1 /*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 */
7
8 #if defined(LIBC_SCCS) && !defined(lint)
9 static char sccsid[] = "@(#)sleep.c 8.1 (Berkeley) 06/04/93";
10 #endif /* LIBC_SCCS and not lint */
11
12 #include <sys/time.h>
13 #include <sys/signal.h>
14 #include <unistd.h>
15
16 #define setvec(vec, a) \
17 vec.sv_handler = a; vec.sv_mask = vec.sv_onstack = 0
18
19 static int ringring;
20
21 unsigned int
sleep(seconds)22 sleep(seconds)
23 unsigned int seconds;
24 {
25 register struct itimerval *itp;
26 struct itimerval itv, oitv;
27 struct sigvec vec, ovec;
28 long omask;
29 static void sleephandler();
30
31 itp = &itv;
32 if (!seconds)
33 return 0;
34 timerclear(&itp->it_interval);
35 timerclear(&itp->it_value);
36 if (setitimer(ITIMER_REAL, itp, &oitv) < 0)
37 return seconds;
38 itp->it_value.tv_sec = seconds;
39 if (timerisset(&oitv.it_value)) {
40 if (timercmp(&oitv.it_value, &itp->it_value, >))
41 oitv.it_value.tv_sec -= itp->it_value.tv_sec;
42 else {
43 itp->it_value = oitv.it_value;
44 /*
45 * This is a hack, but we must have time to return
46 * from the setitimer after the alarm or else it'll
47 * be restarted. And, anyway, sleep never did
48 * anything more than this before.
49 */
50 oitv.it_value.tv_sec = 1;
51 oitv.it_value.tv_usec = 0;
52 }
53 }
54 setvec(vec, sleephandler);
55 (void) sigvec(SIGALRM, &vec, &ovec);
56 omask = sigblock(sigmask(SIGALRM));
57 ringring = 0;
58 (void) setitimer(ITIMER_REAL, itp, (struct itimerval *)0);
59 while (!ringring)
60 sigpause(omask &~ sigmask(SIGALRM));
61 (void) sigvec(SIGALRM, &ovec, (struct sigvec *)0);
62 (void) sigsetmask(omask);
63 (void) setitimer(ITIMER_REAL, &oitv, (struct itimerval *)0);
64 return 0;
65 }
66
67 static void
sleephandler()68 sleephandler()
69 {
70 ringring = 1;
71 }
72