diff options
Diffstat (limited to 'lib/libc/gen/sleep.c')
| -rw-r--r-- | lib/libc/gen/sleep.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/lib/libc/gen/sleep.c b/lib/libc/gen/sleep.c new file mode 100644 index 0000000..3904781 --- /dev/null +++ b/lib/libc/gen/sleep.c @@ -0,0 +1,128 @@ +/* + * 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[] = "@(#)sleep.c 8.1 (Berkeley) 6/4/93"; +#endif /* LIBC_SCCS and not lint */ + +#include <sys/time.h> +#include <signal.h> +#include <unistd.h> +#ifdef _THREAD_SAFE +#include <pthread.h> +#include "pthread_private.h" +#endif + +#ifndef _THREAD_SAFE +static void +sleephandler() +{ + return; +} +#endif /* _THREAD_SAFE */ + +unsigned int +sleep(seconds) + unsigned int seconds; +{ +#ifdef _THREAD_SAFE + struct timespec time_to_sleep; + struct timespec time_remaining; + + if (seconds != 0) { + time_to_sleep.tv_sec = seconds; + time_to_sleep.tv_nsec = 0; + (void)nanosleep(&time_to_sleep, &time_remaining); + seconds = time_remaining.tv_sec; + if (time_remaining.tv_nsec > 0) + seconds++; /* round up */ + } + return (seconds); +#else + struct timespec time_to_sleep; + struct timespec time_remaining; + struct sigaction act, oact; + sigset_t mask, omask; + int alarm_blocked; + + if (seconds != 0) { + time_to_sleep.tv_sec = seconds; + time_to_sleep.tv_nsec = 0; + + /* Block SIGALRM while fiddling with it */ + sigemptyset(&mask); + sigaddset(&mask, SIGALRM); + if (sigprocmask(SIG_BLOCK, &mask, &omask)) + return (seconds); + + /* Was SIGALRM blocked already? */ + alarm_blocked = sigismember(&omask, SIGALRM); + + if (!alarm_blocked) { + /* + * Set up handler to interrupt signanosleep only if + * SIGALRM was unblocked. (Save some syscalls) + */ + memset(&act, 0, sizeof(act)); + act.sa_handler = sleephandler; + if (sigaction(SIGALRM, &act, &oact)) { + (void)sigprocmask(SIG_SETMASK, &omask, + (sigset_t *)0); + return (seconds); + } + } + + /* + * signanosleep() uses the given mask for the lifetime of + * the syscall only - it resets on return. Note that the + * old sleep() explicitly unblocks SIGALRM during the sleep, + * we don't do that now since we don't depend on SIGALRM + * to end the timeout. If the process blocks SIGALRM, it + * gets what it asks for. + */ + (void)signanosleep(&time_to_sleep, &time_remaining, &omask); + + if (!alarm_blocked) { + /* Unwind */ + (void)sigaction(SIGALRM, &oact, (struct sigaction *)0); + (void)sigprocmask(SIG_SETMASK, &omask, (sigset_t *)0); + } + + /* return how long is left */ + seconds = time_remaining.tv_sec; + if (time_remaining.tv_nsec > 0) + seconds++; /* round up */ + } + return (seconds); +#endif /* _THREAD_SAFE */ +} |
