1 /*
2  * Copyright (c) 1983 Eric P. Allman
3  * Copyright (c) 1988 Regents of the University of California.
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms are permitted
7  * provided that the above copyright notice and this paragraph are
8  * duplicated in all such forms and that any documentation,
9  * advertising materials, and other materials related to such
10  * distribution and use acknowledge that the software was developed
11  * by the University of California, Berkeley.  The name of the
12  * University may not be used to endorse or promote products derived
13  * from this software without specific prior written permission.
14  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
16  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
17  */
18 
19 #ifndef lint
20 static char sccsid[] = "@(#)parseaddr.c	5.10 (Berkeley) 01/01/89";
21 #endif /* not lint */
22 
23 # include "sendmail.h"
24 
25 /*
26 **  PARSEADDR -- Parse an address
27 **
28 **	Parses an address and breaks it up into three parts: a
29 **	net to transmit the message on, the host to transmit it
30 **	to, and a user on that host.  These are loaded into an
31 **	ADDRESS header with the values squirreled away if necessary.
32 **	The "user" part may not be a real user; the process may
33 **	just reoccur on that machine.  For example, on a machine
34 **	with an arpanet connection, the address
35 **		csvax.bill@berkeley
36 **	will break up to a "user" of 'csvax.bill' and a host
37 **	of 'berkeley' -- to be transmitted over the arpanet.
38 **
39 **	Parameters:
40 **		addr -- the address to parse.
41 **		a -- a pointer to the address descriptor buffer.
42 **			If NULL, a header will be created.
43 **		copyf -- determines what shall be copied:
44 **			-1 -- don't copy anything.  The printname
45 **				(q_paddr) is just addr, and the
46 **				user & host are allocated internally
47 **				to parse.
48 **			0 -- copy out the parsed user & host, but
49 **				don't copy the printname.
50 **			+1 -- copy everything.
51 **		delim -- the character to terminate the address, passed
52 **			to prescan.
53 **
54 **	Returns:
55 **		A pointer to the address descriptor header (`a' if
56 **			`a' is non-NULL).
57 **		NULL on error.
58 **
59 **	Side Effects:
60 **		none
61 */
62 
63 /* following delimiters are inherent to the internal algorithms */
64 # define DELIMCHARS	"\001()<>,;\\\"\r\n"	/* word delimiters */
65 
66 ADDRESS *
67 parseaddr(addr, a, copyf, delim)
68 	char *addr;
69 	register ADDRESS *a;
70 	int copyf;
71 	char delim;
72 {
73 	register char **pvp;
74 	register struct mailer *m;
75 	char pvpbuf[PSBUFSIZE];
76 	extern char **prescan();
77 	extern ADDRESS *buildaddr();
78 
79 	/*
80 	**  Initialize and prescan address.
81 	*/
82 
83 	CurEnv->e_to = addr;
84 	if (tTd(20, 1))
85 		printf("\n--parseaddr(%s)\n", addr);
86 
87 	pvp = prescan(addr, delim, pvpbuf);
88 	if (pvp == NULL)
89 		return (NULL);
90 
91 	/*
92 	**  Apply rewriting rules.
93 	**	Ruleset 0 does basic parsing.  It must resolve.
94 	*/
95 
96 	rewrite(pvp, 3);
97 	rewrite(pvp, 0);
98 
99 	/*
100 	**  See if we resolved to a real mailer.
101 	*/
102 
103 	if (pvp[0][0] != CANONNET)
104 	{
105 		setstat(EX_USAGE);
106 		usrerr("cannot resolve name");
107 		return (NULL);
108 	}
109 
110 	/*
111 	**  Build canonical address from pvp.
112 	*/
113 
114 	a = buildaddr(pvp, a);
115 	if (a == NULL)
116 		return (NULL);
117 	m = a->q_mailer;
118 
119 	/*
120 	**  Make local copies of the host & user and then
121 	**  transport them out.
122 	*/
123 
124 	if (copyf > 0)
125 	{
126 		extern char *DelimChar;
127 		char savec = *DelimChar;
128 
129 		*DelimChar = '\0';
130 		a->q_paddr = newstr(addr);
131 		*DelimChar = savec;
132 	}
133 	else
134 		a->q_paddr = addr;
135 
136 	if (a->q_user == NULL)
137 		a->q_user = "";
138 	if (a->q_host == NULL)
139 		a->q_host = "";
140 
141 	if (copyf >= 0)
142 	{
143 		a->q_host = newstr(a->q_host);
144 		if (a->q_user != a->q_paddr)
145 			a->q_user = newstr(a->q_user);
146 	}
147 
148 	/*
149 	**  Convert host name to lower case if requested.
150 	**	User name will be done later.
151 	*/
152 
153 	if (!bitnset(M_HST_UPPER, m->m_flags))
154 		makelower(a->q_host);
155 
156 	/*
157 	**  Compute return value.
158 	*/
159 
160 	if (tTd(20, 1))
161 	{
162 		printf("parseaddr-->");
163 		printaddr(a, FALSE);
164 	}
165 
166 	return (a);
167 }
168 /*
169 **  LOWERADDR -- map UPPER->lower case on addresses as requested.
170 **
171 **	Parameters:
172 **		a -- address to be mapped.
173 **
174 **	Returns:
175 **		none.
176 **
177 **	Side Effects:
178 **		none.
179 */
180 
181 loweraddr(a)
182 	register ADDRESS *a;
183 {
184 	register MAILER *m = a->q_mailer;
185 
186 	if (!bitnset(M_USR_UPPER, m->m_flags))
187 		makelower(a->q_user);
188 }
189 /*
190 **  PRESCAN -- Prescan name and make it canonical
191 **
192 **	Scans a name and turns it into a set of tokens.  This process
193 **	deletes blanks and comments (in parentheses).
194 **
195 **	This routine knows about quoted strings and angle brackets.
196 **
197 **	There are certain subtleties to this routine.  The one that
198 **	comes to mind now is that backslashes on the ends of names
199 **	are silently stripped off; this is intentional.  The problem
200 **	is that some versions of sndmsg (like at LBL) set the kill
201 **	character to something other than @ when reading addresses;
202 **	so people type "csvax.eric\@berkeley" -- which screws up the
203 **	berknet mailer.
204 **
205 **	Parameters:
206 **		addr -- the name to chomp.
207 **		delim -- the delimiter for the address, normally
208 **			'\0' or ','; \0 is accepted in any case.
209 **			If '\t' then we are reading the .cf file.
210 **		pvpbuf -- place to put the saved text -- note that
211 **			the pointers are static.
212 **
213 **	Returns:
214 **		A pointer to a vector of tokens.
215 **		NULL on error.
216 **
217 **	Side Effects:
218 **		sets DelimChar to point to the character matching 'delim'.
219 */
220 
221 /* states and character types */
222 # define OPR		0	/* operator */
223 # define ATM		1	/* atom */
224 # define QST		2	/* in quoted string */
225 # define SPC		3	/* chewing up spaces */
226 # define ONE		4	/* pick up one character */
227 
228 # define NSTATES	5	/* number of states */
229 # define TYPE		017	/* mask to select state type */
230 
231 /* meta bits for table */
232 # define M		020	/* meta character; don't pass through */
233 # define B		040	/* cause a break */
234 # define MB		M|B	/* meta-break */
235 
236 static short StateTab[NSTATES][NSTATES] =
237 {
238    /*	oldst	chtype>	OPR	ATM	QST	SPC	ONE	*/
239 	/*OPR*/		OPR|B,	ATM|B,	QST|B,	SPC|MB,	ONE|B,
240 	/*ATM*/		OPR|B,	ATM,	QST|B,	SPC|MB,	ONE|B,
241 	/*QST*/		QST,	QST,	OPR,	QST,	QST,
242 	/*SPC*/		OPR,	ATM,	QST,	SPC|M,	ONE,
243 	/*ONE*/		OPR,	OPR,	OPR,	OPR,	OPR,
244 };
245 
246 # define NOCHAR		-1	/* signal nothing in lookahead token */
247 
248 char	*DelimChar;		/* set to point to the delimiter */
249 
250 char **
251 prescan(addr, delim, pvpbuf)
252 	char *addr;
253 	char delim;
254 	char pvpbuf[];
255 {
256 	register char *p;
257 	register char *q;
258 	register int c;
259 	char **avp;
260 	bool bslashmode;
261 	int cmntcnt;
262 	int anglecnt;
263 	char *tok;
264 	int state;
265 	int newstate;
266 	static char *av[MAXATOM+1];
267 	extern int errno;
268 
269 	/* make sure error messages don't have garbage on them */
270 	errno = 0;
271 
272 	q = pvpbuf;
273 	bslashmode = FALSE;
274 	cmntcnt = 0;
275 	anglecnt = 0;
276 	avp = av;
277 	state = OPR;
278 	c = NOCHAR;
279 	p = addr;
280 	if (tTd(22, 45))
281 	{
282 		printf("prescan: ");
283 		xputs(p);
284 		(void) putchar('\n');
285 	}
286 
287 	do
288 	{
289 		/* read a token */
290 		tok = q;
291 		for (;;)
292 		{
293 			/* store away any old lookahead character */
294 			if (c != NOCHAR)
295 			{
296 				/* see if there is room */
297 				if (q >= &pvpbuf[PSBUFSIZE - 5])
298 				{
299 					usrerr("Address too long");
300 					DelimChar = p;
301 					return (NULL);
302 				}
303 
304 				/* squirrel it away */
305 				*q++ = c;
306 			}
307 
308 			/* read a new input character */
309 			c = *p++;
310 			if (c == '\0')
311 				break;
312 			c &= ~0200;
313 
314 			if (tTd(22, 101))
315 				printf("c=%c, s=%d; ", c, state);
316 
317 			/* chew up special characters */
318 			*q = '\0';
319 			if (bslashmode)
320 			{
321 				/* kludge \! for naive users */
322 				if (c != '!')
323 					c |= 0200;
324 				bslashmode = FALSE;
325 			}
326 			else if (c == '\\')
327 			{
328 				bslashmode = TRUE;
329 				c = NOCHAR;
330 			}
331 			else if (state == QST)
332 			{
333 				/* do nothing, just avoid next clauses */
334 			}
335 			else if (c == '(')
336 			{
337 				cmntcnt++;
338 				c = NOCHAR;
339 			}
340 			else if (c == ')')
341 			{
342 				if (cmntcnt <= 0)
343 				{
344 					usrerr("Unbalanced ')'");
345 					DelimChar = p;
346 					return (NULL);
347 				}
348 				else
349 					cmntcnt--;
350 			}
351 			else if (cmntcnt > 0)
352 				c = NOCHAR;
353 			else if (c == '<')
354 				anglecnt++;
355 			else if (c == '>')
356 			{
357 				if (anglecnt <= 0)
358 				{
359 					usrerr("Unbalanced '>'");
360 					DelimChar = p;
361 					return (NULL);
362 				}
363 				anglecnt--;
364 			}
365 			else if (delim == ' ' && isspace(c))
366 				c = ' ';
367 
368 			if (c == NOCHAR)
369 				continue;
370 
371 			/* see if this is end of input */
372 			if (c == delim && anglecnt <= 0 && state != QST)
373 				break;
374 
375 			newstate = StateTab[state][toktype(c)];
376 			if (tTd(22, 101))
377 				printf("ns=%02o\n", newstate);
378 			state = newstate & TYPE;
379 			if (bitset(M, newstate))
380 				c = NOCHAR;
381 			if (bitset(B, newstate))
382 				break;
383 		}
384 
385 		/* new token */
386 		if (tok != q)
387 		{
388 			*q++ = '\0';
389 			if (tTd(22, 36))
390 			{
391 				printf("tok=");
392 				xputs(tok);
393 				(void) putchar('\n');
394 			}
395 			if (avp >= &av[MAXATOM])
396 			{
397 				syserr("prescan: too many tokens");
398 				DelimChar = p;
399 				return (NULL);
400 			}
401 			*avp++ = tok;
402 		}
403 	} while (c != '\0' && (c != delim || anglecnt > 0));
404 	*avp = NULL;
405 	DelimChar = --p;
406 	if (cmntcnt > 0)
407 		usrerr("Unbalanced '('");
408 	else if (anglecnt > 0)
409 		usrerr("Unbalanced '<'");
410 	else if (state == QST)
411 		usrerr("Unbalanced '\"'");
412 	else if (av[0] != NULL)
413 		return (av);
414 	return (NULL);
415 }
416 /*
417 **  TOKTYPE -- return token type
418 **
419 **	Parameters:
420 **		c -- the character in question.
421 **
422 **	Returns:
423 **		Its type.
424 **
425 **	Side Effects:
426 **		none.
427 */
428 
429 toktype(c)
430 	register char c;
431 {
432 	static char buf[50];
433 	static bool firstime = TRUE;
434 
435 	if (firstime)
436 	{
437 		firstime = FALSE;
438 		expand("\001o", buf, &buf[sizeof buf - 1], CurEnv);
439 		(void) strcat(buf, DELIMCHARS);
440 	}
441 	if (c == MATCHCLASS || c == MATCHREPL || c == MATCHNCLASS)
442 		return (ONE);
443 	if (c == '"')
444 		return (QST);
445 	if (!isascii(c))
446 		return (ATM);
447 	if (isspace(c) || c == ')')
448 		return (SPC);
449 	if (iscntrl(c) || index(buf, c) != NULL)
450 		return (OPR);
451 	return (ATM);
452 }
453 /*
454 **  REWRITE -- apply rewrite rules to token vector.
455 **
456 **	This routine is an ordered production system.  Each rewrite
457 **	rule has a LHS (called the pattern) and a RHS (called the
458 **	rewrite); 'rwr' points the the current rewrite rule.
459 **
460 **	For each rewrite rule, 'avp' points the address vector we
461 **	are trying to match against, and 'pvp' points to the pattern.
462 **	If pvp points to a special match value (MATCHZANY, MATCHANY,
463 **	MATCHONE, MATCHCLASS, MATCHNCLASS) then the address in avp
464 **	matched is saved away in the match vector (pointed to by 'mvp').
465 **
466 **	When a match between avp & pvp does not match, we try to
467 **	back out.  If we back up over MATCHONE, MATCHCLASS, or MATCHNCLASS
468 **	we must also back out the match in mvp.  If we reach a
469 **	MATCHANY or MATCHZANY we just extend the match and start
470 **	over again.
471 **
472 **	When we finally match, we rewrite the address vector
473 **	and try over again.
474 **
475 **	Parameters:
476 **		pvp -- pointer to token vector.
477 **
478 **	Returns:
479 **		none.
480 **
481 **	Side Effects:
482 **		pvp is modified.
483 */
484 
485 struct match
486 {
487 	char	**first;	/* first token matched */
488 	char	**last;		/* last token matched */
489 };
490 
491 # define MAXMATCH	9	/* max params per rewrite */
492 
493 
494 rewrite(pvp, ruleset)
495 	char **pvp;
496 	int ruleset;
497 {
498 	register char *ap;		/* address pointer */
499 	register char *rp;		/* rewrite pointer */
500 	register char **avp;		/* address vector pointer */
501 	register char **rvp;		/* rewrite vector pointer */
502 	register struct match *mlp;	/* cur ptr into mlist */
503 	register struct rewrite *rwr;	/* pointer to current rewrite rule */
504 	struct match mlist[MAXMATCH];	/* stores match on LHS */
505 	char *npvp[MAXATOM+1];		/* temporary space for rebuild */
506 
507 	if (OpMode == MD_TEST || tTd(21, 2))
508 	{
509 		printf("rewrite: ruleset %2d   input:", ruleset);
510 		printav(pvp);
511 	}
512 	if (pvp == NULL)
513 		return;
514 
515 	/*
516 	**  Run through the list of rewrite rules, applying
517 	**	any that match.
518 	*/
519 
520 	for (rwr = RewriteRules[ruleset]; rwr != NULL; )
521 	{
522 		if (tTd(21, 12))
523 		{
524 			printf("-----trying rule:");
525 			printav(rwr->r_lhs);
526 		}
527 
528 		/* try to match on this rule */
529 		mlp = mlist;
530 		rvp = rwr->r_lhs;
531 		avp = pvp;
532 		while ((ap = *avp) != NULL || *rvp != NULL)
533 		{
534 			rp = *rvp;
535 			if (tTd(21, 35))
536 			{
537 				printf("ap=");
538 				xputs(ap);
539 				printf(", rp=");
540 				xputs(rp);
541 				printf("\n");
542 			}
543 			if (rp == NULL)
544 			{
545 				/* end-of-pattern before end-of-address */
546 				goto backup;
547 			}
548 			if (ap == NULL && *rp != MATCHZANY)
549 			{
550 				/* end-of-input */
551 				break;
552 			}
553 
554 			switch (*rp)
555 			{
556 				register STAB *s;
557 
558 			  case MATCHCLASS:
559 			  case MATCHNCLASS:
560 				/* match any token in (not in) a class */
561 				s = stab(ap, ST_CLASS, ST_FIND);
562 				if (s == NULL || !bitnset(rp[1], s->s_class))
563 				{
564 					if (*rp == MATCHCLASS)
565 						goto backup;
566 				}
567 				else if (*rp == MATCHNCLASS)
568 					goto backup;
569 
570 				/* explicit fall-through */
571 
572 			  case MATCHONE:
573 			  case MATCHANY:
574 				/* match exactly one token */
575 				mlp->first = avp;
576 				mlp->last = avp++;
577 				mlp++;
578 				break;
579 
580 			  case MATCHZANY:
581 				/* match zero or more tokens */
582 				mlp->first = avp;
583 				mlp->last = avp - 1;
584 				mlp++;
585 				break;
586 
587 			  default:
588 				/* must have exact match */
589 				if (strcasecmp(rp, ap))
590 					goto backup;
591 				avp++;
592 				break;
593 			}
594 
595 			/* successful match on this token */
596 			rvp++;
597 			continue;
598 
599 		  backup:
600 			/* match failed -- back up */
601 			while (--rvp >= rwr->r_lhs)
602 			{
603 				rp = *rvp;
604 				if (*rp == MATCHANY || *rp == MATCHZANY)
605 				{
606 					/* extend binding and continue */
607 					avp = ++mlp[-1].last;
608 					avp++;
609 					rvp++;
610 					break;
611 				}
612 				avp--;
613 				if (*rp == MATCHONE || *rp == MATCHCLASS ||
614 				    *rp == MATCHNCLASS)
615 				{
616 					/* back out binding */
617 					mlp--;
618 				}
619 			}
620 
621 			if (rvp < rwr->r_lhs)
622 			{
623 				/* total failure to match */
624 				break;
625 			}
626 		}
627 
628 		/*
629 		**  See if we successfully matched
630 		*/
631 
632 		if (rvp < rwr->r_lhs || *rvp != NULL)
633 		{
634 			if (tTd(21, 10))
635 				printf("----- rule fails\n");
636 			rwr = rwr->r_next;
637 			continue;
638 		}
639 
640 		rvp = rwr->r_rhs;
641 		if (tTd(21, 12))
642 		{
643 			printf("-----rule matches:");
644 			printav(rvp);
645 		}
646 
647 		rp = *rvp;
648 		if (*rp == CANONUSER)
649 		{
650 			rvp++;
651 			rwr = rwr->r_next;
652 		}
653 		else if (*rp == CANONHOST)
654 		{
655 			rvp++;
656 			rwr = NULL;
657 		}
658 		else if (*rp == CANONNET)
659 			rwr = NULL;
660 
661 		/* substitute */
662 		for (avp = npvp; *rvp != NULL; rvp++)
663 		{
664 			register struct match *m;
665 			register char **pp;
666 
667 			rp = *rvp;
668 			if (*rp == MATCHREPL)
669 			{
670 				/* substitute from LHS */
671 				m = &mlist[rp[1] - '1'];
672 				if (m >= mlp)
673 				{
674 					syserr("rewrite: ruleset %d: replacement out of bounds", ruleset);
675 					return;
676 				}
677 				if (tTd(21, 15))
678 				{
679 					printf("$%c:", rp[1]);
680 					pp = m->first;
681 					while (pp <= m->last)
682 					{
683 						printf(" %x=\"", *pp);
684 						(void) fflush(stdout);
685 						printf("%s\"", *pp++);
686 					}
687 					printf("\n");
688 				}
689 				pp = m->first;
690 				while (pp <= m->last)
691 				{
692 					if (avp >= &npvp[MAXATOM])
693 					{
694 						syserr("rewrite: expansion too long");
695 						return;
696 					}
697 					*avp++ = *pp++;
698 				}
699 			}
700 			else
701 			{
702 				/* vanilla replacement */
703 				if (avp >= &npvp[MAXATOM])
704 				{
705 	toolong:
706 					syserr("rewrite: expansion too long");
707 					return;
708 				}
709 				*avp++ = rp;
710 			}
711 		}
712 		*avp++ = NULL;
713 
714 		/*
715 		**  Check for any hostname lookups.
716 		*/
717 
718 		for (rvp = npvp; *rvp != NULL; rvp++)
719 		{
720 			char **hbrvp;
721 			char **xpvp;
722 			int trsize;
723 			char *olddelimchar;
724 			char buf[MAXNAME + 1];
725 			char *pvpb1[MAXATOM + 1];
726 			char pvpbuf[PSBUFSIZE];
727 			extern char *DelimChar;
728 
729 			if (**rvp != HOSTBEGIN)
730 				continue;
731 
732 			/*
733 			**  Got a hostname lookup.
734 			**
735 			**	This could be optimized fairly easily.
736 			*/
737 
738 			hbrvp = rvp;
739 
740 			/* extract the match part */
741 			while (*++rvp != NULL && **rvp != HOSTEND)
742 				continue;
743 			if (*rvp != NULL)
744 				*rvp++ = NULL;
745 
746 			/* save the remainder of the input string */
747 			trsize = (int) (avp - rvp + 1) * sizeof *rvp;
748 			bcopy((char *) rvp, (char *) pvpb1, trsize);
749 
750 			/* look it up */
751 			cataddr(++hbrvp, buf, sizeof buf);
752 			maphostname(buf, sizeof buf);
753 
754 			/* scan the new host name */
755 			olddelimchar = DelimChar;
756 			xpvp = prescan(buf, '\0', pvpbuf);
757 			DelimChar = olddelimchar;
758 			if (xpvp == NULL)
759 			{
760 				syserr("rewrite: cannot prescan canonical hostname: %s", buf);
761 				return;
762 			}
763 
764 			/* append it to the token list */
765 			for (avp = --hbrvp; *xpvp != NULL; xpvp++)
766 			{
767 				*avp++ = newstr(*xpvp);
768 				if (avp >= &npvp[MAXATOM])
769 					goto toolong;
770 			}
771 
772 			/* restore the old trailing information */
773 			for (xpvp = pvpb1; (*avp++ = *xpvp++) != NULL; )
774 				if (avp >= &npvp[MAXATOM])
775 					goto toolong;
776 
777 			break;
778 		}
779 
780 		/*
781 		**  Check for subroutine calls.
782 		*/
783 
784 		if (*npvp != NULL && **npvp == CALLSUBR)
785 		{
786 			bcopy((char *) &npvp[2], (char *) pvp,
787 				(int) (avp - npvp - 2) * sizeof *avp);
788 			if (tTd(21, 3))
789 				printf("-----callsubr %s\n", npvp[1]);
790 			rewrite(pvp, atoi(npvp[1]));
791 		}
792 		else
793 		{
794 			bcopy((char *) npvp, (char *) pvp,
795 				(int) (avp - npvp) * sizeof *avp);
796 		}
797 		if (tTd(21, 4))
798 		{
799 			printf("rewritten as:");
800 			printav(pvp);
801 		}
802 	}
803 
804 	if (OpMode == MD_TEST || tTd(21, 2))
805 	{
806 		printf("rewrite: ruleset %2d returns:", ruleset);
807 		printav(pvp);
808 	}
809 }
810 /*
811 **  BUILDADDR -- build address from token vector.
812 **
813 **	Parameters:
814 **		tv -- token vector.
815 **		a -- pointer to address descriptor to fill.
816 **			If NULL, one will be allocated.
817 **
818 **	Returns:
819 **		NULL if there was an error.
820 **		'a' otherwise.
821 **
822 **	Side Effects:
823 **		fills in 'a'
824 */
825 
826 ADDRESS *
827 buildaddr(tv, a)
828 	register char **tv;
829 	register ADDRESS *a;
830 {
831 	static char buf[MAXNAME];
832 	struct mailer **mp;
833 	register struct mailer *m;
834 
835 	if (a == NULL)
836 		a = (ADDRESS *) xalloc(sizeof *a);
837 	bzero((char *) a, sizeof *a);
838 
839 	/* figure out what net/mailer to use */
840 	if (**tv != CANONNET)
841 	{
842 		syserr("buildaddr: no net");
843 		return (NULL);
844 	}
845 	tv++;
846 	if (!strcasecmp(*tv, "error"))
847 	{
848 		if (**++tv == CANONHOST)
849 		{
850 			setstat(atoi(*++tv));
851 			tv++;
852 		}
853 		if (**tv != CANONUSER)
854 			syserr("buildaddr: error: no user");
855 		buf[0] = '\0';
856 		while (*++tv != NULL)
857 		{
858 			if (buf[0] != '\0')
859 				(void) strcat(buf, " ");
860 			(void) strcat(buf, *tv);
861 		}
862 		usrerr(buf);
863 		return (NULL);
864 	}
865 	for (mp = Mailer; (m = *mp++) != NULL; )
866 	{
867 		if (!strcasecmp(m->m_name, *tv))
868 			break;
869 	}
870 	if (m == NULL)
871 	{
872 		syserr("buildaddr: unknown mailer %s", *tv);
873 		return (NULL);
874 	}
875 	a->q_mailer = m;
876 
877 	/* figure out what host (if any) */
878 	tv++;
879 	if (!bitnset(M_LOCAL, m->m_flags))
880 	{
881 		if (**tv++ != CANONHOST)
882 		{
883 			syserr("buildaddr: no host");
884 			return (NULL);
885 		}
886 		buf[0] = '\0';
887 		while (*tv != NULL && **tv != CANONUSER)
888 			(void) strcat(buf, *tv++);
889 		a->q_host = newstr(buf);
890 	}
891 	else
892 		a->q_host = NULL;
893 
894 	/* figure out the user */
895 	if (**tv != CANONUSER)
896 	{
897 		syserr("buildaddr: no user");
898 		return (NULL);
899 	}
900 
901 	/* rewrite according recipient mailer rewriting rules */
902 	rewrite(++tv, 2);
903 	if (m->m_r_rwset > 0)
904 		rewrite(tv, m->m_r_rwset);
905 	rewrite(tv, 4);
906 
907 	/* save the result for the command line/RCPT argument */
908 	cataddr(tv, buf, sizeof buf);
909 	a->q_user = buf;
910 
911 	return (a);
912 }
913 /*
914 **  CATADDR -- concatenate pieces of addresses (putting in <LWSP> subs)
915 **
916 **	Parameters:
917 **		pvp -- parameter vector to rebuild.
918 **		buf -- buffer to build the string into.
919 **		sz -- size of buf.
920 **
921 **	Returns:
922 **		none.
923 **
924 **	Side Effects:
925 **		Destroys buf.
926 */
927 
928 cataddr(pvp, buf, sz)
929 	char **pvp;
930 	char *buf;
931 	register int sz;
932 {
933 	bool oatomtok = FALSE;
934 	bool natomtok = FALSE;
935 	register int i;
936 	register char *p;
937 
938 	if (pvp == NULL)
939 	{
940 		(void) strcpy(buf, "");
941 		return;
942 	}
943 	p = buf;
944 	sz -= 2;
945 	while (*pvp != NULL && (i = strlen(*pvp)) < sz)
946 	{
947 		natomtok = (toktype(**pvp) == ATM);
948 		if (oatomtok && natomtok)
949 			*p++ = SpaceSub;
950 		(void) strcpy(p, *pvp);
951 		oatomtok = natomtok;
952 		p += i;
953 		sz -= i + 1;
954 		pvp++;
955 	}
956 	*p = '\0';
957 }
958 /*
959 **  SAMEADDR -- Determine if two addresses are the same
960 **
961 **	This is not just a straight comparison -- if the mailer doesn't
962 **	care about the host we just ignore it, etc.
963 **
964 **	Parameters:
965 **		a, b -- pointers to the internal forms to compare.
966 **
967 **	Returns:
968 **		TRUE -- they represent the same mailbox.
969 **		FALSE -- they don't.
970 **
971 **	Side Effects:
972 **		none.
973 */
974 
975 bool
976 sameaddr(a, b)
977 	register ADDRESS *a;
978 	register ADDRESS *b;
979 {
980 	/* if they don't have the same mailer, forget it */
981 	if (a->q_mailer != b->q_mailer)
982 		return (FALSE);
983 
984 	/* if the user isn't the same, we can drop out */
985 	if (strcmp(a->q_user, b->q_user) != 0)
986 		return (FALSE);
987 
988 	/* if the mailer ignores hosts, we have succeeded! */
989 	if (bitnset(M_LOCAL, a->q_mailer->m_flags))
990 		return (TRUE);
991 
992 	/* otherwise compare hosts (but be careful for NULL ptrs) */
993 	if (a->q_host == NULL || b->q_host == NULL)
994 		return (FALSE);
995 	if (strcmp(a->q_host, b->q_host) != 0)
996 		return (FALSE);
997 
998 	return (TRUE);
999 }
1000 /*
1001 **  PRINTADDR -- print address (for debugging)
1002 **
1003 **	Parameters:
1004 **		a -- the address to print
1005 **		follow -- follow the q_next chain.
1006 **
1007 **	Returns:
1008 **		none.
1009 **
1010 **	Side Effects:
1011 **		none.
1012 */
1013 
1014 printaddr(a, follow)
1015 	register ADDRESS *a;
1016 	bool follow;
1017 {
1018 	bool first = TRUE;
1019 
1020 	while (a != NULL)
1021 	{
1022 		first = FALSE;
1023 		printf("%x=", a);
1024 		(void) fflush(stdout);
1025 		printf("%s: mailer %d (%s), host `%s', user `%s'\n", a->q_paddr,
1026 		       a->q_mailer->m_mno, a->q_mailer->m_name, a->q_host,
1027 		       a->q_user);
1028 		printf("\tnext=%x, flags=%o, alias %x\n", a->q_next, a->q_flags,
1029 		       a->q_alias);
1030 		printf("\thome=\"%s\", fullname=\"%s\"\n", a->q_home,
1031 		       a->q_fullname);
1032 
1033 		if (!follow)
1034 			return;
1035 		a = a->q_next;
1036 	}
1037 	if (first)
1038 		printf("[NULL]\n");
1039 }
1040 
1041 /*
1042 **  REMOTENAME -- return the name relative to the current mailer
1043 **
1044 **	Parameters:
1045 **		name -- the name to translate.
1046 **		m -- the mailer that we want to do rewriting relative
1047 **			to.
1048 **		senderaddress -- if set, uses the sender rewriting rules
1049 **			rather than the recipient rewriting rules.
1050 **		canonical -- if set, strip out any comment information,
1051 **			etc.
1052 **
1053 **	Returns:
1054 **		the text string representing this address relative to
1055 **			the receiving mailer.
1056 **
1057 **	Side Effects:
1058 **		none.
1059 **
1060 **	Warnings:
1061 **		The text string returned is tucked away locally;
1062 **			copy it if you intend to save it.
1063 */
1064 
1065 char *
1066 remotename(name, m, senderaddress, canonical)
1067 	char *name;
1068 	struct mailer *m;
1069 	bool senderaddress;
1070 	bool canonical;
1071 {
1072 	register char **pvp;
1073 	char *fancy;
1074 	extern char *macvalue();
1075 	char *oldg = macvalue('g', CurEnv);
1076 	static char buf[MAXNAME];
1077 	char lbuf[MAXNAME];
1078 	char pvpbuf[PSBUFSIZE];
1079 	extern char **prescan();
1080 	extern char *crackaddr();
1081 
1082 	if (tTd(12, 1))
1083 		printf("remotename(%s)\n", name);
1084 
1085 	/* don't do anything if we are tagging it as special */
1086 	if ((senderaddress ? m->m_s_rwset : m->m_r_rwset) < 0)
1087 		return (name);
1088 
1089 	/*
1090 	**  Do a heuristic crack of this name to extract any comment info.
1091 	**	This will leave the name as a comment and a $g macro.
1092 	*/
1093 
1094 	if (canonical)
1095 		fancy = "\001g";
1096 	else
1097 		fancy = crackaddr(name);
1098 
1099 	/*
1100 	**  Turn the name into canonical form.
1101 	**	Normally this will be RFC 822 style, i.e., "user@domain".
1102 	**	If this only resolves to "user", and the "C" flag is
1103 	**	specified in the sending mailer, then the sender's
1104 	**	domain will be appended.
1105 	*/
1106 
1107 	pvp = prescan(name, '\0', pvpbuf);
1108 	if (pvp == NULL)
1109 		return (name);
1110 	rewrite(pvp, 3);
1111 	if (CurEnv->e_fromdomain != NULL)
1112 	{
1113 		/* append from domain to this address */
1114 		register char **pxp = pvp;
1115 
1116 		/* see if there is an "@domain" in the current name */
1117 		while (*pxp != NULL && strcmp(*pxp, "@") != 0)
1118 			pxp++;
1119 		if (*pxp == NULL)
1120 		{
1121 			/* no.... append the "@domain" from the sender */
1122 			register char **qxq = CurEnv->e_fromdomain;
1123 
1124 			while ((*pxp++ = *qxq++) != NULL)
1125 				continue;
1126 			rewrite(pvp, 3);
1127 		}
1128 	}
1129 
1130 	/*
1131 	**  Do more specific rewriting.
1132 	**	Rewrite using ruleset 1 or 2 depending on whether this is
1133 	**		a sender address or not.
1134 	**	Then run it through any receiving-mailer-specific rulesets.
1135 	*/
1136 
1137 	if (senderaddress)
1138 	{
1139 		rewrite(pvp, 1);
1140 		if (m->m_s_rwset > 0)
1141 			rewrite(pvp, m->m_s_rwset);
1142 	}
1143 	else
1144 	{
1145 		rewrite(pvp, 2);
1146 		if (m->m_r_rwset > 0)
1147 			rewrite(pvp, m->m_r_rwset);
1148 	}
1149 
1150 	/*
1151 	**  Do any final sanitation the address may require.
1152 	**	This will normally be used to turn internal forms
1153 	**	(e.g., user@host.LOCAL) into external form.  This
1154 	**	may be used as a default to the above rules.
1155 	*/
1156 
1157 	rewrite(pvp, 4);
1158 
1159 	/*
1160 	**  Now restore the comment information we had at the beginning.
1161 	*/
1162 
1163 	cataddr(pvp, lbuf, sizeof lbuf);
1164 	define('g', lbuf, CurEnv);
1165 	expand(fancy, buf, &buf[sizeof buf - 1], CurEnv);
1166 	define('g', oldg, CurEnv);
1167 
1168 	if (tTd(12, 1))
1169 		printf("remotename => `%s'\n", buf);
1170 	return (buf);
1171 }
1172