kernel_optimize_test/kernel/ksysfs.c
Kay Sievers 0f76e5acf9 [PATCH] add uevent_helper control in /sys/kernel/
This deprecates the /proc/sys/kernel/hotplug file, as all
this stuff should be in /sys some day, right? :)
In /sys/kernel/ we have now uevent_seqnum and uevent_helper.
The seqnum is no longer used by udev, as the version for this
kernel depends on netlink which events will never get
out-of-order.

Recent udev versions disable the /sbin/hotplug helper with
an init script, cause it leads to OOM on big boxes by running
hundreds of shells in parallel. It should be done now by:
  echo "" > /sys/kernel/uevent_helper

(Note that "-n" does not work, cause neighter proc nor sysfs
support truncate().)

Signed-off-by: Kay Sievers <kay.sievers@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-04 16:18:07 -08:00

90 lines
2.1 KiB
C

/*
* kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
* are not related to any other subsystem
*
* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
*
* This file is release under the GPLv2
*
*/
#include <linux/config.h>
#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/init.h>
#define KERNEL_ATTR_RO(_name) \
static struct subsys_attribute _name##_attr = __ATTR_RO(_name)
#define KERNEL_ATTR_RW(_name) \
static struct subsys_attribute _name##_attr = \
__ATTR(_name, 0644, _name##_show, _name##_store)
#ifdef CONFIG_HOTPLUG
/* current uevent sequence number */
static ssize_t uevent_seqnum_show(struct subsystem *subsys, char *page)
{
return sprintf(page, "%llu\n", (unsigned long long)hotplug_seqnum);
}
KERNEL_ATTR_RO(uevent_seqnum);
/* uevent helper program, used during early boo */
static ssize_t uevent_helper_show(struct subsystem *subsys, char *page)
{
return sprintf(page, "%s\n", hotplug_path);
}
static ssize_t uevent_helper_store(struct subsystem *subsys, const char *page, size_t count)
{
if (count+1 > HOTPLUG_PATH_LEN)
return -ENOENT;
memcpy(hotplug_path, page, count);
hotplug_path[count] = '\0';
if (count && hotplug_path[count-1] == '\n')
hotplug_path[count-1] = '\0';
return count;
}
KERNEL_ATTR_RW(uevent_helper);
#endif
#ifdef CONFIG_KEXEC
#include <asm/kexec.h>
static ssize_t crash_notes_show(struct subsystem *subsys, char *page)
{
return sprintf(page, "%p\n", (void *)crash_notes);
}
KERNEL_ATTR_RO(crash_notes);
#endif
decl_subsys(kernel, NULL, NULL);
EXPORT_SYMBOL_GPL(kernel_subsys);
static struct attribute * kernel_attrs[] = {
#ifdef CONFIG_HOTPLUG
&uevent_seqnum_attr.attr,
&uevent_helper_attr.attr,
#endif
#ifdef CONFIG_KEXEC
&crash_notes_attr.attr,
#endif
NULL
};
static struct attribute_group kernel_attr_group = {
.attrs = kernel_attrs,
};
static int __init ksysfs_init(void)
{
int error = subsystem_register(&kernel_subsys);
if (!error)
error = sysfs_create_group(&kernel_subsys.kset.kobj,
&kernel_attr_group);
return error;
}
core_initcall(ksysfs_init);