xref: /freebsd/lib/libc/gen/getnetgrent.c (revision 56e53cb8ef000c3ef72337a4095987a932cdedef)
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 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)getnetgrent.c	8.2 (Berkeley) 4/27/95";
37 #endif /* LIBC_SCCS and not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #include "namespace.h"
42 
43 #include <ctype.h>
44 #include <errno.h>
45 #include <netdb.h>
46 #include <nsswitch.h>
47 #include <pthread.h>
48 #include <pthread_np.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <unistd.h>
53 
54 #include "nss_tls.h"
55 
56 #ifdef YP
57 /*
58  * Notes:
59  * We want to be able to use NIS netgroups properly while retaining
60  * the ability to use a local /etc/netgroup file. Unfortunately, you
61  * can't really do both at the same time - at least, not efficiently.
62  * NetBSD deals with this problem by creating a netgroup database
63  * using Berkeley DB (just like the password database) that allows
64  * for lookups using netgroup, netgroup.byuser or netgroup.byhost
65  * searches. This is a neat idea, but I don't have time to implement
66  * something like that now. (I think ultimately it would be nice
67  * if we DB-fied the group and netgroup stuff all in one shot, but
68  * for now I'm satisfied just to have something that works well
69  * without requiring massive code changes.)
70  *
71  * Therefore, to still permit the use of the local file and maintain
72  * optimum NIS performance, we allow for the following conditions:
73  *
74  * - If /etc/netgroup does not exist and NIS is turned on, we use
75  *   NIS netgroups only.
76  *
77  * - If /etc/netgroup exists but is empty, we use NIS netgroups
78  *   only.
79  *
80  * - If /etc/netgroup exists and contains _only_ a '+', we use
81  *   NIS netgroups only.
82  *
83  * - If /etc/netgroup exists, contains locally defined netgroups
84  *   and a '+', we use a mixture of NIS and the local entries.
85  *   This method should return the same NIS data as just using
86  *   NIS alone, but it will be slower if the NIS netgroup database
87  *   is large (innetgr() in particular will suffer since extra
88  *   processing has to be done in order to determine memberships
89  *   using just the raw netgroup data).
90  *
91  * - If /etc/netgroup exists and contains only locally defined
92  *   netgroup entries, we use just those local entries and ignore
93  *   NIS (this is the original, pre-NIS behavior).
94  */
95 
96 #include <rpc/rpc.h>
97 #include <rpcsvc/yp_prot.h>
98 #include <rpcsvc/ypclnt.h>
99 #include <sys/param.h>
100 #include <sys/stat.h>
101 #include <sys/errno.h>
102 static char *_netgr_yp_domain;
103 int _use_only_yp;
104 static int _netgr_yp_enabled;
105 static int _yp_innetgr;
106 #endif
107 
108 #ifndef _PATH_NETGROUP
109 #define _PATH_NETGROUP "/etc/netgroup"
110 #endif
111 
112 enum constants {
113 	NGRP_STORAGE_INITIAL	= 1 << 10, /* 1 KByte */
114 	NGRP_STORAGE_MAX	= 1 << 20, /* 1 MByte */
115 };
116 
117 static const ns_src defaultsrc[] = {
118 	{ NSSRC_COMPAT, NS_SUCCESS },
119 	{ NULL, 0 },
120 };
121 
122 /*
123  * Static Variables and functions used by setnetgrent(), getnetgrent() and
124  * endnetgrent().
125  * There are two linked lists:
126  * - linelist is just used by setnetgrent() to parse the net group file via.
127  *   parse_netgrp()
128  * - netgrp is the list of entries for the current netgroup
129  */
130 struct linelist {
131 	struct linelist	*l_next;	/* Chain ptr. */
132 	int		l_parsed;	/* Flag for cycles */
133 	char		*l_groupname;	/* Name of netgroup */
134 	char		*l_line;	/* Netgroup entrie(s) to be parsed */
135 };
136 
137 struct netgrp {
138 	struct netgrp	*ng_next;	/* Chain ptr */
139 	char		*ng_str[3];	/* Field pointers, see below */
140 };
141 
142 struct netgr_state {
143 	FILE		*st_netf;
144 	struct linelist	*st_linehead;
145 	struct netgrp	*st_nextgrp;
146 	struct netgrp	*st_gr;
147 	char		*st_grname;
148 };
149 
150 #define NG_HOST		0	/* Host name */
151 #define NG_USER		1	/* User name */
152 #define NG_DOM		2	/* and Domain name */
153 
154 static void	netgr_endstate(void *);
155 NSS_TLS_HANDLING(netgr);
156 
157 static int	files_endnetgrent(void *, void *, va_list);
158 static int	files_getnetgrent_r(void *, void *, va_list);
159 static int	files_setnetgrent(void *, void *, va_list);
160 
161 static int	compat_endnetgrent(void *, void *, va_list);
162 static int	compat_innetgr(void *, void *, va_list);
163 static int	compat_getnetgrent_r(void *, void *, va_list);
164 static int	compat_setnetgrent(void *, void *, va_list);
165 
166 static void	_compat_clearstate(void);
167 static int	_getnetgrent_r(char **, char **, char **, char *, size_t, int *,
168 		    struct netgr_state *);
169 static int	_innetgr_fallback(void *, void *, const char *, const char *,
170 		    const char *, const char *);
171 static int	innetgr_fallback(void *, void *, va_list);
172 static int	parse_netgrp(const char *, struct netgr_state *, int);
173 static struct linelist *read_for_group(const char *, struct netgr_state *, int);
174 
175 #define	LINSIZ	1024	/* Length of netgroup file line */
176 
177 static const ns_dtab getnetgrent_dtab[] = {
178 	NS_FILES_CB(files_getnetgrent_r, NULL)
179 	NS_COMPAT_CB(compat_getnetgrent_r, NULL)
180 	{ NULL, NULL, NULL },
181 };
182 
183 static const ns_dtab setnetgrent_dtab[] = {
184 	NS_FILES_CB(files_setnetgrent, NULL)
185 	NS_COMPAT_CB(compat_setnetgrent, NULL)
186 	{ NULL, NULL, NULL },
187 };
188 
189 static const ns_dtab endnetgrent_dtab[] = {
190 	NS_FILES_CB(files_endnetgrent, NULL)
191 	NS_COMPAT_CB(compat_endnetgrent, NULL)
192 	{ NULL, NULL, NULL },
193 };
194 
195 static struct netgr_state compat_state;
196 
197 static void
198 netgr_endstate(void *arg)
199 {
200 	struct linelist *lp, *olp;
201 	struct netgrp *gp, *ogp;
202 	struct netgr_state *st;
203 
204 	st = (struct netgr_state *)arg;
205 	lp = st->st_linehead;
206 	while (lp != NULL) {
207 		olp = lp;
208 		lp = lp->l_next;
209 		free(olp->l_groupname);
210 		free(olp->l_line);
211 		free(olp);
212 	}
213 	st->st_linehead = NULL;
214 	if (st->st_grname != NULL) {
215 		free(st->st_grname);
216 		st->st_grname = NULL;
217 	}
218 	gp = st->st_gr;
219 	while (gp != NULL) {
220 		ogp = gp;
221 		gp = gp->ng_next;
222 		free(ogp->ng_str[NG_HOST]);
223 		free(ogp->ng_str[NG_USER]);
224 		free(ogp->ng_str[NG_DOM]);
225 		free(ogp);
226 	}
227 	st->st_gr = NULL;
228 	st->st_nextgrp = NULL;
229 }
230 
231 static int
232 files_getnetgrent_r(void *retval, void *mdata, va_list ap)
233 {
234 	struct netgr_state *st;
235 	char **hostp, **userp, **domp, *buf;
236 	size_t bufsize;
237 	int *errnop;
238 
239 	hostp = va_arg(ap, char **);
240 	userp = va_arg(ap, char **);
241 	domp = va_arg(ap, char **);
242 	buf = va_arg(ap, char *);
243 	bufsize = va_arg(ap, size_t);
244 	errnop = va_arg(ap, int *);
245 
246 	if (netgr_getstate(&st) != 0)
247 		return (NS_UNAVAIL);
248 
249 	return (_getnetgrent_r(hostp, userp, domp, buf, bufsize, errnop, st));
250 }
251 
252 static int
253 files_setnetgrent(void *retval, void *mdata, va_list ap)
254 {
255 	const ns_src src[] = {
256 		{ NSSRC_FILES, NS_SUCCESS },
257 		{ NULL, 0 },
258 	};
259 	struct netgr_state *st;
260 	const char *group;
261 	int rv;
262 
263 	group = va_arg(ap, const char *);
264 
265 	if (group == NULL || group[0] == '\0')
266 		return (NS_RETURN);
267 
268 	rv = netgr_getstate(&st);
269 	if (rv != 0)
270 		return (NS_UNAVAIL);
271 
272 	if (st->st_gr == NULL || strcmp(group, st->st_grname) != 0) {
273 		(void)_nsdispatch(NULL, endnetgrent_dtab, NSDB_NETGROUP,
274 		    "endnetgrent", src);
275 		if ((st->st_netf = fopen(_PATH_NETGROUP, "re")) != NULL) {
276 			if (parse_netgrp(group, st, 0) != 0)
277 				(void)_nsdispatch(NULL, endnetgrent_dtab,
278 				    NSDB_NETGROUP, "endnetgrent", src);
279 			else
280 				st->st_grname = strdup(group);
281 			(void)fclose(st->st_netf);
282 			st->st_netf = NULL;
283 		}
284 	}
285 	st->st_nextgrp = st->st_gr;
286 	return (st->st_grname != NULL ? NS_SUCCESS : NS_NOTFOUND);
287 }
288 
289 static int
290 files_endnetgrent(void *retval, void *mdata, va_list ap)
291 {
292 	struct netgr_state *st;
293 
294 	if (netgr_getstate(&st) != 0)
295 		return (NS_UNAVAIL);
296 	netgr_endstate(st);
297 	return (NS_SUCCESS);
298 }
299 
300 static int
301 compat_getnetgrent_r(void *retval, void *mdata, va_list ap)
302 {
303 	char **hostp, **userp, **domp, *buf;
304 	size_t bufsize;
305 	int *errnop;
306 #ifdef YP
307 	_yp_innetgr = 0;
308 #endif
309 
310 	hostp = va_arg(ap, char **);
311 	userp = va_arg(ap, char **);
312 	domp = va_arg(ap, char **);
313 	buf = va_arg(ap, char *);
314 	bufsize = va_arg(ap, size_t);
315 	errnop = va_arg(ap, int *);
316 
317 	return (_getnetgrent_r(hostp, userp, domp, buf, bufsize, errnop,
318 	    &compat_state));
319 }
320 
321 /*
322  * compat_setnetgrent()
323  * Parse the netgroup file looking for the netgroup and build the list
324  * of netgrp structures. Let parse_netgrp() and read_for_group() do
325  * most of the work.
326  */
327 static int
328 compat_setnetgrent(void *retval, void *mdata, va_list ap)
329 {
330 	FILE *netf;
331 	const char *group;
332 #ifdef YP
333 	struct stat _yp_statp;
334 	char _yp_plus;
335 #endif
336 
337 	group = va_arg(ap, const char *);
338 
339 	/* Sanity check */
340 	if (group == NULL || !strlen(group))
341 		return (NS_RETURN);
342 
343 	if (compat_state.st_gr == NULL ||
344 	    strcmp(group, compat_state.st_grname) != 0) {
345 		_compat_clearstate();
346 
347 #ifdef YP
348 		/* Presumed guilty until proven innocent. */
349 		_use_only_yp = 0;
350 		/*
351 		 * If /etc/netgroup doesn't exist or is empty,
352 		 * use NIS exclusively.
353 		 */
354 		if (((stat(_PATH_NETGROUP, &_yp_statp) < 0) &&
355 		    errno == ENOENT) || _yp_statp.st_size == 0)
356 			_use_only_yp = _netgr_yp_enabled = 1;
357 		if ((netf = fopen(_PATH_NETGROUP,"re")) != NULL ||_use_only_yp){
358 			compat_state.st_netf = netf;
359 		/*
360 		 * Icky: grab the first character of the netgroup file
361 		 * and turn on NIS if it's a '+'. rewind the stream
362 		 * afterwards so we don't goof up read_for_group() later.
363 		 */
364 			if (netf) {
365 				fscanf(netf, "%c", &_yp_plus);
366 				rewind(netf);
367 				if (_yp_plus == '+')
368 					_use_only_yp = _netgr_yp_enabled = 1;
369 			}
370 		/*
371 		 * If we were called specifically for an innetgr()
372 		 * lookup and we're in NIS-only mode, short-circuit
373 		 * parse_netgroup() and cut directly to the chase.
374 		 */
375 			if (_use_only_yp && _yp_innetgr) {
376 				/* dohw! */
377 				if (netf != NULL)
378 					fclose(netf);
379 				return (NS_RETURN);
380 			}
381 #else
382 		if ((netf = fopen(_PATH_NETGROUP, "re"))) {
383 			compat_state.st_netf = netf;
384 #endif
385 			if (parse_netgrp(group, &compat_state, 1)) {
386 				_compat_clearstate();
387 			} else {
388 				compat_state.st_grname = strdup(group);
389 			}
390 			if (netf)
391 				fclose(netf);
392 		}
393 	}
394 	compat_state.st_nextgrp = compat_state.st_gr;
395 	return (NS_SUCCESS);
396 }
397 
398 static void
399 _compat_clearstate(void)
400 {
401 
402 #ifdef YP
403 	_netgr_yp_enabled = 0;
404 #endif
405 	netgr_endstate(&compat_state);
406 }
407 
408 /*
409  * compat_endnetgrent() - cleanup
410  */
411 static int
412 compat_endnetgrent(void *retval, void *mdata, va_list ap)
413 {
414 
415 	_compat_clearstate();
416 	return (NS_SUCCESS);
417 }
418 
419 int
420 _getnetgrent_r(char **hostp, char **userp, char **domp, char *buf,
421     size_t bufsize, int *errnop, struct netgr_state *st)
422 {
423 	char *p, *src;
424 	size_t len;
425 	int rv;
426 
427 #define	COPY_NG_ELEM(dstp, i) do {					\
428 	src = st->st_nextgrp->ng_str[(i)];				\
429 	if (src == NULL)						\
430 		src = "";						\
431 	len = strlcpy(p, src, bufsize);					\
432 	if (len >= bufsize) {						\
433 		*errnop = ERANGE;					\
434 		return (NS_RETURN);					\
435 	}								\
436 	*(dstp) = p;							\
437 	p += len + 1;							\
438 	bufsize -= len + 1;						\
439 } while (0)
440 
441 	p = buf;
442 	if (st->st_nextgrp != NULL) {
443 		COPY_NG_ELEM(hostp, NG_HOST);
444 		COPY_NG_ELEM(userp, NG_USER);
445 		COPY_NG_ELEM(domp, NG_DOM);
446 		st->st_nextgrp = st->st_nextgrp->ng_next;
447 		rv = NS_SUCCESS;
448 	} else {
449 		rv = NS_NOTFOUND;
450 	}
451 #undef COPY_NG_ELEM
452 
453 	return (rv);
454 }
455 
456 #ifdef YP
457 static int
458 _listmatch(const char *list, const char *group, int len)
459 {
460 	const char *ptr = list;
461 	const char *cptr;
462 	int glen = strlen(group);
463 
464 	/* skip possible leading whitespace */
465 	while (isspace((unsigned char)*ptr))
466 		ptr++;
467 
468 	while (ptr < list + len) {
469 		cptr = ptr;
470 		while(*ptr != ','  && *ptr != '\0' && !isspace((unsigned char)*ptr))
471 			ptr++;
472 		if (strncmp(cptr, group, glen) == 0 && glen == (ptr - cptr))
473 			return (1);
474 		while (*ptr == ','  || isspace((unsigned char)*ptr))
475 			ptr++;
476 	}
477 
478 	return (0);
479 }
480 
481 static int
482 _revnetgr_lookup(char* lookupdom, char* map, const char* str,
483 		 const char* dom, const char* group)
484 {
485 	int y, rv, rot;
486 	char key[MAXHOSTNAMELEN];
487 	char *result;
488 	int resultlen;
489 
490 	for (rot = 0; ; rot++) {
491 		switch (rot) {
492 		case 0:
493 			snprintf(key, MAXHOSTNAMELEN, "%s.%s", str,
494 			    dom ? dom : lookupdom);
495 			break;
496 		case 1:
497 			snprintf(key, MAXHOSTNAMELEN, "%s.*", str);
498 			break;
499 		case 2:
500 			snprintf(key, MAXHOSTNAMELEN, "*.%s",
501 			    dom ? dom : lookupdom);
502 			break;
503 		case 3:
504 			snprintf(key, MAXHOSTNAMELEN, "*.*");
505 			break;
506 		default:
507 			return (0);
508 		}
509 		y = yp_match(lookupdom, map, key, strlen(key), &result,
510 		    &resultlen);
511 		if (y == 0) {
512 			rv = _listmatch(result, group, resultlen);
513 			free(result);
514 			if (rv)
515 				return (1);
516 		} else if (y != YPERR_KEY) {
517 			/*
518 			 * If we get an error other than 'no
519 			 * such key in map' then something is
520 			 * wrong and we should stop the search.
521 			 */
522 			return (-1);
523 		}
524 	}
525 }
526 #endif
527 
528 /*
529  * Search for a match in a netgroup.
530  */
531 static int
532 compat_innetgr(void *retval, void *mdata, va_list ap)
533 {
534 #ifdef YP
535 	const ns_src src[] = {
536 		{ mdata, NS_SUCCESS },
537 		{ NULL, 0 },
538 	};
539 #endif
540 	const char *group, *host, *user, *dom;
541 
542 	group = va_arg(ap, const char *);
543 	host = va_arg(ap, const char *);
544 	user = va_arg(ap, const char *);
545 	dom = va_arg(ap, const char *);
546 
547 	if (group == NULL || !strlen(group))
548 		return (NS_RETURN);
549 
550 #ifdef YP
551 	_yp_innetgr = 1;
552 	(void)_nsdispatch(NULL, setnetgrent_dtab, NSDB_NETGROUP, "setnetgrent",
553 	    src, group);
554 	_yp_innetgr = 0;
555 	/*
556 	 * If we're in NIS-only mode, do the search using
557 	 * NIS 'reverse netgroup' lookups.
558 	 *
559 	 * What happens with 'reverse netgroup' lookups:
560 	 *
561 	 * 1) try 'reverse netgroup' lookup
562 	 *    1.a) if host is specified and user is null:
563 	 *         look in netgroup.byhost
564 	 *         (try host.domain, host.*, *.domain or *.*)
565 	 *         if found, return yes
566 	 *    1.b) if user is specified and host is null:
567 	 *         look in netgroup.byuser
568 	 *         (try host.domain, host.*, *.domain or *.*)
569 	 *         if found, return yes
570 	 *    1.c) if both host and user are specified,
571 	 *         don't do 'reverse netgroup' lookup.  It won't work.
572 	 *    1.d) if neither host ane user are specified (why?!?)
573 	 *         don't do 'reverse netgroup' lookup either.
574 	 * 2) if domain is specified and 'reverse lookup' is done:
575 	 *    'reverse lookup' was authoritative.  bye bye.
576 	 * 3) otherwise, too bad, try it the slow way.
577 	 */
578 	if (_use_only_yp && (host == NULL) != (user == NULL)) {
579 		int ret;
580 		if(yp_get_default_domain(&_netgr_yp_domain))
581 			return (NS_NOTFOUND);
582 		ret = _revnetgr_lookup(_netgr_yp_domain,
583 				      host?"netgroup.byhost":"netgroup.byuser",
584 				      host?host:user, dom, group);
585 		if (ret == 1) {
586 			*(int *)retval = 1;
587 			return (NS_SUCCESS);
588 		} else if (ret == 0 && dom != NULL) {
589 			*(int *)retval = 0;
590 			return (NS_SUCCESS);
591 		}
592 	}
593 #endif /* YP */
594 
595 	return (_innetgr_fallback(retval, mdata, group, host, user, dom));
596 }
597 
598 static int
599 _innetgr_fallback(void *retval, void *mdata, const char *group, const char *host,
600     const char *user, const char *dom)
601 {
602 	const ns_src src[] = {
603 		{ mdata, NS_SUCCESS },
604 		{ NULL, 0 },
605 	};
606 	char *h, *u, *d;
607 	char *buf;
608 	size_t bufsize;
609 	int rv, ret_errno;
610 
611 	if (group == NULL || group[0] == '\0')
612 		return (NS_RETURN);
613 
614 	bufsize = NGRP_STORAGE_INITIAL;
615 	buf = malloc(bufsize);
616 	if (buf == NULL)
617 		return (NS_UNAVAIL);
618 
619 	*(int *)retval = 0;
620 
621 	(void)_nsdispatch(NULL, setnetgrent_dtab, NSDB_NETGROUP, "setnetgrent",
622 	    src, group);
623 
624 	for (;;) {
625 		do {
626 			ret_errno = 0;
627 			rv = _nsdispatch(NULL, getnetgrent_dtab, NSDB_NETGROUP,
628 			    "getnetgrent_r", src, &h, &u, &d, buf, bufsize,
629 			    &ret_errno);
630 			if (rv != NS_SUCCESS && ret_errno == ERANGE) {
631 				bufsize *= 2;
632 				if (bufsize > NGRP_STORAGE_MAX ||
633 				    (buf = reallocf(buf, bufsize)) == NULL)
634 					goto out;
635 			}
636 		} while (rv != NS_SUCCESS && ret_errno == ERANGE);
637 
638 		if (rv != NS_SUCCESS) {
639 			if (rv == NS_NOTFOUND && ret_errno == 0)
640 				rv = NS_SUCCESS;
641 			break;
642 		}
643 
644 		if ((host == NULL || h == NULL || strcmp(host, h) == 0) &&
645 		    (user == NULL || u == NULL || strcmp(user, u) == 0) &&
646 		    (dom == NULL || d == NULL || strcmp(dom, d) == 0)) {
647 			*(int *)retval = 1;
648 			break;
649 		}
650 	}
651 
652 out:
653 	free(buf);
654 	(void)_nsdispatch(NULL, endnetgrent_dtab, NSDB_NETGROUP, "endnetgrent",
655 	    src);
656 	return (rv);
657 }
658 
659 static int
660 innetgr_fallback(void *retval, void *mdata, va_list ap)
661 {
662 	const char *group, *host, *user, *dom;
663 
664 	group = va_arg(ap, const char *);
665 	host = va_arg(ap, const char *);
666 	user = va_arg(ap, const char *);
667 	dom = va_arg(ap, const char *);
668 
669 	return (_innetgr_fallback(retval, mdata, group, host, user, dom));
670 }
671 
672 /*
673  * Parse the netgroup file setting up the linked lists.
674  */
675 static int
676 parse_netgrp(const char *group, struct netgr_state *st, int niscompat)
677 {
678 	struct netgrp *grp;
679 	struct linelist *lp = st->st_linehead;
680 	char **ng;
681 	char *epos, *gpos, *pos, *spos;
682 	int freepos, len, strpos;
683 #ifdef DEBUG
684 	int fields;
685 #endif
686 
687 	/*
688 	 * First, see if the line has already been read in.
689 	 */
690 	while (lp) {
691 		if (!strcmp(group, lp->l_groupname))
692 			break;
693 		lp = lp->l_next;
694 	}
695 	if (lp == NULL && (lp = read_for_group(group, st, niscompat)) == NULL)
696 		return (1);
697 	if (lp->l_parsed) {
698 #ifdef DEBUG
699 		/*
700 		 * This error message is largely superflous since the
701 		 * code handles the error condition sucessfully, and
702 		 * spewing it out from inside libc can actually hose
703 		 * certain programs.
704 		 */
705 		fprintf(stderr, "Cycle in netgroup %s\n", lp->l_groupname);
706 #endif
707 		return (1);
708 	} else
709 		lp->l_parsed = 1;
710 	pos = lp->l_line;
711 	/* Watch for null pointer dereferences, dammit! */
712 	while (pos != NULL && *pos != '\0') {
713 		if (*pos == '(') {
714 			grp = malloc(sizeof(*grp));
715 			if (grp == NULL)
716 				return (1);
717 			ng = grp->ng_str;
718 			bzero(grp, sizeof(*grp));
719 			pos++;
720 			gpos = strsep(&pos, ")");
721 #ifdef DEBUG
722 			fields = 0;
723 #endif
724 			for (strpos = 0; strpos < 3; strpos++) {
725 				if ((spos = strsep(&gpos, ",")) == NULL) {
726 					/*
727 					 * All other systems I've tested
728 					 * return NULL for empty netgroup
729 					 * fields. It's up to user programs
730 					 * to handle the NULLs appropriately.
731 					 */
732 					ng[strpos] = NULL;
733 					continue;
734 				}
735 #ifdef DEBUG
736 				fields++;
737 #endif
738 				while (*spos == ' ' || *spos == '\t')
739 					spos++;
740 				if ((epos = strpbrk(spos, " \t"))) {
741 					*epos = '\0';
742 					len = epos - spos;
743 				} else
744 					len = strlen(spos);
745 				if (len <= 0)
746 					continue;
747 				ng[strpos] = malloc(len + 1);
748 				if (ng[strpos] == NULL) {
749 					for (freepos = 0; freepos < strpos;
750 					    freepos++)
751 						free(ng[freepos]);
752 					free(grp);
753 					return (1);
754 				}
755 				bcopy(spos, ng[strpos], len + 1);
756 			}
757 			grp->ng_next = st->st_gr;
758 			st->st_gr = grp;
759 #ifdef DEBUG
760 			/*
761 			 * Note: on other platforms, malformed netgroup
762 			 * entries are not normally flagged. While we
763 			 * can catch bad entries and report them, we should
764 			 * stay silent by default for compatibility's sake.
765 			 */
766 			if (fields < 3) {
767 				fprintf(stderr,
768 				"Bad entry (%s%s%s%s%s) in netgroup \"%s\"\n",
769 				    ng[NG_HOST] == NULL ? "" : ng[NG_HOST],
770 				    ng[NG_USER] == NULL ? "" : ",",
771 				    ng[NG_USER] == NULL ? "" : ng[NG_USER],
772 				    ng[NG_DOM] == NULL ? "" : ",",
773 				    ng[NG_DOM] == NULL ? "" : ng[NG_DOM],
774 				    lp->l_groupname);
775 			}
776 #endif
777 		} else {
778 			spos = strsep(&pos, ", \t");
779 			if (parse_netgrp(spos, st, niscompat))
780 				continue;
781 		}
782 		if (pos == NULL)
783 			break;
784 		while (*pos == ' ' || *pos == ',' || *pos == '\t')
785 			pos++;
786 	}
787 	return (0);
788 }
789 
790 /*
791  * Read the netgroup file and save lines until the line for the netgroup
792  * is found. Return 1 if eof is encountered.
793  */
794 static struct linelist *
795 read_for_group(const char *group, struct netgr_state *st, int niscompat)
796 {
797 	char *linep, *olinep, *pos, *spos;
798 	int len, olen;
799 	int cont;
800 	struct linelist *lp;
801 	char line[LINSIZ + 2];
802 	FILE *netf;
803 #ifdef YP
804 	char *result;
805 	int resultlen;
806 	linep = NULL;
807 
808 	netf = st->st_netf;
809 	while ((_netgr_yp_enabled && niscompat) ||
810 	    fgets(line, LINSIZ, netf) != NULL) {
811 		if (_netgr_yp_enabled) {
812 			if(!_netgr_yp_domain)
813 				if(yp_get_default_domain(&_netgr_yp_domain))
814 					continue;
815 			if (yp_match(_netgr_yp_domain, "netgroup", group,
816 			    strlen(group), &result, &resultlen)) {
817 				free(result);
818 				if (_use_only_yp)
819 					return ((struct linelist *)0);
820 				else {
821 					_netgr_yp_enabled = 0;
822 					continue;
823 				}
824 			}
825 			if (strlen(result) == 0) {
826 				free(result);
827 				return (NULL);
828 			}
829 			snprintf(line, LINSIZ, "%s %s", group, result);
830 			free(result);
831 		}
832 #else
833 	linep = NULL;
834 	while (fgets(line, LINSIZ, netf) != NULL) {
835 #endif
836 		pos = (char *)&line;
837 #ifdef YP
838 		if (niscompat && *pos == '+') {
839 			_netgr_yp_enabled = 1;
840 			continue;
841 		}
842 #endif
843 		if (*pos == '#')
844 			continue;
845 		while (*pos == ' ' || *pos == '\t')
846 			pos++;
847 		spos = pos;
848 		while (*pos != ' ' && *pos != '\t' && *pos != '\n' &&
849 			*pos != '\0')
850 			pos++;
851 		len = pos - spos;
852 		while (*pos == ' ' || *pos == '\t')
853 			pos++;
854 		if (*pos != '\n' && *pos != '\0') {
855 			lp = malloc(sizeof (*lp));
856 			if (lp == NULL)
857 				return (NULL);
858 			lp->l_parsed = 0;
859 			lp->l_groupname = malloc(len + 1);
860 			if (lp->l_groupname == NULL) {
861 				free(lp);
862 				return (NULL);
863 			}
864 			bcopy(spos, lp->l_groupname, len);
865 			*(lp->l_groupname + len) = '\0';
866 			len = strlen(pos);
867 			olen = 0;
868 
869 			/*
870 			 * Loop around handling line continuations.
871 			 */
872 			do {
873 				if (*(pos + len - 1) == '\n')
874 					len--;
875 				if (*(pos + len - 1) == '\\') {
876 					len--;
877 					cont = 1;
878 				} else
879 					cont = 0;
880 				if (len > 0) {
881 					linep = malloc(olen + len + 1);
882 					if (linep == NULL) {
883 						free(lp->l_groupname);
884 						free(lp);
885 						if (olen > 0)
886 							free(olinep);
887 						return (NULL);
888 					}
889 					if (olen > 0) {
890 						bcopy(olinep, linep, olen);
891 						free(olinep);
892 					}
893 					bcopy(pos, linep + olen, len);
894 					olen += len;
895 					*(linep + olen) = '\0';
896 					olinep = linep;
897 				}
898 				if (cont) {
899 					if (fgets(line, LINSIZ, netf)) {
900 						pos = line;
901 						len = strlen(pos);
902 					} else
903 						cont = 0;
904 				}
905 			} while (cont);
906 			lp->l_line = linep;
907 			lp->l_next = st->st_linehead;
908 			st->st_linehead = lp;
909 
910 			/*
911 			 * If this is the one we wanted, we are done.
912 			 */
913 			if (!strcmp(lp->l_groupname, group))
914 				return (lp);
915 		}
916 	}
917 #ifdef YP
918 	/*
919 	 * Yucky. The recursive nature of this whole mess might require
920 	 * us to make more than one pass through the netgroup file.
921 	 * This might be best left outside the #ifdef YP, but YP is
922 	 * defined by default anyway, so I'll leave it like this
923 	 * until I know better.
924 	 */
925 	rewind(netf);
926 #endif
927 	return (NULL);
928 }
929 
930 int
931 getnetgrent_r(char **hostp, char **userp, char **domp, char *buf, size_t bufsize)
932 {
933 	int rv, ret_errno;
934 
935 	ret_errno = 0;
936 	rv = _nsdispatch(NULL, getnetgrent_dtab, NSDB_NETGROUP, "getnetgrent_r",
937 	    defaultsrc, hostp, userp, domp, buf, bufsize, &ret_errno);
938 	if (rv == NS_SUCCESS) {
939 		return (1);
940 	} else {
941 		errno = ret_errno;
942 		return (0);
943 	}
944 }
945 
946 int
947 getnetgrent(char **hostp, char **userp, char **domp)
948 {
949 	static char *ngrp_storage;
950 	static size_t ngrp_storage_size;
951 	int ret_errno, rv;
952 
953 	if (ngrp_storage == NULL) {
954 		ngrp_storage_size = NGRP_STORAGE_INITIAL;
955 		ngrp_storage = malloc(ngrp_storage_size);
956 		if (ngrp_storage == NULL)
957 			return (0);
958 	}
959 
960 	do {
961 		ret_errno = 0;
962 		rv = _nsdispatch(NULL, getnetgrent_dtab, NSDB_NETGROUP,
963 		    "getnetgrent_r", defaultsrc, hostp, userp, domp,
964 		    ngrp_storage, ngrp_storage_size, &ret_errno);
965 		if (rv != NS_SUCCESS && ret_errno == ERANGE) {
966 			ngrp_storage_size *= 2;
967 			if (ngrp_storage_size > NGRP_STORAGE_MAX) {
968 				free(ngrp_storage);
969 				ngrp_storage = NULL;
970 				errno = ERANGE;
971 				return (0);
972 			}
973 			ngrp_storage = reallocf(ngrp_storage,
974 			    ngrp_storage_size);
975 			if (ngrp_storage == NULL)
976 				return (0);
977 		}
978 	} while (rv != NS_SUCCESS && ret_errno == ERANGE);
979 
980 	if (rv == NS_SUCCESS) {
981 		return (1);
982 	} else {
983 		errno = ret_errno;
984 		return (0);
985 	}
986 }
987 
988 void
989 setnetgrent(const char *netgroup)
990 {
991 
992 	(void)_nsdispatch(NULL, setnetgrent_dtab, NSDB_NETGROUP, "setnetgrent",
993 	    defaultsrc, netgroup);
994 }
995 
996 void
997 endnetgrent(void)
998 {
999 
1000 	(void)_nsdispatch(NULL, endnetgrent_dtab, NSDB_NETGROUP, "endnetgrent",
1001 	    defaultsrc);
1002 }
1003 
1004 int
1005 innetgr(const char *netgroup, const char *host, const char *user,
1006     const char *domain)
1007 {
1008 	static const ns_dtab dtab[] = {
1009 		NS_COMPAT_CB(compat_innetgr, NULL)
1010 		NS_FALLBACK_CB(innetgr_fallback)
1011 		{ NULL, NULL, NULL },
1012 	};
1013 	int result, rv;
1014 
1015 	rv = _nsdispatch(&result, dtab, NSDB_NETGROUP, "innetgr", defaultsrc,
1016 	    netgroup, host, user, domain);
1017 	return (rv == NS_SUCCESS ? result : 0);
1018 }
1019