1 /* $NetBSD: compat_timezone.c,v 1.5 2024/01/20 14:52:45 christos Exp $ */
2
3 /*
4 * Copyright (c) 1987, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "@(#)timezone.c 8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: compat_timezone.c,v 1.5 2024/01/20 14:52:45 christos Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40
41 #define __LIBC12_SOURCE__
42 #define __TIMEZONE_FUNCTION__
43
44 #include "namespace.h"
45 #include <sys/types.h>
46 #include <time.h>
47 #include <compat/include/time.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <tzfile.h>
52
53 __warn_references(timezone,
54 "warning: reference to compatibility timezone; include <time.h> to generate correct reference")
55
56 /*
57 * timezone --
58 * The arguments are the number of minutes of time you are westward
59 * from Greenwich and whether DST is in effect. It returns a string
60 * giving the name of the local timezone. Should be replaced, in the
61 * application code, by a call to localtime.
62 */
63
64 static char czone[TZ_MAX_CHARS]; /* space for zone name */
65
66 char *
timezone(int zone,int dst)67 timezone(int zone, int dst)
68 {
69 char *beg,
70 *end;
71
72 if ((beg = getenv("TZNAME")) != NULL) { /* set in environment */
73 if ((end = strchr(beg, ',')) != NULL) { /* "PST,PDT" */
74 if (dst)
75 return(++end);
76 *end = '\0';
77 (void)strlcpy(czone, beg, sizeof(czone));
78 *end = ',';
79 return(czone);
80 }
81 return(beg);
82 }
83 return(_tztab(zone,dst)); /* default: table or created zone */
84 }
85
86 static const struct zone {
87 int offset;
88 const char *stdzone;
89 const char *dlzone;
90 } zonetab[] = {
91 { -1*60, "MET", "MET DST" }, /* Middle European */
92 { -2*60, "EET", "EET DST" }, /* Eastern European */
93 { 4*60, "AST", "ADT" }, /* Atlantic */
94 { 5*60, "EST", "EDT" }, /* Eastern */
95 { 6*60, "CST", "CDT" }, /* Central */
96 { 7*60, "MST", "MDT" }, /* Mountain */
97 { 8*60, "PST", "PDT" }, /* Pacific */
98 #ifdef notdef
99 /* there's no way to distinguish this from WET */
100 { 0, "GMT", 0 }, /* Greenwich */
101 #endif
102 { 0*60, "WET", "WET DST" }, /* Western European */
103 { -10*60, "EST", "EST" }, /* Aust: Eastern */
104 { -10*60+30, "CST", "CST" }, /* Aust: Central */
105 { -8*60, "WST", 0 }, /* Aust: Western */
106 { -1, NULL, NULL }
107 };
108
109 /*
110 * _tztab --
111 * check static tables or create a new zone name; broken out so that
112 * we can make a guess as to what the zone is if the standard tables
113 * aren't in place in /etc. DO NOT USE THIS ROUTINE OUTSIDE OF THE
114 * STANDARD LIBRARY.
115 */
116 char *
_tztab(int zone,int dst)117 _tztab(int zone, int dst)
118 {
119 const struct zone *zp;
120 char sign;
121
122 for (zp = zonetab; zp->offset != -1;++zp) /* static tables */
123 if (zp->offset == zone) {
124 if (dst && zp->dlzone)
125 return __UNCONST(zp->dlzone);
126 if (!dst && zp->stdzone)
127 return __UNCONST(zp->stdzone);
128 }
129
130 if (zone < 0) { /* create one */
131 zone = -zone;
132 sign = '+';
133 }
134 else
135 sign = '-';
136 (void)snprintf(czone, TZ_MAX_CHARS, "GMT%c%d:%02d", sign, zone / 60,
137 zone % 60);
138 return(czone);
139 }
140