1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 * Copyright 2016 Joyent, Inc.
26 */
27
28#include <sys/types.h>
29#include <time.h>
30#include <errno.h>
31
32/*
33 * This function is blatently stolen from the kernel.
34 * See the dissertation in the comments preceding the
35 * hrt2ts() function in:
36 *	uts/common/os/timers.c
37 */
38void
39hrt2ts(hrtime_t hrt, timespec_t *tsp)
40{
41#if defined(__amd64)
42	tsp->tv_sec = hrt / NANOSEC;
43	tsp->tv_nsec = hrt % NANOSEC;
44#else
45	uint32_t sec, nsec, tmp;
46
47	tmp = (uint32_t)(hrt >> 30);
48	sec = tmp - (tmp >> 2);
49	sec = tmp - (sec >> 5);
50	sec = tmp + (sec >> 1);
51	sec = tmp - (sec >> 6) + 7;
52	sec = tmp - (sec >> 3);
53	sec = tmp + (sec >> 1);
54	sec = tmp + (sec >> 3);
55	sec = tmp + (sec >> 4);
56	tmp = (sec << 7) - sec - sec - sec;
57	tmp = (tmp << 7) - tmp - tmp - tmp;
58	tmp = (tmp << 7) - tmp - tmp - tmp;
59	nsec = (uint32_t)hrt - (tmp << 9);
60	while (nsec >= NANOSEC) {
61		nsec -= NANOSEC;
62		sec++;
63	}
64	tsp->tv_sec = (time_t)sec;
65	tsp->tv_nsec = nsec;
66#endif /* defined(__amd64) */
67}
68
69/*
70 * Convert absolute time to relative time.
71 * All *timedwait() system call traps expect relative time.
72 */
73void
74abstime_to_reltime(clockid_t clock_id, const timespec_t *abstime,
75    timespec_t *reltime)
76{
77	extern int __clock_gettime(clockid_t, timespec_t *);
78	timespec_t now;
79
80	if (clock_id == CLOCK_HIGHRES)
81		hrt2ts(gethrtime(), &now);
82	else
83		(void) __clock_gettime(clock_id, &now);
84	if (abstime->tv_nsec >= now.tv_nsec) {
85		reltime->tv_sec = abstime->tv_sec - now.tv_sec;
86		reltime->tv_nsec = abstime->tv_nsec - now.tv_nsec;
87	} else {
88		reltime->tv_sec = abstime->tv_sec - now.tv_sec - 1;
89		reltime->tv_nsec = abstime->tv_nsec - now.tv_nsec + NANOSEC;
90	}
91	/*
92	 * If the absolute time has already passed,
93	 * just set the relative time to zero.
94	 */
95	if (reltime->tv_sec < 0) {
96		reltime->tv_sec = 0;
97		reltime->tv_nsec = 0;
98	}
99	/*
100	 * If the specified absolute time has a bad nanoseconds value,
101	 * assign it to the relative time value.  If the interface
102	 * attempts to sleep, the bad value will be detected then.
103	 * The SUSV3 Posix spec is very clear that such detection
104	 * should not happen until an attempt to sleep is made.
105	 */
106	if ((ulong_t)abstime->tv_nsec >= NANOSEC)
107		reltime->tv_nsec = abstime->tv_nsec;
108}
109