/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2023 Johannes Totz
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/efiio.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

static void
usage(void)
{
        fprintf(stderr, "Usage:\n"
            "  efiwake                          -- print out current "
                "EFI time and wake time\n"
            "  efiwake -d                       -- disable wake time\n"
            "  efiwake -e yyyy-mm-ddThh:mm:ss   -- enable wake time\n"
        );
        exit(EX_USAGE);
}

int
main(int argc, char **argv)
{
        struct efi_tm now;
        struct efi_waketime_ioc waketime;
        int ch, error, efi_fd;
        bool disable = false, enable = false;

        memset(&waketime, 0, sizeof(waketime));

        while ((ch = getopt(argc, argv, "de:")) != -1) {
                switch (ch) {
                case 'd':
                        disable = true;
                        break;
                case 'e':
                        if (sscanf(optarg,
                            "%hu-%02hhu-%02hhuT%02hhu:%02hhu:%02hhu",
                            &waketime.waketime.tm_year,
                            &waketime.waketime.tm_mon,
                            &waketime.waketime.tm_mday,
                            &waketime.waketime.tm_hour,
                            &waketime.waketime.tm_min,
                            &waketime.waketime.tm_sec) != 6) {
                                usage();
                        }
                        enable = true;
                        break;
                case '?':
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        if (argc > 0)
                usage();
        if (disable && enable)
                usage();

        efi_fd = open("/dev/efi", O_RDWR);
        if (efi_fd < 0)
                err(EX_OSERR, "cannot open /dev/efi");

        error = ioctl(efi_fd, EFIIOC_GET_TIME, &now);
        if (error != 0)
                err(EX_OSERR, "cannot get EFI time");

        /* EFI's time can be different from kernel's time. */
        printf("Current EFI time: %u-%02u-%02uT%02u:%02u:%02u\n",
            now.tm_year, now.tm_mon, now.tm_mday, now.tm_hour, now.tm_min,
            now.tm_sec);

        if (disable) {
                /*
                 * It's tempting to preserve the current timer value.
                 * However, wonky EFI implementations sometimes return bogus
                 * dates for the wake timer and would then fail disabling it
                 * here.
                 * A safe timer value is the current EFI time.
                 */
                waketime.waketime = now;
                waketime.enabled = 0;
                error = ioctl(efi_fd, EFIIOC_SET_WAKETIME, &waketime);
                if (error != 0)
                        err(EX_OSERR, "cannot disable EFI wake time");
        }
        if (enable) {
                waketime.enabled = 1;
                error = ioctl(efi_fd, EFIIOC_SET_WAKETIME, &waketime);
                if (error != 0)
                        err(EX_OSERR, "cannot enable EFI wake time");
        }

        /* Confirm to user what the wake time has been set to. */
        error = ioctl(efi_fd, EFIIOC_GET_WAKETIME, &waketime);
        if (error != 0)
                err(EX_OSERR, "cannot get EFI wake time");

        printf("EFI wake time: %u-%02u-%02uT%02u:%02u:%02u; "
            "enabled=%i, pending=%i\n",
            waketime.waketime.tm_year, waketime.waketime.tm_mon,
            waketime.waketime.tm_mday, waketime.waketime.tm_hour,
            waketime.waketime.tm_min, waketime.waketime.tm_sec,
            waketime.enabled, waketime.pending);

        close(efi_fd);
        return (0);
}