arpadate.c revision 42575 
1/*
2 * Copyright (c) 1998 Sendmail, Inc.  All rights reserved.
3 * Copyright (c) 1983, 1995-1997 Eric P. Allman.  All rights reserved.
4 * Copyright (c) 1988, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * By using this file, you agree to the terms and conditions set
8 * forth in the LICENSE file which can be found at the top level of
9 * the sendmail distribution.
10 *
11 */
12
13#ifndef lint
14static char sccsid[] = "@(#)arpadate.c	8.12 (Berkeley) 5/19/1998";
15#endif /* not lint */
16
17# include "sendmail.h"
18
19/*
20**  ARPADATE -- Create date in ARPANET format
21**
22**	Parameters:
23**		ud -- unix style date string.  if NULL, one is created.
24**
25**	Returns:
26**		pointer to an ARPANET date field
27**
28**	Side Effects:
29**		none
30**
31**	WARNING:
32**		date is stored in a local buffer -- subsequent
33**		calls will overwrite.
34**
35**	Bugs:
36**		Timezone is computed from local time, rather than
37**		from whereever (and whenever) the message was sent.
38**		To do better is very hard.
39**
40**		Some sites are now inserting the timezone into the
41**		local date.  This routine should figure out what
42**		the format is and work appropriately.
43*/
44
45#ifndef TZNAME_MAX
46# define TZNAME_MAX	50	/* max size of timezone */
47#endif
48
49/* values for TZ_TYPE */
50#define TZ_NONE		0	/* no character timezone support */
51#define TZ_TM_NAME	1	/* use tm->tm_name */
52#define TZ_TM_ZONE	2	/* use tm->tm_zone */
53#define TZ_TZNAME	3	/* use tzname[] */
54#define TZ_TIMEZONE	4	/* use timezone() */
55
56char *
57arpadate(ud)
58	register char *ud;
59{
60	register char *p;
61	register char *q;
62	register int off;
63	register int i;
64	register struct tm *lt;
65	time_t t;
66	struct tm gmt;
67	char *tz;
68	static char b[43 + TZNAME_MAX];
69
70	/*
71	**  Get current time.
72	**	This will be used if a null argument is passed and
73	**	to resolve the timezone.
74	*/
75
76	(void) time(&t);
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	gmt = *gmtime(&t);
125	lt = localtime(&t);
126
127	off = (lt->tm_hour - gmt.tm_hour) * 60 + lt->tm_min - gmt.tm_min;
128
129	/* assume that offset isn't more than a day ... */
130	if (lt->tm_year < gmt.tm_year)
131		off -= 24 * 60;
132	else if (lt->tm_year > gmt.tm_year)
133		off += 24 * 60;
134	else if (lt->tm_yday < gmt.tm_yday)
135		off -= 24 * 60;
136	else if (lt->tm_yday > gmt.tm_yday)
137		off += 24 * 60;
138
139	*q++ = ' ';
140	if (off == 0)
141	{
142		*q++ = 'G';
143		*q++ = 'M';
144		*q++ = 'T';
145	}
146	else
147	{
148		tz = NULL;
149#if TZ_TYPE == TZ_TM_NAME
150		tz = lt->tm_name;
151#endif
152#if TZ_TYPE == TZ_TM_ZONE
153		tz = lt->tm_zone;
154#endif
155#if TZ_TYPE == TZ_TZNAME
156		{
157			extern char *tzname[];
158
159			tz = tzname[lt->tm_isdst];
160		}
161#endif
162#if TZ_TYPE == TZ_TIMEZONE
163		{
164			extern char *timezone();
165
166			tz = timezone(off, lt->tm_isdst);
167		}
168#endif
169		if (off < 0)
170		{
171			off = -off;
172			*q++ = '-';
173		}
174		else
175			*q++ = '+';
176
177		if (off >= 24*60)		/* should be impossible */
178			off = 23*60+59;		/* if not, insert silly value */
179
180		*q++ = (off / 600) + '0';
181		*q++ = (off / 60) % 10 + '0';
182		off %= 60;
183		*q++ = (off / 10) + '0';
184		*q++ = (off % 10) + '0';
185		if (tz != NULL && *tz != '\0')
186		{
187			*q++ = ' ';
188			*q++ = '(';
189			while (*tz != '\0' && q < &b[sizeof b - 3])
190				*q++ = *tz++;
191			*q++ = ')';
192		}
193	}
194	*q = '\0';
195
196	return (b);
197}
198