linux/drivers/firmware/dmi-id.c
Hans de Goede f97a2103f1 firmware: dmi: Move product_sku info to the end of the modalias
Commit e26f023e01 ("firmware/dmi: Include product_sku info to modalias")
added a new field to the modalias in the middle of the modalias, breaking
some existing udev/hwdb matches on the whole modalias without a wildcard
('*') in between the pvr and rvn fields.

All modalias matches in e.g. :
https://github.com/systemd/systemd/blob/main/hwdb.d/60-sensor.hwdb
deliberately end in ':*' so that new fields can be added at *the end* of
the modalias, but adding a new field in the middle like this breaks things.

Move the new sku field to the end of the modalias to fix some hwdb
entries no longer matching.

The new sku field has already been put to use in 2 new hwdb entries:

 sensor:modalias:platform:HID-SENSOR-200073:dmi:*svnDell*:sku0A3E:*
  ACCEL_LOCATION=base

 sensor:modalias:platform:HID-SENSOR-200073:dmi:*svnDell*:sku0B0B:*
  ACCEL_LOCATION=base

The wildcard use before and after the sku in these matches means that they
should keep working with the sku moved to the end.

Note that there is a second instance of in essence the same problem,
commit f5152f4ded ("firmware/dmi: Report DMI Bios & EC firmware release")

Added 2 new br and efr fields in the middle of the modalias. This too
breaks some hwdb modalias matches, but this has gone unnoticed for over
a year. So some newer hwdb modalias matches actually depend on these
fields being in the middle of the string. Moving these to the end now
would break 3 hwdb entries, while fixing 8 entries.

Since there is no good answer for the new br and efr fields I have chosen
to leave these as is. Instead I'll submit a hwdb update to put a wildcard
at the place where these fields may or may not be present depending on the
kernel version.

BugLink: https://github.com/systemd/systemd/issues/20550
Link: https://github.com/systemd/systemd/pull/20562
Fixes: e26f023e01 ("firmware/dmi: Include product_sku info to modalias")
Cc: stable@vger.kernel.org
Cc: Kai-Chuan Hsieh <kaichuan.hsieh@canonical.com>
Cc: Erwan Velu <e.velu@criteo.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jean Delvare <jdelvare@suse.de>
2021-09-02 17:28:53 +02:00

260 lines
7.2 KiB
C

// 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 },
{ 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(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 struct class dmi_class = {
.name = "dmi",
.dev_release = (void(*)(struct device *)) kfree,
.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(sizeof(*dmi_dev), GFP_KERNEL);
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);