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 #include <unistd.h> 13 #include <sys/time.h> 14 #include <signal.h> 15 16 #define USPS 1000000 /* number of microseconds in a second */ 17 #define TICK (USPS / _sysconf(_SC_CLK_TCK)) 18 19 #define setvec(vec, a) \ 20 vec.sv_handler = a; vec.sv_mask = vec.sv_onstack = 0 21 22 static int ringring; 23 24 static void 25 sleepx(void) 26 { 27 28 ringring = 1; 29 } 30 31 void 32 usleep(unsigned n) 33 { 34 int omask; 35 struct itimerval itv, oitv; 36 struct itimerval *itp = &itv; 37 struct sigvec vec, ovec; 38 39 if (n == 0) 40 return; 41 timerclear(&itp->it_interval); 42 timerclear(&itp->it_value); 43 if (setitimer(ITIMER_REAL, itp, &oitv) < 0) 44 return; 45 itp->it_value.tv_sec = n / USPS; 46 itp->it_value.tv_usec = n % USPS; 47 if (timerisset(&oitv.it_value)) { 48 if (timercmp(&oitv.it_value, &itp->it_value, >)) { 49 oitv.it_value.tv_sec -= itp->it_value.tv_sec; 50 oitv.it_value.tv_usec -= itp->it_value.tv_usec; 51 if (oitv.it_value.tv_usec < 0) { 52 oitv.it_value.tv_usec += USPS; 53 oitv.it_value.tv_sec--; 54 } 55 } else { 56 itp->it_value = oitv.it_value; 57 oitv.it_value.tv_sec = 0; 58 oitv.it_value.tv_usec = 2 * TICK; 59 } 60 } 61 setvec(vec, sleepx); 62 (void) sigvec(SIGALRM, &vec, &ovec); 63 omask = sigblock(sigmask(SIGALRM)); 64 ringring = 0; 65 (void) setitimer(ITIMER_REAL, itp, (struct itimerval *)0); 66 while (!ringring) 67 sigpause(omask &~ sigmask(SIGALRM)); 68 (void) sigvec(SIGALRM, &ovec, (struct sigvec *)0); 69 (void) sigsetmask(omask); 70 (void) setitimer(ITIMER_REAL, &oitv, (struct itimerval *)0); 71 } 72