != EXPR_VALUE)
  27                 return;
  28         if (!get_value(expr, &sval))
  29                 return;
  30         if (sval.value != 0)
  31                 return;
  32         sm_error("calling memset(x, y, 0);");
  33 }
  34
  35 static void check_size_not_ARRAY_SIZE(struct expression *expr)
  36 {
  37         char *name;
  38
  39         name = get_macro_name(expr->pos);
  40         if (name && strcmp(name, "ARRAY_SIZE") == 0)
  41                 sm_warning("calling memset(x, y, ARRAY_SIZE());");
  42 }
  43
  44 static void match_memset(const char *fn, struct expression *expr, void *data)
  45 {
  46         struct expression *arg_expr;
  47
  48         arg_expr = get_argument_from_call_expr(expr->args, 2);
  49         if (!arg_expr)
  50                 return;
  51         check_size_not_zero(arg_expr);
  52         check_size_not_ARRAY_SIZE(arg_expr);
  53 }
  54
  55 void check_memset(int id)
  56 {
  57         my_id = id;
  58         add_function_hook("memset", &match_memset, NULL);
  59         add_function_hook("__builtin_memset", &match_memset, NULL);
  60 }