getgrent.c revision 1.8 
1/*	$NetBSD: getgrent.c,v 1.8 2003/10/13 15:36:33 agc Exp $	*/
2
3/*
4 * Copyright (c) 1989, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32/*
33 * Portions Copyright (c) 1994, Jason Downs. All Rights Reserved.
34 *
35 * Redistribution and use in source and binary forms, with or without
36 * modification, are permitted provided that the following conditions
37 * are met:
38 * 1. Redistributions of source code must retain the above copyright
39 *    notice, this list of conditions and the following disclaimer.
40 * 2. Redistributions in binary form must reproduce the above copyright
41 *    notice, this list of conditions and the following disclaimer in the
42 *    documentation and/or other materials provided with the distribution.
43 *
44 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS
45 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
46 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
47 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT,
48 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
49 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
50 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
51 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
52 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
53 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
54 * SUCH DAMAGE.
55 */
56
57/*
58 * Copied from:  lib/libc/gen/getgrent.c
59 *     NetBSD: getgrent.c,v 1.46 2003/02/17 00:11:54 simonb Exp
60 * and then gutted, leaving only /etc/group support.
61 */
62
63#include <sys/cdefs.h>
64
65#ifdef __weak_alias
66#define endgrent		_endgrent
67#define getgrent		_getgrent
68#define getgrgid		_getgrgid
69#define getgrnam		_getgrnam
70#define setgrent		_setgrent
71#define setgroupent		_setgroupent
72
73__weak_alias(endgrent,_endgrent)
74__weak_alias(getgrent,_getgrent)
75__weak_alias(getgrgid,_getgrgid)
76__weak_alias(getgrnam,_getgrnam)
77__weak_alias(setgrent,_setgrent)
78__weak_alias(setgroupent,_setgroupent)
79#endif
80
81#include <sys/types.h>
82
83#include <grp.h>
84#include <limits.h>
85#include <stdio.h>
86#include <stdlib.h>
87#include <string.h>
88
89struct group *_getgrent_user(const char *);
90
91static FILE		*_gr_fp;
92static struct group	_gr_group;
93static int		_gr_stayopen;
94static int		_gr_filesdone;
95
96static int grscan(int, gid_t, const char *, const char *);
97static int grstart(void);
98static int grmatchline(int, gid_t, const char *, const char *);
99
100#define	MAXGRP		200
101#define	MAXLINELENGTH	1024
102
103static __aconst char	*members[MAXGRP];
104static char		grline[MAXLINELENGTH];
105
106struct group *
107getgrent(void)
108{
109
110	if ((!_gr_fp && !grstart()) || !grscan(0, 0, NULL, NULL))
111 		return (NULL);
112	return &_gr_group;
113}
114
115/*
116 * _getgrent_user() is designed only to be called by getgrouplist(3) and
117 * hence makes no guarantees about filling the entire structure that it
118 * returns.  It may only fill in the group name and gid fields.
119 */
120
121struct group *
122_getgrent_user(const char *user)
123{
124
125	if ((!_gr_fp && !grstart()) || !grscan(0, 0, NULL, user))
126 		return (NULL);
127	return &_gr_group;
128}
129
130struct group *
131getgrnam(const char *name)
132{
133	int rval;
134
135	if (!grstart())
136		return NULL;
137	rval = grscan(1, 0, name, NULL);
138	if (!_gr_stayopen)
139		endgrent();
140	return (rval) ? &_gr_group : NULL;
141}
142
143struct group *
144getgrgid(gid_t gid)
145{
146	int rval;
147
148	if (!grstart())
149		return NULL;
150	rval = grscan(1, gid, NULL, NULL);
151	if (!_gr_stayopen)
152		endgrent();
153	return (rval) ? &_gr_group : NULL;
154}
155
156static int
157grstart(void)
158{
159
160	_gr_filesdone = 0;
161	if (_gr_fp) {
162		rewind(_gr_fp);
163		return 1;
164	}
165	return (_gr_fp = fopen(_PATH_GROUP, "r")) ? 1 : 0;
166}
167
168void
169setgrent(void)
170{
171
172	(void) setgroupent(0);
173}
174
175int
176setgroupent(int stayopen)
177{
178
179	if (!grstart())
180		return 0;
181	_gr_stayopen = stayopen;
182	return 1;
183}
184
185void
186endgrent(void)
187{
188
189	_gr_filesdone = 0;
190	if (_gr_fp) {
191		(void)fclose(_gr_fp);
192		_gr_fp = NULL;
193	}
194}
195
196static int
197grscan(int search, gid_t gid, const char *name, const char *user)
198{
199
200	if (_gr_filesdone)
201		return 0;
202	for (;;) {
203		if (!fgets(grline, sizeof(grline), _gr_fp)) {
204			if (!search)
205				_gr_filesdone = 1;
206			return 0;
207		}
208		/* skip lines that are too big */
209		if (!strchr(grline, '\n')) {
210			int ch;
211
212			while ((ch = getc(_gr_fp)) != '\n' && ch != EOF)
213				;
214			continue;
215		}
216		if (grmatchline(search, gid, name, user))
217			return 1;
218	}
219	/* NOTREACHED */
220}
221
222static int
223grmatchline(int search, gid_t gid, const char *name, const char *user)
224{
225	unsigned long	id;
226	__aconst char	**m;
227	char		*cp, *bp, *ep;
228
229	/* name may be NULL if search is nonzero */
230
231	bp = grline;
232	_gr_group.gr_name = strsep(&bp, ":\n");
233	if (search && name && strcmp(_gr_group.gr_name, name))
234		return 0;
235	_gr_group.gr_passwd = strsep(&bp, ":\n");
236	if (!(cp = strsep(&bp, ":\n")))
237		return 0;
238	id = strtoul(cp, &ep, 10);
239	if (id > GID_MAX || *ep != '\0')
240		return 0;
241	_gr_group.gr_gid = (gid_t)id;
242	if (search && name == NULL && _gr_group.gr_gid != gid)
243		return 0;
244	cp = NULL;
245	if (bp == NULL)
246		return 0;
247	for (_gr_group.gr_mem = m = members;; bp++) {
248		if (m == &members[MAXGRP - 1])
249			break;
250		if (*bp == ',') {
251			if (cp) {
252				*bp = '\0';
253				*m++ = cp;
254				cp = NULL;
255			}
256		} else if (*bp == '\0' || *bp == '\n' || *bp == ' ') {
257			if (cp) {
258				*bp = '\0';
259				*m++ = cp;
260			}
261			break;
262		} else if (cp == NULL)
263			cp = bp;
264	}
265	*m = NULL;
266	if (user) {
267		for (m = members; *m; m++)
268			if (!strcmp(user, *m))
269				return 1;
270		return 0;
271	}
272	return 1;
273}
274