1 /*
2  * Copyright (c) 1983 Eric P. Allman
3  * Copyright (c) 1988 Regents of the University of California.
4  * All rights reserved.
5  *
6  * %sccs.include.redist.c%
7  */
8 
9 #ifndef lint
10 static char sccsid[] = "@(#)arpadate.c	6.3 (Berkeley) 01/21/93";
11 #endif /* not lint */
12 
13 # include "sendmail.h"
14 # include <sys/types.h>
15 
16 /*
17 **  ARPADATE -- Create date in ARPANET format
18 **
19 **	Parameters:
20 **		ud -- unix style date string.  if NULL, one is created.
21 **
22 **	Returns:
23 **		pointer to an ARPANET date field
24 **
25 **	Side Effects:
26 **		none
27 **
28 **	WARNING:
29 **		date is stored in a local buffer -- subsequent
30 **		calls will overwrite.
31 **
32 **	Bugs:
33 **		Timezone is computed from local time, rather than
34 **		from whereever (and whenever) the message was sent.
35 **		To do better is very hard.
36 **
37 **		Some sites are now inserting the timezone into the
38 **		local date.  This routine should figure out what
39 **		the format is and work appropriately.
40 */
41 
42 char *
43 arpadate(ud)
44 	register char *ud;
45 {
46 	register char *p;
47 	register char *q;
48 	register int off;
49 	register int i;
50 	register struct tm *lt;
51 	time_t t;
52 	struct tm gmt;
53 	static char b[40];
54 
55 	/*
56 	**  Get current time.
57 	**	This will be used if a null argument is passed and
58 	**	to resolve the timezone.
59 	*/
60 
61 	(void) time(&t);
62 	if (ud == NULL)
63 		ud = ctime(&t);
64 
65 	/*
66 	**  Crack the UNIX date line in a singularly unoriginal way.
67 	*/
68 
69 	q = b;
70 
71 	p = &ud[0];		/* Mon */
72 	*q++ = *p++;
73 	*q++ = *p++;
74 	*q++ = *p++;
75 	*q++ = ',';
76 	*q++ = ' ';
77 
78 	p = &ud[8];		/* 16 */
79 	if (*p == ' ')
80 		p++;
81 	else
82 		*q++ = *p++;
83 	*q++ = *p++;
84 	*q++ = ' ';
85 
86 	p = &ud[4];		/* Sep */
87 	*q++ = *p++;
88 	*q++ = *p++;
89 	*q++ = *p++;
90 	*q++ = ' ';
91 
92 	p = &ud[20];		/* 1979 */
93 	*q++ = *p++;
94 	*q++ = *p++;
95 	*q++ = *p++;
96 	*q++ = *p++;
97 	*q++ = ' ';
98 
99 	p = &ud[11];		/* 01:03:52 */
100 	for (i = 8; i > 0; i--)
101 		*q++ = *p++;
102 
103 	/*
104 	 * should really get the timezone from the time in "ud" (which
105 	 * is only different if a non-null arg was passed which is different
106 	 * from the current time), but for all practical purposes, returning
107 	 * the current local zone will do (its all that is ever needed).
108 	 */
109 	gmt = *gmtime(&t);
110 	lt = localtime(&t);
111 
112 	off = (lt->tm_hour - gmt.tm_hour) * 60 + lt->tm_min - gmt.tm_min;
113 
114 	/* assume that offset isn't more than a day ... */
115 	if (lt->tm_year < gmt.tm_year)
116 		off -= 24 * 60;
117 	else if (lt->tm_year > gmt.tm_year)
118 		off += 24 * 60;
119 	else if (lt->tm_yday < gmt.tm_yday)
120 		off -= 24 * 60;
121 	else if (lt->tm_yday > gmt.tm_yday)
122 		off += 24 * 60;
123 
124 	*q++ = ' ';
125 	if (off == 0) {
126 		*q++ = 'G';
127 		*q++ = 'M';
128 		*q++ = 'T';
129 	} else {
130 		if (off < 0) {
131 			off = -off;
132 			*q++ = '-';
133 		} else
134 			*q++ = '+';
135 
136 		if (off >= 24*60)		/* should be impossible */
137 			off = 23*60+59;		/* if not, insert silly value */
138 
139 		*q++ = (off / 600) + '0';
140 		*q++ = (off / 60) % 10 + '0';
141 		off %= 60;
142 		*q++ = (off / 10) + '0';
143 		*q++ = (off % 10) + '0';
144 	}
145 	*q = '\0';
146 
147 	return (b);
148 }
149 
150 /*
151 **  NEXTATOM -- Return pointer to next atom in header
152 **		(skip whitespace and comments)
153 **
154 **	Parameters:
155 **		s -- pointer to header string
156 **
157 **	Returns:
158 **		pointer advanced to next non-comment header atom
159 **
160 **	Side Effects:
161 **		none
162 */
163 
164 static char *
165 nextatom(s)
166 	char *s;
167 {
168 	char *p;
169 
170 	for (p = s;
171 	     *p && (*p == ' ' || *p == '\t' || *p == '\n' || *p == '(');
172 	     p++)
173 	{
174 		if (*p == '(')
175 		{
176 			int nested = 0;
177 
178 			/* ignore comments */
179 			p++;
180 			for (; *p; p++)
181 			{
182 				if (*p == '(')
183 					nested++;
184 				else if (*p == ')')
185 					if (!nested)
186 						break;
187 					else
188 						nested--;
189 			}
190 		}
191 	}
192 	return (p);
193 }
194 
195 /*
196 **  ARPATOUNIX -- Convert RFC-822/1123 date-time specification to ctime format.
197 **
198 **	Parameters:
199 **		s -- pointer to date string
200 **
201 **	Returns:
202 **		pointer to a string in ctime format
203 **
204 **	Side Effects:
205 **		Calls asctime() which modifies its static area.
206 **
207 **	Syntax:
208 **		date-time field specification from RFC822
209 **		as amended by RFC 1123:
210 **
211 **			[ day "," ] 1*2DIGIT month 2*4DIGIT \
212 **			2DIGIT ":" 2DIGIT [ ":" 2DIGIT  ] zone
213 **
214 **		Day can be "Mon" "Tue" "Wed" "Thu" "Fri" "Sat" "Sun"
215 **			(case-insensitive)
216 **		Month can be "Jan" "Feb" "Mar" "Apr" "May" "Jun" "Jul"
217 **			"Aug" "Sep" "Oct" "Nov" "Dec" (also case-insensitive)
218 **		Zone can be "UT" "GMT" "EST" "EDT" "CST" "CDT" "MST" "MDT"
219 **			"PST" "PDT" or "+"4*DIGIT or "-"4*DIGIT
220 **			(case-insensitive; military zones not useful
221 **			per RFC1123)
222 **		Additional whitespace or comments may occur.
223 */
224 
225 static char MonthDays[] = {
226 	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
227 };
228 
229 char *
230 arpatounix(s, e)
231 	char	*s;
232 	ENVELOPE *e;
233 {
234 	char *p;
235 	char *n;
236 	int h_offset = 0;		/* hours */
237 	int m_offset = 0;		/* minutes */
238 	struct tm tm;
239 	extern char *DowList[];		/* defined in collect.c */
240 	extern char *MonthList[];	/* defined in collect.c */
241 
242 	bzero((char *) &tm, sizeof tm);
243 	tm.tm_wday = -1;	/* impossible value */
244 	p = nextatom (s);
245 
246 	/* next atom must be a day or a date */
247 	if (isalpha((int) *p))
248 	{
249 		/* day */
250 		for (tm.tm_wday = 0; DowList[tm.tm_wday]; tm.tm_wday++)
251 		{
252 			if (strncasecmp (p, DowList[tm.tm_wday], 3))
253 				continue;
254 			else
255 			{
256 				p += 3;
257 				break;
258 			}
259 		}
260 		p = nextatom(p);		/* ',' */
261 		if (*p == ',')
262 			p = nextatom(++p);
263 	}
264 
265 	/* now must have date */
266 	tm.tm_mday = atoi(p);
267 	while (isdigit((int) *p))		/* skip over date */
268 		p++;
269 	p = nextatom(p);			/* point to month name */
270 	for (tm.tm_mon = 0; MonthList[tm.tm_mon]; tm.tm_mon++)
271 	{
272 		if (strncasecmp(p, MonthList[tm.tm_mon], 3) == 0)
273 		{
274 			p += 3;
275 			break;
276 		}
277 	}
278 	p = nextatom(p);			/* year */
279 	tm.tm_year = atoi(p);
280 
281 	/* if this was 4 digits, subtract 1900 */
282 	if (tm.tm_year > 999)
283 		tm.tm_year -= 1900;
284 	else
285 	{
286 		/* if 2 or 3 digits, guess which century and convert */
287 		time_t now;
288 		struct tm *gmt;
289 
290 		(void) time(&now);
291 		gmt = gmtime(&now);
292 
293 		/* more likely +1 day than -100(0) years */
294 		if (gmt->tm_mon == 11 && gmt->tm_mday == 31 &&
295 		    tm.tm_mon == 0 && tm.tm_mday == 1)
296 			gmt->tm_year++;
297 		if (tm.tm_year > 99)
298 		{
299 			/* 3 digits */
300 			tm.tm_year += ((gmt->tm_year + 900 - tm.tm_year) / 1000) * 1000;
301 		}
302 		else
303 		{
304 			/* 2 digits */
305 			tm.tm_year += ((gmt->tm_year - tm.tm_year) / 100) * 100;
306 		}
307 	}
308 	while (isdigit((int) *p))	/* skip over year */
309 		p++;
310 	p = nextatom(p);		/* hours */
311 	tm.tm_hour = atoi(p);
312 	while (isdigit((int) *p))	/* skip over hours */
313 		p++;
314 	p = nextatom(p);		/* colon */
315 	if (*p == ':')
316 		p = nextatom(++p);
317 	p = nextatom(p);		/* minutes */
318 	tm.tm_min = atoi(p);
319 	while (isdigit((int) *p))	/* skip over minutes */
320 		p++;
321 	p = nextatom(p);		/* colon or zone */
322 	if (*p == ':')			/* have seconds field */
323 	{
324 		p = nextatom(++p);
325 		tm.tm_sec = atoi(p);
326 		while (isdigit((int) *p))	/* skip over seconds */
327 			p++;
328 	}
329 	p = nextatom(p);		/* zone */
330 	if (!strncasecmp(p, "UT", 2) || !strncasecmp(p, "GMT", 3))
331 		;
332 	else if (!strncasecmp(p, "EDT", 3))
333 		h_offset = -4;
334 	else if (!strncasecmp(p, "EST", 3))
335 	{
336 		h_offset = -5;
337 		tm.tm_isdst = 1;
338 	}
339 	else if (!strncasecmp(p, "CDT", 3))
340 		h_offset = -5;
341 	else if (!strncasecmp(p, "CST", 3))
342 	{
343 		h_offset = -6;
344 		tm.tm_isdst = 1;
345 	}
346 	else if (!strncasecmp(p, "MDT", 3))
347 		h_offset = -6;
348 	else if (!strncasecmp(p, "MST", 3))
349 	{
350 		h_offset = -7;
351 		tm.tm_isdst = 1;
352 	}
353 	else if (!strncasecmp(p, "PDT", 3))
354 		h_offset = -7;
355 	else if (!strncasecmp(p, "PST", 3))
356 	{
357 		h_offset = -8;
358 		tm.tm_isdst = 1;
359 	}
360 	else if (*p == '+')
361 	{
362 		int off;
363 
364 		off = atoi(++p);
365 		h_offset = off / 100;
366 		m_offset = off % 100;
367 	}
368 	else if (*p == '-')
369 	{
370 		int off;
371 
372 		off = atoi(++p);
373 		h_offset = off / -100;
374 		m_offset = -1 * (off % 100);
375 	}
376 	else
377 	{
378 #ifdef LOG
379 		if (LogLevel > 0)
380 			syslog(LOG_NOTICE, "%s: arpatounix: unparseable date: %s",
381 				e->e_id, s);
382 #endif /* LOG */
383 		return(NULL);
384 	}
385 
386 	/* is the year a leap year? */
387 	if ((tm.tm_year % 4 == 0) &&
388 	    ((tm.tm_year % 100 != 0) || (tm.tm_year % 400 == 0)))
389 		MonthDays[2] = 29;
390 	else
391 		MonthDays[2] = 28;
392 
393 	/* apply offset */
394 	if (h_offset || m_offset)
395 	{
396 		tm.tm_min += m_offset;
397 		tm.tm_hour += h_offset;
398 
399 		/* normalize */
400 		if (tm.tm_min < 0)
401 		{
402 			tm.tm_hour--;
403 			tm.tm_min += 60;
404 		}
405 		else if (tm.tm_min > 59)
406 		{
407 			tm.tm_hour++;
408 			tm.tm_min -= 60;
409 		}
410 		if (tm.tm_hour < 0)
411 		{
412 			tm.tm_mday--;
413 			tm.tm_wday--;
414 			tm.tm_hour += 24;
415 		}
416 		else if (tm.tm_hour > 23)
417 		{
418 			tm.tm_mday++;
419 			tm.tm_wday++;
420 			tm.tm_hour -= 24;
421 		}
422 		if (tm.tm_mday < 1)
423 		{
424 			if (--tm.tm_mon == -1)
425 			{
426 				tm.tm_mon = 11;
427 				tm.tm_year--;
428 
429 				/* is the year a leap year? */
430 				if ((tm.tm_year % 4 == 0) &&
431 				    ((tm.tm_year % 100 != 0) || (tm.tm_year % 400 == 0)))
432 					MonthDays[2] = 29;
433 				else
434 					MonthDays[2] = 28;
435 			}
436 			tm.tm_mday += MonthDays[tm.tm_mon];
437 		}
438 		else if (tm.tm_mday > MonthDays[tm.tm_mon])
439 		{
440 			tm.tm_mday -= MonthDays[tm.tm_mon++];
441 			if (tm.tm_mon > 11)
442 			{
443 				tm.tm_mon = 0;
444 				tm.tm_year++;
445 
446 				/*
447 				* Don't have to worry about leap years in
448 				* January.
449 				*/
450 			}
451 		}
452 	}
453 
454 	/* determine day of week if not set from RFC822/1123 line */
455 	if (tm.tm_wday < 0)
456 	{
457 		int i;
458 
459 		for (i = 0; i < tm.tm_mon; i++)
460 			tm.tm_yday += MonthDays[i];
461 		tm.tm_yday += tm.tm_mday;
462 
463 		/* I wouldn't change these constants if I were you... */
464 		tm.tm_wday = (int) (((((tm.tm_year + 699L) * 146097L) / 400L) + tm.tm_yday) % 7);
465 	}
466 
467 	/* now get UT */
468 	if ((p = asctime(&tm)) == NULL || *p == '\0' || strlen(p) < 25)
469 	{
470 #ifdef LOG
471 		if (LogLevel > 0)
472 			syslog(LOG_NOTICE, "%s: arpatounix: asctime failed: %s",
473 				e->e_id, s);
474 #endif /* LOG */
475 		return(NULL);
476 	}
477 	if ((n = index(p, '\n')) != NULL)
478 		*n = '\0';
479 	return(p);
480 }
481