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135 lines
4.0 KiB
C
135 lines
4.0 KiB
C
/* clock_getres -- Get the resolution of a POSIX clockid_t. Linux version.
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Copyright (C) 2003-2012 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include <errno.h>
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#include <time.h>
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#include "kernel-posix-cpu-timers.h"
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#include <kernel-features.h>
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#ifndef HAVE_CLOCK_GETRES_VSYSCALL
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# undef INTERNAL_VSYSCALL
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# define INTERNAL_VSYSCALL INTERNAL_SYSCALL
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# undef INLINE_VSYSCALL
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# define INLINE_VSYSCALL INLINE_SYSCALL
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#else
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# include <bits/libc-vdso.h>
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#endif
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#define SYSCALL_GETRES \
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retval = INLINE_VSYSCALL (clock_getres, 2, clock_id, res); \
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break
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/* The REALTIME and MONOTONIC clock are definitely supported in the
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kernel. */
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#define SYSDEP_GETRES \
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SYSDEP_GETRES_CPUTIME \
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case CLOCK_REALTIME: \
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case CLOCK_MONOTONIC: \
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case CLOCK_MONOTONIC_RAW: \
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case CLOCK_REALTIME_COARSE: \
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case CLOCK_MONOTONIC_COARSE: \
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SYSCALL_GETRES
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#ifdef __NR_clock_getres
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/* We handled the REALTIME clock here. */
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# define HANDLED_REALTIME 1
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# define HANDLED_CPUTIME 1
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# if __ASSUME_POSIX_CPU_TIMERS > 0
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# define SYSDEP_GETRES_CPU SYSCALL_GETRES
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# define SYSDEP_GETRES_CPUTIME /* Default catches them too. */
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# else
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extern int __libc_missing_posix_cpu_timers attribute_hidden;
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static int
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maybe_syscall_getres_cpu (clockid_t clock_id, struct timespec *res)
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{
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int e = EINVAL;
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if (!__libc_missing_posix_cpu_timers)
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{
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INTERNAL_SYSCALL_DECL (err);
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int r = INTERNAL_VSYSCALL (clock_getres, err, 2, clock_id, res);
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if (!INTERNAL_SYSCALL_ERROR_P (r, err))
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return 0;
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e = INTERNAL_SYSCALL_ERRNO (r, err);
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if (e == EINVAL)
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{
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/* Check whether the kernel supports CPU clocks at all.
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If not, record it for the future. */
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r = INTERNAL_VSYSCALL (clock_getres, err, 2,
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MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED),
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NULL);
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if (INTERNAL_SYSCALL_ERROR_P (r, err))
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__libc_missing_posix_cpu_timers = 1;
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}
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}
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return e;
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}
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# define SYSDEP_GETRES_CPU \
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retval = maybe_syscall_getres_cpu (clock_id, res); \
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if (retval == 0) \
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break; \
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if (retval != EINVAL || !__libc_missing_posix_cpu_timers) \
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{ \
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__set_errno (retval); \
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retval = -1; \
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break; \
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} \
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retval = -1 /* Otherwise continue on to the HP_TIMING version. */;
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static inline int
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maybe_syscall_getres_cputime (clockid_t clock_id, struct timespec *res)
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{
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return maybe_syscall_getres_cpu
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(clock_id == CLOCK_THREAD_CPUTIME_ID
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? MAKE_THREAD_CPUCLOCK (0, CPUCLOCK_SCHED)
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: MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED),
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res);
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}
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# define SYSDEP_GETRES_CPUTIME \
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case CLOCK_PROCESS_CPUTIME_ID: \
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case CLOCK_THREAD_CPUTIME_ID: \
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retval = maybe_syscall_getres_cputime (clock_id, res); \
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if (retval == 0) \
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break; \
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if (retval != EINVAL || !__libc_missing_posix_cpu_timers) \
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{ \
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__set_errno (retval); \
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retval = -1; \
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break; \
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} \
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retval = hp_timing_getres (res); \
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break;
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# if !HP_TIMING_AVAIL
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# define hp_timing_getres(res) (__set_errno (EINVAL), -1)
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# endif
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# endif
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#endif
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#include <sysdeps/posix/clock_getres.c>
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