check_type.c

   1 /*
   2  * Copyright (C) 2009 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 int in_function(const char *fn)
  23 {
  24         char *cur_func = get_function();
  25
  26         if (!cur_func)
  27                 return 0;
  28         if (!strcmp(cur_func, fn))
  29                 return 1;
  30         return 0;
  31 }
  32
  33 static void match_free(const char *fn, struct expression *expr, void *data)
  34 {
  35         struct expression *arg_expr;
  36         char *name;
  37         struct symbol *type;
  38
  39         arg_expr = get_argument_from_call_expr(expr->args, 0);
  40         type = get_pointer_type(arg_expr);
  41         if (!type || !type->ident)
  42                 return;
  43
  44         name = expr_to_str(arg_expr);
  45
  46         if (!strcmp("sk_buff", type->ident->name)) {
  47                 sm_error("use kfree_skb() here instead of kfree(%s)", name);
  48         } else if (!strcmp("net_device", type->ident->name)) {
  49                 if (in_function("alloc_netdev"))
  50                         return;
  51                 if (in_function("alloc_netdev_mqs"))
  52                         return;
  53                 sm_error("use free_netdev() here instead of kfree(%s)", name);
  54         }
  55
  56         free_string(name);
  57 }
  58
  59 void check_type(int id)
  60 {
  61         my_id = id;
  62         if (option_project == PROJ_KERNEL)
  63                 add_function_hook("kfree", &match_free, NULL);
  64 }