efivars.c

对于那些带有区码限制的DVD光驱

	list_del(&var->list);
	spin_unlock(&efivars_lock);
	kfree(var);
}

static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);

static struct attribute *def_attrs[] = {
	&efivar_attr_guid.attr,
	&efivar_attr_size.attr,
	&efivar_attr_attributes.attr,
	&efivar_attr_data.attr,
	&efivar_attr_raw_var.attr,
	NULL,
};

static struct kobj_type ktype_efivar = {
	.release = efivar_release,
	.sysfs_ops = &efivar_attr_ops,
	.default_attrs = def_attrs,
};

static ssize_t
dummy(struct subsystem *sub, char *buf)
{
	return -ENODEV;
}

static inline void
efivar_unregister(struct efivar_entry *var)
{
	kobject_unregister(&var->kobj);
}


static ssize_t
efivar_create(struct subsystem *sub, const char *buf, size_t count)
{
	struct efi_variable *new_var = (struct efi_variable *)buf;
	struct efivar_entry *search_efivar = NULL;
	unsigned long strsize1, strsize2;
	struct list_head *pos, *n;
	efi_status_t status = EFI_NOT_FOUND;
	int found = 0;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	spin_lock(&efivars_lock);

	/*
	 * Does this variable already exist?
	 */
	list_for_each_safe(pos, n, &efivar_list) {
		search_efivar = get_efivar_entry(pos);
		strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
		strsize2 = utf8_strsize(new_var->VariableName, 1024);
		if (strsize1 == strsize2 &&
			!memcmp(&(search_efivar->var.VariableName),
				new_var->VariableName, strsize1) &&
			!efi_guidcmp(search_efivar->var.VendorGuid,
				new_var->VendorGuid)) {
			found = 1;
			break;
		}
	}
	if (found) {
		spin_unlock(&efivars_lock);
		return -EINVAL;
	}

	/* now *really* create the variable via EFI */
	status = efi.set_variable(new_var->VariableName,
			&new_var->VendorGuid,
			new_var->Attributes,
			new_var->DataSize,
			new_var->Data);

	if (status != EFI_SUCCESS) {
		printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
			status);
		spin_unlock(&efivars_lock);
		return -EIO;
	}
	spin_unlock(&efivars_lock);

	/* Create the entry in sysfs.  Locking is not required here */
	status = efivar_create_sysfs_entry(utf8_strsize(new_var->VariableName,
			1024), new_var->VariableName, &new_var->VendorGuid);
	if (status) {
		printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
	}
	return count;
}

static ssize_t
efivar_delete(struct subsystem *sub, const char *buf, size_t count)
{
	struct efi_variable *del_var = (struct efi_variable *)buf;
	struct efivar_entry *search_efivar = NULL;
	unsigned long strsize1, strsize2;
	struct list_head *pos, *n;
	efi_status_t status = EFI_NOT_FOUND;
	int found = 0;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	spin_lock(&efivars_lock);

	/*
	 * Does this variable already exist?
	 */
	list_for_each_safe(pos, n, &efivar_list) {
		search_efivar = get_efivar_entry(pos);
		strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
		strsize2 = utf8_strsize(del_var->VariableName, 1024);
		if (strsize1 == strsize2 &&
			!memcmp(&(search_efivar->var.VariableName),
				del_var->VariableName, strsize1) &&
			!efi_guidcmp(search_efivar->var.VendorGuid,
				del_var->VendorGuid)) {
			found = 1;
			break;
		}
	}
	if (!found) {
		spin_unlock(&efivars_lock);
		return -EINVAL;
	}
	/* force the Attributes/DataSize to 0 to ensure deletion */
	del_var->Attributes = 0;
	del_var->DataSize = 0;

	status = efi.set_variable(del_var->VariableName,
			&del_var->VendorGuid,
			del_var->Attributes,
			del_var->DataSize,
			del_var->Data);

	if (status != EFI_SUCCESS) {
		printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
			status);
		spin_unlock(&efivars_lock);
		return -EIO;
	}
	/* We need to release this lock before unregistering. */
	spin_unlock(&efivars_lock);

	efivar_unregister(search_efivar);

	/* It's dead Jim.... */
	return count;
}

static VAR_SUBSYS_ATTR(new_var, 0200, dummy, efivar_create);
static VAR_SUBSYS_ATTR(del_var, 0200, dummy, efivar_delete);

static struct subsys_attribute *var_subsys_attrs[] = {
	&var_subsys_attr_new_var,
	&var_subsys_attr_del_var,
	NULL,
};

/*
 * Let's not leave out systab information that snuck into
 * the efivars driver
 */
static ssize_t
systab_read(struct subsystem *entry, char *buf)
{
	char *str = buf;

	if (!entry || !buf)
		return -EINVAL;

	if (efi.mps)
		str += sprintf(str, "MPS=0x%lx\n", __pa(efi.mps));
	if (efi.acpi20)
		str += sprintf(str, "ACPI20=0x%lx\n", __pa(efi.acpi20));
	if (efi.acpi)
		str += sprintf(str, "ACPI=0x%lx\n", __pa(efi.acpi));
	if (efi.smbios)
		str += sprintf(str, "SMBIOS=0x%lx\n", __pa(efi.smbios));
	if (efi.hcdp)
		str += sprintf(str, "HCDP=0x%lx\n", __pa(efi.hcdp));
	if (efi.boot_info)
		str += sprintf(str, "BOOTINFO=0x%lx\n", __pa(efi.boot_info));
	if (efi.uga)
		str += sprintf(str, "UGA=0x%lx\n", __pa(efi.uga));

	return str - buf;
}

static EFI_ATTR(systab, 0400, systab_read, NULL);

static struct subsys_attribute *efi_subsys_attrs[] = {
	&efi_attr_systab,
	NULL,	/* maybe more in the future? */
};

static decl_subsys(vars, &ktype_efivar, NULL);
static decl_subsys(efi, NULL, NULL);

/*
 * efivar_create_sysfs_entry()
 * Requires:
 *    variable_name_size = number of bytes required to hold
 *                         variable_name (not counting the NULL
 *                         character at the end.
 *    efivars_lock is not held on entry or exit.
 * Returns 1 on failure, 0 on success
 */
static int
efivar_create_sysfs_entry(unsigned long variable_name_size,
			efi_char16_t *variable_name,
			efi_guid_t *vendor_guid)
{
	int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
	char *short_name;
	struct efivar_entry *new_efivar;

	short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
	new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);

	if (!short_name || !new_efivar)  {
		kfree(short_name);
		kfree(new_efivar);
		return 1;
	}

	memcpy(new_efivar->var.VariableName, variable_name,
		variable_name_size);
	memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));

	/* Convert Unicode to normal chars (assume top bits are 0),
	   ala UTF-8 */
	for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
		short_name[i] = variable_name[i] & 0xFF;
	}
	/* This is ugly, but necessary to separate one vendor's
	   private variables from another's.         */

	*(short_name + strlen(short_name)) = '-';
	efi_guid_unparse(vendor_guid, short_name + strlen(short_name));

	kobject_set_name(&new_efivar->kobj, "%s", short_name);
	kobj_set_kset_s(new_efivar, vars_subsys);
	kobject_register(&new_efivar->kobj);

	kfree(short_name);
	short_name = NULL;

	spin_lock(&efivars_lock);
	list_add(&new_efivar->list, &efivar_list);
	spin_unlock(&efivars_lock);

	return 0;
}
/*
 * For now we register the efi subsystem with the firmware subsystem
 * and the vars subsystem with the efi subsystem.  In the future, it
 * might make sense to split off the efi subsystem into its own
 * driver, but for now only efivars will register with it, so just
 * include it here.
 */

static int __init
efivars_init(void)
{
	efi_status_t status = EFI_NOT_FOUND;
	efi_guid_t vendor_guid;
	efi_char16_t *variable_name;
	struct subsys_attribute *attr;
	unsigned long variable_name_size = 1024;
	int i, error = 0;

	if (!efi_enabled)
		return -ENODEV;

	variable_name = kzalloc(variable_name_size, GFP_KERNEL);
	if (!variable_name) {
		printk(KERN_ERR "efivars: Memory allocation failed.\n");
		return -ENOMEM;
	}

	printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
	       EFIVARS_DATE);

	/*
	 * For now we'll register the efi subsys within this driver
	 */

	error = firmware_register(&efi_subsys);

	if (error) {
		printk(KERN_ERR "efivars: Firmware registration failed with error %d.\n", error);
		goto out_free;
	}

	kset_set_kset_s(&vars_subsys, efi_subsys);

	error = subsystem_register(&vars_subsys);

	if (error) {
		printk(KERN_ERR "efivars: Subsystem registration failed with error %d.\n", error);
		goto out_firmware_unregister;
	}

	/*
	 * Per EFI spec, the maximum storage allocated for both
	 * the variable name and variable data is 1024 bytes.
	 */

	do {
		variable_name_size = 1024;

		status = efi.get_next_variable(&variable_name_size,
						variable_name,
						&vendor_guid);
		switch (status) {
		case EFI_SUCCESS:
			efivar_create_sysfs_entry(variable_name_size,
							variable_name,
							&vendor_guid);
			break;
		case EFI_NOT_FOUND:
			break;
		default:
			printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
				status);
			status = EFI_NOT_FOUND;
			break;
		}
	} while (status != EFI_NOT_FOUND);

	/*
	 * Now add attributes to allow creation of new vars
	 * and deletion of existing ones...
	 */

	for (i = 0; (attr = var_subsys_attrs[i]) && !error; i++) {
		if (attr->show && attr->store)
			error = subsys_create_file(&vars_subsys, attr);
	}

	/* Don't forget the systab entry */

	for (i = 0; (attr = efi_subsys_attrs[i]) && !error; i++) {
		if (attr->show)
			error = subsys_create_file(&efi_subsys, attr);
	}

	if (error)
		printk(KERN_ERR "efivars: Sysfs attribute export failed with error %d.\n", error);
	else
		goto out_free;

	subsystem_unregister(&vars_subsys);

out_firmware_unregister:
	firmware_unregister(&efi_subsys);

out_free:
	kfree(variable_name);

	return error;
}

static void __exit
efivars_exit(void)
{
	struct list_head *pos, *n;

	list_for_each_safe(pos, n, &efivar_list)
		efivar_unregister(get_efivar_entry(pos));

	subsystem_unregister(&vars_subsys);
	firmware_unregister(&efi_subsys);
}

module_init(efivars_init);
module_exit(efivars_exit);