xref: /freebsd/lib/libc/gen/sleep.c (revision e627b39baccd1ec9129690167cf5e6d860509655)
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)
35 static 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 #else
45 
46 #define	setvec(vec, a) \
47 	vec.sv_handler = a; vec.sv_mask = vec.sv_onstack = 0
48 
49 static int ringring;
50 #endif
51 
52 unsigned int
53 sleep(seconds)
54 	unsigned int seconds;
55 {
56 #ifdef  _THREAD_SAFE
57     struct timespec time_to_sleep;
58     struct timespec time_remaining;
59 
60     if (seconds) {
61         time_to_sleep.tv_sec = seconds;
62         time_to_sleep.tv_nsec = 0;
63         nanosleep(&time_to_sleep,&time_remaining);
64         seconds = time_remaining.tv_sec;
65     }
66     return(seconds);
67 #else
68 	register struct itimerval *itp;
69 	struct itimerval itv, oitv;
70 	struct sigvec vec, ovec;
71 	long omask;
72 	static void sleephandler();
73 
74 	itp = &itv;
75 	if (!seconds)
76 		return 0;
77 	timerclear(&itp->it_interval);
78 	timerclear(&itp->it_value);
79 	if (setitimer(ITIMER_REAL, itp, &oitv) < 0)
80 		return seconds;
81 	itp->it_value.tv_sec = seconds;
82 	if (timerisset(&oitv.it_value)) {
83 		if (timercmp(&oitv.it_value, &itp->it_value, >))
84 			oitv.it_value.tv_sec -= itp->it_value.tv_sec;
85 		else {
86 			itp->it_value = oitv.it_value;
87 			/*
88 			 * This is a hack, but we must have time to return
89 			 * from the setitimer after the alarm or else it'll
90 			 * be restarted.  And, anyway, sleep never did
91 			 * anything more than this before.
92 			 */
93 			oitv.it_value.tv_sec = 1;
94 			oitv.it_value.tv_usec = 0;
95 		}
96 	}
97 	setvec(vec, sleephandler);
98 	(void) sigvec(SIGALRM, &vec, &ovec);
99 	omask = sigblock(sigmask(SIGALRM));
100 	ringring = 0;
101 	(void) setitimer(ITIMER_REAL, itp, (struct itimerval *)0);
102 	while (!ringring)
103 		sigpause(omask &~ sigmask(SIGALRM));
104 	(void) sigvec(SIGALRM, &ovec, (struct sigvec *)0);
105 	(void) sigsetmask(omask);
106 	(void) setitimer(ITIMER_REAL, &oitv, (struct itimerval *)0);
107 	return 0;
108 #endif
109 }
110 
111 #ifndef  _THREAD_SAFE
112 static void
113 sleephandler()
114 {
115 	ringring = 1;
116 }
117 #endif
118