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[] = "@(#)savemail.c	6.15 (Berkeley) 02/28/93";
11 #endif /* not lint */
12 
13 # include <sys/types.h>
14 # include <pwd.h>
15 # include "sendmail.h"
16 
17 /*
18 **  SAVEMAIL -- Save mail on error
19 **
20 **	If mailing back errors, mail it back to the originator
21 **	together with an error message; otherwise, just put it in
22 **	dead.letter in the user's home directory (if he exists on
23 **	this machine).
24 **
25 **	Parameters:
26 **		e -- the envelope containing the message in error.
27 **
28 **	Returns:
29 **		none
30 **
31 **	Side Effects:
32 **		Saves the letter, by writing or mailing it back to the
33 **		sender, or by putting it in dead.letter in her home
34 **		directory.
35 */
36 
37 /* defines for state machine */
38 # define ESM_REPORT	0	/* report to sender's terminal */
39 # define ESM_MAIL	1	/* mail back to sender */
40 # define ESM_QUIET	2	/* messages have already been returned */
41 # define ESM_DEADLETTER	3	/* save in ~/dead.letter */
42 # define ESM_POSTMASTER	4	/* return to postmaster */
43 # define ESM_USRTMP	5	/* save in /usr/tmp/dead.letter */
44 # define ESM_PANIC	6	/* leave the locked queue/transcript files */
45 # define ESM_DONE	7	/* the message is successfully delivered */
46 
47 
48 savemail(e)
49 	register ENVELOPE *e;
50 {
51 	register struct passwd *pw;
52 	register FILE *fp;
53 	int state;
54 	auto ADDRESS *q;
55 	char buf[MAXLINE+1];
56 	extern struct passwd *getpwnam();
57 	register char *p;
58 	extern char *ttypath();
59 	typedef int (*fnptr)();
60 
61 	if (tTd(6, 1))
62 		printf("\nsavemail, ErrorMode = %c\n", ErrorMode);
63 
64 	if (bitset(EF_RESPONSE, e->e_flags))
65 		return;
66 	e->e_flags &= ~EF_FATALERRS;
67 
68 	/*
69 	**  In the unhappy event we don't know who to return the mail
70 	**  to, make someone up.
71 	*/
72 
73 	if (e->e_from.q_paddr == NULL)
74 	{
75 		if (parseaddr("root", &e->e_from, 0, '\0', e) == NULL)
76 		{
77 			syserr("553 Cannot parse root!");
78 			ExitStat = EX_SOFTWARE;
79 			finis();
80 		}
81 	}
82 	e->e_to = NULL;
83 
84 	/*
85 	**  Basic state machine.
86 	**
87 	**	This machine runs through the following states:
88 	**
89 	**	ESM_QUIET	Errors have already been printed iff the
90 	**			sender is local.
91 	**	ESM_REPORT	Report directly to the sender's terminal.
92 	**	ESM_MAIL	Mail response to the sender.
93 	**	ESM_DEADLETTER	Save response in ~/dead.letter.
94 	**	ESM_POSTMASTER	Mail response to the postmaster.
95 	**	ESM_PANIC	Save response anywhere possible.
96 	*/
97 
98 	/* determine starting state */
99 	switch (ErrorMode)
100 	{
101 	  case EM_WRITE:
102 		state = ESM_REPORT;
103 		break;
104 
105 	  case EM_BERKNET:
106 		/* mail back, but return o.k. exit status */
107 		ExitStat = EX_OK;
108 
109 		/* fall through.... */
110 
111 	  case EM_MAIL:
112 		state = ESM_MAIL;
113 		break;
114 
115 	  case EM_PRINT:
116 	  case '\0':
117 		state = ESM_QUIET;
118 		break;
119 
120 	  case EM_QUIET:
121 		/* no need to return anything at all */
122 		return;
123 
124 	  default:
125 		syserr("554 savemail: ErrorMode x%x\n");
126 		state = ESM_MAIL;
127 		break;
128 	}
129 
130 	while (state != ESM_DONE)
131 	{
132 		if (tTd(6, 5))
133 			printf("  state %d\n", state);
134 
135 		switch (state)
136 		{
137 		  case ESM_QUIET:
138 			if (e->e_from.q_mailer == LocalMailer)
139 				state = ESM_DEADLETTER;
140 			else
141 				state = ESM_MAIL;
142 			break;
143 
144 		  case ESM_REPORT:
145 
146 			/*
147 			**  If the user is still logged in on the same terminal,
148 			**  then write the error messages back to hir (sic).
149 			*/
150 
151 			p = ttypath();
152 			if (p == NULL || freopen(p, "w", stdout) == NULL)
153 			{
154 				state = ESM_MAIL;
155 				break;
156 			}
157 
158 			expand("\201n", buf, &buf[sizeof buf - 1], e);
159 			printf("\r\nMessage from %s...\r\n", buf);
160 			printf("Errors occurred while sending mail.\r\n");
161 			if (e->e_xfp != NULL)
162 			{
163 				(void) fflush(e->e_xfp);
164 				fp = fopen(queuename(e, 'x'), "r");
165 			}
166 			else
167 				fp = NULL;
168 			if (fp == NULL)
169 			{
170 				syserr("Cannot open %s", queuename(e, 'x'));
171 				printf("Transcript of session is unavailable.\r\n");
172 			}
173 			else
174 			{
175 				printf("Transcript follows:\r\n");
176 				while (fgets(buf, sizeof buf, fp) != NULL &&
177 				       !ferror(stdout))
178 					fputs(buf, stdout);
179 				(void) fclose(fp);
180 			}
181 			printf("Original message will be saved in dead.letter.\r\n");
182 			state = ESM_DEADLETTER;
183 			break;
184 
185 		  case ESM_MAIL:
186 		  case ESM_POSTMASTER:
187 			/*
188 			**  If mailing back, do it.
189 			**	Throw away all further output.  Don't alias,
190 			**	since this could cause loops, e.g., if joe
191 			**	mails to joe@x, and for some reason the network
192 			**	for @x is down, then the response gets sent to
193 			**	joe@x, which gives a response, etc.  Also force
194 			**	the mail to be delivered even if a version of
195 			**	it has already been sent to the sender.
196 			**
197 			**	Clever technique for computing rpath from
198 			**	Eric Wassenaar <e07@nikhef.nl>.
199 			*/
200 
201 			if (state == ESM_MAIL)
202 			{
203 				char *rpath;
204 
205 				if (e->e_returnpath != e->e_sender)
206 					rpath = e->e_returnpath;
207 				else
208 					rpath = e->e_from.q_paddr;
209 				if (strcmp(rpath, "<>") != 0)
210 					(void) sendtolist(rpath,
211 						  (ADDRESS *) NULL,
212 						  &e->e_errorqueue, e);
213 
214 				/* deliver a cc: to the postmaster if desired */
215 				if (PostMasterCopy != NULL)
216 					(void) sendtolist(PostMasterCopy,
217 							  (ADDRESS *) NULL,
218 							  &e->e_errorqueue, e);
219 				q = e->e_errorqueue;
220 				if (q == NULL)
221 				{
222 					/* this is an error-error */
223 					state = ESM_USRTMP;
224 					break;
225 				}
226 			}
227 			else
228 			{
229 				if (parseaddr("postmaster", q, 0, '\0', e) == NULL)
230 				{
231 					syserr("553 cannot parse postmaster!");
232 					ExitStat = EX_SOFTWARE;
233 					state = ESM_USRTMP;
234 					break;
235 				}
236 			}
237 			if (returntosender(e->e_message != NULL ? e->e_message :
238 					   "Unable to deliver mail",
239 					   q, (e->e_class >= 0), e) == 0)
240 			{
241 				state = ESM_DONE;
242 				break;
243 			}
244 
245 			state = state == ESM_MAIL ? ESM_POSTMASTER : ESM_USRTMP;
246 			break;
247 
248 		  case ESM_DEADLETTER:
249 			/*
250 			**  Save the message in dead.letter.
251 			**	If we weren't mailing back, and the user is
252 			**	local, we should save the message in
253 			**	~/dead.letter so that the poor person doesn't
254 			**	have to type it over again -- and we all know
255 			**	what poor typists UNIX users are.
256 			*/
257 
258 			p = NULL;
259 			if (e->e_from.q_mailer == LocalMailer)
260 			{
261 				if (e->e_from.q_home != NULL)
262 					p = e->e_from.q_home;
263 				else if ((pw = getpwnam(e->e_from.q_user)) != NULL)
264 					p = pw->pw_dir;
265 			}
266 			if (p == NULL)
267 			{
268 				syserr("554 Can't return mail to %s", e->e_from.q_paddr);
269 				state = ESM_MAIL;
270 				break;
271 			}
272 			if (e->e_dfp != NULL)
273 			{
274 				auto ADDRESS *q;
275 				bool oldverb = Verbose;
276 
277 				/* we have a home directory; open dead.letter */
278 				define('z', p, e);
279 				expand("\201z/dead.letter", buf, &buf[sizeof buf - 1], e);
280 				Verbose = TRUE;
281 				message("Saving message in %s", buf);
282 				Verbose = oldverb;
283 				e->e_to = buf;
284 				q = NULL;
285 				(void) sendtolist(buf, &e->e_from, &q, e);
286 				if (deliver(e, q) == 0)
287 					state = ESM_DONE;
288 				else
289 					state = ESM_MAIL;
290 			}
291 			else
292 			{
293 				/* no data file -- try mailing back */
294 				state = ESM_MAIL;
295 			}
296 			break;
297 
298 		  case ESM_USRTMP:
299 			/*
300 			**  Log the mail in /usr/tmp/dead.letter.
301 			*/
302 
303 			if (e->e_class < 0)
304 			{
305 				state = ESM_DONE;
306 				break;
307 			}
308 
309 			fp = dfopen("/usr/tmp/dead.letter", "a");
310 			if (fp == NULL)
311 			{
312 				state = ESM_PANIC;
313 				break;
314 			}
315 
316 			putfromline(fp, FileMailer, e);
317 			(*e->e_puthdr)(fp, FileMailer, e);
318 			putline("\n", fp, FileMailer);
319 			(*e->e_putbody)(fp, FileMailer, e);
320 			putline("\n", fp, FileMailer);
321 			(void) fflush(fp);
322 			state = ferror(fp) ? ESM_PANIC : ESM_DONE;
323 			(void) fclose(fp);
324 			break;
325 
326 		  default:
327 			syserr("554 savemail: unknown state %d", state);
328 
329 			/* fall through ... */
330 
331 		  case ESM_PANIC:
332 			/* leave the locked queue & transcript files around */
333 			syserr("554 savemail: cannot save rejected email anywhere");
334 			exit(EX_SOFTWARE);
335 		}
336 	}
337 }
338 /*
339 **  RETURNTOSENDER -- return a message to the sender with an error.
340 **
341 **	Parameters:
342 **		msg -- the explanatory message.
343 **		returnq -- the queue of people to send the message to.
344 **		sendbody -- if TRUE, also send back the body of the
345 **			message; otherwise just send the header.
346 **		e -- the current envelope.
347 **
348 **	Returns:
349 **		zero -- if everything went ok.
350 **		else -- some error.
351 **
352 **	Side Effects:
353 **		Returns the current message to the sender via
354 **		mail.
355 */
356 
357 static bool	SendBody;
358 
359 #define MAXRETURNS	6	/* max depth of returning messages */
360 
361 returntosender(msg, returnq, sendbody, e)
362 	char *msg;
363 	ADDRESS *returnq;
364 	bool sendbody;
365 	register ENVELOPE *e;
366 {
367 	char buf[MAXNAME];
368 	extern putheader(), errbody();
369 	register ENVELOPE *ee;
370 	extern ENVELOPE *newenvelope();
371 	ENVELOPE errenvelope;
372 	static int returndepth;
373 	register ADDRESS *q;
374 
375 	if (tTd(6, 1))
376 	{
377 		printf("Return To Sender: msg=\"%s\", depth=%d, e=%x,\n",
378 		       msg, returndepth, e);
379 		printf("\treturnq=");
380 		printaddr(returnq, TRUE);
381 	}
382 
383 	if (++returndepth >= MAXRETURNS)
384 	{
385 		if (returndepth != MAXRETURNS)
386 			syserr("554 returntosender: infinite recursion on %s", returnq->q_paddr);
387 		/* don't "unrecurse" and fake a clean exit */
388 		/* returndepth--; */
389 		return (0);
390 	}
391 
392 	SendBody = sendbody;
393 	define('g', e->e_sender, e);
394 	define('<', e->e_returnpath, e);
395 	ee = newenvelope(&errenvelope, e);
396 	define('a', "\201b", ee);
397 	ee->e_puthdr = putheader;
398 	ee->e_putbody = errbody;
399 	ee->e_flags |= EF_RESPONSE;
400 	if (!bitset(EF_OLDSTYLE, e->e_flags))
401 		ee->e_flags &= ~EF_OLDSTYLE;
402 	ee->e_sendqueue = returnq;
403 	openxscript(ee);
404 	for (q = returnq; q != NULL; q = q->q_next)
405 	{
406 		if (!DontPruneRoutes && pruneroute(q->q_paddr))
407 			parseaddr(q->q_paddr, q, 0, '\0', e);
408 
409 		if (q->q_alias == NULL)
410 			addheader("to", q->q_paddr, ee);
411 	}
412 
413 # ifdef LOG
414 	if (LogLevel > 5)
415 		syslog(LOG_INFO, "%s: %s: return to sender: %s",
416 			e->e_id, ee->e_id, msg);
417 # endif
418 
419 	(void) sprintf(buf, "Returned mail: %s", msg);
420 	addheader("subject", buf, ee);
421 
422 	/* fake up an address header for the from person */
423 	expand("\201n", buf, &buf[sizeof buf - 1], e);
424 	ee->e_sender = newstr(buf);
425 	if (ConfigLevel >= 4)
426 		ee->e_returnpath = "<>";
427 	else
428 		ee->e_returnpath = ee->e_sender;
429 	if (parseaddr(buf, &ee->e_from, -1, '\0', e) == NULL)
430 	{
431 		syserr("553 Can't parse myself!");
432 		ExitStat = EX_SOFTWARE;
433 		returndepth--;
434 		return (-1);
435 	}
436 	loweraddr(&ee->e_from);
437 
438 	/* push state into submessage */
439 	CurEnv = ee;
440 	define('f', "\201n", ee);
441 	define('x', "Mail Delivery Subsystem", ee);
442 	eatheader(ee, FALSE);
443 
444 	/* actually deliver the error message */
445 	sendall(ee, SM_DEFAULT);
446 
447 	/* restore state */
448 	dropenvelope(ee);
449 	CurEnv = CurEnv->e_parent;
450 	returndepth--;
451 
452 	/* should check for delivery errors here */
453 	return (0);
454 }
455 /*
456 **  ERRBODY -- output the body of an error message.
457 **
458 **	Typically this is a copy of the transcript plus a copy of the
459 **	original offending message.
460 **
461 **	Parameters:
462 **		fp -- the output file.
463 **		m -- the mailer to output to.
464 **		e -- the envelope we are working in.
465 **
466 **	Returns:
467 **		none
468 **
469 **	Side Effects:
470 **		Outputs the body of an error message.
471 */
472 
473 errbody(fp, m, e)
474 	register FILE *fp;
475 	register struct mailer *m;
476 	register ENVELOPE *e;
477 {
478 	register FILE *xfile;
479 	char buf[MAXLINE];
480 	char *p;
481 
482 	/*
483 	**  Output error message header (if specified and available).
484 	*/
485 
486 	if (ErrMsgFile != NULL)
487 	{
488 		if (*ErrMsgFile == '/')
489 		{
490 			xfile = fopen(ErrMsgFile, "r");
491 			if (xfile != NULL)
492 			{
493 				while (fgets(buf, sizeof buf, xfile) != NULL)
494 				{
495 					expand(buf, buf, &buf[sizeof buf - 1], e);
496 					putline(buf, fp, m);
497 				}
498 				(void) fclose(xfile);
499 				fprintf(fp, "\n");
500 			}
501 		}
502 		else
503 		{
504 			expand(ErrMsgFile, buf, &buf[sizeof buf - 1], e);
505 			putline(buf, fp, m);
506 			fprintf(fp, "\n");
507 		}
508 	}
509 
510 	/*
511 	**  Output transcript of errors
512 	*/
513 
514 	(void) fflush(stdout);
515 	p = queuename(e->e_parent, 'x');
516 	if ((xfile = fopen(p, "r")) == NULL)
517 	{
518 		syserr("Cannot open %s", p);
519 		fprintf(fp, "  ----- Transcript of session is unavailable -----\n");
520 	}
521 	else
522 	{
523 		fprintf(fp, "   ----- Transcript of session follows -----\n");
524 		if (e->e_xfp != NULL)
525 			(void) fflush(e->e_xfp);
526 		while (fgets(buf, sizeof buf, xfile) != NULL)
527 			putline(buf, fp, m);
528 		(void) fclose(xfile);
529 	}
530 	errno = 0;
531 
532 	/*
533 	**  Output text of original message
534 	*/
535 
536 	if (NoReturn)
537 		fprintf(fp, "\n   ----- Return message suppressed -----\n\n");
538 	else if (e->e_parent->e_dfp != NULL)
539 	{
540 		if (SendBody)
541 		{
542 			putline("\n", fp, m);
543 			putline("   ----- Unsent message follows -----\n", fp, m);
544 			(void) fflush(fp);
545 			putheader(fp, m, e->e_parent);
546 			putline("\n", fp, m);
547 			putbody(fp, m, e->e_parent);
548 		}
549 		else
550 		{
551 			putline("\n", fp, m);
552 			putline("  ----- Message header follows -----\n", fp, m);
553 			(void) fflush(fp);
554 			putheader(fp, m, e->e_parent);
555 		}
556 	}
557 	else
558 	{
559 		putline("\n", fp, m);
560 		putline("  ----- No message was collected -----\n", fp, m);
561 		putline("\n", fp, m);
562 	}
563 
564 	/*
565 	**  Cleanup and exit
566 	*/
567 
568 	if (errno != 0)
569 		syserr("errbody: I/O error");
570 }
571 /*
572 **  PRUNEROUTE -- prune an RFC-822 source route
573 **
574 **	Trims down a source route to the last internet-registered hop.
575 **	This is encouraged by RFC 1123 section 5.3.3.
576 **
577 **	Parameters:
578 **		addr -- the address
579 **
580 **	Returns:
581 **		TRUE -- address was modified
582 **		FALSE -- address could not be pruned
583 **
584 **	Side Effects:
585 **		modifies addr in-place
586 */
587 
588 pruneroute(addr)
589 	char *addr;
590 {
591 #ifdef NAMED_BIND
592 	char *start, *at, *comma;
593 	char c;
594 	int rcode;
595 	char hostbuf[BUFSIZ];
596 	char *mxhosts[MAXMXHOSTS + 1];
597 
598 	/* check to see if this is really a route-addr */
599 	if (*addr != '<' || addr[1] != '@' || addr[strlen(addr) - 1] != '>')
600 		return FALSE;
601 	start = strchr(addr, ':');
602 	at = strrchr(addr, '@');
603 	if (start == NULL || at == NULL || at < start)
604 		return FALSE;
605 
606 	/* slice off the angle brackets */
607 	strcpy(hostbuf, at + 1);
608 	hostbuf[strlen(hostbuf) - 1] = '\0';
609 
610 	while (start)
611 	{
612 		if (getmxrr(hostbuf, mxhosts, "", &rcode) > 0)
613 		{
614 			strcpy(addr + 1, start + 1);
615 			return TRUE;
616 		}
617 		c = *start;
618 		*start = '\0';
619 		comma = strrchr(addr, ',');
620 		if (comma && comma[1] == '@')
621 			strcpy(hostbuf, comma + 2);
622 		else
623 			comma = 0;
624 		*start = c;
625 		start = comma;
626 	}
627 #endif
628 	return FALSE;
629 }
630