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[] = "@(#)parseaddr.c	5.25 (Berkeley) 11/14/92";
11 #endif /* not lint */
12 
13 # include "sendmail.h"
14 
15 /*
16 **  PARSEADDR -- Parse an address
17 **
18 **	Parses an address and breaks it up into three parts: a
19 **	net to transmit the message on, the host to transmit it
20 **	to, and a user on that host.  These are loaded into an
21 **	ADDRESS header with the values squirreled away if necessary.
22 **	The "user" part may not be a real user; the process may
23 **	just reoccur on that machine.  For example, on a machine
24 **	with an arpanet connection, the address
25 **		csvax.bill@berkeley
26 **	will break up to a "user" of 'csvax.bill' and a host
27 **	of 'berkeley' -- to be transmitted over the arpanet.
28 **
29 **	Parameters:
30 **		addr -- the address to parse.
31 **		a -- a pointer to the address descriptor buffer.
32 **			If NULL, a header will be created.
33 **		copyf -- determines what shall be copied:
34 **			-1 -- don't copy anything.  The printname
35 **				(q_paddr) is just addr, and the
36 **				user & host are allocated internally
37 **				to parse.
38 **			0 -- copy out the parsed user & host, but
39 **				don't copy the printname.
40 **			+1 -- copy everything.
41 **		delim -- the character to terminate the address, passed
42 **			to prescan.
43 **		e -- the envelope that will contain this address.
44 **
45 **	Returns:
46 **		A pointer to the address descriptor header (`a' if
47 **			`a' is non-NULL).
48 **		NULL on error.
49 **
50 **	Side Effects:
51 **		none
52 */
53 
54 /* following delimiters are inherent to the internal algorithms */
55 # define DELIMCHARS	"\001()<>,;\\\"\r\n"	/* word delimiters */
56 
57 ADDRESS *
58 parseaddr(addr, a, copyf, delim, e)
59 	char *addr;
60 	register ADDRESS *a;
61 	int copyf;
62 	char delim;
63 	register ENVELOPE *e;
64 {
65 	register char **pvp;
66 	char pvpbuf[PSBUFSIZE];
67 	extern char **prescan();
68 	extern ADDRESS *buildaddr();
69 
70 	/*
71 	**  Initialize and prescan address.
72 	*/
73 
74 	e->e_to = addr;
75 	if (tTd(20, 1))
76 		printf("\n--parseaddr(%s)\n", addr);
77 
78 	pvp = prescan(addr, delim, pvpbuf);
79 	if (pvp == NULL)
80 	{
81 		if (tTd(20, 1))
82 			printf("parseaddr-->NULL\n");
83 		return (NULL);
84 	}
85 
86 	/*
87 	**  Apply rewriting rules.
88 	**	Ruleset 0 does basic parsing.  It must resolve.
89 	*/
90 
91 	rewrite(pvp, 3);
92 	rewrite(pvp, 0);
93 
94 	/*
95 	**  See if we resolved to a real mailer.
96 	*/
97 
98 	if (pvp[0][0] != CANONNET)
99 	{
100 		setstat(EX_USAGE);
101 		usrerr("cannot resolve name");
102 		return (NULL);
103 	}
104 
105 	/*
106 	**  Build canonical address from pvp.
107 	*/
108 
109 	a = buildaddr(pvp, a);
110 	if (a == NULL)
111 		return (NULL);
112 
113 	/*
114 	**  Make local copies of the host & user and then
115 	**  transport them out.
116 	*/
117 
118 	allocaddr(a, copyf, addr);
119 
120 	/*
121 	**  Compute return value.
122 	*/
123 
124 	if (tTd(20, 1))
125 	{
126 		printf("parseaddr-->");
127 		printaddr(a, FALSE);
128 	}
129 
130 	return (a);
131 }
132 /*
133 **  ALLOCADDR -- do local allocations of address on demand.
134 **
135 **	Also lowercases the host name if requested.
136 **
137 **	Parameters:
138 **		a -- the address to reallocate.
139 **		copyf -- the copy flag (see parseaddr for description).
140 **		paddr -- the printname of the address.
141 **
142 **	Returns:
143 **		none.
144 **
145 **	Side Effects:
146 **		Copies portions of a into local buffers as requested.
147 */
148 
149 allocaddr(a, copyf, paddr)
150 	register ADDRESS *a;
151 	int copyf;
152 	char *paddr;
153 {
154 	register MAILER *m = a->q_mailer;
155 
156 	if (copyf > 0 && paddr != NULL)
157 	{
158 		extern char *DelimChar;
159 		char savec = *DelimChar;
160 
161 		*DelimChar = '\0';
162 		a->q_paddr = newstr(paddr);
163 		*DelimChar = savec;
164 	}
165 	else
166 		a->q_paddr = paddr;
167 
168 	if (a->q_user == NULL)
169 		a->q_user = "";
170 	if (a->q_host == NULL)
171 		a->q_host = "";
172 
173 	if (copyf >= 0)
174 	{
175 		a->q_host = newstr(a->q_host);
176 		if (a->q_user != a->q_paddr)
177 			a->q_user = newstr(a->q_user);
178 	}
179 
180 	if (a->q_paddr == NULL)
181 		a->q_paddr = a->q_user;
182 
183 	/*
184 	**  Convert host name to lower case if requested.
185 	**	User name will be done later.
186 	*/
187 
188 	if (!bitnset(M_HST_UPPER, m->m_flags))
189 		makelower(a->q_host);
190 }
191 /*
192 **  LOWERADDR -- map UPPER->lower case on addresses as requested.
193 **
194 **	Parameters:
195 **		a -- address to be mapped.
196 **
197 **	Returns:
198 **		none.
199 **
200 **	Side Effects:
201 **		none.
202 */
203 
204 loweraddr(a)
205 	register ADDRESS *a;
206 {
207 	register MAILER *m = a->q_mailer;
208 
209 	if (!bitnset(M_USR_UPPER, m->m_flags))
210 		makelower(a->q_user);
211 }
212 /*
213 **  PRESCAN -- Prescan name and make it canonical
214 **
215 **	Scans a name and turns it into a set of tokens.  This process
216 **	deletes blanks and comments (in parentheses).
217 **
218 **	This routine knows about quoted strings and angle brackets.
219 **
220 **	There are certain subtleties to this routine.  The one that
221 **	comes to mind now is that backslashes on the ends of names
222 **	are silently stripped off; this is intentional.  The problem
223 **	is that some versions of sndmsg (like at LBL) set the kill
224 **	character to something other than @ when reading addresses;
225 **	so people type "csvax.eric\@berkeley" -- which screws up the
226 **	berknet mailer.
227 **
228 **	Parameters:
229 **		addr -- the name to chomp.
230 **		delim -- the delimiter for the address, normally
231 **			'\0' or ','; \0 is accepted in any case.
232 **			If '\t' then we are reading the .cf file.
233 **		pvpbuf -- place to put the saved text -- note that
234 **			the pointers are static.
235 **
236 **	Returns:
237 **		A pointer to a vector of tokens.
238 **		NULL on error.
239 **
240 **	Side Effects:
241 **		sets DelimChar to point to the character matching 'delim'.
242 */
243 
244 /* states and character types */
245 # define OPR		0	/* operator */
246 # define ATM		1	/* atom */
247 # define QST		2	/* in quoted string */
248 # define SPC		3	/* chewing up spaces */
249 # define ONE		4	/* pick up one character */
250 
251 # define NSTATES	5	/* number of states */
252 # define TYPE		017	/* mask to select state type */
253 
254 /* meta bits for table */
255 # define M		020	/* meta character; don't pass through */
256 # define B		040	/* cause a break */
257 # define MB		M|B	/* meta-break */
258 
259 static short StateTab[NSTATES][NSTATES] =
260 {
261    /*	oldst	chtype>	OPR	ATM	QST	SPC	ONE	*/
262 	/*OPR*/		OPR|B,	ATM|B,	QST|B,	SPC|MB,	ONE|B,
263 	/*ATM*/		OPR|B,	ATM,	QST|B,	SPC|MB,	ONE|B,
264 	/*QST*/		QST,	QST,	OPR,	QST,	QST,
265 	/*SPC*/		OPR,	ATM,	QST,	SPC|M,	ONE,
266 	/*ONE*/		OPR,	OPR,	OPR,	OPR,	OPR,
267 };
268 
269 # define NOCHAR		-1	/* signal nothing in lookahead token */
270 
271 char	*DelimChar;		/* set to point to the delimiter */
272 
273 char **
274 prescan(addr, delim, pvpbuf)
275 	char *addr;
276 	char delim;
277 	char pvpbuf[];
278 {
279 	register char *p;
280 	register char *q;
281 	register int c;
282 	char **avp;
283 	bool bslashmode;
284 	int cmntcnt;
285 	int anglecnt;
286 	char *tok;
287 	int state;
288 	int newstate;
289 	static char *av[MAXATOM+1];
290 	extern int errno;
291 
292 	/* make sure error messages don't have garbage on them */
293 	errno = 0;
294 
295 	q = pvpbuf;
296 	bslashmode = FALSE;
297 	cmntcnt = 0;
298 	anglecnt = 0;
299 	avp = av;
300 	state = ATM;
301 	c = NOCHAR;
302 	p = addr;
303 	if (tTd(22, 11))
304 	{
305 		printf("prescan: ");
306 		xputs(p);
307 		(void) putchar('\n');
308 	}
309 
310 	do
311 	{
312 		/* read a token */
313 		tok = q;
314 		for (;;)
315 		{
316 			/* store away any old lookahead character */
317 			if (c != NOCHAR)
318 			{
319 				/* see if there is room */
320 				if (q >= &pvpbuf[PSBUFSIZE - 5])
321 				{
322 					usrerr("Address too long");
323 					DelimChar = p;
324 					return (NULL);
325 				}
326 
327 				/* squirrel it away */
328 				*q++ = c;
329 			}
330 
331 			/* read a new input character */
332 			c = *p++;
333 			if (c == '\0' || (c == delim && anglecnt <= 0))
334 			{
335 				/* diagnose and patch up bad syntax */
336 				if (state == QST)
337 				{
338 					usrerr("Unbalanced '\"'");
339 					c = '"';
340 				}
341 				else if (cmntcnt > 0)
342 				{
343 					usrerr("Unbalanced '('");
344 					c = ')';
345 				}
346 				else if (anglecnt > 0)
347 				{
348 					c = '>';
349 					usrerr("Unbalanced '<'");
350 				}
351 				else
352 					break;
353 
354 				p--;
355 			}
356 
357 			if (tTd(22, 101))
358 				printf("c=%c, s=%d; ", c, state);
359 
360 			/* chew up special characters */
361 			*q = '\0';
362 			if (bslashmode)
363 			{
364 				/* kludge \! for naive users */
365 				if (c != '!')
366 					*q++ = '\\';
367 				bslashmode = FALSE;
368 				continue;
369 			}
370 
371 			if (c == '\\')
372 			{
373 				bslashmode = TRUE;
374 				c = NOCHAR;
375 				continue;
376 			}
377 			else if (state == QST)
378 			{
379 				/* do nothing, just avoid next clauses */
380 			}
381 			else if (c == '(')
382 			{
383 				cmntcnt++;
384 				c = NOCHAR;
385 			}
386 			else if (c == ')')
387 			{
388 				if (cmntcnt <= 0)
389 				{
390 					usrerr("Unbalanced ')'");
391 					DelimChar = p;
392 					return (NULL);
393 				}
394 				else
395 					cmntcnt--;
396 			}
397 			else if (cmntcnt > 0)
398 				c = NOCHAR;
399 			else if (c == '<')
400 				anglecnt++;
401 			else if (c == '>')
402 			{
403 				if (anglecnt <= 0)
404 				{
405 					usrerr("Unbalanced '>'");
406 					DelimChar = p;
407 					return (NULL);
408 				}
409 				anglecnt--;
410 			}
411 			else if (delim == ' ' && isspace(c))
412 				c = ' ';
413 
414 			if (c == NOCHAR)
415 				continue;
416 
417 			/* see if this is end of input */
418 			if (c == delim && anglecnt <= 0 && state != QST)
419 				break;
420 
421 			newstate = StateTab[state][toktype(c)];
422 			if (tTd(22, 101))
423 				printf("ns=%02o\n", newstate);
424 			state = newstate & TYPE;
425 			if (bitset(M, newstate))
426 				c = NOCHAR;
427 			if (bitset(B, newstate))
428 				break;
429 		}
430 
431 		/* new token */
432 		if (tok != q)
433 		{
434 			*q++ = '\0';
435 			if (tTd(22, 36))
436 			{
437 				printf("tok=");
438 				xputs(tok);
439 				(void) putchar('\n');
440 			}
441 			if (avp >= &av[MAXATOM])
442 			{
443 				syserr("prescan: too many tokens");
444 				DelimChar = p;
445 				return (NULL);
446 			}
447 			*avp++ = tok;
448 		}
449 	} while (c != '\0' && (c != delim || anglecnt > 0));
450 	*avp = NULL;
451 	DelimChar = --p;
452 	if (tTd(22, 12))
453 	{
454 		printf("prescan==>");
455 		printav(av);
456 	}
457 	if (av[0] != NULL)
458 		return (av);
459 	return (NULL);
460 }
461 /*
462 **  TOKTYPE -- return token type
463 **
464 **	Parameters:
465 **		c -- the character in question.
466 **
467 **	Returns:
468 **		Its type.
469 **
470 **	Side Effects:
471 **		none.
472 */
473 
474 toktype(c)
475 	register char c;
476 {
477 	static char buf[50];
478 	static bool firstime = TRUE;
479 
480 	if (firstime)
481 	{
482 		firstime = FALSE;
483 		expand("\001o", buf, &buf[sizeof buf - 1], CurEnv);
484 		(void) strcat(buf, DELIMCHARS);
485 	}
486 	if (c == MATCHCLASS || c == MATCHREPL || c == MATCHNCLASS)
487 		return (ONE);
488 	if (c == '"')
489 		return (QST);
490 	if (!isascii(c))
491 		return (ATM);
492 	if (isspace(c) || c == ')')
493 		return (SPC);
494 	if (iscntrl(c) || strchr(buf, c) != NULL)
495 		return (OPR);
496 	return (ATM);
497 }
498 /*
499 **  REWRITE -- apply rewrite rules to token vector.
500 **
501 **	This routine is an ordered production system.  Each rewrite
502 **	rule has a LHS (called the pattern) and a RHS (called the
503 **	rewrite); 'rwr' points the the current rewrite rule.
504 **
505 **	For each rewrite rule, 'avp' points the address vector we
506 **	are trying to match against, and 'pvp' points to the pattern.
507 **	If pvp points to a special match value (MATCHZANY, MATCHANY,
508 **	MATCHONE, MATCHCLASS, MATCHNCLASS) then the address in avp
509 **	matched is saved away in the match vector (pointed to by 'mvp').
510 **
511 **	When a match between avp & pvp does not match, we try to
512 **	back out.  If we back up over MATCHONE, MATCHCLASS, or MATCHNCLASS
513 **	we must also back out the match in mvp.  If we reach a
514 **	MATCHANY or MATCHZANY we just extend the match and start
515 **	over again.
516 **
517 **	When we finally match, we rewrite the address vector
518 **	and try over again.
519 **
520 **	Parameters:
521 **		pvp -- pointer to token vector.
522 **
523 **	Returns:
524 **		none.
525 **
526 **	Side Effects:
527 **		pvp is modified.
528 */
529 
530 struct match
531 {
532 	char	**first;	/* first token matched */
533 	char	**last;		/* last token matched */
534 };
535 
536 # define MAXMATCH	9	/* max params per rewrite */
537 
538 
539 rewrite(pvp, ruleset)
540 	char **pvp;
541 	int ruleset;
542 {
543 	register char *ap;		/* address pointer */
544 	register char *rp;		/* rewrite pointer */
545 	register char **avp;		/* address vector pointer */
546 	register char **rvp;		/* rewrite vector pointer */
547 	register struct match *mlp;	/* cur ptr into mlist */
548 	register struct rewrite *rwr;	/* pointer to current rewrite rule */
549 	struct match mlist[MAXMATCH];	/* stores match on LHS */
550 	char *npvp[MAXATOM+1];		/* temporary space for rebuild */
551 
552 	if (OpMode == MD_TEST || tTd(21, 2))
553 	{
554 		printf("rewrite: ruleset %2d   input:", ruleset);
555 		printav(pvp);
556 	}
557 	if (ruleset < 0 || ruleset >= MAXRWSETS)
558 	{
559 		syserr("rewrite: illegal ruleset number %d", ruleset);
560 		return;
561 	}
562 	if (pvp == NULL)
563 		return;
564 
565 	/*
566 	**  Run through the list of rewrite rules, applying
567 	**	any that match.
568 	*/
569 
570 	for (rwr = RewriteRules[ruleset]; rwr != NULL; )
571 	{
572 		int loopcount = 0;
573 
574 		if (tTd(21, 12))
575 		{
576 			printf("-----trying rule:");
577 			printav(rwr->r_lhs);
578 		}
579 
580 		/* try to match on this rule */
581 		mlp = mlist;
582 		rvp = rwr->r_lhs;
583 		avp = pvp;
584 		while ((ap = *avp) != NULL || *rvp != NULL)
585 		{
586 			if (++loopcount > 100)
587 			{
588 				syserr("Infinite loop in ruleset %d", ruleset);
589 				printf("workspace: ");
590 				printav(pvp);
591 				break;
592 			}
593 			rp = *rvp;
594 			if (tTd(21, 35))
595 			{
596 				printf("operator=");
597 				xputs(ap);
598 				printf(", token=");
599 				xputs(rp);
600 				printf("\n");
601 			}
602 			if (rp == NULL)
603 			{
604 				/* end-of-pattern before end-of-address */
605 				goto backup;
606 			}
607 			if (ap == NULL && *rp != MATCHZANY)
608 			{
609 				/* end-of-input */
610 				break;
611 			}
612 
613 			switch (*rp)
614 			{
615 				register STAB *s;
616 
617 			  case MATCHCLASS:
618 			  case MATCHNCLASS:
619 				/* match any token in (not in) a class */
620 				s = stab(ap, ST_CLASS, ST_FIND);
621 				if (s == NULL || !bitnset(rp[1], s->s_class))
622 				{
623 					if (*rp == MATCHCLASS)
624 						goto backup;
625 				}
626 				else if (*rp == MATCHNCLASS)
627 					goto backup;
628 
629 				/* explicit fall-through */
630 
631 			  case MATCHONE:
632 			  case MATCHANY:
633 				/* match exactly one token */
634 				mlp->first = avp;
635 				mlp->last = avp++;
636 				mlp++;
637 				break;
638 
639 			  case MATCHZANY:
640 				/* match zero or more tokens */
641 				mlp->first = avp;
642 				mlp->last = avp - 1;
643 				mlp++;
644 				break;
645 
646 			  default:
647 				/* must have exact match */
648 				if (strcasecmp(rp, ap))
649 					goto backup;
650 				avp++;
651 				break;
652 			}
653 
654 			/* successful match on this token */
655 			rvp++;
656 			continue;
657 
658 		  backup:
659 			/* match failed -- back up */
660 			while (--rvp >= rwr->r_lhs)
661 			{
662 				rp = *rvp;
663 				if (*rp == MATCHANY || *rp == MATCHZANY)
664 				{
665 					/* extend binding and continue */
666 					avp = ++mlp[-1].last;
667 					avp++;
668 					rvp++;
669 					break;
670 				}
671 				avp--;
672 				if (*rp == MATCHONE || *rp == MATCHCLASS ||
673 				    *rp == MATCHNCLASS)
674 				{
675 					/* back out binding */
676 					mlp--;
677 				}
678 			}
679 
680 			if (rvp < rwr->r_lhs)
681 			{
682 				/* total failure to match */
683 				break;
684 			}
685 		}
686 
687 		/*
688 		**  See if we successfully matched
689 		*/
690 
691 		if (rvp < rwr->r_lhs || *rvp != NULL)
692 		{
693 			if (tTd(21, 10))
694 				printf("----- rule fails\n");
695 			rwr = rwr->r_next;
696 			continue;
697 		}
698 
699 		rvp = rwr->r_rhs;
700 		if (tTd(21, 12))
701 		{
702 			printf("-----rule matches:");
703 			printav(rvp);
704 		}
705 
706 		rp = *rvp;
707 		if (*rp == CANONUSER)
708 		{
709 			rvp++;
710 			rwr = rwr->r_next;
711 		}
712 		else if (*rp == CANONHOST)
713 		{
714 			rvp++;
715 			rwr = NULL;
716 		}
717 		else if (*rp == CANONNET)
718 			rwr = NULL;
719 
720 		/* substitute */
721 		for (avp = npvp; *rvp != NULL; rvp++)
722 		{
723 			register struct match *m;
724 			register char **pp;
725 
726 			rp = *rvp;
727 			if (*rp == MATCHREPL)
728 			{
729 				/* substitute from LHS */
730 				m = &mlist[rp[1] - '1'];
731 				if (m < mlist || m >= mlp)
732 				{
733 					syserr("rewrite: ruleset %d: replacement $%c out of bounds",
734 						ruleset, rp[1]);
735 					return;
736 				}
737 				if (tTd(21, 15))
738 				{
739 					printf("$%c:", rp[1]);
740 					pp = m->first;
741 					while (pp <= m->last)
742 					{
743 						printf(" %x=\"", *pp);
744 						(void) fflush(stdout);
745 						printf("%s\"", *pp++);
746 					}
747 					printf("\n");
748 				}
749 				pp = m->first;
750 				while (pp <= m->last)
751 				{
752 					if (avp >= &npvp[MAXATOM])
753 					{
754 						syserr("rewrite: expansion too long");
755 						return;
756 					}
757 					*avp++ = *pp++;
758 				}
759 			}
760 			else
761 			{
762 				/* vanilla replacement */
763 				if (avp >= &npvp[MAXATOM])
764 				{
765 	toolong:
766 					syserr("rewrite: expansion too long");
767 					return;
768 				}
769 				*avp++ = rp;
770 			}
771 		}
772 		*avp++ = NULL;
773 
774 		/*
775 		**  Check for any hostname/keyword lookups.
776 		*/
777 
778 		for (rvp = npvp; *rvp != NULL; rvp++)
779 		{
780 			char **hbrvp;
781 			char **xpvp;
782 			int trsize;
783 			char *olddelimchar;
784 			char *replac;
785 			int endtoken;
786 			STAB *map;
787 			char *mapname;
788 			char **key_rvp;
789 			char **arg_rvp;
790 			char **default_rvp;
791 			char buf[MAXNAME + 1];
792 			char *pvpb1[MAXATOM + 1];
793 			char pvpbuf[PSBUFSIZE];
794 			extern char *DelimChar;
795 
796 			if (**rvp != HOSTBEGIN && **rvp != LOOKUPBEGIN)
797 				continue;
798 
799 			/*
800 			**  Got a hostname/keyword lookup.
801 			**
802 			**	This could be optimized fairly easily.
803 			*/
804 
805 			hbrvp = rvp;
806 			arg_rvp = default_rvp = NULL;
807 			if (**rvp == HOSTBEGIN)
808 			{
809 				endtoken = HOSTEND;
810 				mapname = "host";
811 			}
812 			else
813 			{
814 				endtoken = LOOKUPEND;
815 				mapname = *++rvp;
816 			}
817 			map = stab(mapname, ST_MAP, ST_FIND);
818 			if (map == NULL)
819 				syserr("rewrite: map %s not found", mapname);
820 
821 			/* extract the match part */
822 			key_rvp = ++rvp;
823 			while (*rvp != NULL && **rvp != endtoken)
824 			{
825 				switch (**rvp)
826 				{
827 				  case CANONHOST:
828 					*rvp++ = NULL;
829 					arg_rvp = rvp;
830 					break;
831 
832 				  case CANONUSER:
833 					*rvp++ = NULL;
834 					default_rvp = rvp;
835 					break;
836 
837 				  default:
838 					rvp++;
839 					break;
840 				}
841 			}
842 			if (*rvp != NULL)
843 				*rvp++ = NULL;
844 
845 			/* save the remainder of the input string */
846 			trsize = (int) (avp - rvp + 1) * sizeof *rvp;
847 			bcopy((char *) rvp, (char *) pvpb1, trsize);
848 
849 			/* look it up */
850 			cataddr(key_rvp, buf, sizeof buf);
851 			if (map != NULL && bitset(MF_VALID, map->s_map.map_flags))
852 				replac = (*map->s_map.map_class->map_lookup)(buf,
853 						sizeof buf - 1, arg_rvp);
854 			else
855 				replac = NULL;
856 
857 			/* if no replacement, use default */
858 			if (replac == NULL)
859 			{
860 				if (default_rvp != NULL)
861 					xpvp = default_rvp;
862 				else
863 					xpvp = key_rvp;
864 			}
865 			else
866 			{
867 				/* scan the new replacement */
868 				olddelimchar = DelimChar;
869 				xpvp = prescan(replac, '\0', pvpbuf);
870 				DelimChar = olddelimchar;
871 				if (xpvp == NULL)
872 				{
873 					syserr("rewrite: cannot prescan map value: %s", replac);
874 					return;
875 				}
876 			}
877 
878 			/* append it to the token list */
879 			for (avp = hbrvp; *xpvp != NULL; xpvp++)
880 			{
881 				*avp++ = newstr(*xpvp);
882 				if (avp >= &npvp[MAXATOM])
883 					goto toolong;
884 			}
885 
886 			/* restore the old trailing information */
887 			for (xpvp = pvpb1; (*avp++ = *xpvp++) != NULL; )
888 				if (avp >= &npvp[MAXATOM])
889 					goto toolong;
890 
891 			break;
892 		}
893 
894 		/*
895 		**  Check for subroutine calls.
896 		*/
897 
898 		if (*npvp != NULL && **npvp == CALLSUBR)
899 		{
900 			bcopy((char *) &npvp[2], (char *) pvp,
901 				(int) (avp - npvp - 2) * sizeof *avp);
902 			if (tTd(21, 3))
903 				printf("-----callsubr %s\n", npvp[1]);
904 			rewrite(pvp, atoi(npvp[1]));
905 		}
906 		else
907 		{
908 			bcopy((char *) npvp, (char *) pvp,
909 				(int) (avp - npvp) * sizeof *avp);
910 		}
911 		if (tTd(21, 4))
912 		{
913 			printf("rewritten as:");
914 			printav(pvp);
915 		}
916 	}
917 
918 	if (OpMode == MD_TEST || tTd(21, 2))
919 	{
920 		printf("rewrite: ruleset %2d returns:", ruleset);
921 		printav(pvp);
922 	}
923 }
924 /*
925 **  BUILDADDR -- build address from token vector.
926 **
927 **	Parameters:
928 **		tv -- token vector.
929 **		a -- pointer to address descriptor to fill.
930 **			If NULL, one will be allocated.
931 **
932 **	Returns:
933 **		NULL if there was an error.
934 **		'a' otherwise.
935 **
936 **	Side Effects:
937 **		fills in 'a'
938 */
939 
940 ADDRESS *
941 buildaddr(tv, a)
942 	register char **tv;
943 	register ADDRESS *a;
944 {
945 	static char buf[MAXNAME];
946 	struct mailer **mp;
947 	register struct mailer *m;
948 
949 	if (a == NULL)
950 		a = (ADDRESS *) xalloc(sizeof *a);
951 	bzero((char *) a, sizeof *a);
952 
953 	/* figure out what net/mailer to use */
954 	if (**tv != CANONNET)
955 	{
956 		syserr("buildaddr: no net");
957 		return (NULL);
958 	}
959 	tv++;
960 	if (!strcasecmp(*tv, "error"))
961 	{
962 		if (**++tv == CANONHOST)
963 		{
964 			setstat(atoi(*++tv));
965 			tv++;
966 		}
967 		if (**tv != CANONUSER)
968 			syserr("buildaddr: error: no user");
969 		buf[0] = '\0';
970 		while (*++tv != NULL)
971 		{
972 			if (buf[0] != '\0')
973 				(void) strcat(buf, " ");
974 			(void) strcat(buf, *tv);
975 		}
976 		usrerr(buf);
977 		return (NULL);
978 	}
979 	for (mp = Mailer; (m = *mp++) != NULL; )
980 	{
981 		if (!strcasecmp(m->m_name, *tv))
982 			break;
983 	}
984 	if (m == NULL)
985 	{
986 		syserr("buildaddr: unknown mailer %s", *tv);
987 		return (NULL);
988 	}
989 	a->q_mailer = m;
990 
991 	/* figure out what host (if any) */
992 	tv++;
993 	if (!bitnset(M_LOCAL, m->m_flags))
994 	{
995 		if (**tv++ != CANONHOST)
996 		{
997 			syserr("buildaddr: no host");
998 			return (NULL);
999 		}
1000 		buf[0] = '\0';
1001 		while (*tv != NULL && **tv != CANONUSER)
1002 			(void) strcat(buf, *tv++);
1003 		a->q_host = newstr(buf);
1004 	}
1005 	else
1006 		a->q_host = NULL;
1007 
1008 	/* figure out the user */
1009 	if (*tv == NULL || **tv != CANONUSER)
1010 	{
1011 		syserr("buildaddr: no user");
1012 		return (NULL);
1013 	}
1014 
1015 	if (m == LocalMailer && tv[1] != NULL && strcmp(tv[1], "@") == 0)
1016 	{
1017 		tv++;
1018 		a->q_flags |= QNOTREMOTE;
1019 	}
1020 
1021 	/* rewrite according recipient mailer rewriting rules */
1022 	rewrite(++tv, 2);
1023 	if (m->m_r_rwset > 0)
1024 		rewrite(tv, m->m_r_rwset);
1025 	rewrite(tv, 4);
1026 
1027 	/* save the result for the command line/RCPT argument */
1028 	cataddr(tv, buf, sizeof buf);
1029 	a->q_user = buf;
1030 
1031 	return (a);
1032 }
1033 /*
1034 **  CATADDR -- concatenate pieces of addresses (putting in <LWSP> subs)
1035 **
1036 **	Parameters:
1037 **		pvp -- parameter vector to rebuild.
1038 **		buf -- buffer to build the string into.
1039 **		sz -- size of buf.
1040 **
1041 **	Returns:
1042 **		none.
1043 **
1044 **	Side Effects:
1045 **		Destroys buf.
1046 */
1047 
1048 cataddr(pvp, buf, sz)
1049 	char **pvp;
1050 	char *buf;
1051 	register int sz;
1052 {
1053 	bool oatomtok = FALSE;
1054 	bool natomtok = FALSE;
1055 	register int i;
1056 	register char *p;
1057 
1058 	if (pvp == NULL)
1059 	{
1060 		(void) strcpy(buf, "");
1061 		return;
1062 	}
1063 	p = buf;
1064 	sz -= 2;
1065 	while (*pvp != NULL && (i = strlen(*pvp)) < sz)
1066 	{
1067 		natomtok = (toktype(**pvp) == ATM);
1068 		if (oatomtok && natomtok)
1069 			*p++ = SpaceSub;
1070 		(void) strcpy(p, *pvp);
1071 		oatomtok = natomtok;
1072 		p += i;
1073 		sz -= i + 1;
1074 		pvp++;
1075 	}
1076 	*p = '\0';
1077 }
1078 /*
1079 **  SAMEADDR -- Determine if two addresses are the same
1080 **
1081 **	This is not just a straight comparison -- if the mailer doesn't
1082 **	care about the host we just ignore it, etc.
1083 **
1084 **	Parameters:
1085 **		a, b -- pointers to the internal forms to compare.
1086 **
1087 **	Returns:
1088 **		TRUE -- they represent the same mailbox.
1089 **		FALSE -- they don't.
1090 **
1091 **	Side Effects:
1092 **		none.
1093 */
1094 
1095 bool
1096 sameaddr(a, b)
1097 	register ADDRESS *a;
1098 	register ADDRESS *b;
1099 {
1100 	/* if they don't have the same mailer, forget it */
1101 	if (a->q_mailer != b->q_mailer)
1102 		return (FALSE);
1103 
1104 	/* if the user isn't the same, we can drop out */
1105 	if (strcmp(a->q_user, b->q_user) != 0)
1106 		return (FALSE);
1107 
1108 	/* if the mailer ignores hosts, we have succeeded! */
1109 	if (bitnset(M_LOCAL, a->q_mailer->m_flags))
1110 		return (TRUE);
1111 
1112 	/* otherwise compare hosts (but be careful for NULL ptrs) */
1113 	if (a->q_host == NULL || b->q_host == NULL)
1114 		return (FALSE);
1115 	if (strcmp(a->q_host, b->q_host) != 0)
1116 		return (FALSE);
1117 
1118 	return (TRUE);
1119 }
1120 /*
1121 **  PRINTADDR -- print address (for debugging)
1122 **
1123 **	Parameters:
1124 **		a -- the address to print
1125 **		follow -- follow the q_next chain.
1126 **
1127 **	Returns:
1128 **		none.
1129 **
1130 **	Side Effects:
1131 **		none.
1132 */
1133 
1134 printaddr(a, follow)
1135 	register ADDRESS *a;
1136 	bool follow;
1137 {
1138 	bool first = TRUE;
1139 
1140 	while (a != NULL)
1141 	{
1142 		first = FALSE;
1143 		printf("%x=", a);
1144 		(void) fflush(stdout);
1145 		printf("%s: mailer %d (%s), host `%s', user `%s', ruser `%s'\n",
1146 		       a->q_paddr, a->q_mailer->m_mno, a->q_mailer->m_name,
1147 		       a->q_host, a->q_user, a->q_ruser? a->q_ruser: "<null>");
1148 		printf("\tnext=%x, flags=%o, alias %x\n", a->q_next, a->q_flags,
1149 		       a->q_alias);
1150 		printf("\thome=\"%s\", fullname=\"%s\"\n", a->q_home,
1151 		       a->q_fullname);
1152 
1153 		if (!follow)
1154 			return;
1155 		a = a->q_next;
1156 	}
1157 	if (first)
1158 		printf("[NULL]\n");
1159 }
1160 
1161 /*
1162 **  REMOTENAME -- return the name relative to the current mailer
1163 **
1164 **	Parameters:
1165 **		name -- the name to translate.
1166 **		m -- the mailer that we want to do rewriting relative
1167 **			to.
1168 **		senderaddress -- if set, uses the sender rewriting rules
1169 **			rather than the recipient rewriting rules.
1170 **		canonical -- if set, strip out any comment information,
1171 **			etc.
1172 **
1173 **	Returns:
1174 **		the text string representing this address relative to
1175 **			the receiving mailer.
1176 **
1177 **	Side Effects:
1178 **		none.
1179 **
1180 **	Warnings:
1181 **		The text string returned is tucked away locally;
1182 **			copy it if you intend to save it.
1183 */
1184 
1185 char *
1186 remotename(name, m, senderaddress, canonical, e)
1187 	char *name;
1188 	struct mailer *m;
1189 	bool senderaddress;
1190 	bool canonical;
1191 	register ENVELOPE *e;
1192 {
1193 	register char **pvp;
1194 	char *fancy;
1195 	extern char *macvalue();
1196 	char *oldg = macvalue('g', e);
1197 	static char buf[MAXNAME];
1198 	char lbuf[MAXNAME];
1199 	char pvpbuf[PSBUFSIZE];
1200 	extern char **prescan();
1201 	extern char *crackaddr();
1202 
1203 	if (tTd(12, 1))
1204 		printf("remotename(%s)\n", name);
1205 
1206 	/* don't do anything if we are tagging it as special */
1207 	if ((senderaddress ? m->m_s_rwset : m->m_r_rwset) < 0)
1208 		return (name);
1209 
1210 	/*
1211 	**  Do a heuristic crack of this name to extract any comment info.
1212 	**	This will leave the name as a comment and a $g macro.
1213 	*/
1214 
1215 	if (canonical)
1216 		fancy = "\001g";
1217 	else
1218 		fancy = crackaddr(name);
1219 
1220 	/*
1221 	**  Turn the name into canonical form.
1222 	**	Normally this will be RFC 822 style, i.e., "user@domain".
1223 	**	If this only resolves to "user", and the "C" flag is
1224 	**	specified in the sending mailer, then the sender's
1225 	**	domain will be appended.
1226 	*/
1227 
1228 	pvp = prescan(name, '\0', pvpbuf);
1229 	if (pvp == NULL)
1230 		return (name);
1231 	rewrite(pvp, 3);
1232 	if (e->e_fromdomain != NULL)
1233 	{
1234 		/* append from domain to this address */
1235 		register char **pxp = pvp;
1236 
1237 		/* see if there is an "@domain" in the current name */
1238 		while (*pxp != NULL && strcmp(*pxp, "@") != 0)
1239 			pxp++;
1240 		if (*pxp == NULL)
1241 		{
1242 			/* no.... append the "@domain" from the sender */
1243 			register char **qxq = e->e_fromdomain;
1244 
1245 			while ((*pxp++ = *qxq++) != NULL)
1246 				continue;
1247 			rewrite(pvp, 3);
1248 		}
1249 	}
1250 
1251 	/*
1252 	**  Do more specific rewriting.
1253 	**	Rewrite using ruleset 1 or 2 depending on whether this is
1254 	**		a sender address or not.
1255 	**	Then run it through any receiving-mailer-specific rulesets.
1256 	*/
1257 
1258 	if (senderaddress)
1259 	{
1260 		rewrite(pvp, 1);
1261 		if (m->m_s_rwset > 0)
1262 			rewrite(pvp, m->m_s_rwset);
1263 	}
1264 	else
1265 	{
1266 		rewrite(pvp, 2);
1267 		if (m->m_r_rwset > 0)
1268 			rewrite(pvp, m->m_r_rwset);
1269 	}
1270 
1271 	/*
1272 	**  Do any final sanitation the address may require.
1273 	**	This will normally be used to turn internal forms
1274 	**	(e.g., user@host.LOCAL) into external form.  This
1275 	**	may be used as a default to the above rules.
1276 	*/
1277 
1278 	rewrite(pvp, 4);
1279 
1280 	/*
1281 	**  Now restore the comment information we had at the beginning.
1282 	*/
1283 
1284 	cataddr(pvp, lbuf, sizeof lbuf);
1285 	define('g', lbuf, e);
1286 	expand(fancy, buf, &buf[sizeof buf - 1], e);
1287 	define('g', oldg, e);
1288 
1289 	if (tTd(12, 1))
1290 		printf("remotename => `%s'\n", buf);
1291 	return (buf);
1292 }
1293 /*
1294 **  MAPLOCALUSER -- run local username through ruleset 5 for final redirection
1295 **
1296 **	Parameters:
1297 **		a -- the address to map (but just the user name part).
1298 **		sendq -- the sendq in which to install any replacement
1299 **			addresses.
1300 **
1301 **	Returns:
1302 **		none.
1303 */
1304 
1305 maplocaluser(a, sendq, e)
1306 	register ADDRESS *a;
1307 	ADDRESS **sendq;
1308 	ENVELOPE *e;
1309 {
1310 	register char **pvp;
1311 	register ADDRESS *a1 = NULL;
1312 	char pvpbuf[PSBUFSIZE];
1313 
1314 	if (tTd(29, 1))
1315 	{
1316 		printf("maplocaluser: ");
1317 		printaddr(a, FALSE);
1318 	}
1319 	pvp = prescan(a->q_user, '\0', pvpbuf);
1320 	if (pvp == NULL)
1321 		return;
1322 
1323 	rewrite(pvp, 5);
1324 	if (pvp[0] == NULL || pvp[0][0] != CANONNET)
1325 		return;
1326 
1327 	/* if non-null, mailer destination specified -- has it changed? */
1328 	a1 = buildaddr(pvp, NULL);
1329 	if (a1 == NULL || sameaddr(a, a1))
1330 		return;
1331 
1332 	/* mark old address as dead; insert new address */
1333 	a->q_flags |= QDONTSEND;
1334 	a1->q_alias = a;
1335 	allocaddr(a1, 1, NULL);
1336 	(void) recipient(a1, sendq, e);
1337 }
1338