gen/OSSystemInfo.c

   1 /*
   2  * Copyright (c) 2003 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 #include <sys/types.h>
  25 #include <sys/sysctl.h>
  26 #include <stdbool.h>
  27
  28 static int      osi_oid[2] = {-1, 0};
  29
  30 bool
  31 OSSystemInfo(int selector, unsigned long long *resultp)
  32 {
  33         int oid[3];
  34         size_t size;
  35
  36         /*
  37          * Check cached OID, look it up if we haven't already.
  38          *
  39          * NB. Whilst this isn't strictly thread safe, since the
  40          *     result as written by any thread will be the same
  41          *     there is no actual risk of corruption.
  42          */
  43         if (osi_oid[0] == -1) {
  44                 size = 2;
  45                 if (sysctlnametomib("hw.systeminfo", &osi_oid, &size) ||
  46                     (size != 2))
  47                         return(false);
  48         }
  49
  50         /* build OID */
  51         oid[0] = osi_oid[0];
  52         oid[1] = osi_oid[1];
  53         oid[2] = selector;
  54
  55         /* make the call */
  56         size = sizeof(*resultp);
  57         if (sysctl(oid, 3, resultp, &size, NULL, 0) ||
  58             (size != sizeof(*resultp)))
  59                 return(false);
  60
  61         return(true);
  62 }
  63