xref: /titanic_50/usr/src/cmd/sendmail/src/mci.c (revision d291d9f21e8c0417aec99de243dd48bc400002d0)
1 /*
2  * Copyright (c) 1998-2005 Sendmail, Inc. and its suppliers.
3  *	All rights reserved.
4  * Copyright (c) 1995-1997 Eric P. Allman.  All rights reserved.
5  * Copyright (c) 1988, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * By using this file, you agree to the terms and conditions set
9  * forth in the LICENSE file which can be found at the top level of
10  * the sendmail distribution.
11  *
12  */
13 
14 #pragma ident	"%Z%%M%	%I%	%E% SMI"
15 
16 #include <sendmail.h>
17 
18 SM_RCSID("@(#)$Id: mci.c,v 8.216 2005/07/12 22:27:44 ca Exp $")
19 
20 #if NETINET || NETINET6
21 # include <arpa/inet.h>
22 #endif /* NETINET || NETINET6 */
23 
24 #include <dirent.h>
25 
26 static int	mci_generate_persistent_path __P((const char *, char *,
27 						  int, bool));
28 static bool	mci_load_persistent __P((MCI *));
29 static void	mci_uncache __P((MCI **, bool));
30 static int	mci_lock_host_statfile __P((MCI *));
31 static int	mci_read_persistent __P((SM_FILE_T *, MCI *));
32 
33 /*
34 **  Mail Connection Information (MCI) Caching Module.
35 **
36 **	There are actually two separate things cached.  The first is
37 **	the set of all open connections -- these are stored in a
38 **	(small) list.  The second is stored in the symbol table; it
39 **	has the overall status for all hosts, whether or not there
40 **	is a connection open currently.
41 **
42 **	There should never be too many connections open (since this
43 **	could flood the socket table), nor should a connection be
44 **	allowed to sit idly for too long.
45 **
46 **	MaxMciCache is the maximum number of open connections that
47 **	will be supported.
48 **
49 **	MciCacheTimeout is the time (in seconds) that a connection
50 **	is permitted to survive without activity.
51 **
52 **	We actually try any cached connections by sending a RSET
53 **	before we use them; if the RSET fails we close down the
54 **	connection and reopen it (see smtpprobe()).
55 **
56 **	The persistent MCI code is donated by Mark Lovell and Paul
57 **	Vixie.  It is based on the long term host status code in KJS
58 **	written by Paul but has been adapted by Mark to fit into the
59 **	MCI structure.
60 */
61 
62 static MCI	**MciCache;		/* the open connection cache */
63 
64 /*
65 **  MCI_CACHE -- enter a connection structure into the open connection cache
66 **
67 **	This may cause something else to be flushed.
68 **
69 **	Parameters:
70 **		mci -- the connection to cache.
71 **
72 **	Returns:
73 **		none.
74 */
75 
76 void
77 mci_cache(mci)
78 	register MCI *mci;
79 {
80 	register MCI **mcislot;
81 
82 	/*
83 	**  Find the best slot.  This may cause expired connections
84 	**  to be closed.
85 	*/
86 
87 	mcislot = mci_scan(mci);
88 	if (mcislot == NULL)
89 	{
90 		/* we don't support caching */
91 		return;
92 	}
93 
94 	if (mci->mci_host == NULL)
95 		return;
96 
97 	/* if this is already cached, we are done */
98 	if (bitset(MCIF_CACHED, mci->mci_flags))
99 		return;
100 
101 	/* otherwise we may have to clear the slot */
102 	if (*mcislot != NULL)
103 		mci_uncache(mcislot, true);
104 
105 	if (tTd(42, 5))
106 		sm_dprintf("mci_cache: caching %p (%s) in slot %d\n",
107 			   mci, mci->mci_host, (int) (mcislot - MciCache));
108 	if (tTd(91, 100))
109 		sm_syslog(LOG_DEBUG, CurEnv->e_id,
110 			  "mci_cache: caching %lx (%.100s) in slot %d",
111 			  (unsigned long) mci, mci->mci_host,
112 			  (int) (mcislot - MciCache));
113 
114 	*mcislot = mci;
115 	mci->mci_flags |= MCIF_CACHED;
116 }
117 /*
118 **  MCI_SCAN -- scan the cache, flush junk, and return best slot
119 **
120 **	Parameters:
121 **		savemci -- never flush this one.  Can be null.
122 **
123 **	Returns:
124 **		The LRU (or empty) slot.
125 */
126 
127 MCI **
128 mci_scan(savemci)
129 	MCI *savemci;
130 {
131 	time_t now;
132 	register MCI **bestmci;
133 	register MCI *mci;
134 	register int i;
135 
136 	if (MaxMciCache <= 0)
137 	{
138 		/* we don't support caching */
139 		return NULL;
140 	}
141 
142 	if (MciCache == NULL)
143 	{
144 		/* first call */
145 		MciCache = (MCI **) sm_pmalloc_x(MaxMciCache * sizeof *MciCache);
146 		memset((char *) MciCache, '\0', MaxMciCache * sizeof *MciCache);
147 		return &MciCache[0];
148 	}
149 
150 	now = curtime();
151 	bestmci = &MciCache[0];
152 	for (i = 0; i < MaxMciCache; i++)
153 	{
154 		mci = MciCache[i];
155 		if (mci == NULL || mci->mci_state == MCIS_CLOSED)
156 		{
157 			bestmci = &MciCache[i];
158 			continue;
159 		}
160 		if ((mci->mci_lastuse + MciCacheTimeout <= now ||
161 		     (mci->mci_mailer != NULL &&
162 		      mci->mci_mailer->m_maxdeliveries > 0 &&
163 		      mci->mci_deliveries + 1 >= mci->mci_mailer->m_maxdeliveries))&&
164 		    mci != savemci)
165 		{
166 			/* connection idle too long or too many deliveries */
167 			bestmci = &MciCache[i];
168 
169 			/* close it */
170 			mci_uncache(bestmci, true);
171 			continue;
172 		}
173 		if (*bestmci == NULL)
174 			continue;
175 		if (mci->mci_lastuse < (*bestmci)->mci_lastuse)
176 			bestmci = &MciCache[i];
177 	}
178 	return bestmci;
179 }
180 /*
181 **  MCI_UNCACHE -- remove a connection from a slot.
182 **
183 **	May close a connection.
184 **
185 **	Parameters:
186 **		mcislot -- the slot to empty.
187 **		doquit -- if true, send QUIT protocol on this connection.
188 **			  if false, we are assumed to be in a forked child;
189 **				all we want to do is close the file(s).
190 **
191 **	Returns:
192 **		none.
193 */
194 
195 static void
196 mci_uncache(mcislot, doquit)
197 	register MCI **mcislot;
198 	bool doquit;
199 {
200 	register MCI *mci;
201 	extern ENVELOPE BlankEnvelope;
202 
203 	mci = *mcislot;
204 	if (mci == NULL)
205 		return;
206 	*mcislot = NULL;
207 	if (mci->mci_host == NULL)
208 		return;
209 
210 	mci_unlock_host(mci);
211 
212 	if (tTd(42, 5))
213 		sm_dprintf("mci_uncache: uncaching %p (%s) from slot %d (%d)\n",
214 			   mci, mci->mci_host, (int) (mcislot - MciCache),
215 			   doquit);
216 	if (tTd(91, 100))
217 		sm_syslog(LOG_DEBUG, CurEnv->e_id,
218 			  "mci_uncache: uncaching %lx (%.100s) from slot %d (%d)",
219 			  (unsigned long) mci, mci->mci_host,
220 			  (int) (mcislot - MciCache), doquit);
221 
222 	mci->mci_deliveries = 0;
223 	if (doquit)
224 	{
225 		message("Closing connection to %s", mci->mci_host);
226 
227 		mci->mci_flags &= ~MCIF_CACHED;
228 
229 		/* only uses the envelope to flush the transcript file */
230 		if (mci->mci_state != MCIS_CLOSED)
231 			smtpquit(mci->mci_mailer, mci, &BlankEnvelope);
232 #if XLA
233 		xla_host_end(mci->mci_host);
234 #endif /* XLA */
235 	}
236 	else
237 	{
238 		if (mci->mci_in != NULL)
239 			(void) sm_io_close(mci->mci_in, SM_TIME_DEFAULT);
240 		if (mci->mci_out != NULL)
241 			(void) sm_io_close(mci->mci_out, SM_TIME_DEFAULT);
242 		mci->mci_in = mci->mci_out = NULL;
243 		mci->mci_state = MCIS_CLOSED;
244 		mci->mci_exitstat = EX_OK;
245 		mci->mci_errno = 0;
246 		mci->mci_flags = 0;
247 
248 		mci->mci_retryrcpt = false;
249 		mci->mci_tolist = NULL;
250 #if PIPELINING
251 		mci->mci_okrcpts = 0;
252 #endif /* PIPELINING */
253 	}
254 
255 	SM_FREE_CLR(mci->mci_status);
256 	SM_FREE_CLR(mci->mci_rstatus);
257 	SM_FREE_CLR(mci->mci_heloname);
258 	if (mci->mci_rpool != NULL)
259 	{
260 		sm_rpool_free(mci->mci_rpool);
261 		mci->mci_macro.mac_rpool = NULL;
262 		mci->mci_rpool = NULL;
263 	}
264 }
265 /*
266 **  MCI_FLUSH -- flush the entire cache
267 **
268 **	Parameters:
269 **		doquit -- if true, send QUIT protocol.
270 **			  if false, just close the connection.
271 **		allbut -- but leave this one open.
272 **
273 **	Returns:
274 **		none.
275 */
276 
277 void
278 mci_flush(doquit, allbut)
279 	bool doquit;
280 	MCI *allbut;
281 {
282 	register int i;
283 
284 	if (MciCache == NULL)
285 		return;
286 
287 	for (i = 0; i < MaxMciCache; i++)
288 	{
289 		if (allbut != MciCache[i])
290 			mci_uncache(&MciCache[i], doquit);
291 	}
292 }
293 /*
294 **  MCI_GET -- get information about a particular host
295 **
296 **	Parameters:
297 **		host -- host to look for.
298 **		m -- mailer.
299 **
300 **	Returns:
301 **		mci for this host (might be new).
302 */
303 
304 MCI *
305 mci_get(host, m)
306 	char *host;
307 	MAILER *m;
308 {
309 	register MCI *mci;
310 	register STAB *s;
311 	extern SOCKADDR CurHostAddr;
312 
313 	/* clear CurHostAddr so we don't get a bogus address with this name */
314 	memset(&CurHostAddr, '\0', sizeof CurHostAddr);
315 
316 	/* clear out any expired connections */
317 	(void) mci_scan(NULL);
318 
319 	if (m->m_mno < 0)
320 		syserr("!negative mno %d (%s)", m->m_mno, m->m_name);
321 
322 	s = stab(host, ST_MCI + m->m_mno, ST_ENTER);
323 	mci = &s->s_mci;
324 
325 	/* initialize per-message data */
326 	mci->mci_retryrcpt = false;
327 	mci->mci_tolist = NULL;
328 #if PIPELINING
329 	mci->mci_okrcpts = 0;
330 #endif /* PIPELINING */
331 
332 	if (mci->mci_rpool == NULL)
333 		mci->mci_rpool = sm_rpool_new_x(NULL);
334 
335 	if (mci->mci_macro.mac_rpool == NULL)
336 		mci->mci_macro.mac_rpool = mci->mci_rpool;
337 
338 	/*
339 	**  We don't need to load the persistent data if we have data
340 	**  already loaded in the cache.
341 	*/
342 
343 	if (mci->mci_host == NULL &&
344 	    (mci->mci_host = s->s_name) != NULL &&
345 	    !mci_load_persistent(mci))
346 	{
347 		if (tTd(42, 2))
348 			sm_dprintf("mci_get(%s %s): lock failed\n",
349 				host, m->m_name);
350 		mci->mci_exitstat = EX_TEMPFAIL;
351 		mci->mci_state = MCIS_CLOSED;
352 		mci->mci_statfile = NULL;
353 		return mci;
354 	}
355 
356 	if (tTd(42, 2))
357 	{
358 		sm_dprintf("mci_get(%s %s): mci_state=%d, _flags=%lx, _exitstat=%d, _errno=%d\n",
359 			host, m->m_name, mci->mci_state, mci->mci_flags,
360 			mci->mci_exitstat, mci->mci_errno);
361 	}
362 
363 	if (mci->mci_state == MCIS_OPEN)
364 	{
365 		/* poke the connection to see if it's still alive */
366 		(void) smtpprobe(mci);
367 
368 		/* reset the stored state in the event of a timeout */
369 		if (mci->mci_state != MCIS_OPEN)
370 		{
371 			mci->mci_errno = 0;
372 			mci->mci_exitstat = EX_OK;
373 			mci->mci_state = MCIS_CLOSED;
374 		}
375 		else
376 		{
377 			/* get peer host address */
378 			/* (this should really be in the mci struct) */
379 			SOCKADDR_LEN_T socklen = sizeof CurHostAddr;
380 
381 			(void) getpeername(sm_io_getinfo(mci->mci_in,
382 							 SM_IO_WHAT_FD, NULL),
383 				(struct sockaddr *) &CurHostAddr, &socklen);
384 		}
385 	}
386 	if (mci->mci_state == MCIS_CLOSED)
387 	{
388 		time_t now = curtime();
389 
390 		/* if this info is stale, ignore it */
391 		if (mci->mci_lastuse + MciInfoTimeout <= now)
392 		{
393 			mci->mci_lastuse = now;
394 			mci->mci_errno = 0;
395 			mci->mci_exitstat = EX_OK;
396 		}
397 	}
398 
399 	return mci;
400 }
401 
402 /*
403 **  MCI_CLOSE -- (forcefully) close files used for a connection.
404 **	Note: this is a last resort, usually smtpquit() or endmailer()
405 **		should be used to close a connection.
406 **
407 **	Parameters:
408 **		mci -- the connection to close.
409 **		where -- where has this been called?
410 **
411 **	Returns:
412 **		none.
413 */
414 
415 void
416 mci_close(mci, where)
417 	MCI *mci;
418 	char *where;
419 {
420 	bool dumped;
421 
422 	if (mci == NULL)
423 		return;
424 	dumped = false;
425 	if (mci->mci_out != NULL)
426 	{
427 		if (tTd(56, 1))
428 		{
429 			sm_dprintf("mci_close: mci_out!=NULL, where=%s\n",
430 				where);
431 			mci_dump(sm_debug_file(), mci, false);
432 			dumped = true;
433 		}
434 		(void) sm_io_close(mci->mci_out, SM_TIME_DEFAULT);
435 		mci->mci_out = NULL;
436 	}
437 	if (mci->mci_in != NULL)
438 	{
439 		if (tTd(56, 1))
440 		{
441 			sm_dprintf("mci_close: mci_in!=NULL, where=%s\n",
442 				where);
443 			if (!dumped)
444 				mci_dump(sm_debug_file(), mci, false);
445 		}
446 		(void) sm_io_close(mci->mci_in, SM_TIME_DEFAULT);
447 		mci->mci_in = NULL;
448 	}
449 	mci->mci_state = MCIS_CLOSED;
450 }
451 
452 /*
453 **  MCI_NEW -- allocate new MCI structure
454 **
455 **	Parameters:
456 **		rpool -- if non-NULL: allocate from that rpool.
457 **
458 **	Returns:
459 **		mci (new).
460 */
461 
462 MCI *
463 mci_new(rpool)
464 	SM_RPOOL_T *rpool;
465 {
466 	register MCI *mci;
467 
468 	if (rpool == NULL)
469 		mci = (MCI *) sm_malloc_x(sizeof *mci);
470 	else
471 		mci = (MCI *) sm_rpool_malloc_x(rpool, sizeof *mci);
472 	memset((char *) mci, '\0', sizeof *mci);
473 	mci->mci_rpool = sm_rpool_new_x(NULL);
474 	mci->mci_macro.mac_rpool = mci->mci_rpool;
475 	return mci;
476 }
477 /*
478 **  MCI_MATCH -- check connection cache for a particular host
479 **
480 **	Parameters:
481 **		host -- host to look for.
482 **		m -- mailer.
483 **
484 **	Returns:
485 **		true iff open connection exists.
486 */
487 
488 bool
489 mci_match(host, m)
490 	char *host;
491 	MAILER *m;
492 {
493 	register MCI *mci;
494 	register STAB *s;
495 
496 	if (m->m_mno < 0 || m->m_mno > MAXMAILERS)
497 		return false;
498 	s = stab(host, ST_MCI + m->m_mno, ST_FIND);
499 	if (s == NULL)
500 		return false;
501 
502 	mci = &s->s_mci;
503 	return mci->mci_state == MCIS_OPEN;
504 }
505 /*
506 **  MCI_SETSTAT -- set status codes in MCI structure.
507 **
508 **	Parameters:
509 **		mci -- the MCI structure to set.
510 **		xstat -- the exit status code.
511 **		dstat -- the DSN status code.
512 **		rstat -- the SMTP status code.
513 **
514 **	Returns:
515 **		none.
516 */
517 
518 void
519 mci_setstat(mci, xstat, dstat, rstat)
520 	MCI *mci;
521 	int xstat;
522 	char *dstat;
523 	char *rstat;
524 {
525 	/* protocol errors should never be interpreted as sticky */
526 	if (xstat != EX_NOTSTICKY && xstat != EX_PROTOCOL)
527 		mci->mci_exitstat = xstat;
528 
529 	SM_FREE_CLR(mci->mci_status);
530 	if (dstat != NULL)
531 		mci->mci_status = sm_strdup_x(dstat);
532 
533 	SM_FREE_CLR(mci->mci_rstatus);
534 	if (rstat != NULL)
535 		mci->mci_rstatus = sm_strdup_x(rstat);
536 }
537 /*
538 **  MCI_DUMP -- dump the contents of an MCI structure.
539 **
540 **	Parameters:
541 **		fp -- output file pointer
542 **		mci -- the MCI structure to dump.
543 **
544 **	Returns:
545 **		none.
546 **
547 **	Side Effects:
548 **		none.
549 */
550 
551 struct mcifbits
552 {
553 	int	mcif_bit;	/* flag bit */
554 	char	*mcif_name;	/* flag name */
555 };
556 static struct mcifbits	MciFlags[] =
557 {
558 	{ MCIF_VALID,		"VALID"		},
559 	{ MCIF_CACHED,		"CACHED"	},
560 	{ MCIF_ESMTP,		"ESMTP"		},
561 	{ MCIF_EXPN,		"EXPN"		},
562 	{ MCIF_SIZE,		"SIZE"		},
563 	{ MCIF_8BITMIME,	"8BITMIME"	},
564 	{ MCIF_7BIT,		"7BIT"		},
565 	{ MCIF_INHEADER,	"INHEADER"	},
566 	{ MCIF_CVT8TO7,		"CVT8TO7"	},
567 	{ MCIF_DSN,		"DSN"		},
568 	{ MCIF_8BITOK,		"8BITOK"	},
569 	{ MCIF_CVT7TO8,		"CVT7TO8"	},
570 	{ MCIF_INMIME,		"INMIME"	},
571 	{ MCIF_AUTH,		"AUTH"		},
572 	{ MCIF_AUTHACT,		"AUTHACT"	},
573 	{ MCIF_ENHSTAT,		"ENHSTAT"	},
574 	{ MCIF_PIPELINED,	"PIPELINED"	},
575 #if STARTTLS
576 	{ MCIF_TLS,		"TLS"		},
577 	{ MCIF_TLSACT,		"TLSACT"	},
578 #endif /* STARTTLS */
579 	{ MCIF_DLVR_BY,		"DLVR_BY"	},
580 	{ 0,			NULL		}
581 };
582 
583 void
584 mci_dump(fp, mci, logit)
585 	SM_FILE_T *fp;
586 	register MCI *mci;
587 	bool logit;
588 {
589 	register char *p;
590 	char *sep;
591 	char buf[4000];
592 
593 	sep = logit ? " " : "\n\t";
594 	p = buf;
595 	(void) sm_snprintf(p, SPACELEFT(buf, p), "MCI@%p: ", mci);
596 	p += strlen(p);
597 	if (mci == NULL)
598 	{
599 		(void) sm_snprintf(p, SPACELEFT(buf, p), "NULL");
600 		goto printit;
601 	}
602 	(void) sm_snprintf(p, SPACELEFT(buf, p), "flags=%lx", mci->mci_flags);
603 	p += strlen(p);
604 
605 	/*
606 	**  The following check is just for paranoia.  It protects the
607 	**  assignment in the if() clause. If there's not some minimum
608 	**  amount of space we can stop right now. The check will not
609 	**  trigger as long as sizeof(buf)=4000.
610 	*/
611 
612 	if (p >= buf + sizeof(buf) - 4)
613 		goto printit;
614 	if (mci->mci_flags != 0)
615 	{
616 		struct mcifbits *f;
617 
618 		*p++ = '<';	/* protected above */
619 		for (f = MciFlags; f->mcif_bit != 0; f++)
620 		{
621 			if (!bitset(f->mcif_bit, mci->mci_flags))
622 				continue;
623 			(void) sm_strlcpyn(p, SPACELEFT(buf, p), 2,
624 					   f->mcif_name, ",");
625 			p += strlen(p);
626 		}
627 		p[-1] = '>';
628 	}
629 
630 	/* Note: sm_snprintf() takes care of NULL arguments for %s */
631 	(void) sm_snprintf(p, SPACELEFT(buf, p),
632 		",%serrno=%d, herrno=%d, exitstat=%d, state=%d, pid=%d,%s",
633 		sep, mci->mci_errno, mci->mci_herrno,
634 		mci->mci_exitstat, mci->mci_state, (int) mci->mci_pid, sep);
635 	p += strlen(p);
636 	(void) sm_snprintf(p, SPACELEFT(buf, p),
637 		"maxsize=%ld, phase=%s, mailer=%s,%s",
638 		mci->mci_maxsize, mci->mci_phase,
639 		mci->mci_mailer == NULL ? "NULL" : mci->mci_mailer->m_name,
640 		sep);
641 	p += strlen(p);
642 	(void) sm_snprintf(p, SPACELEFT(buf, p),
643 		"status=%s, rstatus=%s,%s",
644 		mci->mci_status, mci->mci_rstatus, sep);
645 	p += strlen(p);
646 	(void) sm_snprintf(p, SPACELEFT(buf, p),
647 		"host=%s, lastuse=%s",
648 		mci->mci_host, ctime(&mci->mci_lastuse));
649 printit:
650 	if (logit)
651 		sm_syslog(LOG_DEBUG, CurEnv->e_id, "%.1000s", buf);
652 	else
653 		(void) sm_io_fprintf(fp, SM_TIME_DEFAULT, "%s\n", buf);
654 }
655 /*
656 **  MCI_DUMP_ALL -- print the entire MCI cache
657 **
658 **	Parameters:
659 **		fp -- output file pointer
660 **		logit -- if set, log the result instead of printing
661 **			to stdout.
662 **
663 **	Returns:
664 **		none.
665 */
666 
667 void
668 mci_dump_all(fp, logit)
669 	SM_FILE_T *fp;
670 	bool logit;
671 {
672 	register int i;
673 
674 	if (MciCache == NULL)
675 		return;
676 
677 	for (i = 0; i < MaxMciCache; i++)
678 		mci_dump(fp, MciCache[i], logit);
679 }
680 /*
681 **  MCI_LOCK_HOST -- Lock host while sending.
682 **
683 **	If we are contacting a host, we'll need to
684 **	update the status information in the host status
685 **	file, and if we want to do that, we ought to have
686 **	locked it. This has the (according to some)
687 **	desirable effect of serializing connectivity with
688 **	remote hosts -- i.e.: one connection to a given
689 **	host at a time.
690 **
691 **	Parameters:
692 **		mci -- containing the host we want to lock.
693 **
694 **	Returns:
695 **		EX_OK	    -- got the lock.
696 **		EX_TEMPFAIL -- didn't get the lock.
697 */
698 
699 int
700 mci_lock_host(mci)
701 	MCI *mci;
702 {
703 	if (mci == NULL)
704 	{
705 		if (tTd(56, 1))
706 			sm_dprintf("mci_lock_host: NULL mci\n");
707 		return EX_OK;
708 	}
709 
710 	if (!SingleThreadDelivery)
711 		return EX_OK;
712 
713 	return mci_lock_host_statfile(mci);
714 }
715 
716 static int
717 mci_lock_host_statfile(mci)
718 	MCI *mci;
719 {
720 	int save_errno = errno;
721 	int retVal = EX_OK;
722 	char fname[MAXPATHLEN];
723 
724 	if (HostStatDir == NULL || mci->mci_host == NULL)
725 		return EX_OK;
726 
727 	if (tTd(56, 2))
728 		sm_dprintf("mci_lock_host: attempting to lock %s\n",
729 			   mci->mci_host);
730 
731 	if (mci_generate_persistent_path(mci->mci_host, fname, sizeof fname,
732 					 true) < 0)
733 	{
734 		/* of course this should never happen */
735 		if (tTd(56, 2))
736 			sm_dprintf("mci_lock_host: Failed to generate host path for %s\n",
737 				   mci->mci_host);
738 
739 		retVal = EX_TEMPFAIL;
740 		goto cleanup;
741 	}
742 
743 	mci->mci_statfile = safefopen(fname, O_RDWR, FileMode,
744 				      SFF_NOLOCK|SFF_NOLINK|SFF_OPENASROOT|SFF_REGONLY|SFF_SAFEDIRPATH|SFF_CREAT);
745 
746 	if (mci->mci_statfile == NULL)
747 	{
748 		syserr("mci_lock_host: cannot create host lock file %s", fname);
749 		goto cleanup;
750 	}
751 
752 	if (!lockfile(sm_io_getinfo(mci->mci_statfile, SM_IO_WHAT_FD, NULL),
753 		      fname, "", LOCK_EX|LOCK_NB))
754 	{
755 		if (tTd(56, 2))
756 			sm_dprintf("mci_lock_host: couldn't get lock on %s\n",
757 				fname);
758 		(void) sm_io_close(mci->mci_statfile, SM_TIME_DEFAULT);
759 		mci->mci_statfile = NULL;
760 		retVal = EX_TEMPFAIL;
761 		goto cleanup;
762 	}
763 
764 	if (tTd(56, 12) && mci->mci_statfile != NULL)
765 		sm_dprintf("mci_lock_host: Sanity check -- lock is good\n");
766 
767 cleanup:
768 	errno = save_errno;
769 	return retVal;
770 }
771 /*
772 **  MCI_UNLOCK_HOST -- unlock host
773 **
774 **	Clean up the lock on a host, close the file, let
775 **	someone else use it.
776 **
777 **	Parameters:
778 **		mci -- us.
779 **
780 **	Returns:
781 **		nothing.
782 */
783 
784 void
785 mci_unlock_host(mci)
786 	MCI *mci;
787 {
788 	int save_errno = errno;
789 
790 	if (mci == NULL)
791 	{
792 		if (tTd(56, 1))
793 			sm_dprintf("mci_unlock_host: NULL mci\n");
794 		return;
795 	}
796 
797 	if (HostStatDir == NULL || mci->mci_host == NULL)
798 		return;
799 
800 	if (!SingleThreadDelivery && mci_lock_host_statfile(mci) == EX_TEMPFAIL)
801 	{
802 		if (tTd(56, 1))
803 			sm_dprintf("mci_unlock_host: stat file already locked\n");
804 	}
805 	else
806 	{
807 		if (tTd(56, 2))
808 			sm_dprintf("mci_unlock_host: store prior to unlock\n");
809 		mci_store_persistent(mci);
810 	}
811 
812 	if (mci->mci_statfile != NULL)
813 	{
814 		(void) sm_io_close(mci->mci_statfile, SM_TIME_DEFAULT);
815 		mci->mci_statfile = NULL;
816 	}
817 
818 	errno = save_errno;
819 }
820 /*
821 **  MCI_LOAD_PERSISTENT -- load persistent host info
822 **
823 **	Load information about host that is kept
824 **	in common for all running sendmails.
825 **
826 **	Parameters:
827 **		mci -- the host/connection to load persistent info for.
828 **
829 **	Returns:
830 **		true -- lock was successful
831 **		false -- lock failed
832 */
833 
834 static bool
835 mci_load_persistent(mci)
836 	MCI *mci;
837 {
838 	int save_errno = errno;
839 	bool locked = true;
840 	SM_FILE_T *fp;
841 	char fname[MAXPATHLEN];
842 
843 	if (mci == NULL)
844 	{
845 		if (tTd(56, 1))
846 			sm_dprintf("mci_load_persistent: NULL mci\n");
847 		return true;
848 	}
849 
850 	if (IgnoreHostStatus || HostStatDir == NULL || mci->mci_host == NULL)
851 		return true;
852 
853 	/* Already have the persistent information in memory */
854 	if (SingleThreadDelivery && mci->mci_statfile != NULL)
855 		return true;
856 
857 	if (tTd(56, 1))
858 		sm_dprintf("mci_load_persistent: Attempting to load persistent information for %s\n",
859 			   mci->mci_host);
860 
861 	if (mci_generate_persistent_path(mci->mci_host, fname, sizeof fname,
862 					 false) < 0)
863 	{
864 		/* Not much we can do if the file isn't there... */
865 		if (tTd(56, 1))
866 			sm_dprintf("mci_load_persistent: Couldn't generate host path\n");
867 		goto cleanup;
868 	}
869 
870 	fp = safefopen(fname, O_RDONLY, FileMode,
871 		       SFF_NOLOCK|SFF_NOLINK|SFF_OPENASROOT|SFF_REGONLY|SFF_SAFEDIRPATH);
872 	if (fp == NULL)
873 	{
874 		/* I can't think of any reason this should ever happen */
875 		if (tTd(56, 1))
876 			sm_dprintf("mci_load_persistent: open(%s): %s\n",
877 				fname, sm_errstring(errno));
878 		goto cleanup;
879 	}
880 
881 	FileName = fname;
882 	locked = lockfile(sm_io_getinfo(fp, SM_IO_WHAT_FD, NULL), fname, "",
883 			  LOCK_SH|LOCK_NB);
884 	if (locked)
885 	{
886 		(void) mci_read_persistent(fp, mci);
887 		(void) lockfile(sm_io_getinfo(fp, SM_IO_WHAT_FD, NULL), fname,
888 				"", LOCK_UN);
889 	}
890 	FileName = NULL;
891 	(void) sm_io_close(fp, SM_TIME_DEFAULT);
892 
893 cleanup:
894 	errno = save_errno;
895 	return locked;
896 }
897 /*
898 **  MCI_READ_PERSISTENT -- read persistent host status file
899 **
900 **	Parameters:
901 **		fp -- the file pointer to read.
902 **		mci -- the pointer to fill in.
903 **
904 **	Returns:
905 **		-1 -- if the file was corrupt.
906 **		0 -- otherwise.
907 **
908 **	Warning:
909 **		This code makes the assumption that this data
910 **		will be read in an atomic fashion, and that the data
911 **		was written in an atomic fashion.  Any other functioning
912 **		may lead to some form of insanity.  This should be
913 **		perfectly safe due to underlying stdio buffering.
914 */
915 
916 static int
917 mci_read_persistent(fp, mci)
918 	SM_FILE_T *fp;
919 	register MCI *mci;
920 {
921 	int ver;
922 	register char *p;
923 	int saveLineNumber = LineNumber;
924 	char buf[MAXLINE];
925 
926 	if (fp == NULL)
927 		syserr("mci_read_persistent: NULL fp");
928 	if (mci == NULL)
929 		syserr("mci_read_persistent: NULL mci");
930 	if (tTd(56, 93))
931 	{
932 		sm_dprintf("mci_read_persistent: fp=%lx, mci=",
933 			   (unsigned long) fp);
934 	}
935 
936 	SM_FREE_CLR(mci->mci_status);
937 	SM_FREE_CLR(mci->mci_rstatus);
938 
939 	sm_io_rewind(fp, SM_TIME_DEFAULT);
940 	ver = -1;
941 	LineNumber = 0;
942 	while (sm_io_fgets(fp, SM_TIME_DEFAULT, buf, sizeof buf) != NULL)
943 	{
944 		LineNumber++;
945 		p = strchr(buf, '\n');
946 		if (p != NULL)
947 			*p = '\0';
948 		switch (buf[0])
949 		{
950 		  case 'V':		/* version stamp */
951 			ver = atoi(&buf[1]);
952 			if (ver < 0 || ver > 0)
953 				syserr("Unknown host status version %d: %d max",
954 					ver, 0);
955 			break;
956 
957 		  case 'E':		/* UNIX error number */
958 			mci->mci_errno = atoi(&buf[1]);
959 			break;
960 
961 		  case 'H':		/* DNS error number */
962 			mci->mci_herrno = atoi(&buf[1]);
963 			break;
964 
965 		  case 'S':		/* UNIX exit status */
966 			mci->mci_exitstat = atoi(&buf[1]);
967 			break;
968 
969 		  case 'D':		/* DSN status */
970 			mci->mci_status = newstr(&buf[1]);
971 			break;
972 
973 		  case 'R':		/* SMTP status */
974 			mci->mci_rstatus = newstr(&buf[1]);
975 			break;
976 
977 		  case 'U':		/* last usage time */
978 			mci->mci_lastuse = atol(&buf[1]);
979 			break;
980 
981 		  case '.':		/* end of file */
982 			if (tTd(56, 93))
983 				mci_dump(sm_debug_file(), mci, false);
984 			return 0;
985 
986 		  default:
987 			sm_syslog(LOG_CRIT, NOQID,
988 				  "%s: line %d: Unknown host status line \"%s\"",
989 				  FileName == NULL ? mci->mci_host : FileName,
990 				  LineNumber, buf);
991 			LineNumber = saveLineNumber;
992 			return -1;
993 		}
994 	}
995 	LineNumber = saveLineNumber;
996 	if (tTd(56, 93))
997 		sm_dprintf("incomplete (missing dot for EOF)\n");
998 	if (ver < 0)
999 		return -1;
1000 	return 0;
1001 }
1002 /*
1003 **  MCI_STORE_PERSISTENT -- Store persistent MCI information
1004 **
1005 **	Store information about host that is kept
1006 **	in common for all running sendmails.
1007 **
1008 **	Parameters:
1009 **		mci -- the host/connection to store persistent info for.
1010 **
1011 **	Returns:
1012 **		none.
1013 */
1014 
1015 void
1016 mci_store_persistent(mci)
1017 	MCI *mci;
1018 {
1019 	int save_errno = errno;
1020 
1021 	if (mci == NULL)
1022 	{
1023 		if (tTd(56, 1))
1024 			sm_dprintf("mci_store_persistent: NULL mci\n");
1025 		return;
1026 	}
1027 
1028 	if (HostStatDir == NULL || mci->mci_host == NULL)
1029 		return;
1030 
1031 	if (tTd(56, 1))
1032 		sm_dprintf("mci_store_persistent: Storing information for %s\n",
1033 			   mci->mci_host);
1034 
1035 	if (mci->mci_statfile == NULL)
1036 	{
1037 		if (tTd(56, 1))
1038 			sm_dprintf("mci_store_persistent: no statfile\n");
1039 		return;
1040 	}
1041 
1042 	sm_io_rewind(mci->mci_statfile, SM_TIME_DEFAULT);
1043 #if !NOFTRUNCATE
1044 	(void) ftruncate(sm_io_getinfo(mci->mci_statfile, SM_IO_WHAT_FD, NULL),
1045 			 (off_t) 0);
1046 #endif /* !NOFTRUNCATE */
1047 
1048 	(void) sm_io_fprintf(mci->mci_statfile, SM_TIME_DEFAULT, "V0\n");
1049 	(void) sm_io_fprintf(mci->mci_statfile, SM_TIME_DEFAULT, "E%d\n",
1050 			     mci->mci_errno);
1051 	(void) sm_io_fprintf(mci->mci_statfile, SM_TIME_DEFAULT, "H%d\n",
1052 			     mci->mci_herrno);
1053 	(void) sm_io_fprintf(mci->mci_statfile, SM_TIME_DEFAULT, "S%d\n",
1054 			     mci->mci_exitstat);
1055 	if (mci->mci_status != NULL)
1056 		(void) sm_io_fprintf(mci->mci_statfile, SM_TIME_DEFAULT,
1057 				     "D%.80s\n",
1058 				     denlstring(mci->mci_status, true, false));
1059 	if (mci->mci_rstatus != NULL)
1060 		(void) sm_io_fprintf(mci->mci_statfile, SM_TIME_DEFAULT,
1061 				     "R%.80s\n",
1062 				     denlstring(mci->mci_rstatus, true, false));
1063 	(void) sm_io_fprintf(mci->mci_statfile, SM_TIME_DEFAULT, "U%ld\n",
1064 			     (long)(mci->mci_lastuse));
1065 	(void) sm_io_fprintf(mci->mci_statfile, SM_TIME_DEFAULT, ".\n");
1066 
1067 	(void) sm_io_flush(mci->mci_statfile, SM_TIME_DEFAULT);
1068 
1069 	errno = save_errno;
1070 	return;
1071 }
1072 /*
1073 **  MCI_TRAVERSE_PERSISTENT -- walk persistent status tree
1074 **
1075 **	Recursively find all the mci host files in `pathname'.  Default to
1076 **		main host status directory if no path is provided.
1077 **	Call (*action)(pathname, host) for each file found.
1078 **
1079 **	Note: all information is collected in a list before it is processed.
1080 **	This may not be the best way to do it, but it seems safest, since
1081 **	the file system would be touched while we are attempting to traverse
1082 **	the directory tree otherwise (during purges).
1083 **
1084 **	Parameters:
1085 **		action -- function to call on each node.  If returns < 0,
1086 **			return immediately.
1087 **		pathname -- root of tree.  If null, use main host status
1088 **			directory.
1089 **
1090 **	Returns:
1091 **		< 0 -- if any action routine returns a negative value, that
1092 **			value is returned.
1093 **		0 -- if we successfully went to completion.
1094 **		> 0 -- return status from action()
1095 */
1096 
1097 int
1098 mci_traverse_persistent(action, pathname)
1099 	int (*action)__P((char *, char *));
1100 	char *pathname;
1101 {
1102 	struct stat statbuf;
1103 	DIR *d;
1104 	int ret;
1105 
1106 	if (pathname == NULL)
1107 		pathname = HostStatDir;
1108 	if (pathname == NULL)
1109 		return -1;
1110 
1111 	if (tTd(56, 1))
1112 		sm_dprintf("mci_traverse: pathname is %s\n", pathname);
1113 
1114 	ret = stat(pathname, &statbuf);
1115 	if (ret < 0)
1116 	{
1117 		if (tTd(56, 2))
1118 			sm_dprintf("mci_traverse: Failed to stat %s: %s\n",
1119 				pathname, sm_errstring(errno));
1120 		return ret;
1121 	}
1122 	if (S_ISDIR(statbuf.st_mode))
1123 	{
1124 		bool leftone, removedone;
1125 		size_t len;
1126 		char *newptr;
1127 		struct dirent *e;
1128 		char newpath[MAXPATHLEN];
1129 #if MAXPATHLEN <= MAXNAMLEN - 3
1130  ERROR "MAXPATHLEN <= MAXNAMLEN - 3"
1131 #endif /* MAXPATHLEN  <= MAXNAMLEN - 3 */
1132 
1133 		if ((d = opendir(pathname)) == NULL)
1134 		{
1135 			if (tTd(56, 2))
1136 				sm_dprintf("mci_traverse: opendir %s: %s\n",
1137 					pathname, sm_errstring(errno));
1138 			return -1;
1139 		}
1140 		len = sizeof(newpath) - MAXNAMLEN - 3;
1141 		if (sm_strlcpy(newpath, pathname, len) >= len)
1142 		{
1143 			if (tTd(56, 2))
1144 				sm_dprintf("mci_traverse: path \"%s\" too long",
1145 					pathname);
1146 			return -1;
1147 		}
1148 		newptr = newpath + strlen(newpath);
1149 		*newptr++ = '/';
1150 
1151 		/*
1152 		**  repeat until no file has been removed
1153 		**  this may become ugly when several files "expire"
1154 		**  during these loops, but it's better than doing
1155 		**  a rewinddir() inside the inner loop
1156 		*/
1157 
1158 		do
1159 		{
1160 			leftone = removedone = false;
1161 			while ((e = readdir(d)) != NULL)
1162 			{
1163 				if (e->d_name[0] == '.')
1164 					continue;
1165 
1166 				(void) sm_strlcpy(newptr, e->d_name,
1167 					       sizeof newpath -
1168 					       (newptr - newpath));
1169 
1170 				if (StopRequest)
1171 					stop_sendmail();
1172 				ret = mci_traverse_persistent(action, newpath);
1173 				if (ret < 0)
1174 					break;
1175 				if (ret == 1)
1176 					leftone = true;
1177 				if (!removedone && ret == 0 &&
1178 				    action == mci_purge_persistent)
1179 					removedone = true;
1180 			}
1181 			if (ret < 0)
1182 				break;
1183 
1184 			/*
1185 			**  The following appears to be
1186 			**  necessary during purges, since
1187 			**  we modify the directory structure
1188 			*/
1189 
1190 			if (removedone)
1191 				rewinddir(d);
1192 			if (tTd(56, 40))
1193 				sm_dprintf("mci_traverse: path %s: ret %d removed %d left %d\n",
1194 					pathname, ret, removedone, leftone);
1195 		} while (removedone);
1196 
1197 		/* purge (or whatever) the directory proper */
1198 		if (!leftone)
1199 		{
1200 			*--newptr = '\0';
1201 			ret = (*action)(newpath, NULL);
1202 		}
1203 		(void) closedir(d);
1204 	}
1205 	else if (S_ISREG(statbuf.st_mode))
1206 	{
1207 		char *end = pathname + strlen(pathname) - 1;
1208 		char *start;
1209 		char *scan;
1210 		char host[MAXHOSTNAMELEN];
1211 		char *hostptr = host;
1212 
1213 		/*
1214 		**  Reconstruct the host name from the path to the
1215 		**  persistent information.
1216 		*/
1217 
1218 		do
1219 		{
1220 			if (hostptr != host)
1221 				*(hostptr++) = '.';
1222 			start = end;
1223 			while (start > pathname && *(start - 1) != '/')
1224 				start--;
1225 
1226 			if (*end == '.')
1227 				end--;
1228 
1229 			for (scan = start; scan <= end; scan++)
1230 				*(hostptr++) = *scan;
1231 
1232 			end = start - 2;
1233 		} while (end > pathname && *end == '.');
1234 
1235 		*hostptr = '\0';
1236 
1237 		/*
1238 		**  Do something with the file containing the persistent
1239 		**  information.
1240 		*/
1241 
1242 		ret = (*action)(pathname, host);
1243 	}
1244 
1245 	return ret;
1246 }
1247 /*
1248 **  MCI_PRINT_PERSISTENT -- print persistent info
1249 **
1250 **	Dump the persistent information in the file 'pathname'
1251 **
1252 **	Parameters:
1253 **		pathname -- the pathname to the status file.
1254 **		hostname -- the corresponding host name.
1255 **
1256 **	Returns:
1257 **		0
1258 */
1259 
1260 int
1261 mci_print_persistent(pathname, hostname)
1262 	char *pathname;
1263 	char *hostname;
1264 {
1265 	static bool initflag = false;
1266 	SM_FILE_T *fp;
1267 	int width = Verbose ? 78 : 25;
1268 	bool locked;
1269 	MCI mcib;
1270 
1271 	/* skip directories */
1272 	if (hostname == NULL)
1273 		return 0;
1274 
1275 	if (StopRequest)
1276 		stop_sendmail();
1277 
1278 	if (!initflag)
1279 	{
1280 		initflag = true;
1281 		(void) sm_io_fprintf(smioout, SM_TIME_DEFAULT,
1282 				     " -------------- Hostname --------------- How long ago ---------Results---------\n");
1283 	}
1284 
1285 	fp = safefopen(pathname, O_RDONLY, FileMode,
1286 		       SFF_NOLOCK|SFF_NOLINK|SFF_OPENASROOT|SFF_REGONLY|SFF_SAFEDIRPATH);
1287 
1288 	if (fp == NULL)
1289 	{
1290 		if (tTd(56, 1))
1291 			sm_dprintf("mci_print_persistent: cannot open %s: %s\n",
1292 				pathname, sm_errstring(errno));
1293 		return 0;
1294 	}
1295 
1296 	FileName = pathname;
1297 	memset(&mcib, '\0', sizeof mcib);
1298 	if (mci_read_persistent(fp, &mcib) < 0)
1299 	{
1300 		syserr("%s: could not read status file", pathname);
1301 		(void) sm_io_close(fp, SM_TIME_DEFAULT);
1302 		FileName = NULL;
1303 		return 0;
1304 	}
1305 
1306 	locked = !lockfile(sm_io_getinfo(fp, SM_IO_WHAT_FD, NULL), pathname,
1307 			   "", LOCK_SH|LOCK_NB);
1308 	(void) sm_io_close(fp, SM_TIME_DEFAULT);
1309 	FileName = NULL;
1310 
1311 	(void) sm_io_fprintf(smioout, SM_TIME_DEFAULT, "%c%-39s %12s ",
1312 			     locked ? '*' : ' ', hostname,
1313 			     pintvl(curtime() - mcib.mci_lastuse, true));
1314 	if (mcib.mci_rstatus != NULL)
1315 		(void) sm_io_fprintf(smioout, SM_TIME_DEFAULT, "%.*s\n", width,
1316 				     mcib.mci_rstatus);
1317 	else if (mcib.mci_exitstat == EX_TEMPFAIL && mcib.mci_errno != 0)
1318 		(void) sm_io_fprintf(smioout, SM_TIME_DEFAULT,
1319 				     "Deferred: %.*s\n", width - 10,
1320 				     sm_errstring(mcib.mci_errno));
1321 	else if (mcib.mci_exitstat != 0)
1322 	{
1323 		char *exmsg = sm_sysexmsg(mcib.mci_exitstat);
1324 
1325 		if (exmsg == NULL)
1326 		{
1327 			char buf[80];
1328 
1329 			(void) sm_snprintf(buf, sizeof buf,
1330 				"Unknown mailer error %d",
1331 				mcib.mci_exitstat);
1332 			(void) sm_io_fprintf(smioout, SM_TIME_DEFAULT, "%.*s\n",
1333 					     width, buf);
1334 		}
1335 		else
1336 			(void) sm_io_fprintf(smioout, SM_TIME_DEFAULT, "%.*s\n",
1337 					     width, &exmsg[5]);
1338 	}
1339 	else if (mcib.mci_errno == 0)
1340 		(void) sm_io_fprintf(smioout, SM_TIME_DEFAULT, "OK\n");
1341 	else
1342 		(void) sm_io_fprintf(smioout, SM_TIME_DEFAULT, "OK: %.*s\n",
1343 				     width - 4, sm_errstring(mcib.mci_errno));
1344 
1345 	return 0;
1346 }
1347 /*
1348 **  MCI_PURGE_PERSISTENT -- Remove a persistence status file.
1349 **
1350 **	Parameters:
1351 **		pathname -- path to the status file.
1352 **		hostname -- name of host corresponding to that file.
1353 **			NULL if this is a directory (domain).
1354 **
1355 **	Returns:
1356 **		0 -- ok
1357 **		1 -- file not deleted (too young, incorrect format)
1358 **		< 0 -- some error occurred
1359 */
1360 
1361 int
1362 mci_purge_persistent(pathname, hostname)
1363 	char *pathname;
1364 	char *hostname;
1365 {
1366 	struct stat statbuf;
1367 	char *end = pathname + strlen(pathname) - 1;
1368 	int ret;
1369 
1370 	if (tTd(56, 1))
1371 		sm_dprintf("mci_purge_persistent: purging %s\n", pathname);
1372 
1373 	ret = stat(pathname, &statbuf);
1374 	if (ret < 0)
1375 	{
1376 		if (tTd(56, 2))
1377 			sm_dprintf("mci_purge_persistent: Failed to stat %s: %s\n",
1378 				pathname, sm_errstring(errno));
1379 		return ret;
1380 	}
1381 	if (curtime() - statbuf.st_mtime <= MciInfoTimeout)
1382 		return 1;
1383 	if (hostname != NULL)
1384 	{
1385 		/* remove the file */
1386 		ret = unlink(pathname);
1387 		if (ret < 0)
1388 		{
1389 			if (LogLevel > 8)
1390 				sm_syslog(LOG_ERR, NOQID,
1391 					  "mci_purge_persistent: failed to unlink %s: %s",
1392 					  pathname, sm_errstring(errno));
1393 			if (tTd(56, 2))
1394 				sm_dprintf("mci_purge_persistent: failed to unlink %s: %s\n",
1395 					pathname, sm_errstring(errno));
1396 			return ret;
1397 		}
1398 	}
1399 	else
1400 	{
1401 		/* remove the directory */
1402 		if (*end != '.')
1403 			return 1;
1404 
1405 		if (tTd(56, 1))
1406 			sm_dprintf("mci_purge_persistent: dpurge %s\n", pathname);
1407 
1408 		ret = rmdir(pathname);
1409 		if (ret < 0)
1410 		{
1411 			if (tTd(56, 2))
1412 				sm_dprintf("mci_purge_persistent: rmdir %s: %s\n",
1413 					pathname, sm_errstring(errno));
1414 			return ret;
1415 		}
1416 	}
1417 
1418 	return 0;
1419 }
1420 /*
1421 **  MCI_GENERATE_PERSISTENT_PATH -- generate path from hostname
1422 **
1423 **	Given `host', convert from a.b.c to $HostStatDir/c./b./a,
1424 **	putting the result into `path'.  if `createflag' is set, intervening
1425 **	directories will be created as needed.
1426 **
1427 **	Parameters:
1428 **		host -- host name to convert from.
1429 **		path -- place to store result.
1430 **		pathlen -- length of path buffer.
1431 **		createflag -- if set, create intervening directories as
1432 **			needed.
1433 **
1434 **	Returns:
1435 **		0 -- success
1436 **		-1 -- failure
1437 */
1438 
1439 static int
1440 mci_generate_persistent_path(host, path, pathlen, createflag)
1441 	const char *host;
1442 	char *path;
1443 	int pathlen;
1444 	bool createflag;
1445 {
1446 	char *elem, *p, *x, ch;
1447 	int ret = 0;
1448 	int len;
1449 	char t_host[MAXHOSTNAMELEN];
1450 #if NETINET6
1451 	struct in6_addr in6_addr;
1452 #endif /* NETINET6 */
1453 
1454 	/*
1455 	**  Rationality check the arguments.
1456 	*/
1457 
1458 	if (host == NULL)
1459 	{
1460 		syserr("mci_generate_persistent_path: null host");
1461 		return -1;
1462 	}
1463 	if (path == NULL)
1464 	{
1465 		syserr("mci_generate_persistent_path: null path");
1466 		return -1;
1467 	}
1468 
1469 	if (tTd(56, 80))
1470 		sm_dprintf("mci_generate_persistent_path(%s): ", host);
1471 
1472 	if (*host == '\0' || *host == '.')
1473 		return -1;
1474 
1475 	/* make certain this is not a bracketed host number */
1476 	if (strlen(host) > sizeof t_host - 1)
1477 		return -1;
1478 	if (host[0] == '[')
1479 		(void) sm_strlcpy(t_host, host + 1, sizeof t_host);
1480 	else
1481 		(void) sm_strlcpy(t_host, host, sizeof t_host);
1482 
1483 	/*
1484 	**  Delete any trailing dots from the hostname.
1485 	**  Leave 'elem' pointing at the \0.
1486 	*/
1487 
1488 	elem = t_host + strlen(t_host);
1489 	while (elem > t_host &&
1490 	       (elem[-1] == '.' || (host[0] == '[' && elem[-1] == ']')))
1491 		*--elem = '\0';
1492 
1493 	/* check for bogus bracketed address */
1494 	if (host[0] == '[')
1495 	{
1496 		bool good = false;
1497 # if NETINET6
1498 		if (anynet_pton(AF_INET6, t_host, &in6_addr) == 1)
1499 			good = true;
1500 # endif /* NETINET6 */
1501 # if NETINET
1502 		if (inet_addr(t_host) != INADDR_NONE)
1503 			good = true;
1504 # endif /* NETINET */
1505 		if (!good)
1506 			return -1;
1507 	}
1508 
1509 	/* check for what will be the final length of the path */
1510 	len = strlen(HostStatDir) + 2;
1511 	for (p = (char *) t_host; *p != '\0'; p++)
1512 	{
1513 		if (*p == '.')
1514 			len++;
1515 		len++;
1516 		if (p[0] == '.' && p[1] == '.')
1517 			return -1;
1518 	}
1519 	if (len > pathlen || len < 1)
1520 		return -1;
1521 	(void) sm_strlcpy(path, HostStatDir, pathlen);
1522 	p = path + strlen(path);
1523 	while (elem > t_host)
1524 	{
1525 		if (!path_is_dir(path, createflag))
1526 		{
1527 			ret = -1;
1528 			break;
1529 		}
1530 		elem--;
1531 		while (elem >= t_host && *elem != '.')
1532 			elem--;
1533 		*p++ = '/';
1534 		x = elem + 1;
1535 		while ((ch = *x++) != '\0' && ch != '.')
1536 		{
1537 			if (isascii(ch) && isupper(ch))
1538 				ch = tolower(ch);
1539 			if (ch == '/')
1540 				ch = ':';	/* / -> : */
1541 			*p++ = ch;
1542 		}
1543 		if (elem >= t_host)
1544 			*p++ = '.';
1545 		*p = '\0';
1546 	}
1547 	if (tTd(56, 80))
1548 	{
1549 		if (ret < 0)
1550 			sm_dprintf("FAILURE %d\n", ret);
1551 		else
1552 			sm_dprintf("SUCCESS %s\n", path);
1553 	}
1554 	return ret;
1555 }
1556