usr/src/lib/libc/port/gen/initgroups.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #pragma weak _initgroups = initgroups
  33
  34 #include "lint.h"
  35 #include <stdlib.h>
  36 #include <errno.h>
  37 #include <grp.h>
  38 #include <sys/types.h>
  39 #include <sys/param.h>
  40 #include <unistd.h>
  41
  42 /* Private interface to the groups code in getgrnam.c */
  43 extern int _getgroupsbymember(const char *, gid_t[], int, int);
  44
  45 int
  46 initgroups(const char *uname, gid_t agroup)
  47 {
  48         gid_t *groups;
  49         long ngroups_max;
  50         int ngroups;
  51         int errsave, retsave;
  52
  53         if ((ngroups_max = sysconf(_SC_NGROUPS_MAX)) < 0) {
  54                 /* ==== Hope sysconf() set errno to something sensible */
  55                 return (-1);
  56         }
  57         /*
  58          * ngroups_max is the maximum number of supplemental groups per
  59          * process. if no supplemental groups are allowed, we're done.
  60          */
  61         if (ngroups_max == 0)
  62                 return (0);
  63
  64         if ((groups = (gid_t *)calloc(ngroups_max, sizeof (gid_t))) == 0) {
  65                 errno = ENOMEM;
  66                 return (-1);
  67         }
  68         groups[0] = agroup;
  69
  70         ngroups = _getgroupsbymember(uname, groups, (int)ngroups_max,
  71             (agroup <= MAXUID) ? 1 : 0);
  72         if (ngroups < 0) {
  73                 /* XXX -- man page does not define a value for errno in */
  74                 /* this case.  Should be looked into sometime.  */
  75                 free(groups);
  76                 return (-1);
  77         }
  78
  79         retsave = setgroups(ngroups, groups);
  80         errsave = errno;
  81
  82         free(groups);
  83
  84         errno = errsave;
  85         return (retsave);
  86 }