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getgrouplist.c revision 1.16 
      1 /*	$NetBSD: getgrouplist.c,v 1.16 2003/02/16 01:22:44 elric Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1991, 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)getgrouplist.c	8.2 (Berkeley) 12/8/94";
     40 #else
     41 __RCSID("$NetBSD: getgrouplist.c,v 1.16 2003/02/16 01:22:44 elric Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 /*
     46  * get credential
     47  */
     48 #include "namespace.h"
     49 #include <sys/param.h>
     50 
     51 #include <assert.h>
     52 #include <grp.h>
     53 #include <string.h>
     54 #include <unistd.h>
     55 
     56 #ifdef __weak_alias
     57 __weak_alias(getgrouplist,_getgrouplist)
     58 #endif
     59 
     60 /*
     61  * _getgrent_user() is a libc-private function defined in getgrent.c which
     62  * use because certain name service types such as Hesiod lookup grouplists
     63  * by username rather than just iterating over the list of groups.
     64  */
     65 struct group *_getgrent_user(const char *);
     66 
     67 int
     68 getgrouplist(uname, agroup, groups, grpcnt)
     69 	const char *uname;
     70 	gid_t agroup;
     71 	gid_t *groups;
     72 	int *grpcnt;
     73 {
     74 	struct group *grp;
     75 	int i, ngroups;
     76 	int ret, maxgroups;
     77 
     78 	_DIAGASSERT(uname != NULL);
     79 	_DIAGASSERT(groups != NULL);
     80 	_DIAGASSERT(grpcnt != NULL);
     81 
     82 	ret = 0;
     83 	ngroups = 0;
     84 	maxgroups = *grpcnt;
     85 
     86 	/*
     87 	 * install primary group
     88 	 */
     89 	if (ngroups < maxgroups)
     90 		groups[ngroups] = agroup;
     91 	else
     92 		ret = -1;
     93 	ngroups++;
     94 
     95 	/*
     96 	 * Scan the group file to find additional groups.
     97 	 */
     98 	setgrent();
     99  nextgroup:
    100 	while ((grp = _getgrent_user(uname)) != NULL) {
    101 		if (grp->gr_gid == agroup)
    102 			continue;
    103 		for (i = 0; i < MIN(ngroups, maxgroups); i++) {
    104 			if (grp->gr_gid == groups[i])
    105 				goto nextgroup;
    106 		}
    107 		if (ngroups < maxgroups)
    108 			groups[ngroups] = grp->gr_gid;
    109 		else
    110 			ret = -1;
    111 		ngroups++;
    112 	}
    113 	endgrent();
    114 	*grpcnt = ngroups;
    115 	return (ret);
    116 }
    117