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      1 /* $NetBSD: ckctype.c,v 1.13 2024/12/18 18:14:54 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 (at) 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)
     39 __RCSID("$NetBSD: ckctype.c,v 1.13 2024/12/18 18:14:54 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 parameter type is declared as 'int', a 'char' argument must not be
     51  * directly 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 
     58 static bool
     59 is_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 
     83 static bool
     84 is_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 
     97 static void
     98 check_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->u.ops.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 ... */
    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 != UCHAR && cn->tn_type->t_tspec != INT) {
    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 
    122 void
    123 check_ctype_function_call(const function_call *call)
    124 {
    125 
    126 	if (call->args_len == 1 &&
    127 	    call->func->tn_op == NAME &&
    128 	    is_ctype_function(call->func->u.sym->s_name))
    129 		check_ctype_arg(call->func->u.sym->s_name, call->args[0]);
    130 }
    131 
    132 void
    133 check_ctype_macro_invocation(const tnode_t *ln, const tnode_t *rn)
    134 {
    135 
    136 	if (ln->tn_op == PLUS &&
    137 	    ln->u.ops.left != NULL &&
    138 	    ln->u.ops.left->tn_op == LOAD &&
    139 	    ln->u.ops.left->u.ops.left != NULL &&
    140 	    ln->u.ops.left->u.ops.left->tn_op == NAME &&
    141 	    is_ctype_table(ln->u.ops.left->u.ops.left->u.sym->s_name))
    142 		check_ctype_arg("function from <ctype.h>", rn);
    143 }
    144