int timerfd_settime(int fd, int flags,
const struct itimerspec *new_value,
struct itimerspec *old_value)
{
int timerfd, periodfd;
int ret;
uint64_t period;
struct timespec now_timespec = {0};
struct timespec rel_timespec;
timerfd = get_sibling_fd(fd, "timer");
if (timerfd < 0)
return -1;
periodfd = get_sibling_fd(fd, "period");
if (periodfd < 0) {
close(timerfd);
return -1;
}
if (old_value) {
if (__timerfd_gettime(timerfd, periodfd, old_value)) {
ret = -1;
goto out;
}
}
if (!new_value->it_value.tv_sec && !new_value->it_value.tv_nsec) {
ret = set_timer(timerfd, 0);
goto out;
}
period = timespec2tsc(&new_value->it_interval);
ret = set_period(periodfd, period);
if (ret < 0)
goto out;
/* So the caller is asking for timespecs in wall-clock time (depending
* on the clock, actually, (TODO)), and the kernel expects TSC ticks
* from boot. If !ABSTIME, then it's just relative to now. If it is
* ABSTIME, then they are asking in terms of real-world time, which
* means ABS - NOW to get the rel time, then convert to tsc ticks. */
if (flags & TFD_TIMER_ABSTIME) {
ret = clock_gettime(CLOCK_MONOTONIC, &now_timespec);
if (ret < 0)
goto out;
subtract_timespecs(&rel_timespec, &new_value->it_value,
&now_timespec);
} else {
rel_timespec = new_value->it_value;
}
ret = set_timer(timerfd, timespec2tsc(&rel_timespec) + read_tsc());
/* fall-through */
out:
close(timerfd);
close(periodfd);
return ret;
}
int timerfd_gettime(int fd, struct itimerspec *curr_value)
{
int timerfd, periodfd;
int ret;
timerfd = get_sibling_fd(fd, "timer");
if (timerfd < 0)
return -1;
periodfd = get_sibling_fd(fd, "period");
if (periodfd < 0) {
close(timerfd);
return -1;
}
ret = __timerfd_gettime(timerfd, periodfd, curr_value);
close(timerfd);
close(periodfd);
return ret;
}