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/* Implementation of the POSIX sleep function using nanosleep.
Copyright (C) 1996, 1997, 1998, 1999, 2003 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include <time.h>
#include <signal.h>
#include <unistd.h>
/* We are going to use the `nanosleep' syscall of the kernel. But the
kernel does not implement the sstupid SysV SIGCHLD vs. SIG_IGN
behaviour for this syscall. Therefore we have to emulate it here. */
unsigned int
__sleep (unsigned int seconds)
{
struct timespec ts = { .tv_sec = (long int) seconds, .tv_nsec = 0 };
sigset_t set, oset;
unsigned int result;
/* This is not necessary but some buggy programs depend on this. */
if (seconds == 0)
return 0;
/* Linux will wake up the system call, nanosleep, when SIGCHLD
arrives even if SIGCHLD is ignored. We have to deal with it
in libc. We block SIGCHLD first. */
if (__sigemptyset (&set) < 0
|| __sigaddset (&set, SIGCHLD) < 0
|| __sigprocmask (SIG_BLOCK, &set, &oset))
return -1;
/* If SIGCHLD is already blocked, we don't have to do anything. */
if (!__sigismember (&oset, SIGCHLD))
{
int saved_errno;
struct sigaction oact;
if (__sigemptyset (&set) < 0 || __sigaddset (&set, SIGCHLD) < 0)
return -1;
/* We get the signal handler for SIGCHLD. */
if (__sigaction (SIGCHLD, (struct sigaction *) NULL, &oact) < 0)
{
saved_errno = errno;
/* Restore the original signal mask. */
(void) __sigprocmask (SIG_SETMASK, &oset, (sigset_t *) NULL);
__set_errno (saved_errno);
return -1;
}
/* Note the sleep() is a cancellation point. But since we call
nanosleep() which itself is a cancellation point we do not
have to do anything here. */
if (oact.sa_handler == SIG_IGN)
{
/* We should leave SIGCHLD blocked. */
result = __nanosleep (&ts, &ts);
saved_errno = errno;
/* Restore the original signal mask. */
(void) __sigprocmask (SIG_SETMASK, &oset, (sigset_t *) NULL);
__set_errno (saved_errno);
}
else
{
/* We should unblock SIGCHLD. Restore the original signal mask. */
(void) __sigprocmask (SIG_SETMASK, &oset, (sigset_t *) NULL);
result = __nanosleep (&ts, &ts);
}
}
else
result = __nanosleep (&ts, &ts);
if (result != 0)
/* Round remaining time. */
result = (unsigned int) ts.tv_sec + (ts.tv_nsec >= 500000000L);
return result;
}
weak_alias (__sleep, sleep)
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