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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <limits.h>
#include "dispadmin.h"
/*
* Utility functions for dispadmin command.
*/
void
fatalerr(const char *format, ...)
{
va_list ap;
(void) va_start(ap, format);
(void) vfprintf(stderr, format, ap);
va_end(ap);
exit(1);
}
/*
* hrtconvert() returns the interval specified by htp as a single
* value in resolution htp->hrt_res. Returns -1 on overflow.
*/
long
hrtconvert(hrtimer_t *htp)
{
long sum;
long product;
product = htp->hrt_secs * htp->hrt_res;
if (product / htp->hrt_res == htp->hrt_secs) {
sum = product + htp->hrt_rem;
if (sum - htp->hrt_rem == product) {
return (sum);
}
}
return (-1);
}
/*
* The following routine was removed from libc (libc/port/gen/hrtnewres.c).
* It has also been added to priocntl, so if you fix it here, you should
* also probably fix it there. In the long term, this should be recoded to
* not be hrt'ish.
*/
/*
* Convert interval expressed in htp->hrt_res to new_res.
*
* Calculate: (interval * new_res) / htp->hrt_res rounding off as
* specified by round.
*
* Note: All args are assumed to be positive. If
* the last divide results in something bigger than
* a long, then -1 is returned instead.
*/
int
_hrtnewres(hrtimer_t *htp, ulong_t new_res, long round)
{
long interval;
longlong_t dint;
longlong_t dto_res;
longlong_t drem;
longlong_t dfrom_res;
longlong_t prod;
longlong_t quot;
long numerator;
long result;
ulong_t modulus;
ulong_t twomodulus;
long temp;
if (htp->hrt_res == 0 || new_res == 0 ||
new_res > NANOSEC || htp->hrt_rem < 0)
return (-1);
if (htp->hrt_rem >= htp->hrt_res) {
htp->hrt_secs += htp->hrt_rem / htp->hrt_res;
htp->hrt_rem = htp->hrt_rem % htp->hrt_res;
}
interval = htp->hrt_rem;
if (interval == 0) {
htp->hrt_res = new_res;
return (0);
}
/*
* Try to do the calculations in single precision first
* (for speed). If they overflow, use double precision.
* What we want to compute is:
*
* (interval * new_res) / hrt->hrt_res
*/
numerator = interval * new_res;
if (numerator / new_res == interval) {
/*
* The above multiply didn't give overflow since
* the division got back the original number. Go
* ahead and compute the result.
*/
result = numerator / htp->hrt_res;
/*
* For HRT_RND, compute the value of:
*
* (interval * new_res) % htp->hrt_res
*
* If it is greater than half of the htp->hrt_res,
* then rounding increases the result by 1.
*
* For HRT_RNDUP, we increase the result by 1 if:
*
* result * htp->hrt_res != numerator
*
* because this tells us we truncated when calculating
* result above.
*
* We also check for overflow when incrementing result
* although this is extremely rare.
*/
if (round == HRT_RND) {
modulus = numerator - result * htp->hrt_res;
if ((twomodulus = 2 * modulus) / 2 == modulus) {
/*
* No overflow (if we overflow in calculation
* of twomodulus we fall through and use
* double precision).
*/
if (twomodulus >= htp->hrt_res) {
temp = result + 1;
if (temp - 1 == result)
result++;
else
return (-1);
}
htp->hrt_res = new_res;
htp->hrt_rem = result;
return (0);
}
} else if (round == HRT_RNDUP) {
if (result * htp->hrt_res != numerator) {
temp = result + 1;
if (temp - 1 == result)
result++;
else
return (-1);
}
htp->hrt_res = new_res;
htp->hrt_rem = result;
return (0);
} else { /* round == HRT_TRUNC */
htp->hrt_res = new_res;
htp->hrt_rem = result;
return (0);
}
}
/*
* We would get overflow doing the calculation is
* single precision so do it the slow but careful way.
*
* Compute the interval times the resolution we are
* going to.
*/
dint = interval;
dto_res = new_res;
prod = dint * dto_res;
/*
* For HRT_RND the result will be equal to:
*
* ((interval * new_res) + htp->hrt_res / 2) / htp->hrt_res
*
* and for HRT_RNDUP we use:
*
* ((interval * new_res) + htp->hrt_res - 1) / htp->hrt_res
*
* This is a different but equivalent way of rounding.
*/
if (round == HRT_RND) {
drem = htp->hrt_res / 2;
prod = prod + drem;
} else if (round == HRT_RNDUP) {
drem = htp->hrt_res - 1;
prod = prod + drem;
}
dfrom_res = htp->hrt_res;
quot = prod / dfrom_res;
/*
* If the quotient won't fit in a long, then we have
* overflow. Otherwise, return the result.
*/
if (quot > UINT_MAX) {
return (-1);
} else {
htp->hrt_res = new_res;
htp->hrt_rem = (int)quot;
return (0);
}
}
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