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/* Implementation of the POSIX sleep function using nanosleep.
Copyright (C) 1996-2014 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, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <time.h>
#include <signal.h>
#include <string.h> /* For the real memset prototype. */
#include <unistd.h>
#include <sys/param.h>
#if 0
static void
cl (void *arg)
{
(void) __sigprocmask (SIG_SETMASK, arg, (sigset_t *) NULL);
}
#endif
/* We are going to use the `nanosleep' syscall of the kernel. But the
kernel does not implement the stupid SysV SIGCHLD vs. SIG_IGN
behaviour for this syscall. Therefore we have to emulate it here. */
unsigned int
__sleep (unsigned int seconds)
{
const unsigned int max
= (unsigned int) (((unsigned long int) (~((time_t) 0))) >> 1);
struct timespec ts;
sigset_t set, oset;
unsigned int result;
/* This is not necessary but some buggy programs depend on this. */
if (__builtin_expect (seconds == 0, 0))
{
#ifdef CANCELLATION_P
CANCELLATION_P (THREAD_SELF);
#endif
return 0;
}
ts.tv_sec = 0;
ts.tv_nsec = 0;
again:
if (sizeof (ts.tv_sec) <= sizeof (seconds))
{
/* Since SECONDS is unsigned assigning the value to .tv_sec can
overflow it. In this case we have to wait in steps. */
ts.tv_sec += MIN (seconds, max);
seconds -= (unsigned int) ts.tv_sec;
}
else
{
ts.tv_sec = (time_t) seconds;
seconds = 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. */
__sigemptyset (&set);
__sigaddset (&set, SIGCHLD);
if (__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;
__sigemptyset (&set);
__sigaddset (&set, SIGCHLD);
/* 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)
{
//__libc_cleanup_push (cl, &oset);
/* We should leave SIGCHLD blocked. */
while (1)
{
result = __nanosleep (&ts, &ts);
if (result != 0 || seconds == 0)
break;
if (sizeof (ts.tv_sec) <= sizeof (seconds))
{
ts.tv_sec = MIN (seconds, max);
seconds -= (unsigned int) ts.tv_nsec;
}
}
//__libc_cleanup_pop (0);
saved_errno = errno;
/* Restore the original signal mask. */
(void) __sigprocmask (SIG_SETMASK, &oset, (sigset_t *) NULL);
__set_errno (saved_errno);
goto out;
}
/* We should unblock SIGCHLD. Restore the original signal mask. */
(void) __sigprocmask (SIG_SETMASK, &oset, (sigset_t *) NULL);
}
result = __nanosleep (&ts, &ts);
if (result == 0 && seconds != 0)
goto again;
out:
if (result != 0)
/* Round remaining time. */
result = seconds + (unsigned int) ts.tv_sec + (ts.tv_nsec >= 500000000L);
return result;
}
weak_alias (__sleep, sleep)
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