ckctype.c revision 1.2 
1/* $NetBSD: ckctype.c,v 1.2 2021/04/05 02:17:52 rillig Exp $ */
2
3/*-
4 * Copyright (c) 2021 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Roland Illig <rillig@NetBSD.org>.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#if HAVE_NBTOOL_CONFIG_H
33#include "nbtool_config.h"
34#endif
35
36#include <sys/cdefs.h>
37
38#if defined(__RCSID) && !defined(lint)
39__RCSID("$NetBSD: ckctype.c,v 1.2 2021/04/05 02:17:52 rillig Exp $");
40#endif
41
42#include <string.h>
43
44#include "lint1.h"
45
46/*
47 * Check that the functions from <ctype.h> are used properly.  They are
48 * difficult to use when their argument comes from an expression of type
49 * 'char'.  In such a case, the argument must be converted to 'unsigned char',
50 * not directly to 'int'.
51 *
52 * https://stackoverflow.com/a/60696378
53 */
54
55static bool
56is_ctype_function(const char *name)
57{
58
59	if (name[0] != 'i' || name[1] != 's')
60		if (name[0] != 't' || name[1] != 'o')
61			return false;
62
63	return strcmp(name, "isalnum") == 0 ||
64	       strcmp(name, "isalpha") == 0 ||
65	       strcmp(name, "isblank") == 0 ||
66	       strcmp(name, "iscntrl") == 0 ||
67	       strcmp(name, "isdigit") == 0 ||
68	       strcmp(name, "isgraph") == 0 ||
69	       strcmp(name, "islower") == 0 ||
70	       strcmp(name, "isprint") == 0 ||
71	       strcmp(name, "ispunct") == 0 ||
72	       strcmp(name, "isspace") == 0 ||
73	       strcmp(name, "isupper") == 0 ||
74	       strcmp(name, "isxdigit") == 0 ||
75	       strcmp(name, "tolower") == 0 ||
76	       strcmp(name, "toupper") == 0;
77}
78
79static bool
80is_ctype_table(const char *name)
81{
82
83	/* NetBSD sys/ctype_bits.h 1.6 from 2016-01-22 */
84	if (strcmp(name, "_ctype_tab_") == 0 ||
85	    strcmp(name, "_tolower_tab_") == 0 ||
86	    strcmp(name, "_toupper_tab_") == 0)
87		return true;
88
89	/* NetBSD sys/ctype_bits.h 1.1 from 2010-06-01 */
90	return strcmp(name, "_ctype_") == 0;
91}
92
93static void
94check_ctype_arg(const char *func, const tnode_t *arg)
95{
96	const tnode_t *on, *cn;
97
98	for (on = arg; on->tn_op == CVT; on = on->tn_left)
99		if (on->tn_type->t_tspec == UCHAR)
100			return;
101	if (on->tn_type->t_tspec == UCHAR)
102		return;
103
104	if (arg->tn_op == CVT && arg->tn_cast) {
105		/* argument to '%s' must be cast to 'unsigned char', not to '%s' */
106		warning(342, func, type_name(arg->tn_type));
107		return;
108	}
109
110	cn = before_conversion(arg);
111	if (cn->tn_type->t_tspec == CHAR) {
112		/* argument to '%s' must be 'unsigned char' or EOF, not '%s' */
113		warning(341, func, type_name(cn->tn_type));
114		return;
115	}
116}
117
118void
119check_ctype_function_call(const tnode_t *func, const tnode_t *args)
120{
121
122	if (func->tn_op == NAME &&
123	    is_ctype_function(func->tn_sym->s_name) &&
124	    args != NULL &&
125	    args->tn_left != NULL &&
126	    args->tn_right == NULL)
127		check_ctype_arg(func->tn_sym->s_name, args->tn_left);
128}
129
130void
131check_ctype_macro_invocation(const tnode_t *ln, const tnode_t *rn)
132{
133
134	if (ln->tn_op == PLUS &&
135	    ln->tn_left != NULL &&
136	    ln->tn_left->tn_op == LOAD &&
137	    ln->tn_left->tn_left != NULL &&
138	    ln->tn_left->tn_left->tn_op == NAME &&
139	    is_ctype_table(ln->tn_left->tn_left->tn_sym->s_name))
140		check_ctype_arg("function from <ctype.h>", rn);
141}
142