1 /* 2 * Copyright 1996 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 */ 5 6 /* 7 * Copyright (c) 1985 Regents of the University of California. 8 * All rights reserved. The Berkeley software License Agreement 9 * specifies the terms and conditions for redistribution. 10 */ 11 12 #pragma ident "%Z%%M% %I% %E% SMI" 13 14 #include <unistd.h> 15 #include <sys/time.h> 16 #include <signal.h> 17 18 #define USPS 1000000 /* number of microseconds in a second */ 19 #define TICK (USPS / _sysconf(_SC_CLK_TCK)) 20 21 #define setvec(vec, a) \ 22 vec.sv_handler = a; vec.sv_mask = vec.sv_onstack = 0 23 24 static int ringring; 25 26 void 27 usleep(unsigned n) 28 { 29 static void sleepx(); 30 int omask; 31 struct itimerval itv, oitv; 32 struct itimerval *itp = &itv; 33 struct sigvec vec, ovec; 34 35 if (n == 0) 36 return; 37 timerclear(&itp->it_interval); 38 timerclear(&itp->it_value); 39 if (setitimer(ITIMER_REAL, itp, &oitv) < 0) 40 return; 41 itp->it_value.tv_sec = n / USPS; 42 itp->it_value.tv_usec = n % USPS; 43 if (timerisset(&oitv.it_value)) { 44 if (timercmp(&oitv.it_value, &itp->it_value, >)) { 45 oitv.it_value.tv_sec -= itp->it_value.tv_sec; 46 oitv.it_value.tv_usec -= itp->it_value.tv_usec; 47 if (oitv.it_value.tv_usec < 0) { 48 oitv.it_value.tv_usec += USPS; 49 oitv.it_value.tv_sec--; 50 } 51 } else { 52 itp->it_value = oitv.it_value; 53 oitv.it_value.tv_sec = 0; 54 oitv.it_value.tv_usec = 2 * TICK; 55 } 56 } 57 setvec(vec, sleepx); 58 (void) sigvec(SIGALRM, &vec, &ovec); 59 omask = sigblock(sigmask(SIGALRM)); 60 ringring = 0; 61 (void) setitimer(ITIMER_REAL, itp, (struct itimerval *)0); 62 while (!ringring) 63 sigpause(omask &~ sigmask(SIGALRM)); 64 (void) sigvec(SIGALRM, &ovec, (struct sigvec *)0); 65 (void) sigsetmask(omask); 66 (void) setitimer(ITIMER_REAL, &oitv, (struct itimerval *)0); 67 } 68 69 static void 70 sleepx(void) 71 { 72 73 ringring = 1; 74 } 75