1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright (C) 2020 Intel Corporation
 4 * Author: Johannes Berg <johannes@sipsolutions.net>
 5 */
 6#include <os.h>
 7#include <errno.h>
 8#include <sched.h>
 9#include <unistd.h>
10#include <kern_util.h>
11#include <sys/select.h>
12#include <stdio.h>
13#include <sys/timerfd.h>
14#include "rtc.h"
15
16static int uml_rtc_irq_fds[2];
17
18void uml_rtc_send_timetravel_alarm(void)
19{
20	unsigned long long c = 1;
21
22	CATCH_EINTR(write(uml_rtc_irq_fds[1], &c, sizeof(c)));
23}
24
25int uml_rtc_start(bool timetravel)
26{
27	int err;
28
29	if (timetravel) {
30		int err = os_pipe(uml_rtc_irq_fds, 1, 1);
31		if (err)
32			goto fail;
33	} else {
34		uml_rtc_irq_fds[0] = timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC);
35		if (uml_rtc_irq_fds[0] < 0) {
36			err = -errno;
37			goto fail;
38		}
39
40		/* apparently timerfd won't send SIGIO, use workaround */
41		sigio_broken(uml_rtc_irq_fds[0]);
42		err = add_sigio_fd(uml_rtc_irq_fds[0]);
43		if (err < 0) {
44			close(uml_rtc_irq_fds[0]);
45			goto fail;
46		}
47	}
48
49	return uml_rtc_irq_fds[0];
50fail:
51	uml_rtc_stop(timetravel);
52	return err;
53}
54
55int uml_rtc_enable_alarm(unsigned long long delta_seconds)
56{
57	struct itimerspec it = {
58		.it_value = {
59			.tv_sec = delta_seconds,
60		},
61	};
62
63	if (timerfd_settime(uml_rtc_irq_fds[0], 0, &it, NULL))
64		return -errno;
65	return 0;
66}
67
68void uml_rtc_disable_alarm(void)
69{
70	uml_rtc_enable_alarm(0);
71}
72
73void uml_rtc_stop(bool timetravel)
74{
75	if (timetravel)
76		os_close_file(uml_rtc_irq_fds[1]);
77	else
78		ignore_sigio_fd(uml_rtc_irq_fds[0]);
79	os_close_file(uml_rtc_irq_fds[0]);
80}