1 /*
2  * Copyright (c) 1983 Eric P. Allman
3  * Copyright (c) 1988, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * %sccs.include.redist.c%
7  */
8 
9 #ifndef lint
10 static char sccsid[] = "@(#)savemail.c	8.30 (Berkeley) 05/29/94";
11 #endif /* not lint */
12 
13 # include "sendmail.h"
14 # include <pwd.h>
15 
16 /*
17 **  SAVEMAIL -- Save mail on error
18 **
19 **	If mailing back errors, mail it back to the originator
20 **	together with an error message; otherwise, just put it in
21 **	dead.letter in the user's home directory (if he exists on
22 **	this machine).
23 **
24 **	Parameters:
25 **		e -- the envelope containing the message in error.
26 **
27 **	Returns:
28 **		none
29 **
30 **	Side Effects:
31 **		Saves the letter, by writing or mailing it back to the
32 **		sender, or by putting it in dead.letter in her home
33 **		directory.
34 */
35 
36 /* defines for state machine */
37 # define ESM_REPORT	0	/* report to sender's terminal */
38 # define ESM_MAIL	1	/* mail back to sender */
39 # define ESM_QUIET	2	/* messages have already been returned */
40 # define ESM_DEADLETTER	3	/* save in ~/dead.letter */
41 # define ESM_POSTMASTER	4	/* return to postmaster */
42 # define ESM_USRTMP	5	/* save in /usr/tmp/dead.letter */
43 # define ESM_PANIC	6	/* leave the locked queue/transcript files */
44 # define ESM_DONE	7	/* the message is successfully delivered */
45 
46 # ifndef _PATH_VARTMP
47 #  define _PATH_VARTMP	"/usr/tmp/"
48 # endif
49 
50 
51 savemail(e)
52 	register ENVELOPE *e;
53 {
54 	register struct passwd *pw;
55 	register FILE *fp;
56 	int state;
57 	auto ADDRESS *q = NULL;
58 	register char *p;
59 	MCI mcibuf;
60 	char buf[MAXLINE+1];
61 	extern struct passwd *getpwnam();
62 	extern char *ttypath();
63 	typedef int (*fnptr)();
64 	extern bool writable();
65 
66 	if (tTd(6, 1))
67 	{
68 		printf("\nsavemail, errormode = %c, id = %s, ExitStat = %d\n  e_from=",
69 			e->e_errormode, e->e_id == NULL ? "NONE" : e->e_id,
70 			ExitStat);
71 		printaddr(&e->e_from, FALSE);
72 	}
73 
74 	if (e->e_id == NULL)
75 	{
76 		/* can't return a message with no id */
77 		return;
78 	}
79 
80 	/*
81 	**  In the unhappy event we don't know who to return the mail
82 	**  to, make someone up.
83 	*/
84 
85 	if (e->e_from.q_paddr == NULL)
86 	{
87 		e->e_sender = "Postmaster";
88 		if (parseaddr(e->e_sender, &e->e_from,
89 			      RF_COPYPARSE|RF_SENDERADDR, '\0', NULL, e) == NULL)
90 		{
91 			syserr("553 Cannot parse Postmaster!");
92 			ExitStat = EX_SOFTWARE;
93 			finis();
94 		}
95 	}
96 	e->e_to = NULL;
97 
98 	/*
99 	**  Basic state machine.
100 	**
101 	**	This machine runs through the following states:
102 	**
103 	**	ESM_QUIET	Errors have already been printed iff the
104 	**			sender is local.
105 	**	ESM_REPORT	Report directly to the sender's terminal.
106 	**	ESM_MAIL	Mail response to the sender.
107 	**	ESM_DEADLETTER	Save response in ~/dead.letter.
108 	**	ESM_POSTMASTER	Mail response to the postmaster.
109 	**	ESM_PANIC	Save response anywhere possible.
110 	*/
111 
112 	/* determine starting state */
113 	switch (e->e_errormode)
114 	{
115 	  case EM_WRITE:
116 		state = ESM_REPORT;
117 		break;
118 
119 	  case EM_BERKNET:
120 		/* mail back, but return o.k. exit status */
121 		ExitStat = EX_OK;
122 
123 		/* fall through.... */
124 
125 	  case EM_MAIL:
126 		state = ESM_MAIL;
127 		break;
128 
129 	  case EM_PRINT:
130 	  case '\0':
131 		state = ESM_QUIET;
132 		break;
133 
134 	  case EM_QUIET:
135 		/* no need to return anything at all */
136 		return;
137 
138 	  default:
139 		syserr("554 savemail: bogus errormode x%x\n", e->e_errormode);
140 		state = ESM_MAIL;
141 		break;
142 	}
143 
144 	/* if this is already an error response, send to postmaster */
145 	if (bitset(EF_RESPONSE, e->e_flags))
146 	{
147 		if (e->e_parent != NULL &&
148 		    bitset(EF_RESPONSE, e->e_parent->e_flags))
149 		{
150 			/* got an error sending a response -- can it */
151 			return;
152 		}
153 		state = ESM_POSTMASTER;
154 	}
155 
156 	while (state != ESM_DONE)
157 	{
158 		if (tTd(6, 5))
159 			printf("  state %d\n", state);
160 
161 		switch (state)
162 		{
163 		  case ESM_QUIET:
164 			if (e->e_from.q_mailer == LocalMailer)
165 				state = ESM_DEADLETTER;
166 			else
167 				state = ESM_MAIL;
168 			break;
169 
170 		  case ESM_REPORT:
171 
172 			/*
173 			**  If the user is still logged in on the same terminal,
174 			**  then write the error messages back to hir (sic).
175 			*/
176 
177 			p = ttypath();
178 			if (p == NULL || freopen(p, "w", stdout) == NULL)
179 			{
180 				state = ESM_MAIL;
181 				break;
182 			}
183 
184 			expand("\201n", buf, &buf[sizeof buf - 1], e);
185 			printf("\r\nMessage from %s...\r\n", buf);
186 			printf("Errors occurred while sending mail.\r\n");
187 			if (e->e_xfp != NULL)
188 			{
189 				(void) fflush(e->e_xfp);
190 				fp = fopen(queuename(e, 'x'), "r");
191 			}
192 			else
193 				fp = NULL;
194 			if (fp == NULL)
195 			{
196 				syserr("Cannot open %s", queuename(e, 'x'));
197 				printf("Transcript of session is unavailable.\r\n");
198 			}
199 			else
200 			{
201 				printf("Transcript follows:\r\n");
202 				while (fgets(buf, sizeof buf, fp) != NULL &&
203 				       !ferror(stdout))
204 					fputs(buf, stdout);
205 				(void) xfclose(fp, "savemail transcript", e->e_id);
206 			}
207 			printf("Original message will be saved in dead.letter.\r\n");
208 			state = ESM_DEADLETTER;
209 			break;
210 
211 		  case ESM_MAIL:
212 			/*
213 			**  If mailing back, do it.
214 			**	Throw away all further output.  Don't alias,
215 			**	since this could cause loops, e.g., if joe
216 			**	mails to joe@x, and for some reason the network
217 			**	for @x is down, then the response gets sent to
218 			**	joe@x, which gives a response, etc.  Also force
219 			**	the mail to be delivered even if a version of
220 			**	it has already been sent to the sender.
221 			**
222 			**  If this is a configuration or local software
223 			**	error, send to the local postmaster as well,
224 			**	since the originator can't do anything
225 			**	about it anyway.  Note that this is a full
226 			**	copy of the message (intentionally) so that
227 			**	the Postmaster can forward things along.
228 			*/
229 
230 			if (ExitStat == EX_CONFIG || ExitStat == EX_SOFTWARE)
231 			{
232 				(void) sendtolist("postmaster",
233 					  NULLADDR, &e->e_errorqueue, e);
234 			}
235 			if (strcmp(e->e_from.q_paddr, "<>") != 0)
236 			{
237 				(void) sendtolist(e->e_from.q_paddr,
238 					  NULLADDR, &e->e_errorqueue, e);
239 			}
240 
241 			/*
242 			**  Deliver a non-delivery report to the
243 			**  Postmaster-designate (not necessarily
244 			**  Postmaster).  This does not include the
245 			**  body of the message, for privacy reasons.
246 			**  You really shouldn't need this.
247 			*/
248 
249 			e->e_flags |= EF_PM_NOTIFY;
250 
251 			/* check to see if there are any good addresses */
252 			for (q = e->e_errorqueue; q != NULL; q = q->q_next)
253 				if (!bitset(QBADADDR|QDONTSEND, q->q_flags))
254 					break;
255 			if (q == NULL)
256 			{
257 				/* this is an error-error */
258 				state = ESM_POSTMASTER;
259 				break;
260 			}
261 			if (returntosender(e->e_message, e->e_errorqueue,
262 					   (e->e_class >= 0), e) == 0)
263 			{
264 				state = ESM_DONE;
265 				break;
266 			}
267 
268 			/* didn't work -- return to postmaster */
269 			state = ESM_POSTMASTER;
270 			break;
271 
272 		  case ESM_POSTMASTER:
273 			/*
274 			**  Similar to previous case, but to system postmaster.
275 			*/
276 
277 			q = NULL;
278 			if (sendtolist("postmaster", NULL, &q, e) <= 0)
279 			{
280 				syserr("553 cannot parse postmaster!");
281 				ExitStat = EX_SOFTWARE;
282 				state = ESM_USRTMP;
283 				break;
284 			}
285 			if (returntosender(e->e_message,
286 					   q, (e->e_class >= 0), e) == 0)
287 			{
288 				state = ESM_DONE;
289 				break;
290 			}
291 
292 			/* didn't work -- last resort */
293 			state = ESM_USRTMP;
294 			break;
295 
296 		  case ESM_DEADLETTER:
297 			/*
298 			**  Save the message in dead.letter.
299 			**	If we weren't mailing back, and the user is
300 			**	local, we should save the message in
301 			**	~/dead.letter so that the poor person doesn't
302 			**	have to type it over again -- and we all know
303 			**	what poor typists UNIX users are.
304 			*/
305 
306 			p = NULL;
307 			if (e->e_from.q_mailer == LocalMailer)
308 			{
309 				if (e->e_from.q_home != NULL)
310 					p = e->e_from.q_home;
311 				else if ((pw = getpwnam(e->e_from.q_user)) != NULL)
312 					p = pw->pw_dir;
313 			}
314 			if (p == NULL)
315 			{
316 				/* no local directory */
317 				state = ESM_MAIL;
318 				break;
319 			}
320 			if (e->e_dfp != NULL)
321 			{
322 				bool oldverb = Verbose;
323 
324 				/* we have a home directory; open dead.letter */
325 				define('z', p, e);
326 				expand("\201z/dead.letter", buf, &buf[sizeof buf - 1], e);
327 				Verbose = TRUE;
328 				message("Saving message in %s", buf);
329 				Verbose = oldverb;
330 				e->e_to = buf;
331 				q = NULL;
332 				(void) sendtolist(buf, &e->e_from, &q, e);
333 				if (q != NULL &&
334 				    !bitset(QBADADDR, q->q_flags) &&
335 				    deliver(e, q) == 0)
336 					state = ESM_DONE;
337 				else
338 					state = ESM_MAIL;
339 			}
340 			else
341 			{
342 				/* no data file -- try mailing back */
343 				state = ESM_MAIL;
344 			}
345 			break;
346 
347 		  case ESM_USRTMP:
348 			/*
349 			**  Log the mail in /usr/tmp/dead.letter.
350 			*/
351 
352 			if (e->e_class < 0)
353 			{
354 				state = ESM_DONE;
355 				break;
356 			}
357 
358 			strcpy(buf, _PATH_VARTMP);
359 			strcat(buf, "dead.letter");
360 			if (!writable(buf, NULLADDR, SFF_NOSLINK))
361 			{
362 				state = ESM_PANIC;
363 				break;
364 			}
365 			fp = dfopen(buf, O_WRONLY|O_CREAT|O_APPEND, FileMode);
366 			if (fp == NULL)
367 			{
368 				state = ESM_PANIC;
369 				break;
370 			}
371 
372 			bzero(&mcibuf, sizeof mcibuf);
373 			mcibuf.mci_out = fp;
374 			mcibuf.mci_mailer = FileMailer;
375 			if (bitnset(M_7BITS, FileMailer->m_flags))
376 				mcibuf.mci_flags |= MCIF_7BIT;
377 
378 			putfromline(&mcibuf, e);
379 			(*e->e_puthdr)(&mcibuf, e);
380 			putline("\n", &mcibuf);
381 			(*e->e_putbody)(&mcibuf, e, NULL);
382 			putline("\n", &mcibuf);
383 			(void) fflush(fp);
384 			state = ferror(fp) ? ESM_PANIC : ESM_DONE;
385 			(void) xfclose(fp, "savemail", "/usr/tmp/dead.letter");
386 			break;
387 
388 		  default:
389 			syserr("554 savemail: unknown state %d", state);
390 
391 			/* fall through ... */
392 
393 		  case ESM_PANIC:
394 			/* leave the locked queue & transcript files around */
395 			syserr("!554 savemail: cannot save rejected email anywhere");
396 		}
397 	}
398 }
399 /*
400 **  RETURNTOSENDER -- return a message to the sender with an error.
401 **
402 **	Parameters:
403 **		msg -- the explanatory message.
404 **		returnq -- the queue of people to send the message to.
405 **		sendbody -- if TRUE, also send back the body of the
406 **			message; otherwise just send the header.
407 **		e -- the current envelope.
408 **
409 **	Returns:
410 **		zero -- if everything went ok.
411 **		else -- some error.
412 **
413 **	Side Effects:
414 **		Returns the current message to the sender via
415 **		mail.
416 */
417 
418 static bool	SendBody;
419 
420 #define MAXRETURNS	6	/* max depth of returning messages */
421 #define ERRORFUDGE	100	/* nominal size of error message text */
422 
423 returntosender(msg, returnq, sendbody, e)
424 	char *msg;
425 	ADDRESS *returnq;
426 	bool sendbody;
427 	register ENVELOPE *e;
428 {
429 	char buf[MAXNAME];
430 	extern putheader(), errbody();
431 	register ENVELOPE *ee;
432 	ENVELOPE *oldcur = CurEnv;
433 	ENVELOPE errenvelope;
434 	static int returndepth;
435 	register ADDRESS *q;
436 
437 	if (returnq == NULL)
438 		return (-1);
439 
440 	if (msg == NULL)
441 		msg = "Unable to deliver mail";
442 
443 	if (tTd(6, 1))
444 	{
445 		printf("Return To Sender: msg=\"%s\", depth=%d, e=%x, returnq=",
446 		       msg, returndepth, e);
447 		printaddr(returnq, TRUE);
448 	}
449 
450 	if (++returndepth >= MAXRETURNS)
451 	{
452 		if (returndepth != MAXRETURNS)
453 			syserr("554 returntosender: infinite recursion on %s", returnq->q_paddr);
454 		/* don't "unrecurse" and fake a clean exit */
455 		/* returndepth--; */
456 		return (0);
457 	}
458 
459 	SendBody = sendbody;
460 	define('g', e->e_from.q_paddr, e);
461 	define('u', NULL, e);
462 	ee = newenvelope(&errenvelope, e);
463 	define('a', "\201b", ee);
464 	define('r', "internal", ee);
465 	define('s', "localhost", ee);
466 	define('_', "localhost", ee);
467 	ee->e_puthdr = putheader;
468 	ee->e_putbody = errbody;
469 	ee->e_flags |= EF_RESPONSE|EF_METOO;
470 	if (!bitset(EF_OLDSTYLE, e->e_flags))
471 		ee->e_flags &= ~EF_OLDSTYLE;
472 	ee->e_sendqueue = returnq;
473 	ee->e_msgsize = ERRORFUDGE;
474 	if (!NoReturn)
475 		ee->e_msgsize += e->e_msgsize;
476 	initsys(ee);
477 	for (q = returnq; q != NULL; q = q->q_next)
478 	{
479 		if (bitset(QBADADDR, q->q_flags))
480 			continue;
481 
482 		if (!bitset(QDONTSEND, q->q_flags))
483 			ee->e_nrcpts++;
484 
485 		if (!DontPruneRoutes && pruneroute(q->q_paddr))
486 			parseaddr(q->q_paddr, q, RF_COPYPARSE, '\0', NULL, e);
487 
488 		if (q->q_alias == NULL)
489 			addheader("To", q->q_paddr, ee);
490 	}
491 
492 # ifdef LOG
493 	if (LogLevel > 5)
494 		syslog(LOG_INFO, "%s: %s: return to sender: %s",
495 			e->e_id, ee->e_id, msg);
496 # endif
497 
498 	if (strncmp(msg, "Warning:", 8) == 0 ||
499 	    strcmp(msg, "Return receipt") == 0)
500 	{
501 		addheader("Subject", msg, ee);
502 	}
503 	else
504 	{
505 		sprintf(buf, "Returned mail: %.*s", sizeof buf - 20, msg);
506 		addheader("Subject", buf, ee);
507 	}
508 	if (SendMIMEErrors)
509 	{
510 		addheader("MIME-Version", "1.0", ee);
511 		(void) sprintf(buf, "%s.%ld/%s",
512 			ee->e_id, curtime(), MyHostName);
513 		ee->e_msgboundary = newstr(buf);
514 		(void) sprintf(buf, "multipart/mixed; boundary=\"%s\"",
515 					ee->e_msgboundary);
516 		addheader("Content-Type", buf, ee);
517 	}
518 
519 	/* fake up an address header for the from person */
520 	expand("\201n", buf, &buf[sizeof buf - 1], e);
521 	if (parseaddr(buf, &ee->e_from, RF_COPYALL|RF_SENDERADDR, '\0', NULL, e) == NULL)
522 	{
523 		syserr("553 Can't parse myself!");
524 		ExitStat = EX_SOFTWARE;
525 		returndepth--;
526 		return (-1);
527 	}
528 	ee->e_sender = ee->e_from.q_paddr;
529 
530 	/* push state into submessage */
531 	CurEnv = ee;
532 	define('f', "\201n", ee);
533 	define('x', "Mail Delivery Subsystem", ee);
534 	eatheader(ee, TRUE);
535 
536 	/* mark statistics */
537 	markstats(ee, NULLADDR);
538 
539 	/* actually deliver the error message */
540 	sendall(ee, SM_DEFAULT);
541 
542 	/* restore state */
543 	dropenvelope(ee);
544 	CurEnv = oldcur;
545 	returndepth--;
546 
547 	/* should check for delivery errors here */
548 	return (0);
549 }
550 /*
551 **  ERRBODY -- output the body of an error message.
552 **
553 **	Typically this is a copy of the transcript plus a copy of the
554 **	original offending message.
555 **
556 **	Parameters:
557 **		mci -- the mailer connection information.
558 **		e -- the envelope we are working in.
559 **
560 **	Returns:
561 **		none
562 **
563 **	Side Effects:
564 **		Outputs the body of an error message.
565 */
566 
567 errbody(mci, e)
568 	register MCI *mci;
569 	register ENVELOPE *e;
570 {
571 	register FILE *xfile;
572 	char *p;
573 	register ADDRESS *q;
574 	bool printheader;
575 	char buf[MAXLINE];
576 
577 	if (e->e_parent == NULL)
578 	{
579 		syserr("errbody: null parent");
580 		putline("   ----- Original message lost -----\n", mci);
581 		return;
582 	}
583 
584 	/*
585 	**  Output MIME header.
586 	*/
587 
588 	if (e->e_msgboundary != NULL)
589 	{
590 		putline("This is a MIME-encapsulated message", mci);
591 		putline("", mci);
592 		(void) sprintf(buf, "--%s", e->e_msgboundary);
593 		putline(buf, mci);
594 		putline("", mci);
595 	}
596 
597 	/*
598 	**  Output introductory information.
599 	*/
600 
601 	for (q = e->e_parent->e_sendqueue; q != NULL; q = q->q_next)
602 		if (bitset(QBADADDR, q->q_flags))
603 			break;
604 	if (q == NULL &&
605 	    !bitset(EF_FATALERRS|EF_SENDRECEIPT, e->e_parent->e_flags))
606 	{
607 		putline("    **********************************************",
608 			mci);
609 		putline("    **      THIS IS A WARNING MESSAGE ONLY      **",
610 			mci);
611 		putline("    **  YOU DO NOT NEED TO RESEND YOUR MESSAGE  **",
612 			mci);
613 		putline("    **********************************************",
614 			mci);
615 		putline("", mci);
616 	}
617 	sprintf(buf, "The original message was received at %s",
618 		arpadate(ctime(&e->e_parent->e_ctime)));
619 	putline(buf, mci);
620 	expand("from \201_", buf, &buf[sizeof buf - 1], e->e_parent);
621 	putline(buf, mci);
622 	putline("", mci);
623 
624 	/*
625 	**  Output error message header (if specified and available).
626 	*/
627 
628 	if (ErrMsgFile != NULL)
629 	{
630 		if (*ErrMsgFile == '/')
631 		{
632 			xfile = fopen(ErrMsgFile, "r");
633 			if (xfile != NULL)
634 			{
635 				while (fgets(buf, sizeof buf, xfile) != NULL)
636 				{
637 					expand(buf, buf, &buf[sizeof buf - 1], e);
638 					putline(buf, mci);
639 				}
640 				(void) fclose(xfile);
641 				putline("\n", mci);
642 			}
643 		}
644 		else
645 		{
646 			expand(ErrMsgFile, buf, &buf[sizeof buf - 1], e);
647 			putline(buf, mci);
648 			putline("", mci);
649 		}
650 	}
651 
652 	/*
653 	**  Output message introduction
654 	*/
655 
656 	printheader = TRUE;
657 	for (q = e->e_parent->e_sendqueue; q != NULL; q = q->q_next)
658 	{
659 		if (bitset(QBADADDR|QREPORT, q->q_flags))
660 		{
661 			if (printheader)
662 			{
663 				putline("   ----- The following addresses had delivery problems -----",
664 					mci);
665 				printheader = FALSE;
666 			}
667 			strcpy(buf, q->q_paddr);
668 			if (bitset(QBADADDR, q->q_flags))
669 				strcat(buf, "  (unrecoverable error)");
670 			else
671 				strcat(buf, "  (transient failure)");
672 			putline(buf, mci);
673 			if (q->q_alias != NULL)
674 			{
675 				strcpy(buf, "    (expanded from: ");
676 				strcat(buf, q->q_alias->q_paddr);
677 				strcat(buf, ")");
678 				putline(buf, mci);
679 			}
680 		}
681 	}
682 	if (!printheader)
683 		putline("\n", mci);
684 
685 	/*
686 	**  Output transcript of errors
687 	*/
688 
689 	(void) fflush(stdout);
690 	p = queuename(e->e_parent, 'x');
691 	if ((xfile = fopen(p, "r")) == NULL)
692 	{
693 		syserr("Cannot open %s", p);
694 		putline("   ----- Transcript of session is unavailable -----\n", mci);
695 	}
696 	else
697 	{
698 		putline("   ----- Transcript of session follows -----\n", mci);
699 		if (e->e_xfp != NULL)
700 			(void) fflush(e->e_xfp);
701 		while (fgets(buf, sizeof buf, xfile) != NULL)
702 			putline(buf, mci);
703 		(void) xfclose(xfile, "errbody xscript", p);
704 	}
705 	errno = 0;
706 
707 	/*
708 	**  Output text of original message
709 	*/
710 
711 	if (NoReturn)
712 		SendBody = FALSE;
713 	putline("", mci);
714 	if (e->e_parent->e_df != NULL)
715 	{
716 		if (SendBody)
717 			putline("   ----- Original message follows -----\n", mci);
718 		else
719 			putline("   ----- Message header follows -----\n", mci);
720 		(void) fflush(mci->mci_out);
721 
722 		if (e->e_msgboundary != NULL)
723 		{
724 			putline("", mci);
725 			(void) sprintf(buf, "--%s", e->e_msgboundary);
726 			putline(buf, mci);
727 			putline("Content-Type: message/rfc822", mci);
728 			putline("", mci);
729 		}
730 		putheader(mci, e->e_parent);
731 		putline("", mci);
732 		if (SendBody)
733 			putbody(mci, e->e_parent, e->e_msgboundary);
734 		else
735 			putline("   ----- Message body suppressed -----", mci);
736 	}
737 	else
738 	{
739 		putline("  ----- No message was collected -----\n", mci);
740 	}
741 
742 	if (e->e_msgboundary != NULL)
743 	{
744 		putline("", mci);
745 		(void) sprintf(buf, "--%s--", e->e_msgboundary);
746 		putline(buf, mci);
747 	}
748 	putline("", mci);
749 
750 	/*
751 	**  Cleanup and exit
752 	*/
753 
754 	if (errno != 0)
755 		syserr("errbody: I/O error");
756 }
757 /*
758 **  PRUNEROUTE -- prune an RFC-822 source route
759 **
760 **	Trims down a source route to the last internet-registered hop.
761 **	This is encouraged by RFC 1123 section 5.3.3.
762 **
763 **	Parameters:
764 **		addr -- the address
765 **
766 **	Returns:
767 **		TRUE -- address was modified
768 **		FALSE -- address could not be pruned
769 **
770 **	Side Effects:
771 **		modifies addr in-place
772 */
773 
774 pruneroute(addr)
775 	char *addr;
776 {
777 #if NAMED_BIND
778 	char *start, *at, *comma;
779 	char c;
780 	int rcode;
781 	char hostbuf[BUFSIZ];
782 	char *mxhosts[MAXMXHOSTS + 1];
783 
784 	/* check to see if this is really a route-addr */
785 	if (*addr != '<' || addr[1] != '@' || addr[strlen(addr) - 1] != '>')
786 		return FALSE;
787 	start = strchr(addr, ':');
788 	at = strrchr(addr, '@');
789 	if (start == NULL || at == NULL || at < start)
790 		return FALSE;
791 
792 	/* slice off the angle brackets */
793 	strcpy(hostbuf, at + 1);
794 	hostbuf[strlen(hostbuf) - 1] = '\0';
795 
796 	while (start)
797 	{
798 		if (getmxrr(hostbuf, mxhosts, FALSE, &rcode) > 0)
799 		{
800 			strcpy(addr + 1, start + 1);
801 			return TRUE;
802 		}
803 		c = *start;
804 		*start = '\0';
805 		comma = strrchr(addr, ',');
806 		if (comma && comma[1] == '@')
807 			strcpy(hostbuf, comma + 2);
808 		else
809 			comma = 0;
810 		*start = c;
811 		start = comma;
812 	}
813 #endif
814 	return FALSE;
815 }
816