minix/lib/libc/sys/adjtime.c

   1 #include <sys/cdefs.h>
   2 #include <lib.h>
   3 #include "namespace.h"
   4
   5 #include <string.h>
   6 #include <sys/time.h>
   7 #include <time.h>
   8
   9 #ifdef __weak_alias
  10 __weak_alias(adjtime, __adjtime50);
  11 #endif
  12
  13 int adjtime(const struct timeval *delta, struct timeval *olddelta)
  14 {
  15   message m;
  16
  17   memset(&m, 0, sizeof(m));
  18   m.m_lc_pm_time.clk_id = CLOCK_REALTIME;
  19   m.m_lc_pm_time.now = 0; /* use adjtime() method to slowly adjust the clock. */
  20   m.m_lc_pm_time.sec = delta->tv_sec;
  21   m.m_lc_pm_time.nsec = delta->tv_usec * 1000; /* convert usec to nsec */
  22
  23   if (_syscall(PM_PROC_NR, PM_CLOCK_SETTIME, &m) < 0)
  24         return -1;
  25
  26   if (olddelta != NULL) {
  27         /* the kernel returns immediately and the adjustment happens in the
  28          * background. Also, any currently running adjustment is stopped by
  29          * another call to adjtime(2), so the only values possible on Minix
  30          * for olddelta are those of delta.
  31          */
  32         olddelta->tv_sec = delta->tv_sec;
  33         olddelta->tv_usec = delta->tv_usec;
  34   }
  35
  36   return 0;
  37 }
  38