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/* Provide a replacement for the POSIX nanosleep function.
Copyright (C) 1999-2000, 2002, 2004-2010 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 3 of the License, 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, see <http://www.gnu.org/licenses/>. */
/* written by Jim Meyering */
#include <config.h>
#include <time.h>
#include "intprops.h"
#include "sig-handler.h"
#include "verify.h"
#include <stdbool.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/select.h>
#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
int
rpl_nanosleep (const struct timespec *requested_delay,
struct timespec *remaining_delay)
{
/* nanosleep mishandles large sleeps due to internal overflow
problems. The worst known case of this is cygwin 1.5.x, which
can't sleep more than 49.7 days (2**32 milliseconds). Solve this
by breaking the sleep up into smaller chunks. Verify that time_t
is large enough. */
verify (TYPE_MAXIMUM (time_t) / 49 / 24 / 60 / 60);
const time_t limit = 49 * 24 * 60 * 60;
time_t seconds = requested_delay->tv_sec;
struct timespec intermediate;
intermediate.tv_nsec = 0;
while (limit < seconds)
{
int result;
intermediate.tv_sec = limit;
result = nanosleep (&intermediate, remaining_delay);
seconds -= limit;
if (result)
{
if (remaining_delay)
{
remaining_delay->tv_sec += seconds;
remaining_delay->tv_nsec += requested_delay->tv_nsec;
if (BILLION <= requested_delay->tv_nsec)
{
remaining_delay->tv_sec++;
remaining_delay->tv_nsec -= BILLION;
}
}
return result;
}
}
intermediate.tv_sec = seconds;
intermediate.tv_nsec = requested_delay->tv_nsec;
return nanosleep (&intermediate, remaining_delay);
}
#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
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;
if (requested_delay->tv_nsec < 0 || BILLION <= requested_delay->tv_nsec)
{
errno = EINVAL;
return -1;
}
/* set up sig handler */
if (! initialized)
{
struct sigaction oldact;
sigaction (SIGCONT, NULL, &oldact);
if (get_handler (&oldact) != SIG_IGN)
{
struct sigaction newact;
newact.sa_handler = sighandler;
sigemptyset (&newact.sa_mask);
newact.sa_flags = 0;
sigaction (SIGCONT, &newact, NULL);
}
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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