nanosleep.c

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Hash : 3ac95524
Author :
Date : 2007-02-12T18:49:19

New module 'time', so that apps can include <time.h> as per
POSIX and GNU instead of separate include files like time_r.h
and timegm.h.  This implementation tries out a simpler approach
for replacing decls in standard include files (as compared to
the string module), somewhat as an experiment.

* config/srclist.txt: Comment out mktime.c for now.
* doc/gnulib-tool.texi (Initial import): Don't use time_r as an example
since it doesn't apply any more.  Use generic wording instead.
* MODULES.html.sh (Support for systems lacking POSIX:2001): New module
'time'.
* lib/time_.h, m4/time_h.m4, modules/time: New files.
* lib/strptime.h, lib/time_r.h, lib/timegm.h: Remove.
* lib/mktime.c: Include config.h depending on _LIBC, not HAVE_CONFIG_H.
Don't include <sys/types.h>; no longer needed since we assume C89.
* lib/mktime.c: Don't include "time_r.h"; no longer needed.
* lib/strftime.c: Likewise.
* lib/time_r.c: Likewise.
* lib/nanosleep.c (nanosleep): #undef after include files, not before.
* lib/nanosleep.c: Include <time.h> first, to check interface.
* lib/strptime.c: Likewise.
* lib/time_r.c: Likewise.
* lib/timegm.c: Likewise.
* lib/strptime.c: Don't include strptime.h or time_r.h; no longer
needed.
* lib/timegm.c: Don't include timegm.h; no longer needed.
* lib/timespec.h: Don't include <sys/time.h> before <time.h>;
time.h now handles any problems in that area.
(struct timespec, nanosleep): Remove; time.h now arranges for these.
* lib/xnanosleep.c: Don't include timespec.h; no longer needed now
that time.h defines struct timespec.
* m4/nanosleep.m4 (gl_FUNC_NANOSLEEP): Check that nanosleep is declared.
Set REPLACE_NANOSLEEP.  Don't AC_DEFINE nanosleep; the time module now
handles that.
* m4/strptime.m4 (gl_FUNC_STPRTIME): Set REPLACE_STRPTIME.
* m4/time_r.m4 (gl_TIME_R): Don't define HAVE_TIME_R_POSIX; no longer
needed.  Set REPLACE_LOCALTIME.
* m4/timegm.m4 (gl_FUNC_TIMEGM): Set REPLACE_TIMEGM.
* m4/timespec.m4 (gl_CHECK_TYPE_STRUCT_TIMESPEC): Move to time_h.m4.
(gl_TIMESPEC): Don't check for sys/time.h or struct timespec or
nanosleep; time_h.m4 now does that.  Don't require
gl_USE_SYSTEM_EXTENSIONS; no longer needed directly, and the time
module handles this now.
* modules/getdate (Depends-on): Remove timespec.  Add time.
* modules/nanosleep (Depends-on): Likewise.
* modules/stat-time (Depends-on): Likewise.
* modules/nanosleep (Include): Include time.h, not timespec.h.
* modules/strptime (Files): Remove lib/strptime.h.
(Depends-on): Add extensions, time.
(Include): Include time.h, not strptime.h.
* modules/time_r (Files): Remove lib/time_r.h.
(Depends-on): Add time.
(Include): Include time.h, not time_r.h.
* modules/timegm: Likewise.
* modules/timespec (Description): Now does timespec-related decls
of our own, instead of struct timespec itself.
(Depends-on): Add time; remove extensions.
(Maintainer): Add self.
* modules/utimecmp (Depends-on): Add time; remove timespec.
* modules/utimens (Depends-on): Likewise.
* modules/xnanosleep (Depends-on): Likewise.

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lib/nanosleep.c

/* 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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kc3-lang/gnulib/lib/nanosleep.c

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lib/nanosleep.c