gen/OSSystemInfo.c

   1 /*
   2  * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25
  26 #include <sys/types.h>
  27 #include <sys/sysctl.h>
  28 #include <stdbool.h>
  29
  30 static int      osi_oid[2] = {-1, 0};
  31
  32 bool
  33 OSSystemInfo(int selector, unsigned long long *resultp)
  34 {
  35         int oid[3];
  36         size_t size;
  37
  38         /*
  39          * Check cached OID, look it up if we haven't already.
  40          *
  41          * NB. Whilst this isn't strictly thread safe, since the
  42          *     result as written by any thread will be the same
  43          *     there is no actual risk of corruption.
  44          */
  45         if (osi_oid[0] == -1) {
  46                 size = 2;
  47                 if (sysctlnametomib("hw.systeminfo", &osi_oid, &size) ||
  48                     (size != 2))
  49                         return(false);
  50         }
  51
  52         /* build OID */
  53         oid[0] = osi_oid[0];
  54         oid[1] = osi_oid[1];
  55         oid[2] = selector;
  56
  57         /* make the call */
  58         size = sizeof(*resultp);
  59         if (sysctl(oid, 3, resultp, &size, NULL, 0) ||
  60             (size != sizeof(*resultp)))
  61                 return(false);
  62
  63         return(true);
  64 }
  65