lib/monotonic.c

   1 /*
   2  * Please, don't add this file to libcommon because clock_gettime() requires
   3  * -lrt on systems with old libc.
   4  *
   5  * No copyright is claimed.  This code is in the public domain; do with
   6  * it what you wish.
   7  */
   8 #include <time.h>
   9 #include <signal.h>
  10 #ifdef HAVE_SYSINFO
  11 #include <sys/sysinfo.h>
  12 #endif
  13 #include <sys/time.h>
  14
  15 #include "c.h"
  16 #include "monotonic.h"
  17
  18 int get_boot_time(struct timeval *boot_time)
  19 {
  20 #ifdef CLOCK_BOOTTIME
  21         struct timespec hires_uptime;
  22         struct timeval lores_uptime;
  23 #endif
  24         struct timeval now;
  25 #ifdef HAVE_SYSINFO
  26         struct sysinfo info;
  27 #endif
  28
  29         if (gettimeofday(&now, NULL) != 0)
  30                 return -errno;
  31 #ifdef CLOCK_BOOTTIME
  32         if (clock_gettime(CLOCK_BOOTTIME, &hires_uptime) == 0) {
  33                 TIMESPEC_TO_TIMEVAL(&lores_uptime, &hires_uptime);
  34                 timersub(&now, &lores_uptime, boot_time);
  35                 return 0;
  36         }
  37 #endif
  38 #ifdef HAVE_SYSINFO
  39         /* fallback */
  40         if (sysinfo(&info) != 0)
  41                 return -errno;
  42
  43         boot_time->tv_sec = now.tv_sec - info.uptime;
  44         boot_time->tv_usec = 0;
  45         return 0;
  46 #else
  47         return -ENOSYS;
  48 #endif
  49 }
  50
  51 int gettime_monotonic(struct timeval *tv)
  52 {
  53 #ifdef CLOCK_MONOTONIC
  54         /* Can slew only by ntp and adjtime */
  55         int ret;
  56         struct timespec ts;
  57
  58         /* Linux specific, can't slew */
  59         if (!(ret = clock_gettime(UL_CLOCK_MONOTONIC, &ts))) {
  60                 tv->tv_sec = ts.tv_sec;
  61                 tv->tv_usec = ts.tv_nsec / 1000;
  62         }
  63         return ret;
  64 #else
  65         return gettimeofday(tv, NULL);
  66 #endif
  67 }
  68
  69