xref: /openbsd-src/sbin/resolvd/resolvd.c (revision 8475ebac2505d97cb3bdff76dc6b72401d329e63)
1 /*	$OpenBSD: resolvd.c,v 1.32 2022/12/09 18:22:35 tb Exp $	*/
2 /*
3  * Copyright (c) 2021 Florian Obser <florian@openbsd.org>
4  * Copyright (c) 2021 Theo de Raadt <deraadt@openbsd.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <sys/types.h>
20 #include <sys/event.h>
21 #include <sys/socket.h>
22 #include <sys/stat.h>
23 #include <sys/syslog.h>
24 #include <sys/time.h>
25 #include <sys/un.h>
26 #include <netdb.h>
27 
28 #include <arpa/inet.h>
29 #include <netinet/in.h>
30 #include <net/if.h>
31 #include <net/route.h>
32 
33 #include <err.h>
34 #include <errno.h>
35 #include <fcntl.h>
36 #include <event.h>
37 #include <signal.h>
38 #include <stddef.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <unistd.h>
43 
44 #define	ROUTE_SOCKET_BUF_SIZE	16384
45 #define	ASR_MAXNS		10
46 #define	_PATH_LOCKFILE		"/dev/resolvd.lock"
47 #define	_PATH_UNWIND_SOCKET	"/dev/unwind.sock"
48 #define	_PATH_RESCONF		"/etc/resolv.conf"
49 #define	_PATH_RESCONF_NEW	"/etc/resolv.conf.new"
50 
51 #ifndef nitems
52 #define	nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
53 #endif
54 
55 __dead void	usage(void);
56 
57 struct rdns_proposal {
58 	uint32_t	 if_index;
59 	int		 af;
60 	int		 prio;
61 	char		 ip[INET6_ADDRSTRLEN];
62 };
63 
64 void		route_receive(int);
65 void		handle_route_message(struct rt_msghdr *, struct sockaddr **);
66 void		get_rtaddrs(int, struct sockaddr *, struct sockaddr **);
67 void		solicit_dns_proposals(int);
68 void		regen_resolvconf(const char *reason);
69 int		cmp(const void *, const void *);
70 int		findslot(struct rdns_proposal *);
71 void		zeroslot(struct rdns_proposal *);
72 
73 struct rdns_proposal	 learned[ASR_MAXNS];
74 int			 resolvfd = -1;
75 int			 newkevent = 1;
76 
77 #ifndef SMALL
78 int			 open_unwind_ctl(void);
79 int			 check_unwind = 1, unwind_running = 0;
80 
81 struct loggers {
82 	__dead void (*err)(int, const char *, ...)
83 	    __attribute__((__format__ (printf, 2, 3)));
84 	__dead void (*errx)(int, const char *, ...)
85 	    __attribute__((__format__ (printf, 2, 3)));
86 	void (*warn)(const char *, ...)
87 	    __attribute__((__format__ (printf, 1, 2)));
88 	void (*warnx)(const char *, ...)
89 	    __attribute__((__format__ (printf, 1, 2)));
90 	void (*info)(const char *, ...)
91 	    __attribute__((__format__ (printf, 1, 2)));
92 	void (*debug)(const char *, ...)
93 	    __attribute__((__format__ (printf, 1, 2)));
94 };
95 
96 void		warnx_verbose(const char *, ...)
97 		    __attribute__((__format__ (printf, 1, 2)));
98 
99 const struct loggers conslogger = {
100 	err,
101 	errx,
102 	warn,
103 	warnx,
104 	warnx_verbose, /* info */
105 	warnx_verbose /* debug */
106 };
107 
108 __dead void	syslog_err(int, const char *, ...)
109 		    __attribute__((__format__ (printf, 2, 3)));
110 __dead void	syslog_errx(int, const char *, ...)
111 		    __attribute__((__format__ (printf, 2, 3)));
112 void		syslog_warn(const char *, ...)
113 		    __attribute__((__format__ (printf, 1, 2)));
114 void		syslog_warnx(const char *, ...)
115 		    __attribute__((__format__ (printf, 1, 2)));
116 void		syslog_info(const char *, ...)
117 		    __attribute__((__format__ (printf, 1, 2)));
118 void		syslog_debug(const char *, ...)
119 		    __attribute__((__format__ (printf, 1, 2)));
120 void		syslog_vstrerror(int, int, const char *, va_list)
121 		    __attribute__((__format__ (printf, 3, 0)));
122 
123 int verbose = 0;
124 
125 const struct loggers syslogger = {
126 	syslog_err,
127 	syslog_errx,
128 	syslog_warn,
129 	syslog_warnx,
130 	syslog_info,
131 	syslog_debug
132 };
133 
134 const struct loggers *logger = &conslogger;
135 
136 #define lerr(_e, _f...) logger->err((_e), _f)
137 #define lerrx(_e, _f...) logger->errx((_e), _f)
138 #define lwarn(_f...) logger->warn(_f)
139 #define lwarnx(_f...) logger->warnx(_f)
140 #define linfo(_f...) logger->info(_f)
141 #define ldebug(_f...) logger->debug(_f)
142 #else
143 #define lerr(x...) do {} while(0)
144 #define lerrx(x...) do {} while(0)
145 #define lwarn(x...) do {} while(0)
146 #define lwarnx(x...) do {} while(0)
147 #define linfo(x...) do {} while(0)
148 #define ldebug(x...) do {} while(0)
149 #endif /* SMALL */
150 
151 enum {
152 	KQ_ROUTE,
153 	KQ_RESOLVE_CONF,
154 #ifndef SMALL
155 	KQ_UNWIND,
156 #endif
157 	KQ_TOTAL
158 };
159 
160 int
main(int argc,char * argv[])161 main(int argc, char *argv[])
162 {
163 	struct timespec		 one = {1, 0};
164 	int			 kq, ch, debug = 0, routesock;
165 	int			 rtfilter, nready, lockfd;
166 	struct kevent		 kev[KQ_TOTAL];
167 #ifndef SMALL
168 	int			 unwindsock = -1;
169 #endif
170 
171 	while ((ch = getopt(argc, argv, "dv")) != -1) {
172 		switch (ch) {
173 		case 'd':
174 			debug = 1;
175 			break;
176 		case 'v':
177 #ifndef SMALL
178 			verbose++;
179 #endif
180 			break;
181 		default:
182 			usage();
183 		}
184 	}
185 
186 	argc -= optind;
187 	argv += optind;
188 	if (argc > 0)
189 		usage();
190 
191 	/* Check for root privileges. */
192 	if (geteuid())
193 		errx(1, "need root privileges");
194 
195 	lockfd = open(_PATH_LOCKFILE, O_CREAT|O_RDWR|O_EXLOCK|O_NONBLOCK, 0600);
196 	if (lockfd == -1) {
197 		if (errno == EAGAIN)
198 			errx(1, "already running");
199 		err(1, "%s", _PATH_LOCKFILE);
200 	}
201 
202 	if (!debug)
203 		daemon(0, 0);
204 
205 #ifndef SMALL
206 	if (!debug) {
207 		openlog("resolvd", LOG_PID|LOG_NDELAY, LOG_DAEMON);
208 		logger = &syslogger;
209 	}
210 #endif
211 
212 	signal(SIGHUP, SIG_IGN);
213 
214 	if ((routesock = socket(AF_ROUTE, SOCK_RAW, 0)) == -1)
215 		lerr(1, "route socket");
216 
217 	rtfilter = ROUTE_FILTER(RTM_PROPOSAL) | ROUTE_FILTER(RTM_IFANNOUNCE);
218 	if (setsockopt(routesock, AF_ROUTE, ROUTE_MSGFILTER, &rtfilter,
219 	    sizeof(rtfilter)) == -1)
220 		lerr(1, "setsockopt(ROUTE_MSGFILTER)");
221 
222 	solicit_dns_proposals(routesock);
223 
224 	if (unveil(_PATH_RESCONF, "rwc") == -1)
225 		lerr(1, "unveil " _PATH_RESCONF);
226 	if (unveil(_PATH_RESCONF_NEW, "rwc") == -1)
227 		lerr(1, "unveil " _PATH_RESCONF_NEW);
228 #ifndef SMALL
229 	if (unveil(_PATH_UNWIND_SOCKET, "w") == -1)
230 		lerr(1, "unveil " _PATH_UNWIND_SOCKET);
231 #endif
232 
233 	if (pledge("stdio unix rpath wpath cpath", NULL) == -1)
234 		lerr(1, "pledge");
235 
236 	if ((kq = kqueue()) == -1)
237 		lerr(1, "kqueue");
238 
239 	for(;;) {
240 		int	i;
241 
242 #ifndef SMALL
243 		if (!unwind_running && check_unwind) {
244 			check_unwind = 0;
245 			unwindsock = open_unwind_ctl();
246 			unwind_running = unwindsock != -1;
247 			if (unwind_running)
248 				regen_resolvconf("new unwind");
249 		}
250 #endif
251 
252 		if (newkevent) {
253 			int kevi = 0;
254 
255 			if (routesock != -1)
256 				EV_SET(&kev[kevi++], routesock, EVFILT_READ,
257 				    EV_ADD, 0, 0,
258 				    (void *)KQ_ROUTE);
259 			if (resolvfd != -1)
260 				EV_SET(&kev[kevi++], resolvfd, EVFILT_VNODE,
261 				    EV_ADD | EV_CLEAR,
262 				    NOTE_DELETE | NOTE_RENAME | NOTE_TRUNCATE | NOTE_WRITE, 0,
263 				    (void *)KQ_RESOLVE_CONF);
264 
265 #ifndef SMALL
266 			if (unwind_running) {
267 				EV_SET(&kev[kevi++], unwindsock, EVFILT_READ,
268 				    EV_ADD, 0, 0,
269 				    (void *)KQ_UNWIND);
270 			}
271 #endif /* SMALL */
272 
273 			if (kevent(kq, kev, kevi, NULL, 0, NULL) == -1)
274 				lerr(1, "kevent");
275 			newkevent = 0;
276 		}
277 
278 		nready = kevent(kq, NULL, 0, kev, KQ_TOTAL, NULL);
279 		if (nready == -1) {
280 			if (errno == EINTR)
281 				continue;
282 			lerr(1, "kevent");
283 		}
284 
285 		if (nready == 0)
286 			continue;
287 
288 		for (i = 0; i < nready; i++) {
289 			unsigned short fflags = kev[i].fflags;
290 
291 			switch ((int)(long)kev[i].udata) {
292 			case KQ_ROUTE:
293 				route_receive(routesock);
294 				break;
295 
296 			case KQ_RESOLVE_CONF:
297 				if (fflags & (NOTE_DELETE | NOTE_RENAME)) {
298 					close(resolvfd);
299 					resolvfd = -1;
300 					regen_resolvconf("file delete/rename");
301 				}
302 				if (fflags & (NOTE_TRUNCATE | NOTE_WRITE)) {
303 					/* some editors truncate and write */
304 					if (fflags & NOTE_TRUNCATE)
305 						nanosleep(&one, NULL);
306 					regen_resolvconf("file trunc/write");
307 				}
308 				break;
309 
310 #ifndef SMALL
311 			case KQ_UNWIND: {
312 				uint8_t buf[1024];
313 				ssize_t	n;
314 
315 				n = read(unwindsock, buf, sizeof(buf));
316 				if (n == -1) {
317 					if (errno == EAGAIN || errno == EINTR)
318 						continue;
319 				}
320 				if (n == 0 || n == -1) {
321 					if (n == -1)
322 						check_unwind = 1;
323 					newkevent = 1;
324 					close(unwindsock);
325 					unwindsock = -1;
326 					unwind_running = 0;
327 					regen_resolvconf("unwind closed");
328 				} else
329 					lwarnx("read %ld from unwind ctl", n);
330 				break;
331 			}
332 #endif
333 
334 			default:
335 				lwarnx("unknown kqueue event on %lu",
336 				    kev[i].ident);
337 			}
338 		}
339 	}
340 	return 0;
341 }
342 
343 __dead void
usage(void)344 usage(void)
345 {
346 	fprintf(stderr, "usage: resolvd [-dv]\n");
347 	exit(1);
348 }
349 
350 void
route_receive(int fd)351 route_receive(int fd)
352 {
353 	uint8_t			 rsock_buf[ROUTE_SOCKET_BUF_SIZE];
354 	struct sockaddr		*sa, *rti_info[RTAX_MAX];
355 	struct rt_msghdr	*rtm;
356 	ssize_t			 n;
357 
358 	rtm = (struct rt_msghdr *) rsock_buf;
359 	if ((n = read(fd, rsock_buf, sizeof(rsock_buf))) == -1) {
360 		if (errno == EAGAIN || errno == EINTR)
361 			return;
362 		lwarn("%s: read error", __func__);
363 		return;
364 	}
365 
366 	if (n == 0)
367 		lerr(1, "routing socket closed");
368 
369 	if (n < (ssize_t)sizeof(rtm->rtm_msglen) || n < rtm->rtm_msglen) {
370 		lwarnx("partial rtm of %zd in buffer", n);
371 		return;
372 	}
373 
374 	if (rtm->rtm_version != RTM_VERSION)
375 		return;
376 
377 	if (rtm->rtm_pid == getpid())
378 		return;
379 
380 	sa = (struct sockaddr *)(rsock_buf + rtm->rtm_hdrlen);
381 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
382 	handle_route_message(rtm, rti_info);
383 }
384 
385 void
zeroslot(struct rdns_proposal * tab)386 zeroslot(struct rdns_proposal *tab)
387 {
388 	tab->prio = 0;
389 	tab->af = 0;
390 	tab->if_index = 0;
391 	tab->ip[0] = '\0';
392 }
393 
394 int
findslot(struct rdns_proposal * tab)395 findslot(struct rdns_proposal *tab)
396 {
397 	int i;
398 
399 	for (i = 0; i < ASR_MAXNS; i++)
400 		if (tab[i].prio == 0)
401 			return i;
402 
403 	/* New proposals might be important, so replace the last slot */
404 	i = ASR_MAXNS - 1;
405 	zeroslot(&tab[i]);
406 	return i;
407 }
408 
409 void
handle_route_message(struct rt_msghdr * rtm,struct sockaddr ** rti_info)410 handle_route_message(struct rt_msghdr *rtm, struct sockaddr **rti_info)
411 {
412 	struct rdns_proposal		 learning[nitems(learned)];
413 	struct sockaddr_rtdns		*rtdns;
414 	struct if_announcemsghdr	*ifan;
415 	size_t				 addrsz;
416 	int				 rdns_count, af, i;
417 	char				*src;
418 
419 	memcpy(learning, learned, sizeof learned);
420 
421 	switch (rtm->rtm_type) {
422 	case RTM_IFANNOUNCE:
423 		ifan = (struct if_announcemsghdr *)rtm;
424 		if (ifan->ifan_what == IFAN_ARRIVAL)
425 			return;
426 		/* Delete proposals learned from departing interfaces */
427 		for (i = 0; i < ASR_MAXNS; i++)
428 			if (learning[i].if_index == ifan->ifan_index)
429 				zeroslot(&learning[i]);
430 		break;
431 	case RTM_PROPOSAL:
432 		if (rtm->rtm_priority == RTP_PROPOSAL_SOLICIT) {
433 #ifndef SMALL
434 			check_unwind = 1;
435 #endif /* SMALL */
436 			return;
437 		}
438 
439 		if (!(rtm->rtm_addrs & RTA_DNS))
440 			return;
441 
442 		rtdns = (struct sockaddr_rtdns*)rti_info[RTAX_DNS];
443 		src = rtdns->sr_dns;
444 		af = rtdns->sr_family;
445 
446 		switch (af) {
447 		case AF_INET:
448 			addrsz = sizeof(struct in_addr);
449 			break;
450 		case AF_INET6:
451 			addrsz = sizeof(struct in6_addr);
452 			break;
453 		default:
454 			lwarnx("ignoring invalid RTM_PROPOSAL");
455 			return;
456 		}
457 
458 		if ((rtdns->sr_len - 2) % addrsz != 0) {
459 			lwarnx("ignoring invalid RTM_PROPOSAL");
460 			return;
461 		}
462 		rdns_count = (rtdns->sr_len -
463 		    offsetof(struct sockaddr_rtdns, sr_dns)) / addrsz;
464 
465 		/* New proposal from interface means previous proposals expire */
466 		for (i = 0; i < ASR_MAXNS; i++)
467 			if (learning[i].af == af &&
468 			    learning[i].if_index == rtm->rtm_index)
469 				zeroslot(&learning[i]);
470 
471 		/* Add the new proposals */
472 		for (i = 0; i < rdns_count; i++) {
473 			struct sockaddr_storage ss;
474 			struct sockaddr_in *sin = (struct sockaddr_in *)&ss;
475 			struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&ss;
476 			int new, err;
477 
478 			memset(&ss, 0, sizeof(ss));
479 			ss.ss_family = af;
480 			new = findslot(learning);
481 			switch (af) {
482 			case AF_INET:
483 				memcpy(&sin->sin_addr, src, addrsz);
484 				ss.ss_len = sizeof(*sin);
485 				break;
486 			case AF_INET6:
487 				memcpy(&sin6->sin6_addr, src, addrsz);
488 				if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
489 					sin6->sin6_scope_id = rtm->rtm_index;
490 				ss.ss_len = sizeof(*sin6);
491 				break;
492 			}
493 			src += addrsz;
494 
495 			if ((err = getnameinfo((struct sockaddr *)&ss, ss.ss_len,
496 			    learning[new].ip, sizeof(learning[new].ip),
497 			    NULL, 0, NI_NUMERICHOST)) == 0) {
498 				learning[new].prio = rtm->rtm_priority;
499 				learning[new].if_index = rtm->rtm_index;
500 				learning[new].af = af;
501 			} else
502 				lwarnx("getnameinfo: %s", gai_strerror(err));
503 		}
504 		break;
505 	default:
506 		return;
507 	}
508 
509 	/* Sort proposals, based upon priority */
510 	if (mergesort(learning, ASR_MAXNS, sizeof(learning[0]), cmp) == -1) {
511 		lwarn("mergesort");
512 		return;
513 	}
514 
515 	/* Eliminate duplicate IPs per interface */
516 	for (i = 0; i < ASR_MAXNS - 1; i++) {
517 		int j;
518 
519 		if (learning[i].prio == 0)
520 			continue;
521 
522 		for (j = i + 1; j < ASR_MAXNS; j++) {
523 			if (learning[i].if_index == learning[j].if_index &&
524 			    strcmp(learning[i].ip, learning[j].ip) == 0) {
525 				zeroslot(&learning[j]);
526 			}
527 		}
528 	}
529 
530 	/* If proposal result is different, rebuild the file */
531 	if (memcmp(learned, learning, sizeof(learned)) != 0) {
532 		memcpy(learned, learning, sizeof(learned));
533 		regen_resolvconf("route proposals");
534 	}
535 }
536 
537 #define ROUNDUP(a) \
538 	((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
539 
540 void
get_rtaddrs(int addrs,struct sockaddr * sa,struct sockaddr ** rti_info)541 get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
542 {
543 	int	i;
544 
545 	for (i = 0; i < RTAX_MAX; i++) {
546 		if (addrs & (1 << i)) {
547 			rti_info[i] = sa;
548 			sa = (struct sockaddr *)((char *)(sa) +
549 			    ROUNDUP(sa->sa_len));
550 		} else
551 			rti_info[i] = NULL;
552 	}
553 }
554 
555 void
solicit_dns_proposals(int routesock)556 solicit_dns_proposals(int routesock)
557 {
558 	struct rt_msghdr	 rtm;
559 	struct iovec		 iov[1];
560 	int			 iovcnt = 0;
561 
562 	memset(&rtm, 0, sizeof(rtm));
563 
564 	rtm.rtm_version = RTM_VERSION;
565 	rtm.rtm_type = RTM_PROPOSAL;
566 	rtm.rtm_msglen = sizeof(rtm);
567 	rtm.rtm_tableid = 0;
568 	rtm.rtm_index = 0;
569 	rtm.rtm_seq = arc4random();
570 	rtm.rtm_priority = RTP_PROPOSAL_SOLICIT;
571 
572 	iov[iovcnt].iov_base = &rtm;
573 	iov[iovcnt++].iov_len = sizeof(rtm);
574 
575 	if (writev(routesock, iov, iovcnt) == -1)
576 		lwarn("failed to send solicitation");
577 }
578 
579 void
regen_resolvconf(const char * why)580 regen_resolvconf(const char *why)
581 {
582 	struct iovec	 iov[UIO_MAXIOV];
583 	int		 i, fd, len, iovcnt = 0;
584 
585 	linfo("rebuilding: %s", why);
586 
587 	if ((fd = open(_PATH_RESCONF_NEW, O_CREAT|O_TRUNC|O_RDWR, 0644)) == -1) {
588 		lwarn(_PATH_RESCONF_NEW);
589 		return;
590 	}
591 
592 	memset(iov, 0, sizeof(iov));
593 
594 #ifndef SMALL
595 	if (unwind_running) {
596 		len = asprintf((char **)&iov[iovcnt].iov_base,
597 		    "nameserver 127.0.0.1 # resolvd: unwind\n");
598 		if (len < 0) {
599 			lwarn("asprintf");
600 			goto err;
601 		}
602 		iov[iovcnt++].iov_len = len;
603 	}
604 
605 #endif /* SMALL */
606 	for (i = 0; i < ASR_MAXNS; i++) {
607 		if (learned[i].prio != 0) {
608 			char ifnambuf[IF_NAMESIZE], *ifnam;
609 
610 			ifnam = if_indextoname(learned[i].if_index,
611 			    ifnambuf);
612 			len = asprintf((char **)&iov[iovcnt].iov_base,
613 			    "%snameserver %s # resolvd: %s\n",
614 #ifndef SMALL
615 			    unwind_running ? "#" : "",
616 #else
617 			    "",
618 #endif
619 			    learned[i].ip,
620 			    ifnam ? ifnam : "");
621 			if (len < 0) {
622 				lwarn("asprintf");
623 				goto err;
624 			}
625 			iov[iovcnt++].iov_len = len;
626 		}
627 	}
628 
629 	/* Replay user-managed lines from old resolv.conf file */
630 	if (resolvfd == -1)
631 		resolvfd = open(_PATH_RESCONF, O_RDWR);
632 	if (resolvfd != -1) {
633 		char *line = NULL;
634 		size_t linesize = 0;
635 		ssize_t linelen;
636 		FILE *fp;
637 		int fd2;
638 
639 		if ((fd2 = dup(resolvfd)) == -1)
640 			goto err;
641 		lseek(fd2, 0, SEEK_SET);
642 		fp = fdopen(fd2, "r");
643 		if (fp == NULL) {
644 			close(fd2);
645 			goto err;
646 		}
647 		while ((linelen = getline(&line, &linesize, fp)) != -1) {
648 			char *end = strchr(line, '\n');
649 			if (end)
650 				*end = '\0';
651 			if (strstr(line, "# resolvd: "))
652 				continue;
653 			len = asprintf((char **)&iov[iovcnt].iov_base, "%s\n",
654 			    line);
655 			if (len < 0) {
656 				lwarn("asprintf");
657 				free(line);
658 				fclose(fp);
659 				goto err;
660 			}
661 			iov[iovcnt++].iov_len = len;
662 			if (iovcnt >= UIO_MAXIOV) {
663 				lwarnx("too many user-managed lines");
664 				free(line);
665 				fclose(fp);
666 				goto err;
667 			}
668 		}
669 		free(line);
670 		fclose(fp);
671 	}
672 
673 	if (iovcnt > 0) {
674 		if (writev(fd, iov, iovcnt) == -1) {
675 			lwarn("writev");
676 			goto err;
677 		}
678 	}
679 
680 	if (fsync(fd) == -1) {
681 		lwarn("fsync");
682 		goto err;
683 	}
684 	if (rename(_PATH_RESCONF_NEW, _PATH_RESCONF) == -1)
685 		goto err;
686 
687 	if (resolvfd == -1) {
688 		close(fd);
689 		resolvfd = open(_PATH_RESCONF, O_RDWR);
690 	} else {
691 		dup2(fd, resolvfd);
692 		close(fd);
693 	}
694 
695 	newkevent = 1;
696 	goto out;
697 
698  err:
699 	if (fd != -1)
700 		close(fd);
701 	unlink(_PATH_RESCONF_NEW);
702  out:
703 	for (i = 0; i < iovcnt; i++)
704 		free(iov[i].iov_base);
705 
706 }
707 
708 int
cmp(const void * a,const void * b)709 cmp(const void *a, const void *b)
710 {
711 	const struct rdns_proposal	*rpa = a, *rpb = b;
712 
713 	return (rpa->prio < rpb->prio) ? -1 : (rpa->prio > rpb->prio);
714 }
715 
716 #ifndef SMALL
717 int
open_unwind_ctl(void)718 open_unwind_ctl(void)
719 {
720 	static struct sockaddr_un	 sun;
721 	int				 s;
722 
723 	if (sun.sun_family == 0) {
724 		sun.sun_family = AF_UNIX;
725 		strlcpy(sun.sun_path, _PATH_UNWIND_SOCKET, sizeof(sun.sun_path));
726 	}
727 
728 	if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) != -1) {
729 		if (connect(s, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
730 			close(s);
731 			s = -1;
732 		}
733 	}
734 	newkevent = 1;
735 	return s;
736 }
737 
738 void
syslog_vstrerror(int e,int priority,const char * fmt,va_list ap)739 syslog_vstrerror(int e, int priority, const char *fmt, va_list ap)
740 {
741 	char *s;
742 
743 	if (vasprintf(&s, fmt, ap) == -1) {
744 		syslog(LOG_EMERG, "unable to alloc in syslog_vstrerror");
745 		exit(1);
746 	}
747 	syslog(priority, "%s: %s", s, strerror(e));
748 	free(s);
749 }
750 
751 __dead void
syslog_err(int ecode,const char * fmt,...)752 syslog_err(int ecode, const char *fmt, ...)
753 {
754 	va_list ap;
755 
756 	va_start(ap, fmt);
757 	syslog_vstrerror(errno, LOG_CRIT, fmt, ap);
758 	va_end(ap);
759 	exit(ecode);
760 }
761 
762 __dead void
syslog_errx(int ecode,const char * fmt,...)763 syslog_errx(int ecode, const char *fmt, ...)
764 {
765 	va_list ap;
766 
767 	va_start(ap, fmt);
768 	vsyslog(LOG_CRIT, fmt, ap);
769 	va_end(ap);
770 	exit(ecode);
771 }
772 
773 void
syslog_warn(const char * fmt,...)774 syslog_warn(const char *fmt, ...)
775 {
776 	va_list ap;
777 
778 	va_start(ap, fmt);
779 	syslog_vstrerror(errno, LOG_ERR, fmt, ap);
780 	va_end(ap);
781 }
782 
783 void
syslog_warnx(const char * fmt,...)784 syslog_warnx(const char *fmt, ...)
785 {
786 	va_list ap;
787 
788 	va_start(ap, fmt);
789 	vsyslog(LOG_ERR, fmt, ap);
790 	va_end(ap);
791 }
792 
793 void
syslog_info(const char * fmt,...)794 syslog_info(const char *fmt, ...)
795 {
796 	va_list ap;
797 
798 	va_start(ap, fmt);
799 	vsyslog(LOG_INFO, fmt, ap);
800 	va_end(ap);
801 }
802 
803 void
syslog_debug(const char * fmt,...)804 syslog_debug(const char *fmt, ...)
805 {
806 	va_list ap;
807 
808 	va_start(ap, fmt);
809 	vsyslog(LOG_DEBUG, fmt, ap);
810 	va_end(ap);
811 }
812 
813 void
warnx_verbose(const char * fmt,...)814 warnx_verbose(const char *fmt, ...)
815 {
816 	va_list ap;
817 
818 	va_start(ap, fmt);
819 	if (verbose)
820 		vwarnx(fmt, ap);
821 	va_end(ap);
822 }
823 
824 #endif /* SMALL */
825