diff options
Diffstat (limited to 'lib/libc/gen/usleep.c')
| -rw-r--r-- | lib/libc/gen/usleep.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/lib/libc/gen/usleep.c b/lib/libc/gen/usleep.c new file mode 100644 index 0000000..9127bfc --- /dev/null +++ b/lib/libc/gen/usleep.c @@ -0,0 +1,99 @@ +/* + * Copyright (c) 1989, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "@(#)usleep.c 8.1 (Berkeley) 6/4/93"; +#endif /* LIBC_SCCS and not lint */ + +#include <sys/time.h> +#include <sys/signal.h> +#include <unistd.h> + +#define TICK 10000 /* system clock resolution in microseconds */ +#define USPS 1000000 /* number of microseconds in a second */ + +#define setvec(vec, a) \ + vec.sv_handler = a; vec.sv_mask = vec.sv_onstack = 0 + +static int ringring; + +void +usleep(useconds) + unsigned int useconds; +{ + register struct itimerval *itp; + struct itimerval itv, oitv; + struct sigvec vec, ovec; + long omask; + static void sleephandler(); + + itp = &itv; + if (!useconds) + return; + timerclear(&itp->it_interval); + timerclear(&itp->it_value); + if (setitimer(ITIMER_REAL, itp, &oitv) < 0) + return; + itp->it_value.tv_sec = useconds / USPS; + itp->it_value.tv_usec = useconds % USPS; + if (timerisset(&oitv.it_value)) { + if (timercmp(&oitv.it_value, &itp->it_value, >)) { + oitv.it_value.tv_sec -= itp->it_value.tv_sec; + oitv.it_value.tv_usec -= itp->it_value.tv_usec; + if (oitv.it_value.tv_usec < 0) { + oitv.it_value.tv_usec += USPS; + oitv.it_value.tv_sec--; + } + } else { + itp->it_value = oitv.it_value; + oitv.it_value.tv_sec = 0; + oitv.it_value.tv_usec = 2 * TICK; + } + } + setvec(vec, sleephandler); + (void) sigvec(SIGALRM, &vec, &ovec); + omask = sigblock(sigmask(SIGALRM)); + ringring = 0; + (void) setitimer(ITIMER_REAL, itp, (struct itimerval *)0); + while (!ringring) + sigpause(omask &~ sigmask(SIGALRM)); + (void) sigvec(SIGALRM, &ovec, (struct sigvec *)0); + (void) sigsetmask(omask); + (void) setitimer(ITIMER_REAL, &oitv, (struct itimerval *)0); +} + +static void +sleephandler() +{ + ringring = 1; +} |
