glibc/sysdeps/unix/sysv/linux/clock_settime.c
2012-02-17 17:46:56 +01:00

151 lines
4.4 KiB
C

/* Copyright (C) 2003, 2004, 2006, 2010, 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 <errno.h>
#include <sysdep.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
#if __ASSUME_POSIX_CPU_TIMERS <= 0 && defined __NR_clock_settime
extern int __libc_missing_posix_timers attribute_hidden;
extern int __libc_missing_posix_cpu_timers attribute_hidden;
static int
maybe_syscall_settime_cpu (clockid_t clock_id, const struct timespec *tp)
{
int e = EINVAL;
if (!__libc_missing_posix_cpu_timers)
{
INTERNAL_SYSCALL_DECL (err);
int r = INTERNAL_SYSCALL (clock_settime, err, 2, clock_id, tp);
if (!INTERNAL_SYSCALL_ERROR_P (r, err))
return 0;
e = INTERNAL_SYSCALL_ERRNO (r, err);
# ifndef __ASSUME_POSIX_TIMERS
if (e == ENOSYS)
{
__libc_missing_posix_timers = 1;
__libc_missing_posix_cpu_timers = 1;
e = EINVAL;
}
else
# endif
{
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;
}
#endif
#ifdef __ASSUME_POSIX_TIMERS
/* This means the REALTIME clock is definitely supported in the
kernel. */
# define SYSDEP_SETTIME \
case CLOCK_REALTIME: \
retval = INLINE_SYSCALL (clock_settime, 2, clock_id, tp); \
break
#elif defined __NR_clock_settime
/* Is the syscall known to exist? */
extern int __libc_missing_posix_timers attribute_hidden;
/* The REALTIME clock might be available. Try the syscall first. */
# define SYSDEP_SETTIME \
case CLOCK_REALTIME: \
case CLOCK_REALTIME_COARSE: \
{ \
int e = EINVAL; \
\
if (!__libc_missing_posix_timers) \
{ \
INTERNAL_SYSCALL_DECL (err); \
int r = INTERNAL_SYSCALL (clock_settime, err, 2, clock_id, tp); \
if (!INTERNAL_SYSCALL_ERROR_P (r, err)) \
{ \
retval = 0; \
break; \
} \
\
e = INTERNAL_SYSCALL_ERRNO (r, err); \
if (e == ENOSYS) \
{ \
__libc_missing_posix_timers = 1; \
e = EINVAL; \
} \
} \
\
/* Fallback code. */ \
if (e == EINVAL && clock_id == CLOCK_REALTIME) \
HANDLE_REALTIME; \
else \
{ \
__set_errno (e); \
retval = -1; \
} \
} \
break
#endif
#ifdef __NR_clock_settime
/* We handled the REALTIME clock here. */
# define HANDLED_REALTIME 1
#endif
#if __ASSUME_POSIX_CPU_TIMERS > 0
# define HANDLED_CPUTIME 1
# define SYSDEP_SETTIME_CPU \
retval = INLINE_SYSCALL (clock_settime, 2, clock_id, tp)
#elif defined __NR_clock_settime
# define SYSDEP_SETTIME_CPU \
retval = maybe_syscall_settime_cpu (clock_id, tp); \
if (retval == 0) \
break; \
if (retval != EINVAL || !__libc_missing_posix_cpu_timers) \
{ \
__set_errno (retval); \
retval = -1; \
break; \
} \
do { } while (0)
#endif
#include <sysdeps/unix/clock_settime.c>