ckctype.c revision 1.1 
1/* $NetBSD: ckctype.c,v 1.1 2021/04/05 02:07:14 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
34#include "nbtool_config.h"
35
36#endif
37
38#include <sys/cdefs.h>
39
40#if defined(__RCSID) && !defined(lint)
41__RCSID("$NetBSD: ckctype.c,v 1.1 2021/04/05 02:07:14 rillig Exp $");
42#endif
43
44#include <string.h>
45
46#include "lint1.h"
47
48/*
49 * Check that the functions from <ctype.h> are used properly.  They are
50 * difficult to use when their argument comes from an expression of type
51 * 'char'.  In such a case, the argument must be converted to 'unsigned char',
52 * not directly to 'int'.
53 *
54 * https://stackoverflow.com/a/60696378
55 */
56
57#define NEED(cond) \
58	do {			\
59		if (!(cond))	\
60			return;	\
61	} while (false)
62
63static bool
64is_ctype_function(const char *name)
65{
66
67	if (name[0] != 'i' || name[1] != 's')
68		if (name[0] != 't' || name[1] != 'o')
69			return false;
70
71	return strcmp(name, "isalnum") == 0 ||
72	       strcmp(name, "isalpha") == 0 ||
73	       strcmp(name, "isblank") == 0 ||
74	       strcmp(name, "iscntrl") == 0 ||
75	       strcmp(name, "isdigit") == 0 ||
76	       strcmp(name, "isgraph") == 0 ||
77	       strcmp(name, "islower") == 0 ||
78	       strcmp(name, "isprint") == 0 ||
79	       strcmp(name, "ispunct") == 0 ||
80	       strcmp(name, "isspace") == 0 ||
81	       strcmp(name, "isupper") == 0 ||
82	       strcmp(name, "isxdigit") == 0 ||
83	       strcmp(name, "tolower") == 0 ||
84	       strcmp(name, "toupper") == 0;
85}
86
87static bool
88is_ctype_table(const char *name)
89{
90
91	/* NetBSD sys/ctype_bits.h 1.6 from 2016-01-22 */
92	if (strcmp(name, "_ctype_tab_") == 0 ||
93	    strcmp(name, "_tolower_tab_") == 0 ||
94	    strcmp(name, "_toupper_tab_") == 0)
95		return true;
96
97	/* NetBSD sys/ctype_bits.h 1.1 from 2010-06-01 */
98	return strcmp(name, "_ctype_") == 0;
99}
100
101static void
102check_ctype_arg(const char *func, const tnode_t *arg)
103{
104	const tnode_t *on, *cn;
105
106	for (on = arg; on->tn_op == CVT; on = on->tn_left)
107		if (on->tn_type->t_tspec == UCHAR)
108			return;
109	if (on->tn_type->t_tspec == UCHAR)
110		return;
111
112	if (arg->tn_op == CVT && arg->tn_cast) {
113		/* argument to '%s' must be cast to 'unsigned char', not to '%s' */
114		warning(342, func, type_name(arg->tn_type));
115		return;
116	}
117
118	cn = before_conversion(arg);
119	if (cn->tn_type->t_tspec == CHAR) {
120		/* argument to '%s' must be 'unsigned char' or EOF, not '%s' */
121		warning(341, func, type_name(cn->tn_type));
122		return;
123	}
124}
125
126void
127check_ctype_function_call(const tnode_t *func, const tnode_t *args)
128{
129
130	NEED(func->tn_op == NAME);
131	NEED(is_ctype_function(func->tn_sym->s_name));
132	NEED(args != NULL);
133	NEED(args->tn_left != NULL);
134	NEED(args->tn_right == NULL);
135
136	check_ctype_arg(func->tn_sym->s_name, args->tn_left);
137}
138
139void
140check_ctype_macro_invocation(const tnode_t *ln, const tnode_t *rn)
141{
142
143	NEED(ln->tn_op == PLUS);
144	NEED(ln->tn_left != NULL);
145	NEED(ln->tn_left->tn_op == LOAD);
146	NEED(ln->tn_left->tn_left != NULL);
147	NEED(ln->tn_left->tn_left->tn_op == NAME);
148	NEED(is_ctype_table(ln->tn_left->tn_left->tn_sym->s_name));
149
150	check_ctype_arg("function from <ctype.h>", rn);
151}
152