1 # include "sendmail.h"
2 
3 static char	SccsId[] = "@(#)parseaddr.c	3.20	08/25/81";
4 
5 /*
6 **  PARSE -- Parse an address
7 **
8 **	Parses an address and breaks it up into three parts: a
9 **	net to transmit the message on, the host to transmit it
10 **	to, and a user on that host.  These are loaded into an
11 **	ADDRESS header with the values squirreled away if necessary.
12 **	The "user" part may not be a real user; the process may
13 **	just reoccur on that machine.  For example, on a machine
14 **	with an arpanet connection, the address
15 **		csvax.bill@berkeley
16 **	will break up to a "user" of 'csvax.bill' and a host
17 **	of 'berkeley' -- to be transmitted over the arpanet.
18 **
19 **	Parameters:
20 **		addr -- the address to parse.
21 **		a -- a pointer to the address descriptor buffer.
22 **			If NULL, a header will be created.
23 **		copyf -- determines what shall be copied:
24 **			-1 -- don't copy anything.  The printname
25 **				(q_paddr) is just addr, and the
26 **				user & host are allocated internally
27 **				to parse.
28 **			0 -- copy out the parsed user & host, but
29 **				don't copy the printname.
30 **			+1 -- copy everything.
31 **
32 **	Returns:
33 **		A pointer to the address descriptor header (`a' if
34 **			`a' is non-NULL).
35 **		NULL on error.
36 **
37 **	Side Effects:
38 **		none
39 */
40 
41 # define DELIMCHARS	"$()<>,;\\\"\r\n"	/* word delimiters */
42 # define SPACESUB	('.'|0200)		/* substitution for <lwsp> */
43 
44 ADDRESS *
45 parse(addr, a, copyf)
46 	char *addr;
47 	register ADDRESS *a;
48 	int copyf;
49 {
50 	register char **pvp;
51 	register struct mailer *m;
52 	extern char **prescan();
53 	extern ADDRESS *buildaddr();
54 
55 	/*
56 	**  Initialize and prescan address.
57 	*/
58 
59 	To = addr;
60 # ifdef DEBUG
61 	if (Debug)
62 		printf("\n--parse(%s)\n", addr);
63 # endif DEBUG
64 
65 	pvp = prescan(addr, '\0');
66 	if (pvp == NULL)
67 		return (NULL);
68 
69 	/*
70 	**  Apply rewriting rules.
71 	*/
72 
73 	rewrite(pvp, 0);
74 
75 	/*
76 	**  See if we resolved to a real mailer.
77 	*/
78 
79 	if (pvp[0][0] != CANONNET)
80 	{
81 		setstat(EX_USAGE);
82 		usrerr("cannot resolve name");
83 		return (NULL);
84 	}
85 
86 	/*
87 	**  Build canonical address from pvp.
88 	*/
89 
90 	a = buildaddr(pvp, a);
91 	m = Mailer[a->q_mailer];
92 
93 	/*
94 	**  Make local copies of the host & user and then
95 	**  transport them out.
96 	*/
97 
98 	if (copyf > 0)
99 		a->q_paddr = newstr(addr);
100 	else
101 		a->q_paddr = addr;
102 
103 	if (copyf >= 0)
104 	{
105 		if (a->q_host != NULL)
106 			a->q_host = newstr(a->q_host);
107 		else
108 			a->q_host = "";
109 		if (a->q_user != a->q_paddr)
110 			a->q_user = newstr(a->q_user);
111 	}
112 
113 	/*
114 	**  Do UPPER->lower case mapping unless inhibited.
115 	*/
116 
117 	if (!bitset(M_HST_UPPER, m->m_flags))
118 		makelower(a->q_host);
119 	if (!bitset(M_USR_UPPER, m->m_flags))
120 		makelower(a->q_user);
121 
122 	/*
123 	**  Compute return value.
124 	*/
125 
126 # ifdef DEBUG
127 	if (Debug)
128 		printf("parse(\"%s\"): host \"%s\" user \"%s\" mailer %d\n",
129 		    addr, a->q_host, a->q_user, a->q_mailer);
130 # endif DEBUG
131 
132 	return (a);
133 }
134 /*
135 **  PRESCAN -- Prescan name and make it canonical
136 **
137 **	Scans a name and turns it into canonical form.  This involves
138 **	deleting blanks, comments (in parentheses), and turning the
139 **	word "at" into an at-sign ("@").  The name is copied as this
140 **	is done; it is legal to copy a name onto itself, since this
141 **	process can only make things smaller.
142 **
143 **	This routine knows about quoted strings and angle brackets.
144 **
145 **	There are certain subtleties to this routine.  The one that
146 **	comes to mind now is that backslashes on the ends of names
147 **	are silently stripped off; this is intentional.  The problem
148 **	is that some versions of sndmsg (like at LBL) set the kill
149 **	character to something other than @ when reading addresses;
150 **	so people type "csvax.eric\@berkeley" -- which screws up the
151 **	berknet mailer.
152 **
153 **	Parameters:
154 **		addr -- the name to chomp.
155 **		delim -- the delimiter for the address, normally
156 **			'\0' or ','; \0 is accepted in any case.
157 **			are moving in place; set buflim to high core.
158 **
159 **	Returns:
160 **		A pointer to a vector of tokens.
161 **		NULL on error.
162 **
163 **	Side Effects:
164 **		none.
165 */
166 
167 # define OPER		1
168 # define ATOM		2
169 # define EOTOK		3
170 # define QSTRING	4
171 # define SPACE		5
172 # define DOLLAR		6
173 # define GETONE		7
174 
175 char **
176 prescan(addr, delim)
177 	char *addr;
178 	char delim;
179 {
180 	register char *p;
181 	static char buf[MAXNAME+MAXATOM];
182 	static char *av[MAXATOM+1];
183 	char **avp;
184 	bool space;
185 	bool bslashmode;
186 	int cmntcnt;
187 	int brccnt;
188 	register char c;
189 	char *tok;
190 	register char *q;
191 	register int state;
192 	int nstate;
193 	extern char lower();
194 
195 	space = FALSE;
196 	q = buf;
197 	bslashmode = FALSE;
198 	cmntcnt = brccnt = 0;
199 	avp = av;
200 	state = OPER;
201 	for (p = addr; *p != '\0' && *p != delim; )
202 	{
203 		/* read a token */
204 		tok = q;
205 		while ((c = *p++) != '\0' && c != delim)
206 		{
207 			/* chew up special characters */
208 			c &= ~0200;
209 			*q = '\0';
210 			if (bslashmode)
211 			{
212 				c |= 0200;
213 				bslashmode = FALSE;
214 			}
215 			else if (c == '\\')
216 			{
217 				bslashmode = TRUE;
218 				continue;
219 			}
220 			else if (c == '"')
221 			{
222 				if (state == QSTRING)
223 					state = OPER;
224 				else
225 					state = QSTRING;
226 				break;
227 			}
228 
229 			nstate = toktype(c);
230 			switch (state)
231 			{
232 			  case QSTRING:		/* in quoted string */
233 				break;
234 
235 			  case ATOM:		/* regular atom */
236 				/* state = nstate; */
237 				if (nstate != ATOM)
238 				{
239 					state = EOTOK;
240 					p--;
241 				}
242 				break;
243 
244 			  case GETONE:		/* grab one character */
245 				state = OPER;
246 				break;
247 
248 			  case EOTOK:		/* after atom or q-string */
249 				state = nstate;
250 				if (state == SPACE)
251 					continue;
252 				break;
253 
254 			  case SPACE:		/* linear white space */
255 				state = nstate;
256 				space = TRUE;
257 				break;
258 
259 			  case OPER:		/* operator */
260 				if (nstate == SPACE)
261 					continue;
262 				state = nstate;
263 				break;
264 
265 			  case DOLLAR:		/* $- etc. */
266 				state = OPER;
267 				switch (c)
268 				{
269 				  case '$':		/* literal $ */
270 					break;
271 
272 				  case '+':		/* match anything */
273 					c = MATCHANY;
274 					state = GETONE;
275 					break;
276 
277 				  case '-':		/* match one token */
278 					c = MATCHONE;
279 					state = GETONE;
280 					break;
281 
282 				  case '=':		/* match one token of class */
283 					c = MATCHCLASS;
284 					state = GETONE;
285 					break;
286 
287 				  case '#':		/* canonical net name */
288 					c = CANONNET;
289 					break;
290 
291 				  case '@':		/* canonical host name */
292 					c = CANONHOST;
293 					break;
294 
295 				  case ':':		/* canonical user name */
296 					c = CANONUSER;
297 					break;
298 
299 				  default:
300 					c = '$';
301 					state = OPER;
302 					p--;
303 					break;
304 				}
305 				break;
306 
307 			  default:
308 				syserr("prescan: unknown state %d", state);
309 			}
310 
311 			if (state == EOTOK || state == SPACE)
312 				break;
313 			if (c == '$' && delim == '\t')
314 			{
315 				state = DOLLAR;
316 				continue;
317 			}
318 
319 			/* squirrel it away */
320 			if (q >= &buf[sizeof buf - 5])
321 			{
322 				usrerr("Address too long");
323 				return (NULL);
324 			}
325 			*q++ = c;
326 
327 			/* decide whether this represents end of token */
328 			if (state == OPER)
329 				break;
330 		}
331 		if (c == '\0' || c == delim)
332 			p--;
333 
334 		/* new token */
335 		if (tok == q)
336 			continue;
337 		*q++ = '\0';
338 
339 		c = tok[0];
340 		if (c == '(')
341 		{
342 			cmntcnt++;
343 			continue;
344 		}
345 		else if (c == ')')
346 		{
347 			if (cmntcnt <= 0)
348 			{
349 				usrerr("Unbalanced ')'");
350 				return (NULL);
351 			}
352 			else
353 			{
354 				cmntcnt--;
355 				continue;
356 			}
357 		}
358 		else if (cmntcnt > 0)
359 			continue;
360 
361 		*avp++ = tok;
362 
363 		/* we prefer <> specs */
364 		if (c == '<')
365 		{
366 			if (brccnt < 0)
367 			{
368 				usrerr("multiple < spec");
369 				return (NULL);
370 			}
371 			brccnt++;
372 			space = FALSE;
373 			if (brccnt == 1)
374 			{
375 				/* we prefer using machine readable name */
376 				q = buf;
377 				*q = '\0';
378 				avp = av;
379 				continue;
380 			}
381 		}
382 		else if (c == '>')
383 		{
384 			if (brccnt <= 0)
385 			{
386 				usrerr("Unbalanced `>'");
387 				return (NULL);
388 			}
389 			else
390 				brccnt--;
391 			if (brccnt <= 0)
392 			{
393 				brccnt = -1;
394 				continue;
395 			}
396 		}
397 
398 		/*
399 		**  Turn "at" into "@",
400 		**	but only if "at" is a word.
401 		*/
402 
403 		if (lower(tok[0]) == 'a' && lower(tok[1]) == 't' && tok[2] == '\0')
404 		{
405 			tok[0] = '@';
406 			tok[1] = '\0';
407 		}
408 	}
409 	*avp = NULL;
410 	if (cmntcnt > 0)
411 		usrerr("Unbalanced '('");
412 	else if (brccnt > 0)
413 		usrerr("Unbalanced '<'");
414 	else if (state == QSTRING)
415 		usrerr("Unbalanced '\"'");
416 	else if (av[0] != NULL)
417 		return (av);
418 	return (NULL);
419 }
420 /*
421 **  TOKTYPE -- return token type
422 **
423 **	Parameters:
424 **		c -- the character in question.
425 **
426 **	Returns:
427 **		Its type.
428 **
429 **	Side Effects:
430 **		none.
431 */
432 
433 toktype(c)
434 	register char c;
435 {
436 	static char buf[50];
437 	static bool firstime = TRUE;
438 
439 	if (firstime)
440 	{
441 		firstime = FALSE;
442 		(void) expand("$o", buf, &buf[sizeof buf - 1]);
443 		strcat(buf, DELIMCHARS);
444 	}
445 	if (!isascii(c))
446 		return (ATOM);
447 	if (isspace(c))
448 		return (SPACE);
449 	if (iscntrl(c) || index(buf, c) != NULL)
450 		return (OPER);
451 	return (ATOM);
452 }
453 /*
454 **  REWRITE -- apply rewrite rules to token vector.
455 **
456 **	Parameters:
457 **		pvp -- pointer to token vector.
458 **
459 **	Returns:
460 **		none.
461 **
462 **	Side Effects:
463 **		pvp is modified.
464 */
465 
466 struct match
467 {
468 	char	**firsttok;	/* first token matched */
469 	char	**lasttok;	/* last token matched */
470 	char	name;		/* name of parameter */
471 };
472 
473 # define MAXMATCH	8	/* max params per rewrite */
474 
475 
476 rewrite(pvp, ruleset)
477 	char **pvp;
478 	int ruleset;
479 {
480 	register char *ap;		/* address pointer */
481 	register char *rp;		/* rewrite pointer */
482 	register char **avp;		/* address vector pointer */
483 	register char **rvp;		/* rewrite vector pointer */
484 	struct rewrite *rwr;
485 	struct match mlist[MAXMATCH];
486 	char *npvp[MAXATOM+1];		/* temporary space for rebuild */
487 	extern bool sameword();
488 
489 # ifdef DEBUG
490 	if (Debug > 9)
491 	{
492 		printf("rewrite: original pvp:\n");
493 		printav(pvp);
494 	}
495 # endif DEBUG
496 
497 	/*
498 	**  Run through the list of rewrite rules, applying
499 	**	any that match.
500 	*/
501 
502 	for (rwr = RewriteRules[ruleset]; rwr != NULL; )
503 	{
504 # ifdef DEBUG
505 		if (Debug > 10)
506 		{
507 			printf("-----trying rule:\n");
508 			printav(rwr->r_lhs);
509 		}
510 # endif DEBUG
511 
512 		/* try to match on this rule */
513 		clrmatch(mlist);
514 		for (rvp = rwr->r_lhs, avp = pvp; *avp != NULL; )
515 		{
516 			ap = *avp;
517 			rp = *rvp;
518 
519 			if (rp == NULL)
520 			{
521 				/* end-of-pattern before end-of-address */
522 				goto fail;
523 			}
524 
525 			switch (*rp)
526 			{
527 				register STAB *s;
528 				register int class;
529 
530 			  case MATCHONE:
531 				/* match exactly one token */
532 				setmatch(mlist, rp[1], avp, avp);
533 				break;
534 
535 			  case MATCHANY:
536 				/* match any number of tokens */
537 				setmatch(mlist, rp[1], (char **) NULL, avp);
538 				break;
539 
540 			  case MATCHCLASS:
541 				/* match any token in a class */
542 				class = rp[1];
543 				if (!isalpha(class))
544 					goto fail;
545 				if (isupper(class))
546 					class -= 'A';
547 				else
548 					class -= 'a';
549 				s = stab(ap, ST_CLASS, ST_FIND);
550 				if (s == NULL || (s->s_class & (1 << class)) == 0)
551 					goto fail;
552 				break;
553 
554 			  default:
555 				/* must have exact match */
556 				if (!sameword(rp, ap))
557 					goto fail;
558 				break;
559 			}
560 
561 			/* successful match on this token */
562 			avp++;
563 			rvp++;
564 			continue;
565 
566 		  fail:
567 			/* match failed -- back up */
568 			while (--rvp >= rwr->r_lhs)
569 			{
570 				rp = *rvp;
571 				if (*rp == MATCHANY)
572 					break;
573 
574 				/* can't extend match: back up everything */
575 				avp--;
576 
577 				if (*rp == MATCHONE)
578 				{
579 					/* undo binding */
580 					setmatch(mlist, rp[1], (char **) NULL, (char **) NULL);
581 				}
582 			}
583 
584 			if (rvp < rwr->r_lhs)
585 			{
586 				/* total failure to match */
587 				break;
588 			}
589 		}
590 
591 		/*
592 		**  See if we successfully matched
593 		*/
594 
595 		if (rvp >= rwr->r_lhs && *rvp == NULL)
596 		{
597 # ifdef DEBUG
598 			if (Debug > 10)
599 			{
600 				printf("-----rule matches:\n");
601 				printav(rwr->r_rhs);
602 			}
603 # endif DEBUG
604 
605 			/* substitute */
606 			for (rvp = rwr->r_rhs, avp = npvp; *rvp != NULL; rvp++)
607 			{
608 				rp = *rvp;
609 				if (*rp == MATCHANY)
610 				{
611 					register struct match *m;
612 					register char **pp;
613 					extern struct match *findmatch();
614 
615 					m = findmatch(mlist, rp[1]);
616 					if (m != NULL)
617 					{
618 						pp = m->firsttok;
619 						do
620 						{
621 							*avp++ = *pp;
622 						} while (pp++ != m->lasttok);
623 					}
624 				}
625 				else
626 					*avp++ = rp;
627 			}
628 			*avp++ = NULL;
629 			bmove((char *) npvp, (char *) pvp, (avp - npvp) * sizeof *avp);
630 # ifdef DEBUG
631 			if (Debug > 3)
632 			{
633 				char **vp;
634 
635 				printf("rewritten as `");
636 				for (vp = pvp; *vp != NULL; vp++)
637 				{
638 					if (vp != pvp)
639 						printf("_");
640 					xputs(*vp);
641 				}
642 				printf("'\n");
643 			}
644 # endif DEBUG
645 			if (pvp[0][0] == CANONNET)
646 				break;
647 		}
648 		else
649 		{
650 # ifdef DEBUG
651 			if (Debug > 10)
652 				printf("----- rule fails\n");
653 # endif DEBUG
654 			rwr = rwr->r_next;
655 		}
656 	}
657 }
658 /*
659 **  SETMATCH -- set parameter value in match vector
660 **
661 **	Parameters:
662 **		mlist -- list of match values.
663 **		name -- the character name of this parameter.
664 **		first -- the first location of the replacement.
665 **		last -- the last location of the replacement.
666 **
667 **		If last == NULL, delete this entry.
668 **		If first == NULL, extend this entry (or add it if
669 **			it does not exist).
670 **
671 **	Returns:
672 **		nothing.
673 **
674 **	Side Effects:
675 **		munges with mlist.
676 */
677 
678 setmatch(mlist, name, first, last)
679 	struct match *mlist;
680 	char name;
681 	char **first;
682 	char **last;
683 {
684 	register struct match *m;
685 	struct match *nullm = NULL;
686 
687 	for (m = mlist; m < &mlist[MAXMATCH]; m++)
688 	{
689 		if (m->name == name)
690 			break;
691 		if (m->name == '\0')
692 			nullm = m;
693 	}
694 
695 	if (m >= &mlist[MAXMATCH])
696 		m = nullm;
697 
698 	if (last == NULL)
699 	{
700 		m->name = '\0';
701 		return;
702 	}
703 
704 	if (m->name == '\0')
705 	{
706 		if (first == NULL)
707 			m->firsttok = last;
708 		else
709 			m->firsttok = first;
710 	}
711 	m->name = name;
712 	m->lasttok = last;
713 }
714 /*
715 **  FINDMATCH -- find match in mlist
716 **
717 **	Parameters:
718 **		mlist -- list to search.
719 **		name -- name to find.
720 **
721 **	Returns:
722 **		pointer to match structure.
723 **		NULL if no match.
724 **
725 **	Side Effects:
726 **		none.
727 */
728 
729 struct match *
730 findmatch(mlist, name)
731 	struct match *mlist;
732 	char name;
733 {
734 	register struct match *m;
735 
736 	for (m = mlist; m < &mlist[MAXMATCH]; m++)
737 	{
738 		if (m->name == name)
739 			return (m);
740 	}
741 
742 	return (NULL);
743 }
744 /*
745 **  CLRMATCH -- clear match list
746 **
747 **	Parameters:
748 **		mlist -- list to clear.
749 **
750 **	Returns:
751 **		none.
752 **
753 **	Side Effects:
754 **		mlist is cleared.
755 */
756 
757 clrmatch(mlist)
758 	struct match *mlist;
759 {
760 	register struct match *m;
761 
762 	for (m = mlist; m < &mlist[MAXMATCH]; m++)
763 		m->name = '\0';
764 }
765 /*
766 **  BUILDADDR -- build address from token vector.
767 **
768 **	Parameters:
769 **		tv -- token vector.
770 **		a -- pointer to address descriptor to fill.
771 **			If NULL, one will be allocated.
772 **
773 **	Returns:
774 **		'a'
775 **
776 **	Side Effects:
777 **		fills in 'a'
778 */
779 
780 ADDRESS *
781 buildaddr(tv, a)
782 	register char **tv;
783 	register ADDRESS *a;
784 {
785 	register int i;
786 	static char buf[MAXNAME];
787 	struct mailer **mp;
788 	register struct mailer *m;
789 
790 	if (a == NULL)
791 		a = (ADDRESS *) xalloc(sizeof *a);
792 	a->q_flags = 0;
793 	a->q_home = NULL;
794 
795 	/* figure out what net/mailer to use */
796 	if (**tv != CANONNET)
797 		syserr("buildaddr: no net");
798 	tv++;
799 	for (mp = Mailer, i = 0; (m = *mp++) != NULL; i++)
800 	{
801 		if (strcmp(m->m_name, *tv) == 0)
802 			break;
803 	}
804 	if (m == NULL)
805 		syserr("buildaddr: unknown net %s", *tv);
806 	a->q_mailer = i;
807 
808 	/* figure out what host (if any) */
809 	tv++;
810 	if (!bitset(M_LOCAL, m->m_flags))
811 	{
812 		if (**tv != CANONHOST)
813 			syserr("buildaddr: no host");
814 		tv++;
815 		a->q_host = *tv;
816 		tv++;
817 	}
818 	else
819 		a->q_host = NULL;
820 
821 	/* figure out the user */
822 	if (**tv != CANONUSER)
823 		syserr("buildaddr: no user");
824 	cataddr(++tv, buf, sizeof buf);
825 	a->q_user = buf;
826 
827 	return (a);
828 }
829 /*
830 **  CATADDR -- concatenate pieces of addresses (putting in <LWSP> subs)
831 **
832 **	Parameters:
833 **		pvp -- parameter vector to rebuild.
834 **		buf -- buffer to build the string into.
835 **		sz -- size of buf.
836 **
837 **	Returns:
838 **		none.
839 **
840 **	Side Effects:
841 **		Destroys buf.
842 */
843 
844 cataddr(pvp, buf, sz)
845 	char **pvp;
846 	char *buf;
847 	register int sz;
848 {
849 	bool oatomtok = FALSE;
850 	bool natomtok = FALSE;
851 	register int i;
852 	register char *p;
853 
854 	p = buf;
855 	sz--;
856 	while (*pvp != NULL && (i = strlen(*pvp)) < sz)
857 	{
858 		natomtok = (toktype(**pvp) == ATOM);
859 		if (oatomtok && natomtok)
860 			*p++ = SPACESUB;
861 		(void) strcpy(p, *pvp);
862 		oatomtok = natomtok;
863 		p += i;
864 		sz -= i;
865 		pvp++;
866 	}
867 	*p = '\0';
868 }
869 /*
870 **  SAMEADDR -- Determine if two addresses are the same
871 **
872 **	This is not just a straight comparison -- if the mailer doesn't
873 **	care about the host we just ignore it, etc.
874 **
875 **	Parameters:
876 **		a, b -- pointers to the internal forms to compare.
877 **		wildflg -- if TRUE, 'a' may have no user specified,
878 **			in which case it is to match anything.
879 **
880 **	Returns:
881 **		TRUE -- they represent the same mailbox.
882 **		FALSE -- they don't.
883 **
884 **	Side Effects:
885 **		none.
886 */
887 
888 bool
889 sameaddr(a, b, wildflg)
890 	register ADDRESS *a;
891 	register ADDRESS *b;
892 	bool wildflg;
893 {
894 	/* if they don't have the same mailer, forget it */
895 	if (a->q_mailer != b->q_mailer)
896 		return (FALSE);
897 
898 	/* if the user isn't the same, we can drop out */
899 	if ((!wildflg || a->q_user[0] != '\0') && strcmp(a->q_user, b->q_user) != 0)
900 		return (FALSE);
901 
902 	/* if the mailer ignores hosts, we have succeeded! */
903 	if (bitset(M_LOCAL, Mailer[a->q_mailer]->m_flags))
904 		return (TRUE);
905 
906 	/* otherwise compare hosts (but be careful for NULL ptrs) */
907 	if (a->q_host == NULL || b->q_host == NULL)
908 		return (FALSE);
909 	if (strcmp(a->q_host, b->q_host) != 0)
910 		return (FALSE);
911 
912 	return (TRUE);
913 }
914 /*
915 **  PRINTADDR -- print address (for debugging)
916 **
917 **	Parameters:
918 **		a -- the address to print
919 **		follow -- follow the q_next chain.
920 **
921 **	Returns:
922 **		none.
923 **
924 **	Side Effects:
925 **		none.
926 */
927 
928 printaddr(a, follow)
929 	register ADDRESS *a;
930 	bool follow;
931 {
932 	while (a != NULL)
933 	{
934 		printf("addr@%x: ", a);
935 		(void) fflush(stdout);
936 		printf("%s: mailer %d (%s), host `%s', user `%s'\n", a->q_paddr,
937 		       a->q_mailer, Mailer[a->q_mailer]->m_name, a->q_host, a->q_user);
938 		printf("\tnext=%x flags=%o, rmailer %d\n", a->q_next,
939 		       a->q_flags, a->q_rmailer);
940 
941 		if (!follow)
942 			return;
943 		a = a->q_next;
944 	}
945 }
946