sys/fchmod.c

   1 /*
   2  * Copyright (c) 2005 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 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <errno.h>
  26
  27 extern int __fchmod(int fd, mode_t mode);
  28
  29 /*
  30  * fchmod stub, ignore S_ISUID and/or S_ISGID on EPERM,
  31  * mandated for conformance.
  32  *
  33  * This is for UNIX03 only.
  34  */
  35 int
  36 fchmod(int fd, mode_t mode)
  37 {
  38         int res = __fchmod(fd, mode);
  39
  40         if (res >= 0 || errno != EPERM || (mode & (S_ISUID | S_ISGID)) == 0)
  41                 return res;
  42         if (mode & S_ISGID) {
  43                 res = __fchmod(fd, mode ^ S_ISGID);
  44                 if (res >= 0 || errno != EPERM)
  45                         return res;
  46         }
  47         if (mode & S_ISUID) {
  48                 res = __fchmod(fd, mode ^ S_ISUID);
  49                 if (res >= 0 || errno != EPERM)
  50                         return res;
  51         }
  52         if (mode & (S_ISUID | S_ISGID) == (S_ISUID | S_ISGID))
  53                 res = __fchmod(fd, mode ^ (S_ISUID | S_ISGID));
  54         return res;
  55 }