// SPDX-License-Identifier: GPL-2.0-only
/*
 * Export SMBIOS/DMI info via sysfs to userspace
 *
 * Copyright 2007, Lennart Poettering
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/dmi.h>
#include <linux/device.h>
#include <linux/slab.h>

struct dmi_device_attribute{
        struct device_attribute dev_attr;
        int field;
};
#define to_dmi_dev_attr(_dev_attr) \
        container_of(_dev_attr, struct dmi_device_attribute, dev_attr)

static ssize_t sys_dmi_field_show(struct device *dev,
                                  struct device_attribute *attr,
                                  char *page)
{
        int field = to_dmi_dev_attr(attr)->field;
        ssize_t len;
        len = scnprintf(page, PAGE_SIZE, "%s\n", dmi_get_system_info(field));
        page[len-1] = '\n';
        return len;
}

#define DMI_ATTR(_name, _mode, _show, _field)                   \
        { .dev_attr = __ATTR(_name, _mode, _show, NULL),        \
          .field = _field }

#define DEFINE_DMI_ATTR_WITH_SHOW(_name, _mode, _field)         \
static struct dmi_device_attribute sys_dmi_##_name##_attr =     \
        DMI_ATTR(_name, _mode, sys_dmi_field_show, _field);

DEFINE_DMI_ATTR_WITH_SHOW(bios_vendor,          0444, DMI_BIOS_VENDOR);
DEFINE_DMI_ATTR_WITH_SHOW(bios_version,         0444, DMI_BIOS_VERSION);
DEFINE_DMI_ATTR_WITH_SHOW(bios_date,            0444, DMI_BIOS_DATE);
DEFINE_DMI_ATTR_WITH_SHOW(sys_vendor,           0444, DMI_SYS_VENDOR);
DEFINE_DMI_ATTR_WITH_SHOW(bios_release,         0444, DMI_BIOS_RELEASE);
DEFINE_DMI_ATTR_WITH_SHOW(ec_firmware_release,  0444, DMI_EC_FIRMWARE_RELEASE);
DEFINE_DMI_ATTR_WITH_SHOW(product_name,         0444, DMI_PRODUCT_NAME);
DEFINE_DMI_ATTR_WITH_SHOW(product_version,      0444, DMI_PRODUCT_VERSION);
DEFINE_DMI_ATTR_WITH_SHOW(product_serial,       0400, DMI_PRODUCT_SERIAL);
DEFINE_DMI_ATTR_WITH_SHOW(product_uuid,         0400, DMI_PRODUCT_UUID);
DEFINE_DMI_ATTR_WITH_SHOW(product_sku,          0444, DMI_PRODUCT_SKU);
DEFINE_DMI_ATTR_WITH_SHOW(product_family,       0444, DMI_PRODUCT_FAMILY);
DEFINE_DMI_ATTR_WITH_SHOW(board_vendor,         0444, DMI_BOARD_VENDOR);
DEFINE_DMI_ATTR_WITH_SHOW(board_name,           0444, DMI_BOARD_NAME);
DEFINE_DMI_ATTR_WITH_SHOW(board_version,        0444, DMI_BOARD_VERSION);
DEFINE_DMI_ATTR_WITH_SHOW(board_serial,         0400, DMI_BOARD_SERIAL);
DEFINE_DMI_ATTR_WITH_SHOW(board_asset_tag,      0444, DMI_BOARD_ASSET_TAG);
DEFINE_DMI_ATTR_WITH_SHOW(chassis_vendor,       0444, DMI_CHASSIS_VENDOR);
DEFINE_DMI_ATTR_WITH_SHOW(chassis_type,         0444, DMI_CHASSIS_TYPE);
DEFINE_DMI_ATTR_WITH_SHOW(chassis_version,      0444, DMI_CHASSIS_VERSION);
DEFINE_DMI_ATTR_WITH_SHOW(chassis_serial,       0400, DMI_CHASSIS_SERIAL);
DEFINE_DMI_ATTR_WITH_SHOW(chassis_asset_tag,    0444, DMI_CHASSIS_ASSET_TAG);

static void ascii_filter(char *d, const char *s)
{
        /* Filter out characters we don't want to see in the modalias string */
        for (; *s; s++)
                if (*s > ' ' && *s < 127 && *s != ':')
                        *(d++) = *s;

        *d = 0;
}

static ssize_t get_modalias(char *buffer, size_t buffer_size)
{
        /*
         * Note new fields need to be added at the end to keep compatibility
         * with udev's hwdb which does matches on "`cat dmi/id/modalias`*".
         */
        static const struct mafield {
                const char *prefix;
                int field;
        } fields[] = {
                { "bvn", DMI_BIOS_VENDOR },
                { "bvr", DMI_BIOS_VERSION },
                { "bd",  DMI_BIOS_DATE },
                { "br",  DMI_BIOS_RELEASE },
                { "efr", DMI_EC_FIRMWARE_RELEASE },
                { "svn", DMI_SYS_VENDOR },
                { "pn",  DMI_PRODUCT_NAME },
                { "pvr", DMI_PRODUCT_VERSION },
                { "rvn", DMI_BOARD_VENDOR },
                { "rn",  DMI_BOARD_NAME },
                { "rvr", DMI_BOARD_VERSION },
                { "cvn", DMI_CHASSIS_VENDOR },
                { "ct",  DMI_CHASSIS_TYPE },
                { "cvr", DMI_CHASSIS_VERSION },
                { "sku", DMI_PRODUCT_SKU },
                { "pfa", DMI_PRODUCT_FAMILY },
                { NULL,  DMI_NONE }
        };

        ssize_t l, left;
        char *p;
        const struct mafield *f;

        strcpy(buffer, "dmi");
        p = buffer + 3; left = buffer_size - 4;

        for (f = fields; f->prefix && left > 0; f++) {
                const char *c;
                char *t;

                c = dmi_get_system_info(f->field);
                if (!c)
                        continue;

                t = kmalloc(strlen(c) + 1, GFP_KERNEL);
                if (!t)
                        break;
                ascii_filter(t, c);
                l = scnprintf(p, left, ":%s%s", f->prefix, t);
                kfree(t);

                p += l;
                left -= l;
        }

        p[0] = ':';
        p[1] = 0;

        return p - buffer + 1;
}

static ssize_t sys_dmi_modalias_show(struct device *dev,
                                     struct device_attribute *attr, char *page)
{
        ssize_t r;
        r = get_modalias(page, PAGE_SIZE-1);
        page[r] = '\n';
        page[r+1] = 0;
        return r+1;
}

static struct device_attribute sys_dmi_modalias_attr =
        __ATTR(modalias, 0444, sys_dmi_modalias_show, NULL);

static struct attribute *sys_dmi_attributes[DMI_STRING_MAX+2];

static struct attribute_group sys_dmi_attribute_group = {
        .attrs = sys_dmi_attributes,
};

static const struct attribute_group* sys_dmi_attribute_groups[] = {
        &sys_dmi_attribute_group,
        NULL
};

static int dmi_dev_uevent(const struct device *dev, struct kobj_uevent_env *env)
{
        ssize_t len;

        if (add_uevent_var(env, "MODALIAS="))
                return -ENOMEM;
        len = get_modalias(&env->buf[env->buflen - 1],
                           sizeof(env->buf) - env->buflen);
        if (len >= (sizeof(env->buf) - env->buflen))
                return -ENOMEM;
        env->buflen += len;
        return 0;
}

static void dmi_dev_release(struct device *dev)
{
        kfree(dev);
}

static struct class dmi_class = {
        .name = "dmi",
        .dev_release = dmi_dev_release,
        .dev_uevent = dmi_dev_uevent,
};

static struct device *dmi_dev;

/* Initialization */

#define ADD_DMI_ATTR(_name, _field) \
        if (dmi_get_system_info(_field)) \
                sys_dmi_attributes[i++] = &sys_dmi_##_name##_attr.dev_attr.attr;

/* In a separate function to keep gcc 3.2 happy - do NOT merge this in
   dmi_id_init! */
static void __init dmi_id_init_attr_table(void)
{
        int i;

        /* Not necessarily all DMI fields are available on all
         * systems, hence let's built an attribute table of just
         * what's available */
        i = 0;
        ADD_DMI_ATTR(bios_vendor,       DMI_BIOS_VENDOR);
        ADD_DMI_ATTR(bios_version,      DMI_BIOS_VERSION);
        ADD_DMI_ATTR(bios_date,         DMI_BIOS_DATE);
        ADD_DMI_ATTR(bios_release,      DMI_BIOS_RELEASE);
        ADD_DMI_ATTR(ec_firmware_release, DMI_EC_FIRMWARE_RELEASE);
        ADD_DMI_ATTR(sys_vendor,        DMI_SYS_VENDOR);
        ADD_DMI_ATTR(product_name,      DMI_PRODUCT_NAME);
        ADD_DMI_ATTR(product_version,   DMI_PRODUCT_VERSION);
        ADD_DMI_ATTR(product_serial,    DMI_PRODUCT_SERIAL);
        ADD_DMI_ATTR(product_uuid,      DMI_PRODUCT_UUID);
        ADD_DMI_ATTR(product_family,    DMI_PRODUCT_FAMILY);
        ADD_DMI_ATTR(product_sku,       DMI_PRODUCT_SKU);
        ADD_DMI_ATTR(board_vendor,      DMI_BOARD_VENDOR);
        ADD_DMI_ATTR(board_name,        DMI_BOARD_NAME);
        ADD_DMI_ATTR(board_version,     DMI_BOARD_VERSION);
        ADD_DMI_ATTR(board_serial,      DMI_BOARD_SERIAL);
        ADD_DMI_ATTR(board_asset_tag,   DMI_BOARD_ASSET_TAG);
        ADD_DMI_ATTR(chassis_vendor,    DMI_CHASSIS_VENDOR);
        ADD_DMI_ATTR(chassis_type,      DMI_CHASSIS_TYPE);
        ADD_DMI_ATTR(chassis_version,   DMI_CHASSIS_VERSION);
        ADD_DMI_ATTR(chassis_serial,    DMI_CHASSIS_SERIAL);
        ADD_DMI_ATTR(chassis_asset_tag, DMI_CHASSIS_ASSET_TAG);
        sys_dmi_attributes[i++] = &sys_dmi_modalias_attr.attr;
}

static int __init dmi_id_init(void)
{
        int ret;

        if (!dmi_available)
                return -ENODEV;

        dmi_id_init_attr_table();

        ret = class_register(&dmi_class);
        if (ret)
                return ret;

        dmi_dev = kzalloc_obj(*dmi_dev);
        if (!dmi_dev) {
                ret = -ENOMEM;
                goto fail_class_unregister;
        }

        dmi_dev->class = &dmi_class;
        dev_set_name(dmi_dev, "id");
        dmi_dev->groups = sys_dmi_attribute_groups;

        ret = device_register(dmi_dev);
        if (ret)
                goto fail_put_dmi_dev;

        return 0;

fail_put_dmi_dev:
        put_device(dmi_dev);

fail_class_unregister:
        class_unregister(&dmi_class);

        return ret;
}

arch_initcall(dmi_id_init);