Libc-391.5.22.tar.gz

[apple/libc.git] / sys / gettimeofday.c

/*
 * Copyright (c) 2003-2005 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved
 *
 * 	File:	libc/sys/gettimeofday.c
 */

#include <time.h>
#include <tzfile.h>
#include <sys/time.h>
#include <errno.h>
#include <sys/syscall.h>
#include <unistd.h>

#define	__APPLE_API_PRIVATE
#include <machine/cpu_capabilities.h>
#undef	__APPLE_API_PRIVATE


int gettimeofday (struct timeval *tp, struct timezone *tzp)
{
		extern int __gettimeofday(struct timeval *, struct timezone *);
		extern int __commpage_gettimeofday(struct timeval *);
        static int validtz = 0;
        static struct timezone cached_tz = {0};
        struct timeval atv;
  
        if (tp == NULL) {
            if (tzp == NULL)
                return	(0);
            tp = &atv;
        }

		if (__commpage_gettimeofday(tp)) {		/* first try commpage */
			if (__gettimeofday(tp, tzp) < 0) {	/* if it fails, use syscall */
				return (-1);
			}
		}

        if (tzp) {
            if (validtz == 0)  {
                struct tm *localtm = localtime ((time_t *)&tp->tv_sec);
                cached_tz.tz_dsttime = localtm->tm_isdst;
                cached_tz.tz_minuteswest =
                    (-localtm->tm_gmtoff / SECSPERMIN) +
                    (localtm->tm_isdst * MINSPERHOUR);
                validtz = 1;
            }
            tzp->tz_dsttime = cached_tz.tz_dsttime;
            tzp->tz_minuteswest = cached_tz.tz_minuteswest;
        }
        return (0);
}