/*-
 * Copyright (c) 2016 Netflix, Inc.
 * 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
 *    in this position and unchanged.
 * 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.
 *
 * $FreeBSD: head/sys/dev/efidev/efidev.c 307391 2016-10-16 06:07:43Z kib $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/device.h>

#include <machine/efi.h>
#include <sys/efiio.h>

static struct lock efidev_lock = LOCK_INITIALIZER("efidev", 0, 0);

static d_ioctl_t efidev_ioctl;
static d_open_t efidev_open;
static d_close_t efidev_close;

static struct dev_ops efi_ops = {
        { "efi", 0, D_MPSAFE },
        .d_open = efidev_open,
        .d_close = efidev_close,
        .d_ioctl = efidev_ioctl,
};

static int
efidev_open(struct dev_open_args *ap)
{
        return 0;
}

static int
efidev_close(struct dev_close_args *ap)
{
        return 0;
}

static int
efidev_ioctl(struct dev_ioctl_args *ap)
{
        u_long cmd = ap->a_cmd;
        caddr_t addr = ap->a_data;
        int error;

        lockmgr(&efidev_lock, LK_EXCLUSIVE);

        switch (cmd) {
        case EFIIOC_GET_TABLE:
        {
                struct efi_get_table_ioc *egtioc =
                    (struct efi_get_table_ioc *)addr;

                error = efi_get_table(&egtioc->uuid, &egtioc->ptr);
                break;
        }
        case EFIIOC_GET_TIME:
        {
                struct efi_tm *tm = (struct efi_tm *)addr;

                error = efi_get_time(tm);
                break;
        }
        case EFIIOC_SET_TIME:
        {
                struct efi_tm *tm = (struct efi_tm *)addr;

                error = efi_set_time(tm);
                break;
        }
        case EFIIOC_VAR_GET:
        {
                struct efi_var_ioc *ev = (struct efi_var_ioc *)addr;
                void *data;
                efi_char *name;

                data = kmalloc(ev->datasize, M_TEMP, M_WAITOK);
                name = kmalloc(ev->namesize, M_TEMP, M_WAITOK);
                error = copyin(ev->name, name, ev->namesize);
                if (error)
                        goto vg_out;
                if (name[ev->namesize / sizeof(efi_char) - 1] != 0) {
                        error = EINVAL;
                        goto vg_out;
                }

                error = efi_var_get(name, &ev->vendor, &ev->attrib,
                    &ev->datasize, data);

                if (error == 0) {
                        error = copyout(data, ev->data, ev->datasize);
                } else if (error == EOVERFLOW) {
                        /*
                         * Pass back the size we really need, but
                         * convert the error to 0 so the copyout
                         * happens. datasize was updated in the
                         * efi_var_get call.
                         */
                        ev->data = NULL;
                        error = 0;
                }
vg_out:
                kfree(data, M_TEMP);
                kfree(name, M_TEMP);
                break;
        }
        case EFIIOC_VAR_NEXT:
        {
                struct efi_var_ioc *ev = (struct efi_var_ioc *)addr;
                efi_char *name;

                name = kmalloc(ev->namesize, M_TEMP, M_WAITOK);
                error = copyin(ev->name, name, ev->namesize);
                if (error)
                        goto vn_out;
                /* Note: namesize is the buffer size, not the string lenght */

                error = efi_var_nextname(&ev->namesize, name, &ev->vendor);
                if (error == 0) {
                        error = copyout(name, ev->name, ev->namesize);
                } else if (error == EOVERFLOW) {
                        ev->name = NULL;
                        error = 0;
                }
        vn_out:
                kfree(name, M_TEMP);
                break;
        }
        case EFIIOC_VAR_SET:
        {
                struct efi_var_ioc *ev = (struct efi_var_ioc *)addr;
                void *data = NULL;
                efi_char *name;

                /* datasize == 0 -> delete (more or less) */
                if (ev->datasize > 0)
                        data = kmalloc(ev->datasize, M_TEMP, M_WAITOK);
                name = kmalloc(ev->namesize, M_TEMP, M_WAITOK);
                if (ev->datasize) {
                        error = copyin(ev->data, data, ev->datasize);
                        if (error)
                                goto vs_out;
                }
                error = copyin(ev->name, name, ev->namesize);
                if (error)
                        goto vs_out;
                if (name[ev->namesize / sizeof(efi_char) - 1] != 0) {
                        error = EINVAL;
                        goto vs_out;
                }

                error = efi_var_set(name, &ev->vendor, ev->attrib, ev->datasize,
                    data);
vs_out:
                if (ev->datasize > 0)
                        kfree(data, M_TEMP);
                kfree(name, M_TEMP);
                break;
        }
        default:
                error = ENOTTY;
                break;
        }

        lockmgr(&efidev_lock, LK_RELEASE);

        return (error);
}

static struct cdev *efidev;

static int
efidev_modevents(module_t m, int event, void *arg __unused)
{
        switch (event) {
        case MOD_LOAD:
                efidev = make_dev(&efi_ops, 0, UID_ROOT, GID_WHEEL,
                                  0700, "efi");
                return (0);

        case MOD_UNLOAD:
                if (efidev != NULL)
                        destroy_dev(efidev);
                efidev = NULL;
                return (0);

        case MOD_SHUTDOWN:
                return (0);

        default:
                return (EOPNOTSUPP);
        }
}

static moduledata_t efidev_moddata = {
        .name = "efidev",
        .evhand = efidev_modevents,
        .priv = NULL,
};

DECLARE_MODULE(efidev, efidev_moddata, SI_SUB_PRE_DRIVERS, SI_ORDER_ANY);
MODULE_VERSION(efidev, 1);
MODULE_DEPEND(efidev, efirt, 1, 1, 1);