xref: /illumos-gate/usr/src/lib/libc/port/locale/wcsftime.c (revision 4f2483e5d0c339c7ac30db66a67c108da0b33ca6)
1 /*
2  * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
3  * Copyright (c) 2002 Tim J. Robbins
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 /*
29  * Copyright 2025 Bill Sommerfeld
30  */
31 
32 #include "lint.h"
33 #include "mse_int.h"
34 #include <xlocale.h>
35 #include <errno.h>
36 #include <limits.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <time.h>
40 #include <wchar.h>
41 #include <alloca.h>
42 
43 /*
44  * Convert date and time to a wide-character string.
45  *
46  * This is the wide-character counterpart of strftime(). So that we do not
47  * have to duplicate the code of strftime(), we convert the format string to
48  * multibyte, call strftime(), then convert the result back into wide
49  * characters.
50  *
51  * This technique loses in the presence of stateful multibyte encoding if any
52  * of the conversions in the format string change conversion state. When
53  * stateful encoding is implemented, we will need to reset the state between
54  * format specifications in the format string.
55  *
56  * Note carefully that prior to xpg5, the format was char *, not wchar_t.
57  */
58 
59 /*
60  * Hmmm this is probably a bit backwards.  As we are converting to single
61  * byte formats, perhaps we should not be doing a redundant conversion.
62  * Something to look at for the future.
63  */
64 
65 size_t
__wcsftime_xpg5(wchar_t * wcs,size_t maxsize,const wchar_t * format,const struct tm * timeptr)66 __wcsftime_xpg5(wchar_t *wcs, size_t maxsize, const wchar_t *format,
67     const struct tm *timeptr)
68 {
69 	return (wcsftime_l(wcs, maxsize, format, timeptr,
70 	    uselocale(NULL)));
71 }
72 
73 
74 size_t
wcsftime_l(wchar_t * wcs,size_t maxsize,const wchar_t * format,const struct tm * timeptr,locale_t loc)75 wcsftime_l(wchar_t *wcs, size_t maxsize, const wchar_t *format,
76     const struct tm *timeptr, locale_t loc)
77 {
78 	static const mbstate_t initial = { 0 };
79 	mbstate_t mbs;
80 	char *dst, *sformat;
81 	const char *dstp;
82 	const wchar_t *formatp;
83 	size_t n, sflen;
84 	int sverrno;
85 
86 	sformat = dst = NULL;
87 
88 	/*
89 	 * Convert the supplied format string to a multibyte representation
90 	 * for strftime(), which only handles single-byte characters.
91 	 */
92 	mbs = initial;
93 	formatp = format;
94 	sflen = wcsrtombs_l(NULL, &formatp, 0, &mbs, loc);
95 	if (sflen == (size_t)-1)
96 		goto error;
97 	if ((sformat = malloc(sflen + 1)) == NULL)
98 		goto error;
99 	mbs = initial;
100 	(void) wcsrtombs_l(sformat, &formatp, sflen + 1, &mbs, loc);
101 
102 	/*
103 	 * Allocate memory for longest multibyte sequence that will fit
104 	 * into the caller's buffer and call strftime() to fill it.
105 	 * Then, copy and convert the result back into wide characters in
106 	 * the caller's buffer.
107 	 */
108 	if (LONG_MAX / MB_CUR_MAX <= maxsize) {
109 		/* maxsize is prepostorously large - avoid int. overflow. */
110 		errno = EINVAL;
111 		goto error;
112 	}
113 	if ((dst = malloc(maxsize * MB_CUR_MAX)) == NULL)
114 		goto error;
115 	if (strftime_l(dst, maxsize, sformat, timeptr, loc) == 0)
116 		goto error;
117 	dstp = dst;
118 	mbs = initial;
119 	n = mbsrtowcs_l(wcs, &dstp, maxsize, &mbs, loc);
120 	if (n == (size_t)-2 || n == (size_t)-1 || dstp != NULL)
121 		goto error;
122 
123 	free(sformat);
124 	free(dst);
125 	return (n);
126 
127 error:
128 	sverrno = errno;
129 	free(sformat);
130 	free(dst);
131 	errno = sverrno;
132 	return (0);
133 }
134 
135 size_t
wcsftime(wchar_t * wcs,size_t maxsize,const char * format,const struct tm * timeptr)136 wcsftime(wchar_t *wcs, size_t maxsize, const char *format,
137     const struct tm *timeptr)
138 {
139 	int	len;
140 	wchar_t	*wfmt;
141 	size_t rv;
142 	locale_t loc = uselocale(NULL);
143 
144 	/* Convert the format (mb string) to wide char array */
145 	len = strlen(format) + 1;
146 	wfmt = malloc(sizeof (wchar_t) * len);
147 	if (mbstowcs_l(wfmt, format, len, loc) == (size_t)-1) {
148 		free(wfmt);
149 		return (0);
150 	}
151 	rv = wcsftime_l(wcs, maxsize, wfmt, timeptr, loc);
152 	free(wfmt);
153 	return (rv);
154 }
155