libsyscall/wrappers/gethostuuid.c

   1 /*
   2  * Copyright (c) 2013 Apple 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 #include <sys/types.h>
  25 #include <sys/time.h>
  26 #include <sys/errno.h>
  27 #include <strings.h>
  28 #include <Availability.h>
  29
  30 #include "gethostuuid_private.h"
  31
  32 extern int __gethostuuid(uuid_t, const struct timespec *, int);
  33
  34 static volatile int (*_gethostuuid_callback)(uuid_t) = (void *)0;
  35
  36 int
  37 gethostuuid(uuid_t uuid, const struct timespec *timeout)
  38 {
  39         int result;
  40
  41         result = __gethostuuid(uuid, timeout, 0);
  42         if ((result == -1) && (errno == EPERM)) {
  43                 if (_gethostuuid_callback) {
  44                         result = _gethostuuid_callback(uuid);
  45                 } else {
  46                         /* no fallback, return -1/EPERM */
  47                         memset(uuid, 0x00, sizeof(*uuid));
  48                 }
  49         }
  50
  51         return result;
  52 }
  53
  54 /* SPI to call gethostuuid syscall directly, without fallback */
  55 int
  56 _getprivatesystemidentifier(uuid_t uuid, const struct timespec *timeout)
  57 {
  58         return __gethostuuid(uuid, timeout, 1);
  59 }
  60
  61 int
  62 _register_gethostuuid_callback(int (*new_callback)(uuid_t))
  63 {
  64
  65         if (__sync_bool_compare_and_swap((void **)&_gethostuuid_callback, (void *)0, (void *)new_callback)) {
  66                 return 0;
  67         } else {
  68                 return EINVAL;
  69         }
  70 }