1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27/*	Copyright (c) 1988 AT&T	*/
28/*	  All Rights Reserved  	*/
29
30#pragma ident	"%Z%%M%	%I%	%E% SMI"
31
32/*
33 * This routine converts time as follows.
34 * The epoch is 0000 Jan 1 1970 GMT.
35 * The argument time is in seconds since then.
36 * The localtime(t) entry returns a pointer to an array
37 * containing
38 *  seconds (0-59)
39 *  minutes (0-59)
40 *  hours (0-23)
41 *  day of month (1-31)
42 *  month (0-11)
43 *  year-1970
44 *  weekday (0-6, Sun is 0)
45 *  day of the year
46 *  daylight savings flag
47 *
48 * The routine corrects for daylight saving
49 * time and will work in any time zone provided
50 * "timezone" is adjusted to the difference between
51 * Greenwich and local standard time (measured in seconds).
52 * In places like Michigan "daylight" must
53 * be initialized to 0 to prevent the conversion
54 * to daylight time.
55 * There is a table which accounts for the peculiarities
56 * undergone by daylight time in 1974-1975.
57 *
58 * The routine does not work
59 * in Saudi Arabia which runs on Solar time.
60 *
61 * asctime(tvec)
62 * where tvec is produced by localtime
63 * returns a ptr to a character string
64 * that has the ascii time in the form
65 *	Thu Jan 01 00:00:00 1970\n\0
66 *	01234567890123456789012345
67 *	0	  1	    2
68 *
69 * ctime(t) just calls localtime, then asctime.
70 *
71 * tzset() looks for an environment variable named
72 * TZ.
73 * If the variable is present, it will set the external
74 * variables "timezone", "altzone", "daylight", and "tzname"
75 * appropriately. It is called by localtime, and
76 * may also be called explicitly by the user.
77 */
78
79#include "lint.h"
80#include <mtlib.h>
81#include <sys/types.h>
82#include <time.h>
83#include <errno.h>
84#include <thread.h>
85#include <synch.h>
86#include "libc.h"
87#include "tsd.h"
88
89#define	dysize(A) (((A)%4)? 365: 366)
90#define	CBUFSIZ 26
91
92static char *
93ct_numb(char *cp, int n, char pad)
94{
95	cp++;
96	if (n >= 10)
97		*cp++ = (n / 10) % 10 + '0';
98	else
99		*cp++ = pad;
100	*cp++ = n % 10 + '0';
101	return (cp);
102}
103
104/*
105 * POSIX.1c standard version of the function asctime_r.
106 * User gets it via static asctime_r from the header file.
107 */
108char *
109__posix_asctime_r(const struct tm *t, char *cbuf)
110{
111	char *cp;
112	const char *ncp;
113	const char *Date = "Day Mon 00 00:00:00 YYYY\n";
114	const char *Day  = "SunMonTueWedThuFriSat";
115	const char *Month = "JanFebMarAprMayJunJulAugSepOctNovDec";
116
117	int year = t->tm_year + 1900;
118
119	cp = cbuf;
120	for (ncp = Date; *cp++ = *ncp++; /* */)
121		;
122	ncp = Day + (3 * t->tm_wday);
123	cp = cbuf;
124	*cp++ = *ncp++;
125	*cp++ = *ncp++;
126	*cp++ = *ncp++;
127	cp++;
128	ncp = Month + (3 * t->tm_mon);
129	*cp++ = *ncp++;
130	*cp++ = *ncp++;
131	*cp++ = *ncp++;
132	cp = ct_numb(cp, t->tm_mday, ' ');
133	cp = ct_numb(cp, t->tm_hour, '0');
134	cp = ct_numb(cp, t->tm_min, '0');
135	cp = ct_numb(cp, t->tm_sec, '0');
136
137	if (year < 0 || year >= 10000) {
138		/* Only positive, 4-digit years are supported */
139		errno = EOVERFLOW;
140		return (NULL);
141	}
142	cp = ct_numb(cp, year / 100, '0');
143	cp--;
144	(void) ct_numb(cp, year, '0');
145	return (cbuf);
146}
147
148/*
149 * POSIX.1c Draft-6 version of the function asctime_r.
150 * It was implemented by Solaris 2.3.
151 */
152char *
153asctime_r(const struct tm *t, char *cbuf, int buflen)
154{
155	if (buflen < CBUFSIZ) {
156		errno = ERANGE;
157		return (NULL);
158	}
159	return (__posix_asctime_r(t, cbuf));
160}
161
162char *
163ctime(const time_t *t)
164{
165	char *cbuf = tsdalloc(_T_CTIME, CBUFSIZ, NULL);
166	struct tm *p;
167
168	if (cbuf == NULL)
169		return (NULL);
170	p = localtime(t);
171	if (p == NULL)
172		return (NULL);
173	return (__posix_asctime_r(p, cbuf));
174}
175
176char *
177asctime(const struct tm *t)
178{
179	char *cbuf = tsdalloc(_T_CTIME, CBUFSIZ, NULL);
180
181	if (cbuf == NULL)
182		return (NULL);
183	return (__posix_asctime_r(t, cbuf));
184}
185