114 lines
2.9 KiB
C
114 lines
2.9 KiB
C
/*
|
|
* efibc: control EFI bootloaders which obey LoaderEntryOneShot var
|
|
* Copyright (c) 2013-2016, Intel Corporation.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms and conditions of the GNU General Public License,
|
|
* version 2, as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
|
* more details.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) "efibc: " fmt
|
|
|
|
#include <linux/efi.h>
|
|
#include <linux/module.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/slab.h>
|
|
|
|
static void efibc_str_to_str16(const char *str, efi_char16_t *str16)
|
|
{
|
|
size_t i;
|
|
|
|
for (i = 0; i < strlen(str); i++)
|
|
str16[i] = str[i];
|
|
|
|
str16[i] = '\0';
|
|
}
|
|
|
|
static int efibc_set_variable(const char *name, const char *value)
|
|
{
|
|
int ret;
|
|
efi_guid_t guid = LINUX_EFI_LOADER_ENTRY_GUID;
|
|
struct efivar_entry *entry;
|
|
size_t size = (strlen(value) + 1) * sizeof(efi_char16_t);
|
|
|
|
if (size > sizeof(entry->var.Data)) {
|
|
pr_err("value is too large (%zu bytes) for '%s' EFI variable\n", size, name);
|
|
return -EINVAL;
|
|
}
|
|
|
|
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
|
|
if (!entry) {
|
|
pr_err("failed to allocate efivar entry for '%s' EFI variable\n", name);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
efibc_str_to_str16(name, entry->var.VariableName);
|
|
efibc_str_to_str16(value, (efi_char16_t *)entry->var.Data);
|
|
memcpy(&entry->var.VendorGuid, &guid, sizeof(guid));
|
|
|
|
ret = efivar_entry_set(entry,
|
|
EFI_VARIABLE_NON_VOLATILE
|
|
| EFI_VARIABLE_BOOTSERVICE_ACCESS
|
|
| EFI_VARIABLE_RUNTIME_ACCESS,
|
|
size, entry->var.Data, NULL);
|
|
if (ret)
|
|
pr_err("failed to set %s EFI variable: 0x%x\n",
|
|
name, ret);
|
|
|
|
kfree(entry);
|
|
return ret;
|
|
}
|
|
|
|
static int efibc_reboot_notifier_call(struct notifier_block *notifier,
|
|
unsigned long event, void *data)
|
|
{
|
|
const char *reason = "shutdown";
|
|
int ret;
|
|
|
|
if (event == SYS_RESTART)
|
|
reason = "reboot";
|
|
|
|
ret = efibc_set_variable("LoaderEntryRebootReason", reason);
|
|
if (ret || !data)
|
|
return NOTIFY_DONE;
|
|
|
|
efibc_set_variable("LoaderEntryOneShot", (char *)data);
|
|
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block efibc_reboot_notifier = {
|
|
.notifier_call = efibc_reboot_notifier_call,
|
|
};
|
|
|
|
static int __init efibc_init(void)
|
|
{
|
|
int ret;
|
|
|
|
if (!efi_enabled(EFI_RUNTIME_SERVICES))
|
|
return -ENODEV;
|
|
|
|
ret = register_reboot_notifier(&efibc_reboot_notifier);
|
|
if (ret)
|
|
pr_err("unable to register reboot notifier\n");
|
|
|
|
return ret;
|
|
}
|
|
module_init(efibc_init);
|
|
|
|
static void __exit efibc_exit(void)
|
|
{
|
|
unregister_reboot_notifier(&efibc_reboot_notifier);
|
|
}
|
|
module_exit(efibc_exit);
|
|
|
|
MODULE_AUTHOR("Jeremy Compostella <jeremy.compostella@intel.com>");
|
|
MODULE_AUTHOR("Matt Gumbel <matthew.k.gumbel@intel.com");
|
|
MODULE_DESCRIPTION("EFI Bootloader Control");
|
|
MODULE_LICENSE("GPL v2");
|