/*      $Id: shutdown_xenbus.c,v 1.9 2020/05/13 22:13:49 jdolecek Exp $ */

/*-
 * Copyright (c)2006 YAMAMOTO Takashi,
 * All rights reserved.
 *
 * 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.
 */

/*
 * Copyright (c) 2005 Manuel Bouyer.
 *
 * 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 ``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 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.
 *
 */

/*
 * watch "control/shutdown" and generate sysmon events.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: shutdown_xenbus.c,v 1.9 2020/05/13 22:13:49 jdolecek Exp $");

#include <sys/param.h>

#include <dev/sysmon/sysmonvar.h>

#include <xen/xenbus.h>
#include <xen/shutdown_xenbus.h>

#define SHUTDOWN_PATH   "control"
#define SHUTDOWN_NAME   "shutdown"

static struct sysmon_pswitch xenbus_power = {
        .smpsw_type = PSWITCH_TYPE_POWER,
        .smpsw_name = "xenbus",
};
static struct sysmon_pswitch xenbus_reset = {
        .smpsw_type = PSWITCH_TYPE_RESET,
        .smpsw_name = "xenbus",
};
static struct sysmon_pswitch xenbus_sleep = {
        .smpsw_type = PSWITCH_TYPE_SLEEP,
        .smpsw_name = "xenbus",
};

static void
xenbus_shutdown_handler(struct xenbus_watch *watch, const char **vec,
    unsigned int len)
{

        struct xenbus_transaction *xbt;
        int error;
        char reqstr[32];

again:
        xbt = xenbus_transaction_start();
        if (xbt == NULL) {
                return;
        }
        error = xenbus_read(xbt, SHUTDOWN_PATH, SHUTDOWN_NAME,
            reqstr, sizeof(reqstr));
        /* Ignore if read error or empty value */
        if (error || reqstr[0] == '\0') {
                if (error && error != ENOENT) {
                        printf("%s: xenbus_read %d\n", __func__, error);
                }
                error = xenbus_transaction_end(xbt, 1);
                if (error != 0) {
                        printf("%s: xenbus_transaction_end 1 %d\n",
                            __func__, error);
                }
                return;
        }

        /* Acknowledge the command */
        error = xenbus_write(xbt, SHUTDOWN_PATH, SHUTDOWN_NAME, "");
        if (error) {
                printf("%s: xenbus_rm %d\n", __func__, error);
        }
        error = xenbus_transaction_end(xbt, 0);
        if (error == EAGAIN) {
                goto again;
        }
        if (error != 0) {
                printf("%s: xenbus_transaction_end 2 %d\n", __func__, error);
        }
        if (strcmp(reqstr, "poweroff") == 0) {
                sysmon_pswitch_event(&xenbus_power, PSWITCH_EVENT_PRESSED);
        } else if (strcmp(reqstr, "halt") == 0) { /* XXX eventually halt without -p */
                sysmon_pswitch_event(&xenbus_power, PSWITCH_EVENT_PRESSED);
        } else if (strcmp(reqstr, "reboot") == 0) {
                sysmon_pswitch_event(&xenbus_reset, PSWITCH_EVENT_PRESSED);
        } else if (strcmp(reqstr, "suspend") == 0) {
                xen_suspend_allow = true;
                sysmon_pswitch_event(&xenbus_sleep, PSWITCH_EVENT_PRESSED);
        } else {
                printf("ignore shutdown request: %s\n", reqstr);
        }
}

static struct xenbus_watch xenbus_shutdown_watch = {
        .node = __UNCONST(SHUTDOWN_PATH "/" SHUTDOWN_NAME), /* XXX */
        .xbw_callback = xenbus_shutdown_handler,
};

void
shutdown_xenbus_setup(void)
{
        xen_suspend_allow = false;

        if (sysmon_pswitch_register(&xenbus_power) != 0 ||
            sysmon_pswitch_register(&xenbus_reset) != 0 ||
            sysmon_pswitch_register(&xenbus_sleep) != 0) {
                aprint_error("%s: unable to register with sysmon\n", __func__);
                return;
        }
        if (register_xenbus_watch(&xenbus_shutdown_watch)) {
                aprint_error("%s: unable to watch control/shutdown\n", __func__);
        }
}