/* clock_gettime -- Get current time from a POSIX clockid_t. Linux version. Copyright (C) 2003, 2004 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 <bits/kernel-features.h> #define SYSCALL_GETTIME \ retval = INLINE_SYSCALL (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_SYSCALL (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_SYSCALL (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_SYSCALL (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 <errno.h> #include <stdint.h> #include <time.h> #include <sys/time.h> #include <ldsodefs.h> #if HP_TIMING_AVAIL /* Clock frequency of the processor. We make it a 64-bit variable because some jokers are already playing with processors with more than 4GHz. */ static hp_timing_t freq; /* This function is defined in the thread library. */ extern int __pthread_clock_gettime (clockid_t clock_id, hp_timing_t freq, struct timespec *tp) __attribute__ ((__weak__)); static int hp_timing_gettime (clockid_t clock_id, struct timespec *tp) { hp_timing_t tsc; if (__builtin_expect (freq == 0, 0)) { /* This can only happen if we haven't initialized the `freq' variable yet. Do this now. We don't have to protect this code against multiple execution since all of them should lead to the same result. */ freq = __get_clockfreq (); if (__builtin_expect (freq == 0, 0)) /* Something went wrong. */ return -1; } if (clock_id != CLOCK_PROCESS_CPUTIME_ID && __pthread_clock_gettime != NULL) return __pthread_clock_gettime (clock_id, freq, tp); /* Get the current counter. */ HP_TIMING_NOW (tsc); /* Compute the offset since the start time of the process. */ tsc -= GL(dl_cpuclock_offset); /* Compute the seconds. */ tp->tv_sec = tsc / freq; /* And the nanoseconds. This computation should be stable until we get machines with about 16GHz frequency. */ tp->tv_nsec = ((tsc % freq) * UINT64_C (1000000000)) / freq; return 0; } #endif static inline int realtime_gettime (struct timespec *tp) { struct timeval tv; int retval = gettimeofday (&tv, NULL); if (retval == 0) /* Convert into `timespec'. */ TIMEVAL_TO_TIMESPEC (&tv, tp); return retval; } librt_hidden_proto (clock_gettime) /* Get current value of CLOCK and store it in TP. */ int clock_gettime (clockid_t clock_id, struct timespec *tp) { int retval = -1; #ifndef HANDLED_REALTIME struct timeval tv; #endif switch (clock_id) { #ifdef SYSDEP_GETTIME SYSDEP_GETTIME; #endif #ifndef HANDLED_REALTIME case CLOCK_REALTIME: retval = gettimeofday (&tv, NULL); if (retval == 0) TIMEVAL_TO_TIMESPEC (&tv, tp); break; #endif default: #ifdef SYSDEP_GETTIME_CPU SYSDEP_GETTIME_CPU; #endif #if HP_TIMING_AVAIL if ((clock_id & ((1 << CLOCK_IDFIELD_SIZE) - 1)) == CLOCK_THREAD_CPUTIME_ID) retval = hp_timing_gettime (clock_id, tp); else #endif __set_errno (EINVAL); break; #if HP_TIMING_AVAIL && !defined HANDLED_CPUTIME case CLOCK_PROCESS_CPUTIME_ID: retval = hp_timing_gettime (clock_id, tp); break; #endif } return retval; } librt_hidden_def (clock_gettime)