rt/timer_gettime.c

   1 /* Copyright (C) 2000-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If
  16    not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <pthread.h>
  20 #include <time.h>
  21
  22 #include "posix-timer.h"
  23
  24
  25 /* Get current value of timer TIMERID and store it in VALUE.  */
  26 int
  27 timer_gettime (timer_t timerid, struct itimerspec *value)
  28 {
  29   struct timer_node *timer;
  30   struct timespec now, expiry;
  31   int retval = -1, armed = 0, valid;
  32   clock_t clock = 0;
  33
  34   pthread_mutex_lock (&__timer_mutex);
  35
  36   timer = timer_id2ptr (timerid);
  37   valid = timer_valid (timer);
  38
  39   if (valid) {
  40     armed = timer->armed;
  41     expiry = timer->expirytime;
  42     clock = timer->clock;
  43     value->it_interval = timer->value.it_interval;
  44   }
  45
  46   pthread_mutex_unlock (&__timer_mutex);
  47
  48   if (valid)
  49     {
  50       if (armed)
  51         {
  52           __clock_gettime (clock, &now);
  53           if (timespec_compare (&now, &expiry) < 0)
  54             timespec_sub (&value->it_value, &expiry, &now);
  55           else
  56             {
  57               value->it_value.tv_sec = 0;
  58               value->it_value.tv_nsec = 0;
  59             }
  60         }
  61       else
  62         {
  63           value->it_value.tv_sec = 0;
  64           value->it_value.tv_nsec = 0;
  65         }
  66
  67       retval = 0;
  68     }
  69   else
  70     __set_errno (EINVAL);
  71
  72   return retval;
  73 }