xref: /freebsd/contrib/sendmail/src/arpadate.c (revision e2c0e292e8a7ca00ba99bcfccc9e637f45c3e8b1)
1 /*
2  * Copyright (c) 1998-2001 Proofpoint, Inc. and its suppliers.
3  *	All rights reserved.
4  * Copyright (c) 1983, 1995-1997 Eric P. Allman.  All rights reserved.
5  * Copyright (c) 1988, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * By using this file, you agree to the terms and conditions set
9  * forth in the LICENSE file which can be found at the top level of
10  * the sendmail distribution.
11  *
12  */
13 
14 #include <sendmail.h>
15 
16 SM_RCSID("@(#)$Id: arpadate.c,v 8.32 2013-11-22 20:51:55 ca Exp $")
17 
18 /*
19 **  ARPADATE -- Create date in ARPANET format
20 **
21 **	Parameters:
22 **		ud -- unix style date string.  if NULL, one is created.
23 **
24 **	Returns:
25 **		pointer to an ARPANET date field
26 **
27 **	Side Effects:
28 **		none
29 **
30 **	WARNING:
31 **		date is stored in a local buffer -- subsequent
32 **		calls will overwrite.
33 **
34 **	Bugs:
35 **		Timezone is computed from local time, rather than
36 **		from wherever (and whenever) the message was sent.
37 **		To do better is very hard.
38 **
39 **		Some sites are now inserting the timezone into the
40 **		local date.  This routine should figure out what
41 **		the format is and work appropriately.
42 */
43 
44 #ifndef TZNAME_MAX
45 # define TZNAME_MAX	50	/* max size of timezone */
46 #endif
47 
48 /* values for TZ_TYPE */
49 #define TZ_NONE		0	/* no character timezone support */
50 #define TZ_TM_NAME	1	/* use tm->tm_name */
51 #define TZ_TM_ZONE	2	/* use tm->tm_zone */
52 #define TZ_TZNAME	3	/* use tzname[] */
53 #define TZ_TIMEZONE	4	/* use timezone() */
54 
55 char *
56 arpadate(ud)
57 	register char *ud;
58 {
59 	register char *p;
60 	register char *q;
61 	register int off;
62 	register int i;
63 	register struct tm *lt;
64 	time_t t;
65 	struct tm gmt;
66 	char *tz;
67 	static char b[43 + TZNAME_MAX];
68 
69 	/*
70 	**  Get current time.
71 	**	This will be used if a null argument is passed and
72 	**	to resolve the timezone.
73 	*/
74 
75 	/* SM_REQUIRE(ud == NULL || strlen(ud) >= 23); */
76 	t = curtime();
77 	if (ud == NULL)
78 		ud = ctime(&t);
79 
80 	/*
81 	**  Crack the UNIX date line in a singularly unoriginal way.
82 	*/
83 
84 	q = b;
85 
86 	p = &ud[0];		/* Mon */
87 	*q++ = *p++;
88 	*q++ = *p++;
89 	*q++ = *p++;
90 	*q++ = ',';
91 	*q++ = ' ';
92 
93 	p = &ud[8];		/* 16 */
94 	if (*p == ' ')
95 		p++;
96 	else
97 		*q++ = *p++;
98 	*q++ = *p++;
99 	*q++ = ' ';
100 
101 	p = &ud[4];		/* Sep */
102 	*q++ = *p++;
103 	*q++ = *p++;
104 	*q++ = *p++;
105 	*q++ = ' ';
106 
107 	p = &ud[20];		/* 1979 */
108 	*q++ = *p++;
109 	*q++ = *p++;
110 	*q++ = *p++;
111 	*q++ = *p++;
112 	*q++ = ' ';
113 
114 	p = &ud[11];		/* 01:03:52 */
115 	for (i = 8; i > 0; i--)
116 		*q++ = *p++;
117 
118 	/*
119 	**  should really get the timezone from the time in "ud" (which
120 	**  is only different if a non-null arg was passed which is different
121 	**  from the current time), but for all practical purposes, returning
122 	**  the current local zone will do (its all that is ever needed).
123 	*/
124 
125 	gmt = *gmtime(&t);
126 	lt = localtime(&t);
127 
128 	off = (lt->tm_hour - gmt.tm_hour) * 60 + lt->tm_min - gmt.tm_min;
129 
130 	/* assume that offset isn't more than a day ... */
131 	if (lt->tm_year < gmt.tm_year)
132 		off -= 24 * 60;
133 	else if (lt->tm_year > gmt.tm_year)
134 		off += 24 * 60;
135 	else if (lt->tm_yday < gmt.tm_yday)
136 		off -= 24 * 60;
137 	else if (lt->tm_yday > gmt.tm_yday)
138 		off += 24 * 60;
139 
140 	*q++ = ' ';
141 	if (off == 0)
142 	{
143 		*q++ = 'G';
144 		*q++ = 'M';
145 		*q++ = 'T';
146 	}
147 	else
148 	{
149 		tz = NULL;
150 #if TZ_TYPE == TZ_TM_NAME
151 		tz = lt->tm_name;
152 #endif
153 #if TZ_TYPE == TZ_TM_ZONE
154 		tz = lt->tm_zone;
155 #endif
156 #if TZ_TYPE == TZ_TZNAME
157 		{
158 			extern char *tzname[];
159 
160 			if (lt->tm_isdst > 0)
161 				tz = tzname[1];
162 			else if (lt->tm_isdst == 0)
163 				tz = tzname[0];
164 			else
165 				tz = NULL;
166 		}
167 #endif /* TZ_TYPE == TZ_TZNAME */
168 #if TZ_TYPE == TZ_TIMEZONE
169 		{
170 			extern char *timezone();
171 
172 			tz = timezone(off, lt->tm_isdst);
173 		}
174 #endif /* TZ_TYPE == TZ_TIMEZONE */
175 		if (off < 0)
176 		{
177 			off = -off;
178 			*q++ = '-';
179 		}
180 		else
181 			*q++ = '+';
182 
183 		if (off >= 24*60)		/* should be impossible */
184 			off = 23*60+59;		/* if not, insert silly value */
185 
186 		*q++ = (off / 600) + '0';
187 		*q++ = (off / 60) % 10 + '0';
188 		off %= 60;
189 		*q++ = (off / 10) + '0';
190 		*q++ = (off % 10) + '0';
191 		if (tz != NULL && *tz != '\0')
192 		{
193 			*q++ = ' ';
194 			*q++ = '(';
195 			while (*tz != '\0' && q < &b[sizeof(b) - 3])
196 				*q++ = *tz++;
197 			*q++ = ')';
198 		}
199 	}
200 	*q = '\0';
201 
202 	return b;
203 }
204