sys/gettimeofday.c

   1 /*
   2  * Copyright (c) 2003-2005 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 /*
  24  * Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved
  25  *
  26  *      File:   libc/sys/gettimeofday.c
  27  */
  28
  29 #include <time.h>
  30 #include <tzfile.h>
  31 #include <sys/time.h>
  32 #include <errno.h>
  33 #include <unistd.h>
  34
  35 #define __APPLE_API_PRIVATE
  36 #include <machine/cpu_capabilities.h>
  37 #undef  __APPLE_API_PRIVATE
  38
  39 extern int __gettimeofday(struct timeval *, struct timezone *);
  40 extern int __commpage_gettimeofday(struct timeval *);
  41
  42 int gettimeofday (struct timeval *tp, void *vtzp)
  43 {
  44         static int validtz = 0;
  45         static struct timezone cached_tz = {0};
  46         struct timezone *tzp = (struct timezone *)vtzp;
  47         struct timeval atv;
  48
  49         if (tp == NULL) {
  50             if (tzp == NULL)
  51                 return  (0);
  52             tp = &atv;
  53         }
  54
  55         if (__commpage_gettimeofday(tp)) {              /* first try commpage */
  56                 if (__gettimeofday(tp, NULL) < 0) {     /* if it fails, use syscall */
  57                         return (-1);
  58                 }
  59         }
  60
  61         if (tzp) {
  62             if (validtz == 0)  {
  63                 struct tm *localtm = localtime ((time_t *)&tp->tv_sec);
  64                 cached_tz.tz_dsttime = localtm->tm_isdst;
  65                 cached_tz.tz_minuteswest =
  66                     (-localtm->tm_gmtoff / SECSPERMIN) +
  67                     (localtm->tm_isdst * MINSPERHOUR);
  68                 validtz = 1;
  69             }
  70             tzp->tz_dsttime = cached_tz.tz_dsttime;
  71             tzp->tz_minuteswest = cached_tz.tz_minuteswest;
  72         }
  73         return (0);
  74 }