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getgrouplist.c revision 1.17 
      1 /*	$NetBSD: getgrouplist.c,v 1.17 2003/08/07 16:42:49 agc 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. 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 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 #if 0
     35 static char sccsid[] = "@(#)getgrouplist.c	8.2 (Berkeley) 12/8/94";
     36 #else
     37 __RCSID("$NetBSD: getgrouplist.c,v 1.17 2003/08/07 16:42:49 agc Exp $");
     38 #endif
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 /*
     42  * get credential
     43  */
     44 #include "namespace.h"
     45 #include <sys/param.h>
     46 
     47 #include <assert.h>
     48 #include <grp.h>
     49 #include <string.h>
     50 #include <unistd.h>
     51 
     52 #ifdef __weak_alias
     53 __weak_alias(getgrouplist,_getgrouplist)
     54 #endif
     55 
     56 /*
     57  * _getgrent_user() is a libc-private function defined in getgrent.c which
     58  * use because certain name service types such as Hesiod lookup grouplists
     59  * by username rather than just iterating over the list of groups.
     60  */
     61 struct group *_getgrent_user(const char *);
     62 
     63 int
     64 getgrouplist(uname, agroup, groups, grpcnt)
     65 	const char *uname;
     66 	gid_t agroup;
     67 	gid_t *groups;
     68 	int *grpcnt;
     69 {
     70 	struct group *grp;
     71 	int i, ngroups;
     72 	int ret, maxgroups;
     73 
     74 	_DIAGASSERT(uname != NULL);
     75 	_DIAGASSERT(groups != NULL);
     76 	_DIAGASSERT(grpcnt != NULL);
     77 
     78 	ret = 0;
     79 	ngroups = 0;
     80 	maxgroups = *grpcnt;
     81 
     82 	/*
     83 	 * install primary group
     84 	 */
     85 	if (ngroups < maxgroups)
     86 		groups[ngroups] = agroup;
     87 	else
     88 		ret = -1;
     89 	ngroups++;
     90 
     91 	/*
     92 	 * Scan the group file to find additional groups.
     93 	 */
     94 	setgrent();
     95  nextgroup:
     96 	while ((grp = _getgrent_user(uname)) != NULL) {
     97 		if (grp->gr_gid == agroup)
     98 			continue;
     99 		for (i = 0; i < MIN(ngroups, maxgroups); i++) {
    100 			if (grp->gr_gid == groups[i])
    101 				goto nextgroup;
    102 		}
    103 		if (ngroups < maxgroups)
    104 			groups[ngroups] = grp->gr_gid;
    105 		else
    106 			ret = -1;
    107 		ngroups++;
    108 	}
    109 	endgrent();
    110 	*grpcnt = ngroups;
    111 	return (ret);
    112 }
    113