2 * Copyright (c) 1992, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Rick Macklem at The University of Guelph.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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32 * @(#)getnetgrent.c 8.2 (Berkeley) 4/27/95
33 * $FreeBSD: src/lib/libc/gen/getnetgrent.c,v 1.35 2007/01/09 00:27:54 imp Exp $
34 * $DragonFly: src/lib/libc/gen/getnetgrent.c,v 1.5 2005/04/25 19:03:46 joerg Exp $
47 * We want to be able to use NIS netgroups properly while retaining
48 * the ability to use a local /etc/netgroup file. Unfortunately, you
49 * can't really do both at the same time - at least, not efficiently.
50 * NetBSD deals with this problem by creating a netgroup database
51 * using Berkeley DB (just like the password database) that allows
52 * for lookups using netgroup, netgroup.byuser or netgroup.byhost
53 * searches. This is a neat idea, but I don't have time to implement
54 * something like that now. (I think ultimately it would be nice
55 * if we DB-fied the group and netgroup stuff all in one shot, but
56 * for now I'm satisfied just to have something that works well
57 * without requiring massive code changes.)
59 * Therefore, to still permit the use of the local file and maintain
60 * optimum NIS performance, we allow for the following conditions:
62 * - If /etc/netgroup does not exist and NIS is turned on, we use
65 * - If /etc/netgroup exists but is empty, we use NIS netgroups
68 * - If /etc/netgroup exists and contains _only_ a '+', we use
71 * - If /etc/netgroup exists, contains locally defined netgroups
72 * and a '+', we use a mixture of NIS and the local entries.
73 * This method should return the same NIS data as just using
74 * NIS alone, but it will be slower if the NIS netgroup database
75 * is large (innetgr() in particular will suffer since extra
76 * processing has to be done in order to determine memberships
77 * using just the raw netgroup data).
79 * - If /etc/netgroup exists and contains only locally defined
80 * netgroup entries, we use just those local entries and ignore
81 * NIS (this is the original, pre-NIS behavior).
85 #include <rpcsvc/yp_prot.h>
86 #include <rpcsvc/ypclnt.h>
87 #include <sys/types.h>
89 #include <sys/param.h>
90 #include <sys/errno.h>
91 static char *_netgr_yp_domain;
93 static int _netgr_yp_enabled;
94 static int _yp_innetgr;
97 #ifndef _PATH_NETGROUP
98 #define _PATH_NETGROUP "/etc/netgroup"
102 * Static Variables and functions used by setnetgrent(), getnetgrent() and
104 * There are two linked lists:
105 * - linelist is just used by setnetgrent() to parse the net group file via.
107 * - netgrp is the list of entries for the current netgroup
110 struct linelist *l_next; /* Chain ptr. */
111 int l_parsed; /* Flag for cycles */
112 char *l_groupname; /* Name of netgroup */
113 char *l_line; /* Netgroup entrie(s) to be parsed */
117 struct netgrp *ng_next; /* Chain ptr */
118 char *ng_str[3]; /* Field pointers, see below */
120 #define NG_HOST 0 /* Host name */
121 #define NG_USER 1 /* User name */
122 #define NG_DOM 2 /* and Domain name */
124 static struct linelist *linehead = NULL;
125 static struct netgrp *nextgrp = NULL;
133 static FILE *netf = NULL;
135 static int parse_netgrp(const char *);
136 static struct linelist *read_for_group(const char *);
138 #define LINSIZ 1024 /* Length of netgroup file line */
142 * Parse the netgroup file looking for the netgroup and build the list
143 * of netgrp structures. Let parse_netgrp() and read_for_group() do
147 setnetgrent(const char *group)
150 struct stat _yp_statp;
156 if (group == NULL || !strlen(group))
159 if (grouphead.gr == NULL ||
160 strcmp(group, grouphead.grname)) {
163 /* Presumed guilty until proven innocent. */
166 * If /etc/netgroup doesn't exist or is empty,
167 * use NIS exclusively.
169 if (((stat(_PATH_NETGROUP, &_yp_statp) < 0) &&
170 errno == ENOENT) || _yp_statp.st_size == 0)
171 _use_only_yp = _netgr_yp_enabled = 1;
172 if ((netf = fopen(_PATH_NETGROUP,"r")) != NULL ||_use_only_yp){
174 * Icky: grab the first character of the netgroup file
175 * and turn on NIS if it's a '+'. rewind the stream
176 * afterwards so we don't goof up read_for_group() later.
179 fscanf(netf, "%c", &_yp_plus);
182 _use_only_yp = _netgr_yp_enabled = 1;
185 * If we were called specifically for an innetgr()
186 * lookup and we're in NIS-only mode, short-circuit
187 * parse_netgroup() and cut directly to the chase.
189 if (_use_only_yp && _yp_innetgr) {
196 if (netf = fopen(_PATH_NETGROUP, "r")) {
198 if (parse_netgrp(group))
201 grouphead.grname = (char *)
202 malloc(strlen(group) + 1);
203 strcpy(grouphead.grname, group);
209 nextgrp = grouphead.gr;
213 * Get the next netgroup off the list.
216 getnetgrent(char **hostp, char **userp, char **domp)
223 *hostp = nextgrp->ng_str[NG_HOST];
224 *userp = nextgrp->ng_str[NG_USER];
225 *domp = nextgrp->ng_str[NG_DOM];
226 nextgrp = nextgrp->ng_next;
233 * endnetgrent() - cleanup
238 struct linelist *lp, *olp;
239 struct netgrp *gp, *ogp;
245 free(olp->l_groupname);
250 if (grouphead.grname) {
251 free(grouphead.grname);
252 grouphead.grname = NULL;
258 if (ogp->ng_str[NG_HOST])
259 free(ogp->ng_str[NG_HOST]);
260 if (ogp->ng_str[NG_USER])
261 free(ogp->ng_str[NG_USER]);
262 if (ogp->ng_str[NG_DOM])
263 free(ogp->ng_str[NG_DOM]);
269 _netgr_yp_enabled = 0;
275 _listmatch(const char *list, const char *group, int len)
277 const char *ptr = list;
279 int glen = strlen(group);
281 /* skip possible leading whitespace */
282 while(isspace((unsigned char)*ptr))
285 while (ptr < list + len) {
287 while(*ptr != ',' && *ptr != '\0' && !isspace((unsigned char)*ptr))
289 if (strncmp(cptr, group, glen) == 0 && glen == (ptr - cptr))
291 while(*ptr == ',' || isspace((unsigned char)*ptr))
299 _revnetgr_lookup(char *lookupdom, char *map, const char *str,
300 const char *dom, const char *group)
303 char key[MAXHOSTNAMELEN];
307 for (rot = 0; ; rot++) {
309 case(0): snprintf(key, MAXHOSTNAMELEN, "%s.%s",
310 str, dom?dom:lookupdom);
312 case(1): snprintf(key, MAXHOSTNAMELEN, "%s.*",
315 case(2): snprintf(key, MAXHOSTNAMELEN, "*.%s",
318 case(3): snprintf(key, MAXHOSTNAMELEN, "*.*");
322 y = yp_match(lookupdom, map, key, strlen(key), &result,
325 rv = _listmatch(result, group, resultlen);
328 } else if (y != YPERR_KEY) {
330 * If we get an error other than 'no
331 * such key in map' then something is
332 * wrong and we should stop the search.
341 * Search for a match in a netgroup.
344 innetgr(const char *group, const char *host, const char *user, const char *dom)
346 char *hst, *usr, *dm;
349 if (group == NULL || !strlen(group))
359 * If we're in NIS-only mode, do the search using
360 * NIS 'reverse netgroup' lookups.
362 * What happens with 'reverse netgroup' lookups:
364 * 1) try 'reverse netgroup' lookup
365 * 1.a) if host is specified and user is null:
366 * look in netgroup.byhost
367 * (try host.domain, host.*, *.domain or *.*)
368 * if found, return yes
369 * 1.b) if user is specified and host is null:
370 * look in netgroup.byuser
371 * (try host.domain, host.*, *.domain or *.*)
372 * if found, return yes
373 * 1.c) if both host and user are specified,
374 * don't do 'reverse netgroup' lookup. It won't work.
375 * 1.d) if neither host ane user are specified (why?!?)
376 * don't do 'reverse netgroup' lookup either.
377 * 2) if domain is specified and 'reverse lookup' is done:
378 * 'reverse lookup' was authoritative. bye bye.
379 * 3) otherwise, too bad, try it the slow way.
381 if (_use_only_yp && (host == NULL) != (user == NULL)) {
383 if(yp_get_default_domain(&_netgr_yp_domain))
385 ret = _revnetgr_lookup(_netgr_yp_domain,
386 host?"netgroup.byhost":"netgroup.byuser",
387 host?host:user, dom, group);
390 else if (ret == 0 && dom != NULL)
397 while (getnetgrent(&hst, &usr, &dm))
398 if ((host == NULL || hst == NULL || !strcmp(host, hst)) &&
399 (user == NULL || usr == NULL || !strcmp(user, usr)) &&
400 ( dom == NULL || dm == NULL || !strcmp(dom, dm))) {
409 * Parse the netgroup file setting up the linked lists.
412 parse_netgrp(const char *group)
421 struct linelist *lp = linehead;
424 * First, see if the line has already been read in.
427 if (!strcmp(group, lp->l_groupname))
432 (lp = read_for_group(group)) == NULL)
437 * This error message is largely superflous since the
438 * code handles the error condition successfully, and
439 * spewing it out from inside libc can actually hose
442 fprintf(stderr, "Cycle in netgroup %s\n", lp->l_groupname);
448 /* Watch for null pointer dereferences, dammit! */
449 while (pos != NULL && *pos != '\0') {
451 grp = (struct netgrp *)malloc(sizeof (struct netgrp));
452 bzero((char *)grp, sizeof (struct netgrp));
453 grp->ng_next = grouphead.gr;
456 gpos = strsep(&pos, ")");
460 for (strpos = 0; strpos < 3; strpos++) {
461 if ((spos = strsep(&gpos, ","))) {
465 while (*spos == ' ' || *spos == '\t')
467 if ((epos = strpbrk(spos, " \t"))) {
473 grp->ng_str[strpos] = (char *)
475 bcopy(spos, grp->ng_str[strpos],
480 * All other systems I've tested
481 * return NULL for empty netgroup
482 * fields. It's up to user programs
483 * to handle the NULLs appropriately.
485 grp->ng_str[strpos] = NULL;
490 * Note: on other platforms, malformed netgroup
491 * entries are not normally flagged. While we
492 * can catch bad entries and report them, we should
493 * stay silent by default for compatibility's sake.
496 fprintf(stderr, "Bad entry (%s%s%s%s%s) in netgroup \"%s\"\n",
497 grp->ng_str[NG_HOST] == NULL ? "" : grp->ng_str[NG_HOST],
498 grp->ng_str[NG_USER] == NULL ? "" : ",",
499 grp->ng_str[NG_USER] == NULL ? "" : grp->ng_str[NG_USER],
500 grp->ng_str[NG_DOM] == NULL ? "" : ",",
501 grp->ng_str[NG_DOM] == NULL ? "" : grp->ng_str[NG_DOM],
505 spos = strsep(&pos, ", \t");
506 if (parse_netgrp(spos))
511 while (*pos == ' ' || *pos == ',' || *pos == '\t')
518 * Read the netgroup file and save lines until the line for the netgroup
519 * is found. Return 1 if eof is encountered.
521 static struct linelist *
522 read_for_group(const char *group)
524 char *pos, *spos, *linep = NULL, *olinep = NULL;
528 char line[LINSIZ + 2];
533 while (_netgr_yp_enabled || fgets(line, LINSIZ, netf) != NULL) {
534 if (_netgr_yp_enabled) {
535 if(!_netgr_yp_domain)
536 if(yp_get_default_domain(&_netgr_yp_domain))
538 if (yp_match(_netgr_yp_domain, "netgroup", group,
539 strlen(group), &result, &resultlen)) {
544 _netgr_yp_enabled = 0;
548 snprintf(line, LINSIZ, "%s %s", group, result);
552 while (fgets(line, LINSIZ, netf) != NULL) {
557 _netgr_yp_enabled = 1;
563 while (*pos == ' ' || *pos == '\t')
566 while (*pos != ' ' && *pos != '\t' && *pos != '\n' &&
570 while (*pos == ' ' || *pos == '\t')
572 if (*pos != '\n' && *pos != '\0') {
573 lp = (struct linelist *)malloc(sizeof (*lp));
575 lp->l_groupname = (char *)malloc(len + 1);
576 bcopy(spos, lp->l_groupname, len);
577 *(lp->l_groupname + len) = '\0';
582 * Loop around handling line continuations.
585 if (*(pos + len - 1) == '\n')
587 if (*(pos + len - 1) == '\\') {
593 linep = (char *)malloc(olen + len + 1);
595 bcopy(olinep, linep, olen);
598 bcopy(pos, linep + olen, len);
600 *(linep + olen) = '\0';
604 if (fgets(line, LINSIZ, netf)) {
612 lp->l_next = linehead;
616 * If this is the one we wanted, we are done.
618 if (!strcmp(lp->l_groupname, group))
624 * Yucky. The recursive nature of this whole mess might require
625 * us to make more than one pass through the netgroup file.
626 * This might be best left outside the #ifdef YP, but YP is
627 * defined by default anyway, so I'll leave it like this
628 * until I know better.