ckctype.c revision 1.3 
1/* $NetBSD: ckctype.c,v 1.3 2021/07/25 22:43:08 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 1.3 2021/07/25 22:43:08 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		return strcmp(name, "isalnum") == 0 ||
61		       strcmp(name, "isalpha") == 0 ||
62		       strcmp(name, "isblank") == 0 ||
63		       strcmp(name, "iscntrl") == 0 ||
64		       strcmp(name, "isdigit") == 0 ||
65		       strcmp(name, "isgraph") == 0 ||
66		       strcmp(name, "islower") == 0 ||
67		       strcmp(name, "isprint") == 0 ||
68		       strcmp(name, "ispunct") == 0 ||
69		       strcmp(name, "isspace") == 0 ||
70		       strcmp(name, "isupper") == 0 ||
71		       strcmp(name, "isxdigit") == 0;
72
73	if (name[0] == 't' && name[1] == 'o')
74		return strcmp(name, "tolower") == 0 ||
75		       strcmp(name, "toupper") == 0;
76
77	return false;
78}
79
80static bool
81is_ctype_table(const char *name)
82{
83
84	/* NetBSD sys/ctype_bits.h 1.6 from 2016-01-22 */
85	if (strcmp(name, "_ctype_tab_") == 0 ||
86	    strcmp(name, "_tolower_tab_") == 0 ||
87	    strcmp(name, "_toupper_tab_") == 0)
88		return true;
89
90	/* NetBSD sys/ctype_bits.h 1.1 from 2010-06-01 */
91	return strcmp(name, "_ctype_") == 0;
92}
93
94static void
95check_ctype_arg(const char *func, const tnode_t *arg)
96{
97	const tnode_t *on, *cn;
98
99	for (on = arg; on->tn_op == CVT; on = on->tn_left)
100		if (on->tn_type->t_tspec == UCHAR)
101			return;
102	if (on->tn_type->t_tspec == UCHAR)
103		return;
104
105	if (arg->tn_op == CVT && arg->tn_cast) {
106		/* argument to '%s' must be cast to 'unsigned char', not to '%s' */
107		warning(342, func, type_name(arg->tn_type));
108		return;
109	}
110
111	cn = before_conversion(arg);
112	if (cn->tn_type->t_tspec == CHAR) {
113		/* argument to '%s' must be 'unsigned char' or EOF, not '%s' */
114		warning(341, func, type_name(cn->tn_type));
115		return;
116	}
117}
118
119void
120check_ctype_function_call(const tnode_t *func, const tnode_t *args)
121{
122
123	if (func->tn_op == NAME &&
124	    is_ctype_function(func->tn_sym->s_name) &&
125	    args != NULL &&
126	    args->tn_left != NULL &&
127	    args->tn_right == NULL)
128		check_ctype_arg(func->tn_sym->s_name, args->tn_left);
129}
130
131void
132check_ctype_macro_invocation(const tnode_t *ln, const tnode_t *rn)
133{
134
135	if (ln->tn_op == PLUS &&
136	    ln->tn_left != NULL &&
137	    ln->tn_left->tn_op == LOAD &&
138	    ln->tn_left->tn_left != NULL &&
139	    ln->tn_left->tn_left->tn_op == NAME &&
140	    is_ctype_table(ln->tn_left->tn_left->tn_sym->s_name))
141		check_ctype_arg("function from <ctype.h>", rn);
142}
143