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/* Provide a replacement for the POSIX nanosleep function.
Copyright (C) 1999, 2000, 2002, 2004, 2005, 2006, 2007 Free
Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
/* written by Jim Meyering */
#include <config.h>
#include <time.h>
#include "timespec.h"
#include <stdbool.h>
#include <stdio.h>
#include <sys/types.h>
#if HAVE_SYS_SELECT_H
# include <sys/select.h>
#endif
#include <signal.h>
#include <sys/time.h>
#include <errno.h>
#include <unistd.h>
#undef nanosleep
enum { BILLION = 1000 * 1000 * 1000 };
#if HAVE_BUG_BIG_NANOSLEEP
void
getnow (struct timespec *t)
{
# if defined CLOCK_MONOTONIC && HAVE_CLOCK_GETTIME
if (clock_gettime (CLOCK_MONOTONIC, t) == 0)
return;
# endif
gettime (t);
}
int
rpl_nanosleep (const struct timespec *requested_delay,
struct timespec *remaining_delay)
{
/* nanosleep mishandles large sleeps due to internal overflow
problems, so check that the proper amount of time has actually
elapsed. */
struct timespec delay = *requested_delay;
struct timespec t0;
getnow (&t0);
for (;;)
{
int r = nanosleep (&delay, remaining_delay);
if (r == 0)
{
time_t secs_sofar;
struct timespec now;
getnow (&now);
secs_sofar = now.tv_sec - t0.tv_sec;
if (requested_delay->tv_sec < secs_sofar)
return 0;
delay.tv_sec = requested_delay->tv_sec - secs_sofar;
delay.tv_nsec = requested_delay->tv_nsec - (now.tv_nsec - t0.tv_nsec);
if (delay.tv_nsec < 0)
{
if (delay.tv_sec == 0)
return 0;
delay.tv_nsec += BILLION;
delay.tv_sec--;
}
else if (BILLION <= delay.tv_nsec)
{
delay.tv_nsec -= BILLION;
delay.tv_sec++;
}
}
}
}
#else
/* Some systems (MSDOS) don't have SIGCONT.
Using SIGTERM here turns the signal-handling code below
into a no-op on such systems. */
# ifndef SIGCONT
# define SIGCONT SIGTERM
# endif
# if ! HAVE_SIGINTERRUPT
# define siginterrupt(sig, flag) /* empty */
# endif
static sig_atomic_t volatile suspended;
/* Handle SIGCONT. */
static void
sighandler (int sig)
{
suspended = 1;
}
/* Suspend execution for at least *TS_DELAY seconds. */
static void
my_usleep (const struct timespec *ts_delay)
{
struct timeval tv_delay;
tv_delay.tv_sec = ts_delay->tv_sec;
tv_delay.tv_usec = (ts_delay->tv_nsec + 999) / 1000;
if (tv_delay.tv_usec == 1000000)
{
time_t t1 = tv_delay.tv_sec + 1;
if (t1 < tv_delay.tv_sec)
tv_delay.tv_usec = 1000000 - 1; /* close enough */
else
{
tv_delay.tv_sec = t1;
tv_delay.tv_usec = 0;
}
}
select (0, NULL, NULL, NULL, &tv_delay);
}
/* Suspend execution for at least *REQUESTED_DELAY seconds. The
*REMAINING_DELAY part isn't implemented yet. */
int
rpl_nanosleep (const struct timespec *requested_delay,
struct timespec *remaining_delay)
{
static bool initialized;
/* set up sig handler */
if (! initialized)
{
# ifdef SA_NOCLDSTOP
struct sigaction oldact, newact;
newact.sa_handler = sighandler;
sigemptyset (&newact.sa_mask);
newact.sa_flags = 0;
sigaction (SIGCONT, NULL, &oldact);
if (oldact.sa_handler != SIG_IGN)
sigaction (SIGCONT, &newact, NULL);
# else
if (signal (SIGCONT, SIG_IGN) != SIG_IGN)
{
signal (SIGCONT, sighandler);
siginterrupt (SIGCONT, 1);
}
# endif
initialized = true;
}
suspended = 0;
my_usleep (requested_delay);
if (suspended)
{
/* Calculate time remaining. */
/* FIXME: the code in sleep doesn't use this, so there's no
rush to implement it. */
errno = EINTR;
}
/* FIXME: Restore sig handler? */
return suspended;
}
#endif
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