ckctype.c revision 1.4 
1/* $NetBSD: ckctype.c,v 1.4 2022/03/19 14:48:31 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 1.4 2022/03/19 14:48:31 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 must not
48 * be called with an argument of type 'char'.  In such a case, the argument
49 * must be converted to 'unsigned char'.  The tricky thing is that even though
50 * the expected argument type is 'int', a 'char' argument must not be directly
51 * cast to 'int', as that would preserve negative argument values.
52 *
53 * See also:
54 *	ctype(3)
55 *	https://stackoverflow.com/a/60696378
56 */
57
58static bool
59is_ctype_function(const char *name)
60{
61
62	if (name[0] == 'i' && name[1] == 's')
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
76	if (name[0] == 't' && name[1] == 'o')
77		return strcmp(name, "tolower") == 0 ||
78		       strcmp(name, "toupper") == 0;
79
80	return false;
81}
82
83static bool
84is_ctype_table(const char *name)
85{
86
87	/* NetBSD sys/ctype_bits.h 1.6 from 2016-01-22 */
88	if (strcmp(name, "_ctype_tab_") == 0 ||
89	    strcmp(name, "_tolower_tab_") == 0 ||
90	    strcmp(name, "_toupper_tab_") == 0)
91		return true;
92
93	/* NetBSD sys/ctype_bits.h 1.1 from 2010-06-01 */
94	return strcmp(name, "_ctype_") == 0;
95}
96
97static void
98check_ctype_arg(const char *func, const tnode_t *arg)
99{
100	const tnode_t *on, *cn;
101
102	for (on = arg; on->tn_op == CVT; on = on->tn_left)
103		if (on->tn_type->t_tspec == UCHAR)
104			return;
105	if (on->tn_type->t_tspec == UCHAR)
106		return;
107
108	if (arg->tn_op == CVT && arg->tn_cast) {
109		/* argument to '%s' must be cast to 'unsigned char', not to '%s' */
110		warning(342, func, type_name(arg->tn_type));
111		return;
112	}
113
114	cn = before_conversion(arg);
115	if (cn->tn_type->t_tspec == CHAR) {
116		/* argument to '%s' must be 'unsigned char' or EOF, not '%s' */
117		warning(341, func, type_name(cn->tn_type));
118		return;
119	}
120}
121
122void
123check_ctype_function_call(const tnode_t *func, const tnode_t *args)
124{
125
126	if (func->tn_op == NAME &&
127	    is_ctype_function(func->tn_sym->s_name) &&
128	    args != NULL &&
129	    args->tn_left != NULL &&
130	    args->tn_right == NULL)
131		check_ctype_arg(func->tn_sym->s_name, args->tn_left);
132}
133
134void
135check_ctype_macro_invocation(const tnode_t *ln, const tnode_t *rn)
136{
137
138	if (ln->tn_op == PLUS &&
139	    ln->tn_left != NULL &&
140	    ln->tn_left->tn_op == LOAD &&
141	    ln->tn_left->tn_left != NULL &&
142	    ln->tn_left->tn_left->tn_op == NAME &&
143	    is_ctype_table(ln->tn_left->tn_left->tn_sym->s_name))
144		check_ctype_arg("function from <ctype.h>", rn);
145}
146