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/* Copyright (C) 1994-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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 <stddef.h>
#include <errno.h>
#include <sys/time.h>
#include <hurd.h>
/* XXX Temporary cheezoid implementation; see __setitmr.c. */
/* These are defined in __setitmr.c. */
extern spin_lock_t _hurd_itimer_lock;
extern struct itimerval _hurd_itimerval;
extern struct timeval _hurd_itimer_started;
static inline void
subtract_timeval (struct timeval *from, const struct timeval *subtract)
{
from->tv_usec -= subtract->tv_usec;
from->tv_sec -= subtract->tv_sec;
while (from->tv_usec < 0)
{
--from->tv_sec;
from->tv_usec += 1000000;
}
}
/* Set *VALUE to the current setting of timer WHICH.
Return 0 on success, -1 on errors. */
int
__getitimer (enum __itimer_which which, struct itimerval *value)
{
struct itimerval val;
struct timeval elapsed;
switch (which)
{
default:
return __hurd_fail (EINVAL);
case ITIMER_VIRTUAL:
case ITIMER_PROF:
return __hurd_fail (ENOSYS);
case ITIMER_REAL:
break;
}
/* Get the time now. */
if (__gettimeofday (&elapsed, NULL) < 0)
return -1;
/* Extract the current timer setting; and the time it was set, so we can
calculate the time elapsed so far. */
HURD_CRITICAL_BEGIN;
__spin_lock (&_hurd_itimer_lock);
val = _hurd_itimerval;
subtract_timeval (&elapsed, &_hurd_itimer_started);
__spin_unlock (&_hurd_itimer_lock);
HURD_CRITICAL_END;
if ((val.it_value.tv_sec | val.it_value.tv_usec) != 0)
{
/* There is a pending alarm set. VAL indicates the interval it was
set for, relative to the time recorded in _hurd_itimer_started.
Now compensate for the time elapsed since to get the user's
conception of the current value of the timer (as if the value
stored decreased every microsecond). */
if (timercmp (&val.it_value, &elapsed, <))
{
/* Hmm. The timer should have just gone off, but has not been
reset. This is a possible timing glitch. The alarm will signal
soon, so fabricate a value for how soon. */
val.it_value.tv_sec = 0;
val.it_value.tv_usec = 10; /* Random. */
}
else
/* Subtract the time elapsed since the timer was set
from the current timer value the user sees. */
subtract_timeval (&val.it_value, &elapsed);
}
*value = val;
return 0;
}
weak_alias (__getitimer, getitimer)
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