release/src/router/apcupsd/src/lib/sleep.c

   1 /*
   2  * sleep.c
   3  *
   4  * Implementations of sleep-related functions for platforms that
   5  * do not already have them.
   6  */
   7
   8 /*
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of version 2 of the GNU General
  11  * Public License as published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public
  19  * License along with this program; if not, write to the Free
  20  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  21  * MA 02111-1307, USA.
  22  */
  23
  24 #include "apc.h"
  25
  26 #ifndef HAVE_NANOSLEEP
  27 /*
  28  * This is a close approximation of nanosleep() for platforms that
  29  * do not have it.
  30  */
  31 int nanosleep(const struct timespec *req, struct timespec *rem)
  32 {
  33    static pthread_mutex_t timer_mutex = PTHREAD_MUTEX_INITIALIZER;
  34    static pthread_cond_t timer = PTHREAD_COND_INITIALIZER;
  35    struct timespec timeout;
  36    int stat;
  37
  38    struct timeval tv;
  39
  40    /* Copy relative exit time */
  41    timeout = *req;
  42
  43    /* Compute absolute exit time */
  44    gettimeofday(&tv, NULL);
  45    timeout.tv_nsec += tv.tv_usec * 1000;
  46    timeout.tv_sec += tv.tv_sec;
  47    while (timeout.tv_nsec >= 1000000000) {
  48       timeout.tv_nsec -= 1000000000;
  49       timeout.tv_sec++;
  50    }
  51
  52    Dmsg1(200, "pthread_cond_timedwait sec=%d\n", timeout.tv_sec);
  53
  54    /* Mutex is unlocked during the timedwait */
  55    P(timer_mutex);
  56
  57    stat = pthread_cond_timedwait(&timer, &timer_mutex, &timeout);
  58    Dmsg1(200, "pthread_cond_timedwait stat=%d\n", stat);
  59
  60    V(timer_mutex);
  61
  62    /* Assume no time leftover */
  63    if (rem) {
  64       rem->tv_nsec = 0;
  65       rem->tv_sec = 0;
  66    }
  67
  68    return 0;
  69 }
  70 #endif /* HAVE_NANOSLEEP */