1/*
2 * Copyright (C) 2013 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#include "scope.h"
19#include "smatch.h"
20#include "smatch_extra.h"
21
22static int match_strlen(struct expression *call, void *unused, struct range_list **rl)
23{
24	struct expression *str;
25	unsigned long max;
26
27	str = get_argument_from_call_expr(call->args, 0);
28	if (get_implied_strlen(str, rl) && sval_is_positive(rl_min(*rl))) {
29		*rl = cast_rl(&ulong_ctype, *rl);
30		return 1;
31	}
32	/* smatch_strlen.c is not very complete */
33	max = get_array_size_bytes_max(str);
34	if (max == 0) {
35		*rl = alloc_rl(sval_type_val(&ulong_ctype, 0),
36			       sval_type_val(&ulong_ctype, STRLEN_MAX_RET));
37	} else {
38		max--;
39		*rl = alloc_rl(sval_type_val(&ulong_ctype, 0),
40			       sval_type_val(&ulong_ctype, max));
41	}
42	return 1;
43}
44
45static int match_strnlen(struct expression *call, void *unused, struct range_list **rl)
46{
47	struct expression *limit;
48	sval_t fixed;
49	sval_t bound;
50	sval_t ulong_max = sval_type_val(&ulong_ctype, ULONG_MAX);
51
52	match_strlen(call, NULL, rl);
53	limit = get_argument_from_call_expr(call->args, 1);
54	if (!get_implied_max(limit, &bound))
55		return 1;
56	if (sval_cmp(bound, ulong_max) == 0)
57		return 1;
58	if (rl_to_sval(*rl, &fixed) && sval_cmp(fixed, bound) >= 0) {
59		*rl = alloc_rl(bound, bound);
60		return 1;
61	}
62
63	bound.value++;
64	*rl = remove_range(*rl, bound, ulong_max);
65
66	return 1;
67}
68
69static int match_sprintf(struct expression *call, void *_arg, struct range_list **rl)
70{
71	int str_arg = PTR_INT(_arg);
72	int min, max;
73
74	min = get_formatted_string_min_size(call, str_arg);
75	max = get_formatted_string_size(call, str_arg);
76	if (min < 0 || max < 0) {
77		*rl = alloc_whole_rl(&ulong_ctype);
78	} else {
79		*rl = alloc_rl(ll_to_sval(min), ll_to_sval(max));
80		*rl = cast_rl(get_type(call), *rl);
81	}
82	return 1;
83}
84
85void register_common_functions(int id)
86{
87	/*
88	 * When you add a new function here, then don't forget to delete it from
89	 * the database and smatch_data/.
90	 */
91	add_implied_return_hook("strlen", &match_strlen, NULL);
92	add_implied_return_hook("strnlen", &match_strnlen, NULL);
93	add_implied_return_hook("sprintf", &match_sprintf, INT_PTR(1));
94	add_implied_return_hook("snprintf", &match_sprintf, INT_PTR(2));
95}
96