lib/libc/gen/getgrouplist.c

   1 /*
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * @(#)getgrouplist.c   8.2 (Berkeley) 12/8/94
  34  * $DragonFly: src/lib/libc/gen/getgrouplist.c,v 1.6 2005/04/27 14:37:43 joerg Exp $
  35  */
  36
  37 /*
  38  * get credential
  39  */
  40 #include <grp.h>
  41 #include <string.h>
  42 #include <unistd.h>
  43
  44 int
  45 getgrouplist(const char *uname, gid_t agroup, gid_t *groups, int *grpcnt)
  46 {
  47         struct group *grp;
  48         int i, ngroups;
  49         int ret, maxgroups;
  50
  51         ret = 0;
  52         ngroups = 0;
  53         maxgroups = *grpcnt;
  54         /*
  55          * When installing primary group, duplicate it;
  56          * the first element of groups is the effective gid
  57          * and will be overwritten when a setgid file is executed.
  58          */
  59         groups[ngroups++] = agroup;
  60         if (maxgroups > 1)
  61                 groups[ngroups++] = agroup;
  62         /*
  63          * Scan the group file to find additional groups.
  64          */
  65         setgrent();
  66         while ((grp = getgrent()) != NULL) {
  67                 for (i = 0; i < ngroups; i++) {
  68                         if (grp->gr_gid == groups[i])
  69                                 goto skip;
  70                 }
  71                 for (i = 0; grp->gr_mem[i]; i++) {
  72                         if (!strcmp(grp->gr_mem[i], uname)) {
  73                                 if (ngroups >= maxgroups) {
  74                                         ret = -1;
  75                                         break;
  76                                 }
  77                                 groups[ngroups++] = grp->gr_gid;
  78                                 break;
  79                         }
  80                 }
  81 skip:
  82                 ;
  83         }
  84         endgrent();
  85         *grpcnt = ngroups;
  86         return (ret);
  87 }