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/* Implementation of the POSIX sleep function using nanosleep.

   Copyright (C) 1996, 1997, 1998, 1999 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 Library General Public License as

   published by the Free Software Foundation; either version 2 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

   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public

   License along with the GNU C Library; see the file COPYING.LIB.  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>

#if 0

/* This is a quick and dirty, but not 100% compliant with

 * the stupid SysV SIGCHLD vs. SIG_IGN behaviour.  It is

 * fine unless you are messing with SIGCHLD...  */

unsigned int sleep (unsigned int sec)

{

        unsigned int res;

        struct timespec ts = { .tv_sec = (long int) seconds, .tv_nsec = 0 };

        res = nanosleep(&ts, &ts);

        if (res) res = (unsigned int) ts.tv_sec + (ts.tv_nsec >= 500000000L);

        return res;

}

#else

/* 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;

        }

        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;

}

#endif