1 /*
2 * Copyright (C) 2010 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
match_free(const char * fn,struct expression * expr,void * data)22 static void match_free(const char *fn, struct expression *expr, void *data)
23 {
24 struct expression *arg_expr;
25 char *name;
26 sval_t sval;
27
28 arg_expr = get_argument_from_call_expr(expr->args, 0);
29 if (!get_implied_value(arg_expr, &sval))
30 return;
31 if (sval.value != 0)
32 return;
33 name = expr_to_var(arg_expr);
34 sm_warning("calling %s() when '%s' is always NULL.", fn, name);
35 free_string(name);
36 }
37
check_freeing_null(int id)38 void check_freeing_null(int id)
39 {
40 my_id = id;
41 if (!option_spammy)
42 return;
43 if (option_project == PROJ_KERNEL)
44 add_function_hook("kfree", &match_free, NULL);
45 else
46 add_function_hook("free", &match_free, NULL);
47 }
48