cregit-Linux how code gets into the kernel

Release 4.11 drivers/firmware/efi/efibc.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'; }

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Jeremy Compostella51100.00%1100.00%
Total51100.00%1100.00%


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; }

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Jeremy Compostella193100.00%3100.00%
Total193100.00%3100.00%


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; }

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Jeremy Compostella72100.00%2100.00%
Total72100.00%2100.00%

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; }

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Jeremy Compostella44100.00%1100.00%
Total44100.00%1100.00%

module_init(efibc_init);
static void __exit efibc_exit(void) { unregister_reboot_notifier(&efibc_reboot_notifier); }

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Jeremy Compostella15100.00%1100.00%
Total15100.00%1100.00%

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");

Overall Contributors

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Jeremy Compostella437100.00%3100.00%
Total437100.00%3100.00%
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