1#define _GNU_SOURCE
2#include <sys/time.h>
3#include <sys/timex.h>
4#include <errno.h>
5#include "syscall.h"
6
7int adjtime(const struct timeval *in, struct timeval *out)
8{
9	struct timex tx = { 0 };
10	if (in) {
11		if (in->tv_sec > 1000 || in->tv_usec > 1000000000) {
12			errno = EINVAL;
13			return -1;
14		}
15		tx.offset = in->tv_sec*1000000 + in->tv_usec;
16		tx.modes = ADJ_OFFSET_SINGLESHOT;
17	}
18	if (syscall(SYS_adjtimex, &tx) < 0) return -1;
19	if (out) {
20		out->tv_sec = tx.offset / 1000000;
21		if ((out->tv_usec = tx.offset % 1000000) < 0) {
22			out->tv_sec--;
23			out->tv_usec += 1000000;
24		}
25	}
26	return 0;
27}
28