diff options
Diffstat (limited to 'libc/sysdeps/unix/sysv/linux/clock_gettime.c')
| -rw-r--r-- | libc/sysdeps/unix/sysv/linux/clock_gettime.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/libc/sysdeps/unix/sysv/linux/clock_gettime.c b/libc/sysdeps/unix/sysv/linux/clock_gettime.c new file mode 100644 index 000000000..5afe20feb --- /dev/null +++ b/libc/sysdeps/unix/sysv/linux/clock_gettime.c @@ -0,0 +1,193 @@ +/* clock_gettime -- Get current time from a POSIX clockid_t. Linux version. + Copyright (C) 2003,2004,2005,2006 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <sysdep.h> +#include <errno.h> +#include <time.h> +#include "kernel-posix-cpu-timers.h" +#include <kernel-features.h> + +#ifndef HAVE_CLOCK_GETTIME_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_GETTIME \ + retval = INLINE_VSYSCALL (clock_gettime, 2, clock_id, tp); \ + break + +#ifdef __ASSUME_POSIX_TIMERS + +/* This means the REALTIME and MONOTONIC clock are definitely + supported in the kernel. */ +# define SYSDEP_GETTIME \ + SYSDEP_GETTIME_CPUTIME \ + case CLOCK_REALTIME: \ + case CLOCK_MONOTONIC: \ + SYSCALL_GETTIME + +# define __libc_missing_posix_timers 0 +#elif defined __NR_clock_gettime +/* Is the syscall known to exist? */ +int __libc_missing_posix_timers attribute_hidden; + +static inline int +maybe_syscall_gettime (clockid_t clock_id, struct timespec *tp) +{ + int e = EINVAL; + + if (!__libc_missing_posix_timers) + { + INTERNAL_SYSCALL_DECL (err); + int r = INTERNAL_VSYSCALL (clock_gettime, err, 2, clock_id, tp); + if (!INTERNAL_SYSCALL_ERROR_P (r, err)) + return 0; + + e = INTERNAL_SYSCALL_ERRNO (r, err); + if (e == ENOSYS) + { + __libc_missing_posix_timers = 1; + e = EINVAL; + } + } + + return e; +} + +/* The REALTIME and MONOTONIC clock might be available. Try the + syscall first. */ +# define SYSDEP_GETTIME \ + SYSDEP_GETTIME_CPUTIME \ + case CLOCK_REALTIME: \ + case CLOCK_MONOTONIC: \ + retval = maybe_syscall_gettime (clock_id, tp); \ + if (retval == 0) \ + break; \ + /* Fallback code. */ \ + if (retval == EINVAL && clock_id == CLOCK_REALTIME) \ + retval = realtime_gettime (tp); \ + else \ + { \ + __set_errno (retval); \ + retval = -1; \ + } \ + break; +#endif + +#ifdef __NR_clock_gettime +/* We handled the REALTIME clock here. */ +# define HANDLED_REALTIME 1 +# define HANDLED_CPUTIME 1 + +# if __ASSUME_POSIX_CPU_TIMERS > 0 + +# define SYSDEP_GETTIME_CPU SYSCALL_GETTIME +# define SYSDEP_GETTIME_CPUTIME /* Default catches them too. */ + +# else + +int __libc_missing_posix_cpu_timers attribute_hidden; + +static int +maybe_syscall_gettime_cpu (clockid_t clock_id, struct timespec *tp) +{ + int e = EINVAL; + + if (!__libc_missing_posix_cpu_timers) + { + INTERNAL_SYSCALL_DECL (err); + int r = INTERNAL_VSYSCALL (clock_gettime, 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; +} + +# define SYSDEP_GETTIME_CPU \ + retval = maybe_syscall_gettime_cpu (clock_id, tp); \ + 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_gettime_cputime (clockid_t clock_id, struct timespec *tp) +{ + return maybe_syscall_gettime_cpu + (clock_id == CLOCK_THREAD_CPUTIME_ID + ? MAKE_THREAD_CPUCLOCK (0, CPUCLOCK_SCHED) + : MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED), + tp); +} + +# define SYSDEP_GETTIME_CPUTIME \ + case CLOCK_PROCESS_CPUTIME_ID: \ + case CLOCK_THREAD_CPUTIME_ID: \ + retval = maybe_syscall_gettime_cputime (clock_id, tp); \ + if (retval == 0) \ + break; \ + if (retval != EINVAL || !__libc_missing_posix_cpu_timers) \ + { \ + __set_errno (retval); \ + retval = -1; \ + break; \ + } \ + retval = hp_timing_gettime (clock_id, tp); \ + break; +# if !HP_TIMING_AVAIL +# define hp_timing_gettime(clock_id, tp) (__set_errno (EINVAL), -1) +# endif + +# endif +#endif + +#include <sysdeps/unix/clock_gettime.c> |