xref: /illumos-gate/usr/src/stand/lib/sa/time.c (revision 7c478bd95313f5f23a4c958a745db2134aa03244)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2002-2003 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  *
26  * Time routines, snagged from libc.
27  */
28 
29 #pragma ident	"%Z%%M%	%I%	%E% SMI"
30 
31 #include <errno.h>
32 #include <sys/types.h>
33 #include <sys/bootvfs.h>
34 #include <sys/salib.h>
35 #include <sys/promif.h>
36 #include <stdio.h>
37 #include <time.h>
38 
39 #define	CBUFSIZ 26
40 
41 static time_t	start_time, secs_since_boot;
42 
43 const int	__year_lengths[2] = {
44 	DAYS_PER_NYEAR, DAYS_PER_LYEAR
45 };
46 const int	__mon_lengths[2][MONS_PER_YEAR] = {
47 	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31,
48 	31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
49 };
50 
51 /*
52  * Initializes our "clock" to the creation date of /timestamp, which is
53  * made on the fly for us by the web server. Thereafter, time() will keep
54  * time sort of up to date.
55  */
56 void
57 init_boot_time(void)
58 {
59 	struct stat sb;
60 
61 	if (start_time == 0) {
62 		if (stat("/timestamp", &sb) < 0)
63 			prom_panic("init_boot_time: cannot stat /timestamp");
64 
65 		start_time = sb.st_ctim.tv_sec;
66 		secs_since_boot = prom_gettime() / 1000;
67 	}
68 }
69 
70 /*
71  * Time is crudely incremented.
72  */
73 time_t
74 time(time_t *tloc)
75 {
76 	time_t	time_now;
77 
78 	time_now = start_time + ((prom_gettime() / 1000) - secs_since_boot);
79 
80 	if (tloc != NULL)
81 		*tloc = time_now;
82 
83 	if (start_time == 0)
84 		return (0);
85 	else
86 		return (time_now);
87 }
88 
89 struct tm *
90 gmtime(const time_t *clock)
91 {
92 	static struct tm	result;
93 	struct tm	*tmp;
94 	long		days;
95 	int		rem;
96 	long		y;
97 	long		newy;
98 	const int	*ip;
99 
100 	tmp = &result;
101 	days = *clock / SECS_PER_DAY;
102 	rem = *clock % SECS_PER_DAY;
103 	while (rem < 0) {
104 		rem += SECS_PER_DAY;
105 		--days;
106 	}
107 	while (rem >= SECS_PER_DAY) {
108 		rem -= SECS_PER_DAY;
109 		++days;
110 	}
111 	tmp->tm_hour = (int)(rem / SECS_PER_HOUR);
112 	rem = rem % SECS_PER_HOUR;
113 	tmp->tm_min = (int)(rem / SECS_PER_MIN);
114 	tmp->tm_sec = (int)(rem % SECS_PER_MIN);
115 	tmp->tm_wday = (int)((EPOCH_WDAY + days) % DAYS_PER_WEEK);
116 	if (tmp->tm_wday < 0)
117 		tmp->tm_wday += DAYS_PER_WEEK;
118 	y = EPOCH_YEAR;
119 
120 #define	LEAPS_THRU_END_OF(y)    ((y) / 4 - (y) / 100 + (y) / 400)
121 
122 	while (days < 0 || days >= (long)__year_lengths[isleap(y)]) {
123 		newy = y + days / DAYS_PER_NYEAR;
124 		if (days < 0)
125 			--newy;
126 		days -= ((long)newy - (long)y) * DAYS_PER_NYEAR +
127 			LEAPS_THRU_END_OF(newy > 0 ? newy - 1L : newy) -
128 			LEAPS_THRU_END_OF(y > 0 ? y - 1L : y);
129 		y = newy;
130 	}
131 
132 	tmp->tm_year = y - TM_YEAR_BASE;
133 	tmp->tm_yday = days;
134 	ip = __mon_lengths[isleap(y)];
135 	for (tmp->tm_mon = 0; days >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
136 		days = days - ip[tmp->tm_mon];
137 	tmp->tm_mday = (days + 1);
138 	tmp->tm_isdst = 0;
139 	return (tmp);
140 }
141 
142 /*
143  * The standalone booter runs in GMT.
144  */
145 struct tm *
146 localtime(const time_t *clock)
147 {
148 	return (gmtime(clock));
149 }
150 
151 static char *
152 ct_numb(char *cp, int n)
153 {
154 	cp++;
155 	if (n >= 10)
156 		*cp++ = (n / 10) % 10 + '0';
157 	else
158 		*cp++ = ' ';		/* Pad with blanks */
159 	*cp++ = n % 10 + '0';
160 	return (cp);
161 }
162 
163 char *
164 asctime(const struct tm *t)
165 {
166 	char *cp;
167 	const char *ncp;
168 	const int *tp;
169 	const char *Date = "Day Mon 00 00:00:00 1900\n";
170 	const char *Day  = "SunMonTueWedThuFriSat";
171 	const char *Month = "JanFebMarAprMayJunJulAugSepOctNovDec";
172 	static char cbuf[CBUFSIZ];
173 
174 	cp = cbuf;
175 	for (ncp = Date; *cp++ = *ncp++; /* */);
176 	ncp = Day + (3 * t->tm_wday);
177 	cp = cbuf;
178 	*cp++ = *ncp++;
179 	*cp++ = *ncp++;
180 	*cp++ = *ncp++;
181 	cp++;
182 	tp = &t->tm_mon;
183 	ncp = Month + ((*tp) * 3);
184 	*cp++ = *ncp++;
185 	*cp++ = *ncp++;
186 	*cp++ = *ncp++;
187 	cp = ct_numb(cp, *--tp);
188 	cp = ct_numb(cp, *--tp + 100);
189 	cp = ct_numb(cp, *--tp + 100);
190 	--tp;
191 	cp = ct_numb(cp, *tp + 100);
192 	if (t->tm_year < 100) {
193 		/* Common case: "19" already in buffer */
194 		cp += 2;
195 	} else if (t->tm_year < 8100) {
196 		cp = ct_numb(cp, (1900 + t->tm_year) / 100);
197 		cp--;
198 	} else {
199 		/* Only 4-digit years are supported */
200 		errno = EOVERFLOW;
201 		return (NULL);
202 	}
203 	(void) ct_numb(cp, t->tm_year + 100);
204 	return (cbuf);
205 }
206 
207 char *
208 ctime(const time_t *t)
209 {
210 	return (asctime(localtime(t)));
211 }
212