compat-43/setregid.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * Copyright (c) 1983, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  *
  27  * Redistribution and use in source and binary forms, with or without
  28  * modification, are permitted provided that the following conditions
  29  * are met:
  30  * 1. Redistributions of source code must retain the above copyright
  31  *    notice, this list of conditions and the following disclaimer.
  32  * 2. Redistributions in binary form must reproduce the above copyright
  33  *    notice, this list of conditions and the following disclaimer in the
  34  *    documentation and/or other materials provided with the distribution.
  35  * 3. All advertising materials mentioning features or use of this software
  36  *    must display the following acknowledgement:
  37  *      This product includes software developed by the University of
  38  *      California, Berkeley and its contributors.
  39  * 4. Neither the name of the University nor the names of its contributors
  40  *    may be used to endorse or promote products derived from this software
  41  *    without specific prior written permission.
  42  *
  43  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  44  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  45  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  46  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  47  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  48  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  49  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  50  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  51  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  52  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  53  * SUCH DAMAGE.
  54  */
  55
  56 #include <sys/types.h>
  57 #include <unistd.h>
  58 #include <errno.h>
  59
  60 int
  61 setregid(rgid, egid)
  62         gid_t rgid, egid;
  63 {
  64         static gid_t savedgid = -1;
  65
  66         if (savedgid == -1)
  67                 savedgid = getegid();
  68         /*
  69          * we assume that the intent here is to be able to
  70          * get back rgid priviledge. So we make sure that
  71          * we will be able to do so, but do not actually
  72          * set the rgid.
  73          */
  74         if (rgid != -1 && rgid != getgid() && rgid != savedgid) {
  75                 errno = EPERM;
  76                 return (-1);
  77         }
  78         if (egid != -1 && setegid(egid) < 0)
  79                 return (-1);
  80         return (0);
  81 }