kpatch/kmod/patch/kpatch-patch-hook.c

120 lines
3.0 KiB
C

/*
* Copyright (C) 2013-2014 Josh Poimboeuf <jpoimboe@redhat.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA,
* 02110-1301, USA.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include "kpatch.h"
static bool replace;
module_param(replace, bool, S_IRUGO);
MODULE_PARM_DESC(replace, "replace all previously loaded patch modules");
extern char __kpatch_patches, __kpatch_patches_end;
extern char __kpatch_dynrelas, __kpatch_dynrelas_end;
static struct kpatch_module kpmod;
static struct kobject *patch_kobj;
static ssize_t patch_enabled_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", kpmod.enabled);
}
static ssize_t patch_enabled_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf,
size_t count)
{
int ret;
unsigned long val;
/* only disabling is supported */
if (!kpmod.enabled)
return -EINVAL;
ret = kstrtoul(buf, 10, &val);
if (ret)
return ret;
val = !!val;
/* only disabling is supported */
if (val)
return -EINVAL;
ret = kpatch_unregister(&kpmod);
if (ret)
return ret;
return count;
}
static struct kobj_attribute patch_enabled_attr =
__ATTR(enabled, 0644, patch_enabled_show, patch_enabled_store);
static int __init patch_init(void)
{
int ret;
kpmod.mod = THIS_MODULE;
kpmod.patches = (struct kpatch_patch *)&__kpatch_patches;
kpmod.patches_nr = (&__kpatch_patches_end - &__kpatch_patches) /
sizeof(*kpmod.patches);
kpmod.dynrelas = (struct kpatch_dynrela *)&__kpatch_dynrelas;
kpmod.dynrelas_nr = (&__kpatch_dynrelas_end - &__kpatch_dynrelas) /
sizeof(*kpmod.dynrelas);
patch_kobj = kobject_create_and_add(THIS_MODULE->name,
kpatch_patches_kobj);
if (!patch_kobj) {
ret = -ENOMEM;
goto err_free;
}
ret = sysfs_create_file(patch_kobj, &patch_enabled_attr.attr);
if (ret)
goto err_put;
ret = kpatch_register(&kpmod, replace);
if (ret)
goto err_sysfs;
return 0;
err_sysfs:
sysfs_remove_file(patch_kobj, &patch_enabled_attr.attr);
err_put:
kobject_put(patch_kobj);
err_free:
return ret;
}
static void __exit patch_exit(void)
{
WARN_ON(kpmod.enabled);
sysfs_remove_file(patch_kobj, &patch_enabled_attr.attr);
kobject_put(patch_kobj);
}
module_init(patch_init);
module_exit(patch_exit);
MODULE_LICENSE("GPL");