sleep.c revision 28033 
1/*
2 * Copyright (c) 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#if defined(LIBC_SCCS) && !defined(lint)
35static char sccsid[] = "@(#)sleep.c	8.1 (Berkeley) 6/4/93";
36#endif /* LIBC_SCCS and not lint */
37
38#include <sys/time.h>
39#include <signal.h>
40#include <unistd.h>
41#ifdef  _THREAD_SAFE
42#include <pthread.h>
43#include "pthread_private.h"
44#endif
45
46#ifndef _THREAD_SAFE
47static void
48sleephandler()
49{
50	return;
51}
52#endif	/* _THREAD_SAFE */
53
54unsigned int
55sleep(seconds)
56	unsigned int seconds;
57{
58#ifdef _THREAD_SAFE
59	struct timespec time_to_sleep;
60	struct timespec time_remaining;
61
62	if (seconds != 0) {
63		/*
64		 * XXX
65		 * Hack to work around itimerfix(9) gratuitously limiting
66		 * the acceptable range for a struct timeval.tv_sec to
67		 * <= 100000000.
68		 */
69		if (seconds > 100000000)
70			seconds = 100000000;
71		time_to_sleep.tv_sec = seconds;
72		time_to_sleep.tv_nsec = 0;
73		nanosleep(&time_to_sleep, &time_remaining);
74		seconds = time_remaining.tv_sec;
75		if (time_remaining.tv_nsec > 0)
76			seconds++;	/* round up */
77	}
78	return (seconds);
79#else
80	struct timespec time_to_sleep;
81	struct timespec time_remaining;
82	struct sigaction act, oact;
83	sigset_t mask, omask;
84
85	if (seconds != 0) {
86		/*
87		 * XXX
88		 * Hack to work around itimerfix(9) gratuitously limiting
89		 * the acceptable range for a struct timeval.tv_sec to
90		 * <= 100000000.
91		 */
92		if (seconds > 100000000)
93			seconds = 100000000;
94		time_to_sleep.tv_sec = seconds;
95		time_to_sleep.tv_nsec = 0;
96
97		/*
98		 * Set up handler to interrupt signanosleep and ensure
99		 * SIGARLM is not blocked.  Block SIGALRM while fiddling
100		 * with things.
101		 */
102		memset(&act, 0, sizeof(act));
103		act.sa_handler = sleephandler;
104		sigemptyset(&mask);
105		sigaddset(&mask, SIGALRM);
106		sigprocmask(SIG_BLOCK, &mask, &omask);
107		sigaction(SIGALRM, &act, &oact);
108		mask = omask;
109		sigdelset(&mask, SIGALRM);
110
111		/*
112		 * signanosleep() uses the given mask for the lifetime of
113		 * the syscall only - it resets on return.  Note that the
114		 * old sleep explicitly unblocks SIGALRM during the sleep.
115		 */
116		signanosleep(&time_to_sleep, &time_remaining, &mask);
117
118		/* Unwind */
119		sigaction(SIGALRM, &oact, (struct sigaction *)0);
120		sigprocmask(SIG_SETMASK, &omask, (sigset_t *)0);
121
122		/* return how long is left */
123		seconds = time_remaining.tv_sec;
124		if (time_remaining.tv_nsec > 0)
125			seconds++;	/* round up */
126	}
127	return (seconds);
128#endif	/* _THREAD_SAFE */
129}
130