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/* clock_getres -- Get the resolution of a POSIX clockid_t. Linux version.
Copyright (C) 2003-2012 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 <sysdep.h>
#include <errno.h>
#include <time.h>
#include "kernel-posix-cpu-timers.h"
#include <kernel-features.h>
#ifndef HAVE_CLOCK_GETRES_VSYSCALL
# undef INTERNAL_VSYSCALL
# define INTERNAL_VSYSCALL INTERNAL_SYSCALL
# undef INLINE_VSYSCALL
# define INLINE_VSYSCALL INLINE_SYSCALL
#else
# include <bits/libc-vdso.h>
#endif
#define SYSCALL_GETRES \
retval = INLINE_VSYSCALL (clock_getres, 2, clock_id, res); \
break
/* The REALTIME and MONOTONIC clock are definitely supported in the
kernel. */
#define SYSDEP_GETRES \
SYSDEP_GETRES_CPUTIME \
case CLOCK_REALTIME: \
case CLOCK_MONOTONIC: \
case CLOCK_MONOTONIC_RAW: \
case CLOCK_REALTIME_COARSE: \
case CLOCK_MONOTONIC_COARSE: \
SYSCALL_GETRES
#ifdef __NR_clock_getres
/* We handled the REALTIME clock here. */
# define HANDLED_REALTIME 1
# define HANDLED_CPUTIME 1
# if __ASSUME_POSIX_CPU_TIMERS > 0
# define SYSDEP_GETRES_CPU SYSCALL_GETRES
# define SYSDEP_GETRES_CPUTIME /* Default catches them too. */
# else
extern int __libc_missing_posix_cpu_timers attribute_hidden;
static int
maybe_syscall_getres_cpu (clockid_t clock_id, struct timespec *res)
{
int e = EINVAL;
if (!__libc_missing_posix_cpu_timers)
{
INTERNAL_SYSCALL_DECL (err);
int r = INTERNAL_VSYSCALL (clock_getres, err, 2, clock_id, res);
if (!INTERNAL_SYSCALL_ERROR_P (r, err))
return 0;
e = INTERNAL_SYSCALL_ERRNO (r, err);
if (e == EINVAL)
{
/* Check whether the kernel supports CPU clocks at all.
If not, record it for the future. */
r = INTERNAL_VSYSCALL (clock_getres, err, 2,
MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED),
NULL);
if (INTERNAL_SYSCALL_ERROR_P (r, err))
__libc_missing_posix_cpu_timers = 1;
}
}
return e;
}
# define SYSDEP_GETRES_CPU \
retval = maybe_syscall_getres_cpu (clock_id, res); \
if (retval == 0) \
break; \
if (retval != EINVAL || !__libc_missing_posix_cpu_timers) \
{ \
__set_errno (retval); \
retval = -1; \
break; \
} \
retval = -1 /* Otherwise continue on to the HP_TIMING version. */;
static inline int
maybe_syscall_getres_cputime (clockid_t clock_id, struct timespec *res)
{
return maybe_syscall_getres_cpu
(clock_id == CLOCK_THREAD_CPUTIME_ID
? MAKE_THREAD_CPUCLOCK (0, CPUCLOCK_SCHED)
: MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED),
res);
}
# define SYSDEP_GETRES_CPUTIME \
case CLOCK_PROCESS_CPUTIME_ID: \
case CLOCK_THREAD_CPUTIME_ID: \
retval = maybe_syscall_getres_cputime (clock_id, res); \
if (retval == 0) \
break; \
if (retval != EINVAL || !__libc_missing_posix_cpu_timers) \
{ \
__set_errno (retval); \
retval = -1; \
break; \
} \
retval = hp_timing_getres (res); \
break;
# if !HP_TIMING_AVAIL
# define hp_timing_getres(res) (__set_errno (EINVAL), -1)
# endif
# endif
#endif
#include <sysdeps/posix/clock_getres.c>
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