xref: /minix/minix/lib/libc/sys/adjtime.c (revision 7f5f010b)
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 
39