xref: /freebsd/lib/libc/gen/getnetgrent.c (revision dc36d6f9bb1753f3808552f3afd30eda9a7b206a)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Rick Macklem at The University of Guelph.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include "namespace.h"
36 
37 #include <ctype.h>
38 #include <errno.h>
39 #include <netdb.h>
40 #include <nsswitch.h>
41 #include <pthread.h>
42 #include <pthread_np.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <unistd.h>
47 
48 #include "nss_tls.h"
49 
50 #ifdef YP
51 /*
52  * Notes:
53  * We want to be able to use NIS netgroups properly while retaining
54  * the ability to use a local /etc/netgroup file. Unfortunately, you
55  * can't really do both at the same time - at least, not efficiently.
56  * NetBSD deals with this problem by creating a netgroup database
57  * using Berkeley DB (just like the password database) that allows
58  * for lookups using netgroup, netgroup.byuser or netgroup.byhost
59  * searches. This is a neat idea, but I don't have time to implement
60  * something like that now. (I think ultimately it would be nice
61  * if we DB-fied the group and netgroup stuff all in one shot, but
62  * for now I'm satisfied just to have something that works well
63  * without requiring massive code changes.)
64  *
65  * Therefore, to still permit the use of the local file and maintain
66  * optimum NIS performance, we allow for the following conditions:
67  *
68  * - If /etc/netgroup does not exist and NIS is turned on, we use
69  *   NIS netgroups only.
70  *
71  * - If /etc/netgroup exists but is empty, we use NIS netgroups
72  *   only.
73  *
74  * - If /etc/netgroup exists and contains _only_ a '+', we use
75  *   NIS netgroups only.
76  *
77  * - If /etc/netgroup exists, contains locally defined netgroups
78  *   and a '+', we use a mixture of NIS and the local entries.
79  *   This method should return the same NIS data as just using
80  *   NIS alone, but it will be slower if the NIS netgroup database
81  *   is large (innetgr() in particular will suffer since extra
82  *   processing has to be done in order to determine memberships
83  *   using just the raw netgroup data).
84  *
85  * - If /etc/netgroup exists and contains only locally defined
86  *   netgroup entries, we use just those local entries and ignore
87  *   NIS (this is the original, pre-NIS behavior).
88  */
89 
90 #include <rpc/rpc.h>
91 #include <rpcsvc/yp_prot.h>
92 #include <rpcsvc/ypclnt.h>
93 #include <sys/param.h>
94 #include <sys/stat.h>
95 #include <sys/errno.h>
96 static char *_netgr_yp_domain;
97 int _use_only_yp;
98 static int _netgr_yp_enabled;
99 static int _yp_innetgr;
100 #endif
101 
102 #ifndef _PATH_NETGROUP
103 #define _PATH_NETGROUP "/etc/netgroup"
104 #endif
105 
106 enum constants {
107 	NGRP_STORAGE_INITIAL	= 1 << 10, /* 1 KByte */
108 	NGRP_STORAGE_MAX	= 1 << 20, /* 1 MByte */
109 };
110 
111 static const ns_src defaultsrc[] = {
112 	{ NSSRC_COMPAT, NS_SUCCESS },
113 	{ NULL, 0 },
114 };
115 
116 /*
117  * Static Variables and functions used by setnetgrent(), getnetgrent() and
118  * endnetgrent().
119  * There are two linked lists:
120  * - linelist is just used by setnetgrent() to parse the net group file via.
121  *   parse_netgrp()
122  * - netgrp is the list of entries for the current netgroup
123  */
124 struct linelist {
125 	struct linelist	*l_next;	/* Chain ptr. */
126 	int		l_parsed;	/* Flag for cycles */
127 	char		*l_groupname;	/* Name of netgroup */
128 	char		*l_line;	/* Netgroup entrie(s) to be parsed */
129 };
130 
131 struct netgrp {
132 	struct netgrp	*ng_next;	/* Chain ptr */
133 	char		*ng_str[3];	/* Field pointers, see below */
134 };
135 
136 struct netgr_state {
137 	FILE		*st_netf;
138 	struct linelist	*st_linehead;
139 	struct netgrp	*st_nextgrp;
140 	struct netgrp	*st_gr;
141 	char		*st_grname;
142 };
143 
144 #define NG_HOST		0	/* Host name */
145 #define NG_USER		1	/* User name */
146 #define NG_DOM		2	/* and Domain name */
147 
148 static void	netgr_endstate(void *);
149 NSS_TLS_HANDLING(netgr);
150 
151 static int	files_endnetgrent(void *, void *, va_list);
152 static int	files_getnetgrent_r(void *, void *, va_list);
153 static int	files_setnetgrent(void *, void *, va_list);
154 
155 static int	compat_endnetgrent(void *, void *, va_list);
156 static int	compat_innetgr(void *, void *, va_list);
157 static int	compat_getnetgrent_r(void *, void *, va_list);
158 static int	compat_setnetgrent(void *, void *, va_list);
159 
160 static void	_compat_clearstate(void);
161 static int	_getnetgrent_r(char **, char **, char **, char *, size_t, int *,
162 		    struct netgr_state *);
163 static int	_innetgr_fallback(void *, void *, const char *, const char *,
164 		    const char *, const char *);
165 static int	innetgr_fallback(void *, void *, va_list);
166 static int	parse_netgrp(const char *, struct netgr_state *, int);
167 static struct linelist *read_for_group(const char *, struct netgr_state *, int);
168 
169 #define	LINSIZ	1024	/* Length of netgroup file line */
170 
171 static const ns_dtab getnetgrent_dtab[] = {
172 	NS_FILES_CB(files_getnetgrent_r, NULL)
173 	NS_COMPAT_CB(compat_getnetgrent_r, NULL)
174 	{ NULL, NULL, NULL },
175 };
176 
177 static const ns_dtab setnetgrent_dtab[] = {
178 	NS_FILES_CB(files_setnetgrent, NULL)
179 	NS_COMPAT_CB(compat_setnetgrent, NULL)
180 	{ NULL, NULL, NULL },
181 };
182 
183 static const ns_dtab endnetgrent_dtab[] = {
184 	NS_FILES_CB(files_endnetgrent, NULL)
185 	NS_COMPAT_CB(compat_endnetgrent, NULL)
186 	{ NULL, NULL, NULL },
187 };
188 
189 static struct netgr_state compat_state;
190 
191 static void
netgr_endstate(void * arg)192 netgr_endstate(void *arg)
193 {
194 	struct linelist *lp, *olp;
195 	struct netgrp *gp, *ogp;
196 	struct netgr_state *st;
197 
198 	st = (struct netgr_state *)arg;
199 	lp = st->st_linehead;
200 	while (lp != NULL) {
201 		olp = lp;
202 		lp = lp->l_next;
203 		free(olp->l_groupname);
204 		free(olp->l_line);
205 		free(olp);
206 	}
207 	st->st_linehead = NULL;
208 	if (st->st_grname != NULL) {
209 		free(st->st_grname);
210 		st->st_grname = NULL;
211 	}
212 	gp = st->st_gr;
213 	while (gp != NULL) {
214 		ogp = gp;
215 		gp = gp->ng_next;
216 		free(ogp->ng_str[NG_HOST]);
217 		free(ogp->ng_str[NG_USER]);
218 		free(ogp->ng_str[NG_DOM]);
219 		free(ogp);
220 	}
221 	st->st_gr = NULL;
222 	st->st_nextgrp = NULL;
223 }
224 
225 static int
files_getnetgrent_r(void * retval,void * mdata,va_list ap)226 files_getnetgrent_r(void *retval, void *mdata, va_list ap)
227 {
228 	struct netgr_state *st;
229 	char **hostp, **userp, **domp, *buf;
230 	size_t bufsize;
231 	int *errnop;
232 
233 	hostp = va_arg(ap, char **);
234 	userp = va_arg(ap, char **);
235 	domp = va_arg(ap, char **);
236 	buf = va_arg(ap, char *);
237 	bufsize = va_arg(ap, size_t);
238 	errnop = va_arg(ap, int *);
239 
240 	if (netgr_getstate(&st) != 0)
241 		return (NS_UNAVAIL);
242 
243 	return (_getnetgrent_r(hostp, userp, domp, buf, bufsize, errnop, st));
244 }
245 
246 static int
files_setnetgrent(void * retval,void * mdata,va_list ap)247 files_setnetgrent(void *retval, void *mdata, va_list ap)
248 {
249 	const ns_src src[] = {
250 		{ NSSRC_FILES, NS_SUCCESS },
251 		{ NULL, 0 },
252 	};
253 	struct netgr_state *st;
254 	const char *group;
255 	int rv;
256 
257 	group = va_arg(ap, const char *);
258 
259 	if (group == NULL || group[0] == '\0')
260 		return (NS_RETURN);
261 
262 	rv = netgr_getstate(&st);
263 	if (rv != 0)
264 		return (NS_UNAVAIL);
265 
266 	if (st->st_gr == NULL || strcmp(group, st->st_grname) != 0) {
267 		(void)_nsdispatch(NULL, endnetgrent_dtab, NSDB_NETGROUP,
268 		    "endnetgrent", src);
269 		if ((st->st_netf = fopen(_PATH_NETGROUP, "re")) != NULL) {
270 			if (parse_netgrp(group, st, 0) != 0)
271 				(void)_nsdispatch(NULL, endnetgrent_dtab,
272 				    NSDB_NETGROUP, "endnetgrent", src);
273 			else
274 				st->st_grname = strdup(group);
275 			(void)fclose(st->st_netf);
276 			st->st_netf = NULL;
277 		}
278 	}
279 	st->st_nextgrp = st->st_gr;
280 	return (st->st_grname != NULL ? NS_SUCCESS : NS_NOTFOUND);
281 }
282 
283 static int
files_endnetgrent(void * retval,void * mdata,va_list ap)284 files_endnetgrent(void *retval, void *mdata, va_list ap)
285 {
286 	struct netgr_state *st;
287 
288 	if (netgr_getstate(&st) != 0)
289 		return (NS_UNAVAIL);
290 	netgr_endstate(st);
291 	return (NS_SUCCESS);
292 }
293 
294 static int
compat_getnetgrent_r(void * retval,void * mdata,va_list ap)295 compat_getnetgrent_r(void *retval, void *mdata, va_list ap)
296 {
297 	char **hostp, **userp, **domp, *buf;
298 	size_t bufsize;
299 	int *errnop;
300 #ifdef YP
301 	_yp_innetgr = 0;
302 #endif
303 
304 	hostp = va_arg(ap, char **);
305 	userp = va_arg(ap, char **);
306 	domp = va_arg(ap, char **);
307 	buf = va_arg(ap, char *);
308 	bufsize = va_arg(ap, size_t);
309 	errnop = va_arg(ap, int *);
310 
311 	return (_getnetgrent_r(hostp, userp, domp, buf, bufsize, errnop,
312 	    &compat_state));
313 }
314 
315 /*
316  * compat_setnetgrent()
317  * Parse the netgroup file looking for the netgroup and build the list
318  * of netgrp structures. Let parse_netgrp() and read_for_group() do
319  * most of the work.
320  */
321 static int
compat_setnetgrent(void * retval,void * mdata,va_list ap)322 compat_setnetgrent(void *retval, void *mdata, va_list ap)
323 {
324 	FILE *netf;
325 	const char *group;
326 #ifdef YP
327 	struct stat _yp_statp;
328 	char _yp_plus;
329 #endif
330 
331 	group = va_arg(ap, const char *);
332 
333 	/* Sanity check */
334 	if (group == NULL || !strlen(group))
335 		return (NS_RETURN);
336 
337 	if (compat_state.st_gr == NULL ||
338 	    strcmp(group, compat_state.st_grname) != 0) {
339 		_compat_clearstate();
340 
341 #ifdef YP
342 		/* Presumed guilty until proven innocent. */
343 		_use_only_yp = 0;
344 		/*
345 		 * If /etc/netgroup doesn't exist or is empty,
346 		 * use NIS exclusively.
347 		 */
348 		if (((stat(_PATH_NETGROUP, &_yp_statp) < 0) &&
349 		    errno == ENOENT) || _yp_statp.st_size == 0)
350 			_use_only_yp = _netgr_yp_enabled = 1;
351 		if ((netf = fopen(_PATH_NETGROUP,"re")) != NULL ||_use_only_yp){
352 			compat_state.st_netf = netf;
353 		/*
354 		 * Icky: grab the first character of the netgroup file
355 		 * and turn on NIS if it's a '+'. rewind the stream
356 		 * afterwards so we don't goof up read_for_group() later.
357 		 */
358 			if (netf) {
359 				fscanf(netf, "%c", &_yp_plus);
360 				rewind(netf);
361 				if (_yp_plus == '+')
362 					_use_only_yp = _netgr_yp_enabled = 1;
363 			}
364 		/*
365 		 * If we were called specifically for an innetgr()
366 		 * lookup and we're in NIS-only mode, short-circuit
367 		 * parse_netgroup() and cut directly to the chase.
368 		 */
369 			if (_use_only_yp && _yp_innetgr) {
370 				/* dohw! */
371 				if (netf != NULL)
372 					fclose(netf);
373 				return (NS_RETURN);
374 			}
375 #else
376 		if ((netf = fopen(_PATH_NETGROUP, "re"))) {
377 			compat_state.st_netf = netf;
378 #endif
379 			if (parse_netgrp(group, &compat_state, 1)) {
380 				_compat_clearstate();
381 			} else {
382 				compat_state.st_grname = strdup(group);
383 			}
384 			if (netf)
385 				fclose(netf);
386 		}
387 	}
388 	compat_state.st_nextgrp = compat_state.st_gr;
389 	return (NS_SUCCESS);
390 }
391 
392 static void
393 _compat_clearstate(void)
394 {
395 
396 #ifdef YP
397 	_netgr_yp_enabled = 0;
398 #endif
399 	netgr_endstate(&compat_state);
400 }
401 
402 /*
403  * compat_endnetgrent() - cleanup
404  */
405 static int
406 compat_endnetgrent(void *retval, void *mdata, va_list ap)
407 {
408 
409 	_compat_clearstate();
410 	return (NS_SUCCESS);
411 }
412 
413 int
414 _getnetgrent_r(char **hostp, char **userp, char **domp, char *buf,
415     size_t bufsize, int *errnop, struct netgr_state *st)
416 {
417 	char *p, *src;
418 	size_t len;
419 	int rv;
420 
421 #define	COPY_NG_ELEM(dstp, i) do {					\
422 	src = st->st_nextgrp->ng_str[(i)];				\
423 	if (src == NULL)						\
424 		src = "";						\
425 	len = strlcpy(p, src, bufsize);					\
426 	if (len >= bufsize) {						\
427 		*errnop = ERANGE;					\
428 		return (NS_RETURN);					\
429 	}								\
430 	*(dstp) = p;							\
431 	p += len + 1;							\
432 	bufsize -= len + 1;						\
433 } while (0)
434 
435 	p = buf;
436 	if (st->st_nextgrp != NULL) {
437 		COPY_NG_ELEM(hostp, NG_HOST);
438 		COPY_NG_ELEM(userp, NG_USER);
439 		COPY_NG_ELEM(domp, NG_DOM);
440 		st->st_nextgrp = st->st_nextgrp->ng_next;
441 		rv = NS_SUCCESS;
442 	} else {
443 		rv = NS_NOTFOUND;
444 	}
445 #undef COPY_NG_ELEM
446 
447 	return (rv);
448 }
449 
450 #ifdef YP
451 static int
452 _listmatch(const char *list, const char *group, int len)
453 {
454 	const char *ptr = list;
455 	const char *cptr;
456 	int glen = strlen(group);
457 
458 	/* skip possible leading whitespace */
459 	while (isspace((unsigned char)*ptr))
460 		ptr++;
461 
462 	while (ptr < list + len) {
463 		cptr = ptr;
464 		while(*ptr != ','  && *ptr != '\0' && !isspace((unsigned char)*ptr))
465 			ptr++;
466 		if (strncmp(cptr, group, glen) == 0 && glen == (ptr - cptr))
467 			return (1);
468 		while (*ptr == ','  || isspace((unsigned char)*ptr))
469 			ptr++;
470 	}
471 
472 	return (0);
473 }
474 
475 static int
476 _revnetgr_lookup(char* lookupdom, char* map, const char* str,
477 		 const char* dom, const char* group)
478 {
479 	int y, rv, rot;
480 	char key[MAXHOSTNAMELEN];
481 	char *result;
482 	int resultlen;
483 
484 	for (rot = 0; ; rot++) {
485 		switch (rot) {
486 		case 0:
487 			snprintf(key, MAXHOSTNAMELEN, "%s.%s", str,
488 			    dom ? dom : lookupdom);
489 			break;
490 		case 1:
491 			snprintf(key, MAXHOSTNAMELEN, "%s.*", str);
492 			break;
493 		case 2:
494 			snprintf(key, MAXHOSTNAMELEN, "*.%s",
495 			    dom ? dom : lookupdom);
496 			break;
497 		case 3:
498 			snprintf(key, MAXHOSTNAMELEN, "*.*");
499 			break;
500 		default:
501 			return (0);
502 		}
503 		y = yp_match(lookupdom, map, key, strlen(key), &result,
504 		    &resultlen);
505 		if (y == 0) {
506 			rv = _listmatch(result, group, resultlen);
507 			free(result);
508 			if (rv)
509 				return (1);
510 		} else if (y != YPERR_KEY) {
511 			/*
512 			 * If we get an error other than 'no
513 			 * such key in map' then something is
514 			 * wrong and we should stop the search.
515 			 */
516 			return (-1);
517 		}
518 	}
519 }
520 #endif
521 
522 /*
523  * Search for a match in a netgroup.
524  */
525 static int
526 compat_innetgr(void *retval, void *mdata, va_list ap)
527 {
528 #ifdef YP
529 	const ns_src src[] = {
530 		{ mdata, NS_SUCCESS },
531 		{ NULL, 0 },
532 	};
533 #endif
534 	const char *group, *host, *user, *dom;
535 
536 	group = va_arg(ap, const char *);
537 	host = va_arg(ap, const char *);
538 	user = va_arg(ap, const char *);
539 	dom = va_arg(ap, const char *);
540 
541 	if (group == NULL || !strlen(group))
542 		return (NS_RETURN);
543 
544 #ifdef YP
545 	_yp_innetgr = 1;
546 	(void)_nsdispatch(NULL, setnetgrent_dtab, NSDB_NETGROUP, "setnetgrent",
547 	    src, group);
548 	_yp_innetgr = 0;
549 	/*
550 	 * If we're in NIS-only mode, do the search using
551 	 * NIS 'reverse netgroup' lookups.
552 	 *
553 	 * What happens with 'reverse netgroup' lookups:
554 	 *
555 	 * 1) try 'reverse netgroup' lookup
556 	 *    1.a) if host is specified and user is null:
557 	 *         look in netgroup.byhost
558 	 *         (try host.domain, host.*, *.domain or *.*)
559 	 *         if found, return yes
560 	 *    1.b) if user is specified and host is null:
561 	 *         look in netgroup.byuser
562 	 *         (try host.domain, host.*, *.domain or *.*)
563 	 *         if found, return yes
564 	 *    1.c) if both host and user are specified,
565 	 *         don't do 'reverse netgroup' lookup.  It won't work.
566 	 *    1.d) if neither host ane user are specified (why?!?)
567 	 *         don't do 'reverse netgroup' lookup either.
568 	 * 2) if domain is specified and 'reverse lookup' is done:
569 	 *    'reverse lookup' was authoritative.  bye bye.
570 	 * 3) otherwise, too bad, try it the slow way.
571 	 */
572 	if (_use_only_yp && (host == NULL) != (user == NULL)) {
573 		int ret;
574 		if(yp_get_default_domain(&_netgr_yp_domain))
575 			return (NS_NOTFOUND);
576 		ret = _revnetgr_lookup(_netgr_yp_domain,
577 				      host?"netgroup.byhost":"netgroup.byuser",
578 				      host?host:user, dom, group);
579 		if (ret == 1) {
580 			*(int *)retval = 1;
581 			return (NS_SUCCESS);
582 		} else if (ret == 0 && dom != NULL) {
583 			*(int *)retval = 0;
584 			return (NS_SUCCESS);
585 		}
586 	}
587 #endif /* YP */
588 
589 	return (_innetgr_fallback(retval, mdata, group, host, user, dom));
590 }
591 
592 static int
593 _innetgr_fallback(void *retval, void *mdata, const char *group, const char *host,
594     const char *user, const char *dom)
595 {
596 	const ns_src src[] = {
597 		{ mdata, NS_SUCCESS },
598 		{ NULL, 0 },
599 	};
600 	char *h, *u, *d;
601 	char *buf;
602 	size_t bufsize;
603 	int rv, ret_errno;
604 
605 	if (group == NULL || group[0] == '\0')
606 		return (NS_RETURN);
607 
608 	bufsize = NGRP_STORAGE_INITIAL;
609 	buf = malloc(bufsize);
610 	if (buf == NULL)
611 		return (NS_UNAVAIL);
612 
613 	*(int *)retval = 0;
614 
615 	(void)_nsdispatch(NULL, setnetgrent_dtab, NSDB_NETGROUP, "setnetgrent",
616 	    src, group);
617 
618 	for (;;) {
619 		do {
620 			ret_errno = 0;
621 			rv = _nsdispatch(NULL, getnetgrent_dtab, NSDB_NETGROUP,
622 			    "getnetgrent_r", src, &h, &u, &d, buf, bufsize,
623 			    &ret_errno);
624 			if (rv != NS_SUCCESS && ret_errno == ERANGE) {
625 				bufsize *= 2;
626 				if (bufsize > NGRP_STORAGE_MAX ||
627 				    (buf = reallocf(buf, bufsize)) == NULL)
628 					goto out;
629 			}
630 		} while (rv != NS_SUCCESS && ret_errno == ERANGE);
631 
632 		if (rv != NS_SUCCESS) {
633 			if (rv == NS_NOTFOUND && ret_errno == 0)
634 				rv = NS_SUCCESS;
635 			break;
636 		}
637 
638 		if ((host == NULL || h == NULL || strcmp(host, h) == 0) &&
639 		    (user == NULL || u == NULL || strcmp(user, u) == 0) &&
640 		    (dom == NULL || d == NULL || strcmp(dom, d) == 0)) {
641 			*(int *)retval = 1;
642 			break;
643 		}
644 	}
645 
646 out:
647 	free(buf);
648 	(void)_nsdispatch(NULL, endnetgrent_dtab, NSDB_NETGROUP, "endnetgrent",
649 	    src);
650 	return (rv);
651 }
652 
653 static int
654 innetgr_fallback(void *retval, void *mdata, va_list ap)
655 {
656 	const char *group, *host, *user, *dom;
657 
658 	group = va_arg(ap, const char *);
659 	host = va_arg(ap, const char *);
660 	user = va_arg(ap, const char *);
661 	dom = va_arg(ap, const char *);
662 
663 	return (_innetgr_fallback(retval, mdata, group, host, user, dom));
664 }
665 
666 /*
667  * Parse the netgroup file setting up the linked lists.
668  */
669 static int
670 parse_netgrp(const char *group, struct netgr_state *st, int niscompat)
671 {
672 	struct netgrp *grp;
673 	struct linelist *lp = st->st_linehead;
674 	char **ng;
675 	char *epos, *gpos, *pos, *spos;
676 	int freepos, len, strpos;
677 #ifdef DEBUG
678 	int fields;
679 #endif
680 
681 	/*
682 	 * First, see if the line has already been read in.
683 	 */
684 	while (lp) {
685 		if (!strcmp(group, lp->l_groupname))
686 			break;
687 		lp = lp->l_next;
688 	}
689 	if (lp == NULL && (lp = read_for_group(group, st, niscompat)) == NULL)
690 		return (1);
691 	if (lp->l_parsed) {
692 #ifdef DEBUG
693 		/*
694 		 * This error message is largely superflous since the
695 		 * code handles the error condition sucessfully, and
696 		 * spewing it out from inside libc can actually hose
697 		 * certain programs.
698 		 */
699 		fprintf(stderr, "Cycle in netgroup %s\n", lp->l_groupname);
700 #endif
701 		return (1);
702 	} else
703 		lp->l_parsed = 1;
704 	pos = lp->l_line;
705 	/* Watch for null pointer dereferences, dammit! */
706 	while (pos != NULL && *pos != '\0') {
707 		if (*pos == '(') {
708 			grp = malloc(sizeof(*grp));
709 			if (grp == NULL)
710 				return (1);
711 			ng = grp->ng_str;
712 			bzero(grp, sizeof(*grp));
713 			pos++;
714 			gpos = strsep(&pos, ")");
715 #ifdef DEBUG
716 			fields = 0;
717 #endif
718 			for (strpos = 0; strpos < 3; strpos++) {
719 				if ((spos = strsep(&gpos, ",")) == NULL) {
720 					/*
721 					 * All other systems I've tested
722 					 * return NULL for empty netgroup
723 					 * fields. It's up to user programs
724 					 * to handle the NULLs appropriately.
725 					 */
726 					ng[strpos] = NULL;
727 					continue;
728 				}
729 #ifdef DEBUG
730 				fields++;
731 #endif
732 				while (*spos == ' ' || *spos == '\t')
733 					spos++;
734 				if ((epos = strpbrk(spos, " \t"))) {
735 					*epos = '\0';
736 					len = epos - spos;
737 				} else
738 					len = strlen(spos);
739 				if (len <= 0)
740 					continue;
741 				ng[strpos] = malloc(len + 1);
742 				if (ng[strpos] == NULL) {
743 					for (freepos = 0; freepos < strpos;
744 					    freepos++)
745 						free(ng[freepos]);
746 					free(grp);
747 					return (1);
748 				}
749 				bcopy(spos, ng[strpos], len + 1);
750 			}
751 			grp->ng_next = st->st_gr;
752 			st->st_gr = grp;
753 #ifdef DEBUG
754 			/*
755 			 * Note: on other platforms, malformed netgroup
756 			 * entries are not normally flagged. While we
757 			 * can catch bad entries and report them, we should
758 			 * stay silent by default for compatibility's sake.
759 			 */
760 			if (fields < 3) {
761 				fprintf(stderr,
762 				"Bad entry (%s%s%s%s%s) in netgroup \"%s\"\n",
763 				    ng[NG_HOST] == NULL ? "" : ng[NG_HOST],
764 				    ng[NG_USER] == NULL ? "" : ",",
765 				    ng[NG_USER] == NULL ? "" : ng[NG_USER],
766 				    ng[NG_DOM] == NULL ? "" : ",",
767 				    ng[NG_DOM] == NULL ? "" : ng[NG_DOM],
768 				    lp->l_groupname);
769 			}
770 #endif
771 		} else {
772 			spos = strsep(&pos, ", \t");
773 			if (parse_netgrp(spos, st, niscompat))
774 				continue;
775 		}
776 		if (pos == NULL)
777 			break;
778 		while (*pos == ' ' || *pos == ',' || *pos == '\t')
779 			pos++;
780 	}
781 	return (0);
782 }
783 
784 /*
785  * Read the netgroup file and save lines until the line for the netgroup
786  * is found. Return 1 if eof is encountered.
787  */
788 static struct linelist *
789 read_for_group(const char *group, struct netgr_state *st, int niscompat)
790 {
791 	char *linep, *olinep, *pos, *spos;
792 	int len, olen;
793 	int cont;
794 	struct linelist *lp;
795 	char line[LINSIZ + 2];
796 	FILE *netf;
797 #ifdef YP
798 	char *result;
799 	int resultlen;
800 	linep = NULL;
801 
802 	netf = st->st_netf;
803 	while ((_netgr_yp_enabled && niscompat) ||
804 	    fgets(line, LINSIZ, netf) != NULL) {
805 		if (_netgr_yp_enabled) {
806 			if(!_netgr_yp_domain)
807 				if(yp_get_default_domain(&_netgr_yp_domain))
808 					continue;
809 			if (yp_match(_netgr_yp_domain, "netgroup", group,
810 			    strlen(group), &result, &resultlen)) {
811 				free(result);
812 				if (_use_only_yp)
813 					return ((struct linelist *)0);
814 				else {
815 					_netgr_yp_enabled = 0;
816 					continue;
817 				}
818 			}
819 			if (strlen(result) == 0) {
820 				free(result);
821 				return (NULL);
822 			}
823 			snprintf(line, LINSIZ, "%s %s", group, result);
824 			free(result);
825 		}
826 #else
827 	linep = NULL;
828 	while (fgets(line, LINSIZ, netf) != NULL) {
829 #endif
830 		pos = (char *)&line;
831 #ifdef YP
832 		if (niscompat && *pos == '+') {
833 			_netgr_yp_enabled = 1;
834 			continue;
835 		}
836 #endif
837 		if (*pos == '#')
838 			continue;
839 		while (*pos == ' ' || *pos == '\t')
840 			pos++;
841 		spos = pos;
842 		while (*pos != ' ' && *pos != '\t' && *pos != '\n' &&
843 			*pos != '\0')
844 			pos++;
845 		len = pos - spos;
846 		while (*pos == ' ' || *pos == '\t')
847 			pos++;
848 		if (*pos != '\n' && *pos != '\0') {
849 			lp = malloc(sizeof (*lp));
850 			if (lp == NULL)
851 				return (NULL);
852 			lp->l_parsed = 0;
853 			lp->l_groupname = malloc(len + 1);
854 			if (lp->l_groupname == NULL) {
855 				free(lp);
856 				return (NULL);
857 			}
858 			bcopy(spos, lp->l_groupname, len);
859 			*(lp->l_groupname + len) = '\0';
860 			len = strlen(pos);
861 			olen = 0;
862 
863 			/*
864 			 * Loop around handling line continuations.
865 			 */
866 			do {
867 				if (*(pos + len - 1) == '\n')
868 					len--;
869 				if (*(pos + len - 1) == '\\') {
870 					len--;
871 					cont = 1;
872 				} else
873 					cont = 0;
874 				if (len > 0) {
875 					linep = malloc(olen + len + 1);
876 					if (linep == NULL) {
877 						free(lp->l_groupname);
878 						free(lp);
879 						if (olen > 0)
880 							free(olinep);
881 						return (NULL);
882 					}
883 					if (olen > 0) {
884 						bcopy(olinep, linep, olen);
885 						free(olinep);
886 					}
887 					bcopy(pos, linep + olen, len);
888 					olen += len;
889 					*(linep + olen) = '\0';
890 					olinep = linep;
891 				}
892 				if (cont) {
893 					if (fgets(line, LINSIZ, netf)) {
894 						pos = line;
895 						len = strlen(pos);
896 					} else
897 						cont = 0;
898 				}
899 			} while (cont);
900 			lp->l_line = linep;
901 			lp->l_next = st->st_linehead;
902 			st->st_linehead = lp;
903 
904 			/*
905 			 * If this is the one we wanted, we are done.
906 			 */
907 			if (!strcmp(lp->l_groupname, group))
908 				return (lp);
909 		}
910 	}
911 #ifdef YP
912 	/*
913 	 * Yucky. The recursive nature of this whole mess might require
914 	 * us to make more than one pass through the netgroup file.
915 	 * This might be best left outside the #ifdef YP, but YP is
916 	 * defined by default anyway, so I'll leave it like this
917 	 * until I know better.
918 	 */
919 	rewind(netf);
920 #endif
921 	return (NULL);
922 }
923 
924 int
925 getnetgrent_r(char **hostp, char **userp, char **domp, char *buf, size_t bufsize)
926 {
927 	int rv, ret_errno;
928 
929 	ret_errno = 0;
930 	rv = _nsdispatch(NULL, getnetgrent_dtab, NSDB_NETGROUP, "getnetgrent_r",
931 	    defaultsrc, hostp, userp, domp, buf, bufsize, &ret_errno);
932 	if (rv == NS_SUCCESS) {
933 		return (1);
934 	} else {
935 		errno = ret_errno;
936 		return (0);
937 	}
938 }
939 
940 int
941 getnetgrent(char **hostp, char **userp, char **domp)
942 {
943 	static char *ngrp_storage;
944 	static size_t ngrp_storage_size;
945 	int ret_errno, rv;
946 
947 	if (ngrp_storage == NULL) {
948 		ngrp_storage_size = NGRP_STORAGE_INITIAL;
949 		ngrp_storage = malloc(ngrp_storage_size);
950 		if (ngrp_storage == NULL)
951 			return (0);
952 	}
953 
954 	do {
955 		ret_errno = 0;
956 		rv = _nsdispatch(NULL, getnetgrent_dtab, NSDB_NETGROUP,
957 		    "getnetgrent_r", defaultsrc, hostp, userp, domp,
958 		    ngrp_storage, ngrp_storage_size, &ret_errno);
959 		if (rv != NS_SUCCESS && ret_errno == ERANGE) {
960 			ngrp_storage_size *= 2;
961 			if (ngrp_storage_size > NGRP_STORAGE_MAX) {
962 				free(ngrp_storage);
963 				ngrp_storage = NULL;
964 				errno = ERANGE;
965 				return (0);
966 			}
967 			ngrp_storage = reallocf(ngrp_storage,
968 			    ngrp_storage_size);
969 			if (ngrp_storage == NULL)
970 				return (0);
971 		}
972 	} while (rv != NS_SUCCESS && ret_errno == ERANGE);
973 
974 	if (rv == NS_SUCCESS) {
975 		return (1);
976 	} else {
977 		errno = ret_errno;
978 		return (0);
979 	}
980 }
981 
982 void
983 setnetgrent(const char *netgroup)
984 {
985 
986 	(void)_nsdispatch(NULL, setnetgrent_dtab, NSDB_NETGROUP, "setnetgrent",
987 	    defaultsrc, netgroup);
988 }
989 
990 void
991 endnetgrent(void)
992 {
993 
994 	(void)_nsdispatch(NULL, endnetgrent_dtab, NSDB_NETGROUP, "endnetgrent",
995 	    defaultsrc);
996 }
997 
998 int
999 innetgr(const char *netgroup, const char *host, const char *user,
1000     const char *domain)
1001 {
1002 	static const ns_dtab dtab[] = {
1003 		NS_COMPAT_CB(compat_innetgr, NULL)
1004 		NS_FALLBACK_CB(innetgr_fallback)
1005 		{ NULL, NULL, NULL },
1006 	};
1007 	int result, rv;
1008 
1009 	rv = _nsdispatch(&result, dtab, NSDB_NETGROUP, "innetgr", defaultsrc,
1010 	    netgroup, host, user, domain);
1011 	return (rv == NS_SUCCESS ? result : 0);
1012 }
1013