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      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 
     92 static char *
     93 ct_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  */
    108 char *
    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  */
    152 char *
    153 asctime_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 
    162 char *
    163 ctime(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 
    176 char *
    177 asctime(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