librt/clock_gettime.c

   1 /* clock_gettime -- Get current time from a POSIX clockid_t.  Linux version.
   2    Copyright (C) 2003, 2004 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <sysdep.h>
  21 #include <time.h>
  22 #include <sys/time.h>
  23 #include "kernel-posix-cpu-timers.h"
  24
  25 #if defined(__UCLIBC_USE_TIME64__)
  26 #include "internal/time64_helpers.h"
  27 #endif
  28
  29 #if defined(__UCLIBC_USE_TIME64__) && defined(__NR_clock_gettime64)
  30 #define SYSCALL_GETTIME           \
  31   {                               \
  32   struct __ts64_struct __ts64;    \
  33   retval = INLINE_SYSCALL (clock_gettime64, 2, clock_id, &__ts64); \
  34   if (tp) {                       \
  35     tp->tv_sec = __ts64.tv_sec;   \
  36     tp->tv_nsec = __ts64.tv_nsec; \
  37   }                               \
  38   break;                          \
  39   }
  40 #else
  41 #define SYSCALL_GETTIME \
  42   retval = INLINE_SYSCALL (clock_gettime, 2, clock_id, tp); \
  43   break
  44 #endif
  45
  46 /* The REALTIME and MONOTONIC clock are definitely supported in the kernel.  */
  47 #define SYSDEP_GETTIME                                                        \
  48   SYSDEP_GETTIME_CPUTIME                                                      \
  49   case CLOCK_REALTIME:                                                        \
  50   case CLOCK_MONOTONIC:                                                       \
  51     SYSCALL_GETTIME
  52
  53 /* We handled the REALTIME clock here.  */
  54 #define HANDLED_REALTIME        1
  55 #define HANDLED_CPUTIME 1
  56
  57 #define SYSDEP_GETTIME_CPU SYSCALL_GETTIME
  58 #define SYSDEP_GETTIME_CPUTIME  /* Default catches them too.  */
  59
  60 static inline int
  61 realtime_gettime (struct timespec *tp)
  62 {
  63   struct timeval tv;
  64   int retval = gettimeofday (&tv, NULL);
  65   if (retval == 0)
  66     /* Convert into `timespec'.  */
  67     TIMEVAL_TO_TIMESPEC (&tv, tp);
  68   return retval;
  69 }
  70
  71 /* Get current value of CLOCK and store it in TP.  */
  72 int
  73 clock_gettime (clockid_t clock_id, struct timespec *tp)
  74 {
  75   int retval = -1;
  76 #ifndef HANDLED_REALTIME
  77   struct timeval tv;
  78 #endif
  79
  80   switch (clock_id)
  81     {
  82 #ifdef SYSDEP_GETTIME
  83       SYSDEP_GETTIME;
  84 #endif
  85
  86 #ifndef HANDLED_REALTIME
  87     case CLOCK_REALTIME:
  88       retval = gettimeofday (&tv, NULL);
  89       if (retval == 0)
  90         TIMEVAL_TO_TIMESPEC (&tv, tp);
  91       break;
  92 #endif
  93
  94     default:
  95 #ifdef SYSDEP_GETTIME_CPU
  96       SYSDEP_GETTIME_CPU;
  97 #endif
  98         __set_errno (EINVAL);
  99       break;
 100     }
 101
 102   return retval;
 103 }