xref: /freebsd/usr.sbin/ypbind/ypbind.c (revision 5ebc7e6281887681c3a348a5a4c902e262ccd656)
1 /*
2  * Copyright (c) 1992/3 Theo de Raadt <deraadt@fsa.ca>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. The name of the author may not be used to endorse or promote
14  *    products derived from this software without specific prior written
15  *    permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
18  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #ifndef LINT
31 static char rcsid[] = "$Id: ypbind.c,v 1.14 1995/05/29 16:39:52 wpaul Exp $";
32 #endif
33 
34 #include <sys/param.h>
35 #include <sys/types.h>
36 #include <sys/wait.h>
37 #include <sys/ioctl.h>
38 #include <sys/signal.h>
39 #include <sys/socket.h>
40 #include <sys/file.h>
41 #include <sys/fcntl.h>
42 #include <sys/stat.h>
43 #include <sys/uio.h>
44 #include <syslog.h>
45 #include <stdio.h>
46 #include <errno.h>
47 #include <ctype.h>
48 #include <dirent.h>
49 #include <netdb.h>
50 #include <string.h>
51 #include <rpc/rpc.h>
52 #include <rpc/xdr.h>
53 #include <net/if.h>
54 #include <netinet/in.h>
55 #include <arpa/inet.h>
56 #include <rpc/pmap_clnt.h>
57 #include <rpc/pmap_prot.h>
58 #include <rpc/pmap_rmt.h>
59 #include <unistd.h>
60 #include <stdlib.h>
61 #include <rpcsvc/yp_prot.h>
62 #include <rpcsvc/ypclnt.h>
63 
64 #ifndef BINDINGDIR
65 #define BINDINGDIR "/var/yp/binding"
66 #endif
67 
68 #ifndef YPBINDLOCK
69 #define YPBINDLOCK "/var/run/ypbind.lock"
70 #endif
71 
72 struct _dom_binding {
73 	struct _dom_binding *dom_pnext;
74 	char dom_domain[YPMAXDOMAIN + 1];
75 	struct sockaddr_in dom_server_addr;
76 	long int dom_vers;
77 	int dom_lockfd;
78 	int dom_alive;
79 	int dom_broadcast_pid;
80 	int dom_pipe_fds[2];
81 	int dom_default;
82 };
83 
84 #define READFD ypdb->dom_pipe_fds[0]
85 #define WRITEFD ypdb->dom_pipe_fds[1]
86 #define BROADFD broad_domain->dom_pipe_fds[1]
87 
88 extern bool_t xdr_domainname(), xdr_ypbind_resp();
89 extern bool_t xdr_ypreq_key(), xdr_ypresp_val();
90 extern bool_t xdr_ypbind_setdom();
91 
92 void	checkwork __P((void));
93 void	*ypbindproc_null_2 __P((SVCXPRT *, void *, CLIENT *));
94 void	*ypbindproc_setdom_2 __P((SVCXPRT *, struct ypbind_setdom *, CLIENT *));
95 void	rpc_received __P((char *, struct sockaddr_in *, int ));
96 void	broadcast __P((struct _dom_binding *));
97 int	ping __P((struct _dom_binding *));
98 int	tell_parent __P((char *, struct sockaddr_in *));
99 void	handle_children __P(( struct _dom_binding * ));
100 void	reaper __P((int));
101 void	terminate __P((int));
102 
103 char *domainname;
104 struct _dom_binding *ypbindlist;
105 static struct _dom_binding *broad_domain;
106 
107 #define YPSET_NO	0
108 #define YPSET_LOCAL	1
109 #define YPSET_ALL	2
110 int ypsetmode = YPSET_NO;
111 int ypsecuremode = 0;
112 
113 /* No more than MAX_CHILDREN child broadcasters at a time. */
114 #ifndef MAX_CHILDREN
115 #define MAX_CHILDREN 5
116 #endif
117 /* No more than MAX_DOMAINS simultaneous domains */
118 #ifndef MAX_DOMAINS
119 #define MAX_DOMAINS 200
120 #endif
121 /* RPC timeout value */
122 #ifndef FAIL_THRESHOLD
123 #define FAIL_THRESHOLD 10
124 #endif
125 
126 int children = 0;
127 int domains = 0;
128 int yplockfd;
129 fd_set fdsr;
130 
131 SVCXPRT *udptransp, *tcptransp;
132 
133 void *
134 ypbindproc_null_2(transp, argp, clnt)
135 SVCXPRT *transp;
136 void *argp;
137 CLIENT *clnt;
138 {
139 	static char res;
140 
141 	bzero((char *)&res, sizeof(res));
142 	return (void *)&res;
143 }
144 
145 struct ypbind_resp *
146 ypbindproc_domain_2(transp, argp, clnt)
147 SVCXPRT *transp;
148 char *argp;
149 CLIENT *clnt;
150 {
151 	static struct ypbind_resp res;
152 	struct _dom_binding *ypdb;
153 	char path[MAXPATHLEN];
154 
155 	bzero((char *)&res, sizeof res);
156 	res.ypbind_status = YPBIND_FAIL_VAL;
157 	res.ypbind_respbody.ypbind_error = YPBIND_ERR_NOSERV;
158 
159 	for(ypdb=ypbindlist; ypdb; ypdb=ypdb->dom_pnext) {
160 		if( strcmp(ypdb->dom_domain, argp) == 0)
161 			break;
162 		}
163 
164 	if(ypdb==NULL) {
165 		if (domains >= MAX_DOMAINS) {
166 			syslog(LOG_WARNING, "domain limit (%d) exceeded",
167 							MAX_DOMAINS);
168 			res.ypbind_respbody.ypbind_error = YPBIND_ERR_RESC;
169 			return &res;
170 		}
171 		ypdb = (struct _dom_binding *)malloc(sizeof *ypdb);
172 		if (ypdb == NULL) {
173 			syslog(LOG_WARNING, "malloc: %s", strerror(errno));
174 			res.ypbind_respbody.ypbind_error = YPBIND_ERR_RESC;
175 			return &res;
176 		}
177 		bzero((char *)ypdb, sizeof *ypdb);
178 		strncpy(ypdb->dom_domain, argp, sizeof ypdb->dom_domain);
179 		ypdb->dom_vers = YPVERS;
180 		ypdb->dom_alive = 0;
181 		ypdb->dom_default = 0;
182 		ypdb->dom_lockfd = -1;
183 		sprintf(path, "%s/%s.%ld", BINDINGDIR,
184 					ypdb->dom_domain, ypdb->dom_vers);
185 		unlink(path);
186 		ypdb->dom_pnext = ypbindlist;
187 		ypbindlist = ypdb;
188 		domains++;
189 	}
190 
191 	if (ping(ypdb)) {
192 		return &res;
193 	}
194 
195 	res.ypbind_status = YPBIND_SUCC_VAL;
196 	res.ypbind_respbody.ypbind_error = 0; /* Success */
197 	res.ypbind_respbody.ypbind_bindinfo.ypbind_binding_addr.s_addr =
198 		ypdb->dom_server_addr.sin_addr.s_addr;
199 	res.ypbind_respbody.ypbind_bindinfo.ypbind_binding_port =
200 		ypdb->dom_server_addr.sin_port;
201 	/*printf("domain %s at %s/%d\n", ypdb->dom_domain,
202 		inet_ntoa(ypdb->dom_server_addr.sin_addr),
203 		ntohs(ypdb->dom_server_addr.sin_port));*/
204 	return &res;
205 }
206 
207 void *
208 ypbindproc_setdom_2(transp, argp, clnt)
209 SVCXPRT *transp;
210 struct ypbind_setdom *argp;
211 CLIENT *clnt;
212 {
213 	struct sockaddr_in *fromsin, bindsin;
214 
215 	fromsin = svc_getcaller(transp);
216 
217 	switch(ypsetmode) {
218 	case YPSET_LOCAL:
219 		if( fromsin->sin_addr.s_addr != htonl(INADDR_LOOPBACK)) {
220 			svcerr_noprog(transp);
221 			return;
222 		}
223 		break;
224 	case YPSET_ALL:
225 		break;
226 	case YPSET_NO:
227 	default:
228 		svcerr_noprog(transp);
229 		return;
230 	}
231 
232 	if(ntohs(fromsin->sin_port) >= IPPORT_RESERVED) {
233 		svcerr_noprog(transp);
234 		return;
235 	}
236 
237 	if(argp->ypsetdom_vers != YPVERS) {
238 		svcerr_noprog(transp);
239 		return;
240 	}
241 
242 	bzero((char *)&bindsin, sizeof bindsin);
243 	bindsin.sin_family = AF_INET;
244 	bindsin.sin_addr.s_addr = argp->ypsetdom_addr.s_addr;
245 	bindsin.sin_port = argp->ypsetdom_port;
246 	rpc_received(argp->ypsetdom_domain, &bindsin, 1);
247 
248 	return;
249 }
250 
251 static void
252 ypbindprog_2(rqstp, transp)
253 struct svc_req *rqstp;
254 register SVCXPRT *transp;
255 {
256 	union {
257 		char ypbindproc_domain_2_arg[MAXHOSTNAMELEN];
258 		struct ypbind_setdom ypbindproc_setdom_2_arg;
259 	} argument;
260 	struct authunix_parms *creds;
261 	char *result;
262 	bool_t (*xdr_argument)(), (*xdr_result)();
263 	char *(*local)();
264 
265 	switch (rqstp->rq_proc) {
266 	case YPBINDPROC_NULL:
267 		xdr_argument = xdr_void;
268 		xdr_result = xdr_void;
269 		local = (char *(*)()) ypbindproc_null_2;
270 		break;
271 
272 	case YPBINDPROC_DOMAIN:
273 		xdr_argument = xdr_domainname;
274 		xdr_result = xdr_ypbind_resp;
275 		local = (char *(*)()) ypbindproc_domain_2;
276 		break;
277 
278 	case YPBINDPROC_SETDOM:
279 		switch(rqstp->rq_cred.oa_flavor) {
280 		case AUTH_UNIX:
281 			creds = (struct authunix_parms *)rqstp->rq_clntcred;
282 			if( creds->aup_uid != 0) {
283 				svcerr_auth(transp, AUTH_BADCRED);
284 				return;
285 			}
286 			break;
287 		default:
288 			svcerr_auth(transp, AUTH_TOOWEAK);
289 			return;
290 		}
291 
292 		xdr_argument = xdr_ypbind_setdom;
293 		xdr_result = xdr_void;
294 		local = (char *(*)()) ypbindproc_setdom_2;
295 		break;
296 
297 	default:
298 		svcerr_noproc(transp);
299 		return;
300 	}
301 	bzero((char *)&argument, sizeof(argument));
302 	if (!svc_getargs(transp, xdr_argument, &argument)) {
303 		svcerr_decode(transp);
304 		return;
305 	}
306 	result = (*local)(transp, &argument, rqstp);
307 	if (result != NULL && !svc_sendreply(transp, xdr_result, result)) {
308 		svcerr_systemerr(transp);
309 	}
310 	return;
311 }
312 
313 /* Jack the reaper */
314 void reaper(sig)
315 int sig;
316 {
317 	int st;
318 
319 	wait3(&st, WNOHANG, NULL);
320 }
321 
322 void terminate(sig)
323 int sig;
324 {
325 	struct _dom_binding *ypdb;
326 	char path[MAXPATHLEN];
327 
328 	for(ypdb=ypbindlist; ypdb; ypdb=ypdb->dom_pnext) {
329 		close(ypdb->dom_lockfd);
330 		if (ypdb->dom_broadcast_pid)
331 			kill(ypdb->dom_broadcast_pid, SIGINT);
332 		sprintf(path, "%s/%s.%ld", BINDINGDIR,
333 			ypdb->dom_domain, ypdb->dom_vers);
334 		unlink(path);
335 	}
336 	close(yplockfd);
337 	unlink(YPBINDLOCK);
338 	pmap_unset(YPBINDPROG, YPBINDVERS);
339 	exit(0);
340 }
341 
342 void
343 main(argc, argv)
344 int argc;
345 char **argv;
346 {
347 	char path[MAXPATHLEN];
348 	struct timeval tv;
349 	int i;
350 	DIR *dird;
351 	struct dirent *dirp;
352 	struct _dom_binding *ypdb;
353 
354 	/* Check that another ypbind isn't already running. */
355 	if ((yplockfd = (open(YPBINDLOCK, O_RDONLY|O_CREAT, 0444))) == -1) {
356 		perror(YPBINDLOCK);
357 		exit(1);
358 	}
359 
360 	if(flock(yplockfd, LOCK_EX|LOCK_NB) == -1 && errno == EWOULDBLOCK) {
361 		fprintf (stderr, "Another ypbind is already running. Aborting.\n");
362 		exit(1);
363 	}
364 
365 	yp_get_default_domain(&domainname);
366 	if( domainname[0] == '\0') {
367 		fprintf(stderr, "domainname not set. Aborting.\n");
368 		exit(1);
369 	}
370 
371 	for(i=1; i<argc; i++) {
372 		if( strcmp("-ypset", argv[i]) == 0)
373 			ypsetmode = YPSET_ALL;
374 		else if (strcmp("-ypsetme", argv[i]) == 0)
375 		        ypsetmode = YPSET_LOCAL;
376 		else if (strcmp("-s", argv[i]) == 0)
377 		        ypsecuremode++;
378 	}
379 
380 	/* blow away everything in BINDINGDIR (if it exists) */
381 
382 	if ((dird = opendir(BINDINGDIR)) != NULL) {
383 		char path[MAXPATHLEN];
384 		while ((dirp = readdir(dird)) != NULL)
385 			if (strcmp(dirp->d_name, ".") &&
386 			    strcmp(dirp->d_name, "..")) {
387 				sprintf(path,"%s/%s",BINDINGDIR,dirp->d_name);
388 				unlink(path);
389 			}
390 		closedir(dird);
391 	}
392 
393 #ifdef DAEMON
394 	if (daemon(0,0)) {
395 		perror("fork");
396 		exit(1);
397 	}
398 #endif
399 
400 	pmap_unset(YPBINDPROG, YPBINDVERS);
401 
402 	udptransp = svcudp_create(RPC_ANYSOCK);
403 	if (udptransp == NULL) {
404 		fprintf(stderr, "cannot create udp service.\n");
405 		exit(1);
406 	}
407 	if (!svc_register(udptransp, YPBINDPROG, YPBINDVERS, ypbindprog_2,
408 	    IPPROTO_UDP)) {
409 		fprintf(stderr, "unable to register (YPBINDPROG, YPBINDVERS, udp).\n");
410 		exit(1);
411 	}
412 
413 	tcptransp = svctcp_create(RPC_ANYSOCK, 0, 0);
414 	if (tcptransp == NULL) {
415 		fprintf(stderr, "cannot create tcp service.\n");
416 		exit(1);
417 	}
418 
419 	if (!svc_register(tcptransp, YPBINDPROG, YPBINDVERS, ypbindprog_2,
420 	    IPPROTO_TCP)) {
421 		fprintf(stderr, "unable to register (YPBINDPROG, YPBINDVERS, tcp).\n");
422 		exit(1);
423 	}
424 
425 	/* build initial domain binding, make it "unsuccessful" */
426 	ypbindlist = (struct _dom_binding *)malloc(sizeof *ypbindlist);
427 	if (ypbindlist == NULL) {
428 		perror("malloc");
429 		exit(1);
430 	}
431 	bzero((char *)ypbindlist, sizeof *ypbindlist);
432 	strncpy(ypbindlist->dom_domain, domainname, sizeof ypbindlist->dom_domain);
433 	ypbindlist->dom_vers = YPVERS;
434 	ypbindlist->dom_alive = 0;
435 	ypbindlist->dom_lockfd = -1;
436 	ypbindlist->dom_default = 1;
437 	domains++;
438 
439 	signal(SIGCHLD, reaper);
440 	signal(SIGTERM, terminate);
441 
442 	openlog(argv[0], LOG_PID, LOG_DAEMON);
443 
444 	/* Kick off the default domain */
445 	broadcast(ypbindlist);
446 
447 	while(1) {
448 		fdsr = svc_fdset;
449 
450 		tv.tv_sec = 60;
451 		tv.tv_usec = 0;
452 
453 		switch(select(_rpc_dtablesize(), &fdsr, NULL, NULL, &tv)) {
454 		case 0:
455 			checkwork();
456 			break;
457 		case -1:
458 			if (errno != EINTR)
459 				syslog(LOG_WARNING, "select: %s", strerror(errno));
460 			break;
461 		default:
462 			for(ypdb=ypbindlist; ypdb; ypdb=ypdb->dom_pnext) {
463 				if (READFD > 0 && FD_ISSET(READFD, &fdsr)) {
464 					handle_children(ypdb);
465 					children--;
466 					if (children == (MAX_CHILDREN - 1))
467 						checkwork();
468 				}
469 			}
470 			svc_getreqset(&fdsr);
471 			break;
472 		}
473 	}
474 }
475 
476 void
477 checkwork()
478 {
479 	struct _dom_binding *ypdb;
480 
481 	for(ypdb=ypbindlist; ypdb; ypdb=ypdb->dom_pnext)
482 		ping(ypdb);
483 }
484 
485 /* The clnt_broadcast() callback mechanism sucks. */
486 
487 /*
488  * Receive results from broadcaster. Don't worry about passing
489  * bogus info to rpc_received() -- it can handle it. Note that we
490  * must be sure to invalidate the dom_pipe_fds descriptors here:
491  * since descriptors can be re-used, we have to make sure we
492  * don't mistake one of the RPC descriptors for one of the pipes.
493  * What's weird is that forgetting to invalidate the pipe descriptors
494  * doesn't always result in an error (otherwise I would have caught
495  * the mistake much sooner), even though logically it should.
496  */
497 void handle_children(ypdb)
498 struct _dom_binding *ypdb;
499 {
500 	char buf[YPMAXDOMAIN + 1];
501 	struct sockaddr_in addr;
502 
503 	if (read(READFD, &buf, sizeof(buf)) < 0)
504 		syslog(LOG_WARNING, "could not read from child: %s", strerror(errno));
505 	if (read(READFD, &addr, sizeof(struct sockaddr_in)) < 0)
506 		syslog(LOG_WARNING, "could not read from child: %s", strerror(errno));
507 
508 	close(READFD);
509 	FD_CLR(READFD, &fdsr);
510 	FD_CLR(READFD, &svc_fdset);
511 	READFD = WRITEFD = -1;
512 	rpc_received((char *)&buf, &addr, 0);
513 }
514 
515 /*
516  * Send our dying words back to our parent before we perish.
517  */
518 int
519 tell_parent(dom, addr)
520 char *dom;
521 struct sockaddr_in *addr;
522 {
523 	char buf[YPMAXDOMAIN + 1];
524 	struct timeval timeout;
525 	fd_set fds;
526 
527 	timeout.tv_sec = 5;
528 	timeout.tv_usec = 0;
529 
530 	sprintf(buf, "%s", broad_domain->dom_domain);
531 	if (write(BROADFD, &buf, sizeof(buf)) < 0)
532 		return(1);
533 
534 	/*
535 	 * Stay in sync with parent: wait for it to read our first
536 	 * message before sending the second.
537 	 */
538 
539 	FD_ZERO(&fds);
540 	FD_SET(BROADFD, &fds);
541 	if (select(FD_SETSIZE, NULL, &fds, NULL, &timeout) == -1)
542 		return(1);
543 	if (FD_ISSET(BROADFD, &fds)) {
544 		if (write(BROADFD, addr, sizeof(struct sockaddr_in)) < 0)
545 			return(1);
546 	} else {
547 		return(1);
548 	}
549 
550 	close(BROADFD);
551 	return (0);
552 }
553 
554 bool_t broadcast_result(out, addr)
555 bool_t *out;
556 struct sockaddr_in *addr;
557 {
558 	if (tell_parent(broad_domain->dom_domain, addr))
559 		syslog(LOG_WARNING, "lost connection to parent");
560 	return TRUE;
561 }
562 
563 /*
564  * The right way to send RPC broadcasts.
565  * Use the clnt_broadcast() RPC service. Unfortunately, clnt_broadcast()
566  * blocks while waiting for replies, so we have to fork off seperate
567  * broadcaster processes that do the waiting and then transmit their
568  * results back to the parent for processing. We also have to remember
569  * to save the name of the domain we're trying to bind in a global
570  * variable since clnt_broadcast() provides no way to pass things to
571  * the 'eachresult' callback function.
572  */
573 void
574 broadcast(ypdb)
575 struct _dom_binding *ypdb;
576 {
577 	bool_t out = FALSE;
578 	enum clnt_stat stat;
579 
580 	if (children >= MAX_CHILDREN || ypdb->dom_broadcast_pid)
581 		return;
582 
583 	if (pipe(ypdb->dom_pipe_fds) < 0) {
584 		syslog(LOG_WARNING, "pipe: %s",strerror(errno));
585 		return;
586 	}
587 
588 	if (ypdb->dom_vers = -1 && (long)ypdb->dom_server_addr.sin_addr.s_addr)
589 		syslog(LOG_WARNING, "NIS server [%s] for domain \"%s\" not responding",
590 		inet_ntoa(ypdb->dom_server_addr.sin_addr), ypdb->dom_domain);
591 
592 	broad_domain = ypdb;
593 	flock(ypdb->dom_lockfd, LOCK_UN);
594 
595 	switch((ypdb->dom_broadcast_pid = fork())) {
596 	case 0:
597 		close(READFD);
598 		break;
599 	case -1:
600 		syslog(LOG_WARNING, "fork: %s", strerror(errno));
601 		close(READFD);
602 		close(WRITEFD);
603 		return;
604 	default:
605 		close(WRITEFD);
606 		FD_SET(READFD, &svc_fdset);
607 		children++;
608 		return;
609 	}
610 
611 	/* Release all locks before doing anything else. */
612 	while(ypbindlist) {
613 		close(ypbindlist->dom_lockfd);
614 		ypbindlist = ypbindlist->dom_pnext;
615 	}
616 	close(yplockfd);
617 
618 	stat = clnt_broadcast(YPPROG, YPVERS, YPPROC_DOMAIN_NONACK,
619 	    xdr_domainname, (char *)ypdb->dom_domain, xdr_bool, (char *)&out,
620 	    broadcast_result);
621 
622 	if (stat != RPC_SUCCESS) {
623 		bzero((char *)&ypdb->dom_server_addr,
624 						sizeof(struct sockaddr_in));
625 		if (tell_parent(ypdb->dom_domain, &ypdb->dom_server_addr))
626 			syslog(LOG_WARNING, "lost connection to parent");
627 	}
628 
629 	exit(0);
630 }
631 
632 /*
633  * The right way to check if a server is alive.
634  * Attempt to get a client handle pointing to the server and send a
635  * YPPROC_DOMAIN. If we can't get a handle or we get a reply of FALSE,
636  * we invalidate this binding entry and send out a broadcast to try to
637  * establish a new binding. Note that we treat non-default domains
638  * specially: once bound, we keep tabs on our server, but if it
639  * goes away and fails to respond after one round of broadcasting, we
640  * abandon it until a client specifically references it again. We make
641  * every effort to keep our default domain bound, however, since we
642  * need it to keep the system on its feet.
643  */
644 int
645 ping(ypdb)
646 struct _dom_binding *ypdb;
647 {
648 	bool_t out;
649 	struct timeval interval, timeout;
650 	enum clnt_stat stat;
651 	int rpcsock = RPC_ANYSOCK;
652 	CLIENT *client_handle;
653 	time_t t;
654 
655 	interval.tv_sec = FAIL_THRESHOLD;
656 	interval.tv_usec = 0;
657 	timeout.tv_sec = FAIL_THRESHOLD;
658 	timeout.tv_usec = 0;
659 
660 	if (ypdb->dom_broadcast_pid)
661 		return(1);
662 
663 	if ((client_handle = clntudp_bufcreate(&ypdb->dom_server_addr,
664 		YPPROG, YPVERS, interval, &rpcsock, RPCSMALLMSGSIZE,
665 		RPCSMALLMSGSIZE)) == (CLIENT *)NULL) {
666 		/* Can't get a handle: we're dead. */
667 		ypdb->dom_alive = 0;
668 		ypdb->dom_vers = -1;
669 		broadcast(ypdb);
670 		return(1);
671 	}
672 
673 	if ((stat = clnt_call(client_handle, YPPROC_DOMAIN,
674 		xdr_domainname, (char *)ypdb->dom_domain, xdr_bool,
675 		(char *)&out, timeout)) != RPC_SUCCESS || out == FALSE) {
676 		ypdb->dom_alive = 0;
677 		ypdb->dom_vers = -1;
678 		clnt_destroy(client_handle);
679 		broadcast(ypdb);
680 		return(1);
681 	}
682 
683 	clnt_destroy(client_handle);
684 	return(0);
685 }
686 
687 void rpc_received(dom, raddrp, force)
688 char *dom;
689 struct sockaddr_in *raddrp;
690 int force;
691 {
692 	struct _dom_binding *ypdb, *prev = NULL;
693 	struct iovec iov[2];
694 	struct ypbind_resp ybr;
695 	char path[MAXPATHLEN];
696 	int fd;
697 
698 	/*printf("returned from %s/%d about %s\n", inet_ntoa(raddrp->sin_addr),
699 	       ntohs(raddrp->sin_port), dom);*/
700 
701 	if(dom==NULL)
702 		return;
703 
704 	for(ypdb=ypbindlist; ypdb; ypdb=ypdb->dom_pnext) {
705 		if( strcmp(ypdb->dom_domain, dom) == 0)
706 			break;
707 		prev = ypdb;
708 	}
709 
710 	if (ypdb && force) {
711 		if (ypdb->dom_broadcast_pid) {
712 			kill(ypdb->dom_broadcast_pid, SIGINT);
713 			close(READFD);
714 			FD_CLR(READFD, &fdsr);
715 			FD_CLR(READFD, &svc_fdset);
716 			READFD = WRITEFD = -1;
717 		}
718 	}
719 
720 	/* if in securemode, check originating port number */
721 	if (ypsecuremode && (ntohs(raddrp->sin_port) >= IPPORT_RESERVED)) {
722 	    syslog(LOG_WARNING, "Rejected NIS server on [%s/%d] for domain %s.",
723 		   inet_ntoa(raddrp->sin_addr), ntohs(raddrp->sin_port),
724 		   dom);
725 	    if (ypdb != NULL) {
726 		ypdb->dom_broadcast_pid = 0;
727 		ypdb->dom_alive = 0;
728 	    }
729 	    return;
730 	}
731 
732 	if (raddrp->sin_addr.s_addr == (long)0) {
733 		switch(ypdb->dom_default) {
734 		case 0:
735 			if (prev == NULL)
736 				ypbindlist = ypdb->dom_pnext;
737 			else
738 				prev->dom_pnext = ypdb->dom_pnext;
739 			sprintf(path, "%s/%s.%ld", BINDINGDIR,
740 				ypdb->dom_domain, YPVERS);
741 			close(ypdb->dom_lockfd);
742 			unlink(path);
743 			free(ypdb);
744 			domains--;
745 			return;
746 		case 1:
747 			ypdb->dom_broadcast_pid = 0;
748 			ypdb->dom_alive = 0;
749 			broadcast(ypdb);
750 			return;
751 		default:
752 			break;
753 		}
754 	}
755 
756 	if(ypdb==NULL) {
757 		if (force == 0)
758 			return;
759 		ypdb = (struct _dom_binding *)malloc(sizeof *ypdb);
760 		if (ypdb == NULL) {
761 			syslog(LOG_WARNING, "malloc: %s", strerror(errno));
762 			return;
763 		}
764 		bzero((char *)ypdb, sizeof *ypdb);
765 		strncpy(ypdb->dom_domain, dom, sizeof ypdb->dom_domain);
766 		ypdb->dom_lockfd = -1;
767 		ypdb->dom_default = 0;
768 		ypdb->dom_pnext = ypbindlist;
769 		ypbindlist = ypdb;
770 	}
771 
772 	/* We've recovered from a crash: inform the world. */
773 	if (ypdb->dom_vers = -1 && ypdb->dom_server_addr.sin_addr.s_addr)
774 		syslog(LOG_WARNING, "NIS server [%s] for domain \"%s\" OK",
775 		inet_ntoa(raddrp->sin_addr), ypdb->dom_domain);
776 
777 	bcopy((char *)raddrp, (char *)&ypdb->dom_server_addr,
778 		sizeof ypdb->dom_server_addr);
779 
780 	ypdb->dom_vers = YPVERS;
781 	ypdb->dom_alive = 1;
782 	ypdb->dom_broadcast_pid = 0;
783 
784 	if(ypdb->dom_lockfd != -1)
785 		close(ypdb->dom_lockfd);
786 
787 	sprintf(path, "%s/%s.%ld", BINDINGDIR,
788 		ypdb->dom_domain, ypdb->dom_vers);
789 #ifdef O_SHLOCK
790 	if( (fd=open(path, O_CREAT|O_SHLOCK|O_RDWR|O_TRUNC, 0644)) == -1) {
791 		(void)mkdir(BINDINGDIR, 0755);
792 		if( (fd=open(path, O_CREAT|O_SHLOCK|O_RDWR|O_TRUNC, 0644)) == -1)
793 			return;
794 	}
795 #else
796 	if( (fd=open(path, O_CREAT|O_RDWR|O_TRUNC, 0644)) == -1) {
797 		(void)mkdir(BINDINGDIR, 0755);
798 		if( (fd=open(path, O_CREAT|O_RDWR|O_TRUNC, 0644)) == -1)
799 			return;
800 	}
801 	flock(fd, LOCK_SH);
802 #endif
803 
804 	/*
805 	 * ok, if BINDINGDIR exists, and we can create the binding file,
806 	 * then write to it..
807 	 */
808 	ypdb->dom_lockfd = fd;
809 
810 	iov[0].iov_base = (caddr_t)&(udptransp->xp_port);
811 	iov[0].iov_len = sizeof udptransp->xp_port;
812 	iov[1].iov_base = (caddr_t)&ybr;
813 	iov[1].iov_len = sizeof ybr;
814 
815 	bzero(&ybr, sizeof ybr);
816 	ybr.ypbind_status = YPBIND_SUCC_VAL;
817 	ybr.ypbind_respbody.ypbind_bindinfo.ypbind_binding_addr = raddrp->sin_addr;
818 	ybr.ypbind_respbody.ypbind_bindinfo.ypbind_binding_port = raddrp->sin_port;
819 
820 	if( writev(ypdb->dom_lockfd, iov, 2) != iov[0].iov_len + iov[1].iov_len) {
821 		syslog(LOG_WARNING, "write: %s", strerror(errno));
822 		close(ypdb->dom_lockfd);
823 		ypdb->dom_lockfd = -1;
824 		return;
825 	}
826 }
827