minix/lib/libc/sys/ntp_adjtime.c

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/* $NetBSD: ntp_adjtime.c,v 1.13 2012/03/20 16:26:12 matt Exp $ */
/*
* Copyright (c) 2001 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Emmanuel Dreyfus.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: ntp_adjtime.c,v 1.13 2012/03/20 16:26:12 matt Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/types.h>
#include <sys/time.h>
#include <sys/timex.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <sys/clockctl.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <string.h>
#include <unistd.h>
#ifdef __weak_alias
__weak_alias(ntp_adjtime,_ntp_adjtime)
#endif
#if defined(__minix) && !defined(O_CLOEXEC)
#define O_CLOEXEC 0
#endif
extern int __clockctl_fd;
int __ntp_adjtime(struct timex *);
int
ntp_adjtime(struct timex *tp)
{
struct clockctl_ntp_adjtime args;
int error;
int rv;
/*
* we always attempt to use the syscall unless we had to
* use the clockctl device before
*
* ntp_adjtime() is callable for mortals if tp->modes == 0 !
*/
if (__clockctl_fd == -1) {
rv = __ntp_adjtime(tp);
/*
* if we fail with EPERM we try the clockctl device
*/
if (rv != -1 || errno != EPERM)
return rv;
/*
* If this fails, it means that we are not root
* and we cannot open clockctl. This is a true
* failure.
*/
__clockctl_fd = open(_PATH_CLOCKCTL, O_WRONLY | O_CLOEXEC, 0);
if (__clockctl_fd == -1) {
/* original error was EPERM - don't leak open errors */
errno = EPERM;
return -1;
}
}
/*
* If __clockctl_fd >=0, clockctl has already been open
* and used, so we carry on using it.
*/
args.tp = tp;
error = ioctl(__clockctl_fd, CLOCKCTL_NTP_ADJTIME, &args);
/*
* There is no way to get retval set through ioctl(), hence we
* have to handle it here, using args.retval
*/
if (error == 0) {
rv = (int)args.retval;
return rv;
}
return error;
}