1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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/types.h>
33 #include <sys/time.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #define TZ_MAX_CHARS 255
38
39 static char *_tztab(int, int);
40
41 /*
42 * timezone --
43 * The arguments are the number of minutes of time you are westward
44 * from Greenwich and whether DST is in effect. It returns a string
45 * giving the name of the local timezone. Should be replaced, in the
46 * application code, by a call to localtime.
47 */
48
49 static char czone[TZ_MAX_CHARS]; /* space for zone name */
50
51 char *
__timezone_compat(int zone,int dst)52 __timezone_compat(int zone, int dst)
53 {
54 char *beg,
55 *end;
56
57 if ( (beg = getenv("TZNAME")) ) { /* set in environment */
58 if ((end = strchr(beg, ','))) { /* "PST,PDT" */
59 if (dst)
60 return(++end);
61 *end = '\0';
62 (void)strncpy(czone,beg,sizeof(czone) - 1);
63 czone[sizeof(czone) - 1] = '\0';
64 *end = ',';
65 return(czone);
66 }
67 return(beg);
68 }
69 return(_tztab(zone,dst)); /* default: table or created zone */
70 }
71 __sym_compat(timezone, __timezone_compat, FBSD_1.0);
72
73 static struct zone {
74 int offset;
75 char *stdzone;
76 char *dlzone;
77 } zonetab[] = {
78 {-1*60, "MET", "MET DST"}, /* Middle European */
79 {-2*60, "EET", "EET DST"}, /* Eastern European */
80 {4*60, "AST", "ADT"}, /* Atlantic */
81 {5*60, "EST", "EDT"}, /* Eastern */
82 {6*60, "CST", "CDT"}, /* Central */
83 {7*60, "MST", "MDT"}, /* Mountain */
84 {8*60, "PST", "PDT"}, /* Pacific */
85 #ifdef notdef
86 /* there's no way to distinguish this from WET */
87 {0, "GMT", 0}, /* Greenwich */
88 #endif
89 {0*60, "WET", "WET DST"}, /* Western European */
90 {-10*60,"EST", "EST"}, /* Aust: Eastern */
91 {-10*60+30,"CST", "CST"}, /* Aust: Central */
92 {-8*60, "WST", 0}, /* Aust: Western */
93 {-1}
94 };
95
96 /*
97 * _tztab --
98 * check static tables or create a new zone name; broken out so that
99 * we can make a guess as to what the zone is if the standard tables
100 * aren't in place in /etc. DO NOT USE THIS ROUTINE OUTSIDE OF THE
101 * STANDARD LIBRARY.
102 */
103 static char *
_tztab(int zone,int dst)104 _tztab(int zone, int dst)
105 {
106 struct zone *zp;
107 char sign;
108
109 for (zp = zonetab; zp->offset != -1;++zp) /* static tables */
110 if (zp->offset == zone) {
111 if (dst && zp->dlzone)
112 return(zp->dlzone);
113 if (!dst && zp->stdzone)
114 return(zp->stdzone);
115 }
116
117 if (zone < 0) { /* create one */
118 zone = -zone;
119 sign = '+';
120 }
121 else
122 sign = '-';
123 (void)snprintf(czone, sizeof(czone),
124 "GMT%c%d:%02d",sign,zone / 60,zone % 60);
125 return(czone);
126 }
127