// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020 Intel Corporation
 * Author: Johannes Berg <johannes@sipsolutions.net>
 */
#include <stdbool.h>
#include <os.h>
#include <errno.h>
#include <sched.h>
#include <unistd.h>
#include <kern_util.h>
#include <sys/select.h>
#include <stdio.h>
#include <sys/timerfd.h>
#include "rtc.h"

static int uml_rtc_irq_fds[2];

void uml_rtc_send_timetravel_alarm(void)
{
        unsigned long long c = 1;

        CATCH_EINTR(write(uml_rtc_irq_fds[1], &c, sizeof(c)));
}

int uml_rtc_start(bool timetravel)
{
        int err;

        if (timetravel) {
                err = os_pipe(uml_rtc_irq_fds, 1, 1);
                if (err)
                        goto fail;
        } else {
                uml_rtc_irq_fds[0] = timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC);
                if (uml_rtc_irq_fds[0] < 0) {
                        err = -errno;
                        goto fail;
                }

                /* apparently timerfd won't send SIGIO, use workaround */
                sigio_broken();
                err = add_sigio_fd(uml_rtc_irq_fds[0]);
                if (err < 0) {
                        close(uml_rtc_irq_fds[0]);
                        goto fail;
                }
        }

        return uml_rtc_irq_fds[0];
fail:
        uml_rtc_stop(timetravel);
        return err;
}

int uml_rtc_enable_alarm(unsigned long long delta_seconds)
{
        struct itimerspec it = {
                .it_value = {
                        .tv_sec = delta_seconds,
                },
        };

        if (timerfd_settime(uml_rtc_irq_fds[0], 0, &it, NULL))
                return -errno;
        return 0;
}

void uml_rtc_disable_alarm(void)
{
        uml_rtc_enable_alarm(0);
}

void uml_rtc_stop(bool timetravel)
{
        if (timetravel)
                os_close_file(uml_rtc_irq_fds[1]);
        else
                ignore_sigio_fd(uml_rtc_irq_fds[0]);
        os_close_file(uml_rtc_irq_fds[0]);
}