1/*
2 * Copyright (C) 2014 Oracle.
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/*
19 * This file is sort of like check_dereferences_param.c.  In theory the one
20 * difference should be that the param is NULL it should still be counted as a
21 * free.  But for now I don't handle that case.
22 */
23
24#include "smatch.h"
25#include "smatch_extra.h"
26#include "smatch_slist.h"
27
28static int my_id;
29
30STATE(freed);
31STATE(ignore);
32
33static void set_ignore(struct sm_state *sm, struct expression *mod_expr)
34{
35	set_state(my_id, sm->name, sm->sym, &ignore);
36}
37
38static void freed_variable(struct expression *expr)
39{
40	struct sm_state *sm;
41
42	expr = strip_expr(expr);
43	if (get_param_num(expr) < 0)
44		return;
45
46	sm = get_sm_state_expr(my_id, expr);
47	if (sm && slist_has_state(sm->possible, &ignore))
48		return;
49	set_state_expr(my_id, expr, &freed);
50}
51
52static void match_free(const char *fn, struct expression *expr, void *param)
53{
54	struct expression *arg;
55
56	arg = get_argument_from_call_expr(expr->args, PTR_INT(param));
57	if (!arg)
58		return;
59	freed_variable(arg);
60}
61
62static void set_param_freed(struct expression *call, struct expression *arg, char *key, char *unused)
63{
64	/* XXX FIXME: return_implies has been updated with more information */
65	if (strcmp(key, "$") != 0)
66		return;
67	freed_variable(arg);
68}
69
70static void process_states(void)
71{
72	struct sm_state *sm;
73	int param;
74	const char *param_name;
75
76	FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
77		if (sm->state != &freed)
78			continue;
79		param = get_param_num_from_sym(sm->sym);
80		if (param < 0)
81			continue;
82		param_name = get_param_name(sm);
83		if (!param_name)
84			continue;
85		sql_insert_return_implies(PARAM_FREED, param, param_name, "1");
86	} END_FOR_EACH_SM(sm);
87
88}
89
90void check_frees_param(int id)
91{
92	my_id = id;
93
94	if (option_project == PROJ_KERNEL) {
95		/* The kernel uses check_frees_param_strict.c */
96		return;
97	}
98
99	add_function_hook("free", &match_free, INT_PTR(0));
100
101	select_return_implies_hook(PARAM_FREED, &set_param_freed);
102	add_modification_hook(my_id, &set_ignore);
103
104	all_return_states_hook(&process_states);
105}
106