xref: /onnv-gate/usr/src/lib/libc/port/sys/time_util.c (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
28*0Sstevel@tonic-gate 
29*0Sstevel@tonic-gate #include <sys/types.h>
30*0Sstevel@tonic-gate #include <time.h>
31*0Sstevel@tonic-gate #include <errno.h>
32*0Sstevel@tonic-gate 
33*0Sstevel@tonic-gate /*
34*0Sstevel@tonic-gate  * This function is blatently stolen from the kernel.
35*0Sstevel@tonic-gate  * See the dissertation in the comments preceding the
36*0Sstevel@tonic-gate  * hrt2ts() function in:
37*0Sstevel@tonic-gate  *	uts/common/os/timers.c
38*0Sstevel@tonic-gate  */
39*0Sstevel@tonic-gate void
hrt2ts(hrtime_t hrt,timespec_t * tsp)40*0Sstevel@tonic-gate hrt2ts(hrtime_t hrt, timespec_t *tsp)
41*0Sstevel@tonic-gate {
42*0Sstevel@tonic-gate 	uint32_t sec, nsec, tmp;
43*0Sstevel@tonic-gate 
44*0Sstevel@tonic-gate 	tmp = (uint32_t)(hrt >> 30);
45*0Sstevel@tonic-gate 	sec = tmp - (tmp >> 2);
46*0Sstevel@tonic-gate 	sec = tmp - (sec >> 5);
47*0Sstevel@tonic-gate 	sec = tmp + (sec >> 1);
48*0Sstevel@tonic-gate 	sec = tmp - (sec >> 6) + 7;
49*0Sstevel@tonic-gate 	sec = tmp - (sec >> 3);
50*0Sstevel@tonic-gate 	sec = tmp + (sec >> 1);
51*0Sstevel@tonic-gate 	sec = tmp + (sec >> 3);
52*0Sstevel@tonic-gate 	sec = tmp + (sec >> 4);
53*0Sstevel@tonic-gate 	tmp = (sec << 7) - sec - sec - sec;
54*0Sstevel@tonic-gate 	tmp = (tmp << 7) - tmp - tmp - tmp;
55*0Sstevel@tonic-gate 	tmp = (tmp << 7) - tmp - tmp - tmp;
56*0Sstevel@tonic-gate 	nsec = (uint32_t)hrt - (tmp << 9);
57*0Sstevel@tonic-gate 	while (nsec >= NANOSEC) {
58*0Sstevel@tonic-gate 		nsec -= NANOSEC;
59*0Sstevel@tonic-gate 		sec++;
60*0Sstevel@tonic-gate 	}
61*0Sstevel@tonic-gate 	tsp->tv_sec = (time_t)sec;
62*0Sstevel@tonic-gate 	tsp->tv_nsec = nsec;
63*0Sstevel@tonic-gate }
64*0Sstevel@tonic-gate 
65*0Sstevel@tonic-gate /*
66*0Sstevel@tonic-gate  * Convert absolute time to relative time.
67*0Sstevel@tonic-gate  * All *timedwait() system call traps expect relative time.
68*0Sstevel@tonic-gate  */
69*0Sstevel@tonic-gate void
abstime_to_reltime(clockid_t clock_id,const timespec_t * abstime,timespec_t * reltime)70*0Sstevel@tonic-gate abstime_to_reltime(clockid_t clock_id,
71*0Sstevel@tonic-gate 	const timespec_t *abstime, timespec_t *reltime)
72*0Sstevel@tonic-gate {
73*0Sstevel@tonic-gate 	extern int __clock_gettime(clockid_t, timespec_t *);
74*0Sstevel@tonic-gate 	timespec_t now;
75*0Sstevel@tonic-gate 
76*0Sstevel@tonic-gate 	if (clock_id == CLOCK_HIGHRES)
77*0Sstevel@tonic-gate 		hrt2ts(gethrtime(), &now);
78*0Sstevel@tonic-gate 	else
79*0Sstevel@tonic-gate 		(void) __clock_gettime(clock_id, &now);
80*0Sstevel@tonic-gate 	if (abstime->tv_nsec >= now.tv_nsec) {
81*0Sstevel@tonic-gate 		reltime->tv_sec = abstime->tv_sec - now.tv_sec;
82*0Sstevel@tonic-gate 		reltime->tv_nsec = abstime->tv_nsec - now.tv_nsec;
83*0Sstevel@tonic-gate 	} else {
84*0Sstevel@tonic-gate 		reltime->tv_sec = abstime->tv_sec - now.tv_sec - 1;
85*0Sstevel@tonic-gate 		reltime->tv_nsec = abstime->tv_nsec - now.tv_nsec + NANOSEC;
86*0Sstevel@tonic-gate 	}
87*0Sstevel@tonic-gate 	/*
88*0Sstevel@tonic-gate 	 * If the absolute time has already passed,
89*0Sstevel@tonic-gate 	 * just set the relative time to zero.
90*0Sstevel@tonic-gate 	 */
91*0Sstevel@tonic-gate 	if (reltime->tv_sec < 0) {
92*0Sstevel@tonic-gate 		reltime->tv_sec = 0;
93*0Sstevel@tonic-gate 		reltime->tv_nsec = 0;
94*0Sstevel@tonic-gate 	}
95*0Sstevel@tonic-gate 	/*
96*0Sstevel@tonic-gate 	 * If the specified absolute time has a bad nanoseconds value,
97*0Sstevel@tonic-gate 	 * assign it to the relative time value.  If the interface
98*0Sstevel@tonic-gate 	 * attempts to sleep, the bad value will be detected then.
99*0Sstevel@tonic-gate 	 * The SUSV3 Posix spec is very clear that such detection
100*0Sstevel@tonic-gate 	 * should not happen until an attempt to sleep is made.
101*0Sstevel@tonic-gate 	 */
102*0Sstevel@tonic-gate 	if ((ulong_t)abstime->tv_nsec >= NANOSEC)
103*0Sstevel@tonic-gate 		reltime->tv_nsec = abstime->tv_nsec;
104*0Sstevel@tonic-gate }
105